• Journal of the Korea Society for Simulation
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• v.23 no.4
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• pp.229-235
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• 2014

Improving the time and cost efficiency of production systems is one of the important means of building competitive advantage and staying profitable in the ever increasing competitive business environment. Among others, CONWIP (constant work-in-process) and DBR (drum-buffer-rope) methods are widely used in improving production process efficiency. In this study, we have developed simulation models for a real button factory production system. We have tried to improve the efficiency of the production process by implementing these two approaches to our model. According to our results, both CONWIP and DBR production approaches were found to have equivalently better results in reducing the waiting time of the bottleneck process. By applying either of the two production systems, efficiency of the real production process can be significantly improved as the simulated model results demonstrate.

• Structural Engineering and Mechanics
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• v.64 no.2
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• pp.195-204
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• 2017

Analytical and experimental studies of the innovative pipe in pipe damper have been recently investigated by the authors. In this paper, by adding lead or zinc infill or slit diaphragm inside the inner pipe, it is tried to increase the equivalent viscous damping ratio improving the cyclic performance of the recently proposed multi-level control system. The damper consists of three main parts including the outer pipe, inner pipe and added complementary damping part. At first plastic deformations of the external pipe, then the internal pipe and particularly the added core and friction between them make the excellent multi-level damper act as an improved energy dissipation system. Several kinds of added lead or zinc infill and also different shapes of slit diaphragms are modeled inside the inner pipe and their effectiveness on hysteresis curves are investigated with nonlinear static analyses using finite element method by ABAQUS software. Results show that adding lead infill has no major effect on the damper stiffness while zinc infill and slit diaphragm increase damper stiffness sharply up to more than 10 times depending on the plate thickness and pipe diameter. Besides, metal infill increases the viscous damping ratio of dual damper ranging 6-9%. In addition, obtained hysteresis curves show that the multi-level control system as expected can reliably dissipate energy in different imposed energy levels.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.1
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• pp.29-35
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• 2020

Car inspection systems are regularly carried out by the state to ensure the safety and emission status of cars, thereby improving the safety and quality of life by reducing fine dust and greenhouse gases that are the main culprits of vehicle defects and air pollution. These automobile inspections are largely divided into either regular or comprehensive inspections. This study analyzed the smoke measuring probes used in the lug - down 3 mode. In the previously issued paper "Improvement of Soot Probe Efficiency for Automotive Emission Measurement," an improved smoke measurement probe(B) improved on the problems that arise from the current smoke measurement probe (A). In this study, a technique that can improve the probe's inhalation efficiency over the improved (B) probes was applied to probes (C). Probe (C) involves a structure designed close to the center of the circumference of the exhaust pipe, and the suction efficiency was improved by adding a variable center unit.

• Journal of Power Electronics
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• v.12 no.3
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• pp.418-428
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• 2012

It is very important to improve the overall efficiency of systems with a source of power that has low-voltage high-current terminal characteristics such as fuel cells. A resonant converter is required for high efficiency systems. However, the peak value of the switches current is large in a resonant converter. This peak current requires a large number of switches and results in system failures. In this paper, an analysis and experiments of a resonant isolation push-pull converter are performed. A switching loss analysis is performed in order to compare losses between a resonant push pull converter and a hard switching push-pull converter. Specially, the conduction loss is studied based on the ratio between the resonant frequency and the switching frequency. In addition, a method for improving the efficiency is implemented with conventional HF insolation converters.

• Environmental and Resource Economics Review
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• v.13 no.3
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• pp.469-497
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• 2004

Environmental R&D management system has been analyzed with LCA method. Based on the analysis, we found the following four elements were essential for improving effciency of environmental R&D management system: establishment of an information clearinghouse that collects and distributes information on the status of the domestically owned environmental technology, Periodic survey of the environmental technology demand to give guidance in selecting the environmental R&D project that are to be subsidized, dissemination of information on the technology transfer and commercialization assistance program, and increased funding as well as the expansion of project categories eligible for R&D subsidy.

• Fire Science and Engineering
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• v.22 no.5
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• pp.99-104
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• 2008

As a part of improving early response system for senior emergency patients in rural areas in preparation for accelerated transition of Korea into aged society, this study seeks to make effective use of town broadcasting equipments and improve conventional educational ways for the first aid for senior people to boost up availability of private rescue personnel, so that it can contribute to improving capacity to early response to potential occurrence of emergency situations. In addition, this study focuses on profiling current activities of 119 geriatric Emergency Medical Services available in Korea, and also exploring possible ways to improve emergency services for senior safety which can play useful roles of social safeguard in imminent aged society as well as efficient ways to build up infrastructure for senior safety on the basis of opening up senior safety center.

• Fire Science and Engineering
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• v.24 no.3
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• pp.25-32
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• 2010

This research derived the perception with, and their remedies, in our country's fire cause investigation system by conducting survey on the working-level officials responsible for fire cause investigation in the fire stations and police stations. The results of the survey showed the necessity of establishing departments exclusively responsible for fire statistics management, broad area fire cause investigation task force, fire appraisal organizations besides National Institute of Scientific Investigation, standards for retaining fire investigation equipment, ways of improving technical education system, and improving the system for those who are specialized in arson (fire) cause investigation.

• Food Science of Animal Resources
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• v.36 no.6
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• pp.744-751
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• 2016

The objective of this study was to investigate the effects of partial beef fat replacement (0, 30, 50, 100%) with gelled emulsion (GE) prepared with olive oil on functional and quality properties of model system meat emulsion (MSME). GE consisted of inulin and gelatin as gelling agent and characteristics of gelled and model system meat emulsions were investigated. GE showed good initial stability against centrifugation forces and thermal stability at different temperatures. GE addition decreased the pH with respect to increase in GE concentration. Addition of GE increased lightness and yellowness but reduced redness compared to control samples. The results of the study showed that partial replacement of beef fat with GE could be used for improving cooking yield without negative effects on water holding capacity and emulsion stability compared to C samples when replacement level is up to 50%. The presence of GE significantly affected textural behaviors of samples (p<0.05). In conclusion, our study showed that GE have promising impacts on developing healthier meat product formulations besides improving technological characteristics.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.6 s.144
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• pp.666-672
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• 2005

Reduction of a ship's rolling is the most important performance requirement for improving the safety of the crew on board and preventing damage to cargos as well as improving the comfort of the ride. A mass driving anti-rolling system (MO-ARS) might be one candidate of several systems against the ship's rolling. In this paper, three types of MD-ARS, two passive and one active devices, are developed for small ships. After they are installed on the cabin of the small leisure boat, respectively, a series of performance test is conducted before and after operating them. Through the test, it is confirmed that the roll responses of the ship are pretty well reduced by the MO-ARS.

• Perspectives in Nursing Science
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• v.6 no.1
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• pp.77-83
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• 2009

The number of nurses per bed at acute-stage hospitals is quite low in Korea compared with other OECD countries. In order to prevent the degradation of the quality of inpatient nursing services due to insufficient nurse staffs, the national health insurance introduced the differentiated nursing care fee system. This did not work as a motive for inducing the employment of nursing staff due to insufficient cost compensation. Because of insufficient nursing staff, family members have to stay with the patient or patients have to hire a personal care attendant. This increases the burden and cost to families. For the activation of hospitals without guardians, there should be policies for raising additional nursing staff such as standardizing jobs among nursing staff, particularly between nurses and nursing assistants, setting adequate standards of staffing in nursing according to medical service, substantiating the cost of nursing under the differentiated nursing care fee system, improving the medical fee system of hospitals without guardians including health insurance payment, supplying nursing staff stably through improving their working conditions such as providing child rearing services and salary increase, clarifying the qualification of personal care attendants working at acute.stage hospitals, developing indexes for assessing the quality of nursing care services, and monitoring for the management of uniform quality.