• Journal of Power Electronics
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• 제14권2호
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• pp.315-323
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• 2014

An optimized space vector pulse width modulation (SVPWM) method with common mode voltage elimination and neutral point potential balancing is proposed for an open-end winding induction motor. The motor is fed from both of the ends with two neutral point clamped (NPC) three-level inverters. In order to eliminate the common mode voltage of the motor ends and balance the neutral point potential of the DC link, only zero common mode voltage vectors are used and a balancing control factor is gained from calculation in the strategy. In order to improve the harmonic characteristics of the output voltages and currents, the balancing control factor is regulated properly and the theoretical analysis is provided. Simulation and experimental results show that by adopting the proposed method, the common mode voltage can be completely eliminated, the neutral point potential can be accurately balanced and the harmonic performance for the output voltages and currents can be effectively improved.

• 한국항공우주학회지
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• 제32권7호
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• pp.69-75
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• 2004

비행중인 다른 항공기를 회피하며 항공기를 목표점까지 유도하는 문제를 2차원 평면에서 고려하였다. 항공기는 속도의 크기가 일정한 질점이며, 제어입력으로 측가속도를 사용하는 것으로 가정하였다. 이동장애물에는 척력 포텐셜함수를 목적점에는 인력 포텐셜함수를 인공적으로 부여하여 항공기에 척력과 인력이 작용하도록 하였다. 유도/회피명령은 이들 포텐셜력과 상대속도를 사용하여 실시간으로 구현 가능한 유도/회피법칙을 구현하였다. Log 형태의 포텐셜함수를 사용하면 구현된 유도법칙은 잘 알려진 비례항법유도법칙이 되며, 회피법칙은 장애물까지 도달시간에 반비례하고 시선각 변화의 반대 방향으로 항공기를 회전시킨다. 제안된 유도/회피법칙은 시뮬레이션을 통하여 타당성을 검증하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권8호
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• pp.3606-3629
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• 2018

The discovered high potential utility itemsets (HPUIs) have significant influence on a variety of areas, such as retail marketing, web click analysis, and biological gene analysis. Thus, in this paper, we propose an algorithm called HPUIM-QGA (Mining high potential utility itemsets based on a quantum genetic algorithm) to mine HPUIs over uncertain datasets based on a quantum genetic algorithm (QGA). The proposed algorithm not only can handle the problem of the non-downward closure property by developing an upper bound of the potential utility (UBPU) (which prunes the unpromising itemsets in the early stage) but can also handle the problem of combinatorial explosion by introducing a QGA, which finds optimal solutions quickly and needs to set only very few parameters. Furthermore, a pruning strategy has been designed to avoid the meaningless and redundant itemsets that are generated in the evolution process of the QGA. As proof of the HPUIM-QGA, a substantial number of experiments are performed on the runtime, memory usage, analysis of the discovered itemsets and the convergence on real-life and synthetic datasets. The results show that our proposed algorithm is reasonable and acceptable for mining meaningful HPUIs from uncertain datasets.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.132-141
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• 2011

Australia has joined many governments to adopt public-private partnership (PPP) as a major strategy for procuring infrastructure for decades. However, failures have occurred although the market has been considered to be a mature and sophisticated one. Failures have typically been traced back to inappropriate economic evaluation and a lack of value-for-money. In particular, a literature review has identified that there was no holistic consideration on the evaluation of procurement transactions of PPP projects. The transaction costs of PPPs were not handled properly. In this paper, theories of transaction cost economics are proposed for the purpose of such a holistic institutional economic evaluation. These theories are analysed in order to identify potential critical success factors for a strategic infrastructure procurement framework. The potential critical success factors are identified and grouped into a number of categories that match the theories of transaction cost economics. These categories include (1) Asset Specificity, (2) Organizational Capability, (3) Transaction Frequency, (4) Behavioural Uncertainty, and (5) Environmental Uncertainty. These potential critical success factors may be subject to an empirical test in the future. The proposed framework will offer decision makers with an insight into project life cycle economic outcomes needed to successfully deliver PPPs.

• 농촌계획
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• 제17권3호
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• pp.91-101
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• 2011

The purpose of this study is to suggest a landscape resources evaluation strategy of rural waterfront villages along the river. This strategy consists of three phases: 1) an evaluation of rural amenity landscape resources, 2) an evaluation of water landscape resources, and 3) development of a positioning map based on the results of phase 1) and 2) the study result as follows. First, the evaluation method used in phase 1) was modified as a set of proposed evaluation indicators to assess development potential on rural waterfront villages. Second, to evaluate water landscape resources in rural waterfront villages, a series of evaluation index was developed including water area, diversity of water resources, biodiversity, and landscape quality. And the last, the positioning map showed relative position of waterfront villages obtained from two evaluation results: rural amenity landscape resources and water landscape resources. The study examined the proposed strategy as a possible alternative to evaluate landscape quality to 398 rural waterfront villages along the Han River. Landscape resources evaluation strategy proposed here could contribute to government officials and planners to operate systematic planning and management of rural waterfront villages.

• 대한지역사회영양학회지
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• 제19권1호
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• pp.51-59
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• 2014

The current exploratory study presents the Analytical Hierarchy Process (AHP) as a potential decision-making method to obtain the relative weights of alternatives through pairwise comparison in the context of hierarchical structure. The aim of this study was to elicit prior strategy to improve army military foodservice. Content analysis and seven times of in-depth interview from 13 officers of the Ministry of National Defense were conducted to develop the hierarchical structure for AHP analysis. Questionnaires were distributed to 61 foodservice managers and 39 dietitian and military foodservice officers. The highest-ranked strategy for improving military foodservice was the 'renewal of the kitchen facilities' (0.2578), followed by 'enlargement of foodservice operating staffs' (0.2345), 'specialization of sanitation & foodservice management' (0.2222), 'Practical foodservice budget control' (0.1394), and 'menu variety & standardized recipe' (0.1281). 'Enlargement of foodservice facilities' (0.3995), 'increase the no. of kitchen police' (0.3463), 'sanitary & cooking training reinforcement of kitchen police' (0.4445), 'management of foodservice budget by total amount' (0.5043), and 'standardization of mass cooking' (0.3571) were the highest overweight item in each strategy. The study also compared the relative weights of alternatives of foodservice managers with that of dietitians and military foodservice officers. Those two groups revealed some difference in their priority of important strategy regarding army military foodservice. The results of this study would provide the data for making a policy or compilation of the budget regarding army military foodservice.

• Journal of Microbiology and Biotechnology
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• 제25권2호
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• pp.185-195
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• 2015

Glucoamylase is an important industrial enzyme. Glucoamylase production by industrial Aspergillus niger strain featured with two major problems: (i) empirical substrate feeding methods deteriorating the fermentation performance; and (ii) the high raw materials cost limiting the economics of the glucoamylase product with delegated specification. In this study, we first proposed a novel three-stage varied-rate substrate feeding strategy for efficient glucoamylase production in a 5 L bioreactor using the standard feeding medium, by comparing the changing patterns of the important physiological parameters such as DO, OUR, RQ, etc., when using different substrate feeding strategies. With this strategy, the glucoamylase activity and productivity reached higher levels of 11,000 U/ml and 84.6 U/ml/h, respectively. The performance enhancement in this case was beneficial from the following results: DO and OUR could be controlled at the higher levels (30%, 43.83 mmol/l/h), while RQ was maintained at a stable/lower level of 0.60 simultaneously throughout the fed-batch phase. Based on this three-stage varied-rate substrate feeding strategy, we further evaluated the economics of using alternative carbon sources, attempting to reduce the raw materials cost. The results revealed that cornstarch hydrolysate could be considered as the best carbon source to replace the standard and expensive feeding medium. In this case, the production cost of the glucoamylase with delegated specification (5,000 U/ml) could be saved by more than 61% while the product quality be ensured simultaneously. The proposed strategy showed application potential in improving the economics of industrial glucoamylase production.

• 한국융합학회논문지
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• 제13권4호
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• pp.397-407
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• 2022

본 연구는 산업 내에서 모방적인 경영전략을 표방하지 않고 차별화된 전략을 수행하는 기업의 미래 성과 혹은 기업가치의 관련성을 검증하고자 한다. 경영전략은 기업의 발전과 성장 가능성에 중요한 역할을 하며 미래 성과와 기업가치를 결정짓는 요인이기도 하다. 이러한 경영전략은 산업에 따라 차이가 존재하며 동일 업종에서 이질적인 전략은 기업의 미래 성과와 가치에 영향을 줄 수 있다. 본 연구에서는 국내 기업을 대상으로 전략적 일탈 기업들의 미래 성과와 기업가치의 관계를 검증하기 위하여 2011년부터 2019년까지 상장법인을 대상으로 분석을 실시하였다. 검증결과 전략적 일탈은 기업가치에 양(+)의 영향을 미치는 것으로 나타났지만 미래 성과는 음(-)의 영향을 미치며 성과의 지속성에도 영향을 미치는 것으로 나타났다. 이러한 결과들은 전략을 구분하여 전략에 따른 특성이 기업가치, 미래성과 등에 대한 연구를 확대하여 전략적 일탈이 기업가치 혹은 미래성과, 성과의 지속성에 미치는 영향을 검증한 것에 의미가 있는 것으로 보인다.

• 디지털융복합연구
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• 제11권5호
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• pp.13-21
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• 2013

방송통신 컨버전스의 대표 서비스인 IPTV는 21세기 국가 성장동력이 될 수 있는 무한한 잠재력을 지닌 분야이다. 미래지향적인 산업인만큼 IPTV 도입 정책은 근시안적인 시각에서 벗어나 중장기적인 관점에서 수립되는 것이 바람직하다. 이에 본 연구는 컨버전스 환경에서 미리 IPTV 서비스의 변화와 정책 이슈들을 제안하였다. 불확실한 미래의 상황을 예측, 분석하는 미래 연구이기 때문에 이러한 분석에 적합한 것으로 알려져 있는 T.A.I.D.A라는 연구 방법론을 분석에 활용하였다.

• 전기학회논문지
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• 제56권6호
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• pp.1017-1022
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• 2007

In this paper, we try to analyze the likelihood of exercising the power of market dominance by certain generators in future power industry of Korea. Firstly, we estimated installed generation capacity and sales volume of electricity in Korea, based on 'The 3rd Long Term Power Plan' which was announced in December 2006. Secondly, we calculated HHI, an index showing the degree of concentration of an industry, and RSI, an index showing how adequate the supply of goods or services of an industry is, using Fast-Forward. Thirdly, assuming a major generator employs the strategy of withholding a part of its available capacity at a peak time, we simulated hypothetical movement of SMP over a certain period of time, which is compared with that obtained without assuming such strategy to generate Lerner Index. an index showing the degree of market power of a monopoly. Regulators, home and abroad, have not given much interest in analyzing the effect of market dominance that is likely to be exercised by certain players in the future. That said, this paper provides insight into developing methodologies of analyzing and mitigating such effect by proposing the above indices to gauge it. In addition, this paper also shows the potential impact of employing capacity withholding strategy on the financial account of a dominant generator.