• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5898-5916
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• 2018

In this paper, the downlink performance of multi-cell distributed antenna systems (DAS) with a single user in each cell is investigated. Assuming the channel state information is available at the transmitter, four transmission modes are formulated as combinations of remote antenna units (RAUs) selection and cooperative transmission, namely, non-cooperative transmission without RAU selection (NCT), cooperative transmission without RAU selection (CT), non-cooperative transmission with RAU selection (NCT_RAUS), and cooperative transmission with RAU selection (CT_RAUS). By using probability theory, the cumulative distribution function (CDF) of a user's signal to interference plus noise ratio (SINR) and the system ergodic capacity under the above four modes are determined, and their closed-form expressions are obtained. Furthermore, the system energy efficiency (EE) is studied by introducing a realistic power consumption model of DAS. An expression for determining EE is formulated, and the closed-form tradeoff relationship between spectral efficiency (SE) and EE is derived as well. Simulation results demonstrate their consistency with the theoretical analysis and reveal the factors constraining system EE, which provide a scientific basis for future design and optimization of DAS.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.1
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• pp.258-272
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• 2022

The technology implementation method was diversified into an 'autonomous cooperative driving' method to overcome the limitations of a stand-alone autonomous vehicle with vehicle sensor-based autonomous driving. The autonomous cooperative driving method involves exchanging information between roadside infrastructure and autonomous vehicles. In this process, the concept of dynamic information (LDM), a target of cooperation, was established. But, evaluation methods and standards for dynamic information have not been established. Therefore, this study, a dynamic information evaluation method based on information on pedestrians within the moving objects. In addition, autonomous cooperative driving was demonstrated, and dynamic information was also verified through the evaluation method. The significance of this study is that it established the dynamic information evaluation methodology for autonomous cooperative driving for the first time. Based on this, this study is expected to contribute to the application of safe autonomous cooperative driving technology to the field.

• Proceedings of the Technology Innovation Conference
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• 1996.12a
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• pp.141-153
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• 1996

Firms prefer in some specific conditions cooperative R&D to non-cooperative for developing technology. Previous studies on the conditions show firms want to choose cost-sharing type of cooperative R&D (the CS-RJV) rather than non-cooperative one when target technology is either 'relatively easy'or 'relatively difficult', and to join multiple-research type of cooperation (the MR-RJV) than to compete each other if technology is only 'relatively easy'. However, by introducing technological spillover as well as difficult of technology, only if there shown that this seemingly contrasted phenomenon almost disappears : the MR-RJV can i3e also preferred by firms even in case of 'relatively difficult'technology only if there exists some extent of a technological spillover.

• Journal for History of Mathematics
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• v.33 no.3
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• pp.167-177
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• 2020

Cooperative behavior may seem contrary to the notion of natural selection and adaptation, but is widely observed in nature, from the genetic level to the organism. The origin and persistence of cooperative behavior has long been a mystery to scientists studying evolution and ecology. One of the important research topics in the field of evolutionary ecology and behavioral ecology is to find out why cooperation is maintained over time. In this paper we take a historical overview of mathematical models representing cooperative relationships from the perspective of mathematical biology, which studies population dynamics between interacting biological groups, and analyze the mathematical characteristics and meanings of these cooperative models.

• The Mathematical Education
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• v.43 no.1
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• pp.51-74
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• 2004

During cooperative learning in small group, we investigate what characteristics children in elementary school show at several fields of mathematics and through communicating activity etc., what influence the cooperative learning does on children's attitude, thinking, problem solving, recognition. To know them, we observe the process of children's communication and evaluate children's attitude, thinking, problem solving, recognition with checklist at each lesson. Through this research, we conclude that the figure part is the most effective when we teach with cooperative learning type, and the cooperative learning evoke the vivid communication, and make progress in affirmative attitude, thinking etc. Also, in this thesis we suggest the points which teacher should consider when he/she use cooperative learning in small-group.

• English Language & Literature Teaching
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• v.10 no.1
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• pp.127-152
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• 2004

The purpose of this study is to elaborate design strategies for a Web-based self-directed cooperative distance language learning community. Research was done regarding the theoretical foundations for self-directed cooperative language learning and Web-based learning communities. The components of a Web-based community for self-directed cooperative language learning system are also investigated. As a result of this study, design strategies for Web-based communities are suggested. There are performance and supporting environments(synchronous/asynchronous) for self- directed cooperative language learning. There are also cultural experiences and communication factors in the performance field. Furthermore, matching communicators, finding and offering information, language learning content and other supporting agents are important in the supporting environment.

• ETRI Journal
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• v.46 no.2
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• pp.175-183
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• 2024

Recently, polar code has attracted the attention of many scholars and has been developed as a code technology in coded-cooperative communication. We propose a polar code scheme based on Plotkin structure and quasi-uniform punching (PC-QUP). Then we apply the PC-QUP to coded-cooperative scenario and built to a new coded-cooperative scheme, which is called PCC-QUP scheme. The coded-cooperative scheme based on polar code is studied on the aspects of codeword construction and performance optimization. Further, we apply the proposed schemes to space-time block coding (STBC) to explore the performance of the scheme. Monte Carlo simulation results show that the proposed cooperative PCC-QUP-STBC scheme can obtain a lower bit error ratio (BER) than its corresponding noncooperative scheme.

• The Journal of Fisheries Business Administration
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• v.36 no.3 s.69
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• pp.37-63
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• 2005

According to the Fisheries Cooperative Law, the Fisheries Cooperative has made a substantial contribution to the development of Korea's fisheries industry amid the nation's rapid economic growth and drastic social changes since its establishment in April 1st 1962, It is, however, generally believed that the cooperative has made a poor performance in improving its business constitution. Therefore, the reform of its board of director system is one of the ways to strengthen the constitution. For the purpose of making the board of director system to operate rationally, this dissertation is divided into five chapters. Chapter I provides an overview of this study, such as research background and objectives. Chapter II focuses on the Fisheries Cooperative's board of director: its function, composition, and election. Chapter III analyzes the responses of the Fisheries cooperatives to questionnaires about the board of director system, and subsequently presents the causes and the meaning of the analysis results. Chapter IV deals with the various ways to improve the Fisheries Cooperative's board of director system, including director and cooperative governance. Finally, Chapter V draws a conclusion of this study. The independent function of the Cooperative's board of director and responsible directorship is one of the most important factors which can prevent the Cooperative from insolvency. Unlike the past, not only it has become difficult to keep the Cooperative's business under the government's support, but also the Cooperative itself is now facing a situation where the support from the government cannot be expected. This ist he reason why the Cooperative should manage itself autonomously, workout its organization, and respond to the current situation with a renovativemanagement and business strategy. Therefore, a rational operation of the board of director is urgently needed.

• Land and Housing Review
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• v.10 no.4
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• pp.31-39
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• 2019

Singapore, a city state with less than 6 million population, has continued successful cooperative development and become one of the most successful Asian countries in exporting expertise in urban and real estate development. This research aims to analyze Singapore's cooperative development with socialist countries including China and Vietnam from Singapore's perspective as an investor. For cooperative development projects in China, Singapore adopted Singapore-style physical urban planning concepts as well as its own institutional and administrative systems. Singapore-Vietnam cooperative development managed to acquire profitable land and diversify its portfolio in terms of industry types and rents. This made Singapore's industrial parks more competitive than other parks in Vietnam. By showcasing successful project implementation in China and Vietnam, Singapore has proved that its model for industrial park and urban development is transferable. Singapore's success in cooperative development with socialist countries provides important implications for future cooperative development between South and North Korea. For example, phased development approaches starting from individual industrial parks expanding to mixed-use townships will be very useful to realize sustainable urban planning in North Korea and reduce financial risks. Singapore dominated development opportunities in advance when socialist countries opened their economy. To pattern ourselves after Singapore, we should not only improve our relationship with North Korea but also prepare with practical components such as financing and organizational structure.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.9
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• pp.113-119
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• 2021

With the increasing pressure of international competition, urban agglomeration cooperation and innovation had become an important means of regional economic development. This study analyzed the spatial characteristics of the Urban Cooperative Innovation Network in Guangdong-Hong Kong-Macao Greater Bay Area, found out the dynamic evolution law of innovation, provided suggestions for policy management departments, and effectively planned the industrial layout. According to the data of the State Intellectual Property Office of China, this study researched invention patents from 2005 to 2019. This paper constructed the urban cooperative innovation network, and took 11 cities in the bay area as the research objects, and used social network analysis to study the spatial structure and dynamic evolution of the urban innovation network. Every indicator reflected the urban cooperative innovation, but they all showed a certain decline in 2008-2010. And it is inferred that the innovation network space of each city will be "obvious fist advantages, significant spillover effect and weakening role of Hong Kong and Macao". This paper divided urban cooperative innovation of Guangdong-Hong Kong-Macao Greater Bay Area into three stages. Summing up the characteristics of each stage is helpful to recognize the changes of urban cooperative innovation and to do a good job in industrial layout planning.