• Structural Engineering and Mechanics
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• 제66권2호
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• pp.161-172
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• 2018

The passive control of structures using a pendulum tuned mass damper has been extensively studied in the technical literature. As the frequency of the pendulum depends only on its length and the acceleration of gravity, to tune the frequency of the pendulum with that of the structure, the pendulum length is the only design variable. However, in many cases, the required length and the space necessary for its installation are not compatible with the design. In these cases, one can replace the classical pendulum by a virtual pendulum which consists of a mass moving over a curved surface, allowing thus for a greater flexibility in the absorber design, since the length of the pendulum becomes irrelevant and the shape of the curved surface can be optimized. A mathematical model for a building with a pendular tuned mass damper and a detailed parametric analysis is conducted to study the influence of this device on the nonlinear oscillations and stability of the main system under harmonic and seismic base excitation. In addition to the circular profiles, different curved surfaces with softening and hardening characteristics are analyzed. Also, the influence of impact on energy dissipation is considered. A detailed parametric analysis is presented showing that the proposed damper can not only reduce sharply the displacements, and consequently the internal forces in the main structure, but also the accelerations, increasing user comfort. A review of the relevant aspects is also presented.

• 설비공학논문집
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• 제11권3호
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• pp.301-312
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• 1999

Experiments were carried out to evaluate performance of the cold air distribution systems with an ice storage tank in test room. Cold air distribution systems provide primary air for comfort conditioning or process cooling at coil discharge temperatures$4^{\circ}C$ to$11^{\circ}C$. The application of a cold air distribution system allows for the downsizing of air distribution equipment and central plant equipment when ice storage tank is used. The benefit of a cold air distribution system include a decrease in the floor-to-floor height, increase floor space, reduced building capital costs, reduced energy use and demand. The use of cold air distribution can result in the most cost effective system and is currently being implemented world wise as the new standard in air conditioning systems. In this study, the cold air distribution system is compared with the general ice storage system. Under the same cooling load conditions, experimental results show that the supply air volume of cold air distribution system decrease 38%, and decrease 45% flow rate of brine for the general ice storage system.

• 설비공학논문집
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• 제27권12호
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• pp.620-625
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• 2015

The summer climate is very hot and humid in Korea. Humidity is an important factor in determining thermal comfort. Recently, research on dehumidification device development has been attempted to save the energy required for operating the dehumidifier. Existing dehumidification systems have disadvantages such as wasting energy to drive the compressor. Meanwhile, dehumidification systems with membranes can dehumidify humid air without increasing the dry bulb temperature. Therefore. they don't have to consume cooling energy. In this paper, the installation conditions for a membrane system were analyzed to improve the shape and optimum performance of the system. The results showed that the distance between elements was the critical system design factor, and that a distance of 20 mm was the optimal condition for the pressure drop and flow characteristics of the internal air flow.

• 설비공학논문집
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• 제29권3호
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• pp.105-110
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• 2017

Underfloor air distribution (UFAD) is an air distribution strategy for providing ventilation and space conditioning in buildings. UFAD systems use the underfloor plenum beneath a raised access floor to provide conditioned air through floor diffusers that create a vertical thermal stratification during cooling operations. Thermal stratification has significant effects on energy, indoor air quality, and thermal comfort performance. The purpose of this study was to characterize the influence of a linear bar grille diffuser on thermal stratification in both interior and perimeter zones by developing Gamma-Phi based prediction models. Forty-eight simulations were carried out using a Computational Fluid Dynamics (CFD) technique. The number of diffusers, the air flow supply, internal heat gains, and solar radiations varied among the different cases. Models to predict temperature stratification for the tested linear bar grille diffuser have been developed, which can be directly implemented into dynamic whole-building simulation software such as EnergyPlus.

• 대한인간공학회지
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• 제25권4호
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• pp.71-80
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• 2006

A construction robot has been developed for higher productivity and better safety in various construction fields. Especially, curtain wall is suitable for outer wall material of tall commercial building and apartment complexes. This heavy material is, however, hard to install with a manpower and outdated equipment. For this reason, the prototype of ASCI (Automation System for Curtain wall Installation) was developed. This system has a robot controller(i.e. hand-held remote control unit) for the transfer information signal between human operator and robot system. Although study has been conducted on manual controller of ASCI, hardly any information is known about the operator's opinion. In this study, a questionnaire was completed by operator to get their opinion about aspects which need to design a more comfortable and productive manual controller of construction machinery, robot included. Through the result of study, it is expected that this technical data is contributed to the robot controller design for comfort and productivity of various industrial machinery.

• 지역사회간호학회지
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• 제13권3호
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• pp.566-573
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• 2002

A concept is a building block of a theory. The purpose of a concept analysis is to clarify the critical attributes of a concept and identify its real meaning, particularly if the concept is not understood in a clear and accurate manner. This study was conducted to analyze the concept of support, which has been adopted from another discipline and unclearly used in nursing science. For concept analysis of this study, Walker and Avant's method was used. Support is defined as a domain with emotional. informational. material and evaluative aspects. Critical attributes of the concept of support included (1) an experience of support between a support provider and a client, (2) communication, (3) a relationship of mutual interchange of emotional, informational, material, evaluative support, and (4) intention, Cases related to the concept of support included model cases and appendix cases (against. boundary, and related). Antecedents of support were anxiety, depression, and loss of self-esteem, and consequences of support were comfort, increase of self-esteem, and trust. Based on these results, a nursing intervention that can provide a better quality of life for the prevention of diseases, health management, and health promotion may be developed in the future.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.729-732
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• 2008

최근 실내공기질에 대한 관심이 집중되고 있는 가운데 이를 개선하고자 하는 노력이 다각도로 진행되고 있다. 본 연구는 기존의 친환경 마감재 적용 기술과 달리 콘크리트 자체에 활성탄과 흡착된 오염 공기를 분해할 수 있도록 기능성 촉매를 혼입함으로써 기본적인 물성과 포름알데히드 제거율을 시험하여 공기정화 효과를 분석하고자 하였다. 실험 결과 활성탄의 첨가량 증가에 따라 슬럼프는 감소하는 경향을 나타내었고, 압축강도는 큰 차이 없이 유사한 것으로 나타났다. 공기질 개선과 관련하여 포름알데히드 제거율을 시험한 결과 최대 80%까지 제거하는 것으로 나타났다.

• 대한간호학회지
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• 제46권6호
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• pp.858-870
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• 2016

Purpose: The purpose of the study was to explore and describe the adaptation process of older people to group homes. Methods: Participants were twenty older adults aged 65 or older who were living in group homes. Data were collected from January to April, 2015. In-depth unstructured interviews were conducted with individual participants. Data were analyzed using Strauss and Corbin's grounded theory method. Results: From open coding, 100 concepts, 38 sub-categories, and 14 categories were identified. Analysis showed that the central phenomenon of the adaptation process of older people to group homes was 'gradually giving up'. Causal conditions were 'good-for-nothing body', contextual conditions were 'pushed', 'beleaguered'. Intervening conditions were 'reliable pillar: children', 'having affection (情) more than having it from family: facility workers', 'comfort - like feeling at home', 'relieved: system'. Action/interaction strategies were 'facing the unfamiliar reality', 'building relationships with other people', 'accepting reality'. Consequences were 'a good place, more than expected', 'hope for the remaining days', 'waiting for a peaceful death'. Conclusion: The results of this study provide an in-depth understanding of the experience of the adaptation process of older people to group homes. The findings from this study can be used as basic data to establish policies to increase the number of small scale facilities which can help older adults adapt easily to the facilities.

• KIEAE Journal
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• 제10권6호
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• pp.139-144
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• 2010

The demands are increasing for the efficient heating and cooling system and thermal comfort environment because of changes in climate and environment, and deterioration of buildings and facilities can cause education budget to increase. So the study to apply heating and cooling system to university is urgently needed to improve an optimum energy saving system, educational environment and convenience of maintenance. For this reason, we selected a university campus in Seoul then came to understand the current situation and found some problems. We drew alternatives from comparative analysis of them. It selects representative building and carries out economic analysis to evaluate characteristics of energy consumption and economics on each type of heating and cooling system. As a result we drew the optimum system from those processes as previously stated. We studied 3 available systems, absorption chiller, EHP(Electric Heat Pump) and GHP(Gas Engine Heat Pump). According to LCC analysis suppose that the value of EHP is 1, it came out that the value of absorption chiller is 1.5 and the value of GHP is 2.2. This study, suggesting the optimum heating and cooling system, will support educational and research activities furthermore effect to maximize energy efficiency. Ultimately it is expected that it will contribute to make eco-friendly Green Campus.

• KIEAE Journal
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• 제9권5호
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• pp.105-113
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• 2009

Daylighting provides the opportunity for both energy savings and improved visual comfort. An accurate estimation of the amount of daylight entering a building is the key step for daylight designing. This research aims to assess comparative daylighting performance of four different configurations of fenestration in case of unilateral windows and their variation under clear and overcast sky conditions. The selected window openings in this study were single punched, double punched, multiple punched and clerestory, and the area was same for each type of window. The experiment was designed for an office space using 1/10 scale model. Daylighting performance was evaluated by measuring the illuminance on work-plane height using Agilent data logger and photometric sensor Li-Cor. Thecomputer program ECOTECT was also used to simulate the pattern of interior illuminance distribution. Clerestory window showed the best performance in term of both illuminance level and distribution in the experiment. Multiple punched window provided more uniform illuminance distribution than single punched window. Lowest daylighting performance in the experiment was shown by double punched window.