• 설비공학논문집
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• 제27권7호
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• pp.375-379
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• 2015

A proper estimate of solar cell efficiency is of great importance for the feasibility analysis of solar cell power plant development. Since solar cell efficiency depends on temperature, several methods have been introduced to measure it by operating temperature modulation. However, the methods either rely on the external environment or need expensive equipment. In this paper, a thermoelectric module was used to control the operating temperature of crystalline silicon solar cells effectively and precisely over a wide range. The output characteristics of crystalline silicon solar cells in response to operating temperatures from $-5^{\circ}C$ to $100^{\circ}C$ were investigated experimentally. Their efficiencies decreased as the temperature rose, since the decrease in the open circuit voltage and fill factor exceeded the increase in the short circuit current. The maximum power temperature coefficient of the single crystalline solar cell was more sensitive to temperature change than that of the polycrystalline solar cell.

• 설비공학논문집
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• 제23권2호
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• pp.139-146
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• 2011

The ventilation performance of a vertical exhaust duct system in the high riser public house has been evaluated by a commercial software, Fluid Flow, which solves pressure losses through the duct system including bathroom fans and a hybrid roof fan. During the numerical simulations, outdoor wind condition and stack effects in summer and winter were considered as well as the operating conditions of a basement damper and the roof fan. The results show that the bathroom ventilation in summer is the most unsatisfactory. The opening of the basement damper has a problem that the polluted air in the lower floors is exhausted to the underground parking lot, not to the rooftop. If the basement damper is closed, the exhaust flow rate in the lower floors is not sufficient due to the strong flow resistance in the long vertical duct even though the roof fan is under operating.

• 한국산학기술학회논문지
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• 제11권3호
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• pp.991-996
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• 2010

본 논문에서는 IEEE 1284 동작 모드를 사용하는 병렬 I/O 제어 시스템을 제안하고 인터넷 환경하에서 원격제어 통신을 실현하였다. IEEE 1284 표준은 다수의 특정한 동작 모드와 호환성이 있는 인터페이스를 정의하며 PC의 병렬 포트에 대해 보다 개선된 성능을 제공한다. 병렬 포트 장치는 Device/ID 식별 절차를 갖는 병렬 포트에 대해 PnP 기능을 제공하게 되는 새로운 운영체제 때문에 시스템 구성과 인터페이스 절차가 간단하게 된다. 이러한 성능 증대로 병렬 I/O 포트는 더욱 저가격, 실용이 간편한 I/O 포트로 가능하게 된다.

• 한국수학교육학회지시리즈C:초등수학교육
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• 제18권3호
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• pp.217-234
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• 2015

수학 교과에서는 컴퓨터와 인터넷 환경을 교수 학습에 적극적으로 활용해 왔다. 그러나 수학 교수 학습 웹사이트 운영의 질적인 측면에서는 여러 문제점들이 제기되어 왔다. 본 연구는 영국 케임브리지 대학교의 'Millennium Mathematics Project' 사업의 일환으로 1997년부터 운영되고 있는 NRICH 웹사이트의 운영 방식, 웹사이트 체계, 콘텐츠 내용, 콘텐츠의 연계 방식 등을 조사하였다. 이를 바탕으로 주제 중심의 콘텐츠 구성, 지속적 장기적 자료 축적, 이용자들의 참여 유도, 다양한 협력 사업 등의 측면에서 우리나라에 주는 시사점을 정리하였다.

• 대한조선학회논문집
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• 제56권2호
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• pp.135-142
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• 2019

Ice accretions on the ship equipment and areas are the most common issues for vessels operating in cold climate and ice-covered waters and it has effect on the vessel safety and operability of equipment and systems, thus ship machineries and structures exposed to low temperature environments should satisfy the winterization requirements specified in ice class rules. The main objective of this study is to review the state-of-the-art of winterization trend for vessels navigating in ice-covered waters. The hazard of icing and how ice accretions affect operations and safety are investigated firstly, and then winterized notations for each classification are summarized. In addition, winterization methods currently used in vessels operating in ice-covered waters are investigated for a better understanding of effective approach and its application. This information will provide a framework for future winterization issues to mitigate the ice accretion phenomena.

• Journal of Platform Technology
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• 제8권4호
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• pp.3-10
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• 2020

승강기 유지보수 업체는 다양한 종류의 승강기 유지 보수를 담당하고 있어 승강기 제조사, 승강기 모델에 독립적인 승강기 원격 관제 시스템이 필요하다. 이를 위해 각 승강기에서 수집된 승강기 운행 데이터를 수신하여 데이터베이스에 전송할 수 있는 데이터 수집기가 필요하다. 본 논문에서는 중소 규모의 승강기 유지 보수 업체에서 활용할 수 있는 원격 관제 시스템의 데이터 수집기를 설계, 구현한다. 데이터 수집기는 승강기의 운행 상태를 전송하는 센서 모듈이 전송한 데이터 패킷을 수신하여, 데이터를 해석, 변환한 후 자체 개발한 API 를 이용하여 서버로 전송을 한다. 본 논문에서는 파이썬으로 구현한 데이터 수집기에 대해 기술하고, 실 운행 환경에 있는 승강기에 설치된 센서 모듈에서 전송한 데이터를 수신하고, API 서버로 전송하는 것을 화면에 표시된 로그를 통해 보인다.

• 한국환경과학회지
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• 제25권11호
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• pp.1589-1595
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• 2016

From December 2014 to November 2015, an automatic weather system (AWS) was installed over a wide road of Daegu to continuously measure meteorological factors and surface temperature. We investigated the effective operating period of the clean-road system using the daily maximum and minimum air and asphalt surface temperatures, with the aim of creating an optimum thermal environment. The clean-road system was installed over a part of the broad way of Dalgubul(Dalgubul-Daero) by Daegu Metropolitan City in 2011. Until now, the clean-road system has been operated from the middle of April to the end of September. We assumed that it was desirable that the clean-road system could be operated when the discomfort index was above 55. In conformity with the conditions, we concluded that the optimum operation period of the clean-road system is from the end of March to about the middle of October.

• 근관절건강학회지
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• 제25권3호
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• pp.196-204
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• 2018

Purpose: The purpose of this study was to contribute to the activation of comprehensive nursing care services by comparing and analyzing the working environment and operational status of comprehensive nursing care wards with general wards. Methods: A questionnaire survey was conducted at hospitals operating comprehensive nursing care services. We collected data on patient characteristics, workforce, working environment, and work support facilities of 40 hospitals voluntarily participating in the survey. The collected data were analyzed by dividing it into an comprehensive nursing care ward and a general ward. Results: Compared with the general ward, the comprehensive nursing care ward had fewer hospitalized patients, but the severity of the patients and the need for nursing were high. The number of nurses, assistant nurses, and ward support workers per patient was higher in the comprehensive nursing care ward than in the general ward, and the implementation rate of night shift fixed system, the fixed shift system, and the preceptor system were higher. In terms of structural environment, comprehensive nursing care wards had more room for interviews. Conclusion: The comprehensive nursing care ward had more nursing staff and provided a better working environment than the general ward, but required additional support for the structural environment.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1589-1592
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• 1997

Among the prerequisite abilities (perception of environment, path planning and position estimation) of an autonomous mobile robot, position estimation has been seldom studied by mobile robot researchers. In most cases, conventional positioin estimation has been performed by placing landmarks or giving the entrire environmental information in advance. Unlikely to the conventional ones, the study addresses a new method that the robot itself can select distinctive features in the environment and save them as landmarks without any a priori knowledge, which can maximize the autonomous behavior of the robot. First, an orjentaion probaility model is applied to construct a lcoal map of robot's surrounding. The feature of the object in the map is then extracted and the map is saved as landmark. Also, presented is the position estimation method that utilizes the correspondence between landmarks and current local map. In dong this, the uncertainty of the robot's current positioin is estimated in order to select the corresponding landmark stored in the previous steps. The usefulness of all these approaches are illustrated with the results porduced by a real robot equipped with ultrasonic sensors.

• 한국물환경학회지
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• 제16권4호
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• pp.533-539
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• 2000

A bench-scale reactor using SBR process was experimented with an synthetic wastewater. The main purpose of this investigation was to evaluate applicability in the field and process removal efficiencies in terms of BOD and T-P and its corresponding kinetic parameters. Removal rate of phosphorus was 77% in terms of total phosphorus. Effluent concentrations were $9.8mg/{\ell}$ BOD and $1.1mg/{\ell}$ T-P. Effluent quality was maintained consistently stable by controlling decant volume and operating cycles. The efficiency for phosphorus removal was increased due to decrease in BOD-SS loading value in the range of $0.25{\leq}$aeration time ratio${\leq}0.52$.