A Device-to-Device direct discovery algorithm to mitigate the collision caused by hidden users

Device-to-Device (D2D) discovery is an essential constituent in D2D communications as a future generation of wireless communication networks. Direct discovery enables users to discover their neighbors to exchange traffic without the cellular-networks assistance in order to enhance spectral efficiency and throughput. Despite its role to reduce signaling load, few works pay sufficient attention to direct discovery. According to the latest density of users detected by User Equipments (UEs) and their neighbors, this study suggests an adaptable, neighborhood-aware D2D direct discovery technique. To distinguish concealed UEs from other UEs, this technique employs a novel classification method. It also uses its neighborhood-aware capability to avoid severe collisions among all users, including hidden users. The performance of the proposed algorithm is compared with the recent adaptive algorithms and the algorithm recommended by the 3GPP standard. We evaluate algorithms in metrics such as discovery delay and the number of beacons required to terminate the discovery process. The simulation results show that the number of beacons, collision, and discovery delay considerably decrease via the proposed algorithm.     

化学教学论课程实施中化学师范生教育教学能力的形成机理*

基于《中学教育专业师范生教师职业能力标准》提炼了师范生教育教学能力体系,体系涵盖了师德践行能力、实践教学能力、综合育人能力和专业发展能力等4项能力及对应的10方面能力要素。以化学教学论课程为例,分析了其章节内容与4项能力的对应关系,探讨了课程实施中化学师范生教育教学能力形成的机理和途径。化学师范生4项能力的形成机理各有特点,需要师范生和教师积极互动。     

Operational research and ethics: A literature review

Any human activity raises ethical questions, questions about ‘good’ and ‘right’ ways to act and to live; or to put it differently, questions of values and responsibility. From its inception operational research (OR) has engaged with such questions in terms of professional behavior, the handling of preferences in OR, the societal role of OR, the process of OR intervention and the content of OR analysis. As a result, analytical methods and processes have been developed to help clients explore the ethical dimension of their decisions. The paper reviews the literature published in selected OR journals (Management Science; Operations Research; Interfaces; the European Journal of Operational Research; the Journal of the Operations Research Society; Omega; International Transactions in Operational Research; the Journal of Multi-Criteria Decision Analysis), organizing it along the lines of OR’s core competences. The review identifies a number of significant research programmes that are well established and are being energetically pursued; the research findings are being applied to a wide range of important issues. Ethical questions lie at the heart of the great governmental and commercial issues of the day: economic growth and instability; inequality and injustice; environmental degradation and sustainability. They also lie at the heart of the more mundane decisions of day-to-day OR. ‘Ethics’ therefore provides a useful focus for OR both in terms of raising the awareness of all concerned and in providing a theme for research. As a result of the review some research questions are suggested. There is much of interest, much to do.     

The Performance of the Time-Frequency Analysis Software (TF32) in the Acoustic Analysis of the Synthesized Pathological Voice

The purpose of this study was to examine the algorithm-measuring capabilities used in the Time-Frequency Analysis Software Program for 32-bit Windows (TF32) for measuring fundamental frequency (F0), its dependent measures, and signal-to-noise ratio (SNR). The stability, accuracy, and linearity of its algorithm to systematic changes in aspiration noise and/or spectral slope (to mimic the perceptual characteristics of breathiness, roughness, and hoarseness) were evaluated using its analysis output to five female and five male synthesized voices. TF32 was used to calculate F0, Jitter%, Shimmer%, and SNR for each of the synthesized signals. The findings indicate that although TF32 produced stable results for male synthesized samples, they were not accurate when measuring F0, Jitter%, and Shimmer% with the addition of noise and variations in open quotient independently and in combination. In contrast, TF32 was neither stable nor accurate in making the same measurements for female synthesized samples. However, TF32 was stable and accurate in measuring SNR for male and most of female voices. These results point to an inappropriate F0 extraction algorithm in TF32 and stress the need for further research to remediate the algorithm or to identify a superior one.     

A heuristic for the multi-satellite,multi-orbit and multi-user management of Earth observation satellites

Earth observation satellites are platforms equipped with optical instruments that orbit the Earth in order to take photographs of specific areas at the request of users. This article is concerned with the management of several satellites performing multiple orbits over a given planning horizon. It describes a tabu search heuristic for the problem of selecting and scheduling the requests to be satisfied, under operational constraints. An upper bounding procedure based on column generation is used to evaluate the quality of the solutions. The results of extensive computational experiments performed on data provided by the French Centre National d’Études Spatiales are reported.