Zihan Wu

Ming Sun
email: bsunming@cau.edu.cn

Ling Zou

Colorimetric Detection of Mercury In Aqueous Media Based on Reaction with Dithizone

Keywords: Mercury, dithizone, colorimetry, spectroscopy

This study investigates the colorimetric reaction between dithizone and mercury in aqueous media which generate the orange Hg-dithizone complexes extracted by chloroform. Then combining with spectral analysis, the UV-vis spectral data of the complexes are obtained to build a forecast model. By means of the multiple linear regression model with SG smoothing method, RPD (Residual Predictive Deviation) of 3.2461 is reached with the detection limit of 0.1129 ug/L. This colorimetric method was found to be rapid, simple and sensitive for the detection of mercury in aqueous medium.

1 Introduction 1 There are two forms of mercury in nature, organic mercury complexes and inorganic mercury, which can change to each other forms dependent on the ambient conditions [START_REF] Selid | Sensing mercury for biomedical and environmental monitoring[END_REF].Pollution caused by heavy metals has negative effects on human health and the environment, which is from rock weathering and industrial emissions, volcanic movement [START_REF] Puiso | Biosynthesis of silver nanoparticles using lingonberry and cranberry juices and their antimicrobial activity[END_REF][START_REF] Huang | Selective gold-nanoparticle-based turn-on fluorescent sen-sors for detection of mercury(II) in aqueous solution[END_REF].Mercury can be passed by aquatic plants and animals through food chain to human bodies with long term bio-accumulation, which show great toxicity with little content. Mercury ions have a strong affinity with thiol groups in the body so that mercury ions could interact with substances which contains most thiol groups such as proteins and enzymes involved in the body's metabolism [4][START_REF] Gao | Old tree with new shoots: silver nanoparticles for labelfree and colorimetric mercury ions detection[END_REF][START_REF] Zargoosh | Highly selective and sensitive optical sensor for determination of Pb2+and Hg2+ ions based on the covalent immobilization of dithizone on agarose membrane[END_REF]. Therefore, finding a rapid and efficient method for the detection is of great realistic importance. For its detection, atomic emission spectrometry, high performance liquid chromatography and stripping voltammetry have been developed for detection of mercury in soil and aqueous samples, which need expensive instruments and usually need professional operators [START_REF] Maity | Colorimetric detection of mercury(II) in aqueous media with high selectivity using calixarene functionalized gold nanoparticles[END_REF]. Colorimetric detection is simple and rapid, which can read out with the naked eyes though most methods have been proposed [START_REF] Zhang | Core-shell structured mesoporous silica nanoparticles equipped with pyrene-based chemosensor: synthesis, characterization, and sensing activity towards Hg(II)[END_REF]. Reagent colorimetric method refers to comparing or measuring the colored substance solution or to measure the concentration of contents, based on chromogenic reactions that generate colored compounds.

Materials and Instrumentation

Materials

HgCl 2, Dithizone, carbon tetrachloride, sodium sulfite, nitric acid, distilled water were purchased from Yixiubogu (Beijing, China). All the chemicals used for the study were following the standard procedures.

35 ml mercury solutions with various concentrations are put into centrifuge tubes, separately. 2 ml sodium sulfite solution with 20% concentration is added to prevent dithizone from being oxisized. The pH value of the reaction solution is adjusted to 1.0 by using nitric acid and at last 10 ml dithizone solution with 2.5 mg/L concentration is dissolved in carbon tetrachloride. The reaction solution in the tubes is drastically Oscillated for 1 min, and Layered after being laid aside, extract the lower solution which is the complex (Hg-dithizone) generated by mercury and dithizone.

Instrumentation

RP1003H electronic balance and 78-1 magnetic heated stirrer were needed in the solution preparation process. UV-vis spectra of the complex are recorded on UV-2450 Shimadzu UV spectrophotometer.

Results and Discussion

Data preprocessing

The UV-visible absorption spectra of reagents in the colorimetric experiment are shown in Figure .1. It can be noted that the band for Hg-dithizone complex is at about 450 nm, which does not coincode with that of dithizone, indicating that dithizone has no effect on the absorbance of Hg-dithizone complex, even it over-doses. Other reagents used in the experiment also do not affect the absorbance of complex, and HgCl2 solution has no significant absorption peak. Consequently, the mercury concentration can be measured by the absorbance of complex. The UV-visible spectra of Hg-dithizone complexes with different concentrations are shown in Figure 2. In the paper, varieties of pretreatment methods on original spectral data are employed, such as Savitzky-Golay convolution smoothing (SG), derivative algorithm, multiplication scatter correction (MSC) and standard normal variate (SNV), after the models are set up. Least squares fit is applied as the digital filter after SG smoothing of the data, which makes the least squares polynomial fit to the data in a moving window and no longer a simple average operation. Derivative algorithm is used for obtaining the spectral intensity, whose basic idea is to select the original spectrum at several points to constitute a window and derivative spectrum can be obtained by deriving data in the window. MSC aims to obtain an ideal spectrum by correcting the scatter of samples. Firstly, assuming the contribution of scatter associated with the wavelength to spectrum to the composition is different; therefore, the spectral data can be divided into two parts. Since the absorbance value of each wavelength point should meet certain distribution (e.g. normal distribution) in every spectrum, the original spectrum subtracts the average of the spectrum, which is divided by the standard deviation of the spectral data, therefore, SNV is obtained.

The selection of relevant bands

Since the spectral data are from 300 nm to 900 nm, which include large amount of data to be processed, correlation coefficient is employed to select relevant bands. Therefore, the amount of computation is reduced without loss of information and the purpose of fast and efficient detection is achieved. Figure 3 shows the correlation coefficient between absorbance and the concentration of original data. It can be observed directly that among 460 nm -520 nm absorbance and wavelength has high correlation, and at 484 nm correlation coefficient reaches the maximum where the spectral data is used to build up a single linear regression. In addition, the spectral data at 470 nm, 480 nm, and 490 nm is used for multiple linear regression modeling and PLS modeling.

Fig 3 Correlation coefficient between absorbance and the concentration of original data

3.3Modeling results

This study employs three models for data analysis, that are single linear regression (SLR), multiple linear regression (MLR), partial least squares regression (PLS). Table 1 summarizes the results of different models combined with different data preprocessing methods. Therefore, the best model for prediction based on evaluation indexes is chosen. The paper adopts 5 evaluation indexes, that are multiple correlation coefficients for modeling set (Rc), multiple correlation coefficients for validation set (Rv), root mean square error of calibration for modeling set (RMSEC), root mean square error of prediction for validation set (RMSEP), ratio of the standard deviation to the RMSEP. The one of the most important indexes is Residual Predictive Deviation (RPD). If RPD values is greater than 3, the model for the detection of reagents is ideal and can be used for quantitative analysis. If RPD is from 2.5 to 3, the prediction accuracy should be improved. If RPD is less than or equal to 2.5, the model cannot be used for quantitative analysis. For the experimental data in the table 1, SG smoothing method has the best smoothing effect, by which noise is effectively eliminated to improve the signal-to-noise ratio. However both of SNV and MSC destroy the original spectral data, for both of RPD are smaller than 3. Noise is introduced when first-order difference and second-order difference are employed, which results in the signal-to-noise ratio reduced and a great deal of detail of the experimental data lost. When the differential width is too large, it will result in over-smoothing of the data.

High-precision Models can be obtained by SLR, MLR and PLS, but the accuracy of MLR model is better than both of SLR and PLS models, which is more suitable to process this data set. However, by PLS model, multicolinearity can be eliminated and RPD and other indexes can be improved. The results show that reagent colorimetric method is feasible to detect mercury in UV-vis spectrum.

Conclusions

In summary, a rapid, useful and sensitive colorimetric method for detection of Hg 2+ in aqueous solution was developed. Based on the spectral data, different methods of preprocessing combining with SLR, MLR and PLS models is employed to get the best forecast model. By means of the multiple linear regression model combined with SG smoothing method, RPD of 3.2461 is reached with the detection limit of 0.1129 ug/L, which suggests that combination of reagent colorimetry and spectroscopy may be the one of the best approaches for detection of mercury in aqueous media, which can also be expanded to for the qualitative and quantitative estimation of other heavy metal.

Fig 1

 1 Fig 1 UV-visible absorption spectra of reagents in the colorimetric experiment

Accepted date: 201X-XX-XX *Corresponding author: Ming Sun, Ph

  .D. Professor, College of Information and Electrical

	Engineering, China Agricultural University, 100083, China. Email:sunming@cau.edu.cn. Tel:
	135-2055-7807.

1 Received date: 201X-XX-XX

Table 1 .

 1 Results of different models combined with different data preprocessing methods

				Model evaluation indexes
	Model	Pre-process methods
			Rc	Rv	RMSEC	RMSEP	RPD
		Original data	0.9442	0.9880	0.1301	0.3448	3.1006
		MSC	0.9401	0.9114	0.1347	0.3315	2.9963
	Single linear	SNV	0.9367	0.8834	0.1383	0.3417	2.9175
	regression	SG	0.9459	0.9888	0.1282	0.3445	3.1487
		First-order differential	0.5587	0.7158	0.3276	0.2469	1.2317
		Second-order differential	0.2779	0.2668	0.3794	0.2096	1.0634
		Original data	0.9526	0.9864	0.1201	0.3610	3.3590
		MSC	0.9407	0.9214	0.1340	0.3306	3.0111
	Multiple linear	SNV	0.9388	0.9260	0.1360	0.3270	2.9664
	regression	SG	0.9492	0.9905	0.1243	0.3185	3.2461
		First-order differential	0.7949	0.8307	0.2397	0.3520	1.6834
		Second-order differential	0.3192	0.3313	0.3743	0.2625	1.0779
		Original data	0.9458	0.9895	0.1282	0.3460	3.1454
		MSC	0.9396	0.8992	0. 1352	0. 3386	2.9845
	Partial least	SNV	0.9376	0.9049	0.1373	0.3340	2.9381
	squares regression	SG	0.9461	0.9900	0.1279	0.3460	3.1531
		First-order differential	0.7614	0.8944	0.2560	0.3072	1.5758
		Second-order differential	0.3186	0.3253	0.3744	0.2593	1.0776

Acknowledgment

Fund for this research is provided by the Public Service Sectors (Agriculture) Research and Special Funds for Modern Fishing Digital and Physical Networking Technology Integration and Demonstration (No.201203017).


Dingfeng Wu

Jian Wang
email: wangjian02@caas.cn

Guomin Zhou

Hua Zhao

A Research On The Task Expression In Pomology Information Retrieval

Keywords: pomology information retrieval, task, task expression

By analyzing the progresses of pomology information retrieval which are driven by tasks, the author put forward an idea of expressing the tasks in pomology information retrieval. An interview test was used to validate the idea and based on analyzing the data of the test, a method of expressing the tasks in pomology information retrieval, in which the difference of searchers'acknowledgement is considered,was put forward.

Introduction

With the rapid rise of agricultural websites and databases, the research of agricultural information retrieval is becoming more and more important to agricultural industry and agricultural scientific research. The study on information retrieval is now undergoing a great change from simply focusing on the statistical model and the mathematical algorithm to considering about the situation factors, such as user needs, job tasks, social environment and so on [START_REF] Ingwersen | The Turn Integration of Information Seeking and Retrieval in Context[END_REF] . Within those circumstance variables, the job task is very important [START_REF] Kelly | The effects of topic familiarity on informationsearch behavior[END_REF] . The researchers announced that the users' information retrieval behavior originated from their information needs, and the information needs caused by the job tasks, so the job tasks became the driving factors of the information retrieval behavior [START_REF] Ingwersen | Information Retrieval Interaction[END_REF] . Apperceiving the users' job tasks can help the IR system to understandthe users' intention and improve the precision of information retrieval system.To achieve this, the users'abstract tasks must be describedin a specific way.

Theideaofthetaskexpression in pomology information retrieval

By observing and analyzingthe pomology information retrieval process, we found that in pomology information retrieval, a user have to master some pomology knowledge which is necessary to complete hisjobtask [START_REF] Kelly | The effects of topic familiarity on informationsearch behavior[END_REF] . By taking that pomology knowledge, a userupgraded his pomology knowledge structure to which we called target pomology knowledge structure of the task. When there is a gap between the target pomology knowledge structure and the inherent pomology knowledge structure, the information retrieval behavior will be triggered to make up the gap. We believe that the pomology knowledge gap often consists of some sub pomology knowledge gaps and that's why a series of interrelated information retrieval behavior often be observed together.Because every information retrieval behavior corresponds to a retrieval request query, so in pomology information retrieval, tasks can be expressedin to a series of retrieval queries. Fig 1 shows a typical pomology information retrieval processdriven by job task. The user input two related retrieval request to make up the knowledge gap andupgraded the inherent pomology knowledge structure to the target pomology knowledge structure.In this process, task eventually expressed as a series of information retrieval queries.

The user Job task

The inherent pomology knowledge

The target pomology knowledge

Pomology IR Process

IR behavior 1 (make up a sub knowledge gap) IR behavior 2 (make up other sub knowledge gaps)

Query1 Query2

Fig. 1.A progress of pomology information retrieval which is driven by a task

Materials and methods

In order to verify the assumption mentioned above, we interviewed the users of the pomology information retrieval system. In the interview process a large number of simulated job tasks were arranged and at information retrieval process were recorded and analyzed.

The participants including pomology scientific researchers, agricultural experts, scholars and orchard workers, all of whom had the experience of using pomology information retrieval system. The experiments took place at two places, one was the realityexperiment site which was at the 101 room of office building of Pomology institute of CAAS, the other one was the Internet remote site, whichused the instant messaging platforms, screen recording software, microphones and other video and audio signal capture tools to ensurethe real-time communication between the participants and the experiment assistants and record the details of test results and test information behavior.

The setting of the simulation tasks is one of the key problems to be solved of the experiment design. Simulated tasks need to satisfy two conditions: for the first, It must be closely related to the pomology production and scientific research, and it is better to be derived from the practice of production and scientific research in order to be accepted by the participants. For the second, Must have some complexity, in order to identify the change of the ideas of the participants in the IR process, so the simulated tasks should not be single information search tasks but be tasks with practical background and realistic objectives. The source of the work task is provided by the participants themselves, that's because that a lot of typical and impression tasks were accumulated by the participants in their past pomology production and scientific research. The benefit of using the experienced tasks is that the task can be accepted by the participants easily and the retrieval behavior will be simple and intuitive to analyze since the participants are familiar with the tasks. Before the experiment, serval tasks should be prepared in case of the participants can provide few tasks.

In order to extract the intention of every information retrieval behavior smoothly, during the experiment, the participants were asked and guided by the experiment assistants to help them to expose their own aim of every search behavior. The search intention can be exposed in the two part of the experiment. The one is when the retrieval query was typed in, the query directly reflects the information retrieval intention. It should be noticed that sometimes it is difficult to find out a suitable query which can reflect the intention of participants accurately, so a lot of queries are ambiguous, incomplete, or too general. In response to the above situation, the experiment assistants have to ask questions to clarify the intent of the participants, sometimes even help the participants to get queries which are more suitable. The other one is when the participants do the relevance judgment after they get the result list. Usually, the result list is a superset of information and knowledge which the participants need, so the participants can be lead to express the judgement results and evidences which can further exposure the search intentions when the relevance judgments are being carried out.

Data and Analysis

There were eleven participants in this experiment who completed twenty-six virtual tasks. During the experiment, seventy-nine information retrieval behaviors are observed.

Theretrieval intention can be obtained when analyzing the queries and the relevance judgment behaviors. The users intention can be divided into the following three classes: get the Knowledge points which directly related to tasks (intention 1), get the facts related to the tasks (intention 2) and get the Information that has nothing to do with the tasks (intention 3).If the results of the analysis of the query and the analysis of the relevance judgment behaviors are the same, it is concluded that the conclusion is drawn, but if they are different with each other, the intention obtained from the analysis of the relevance judgment behaviors will be accepted firstly. If there are multiple intentions, It is suspected that multiple information retrieval intents may be merged intoone information retrieval behavior and that behavior should be departed into many sub-behaviors to be analyzed. On the basis of analyzing every information retrievalbehavior, the participants' intentions can be counted out as shown in Table 4-1. Experimental data shows that during the pomology information retrieval process, 80%

Table.1 The Statistical results of information retrieval intention

Tasks

of the retrieval behavior is focus on the Knowledge points which directly related to tasks, 16% of the retrieval behavior is around the facts related to the tasks which can suppose the users to deduce out the knowledge points they need, the remaining 5% are unrelated to the tasks. Considering about the reason of the information retrieval behavior, we found that job tasks are the most important driving factor which leads to several times more information retrieval behavior than the other factors. Only the task 15 is an exception, that's because in task 15, the participants were asked to find out the treatment method of the apple bagging black spot disease which is rare and lack of research, so the participants have to look for the potentially useful information by searching other similar diseases.

Twenty-six simulation tasks in the experiment include five categories: pomology disease information, pest information, variety information, breeding information and pomology cultivation techniques [START_REF] 王中英 | [END_REF] . We found that different participants will look for different knowledge points when facing the same tasks and this phenomenon might because that their inherent knowledge structures are different. For example, when facing a task which asks the participants to find out the treatment method of a pomology disease, the plant protection professional participants are more inclined to search methods and new drugs, but the other professional participants usually look for the Mechanism and symptoms of the disease firstly. A possible explanation of this phenomenon is that the plant protection professional participants only had few knowledge gaps to make up, so they only need to look for the information which most urgent need to confirm. Relatively speaking, the other professional participants who are not so familiar with pomology diseases have more gaps to fill, so they need to get the basic information first. For the same reason, we noticed that when facing sometasks which are in the same category, a participant might use different Search strategy.

Conclusion

Through the above analysis, it is proved that a job task can be expressed as a series of information retrieval intention and further expressed as a collection of queries. If we do not consider the relevant knowledge structure, the job task can be expressed as a collection of queries for all the knowledge points needed for the task. A task can be represented by the following formula:

Task → {Query 1 ,Query 2 ,…,Query n }

If we consider about the participant'slevel of familiarity of the task, the weights should be added to the elements in the collection, if F 1 ,F 2 ,…,F n represents the level of familiarity with the knowledge points and P 1 ,P 2 ,…,P n represents the weights of queries in the collection, the task can be expressedas the following formula:

Task → {P 1 Query 1 ,P 2 Query 2 ,…,P n Query n } P k = 1/F k k∈ [1,n] If the user is particularly familiar with the knowledge point, F k trend approaches infinity, P K is approaching zero, the expression of the task will not contain Query k .

On the contrary, if the user is not familiar with the knowledge point, the weight of Query k will increase.

Acknowledgements:Funding for this research was provided by "Agricultural system intelligent control and virtual technology team of Science and technology innovation project of CAAS" (CAAS-ASTIP-2015-AII-03)


Xiaolan Li

Bingbo Gao
email: bgaobb@nercita.org.cn

Yuchun Pan

Yanbing Zhou

Xingyao Hao

The synchronized updating technology research of spatio-temporal supervision data model about organizing of construction landuse data in distributed environment

Keywords: distributed, spatio-temporal supervision data model, synchronized update, consistency, integrity

Abstract: As China advances toward urbanization, the relation between supply and demand of land use is growing acutely. Effective supervision of various land use has become necessary to achieve reasonable and lawful use of land. The change of land use from farmland or unused land to construction land use in the process of urbanization usually undergoes the following stages: approval, expropriation, provision, application, and supplement. The change to construction land use similarly undergoes this process, and then the outcome before and after the change is compared to determine potential land use problems. The present process-oriented spatio-temporal data model for organization and supervision data management records the supervised spatio-temporal variation process and state by using new-added auxiliary tables. This model can efficiently organize and demonstrate multiple relationships among landuse stages and the evolution process in the life cycle of spatial entities. To achieve effective supervision from the upper to the lower in the three-level "province-city-county" distributed environment and to detect potential land use problems early, data from different places are collected and synthesized for analysis. To ensure that the database is up-to-date, real-time synchronization of spatio-temporal supervision data should be studied and the integrity of the spatio-temporal data model should be maintained. Therefore, this study introduces an updating mechanism based on the trigger technology for data synchronization.When importing basic data from distributed databases into the supervision database, simultaneous updating in related auxiliary tables is performed along with changes in the basic tables. That is, records are added automatically into auxiliary tables that reflect the spatio-temporal change of the process and state when basic data are imported. This method not only achieves and maintains consistency in the database, but also ensures integrity and currency in the auxiliary tables. Change information can be expressed duly in all supervision stages ,and highly efficient supervision of construction landuse is guaranteed.

1.Introduction

In the urbanization process of China, the relation between land supply and demand is increasingly becoming distinct. With the aims of controlling construction land use growth rate, strengthening regulation to achieve economical and intensive land use, and preventing unreasonable or unlawful use of land use, the process of approval, supplement,application, expropriation, and investigation of construction land use must be supervised [START_REF]Ministry of Land and Resources of the People's Republic of China. Circular on strengthening the supervision and administration of construction land[END_REF] .In the supervision data of construction land use in the urbanization process, a certain flow and life cycle are demonstrated in approval, expropriation, provision, application, supplement, and investigation these stages. Hence, vertical supervision, aside from horizontal analysis at these stages is necessary [START_REF] Zong Hua | Realizaiton of Construction land dynamic supervision based on high-dimentional attribute intelligent fusion[END_REF] .In the current supervision systems, land use data of related stages are scattered in thematic databases, and only the land use data of the current stage are supervised. Supervision data in different databases lack a dynamic connection, thereby resulting in difficulty to achieve full supervision of urbanization land use from the perspective of horizontal correlation [START_REF] Jiang Wenjuan | Research and construction of authorized supervision system for land expropriation and supplying[END_REF][START_REF] Qiuying | The establishment and application on information system of construction land approval management of Wuhan[END_REF] .

With this demand, Gao Bingbo et al proposed a process-oriented spatio-temporal supervision data model for construction land use [START_REF] Bingbo | Process-oriented spatio-temporal data model for organizing and management of supervision data of construction land use[END_REF] .On one hand, this model introduces an improvement to the database structure to suit existing supervision data and constructs the incidence relationship among approval, supplement, application, expropriation, and investigation land use stages. On the other hand, auxiliary tables are employed to record the evolution process of related land use entities and determine multiple relationships among land use stages. This model realizes the supervision of urbanization development, including the recording of change processes to allow review of land use entities and reconstruction of land use projects, and improves the efficiency of supervision of construction land use.

In the process-oriented spatio-temporal supervision data model for construction land use, supervision data on land use are analyzed. Basic geographic data and thematic data are collected from different places to achieve efficient supervision of construction land use. In China, land use management databases and other related business systems are distributed vertically at three levels: "province-city-county" [START_REF] Dangsheng | Examination and approval mechanism for provincial,municipal and county database update of second land investigation[END_REF] . Data are obtained from different systems that are distributed in different network nodes. In the importation and updating of related supervision data in the "province-city-county" distributed environment, related change information should be reflected in the supervision database system duly. That is, when data in basic tables from the corresponding levels change, the auxiliary table should reflect such change to ensure consistent and up-to-date information in the supervision database.

The problem of synchronized updating of the entire supervision database will be discussed in the succeeding section.

This study introduces a synchronized updating technology for the spatio-temporal supervision data organization model for construction land use in a distributed environment. The role of this technology in maintaining the consistency of database is analyzed.

2.Organization of supervision data in the spatio-temporal database

Supervision of construction land use refers to both vertical and horizontal supervision of the approval, supplement, application, expropriation, and investigation stages of the entire land use process. Land use starts from the application for approval of new construction land projects and ends with the completion of the construction project. To determine the construction land project and the land use entities involved at a certain time, the state of land use should be reconstructed at a specific moment. Gao Bingbo proposed a process-oriented spatio-temporal data organization and management model in construction land use supervision based on the requirement mentioned previously.

In the model, the basic data of each link are connected with each other in a certain manner. The evolution of land use entities in the approval, supplement, application, expropriation, and investigation stages is the foundation to construct the correlation among these stages. The storage structure of basic supervision data is shown in Figure1. In every two links, "consolidation, reclamation, and development" land use projects and supplementary cultivated land projects are connected by supplementary cultivated land use entities. Meanwhile, supplementary cultivated projects and approval projects are connected by the approval project serial number. The relationship between the approval project and expropriation project is established by expropriated land entities. The relationship between supplement and expropriation projects, which is much more complex, is established through the relationship between related supplement project and approval project and that between related approval project and expropriation project. The application project and supplement project are connected by related application land use entities. The vertical correlation between two links is established in the same manner, thereby allowing vertical supervision in the system by vertical association. The traceback of supervision data mainly includes the spatial form or property of land use entities and the spatio-temporal process of approval, expropriation, provision, application, supplement, and investigation in land use two parts. The traceback of the evolution of land use entities can be achieved by examining the state and evolution tables. The traceback of the spatio-temporal process requires a step-by-step analysis of the evolution, sequence, and process tables to obtain land use project information at a certain time. In reconstructing the historical state of land use entities, the existence of land use projects and entities can be analyzed using the process and state tables, while the information of reconstructed land use projects and entities can be obtained using the sequence and evolution tables.

Storing evolution information of spatio-temporal processes and entities by using auxiliary tables is more intuitive because these tables increase the operational and practical review and reconstruction work of supervision data and reduce the complexity of supervision operation that requires different supervision data at multiple time periods. Consequently, the efficiency of construction land supervision is improved.

3.Construction land use supervision database in a distributed environment

3.1Supervision data flow in the "province-city-county" network

Supervision data mainly comprise basic geographic data, land use data at approval, expropriation, provision, application, supplement, and investigation stages, and thematic data. In the "province -citycounty" network environment, three types of data are distributed in different network nodes and business systems. These data are extracted from other related databases or systems between two levels.

The flow of supervision data in the distributed environment is shown in Figure3.

In general, land use data at approval, expropriation, provision, application, supplement, and investigation stages in the "province-city-county" environment are complex. Databases at the top, bottom, or same levels must be accessed to extract related data at each corresponding stage. The supplement data in the supervision database at the county level contain consolidation, reclamation, and development data that are then imported into the supplement database at the city level. The supplement data of different cities are subsequently imported into the supplement database at the province level.

The approval data are obtained from the electronic government affairs systems at the county level.

City-level approval data can be extracted from the data at the county-level or from the electronic government affairs systems at the same city level. Province-level approval data are from the land resource remote reporting system or the provincial e-government affair system that gathered data from the subordinate level. The county-level expropriation data are extracted from the land reserve database, while the expropriation data at the city level is gathered from the related county data, and the provincial expropriation data is formed from city nodes with the same way.

Figure 3. The supervision data flow status in "province-city-county" distributed environment

In the upper analysis, related land use systems distributing scattered and system structures are found to vary in the" province -city-county "distributed environment. The data at different levels and in different business systems are obtained manually. Thus, the collection of full supervision data and supervision efficiency are affected. A high degree of automation of the data flow would clearly increase the satisfaction level of supervision business needs. Therefore, the current supervision data flow should be changed to a new and more adaptive data flow in such distributed environment.

Synchronization of construction land supervision data in a distributed environment

In the construction land supervision database, we use the model proposed by Gao Bingbo in storing supervision data. The supervision database is deployed in the distributed environment characterized by a three-level, "province-city-county" vertical management mode. We set provincial, city, and county supervision nodes, and the county and city nodes interact and share data with each other, as well as the city and provincial nodes, thereby achieving a top-to-bottom control and effective management. The interaction among nodes is shown in Figure4.

County supervision node

County supervision node County supervision node

City supervision node

City supervision node

City supervision node Provincial supervision node

Figure 4.Construction land use supervision database management system in "province-city-county" three-level network environment

In the" province-city-county "network environment, we need to consider the content of two aspects in constructing the supervision database. One aspect is the corresponding relationship among different business data, such as basic geographic data and land use data, and the other aspect is the corresponding relationship between province and city nodes or between city and county nodes. The basic tables in the supervision database contain three types of data: geographic data, land use data, and thematic data. Geographic data could be obtained from superior level nodes of "province-city-county" network. Thematic data could be extracted from the a-map system at the same level. Land use data could be collected from subordinate level nodes by subscription and use of distribution technology on a certain interface. Lastly, data in auxiliary tables could be obtained from basic tables. When the data in basic tables are updated, related records in auxiliary tables are also updated. Figure 5 shows the new data flow of the construction land supervision database system in the distributed environment. In the new data flow, the superior database could gain data from subordinate databases by subscription and use of distribution technology based on the data service. Data service is used to package the data in each level and to provide access by deploying a responsive distribution service, registration service, and subscription service at a superior platform. Data service is equipped with the functions of service registration and real-time data push. Service information is registered to the registration service, and then the changed data is pushed to subscribers in real time. Subscription service uses the information registered by the data service. The subscription mission is registered in the registration service, and related data are relayed to the receiving interface. Distribution service receives the pushed data, charges the execution of subscribed data, and pushes changed data to the interface of the subscription service.

Registration service maintains the registered information of the data service and the subscription mission and activates the subscription service to execute data push as the subscription mission. The concrete process of data acquisition is as follows: First, data are distributed by publishing the data as data service in a subordinate database server that requires superior synchronized updating. These data are then registered in the registration service. Second is the subscription of data. The subscription service at a superior-level platform creates subscription mission and registers on a registration server according to the current distributed land use data service. When data are changed, the data service will push changed data to the subscription service. The registration service will simultaneously activate the data distribution service according to subscription mission and send the changed data to the subscription service.

The previously described process can ensure the automatic updating of the database at the superior level as the data of the basic tables change at the subordinate level. Consistency is consequently guaranteed. However, the supervision database management system not only includes the basic tables, but also the auxiliary tables that contain data from the basic tables. As mentioned earlier, when the data of the basic tables are updated, the auxiliary tables must have a certain mechanism to create related records based on the basic supervision data and then form the topological relationship information of the spatio-temporal process. In this new data flow design, the integrity and up-to-date quality of the entire supervision database system are maintained, subsequently ensuring the accuracy and efficiency of supervision work.

4.Automatic maintenance of construction land use supervision data in distributed environment

The data in a distributed database are decentralized or stored in different physical location nodes. For the management system to be consistent, data in different nodes should remain consistent while mutual exchange or sharing between certain databases occurs. For these cases, the DBMS manufacturers have designed a mechanism, such as Oracle's advanced replication technology [START_REF]oracle8 Distributed database system[END_REF] and SQL Server's subscription replication technology [START_REF]SQL Server Replication Revealed[END_REF] ,to achieve data synchronization and automatic maintenance.

Some researchers have also studied synchronization and automatic maintenance from different perspectives and carried out many data synchronization technologies and methods [START_REF] Liugao | Study on data consistency in distributed database system[END_REF] ,such as the Oracle technology [START_REF] Kun | Research of data synchronization technology in distributed database[END_REF] , the multicast form in updating the database [START_REF] Wei | Design and implementation of data synchronization based on distributed memory database[END_REF] ,the reduction method based on the SQL operation statement [START_REF] Haiming | The research and implementation of heterogeneous database synchronization technology based on SQL reduction method[END_REF] , and the data synchronization and updating technology for land use data [13][14] .All these mechanisms can satisfy synchronization needs and automatic database maintenance.

However, for the process-oriented, spatio-temporal supervision database management system, the relationship between basic and auxiliary tables is derived, and the traditional synchronization technology could not contain basic and auxiliary tables in the same database to allow synchronized updating and to maintain integrity. Therefore, further research on database synchronization technology is necessary.

In a distributed environment, the spatio-temporal supervision data model for construction lands includes not only the basic tables that contain land use information at each stage, but also the auxiliary tables that exhibit the association among land use projects and the evolution among land use entities.

The model can reflect the evolution process of land use entities in their life cycle and backrtrace or reconstruct the land use stages at particular instances using this form. As shown in Figure 6,the auxiliary tables have a close derivation relationship with the basic tables. The process table corresponds to different land use projects, the sequence table records the association between two different land use projects, the status table records land use entities and their duration, and the evolution table expresses the evolution process between entities. A corresponding relationship is present among basic tables, as well as a derivation relationship between basic and auxiliary tables. When basic table data are imported, data in auxiliary tables must be updated to maintain the integrity of the entire database.

Land use project tables

Process table

Land use entity tables

Status table

Sequence table

Evolution table

Figure 6.The relationship of basic tables and auxiliary tables

Considering the characteristics of data in the approval, expropriation, provision, application, supplement, and investigation stages and the four auxiliary tables comprehensively, a spatio-temporal data synchronization and updating mechanism is developed in this study based on the combination of the trigger and the traditional land use database synchronization and updating technology. Figure 7 illustrates this developed mechanism and the specific description.

" development,consolidation and reclamation"land project

Figure 2 .

 2 Figure 2.The four tables indicate the correlation of land use processes and the evolution information of land use entities in construction land supervision. In the basis of these auxiliary tables, we can immediately reconstruct the relationship among land use projects and recall land use entities. As a result, the historical state of construction land entities at a particular instance in a time series will be easy to extrapolate.

Figure 2

 2 Figure 2The storage structure of auxiliary table data in supervision database.

Figure 5

 5 Figure 5 New data flow of construction land supervision database system in distributed environment

  The provision data in county nodes are encoded manually, while the city-and province-level expropriation data are gathered from lower-level nodes. The application data at county level are obtained from the law enforcement and inspection processes. The city-level application data are extracted from subordinated county nodes,and the provincial application data are gathered from the same but lower county nodes.The supervision database uses a series of indicators. Basic geographic data and thematic data are required as reference data, and land use data at approval, expropriation, provision, application,

	Basic Geographdata	Supplement	Approval	Expropriation	Provision and application			Investigation	Thematic data
	Basic province	Supplement		Province E-government affairs system	Province land reserve system							Investiga-tion data	Province A-map system
	data distribution	data		Approval Data	remote reporting system Land resources	Expropria-tion data			Provision and application data		Summary	ed results investigat Cases	system A-map Province
	Basic data city	data Supplement Business supervision system	munual munual	City E-government affairs system	approval	City land reserve system	munual	munual	Provision data		munual		Cases Investiga-tion data	system A-map City
												summary	investigat
		Supplement data		Approval Data	approval	Expropria-tion data		munual	data Provision and application	munual		ed results	system City A-map
	distribution						munual
	data Basic county	Land develoment consolidation reclamation Supplement data	County E-government affairs system Approval Data	Data Approval approval	Expropria-tion data County land reserve system	-iation data Expropr	Provision data	Investiga tion	Application data	cases Document	ed results Cases investigat-Investiga-tion data	system A-map County system County A-map

supplement, and investigation stages are checked if reasonable and legal to identify potential problems.

The basic geographic data are propagated by the Ministry of Land and Resources to provinces, cities, and then to counties, forming the three-level, "province-city-county" basic geographic database. The thematic data in the supervision database are extracted from the province-level, city-level, and county-level a-map databases in the distributed environment.

Acknowledgment

Funds for this research was provided by the National Science and Technology Plan Projects (2013BAJ05B01).

(b) When data are imported into the basic tables that contain data of the projects or programs at the approval, expropriation, provision, application, and supplement stages, two triggers, namely, before and after triggers, will be generated. In the supervision database, "supplement" corresponds to the supplement program in the approval project, and the application project has the same series number as the provision project; this series number is a unique key in the database. After the activation of the after trigger as data are imported into current land use basic tables, the process table creates related records.

The before trigger is activated to check if the last stage of the project or program exists. The current stage data could be imported successfully based only on the existence of the data of the last stage. In the database, the importing operation of the provision program must be performed after the importing operation of its related approval project. For the application project, the provision project should be imported first and then the related land monitor information is obtained. The entire spatio-temporal supervision data of projects or programs should be imported into corresponding project or program tables in the following order:(1) consolidation, reclamation, and development project, (2) approval project, (3) supplement program in approval project, (4) expropriation project, (5) provision project, and (6) application project.

(c) When data are imported into the basic tables that record information on land use entities at the approval, expropriation, provision, application, and supplement land use stages, two triggers, namely, before and after triggers, are generated. The application land use entities are provision land use entities.

The after trigger is used to add records into the status, sequence, and evolution tables, while the before trigger is used to check if the land use project, which is related to the current land use entity, exists. The importing operation of land use entity data should be followed by the importing operation of related land use project or program data. The entire spatio-temporal supervision data about land use entities should be imported into corresponding basic tables in the following order:(1) consolidation, reclamation, and development entities, (2) supplement entities, (3) approval project, (4) expropriation entities, and (5) provision entities.

In the distributed environment, to maintain the consistency and integrity of the database system, we can use the previously described synchronization and updating technology to import data using the principle "first land use projects, then land use entities."Based on the trigger technology, when land use project data are imported, the mechanism will synchronize and update the process table. When land use entity data are imported, the mechanism will synchronize and update the status, sequence, and evolution tables. Updates in basic table contents should also correspond to updates in auxiliary table records to maintain consistency and integrity of the construction land spatio-temporal supervision database and to ensure that all data are up to date. The entire process of tracing is performed quickly ,thereby considerably enhancing vertical supervision efficiency.

The synchronization and updating technology ensures that the auxiliary tables are updated when the data are imported in the basic tables. This updating technology, which is based on the trigger mechanism of the database, is much more efficient than the synchronization and updating system proposed by Fu Zhongliang et al., which uses specific algorithms [START_REF] Zhongliang | Design and implementation of marinebase library synchronization update system[END_REF] .As the basic technology of the database, trigger is more effective than the extended program module in immediately responding to changes and in constructing the spatio-temporal topological relationship. Compared with the method that uses spatial data to check and record changes in the spatial database, which was carried out by Zhangjian [START_REF] Zhang Jian | Research of spatial data real-time synchronization technology in PGIS[END_REF] ,the technology reported in this paper does not require spatial operation and the use of log records. The auxiliary can reflect the spatial data change information indirectly, rendering the complex spatial operation unnecessary, and the trigger works on the auxiliary tables directly, thereby simplifying the updating process. Efficient supervision of spatio-temporal data of construction land use is also ensured.

5.Conclusions

In the current "province-city-county" distributed environment, the construction land use spatio -


Xiaohui Shi

Tian' En Chen

Evaluation Model of Tea Industry Information Service Quality

Keywords: tea industry, information service quality evaluation, multiple regression; R-cluster

According to characteristics of tea industry information service, this paper have built service quality evaluation index system for tea industry information service quality, R-cluster analysis and multiple regression have been comprehensively used to contribute evaluation model with a high practice and credibility. Proved by the experiment, the evaluation model of information service quality has a good precision, which has guidance significance to a certain extent to enhance the information service quality of tea industry information website.

Introduction

According to characteristics of tea industry information service, and based on analysis of the evaluation goal for tea industry information service quality, the typicality of index system as the main direction, also takes the information requirements characteristic of users into account, the key factors influencing the quality of information service have been analyzed from platform function, platform information, platform design, platform framework and platform efficiency, then select 5 first grades and 30 second grades. 30 second grades are clustered by R-cluster analysis, finally forming an evaluation index system consists of 5 first grades and 17 second grades. Based on the influence factor of information service quality analyzed by information service quality evaluation model built with multiple regression, which will give a scientific guidance for tea industry information service.

Analysis Methods

2.1 R-cluster R-cluster [START_REF] Chen | Website quality evaluation optimization based R-cluster[END_REF] is one kinds of the cluster analysis method, is adequate for lots of variable, and variable with a high correlation, its purpose is to cluster the variables in the same group, and find the representative variables to achieve the purpose of dimension reduction. In R-cluster theory, N objects are treated as N groups, the correlation coefficient around the groups is R,two groups having the biggest related coefficient are clustered in one groups, until all groups are clustered in one big group.

Multiple Linear Regression

Brief Introduction for Multiple Linear Regression Model

Multiple linear regression [START_REF] Sun | Temperature Errors Modeling for Micro Inertial Measurement Unit Using Multiple Regression Method[END_REF] model is one kinds of math model to consider the relationship around variable x 1 , x 2 ,…, x p and variable y. Assuming y is change along with the changes of x 1 , x 2 ,…, x p .

The mathematical expression of multiple linear regression is Y=W

Selection Criteria of Independent Variable for Multiple Linear Regression Model

Multiple linear regression model has advantages, such as simple method and high precision, when it simulate the data owning pure linear relationship, but having bad results in this situation of data is nonlinear relationship or data missing. In order to guarantee the excellent predictive results, the selection criteria of independent variable are summarized as follows: 1) independent variable has a outstanding influence with dependent variable, and there is a close linear relationship; 2) linear relationship between independent variable and dependent variable is true, not in form; 3) a certain mutual exclusion between the independent variables is necessary; 4) independent variable must have integrated data [START_REF] Sadhuram | Simple Multiple Regression Model for long range forecasting of Indian Summer Monsoon Rainfall[J][END_REF].

Index System

Preliminary Index System

Selecting platform function, platform information, platform design, platform framework and platform efficiency as the first grade indexes [START_REF] Wang | Analysis and Comment on Study and Application of EC Websites Evaluation[END_REF], and every index is further segmented, finally forming 30 second grade indexes, which forms the service quality index system for tea industry information platform, the specific indexes are listed as follows:

Index System Selection

Normally, the method of principal component analysis is used to solve a problem which contains lots of evaluation indexes, but the results from principal component analysis depend on measured value of primitive index, so principal component analysis only solve simplification of quantitative index, not the descriptive index before quantitative [START_REF] Zhao | Information service quality evaluation for industry information center website[END_REF].

In this paper, R-cluster is adopted. According to the correlation coefficient in indexes, all indexes are clustered by R-cluster, the demand of accuracy finally determines how many groups will be segmented, select the typical index in one group represent multiple indexes to achieve the purpose of simplified index [START_REF] Pei | Research on User -Oriented Appraisal Framework of Website Information Service Quality[END_REF].

Assuming there are P indexes u 1 , u 2 , u 3 , …, u p ; N experts score for the relative coefficient among the indexes, the relative coefficient matrix after scoring is expressed in following table, and the cluster results are expressed in. To combine the results of cluster, comprehensively considering the simplicity, representation and feasibility of indexes, analysis results are carried out as follows: when the minimum distance of correlation coefficients is under 0.03, the jumping points are obvious, indexes are clustered 17 groups. So, the results represented as follows: R 1 :

Experts Estimation

After the establishment of indexes system, expert estimation has two parts:

(1) General part indexes existing in traditional information service website or system. After the establishment of indexes system, select the typical tea information website, then let the experts who is good at agricultural informationization estimate the quality of information service websites and the indexes that influencing the quality of information service.

(2) The indexes part reflecting the characteristics of cloud service platform. Because of tea industry information cloud service platform in domestic is still blank, there is no quantitative index to be verified, only the experts' view as the reference, that is means, when tea industry information cloud service platform is built, the 7 indexes, such as X23: Platform stabilization,X24: Platform compatibility,X25: Platform safety,X26: Platform adaptability,X27: Platform expensibility,X28: Software deployment simplicity and X29: Software operation shortcut will be fully considered.

Data Processing

First step: website selection. Tea information websites are divided into two groups: one group is comprehensive agriculture websites but covering content of tea industry information, another group is the professional tea information websites. The objects of this experiment are 40 websites in two groups, 18 comprehensive websites, such as agriculture information websites belong to province and municipal district, and 22 professional tea information websites, specific situation is listed in table 3.

Table 3. Objects of experimental evaluation for tea information sites

Groups Website

Second step: data acquisition. Experts estimate the 10 second indexes belong to Platform function, Platform information and Platform design in table 9, information service quality and indexes estimated by quantitative evaluation, the scores are during 0-1, adopt the method of integrating multiple scores, the data is listed as table 4 after data processing.

Selection of influencing factors

Before the influencing factors are finally selected, the correlation between information service quality and influencing factors needed to be analyzed respectively. The purpose of correlation analysis is to represent the correlation situation and its change rule between variables, and find the correlation model with each other, which can provide references for making the next decision.

Null hypothesis of test is correlation coefficient of two variables expressing 0 in totality. The process of correlation analysis in SPSS shows the probability of hypothesis formation [START_REF] Zhi | Multidimensional Statistic Analysis [M[END_REF].

On the SPSS 18 platform, data correlation analysis respectively is produced between Y and X 1 , X 2 , X 4 , X 5 , X 9 , X 10 , X 12 , X 16 , X 19 , X 22 . Correlation between Y and X 2 , X 4 , X 5 , X 9 , X 10 , X 16 , X 19 , respectively is obvious, and shows linear relationship, and these indexes can be selected as the influencing factors for Y, so multiple regression model is established.

Experiment Analysis

On the platform SPSS 18, multiple regression model has been established, X 2 , X 4 , X 5 , X 9 , X 10 , X 16 and X 19 as independent variables, Y as dependent variable. Results of multiple linear regression show that X 2 , X 4 , X 5 , X 9 , X 10 , X 16 , with Y shows the positive correlation respectively, but the estimated value of regression coefficient for X 19 shows negative correlation, which is not fact, so estimated value of X 19 is not believable [START_REF] Chen | Agricultural Information Service Quality Evaluation Model Based on Factor Analysis and Multiple Regression[END_REF], then eliminate variable X 19 . Second regression is carried out. R 2 of model is 0.999, adjusted R 2 also is 0.999. Value of F tends to rationality. To a certain extent, model reflect the relationship for information service quality and influencing factors, finally the influencing factors model of information service quality is carried out as follows: Y=0.075+0.100*X 2 +0.005*X 4 +0.368*X 5 +0.025*X 9 +0.481*X 10 +0.020*X 16 .

Model Test

The established multiple regression model is tested by test data. Table 5 shows that results of 10 test data present ideal results, relative errors between predictive value and real value all are less than 3%, and average error is only 1.01%. Experiment demonstrates that the established model is multiple fitted equation having a good reliability [START_REF] Zhou | Research On the Quality Evaluation Model of Mobile Information Service Based on the Consumer Satisfaction[END_REF].

Conclusions

All study above shows that two aspects will be paid more attention to during the building of cloud service platform:

(1) In the process of construction for information service system, these indexes such as service interactivity, service individuation, service professionalism, information vividness, information comprehensiveness and interface friendly, are important to influence information service quality.

(2) During the process of building for cloud service platform, these 7 indexes such as platform stabilization, platform compatibility, platform safety, platform adaptability, platform expansibility, software deployment simplicity and software operation shortcut should be fully considered.

  matrix, C is constant term.

Fig. 1 .

 1 Fig. 1. Result of R-mode clustering

Table 1

 1 Service quality evaluation index system of information platform for tea industry

		First index	Second index	After R-cluster
			Function comprehensiveness	X1
			Service interactivity	X2
		Platform	Operation convenience
		function	Service individuation	X4
	X1Service		Service professionalism Platform popularity Information accuracy	X5
	Quality Index System	Platform information	Information authority Information vividness Information comprehensiveness Content uniqueness Organization orderliness Information timeliness Retrieval convenience	X9 X10
	for		Retrieval effectiveness
	Tea		Interface friendly	X16
	Industry Information Platform	Platform design Platform framework	Design standardization Creativity uniqueness Column novelty Structure clarity Style unity Color coordination Platform stabilization Platform compatibility Platform safety Platform adaptability	X19 X22 X23 X24 X25 X26
			Platform expansibility	X27
		Platform efficiency	Software deployment simplicity Software operation shortcut Demand response timeliness	X28 X29

Table 2 .

 2 Related coefficient matrix

		X1	X2	X3	X4	X5	…	X30
	X1: Function comprehensiveness	1
	X2: Service interactivity	0.15	1
	X3: Operation convenience	0.12	0.14	1
	X4: Service individuation	0.11	0.32	0.18	1
	X5: Service professionalism	0.47	0.41	0.56	0.24	1
	X6: Platform popularity	0.12	0.13	0.68	0.05	0.87	…
	X7: Information accuracy	0.21	0.89	0.12	0.98	0.94	…
	X8: Information authority	0.45	0.86	0.11	0.84	0.92	…
	X9: Information vividness	0.13	0.97	0.13	0.86	0.94	…
	X10:Information comprehensiveness	0.97	0.75	0.08	0.88	0.96	…
	X11: Content uniqueness	0.12	0.85	0.14	0.99	0.92	…
	X12: Organization orderliness	0.65	0.82	0.84	0.15	0.87	…
	X13: Information timeliness	0.78	0.94	0.89	0.98	0.82	…
	X14: Retrieval convenience	0.56	0.93	0.97	0.97	0.84	…
	X15: Retrieval effectiveness	0.42	0.84	0.85	0.99	0.86	…
	X16: Interface friendly	0.01	0.95	0.89	0.85	0.12	…
	X17: Design standardization	0.75	0.12	0.84	0.12	0.98	…
	X18: Creativity uniqueness	0.15	0.78	0.12	0.86	0.12	…
	X19: Column novelty	0.12	0.86	0.11	0.87	0.15	…
	X20: Structure clarity	0.32	0.81	0.84	0.98	0.56	…
	X21: Style unity	0.15	0.14	0.91	0.15	0.86	…
	X22: Color coordination	0.11	0.23	0.56	0.12	0.14	…
	X23: Platform stabilization	0.12	0.45	0.98	0.11	0.86	…
	X24: Platform compatibility	0.11	0.21	0.94	0.15	0.14	…
	X25: Platform safety	0.11	0.12	0.12	0.12	0.86	…
	X26: Platform adaptability	0.92	0.15	0.84	0.87	0.84	…
	X27: Platform expansibility	0.95	0.34	0.23	0.56	0.85	…
	X28: Software deployment simplicity	0.87	0.87	0.86	0.87	0.85	…
	X29: Software operation shortcut	0.12	0.15	0.92	0.86	0.92	…
	X30: Demand response timeliness	0.23	0.97	0.76	0.82	0.85	…	1

  4, 11, 15, 7, 13, 20, 8, 18, 21; R 2 : 3, 23; R 3 : 5, 17; R 4 : 6, 10, 14, 30; R 5 : 1; R 6 : 2: R 7 : 9; R 8 : 12; R 9 : 24; R l0 : 28; R 11 : 19; R l2: 27; R 13 : 16; R 14 : 21; R 15 : 22; R 16 : 26; R 17 : 29.

	0.1
	0.09
	0.08
	0.07
	0.06
	0.05
	0.04
	0.03
	0.02
	0.01
	0
	4 11 15 7 13	20	8 18 21	3 23 5 17	6 10 14 30	1 2 9 12 24 28 19 27 16 21 22 26 29

Table 4 .

 4 Experimental data

	Y	X1	X2	X4	X5	X9	X10	X12	X16	X19	X22
	0.84	0.77	0.81	0.80	0.81	0.68	0.74	0.88	0.44	0.55	0.88
	0.39	0.77	0.36	0.35	0.37	0.25	0.29	0.88	0.04	0.16	0.88
	0.38	0.75	0.35	0.34	0.35	0.25	0.28	0.86	0.04	0.14	0.86
	0.60	0.74	0.61	0.56	0.56	0.52	0.50	0.88	0.21	0.32	0.88
	0.73	0.72	0.69	0.69	0.69	0.61	0.63	0.86	0.32	0.43	0.86
	0.35	0.71	0.31	0.31	0.31	0.22	0.25	0.82	0.03	0.13	0.82
	0.31	0.71	0.27	0.26	0.27	0.15	0.22	0.80	0.01	0.09	0.80
	0.74	0.71	0.71	0.70	0.71	0.62	0.65	0.84	0.34	0.44	0.84
	0.52	0.71	0.50	0.47	0.49	0.40	0.42	0.84	0.12	0.23	0.84
	0.85	0.70	0.82	0.82	0.82	0.68	0.75	0.80	0.45	0.56	0.80
	0.54	0.70	0.52	0.50	0.51	0.43	0.44	0.80	0.14	0.26	0.80
	0.48	0.70	0.47	0.44	0.45	0.35	0.37	0.80	0.09	0.19	0.80
	0.35	0.70	0.34	032	0.32	0.23	0.25	0.80	0.03	0.13	0.80
	0.31	0.69	0.27	0.27	0.27	0.14	0.21	0.78	0.01	0.08	0.78
	0.50	0.69	0.47	0.43	0.46	0.38	0.39	0.82	0.10	0.20	0.82

Table 5 .

 5 Relative errors between predicted and actual values

	Sequence number	True value	Predictive number	Relative error
	1	0.69	0.694392	0.64
	2	0.47	0.466296	1.63
	3	0.64	0.640351	0.05
	4	0.34	0.336517	1.60
	5	0.64	0.639849	0.02
	6	0.55	0.555037	0.44
	7	0.34	0.336832	2.31
	8	0.83	0.829506	0.54
	9	0.58	0.586938	1.90

Acknowledgment

Financial supports from the National Science and Technology Support Project of China (Grant No. 2013BAD15B05) and the Natural Science Foundation of Beijing, China (Grant No. 4151001) are sincerely acknowledged.

Website Professional(22) http://www.ymt360.com http://tea.fjsen.com http://www.teauo.com http://www.zgchawang.com http://www.i-tea.cn http://tea.ahnw.gov.cn http://cy.zgny.com.cn http://www.t0001.com http://www.teatea.co http://www.fjteaw.cn http://www.tea160.com http://www.chawh.net http://www.b-tea.com http://www.puercn.com http://www.hbteainfo.com http://www.qspg.cn http://www.cyppw.com http://www.bjhjcha.com http://www.cs12396.cn http://www.ctma.com.cn http://www.cluyu.cn http://www.paicw.com Comprehensive(18) http://bb.ahnw.gov.cn http://www.xinnong.com http://www.ynagri.gov.cn http://www.sbny.cn http://www.cnsp.org.cn http://www.tech-food.com http://www.cnluye.com http://www.farmers.org.cn http://www.yuanlin365.com http://www.8658.cn http://nc.mofcom.gov.cn http://video.1kejian.com http://www.scnjw.gov.cn http://www.xxsagri.gov.cn http://www.agronet.com.cn http://www.qzny.gov.cn http://www.eagric.com http://www.foodmate.net


Yanan Hu
email: huyanan05@hotmail.com

Yun Zhang
email: zhangyun@agri.gov.cn

Yanqing Duan
email: yanqing.duan@beds.ac.uk

Improving Agricultural Information and Knowledge Transfer in Cambodia -Adopting Chinese Experience in using Mobile Internet Technologies

Agriculture is a knowledge intensive sector. Information and knowledge plays an essential role in helping farmers to improve productivity and sustainabilitythroughpromoting and adopting the most effective and relevant innovations and technologies. With rapid development and advances in agriculturalscience and technology, traditional agriculture practices have been transformed to knowledge based and digital agriculture production. This paper reports a project that aims to improve the agricultural information and knowledge flow in Cambodia by adopting China's success in using Mobile Internet Technologies. The paper providesa brief reviewof China's current achievements in using ICTs to accelerate information and knowledge flow in Agriculture and Cambodia's current status in using ICT for agriculture information disseminations. An empirical investigation was carried out in Cambodia to gain more insights into the farmers information needs and their intention to adopt Mobile Internet based information dissemination services. Based on the empirical study, Chinese experience in using Mobile App was introduced and a mobile App called AgriAppwas designed and tailored to meet the Cambodia's needs and conditions. This AgriApp was initially tested and valuable feedback was collected for improvement and better deployment in Cambodia.

Introduction

The agriculture sector in Cambodia is the most important source of income. Cambodia's economy is still highly dependent on agriculture, which contributes close to one-third of national GDP and employs more than half of the total labour force [START_REF] Yu | Cambodia's agricultural strategy: Future development options for the rice sector[END_REF]. However, as a result of the rapidly changing socio-economic conditions since 1990, Cambodia agriculture sector faces many new challenges such as high population growth, embracing a market economy, nationwide food security and decreasing agricultural production conditions. These challenges are exacerbated by the limited access to agricultural knowledge and information in the rural areas. There are limited knowledge bases and appropriate approaches for information and knowledge transfer. As a result, the latest agricultural technology and market information cannot reach farmers in a timely manner. At the same time, farmers' problems and inquires cannot be addressed directly and timely. Therefore, it is imperative to improve Cambodia's agricultural productivity and economic situation of farmers through better information dissemination service.

Over the last three decades, China has been very successful in transforming its Agriculture sector through the effective deployment of Information and Communication Technologies (ICTs). Information processing and dissemination have played a critical role in this transformation process [START_REF] Zhang | Supporting Chinese Farmers with ICT-Based Information Services: An Analysis of Service Models[END_REF]. It is believed that sharing Chinese experience and best practice would help Cambodian's agriculture sector in utilising the latest ICTs to facilitate knowledge and information dissemination. This paper reports a research project that seeks to extract useful and practical Chinese experience, especially in the area of the applications of the latest mobile Internet and GIS technologies, and adapt it to the Cambodian context. The research focuses on analysing information needs, selecting information sources, developing knowledge and information repository, and designing and demonstrating technical tools and platforms for effective information dissemination. Theresearch project combines Chinese technologies for information sharing using smart phones with Cambodian data to promote effective and efficient agricultural information dissemination, so as to improve the knowledge and information dissemination flow in the rural area of Cambodia in the long run.

Review of agricultural information dissemination in China

This research reviews the current ICT-based information service models in China to develop a better understanding on how different ICT-based information service models are designed and adopted in China; and to share the knowledge and experience in applying emerging ICTs in disseminating agriculture information to farmers to improve productivity and economic, social and environmental sustainability.

Information services for farmers at the national and regional level are a promising new field of research and application in the emerging field of e-agriculture [START_REF] Gakuru | Innovative Farmer Advisory Services Using ICT[END_REF]. Information services play a critical role in modern agriculture and rural development and Information management and accessibility are at the core for information dissemination [START_REF] Li | China Rural Informatization Development 2010 Report[END_REF].To improve agriculture productivity, farmers have an ever increasing demand for information because accessing information and knowledge is essential for improving their productivity [START_REF] Zhang | Supporting Chinese Farmers with ICT-Based Information Services: An Analysis of Service Models[END_REF].Agricultural information can be effectively disseminated by television, radio, newspapers, Internet, mobile phone,Short Message Service (SMS), Mobile Internet APPs (3G, 4G smart phones and handhelds) orthecombinations of different channels.

With the development of information technology, the agriculture information service model is constantly evolved and improved. Based on extensive review of reports and literature (e.g. [START_REF] Li | China Rural Informatization Development 2009 Report[END_REF][START_REF] Li | China Rural Informatization Development 2010 Report[END_REF][START_REF] Liu | Reflections on the development of Agricultural Informatization[END_REF]; MOA Information Centre, 2014), the agricultural information service models in China are classified into the following types:

1. Web Portala collection of relevant web sites to form an one stop center for users, e.g. MOA Web Portal, etc. 2. Voice-Based Serviceinformation dissemination through telephone, i.e. call centers, e.g. Liaoning 12316 Golden Farming Hotline. 3. Text (SMS)-Based Serviceinformation dissemination through text message of mobile phones. This service is normally jointly operated by Agriculture sector and Telecom service providers, e.g Hunan Agri-Telecom Platform. 4. Self-Support Online Communityinformation services provided by a community to its members. This is a membership based system involving all stakeholders, members share experience and exchange information through interactive service platforms, e.g. farmers Mailbox in Zhejiang Province. 5. Interactive Video Conferencing Serviceusing online multimedia technology to facilitate information service, e.g Shanghai Farmers "One Click and Go" service, or Intelligent Farmers service. 6. Mobile Internet Based Serviceinformation dissemination through smart phone service, e.g. Agribusiness price information, E-news, etc. 7. Unified Multi-Channel Service Modelutilizing multiple methods to effectively disseminate information through telephones, computers, and mobile phones., e.g "3 in 1" service in Fujian

To select the most appropriate models, the information infrastructure, the operating costs, farmers' capabilities, farmers' information consumption behaviour and, most importantly, the local context should be taken into consideration [START_REF] Zhang | Formation Conditions and Development characteristics of Chinese Agricultural Information Service Model[END_REF].

The key impact of agriculture information services in China can be highlighted in the following areas [START_REF] Zhang | Supporting Chinese Farmers with ICT-Based Information Services: An Analysis of Service Models[END_REF]:

 Improved the efficiency of Agriculture Services, e.g. "12316 hotline", "Unified 3 in 1 service", etc.  Increased farmers' income  Improved agriculture productivity  Reduced the digital gap between rural areas and modern cities

Agricultural Information Dissemination in Cambodia

Agricultural sector plays a very important role in economic development of Cambodia. Hence, the Royal Government of Cambodia (RGC) has made a strong commitment to improve the country's agriculture sector after successfully leading the Cambodian economy out of the most difficult time of recent global financial crisis and economic downturn (CARDI, 2014). However, Cambodia is currently in urgent needs for developing adequate agricultural information dissemination services. For example, although effective market information systems in Cambodia can reduce information asymmetries, increase competitiveness, and improve marketing system efficiencies (EC-FAO, 2015),majority of farmers are still have no access the market information in a timely way. There is, therefore, strong demand for higher efficiency and effectiveness in agricultural information dissemination within Cambodian farming communities.

The Cambodian government has realised the importance of collecting, processing, managing and disseminating agricultural information and developed a series of initiatives to improve the situation.For example, Council of Agriculture and Rural Development (CARD) has established a single entry-point called the 'Cambodian Agricultural and Rural Development information Gateway' (CARDiG). The aim of CARDiG is to provide a portal for information sharing on agriculture and rural development and boost information and knowledge management among stakeholders through better access to web-based information.

Under the supervision of Ministry of Agriculture, Forestry and Fisheries (MAFF), ICT is widely used in government organisations at all levels to enhance the information flow to farmers and other stakeholders. MAFF has been implementing some projects working on improving productivity and market information of agricultural, such as providing all related information through radio broadcasting program, mobile SMS and websites. Besides that, MAFF has also formed many agricultural cooperatives at the rural community level and equip those communities with a set of desktop computer and other agricultural lessons CD.

Cambodian Agricultural Research and Development Institute (CARDI) has set up an agriculture-related electronic library, which includes various agricultural publications and research bulletins for online reading and download. Cambodia has also developed databases on agricultural subjects, such as soil, phytopathology and rice planting. Agricultural information is usually disseminated via radio, TV, mobile SMS and websites, providing effective guidance for agricultural production.

In summary, the main methods used in disseminating the agricultural information in Cambodia are shown in figure 1 (CARDI, 2014) which include:

Traditional face to face approaches -This approach disseminates information to farmers through field visit and demonstration, farmers field school and training, Agriculture forum, annual conference, monthly meetings, etc. This has been the most popular approach by farmers, but it is not the most effective and efficient method due to the financial and human resources involved.

Printed materials -Scientific and technical information was delivered to stakeholders through the periodical publication of research note, research bulletin, farmers' notes, project report, Journal of agriculture and other reading materials.

Mass media (TV and radio) -

Information is broadcasted to a large number of farmers at fix times. The survey and focus group feedback indicate that this was seen as a not very popular methods because of the inflexibility of fix programmes.

Internet and CD -CARDI and other relevant bodies also publish regular information and demonstration of new development in their website for key stakeholder, such as: agricultural extension agents and key farmers to obtain the latest news and development in agriculture sector. CDs are also produced and distributed to farmers and agents for information dissemination purposes. Though Network technology is relatively backward with low coverage,it is a fast growing area. Mobile phone penetration is significantly higher than landline. Currently, a total of 21 companies have the business license from Ministry of Posts and Telecommunications. There are eight mobile phone companies, two un-mobile phone companies, twenty eight network service companies, seven 3G service companies, 15 VOIP service companies and 16 VSAT service companies. It is predicated that Cambodian mobile phone users will up to 20 million, and mobile phone will become a communication tool widely used in daily life and work. In Cambodia, about 2.5 million people use Internet, accounting for 17.5% of the total population, so Cambodia has the policy environment, hardware and software to build the agricultural information service platform.

However, the review of current situation suggests that although Cambodia government have realised the importance and needs for improving agricultural information dissemination and developed a series initiative in recent year, there is still a huge gap for significant improvement. The current information dissemination patterns in Cambodia are all one-way communication and lack of interactivity. They often cannot solve the specific problems of farmers in a timely and effective way. The agricultural information technology infrastructure in Cambodia is quite dated. Information dissemination mainly uses traditional media, such as radio, television, and paper based publications, so the dissemination efficiency and coverage are greatly restricted. The latest agricultural policy from agricultural sector is mainly released top down in the form of telephone. The way to promote the agricultural technology is regularly to organize trainings for farmers, so only a few farmers can get the information, and the effectiveness and pertinence is poor. For example, majority of farmers still have little information and difficult to obtain timely and accurate market and buyer information, leading to agricultural products unmarketable or the sale price is much lower than average. Aimed at these problems above, Cambodia hopes to push the latest agricultural technology to farmers through the advanced mobile Internet technology and the GMS agriculture network platform.

In China, with the development of information technology, the agriculture information service models and operating patterns are constantly developed and enhanced. It is believed that Cambodia can benefit greatly from the Chinese experience and best practice if introduced and adapted effectively.

Understanding the information needs of Cambodia farmers -empirical investigations

To introduce China's success experience in agricultural information services and meet Cambodia farmers' needs and conditions, this research conducted a number of empirical investigations in Cambodia including surveys, focus groups and interviews with different stakeholders. The findings of the investigations help to gain in-depth insights into farmers' accessibility to information resources, their information needs and seeking behaviour, their intention of adopting ICT-based dissemination models, etc. The key findings also help to select the most suitable solutions for adapting Chinese information dissemination experiences using Mobile Internet technology.

Farmer survey on information dissemination and adoption intention of mobile device

A questionnaire of farmer survey was developed and translated into Khmer. It consisted of two main parts which were current situation and adoption intention questions. The part one of the survey covered the following areas:

1) Date and location of survey 2) Personal information 3) Farm information 4) What are the main problems in the current information dissemination? 5) Whom do you want to receive the information from? 6) How important do you believe to receive the following types of information to improve your farm productivity 7) Your preferred information delivery methods Part two of the survey concerned the adoption intention that collect farmers perceptions and intentions in the following areas:

1) Performance expectancy 2) Effort expectancy 3) Attitude toward using technology 4) Social influence 5) Facilitating conditions 6) Behavioural intention to use the system if the system is available The farmer survey was conducted in the two target pilot locations and a total of 95questionnaires were collected. During the surveys, group discussions and interviews with farmers, farmer managers and key farmers were also conducted to explore further their information dissemination needs and preferred dissemination channels.

At the end of farmers' surveys, some of participants expressed their appreciation saying that they were very pleased to be invited and the information and demonstration were very useful for them. It was an eye-opening experience for them.

The survey results indicate that the major problems are no necessary equipment to access the electronic information, having difficulties to find the information they need, notknowing where to find information, and no relevant information available. Farmers would like to receive all relevant information that can help them improve productivity and sell their products. The adoption intention is also high although most of farmers still don't have smart phones.

Workshop on upgrading Cambodian's agricultural information dissemination system

A workshop on upgrading Cambodian's Agricultural Information Dissemination System was conducted in Phnom Penh to share experiences regarding to agricultural information dissemination system in Cambodia and the successful experiences of ICT technologies, especially mobile internet technology in China. The outcomes of the workshop were also contributing to guide the project implementation. A total of 30 participants from different institutions andorganizations attended the workshop.

After introducing the Chinese current success in agricultural information dissemination using ICTs, the participants were divided into three groups to discuss: 1-Problem and challenge of ICT in Cambodia, 2 -Adoption of ICT based information dissemination technology in Cambodia, and 3 -What is the most needed information for farmers?.

The outcome of group discussions are summarised below:

The problems and challenges of ICT based information dissemination in Cambodia:

1. Most farmers lack of knowledge in utilization of internet 2. Extension documents are not widely used 3. Not availability of internet in the rural areas 4. Not accessibility electricity in remote areas 5. Insufficient IT equipment for accessing the Internet, e.g. PC, smart phones or tablets 6. Financial problem: the rural people couldn't afford to purchase computers or phones 7. Internet service charges are too costly 8. Low literacy level 9. Market information is not regularly and widely disseminated.

The most useful ICT based on information dissemination technology in Cambodia is:

1. Mobile phonee.g SMS 2. Mass Media -TV, Radio and Video 3. Tele-center -Extension Hub 4. E-library 5. Internet-websites, social media, ect.

The most needed information for the farmers are:

1. National and international market information 2. Techniques of improvement product. 3. Quality and safety products 4. Weather forecasting 5. Potential product 6. Geographical potential 7. Agriculture service providers Based on the empirical investigations, farmers have demonstrated strongest demand for the following five agricultural information services : Pest warning and control technology, agricultural price information, planting/farming technical guidance, new product and new agricultural policy.

The most important findings of the empirical investigations is the need to have information and knowledge brokers as an intermediary between information providers and farmers. Therefore, the main information users for piloting the mobile Internet based information dissemination system in the project are be the key farmers in villages and farm commune centres who have sufficient education qualifications and IT skills to understand and absorb the information and knowledge. They will then communicate the information and ideas to local farmers as an information and knowledge broker.

The content to be disseminated to farmers should be easy to understand. The field investigation analysis has suggested that farmers would like to see the information being presented using video, audio, image, simple and short text messages. The initial piloting materials can be based on the most popular paper based materials, such as farmers' notes and bulletins. Other potential piloting information would be based on the current available information resources and knowledge repository, such as the selection of the new rice varieties and use of fertilisers because farmers are very keen to adopt the new varieties and technologies to improve the rice productivity.

Adopting Chinese experience and development of AgriApp

To share the China'success story, thisresearch project introduced China's experience and best practice in disseminating agricultural information to the vast number of farmers using ICTs in the project workshop. The presentation and demonstration in the workshop included Chinese agricultural information service models, latest development, hotline 12316, Hunan Nongxintong SMS, Nonghuibao App, Fujian 3-in-1 integrated service platform, etc. The Cambodian Agricultural representatives were very keen to learn from Chinese advanced agricultural information technology and development models. They strongly believed that conducting the agricultural information service pilot project under the GMS agriculture network platform can help Cambodia to develop the agricultural information services and improve the agricultural productivity.

The project team also conducted live demonstrations to farmers during the field trips to show how farmers in China can access important agricultural information and make online inquires via mobile Internet. Farmers were fascinated by the demonstration although most of them may not be able to benefit from this type of dissemination model directly in the near future due to their low lever education and computer literacy. Based on the field investigations, China's experience, and the technical expertise of the project partners, the dissemination platform and prototype App called AgriApp were developed.The system consists of two parts: the agricultural information database management system in server-side and the agricultural information service application in mobile-side.

The mobile side is an Android program that currently have three main functions: 1. Agricultural information dissemination that is designed to show all the agricultural information in different categories; Agricultural information search that allows the users to use the search function to query the information based on their interest and needs; 3. Agricultural information inquiry that allow the users to submit the problems that they encounter in their farming activities by using text description and images, so the system can provide relevant answer based on its knowledge base and users' location. User questions will be transferred to the server side along with the geographic location information to better help the administrators identify where these farmers are and provide more accurate and effective feedback.

The server side is developed to enable the management of messages from the mobile users (see sample screenshots in figure 3). The administrator also can edit and post his/her own message, such as some useful agricultural info and disaster alerts to the end users through this server application. More importantly, the server program can use a GIS map engine to display the locations of all message senders, thus to help the administrators to better address end users' inquires. This is very useful for future scientific analysis.

Figure 3.Sample screenshots of AgriApp

The agricultural information database management system provides data management functions to the administrator, such as data entry, data display, data modification, and data deletion (see the sample screenshots in figure 4). It has three main functions: 1. information content management, 2. user inquiry management, and 3. information display management. While the agricultural information service application provides farmers with three main functions, like agricultural information display, query/question consultation, etc. This type of information platform enables two-way communications of agricultural information between farmers and the information systems including expert team in the background, which forms an effective mechanism among information sharing and dissemination, and achieves sustainable development of the platform. The prototype AgriApp was initially tested for its suitability in Cambodia. Project team visited Cambodia for on-site system deployment, training, and promotion. Over 30 Cambodian agricultural officials and farmers were invited to participate in the training. The project team introduced the AgriApp and provided the step-by-step demonstration on the use of theApp to ensure that all participants were fully familiar with its application.

All stakeholders participated in the training workshop discussed the issues on how to effectively promote the system in Cambodia to fully benefit the farmers. The project team invited a number of local farmers to try the App on their phones. The farmers were impressed by the useful functions after going through them with the technical assistance. They showed their interest to continue using the AgriApp to better help their farming activities.

The senior officers in Cambodia governmentalso showed their interest in promoting AgreiApp and pointed out that this new technology represents the future trend for the agricultural information dissemination and has great advantages over traditional dissemination approaches, e.g. call centre, SMS, with regard to the interactivity and costs. They stressed that this new dissemination model should be promoted widely in Cambodia.

Conclusion

The research reported in this paper aims to improve agricultural information dissemination in Cambodia by adapting China's experience in using Mobile Internet Technologies. To achieve this aim, the research first conducted a comprehensive review on agricultural information service models in China and their suitability for Cambodia. A number of empirical investigations on the current information provision and farmers' information needs and technology adoption intention are examined through surveys, interviews and focus groups. A prototype AgriApp is developed and tested in Cambodia and has received very positive feedback from key stakeholder. The key novelty of AgriAPP is the use of comprehensive knowledge base and the advanced GPS technologies to locate users and to provide tailor made advice suitable to the specific needs of the user. The improved App tools will be developed in the future for wider adoptions.

To improve the agricultural information and knowledge transfer in Cambodia, this research identifies two major issues to be addressed: one is to meet the farmers' urgent needs of information services; and the second is to improve the current ICT infrastructure andthe outdated and ineffective information management and service methods that are not taking advantages of emerging ICTs. The mechanisms for developing effective ICT-based information dissemination models should be government-led, centralized services and market-oriented operations. Based on mobile Internet and GIS technology, the comprehensive agricultural information service platform, incorporating voice, network and mobile terminal, is an important direction for Cambodian agricultural information dissemination and mobile service applications. This interactive multi-channel service model can effectively transfer much needed information to farmers so as to improve their skills and productivity. In addition, this service model is also cost effective and needs low system maintenance and facilitate better communications.

It is believed that the experience and findings from this research provide a useful direction for researchers and practitioners in developing future ICT based information processing and dissemination systems and will help other developing countries to learn from China's experience and best practice in their endeavour of applying emerging ICTs in agriculture information dissemination and sharing. Future research will be carried out to further improve the data sources and functionalities of the AgriApp. More field tests will also be conducted with various users, especially agriculture extentionists, to understand its potential effectiveness and impact.

Figure 1 .

 1 Figure 1. Cambodia agricultural information dissemination methods (CARDI, 2014)

Figure 2 .

 2 Figure 2. Field demonstration

Figure 4 .

 4 Figure 4. Sample screenshots of AgriApp content management system

Acknowledgement

The work reported in this paper is part of a research project on prompting agricultural knowledge and information flows. The authors would like to acknowledge the financial support provided by the Agricultural Technology Transfer (AgriTT) programme which is funded by UK Department for International Development (DFID). Project partners, Supermap in China, was responsible for design and development ofAgriApp for the project, and, CARDI in Cambodia, provided valuable background information and assisted the Cambodian field investigation and training workshops. The authors are very grateful for their important contributions.