• 정보처리학회논문지A
• /
• 제8A권4호
• /
• pp.517-522
• /
• 2001

웹의 등장은 멀티미디어 기술 및 컴퓨터 통신 기술 개발의 가속화 및 이를 응용한 컨텐츠 개발에 촉진제 역할을 하게되었다. 또한 웹기반 교육 시스템의 연구에서도 전자도서관과 LOD 기술을 접목한 연구들이 활발히 진행되어 왔다. 최근에는 교수-학습 활동에서의 새로운 형태인 웹을 기반으로 한 교육(WBI : Web-Based Instruction)이라는 교수 모형이 제시되기에 이르렀다. 또한, 학습자의 요구에 맞는 코스웨어의 주문이 증가되고 있는 추세이며 그에 따라 웹 기반 교육 시스템에 효율적이고 자동화된 교육 에이전트의 필요성이 인식되고 있다. 그러나 현재 연구되고 있는 많은 교육 시스템들은 학습자 성향에 맞는 코스를 적절히 서비스해 주지 못할 뿐 아니라 지속적인 피드백과 학습자가 코스를 학습함에 있어서 취약한 부분을 재학습 할 수 있도록 도와주는 서비스를 원활히 제공하지 못하고 있다. 본 논문에서는 취약성 분석 알고리즘을 이용한 학습자 중심의 코스 스케쥴링 멀티 에이전트 시스템의 설계를 제안한다. 제안한 시스템은 먼저 학습자의 학습을 지속적으로 모니터링하고 평가하여 개인 학습자의 학습 성취도를 계산하며, 이 성취도를 에이전트의 스케쥴에 적용하여 학습자에게 적합한 코스를 제공하고, 학습자는 이러한 코스에 따라 능력에 맞는 반복된 학습을 통하여 적극적인 완전학습을 수행하게 된다.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2023년도 학술발표회
• /
• pp.28-28
• /
• 2023

Most countries worldwide are finding it difficult to make decisions regarding the utilization of water resources and the ecological flow protection of rivers because of serious water shortages and global climate warming. To overcome this difficulty, accurate ecological flow processes and protected ecological objectives are required. Since the introduction of the concept, ecological flow calculations have been developed for more than 60 years. This technical development has always been dominated by countries such as the United States, Australia, and the United Kingdom. The technical applications, however, vary substantially worldwide. Some countries, for instance, did not readjust the method because of a lack of understanding of the ecological effect or because they failed to achieve elaborate scheduling. Mostly, readjustments were not made because the users could not make their choices from among numerous methods for ecological flow. This paper presents three research results based on a systematic review of 240 methods with clear connotation boundaries. First, the ecological flow algorithm was developed along with the scientific and technological progress in the river ecosystem theory, ecohydrological relationship, and characterization and simulation of hydrological and hydrodynamic processes. In addition, the basis of the method has evolved from the hydrological process of the ecosystem, hydraulics-habitat conditions, and social development interference to whole ecosystem simulation. Second, 240 methods were classified into 50 sub-categories to evaluate their advantages and disadvantages according to the ecological flow algorithms of hydrology, hydraulics, habitat, and other comprehensive methods. According to this evaluation, 60% of the methods were not suitable for further application, including the method based on the percentage of natural runoff. Furthermore, the applicability of the remaining methods was presented according to the evaluation based on the aspects of allocation of water resources, water conservancy project scheduling, and river ecological evaluation. Third, In the future, most developing countries should strengthen the guarantee of high-standard ecological flow via a coordination mechanism for the ecological flow guarantee established under a sustainable framework or via an ecological protection pattern at the national level according to the national system. Concurrently, a reliable ecological flow demand process should also be established on the basis of detailed investigation and research on the relationship between river habitats, ecological hydrology, and ecological hydraulics. This will ensure that the real-time evaluation of ecological flow forces the water conservancy project scheduling and accurate allocation of water.

• 한국산학기술학회논문지
• /
• 제19권4호
• /
• pp.85-92
• /
• 2018

수요관리를 통해 전기요금을 절감할 수 있다. 부하의 수요 관리 방법 중 하나로 ESS를 설치해 수요가 높은 시간대의 부하를 수요가 낮은 시간대로 옮기는 peak shifting을 사용함으로써 최대 부하를 낮추고 전력량 요금을 절감할 수 있다. 전기요금은 계약 용량 당 기본요금과 전력량 요금으로 이루어져있다. 전력량 요금을 최소화하기 위한 최적화 수행시 목적함수는 선형식으로 표현할 수 있으며, 기본 요금 최소화를 위한 목적함수는 이차식으로 표현할 수 있다. 선형식으로 표현된 목적함수에서는 ESS PCS(Power Conversion System)의 충, 방전 효율이 다른 경우를 다룰 수 없기 때문에 본 논문에서 충, 방전 효율이 다른 경우의 영향을 반영하고 혼합정수계획법(MILP, Mixed Integer Linear Programming)을 이용할 수 있는 정식을 제시하였다. 혼합정수계획법을 사용한 정식에서는 사전에 정해진 최대 부하 절감율에 대해 전기요금 최소화를 수행하게 되지만 최대 부하 절감과 전기요금 절감을 동시에 고려하기 위해서는 이차 계획법을 사용하는 것이 유용하다. 본 논문에서는 각 최적화 방법에 대한 장, 단점을 도시철도 변전소에 대한 시뮬레이션 결과를 정량적으로 비교분석하여 ESS 설비계획수립에 적합한 최적화 방법을 선택할 수 있는 근거를 제시하였다.

• 한국통신학회논문지
• /
• 제27권11C호
• /
• pp.1112-1123
• /
• 2002

멀티미디어 서비스 제공에는 네트워크의 효율적인 대역폭 할당 스케줄링이 요구된다. 비디오 데이터 스트림 같은 burstiness 특성을 갖는 정보를 전송하기 위해서는 전송률의 변화를 감소시키는 smoothing 기법을 사용하게 되는데, 현재까지 제안된 최적 smoothing 알고리즘은 peak rate를 크게 줄이고 있지만, 각각의 독립적인 데이터 스트림에 적용되었기 때문에, 네트워크 대역폭이나 프로세서 등을 공유하는 다중 스트림에 사용하기에는 적합하지 않다. 본 논문에서는 이러한 문제점의 해결을 위한 효율적인 대역폭 할당 알고리즘을 제안한다. 대역폭 할당 스케줄링을 정적 대역폭 할당과 동적 대역폭 할당으로 구분해서, 정적 대역폭 할당에서는 사용자 버퍼의 누적 데이터 양을 높게 유지시킴으로써 peak rate를 감소시켰다. 동적 대역폭 할당에서는 real demand factor를 새로운 변수를 이용하여 다중 스트림의 대역폭할당에 적합한 알고리즘을 구현하였다. 마지막으로, 페트리 네트 모의실험 도구인 ExSpect 6.41을 통해서 제안된 알고리즘의 성능을 입증하였다.

• 대한토목학회논문집
• /
• 제38권1호
• /
• pp.167-174
• /
• 2018

본 연구는 현실 적용성을 고려한 버스 최적 배차간격 모형 구축을 통해 현실적 운행계획 작성에 기여하고자 한다. 부산시가 제시한 시내버스 운행계획의 적정성 검토를 통해, 배차간격 및 운행시간이 현실적 여건을 고려하지 않고 계획되어 있음을 파악하였다. 이에 실제 도로 여건과 운행환경을 고려한 운행시간 제약조건과 해당 노선의 수요 충족을 위한 시간대별 배차간격 도출 모형을 구축하였고 부산시 10번과 27번 노선을 사례로 모형의 적용성을 검증하였다. 본 연구는 교통카드 및 BIMS (Bus Information Management System)가 제공하는 방대한 자료(Big-Data)로부터 필요 정보를 추출하였으며, 그 과정에서 분석에 필요한 자료와 정보 추출 과정도 요약 제시하였다. 본 연구의 결과는 현실적 운행계획 작성과 향후 보다 정밀한 여건을 고려한 연구에 기여할 것으로 기대한다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제7권10호
• /
• pp.2479-2496
• /
• 2013

Increasing demand for Full High-Definition (FHD) video and Ultra High-Definition (UHD) video services has led to active research on high speed video processing. Widespread deployment of multi-core systems has accelerated studies on high resolution video processing based on parallelization of multimedia software. Even if parallelization of a specific decoding step may improve decoding performance partially, such partial parallelization may not result in sufficient performance improvement. Particularly, entropy decoding has often been considered separately from other decoding steps since the entropy decoding step could not be parallelized easily. In this paper, we propose a parallelization technique called Integrated Multi-Threaded Parallelization (IMTP) which takes parallelization of the entropy decoding step, with other decoding steps, into consideration in an integrated fashion. We used the Simultaneous Multi-Threading (SMT) technique with appropriate thread scheduling techniques to achieve the best performance for the entire decoding step. The speedup of the proposed IMTP method is up to 3.35 times faster with respect to the entire decoding time over a conventional decoding technique for H.264/AVC videos.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• 제16권4호
• /
• pp.225-237
• /
• 2016

In conventional transportation problem (TP), all the parameters are always certain. But, many of the real life situations in industry or organization, the parameters (supply, demand and cost) of the TP are not precise which are imprecise in nature in different factors like the market condition, variations in rates of diesel, traffic jams, weather in hilly areas, capacity of men and machine, long power cut, labourer's over time work, unexpected failures in machine, seasonal changes and many more. To counter these problems, depending on the nature of the parameters, the TP is classified into two categories namely type-2 and type-4 fuzzy transportation problems (FTPs) under uncertain environment and formulates the problem and utilizes the trapezoidal fuzzy number (TrFN) to solve the TP. The existing ranking procedure of Liou and Wang (1992) is used to transform the type-2 and type-4 FTPs into a crisp one so that the conventional method may be applied to solve the TP. Moreover, the solution procedure differs from TP to type-2 and type-4 FTPs in allocation step only. Therefore a simple and efficient method denoted by PSK (P. Senthil Kumar) method is proposed to obtain an optimal solution in terms of TrFNs. From this fuzzy solution, the decision maker (DM) can decide the level of acceptance for the transportation cost or profit. Thus, the major applications of fuzzy set theory are widely used in areas such as inventory control, communication network, aggregate planning, employment scheduling, and personnel assignment and so on.

• 대한산업공학회지
• /
• 제34권1호
• /
• pp.108-121
• /
• 2008

Dispatching rule for parallel machines with multi product is proposed in this paper, In current market,customer's request for higher quality is increasing, In accordance with such demand, manufacturers are focusingon improving the quality of the products. Such shift in production objective is risky. The possibility ofneglecting another important factor in customer satisfaction increases, namely due dates. From the aspect ofimproving quality, frequency of product assignment to limited number of high performance machines willincrease. This will lead to increased waiting time which can incur delays, In the case of due date orientedproduct dispatch, Products are assigned to machines without consideration for quality. Overall deterioration ofproduct quality is inevitable, In addition, Poor products will undergo rework process which can increase delays.The objective of this research is dispatching products to minimize due date delays while improving overallquality. Quality index is introduced to provide means of standardizing product quality. The index is used toassure predetermined quality level while minimizing product delays when dispatching products. Qualitystandardization method and dispatching algorithm is presented. And performance evaluation is performed withcomparison to various dispatching methods.

• 한국경영과학회지
• /
• 제30권4호
• /
• pp.45-60
• /
• 2005

We consider a vehicle routing problem with time window and dock capacity constraints (VRPTD). In most traditional models of vehicle routing problems with time window (VRPTW), each customer must be assigned to only one vehicle route. However demand of a customer may exceed the capacity of one vehicle, hence at least two vehicles may need to visit the customer We assume that each customer has Its own dock capacity. Hence, the customer can be served by only a limited number of vehicles simultaneously. Given a depot, customers, their demands, their time windows and dock capacities, VRPTD is to get a set of feasible routes which pass the depot and some customers such that all demands of each customer are satisfied Since VRPTD is NP-hard, a meta-heuristic algorithm is developed. The algorithm consists of two Procedures : the route construction procedure and the route scheduling procedure. We tested the algorithm on a number of instances and computational results are reported.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제11권12호
• /
• pp.5712-5728
• /
• 2017

Recently, there are many studies, that considering green wireless cellular networks, have taken the energy consumption of the base station (BS) into consideration. In this work, we first introduce an energy consumption model of multi-mode sharing BS powered by multiple energy sources including renewable energy, local storage and power grid. Then communication load requests of the BS are transformed to energy demand queues, and battery energy level and worst-case delay constraints are considered into the virtual queue to ensure the network QoS when our objective is to minimize the long term electricity cost of BSs. Lyapunov optimization method is applied to work out the optimization objective without knowing the future information of the communication load, real-time electricity market price and renewable energy availability. Finally, linear programming is used, and the corresponding energy efficient scheduling policy is obtained. The performance analysis of our proposed online algorithm based on real-world traces demonstrates that it can greatly reduce one day's electricity cost of individual BS.