• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.47
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• pp.1-10
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• 1998

Testing high reliability devices under nomal operating condition is difficult, because the devices are not likely to fail in the relatively short time available for tests. For most applications it is necessary to accelerate the causes of failure by increasing a stress above its nomal value. Previous accelerated life test(ALT) plans have shown how to find optimum allocation, lowest stress and sample size subject to minimizing the variance of mean life estimator. In these ALT plans, the highest acceptable test-stress was assumed to be specified in advance by the experimenter but there is no guidance for selecting it. This assumption is, however, inappropriate for many applications. Testing devices at too-high stress levels can invalidate the extrapolation model, or introduce failure mechanisms that are not anticipated under nomal operating conditions. In this paper, we propose new 4:2:1 compromise plans using Min-Max method to minimize this risk and present minimized test-stress levels(max, middle, min), and find sample allocation based on Min-Max 4:2:1 compromise plans. In result, we compare previous 4:2:1 compromise plans specified maximum test-stress with Min-Max 4:2:1 compromise plans minimized maximum test-stress.

• Journal of the Korea Society of Computer and Information
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• v.11 no.2 s.40
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• pp.1-6
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• 2006

In this paper, a RTL binding technique and low power technology mapping consider CPLD is proposed. Allocation processing selected module consider the module calculation after scheduling process for circuit by HDL. Select CPLD for constrain after allocation. A Boolean equation is partitioned for CLB by allocated modules. The proposed binding algorithm is description using optimum CLB within a CPLD consider low power. The proposed algorithm is examined by using 16 bit FIR filter. In the case that applicate the algorithm, the experiments results show reduction in the power consumption by 43% comparing with that of non application algorithm.

• Journal of Communications and Networks
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• v.9 no.2
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• pp.112-117
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• 2007

In this paper, we focus on the total transmission power minimization problem for downlink beamforming multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems while ensuring each user's QoS requirement. Although the linear integer programming (LIP) solution we formulate provides the performance upper bound of the margin adaptive (MA) optimization problem, it is hard to be implemented in practice due to its high computational complexity. By regarding each user's equivalent channel gain as approximate independent values and using iterative descent method, we present a heuristic MA resource allocation algorithm. Simulation results show that the proposed algorithm efficiently converges to the local optimum, which is very close to the performance of the optimal LIP solution. Compared with existing space division multiple access (SDMA) OFDM systems with or without adaptive resource allocation, the proposed algorithm achieves significant performance improvement by exploiting the frequency diversity and multi-user diversity in downlink multiple-input single-output (MISO) OFDM systems.

• International conference on construction engineering and project management
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• 2007.03a
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• pp.530-539
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• 2007

Many construction projects such as highways, pipelines, tunnels, and high-rise buildings typically contain repetitive activities. Research has shown that the Critical Path Method (CPM) is not efficient in scheduling linear construction projects that involve repetitive tasks. Linear Scheduling Method (LSM) is one of the techniques that have been developed since 1960s to handle projects with repetitive characteristics. Although LSM has been regarded as a technique that provides significant advantages over CPM in linear construction projects, it has been mainly viewed as a graphical complement to the CPM. Studies of scheduling linear construction projects with resource consideration are rare, especially with multiple resource constraints. The objective of this proposed research is to explore a resource assignment mechanism, which assigns multiple critical resources to all activities to minimize the project duration while satisfying the activities precedence relationship and resource limitations. Resources assigned to an activity are allowed to vary within a range at different stations, which is a combinatorial optimization problem in nature. A heuristic multiple resource allocation algorithm is explored to obtain a feasible initial solution. The Simulated Annealing search algorithm is then utilized to improve the initial solution for obtaining near-optimum solutions. A housing example is studied to demonstrate the resource assignment mechanism.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.1
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• pp.15-22
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• 2006

In OFDMA system, even if the number of allocated sub-channel in mobile station varies from one to the whole sub-channel as in base station, while because of mobile station's transmit power is lower than that of base station, therefore full loading range(FLR) constraint occurs where whole sub-channel can be used and the conventional open-loop power control scheme can not be used beyond FLR. We propose a new scheme that limits the maximum sub-channel allocation number and uses power concentration gain(PCG) depending on location of mobile station, which is based on ranging in OFDMA system. Simulation results show that the proposed scheme provides solutions for optimum utilization of radio resource depending on the location of mobile station and enables open-loop power control beyond FLR without extra hardware complexity.

• Journal of the military operations research society of Korea
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• v.36 no.1
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• pp.15-27
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• 2010

Fire sequencing problem is to find a sequence of firing on the targets. The latest, because the korea artillery force is inferior in number as compared with north korea force. It is an important question to give a fatal damage to the enemy force by using prompt and accurate fire in order to overcome the lack of artillery force. Minimizing the fire finishing time will secure the adapt ability in tactical operation. In this paper, we developed a mathematical model to do allocation the fire on the targets to decrease to total fire operation time. In order to work out the fire sequencing problem, MIP is developed and the optimum solution is obtained by using ILOG OPL. If this analytical model is applied to the field artillery unit, it will improve the artillery fire force enhancement.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.9A
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• pp.729-736
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• 2005

In this paper, we introduce a new approach for the design of uplink sub-channel allocation and power control in the High-speed Portable Internet system that is based on OmMAnDD scheme. In OFDMA system, because the number of allocated sub-channel in mobile station varies from one to the whole sub-channel as in base station while mobile station's transmit power is lower than that of base station, full loading range(FLR) constraint occurs where whole sub-channel can be used and the conventional open-loop power control scheme can not be used beyond FLR. We propose a new scheme that limits the maximum sub-channel allocation number and uses power concentration gain(PCG) depending on location of mobile station, which is based on ranging in OfDMA system. Simulation results show that the proposed scheme extends the uplink coverage to the entire cell service coverage area, provides solutions for optimum utilization of radio resource and enables open-loop power control beyond FLR without extra hardware complexity.

• The Korean Journal of Applied Statistics
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• v.26 no.2
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• pp.209-222
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• 2013

We apply stratified cluster sampling to a replicated systematic unrelated question model for a large scale survey in which the population is comprised of several strata developed by several clusters and with sensitive parameters. We first present a replicated systematic unrelated question model using an unrelated question model to procure sensitive information from the population of clusters and then develop a suggested model to an unrelated question by a stratified cluster replicated systematic sampling that can be used in large population of strata. We cover the proportional and optimum allocation for the suggested model. Finally, we compare and analyze the efficiency of the suggested model with the replicated systematic unrelated question model.

• Journal of Korean Society of Rural Planning
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• v.4 no.1
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• pp.98-107
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• 1998

For efficient development of rural facilities, choice of their optimum locations would be an important issue, however, existing research works concentrated much more an allocation policy of urban industrial complex and public facilities than rural ones. In this study, because agricultural-cum-industrial complex has been the most widely developed representative one of rural facilities, it was selected as a case study facility. As a pre-study to system development, existing governmental location-decision system was checked and interviewing survey carried out to find out on-spot problems. And, being based on literature review and survey analysis results, 4-step optimum locational decision model was developed , formulation of locational goal system, ranking tabulation on components, determination of significance values of components, calculation of component scores. Finally, through the case study works on 3 sites, system applicability was checked, Considering together the simplicity problem of existing guidelines and the interviewing survey results favoring the diversified viewpoints, it would be necessary to develop multifaceted support system for locational decision making. 3-tier classification steps from the higher, middle to lower one were used and their underpinning viewpoints were sorted as on regional development, entrepreneurship, spatial rationality, from which a tentative locational goal system was formulated. Through the expert group checking, final locational goal system was determined having 3 of the higher classification items, 7 of the middle ones, 23 of the lower ogles. For ranking tabulation, 3 types of ranking criteria were arranged which were based on statistical analysis using mean and standard deviation(Type I ), its existence or not 1 good or not(Type E ), and the others(Type E ). From the significance evaluation results, regional development and entrepreneurship aspects were valued much higher than spatial rationality aspect. And, in the middle step, items as spread effects of regional economy, accessibility and social potentialities were highly valued while infrastructural development level and natural condition being low. The application results of the system to 3 case study total. However, the detailed ones differed among study the influencing effects on regional economy, and contrast greater the infrastructural development level. Conclusively, final evaluation values well represented the characteristics of each area. If this system be complemented and applied comprehensively by the successive studies, it would be developed to a general model of locational decision supporting system for rural facilities.

• Food Science of Animal Resources
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• v.38 no.2
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• pp.240-250
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• 2018

This study was undertaken to find the optimum soy-peptone, glucose, yeast extract, and magnesium sulfate amounts for the maximum growth of Lactobacillus plantarum JNU 2116 and to assess the effects of these medium factors through the use of response surface methodology. A central composite design was used as the experimental design for the allocation of treatment combinations. In the analysis of the experiment, due to a significant lack of fit of the second-order polynomial regression model that was used at first, cubic terms were added to the model, and then two-way interaction terms were deleted from the model since they were found to be all statistically insignificant. A relative comparison among the four factors showed that the growth of L. plantarum JNU 2116 was affected strongly by yeast extract, moderately by glucose and peptone, and slightly by magnesium sulfate. The estimated optimum amounts of the medium factors for the growth of L. plantarum JNU 2116 are as follows: soy-peptone 0.213%, glucose 1.232%, yeast extract 1.97%, and magnesium sulfate 0.08%. These results may contribute to the production of L. plantarum L67 as a starter culture that may have potential application in yogurt and fermented meat products.