• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.7
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• pp.36-44
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• 2010

When multi-user MIMO (Multiple-Input Multiple-Output) systems utilize a sum-rate maximization (SRM) scheduler, the throughput of the systems can be enhanced. However, fairness problems may arise because users located near cell edge or experiencing poor channel conditions are less likely to be selected by the SRM scheduler. In this paper, a weighted sum-rate maximization (WSRM) scheduler is used to enhance the fairness performance of the MIMO systems. Closed-form expressions for the optimal transmit power allocation of WSRM and corresponding weighted sum-rate (WSR) are derived in the 6-sector collaborative transmission system. Using the derived results, we propose an algorithm which searches the optimal power allocation for WSRM in the 3-sector collaborative transmission system. Based on the derived closed-form expressions and the proposed algorithm, we perform computer simulations to compare performance of the WSRM scheduler and the SRM scheduler with respect to the sum-rate and the log-sum-of-average rates. We further verify that the WSRM scheduler efficiently improves fairness performance by showing the enhanced performance of average transmission rates in low percentile region.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.6
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• pp.663-669
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• 2004

A nuclear power plant is composed of a number of primary components. Maintaining the integrity of these components is one of the most critical issues in nuclear industry. In order to maintain the integrity of these primary components, a complicated procedure is required including regular in-service inspection, failure assessment, fracture mechanics analysis, etc. Also, experts in different fields have to co-operate to resolve the integrity issues on the basis of inspection results. This integrity evaluation process usually takes long, and thus, is detrimental for the plant productivity. Therefore, an effective safety evaluation system is essential to manage the integrity issues on a nuclear power plant. In this paper, a web-based fatigue life evaluation system for primary components in nuclear power plant is proposed. This system provides engineering knowledge-based information and concurrent and collaborative working environment through internet, and thus, is expected to raise the efficiency of integrity evaluation procedures on primary components of a nuclear power plant.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.369-371
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• 2011

Since users can experience new type of experiment system using augmentation technology and its data visibility, it is a media that is suited to educational purpose application. This paper developed an augmentation-based experimentation that excludes risks and ehnances immersion in chemical experiment. This virtual chemistry experiment system utilizes users' hands to control 3D objects in experiment through interface that interacts virtual objects without markers that are the cause of losing immersion in existing augmentation system. To maximize immersion effect, we propose a virtual chemistry experiment system that enables collaborative work.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.279-284
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• 2003

A nuclear power plant is composed of a number of primary components. Maintaining the integrity of these components is one of the most critical issues in nuclear industry. In order to maintain the integrity of these primary components, a complicated procedure is required including regular in-service inspection, failure assessment, fracture mechanics analysis, etc. Also, experts in different fields have to co-operate to resolve the integrity issues on the basis of inspection results. This integrity evaluation process usually takes long, and thus, is detrimental for the plant productivity. Therefore, an effective safety evaluation system is essential to manage the integrity issues on a nuclear power plant. In this paper, a web-based fatigue life evaluation system for primary components in nuclear power plant is proposed. This system provides engineering knowledge-based information and concurrent and collaborative working environment through internet, and thus, is expected to raise the efficiency of integrity evaluation procedures on primary components of a nuclear power plant.

• The KIPS Transactions:PartD
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• v.11D no.6
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• pp.1301-1310
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• 2004

In distributed office, the pairs can program together using a distributed pair programming system. Many CSCW tools featuring remote screen sharing function have insufficient usability, accessibility to introduce many developers to distributed pair programming. In this paper, we suggest a distributed pair programming system based on IDE, which many developers will accept and use easily. We have do#eloped a user scenario and GUI of the system, making distributed pair programming easier and designed with high extensibility by adapting design patterns and implemented in Java language. Our findings will be of significant help to developers dealing with implementation of distributed pair programming function into some commercial IDE.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.315-318
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• 2003

In Korea construction project case, architectural construction project is curtailed production because information network process within multidisciplinary isn't smooth. Particularly, the construction is not insufficient about performance, cost and material, construction process, etc. in result various question arises because of design error in construction step. And various mistake is made because communication path within multidisciplinary isn't smooth in architectural design and design change process. Therefore The final object of this study is to propose the establishment method of decision support process for the cooperative design in order to provides improved design coordination and optimize the building system.

• Korean Journal of Computational Design and Engineering
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• v.11 no.3
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• pp.164-171
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• 2006

As collaborative design and configuration design are of increasing importance in product development, it becomes essential to exchange the feature and parametric CAD models among participants. A history-based parametric method has been proposed and implemented. But each translator which exchanges the feature and parametric information tends to be heavy because to implement duplicated functions such as the identification of the selected geometries, mapping between features which have different attributes. Furthermore. because the history-based parametric translator uses the procedural model as the neutral format, which is the XML macro file, the history-based parametric translators need a geometric modeling kernel to generate an internal explicit geometric model. To ease the problem, we implemented a shared integration platform, the TransCAD. The TransCAD separates translators from the XML macro files. The translators for various CAD systems need to communicate with only the TransCAD. To support the communication with the TransCAD, we exposed the functions of the TransCAD by using the Automation APIs, which is developed by Microsoft. The Automation APIs of the TransCAD consist of the part modeling functions, the data extraction functions, and the utility functions. Each translator uses these functions to translate a parametric CAD model from the sending CAD system into the XML format, or from the in format into the model of the receiving CAD system This paper introduces what the TransCAD is and how it works for the exchange of the feature and parametric models.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.3
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• pp.225-232
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• 2010

글로벌 IS 소싱이 확산됨에 따라 다국적 팀원들로 구성된 글로벌 프로젝트 팀이 급격히 늘어나고 있다. 상이한 시간대에 위치한 팀원 간의 상호작용이 필수적인 글로벌 프로젝트는 이러한 시간적, 공간적 복잡성 때문에 프로젝트의 성공적 수행에 많은 어려움을 겪고 있다. 본 연구는 성공적인 글로벌 프로젝트 수행에 필요한 프로젝트 관리 역량에 대한 탐색적인 연구 조사를 하고자 한다. 본 연구는 글로벌 프로젝트 관리 역량을 정보 기술적 역량(IT capability)과 인적 자원 역량(human resource capability)의 관점에서 고찰하였다. 연구 결과에 따르면 기술적 역량으로는 팀원 간의 조정 및 지식 공유 등을 지원하는 협업 도구(collaborative tools)가 프로젝트 성공에 중요한 역할을 하고, 인적 자원 역량과 관련해서는, 기존에 중요시 여겨지던 기술적 지식들 보다는 경영학적 관리 지식 및 의사 소통 능력 등이 중요시 여겨지는 것으로 나타났다. 인적 역량의 관점에서, 본 연구 결과는 해외소싱이 활발해 짐에 따라 프로젝트 관리자(Project Manager, PM)들이 가져야 하는 주요지식으로 기존의 기술적 지식의 비중은 급격히 줄어든 반면, 의사소통 능력, 해외개발 인력관리, 소싱전략 등과 같은 관리에 대한 지식과 비즈니스 업무지식이 점차 중요해 지고 있음을 보여주고 있다. 한국의 해외 소성은 매우 초기 단계에 있지만 본 연구는 차제에 한국의 IT 인력 특히 PM 인력들이 갖추어야 하는 지식요건과 해외소성을 관리하기 위한 기술적 역량 등에 대한 방향을 제시하고 있다는 점에서 의의가 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.7
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• pp.3414-3434
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• 2016

Classical key generation is complicated to update and key distribution generally requires fixed infrastructures. In order to eliminate these restrictions researchers have focused much attention on physical-layer (PHY-layer) based key generation methods. In this paper, we present a PHY-layer fingerprints based fuzzy key generation scheme, which works to prevent primary user emulation (PUE) attacks and spectrum sensing data falsification (SSDF) attacks, with multi-node collaborative defense strategies. We also propose two algorithms, the EA algorithm and the TA algorithm, to defend against eavesdropping attacks and tampering attacks in mobile cognitive radio networks (CRNs). We give security analyses of these algorithms in both the spatial and temporal domains, and prove the upper bound of the entropy loss in theory. We present a simulation result based on a MIMO-OFDM communication system which shows that the channel response characteristics received by legitimates tend to be consistent and phase characteristics are much more robust for key generation in mobile CRNs. In addition, NIST statistical tests show that the generated key in our proposed approach is secure and reliable.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.611-627
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• 2017

For enhancing the coverage of wireless networks and increasing the spectrum efficiency, small cell networks (SCNs) are considered to be one of the most prospective schemes. Most of the existing literature on resource allocation among non-cooperative small cell base stations (SBSs) has widely drawn close attention and there are only a small number of the cooperative ideas in SCNs. Based on the motivation, we further investigate the cooperative approach, which is formulated as a coalition formation game with power control algorithm (CFG-PC). First, we formulate the downlink sub-channel resource allocation problem in an SCN as a coalition formation game. Pareto order and utilitarian order are applied to form coalitions respectively. Second, to achieve more availability and efficiency power assignment, we expand and solve the power control using particle swarm optimization (PSO). Finally, with our proposed algorithm, each SBS can cooperatively work and eventually converge to a stable SBS partition. As far as the transmit rate of per SBS and the system rate are concerned respectively, simulation results indicate that our proposed CFG-PC has a significant advantage, relative to a classical coalition formation algorithm and the non-cooperative case.