• Journal of Korea Multimedia Society
• /
• v.9 no.12
• /
• pp.1560-1571
• /
• 2006

In order to transmit multimedia streams over the network with a timely changing channel bandwidth such as Internet, scalable video coding schemes have been studied to represent video in flexible bitstream. Much research has been made on how to represent encoded media(such as video) bitstream in scalable ways. In this paper, rte propose an optimal selection of the objects for MPEG-4 bitstream adaptation to meet a given constraint. We adopt a multiple choice knapsack problem with multi-step selection for the MPEG-4 objects with different bit-rate scaling levels in the MPEG-4 bitstream. The bitstream adaptation based on the optimal selection result is then to fetch the necessary parts of the MPEG-4 bitstream to constitute an adapted version of the original MPEG-4 binary resource. The experiment results show that the optimal selection of MPEG-4 objects for a given constraint can promisingly be made which meets the given constraint.

• Proceedings of the Korean Information Science Society Conference
• /
• 2007.10d
• /
• pp.407-412
• /
• 2007

본 논문에서는 IEEE 802.16 OFDMA 시스템에서 단말들의 에너지 절약을 위한 효율적인 상향 링크 자원 할당 알고리즘을 제시한다. 기지국은 각각의 단말들이 상향링크로 데이터를 전송할 수 있도록 상향링크 부프레임에 연속적인 형태의 자원을 할당해 줘야 한다. 이렇게 각 단말들의 에너지 소비를 고려하여 효율적으로 자원을 할당하는 방식은 최적화 문제의 형태로 접근할 수 있다. 본 논문에서는 전체 에너지소비가 최소가 되는 자원 할당 문제를 Multiple Choice Knapsack 문제로 정의하고, 이를 효율적으로 풀 수 있는 준최적화 알고리즘을 제시한다. 준최적화 알고리즘은 전체 에너지 소비가 최소가 되는 각 단말들의 최적의 변조로 부호화 기법을 찾는다. 그리고 성능평가를 통해 준최적화 알고리즘이 채널 상태만을 고려하여 변조로 부호화 레벨을 결정하는 기법에 비해 최대 53%의 성능 이득을 보이는 것을 제시한다.

• International Journal of Control, Automation, and Systems
• /
• v.3 no.spc2
• /
• pp.334-340
• /
• 2005

Based on the stability margin provided by the EEAC, the unstable contingencies can be classified into sets according to their unstable modes. This two-part paper develops a globally optimal algorithm for transient stability control to coordinate preventive actions and emergency actions. In the first part, an algorithm is proposed for a set of contingencies having identical unstable modes. Instead of iterations between discrete emergency actions and continuous preventive actions, the algorithm straightforwardly searches for a globally optimal solution. The procedure includes assessing a set of insufficient emergency schemes identified by the EEAC; calculating the related preventive actions needed for stabilizing the system; and selecting the scheme with the minimum overall costs. Simulations on a Chinese power system highlight its excellent performance. The positive results obtained are explained by analogizing settlements for 0-1 knapsack problems using the multi-points greedy algorithm.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.14 no.5
• /
• pp.2003-2021
• /
• 2020

Today's computer systems are widely integrated with CPU and GPU to achieve considerable performance, but energy consumption of such system directly affects operational cost, maintainability and environmental problem, which has been aroused wide concern by researchers, computer architects, and developers. To cope with energy problem, we propose a task-scheduling framework to reduce energy under performance constraint by rationally allocating the tasks across the CPU and GPU. The framework first collects the estimated energy consumption of programs and performance information. Next, we use above information to formalize the scheduling problem as the 0-1 knapsack problem. Then, we elaborate our experiment on typical platform to verify proposed scheduling framework. The experimental results show that our proposed algorithm saves 14.97% energy compared with that of the time-oriented policy and yields 37.23% performance improvement than that of energy-oriented scheme on average.

• Journal of Communications and Networks
• /
• v.16 no.5
• /
• pp.559-567
• /
• 2014

In this paper, a framework for power allocation of downlink transmissions in orthogonal frequency division multiple access-based decode-and-forward cellular relay networks is investigated. We consider a system with a single base station communicating with multiple users assisted by multiple relays. The relays have limited power which must be divided among the users they support in order to maximize the data rate of the whole network. Advanced power allocation schemes are crucial for such networks. The optimal relay power allocation which maximizes the data rate is proposed as an upper bound, by finding the optimal power requirement for each user based on knapsack problem formulation. Then by considering the fairness, a new relay power allocation scheme, called weighted-based scheme, is proposed. Finally, an efficient power reallocation scheme is proposed to efficiently utilize the power and improve the data rate of the network. Simulation results demonstrate that the proposed power allocation schemes can significantly improve the data rate of the network compared to the traditional scheme.

• Proceedings of the IEEK Conference
• /
• 2007.07a
• /
• pp.63-64
• /
• 2007

The Underwater Wireless Sensor Networks (UWSN) consists of sensor nodes equipped with limited sensing coverages, energy resources and communication capacity. Hence, the deployment and movement algorithm is a key issue that needs to be organized in order to improve the sensing efficiency of the networks. In this paper, we use a Queen problem and Knapsack problem to prevent the reiteration phenomenon of sensors, to guarantee improvement sensing coverage and efficiency in the 3D UWSN.

• Industrial Engineering and Management Systems
• /
• v.3 no.1
• /
• pp.22-37
• /
• 2004

An integrated heuristic approach based on genetic algorithms (GAs) is proposed for solving the container selection and loading problems. The GA for container selection solves a two-dimensional knapsack problem, determining a set of containers to minimize the transportation or shipment cost. The GA for container loading solves for the weighted coefficients in the evaluation functions that are applied in selecting loading positions and boxes to be loaded, so that the volume utilization is maximized. Several loading constraints such as box orientation, stack priority, stack stability, and container stability are also incorporated into the algorithm. In general, our computational results based on randomly generated data and problems from the literature suggest that the proposed heuristic provides a good solution in a reasonable amount of computational time.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.2
• /
• pp.157-164
• /
• 2006

This paper addresses the design of container liner shipping service networks by explicitly taking into account empty container repositioning and container fleet size. Two key and interrelated issues of deployments of ships and containers are usually treated separately by most existing studies on shipping network design. In this paper, both issues are considered simultaneously. The problem is formulated as a two-stage problem: the upper-problem being formulated as a Knapsack problem and the lower-problem as a Flow problem. A genetic algorithm based heuristic is developed for the problem. Through a number of numerical experiments that were conducted it was shown that the problem considering empty container repositioning provides a more insightful solution than the one without.

• Journal of the Institute of Convergence Signal Processing
• /
• v.4 no.3
• /
• pp.61-67
• /
• 2003

We propose a systolic array for dynamic programming which is a technique for solving combinatorial optimization problems. We derive a systolic array for single source shortest path Problem, SA SSSP, and then show that the systolic array serves as dynamic Programming systolic array which is applicable to any dynamic programming problem by developing a systolic array for 0 1 knapsack problem, SA 01KS, with SA SSSP for a basis. In this paper, each of SA SSSP and SA 01KS is modeled and simulated in RT level using VHDL, then synthesized to a schematic and finally implemented to a layout using the cell library based on 0.35${\mu}{\textrm}{m}$ 1 poly 4 metal CMOS technology.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2012.11a
• /
• pp.1728-1731
• /
• 2012

본 논문에서는 부모 개체의 해밍 거리에 기반하여 선택적 변이연산을 적용한 유전알고리즘을 제안한다. 유전자 형이 매우 유사한 개체들 간의 유전연산은 알고리즘의 탐색성능을 저하시키고 조기 수렴의 가능성을 증가시킨다. 본 논문에서는 이러한 현상을 극복하기 위하여, 교차연산 시 선택된 두 부모 개체간의 해밍 거리에 따라 그 값이 낮으면 교차연산 후 생성된 두 자식 개체 중 한쪽에게 높은 변이확률을 적용하고 다른 한쪽 자식은 부모와 비슷한 유전자 형으로 탐색을 계속하게 하여 조기 수렴을 방지하면서 해집단의 다양성 유지 기능을 향상 시켰다. 제안한 유전 알고리즘을 다차원 배낭 문제에 적용한 결과, 같은 조건에서 단순 유전 알고리즘(SGA) 보다 향상된 탐색 성능을 보여주었다.