• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권5호
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• pp.1567-1587
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• 2014

Virtual Machine (VM) resource management is crucial to satisfy the Quality of Service (QoS) demands of various multimedia services in a media cloud platform. To this end, this paper presents a VM resource allocation model that dynamically and optimally utilizes VM resources to satisfy QoS requirements of media-rich cloud services or applications. It additionally maintains high system utilization by avoiding the over-provisioning of VM resources to services or applications. The objective is to 1) minimize the number of physical machines for cost reduction and energy saving; 2) control the processing delay of media services to improve response time; and 3) achieve load balancing or overall utilization of physical resources. The proposed VM allocation is mapped into the multidimensional bin-packing problem, which is NP-complete. To solve this problem, we have designed a Mixed Integer Linear Programming (MILP) model, as well as heuristics for quantitatively optimizing the VM allocation. The simulation results show that our scheme outperforms the existing VM allocation schemes in a media cloud environment, in terms of cost reduction, response time reduction and QoS guarantee.

• Communications for Statistical Applications and Methods
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• 제6권3호
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• pp.749-754
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• 1999

The cost is known to be proportional to the size of sample. We consider a cost function of the form Cost=c1np+c2npmq where c1, c2 p, and q are all positive constants. This cost function is to be used in finding an optimal allocation in two-stage cluster sampling. The optimal allocations of n and m gives the properties of uniqueness under some conditions and of monotonicity with p>0 when q=1.

• 한국항만경제학회지
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• 제28권4호
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• pp.257-274
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• 2012

글로벌공급사슬간 경쟁이 격화됨에 따라 항만서비스도 항만의 존속과 경쟁력제고를 위한 시장지향적인 가격산정이 크게 필요하다. 협조적 게임이론의 오웬밸류는 선사주체의 시장지향적 항만서비스가격 산정에 활용될 수 있다. 이를 우리나라 광양항의 사례에 적용하여 그 유용성을 확인해보았다. 본 연구결과 부두용 특성함수를 사용하여 선석별 비용배분 문제를 해결하고, Budescu(1993)방법을 통해 안벽사용지수를 구하기 위한 관련요인의 상대적 가중치를 합리적으로 산정하였다. 또한 주요 선사에 대한 사용료 우대방안과 선사간 전략적 제휴에 의한 항만서비스 가격할인방안을 구축하였다. 본 연구를 결과를 활용하여 대형선박을 자주 운항하는 주요 선사에 대한 체계적인 요금할인을 통해 항만서비스요금을 전략적으로 책정 할 수 있을 것이다.

• 한국통신학회논문지
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• 제32권7B호
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• pp.422-430
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• 2007

현재 WDM-PON 기술은 FTTH 구축을 위해 가장 핵심적인 가입자망 기술로 인식되고 있다. 하지만 시스템 비용의 많은 부분을 차지하는 광 송수신기 및 RN과 밀접한 관계가 있는 WDM-PON 시스템 자원의 고정적인 관리방법은 비용 대비 시스템 자원 효율성에 한계점을 가지고 있다. 이에 본 논문에서는 자원의 동적 관리가 가능하면서 이를 위한 시스템의 구축비용 최소화를 이룰 수 있는 WDM-PON 구조를 제안한다. 이를 위해 ONU의 논리그룹화 및 논리그룹 간 파장 공유를 위한 OLT, ONU 그리고 RN의 구조를 설계하고, 이를 기반으로 탄력적인 동적자원 관리를 위한 동적 자원 할당 기법을 제안한다. 이와 같은 WDM-PON 구조의 성능 분석을 위해 모의실험을 수행하였고, 그 결과 논리그룹의 크기와 시스템 구축비용의 상관관계 및 논리그룹 크기와 동적 자원 할당 능력의 상관관계를 도출할 수 있었으며, 자원 관리 기법의 동적 자원 할당 능력과 공평성 유지 능력을 확인할 수 있었다.

• 한국정보처리학회논문지
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• 제6권8호
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• pp.2196-2203
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• 1999

본 논문은 데이터패스 합성에서의 버스 스케줄링 문제와 레지스터의 최적화 방법을 다룬 것이다. 스케줄링은 DFG(Data Flow Graph)의 연산을 제어스텝(control step)에 할당하는 과정으로서, 주어진 조건을 만족하는 범위 내에서 비용함수(cost function)의 최소화에 목적을 둔다. 이를 위해 본 논문에서는, 연산자 배치를 위한 하드웨어 할당(hardware allocation) 과정에서의 설계비용을 최소화시키기 위해, 연산결과를 저장하는 레지스터(register)와 연산간의 이동 통로인 버스(bus)의 최적화 기법을 논하였다. 특히, 하드웨어 할당과정의 중요한 과제인 버스와 레지스터의 최소화 기법을 논하였으며, 레지스터의 최적화는 스케줄링이 완료된 후의 결과를 이용하였다. 실험대상으로는 벤치마크 모델인 5차 디지털 웨이브필터(5th-order digital wave filter)를 사용하였으며, 본 논문의 결과를 기존결과와 비교함으로써, 본 논문의 효용성을 입증하였다. 모든 실험결과는 구조형태의 선형정수계획법(ILP : Integer Linear Programming)을 이용함으로써, 모든 경우에 언제나 최적의 결과를 얻을 수 있도록 하였다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 추계학술대회
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• pp.459-461
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• 2022

Network-on-Chip (NoC) 이 오프칩 네트워크 기반의 기존 병렬처리 시스템과 가장 크게 다른 점은 데이터 패킷 라우팅을 중앙 제어 방식(Centralized control scheme)으로 수행한다는 점이다. 이러한 환경에서 Best-effort 패킷 라우팅 문제는 데이터 패킷이 해당 코어에 도달 및 처리되는 시간을 Cost 로 하는 실시간 최소화 할당 문제(Assignment problem)가 된다. 본 논문에서는 할당 문제의 선형 대수 방정식에 대한 대표적인 연산 복잡도 저감 알고리즘인 헝가리안 알고리즘을 하드웨어 가속기 형태로 구현하였다. TSMC 0.18um 표준 셀라이브러리를 이용하여 논리 합성한 결과 헝가리안 알고리즘의 연산과정을 그대로 구현한 하드웨어 회로보다 Cost 분포에 대한 Case 분석을 통하여 구현한 것이 면적은 약 16%, Propagation delay는 약 52% 감소한 것으로 나타났다.

• 한국기후변화학회지
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• 제9권4호
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• pp.325-342
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• 2018

The Korea Emissions Trading Scheme ( K-ETS), which manages roughly 70% of the greenhouse gas emissions in South Korea, was initiated in 2015, after implementation of its 1st basic plan and the 1st allocation plan (2014) for the 1st phase (2015-2017). During the three and a half years since the launch of K-ETS, there have been critical policy change such as adjustment of the institutions involved, development and revision of the 2030 national GHG reduction roadmap, and change in the allocation plans. Moreover, lack of liquidity and fluctuation of carbon prices in the K-ETS market during this period has forced the Korean government to adjust the flexibility mechanism and auction permits of the market stability reserve. To evaluate the policy change in the K-ETS regarding conformance to its objectives, this study defines three objectives (Environmental Effectiveness, Cost Effectiveness and Economic Efficiency) and ten indicators. Evaluation of Environmental Effectiveness of K-ETS suggests that the national GHG reduction roadmap, coverage of GHG emitters and credibility of MRV positively affect GHG mitigation. However, there was a negative policy change implemented in 2017 that weakened the emission cap during the 1st phase. In terms of the Cost Effectiveness, the K-ETS policies related to market management and flexibility mechanism (e.g. banking, borrowing and offsets) were improved to deal with the liquidity shortage and permit price increase, which were caused by policy uncertainty and conservative behavior of firms during 2016-2018. Regarding Economic Efficiency, K-ETS expands benchmark?based allocation and began auction-based allocation; nevertheless, free allocation is being applied to sectors with high carbon leakage risk during the 2nd phase (2018-2020). As a result, it is worth evaluating the K-ETS policies that have been developed with respect to the three main objectives of ETS, considering the trial?and?error approach that has been followed since 2015. This study suggests that K-ETS policy should be modified to strengthen the emission cap, stabilize the market, expand auction-based allocation and build K-ETS specified funds during the 3rd phase (2021-2025).

• 품질경영학회지
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• 제47권4호
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• pp.701-711
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• 2019

Purpose: The problem of optimizing redundancy allocation in multi-level systems is considered when each item in a multi-level system has alternative items with the same function. The number of redundancy of multi-level system is allocated to maximize the reliability of the system under path set and cost limitation constraints. Methods: Based on cost limitation and path set constraints, a mathematical model is established to maximize system reliability. Particle swarm optimization is employed for redundant allocation and verified by numerical experiments. Results: Comparing the particle swarm optimization method and the memetic algorithm for the 3 and 4 level systems, the particle swarm optimization method showed better performance for solution quality and search time. Particularly, the particle swarm optimization showed much less than the memetic algorithm for variation of results. Conclusion: The proposed particle swarm optimization considerably shortens the time to search for a feasible solution in MRAP with path set constraints. PS optimization is expected to reduce search time and propose the better solution for various problems related to MRAP.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권7호
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• pp.3134-3155
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• 2020

In this paper, we study the joint radio and computational resource allocation in the ultra-dense mobile-edge computing networks. In which, the scenario which including both computation offloading and communication service is discussed. That is, some mobile users ask for computation offloading, while the others ask for communication with the minimum communication rate requirements. We formulate the problem as a joint channel assignment, power control and computational resource allocation to minimize the offloading cost of computing offloading, with the precondition that the transmission rate of communication nodes are satisfied. Since the formulated problem is a mixed-integer nonlinear programming (MINLP), which is NP-hard. By leveraging the particular mathematical structure of the problem, i.e., the computational resource allocation variable is independent with other variables in the objective function and constraints, and then the original problem is decomposed into a computational resource allocation subproblem and a joint channel assignment and power allocation subproblem. Since the former is a convex programming, the KKT (Karush-Kuhn-Tucker) conditions can be used to find the closed optimal solution. For the latter, which is still NP-hard, is further decomposed into two subproblems, i.e., the power allocation and the channel assignment, to optimize alternatively. Finally, two heuristic algorithms are proposed, i.e., the Co-channel Equal Power allocation algorithm (CEP) and the Enhanced CEP (ECEP) algorithm to obtain the suboptimal solutions. Numerical results are presented at last to verify the performance of the proposed algorithms.

• Pediatric Infection and Vaccine
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• 제15권1호
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• pp.20-29
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• 2008

The basis of the economic evaluation of vaccination is the balance between the use of the resources (input) and the improvements that result from the vaccination (output). Techniques used for economic evaluation of vaccination are cost analysis, cost-minimization analysis, cost-effectiveness analysis, cost-utility analysis and cost-benefit analysis. Cost analysis seeks to characterize the costs of a given vaccination program. Cost-effective analysis is to helps policy-makers decide on the best use of allocated resources, whether cost-benefit analysis is to helps policy-makers decide on the overall allocation of resources. Cost-utility analysis is a specific form of cost-effective analysis in which outcomes are reduced to a common denominator such as the quality-adjusted life year (QALY) or disability-adjusted life year (DALY). Many economic analyses have been conducted on vaccines in the world, but there have been a little studies on economic evaluation on vaccines in Korea. This paper reviewed the methodology used to economic evaluation on vaccines and immunizations and addressed some examples of the methods.