491 research outputs found

    Tilings of the Sphere by Edge Congruent Pentagons

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    We study edge-to-edge tilings of the sphere by edge congruent pentagons, under the assumption that there are tiles with all vertices having degree 3. We develop the technique of neighborhood tilings and apply the technique to completely classify edge congruent earth map tilings.Comment: 36 pages, 34 figure

    Rational Angles and Tilings of the Sphere by Congruent Quadrilaterals

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    We apply Diophantine analysis to classify edge-to-edge tilings of the sphere by congruent almost equilateral quadrilaterals (i.e., edge combination a3b). Parallel to a complete classification by Cheung, Luk and Yan, the method implemented here is more systematic and applicable to other related tiling problems. We also provide detailed geometric data for the tilings.Comment: 79 pages, 41 figures, 16 tables, 2 algorithms. Spherical Geometr

    How science, technology, engineering, mathematics (STEM) project-based learning improves student learning

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    The purpose of this paper is to examine how extra-curricular and academic performance is affected by student participation in Science, Technology, Engineering and Mathematics (STEM) under project-based learning (PBL) activities. General observation and quantitative analysis was used to evaluate the two aspects. A solar car team project under the philosophy of STEM and PBL is developed and more than two hundred students from electrical and mechanical engineering field participated in the team project and learnt the STEM PBL core value. The team aims to develop a solar-powered vehicle to demonstrate the viability of a renewable energy through the use of green transportation, to promote the awareness of environmental sustainability among the public. It also provides students with an opportunity to put theoretical knowledge into practice, gain hands-on experience, and practice project management skills during development, and thus leading student to understanding science and new technology; and practising engineering skills and mathematics. Till now, six solar vehicles were built with the massive efforts of students. Moreover, design thinking process is adopted to engage and motivate students to learn and develop in the team. The entire process includes the following steps: ā€˜Empathizeā€™, allowing students to learn about their audience for their designing process; ā€˜Defineā€™, constructing a point of view that is based on user needs and insights; ā€˜Ideateā€™, brainstorming and coming up with creative solutions; ā€˜Prototypeā€™, building a rePresentation of one or more of student ideas to show to others and ā€˜testā€™, returning to original user group and testing their ideas for feedback. The team students showed significantly growth rates on research, planning, project implementation and reporting. The team also assists studentsā€™ further STEM studies and STEM career planning, and the nurturing of diversified talents with a range of capabilities at different levels in STEM knowledge development. In addition, the team organizes solar car workshops and demonstrations, and supervises group projects for secondary school students. Result of the study implied that STEM with PBL in school benefitted students in that they achieved a greater extension on extra-curricular and academic aspect, especially gaining more solid knowledge in technology and engineering

    Managing inter-agency co-ordination : an analysis of district level administration in Hong Kong

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    published_or_final_versionPolitics and Public AdministrationMasterMaster of Public Administratio

    Reliable and valid NEWS for Chinese seniors: measuring perceived neighborhood attributes related to walking

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    Background : The effects of the built environment on walking in seniors have not been studied in an Asian context. To examine these effects, valid and reliable measures are needed. The aim of this study was to develop and validate a questionnaire of perceived neighborhood characteristics related to walking appropriate for Chinese seniors (Neighborhood Environment Walkability Scale for Chinese Seniors, NEWS-CS). It was based on the Neighborhood Environment Walkability Scale - Abbreviated (NEWS-A), a validated measure of perceived built environment developed in the USA for adults. A secondary study aim was to establish the generalizability of the NEWS-A to an Asian high-density urban context and a different age group. Methods : A multidisciplinary panel of experts adapted the original NEWS-A to reflect the built environment of Hong Kong and needs of seniors. The translated instrument was pre-tested on a sample of 50 Chinese-speaking senior residents (65+ years). The final version of the NEWS-CS was interviewer-administered to 484 seniors residing in four selected Hong Kong districts varying in walkability and socio-economic status. Ninety-two participants completed the questionnaire on two separate occasions, 2-3 weeks apart. Test-rest reliability indices were estimated for each item and subscale of the NEWS-CS. Confirmatory factor analysis was used to develop the measurement model of the NEWS-CS and cross-validate that of the NEWS-A. Results : The final version of the NEWS-CS consisted of 14 subscales and four single items (76 items). Test-retest reliability was moderate to good (ICC > 50 or % agreement > 60) except for four items measuring distance to destinations. The originally-proposed measurement models of the NEWS-A and NEWS-CS required 2-3 theoretically-justifiable modifications to fit the data well. Conclusions : The NEWS-CS possesses sufficient levels of reliability and factorial validity to be used for measuring perceived neighborhood environment in Chinese seniors. Further work is needed to assess its construct validity and generalizability to other Asian locations. In general, the measurement model of the original NEWS-A was generalizable to this study context, supporting the feasibility of cross-country and age-group comparisons of the effect of the neighborhood environment on walking using the NEWS-A as a tool to measure the perceived built environment

    Looking back to look forward: Setting future research agenda for international business in textiles and clothing industry

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    Ā© 2019 Jungseok Research Institute of International Logistics and Trade All rights reserved. Since its development by Tinbergen (1962), the gravity model of international trade has widely been applied to analyse the effect of various factors on trade relationships between countries. Past studies on trade gravity vary not only in the mix of model variables but also in how they have come into the analysis. This study reviews existing literature on bilateral trade with an aim to identify influential predictors such as changes of trade policy and national development strategy and highlight important yet understudied factors such as transport and logistics infrastructure, and sustainable development. To demonstrate the needs to examine these critical factors across industry sectors, the study presents the case of textiles and clothing (T&C) production and trade between China and its trading partners as an illustration. Through the literature review, it shows how the gravity model can be applied to address current issues in international trade arena such as the potential trade war between the US and China, China\u27s Belt and Road Initiative (BRI), and other important factors shaping global T&C trade. This study offers future research directions for analysis of global trade in the T&C industry and contributes to the wider literature of international business and trade

    The Belt and Road Initiative\u27s impact on Textile and Clothing Supply Chains in Asia: Views from Hong Kong Industrial Stakeholders

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    The global supply chains in the Textile and Clothing (T&C) industry have been shaping by various forces, among them economic development policy is one of the strongest. Amid the rollout of the Chineseā€™s new national development strategyā€”Belt and Road Initiative (BRI), major T&C companies see both opportunities and challenges in optimizing and restructuring the networks of their production facilities. One notable and growing trend associated with the BRI is the relocation of T&C manufacturing from China to ASEAN countries and establishment of new factories along the Belt and Road (B&R). Much has been examined about the BRI at the national level, yet little is known about how companies in the T&C industry have responded to this grand economic development plan. This study aims to explore from industrial stakeholdersā€™ perspectives, the factors that drive and hinder synergistic, mutually beneficial development of T&C production and trade among the B&R countries. To achieve this aim, it addresses the following questions: what are the challenges and opportunities faced by T&C companies establishing or relocating production to B&R countries, and what tangible actions have been taken by them? In-depth interviews were carried out with ten industry professionals from Hong Kong-based companies and government institutions involved with T&C trade in the Asian B&R countries, such as Bangladesh, Cambodia, Indonesia and Myanmar. The findings of this study highlight the importance of pursuing sustainable development. On one hand, there is full of potential for T&C companies to achieve cost-effective production along the B&R countries through harnessing economic policy and transport infrastructure that facilitate trade. On the other hand, T&C companies see challenges in managing culturally diversity in the workplace as opportunities for pursuing corporate development in a socially responsible manner. In sum, this study reveals mutual supportiveness of economic and social aspects of T&C production and trade

    Multiple Block-Size Search Algorithm for Fast Block Motion Estimation

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    Abstract-Although variable block-size motion estimation provides significant video quality and coding efficiency improvement, it requires much higher computational complexity compared with fixed block size motion estimation. The reason is that the current motion estimation algorithms are mainly designed for fixed block size. Current variable block-size motion estimation implementation simply applies these existing motion estimation algorithms independently for different block sizes to find the best block size and the corresponding motion vector. Substantial computation is wasted because distortion data reuse among motion searches of different block sizes is not considered. In this paper, a motion estimation algorithm intrinsically designed for variable block-size video coding is presented. The proposed multiple block-size search (MBSS) algorithm unifies the motion searches for different block sizes into a single searching process instead of independently performing the search for each block size. In this unified search, the suboptimal motion vectors for different block sizes are used to determine the next search steps. Its prediction quality is comparable with that obtained by performing motion search for different block sizes independently while the computational load is substantially reduced. Experimental results show that the prediction quality of MBSS is similar to full search. Block matching, motion estimation, video coding, search pattern, directional search
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