• Communications for Statistical Applications and Methods
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• 제20권2호
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• pp.137-145
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• 2013

The use of pooled standard deviation can reduce the efficiency loss in optimum allocation when strata standard deviations are estimated and several of them are equal. Also shown is that the pooled standard deviation is useful in optimum allocation under a multivariate setting. In addition to theoretical development, we provide the result of simulation study to support the theory.

• Communications for Statistical Applications and Methods
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• 제10권1호
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• pp.79-88
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• 2003

In this paper, we study the efficiency of the stratified estimator in related with the variance lower bound of Horvitz-Thompson estimator subject to the superpopulation model. Especially, we compare the variance lower bound of optimum allocation with that of power allocation subject to Dalenius-Hedges stratification.

• 산업경영시스템학회지
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• 제5권6호
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• pp.1-6
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• 1982

The objective of this thesis to Provide a better insight into the effect of the amount of in-process storage has on the efficiency of production line with variable operation times. It is assumed that the material enters the line at the first work station and is then processed progressively through the line until it exits at the last work station, a finite amount of in-process storage is provided before all but the first work station of the line and the operation time of the work stations are statistically independent and follow exponential distribution. Under the above assumption, optimum allocation model is developed and following two approaches are used : 1) Given the available storage capacity, optimum allocation which minimizes the number of items in the line. 2) Given the available storage capacity, optimum allocation which. maximizes the utilization factor of the line. In a balanced three stage line, the production line efficiency is maximized under both categories when the second in-process storage is larger than the first.

• Communications for Statistical Applications and Methods
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• 제19권6호
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• pp.751-759
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• 2012

This paper proposes an alternative stratified randomized response model based on the model of Singh and Joarder (1997). It is shown numerically that the proposed stratified randomized response model is more efficient than Hong et al. (1994) (under proportional allocation) and Kim and Warde (2004) (under optimum allocation).

• 한국항행학회논문지
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• 제15권3호
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• pp.386-391
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• 2011

인접한 OFDMA 부반송파를 그룹으로 자원을 할당하는 연접할당자원 전송은 IEEE 802.16e/m을 포함한 최근의 다양한 이동통신시스템에서 사용되고 있다. 한 사용자에게 2개 이상의 서로 다른 신호 대 잡음 비를 갖는 연접할당자원이 스케줄러에 의해 할당되고, 해당 사용자는 할당된 채널을 이용하여 복수의 독립된 패킷 스트림을 H-ARQ 전송하는 경우, 재전송 패킷과 신규 전송 패킷을 각각 어떤 채널에 할당하는가에 따라 전송률이 달라진다. 본 논문에서는 상기 문제에 대한 최적 채널 할당 방식을 살펴보고, 최적 할당 방식의 복잡도를 낮출 수 있는 준 최적 할당 방법을 제시하였다. 또한 이에 대한 실험적 성능 분석을 통해 초기전송에 우선하여 우수한 채널을 할당하는 준 최적 방식을 적용할 경우 최적 할당 방식의 복잡도를 대폭 낮추면서도 최적 할당 방식에 근접하는 성능을 얻을 수 있음을 보였다.

• ETRI Journal
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• 제24권4호
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• pp.280-289
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• 2002

In this work, we present a novel approach to the bit allocation problem that aims to minimize overall distortion subject to a bit rate constraint. The optimal solution can be found by the Lagrangian method with dynamic programming. However, the optimal bit allocation for block-based interframe coding is practically unattainable because of the interframe dependency of macroblocks caused by motion compensation. To reduce the computational burden while maintaining a result close to the optimum, i.e., near optimum, we propose an alternative method. First, we present a partitioned form of the bit allocation problem: a "frame-level problem" and "one-frame macroblock-level problems." We show that the solution to this new form is also the solution to the conventional bit allocation problem. Further, we propose a bit allocation algorithm using a "two-phase optimization technique" with an interframe dependency model and a rate-distortion model.

• 한국컴퓨터정보학회논문지
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• 제21권10호
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• pp.37-42
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• 2016

We investigate multi user joint rate scheduling and power allocation problem for a delay sensitive CDMA systems. First, we characterize the existing two user joint rate scheduling and power allocation. We then extend the problem to the case of the multi user systems. In general, there is no simple optimum solution for the multi user scheduling problem. To that end, we propose a sub optimum solution, termed 'virtual user approach'. We show the performance of the virtual user approach to verify the benefit of complexity.

• 한국항해학회지
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• 제5권1호
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• pp.1-23
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• 1981

As far as transportation problems are concerned, the minimization of transportation cost is the most prevailing object. But in some cases, the cargo delivery time is the utter problem rather than the cost. For instance, we may imagine the case that the delivery of the construction materials is delayed behind the schedule and this makes the construction cost increased because of idle time of other materials and man power, in addition to the indemnity. Therefore the allocation of ships, in marine transportation which is now the main route of overseas trade, to the needed area on the required time is to be appropriately performed. However, there are several restrictions for cargo delivery to meet the demand, such as ship's size, number to be employed and cargo handling capacity of the ports, etc. And there are some other factors to be considered, that is, the degree of necessities of commodities, on their kinds, amount, and the time of arrival, etc. This paper deals with the problem of optimum allocation of ships emphasizing the cargo delivery time adopting Linear Programming technique with those cargo delivery restrictions and factors transformed by introducing the multi-speed conception, the conversion of multi-commodity to a single commodity, allowable delivery time, weight penalty number and nominating priority. This paper presents a case of optimum allocation of ships in the light of cargo delivery time for a construction company which has two different construction places and analyzes the result. This study will give a planner a good tool for optimum planning of maring transportation and be used for decision of schemes.

• Advances in Energy Research
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• 제6권1호
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• pp.55-73
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• 2019

The cost incurred by voltage sag effect in power networks has always been of important concern for discussions. Due to the environmental constraints, fossil fuel shortage crisis and low efficiency of conventional power plants, decentralized generation and renewable based DG have become trends in recent decades; because DGs can reduce the voltage sag effect in distribution networks noticeably; therefore, optimum allocation of DGs in order to maximize their effectiveness is highly important in order to maximize their effectiveness. In this paper, a new method is proposed for calculating the cost incurred by voltage sag effect in power networks. Thus, a new objective function is provided that comprehends technical standards as minimization of the cost incurred by voltage sag effect, active power losses and economic criterion as the installation and maintenance costs of DGs. Considering operational constraints of the system, the optimum allocation of DGs is a constrained optimization problem in which Lightning Attachment procedure optimization (LAPO) is used to resolve it and is the optimum number, size and location of DGs are determined in IEEE 33 bus test system and IEEE 34 bus test system. The results show that optimum allocation of DGs not only reduces the cost incurred by voltage sag effect, but also improves the other characteristics of the system.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(2)
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• pp.109-112
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• 2002

This paper presents relationship between the dynamic behavior of an asynchronous linear pipeline (ALP) and the performance of the ALP as buffers are allocated. Then the relationship is used in order to characterize a local optimum situation on the buffer design space of the ALP. Using the characterization we propose an efficient algorithm optimizing buffer allocation on an ALP in order to achieve its average case performance. Without the loss of optimality, our algorithm works in linear time complexity so it achieves fast buffer-configuration optimization. This paper makes two contributions. First, it describes relationship between the performance characteristics of an ALP and a local optimum on the buffer design space of the ALP. Second, it devises a buffer allocation algorithm finding an optimum solution in linear time complexity.