• 한국유통학회지:유통연구
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• 제9권1호
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• pp.1-24
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• 2004

As the dot-com companies realize the importance of the traditional business operations such as product distribution and sourcing, the task of balancing business strategy and operations between electronic commerce and"bricks St mortar"channels is an ongoing challenge. However, there are no generic recipes for formulating business strategy that optimally bridges the physical and virtual operations. In order to provide some guidelines, this study examines the big 3 retailers in Korea, and their"clicks ＆ mortar"strategy, assessing how the activities of each channel are integrated to achieve the synergy effect. This study analyzes the differences in the pattern of integration among the three retailers and traces the causes of those differences. It also figures out the relationship between the degree of integration and performance variables such as growth and cost. Finally. it defines the essential constraints on the process of integration along with managerial implications.

• Journal of Power Electronics
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• 제17권6호
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• pp.1625-1636
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• 2017

A power electronic transformer (PET) based on the cascaded H-bridge (CHB) and the isolated bidirectional DC/DC converter (IBDC) is capable of accommodating a large scale battery energy storage system (BESS) in the medium-voltage grid, and is referred to as a power electronic transformer based battery energy storage system (PET-BESS). This paper investigates the PET-BESS and proposes a coordinative control strategy for it. In the proposed method, the CHB controls the power flow and the battery state-of-charge (SOC) balancing, while the IBDC maintains the dc-link voltages with feedforward implementation of the power reference and the switch status of the CHB. State-feedback and linear quadratic Riccati (LQR) methods have been adopted in the CHB to control the grid current, active power and reactive power. A hybrid PWM modulating method is utilized to achieve SOC balancing, where battery SOC sorting is involved. The feedforward path of the power reference and the CHB switch status substantially reduces the dc-link voltage fluctuations under dynamic power variations. The effectiveness of the proposed control has been verified both by simulation and experimental results. The performance of the PET-BESS under bidirectional power flow has been improved, and the battery SOC values have been adjusted to converge.

• Strategy21
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• 통권41호
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• pp.208-231
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• 2017

The balance of power in conventional forces between the two Koreas works in favor of the South Korea in the Korea peninsula. But, the balancing mechanism between the two Koreas in asymmetric forces like nuclear and missile forces works absolutely in favor of the North Korea. That's why it should be timely for the ROK military to review existing strategy and revise a new counter strategy against the threat posed by the North Korea's nuclear and missile forces. The ROK military is now developing 4D, KAMD, KILL Chain strategies as means to cope with the North Korea's nuclear and missile threats. Considering efforts and resources invested now, the strategies are expected to be in place in next five or more years. However, approaches to those strategies seem to be rather fragmentary and conceptual than comprehensive and pragmatic. The types of strategies against the North Korea's military threats need to be a deterrence in peace time and a fighting and winning in war time in the Korean theater. But, the most important element in the deterrence strategy is the credibility. This study concludes with an new strategic concept titled "ADAD(Assured Defense, Assured Destruction)" as an alternative to existing strategies to deal with the North Korea's nuclear and missile threats.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권4호
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• pp.651-669
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• 2013

In this paper, we study a novel routing algorithm based on load balancing for multi-channel wireless mesh networks. In order to increase the network capacity and reduce the interference of transmission streams and the communication delay, on the basis of weighted cumulative expected transmission time (WCETT) routing metric this paper proposes an improved routing metric based on load balancing and channel interference (LBI_WCETT), which considers the channel interference, channel diversity, link load and the latency brought by channel switching. Meanwhile, in order to utilize the multi-channel strategy efficiently in wireless mesh networks, a new channel allocation algorithm is proposed. This channel allocation algorithm utilizes the conflict graph model and considers the initial link load estimation and the potential interference of the link to assign a channel for each link in the wireless mesh network. It also utilizes the channel utilization percentage of the virtual link in its interference range as the channel selection standard. Simulation results show that the LBI_WCETT routing metric can help increase the network capacity effectively, reduce the average end to end delay, and improve the network performance.

• 한국정보통신학회논문지
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• 제9권1호
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• pp.165-171
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• 2005

본 논문에서는 중앙집중형 동적부하균등을 효율적으로 처리하기 위하여 네트워크기반 병렬 유전자 알고리즘을 이용하였다. 기존의 유전자 알고리즘을 적용한 경우와는 달리 클라이언트들에서 최적작업 할당의 탐색을 분산처리하여 중앙 스케줄러의 성능을 향상시킬 수 있었다. 최적해의 수렴속도를 향상시키기 위해 선택연산은 룰렛휠 선택과 엘리트 보존전략을 함께 사용하였고, 염색체 인코딩은 슬라이딩윈도우기법을 이용하였으며 교차연산은 주기교차방법을 이용하였다. 부하균등기법의 유연성 변화에 따른 중앙 스케줄러의 성능을 모의실험한 결과 기존의 방법보다 성능이 향상됨을 확인하였다.

• Industrial Engineering and Management Systems
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• 제15권3호
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• pp.268-277
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• 2016

Load balancing is a significant technique to prolong a network's lifetime in sensor network. This paper introduces a hybrid approach named as Load Distributing Hybrid Routing Protocol (LDHRP) composed with a border node routing protocol (BDRP) and greedy forwarding (GF) strategy which will make the routing effective, especially in mobility scenarios. In an existing solution, because of the high network complexity, the data delivery latency increases. To overcome this limitation, a new approach is proposed in which the source node transmits the data to its respective destination via border nodes or greedily until the complete data is transmitted. In this way, the whole load of a network is evenly distributed among the participating nodes. However, border node is mainly responsible in aggregating data from the source and further forwards it to mobile sink; so there will be fewer chances of energy expenditure in the network. In addition to this, number of hop counts while transmitting the data will be reduced as compared to the existing solutions HRLBP and ZRP. From the simulation results, we conclude that proposed approach outperforms well than existing solutions in terms including end-to-end delay, packet loss rate and so on and thus guarantees enhancement in lifetime.

• 대한산업공학회지
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• 제32권3호
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• pp.200-209
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• 2006

Load building is an important step to make the delivery supply chain efficient. We present a family of load makeup algorithms using market based control strategy, named LoadMarket, in order to build efficient loads where each load consists of a certain number of finished products having destinations. LoadMarket adopts Clark-Wright algorithm for generating initial endowment for Load Traders who cooperate to minimize either total travel distance or the variance with respect to the travel distances of loads by means of the spot market or double-sided auction market mechanism. The efficiency of the LoadMarket algorithms is illustrated using simulation based experiments.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2008년도 추계학술대회 및 정기총회
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• pp.191-196
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• 2008

This paper presents an evolutionary algorithm for goal programming with preemptive priority. To do this, an evolutionary strategy is suggested which search for the solution satisfying the goals in the order of the priority. Two-sided assembly line balancing problems with multiple goals are used to validate the applicability of the algorithm. In the problems, three goals are considered in the following priority order: minimizing the number of mated-stations, achieving the goal level of workload smoothness, and maximizing the work relatedness. The proper evolutionary components such as encoding and decoding method, evaluation scheme, and genetic operators, which are specific to the problem being solved, are designed in order to improve the algorithm's performance. The computational result is reported.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 전력전자학술대회
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• pp.212-213
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• 2017

In this paper is presented a pre-charging sequence for single-phase cascaded neutal-point-clamped(NPC) converters for capacitors voltage balancing. capacitor imbalance problem in pre-charge sequence is caused in cascaded NPC converter by its topology. the DC link voltage at each NPC converter module can be balanced by the proposed switching method. the design and performance of the proposed sequence are verified by simulation and experimental results using prototype.

• Journal of information and communication convergence engineering
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• 제9권5호
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• pp.491-499
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• 2011

In this paper, we offer a new strategic portfolio model for national IT R&D project selection in Korea. A risk and return (R-R) portfolio model was developed using an objectively quantified index on the two axes of risk and return, in order to select a strategic project and allocate resources in compliance with a national IT R&D strategy. We strategize using the R-R portfolio model to solve the non-strategy and subjectivity problems of the existing national R&D project selection model. We also use the quantified evaluation index of the IT technology road map (TRM) and the technical level reports (TLR) for the subjectivity of project selection, and try to discover the weights using the analytic hierarchy process (AHP). In addition, we intend to maximize the chance for a successful national IT R&D project, by selecting a strategic portfolio project and balancing the allocation of resources effectively and objectively.