• 유공압시스템학회논문집
• /
• 제6권1호
• /
• pp.17-24
• /
• 2009

The performance improvement of a small-size integrated-type fully hydraulic breaker is studied in this paper. Mathematical modeling of the breaker is established and verified by experiment. Through sensitivity analysis using AMESim, the key design parameters are selected and nearly optimized to maximize the impact energy as well as to improve the dynamic characteristics such as the piston upper chamber pressure, piston and valve displacements. As a result, the impact energy, blows per minute(bpm) and output power are increased by 52.9%, 1%, and 55.6%, respectively compared with the current design. The dynamic characteristics of the piston upper chamber pressure, piston and valve displacements are also improved by the design change.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
• /
• pp.211-212
• /
• 2015

Procurement and lifting scheduling of modules and resources in modular construction, where modules that are manufactured from factory are delivered and assembled on site, is a crucial factor that determines the efficiency of the whole construction. However, previous studies have barely acknowledged the significance of resource procurement process and lifting of modules in modular construction. Therefore, this research aims to derive factors that are in need of improvement for successful implementation of procurement and lifting efficiency, and visualize them according to their importance and performance on improvement through IPA(Important Performance Analysis).

• 대한안전경영과학회지
• /
• 제19권1호
• /
• pp.145-156
• /
• 2017

This study was conducted to grasp problems of the present and investigate the real condition of organizations by making how an organizational ISO/TS 16949 quality management system has a positive effect on process improvement, perceived organizational support has a significant effect on the relationship between ISO/TS 16949 requirements and process improvement, process improvement has a positive effect on customer satisfaction and organizational performance research projects. For doing them, it tris to suggest an effective application plan of ISO/TS 16949 certification through improvements about corporate quality management systems of the automobile field by investigating and analyzing literature of the precedent studies and ISO/TS 16949 certification effects actually, conducting and analyzing an survey on effects on customer satisfaction and organizational performance, and drawing the problems.

• 한국정보통신학회논문지
• /
• 제2권1호
• /
• pp.19-26
• /
• 1998

본 논문에서는 추적 성능 개선을 위해 기존의 신경망 제어기에 PID제어기를 직렬로 연결하여 시뮬레이션 결과를 고찰했다. 추적 성능을 평가하기 위해 신경망모델은 2계층으로 구성하고 Widrow-Hoff델타 규칙을 이용하여 예측 오차가 최소화되도록 정규적인 동특성을 학습하였다. 이 학습 결과, 기존의 신경망제어기의 경우보다 PID를 연결하였을 경우가 추적 성능이 다소 개선되었음을 확인했으며, 251샘플에서 추적할 플랜트 파라메터가 시변인 경우에도 빠른 속도로 수렴되는 결과를 얻었다.

• Journal of Advanced Marine Engineering and Technology
• /
• 제20권3호
• /
• pp.137-143
• /
• 1996

The propulsion marine diesel engine has been widely applied with a mechanical-hydraulic governor to control the ship speed for long time. But it was recently very difficult for the mechanical-hydraullic governor to control the speed of engine under the condition of low speed and low load because of jiggling and hunting by rough fluctuation of rotating torque. To solve these problems of control systems, the performance improvement of mechanical-hydraulic governor is required. In this paper, in order to analyze the speed stability of control systems, the influence of parameters of the engine dead time, gain, damping ratio was discussed on the view of control engineering. The performance improvement of a conventional mechanical hydraulic governor is confirmed to be possible by fuzzy control scheme.

• 설비공학논문집
• /
• 제20권10호
• /
• pp.637-644
• /
• 2008

Auxiliary port which had been known to be used to reduce the expansion loss of a refrigeration system was applied to a R134a reciprocating compressor in a household refrigerator cycle with an intention of improving the compressor performance. Effects of the auxiliary port on the compressor performance was investigated by a computer simulation program. When a simple hole was made on the side wall of the cylinder as an auxiliary port and surrounding gas inside the compressor shell was assumed to be drawn into the cylinder through the hole, maximum COP improvement of 1.66% was obtained. With auxiliary port equipped with a plate type of check valve, maximum COP was raised to be 1.99%. COP improvement was more distinctive with decreasing the discharge pressure; COP improvement was 5% with discharge pressure of 7 bar.

• International Journal of Internet, Broadcasting and Communication
• /
• 제11권2호
• /
• pp.76-83
• /
• 2019

In this paper, we propose the beamforming algorithm for the performance improvement of MIMO MC-CDMA system. The proposed multibeamforming of MIMO MC-CDMA structure having the same number of beamformer as the number of transmit antenna is derived by calculating the error signals between the coded pilot symbols and the corresponding received signals from the multiple transmitters of the desired user in the frequency domain, transforming the frequency-domain error signals into time-domain error signals, and updating the weights of the multibeamformer in the time-domain in the direction minimizing the mean squared error (MSE). The proposed approach can track each direction of arrival (DOA) of the signals from multi-antennas of a desired user. The performance improvement is investigated through computer simulation by applying the proposed approach to MIMO MC-CDMA system in a multipath fading channel with multiusers.

• Asia pacific journal of information systems
• /
• 제29권2호
• /
• pp.217-247
• /
• 2019

This paper draws on the interdependence theory to examine the role of power and mutual dependence on the relationship between internal/external diffusion and performance improvement within a supply chain. The results from a survey of 375 respondents show that two patterns of IOS diffusion - internal diffusion and external diffusion - have different impacts on a firm's performance improvement according to differences in power and mutual dependence between two parties in the supply chain.

• 보건의료산업학회지
• /
• 제10권1호
• /
• pp.27-37
• /
• 2016

Objectives : This study applied the research model of Bontis (1998), which has been used to investigate everything from business corporations to hospitals in Korea, examined its generalizability and attempted to verify which factors of the intellectual capital affects organizational performance, represented by indicators for the clinical and financial performance of hospitals. Methods : Primary data for the study were collected from 91 general hospitals through self-administered questionnaires, and secondary data on clinical and financial performance of hospitals were collected form existing statistics. Collected data were analyzed with SPSS 11.5 (ver.) and AMOS 18.0 (ver.). Results : It was found that only human capital and customer capital had indirect effects on hospital performance. It was also revealed that structural capital had a direct effect on clinical performance, and an indirect effect on financial performance. Conclusions : This result means that there is a need to individually consider both the clinical performance and financial performance when measuring the organizational performance of a hospital, and it also shows that positive improvement in the clinical performance can contribute to the improvement of the financial performance through this process.

• 한국산학기술학회논문지
• /
• 제22권4호
• /
• pp.67-74
• /
• 2021

국내에서 항만의 방파제는 안전점검 및 안전진단을 통해 기술적 상태평가를 수행하고, 필요 시 해당 시설물에 대해 유지관리를 수행한다. 그러나 최근 생애주기비용(Life Cycle Cost, LCC) 측면에서 기반시설에 대한 관리의 필요성이 증가함에 따라 「지속가능한 기반시설 관리 기본법」이 제정되고, 방파제의 기술적 부분만 평가했던 기존 평가방식에 경제성 평가 및 정책성 평가가 추가되어 성능개선을 통해 방파제에 대한 종합적인 관리가 가능해질 것으로 예측하고 있다. 이러한 이유로 본 연구는 「지속가능한 기반시설 관리 기본법」에서 규정하고 있는 총공사비 500억 미만의 방파제 성능개선사업을 대상으로 성능개선사업의 세부평가항목 및 방법 등을 개발하여 평가방안을 제시하고, 향후 실무에 적용될 성능개선 평가를 위한 방파제 성능개선 평가항목 및 평가방법의 개발 방향을 제시하는 것을 목적으로 연구를 수행하였다. 본 연구는 유지관리 및 성능개선의 개념 검토, 성능개선 관련 문헌조사, 성능개선 공통기준 사업유형 검토, 방파제 성능개선 평가항목 및 평가방법(안) 도출, 전문가 검토 등의 순서로 수행하였으며, 도출한 방파제 성능개선에 대한 평가방안은 지금까지 기술적 상태평가에 국한된 유지관리 업무에 성능개선을 적용한 구체적인 평가방법을 제시한 것으로 시설물의 선제적 관리 및 안전사고 예방에 활용 가능할 것으로 기대된다.