Semantic Modeling for Group Formation

Group formation has always been a subject of interest in collaborative learning research. As it is concerned with assigning learners to the groups that maximize their benefits, computer-supported group formation can be viewed in this context as an active personalization for the individual as an entity within the group. While applying this personalization to all students in the class can cause conflicts due to the differences of needs and interests between the individuals, negotiating the allocations to groups to reach consensus can be a very challenging task. The automated process of grouping students while preserving the individual’s personalization needs to be supported by an appropriate learner model. In this paper, we propose a semantic learner model based on the Friend of Friend (FOAF) ontology, a vocabulary for mapping social networks. We discuss the model as we analyse the different types of groups and the learners’ features that need to be modeled for each of these types

Towards a semantic modeling of learners for social networks

The Friend of a Friend (FOAF) ontology is a vocabulary for mapping social networks. In this paper we propose an extension to FOAF in order to allow it to model learners and their social networks. We analyse FOAF alongside different learner modeling standards and specifications, and based on this analysis we introduce a taxonomy of the different features found in those models. We then compare the learner models and FOAF against the taxonomy to see how their characteristics have been shaped by their purpose. Based on this we propose extensions to FOAF in order to produce a learner model that is capable of forming the basis of a semantic social network.<br/

Partisipasi Masyarakat dalam Sistem Pengelolaan Sampah di Tpa Sukoharjo Kabupaten Pati

Kehadiran Tempat Pengelolaan Akhir Sampah (TPA) di Desa Sukoharjo, Kecamatan Margorejo, Kabupeten Pati belum bisa dirasakan kontribusi sosialnya oleh warga sekitar.Beberapa program pengelolaan sampah yang diselenggarakan oleh pengelola TPA belum pernah melibatkan masyarakat sekitar, padahal hal ini penting agar masyarakat memperoleh pengetahuan dan bisa termotivasi untuk melakukan pengelolaan sampah dalam komunitas mereka. Pengelolaan sampah yang berbasis komunitas dengan mensinergiskan dengan system pengelolaan sampah di TPA merupakan model pengelolaan sampah yang cukup efektif yang bisa dilakukan di wilayah ini.Model pengelolaan sampah yang semacam ini mensyaratkan tumbuhnya kesadaran dan partisipasi aktif warga untuk turut mengelola sampah di lingkungan mereka.Hal ini dimaksudkan agar muncul kelompok warga yang peduli sampah dan berkeinginan untuk mengelolanya, sehingga pengelolaan sampah dapat berkelanjutan. Di samping itu, juga mensyaratkan adanya jejaring kerjasama dengan TPA dan lembaga lain dalam pengelolaan sampah.Kegiatan ini dilaksanakan dengan dua metode kegiatan, yakni Focus Group Discussion (FGD) dan Sosialisasi.FGD dilakukan dalam 2 tahap yakni FGD I yang bertujuan untuk menggali persoalan-persoalan yang dihadap masyarakat terkait dengan pengelolaan sampah agar masyarakat dapat memahami dan menyadari persoalan mereka sehari-hari dan FGD II yang bertujuan untuk menggali dan memunculkan peran serta dan partisipasi aktif dari masyarakat untuk mengelola sampah secara berkelanjutan.Sosialisasi dilakukan dengan memberikan informasi kepada masyarakat tentang upaya pengelolaan sampah yang berbasis komunitas.Kegiatan ini berlangsung dengan hasil yang baik, sebab kehadiran, partisipasi, dan antusiasme warga dalam mendukung kegiatan ini cukup tinggi.Tetapi singkatnya waktu pelaksanaan dan kurang dilibatkannya perempuan menjadi kendala dari kegiatan ini.Meski demikian, dari kegiatan ini diharapkan tumbuh kesadaran warga untuk mengelola sampah di lingkungan mereka secara partisipatif

Karakteristik Kimia dan Fisika Semen Pozolan Kapur yang Diperkaya Silika Abu Sekam Padi

Development of infrastructures intensively in the last decades has increased the demand for building materials, such as cement. This also causes the prices of Portland Cement, the most common type of cements has also increased and sometimes it is difficult to find it in the markets. Another type of cement namely Lime Pozolan Cement (SPK) may be used to substitute for Portland Cement for building construction which receives relatively low loads. The SPK is produced from pozolan materials and lime without heating process. The common pozolan materials used is tras. This research is aimed to investigate chemical and physical characteristics of the SPK enriched with silica of rice hull ash (ASP). The ASP is intended to reduce the use of trace as the source of silica. Methods used included experiments and testing. Supplements of the ASP in the SPK were varied at the levels of 0, 5, 10, 15, and 20% (w/w). The results of the research indicated that without ASP supplement (control treatment), SiO2 contents was 53.94%. By 5 to 20% ASP supplement increased SiO2 content to 59.54 - 65.87%. However SO3 content was reduced from 3.43% to 2.04 - 1.11% and MgO content from 2.36% to 2.29 - 1.64%. Furthermore, as the ASP supplement in SPK increased the compresive strength of concrete samples also increased, except at 15% and 20% ASP supplement after 21 and 28 days storage of the samples. Therefore, the optimum ASP supplement in SPK in this study was 15% with compressive strength of 103 x105 kg/m2 after 21 days storage and 128 x105 kg/m2 after 28 days storage

Proximate analysis of fibres of grain sorghum, pearl millet and sesame residues and their fractions in Gadarif State, Sudan

&nbsp;&nbsp; &nbsp;Proximate analysis and fibres were determined in different fractions of sorghum stover [Sorghum bicolor (L.) Moench.] (Arfaa gadamac variety), sesame straw (Sesamum indicum L.) and millet straw [Pennisetum typhoides (Burm.)] with roots or without roots in Gadarif State, Sudan, in 2007. The plants were divided into upper, middle and lower parts and leaves. There were great variations in the composition of the straws and their fractions and they had low crude protein (CP) and high fibre content. Sorghum stover had the highest CP, ash and nitrogen free extract (NFE) and the lowest crude fibres (CF) and modified acid detergent fibres (MADF) among the crop residues. Millet straw had the lowest ether extract (EE) and NFE and the highest neutral detergent fibres (NDF) and MADF. Crude fibre was not significantly (P&gt;0.05) different in millet and sesame straws. Leaves had the highest CP and lowest fibre content. Crop residues nutritive value declined from the top to the bottom of the &nbsp;plants. &nbsp; &nbsp;&nbsp; تم تحديد التحليل التقريبي والألياف المختلفة في الأجزاء المختلفة من تبن الذرة الرفيعة&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ( صنف أرفع قدمك) وتبن السمسم وتبن الدخن بجذور او بدون جذور ، ولاية القضارف ، السودان. قسمت النباتات الى أجزاء عليا ، وـوسطى وسفلي وأوراق كاملة. وجدت اختلافات كبيرة في تركيب الأتبان واجزائها وكانت منخفضة البروتين الخام ومرتفعة الألياف. كان لتبن الذرة أعلى البروتين الخام والرماد والجزء الخالي من النتروجين وأقل الألياف الخام والألياف الذائبة في الحامض المعدلة بين أتبان المحاصيل. وكان لتبن الدخن أقل الدهون والجزء الخالي من النتروجين وأعلى الألياف الذائبة في المنظف والألياف الذائبة في الحامض المعدلة. تقاربت الألياف الخام&nbsp; لتبني الدخن والسمسم ولم تختلف معنويا. الأوراق بها أعلى البروتين الخام وأقل الألياف. انخفضت القيمة الغذائية للأتبان من أعلى إلى أسفل.&nbsp;&nbsp;&nbsp;&nbsp; &nbsp; &nbsp;&nbsp;&nbsp;&nbsp

CO2 laser beam welding of AM60 magnesium-based alloy

The authors are grateful to FONDERIE MESSIER HONSEL group that provided the as-cast magnesium alloy workpieces. The authors would like also to acknowledge the technical support of Dr. Moraru of the LSIS Laboratory-Arts et Métiers ParisTech-Aix En Provence-France.Magnesium alloys have a 33% lower density than aluminum alloys, whereas they exhibit the same mechanical characteristics. Their application increases in many economic sectors, in particular, in aeronautic and automotive industries. Nevertheless, their assembly with welding techniques still remains to be developed. In this paper, we present a CO2 laser welding investigation of AM60 magnesium-based alloy. Welding parameters range is determinate for the joining of 3 mm thickness sheets. The effects of process parameters including beam power, welding speed, focusing position, and shielding gas flow are studied. Experimental results show that the main parameters that determine the weld quality are the laser beam power, the welding speed, and the shielding gas flow. The focal point position has a minor effect on weld quality, however, it has an influence on melting zone width. For optimized welding parameters, metallurgical observations show that after laser welding of AM60 alloy dendritic microstructure is observed on melting zone after high solidification rate. A small heat affected zone is also detected. Finally, hardness tests indicate that microhardness of the weld is higher than that of base metal

Dynamic model of gene regulation for the lac operon

Gene regulatory network is a collection of DNA which interact with each other and with other matter in the cell. The lac operon is an example of a relatively simple genetic network and is one of the best-studied structures in the Escherichia coli bacteria. In this work we consider a deterministic model of the lac operon with a noise term, representing the stochastic nature of the regulation. The model is written in terms of a system of simultaneous first order differential equations with delays. We investigate an analytical and numerical solution and analyse the range of values for the parameters corresponding to a stable solution

Short Kloosterman Sums for Polynomials over Finite Fields

This is a preprint of an article published in the Canadian Journal of Mathematics, 55 (2003), pp.225-246.We extend to the setting of polynomials over a finite field certain estimates for short Kloosterman sums originally due to Karatsuba. Our estimates are then used to establish some uniformity of distribution results in the ring Fq[x]/M(x) for collections of polynomials either of the form f−1g−1 or of the form f−1g−1 + afg, where f and g are polynomials coprime to M and of very small degree relative to M, and a is an arbitrary polynomial. We also give estimates for short Kloosterman sums where the summation runs over products of two irreducible polynomials of small degree. It is likely that this result can be used to give an improvement of the Brun-Titchmarsh theorem for polynomials over finite fields