Discarge compilation from The Global River Discharge (RivDIS) Project

The Global River Discharge (RivDIS) data set contains monthly discharge measurements for 1018 stations located throughout the world. The period of record varies widely from station to station, with a mean of 21.5 years. These data were digitized from published UNESCO archives by Charles Voromarty, Balaze Fekete, and B.A. Tucker of the Complex Systems Research Center (CSRC) at the University of New Hampshire. River discharge is typically measured through the use of a rating curve that relates local water level height to discharge. This rating curve is used to estimate discharge from the observed water level. The rating curves are periodically rechecked and recalibrated through on-site measurement of discharge and river stage.

革命後チュニジアの政治的不安定

アラブ革命の震源地となったチュニジアでは、2011年1月の政変によってベン・アリー体制が崩壊したのち、イスラーム政党「ナフダ運動」を中心とする新連立政権が誕生した。しかし、ナフダ政権はその後閣僚の辞任、野党政治家の暗殺、サラフィー主義の台頭などの問題に見舞われ、早くも危機に直面している。ナフダ政権の不安定は、よく言われるような、「世俗主義」対「イスラーム主義」の対立が政治と社会を二分する状況に起因するというよりは、チュニジアにおける政党政治の成熟度と関わっている。すなわち、反体制の社会運動として始まり、30年の非合法活動を経て、革命によって一躍与党となったナフダの背景を考慮した時、同党の不安定性は、新興民主主義国の政党に特有の問題として浮かび上がってくる。本論では、ナフダのどのような特性が政権不安定へとつながっているのかを指摘し、構造上の問題が政策決定上の障害として表れた事例として、2013年2月のジバーリー首相辞任の過程を分析する。

「アラブの春」後の移行期過程 -- 帰結を分ける諸要因

Diverging outcomes are unfolding in the post-Arab Uprising countries' transitional processes. In January 2014, Tunisia successfully adopted a new constitution based on a consensus of the opposing political parties and factions. In contrast, Egypt abolished one constitution and hastily instituted another in a time span of slightly more than a year. Yemen has announced the final document of the National Dialogue Conference in the same month. Libyans finally voted for the long awaited and disputed elections of the Constitutional Drafting Committee in February 2014. The paper picks up three factors which seem to be influential in determining the modality of transitional political process in the four Post-Arab spring countries. The first is the initial conditions of the transitional politics.. Differences in the way the previous regimes collapsed are analyzed to illuminate the continuity and break of the ruling institutions and state apparatus. The second factor is the type of the interim government. In line with Shain and Linz typology, provisional, power-sharing, caretaker, and international interim government models are applied to clarify the types of interim governments in each four countries' different phases in transitional politics. The third is the "rules of the game," particularly those pertaining to the constitutional process. Who set what kind of rules and how are to be considered in each of four countries and possible influences of each set of the rules of the game to the diverging results of the transitional politics are considered.

Sustainability of irrigated farming systems in a Tunisian region: A recursive stochastic programming analysis

The aim of this study was to evaluate the sustainability of farm irrigation systems in the Cébalat district in northern Tunisia. It addressed the challenging topic of sustainable agriculture through a bio-economic approach linking a biophysical model to an economic optimisation model. A crop growth simulation model (CropSyst) was used to build a database to determine the relationships between agricultural practices, crop yields and environmental effects (salt accumulation in soil and leaching of nitrates) in a context of high climatic variability. The database was then fed into a recursive stochastic model set for a 10-year plan that allowed analysing the effects of cropping patterns on farm income, salt accumulation and nitrate leaching. We assumed that the long-term sustainability of soil productivity might be in conflict with farm profitability in the short-term. Assuming a discount rate of 10% (for the base scenario), the model closely reproduced the current system and allowed to predict the degradation of soil quality due to long-term salt accumulation. The results showed that there was more accumulation of salt in the soil for the base scenario than for the alternative scenario (discount rate of 0%). This result was induced by applying a higher quantity of water per hectare for the alternative as compared to a base scenario. The results also showed that nitrogen leaching is very low for the two discount rates and all climate scenarios. In conclusion, the results show that the difference in farm income between the alternative and base scenarios increases over time to attain 45% after 10 years.

Business model with discount incentive in a P2P-cloud multimedia streaming system

Today P2P faces two important challenges: design of mechanisms to encourage users' collaboration in multimedia live streaming services; design of reliable algorithms with QoS provision, to encourage the multimedia providers employ the P2P topology in commercial live streaming systems. We believe that these two challenges are tightly-related and there is much to be done with respect. This paper analyzes the effect of user behavior in a multi-tree P2P overlay and describes a business model based on monetary discount as incentive in a P2P-Cloud multimedia streaming system. We believe a discount model can boost up users' cooperation and loyalty and enhance the overall system integrity and performance. Moreover the model bounds the constraints for a provider's revenue and cost if the P2P system is leveraged on a cloud infrastructure. Our case study shows that a streaming system provider can establish or adapt his business model by applying the described bounds to achieve a good discount-revenue trade-off and promote the system to the users.

Incorporating proactivity to context-aware recommender systems for e-learning

Recommender systems in e-learning have proved to be powerful tools to find suitable educational material during the learning experience. But traditional user request-response patterns are still being used to generate these recommendations. By including contextual information derived from the use of ubiquitous learning environments, the possibility of incorporating proactivity to the recommendation process has arisen. In this paper we describe methods to push proactive recommendations to e-learning systems users when the situation is appropriate without being needed their explicit request. As a result, interesting learning objects can be recommended attending to the user?s needs in every situation. The impact of this proactive recommendations generated have been evaluated among teachers and scientists in a real e-learning social network called Virtual Science Hub related to the GLOBAL excursion European project. Outcomes indicate that the methods proposed are valid to generate such kind of recommendations in e-learning scenarios. The results also show that the users' perceived appropriateness of having proactive recommendations is high.