• Journal of Korean Institute of Industrial Engineers
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• v.38 no.4
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• pp.262-275
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• 2012

This paper develops a multistage scheduling algorithm for the module operation of the LCD(Liquid Crystal Display) production systems and tests the efficiency of the proposed algorithm. The module operation is a multistage form composed of multiple sub operations of processes, and each stage is consists of multiple lines with the same kinds of machines. This paper presents a mathematical modeling reflecting the constraints of the LCD module operation and develops a multistage scheduling algorithm based on tabu search metaheuristic approach. For this purpose, an production order is assigned to a line of the sub operations and a sequence of the assigned order is rearranged to draw an efficient schedule. Simulation experiments test performance measures and show the efficiency of the proposed algorithm.

• Korean System Dynamics Review
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• v.12 no.1
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• pp.89-114
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• 2011

With steady increase in the demand for door-to-door delivery services, courier service providers are facing a constant pressure to reduce delivery price in order to secure quantity order and to improve the efficiency and reliability for customer service. The objective of this research is to explain the structure of the door-to-door delivery including door-to-door delivery service demand, sorting capacity in the hub-terminal, and the system performance measures such as service reliability networks using causal loop diagram(CLD). Based on causal relation, this research describes a comprehensive approach to examine how capacity reliability contributes to the renewal of the firm's competences through its reciprocal relationship with travel time reliability and connectivity reliability. Also, this research suggests the policy alternatives to improve effectiveness and efficiency of door-to-door delivery network in response to increase customer satisfaction and profit maximization of the courier service providers: operational, tactical, and strategic levels.

• International Journal of Computer Science & Network Security
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• v.21 no.11
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• pp.312-320
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• 2021

Increase in computational cost and exhaustive search can lead to more complexity and computational energy. Thus, there is need for effective and efficient scheme to reduce the complexity to achieve optimal energy utilization. This will improve the energy efficiency and enhance the proficiency in terms of the resources needed to achieve convergence. This paper primarily focuses on the development of hybrid swarm intelligence scheme for reducing the computational complexity in binary optimization. In order to reduce the complexity, both artificial bee colony (ABC) and particle swarm optimization (PSO) have been employed to effectively minimize the exhaustive search and increase convergence. First, a new approach using ABC and PSO has been proposed and developed to solve the binary optimization problem. Second, the scout for good quality food sources is accomplished through the deployment of PSO in order to optimally search and explore the best source. Extensive experimental simulations conducted have demonstrate that the proposed scheme outperforms the ABC approaches for reducing complexity and energy consumption in terms of convergence, search and error minimization performance measures.

• Journal of the Korea Convergence Society
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• v.12 no.2
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• pp.259-269
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• 2021

Many researchers have discussed on a policy establishment to revitalize a regional industry of a domestic ecosystem. However, it is rare to consider activation measures and priorities that are appropriate for local characteristics. Therefore, this study conducted a qualitative study to gather and analyze the views of expert groups in order to derive measures to revitalize the automobile industry in Gwangju. We examined the current status of the automobile industry in Gwangju based on a literature survey and in-depth interviews and what kind of crisis there is. We then derive strategic candidates for activation measures to address this. In addition, the relative importance and priorities of the methods derived using AHP techniques were identified. This leads to five strategies on which methods should be applied first. This will be used as the basis for future strategy development.

• Korean Journal of Construction Engineering and Management
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• v.16 no.1
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• pp.92-100
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• 2015

This study proposes measures to improve management performance of construction projects by re-designing the organizational structures of the Regional Construction Management Administrations of the Ministry of Land, Infrastructure and Transport. The re-designing measures are derived based on the three measures which were established by analyses on status of the Regional Construction Management Administrations, requirements from the current organizational structure, and domestic/overseas examples; the measures are: 1) organizational integration and scope expansion, 2) structural re-organization according to construction projects, and 3) building a knowledge management structure. In order to realize the re-designing measures, sixteen tasks are derived; a milestone is established according to importance, feasibility and lead-lag relationships of these tasks. If these tasks are to be carried out successfully, the management performance of the Regional Construction Management Administrations of the Ministry of Land, Infrastructure and Transport will be expected to improve. Ultimately, the Regional Construction Management Administrations can reduce cost and improve the quality of public service by outsourcing the non-core competence tasks and by concentrating on the construction management for the new infrastructure projects.

• Journal of Korean Institute of Industrial Engineers
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• v.29 no.2
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• pp.135-144
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• 2003

Traffic performance in a microcellular system is much more affected by cell dwell time and channel holding time in each cell. Cell dwell time of a call is characterized by its mobility pattern, i.e., stochastic changes of moving speed and direction. Cell dwell time provides important information for other analyses on traffic performance such as channel holding time, handover rate, and the average number of handovers per call. In the next generation mobile communication system, the cell size is expected to be much smaller than that of current one to accommodate the increase of user demand and to achieve high bandwidth utilization. As the cell size gets small, traffic performance is much more affected by variable mobility of users, especially by that of pedestrians. In previous work, analytical models are based on simple probability models. They provide sufficient accuracy in a simple second-generation cellular system. However, the role of them is becoming invalid in a picocellular environment where there are rapid change of network traffic conditions and highly random mobility of pedestrians. Unlike in previous work, we propose an improved probability model evolved from so-called Random walk model in order to mathematically formulate variable mobility of pedestrians and analyze the traffic performance. With our model, we can figure out variable characteristics of pedestrian mobility with stochastic correlation. The above-mentioned traffic performance measures are analyzed using our model.

• KIPS Transactions on Software and Data Engineering
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• v.6 no.11
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• pp.507-520
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• 2017

The set-based similar sequence matching method measures similarity not for an individual data item but for a set grouping multiple data items. In the method, the similarity of two sets is represented as the size of intersection between them. However, there is a critical performances issue for the method in twofold: 1) calculating intersection size is a time consuming process, and 2) the number of set pairs that should be calculated the intersection size is quite large. In this paper, we propose an index-based search method for improving performance of set-based similar sequence matching in order to solve these performance issues. Our method consists of two parts. In the first part, we convert the set similarity problem into the intersection size comparison problem, and then, provide an index structure that accelerates the intersection size calculation. Second, we propose an efficient set-based similar sequence matching method which exploits the proposed index structure. Through experiments, we show that the proposed method reduces the execution time by 30 to 50 times then the existing methods. We also show that the proposed method has scalability since the performance gap becomes larger as the number of data sequences increases.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.11 no.3
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• pp.165-170
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• 2011

Due to advances in hardware performance, user-friendly interfaces are becoming one of the major concerns in information systems. Linguistic conversation is a very natural way of human communications. Fuzzy techniques have been employed to liaison the discrepancy between the qualitative linguistic terms and quantitative computerized data. This paper deals with linguistic queries using clustering results on data sets, which are intended to retrieve the close clusters or distant clusters from the clustering results. In order to support such queries, a fuzzy technique-based method is proposed. The method introduces distance membership functions, namely, close and distant membership functions which transform the metric distance between two objects into the degree of closeness or farness, respectively. In order to measure the degree of closeness or farness between two clusters, both cluster closeness measure and cluster farness measure which incorporate distance membership function and cluster memberships are considered. For the flexibility of clustering, fuzzy clusters are assumed to be formed. This allows us to linguistically query close or distant clusters by constructing fuzzy relation based on the measures.

• The Journal of the Acoustical Society of Korea
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• v.35 no.1
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• pp.49-54
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• 2016

In this paper, we propose a vocal separation method using weighted ${\beta}$-order minimum mean wquare error estimation (WbE) based on kernel back-fitting algorithm. In spoken speech enhancement, it is well-known that the WbE outperforms the existing Bayesian estimators such as the minimum mean square error (MMSE) of the short-time spectral amplitude (STSA) and the MMSE of the logarithm of the STSA (LSA), in terms of both objective and subjective measures. In the proposed method, WbE is applied to a basic iterative kernel back-fitting algorithm for improving the vocal separation performance from monaural music signal. The experimental results show that the proposed method achieves better separation performance than other existing methods.

• Journal of the Korea Safety Management & Science
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• v.13 no.1
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• pp.1-9
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• 2011

It is a significant issue for several country including Korea, where the natural and the weather conditions are severe, to keep the safety against disasters which occur frequently every year, especially in urban region crowded with population. In order to implement suitable and effective measures against various disasters in such area, development of method for evaluation of disaster prevention performance based on various disaster risks and effective disaster damage mitigation technologies is independable. In this paper, methods for hazard evaluation, vulnerability evaluation and loss evaluation, and damage technologies are proposed targetting man-made disaster and natural one like flood, earthquake and tsunami and so on. The method proposed in this paper is based on the research of USA and Japan for man-made disaster and natural disaster. The proposed method will be developed in detail in four years during research period funded by government.