• 대한전기학회논문지:전력기술부문A
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• 제55권6호
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• pp.259-264
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• 2006

This paper addresses the collusive bidding that functions as a potential obstacle to a fully competitive wholesale electricity market. Cooperative game is formulated and the equation of its Nash Equilibrium (NE) is derived on the basis of the supply function model. Gencos' willingness to selectively collude is expressed through a bargain theory. A Collusion Incentive Index(CII) for representing the willingness is defined through computing the Gencos' profits at NE. In order to keep the market non-cooperative, the market operator has to know the highest potentially collusive combination among the Gencos. Another index, which will be called the Collusion Monitoring Index(CMI), is suggested to detect the highest potential collusion and it is calculated using the marginal cost functions of the Gencos without any computation of NE. The effectiveness of CMI for detecting the highest potential collusion is verified through application on many test market cases.

• 영어어문교육
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• 제17권4호
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• pp.75-95
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• 2011

The purpose of this study was to evaluate a group activity, reciprocal peer tutoring (RPT), in order to investigate advantages and challenges of RPT in promoting cooperative and collaborative learning environment for EFL University reading instruction. The participants in this study were 89 students taking an English reading course at a Korean university. RPT is a learning strategy whereby learners help each other and learn by teaching. This program was supported by a Vygotskyan perspective which assumes that learners gain mastery and develop cognitive skills through social interaction with more proficient others and their environment. This study relied particularly on participant perceptions through questionnaire survey and Anonymous Online class Report of the course. This study showed various advantages for tutors such as learning through teaching and becoming more autonomous and responsible for their own learning. Non-threatening and highly motivating learning atmosphere are parts of benefits for tutees. Other advantages for tutees included improved level of academic self-confidence, and motivation. This study also revealed several drawbacks associated with the problem of inaccuracy in students' production and students' demand for more direct teacher role. (182 words).

• Journal of Communications and Networks
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• 제13권3호
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• pp.257-265
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• 2011

In this paper, a cooperative relaying protocol called soft-decision-and-forward (SDF) with multiple antennas in each node is introduced. SDF protocol exploits the soft decision source symbol values from the received signal at the relay node. For orthogonal transmission (OT), orthogonal codes including Alamouti code are used and for non-orthogonal transmission (NT), distributed space-time codes are designed by using a quasi-orthogonal space-time block code. The optimal maximum likelihood (ML) decoders for the proposed protocol with low decoding complexity are proposed. For OT, the ML decoders are derived as symbolwise decoders while for NT, the ML decoders are derived as pairwise decoders. It can be seen through simulations that SDF protocol outperforms AF protocol for both OT and NT.

• Journal of electromagnetic engineering and science
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• 제12권2호
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• pp.148-154
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• 2012

In this paper, we propose an algorithm to conserve resources of the common control channel in a cognitive radio network by rejecting the redundant users using cooperative spectrum sensing. The proposed scheme is investigated under the paradigm of active spectrum sensing and a sequential detection technique. The algorithm is based on the J-divergence between the hypotheses of non primary user operation and the otherwise case. We select the most significant eigenvalues, which primarily affect the global statistical test. For the case where interference is from a secondary system transmission, a match filter is first employed to remove the degradation, and then the proposed algorithm is employed to remove the cooperative sensing nodes. Numerical results are provided and compared with conventional cases in order to validate the performance of the proposed algorithm.

• ETRI Journal
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• 제42권6호
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• pp.846-858
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• 2020

The non-orthogonal multiple access (NOMA) technique offers throughput improvement to meet the demands of the future generation of wireless communication networks. The objective of this work is to further improve the throughput by including an underlay cognitive radio network with an existing multi-carrier NOMA network, using cooperative communication. The throughput is maximized by optimal resource allocation, namely, power allocation, subcarrier assignment, relay selection, user pairing, and subcarrier pairing. Optimal power allocation to the primary and secondary users is accomplished in a way that target rate constraints of the primary users are not affected. The throughput maximization is a combinatorial optimization problem, and the computational complexity increases as the number of users and/or subcarriers in the network increases. To this end, to reduce the computational complexity, a dynamic network resource allocation algorithm is proposed for combinatorial optimization. The simulation results show that the proposed network improves the throughput.

• 마케팅과학연구
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• 제19권3호
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• pp.28-36
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• 2009

现有的文献广泛的关注财阀以及他们的所有权和支配权的优点和弱点, 但是几乎没有关于韩国非财阀公司的研究. 然而, Lee, Lee and Pennings (2001)并没有特别的探讨在韩国国内市场非财阀公司为求生存而对抗财阀公司的具有竞争力的战略. 本文的研究动机是通过四个探索性案例的研究, 韩国非财阀公司对抗财阀公司的成功的竞争战略和提出的建议可能会对其他的企业以及公共政策制定者有所帮助. 从产品相似性和公司内的合作关系分别定义竞争和合作的概念. 从这两个方面, 我们开发了以下$2{\times}2$ 矩阵, 为非财阀公司对抗财阀公司提供四种竞争战略. 在小组1的非财阀公司在高端市场对财阀公司让步, 但在低端市场有 "我也是在低端市场" 的产品, 同时承认在高端市场的财阀. 在小组2, 非财阀公司以供应商或互补企业的身份成为财阀公司的合伙人. 在小组3, 非财阀企业从事与财阀直接竞争. 在小组4, 非财阀企业的目标, 以产品创新或服务填补目标市场空白点. 我们选择的4个公司分别是E‐Rae电子企业公司(共存方), Intops(供应商), Pantech(竞争对手)和Humax(小众市场成员). 通过分析这4个案例, 相互提供更丰富的洞察力战略. 基于我们的概念框架, 提出下列假设 : 假设1 : 与财阀公司有合作关系的非财阀公司比没有合作关系的公司表现得更好. 假设1a: 共存方会比竞争方表现得更好. 假设1b: 合伙方会比小众市场成员表现得更好. 假设2: 与财阀公司的产品没有相似性的公司比有相似性的公司表现得要更好. 假设2a: 合伙方比共存放表现得更好 假设2b: 小众市场成员会比竞争方表现得更好. 假设3: 小众市场成员应比共存方表现得更好. 假设4: 按绩效的降序排列依次是合作者, 小众市场成员, 共存方, 竞争方. 一组专家按照我们4组的分类把216家非财阀公司分类. 用SPSS统计软件中的简单方差分析来检验假设. 结果发现. 与财阀公司有合作关系的以及提供与财阀公司不同的产品或服务比较好. 很明确的一点是, 平均来说, 若要对抗财阀公司中获利, 其战略是成为合伙人(供应商或组成部分). 直接与财阀公司硬碰硬的竞争是要付出极高代价的战略, 而这种代价不是非财阀公司能负担得起的. 避免与财阀公司迎面竞争的战略是用不同的产品服务于利己市场, 或是服务于被财阀公司忽视掉的低端市场. 些战略是比较好的生存战略. 本文说明在财阀环境中, 韩国的中小型非财阀公司有一些方法可以生存, 尽管不是没有风险. 根据不同的竞争组合, 合作的公司可以根据产品相似性以及合作关系的维度来选择定位从而制定自己的竞争战略. 例如共存方, 竞争对手, 合伙人, 小众市场成员. 根据我们的探索性案例分析, 合伙人对非财阀公司来说可能是最好的战略, 而竞争者则是有很大风险的. 小众市场成员和共存方处于中间, 但前者比后者要好. 很多中小型企业的管理者只是用简单的, 不是合作就是竞争的观点来审视市场的领导者‐典型的就是财阀. 结果. 很多非财阀公司变成被动的合作者或被自己的竞争对手财阀所击败. 事实上, 合作和竞争并不是互相排斥的, 是可以同时被追求的. 正如本文所建议的, 非财阀公司可以根据他们的环境, 内部资源和能力灵活的选择合作和竞争.

• 한국중재학회지:중재연구
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• 제27권1호
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• pp.161-182
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• 2017

The purpose of this study is to investigate the factors of conflict formation, conflict resolution type, and relationship performance between convenience store franchise headquarters and franchise stores operated by the franchise system located in the metropolitan area. The conclusion could be summarized as follows. First, according to factor analysis based on the previous research, the factor of conflict between convenience store headquarters and franchisee was tied to three factors such as goal disagreement, doctrinal discrepancy, and interdependence, whereas conflict resolution type was linked to three factors such as cooperation type, attack type, and avoidance type. Finally, the relationship performance is tied to three factors: financial performance, long-term cooperation, and non-financial performance. Second, as a result of Hypothesis 1, the interdependence was positively correlated when the cooperative type was the dependent variable. The target discrepancy was significantly positive(+) when the aggressive type was the dependent variable. The interdependence was significantly negative(-) when the avoidance type was the dependent variable. There also was a significantly positive(+) relationship in the target disagreement. Third, for Hypothesis 2, it is shown that target inconsistency is negative(-) for all cases where financial performance, long-term cooperation, and non-financial performance are dependent variables. Fourth, for Hypothesis 3, when the financial performance is the dependent variable, only the cooperative type shows a positive(+) relationship. On the other hand, when the long-term cooperation and the non-financial aptitude are the dependent variables, the cooperative type has a significant positive(+) relationship.

• 한국의류학회지
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• 제32권11호
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• pp.1760-1770
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• 2008

The purpose of this study was 1) to find effects of private Guanxi and organizational relationship on quality of organizational relationship, 2) to find effects of private Guanxi and organizational relationship on performance of distribution channel, and 3) to also find effects of quality of organizational relationship on performance of distribution channel. Apparel manufacturers and distributors in China participated in the study. Random sampling method was used to collect the data. Data from 173 questionnaires were used for the statistical analysis. Factor analysis, Cronbach's alpha coefficient, and regression analysis was conducted. Two factors of private Guanxi were classified(i.e., affective Guanxi, instrumental Guanxi). Three factors of organizational relationship type were identified(i.e., opportunistic relationship, cooperative relationship, vertical relationship). The result indicated that affective Guanxi in terms of private Guanxi positively affected on quality of organizational relationship. Cooperative relationship and vertical relationship in terms of organizational relationship positively affected on quality of organizational relationship. Affective Guanxi positively affected on non-financial performance and financial performance in terms of performance of distribution channel. Instrumental Guanxi in terms of private Guanxi positively affected on financial performance only. Cooperative relationship in terms of organizational relationship positively affected on non-financial performance and vertical relationship positively affected on financial performance. Quality of organizational relationship positively affected on non-financial performance and vertical relationship positively affected on financial performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권9호
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• pp.4357-4378
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• 2017

In cooperative multi-relay networks, the relay nodes which are selected are very important to the system performance. How to choose the best cooperative relay nodes is an optimization problem. In this paper, multi-relay selection schemes which consider either single objective or multi-objective are proposed based on evolutionary algorithms. Firstly, the single objective optimization problems of multi-relay selection considering signal to noise ratio (SNR) or power efficiency maximization are solved based on the quantum bee colony optimization (QBCO). Then the multi-objective optimization problems of multi-relay selection considering SNR maximization and power consumption minimization (two contradictive objectives) or SNR maximization and power efficiency maximization (also two contradictive objectives) are solved based on non-dominated sorting quantum bee colony optimization (NSQBCO), which can obtain the Pareto front solutions considering two contradictive objectives simultaneously. Simulation results show that QBCO based multi-relay selection schemes have the ability to search global optimal solution compared with other multi-relay selection schemes in literature, while NSQBCO based multi-relay selection schemes can obtain the same Pareto front solutions as exhaustive search when the number of relays is not very large. When the number of relays is very large, exhaustive search cannot be used due to complexity but NSQBCO based multi-relay selection schemes can still be used to solve the problems. All simulation results demonstrate the effectiveness of the proposed schemes.

• 한국위성정보통신학회논문지
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• 제9권3호
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• pp.91-97
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• 2014

본 논문은 에너지 검출 기반 협력 스펙트럼 센싱을 이용하여 주사용자와 부사용자 사이의 거리에 따른 검출 확률에 가중치를 부여하는 기법을 제안하고, 이에 따른 분석 및 모의실험 결과를 나타낸다. 주사용자와 부사용자 사이의 거리는 모두 다르다고 가정하였고, 이들 사이의 무선 채널은 레일레이(Rayleigh) 채널로 모델링하였다. 제안하는 가중치 부여 기법을 적용한 협력 스펙트럼 센싱을 수행한 결과가 가중치를 적용하지 않은 스펙트럼 센싱을 수행한 결과에 비해 커버리지를 확대 할 수 있고, 이 검출 확률에 가중치를 적용한 것이 가중치를 적용하지 않은 이전의 방식에 비해 센싱 효율이 향상 되는 것을 알 수 있었다.