Correlation Clustering Based Coalition Formation For Multi-Robot Task Allocation

In this paper, we study the multi-robot task allocation problem where a group of robots needs to be allocated to a set of tasks so that the tasks can be finished optimally. One task may need more than one robot to finish it. Therefore the robots need to form coalitions to complete these tasks. Multi-robot coalition formation for task allocation is a well-known NP-hard problem. To solve this problem, we use a linear-programming based graph partitioning approach along with a region growing strategy which allocates (near) optimal robot coalitions to tasks in a negligible amount of time. Our proposed algorithm is fast (only taking 230 secs. for 100 robots and 10 tasks) and it also finds a near-optimal solution (up to 97.66% of the optimal). We have empirically demonstrated that the proposed approach in this paper always finds a solution which is closer (up to 9.1 times) to the optimal solution than a theoretical worst-case bound proved in an earlier work

Matchings with externalities and attitudes

Two-sided matchings are an important theoretical tool used to model markets and social interactions. In many real-life problems the utility of an agent is influenced not only by their own choices, but also by the choices that other agents make. Such an influence is called an externality. Whereas fully expressive representations of externalities in matchings require exponential space, in this paper we propose a compact model of externalities, in which the influence of a match on each agent is computed additively. Under this framework, we analyze many-to-many matchings and one-to-one matchings where agents take different attitudes when reasoning about the actions of others. In particular, we study optimistic, neutral and pessimistic attitudes and provide both computational hardness results and polynomial-time algorithms for computing stable outcomes

Machinability of natural fibre reinforced polymeric composites

From an industrial perspective, there are some issues with the machinability of synthetic fibre/polymer composites (glass fibres), including hole accuracy, delamination, appearance and energy consumption. These are mainly due to the abrasive nature of the synthetic fibres. Introducing natural fibres as reinforcement to the polymeric composite may overcome some of these issues, as natural fibres have less abrasive effects compared to synthetic fibres. Moreover, natural fibres are becoming an attractive candidate to replace synthetic fibres for several applications. In the current study, epoxy composites based on date palm fibres were developed. The interfacial adhesion of the date palm fibres with the matrix is first evaluated for optimum fibre diameter and NaOH concentrations through a single fibre pull out test. With regards to machinability of the composite, drilling experiments were conducted on neat epoxy, glass/epoxy and date/epoxy composites. A new dynamometer was developed and fabricated locally. The influence of the cutting speed, feed rate and drill diameter on the machinability of the composites was evaluated in terms of hole accuracy, inner and outer delamination, specific cutting pressure and machining power. Scanning electron microscopy and optical microscopy were used to examine the damaged features in the experiments of interfacial adhesion and machinability. The ANOVA approach was used to identify the most effective parameters on the machinability of the composites. The results revealed that NaOH concentration in the treatment solution affects the strength and the interfacial adhesion of the fibre with the matrix. Six per cent NaOH concentration is the optimum concentration in which there was less damage to the strength of the fibre and enhancement to the interfacial adhesion of the fibre with the matrix. Tensile properties of the epoxy were found to be improved with the addition of either natural or synthetic fibres. However, glass fibres improved the tensile strength of the epoxy significantly compared to the date palm fibre, even though glass fibres suffered from detachment and a pull out mechanism during loading conditions. In the drilling process for all materials, there were three regions observed: inner, intermediate and outer. The thrust and torque behaviour with the drilling time was divided into these three regions. The peak values were observed in the intermediate regions in which the shears occurred at a higher level with the thrust force. The presence of glass fibres in the epoxy composites assisted in reducing crack propagation at the inlet regions; however, it highly deteriorated the outlet region, as detachments and a decomposition mechanism were observed. For neat epoxy, cracks and fractures were the main damage features noticed. Meanwhile, the presence of date palm fibre in the epoxy improved the machinability of the composites, as it required similar values of torque and thrust to that of neat epoxy, while glass fibres needed more power. Date palm fibres assisted in reducing cracks in the inner and outer regions of the hole of the composites, even though pull out and detachments were observed. Hole accuracy is highly controlled by the operating parameters, as an increase in the drilling speed and feed rate resulted in high error percentage of hole accuracy for all materials. The addition of date palm fibres had a lower error percentage to the hole accuracy compared to the glass fibres, and this was mainly due to the abrasive nature of the glass fibres. Micrographs show fragmentations and pull out of fibres for neat epoxy and glass/epoxy composites, respectively. Meanwhile, date/epoxy exhibited fragmentation at the edge of the holes, which was considered less damage compared to the glass/epoxy. The specific cutting pressure reduced significantly with an increase in the feed rate. However, there was no clear effect from the drilling speeds on the specific cutting pressure. The most influential parameter was the drill diameter, as there was a large increase in the specific cutting pressure with an increase of the drill diameter. Conversely, the drilling process for all materials resulted in high roughness values for the inner surface of the holes. The highest roughness for the inner surface was recorded when the glass/epoxy was drilled. Nevertheless, the addition of the date palm fibre also contributed to an increase of surface roughness of the composites. However, there was less of an increase in the roughness of the inner surface with the addition of date palm fibres to the composite compared to glass fibres. Machining power was influenced by the higher operating parameter values; however, for the intermediate and low range operating parameter values, there was not much difference in the machining power of all materials. Interestingly, the machining power for the date/epoxy composite was competitive when compared to the neat epoxy, which is a promising result for the use of date palm fibre from a machinability perspective

Teacher evaluation by different internal evaluators: Head of departments, teachers themselves, peers and students

This study analyzed teacher evaluation in school, through involving different internal evaluators, in order to determine the extent to which they evaluate teacher performance accurately and objectively. Evaluation survey instruments are used in this study, which are designed based the criteria of existing teacher evaluation system in the context, along with other criteria for evaluating teachers. The sample of this study included teachers, heads of departments and students from high schools in four different districts in Kuwait, received responses as 100 from heads of department, 100 from teachers ‘self-evaluation’, 100 from peer and 912 from students. The findings show that there is no significant difference between teachers’ self-evaluation and heads of departments’ evaluation. On the other hand, this study finds that subjectivism and competition may have an effect on peer evaluation and students may over-evaluate their teachers’ performance as attempt to draw a better picture of their teachers in front of evaluators

Teacher Evaluation in Kuwait - Evaluation of the Current System and Consideration of Risk-Based Analysis as a Principle for Further Development

Evaluation is an essential component in education. Through evaluation, educationists can identify what has been achieved, what needs to be improved and what should be developed. Educational evaluation can be applied to several areas, such as curricula, students, teachers and schools in general. This study focuses on teacher evaluation and argues that teacher evaluation systems should be more effective in accurately determining teacher performance, should support the making of fair decisions in relation to sanctions or rewards and should support professional development. The aims of this study were firstly to analyse and evaluate the current teacher evaluation system in Kuwait, and secondly, to suggest an alternative teacher evaluation system based on a ‘Risk-Based Analysis’ approach. This study used a combination of quantitative and qualitative methods to gather data. In particular, a questionnaire was designed to collect teachers’ perspectives on the current system and was distributed to 599 teachers in nine primary schools in three Kuwaiti educational districts. Interviews were conducted with nine head teachers and twelve inspectors in order to obtain more in-depth data regarding the current system. The study also carried out additional interviews with the same head teachers and inspectors, and held a focus group with 45 teachers, in order to probe their views concerning the proposed alternative system. The results of this study have revealed that the actual purposes of the current system are primarily focused on achieving summative evaluation, while the desired purposes of teacher evaluation are to secure both summative and professional development. The current system most frequently uses observation to evaluate teacher performance; however, participants expressed a desire for a broader range of evaluation tools to be used. The study found that teachers more frequently have discussions with, and receive written feedback from, heads of departments as opposed to the other two evaluators (head teachers and inspectors). They rated the value of the discussion and written feedback from heads of departments as more valuable than that which is given by the other two groups of evaluators. The study also found that teachers’ views were clustered, with some teachers indicating that the current system does not support them in their performance development and others indicating that it does. Finally, the study found that adopting the alternative system would improve the validity and reliability of teacher evaluation, would link teachers’ performance with promotions and rewards while introducing sanctions for underperforming teachers, as well as would facilitate and promote professional development

Design of Film Bulk Acoustic Wave Sensor for Internet of Things (IoT) Applications

التوسع السريع لإنترنت الاشياء أدى إلى زيادة الطلب على تقنيات الاستشعار المبتكرة التي يمكن أن توفر بيانات في الوقت الفعلي لمختلف التطبيقات. رنانات الموجات الصوتية ذات الاغشية الرقيقة (FBARs) هي رنانات مصغرة تستخدم التأثير الكهرو إجهادي لإنشاء إشارات كهربائية باستخدام الاهتزازات الميكانيكية والعكس صحيح. ظهرت رنانات FBAR كمتحسسات واعدة لتطبيقات الاستشعار في إنترنت الأشياء نظرًا لحجمها الصغير وحساسيتها العالية وتوافقها مع تقنيات التصنيع الدقيق. يقدم هذا البحث تصميم مستشعر FBAR  لتطبيقات انترنت الاشياء التي تتكون من أكسيد الزنك (ZnO) و ليثيوم نيوباتيت(LiNbO3)  كمواد كهروضغطية والالمنيوم كأقطاب كهربائية علوية وسفلية. تظهر النتائج الأداء المتفوق للرنان المقترح. بناءً على نتائج النمذجة ، فإن تردد الرنين هو 12.02 و 10.36 جيجاهرتز مع عامل جودة 936.7 و 941.3 ومعامل الاقتران الفعال 18.35 و 18.27٪ لـ أكسيد الزنك و ليثيوم نيوباتيت على التوالي.The Internet of Things (IoT) is expanding quickly, which has increased demand for innovative sensing technologies that can provide real-time data for various applications. Film Bulk Acoustic Wave Resonators (FBARs) are miniature resonators that utilize the piezoelectric effect to create electrical signals using mechanical vibrations and vice versa. FBAR resonators have emerged as promising candidates for sensor applications in IoT due to their compact size, high sensitivity, and compatibility with microfabrication techniques. This paper presents design of FBAR sensor as gas and pressure sensor for IOT applications consisting of zinc oxide (ZnO) and Lithium niobate (LiNbO3) as piezoelectric film and Aluminum (Al) as top and bottom electrodes. The results show the superior performance of the proposed resonator. Based on the modeling results, the structure's resonance frequency is 12.02 and 10.36 GHz with a quality factor of 936.7 and 941.3 and an effective coupling coefficient of  18.35 and 18.27 % for ZnO and LiNbO3 respectively

Performance of Teaching and Learning Technology Internship Students as Perceived by Their Trainers

The purpose of this descriptive study is to evaluate the performance of teaching and learning technology students of the College of Education, Sultan Qaboos University during their internship experience. Trainers of the interns rated them on 15 items of performance as displayed in the questionnaire of the study. The internal consistency of the questionnaire was significantly high (.96). It was observed that the general level of performance of the interns was high (a mean of 4.40 out of 5) and the ratings of the individual items of performance ranged from 4.04 to 4.59. However, no gender significant differences were observed in the global ratings of males and females. Apart from this, it was found that 2014 cohort interns performed better than earlier cohorts (before 2014).  The study reveals other significant findings such as location of internship (public or private sector) did not affect performance of interns. Similarly, type of institution (educational or non-educational) was not a significant factor of performance, however, interns in non-educational institutions performed better (though not significantly) than interns in educational institutions). Interns with higher GPAs outperformed their colleagues with lower GPAs. Keywords: Internship evaluation, supervisors’ ratings of interns, teaching and learning technolog

Inclusion of the Domains of Sustainable Development in Al Hadith Text Books in the Intermediate Stage

This study aims to identify the areas of sustainable development that should be included in the textbooks of Prophetic Sayings (Hadeeth) in the Kingdom of Saudi Arabia, to determine the degree of availability, and to find out if there are statistically significant differences at (α≤0.05) in the degree of availability. The descriptive analytical method was used to analyze the whole study population. Cooper coefficient of stability, frequencies, and percentages were used to analyze the results and measure the degree of availability of these fields. Chi Square equation was also used to measure the differences between the availability of fields among grades. The social field was firstly ranked with a percentage of 78.16%, and a total of 433 frequencies, while the environmental field followed it with a percentage of 6.98% and a total of 37 frequencies. The paper showed that there were statistically significant differences in the inclusion in Chi equation