Alban Gabillon
email: alban.gabillon@upf.pf

Jean-Pierre Barriot
email: jean-pierre.barriot@upf.pf

Youri Verschelle
email: youri.verschelle@upf.pf

Bernard Ducarme
email: bf.ducarme@gmail.com

TOWARD A NORMALIZED XML SCHEMA FOR THE GGP DATA ARCHIVES

Keywords:

Since 1997, the Global Geodynamics Project (GGP) stations use a text-based data format. The main drawbacks of this type of data coding is the lack of data integrity during the data flow processing. As a result, metadata and even data must be checked by human operators. We propose in this paper a new format for representing the GGP data. This new format is based on the eXtensible Markup Language (XML).

INTRODUCTION

Since 1997, GGP stations use a text-based data format known as PRETERNA. The main drawbacks of this type of data coding is the lack of data integrity during the data flow processing. As a result, metadata and even data must be checked by human operators. We propose in this paper a new format for storing and disseminating the data coming from the worldwide GGP network of superconducting gravimeters, in order to streamline the data processing and to enable the scientific community to access these data and their ancillary metadata through distributed, integrated information technology systems and virtual observatories. This new format is based on the eXtensible Markup Language (XML, Bray et al., 2006) that ensures the consistency, reliability and integrity of the data over the Internet and between any data processing platforms. Section 2 of this paper reviews the GGP network of superconducting gravimeters, section 3 outlines the main drawbacks of the current text-based GGP data format. Section 4 presents our new data format based on an XML schema [START_REF] Thompson | XML Schema Part 1: Structures, Second Edition[END_REF]. Section 5 concludes this paper.

THE GGP NETWORK OF SUPERCONDUCTING GRAVIMETERS

The Global Geodynamics Project (GGP) is an international network of 25 superconducting gravimeters [START_REF] Crossley | Network of superconducting gravimeters benefits a number of disciplines[END_REF] in operation since July1997, under the umbrella of the International Association of Geodesy (IAG). The continuous monitoring of timevariable gravity from seconds to years is a tool to investigate many aspects of global Earth dynamics and to contribute to other sciences such as seismology, oceanography, earth rotation, hydrology, volcanology, and tectonics. Another promising application is the use of SG subnetworks in Europe and Asia to validate time-varying satellite gravity observations (GRACE, GOCE) due to continental hydrology and large-scale seismic deformation. GGP plays a small but important role in the Global Geodetic Observing System (GGOS), a primary program of the IAG to coordinate the recording and dissemination of all geodetic data for Earth monitoring, namely the recording of the gravity field and especially its time variations [START_REF] Crossley | The Contribution of GGP Superconducting Gravimeters to GGOS[END_REF]. GGP was incorporated into the IAG as Inter-Commission Project #3.1 in 2003; it is a joint project between Commission 3 (Earth Rotation and Geodynamics) and Commission 2 (The Gravity Field). It is expected to become a full Service of IAG in 2014.

THE CURRENT GGP DATA FORMAT

All GGP stations use the data format proposed by [START_REF] Wenzel | The nanogal software: Earth tide processing package[END_REF], known as PRETERNA, in which every value (predominantly gravity and pressure), are time tagged in the original units (volt).The only processing is a decimation filter from the original samples to 1-minute values, but no other corrections are done. The full signal is saved with a precision of 7.5+ digits, ensuring that the tides are adequately recorded as well as the smallest tidal waves. A full discussion of data treatment is given in [START_REF] Hinderer | Superconducting Gravimetry[END_REF]. Users should realize that gaps, spikes and offsets still have to be treated if a clean continuous time series is required, or otherwise avoided if the series is processed as non-contiguous blocks. These 1-minute raw data files are stored at GFZ Potsdam (http://isdc.gfz-potsdam.de/). The International Center for Earth Tides, a Service of IAG, provides corrected minute data (i.e. manually cleaned for gaps, spikes and offsets) on their website (http://www.bim-icet.org/), but this treatment is designed for tidal analysis and may not be suitable for all purposes, especially long period studies. A GGP 1-minute file is a column-driven file made up of 2 sections, each section being subdivided into 3 parts:

1. The header 1.1 -first ten required lines (ancillary information about the GGP station and instrument) Each data record consists of 3 fields. The first field records the date and time of the measure in the format specified by the W3C. The second field is the gravity measure. The last field is the pressure measure. Specified bounds (from 0 to 1000) correspond to physical limitations.

The header includes several data fields, filename, author, start_time and end_time. filename and author are self described. start_time correponds to the date and time of the first data record, end_time corresponds to the date and time of the last data record. Other fields (station, instrument and state) are complex elements containing nested subfields. instrument contains some data regarding the instrument that recorded the time series. station contains some data referring to the station which hosts the instrument. state contains some data which are specific to the version of the time series obtained after a given processing step. Indeed, a given time series can follow a processing chain and each step in the processing chain outputs a new state of the time series.

The station element contains 3 fields code, region and country identifying and locating the station.

The instrument element contains several fields and complex elements describing the instrument which produced the time series. serial_number, name, vectorial_type and brand are the simple data fields whereas latitude, longitude and altitude are the complex elements containing nested subfields. All these instrument parameters remain unchanged over the various versions (states) of a given time series. serial_number, name and brand are self described. vectorial_type indicates the levitating ball (1 for low, 2 for up). latitude, longitude and altitude contain some data about respectively the latitude, the longitude and the altitude of the instrument at the time it produced the time series. The latitude element (respectively the longitude element) contains some self described fields related to the latitude (respectively the longitude) of the instrument.

The latitude (respectively longitude) element contains some self described data fields related to the latitude (respectively longitude) of the instrument (see below)

The altitude element contains some self described fields related to the altitude of the instrument. Note that system is a complex element which either includes a geoid data field or an ellipsoid data field (see below).

The state element consists of one data field code and one complex element release. code identifies the chain processing step (see http://www.eas.slu.edu/GGP/ggphome.html).

Each state (i.e. version of the time series) can be subject to several releases (at least one). release records some data which are specific to each release.

The release element contains several fields and complex elements describing some parameters which are specific to a given release of a time series state. number, comments and status are self described.

Other fields (gravity, pressure and phase_lag) are complex elements containing nested subfields. They all contain some specific instrument parameters which were specifically set for the release.

The gravity (respectively pressure) element (see below) contains 2 data fields and 1 complex element. confidence_index is unused and offset (float from -10000 to 10000) indicates a general offset on gravity for the considered data. Note that, contrary to the previous format, there should be only one possible offset value for each time series. calibration is the complex element and contains nested subfields (see below).

The calibration element which is nested in both the gravity and the pressure element contains 3 data fields value, error and method. These fields are self described.

The phase_lag element contains 3 data fields value, error and method. These fields are self described.

CONCLUSION

We hope that the format we proposed in this paper will serve as a base for the future official GGP data format.

  (V) pressure(V) C*********************************************************Schema GGP.xsd Description Our schema divides GGP files into 2 blocks: The header which consists of a set of header fields and the data block which corresponds to the time series and which consists of an unbounded number of data records.

Table 1 .

 1 An example of data file is given in Table1, and the complete data format descriptor (last updated 10 December 2008) is available for download at http://www.eas.slu.edu/GGP/ggpnews19a.pdf. This format, in use since 1997, is based on Hollerith punched cards style formats, as FORTRAN character fields (A descriptor), integer fields (I descriptor) and float fields (F descriptor). The main drawbacks of this type of data coding is the lack of data integrity during the data flow processing as described at http://www.eas.slu.edu/GGP/ggpnews5.pdf, and the lack of a strict enforcement of data field lengths. As a result, metadata and even data must be checked by human operators. Moreover, this data format includes text-based tags like 77777777 or 99999999 without implicit semantics. Current GGP data format

	1.2 -optional text lines inserted by SG group (free comments)
	1.3 -two required text lines
	2. The data
	2.1 -one required introductory line
	2.2 -lines of timetagged gravity and pressure data
	2.3 -last required termination line
	Filename	: H2050300.GGP
	Station	: Bad Homburg, Germany
	Instrument	: GWR CD030_U
	Time Delay (sec)	: 45.0	2.0	estimated
	N Latitude (deg)	: 50.2285	0.0001 measured
	E Longitude (deg) : 8.6113	0.0001 measured
	Elevation MSL (m) : 190.0000	0.1000 measured
	Gravity Cal (uGal/V): -67.92	0.02 measured
	Pressure Cal (hPa/V): 1.0	0.001 nominal
	Author	: P. Wolf (peter.wolf@bkg.bund.de)
	yyyymmdd hhmmss gravity

We are currently developing a toolbox to allow easy back and forth conversion between the old and our new xml format. We are also writing several XSLT (Kay, 2007) style sheets for visualization of the XML GGP data.

THE NEW XML DATA FORMAT

Writing GGP files in XML has several advantages:

• XML is a markup language. Data fields are clearly separated by tags.

• Since tags are user-defined (XML is not restricted to a predefined limited set of tags like HTML), tags convey semantics specific to the application domain.

• XML files can be automatically analyzed for data treatment/presentation with an XML parser.

• An XML file can be checked against an XML schema. An XML schema is a special XML file that specifies a vocabulary identified by a namespace (Bray et al., 2006), and some grammatical rules. An XML file that respects the rules dictated by a particular XML schema is said to be valid. Checking the validity of an XML file is an automated process.

In this section, our objective is to propose an XML GGP schema. Our XML GGP schema defines the legal building blocks of the XML GGP files. Our XML GGP schema defines its own namespace identified by the GGP web page URL: http://www.eas.slu.edu/GGP/ggphome.html. The schema itself can be accessed at the following URL: http://pages.upf.pf/Alban.Gabillon/ggp/ggp.html.

Our schema is described in table 2. Regarding this description we can make the following comments:

• Our schema is a preliminary version of what should become a normalized XML GGP schema officially approved by the IAG. • Sample GGP files should can be validated online by using the W3C validation service: http://validator.w3.org/ • Our schema uses the standardized W3C built-in data types [START_REF] Biron | XML Schema Part 2: Datatypes Second Edition[END_REF].

• We are planning to improve our schema by referring to already official schemas and vocabularies defined by international organizations like the Open Geospatial Consortium (OGC) (http://www.opengeospatial.org). Such already existing vocabularies could be used to define some concepts like latitude, longitude etc. • We are also planning to refer to the Sensor Model Language (SensorML) that provides standard models and an XML encoding for describing the process of measurement by sensors and instructions for deriving higher-level information from observations [START_REF] Botts | OpenGIS Sensor Model Language (SensorML) Implementation Specification[END_REF]. • Checking the validity of a time series and its associated metadata can be done statically from the corresponding XML GGP file. It can also be done dynamically during the data flow processing.


Tegawendé F Bissyandé
email: tegawende.bissyande@uni.lu

Daouda Ahmat

Jonathan Ouoba
email: jonathan.ouoba@labri.fr

Gertjan Van Stam
email: gertjan.vanstam@machaworks.org

Jacques Klein
email: jacques.klein@uni.lu

Yves Le Traon
email: yves.letraon@uni.lu

Sustainable ICT4D in Africa: Where Do We Go From Here?

Keywords: ICT4D, Africa, development, research topics and priorities

In recent years many researchers in Africa and beyond have devoted considerable resources investigating ways to harness the potential of ICT for improving users' livelihood in developing areas. Topics and domains of interest appear to be broad with recurring themes and solutions. Unfortunately there are no clear research roadmaps on what is urgent and of the state of the art solutions. In this position paper for the AFRICOMM series of conference, we propose to investigate some priorities for ICT4D in Africa. We believe that our work could motivate researchers and create a synergy around a few important challenges of ICT4D in Africa.

Introduction

Information and Communication Technologies have shaped todays' world, and keep drawing the future by enforcing globalization and its associated challenges and opportunities for trade, cultural exchange, and innovation. In developing areas, the frontrunner initiatives to move millions of people out of poverty are recurrently said to be based on ICT. ICT for development (ICT4D) is thus the latest paradigm that occupies researchers, not only in computer sciences, but also in humanities. Unfortunately, except a few reports on experiments, there are very few studies that unequivocally show the success or ICT4D research to improve users livelihood in Africa. Furthermore, and what is more important, there are even fewer empirical studies that suggest critical fields where ICT4D would benefit the populations.

Conferences on ICT4D are now legion. At AFRICOMM, every year, researchers from Africa and beyond are proposing various techniques and approaches for ICT4D. However, as readers of papers from previous sessions of this conference, we always wonder to whom the authors make suggestions of such ideas. Indeed, often, the techniques appear to be unrealistic given the available resources and the cultural model in developing countries as well as their priorities. We thus believe that there is a need to advocate for a sustainable ICT4D research. We hope that after a solid discussion on our contributions at the conference, together with all participant researchers we will pave a new roadmap to serve African populations with ideas and solutions (1) that they care about, (2) that could really help them, and (3) that constitute a step towards overcoming the challenges of the digital divide. This position paper is also aimed at rallying young (and not so young) researchers across Africa who wish to partake in ICT4D research. Our contributions in this paper are:

1. we succinctly detail the motivation for this paper, establishing the need for questioning ICT4D research for Africa. 2. we discuss what we believe to be critical avenues of research for Africa, categorizing these topics into short, medium and long term impact-oriented research. 3. finally, we suggest research goals, by distinguishing between urban areas and rural areas in developing regions to show that unlike in developed countries, the ICT4D priorities in such areas are very much different in Africa.

The remainder of this paper is organized as follows. Section 2 provides an indepth discussion of our motivation. Section 3 details some research avenues with their degree of priority for Africa. Section 4 discusses research topics following the context in Africa. Section 5 provides an illustrated discussion on our work and presents a proposition to implement our recommendations. We conclude in Section 6.

Motivation

The intentional use of communication to foster development is not new. As Heeks has recently described, in the mid-1950s there was already initiative for broadcasting development communication, computing/data processing for back office applications in large organization both of government and private sector in developing countries [START_REF] Heeks | Ict4d 2.0: The next phase of applying ict for international development[END_REF]. Nowadays, mobile phone has shaped its way through to become the archetypal application for ICT4D because of its affordability and because it allows to focus on the poor as producers and innovators of ICT. With the proliferation of data and bandwidth, Hilbert has suggested to now turn our eyes towards Big Data as a new paradigm for ICT4D [START_REF] Hilbert | Big data for development: From information-to knowledge societies[END_REF].

There seems therefore to be a consensus on how ICT4D is evolving as a notion. However, in practice this evolution is not clearly witnessed in the improvement of poor people's lives. Furthermore, we note three important concerns with ICT4D research in and for Africa.

Absence of agenda. No agenda has been set on what should be done by the next decade or so to achieve any fixed goal. Even policy makers set vague objectives and then tag 'ICT' as a solution to their goals. In such a context, researchers cannot be expected to succeed in unclear endeavors. An agenda would also allow to regularly check the progress, continuously improve the means dedicated, and reassess one's ambitions. The UN ICT Task force attempts to implement such an agenda since 2005 [START_REF]Tools for development: Using information and communications technology to achieve the millennium development goals[END_REF]. However, it appears that they set various global and vague goals that mainly concern the government bodies and NGOs that are funded by the UN agency.

Little knowledge on needs and requirements. Second, we note that to the best of our knowledge, there are very few empirical studies that characterize the actual needs of developing countries. There are even fewer studies that discuss the requirements for ICT solutions to be proposed. Such studies however to be prerequisites in other no more important fields of research []. As we discussed in previous work, the particularities of the african context should drive the design of ICT4D solutions [START_REF] Ouoba | Leveraging the Cultural Model for Opportunistic Networking in sub-Saharan Africa[END_REF].

Few return on experiences. What have researchers achieved so far to improve poor people's livelihood? Where have we failed and why? These questions persist for African developing countries because of a serious lack of documentation on failed/successful experiences. Practitioners are often afraid to report on their failures so as to maintain funding, while researchers are not keen to thoroughly validate the real adoption of their solutions, preferring to require that poor people adapt to them, rather than refining their techniques to adapt to the context [].

Critical research avenues

In this section we discuss research avenues that we see as critical today. We have categorized them so as to ensure that we effectively tackle the issues that we have raised in our detailed motivation (cf. Section 2). First we advocate for empirical studies to shake down all beliefs about the needs of poor people and all wrong hypotheses on the context that could derail the applicability of ICT4D research.

Empirical studies

Is broadband connectivity necessary everywhere in developing areas? Is e-Learning even an interesting topic for illiterate people in Africa? Such questions require answers for which we unfortunately do not have definite answers []. ICT4D has this particularity that it employs sophisticated technologies to help people out of poverty. However, there are already a number of researchers, specially in sociology and anthropology, who conduct research on the specificities of developing areas and their inhabitants in order to provide insights that would help NGOs and government bodies to efficiently implement development plans. We believe Information Technology researchers should team up with those researchers to investigate the realities of developing areas and draw out facts that will direct the design of ICT solutions.

Empirical studies can also help to reduce the approximate (and often wrong) hypotheses that IT researchers make when designing their solutions. As researchers from Africa, we have personal experiences on how people regroup and stay very long close just for greeting each other. Unfortunately, we had a hard time convincing other researchers that the duration of such encounters is sufficient to establish reliable P2P connectivity to transfer sizeable data in an opportunistic scenario [START_REF] Ouoba | Leveraging the Cultural Model for Opportunistic Networking in sub-Saharan Africa[END_REF]. An empirical study on the average duration of contacts among people and their degree of recurrence would significantly help people realize the potential of opportunistic networking in Africa where it would be more suitable to our cultural context than it is in developed countries where it was first invented but remains unleverageable.

Return on Experiences

E-money, e-Learning or tele-medicine are praised everywhere as stornercones of ICT4D applications that are continuously helping the poor people. These praises however are based on very few successes which cannot be generalized. Indeed, most practitioners in many countries are aware that there are many more undocumented failures. When did those failure occur and why? Having answers to those questions will undoubtedly avoid repeated ICT4D design errors, and at the same time significantly reduce the waste of resources.

Return on experiences also participate in archiving the efforts of ICT4D for next generations of researchers. Identifying the landmarks already visited and the paths taken so far by other researchers may help in drawing new (and better) approaches.

Research roadmaps

Use of ICT as a vehicle for sustainable economic development cannot be effective if social conditions are not first improved. Thus, it becomes imperative to first direct ICT initiatives towards such goals. To that respect, we remind the reader that ICTs, in the context of ICT4D, are constituted by tools that facilitate communication, the processing and transmission of information and the sharing of knowledge by electronic means. In this section we suggest a classification of research priorities in terms of short, medium and long term impact needs. As McNamara has stated, experience demonstrates that there is no single solution that will work in all settings [START_REF] Mcnamara | Improving health, connecting people: The role of icts in the health sector of developing countries. A framework paper[END_REF].

Short Term Impact research: The development of Africa is challenged by deep problems such as pandemic diseases, food and water shortage, wars, and a rapid lost of our valuable heritage. We believe that ICT4D researchers should immediately tackle issues related to these problems.

Health management. Whether it is for reducing maternal death, fighting malaria or responding to HIV spread, ICT is increasingly leveraged. Indeed, ICT initiatives have demonstrated that they can make an impact on improving dissemination public health information, on enabling remote consultation, on facilitating collaboration and cooperation among practitioners (e.g., learning best practices, and worker training), on strengthening the capabilities for monitoring threats to public health and administrative systems in health care facilities [START_REF] Mcnamara | Improving health, connecting people: The role of icts in the health sector of developing countries. A framework paper[END_REF]. There are however no definite ICT answers to support all those needs, and ICT4D research in this area must be further pursued.

Food and Water. Once health is acquired, it cannot be sustained if food and water are lacking or are of bad quality. Around the world, initiatives to use ICT as an enabler of smart management of water and food resources are flourishing. In Africa, the room for improvement is still immense. ICT4D researchers can thus contribute to not only disseminate more efficiently information and advice, but also analyze and forecast food security issues for NGOs and government bodies.

Peace. For some time now, the United Nations Educational, Scientific and Cultural Organization has been advocating the use of ICT to promote peace. Thanks to the revolution in ICTs indeed, there is a real opportunity for "multilogue" to promote mutual understanding and peace. In Africa, there is yet to see ICTbased initiatives for peace building, although governance based on citizens' participation through ICT is increasingly advocated without real-world implementation [START_REF] Saleh | The impact of ict on peace, security & governace in africa[END_REF] Heritage. Finally, an urgent matter that african researchers need to look into is the preservation of the heritage. This includes the landscape, the wild life, as well as the material and immaterial legacy of African ancestors and our elders. In developed countries, national museums are taking full advantage of ICT to spark interest on their cultural heritage. In Africa, animal poaching is alarmingly threatening the Big 5 where ICT can help improve surveillance of national parks [START_REF] Mendez | Towards Automating Surveillance of National Parks: The Next Killer App of ICT4D with UAVs? Submitted to AFRICOMM[END_REF]. Recent events in Mali where Timbuktu's ancient manuscripts were saved in extremis remind us how fragile heritage in Africa is.

Medium Term Impact research:

To support and sustain short term impact research initiatives, ICT4D researchers should also allocate resources to investigate medium term issues.

Enhanced e-Agriculture. First, food security will not be fully ensured if eagriculture is not better implemented. To that end, researchers need to identify opportunities for e-agriculture for illiterate populations, in accordance with the cultural models of developing areas where competition is not necessary the first incentive.

Local e-Government. Improving local participatory governance to promote stability is a noble endeavor. Since ingredients for implementing adapted ICT approaches in developing areas are now in place, ICT4D researchers could invest into proposing ICT-based schemes. These may involve online social communities, information portals, discussion forums, etc. which are implemented with the constraints of the african context, instead of being simple copies of solutions from developed countries.

Waste management. Another research avenue that needs investigation is the management of waste, specifically electronic waste. Indeed, Africa's mounting electronic waste, or e-waste, is presenting both opportunities and problems that needs to addressed. With millions of poor consumers, Africa is importing many near end-of-life electronic devices, generating a massive waste stream. How can ICT4D researchers help with solutions for analyzing, identifying and recycling these devices before they become a serious environment issue? new Businesses of Open Source. In previous work, we have discussed how Open Source opportunities were wasted in Africa [START_REF] Ouattara/Sanon | Open Source in Africa: An Opportunity Wasted? -Why and How FLOSS Should Make Sense for Africa[END_REF]. Among those opportunities are the possibilities for increasing employment of new graduate students with opensource oriented education that will help them build start ups. Indeed, ICT4D should not only focus on fixing what is broken, it should also participate in building what has never existed.

Long-Term Impact Research: ICT4D should not be short-sighted. Nor should it fail to recognize when a field is not ready for the introduction of some new paradigm. We now discuss two important research scenarios that are widely advertised and that should be (re)thought for the long run. e-Learning. Education is and must remain a priority in Africa. Traditional classrooms may have exhausted different possibilities for welcoming everyone in acceptable conditions. In that regard, e-Learning by using ICT to assist in the exchange of knowledge can be a solution. Unfortunately, success stories told across the web are very few, as the means to implement e-Learning are often costly in a context where even traditional school faces attendance challenges. One could advocate that new learning media would spark the interest of children. Experience in some countries have shown that such an interest is not a lasting one. The problem with E-learning thus lies within its targets. In rural areas, it serves most for advertisement (and perhaps propaganda?), while in urban areas, it can actually overcome the lack of teaching personnel in some domains.

High Connectivity. Building information highways between cities in Africa will not matter if we have not previously imagined the services that will be run with it. There is "build it and they will come" strategy that can work in areas where everything is a priority. High connectivity requires big investments that most developing african developing cannot afford to make right now. However, because of the rapid pace to which Africa is confronted to globalization, there is a need for ICT4D researchers to start devising applications and scenarios for the various connectivity needs in Africa. Thus, increasing WiFi range and using whitespace technologies will make sense if we can fully take advantage of the new bandwidth that will be delivered.

Mind the Context

In this section we further discuss in details why a research roadmap for ICT4D is necessary in Africa. In developed countries, almost all areas of a single countries, i.e. villages and cities, can be treated equally when offering a new ICT service or setting up a new infrastructure, even if the investments will differ. For example, when introducing the recent 4G services, operators in Europe just planned a progressive extension of the network to cover all areas. In developing countries, however, the situation would be totally, as the priorities between urban and rural areas are very much dissimilar. We exploring in the following some ICT4D priorities in each context.

Rural areas -From survival to living

Rural areas are the most disadvantaged places in developing countries. People still practice subsistence farming to feed their families. However, traditional agriculture can no longer satisfy the needs of family members, and requires more information from outside world to increase productivity. Research on e-agriculture has thus become a priority for african rural areas. Another challenge for such areas is isolation. The lack of practicable roads and the scarce investment from network operators makes this issue persistent, although it is widely accepted that connecting rural areas with the outside world will significantly improve their livelihood, by enhancing health care, school education, farmer training, etc.

In previous work [START_REF] Ouoba | Leveraging the Cultural Model for Opportunistic Networking in sub-Saharan Africa[END_REF], we have shown how rural areas, because of the cultural model respected by inhabitants, can afford to implement ICT4D approaches based on shared technologies. Opportunistic networking is also a favorable ICT4D paradigm for bringing connectivity into such areas. Finally, ICT4D researchers should investigate the use of new free wireless technologies and the reuse/adaptation of existing open source applications.

Urban areas -Towards smart cities

Urban areas in developing countries face different challenges than their rural counterparts. In African cities, infrastructure investments have already been made, and service launches (and ceases) are witnessed every day. Because the youth attempts to identify with developed countries, ICT4D researchers have a wide range of domains where solutions adapted to existing technologies and constraints are needed. We mention here research avenues and ICT paradigms that can be leveraged to incrementally improve user experience of a connected world.

Payment. Across African cities, few inhabitants have bank accounts and credit cards. Network operators have thus seen an opportunity with mobile phones and the prepaid credit system to push for mobile banking. There seems however to be a monopoly of operators to benefit from the system since payment is done through their Integrated Service Digital Network. With the democratization of Near Field Communication (NFC) on cheap smartphones, there is ample opportunity to create new scenarios of payment.

Transport. African cities are becoming crowded and the way transport systems are working is not simplifying users' life. ICT4D can improve ticketing system, enhance the dissemination of real time information about traffic, bus hours, etc.

Culture. Young Africans in cities are increasingly unaware of the cultural wealth that surrounds them and that tourists come from far away to visit. An avenue of ICT4D research could be to propose an approach for performing a collaborative census of "must-see" tourist places, and to devise plans to spark the interest of local people.

Social Networking. While online social networking is getting adepts among african populations, Internet connectivity is not fully available anytime and anywhere to readily access worldwide sites. There is therefore a new to use alternative communication vehicles such as SMS on mobile phones to create social networks that reflect our realities and capabilities.

Discussion

To assess the scope of the AFRICOMM conference with regards to our categorization, we consider all 36 papers accepted at the 2012 session of AFRICOMM and based on their titles and abstracts we count how many papers concern one of our research avenues. Table 1 summarizes our findings. It appears that 83% of the papers are in line with our priorities of ICT4D for Africa. Only 8% focus on short-term impact research, while only also 8% provide insights with empirical studies and returns on experience. Almost 50% of papers deal with problems related to our category of long term impact research. These findings reveal that there is a need to create a synergy of research to increase the value of ICT4D papers at AFRICOMM, by introducing an equilibrium among the various topics of research that can benefit african populations.

We propose to this end, to have a theme of research every year at AFRICOMM that will allow to focus each time on a specific topic that needs attention. We could also setup a special session (or a workshop) where all ICT4D researchers could join resources and ideas to investigate a specific challenge in Africa.

Conclusion

The momentum of ICT4D research has been increasing in recent years. Research conferences across the world are publishing proceedings with numerous papers proposing every day new solutions and approaches for leveraging ICT in the development of African countries. However, we note that researchers' efforts are dispersed and no clear agenda is set for delivering solutions. Furthermore, research topics are not necessarily selected based on the real needs on the ground of developing countries. In this paper, we have discussed critical research avenues and recommended the establishment of a research theme for each edition of AFRICOMM in order to create a synergy around some challenges of ICT4D in Africa.

# of papers

Table 1 .

 1 Categories of papers presented at AFRICOMM'2012


Miguel A Olivares-Mendez
email: miguel.olivaresmendez@uni.lu

Tegawendé F Bissyandé
email: tegawende.bissyande@uni.lu

Kannan Somasundar
email: somasundar.kannan@uni.lu

Jacques Klein
email: jacques.klein@uni.lu

Holger Voos
email: holger.voos@uni.lu

Yves Le Traon
email: yves.letraon@uni.lu

The NOAH Project: Giving a Chance to Threatened Species in Africa with UAVs

Organized crime now targets one of the most precious wealth in Africa, the wild life. The most affected by the poaching are the Big 5, whose survival requires attention and efforts from everyone, in accordance to his own expertise. Just as Noah 1 was tasked to save every species from the Genesis flood, we envision the NOAH Project to (re)make natural parks as a safe haven. This endeavor requires efficient and effective surveillance which is now facilitated by the use of UAVs. We take this approach further by proposing the use of ICT algorithms to automate surveillance. The proposed intelligent system could inspect a bigger area, recognize potential threats and be manage by non-expert users, reducing the expensive resources that are needed by developing countries to address the problem.

Introduction

It takes about 10 minutes for a poacher to kill and dehorn a rhino. This period of time is too short that poachers are assured to strike continuously if significant and effective efforts are not put in place to deter them. For example, just in South Africa, two rhinos are dehorned everyday. Park rangers are indeed faced with the challenges of efficiently surveilling a territory that can be extremely large for careful and consistent patrol. South African Rangers now have eyes in the sky thanks to Air Rangers, small Unmanned Aerial Vehicles (UAVs) that are used to cover more land by providing live video feed of the terrain. While the proposed approach can be improved by using more adapted technologies that we will discuss, it opens the road for more efficient and cheaper systems using ICT knowledge.

ICT4D projects have recently proven that they can leverage high-tech products and sophisticated computer and communication algorithms to deliver solutions to the problems of developing areas. Mostly such solutions aim at addressing the cost for achieving equivalent results with traditional means. In a previous work [START_REF] Ouoba | Leveraging the Cultural Model for Opportunistic Networking in sub-Saharan Africa[END_REF] it was shown that ICT4D could also leverage directly the cultural model of Africa to adopt technologies and paradigms that may appear inadequate in developed countries where they were born. We take further this notion in this paper to advocate the use of equipments that, at first glance, can appear to be a luxury for developing countries. Examples of such equipments are the Unmanned Aerial Vehicles (UAVs) which are now getting the front position in robotics research. Miniaturization and power increase of electronic components and sensors during the last decade has greatly participated to improve the usability of UAVs while leading at the same time to significant cuts in the cost for acquiring units of such vehicles. Consequently, in developing areas, NGOs and governments can now invest in these vehicles to address specific civilian issues.

Motivation

Human brigades cannot manage the thorough surveillance of very large national parks in Africa. The huge area of the wildlife reserves and their reduced budgets make it impossible to carry surveillance strategies that are efficient for protecting various animals against poachers. UAV capabilities as well as their affordability and improved usability make them an ideal tool for surveillance tasks. Indeed, the eye in the sky gives a big advantage against illegal hunters who now manage to evade traditional surveillance methods. A UAV can inspect a big area in few minutes, when the same area would be covered in more than one hour by humans. Another point in favor of unmanned fixed wings is the reduced noise that they produce during operation flying, contrary to army helicopters, drastically limiting the possibilities for being detected by poachers. Furthermore, autonomous flight and visual detection would reduce the dependency on expert knowledge to use this kind of vehicles. One of the aim of the NOAH project is that the aircrafts could be used by the current employees of the natural parks, being a simple system that can be used by non-expert users. The autonomous detection of potential poaching situations will also allow to simplify and reduce the need for humans to supervise the functionning of the system.

Constraints

The current state of art on vision algorithms allows to make autonomous detection based in color, edge and corner detection, optical flow, shape and other approaches. The big issue of the computer vision is to manage the light changes. There are some strategies to solve this problem attached to the specific task to solve. In our case the principal problem is not this, but it also have to take into account. The poachers would like not to be detected as animals or natural parks' guards. Because of this extra complexity of this specific scenario, the color detection could not be used. The visual algorithms that must be used in this approach have to be focused in the movement detection of people or trucks and the edge and corners detection of the poachers vehicles.

This paper. We discuss in this paper the need and objectives of the NOAH project, establishing the ground for ICT4D-oriented research on UAVs. We make different contributions including :

1. a brief description of UAVs and their capabilities for fighting poaching. We also discuss already implemented approaches using UAVs to mark their deficiencies and highlight the possibilities in ICT for addressing existing challenges. 2. a discussion on the different aspects of the NOAH project. In particular we provide in-depth details on how we envision an autonomous patrol system and how ICT will help to autonomously detect poaching events and track poachers as they flee the scenes of crime.

The remainder of this paper is organized as follows. Section 2 introduces information about related work and how the battle against poaching was revolutionized by the appearance of UAVs in the parks sky. Section 3 provides details on the NOAH project and what we hope to achieve as well as the ICT means and techniques that will be leveraged to address the different challenges of autonomous surveillance of natural parks. In Section 4 we outline different open questions for a successful course of the NOAH project. These questions are noted to create a research synergy around the use of ICTs to fight for a precious heritage in Africa with a high response time and reduced costs. Finally, Section 5 concludes this work.

Unmanned Aerial vehicles and Anti poaching

In this section, we introduce UAVs for civilian use nd provide general information about their characteristics. Subsequently we present the SPOTS-Air Rangers for anti-poaching with UAVs.

Unmanned Aerial Vehicles

Each day the use of UAVs is more prolific for civil applications. Cost reductions of sensors and the availability of new prototypes that are easier to control have indeed contributed to make UAVs affordable. In parallel, the research community in sensor detection and tracking, navigation and control have recently made great advances. Nowadays most UAVs are connected to a ground station that users rely on to send real-time commands to the aircraft so as to modify its trajectory or access the feed of the on board camera. Some of them can carry a CPU on board to process in situ the information acquired by embarked sensors and modify their trajectory accordingly. Some examples are [START_REF] Olivares-Mendez | A pan-tilt camera fuzzy vision controller on an unmanned aerial vehicle[END_REF], [START_REF] Dobrokhodov | Vision-based tracking and motion estimation for moving targets using small uavs[END_REF] which use UAVs with rotary wings and vision to track objects, [START_REF] Shakernia | Landing an unmanned air vehicle: Vision based motion estimation and nonlinear control[END_REF], [START_REF] Saripalli | Vision-based autonomous landing of an unmanned aerial vehicle[END_REF], [START_REF] Saripalli | Landing a helicopter on a moving target[END_REF], [START_REF] Olivares-Mendez | Fuzzy controller for uav-landing task using 3d-position visual estimation[END_REF] which can perform autonomous landing tasks of a helicopter, or implement navigation and control systems for see-and-avoid tasks [START_REF] Olivares-Mendez | Cross-entropy optimization for scaling factors of a fuzzy controller: A see-and-avoid approach for unmanned aerial systems[END_REF], [START_REF] He | Vision-based UAV flight control and obstacle avoidance[END_REF], [START_REF] Beyeler | Vision-based control of near-obstacle flight[END_REF].

UAVs can be equipped with fixed or rotary wings. Just like their manned versions, each unmanned vehicle has its advantages and disadvantages that must by checked based on the mission to accomplish. In the specific case of UAV for anti poaching, the best solution is to use fixed wings, because they allow to cover a bigger area with less power or gas consumption. Furthermore, such wing type delivers reduced noise from the aircraft, constituting another advantage against the vertical take off and landing (VTOL).

There are today around the world numerous companies that manufacture UAVs with fixed wings. The specifications however are different from one company to another. Usually the fixed winds include one propeller that could be located at the front or the back part. The airframe of the UAV could be manufactured with different kinds of materials: some of them are flexible foam [?], fiber-reinforced polymer (FRP), glass-reinforced plastic (GRP) or balsa wood. On-board the UAV could be installed a set of sensors depending on the application. A basic set of sensors includes an inertial measure unit (IMU), GPS, pressure sensor and compas. Other sensors such as normal, thermal or omnidirectional cameras, sonars, lasers, could also be included. Depending on the application, a certain equilibrium must be reached between the propeller power, airframe material, sensor on board and endurance, stability and sensing.

SPOTS-Air Rangers

To the best of our knowledge, the only working approach that relies on UAVs for fighting against poaching is the excellent initiative conducted by SPOTS-Air Rangers [START_REF]Spots-air rangers[END_REF]. As is mentioned in their webpage, they are a "registered Section 21 Conservation Company focussed purely on the conservation and the protection of any and all threatened species". The company is using the UAVs in Africa, specifically South Africa, for the specific task of poacher detection. They use fixed wings aircrafts equipped with a high quality thermal camera, among others sensors needed to fly. The aircrafts are provided by Shadowview which is also a non profit organization providing multiple UAS solutions for conservation and civilian projects [START_REF] Shadowview | [END_REF]. The main goal of Air Rangers is to participate in the fight against poaching,through detection of potential poachers. The monitor of the capture cages with zero impact to the wildlife in the area. They also use the UAVs to track animals and thus improve the wildlife census system. Furthermore, this company applied their aircrafts for burn assessment and biomass management. Based on what we could extract from SPOTS' website, they are not using any software for autonomous detection of poaching situations, by e.g., detecting poachers, vehicles, camps and strange behaviors. No specific algorithms to increase the effectiveness of the patrol trajectories is shown in their website too.

The excellent work of this company and its project in Africa could be improved with the automation techniques that are discussed in our work and presented in this paper. Our objective is to increase the number of detected poachers, and improving the effectiveness and efficiency of autonomous flights.

Real-world Problem Statement

In this section we revisit the problems that practitioners face when trying to protect the wild life heritage of Africa. We show how human expert-controlled UAVs have shifted the challenges of natural parks, then highlight the introduced challenges as well as the shortcomings that we plan to address in the NOAH project. We discuss two dimensions of the real-world problems that could be alleviated by autonomous surveillance.

Can we assure surveillance Anytime, Anywhere? National parks in Africa cover very large bands of lands that can be hard to access in some parts. For example, the Kruger National Park covers an area of 19,480 km 2 where more than 2 rhino is killed everyday. To survey this park, rangers rely on airplane and helicopter patrols and on foot and vehicular patrols. The former is noisy, thus significantly reducing the element of surprise on poachers, while the latter is too slow and is aggravated by the vegetation which affects visibility. Furthermore, surveillance is drastically compromised during the night.

The introduction of UAVs greatly reduced the difficulties mentioned above by improving the capability for air rangers to quietly survey the areas, day and night, using cameras. Thus, with UAVs, such as the Air Ranger aircrafts, poachers can be detected before they act, and can be more efficiently tracked.

Nonetheless, to the best of our knowledge, these aircrafts can only survey parts of the national parks, i.e. only areas where the ground pilots are taking the UAVs. Furthermore, detection of poachers and poaching events is still performed by humans who visioned surveillance footage, and are thus prone to distraction and false alarms because of fatigue-caused confusion.

What response-time can the surveillance brigade guarantee? Surveillance by human brigades had the advantage of being near the crime scene when detection of poaching event or of the poachers occurs. Thus, they could readily strike. With UAVs, response-time has become critical as the people who actually "see" the poaching are located remotely and must manually use pilot the aircraft to follow the poachers until they are intercepted by park rangers.

There is therefore a need to automate the detection of poaching and the alert-system as well as the tracking of poachers to improve efficiency of antipoaching task-force by increasing the response-time. Intelligent systems would indeed directly send positions of the crime scene, and of the poachers, as well as triangulate the best locations for interception, the whole autonomously.

How many people can we afford as surveillance personnel? To cover the 19 thousands km 2 of the Kruger park, authorities must train and involve a huge number of park rangers, who put their lives in danger while patrolling. In particular, during the night, a suitable time for poaching, park rangers cannot be efficient nor can they be safe.

The Air Rangers have leveled the field by reducing the need for human patrol during the night. An Air Ranger aircraft can perform the patrol in replacement of 80 human rangers at night. Unfortunately, each of these aircrafts still requires 1 technician and 1 camera operator for its flight. Since several aircrafts are necessary to cover the entire park, a new specific personnel, with expert training on UAVs, will be required. With automation, the current human rangers employed by the parks will be able to maneuver the system seamlessly.

Autonomous Aerial Surveillance for African National Parks

We present in this section the different parts of the autonomous aerial system that we envision for patrolling huge areas of National Parks in Africa. The system aims at reducing time and cost investments while increasing the effectiveness of the current surveillance system in such areas. First, we discuss the autonomous patrol system to improve the efficiency of the surveillance task. Then, we provide insights on the visual algorithms that could be used for the detection of poachers and potential poaching situations. We highlight points that will be underlined in the open research questions of Section 4.

Autonomous Patrol System

Nowadays the huge zones of National parks in Africa is inspected, in most of the cases, by a limited number of humans patrolling in group, using ground vehicles and binoculars and facing constant danger in face of unscrupulous poachers. One potential contribution of the NOAH project is to reduce the number of people needed to cover the different parts of the Natural Parks. Furthermore, the use of the UAVs will significantly reduce the amount of time needed to check if there are potential poachers in a specific sector of the Park. Finally, from a bird view it should be easier to detect potential poaching situations. The autonomous patrol system consists in the use of any GNSS 2 signal to define a square area to patrol (Figure 1). Given two or four GNSS positions in a map an automated UAV can patrol the area in an efficient way and provide a visual feedback from the sky of inspected area. In places where such signals are lacking for navigating over the overflown area, an alternative would be to install beacons/antennas that will enable the UAVs to "know" their positions. During patrol, a supervisor who is checking the image from the onboard camera could select a specific position if any suspicious situation is detected. In this case the UAV will fly around this area to get more information. More than one position could be selected as highly suspicious areas (HSA) so that UAVs can modify their paths to focus on these areas. Then, once a poaching situation is detected the coordinates of its exact position will be stored, and the supervisor could send the command to the UAV to come back to the home position, or to stay on patrol above the crime scene, or to continue patrolling the rest of the initial selected area.

The system could flies autonomously covering a big area, being the UAV not always inside the communications range. In the case that the UAV detect autonomously a potential poaching event, it will come back suddenly inside the communications range to communicate the incident. After that it will continue patrolling from the place of the incident detected. An example of this behavior is shown in Figure 2.

The use of dedicated aircrafts to track animals, as in the SPOTS project, could be performed to prevent poaching too. Indeed, it is possible to store in a database common paths of animals in the park in order to create a map of high risk areas (HRA). Furthermore, using GPS tracker signal of animals could also help specify flight plans for UAVs which will then be performing bodyguard tasks. HSA and HRA stored information could further be used as a set of map points that require higher frequency surveillance. This is a typical example of the traveling-salesman problem and there are a set of algorithms present in the literature that could be used to improve the effectiveness of the system, including the more recent Cross-Entropy method [START_REF] Boer | A tutorial on the cross-entropy method[END_REF]. An example of a flight based on interest points (HSA and HRA) is shown in Figure 3.

Autonomous Detection and Tracking of Potential Poaching Events

The second part of the NOAH project is to provide an autonomous system to detect potential poachers, their vehicles and camps. Once one of these items is detected the system will send an alarm signal to the ground/mobile station. The system will furthermore be able to track potential poachers autonomously if the aircraft is requested to do so. The best way to perform an autonomous detection of such kind of situation is to rely on a camera.

Advances in vision algorithms in the last decade have pushed cameras in front as the most suitable sensor in robotics. A camera gives a wide range view of the environment of the robot with a reduced equipment. Furthermore, similarities with the human vision sensor gives an advantage that information obtained from this sensor can be easily understood and analyzed, unlike other sensors such as sonars and lasers. The literature already includes various state-of-the art algorithms that can be easily adapted to suit the specific needs of the NOAH project. In general, poachers are more likely to kill animals during the night when animals are more vulnerable and ranger brigade cannot be efficient. For this reason the aircrafts in the NOAH project must integrate a thermal camera for the visual detection. With this kind of camera, it is easy to detect, recognize and track humans, vehicles or camps which emit thermal energy.

For the visual detection of object shapes, most of the algorithms are based on the RANSAC paradigm [START_REF] Bolles | A ransac-based approach to model fitting and its application to finding cylinders in range data[END_REF] and the Hough transform [START_REF] Hough | Method and means for recognizing complex patterns[END_REF][START_REF] Duda | Use of the hough transformation to detect lines and curves in pictures[END_REF], and the generalization by Ballard of Hough transform for the detection of arbitrary shapes [START_REF] Ballard | Readings in computer vision: issues, problems, principles, and paradigms. chapter Generalizing the hough transform to detect arbitrary shapes[END_REF]. An issue with these techniques is the high computational cost that they imply. A common solution in computer vision is then to use one or more edge detection algorithm to reduce the image information to be processed by the shape detection algorithm. The most used algorithms for the edge detection are the Robert's Cross operator [START_REF] Chickanosky | Wreath products for edge detection[END_REF], Sobel operator [START_REF] Ying-Dong | A fast subpixel edge detection method using sobel-zernike moments operator[END_REF], laplacian of gaussian filter [START_REF] Kamgar-Parsi | Optimally isotropic laplacian operator[END_REF] and the Canny's edge detection algorithm [START_REF] Ding | On the canny edge detector[END_REF]. The latter is the one that is selected in most real time applications such as those that will be implemented in the NOAH project.

Use of edge detection increases the possibilities of detecting vehicles, camps (tent edges) and rifles, since straight lines reinforce edge and border detection. Furthermore, it is a known fact, that in most of the cases, objects with straight lines are productions of human activities, because there are very few cases of that sort in nature. Finally, detection of poacher is based on a simple difference between humans and animals: animals have two more legs than humans that can be easily differentiated on a thermal image acquisition.

Another important part of the NOAH project is to develop an easy human machine interface (HMI) so that the system could be used by non technician users. The different autonomous modules that will be developed will make easier the selection between one and the other by the HMI. The HMI will then give all the information needed for the user in real time as well as visual shortcuts to change to a new task or to modify the trajectory of the aircraft, making it the next best weapon that will be provided to park rangers.

Open Research Questions

The NOAH project envisions to fully automate the surveillance of parks to fight against poaching but also to participate in medical care of sick animals. However, to successfully complete this endeavor, there are various ICT research avenues that must be undertaken by a research task force that includes researchers from IT as well as veterinarians, rangers, etc.

Roadmaps

In this section we enumerate a few ICT research questions for the NOAH project: Machine learning. For automating the recognition of poaching event, and of poachers about to act or after the crime, there is a need to train UAVs. With machine learning, algorithms can be developed to help UAVs autonomously recognize unusual events or aspects in the park. Furthermore, ad hoc heuristics must be implemented to empower UAVs to:

-differentiate between humans (e.g., between a hunter/poacher and a hiker/tourist) -differentiate a sick animal from a resting one Indeed, while vision detection algorithms can help highlight anomalies, only machine learning will allow us to reduce the number of false alarms, and thus focus the allocated resources into the efficiency of a smart autonomous antipoaching system.

Global Positioning. Good GPS coverage is not guaranteed in many parts of Africa. Yet, for UAVs to be able to alert human rangers on ongoing poaching events, they need to be able to provide the positions of the event so that the nearest brigade can move on site. To overcome the challenge of poor GPS coverage, we could setup and hide beacons in strategic places of the parks allowing UAVs to triangulate and confirm locally-comprehensive positions.

Air-Ground Liaison. Finally, a challenge remains in the way ground stations communicate with UAVs when those go too far to patrol autonomously and need to report a serious event without disrupting the course of their patrol. This challenge can be overcome by the use of long-range WiFi which is commonly used for low-cost, unregulated point-to-point connections. There is also a possibility to use the operator network to send SMS with coordinates which will be extracted and used by applications in a ranger's smartphone.

Reuse of Domain-specific knowledge

In the course of discussion for the kick-off of the NOAH project, we agreed that ICT alone, even with the most sophisticated techniques, cannot overcome the challenges of anti-poaching systems. There is a need to try to leverage knowledge from the context of developing regions and from the field of animal behavior. For example, simple heuristics to drive the autonomous patrol of UAVs can include taking into account details such as:

-the convergence of hyenas: these animals are known to be among the first to notice that another animal, even a much stronger one, is sick or in danger. If UAVs can spot such a convergence, they have an indication of where to focus patrol tasks. -the divergence of animal herds: in the wild, animals usually move in groups.

When a danger (e.g., a poacher) is flared, there is a general stamped which is more easily recognized by vision algorithms.

Concluding remarks

Animal poaching is threatening various species in Africa, even those that are living in national parks. With the advent of UAVs for civil use, the fight against poachers has gained a new breath. With the NOAH project we plan to automate patrol with UAVs so as to cover a bigger area, require less expert personnel, and reduce costs while delivering effective detection of poaching events. In this position paper we have motivated the NOAH project and discussed how it will serve to protect Africa's wild life heritage. Numerous challenges for a successful completion of the project were enumerated, and we have identified ICT research roadmaps that will be followed in the course of the project. With this paper, we hope to create a synergy of ICT research around a real-world development problem that is poaching.

Fig. 1 .

 1 Fig. 1. Autonmous patrol flight plan -the entire area will be inspected in one round

Fig. 2 .

 2 Fig. 2. Covering a extended area the UAV come back to report an incident when the detection has done out of range

Fig. 3 .

 3 Fig. 3. Autonomous patrol focus on high risk areas (HRA) and high suspicious areas (HSA)

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