Eija Koskivaara
email: eija.koskivaara@utu.fi

Improving Physical Activity and Health with Information Technology

Keywords: physical inactivity, activity monitoring, improvements in health and wellbeing

. Regular physical activity (PA) such as walking, cycling, or participating in sports has significant benefits for health and weight-loss maintenance. It reduces of the risk of diseases, e.g. diabetes, depression, or helps weight controlling. This one year case study explores how daily monitoring of objective PA and weight effects on body mass index (BMI) -value when the target is to achieve globally accepted normal BMI-value. The study aims to learn by costeffective modelling how improvements in wellbeing and health on an individual level occur with the help of information technology gadgets.

Introduction

World Health Organization (WHO) has reported physical inactivity as the fourth leading risk factor for global mortality causing an estimated 3.2 million deaths globally. Indeed the number of deaths per year increases to six million when also overweight and obesity are counted together with physical inactivity [START_REF] Who | Global Strategy on Diet, Physical Activity and Health[END_REF]. This is a tremendous figure -especially -as it is mostly related to our living habits.

Regular physical activity (PA) such as walking, cycling, or participating in sports has significant benefits for health and weight-loss maintenance [START_REF] Ekelund | Physical activity and gain in abdominal adiposity and body weight: prospective cohort study in 288,498 men and women[END_REF]. Although, the nature between objectively measured of physical activity and abdominal fat distribution has not been well characterized [START_REF] Philipsen | Associations of Objectively Measured Physical Activity and Abdominal Fat Distribution[END_REF], previous studies have firmly shown that PA reduces of the risk of diseases and reduce mortality and extend life expectancy [START_REF] Vanhees | Importance of characteristics and mo-dalities of physical activity and exercise in the management of cardiovascular health in individuals with cardiovascular risk factors: recommendations from the EACPR. Part II[END_REF][START_REF] Wen | Minimum amount of physical activity for reduced mortality and extended life expectancy: a prospective cohort study[END_REF]. But the challenge is: How do we change our way of living? How can we be more physical active in modern information society? Indeed, we need to find practical solutions how this is possible to do with the help of ICT gadgets.

To be more active is challenging as at the same time there are several new attractive leisure time thefts such as Angry Birds, Facebook, You Tube, Play Stations, Wiis, and virtual games on internet. As technology devices and services are penetrating the society into deeper levels, the need for studying their usefulness for physical activity and wellness becomes imperative. Modern technology and popularization of internet has brought a variety of applications aiming at promoting personal health and wellness available for layman, such as pedometers, heart rate monitors, and multidimensional accelometers.

The PA is a well-studied field within healthcare research internationally. We have reviewed literature and found around two hundred research journals where technology have been used for improving the individual ability to get encouraged for achieving recommended levels of exercise and physical activity [START_REF] Locke | Expected values for pedometer-determined physical activity in older populations[END_REF]. However, in most of these research articles the research design and sample is based on treatment of some disease. In order to increase the physical activity of population we need to understand how normal layman use information and communication technology (ICT) devices to support their physical activity and to improve their health and wellbeing.

In this one year case study our focus is on exploring how daily monitoring of PA, physical exercise (PE) and weight (WE) effects on Body Mass Index (BMI) -value. The BMI is commonly used to classify underweight, overweight and obesity in adults. It is a simple index of weight-for-height. The BMI is defined as the weight in kilograms divided by the square of the height in meters (kg/m2). The international classification of adult BMI for normal range is from 18.50 to 24.99. The wellbeing target of the current study is to achieved globally accepted normal BMI (body mass index)value. The assumption is that with the normal range BMI value the life time expectancy is superior and quality of live is better than with overweight situations: i.e. health and wellbeing of an individual improves when BMI value of overweight/obese decreases.

The primary contribution of the study presents how information and communications devices and the data they provide can be used to improve our everyday health. In our study model we use this data to support achieving normal BMI value. The success of the model is judged based on achieved BMI target.

The structure of the paper is organized as follows. Section two focuses on research background: 1) the use of information and communication technology (ICT) for health and well-being, and 2) global trends behind the study. In section three the research design is described. The results are presented in section four. Conclusions and research limitations as well as the future research directions end the papers.

Research background

ICT used in or proposed to use for improve health

ICT has been proposed to improve health in many ways and in different levels but there are communication and integration challenges. Analysis of big data on population level is one approach. Electronic health records could improve population health by including better understanding of the level and distribution of disease, function, and well-being within populations [START_REF] Friedman | Electronic health records and US public health: current realities and future promise[END_REF]. When an individual get access to his or her own data electronic health records it can be called personal health record which enables patients to access their health information and improves care quality by supporting self-care [START_REF] Ahmadi | A review of the personal health records in selected countries and Iran[END_REF]. However, then personal health records need to be integrated with physicians' electronic health records systems and provide shared access both ways in addition to secure e-mail communication and educational modules [START_REF] Johansen | The Evolution of Personal Health Records and their Role for Self--Management: A Literature Review[END_REF].

Delivering health related data via internet and establish kiosk and centers have worked very well in developing countries [START_REF] Joshi | Using Portable Health Information Kiosk to assess chronic disease burden in remote settings[END_REF][START_REF] Zakar | Harnessing information technology to improve women's health information: evidence from Pakistan[END_REF]. However, delivering healthcare information totally freely, for example via You Tube, requires to design some kind of interventions to enable consumers to critically assimilate the information with more authoritative information sources to make effective healthcare decisions [START_REF] Madathil | Healthcare information on YouTube: A systematic review[END_REF].

On the other hand, implementations of new information systems have faced difficulties, especially when it changes dramatically the well-established business models in the field. For example, in Europe implementations of electronic prescriptions have taken more time than expected [START_REF] Hammar | Implementation of information systems at pharmacies --A case study from the re--regulated pharmacy market in Sweden[END_REF][START_REF] Mäkinen | Electronic prescriptions are slowly spreading in the European Union[END_REF].

On individual level there has been several approached on using technology to health conditions. A systematic literature review of mobile health technologies reveal that they have potential to be used as tools for the prevention and treatment of overweight and obesity, particularly with mobile phones and texting, which are already used daily by most of the population [START_REF] Sarno | Mobile health and excess weight: a system-atic review[END_REF]. Based on another systematic review, there is an argument that despite the bold promise of mHealth to improve health care, much remains unknown about whether and how this will be fulfilled [START_REF] Peiris | Use of mHealth Systems and Tools for Non--Communicable Diseases in Low-- and Middle--Income Countries: a Sys-tematic Review[END_REF]. Electronic lifestyle activity monitors are commercially popular and show promise for use in public health interventions and provide feedback via an app in computer or mobile [START_REF] Lyons | Behavior change techniques implemented in electronic lifestyle activity monitors: a systematic content analysis[END_REF].

Using the PA devices provides more precise data than a subjective self-assessment. The use and feasibility of physical activity promoting websites and applications have been studied with encouraging results [START_REF] Vandelanotte | Examining the use of evidence--based and social media supported tools in freely accessible physical activity intervention websites[END_REF][START_REF] Ayubi | A Persuasive and Social mHealth Application for Physical Activity: A Usability and Feasibility Study[END_REF]. However, little is known about how objective physical activity assessment on 24/7 basis effects health. In this study, we observe objective PA assessment together with self-reporting PE, WE, and measure the success, i.e. health effects, of the project with the change of the BMI value. The feasibility of high intensity PA value was confirmed with self-assessment dairy of physical exercise. The study aims to model a cost-effective way for improving wellbeing and health on individual level without any communications or integrations to health professionals.

Global trends in world health

There are convincing evidence that a sedentary and unfit way of living increase the risk of numerous chronic diseases and conditions and even decreases longevity [START_REF] Who | GLOBAL HEALTH RISKS Mortality and burden of disease attributable to selected major risks[END_REF].

A physical inactivity has been one of the highest leading global risks for mortality in the world already for some time [START_REF] Who | GLOBAL HEALTH RISKS Mortality and burden of disease attributable to selected major risks[END_REF]. Physical activity is defined as any bodily movement produced by skeletal muscles that require energy expenditure. Physical inactivity causes an estimated 3.2 million deaths globally [START_REF] Who | Global Strategy on Diet, Physical Activity and Health[END_REF].

Overweight and obesity are defined as abnormal or excessive fat accumulation that presents a risk to health. A crude population measure of obesity is the body mass index (BMI), a person's weight (in kilograms) divided by the square of his or her height (in meters). A person with a BMI of 30 or more is generally considered obese. A person with a BMI equal to or more than 25 is considered overweight. Obesity has reached epidemic proportions globally, with at least 2.8 million people dying each year as a result of being overweight or obese [START_REF] Who | Global Strategy on Diet, Physical Activity and Health[END_REF].

The physical inactivity and obesity are modern rising risk factors and they can be found in everywhere, i.e. in high, middle and low income countries. Together they kill about 6 million persons per year. In order to avoid this, WHO has been launching "Global Strategy on Diet, Physical Activity and Health".

Being physically active is a major contributor for both physical and mental wellbe-ing [START_REF] Das | Rethinking our approach to physical activity[END_REF]. PA has many scientifically proven health enhancing effects and the PA is extremely effective in preventing and treating just lifestyle connected diseases. Stud-ies also confirm that long term physical activity e.g. walking is associated with signif-icant better cognitive function and reduced risk of dementia [START_REF]Walking and dementia in physically capable elderly men[END_REF][START_REF] Weuve | Physical activity, including walking, and cognitive function in older women[END_REF]. A major goal for public health is to identify evidence--based interventions to promote PA in popula-tions [START_REF] Pratt | The implications of megatrends in information and communication technology and transportation for changes in global physical activity[END_REF]. This includes research on how ICT could be used to promote PA in our everyday life.

Current global PA guidelines given by WHO for adults accumulate at least 150 minutes of moderate--intensity aerobic physical activity throughout the week or at least 75 minutes of vigorous--intensity aerobic PA throughout the week or an equiva-lent combination of moderate--and vigorous--intensity activity [START_REF]Physical Activity and Adults. Recommended levels of physical activity for adults aged 18 --64 years[END_REF]. The duration of PA should be at least 10 minutes per time. And one should involve at least two or more muscle--strengthening activities per week. Globally, around 31% of adults were insufficiently PA in 2008 according to Global Health Observatory of WHO. The lack of PA has effect on public health as there is evidence that inactive individuals have higher risks for many lifestyle diseases such as coronary heart disease, high blood pressure, stroke, type 2 diabetes, metabolic syndrome, colon and breast cancer, and depression. These risks could be significantly reduced with preventive behaviors, such as improving nutrition and enhancing in regular PA [START_REF] Warburton | Health benefits of physical activity: the evidence[END_REF].

In many countries the PA has been promoted by recommendations. The PA rec-ommendations differ from country to country, although the recommendations for adults of WHO are probably most well--known. Many persons want to be more physi-cally active, but achieving sustainable changes in lifestyles can be challenging and behavior determinants differ based on individuals and environments [START_REF] Sherwood | The behavioral determinants of exercise: implica-tions for physical activity interventions[END_REF]. Despite many benefits of the PA, initiation and maintenance rates in the general population have been rather disappointing [START_REF] Estabrooks | Physical activity promotion through primary care[END_REF]. And based on the resent figures we still need methods and implementation of successful PA interventions.

ICT--embedded health and wellness services have suggest empowering people to manage their health [START_REF] Anita | Rethinking health: ICT--enabled services to empower people to manage their health[END_REF]. Indeed, research evidence suggests that individuals who exercise are more likely to maintain weight losses [START_REF] Baker | Physical activity and maintenance of weight loss: physiological and psychological mechanisms[END_REF].

Monitoring of physical activity and weight during the study

The ICT has penetrated into our lives to a level where it has started to show as an integrated part of our bodies and ways of living. It has reshaped our habits. However, information and communication technology along with effective decision making combining motivational and environmental factors, can definitely improve our health level. One of the major contributing parts of physical activity is technology tools and services, such as: pedometer, accelerometer, heart rate monitor, social networking, sport gaming and devices, computer based counseling system, global positioning technology, mobile entertainment electronics. In this study, we are more interested in use and awareness of activity monitoring tool.

Activity monitors provide a means to examine the intensity, frequency, and duration of PA. The knowledge of daily activity may motivate some of us to be more active. The purpose of this study is to analyze and compare the change of PA per day by using Polar Active [START_REF] Brugniaux | Polar Activity Watch 200: a new device to accurately assess energy expenditure[END_REF] activity monitor for one year study period. Polar Active was chosen for this study because of its features. For example, it measures activity 24/7, it divides activity to different zones, and it contains daily activity target feature. The technology for the target calculations was the most important feature for selecting Polar Active. Primary, Polar Active has been developed for Physical Education purposes of students: The tacit educational aspect is, indeed, one of the issues in this study context: Are we able to change our living habits with the help of technology? Are we able to improve our wellbeing or health by using technology daily to support our change of living habits?

Polar activity technology detects and filters activity intensity, and calculates it to MET (Metabolic Equivalent of Task, or simply metabolic equivalent, a physiological measure expressing the energy cost of physical activities) values. In Polar activity technology METs are used to accumulate time in the five different activity zones: very easy (1-2 MET), easy (2-3.5 MET), moderate (3.5-5 MET), vigorous (5-8 MET), and vigorous+ (>8 MET) (Table 1 1.

Activity zones, MET values, and zones that add up active time in Polar Active. The calculation of active time (≥3.5 MET) has been patented by Polar. Active time is the sum of the times spent in the 3 upper zones. In this case study, we are interested in this MET over 3.5 values per day. Indeed, the data can be downloaded to appropriate Polar web service where the activity zones and also sleeping time will be visualized. In the web service, also sleeping time or more accurately time in bed can be calculated.

In Polar activity monitors (Polar Active, FA20, AW200), one dimensional (1D) acceleration is measured. When comparing 1D to 3D measurement in accelerometers in general, it has been shown that 3D does not significantly improve the prediction of energy expenditure compared to 1D [START_REF] Brugniaux | Polar Activity Watch 200: a new device to accurately assess energy expenditure[END_REF]. In Polar devices, 1D also provides longer battery lifetime.

The data is analyzed in 30 s epochs, and all epochs above 3.5 MET accumulate active time. Typical activity for moderate 3.5-5 MET zone is brisk walking. For vigorous 5-8 MET zone typical is playing and games e.g. playground games and rope jumping. Basketball, football and soccer usually are 7-8 METs. Typical vigorous+ activity is running fast. Sedentary activities (e.g. screen time) accumulate very easy zone. All the features and calculations of the monitor apply to all age groups from children to adolescents to adults.

Activity is counted in METs that express energy expenditure and are multiples of resting metabolic rate (1 MET=BMR). Calories are expressed as total kilocalories summing the daily activity calories and the user's basic metabolic rate through day and night. Steps are accumulated when activity is detected when cadence exceeds 70 steps per minute.

The acceleration based measurement does not measure accurately all activity modes. For example cycling, indoor cycling, weight training (gym) and 'light' aerobics do not give accurate METs, calories or steps.

Plus the activity values given by Polar activity monitor, the daily physical activity or actually physical exercise (PE) was also traced by minutes with watch. They daily weight was measured with Omron Body Composition Monitor BF500 at the same time of day with the same clothing, i.e. every morning before breakfast.

All the daily values were collected to the metadata file for further analyses from one year trim down case study of overweight middle-aged blue-collar woman. Data is gathered and analyzed based on daily PA (>3.5 MET, Polar Active) and physical exercise (PE) in minutes, and morning weight (kg). The PA and PE counselling was similar: avoid two successive days of non-PA/PE. The day was non-PA if the value was below 60 minutes. The trim down target was set to -1 kg/month.

Results

In 87 days PA was below one hour in two or more successive days (24 %). In 96 days there was no PE in two or more successive days (26 %). In 60 days both these values were below the target (16 %). In 115 days the morning weight was not measured because of work or holiday (32 %). The correlation between the change of weight and PA (-0.0343857) was higher than the correlation between the change of weight and PE (-0.01237). BMI-value decreased (29.0 -> 26.7), but is still 1.8 above normal value. Trim down project was 50 % successful (-6kg/12kg). Figure 1 shows daily PE and PA. Figure 2 shows change of weight during the study time.

Conclusions, research limitations and future research directions

Physical inactivity and obesity are leading global risks for mortality in the world. One of the major contributors for increasing the physical activity and decreasing obesity could be information and communication technology tools and services. This case study tried to develop an easy and implementable but effective ICT supported counselling interaction program for PA supported weight controlling program. This is important both for society and individuals. We all need urgently new approaches and tools to reshape our habits or create new ones in a rapidly changing world. Actually, we need different kind of solutions for keeping our daily PA on recommended level. In some cases we need education and training to understand what the PA recommendations are and how they are reached or how to use ICT tools to improve our health and fitness.

For investigating and understanding this phenomenon we have created a Step-Shape -project. This case study is one part of the project where we try to understand and learn the effects of IT use on health and fitness goals. This is a concreate, practical context and individual depending knowledge and therefore case study approach suits for it by giving us a possibility to learn something new.

The study was successful in a way that at least partially health and wellbeing improvements were achieved. However we may always ask whether it was the commitment to the program that provided improvements in the results, not the use of IT. But on the other hand we can also ask vice versa, whether it was the use of IT that provides improvements in the results, not the commitment for the projects. Therefore, we plan to continue the Step Shape project and this longitudinal case study and try to explore whether there are any sustainable changes in living habits.

However, whether the results of this particular case study can be transferred to similar situations are open. It is the reader, not the researcher, who determines what can apply to his or her context.

Figure 1 .

 1 Figure 1. Daily PE and PA

Acknowledgements

The author wants to tank Docent and Director of Sports Science Collaboration, Dr. Raija Laukkanen University of Oulu and Polar Electro Oy for support and encouragement during the project. The author also wants to thank the anonymous reviewers of the paper for the constructive feedback.


Olli Sjöblom
email: oljusj@utu.fi

Data Mining Challenges in the Management of Aviation Safety

Keywords: Management, Flight Safety, Strategic Management, Data Mining, Text Mining, Analysis Method

This paper introduces aviation safety data analysis as an important application area for data mining. Safety is a key strategic management concern for safety-critical industries and management needs new, more efficient tools and methods for more effective management routines. The aviation field is confronted with increasing challenges to provide safe and fluent services. Air travel has grown steadily during the last decades with a direct impact on the air traffic control. At the same time, the competition has become tougher because of increasing fuel prices and growing demand for air travel.

Introduction

Organisational decision making, especially in safety-critical systems, such as nuclear power and air traffic, is a complicated task. For successful operations, an acceptable air safety record has been required from the airline [START_REF] Liou | Building an effective safety management system for airlines[END_REF]. Air traffic has generally been forecasted to grow 5 -6 % annually over the next two decades [START_REF] Netjasov | A review of research on risk and safety modelling in civil aviation[END_REF], or even over the next 10 -15 years, the global air travel will probably double [START_REF]Analysis: The Airline Industry[END_REF]. Consequently, the number of accidents will respectively increase if nothing were done to improve it, which development would, clearly, be unacceptable. This is why new and efficient ways for improving air safety need to be explored [START_REF]European Commission, Proposal for a DIRECTIVE OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL[END_REF]. The conventional safety tools and methods based on data collection have reached their peak performance because of their inability to create new knowledge. Usually, data accumulates faster than it can be processed [START_REF] Wang | LSSVM with Fuzzy Pre-processing Model Based Aero Engine Data Mining Technology[END_REF]. For further improvements new methods and tools are urgently needed [START_REF] Evans | Development and initial validation of an Aviation Safety Climate Scale[END_REF].

Management in safety-related context

Any system can be recognised to consist of elements, or factors, or parts that make up the whole [START_REF] Barnard | The Functions of the Executive[END_REF]. Managing the organisation is exercised largely through management processes, in which the means of managerial communication inter-links with the environment. [START_REF] Johnsen | Managing the Managerial Process[END_REF] defines the management process as "the interaction between people who want to attain mutual ends through mutual means." [START_REF] Johnsen | Managing the Managerial Process[END_REF]. The strategy of the corporation is according to Johnson et al. [START_REF] Johnson | Exploring Corporate Strategy[END_REF] to concern the organisation's mission, vision and objectives, developing plans and policies to use resources for enhancing the performance of the organisation. Kettunen et al. [START_REF] Kettunen | Safety management challenges and tensions in the European nuclear power industry[END_REF] emphasise the managerial challenges in the safety-critical industries, which are typically related to finding a balance between diverging demands and expectations, like economy-and safety-related objects without forgetting the priorities-setting and maintaining focus on these components. The key action is a continuous balancing between taking risks and allocating resources for risk management. A scale with theoretical ends can be displayed, where at one end there is a situation where risks do not exist because the resources allocated are infinite; at the other end no resources are allocated because the risks are ignored and thus they are (practically) infinite. The reality is found somewhere in between, but no fixed location can be defined because all environments are somewhat unique and are also changing all the time. In daily operations perhaps existing hidden threats produce the need to maintain extra safety level naturally causing additional costs.

In studying risk management, the concept of tension cannot be ignored. It refers to the challenges of balancing conflicting objectives or expectations, like safety and other goals. These might exist for various reasons, even in the situation in which the executives of the organisation have set a high safety level as the priority official goal [START_REF] Sagan | The limits of safety. Organizations, accidents, and nuclear weapons[END_REF].In case warning signals appear, responding to those should happen without delay allocating safety resources to the critical area.

The safety decisions in an air traffic company follow the same pattern as other strategic decisions. Risk management should be carried out in parallel with safety management, referring to measures seeking to identify, assess and control risks on the organisational level having the goal to ensure the organisational and environmental safety. The executive management is responsible for recognising the safety significance of the ways the organisation is operated and maintained [START_REF]State-of-the-art report on systematic approaches to safety management[END_REF]. Managing risk and safety has been problematic in air transport: very high levels of safety are too costly -high levels of risk are unacceptable. Therefore, safety reports have been collected through decades to investigate and assess risks and to define risk standards, which are consistent with the value systems of the society [START_REF] Janic | An assessment of risk and safety in civil aviation[END_REF][START_REF] Sage | Methodologies for Risk and Hazard Assessment: A Survey and Status Report[END_REF].

The value of safety cannot be estimated in any traditional way, because it has no determined price. Theoretically, limitless resources should be allocated to it, because one single failure may lead to significant losses in the form of missed business possibilities and claims for covering the damage caused to a third party. Kaplanski and Haim [START_REF] Kaplanski | Sentiment and stock prices: The case of aviation disasters[END_REF] have presented some estimates for the accident costs. A very large disaster with hundreds of casualties will cause a loss of about $1 billion for an airline company. However, the observed market effect has been found to be about 60 times larger; Kaplanski and Haim (2010) have found the evidence of a significant negative effect with an average market loss of more than $60 billion per aviation disaster. However, budget constraints set limits in practise and therefore a certain risk has to be accepted by achieving a sufficient safety level. There is never a 0-level risk. In case sufficient resources could not be allocated to achieve the required level of safety, the whole air traffic business would be critical. When confronting such a situation, the operations are to be adjusted by diminishing or changing them to correspond with the allocable safety resources so that a sufficient safety level is maintained.

Estimating the significance and importance of different alternatives in managing risks also needs tools, the exact definition of which is important for making strategic decisions. After the executive management has set goals as the thresholds of achievement, there must be methods and models to measure to what degree the achievements have been realised. In the decision process, there is always question about evaluating different alternatives. Any matter having significance enough to be taken into account in the evaluation process should be considered for evaluation [START_REF] Kirkwood | Strategic Decision Making[END_REF]. Rumsfeld [START_REF] Rumsfeld | News Transcript[END_REF] has defined (simply expressed) three categories for knowledge: first, we know what we do know; second, we know what we do not know; and, finally, we do not know what we do not know. The hidden dangers belong to the last group, so in case we know what we are searching for, we obviously have means to reach it, but otherwise we need tools for finding something we do not know we are looking for. Thus, a deeper understanding is required for developing better methods and refining rules and practices that will contribute to higher levels of safety.

The unknown lethal factors brought into daylight could be eliminated; at least a significant part of them and a sufficient safety level could be reached with reduced investment allocation. For air traffic, there is theoretically no upper limit to allocate resources to safety in different forms. The relation between safety and cost efficiency could be illustrated explicitly comparing the costs between comprehensive maintenance programs and maintenance-induced accidents, the benefits that outweigh the accident costs [START_REF] Castro | A Holistic Approach to Aviation Safety[END_REF]. The process for allocating extra resources to special projects might become even more troublesome in case there are interdependencies among the projects [START_REF] Kirkwood | Strategic Decision Making[END_REF].

Flight Safety

According to the ICAO Safety Management manual [19], safety is defined as "a state in which the risk of harm to persons or property damage is reduced to, and maintained at or below, an acceptable level through a continuing process of hazard identification and risk management". Safety is not a matter-of-course, but the result of a rather complicated, carefully structured and comprehensive management process approaching to all airline safety aspects, particularly those of flight operations. Air traffic is full of incidents and deviations that do not contain any hazard as such, but need to be reported and investigated to find out potential lethal trends. These undesirable, but very minor events are valuable investigation subjects for risk and safety specialists to build an understanding about their causes and to detect unsafe trends. Investigation also reveals whether countermeasures are warranted and how to reduce or eliminate potential accidents [START_REF] Kirwan | Incident reduction and risk migration[END_REF]. The appearance of similar recurring cases (a cluster, cf. Chapter 6) may indicate a hazardous trend that should be analysed very carefully to find out whether a real danger exists or not. The possibly existing lethal trends are trying to penetrate through the layers of defences, barriers and safeguards (cf. Figure 1) that, fortunately, usually stop them from proceeding. Because serious incidents and even accidents do happen, it can be presumed that after a certain amount of time they pass all the layers but the last one; then they will pass the last layer as well, which leads to accidents.

Finding trends from flight safety data, especially from narrative data has required significant human involvement. Thus, the analysis process and its possible results rely on the skill, memory and experience of the safety officers [START_REF] Nazeri | Application of Aviation Safety Data Mining Workbench at American Airlines. Proof-of-Concept Demonstration of Data and Text Mining[END_REF]. Watson [22] found that with conventional techniques it might take years to find meaningful relationships. Before text mining systems (one sub-class of data mining) were developed, there were no tools for analysing textual data with computers. Data mining provides a worthy analysis method in order to illustrate the safety indicators and to reveal undesired trends.

Safety Tools and Systems

Accident analysis as well as flight and operations modelling and simulation enhance the understanding of risk, but this is usually reactive and produces knowledge about causal factors potentially at the human and/or financial cost. Risk modelling typically collects knowledge resulting from flight safety analysis, human experience and theoretical and empirical studies. The goal of aviation risk assessment is to be comprehensive, timely and proactive, and this is why the analysis methods should be enhanced [START_REF] Hadjimichael | A fuzzy expert system for aviation risk assessment[END_REF].

In aviation, the quantitative assessment of risk is particularly challenging, because the deviation events are extremely rare and the causal factors are non-linearly related to the events which makes them difficult to quantify [START_REF] Hadjimichael | A fuzzy expert system for aviation risk assessment[END_REF]. The eventuality for the incident or accident occurring may be markedly reduced in case the risks can be efficiently diagnosed [START_REF] Lee | Risk assessment modeling in aviation safety management[END_REF]. Then the question is: how to find and identify deviations leading to incidents and those leading to accidents? Reason [START_REF] Reason | Managing the Risks of Organizational Accidents[END_REF] has modelled the process for the occurrence of accidents in his Swiss Cheese model, which is presented in Figure 1. The hazards appear from the right-hand side. Normally, their progress is stopped by successive layers of defences, barriers and lifeguards. If the process goes through all of these 'holes in the cheese slices', formally called the limited windows of accident opportunities, an accident will happen.

Kettunen et al. [START_REF] Kettunen | Safety management challenges and tensions in the European nuclear power industry[END_REF] regard redundancy as a method in improving safety by the duplication and overlap of critical factors like systems, functions and/or personnel. In general, redundancy can augment safety as such, but may also have counterproductive or unexpected effects, especially in case it is not managed properly. These unwanted effects can increase the complexity of the systems, which may hide individual failures and make them latent, so that they remain unnoticed and uncorrected and may even accumulate over time. Under these circumstances, a rather rare event might act as a trigger for an avalanche of unexpected events, which may be difficult to handle [START_REF] Kettunen | Safety management challenges and tensions in the European nuclear power industry[END_REF]. For situations of this kind, the Reason's Swiss Cheese model would work out excellently.

Data Mining in Flight safety

Several different methods are recognised as data mining methods and a mining system can use the combinations of several of these methods. Parsaye [START_REF] Parsaye | A Characterization of Data Mining Technologies and Processes[END_REF] describes data mining as searching in the data for the patterns of information to guide a decision support process. These, often called "the nuggets of knowledge", are hidden in vast amounts of data and are practically undiscoverable with conventional techniques [START_REF] Watson | Data Management: Databases and Organizations[END_REF].

Using mining software, knowledge of data is combined by an analyst with advanced machine learning technologies to discover the relationships. In the discovery process to find hidden patterns, there are neither hypotheses nor any other predetermined model of the characteristics of the patterns. Obviously large databases, like those of aviation incidents and other deviations, contain a large number of patterns, so that the user of the discovery system can practically never ask the right question. The mining process acts as a decision support system that will not give straight answers to the questions; that is why skilled analytical and technical specialists are still required to interpret the created output [START_REF] Kutais | Focus on the Internet[END_REF]. The process contains several steps or phases (cf.

Figure 2) that must be gone through to form knowledge from raw data. To be understandable the information must be presented with reports, graphs or in other suitable forms once found. With structured data, the explanation of a case usually tells the truth to a certain extent, but completed with narrative data it can be close to 100 %, at least theoretically.

Mining combined with other methods will give significant contributions to the decision processes. The idea to use text mining in the analysis of flight safety reports occurred along the need to analyse large amounts of narrative reports and when reports about successful text mining projects in the flight safety data analysis of English narratives were published [START_REF] Nazeri | Application of Aviation Safety Data Mining Workbench at American Airlines. Proof-of-Concept Demonstration of Data and Text Mining[END_REF][START_REF]Flight safety data analysis for Southwest Airlines[END_REF].

Testing Three Tools -Data Mining in Finnish

The basic idea of cluster analysis is that all the texts within each cluster have a high similarity in content [START_REF] Rosell | Text Clustering Exploration. Swedish Text Representation and Clustering Results Unraveled[END_REF]. This method was chosen for this study because it is an essential mining function in searching for similar documents, able to reveal a recurring hazard that might lead to an accident. It explores the data set and determines the structure of natural groupings without any preliminary assumptions. Another reason for its choice was the direct applicability to Reason's Swiss Cheese model presented in Figure 1. A third reason was that English literature gives several examples about using clustering in mining flight safety reports. These results have proved its better performance compared with more traditional statistical methods [START_REF] Saracoglu | A new approach on search for similar documents with multiple categories using fuzzy clustering[END_REF].

The beginning was finding text mining tools for processing Finnish. Three different systems seemed to be appropriate for benchmarking. The author was aware of one prototype (GILTA), one commercial product (TEMIS) with a Finnish module prototype, and one commercial system (PolyVista) with encouraging results mining Spanish, which seemed worth testing in Finnish. The Finnish Civil Aviation Authority granted the test data of 1240 cases (Target data on Figure 2), which created "a critical mass" for study.

The pre-processing produced filtered data containing 10572 word tokens, numbers and special characters, call signs, headings, the temperature, etc. The amount could be reduced to 8294 when parentheses and other similar characters without relevance were removed. The next procedure was preparing the lists of stop words (those to be ignored because of having no information) and synonyms. No transformation was needed because the data was extracted from one database.

The first round produced already promising results. Due to the Finnish module of TEMIS, no pre-processing was necessary. It created 26 clusters, their size varying between 108 and 21 reports. As the biggest cluster contained more than 100 clusters, the operator allowed the tool divide it into two sub-clusters with 58 and 50 documents. After the division, the biggest cluster included 78 reports. The similarity (range 5-1) of the five closest clusters varied from 3.41 to 2.07 %, which supports the assumption that the clusters are different from each other and thus this method in this data selection is reliable. Because the maximum degrees of explanation of the clusters, about 18 %, are relatively high, they prove that the clusters are composed of relevant reports and the most explaining reports alone might well reveal a trend that should be examined more thoroughly.

As Kloptchenko [START_REF] Kloptchenko | Text Mining Based on the Prototype Matching Method[END_REF] says, interpreting the mining results is more art and common sense than science. The one single mining round of TEMIS made the direct comparison of the results challenging. Despite it, due to the high efficiency of the system with its in-built module for Finnish and because the mining results did not seem to require major changes, missing the second mining round was not considered a cause for losing significant information.

The smallest clusters began to produce some directly applicable information indicating that the sizes of the clusters play a significant role in the applicability of the results. This must, however, be scaled with the amount of production data. Additionally, a couple of similar cases found do not automatically create a dangerous trend; the way they occur and the reasons causing them can only be estimated by a thorough examination and investigation by human analysts. The results of TEMIS ought to be examined differently from the two other systems due to its interface and way of producing results which differ remarkably from the others. This, however, does not mean that these mining results would not be coherent with those of the other ones.

GILTA (manaGIng Large Text mAsses) divided the data on both rounds into 100 clusters (named classes) on the basis of the nine most significant words. Hence, on the first round 63 clusters contained less than 10 reports. These were easily analysable by a human analyst and could already be considered good mining results, proving clustering to be a useful method for this type of data. Some of the bigger classes could be interpreted as being real clusters, but according to experience the sizes should be reduced to less than 20. The results that were produced in Excel-form made it possible to carry out a comprehensible analysis and comparison of them with the results found with other tools. The system left out four reports beyond defined clusters.

PolyVista was originally built for using in English, but due to encouraging results with Spanish, its applicability for Finnish was tested, too. The system set score 100 for the most content describing word of the cluster and correspondent values to the others. The scores of the ten most important words of each cluster were only available, not the reports. The reports of the clusters could be 'guessed' by comparing the scores with the most important words in GILTA changing their relative weights for comparison. The data was processed determining the number of clusters first to be 6 and then raising it up to 20 in a second step. When there were 20 clusters, the smallest of them contained 10 reports and the biggest 232. In the case of 20 clusters, in eleven of them the scores of the three most important words were more than 50. In the last cluster containing 10 reports, the scores of the 10 most important words were 50 or more, which can be considered a good mining result.

As one result of the first mining round, the need for tuning, especially the definition of stop words and synonyms was discovered. Some pure mistakes, like some common stop words and synonyms forgotten from the list, were noticed. A more significant problem was the appearance of some frequently used "common" words (like 'plane' with its synonyms 'airplane' and 'aircraft') skewing the results. Their role in the data was carefully analysed [START_REF] Lindén | Word Sense Discovery and Disambiguation[END_REF], using an application called NVivo to get a deeper analysis. NVivo itself has no mining characteristics, but is used in analysing qualitative information, especially meeting the requirements of deep levels of analyses on different quantities of data, varying between a couple of sentences and thousands of text rows. In this context, the most important feature was cross-examining the mining results applying its search engine and query functions. Almost one hundred checking procedures were made with synonyms and stop words to prepare the data for the second round. After the careful estimation of the impact of possible changes, no major ones were made to keep the process unchanged but making the results more accurate.

After the second mining round with GILTA and PolyVista was performed, the results were studied carefully using the professional skills of a flight safety inspector. The coherent clusters were taken into more detailed inspection. The progress as the change of distribution can be recognised through the increased percentage of 'sense making' 1 clusters, as for GILTA, illustrated in Table 1 displaying the minor, but perceptible change. First, the number of the relevant clusters increased from 9 to 11, and their average size diminished from 11.9 to 10.5 reports per cluster, shown in columns two and three. Further, the average weight of the nine most important words increased from 5.88 to 6.44 and the correspondent standard deviation diminished from 5.588 to 5.065, as shown in the two next columns. All these changes indicate the movement towards the aimed more homogenous clusters. As already mentioned, the mining results of PolyVista must be analysed differently. Although comparing the weights of the most significant words is a cursory method, it was noticed to be relevant in this context. The results are illustrated in Table 2 showing an obvious progress between the two rounds. On the first round, 40.0 % of the clusters seemed to belong to the 'sense making' clusters, on the second 52.3 %. The size of the clusters did not seem to have any linear impact, but on both rounds those were found among the smallest ones. The average sizes changed from the first round being 37.9 compared with 62.5 of all clusters to the second, being then 20.6 compared with 28.2. These numbers illustrate that more information is achieved from the results of round II. Proceeding with the same test and putting the results in a graphic presentation in Excel, the increased homogeneity was seen also from the 'centre of gravity' moving from the beginning of the rows rightwards as well as from the top downwards, when the clusters were sorted by the weight of the most significant words. It means that the number of clusters having more significant words increased. This occurred with both systems, indicating a slight improvement using this method, too.

Based on the professional skills and experience of the author, in case the safety personnel know what they are looking for, business intelligence (BI) methods could 1 Clusters, from which information can be seen clearly as such be applicable, allowing database queries using numerous keywords to search for known cases of a certain type or their combinations. BI could also be applied as a complementary method when mining is used to find something worth examining.

7

Results and Discussion

As already expressed before, the mining process does not give straight answers to the questions, but it acts as a support system for producing information for decision making. That is why experienced analytical and technical specialists are needed to interpret the created output. The testing process proved that data mining is neither an easy nor a fast method, but might be the only one for uncovering hidden information. All the results support the premise that it could reveal important safety information from fast accumulating, vast amounts of data, not accessible with other methods, to be used as an essential factor for strategic safety management. It is worth noticing that the test data was that contained no lethal trends, but in other case they could have been discovered and revealed using the method and tools as done in this study. An additional detail is worth noting -all the used tools left out almost the same reports as outliers.

The research process confirmed that text mining is a challenging task, especially in small language groups, where tools for text mining are scarcer than for big languages such as English which is an "easy" language for search technologies. Narrative text mining is generally demanding due to the multiplicity of languages spoken in the world. Especially languages with small user groups, such as Finnish, have to wait for efficient tools being developed much longer than the major languages. The search technologies are challenged by inflected forms and compounds. In Finnish, for example, the words may have thousands of inflected forms and in addition to that, they can be parts of compounds in almost countless combinations [START_REF] Karlsson | Yleinen kielitiede[END_REF]. On average, every seventh word can be found in its basic form in fluent Finnish texts [START_REF] Karlsson | Finnish grammar[END_REF]. From the point of view of language processing, two significant results were achieved: first, Finnish texts were successfully mined with a tool originally to be used in an English environment. Secondly, the Finnish module for TEMIS was successfully production tested with real Finnish production data.

The number of clusters proved to be significant in the process: the more clusters, the better results. Mining is an iterative process although it makes no sense to increase the amount of rounds too much. Although this study has offered data mining as one solution to growing challenges, it is to be noticed that it is only one among several methods. Its special characteristic simply expressed is the ability to find something that is not known but expected to exist. Data mining has been used successfully for several years by a couple of airlines and other actors in the aviation industry. The process chain, beginning from the collection of safety data and ending in revised regulations for improving flight safety, going through several mining rounds and analyses to produce issued aviation rules and instructions, is rather long and demanding. Despite its complexity, it is worth going through, even for avoiding one single accident.

Figure. 1 .

 1 Figure. 1. The Swiss Cheese model (adapted from[START_REF] Reason | Managing the Risks of Organizational Accidents[END_REF]Reason , 2000 [25, 26] [25, 26])

Figure. 2 .

 2 Figure. 2. The Knowledge Discovery in a Database Process (adapted from Fayyad et al. 1996 [29])

Table 1 .

 1 Results illustration in GILTA rounds I and II

	Round	Clusters	Average size	Average weight	Correspondent
					Standard Deviation
	I	9	11.9	5.88	5.588
	II	11	10.5	6.44	5.065

Table 2 .

 2 Cluster distribution change between rounds 1 and 2 in PolyVista

	Criteria / Round #	1	2
	'Sense making' clusters of all content	40.0 %	52.3 %
	Average size of all clusters (reports)	62.5	28.2
	Average size of 'sense making' clusters	37.2	20.6


Jian Dong

Hongxiu Li

Xianfeng Zhang

Classification of customer satisfaction attributes: An application of online hotel review analysis

Keywords: e-Service, e-Commerce, eWOM, Online reviews

With the wide penetration of Internet, online hotel reviews have become popular among travellers. Online hotel reviews also reflect customer satisfaction with hotel services. In this study we use online hotel reviews to classify the attributes of customer satisfaction with hotel services. The empirical data was collected via Daodao.com, the Chinese affiliated brand of online travel opinion website tripadvisor.com. Based on text mining and content analysis, we found that the following seven dimensions are important attributes generating customer satisfaction with hotels: hotel, location, service, room, value, food and dinging, and facility availabilities. Finally we concluded on the research findings and also highlight the research limitations and future research directions.

Introduction

The wide penetration of Internet applications in the hospitality and tourism field has greatly changed the way travelers retrieving tourism information, managing their trips, and booking flights or hotels. As [START_REF] Li | Understanding the Post-Adoption Behaviors of E-Service Users in the Context of Online Travel Services[END_REF] indicated that individuals yield large amount of user generated contents (UGC) via Internet, and the UGCs spread to others via various online media, such as email, chat rooms, personal Web pages, bulletin boards, newsgroups, discussion forums, blogs, social networks, and virtual communities [START_REF] Li | Understanding the Post-Adoption Behaviors of E-Service Users in the Context of Online Travel Services[END_REF][START_REF] Litvin | Electronic word-of-mouth in the Hospitality and Tourism Management[END_REF][START_REF] Reichheld | E-customer Loyalty-Applying the Traditional Rules of Business for Online Success[END_REF]. Consumers would like to rely on UGC to support their consuming decisions [START_REF] Li | Understanding the Post-Adoption Behaviors of E-Service Users in the Context of Online Travel Services[END_REF]. Since travelers can easily get access to the Internet, where they may freely express their subjective assessments, sentimental thoughts or even the emotional feelings towards the hotels, destinations, or the trip process, and share their travel experience with others, and the most important, individuals are also trying to use these travel-related UGC to support their travel decisions, such as hotels or destinations. According to [START_REF] Gretzel | Use and impact of online travel reviews[END_REF], three-quarters of travelers take online consumer reviews as the main information source when planning their trips [START_REF] Gretzel | Use and impact of online travel reviews[END_REF].

The study by [START_REF] Gretzel | Online Travel Review Study: Role & Impact of Online Travel Reviews[END_REF] confirms the vital role (77.9%) of online reviews in making decision "where to stay" [START_REF] Gretzel | Online Travel Review Study: Role & Impact of Online Travel Reviews[END_REF]. The similar trends also show in China. According to the recent report released by China Internet Network Research Center in 2013, 69.5% of the travelers in China considered online travel-related reviews as the essential factor supporting their hotel booking decision [6]. Information asymmetry has been dramatically eliminated [START_REF] Akerlof | The Market for Lemons: Quality under Uncertainty and the Market Mechanism[END_REF] by referring to the UGC, such as online reviews (also named as eWOM), based on travelers' previous experience.

This growing reliance on the Internet as the information source has inversely led to the prosperous development of different online opinion facilitated websites, and inspired travelers' enthusiasm in sharing their experience. In the hospitality and tourism industry, the professional social network websites normally employ numerical rating (overall rating or rating components) and text comments with or without numerical ratings [START_REF] Bronner | Vacationers and eWOM: Who Posts, and Why, Where, and What?[END_REF], such as tripadvisor.com, booking.com. The highlighted summary of the travel-related services performs like a powerful illustration of an Internet-mediated abstract system [START_REF] Giddens | Modernity and self-identity: Self and society in the late modern age[END_REF], or the reputation feedback system [START_REF] Resnick | Reputation systems: Facilitating Trust in the Internet Interactions[END_REF]. The popularity of online review makes the related websites gradually develop to be a popular intermediary in travel industry, or even a more trustful third party for individuals, when comparing to the traditional travel agents [START_REF] Jeacle | In TripAdvisor we trust: Rankings, calculative regimes and abstract systems[END_REF].

The rating system in hospitality and tourism industry, composed of rich numerical ratings and text contents from experienced travelers, can not only offers other individuals reliable information to support their travel decision, but also delivers to travel service providers, i.e. hotels, valuable feedbacks about their service quality, and even as a good marketing channel [START_REF] Resnick | Reputation systems: Facilitating Trust in the Internet Interactions[END_REF]. [START_REF] Ye | The impact of online user reviews on hotel room sales[END_REF][START_REF] Ye | The influence of user-generated content on traveler behavior: An empirical investigation on the effects of e-word-of-mouth to hotel online bookings[END_REF] found that the relationship between travelers' hotel rating behavior and the room reservation performance is significant [START_REF] Ye | The impact of online user reviews on hotel room sales[END_REF][START_REF] Ye | The influence of user-generated content on traveler behavior: An empirical investigation on the effects of e-word-of-mouth to hotel online bookings[END_REF]. A 10 percent increase in the travelers' ratings, will boost online bookings by more than five percent. Some researchers worked on the components of user satisfaction in order to better understand the factors determining hotels' service quality and user satisfaction. In practice, different online rating systems are also adopted to measure hotel's service quality, such as Tripadvisor.com, Booking.com.

Though online reviews have been argued to be important information source for both individuals and hotels, research on hotel customer satisfaction mainly focus on the attributes of service quality based on the perceptions from hotel customers, and little research has attempted to examine the attributes of hotel customer satisfaction from the perspective of online hotel review --the real feedback of hotel customers. In addition, few studies have explored to explain the importance level of various attributes generating customer satisfaction based on online hotel reviews, which might shed light on how hotel can satisfy their customers and retain customers, as well as how to recruit customers as marketing channel for their products or services via the WOM simultaneously. Thus, it is meaningful to investigate the attributes of hotel customer satisfaction based on the online reviews from real hotel customers.

The rest of this paper is organized as follows. A literature review on hotel customer satisfaction research is presented in the next section. Section three describes the research instrument development and the collection of the data. The results are presented in section four with a discussion on the findings as well. Section five presents the conclusions in this research and followed by the discussion on research limitations and future research directions.

Research background

Hotel customer satisfaction

Customer satisfaction has been an important research topic in the marketing field, such as to explore customer loyalty, and purchasing intention. According to [START_REF] Oliver | A Cognitive Model for the Antecedents and Consequences of Satisfaction[END_REF], customer satisfaction refers to an attitude [START_REF] Oliver | A Cognitive Model for the Antecedents and Consequences of Satisfaction[END_REF]. It is an evaluation formed by customers based on the expectations of what customers would receive from a product or service and on their perceptions on the performance of a product or service they actually received. Prior literature has attempted to identify the attributes which generate customer satisfaction as well as to identify the importance levels of different attributes in enabling user satisfaction [START_REF] Shanka | An Investigation into the Perceived Importance of Service and Facility Atributes to Hotel Satisfaction[END_REF]. Much of the literature researches on customer satisfaction from the lens of service quality [START_REF] Kandampully | Service Management: The New Paradigm in Hospitality[END_REF]. The research on user satisfaction of hotels also follows the research tradition of customer satisfaction and investigates customer satisfaction based on service quality of hotels, mainly employing survey, interview and case study research methods [START_REF] Deng | Fuzzy Importance-Performance Analysis for Eetermining Critical Service Attributes[END_REF][START_REF] Choi | Determinants of Hotel Guests' Satisfaction and Repeat Patronage in the Hong Kong Hotel Industry[END_REF]. The research stream mainly identifies the attributes of service quality. More details are presented in Table 1. [START_REF] Deng | Fuzzy Importance-Performance Analysis for Eetermining Critical Service Attributes[END_REF] identified the importance level of different indicators in generating customer satisfaction based on the SERVQUAL scale [START_REF] Deng | Fuzzy Importance-Performance Analysis for Eetermining Critical Service Attributes[END_REF], proposed by [START_REF] Parasuraman | A conceptual model of service quality and its implications for future research[END_REF][START_REF] Parasuraman | SERVQUAL: A multiple-item scale for measuring consumer perceptions of service quality[END_REF] [START_REF] Parasuraman | A conceptual model of service quality and its implications for future research[END_REF][START_REF] Parasuraman | SERVQUAL: A multiple-item scale for measuring consumer perceptions of service quality[END_REF]. [START_REF] Choi | Determinants of Hotel Guests' Satisfaction and Repeat Patronage in the Hong Kong Hotel Industry[END_REF] conducted empirical study in the context of hotels in Hongkong and found that staff service quality, room quality, value, general amenities, business service, IDD and security are important attributes in generating user satisfaction with hotels [START_REF] Choi | Determinants of Hotel Guests' Satisfaction and Repeat Patronage in the Hong Kong Hotel Industry[END_REF].

Survey

Hotels in Hongkong

Staff service quality (efficiency in check-in/out, helpfulness of staff, politeness/friendliness of staff, neat appearance of staff, efficiency of staff), Room quality (cleanliness, comfort of bed/mattress/pillow, in-room temperature control and quietness of room) Value (room value for money, hotel food & beverage value for money, comfortable ambiance of the hotel and hotel being part of reputable chain). General amenities (availability of mini bar, variety of food and beverage facilities, quality of food and beverage facilities, reliability of wake-up call, efficiency of valet/laundry service, efficiency of room service and availability of information desk) Business services (availability of secretarial service, availability of business-related meeting rooms, availability of business-related facilities). IDD (International direct dial) facilities Security (responsibility of security personnel, reliability of loud fire alarms and availability of safe box)

Research on online hotel reviews

Online travel reviews have become popular among travelers. Traveler would like to make comments on the travel services they have experienced and share travel experience with others. The popularity of online hotel reviews offers researchers the possibility to get access to online hotel reviews generated by hotel customers, and to get the real data reflecting travelers' satisfaction, but not based on their perceptions about travel services as in the traditional research on user satisfaction.

Recently, quite much research on hotel customer satisfaction has used online hotel reviews in their research to explore user satisfaction. Though these researches are also trying to identify the indicators of customer satisfaction, the same as the traditional research, its research context and research methods are different. Normally text mining and content analysis are employed in these researches. [START_REF] Chaves | Analysing Reviews in the Web 2.0: Small and Medium Hotels in Portugal[END_REF] conducted content analysis of online hotel reviews on the SME hotels, and found customer satisfaction with hotel services are mainly determined by the indicators related to room, staff, location and neighborhood of hotels [START_REF] Chaves | Analysing Reviews in the Web 2.0: Small and Medium Hotels in Portugal[END_REF]. [START_REF] Zhou | Refreshing Hotel Satisfaction Studies by Reconfiguring Customer Review Data[END_REF] made analysis of the online hotel reviews in a city in China and found that physical setting, (including room, hotel, and food), value, location and staff are the most important attributes generating hotel user satisfaction [START_REF] Zhou | Refreshing Hotel Satisfaction Studies by Reconfiguring Customer Review Data[END_REF]. More detailed research based on online hotel reviews is presented in Table 2.

Data collection

The source selection of hotel review websites is crucial to the research. The platform should be capable of assembling larger population and generating higher external validity. Based on the rule, daodao.com was finally opted for the online hotel review/eWOM data source. Daodao.com is fully affiliated to the world's largest travel site -Tripadvisor, which operates worldwide in 42 countries, and generates more than 150 million reviews and opinions covering over 4 million accommodations, restaurants and attractions. Since launched in 2009, Daodao.com has been providing valuable insights to Chinese travelers in trip planning, for example, over 3 million reviews in Chinese has been accumulated at the website of Daodao.com by February 2014. Currently Daodao is ranked as the top one tourism-related UGC website among the Chinese community. According to the iResearch statistics, the monthly visits of Daodao.com have reached 7.62 million in August 2013.

Only 4 and 5 star hotels are considered in this research.Sanya, a coastal city deemed as the oriental Hawaii in the far south part of China is selected. Sanya is the second largest city of Hainan which is an isolated island in the south sea, and is also the designated international tourism island by Chinese government in December 2009. Sanya has been a popular leisure travele destination for its tropical attractions and the yearly wide low PM2.5, when comparing with other bigger tourism cities like Beijing or Xi'an. A number of 100 top star hotels located in Sanya are registered in daodao.com, consisting 49 five star hotels and 51 four star hotels. The 100 hotels generated a total volume of 24051 reviews, with online reviews on individual hotel ranging from 2 to 1744, and averaging in 240.

All reviews are crawled from the website by using a spider program. The two-week data crawling process started from March 23, 2014, and ended in April 5, 2014. Numbers are also revised and re-crawled when there are new reviews during the two weeks.

Taking in sight that the reviewers of Tripadvisor are from 42 countries and can write reviews in 25 languages, Daodao.com merged international reviews in the general opinion pool for each hotel. Correspondingly, there are numbers of reviews written in other languages, such as English, Russian, Japanese, and so on. This portion of opinions is not considered in the research so as to neatly focus on the context of Chinese eWOM. Daodao.com also cooperates with similar review or booking brands, through borrowing travelers' opinions left in other branded websites like Expedia and Agoda. These segments are also deleted, since differed reviewing regulations in diversified platforms may deliver varied thinking. The online hotel reviews are finally purified to 19,659 items, with individual hotel reviews ranging from 1 to 1632.

Data content mining procedure

Due to the unique feature of Chinese language, one native Chinese software called ROST CM6.0 is chosen to conduct the research. ROST content miner is designed by a research group from Wuhan University in China, for the purpose of solving the problems that other non-Chinese originated content mining software met in parsing and merging Chinese words. ROST CM6.0 is capable of splitting, filtering, merging Chinese words, and researchers can also automatically count frequencies, cluster and classify the words, construct the sentiment networks or social networks, and display the co-occurrence matrix. It has been downloaded by researchers worldwide from more than 100 universities to deal with Chinese qualitative data in social sciences.

The word parsing and initial word frequency counting is operated first, followed by the filtering stage. Though ROST CM6.0 has its own filtering dataset, the manually selected filtering lists are still needed for each individual research under its unique context. The full list of the parsed words is therefore carefully reviewed, while those words that either do not conforms to the common Chinese usage or contains no meanings under this research context are selected and added in the filtering database. When the filtering word list is done, the parsed word dataset is then re-input in the software to generate the new word frequency counts.

Data Coding

The filtered output displays a number of 1899 items of words with the frequency of 1 or above. The highest frequency climbs up to 35089, whereas a list of 812 words counts less than 10. The number of words with frequencies up from 57 takes the top 499 lists, and those ranging from 11 to 49 surmounts 588. Among the 1899 word lists, the word hotel ranks the highest, being mentioned by 35089 times. Room and service follow with the frequency of 18482 and 15111. Surroundings, amenities, convenience, breakfast, seashore, sandy beach and sea view are also the frequently used words in the top 10 lists.

Though the review portraits are sketched out by referring to the 1899 word lists, it is still far from reaching the fundamental essence. The coding process is therefore continued so as to stress out the important word groups and accordingly pinpoint the key dimensions that travelers care. The top 500 words are picked out and reviewed carefully. Through aggregating the synonyms or similar words, the 500 vocabulary is then reduced to 100 groups. The frequency of the word groups range from 56 to 37342, and average in 3300. The denomination related with hotel still ranks the first, including hotel, resort, villa and etc. Room, beach, service, location, facilities, environment, cleanness, swimming pool and price also enlist in top 10 lists. Generally speaking, the groups of words outlining the varied facets of each dimension still take the majority. Take service for instance, vocabulary pools specifically describing empathy, politeness, professionalism each take the frequency of 7670, 3735 and 2590.

In order to reveal the diversified dimensions and explain their respective significance, attribute coding is conducted according to the scales proposed by prior literature. A small number of word lists are deleted, for either they are the general denomination, such as hotel name related lists (hotel, resort, villa and etc.), or the ambiguous words that cannot unveil the real context, like lovely, delicious, tasty.

Based on the literature review and careful coding, the 100 word groups are categorized into seven attributes, each containing detailed indexes, as shown in Table 3. Among the seven attributes, hotel, location and room attracts the majority of the stress, respectively taking the percentage of 25.9%, 21.7% and 21.4%, which clearly reflect the travelers' willingness to stay in a conveniently located and well equipped hotel, and to enjoy the comfort of the room fully supported by the well furnished amenities. Service and food are also frequently mentioned, sharing another proportion of 22.4% in altogether. This finding also conforms to the prior research finding of [START_REF] Li | Determinants of Customer Satisfaction in the Hotel Industry: An Application of Online Review Analysis[END_REF] that service and food are important attributes generating customer satisfaction with hotel [START_REF] Li | Understanding the Post-Adoption Behaviors of E-Service Users in the Context of Online Travel Services[END_REF]. Surprisingly, only no more than 5% of the review words have connections with the elements of hotel value. The finding reflects the true thoughts of travelers. Travellers consider more about quality of travel service, and less on the hotel value considering the popularity of Sanya as a leisure travel tourism destination and aiming for relaxation when traveling to Sanya. The denomination regarding the general facility availabilities, ambiguous in the underneath context of either hotel or in-rooms, for instance, facilities, equipments, deployments, hardware, equipped, and etc., also counts for 3.8%, though it cannot unveil much significant findings.

In the attributes related to hotels, the index of beach and sea view far surmount the other indexes, standing over one third of review frequency in its category. This is crucial to hotels in the tropical cities like Sanya, which is also why most top star hotels locate nearby the sea to avail beautiful sea view in-rooms possible, and to run their own beach with seashore supports for enjoyment. Room rates of those hotels can even triple the price of the similar hotels which are not near the sea, since they follow the fashion and pinpoint the unique feature. The element of decoration turns to be the second important attribute related to hotels, sharing a percentage of 19.0%. This finding reveals that customers care very much about the hotel decoration. The decoration, furnishing, ornamentation of hotels can help customers to get the feeling of luxury, modern, fashionable, dated and etc. The public facilities and fitness and entertainment facilities are the two commonly mentioned indexes, individually standing for 12.5% and 15.5%. Lobbies, elevators, corridors, and facilities for children and elder people sketch out the public facilities travelers concern, whereas fitness and entertainment facilities mainly refer to fitness centers, sonar and message, bars and clubs, and swimming pools. In addition, reviewers also care about the chains or star ratings of the hotel (7.9%), revealing that endorsement based reputation can truly make some influence towards the travelers. Some reviewers also mentioned about the beautiful surroundings and ambience (7.5%) inside the hotel, such as gardens, fresh air, quietness and etc. The two non-significant yet indispensible elements, parking and in-hotel commuters and Internet facilities are also highlighted, though respectively with only 2%.

The general denomination of room has been intensely remarked in the room attribute, constituting over one third of the proportion. Nonetheless, the detailed hints regarding room facilities still draw a panoramic view. Cleanness (24.5%) and comfort of the room (22.5%) are the two vital variables to measure the perceptions customers hold towards the room, standing more than half of the detailed descriptions. To well explain the comfort of the room, noise & quietness (16.4%) and sleep quality (9.5%) are proposed multiple times to reflect the two influencing facets. Toilet & bathroom (13.9%), furniture & electronics (12.5%) sharing the portions of 26.4% altogether, primarily emphasize the internal facilities either in rooms or in the bathroom, which can provide the solid supports to customers. Interestingly, a great number of reviewers stress out the room size and layout (23.1%), particularly referring to size, stories, balcony, casement and floor windows, space, scenery, airiness, etc. A small number of reviews comment on beddings (3.5%), including pillows, beds, sheets, and mattress. Of course, well beddings can normally bring comfortable and tight sleep.

Same as the prior literature, travelers discuss the hotel location in regard to its proximity to public transport, attractions and city centers, and its general environment. Surprisingly, travelers intently headline the surrounding environment of the hotel (51.2%), through adopting words like landscape, scenery, beautiful, tropical, greens, nature, and etc. Expectancy and conformity theory might help explain this finding. Travelers who choose the most famous tropical city of China mainly expect to experience the exotic views. Accessibility of the public transportation (22.3%) draw some heeds, while vicinity to the attractions (15.9%) follows. The proximity to city center (10.6%) is comparatively the least highlighted. This fits in the research context, since Sanya is more a tourism spot than a gigantic city with prosperous shopping malls.

The word service in single has been mentioned for 15111 times, standing nearly 38% of the service attribute, though there are many facets of service that have been highlighted. Friendliness and helpfulness (44%), and staff and professionalism (41%) are the two equally important index, stating either the consideration of the service people, i.e. warm, polite, greeting, kind, patient, attentive, smile, help and etc., or the professionalism that displays through efficient, speedy and timely service, and their neat appearance and nice manage. Front desk service and reception (11%) can also deeply impress the customers, which implies in the process of check-in/out, inquiry, complaint, room change, welcome etiquette, and etc. Pick-up service (4%) attracts the least concern, yet it is still vital for hotel.

Dining and food is also frequently mentioned. The general description regarding food, foodstuff, eating, dining, feast etc. takes some proportion (18%), and portrait the overall profile. The two elements depicting dining and food are the dining place and the contents. Food and beverage takes the transcending advantage with the percentage of 87.4%, including the variety of food (western/oriental food, buffet, breakfast/lunch/supper, seafood, cakes/fruits/ barbecue etc.), beverage (drinks, liquors, juice, coffee, etc.), and the quality of food (delicious, flavor, etc.). Breakfast attracts the highest remarks (36% out of the category), since most hotels put breakfast in the package bundle. The dining place (12.6%), namely Chinese/western restaurant and room service, also counts. Value is mainly reflected by means of perceived value (23.1%) and price (76.9%), with the former revealing the customers' perception towards value (value for money, economic, cheap, worthy, etc.), and the latter being price of room, food, service, or the discounts and freebies. This research attempts to identify the attributes generating customer satisfaction with hotels based on the online hotel reviews from hotel customers. Based on text mining and content analysis, we found that the following seven dimensions are important attributes generating customer satisfaction with hotels: hotel, location, room, service, food and dinging, value, and facilities. Hotel related attributes is the most important factors travelers care about and influence customer satisfaction strongly, followed by location, room, service, food and dining, value and facility availabilities. The research finding implies that physical settings of hotel (such as hotel, room), services and location play more important role in generating customer satisfaction, whereas dining and food, value and facility availabilities are not as so important as the role of them.

The research findings also offer some practical guidelines to hotels on how to improve customer satisfaction. Providing good service and satisfying customers are always important for hotel.

Limitations and future research

The same as other research, this study involves some limitations that need to be acknowledged. First, this research was conducted in context of hotels in Sanya in China. This gives a possible avenue for future studies to research on hotels in different cities or different countries to see whether there is difference among varied cultural background of hotels. Second, to compare the findings of research on online hotel reviews and on traditional customer perceptions, such as survey, might also be interesting in this field.

Table 1

 1 Research on hotel customer satisfaction from the lens of service quality

	Literature	Scales
	Deng 2008 [17]	Responsibility and empathy: Personal warm care given by staff, Have
		customers' best interest at heart, Easy to get staff's attention & help.
	Case study, and	Readiness to respond to customer's requests, Knowledgeable to answer
	survey	customers' request, Courtesy and friendliness of staff, Individual attention
		for customer, Willingness to help customers, Understand the specific needs
	Hotels in	of customers, Provision of safe environment and equipment.
	Taiwan	Reliability and assurance: Provision of services as promised, Dependability
		in handling customers' service problem, Reasonable price, Prompt reply to
		customers, Perform service right at the first time.
		Tangibility: The physical facilities are visually appealing, Multiple hot
		spring facilities, Availability of adequate fire & first aids facilities and
		instructions, Cleanness of hot spring facilities, Convenient hotel location.
	Choi & Chu
	2001 [18]

Table 2

 2 Research on online hotel reviews , breakfast, bed, price, restaurant, pool, bathroom, airport, downtown, view, shopping, shower, dirt, coffee, towel, noise, smell, courteous, pillow, buffet, noisy, attractions, smoking, accommodating, pay, expensive, mall, cheap, employee, eat, rate, decor, dine, sheet, valet, Disney, toilet, clerk, refrigerator, stain, broken, bath, bus, affordable, store, cost, shops, sink dinner

	Literature	Scales
	Chaves et al. Room: cleanliness, size, silence and bed. Cleanliness, confort, scenery and

Table 3

 3 High Frequency Review Words Coding Profile

	Index		Ratio	Notes and Examples
	Hotel (25.9%)
	-beach & sea view		33.5	beach, seashore, sea view, sand, sea, etc.
					renovation, furnishing, ornamentation, luxury, modern,
	-decoration		19.0	etc.
					fitness, sonar & message, bars & clubs, swimming
	-entertainment facilities 15.5	pools, etc.
	-public facilities -star ratings		12.5 7.9	lobbies, elevators, corridors, fountains, slides, toys, etc. star ratings, reputation, chain, brand, 1 st class, etc.
	-ambience		7.5	natural ambience like gardens, fresh air, quietness, etc.
	-Internet facilities		2.1	computers, Internet, cable, Wi-Fi, etc.
	-parking & commuters	2.0	parking lot, in-hotel storage battery car, etc.
	Location (21.7%)		36.6/-	general description, e.g. location, district, distance, etc.
					landscape, scenery, beautiful, tropical, greens, nature,
	-environment		32.4/51.2	etc.
	-close to transportation	14.2/22.3 bus, airport, railway station, walking, taxi, etc.
					famous scenery spots and attractions, and place for
	-close to attractions		10.1/15.9	diving, etc
	-close to city center		6.7/10.6	city center, shopping, supermarket, downtown, etc.
	Room (21.4%)		34.5/-	general descriptions, e.g. room, guestroom, indoors,
					etc.
	-cleanness		16.0/24.5 cleanness, cleaning, disinfection, dust,rubbish, etc.
	-room size and layout		15.2/23.1 size, stories, balcony, windows, space, scenery,
					airiness, etc.
	-comfort		14.7/22.5 quietness, sound proofing, noise, comfort
	-toilet & bathroom		9.1/13.9	bathroom facilities, e.g. shower, bathtub, towel,
					slippers etc
	-furniture & electronics 8.2/12.5	curtain, carpet, sofa & chairs, telephone, TV, cooler,
					etc.
	-bedding		2.3/3.5	bed, mattress, pillow etc
	Service (14.3%)		38/-	the single word of service for general description
	-	friendliness	&	28/44	warm, polite, greeting, kind, patient, attentive, smile,
	helpfulness			and etc.
	-	staff	&	26/41	efficient, speed, timely, manage, neat appearance, and
	professionalism			etc
	-front service &	7/11	check-in/out, inquiry, complaint, welcome etiquette,
	reception			and etc.
	-pick-up service		2/4	pick-up service including shuttles, drivers, pick-up, and
					see-off
	Dining & Food (8.1%)	18.1/-	general description, e.g. food, foodstuff, eating, etc.
					variety, quality, and taste of food, drinks and liquors,
	-foods & beverages		71.5/87.4	etc.
	-restaurants		10.4/12.6 Chinese/western restaurant and room service
	Value (4.8%)
	-price		76.9	room/food charges, service fee, discounts, freebies, etc.
	-perceived value		23.1	value for money, economic, cheap, worthy, etc.
	Facility availabilities		facilities denomination ambiguous in the underneath
	(3.8%)			context, such as facilities, equipments, deployments,
					hardware, equipped, and etc.

Acknowledgement

This research was supported by the National Natural Science Foundation of China (Grant No.71362027), and MOE Humanities and Social Sciences Project of China (No.13YJC630228).