• Asian Journal of Innovation and Policy
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• 제4권2호
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• pp.132-153
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• 2015

Rural enterprise clusters in India have often been characterized by low-end products, poor income earning options and a near-absence of innovativeness. This has implied limited market access, inadequate organization of production and distancing from sources of formal knowledge. Policy neglect of rural industrialization notwithstanding this paper explores the nature of institutional constraints to innovation through intensive case studies of five rural artisan clusters (handlooms and handicrafts) in as many Indian states. Whether it relates to access to loan finance or technology support or linking to markets, the formal institutions (public or private) have been distanced by informality that typifies most rural enterprise clusters. An obsession with a sectoral approach to cluster development has negated addressing infirmities of the space of enterprise, even as scope for learning from some Asian economies in rural enterprise promotion exists. The paper also enquires if the innovation systems have been inclusive and pro-poor.

• Journal of Electrical Engineering and Technology
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• 제4권3호
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• pp.337-345
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• 2009

Deregulation in power industry has made the reactive power ancillary service management a critical task to power system operators from both technical and economic perspectives. Reactive power management in power systems is a complex combinatorial optimization problem involving nonlinear functions with multiple local minima and nonlinear constraints. This paper proposes a practical market-based reactive power ancillary service management scheme to tackle the challenge. In this paper a new model for voltage security and reactive power management is presented. The proposed model minimizes reactive support cost as an economic aspect and insures the voltage security as a technical constraint. For modeling validation study, two optimization algorithm, a genetic algorithm (GA) and particle swarm optimization (PSO) method are used to solve the problem of optimum allocation of reactive power in power systems under open market environment and the results are compared. As a case study, the IEEE-30 bus power system is used. Results show that the algorithm is well competent for optimal allocation of reactive power under practical constraints and price based conditions.

• 전자공학회논문지B
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• 제30B권4호
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• pp.11-20
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• 1993

In the new database applications such as office information systems, CAD/CAM, and AI, it is required to support not only fixed Is-A and Part-Of relationships but also various user-defined dynamic relationships including complicate constraints. However, existing object-oriented systems have many weaknesses in managing those complex relationships. This paper presents the Object-Oriented Relationship data Model (OORM) which is designed to provide facilities for modeling complex relationships into object oriented databases using abstraction concept. In the model, various integrity and consistency constraints related to the relationships can be also represented. And this paper presents a query language, ORSQL(Object Relationship SQL). ORSQL is a nonprocedural query language having similiar syntax to the standard SQL and supporting OORM's operations.

• 조명전기설비학회논문지
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• 제23권2호
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• pp.182-189
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• 2009

경쟁적 전력시장에서 발전회사의 전략적 행위를 분석하기 위해서 일반적으로 내쉬균형(Nash equilibrium) 이론이 널리 사용되고 있다. 기존 연구에 의하면 송전제약이 있는 전력시장에서는 최적반응의 불연속으로 인해 순수전략내 쉬균형이 존재하지 않게 되고, 이때는 혼합전략 내쉬균형이 전력시장의 균형이 된다. 본 논문에서는 송전제약이 있는 2-지역 전력시장에서 혼합전략 내쉬균형을 유도하고, 송전용량이 혼합전략 내쉬균형에 미치는 영향을 해석하였다.

• Journal of Communications and Networks
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• 제7권1호
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• pp.87-92
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• 2005

This paper presents basic queueing analysis contributing to teletraffc theory, with commonly accessible mathematical tools. This paper studies queueing systems with bulk arrivals. It is assumed that the number of arrivals and the expected number of arrivals in each bulk are bounded by some constraints B and (equation omitted), respectively. Subject to these constraints, convexity argument is used to show that the bulk-size probability distribution that results in the worst mean queue performance is an extremal distribution with support {1, B} and mean equal to A. Furthermore, from the viewpoint of security against denial-of-service attacks, this distribution remains the worst even if an adversary were allowed to choose the bulk-size distribution at each arrival instant as a function of past queue lengths; that is, the adversary can produce as bad queueing performance with an open-loop strategy as with any closed-loop strategy. These results are proven for an arbitrary arrival process with bulk arrivals and a general service model.

• Journal of Electrical Engineering and information Science
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• 제2권5호
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• pp.89-99
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• 1997

The application for real-time database systems must satisfy timing constraints. Typically the timing constraints are expressed in the form of deadlines which are represented by priorities to e used by schedulers. In any real-time applications, since the system maintains sensitive information to be shared by multiple users with different levels of security clearance, security is another important requirement. As more advanced database systems are being used in applications that need to support timeliness while managing sensitive information, protocols that satisfy both requirements need to be developed. In this appear, we proposed a new priority-driven secure multiversion locking (PSMVL) protocol for real-time secure database systems. The schedules produced by PSMVL are proven to e one-copy serializable. We have also shown tat the protocol eliminates covert channels and priority inversions. The details of the protocol, including the compatibility matrix and the version selection algorithms are presented. the results of the performance comparisons of our protocol with other protocols are described.

• Industrial Engineering and Management Systems
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• 제9권2호
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• pp.178-194
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• 2010

To improve the ship operation in automated container terminals, it is important to schedule different types of handling equipment to operate synchronously. For example, a vehicle with container receiving and lifting capabilities is used to transport containers from a storage yard to a vessel and vice versa, while a triple quay crane (QC) can handle up to three 40-ft containers simultaneously. This paper discusses the manner in which vehicles should be assigned to containers to support such multi-lifts of QCs by using information about the locations and times of deliveries. A mixed-integer programming model is introduced to optimally assign delivery tasks to vehicles. This model considers the constraint imposed by the limited buffer space under each QC. A procedure for converting buffer-space constraints into time window constraints and a heuristic algorithmfor overcoming the excessive computational time required for solving the mathematical model are suggested. A numerical experiment is conducted to compare the objective values and computational times of the heuristic algorithm with those of the optimizing method to evaluate the performance of the heuristic algorithm.

• 융합경영연구
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• 제7권3호
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• pp.43-49
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• 2019

Purpose - This paper empirically investigates what factors contribute to management decisions by corporate governance in the Korean stock market. In the paper, dividends and investments were imployed as management decisions and major stockholders' shares and foreign investors' shares were used as corporate governance. Research design, data, and Methodolog - Samples are constructed by manufacturing firms listed on the stock market of Korea as well as those who settle accounts in December from 2001 to 2018. Financial institutions are excluded from the sample as their accounting procedures, governance and regulations differ. This study adopted the panel regression model to assess the sample construction including yearly and cross-sectional data. Results - This results support the literatures that major shareholders showed insignificance to dividends, positive significance to investment in financially unconstrained firms and negative significance to investment in financially constrained firms. Whereas foreign investors favor firms to increase dividends but they decrease investments only in financially constrained firms. Conclusion - This paper documented evidence that financial constrained firms use dividends for their investment and foreign investors decrease investments under financial constraints. But for dividends decisions, foreign investors give significant positive impacts irrespective of financial constraints.

• 디지털융복합연구
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• 제11권3호
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• pp.181-187
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• 2013

공급자와 소비자간의 정보공유는 기능 중심에서 프로세스 중심이 되면서, 유연성과 고객 서비스를 극대화하기 위한 새로운 물류 개념을 요구하게 되었다. 다시 말하면 원부자재의 조달에서부터 생산을 거쳐 고객에게 판매되기까지의 전 과정에 걸친 개체간의 수요와 공급의 사슬관계를 의미하는 공급망 내에서 정보, 자금 그리고 물의 흐름을 관리 통제하는 공급사슬경영(SCM)이 사업의 핵심역량으로 인식되고 있다. 또한 국내 기업들의 수 배송 업무의 합리화는 국내 기업 물류관리의 가장 중요한 과제중의 하나로 부각되고 있다. 물류센터로부터 각 거래처로 물품을 배달하는 배송업무의 경우에는 기업의 물류정보시스템이 상류 중심의 데이터 체계로 구축되어왔기 때문에 물류관리 업무의 합리화에 활용할 수 있는 기초 데이터 부재와 현실적인 제약조건들을 고려한 효율적인 자동배차 알고리듬을 적용하지 못했기 때문에 배차담당자들의 수작업 조정시간이 장시간 소요되었다. 따라서 본 논문에서는 현실적인 다양한 제약조건을 만족하고, 수작업 조정시간이 대폭 줄이면서, 우편중심 좌표를 이용한 차량별 근거리 그룹핑으로 자동배차 지원시스템의 휴리스틱 알고리듬을 설계하도록 한다.

• 한국해양공학회지
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• 제24권1호
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• pp.20-33
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• 2010

The paper deals with strength design of a riser support installed on floating production storage and offloading (FPSO) vessel under various loading conditions - operation, extreme, damaged, one line failure case (OLFC) and installation. The design problem is formulated such that thickness sizing variables are determined by minimizing the weight of a riser support structure subject to stresses constraints. The initial design model is generated based on an actual FPSO riser support specification. The finite element analysis (FEA) is conducted using MSC/NASTRAN, and optimal solutions are obtained via moving least squares method (MLSM) in the context of response surface based approximate optimization. For the meta-modeling of inequality constraint functions of stresses, a constraint-feasible moving least squares method (CF-MLSM) is used in the present study. The method of CF-MLSM, compared to a conventional MLSM, has been shown to ensure the constraint feasibility in a case where the approximate optimization process is employed. The optimization results present improved design performances under various riser operating conditions.