MWAND: A New Early Termination Algorithm for Fast and Efficient Query Evaluation

Nowadays, current information systems are so large and maintain huge amount of data. At every time, they process millions of documents and millions of queries. In order to choose the most important responses from this amount of data, it is well to apply what is so called early termination algorithms. These ones attempt to extract the Top-K documents according to a specified increasing monotone function. The principal idea behind is to reach and score the most significant less number of documents. So, they avoid fully processing the whole documents. WAND algorithm is at the state of the art in this area. Despite it is efficient, it is missing effectiveness and precision. In this paper, we propose two contributions, the principal proposal is a new early termination algorithm based on WAND approach, we call it MWAND (Modified WAND). This one is faster and more precise than the first. It has the ability to avoid unnecessary WAND steps. In this work, we integrate a tree structure as an index into WAND and we add new levels in query processing. In the second contribution, we define new fine metrics to ameliorate the evaluation of the retrieved information. The experimental results on real datasets show that MWAND is more efficient than the WAND approach

Optimum Dispersion Parameters of Carbon Nanotubes: Concrete Strength by Response Surface Methodologies

"This paper implements Response Surface Methodologies (RSM) techniques to illustrate the maximum carbon nanotubes (CNTs)-concrete mechanical properties responses to the length, weight fraction and treatment variables. Mixes with different CNTs’ content were prepared and tested for flexure, compression and tension. RSM analysis showed that the highest effect on the strengths was due to the CNTs’ content variable. The analysis showed that a weight fraction of 0.3 wt.% of non-treated CNTs is required to achieve the maximum flexural, compressive and tensile strengths in a batch as per the predicted model. RSM analysis also showed that maximum flexural strength will be obtained by using 0.2 wt. % non-treated long CNTs, 0.25 wt. % non-treated short CNTs and 0.03 wt. % treated long CNTs, respectively.

Marital crises from the point of view of primary school teachers in the state of Laghouat

تهدف الدراسة الحالية الى التعرف على الأزمات الزوجية من وجهة نظر معلمات الطور الإبتدائي، وقد أجريت الدراسة على عينة قوامها (40) معلمة تمَّ إختيارهم بطريقة قصديه، حيث إعتمدت الباحثة على المنهج الوصفي مستخدمة في ذلك مقياس كشف الأزمة الزوجية، كما تم إستخدام الأساليب الإحصائية المتمثلة في المقارنة الطرفية وألفا كرونباخ لقياس صدق وثبات المقياس، والمتوسط الحسابي والمتوسط الفرضي وإختبار (T) لدلالة الفروق، وبعد المعالجة الإحصائية جاءت النتائج على النحو التالي : - أن مستوى الأزمات الزوجية لدى معلمات المرحلة الإبتدائية منخفض، ولا توجد فروق دالة إحصائيا بين المعلمات في المرحلة الإبتدائية تعزى لمتغير العمر، كما لا توجد فروق دالة إحصائيا بين المعلمات في المرحلة الإبتدائية تعزى لمتغير السكن.The current study aims to identify marital crises from the point of view of the teachers of the primary stage, it was conducted on a sample of (40) teachers who were chosen in an intentional way. The researcher relied on the descriptive approach using the marital crisis detection scale, and statistical methods represented in the peripheral comparison and Cronbach’s alpha to measure the validity and reliability of the scale, as well as the arithmetic mean, the hypothetical mean and the (T) test for significance of differences. After the statistical analysis of the data, we reached the following results The level of couple crises among female teachers at the primary stage is weak due to the variable of age, and there are no statistically significant differences between them due to the variable of housing

Climatic Drivers of Potential Hazards in Mediterranean Coasts

This paper studies climatic drivers (air and water temperature, precipitation rates, river discharge, sea level and storm patterns) in four Mediterranean regions: the Catalan-Valencia Coast (Spain), the Oran (Algeria) and Gabe`s (Tunisia) Gulfs and the western Nile Delta (Egypt). The paper also considers the potential hazards that these drivers can induce. It first analyses climatic trends in the drivers, taking into account the available time series of recorded and simulated meteo-oceanographic data from different sources. Next, it presents the general framework to assess biogeophysical hazards (flooding, erosion, droughts and water quality), followed by a simple and yet robust evaluation of those hazards for the four studied coastal sites. Assuming climate change projections under different scenarios and considering the observed trends in drivers, the resulting erosion rates due to sea-level rise and wave storm effects have been estimated. The Nile and Ebro Deltas, together with the Oran Gulf, are more vulnerable than the Gulfs of Valencia and Gabe`s. Regarding water quality in terms of (a) precipitation and dissolved oxygen in the water column and (b) sea surface temperature, the results show that the most vulnerable zones for the projected conditions (a) are the Gulfs of Oran, Valencia and Gabe`s, while the Nile Delta is the region where the decrease in water quality will be less pronounced. For the projected conditions (b), the most vulnerable zone is the Ebro Delta, while the impact in the other three cases will be smaller and of comparable magnitude. Finally, the overall future impact of these hazards (associated to climatic change) in the four sites is discussed in comparative terms, deriving some conclusions

Synthesis of Calcium Nitrate Self-Healing Microcapsules Using Aerosol OT Hexane Solution for Cementitious Materials

Calcium nitrate synthesis of in urea-formaldehyde shell has recently been used to produce self-healing microcapsules for construction applications. The original synthesis was based on water-in-oil emulsion with sulfonic acid as fundamental ingredient of the oil (continuous) phase. It has been modified herein by changing the composition of the continuous (oil) phase by mixing anionic surfactant, Aerosol OT (AOT) with hexane to prepare the solution while keeping the aqueous phase unchanged. The submicron refined calcium nitrate microcapsules. In order to characterize the microcapsules encapsulated using the aforementioned, procedure, a Scanning Electron Microscopy (SEM) was utilized. The obtained microcapsules had satisfactory diameter and shell thickness. To assess the effect of the prepared microcapsules on the compressive and flexural strengths, mortar mixes containing 75% microcapsules (by weight of cement), as an introductory dosage, were made. It has been demonstrated that incorporating the self-healing microcapsules prepared using the procedure suggested in this study did not cause significant reductions in the mortar samples' strengths. Hence, the encapsulation methodology presented here may be utilized to investigate their self-healing efficiency in cementitious materials

Adaptive selection of radio access technology for the data transport depending on context

Les travaux développés dans cette thèse ont pour cadre général la mise en œuvre d’approches adaptatives permettant de faire évoluer la gestion du réseau en migrant d’une vue "centrée réseau" où l’on se contentait uniquement des paramètres issus du réseau lui-même, vers une vue "centrée utilisateur". Plus particulièrement, ces travaux se sont focalisés sur un des composants principaux de l’ensemble de la chaîne de traitement et de transport, celui de la sélection de la meilleure interface réseau embarquée dans le terminal mobile, l’objectif étant de répondre au mieux aux contraintes imposées par l’environnement. Ces travaux reposent sur une approche décisionnelle dynamique tenant compte de changements dans les paramètres réseaux et des besoins et préférences des utilisateurs au regard des services qui leur sont proposés. En effet, dans l’environnement actuel, se caractérisant par une multiplicité de technologies, d’applications et d’utilisateurs, les terminaux mobiles sont équipés de plusieurs interfaces réseaux. Ces derniers donnent ainsi la possibilité aux utilisateurs de pouvoir basculer dynamiquement d’une interface à une autre dans l’objectif d’assurer une connexion satisfaisant le mieux possible leurs besoins en termes de services en tout lieu, à tout moment et de la meilleure manière possible (ABC, Always Best Connected). Les approches mises en œuvre dans le cadre de la thèse ont permis d’associer simultanément chaque flux d’application à l’interface la plus appropriée de manière à optimiser les performances globales du système. Ainsi, ces travaux ont mené à la proposition d’approches hybrides ayant pour cadre de départ la technique TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) et en y intégrant des modèles issus de la théorie des fonctions de croyance. Pour l’association flux/interface, une proposition basée sur des algorithmes bio-inspirés a été faite dans le cadre de ces travaux. Les résultats obtenus, à la fois par simulation et sur un cas d’usage réel en lien avec le domaine de la santé connectée, ont montré l’efficacité des approches proposéesThe work developed in this dissertation has as a general framework the implementation of adaptive user-centric approaches for network interface selection (NIS) and flow/interface association (FIA) in Heterogeneous Wireless Networks (HWNs). The NIS mechanism relies on a dynamic decision approach that considers the change in networks’ parameters and users’ needs and preferences for their current applications. In a heterogeneous environment, the mobile terminals that are equipped with multiple network interfaces provide the possibility for mobile end-users to switch among available network interfaces and select the one that best fulfills their needs anywhere at any time which is known as Always Best Connected (ABC). The approaches proposed in this thesis allowed to associate simultaneously each application flow to its suitable interface in a way that best maximizes the global system performance. This work has led to the proposal of hybrid approaches originating from TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) and integrating models from the belief functions theory for the NIS. Concerning the FIA, a proposal based on bio-inspired algorithms was made as part of this work. Experimental results based on synthetic datasets and an experimental test bed for health monitoring showed the effectiveness of the proposed approache

Belief functions in telecommunications and network technologies: an overview

In the last few years, evidence theory, also known as Dempster-Shafer theory or belief functions theory, have received growing attention in many fields such as artificial intelligence, computer vision, telecommunications and networks, robotics, and finance. This is due to the fact that imperfect information permeates the real-world applications, and as a result, it must be incorporated into any information system that aims to provide a complete and accurate model of the real world. Although, it is in an early stage of development relative to classical probability theory, evidence theory has proved to be particularly useful to represent and reason with imperfect information in a wide range of real-world applications. In such cases, evidence theory provides a flexible framework for handling and mining uncertainty and imprecision as well as combining evidence obtained from multiple sources and modeling the conflict between them. The purpose of this paper is threefold. First, it introduces the basics of the belief functions theory with emphasis on the transferable belief model. Second, it provides a practical case study to show how the belief functions theory was used in a real network application, thereby providing guidelines for how the evidence theory may be used in telecommunications and networks. Lastly, it surveys and discusses a number of examples of applications of the evidence theory in telecommunications and network technologies