• Advances in concrete construction
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• 제9권4호
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• pp.413-421
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• 2020

For steel-concrete girders made composite using shear studs, initial damage on studs induced by weld defect, unexpected overloading, fatigue and others might degrade the service performance and even threaten the structural safety. This paper conducted a numerical study to investigate the static behavior of damaged stud shear connectors that were embedded in ultra high performance concrete (UHPC). Parameters included damage degree and damage location. The material nonlinear behavior was characterized by multi-linear stress-strain relationship and damage plasticity model. The results indicated that the shear strength was not sensitive to the damage degree when the damage occurred at 2/3d (d is the stud diameter) from the stud root. An increased stud area would be engaged in resisting shear force as the distance of damage location from stud root increased and the failure section becomes inclined, resulting in a less reduction in the shear strength and shear stiffness. The reduction factor was proposed to consider the degradation of the shear strength of the damaged stud. The reduction factor can be calculated using two approaches: a linear relationship and a square relationship with the damage degree corresponding to the shear strength dominated by the section area and the nominal diameter of the damaged stud. It was found that the proposed method is preferred to predict the shear strength of a stud with initial damage.

• Journal of Advanced Marine Engineering and Technology
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• 제35권2호
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• pp.182-188
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• 2011

본 논문은 R744-R404A용 캐스케이드 냉동시스템의 기초 설계자료를 제공하기 위해서 성능특성에 대해 분석하였다. 작동변수로는 R404A용 고온사이클과 R744용 저온사이클의 과냉각도와 과열도, 압축효율, 응축과 증발온도이다. 이에 대한 주요결과를 요약하면 다음과 같다. 고온사이클에만 과열도를 주는 것이 가장 높은 COP를 가지는 반면에 저온 고온사이클 모두에 대해 과냉도를 주는 것이 가장 높은 COP를 가진다. 과열도, 과냉각도, 압축효율, 증발온도, 응축온도 등의 인자들이 R744와 R404A용 캐스케이드 냉동사이클의 COP에 영향을 미치는 것을 확인할 수 있었고, 이들 각각의 인자들은 캐스케이드 냉동사이클의 성능을 최대로 하는 캐스케이드 증발온도가 존재함을 알 수 있었다.

• 한국의료질향상학회지
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• 제21권1호
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• pp.52-61
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• 2015

Objectives: Because recently hospital had to faced with financial hardship, we have to have more effective hospital management. The purpose of this study was to reduce loss costs of the hospital through the systematic management of medical supplies and increase operational efficiency. Methods: The team was composed of outpatient nursing staff, medical record administrator, nurses in medical insurance, medical computer center, dermatologists for this study. We surveyed for 114 people including outpatient nursing staff, nurse aids, medical assistant, physician assistant. Pre-survey period was 2013.03.11 ~ 03.30(2 weeks), and post-survey period was 2013.09.03 ~ 09.17(2 weeks). Result: We improved this way through the computational improvement, conservation campaigns, inventory management, staff training, replaced by low-cost medical supplies. The finding of this study were as follows: Comparing before and after the activity of outpatient nursing staff's degree of knowledge, performance, economic consciousness, the degree of knowledge, performance was increased, but there was no significant change in economic consciousness. Performance of Married person is higher than the unmarried, In addition, the high-position people were more the degree of knowleage, economic consciousness. After activity, correlation of goods and treatment, examinations is increasing, but statistically there was no mean. Conclusion: This study revealed that knowledge in a short period of activity, but also can improve, perform the same change in behavior is not easy. This one shows the intensive training required to sustained and systematic behavioral changes, such as changes in behavior, perform rituals to help the economy. Expensive medical supplies to replace a similar effect as the cost of materials just to have a lot of cost savings. Therefore, more medical supplies change is necessary to develop alternative treatment and cost cutting.

• 한국건설관리학회논문집
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• 제22권6호
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• pp.138-146
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• 2021

철근콘크리트 구조물내 교차된 양단 135° 표준갈고리 작업성을 향상시키기기 위하여 한쪽 90° 갈고리에 결속 보강함으로서 135° 표준갈고리와 대등한 성능을 발휘하는 원터치 방식의 철근보강클립(RCC장치)을 제안하였으며, 다양한 성능실험과 해석, 시공성 평가 및 경제성 분석을 통하여 개발 완료하였다. 2020년 6월부터 적용된 총 13개 현장을 분석한 결과, 개발할 당시의 예상한 것과 같이 구조감리나 공사감독관의 지적에 대해 불가항력적인 조치사항으로 적용하는 사례가 대부분이었다. 그러므로 현장성과분석을 통하여 효율적이고 자발적인 철근보강클립의 사용을 위해 원도급자가 우선 구매 후 협력엽체와 계약한 다음 제공하는 방식 등의 여러방식을 제안하였다. 결과적으로 철근보강클립을 적극적인 활용함으로써 현장에서 품질과 공정관리 측면에서 기여도가 매우 클 것으로 예상된다.

• 한국산학기술학회논문지
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• 제19권1호
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• pp.456-465
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• 2018

본 연구의 목적은 위암 수술환자의 구체적 자기효능감, 가족지지와 자가간호수행의 관계를 파악하기 위함이다. 자료수집은 2013년 10월 11일에서 동년 11월 15일까지였으며, B시에 소재한 D대학병원에서 위암 진단 후 치료목적으로 수술을 받은 후 3개월이 경과하고 5년 이내의 추후관리 중인 환자 121명을 대상으로 설문조사 하였다. 자료분석은 SPSS/PC WIN 18.0 프로그램을 이용하여 실수와 백분율, 평균, 평균평점과 표준편차, t-test, ANOVA와 Scheffe's test, Pearson's correlation coefficients 및 stepwise multiple regression으로 분석하였다. 위암 수술환자의 제특성에 따른 자가간호수행 정도는 성별(t=-2.25, ｐ=.027), 종교(F=3.67, ｐ=.028), 직업(F=4.17, ｐ=.008)에 따라 통계적으로 유의한 차이가 있었다. 위암 수술환자의 자가간호수행은 구체적 자기효능감과 정적인 상관관계를 보여주었다(r=.60, ｐ<.001). 위암 수술환자의 자가간호수행 관련요인은 구체적 자기효능감, 종교 및 성별로 나타났다. 전체 설명력은 37.9%였으며, 가장 큰 영향요인은 구체적 자기효능감 (${\beta}=.53$)으로 나타났다. 따라서 위암 수술환자의 자가간호수행을 돕기 위해서는 구체적 자기효능감을 높이는 중재를 제공하는것이 필요하며, 종교 및 성별을 활용한 실질적인 방안을 마련해야 할 것이다.

• 디지털융복합연구
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• 제17권3호
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• pp.139-152
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• 2019

4차 산업혁명과 융복합 시대를 맞아 국내 대학들도 교육의 질 개선을 비롯한 적극적인 변화가 요구되는 상황에서 1주기 전문대학의 기관평가인증제에 대한 대학의 대응 노력이 대학의 BSC 관점의 지각된 경영성과에 미치는 영향에 대한 실증분석을 목적으로 하고 있다. 연구 모형을 검증하기 위하여 1주기 기관평가인증제 심사를 받은 전문대학을 대상으로 152부의 설문지를 표본으로 하여 SPSS v.18을 이용하여 검정하였다. 분석 결과 평가인증제에 대한 대학의 대응 노력 중 평가인증제에 대한 관심 정도는 학습과 성장 성과에만 영향을 미치며, 평가인증 준비의 적절성은 고객 성과, 내부프로세스 성과, 재무 성과에 영향을 미치며, 자체평가의 만족도는 BSC 4가지 관점의 성과 모두에 영향을 미치는 것으로 나타났다. 본 연구의 결과는 기관평가인증제를 통한 대학의 경영성과 관리방안을 강구하는데 유용하게 활용될 수 있을 것이다. 향후 기관평가인증제를 대학 경영성과의 확대로 연결 지을 수 있는 발전된 연구가 필요하겠다.

• International Journal of Control, Automation, and Systems
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• 제3권2호
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• pp.202-210
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• 2005

This paper presents a new neural network control for nonlinear bridge systems with earthquake excitation. We design multi-layer neural network controllers with a single hidden layer. The selection of an optimal number of neurons in the hidden layer is an important design step for control performance. To select an optimal number of hidden neurons, we progressively add one hidden neuron and observe the change in a performance measure given by the weighted sum of the system error and the control force. The number of hidden neurons which minimizes the performance measure is selected for implementation. A neural network was trained for mitigating vibrations of bridge systems caused by El Centro earthquake. We applied the proposed control approach to a single-degree-of-freedom (SDOF) and a two-degree-of-freedom (TDOF) bridge system. We assessed the robustness of the control system using randomly generated earthquake excitations which were not used in training the neural network. Our results show that the neural network controller drastically mitigates the effect of the disturbance.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2119-2123
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• 2007

This study deals with performance characteristics of heat pipe combined with a solid-liquid phase change material(PCM). The outer diameter of the heat pipe was 9.5 mm and the total length was 600 mm, where the evaporator, the adiabatic section and the condenser lengths were equally 200 mm. A paraffin wax having a melting point of 58.5$^{\circ}C$ was used as PCM. The paraffin container was attached to the adiabatic section of the heat pipe. The paraffin container had outer diameter of 18 mm, wall thickness of 1.2 mm and the total length of 100 mm. The heat pipe was tested with tilt angle of horizontal degree and favorite angle 10 degree, with evaporator lower position to provide stable operation of the heat pipe. Input thermal load was varied from 40 W, with increment of 40 W, to above 100 W until the maximum temperature of the heat pipe wall reached 200$^{\circ}C$. Test results of the PCM heat pipe were presented in comparison with conventional heat pipe of the same basic dimensions. The performance was analyzed in terms of temperature distribution, thermal resistance and heat transport capability.

• Journal of Biosystems Engineering
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• 제26권2호
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• pp.131-140
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• 2001

This study was conducted to develop a garlic separator which could to reduce the labor in preparation of seeding. After consideration of the design criteria of a garlic separator such as no additional conveying device, simple construction and operation, enhancement of separating efficiency, reduction of damage, degree a rotating corn type garlic separator was designed. The effects of design parameters such as height and angle of the inner and outer corns, rotating speed of inner corn on the separating performance of the prototype were estimated. In performance was compared with manual work. The results are summarized as follows. 1. Garlic bulbs were separated by a spiral movement in the gap between inner rotating corn and outer fixed corn. At constant feed rate of garlic bulbs, the capacity of garlic separation increased with increase of rotating speed of inner corn. Especially, the capacity was very high at the rotating speeds of 300 and 400rpm. 2. The damage degree of separated garlics increased with rotating speed of corn within 10%. Above 300rpm, separability of Uisung garlic was about 100% and incomplete separation of Namdo garlic was within 2%. 3. The capacity of prototype garlic separator developed in this study was 30 times as large as that of human being.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.97-102
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• 2007

As environmental vibration requirements on precision equipments get more stringent, use of pneumatic vibration isolators becomes more crucial and, hence, their dynamic performance needs to be further improved. Dynamic behavior of those pneumatic vibration isolation tables is very important to both manufacturer and customer as performance specifications. Together with conventional transmissibility, transient response characteristics are another critical performance index especially when movements of components, e.g., x-y tables, of the precision equipments are very dynamic. In this paper, analysis on transient response of a pneumatic vibration isolation table loaded by a mass moving on it is presented. This is a conventional dynamics problem on a rigid body with 6 degree of freedom and a mass with another degree of freedom. How to obtain transient responses of the isolation table is described when the movements of the mass are prescribed relative to the table.