• Journal of the Korea Society for Simulation
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• v.18 no.3
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• pp.35-45
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• 2009

Emergency medical center(EMC) is the place for patients who need medical treatment immediately due to a disease, childbirth, or all sorts of accidents. Currently, most of EMCs use temporary beds because regular EMC beds cannot afford to serve all incoming patients. However, since it decreases the quality of service(QoS) of EMC patients and their guardians and efficiency of the EMC, some improvements are highly required to diminish the usage of temporary beds. The system duration time is one of the typical QoSs. This thesis proposes the information which is critical to make a better decision for cut down the number of temporary beds without sacrificing QoS of patients. The key point is to control the duration time of medical treatments for the consultation and hospitalization process, since it is the major reason of overcrowding in EMC and the usage of temporary beds. In this paper, we proposed an Arena simulation model reflecting real world substantially. Arena is one of the most widely accepted simulation softwares in the world. Using the developed model, we can obtain the optimal EMC operation parameters through simulation experiments. Optquest, included in the Arena, is used to make the developed simulation model collaborate with an optimization model. The results showed one can determine the set of optimal operation parameters decreasing the required number of temporary beds without deteriorating EMC patient's QoS.

• Korean Journal of Construction Engineering and Management
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• v.25 no.5
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• pp.41-54
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• 2024

In this study, we compare and analyze the performance of three inventory management policies for raw material inventory management in a Precast Concrete production plant: Fixed Order Quantity Policy (FOQP), Fixed Order Interval Policy (FOIP), and (s, S) Ordering Policy (sSOP). In order to make more realistic conclusion, we developed and utilized the ARENA simulation model, a performance evaluation tool that considers the variance of raw material demand and supply for the entire production process in a PC production plant using multiple raw materials. For the three policies, reorder point, order quantity, target level, and order interval parameters were initialized by using Economic Order Quantity (EOQ) model and then optimized through OptQuest. As a result of optimization, inventory management costs were reduced by an average of 97.28% compared to the EOQ model that does not consider the variance of demand and supply. After setting three influencing factors, Project Occurrence Cycle (POC), Raw Material Lead-time (RML), and Unit Stock-out Cost (USC), a performance evaluation was conducted for the three policies. As a result of evaluation, the inventory management costs of FOQP and sSOP, which determine order intervals by considering inventory levels by real-time or daily, were 30.6% and 27.9% lower than FOIP with fixed order intervals respectively. In addition, inventory management costs were affected by RML and USC factors excluding POC, but the differences were 2.17% and 2.09% respectively, which were not large due to the optimization of parameters for responding the variance of raw material demand and supply.

• IE interfaces
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• v.23 no.2
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• pp.147-155
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• 2010

Reliability allocation is defined as a problem of determination of the reliability for subsystems and components to achieve target system reliability. The determination of both optimal component reliability and the number of component redundancy allowing mixed components to maximize the system reliability under resource constraints is called reliability-redundancy allocation problem(RAP). The main objective of this study is to suggest a mathematical programming model and a hybrid parallel genetic algorithm(HPGA) for reliability-redundancy allocation problem that decides both optimal component reliability and the number of component redundancy to maximize the system reliability under cost and weight constraints. The global optimal solutions of each example are obtained by using CPLEX 11.1. The component structure, reliability, cost, and weight were computed by using HPGA and compared the results of existing metaheuristic such as Genetic Algoritm(GA), Tabu Search(TS), Ant Colony Optimization(ACO), Immune Algorithm(IA) and also evaluated performance of HPGA. The result of suggested algorithm gives the same or better solutions when compared with existing algorithms, because the suggested algorithm could paratactically evolved by operating several sub-populations and improve solution through swap, 2-opt, and interchange processes. In order to calculate the improvement of reliability for existing studies and suggested algorithm, a maximum possible improvement(MPI) was applied in this study.

• Bulletin of the Korean Chemical Society
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• v.35 no.3
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• pp.908-912
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• 2014

Microgratings whose diffracted field at a fixed angle generate IR spectra of $SF_6$ or $NH_3$ were fabricated by MEMS techniques for the purpose of IR correlation spectroscopy. Each micrograting was composed of 1441 reflecting lines in the area of $19.2{\times}19.2mm^2$. The depth profile of the line elements was determined with a gradient searching method that was described in our previous publication (J. Mod. Opt. 2013, 60, 324-330), and was discretized into 16 levels between 0 and $6.90{\mu}m$. The diffraction field from a given depth profile was calculated with Fraunhofer equation. The fabricated microgratings showed errors in the depth and the width within acceptable ranges. As the result, the diffracted IR spectrum of each micrograting matched well with its target reference spectrum within spectral resolution of our optical setup.

• Human Ecology Research
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• v.53 no.2
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• pp.195-208
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• 2015

This study explored general marriage migration for 180 unmarried Vietnamese immigrant women and identified differences in recognition after the choice of marriage. The methods used were frequency analysis, kai verification, and independent t verification were conducted. The findings were as follows. First, unmarried Vietnamese women showed a receptive attitude towards marriage migration with the less-educated group more likely to opt for marriage migration. Economic benefit expectations topped other factors in regards to the image of marriage migrant women and motivation. Dual national identity benefits were also indicated. Second, the perception of external and illusionary images of the spouses of marriage migrant women was low; however, the perception of good occupations and gender equality was high. A vague expectancy of marriage was also found. The perception was high that children from multi-cultural families would be global bilingual talents and adjust to school; however, the perception of social discrimination or prejudice was low. The perception of social discrimination was low concerning the perception of social integration towards marriage migrant women; however, the perception of identities, cultural differences and employment was present. By contrast, the group opting for marriage migration showed a significantly low perception of social discrimination and difficulty in employment. The suggested measures are to regulate and maintain forms of marriage type, reinforce prior training systems for Vietnamese immigrant women (and spouses), enhance multicultural recognition, and supplement multicultural policies.

• The KIPS Transactions:PartC
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• v.12C no.6 s.102
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• pp.793-798
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• 2005

We focus on the RP (Rendezvous Point) system model in the multicast network based on BcN (Broadband Convergence Network) integrating broadcasting, telecommunication and Internet with one. Based on the condition multiple queues with different service and single server, when the arrivals tome in group with the site of the group geometrically distributed, we define the relationship between incoming arrival rate and corresponding buffer size. We also investigate the Profit according to both Service Provider and Network Operator Then we make a decision whether a new service request is accepted or not based on given interning rate range.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.117.2-117.2
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• 2011

We probe 12CO J=2-1 and 13CO J=1-0 properties of a Virgo disk galaxy, NGC 4402 which is located near the cluster center. Our goal is to study the impact of intra cluster medium (ICM) on the molecular gas of a galaxy in the cluster environment. It has been believed that cluster galaxies are deficient in atomic hydrogen gas (HI gas) compared to their field counterparts and now there is much evidence that low density ISM can be easily removed by ram pressure caused by ICM wind. Meanwhile, no significant molecular gas deficiency of the cluster galaxy population has been found yet they show overall lower star formation rate than galaxies in the field, and it is still controversy whether dense ISM can be also stripped by the ICM wind or not. NGC 4402 with truncated HI disk($D_{HI}/D_{opt}$ ~ 0.75 and only 36%of HI gas compare to field galaxies of a similar size) and a disturbed gas morphology, appears to have strong ongoing ram pressure. Using high resolution 12 and 13CO data of NGC 4402 from a Sub Millimeter Array (SMA), we probe the molecular gas properties under strong ICM pressure. We discuss how its star formation activity and hence the global color of NGC4402 would be changed in the future.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.2
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• pp.48-55
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• 2010

Reliability has been considered as a one of the major design measures in various industrial and military systems. The main objective is to suggest a mathematical programming model and a hybrid parallel genetic algorithm(HPGA) for the problem that determines the optimal component reliability to maximize the system reliability under cost constraint in this study. Reliability optimization problem has been known as a NP-hard problem and normally formulated as a mixed binary integer programming model. Component structure, reliability, and cost were computed by using HPGA and compared with the results of existing meta-heuristic such as Ant Colony Optimization(ACO), Simulated Annealing(SA), Tabu Search(TS) and Reoptimization Procedure. The global optimal solutions of each problem are obtained by using CPLEX 11.1. The results of suggested algorithm give the same or better solutions than existing algorithms, because the suggested algorithm could paratactically evolved by operating several sub-populations and improving solution through swap and 2-opt processes.

• Journal of English Language & Literature
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• v.64 no.3
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• pp.383-401
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• 2018

Wordsworth is a poet who thought seriously about problems of human's relation to the world as perceiving subjects. What he calls "the life of things" illustrates the enabling power of things and their vitalities at play in excess of human elements. Drawing on this, he provides insights into vital materialities that act upon, and are acted upon by, the collaborative circulation between human and nonhuman agency. This paper aims to reinvigorate the debate about Wordsworth's ethics of things in terms of such critical notions as things, objects, agency, and nonhumans in an attempt to explain what he envisions as new environmental realities built upon nonhierarchical, collaborative relationships between all participants. From the vantage point of things, we see clearly what has been neglected in the New Historicist critical method. It holds fast to the conceit that humans are entitled to have sole agential legitimacy, disregarding the vibrancy of things. They opt for the objectified matter or the (re)presented state of things. But in terms of Wordsworth's life of things, all participants have equal amounts of agency regardless of their forms and for that reason humans are expected to respect other things' sovereignty. Through encounters with things, things in their thingness show up for us, only to reveal the ineradicable rupture between themselves and their objectified forms.

• Acta Via Serica
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• v.7 no.1
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• pp.131-148
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• 2022

While much has been written about Imperial Japan's encounter with geopolitics and developing ideas about Geography as a political and cultural discipline, little if anything has been written about relational and research Geographies between Japan and Silk Roads both ancient and modern. Memories of the ancient Silk Road were revivified in the late 19^th century in tandem with the Great Game of European nations, as Japan modernized and sought new places and influence globally following the Meiji restoration. Imperial Japan thus sought to conquer and co-opt spaces imagined to be part of or influenced by the ancient Silk Road and any modern manifestation of it. This paper explores a particular process in that co-option and appropriation, research collaboration between institutions of the Empire. In particular it considers the exploration of Mengjiang/Inner Mongolia after its conquest in 1939/1940, by a collaborative team of Korean and Japanese Geographers, led by Professor Tada Fumio. This paper considers the making knowable of spaces imagined to be on the ancient Silk Road in the Imperial period, and the projecting of the imperatives of the Empire back into Silk Road history, at the same time as such territory was being made anew. This paper also casts new light on the relational and collaborative processes of academic exchange, specifically in the field of Geography, between Korean and Japanese academics during the Korean colonial period.