A novel OFDM transmission scheme with length-adaptive Cyclic Prefix

INTRODUCTION In broadband wireless communication, thdelay spread caused by channel multi-path fadinwill usually introduce serious Inter-Symbol Interference (ISI) to the receiver. To counteract the ISIthe high-efficiency Orthogonal Frequency DivisioMultiplexing (OFDM) modulation first splits thhigh-rate data stream into a number of parallesub-streams and modulates them onto differenorthogonal sub-carriers and thus lower the symborate, and then add a Cyclic Prefix (CP) to the h…     

In defence of speech codes

It has been strongly maintained that speech codes at universities interfere with academic freedom, and also, to the contrary, that such speech codes must be developed to restrain appeals to academic freedom that function to restrain the freedom of marginalized groups to participate fully in the university. This essay argues that forms of speech can in fact constrain the freedom, including legitimate academic freedom, of many persons, not only, but importantly including, marginalized groups; that speech codes have always existed; and that reasonable ones can be developed which do not interfere with freedom of teaching, learning, and research in the university; and in particular that definitions of academic freedom such as that developed by the Canadian Association of University Teachers (CAUT) are compatible with such speech codes.     

ACADEMIC DISHONESTY: A Zero Tolerance Professor and Student Registration Choices

College and university faculty and administrators are responsible for constructing academic honesty policies and communicating them to students. This is often attempted through institutional honesty policies and university-wide honor codes. While these approaches have been widely researched, less attention has been given to the role of individual faculty members. That role is examined in this study by addressing student reactions to professors based on their academic honesty policies. In addition to demographic information, data were gathered about student attitudes and beliefs concerning academic dishonesty and their decision to enroll in or avoid a course being taught by a professor with zero tolerance for academic dishonesty. The findings regarding different instructors’ approaches toward academic dishonesty indicate that an intolerant policy will keep dishonest students away, but at a price—it will also detract many honest students.     

Codes over Galois rings with respect to the Rosenbloom-Tsfasman metric

We investigate the structure of codes over Galois rings with respect to the Rosenbloom-Tsfasman (shortly RT) metric. We define a standard form generator matrix and show how we can determine the minimum distance of a code by taking advantage of its standard form. We compute the RT-weights of a linear code given with a generator matrix in standard form. We define maximum distance rank (shortly MDR) codes with respect to this metric and give the weights of the codewords of an MDR code. Finally, we give a decoding technique for codes over Galois rings with respect to the RT metric.     

Engineering problem-solving knowledge: the impact of context

Employer complaints of engineering graduate inability to ‘apply knowledge’ suggests a need to interrogate the complex theory-practice relationship in twenty-first century real world contexts. Focussing specifically on the application of mathematics, physics and logic-based disciplinary knowledge, the research examines engineering problem-solving processes as enacted by recent graduates in a range of industrial settings. Theoretically situated in the sociology of education, the Bernsteinian concept of knowledge structures and Legitimation Code Theory epistemic relations are utilised to surface the disciplinary basis of problem solving in different sociotechnical contexts. It is argued that the relationship between the ‘what’ and the ‘how’ of the problem gives rise to significantly different practice ‘codes’ between which successful engineering problem-solvers are required to shift. This paper presents two contrasting case studies which demonstrate the impact of the environment on code-shifting practices. Findings suggest that engineering curricula need to facilitate a more conceptual grasp of contextual complexities.     

Skeleton Trees for the Efficient Decoding of Huffman Encoded Texts

A new data structure is investigated, which allows fast decoding of texts encoded by canonical Huffman codes. The storage requirements are much lower than for conventional Huffman trees, O(log² n) for trees of depth O(log n), and decoding is faster, because a part of the bit-comparisons necessary for the decoding may be saved. Empirical results on large real-life distributions show a reduction of up to 50% and more in the number of bit operations. The basic idea is then generalized, yielding further savings.     

中国火电企业碳排放测算及预测分析

如何预测和分析火力发电企业的碳排放成为低碳经济研究领域中十分重要的问题。本文分析了我国火电企业的发展现状,并与世界主要发达国家进行了对比研究;根据政府间气候变化专门委员会（IPCC）2006年版碳排放计算指南和不同能源品种的碳排放系数,计算出了1997年-2009年中国火力发电企业碳排放;运用含误差修正的改进的GM（1,1）模型对中国火力发电企业的碳排放进行预测分析,并根据碳排放现状和预测结果总结了我国火电企业碳排放特征。分析结果表明：在保持过去发展规律不变的情况下,中国火力发电企业碳排放量成增长的趋势,并且火电企业的碳排放趋势可以划分为5个阶段。总之,必须通过技术进步来提高能源利用效率和降低单位能耗,使中国火力发电企业实现低碳经济发展。     

基于变长Turbo码的低复杂度联合信源信道译码

基于变长Turbo码的联合信源信道译码通过构造联合译码平面网格图,具有比比特级译码更好的性能.但平面网格图复杂,使变长Turbo码译码复杂度高.基于此,构造了一个空间网格图,提出基于变长Turbo码的低复杂度联合信源信道译码方法.仿真结果表明,该算法比平面网格图计算复杂度减少约3.8%,在SER(symbol error ratio)为10^-4时,获得E_b/N₀增益约为0.2dB.     

Scan and Learn: Quick Response Code Enabled Museum for Mobile Learning of Anatomy and Pathology

In the past, medical museums played a significant role in anatomy and pathology training. The attraction of medical museums has declined recently due to the emergence of information technology and innovative medical curricula. An innovative mobile learning platform has been developed using quick response (QR) codes for the museum specimens at the Lee Kong Chain School of Medicine, Singapore. High-quality images of the potted specimens were captured and combined into an album and a video using Adobe Acrobat Pro 9 and Windows Movie Maker, respectively. Subsequently, QR codes were generated linking to PDF documents with annotations, pathology, and clinical history concerning the specimens. Quick response codes were piloted in gastrointestinal teaching module for Year 2 medical students. Survey responses were obtained from students to verify the efficacy of QR as a learning tool. The majority of students either agreed or strongly agreed that it was easy to access the information about the specimen with QR codes (4.47 ± 0.84), while 96% of students agreed that they are able to correlate the specimen with the annotated images (4.56 ± 0.56). The majority of students (78%) agreed that QR codes are useful for their learning (4.22 ± 0.87), while 75% of students felt QR codes motivate them to visit Anatomy Resource Centre. Most of the students agreed that QR codes are useful for revision of materials (4.13 ± 1.07) and independent learning (4.38 ± 0.87). These findings suggest that QR codes are not only effective for students learning but also enhance their exploration experience with the museum specimens.     

本溪资源型产业如何实现"华丽的转身"

本溪作为典型资源型城市的老工业基地,以循环经济为视角,优化产业结构,加快产业升级,是本溪市资源型产业面临的最为迫切的任务。本文通过梳理本溪资源型产业转型的资源枯竭与环境问题、经济问题、三次产业问题,依托本溪市优越的区位条件、丰富的自然资源、不断完善的基础建设等,阐述了本溪市资源型产业转型的路径。