• 한국시뮬레이션학회논문지
• /
• 제23권4호
• /
• pp.229-235
• /
• 2014

생산시스템의 시간과 비용 효율성을 개선하는 것은 경쟁 우위를 구축하고 경쟁적인 비즈니스 환경에서 수익성을 향상하는 중요한 수단 중 하나이다. 그 중에서도 CONWIP(constant work-in-process)과 DBR(drum-buffer-rope)방법은 생산 공정의 효율을 개선하는 데 널리 사용된다. 이 연구에서는 실제 단추 공장 생산 시스템의 시뮬레이션 모델을 개발했다. 연구 결과에 의하면, CONWIP과 DBR 생산시스템 모두 병목 공정의 대기 시간을 감소시키는 등 실제 생산시스템보다 나은 결과를 나타냈다. 시뮬레이션 모델 결과를 바탕으로 제안된 생산시스템을 적용함으로써, 실제의 제조 공정의 효율을 크게 향상시킬 수 있을 것으로 기대된다.

• Structural Engineering and Mechanics
• /
• 제64권2호
• /
• pp.195-204
• /
• 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.

• 한국기계가공학회지
• /
• 제19권1호
• /
• pp.29-35
• /
• 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
• /
• 제12권3호
• /
• pp.418-428
• /
• 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.

• 자원ㆍ환경경제연구
• /
• 제13권3호
• /
• pp.469-497
• /
• 2004

환경 R&D 예산의 효율성 제고 방안의 연구를 위해 전주기방법에 입각하여 환경 R&D 사업의 운영체계에 대한 문제점과 개선방안을 제시하였다. 연구결과 크게 네 가지 부문의 개선 노력이 요구되는 바, 첫째, 기술현황에 관한 기초자료를 축적 관리하는 전담조직의 운영, 둘째, 주기적 기술수요조사를 통한 과업선정체계의 강화, 셋째, 국가연구개발사업으로 추진된 개발기술의 상용화 자금지원제도에 대한 홍보 알선 업무의 강화, 그리고 마지막으로 이전기술의 사업화를 위한 지원기관, 대상사업 및 재정지원의 확대가 가장 필요한 것으로 결론지어졌다. 그러나 R&D 지원사업의 운영체계에만 국한하여 분석한 본 연구의 한계를 극복하기 위해서는 R&D 사업의 전반에 관한 포괄적인 추후 연구를 추진할 필요가 있다.

• 한국화재소방학회논문지
• /
• 제22권5호
• /
• pp.99-104
• /
• 2008

최근 우리나라는 고령화 사회에 빠르게 진입되었다. 농촌지역의 노인 응급환자 초기 대응 시스템 개선을 위해 마을 방송 장비의 활용과 노인을 위한 응급처치 교육방법의 개선으로 보다 많은 민간구조자원을 확보하여 응급상황 발생시 초기대응 능력을 향상시키고자 본 연구를 실시하였다. 현재 우리나라 119의 노인 응급의료서비스 실태를 살펴보고, 고령화 시대 사회적 안전장치의 역할을 충실히 수행할 수 있는 노인 안전을 위한 구급서비스 개선 방안 및 노인안전 센터 개설로 인한 노인안전 인프라 구축 방안을 모색하고자 하는데 본 연구의 목적이 있다.

• 한국화재소방학회논문지
• /
• 제24권3호
• /
• pp.25-32
• /
• 2010

본 연구는 우리나라에서 방화원인조사를 주로 담당하고 있는 소방과 경찰관서의 실무자들을 대상으로 설문조사를 실시하여 방화원인조사에 관한 인식을 조사하였다. 설문조사결과 방화통계관리를 위한 전담부서의 설치, 광역 방화원인조사전담팀의 설치, 국립과학수사연구소 이외의 화재감정기관의 설립, 화재조사 장비 보유기준 제정, 방화(화재)원인조사 전문교육제도의 개선, 방화(화재)원인조사 담당자들의 전문화를 위한 제도개선 등이 필요한 것으로 나타났다.

• 한국축산식품학회지
• /
• 제36권6호
• /
• pp.744-751
• /
• 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.

• 대한조선학회논문집
• /
• 제42권6호
• /
• pp.666-672
• /
• 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
• /
• 제6권1호
• /
• pp.77-83
• /
• 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.