• Journal of Korean Institute of Industrial Engineers
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• v.20 no.4
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• pp.85-97
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• 1994

An interactive and iterative control panel layout method based on the constraint satisfaction problem (CSP) technique was developed to generate an ergonomically sound panel design. This control panel layout method attempts to incorporate a variety of relevant ergonomic principles and design constraints, and generate an optimal or, at least, a "satisfactory" solution through an efficient search algorithm. The problem of seeking an ergonomically sound panel design should be viewed as a multi-criteria design problem and most of the design objectives should be understood as constraints. Hence, a CSP technique was employed in this study for dealing with the multi-constraints layout problem. The efficient search algorithm using "preprocess" and "look_ahead" procedures was developed to handle vast amount of computation. In order to apply the CSP technique to the panel layout procedure, the ergonomic principles such as spatial compatibility, frequency-of-use, importance, functional grouping, and sequence-of-use were formalized as CSP terms. The effectiveness of the proposed panel layout method was evaluated by example problems and the results clearly showed that the generated layouts properly considered various ergonomic design principles.

• Journal of the Korean housing association
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• v.16 no.6
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• pp.111-120
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• 2005

To design common facilities that support residents' leisure activities is one of the comtemporary issues in Korea. People became interested in the leisure facilities in near-home environments. This trend encouraged this research study. The objectives of this study are: to analyze the current status and characteristics of leisure facilities in apartment communities, to examine the correlations among leisure facilities, and to suggest design considerations for Korean multi-family housing communities. Subject communities are located in the five metropolitan areas in the United States. The 460 apartment communities were randomly selected after a thorough review of a website for apartment finders. Among them, the 126 communities were selected for the analysis. Primary findings are as follows: (1) A total of 30 facilities were identified as the creational facilities in apartment properties. (2) Some leisure facilities were correlated with the other facilities, based on the Pearson's correlation analysis.(3) In addition to the facilities, some apartment communities provide leisure programs for their residents. These results suggest that architectural interventions and maintenance services as well should be considered in order to lead diverse leisure activities for residents.

• Journal of Environmental Health Sciences
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• v.42 no.6
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• pp.409-418
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• 2016

Objectives: The purpose of this study was to characterize penicillin G resistant bacteria in surface water from pharmaceutical complex effluent. Methods: Surface water was sampled from pharmaceutical complex effluent in Gyeonggi-do Province, Korea in March 2015. Water samples were plated in triplicate on tryptic soy agar plates with 32 mg/L of penicillin G. Penicillin G resistant bacteria were selected from the effluent and subjected to 16S rRNA analysis for the penicillin G resistant species determination. Identified resistant strains were tested for resistance to various antibiotics. Results: Penicillin G resistant bacteria were present at 8.0% in terms of culturable heterotrophic bacteria. Identified penicillin G resistant bacteria exhibited resistance to more than nine of the antibiotics studied. These resistant bacteria are gram negative and are closely related to pathogenic species. Conclusion: Multi-antibiotic resistant bacteria in the surface water of pharmaceutical complex effluent suggest the need for disinfection and advanced oxidation processed for pharmaceutical effluent.

• Korean Journal of Health Education and Promotion
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• v.28 no.4
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• pp.1-14
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• 2011

Objectives: The aim of the present study is to elucidate the relationship of community capacity to health in a metropolitan area in Korea. To do so, a multi-level model to verify the contextual effects of community capacity is presented. Methods: The study materials are the "The 4th Seoul Citizens Health Indicators Surveys" on 404 dong in Seoul. The community capacity indicators were developed in two strata: individual-level indicators with community identity domain; and community-level indicators with participation in community organizations, number of non-profit organizations, degree of organizing of community-based organizations, and volunteer activities. Results: Higher unhealthy probability occurs among those with lower community capacity at the community level, lower individual income, and lower community satisfaction at the individual level. It contributed to explaining self-rated health status and showed that there were contextual effects of the community going beyond the compositional effects of the individual. Conclusions: In the process of building community capacity, a community autonomously finds pending issues and solves related problems, and in so doing, raises the social quality and establishes the conditions for health promotion. Thus, the significance of neighborhood needs to be discovered and created in a new way through the development of community capacity.

• Journal of Families and Better Life
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• v.20 no.2
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• pp.83-95
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• 2002

The objectives of this study were 1) to analyze the attitudes about Elderly Assisted Living(EAL), 2) to consider the policy implications for elderly communal housing according to socio-economic status(income, occupation and education). The survey was undertaken from August to September, 2000 in Seoul and Kyunggi-Do(Ilsan, Bundang). The data were analyzed by SPSS Window program. The major findings were as follows: Most of the respondents prefered to live in EAL(over 56%), under 10 units and desired to be serviced(housework.leisure medical program.meal service). The upper class respondents preferred high-rise apartment style inner city or suburban and prefered paid services in EAL. They would willingly to pay over 800,000 won for living expenses and more than 200 million won for buying their own EAL. The middle class respondents prefered 5 stories multi-family house style with common facilities as a number. And they prefered to common facilities opening to public if the quality of facilities were better. The low class respondents prefered 5 stories multi-family house style and prefered to live within 30 minutes apart from their families and friends. They would pay under 300,000~600,000won for monthly living expenses and under 100 million won for their own EAL.

• Journal of Electrical Engineering and Technology
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• v.10 no.2
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• pp.474-486
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• 2015

This paper proposes a multi-objective optimal placement method of Phasor Measurement Units (PMUs) in large electric transmission systems. It is proposed for minimizing the number of PMUs for complete system observability and maximizing measurement redundancy of the buses, simultaneously. The measurement redundancy of the bus indicates that number of times a bus is able to monitor more than once by PMUs set. A high level of measurement redundancy can maximize the system observability and it is required for a reliable power system state estimation. Therefore, simultaneous optimizations of the two conflicting objectives are performed using a binary coded firefly algorithm. The complete observability of the power system is first prepared and then, single line loss contingency condition is added to the main model. The practical measurement limitation of PMUs is also considered. The efficiency of the proposed method is validated on IEEE 14, 30, 57 and 118 bus test systems and a real and large- scale Polish 2383 bus system. The valuable approach of firefly algorithm is demonstrated in finding the optimal number of PMUs and their locations by comparing its performance with earlier works.

• Earthquakes and Structures
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• v.10 no.5
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• pp.1067-1087
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• 2016

In this paper, a decoupled proportional-integral-derivative (PID) control approach for seismic control of smart structures is presented. First, the state space equation of a structure is transformed into modal coordinates and parameters of the modal PID control are separately designed in a reduced modal space. Then, the feedback gain matrix of the controller is obtained based on the contribution of modal responses to the structural responses. The performance of the controller is investigated to adjust control force of piezoelectric friction dampers (PFDs) in a benchmark base isolated building. In order to tune the modal feedback gain of the controller, a suitable trade-off among the conflicting objectives, i.e., the reduction of maximum modal base displacement and the maximum modal floor acceleration of the smart base isolated structure, as well as the maximum modal control force, is created using a multi-objective cuckoo search (MOCS) algorithm. In terms of reduction of maximum base displacement and story acceleration, numerical simulations show that the proposed method performs better than other reported controllers in the literature. Moreover, simulation results show that the PFDs are able to efficiently dissipate the input excitation energy and reduce the damage energy of the structure. Overall, the proposed control strategy provides a simple strategy to tune the control forces and reduces the number of sensors of the control system to the number of controlled stories.

• Environmental Analysis Health and Toxicology
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• v.30
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• pp.1.1-1.8
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• 2015

Objectives In this study, the effect of tube length and outer diameter (OD) size of hydroxylated-multi walled carbon nanotubes (OH-MWCNTs) on their uptake and toxicity was investigated in the nematode Caenorhabditis elegans using a functional mutant analysis. Methods The physicochemical properties of three different OH-MWCNTs were characterized. Uptake and toxicity were subsequently investigated on C. elegans exposed to MWCNTs with different ODs and tube lengths. Results The results of mutant analysis suggest that ingestion is the main route of MWCNTs uptake. We found that OH-MWCNTs with smaller ODs were more toxic than those with larger ODs, and OH-MWCNTs with shorter tube lengths were more toxic than longer counterparts to C. elegans. Conclusions Overall the results suggest the aspect ratio affects the toxicity of MWCNTs in C. elegans. Further thorough study on the relationship between physicochemical properties and toxicity needs to be conducted for more comprehensive understanding of the uptake and toxicity of MWCNTs.

• Structural Engineering and Mechanics
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• v.25 no.2
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• pp.239-268
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• 2007

This paper deals with optimal stacking sequence design of laminate composite structures. The stacking sequence optimisation of laminate composites is formulated as a combinatorial problem and is solved using Simulated Annealing (SA), an algorithm devised based on inspiration of physical process of annealing of solids. The combinatorial constraints are handled using a correction strategy. The SA algorithm is strengthened by embedding Tabu search in order to prevent recycling of recently visited solutions and the resulting algorithm is referred to as tabu embedded simulated Annealing (TSA) algorithm. Computational performance of the proposed TSA algorithm is enhanced through cache-fetch implementation. Numerical experiments have been conducted by considering rectangular composite panels and composite cylindrical shell with different ply numbers and orientations. Numerical studies indicate that the TSA algorithm is quite effective in providing practical designs for lay-up sequence optimisation of laminate composites. The effect of various neighbourhood search algorithms on the convergence characteristics of TSA algorithm is investigated. The sensitiveness of the proposed optimisation algorithm for various parameter settings in simulated annealing is explored through parametric studies. Later, the TSA algorithm is employed for multi-criteria optimisation of hybrid composite cylinders for simultaneously optimising cost as well as weight with constraint on buckling load. The two objectives are initially considered individually and later collectively to solve as a multi-criteria optimisation problem. Finally, the computational efficiency of the TSA based stacking sequence optimisation algorithm has been compared with the genetic algorithm and found to be superior in performance.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.3
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• pp.40-48
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• 2009

In this article, scheduling of a casting sequence is studied in a casting foundry which must deliver products according to the Just-in-time(JIT) production policy of a customer. When a foundry manufactures a variety of casts with an identical alloy simultaneously, it frequently faces the task of production scheduling. An optimal casting schedule should be emphasized in order to maximize the production rate and raw material efficiency under the constraints of limited resources; melting furnaces and operation time for a casting machine. To solve this practical problem-fulfilling the objectives of casting the assigned mixed orders for the highest raw material efficiency in a way specified by the customer's JIT schedule, we implement simple integer programming. A simulation to solve a real production problem in a typical casting plant proves that the proposed method provides a feasible solution with a high accuracy for a complex, multi-variable and multi-constraint optimization problem. Employing this simple methodology, a casting foundry having an automated casting machine can produce a mixed order of casts with a maximum furnace utilization within the due date, and provide them according to their customer's JIT inventory policy.