• 한국항공우주학회지
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• 제43권12호
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• pp.1035-1047
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• 2015

고고도 장기체공 축소형 전기 동력 무인기(EAV-2H+)용 프로펠러의 성능을 평가하기 위해 풍동시험과 전산해석을 수행하였다. 3종의 프로펠러에 대해 성능 곡선을 측정하고, 운용 조건을 평가하여 EAV-2H+에 적용 가능 여부를 판단하였다. 낮은 rpm 영역에서 성능 계수의 저하 경향을 확인하였다. 프로펠러 성능에 미치는 강체 천이 테이프 부착 효과를 측정하고 분석하였다. 상용 전산유체역학 코드를 사용한 성능 해석을 수행하여 시험과 해석의 추력계수-동력계수 선도가 잘 일치함을 확인하였다. 전진비에 따른 성능 계수를 비교하고 결과 차이에 기여하는 시험장치의 영향을 평가하였다. 시험에서 관찰된 낮은 rpm 영역의 성능 감소 경향을 transition SST 모델이 유사하게 모사함을 확인하였다. 낮은 레이놀즈수에 의한 깃 요소의 공력 성능 저하가 프로펠러 성능 감소의 주원인으로 분석되었다. 고고도 조건 해석으로부터 프로펠러 성능 저하를 확인하였다.

• KIEAE Journal
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• 제17권4호
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• pp.59-65
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• 2017

Purpose: Thermal performance and air tightness of window are improved for the building energy efficiency. As the deteriorated houses are increased, the improve measures with low cost and easy installation are developed in the energy performance of window. Attached glazing and windbreak can be easily applied to the window with low cost. In this paper, the effect of the attached glazing and windbreak on the thermal performance and air tightness of window is analyzed as the measure to improve performance of window. Method: Thermal transmittance of glazing is evaluated through WINDOW simulation according to thickness of attached glazing and air cavity. Based on the simulation results, thermal transmittance, air tightness and condensation resistance performance of four cases are tested according to Korea standards. One type of PVC sliding double window is chosen as the specimen. For the analysis on low performance of window, the outside of window is excluded in the PVC sliding double window. Result: This study shows that thermal performance of glazing can be increased by the application of attached glazing. Furthermore, lower thermal performance of glazing can obtain the higher effect of attached glazing. The application of attached glazing and windbreak can effect on increasing thermal performance and air tightness of window.

• Journal of Ship and Ocean Technology
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• 제6권2호
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• pp.23-36
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• 2002

This paper describes the powering, seakeeping and maneuvering performances for a 2,500-ton class trimaran. Influence of the side-hull forms and location of those in longitudinal and transverse direction to resistance performance was systematically investigated by a series of model tests and numerical calculations. It was found that the longitudinal location of side-hulls was the most influential design parameter to the resistance performance of the trimaran and the optimum location of side-hull depends on ship speeds. When the side-hull stem is located near the primary wave hollow generated by the main hull, the trimaran shows the best resistance performance. Powering performance of the trimaran is superior to those of similar mono-hull ships. Seakeeping model tests for the trimaran were executed and the results were compared with the theoretical results of a similar mono-hull ship. Generally speaking, seakeeping performance of the trimaran is superior to that of a mono-hull ship. In particular, pitching and rolling performance of the trimaran is excellent, which is due to the increased length and breadth. Maneuvering model tests using a HPMM equipment were executed to evaluate the maneuvering performance of the trimaran. Maneuvering simulation was performed using the maneuvering coefficients from the model tests. The results show that the control ability of heading angle and the direction keeping stability of the trimaran is excellent, even though the turning performance is rather worse compared to those of a similar mono-hull ship.

• KEPCO Journal on Electric Power and Energy
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• 제4권2호
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• pp.81-88
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• 2018

발전소의 성능을 효율적으로 관리 및 유지하기 위한 발전소 성능평가는 매우 중요한 절차이다. 하지만 기존의 성능평가 방식은 엑셀 기반의 수작업 방식이다 보니 준비절차가 복잡하고, 범용성이 떨어지는 문제가 있었다. 이에 본 논문에서는 기존 성능평가 시스템의 문제점을 분석하고, 설비를 효과적으로 모델링하고 누락된 물성치를 계산하며, 이를 바탕으로 자동 지표계산을 수행하는 설비 모델러를 통해 성능평가의 범용성, 효율성 및 정확성을 높이는 방법을 기술하고자 한다.

• KEPCO Journal on Electric Power and Energy
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• 제7권2호
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• pp.295-299
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• 2021

Recently, interest in maintenance has been increasing due to the enlargement and aging of infra structures. Therefore, a new paradigm is required to secure and improve the durability of structures differentiated from the past. Accordingly, research on smart concrete incorporating the concept of self-healing into concrete is being actively conducted. In this study, the crack healing performance and durability performance of self-healing concrete applied with a hydrogel containing biomineral-forming microorganisms were evaluated. As a result of evaluating the dispersion of the hydrogel in concrete, it was confirmed that the hydrogel was well distributed in concrete matrix with a dispersion coefficient of 0.35 to 0.46. The crack healing performance evaluation was verified by a water permeability test, and showed a recovery rate of 95% or more at the age of 28 days, confirming the applicability of self-healing concrete. The durability performance of self-healing concrete was evaluated in terms of resistance to penetration of chloride ion and freezing and thawing. Regardless of the mixing of the hydrogel, the same level of durability performance was shown for various compressive strength level. Therefore, it was confirmed that the microbial admixture did not affect concrete durability. In the future, long-term crack healing performance and durability verification studies should be supplemented.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1166-1169
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• 2009

Bridges are exposed to very severe environment and experience, as service life increased, elevated traffic load and traffic flow, in addition to natural disasters. In comparing to other road structures, bridges may cause more significant damage, such as human-involved accidents, to the society in the event of collapse. A certain level of service shall be necessarily secured to assure the minimum safety of users. The cost for manage and preserve bridges will increase gradually and more restrictions will be loaded to efficiently distribute the limited resources, such as monetary budget and human resource etc. In order to enhance performance and serviceability of bridges with the limited resource, asset management technique has been applied into the bridge management system, which capitalizes the road infrastructures including bridges and assess them in accordance with the government finance report. In the application of asset management, there must be a tool for assess the performance of bridges and this study introduces the basic information on the definition and role of performance measures for asset management for bridges. This research suggests future development direction of performance measure for asset management for bridges in Korea.

• 복합신소재구조학회 논문집
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• 제3권2호
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• pp.36-46
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• 2012

Structure Insulated Panel (SIP) is an wooden structure material with which structure and insulation functions are satisfied. Hence, it would be a cost-effective model to implement low energy house which has higher insulation and structure performance and which the wall thickness is able to be reduced. In this study, performance of thermal insulation and fire resistance were evaluated in order to verify applicability to low energy house. Fire resistance test is performed on vertical load bearing members for partitions, and the test results satisfy one hour of fire resistance condition according to KS F 2257. The members include two layers of fireproof gypsum board with thicknesses of 12.5mm attached to SIP. Thermal insulation performance is satisfied with the 2012 standard ($0.225W/m^2{\cdot}K$). As the performance of resistance and thermal insulation are satisfied, SIP is expected to be applied to low energy building materials. In the future, the structural safety will be confirmed by structural performance and seismic performance test and the guidelines for distribution will be drawn up.

• 한국콘텐츠학회논문지
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• 제20권9호
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• pp.355-364
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• 2020

예산의 성과계획서는 예산과 성과를 연계하고 성과 중심적인 정책 수행을 위하여 도입되었다. 본 연구는 성과지표가 사업부서별로 어떻게 계획되고 달성되는지 알아보기 위하여 제주특별자치도의 2020년도 농업 분야 예산의 성과계획서를 대상으로 성과지표의 적정성에 대해 검토하였다. 분석결과 정책사업과 목표 간 낮은 연계성, 성과지표에 대한 가중치와 목표치에 대한 근거 불명확, 성과지표의 낮은 도전성 등의 문제점이 있었으며, 다수의 성과지표가 실적 중심의 산출지표였다. 이러한 문제점을 개선하기 위해서는 도전적인 성과지표와 인센티브를 통한 실질적인 성과지표 구축이 필요하다.

• 보건의료산업학회지
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• 제10권1호
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• pp.27-37
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• 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.

• 산업경영시스템학회지
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• 제23권57호
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• pp.41-49
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• 2000

This paper investigates the relation between operating performance and initial underpricing of companies that go public. A significant decline in operating performance subsequent to the initial public offering(IPO) is found. Additionally there is a significant positive relation between post-IPO operating performance and the level of initial underpricing.