• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.7
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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.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.2
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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.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.3
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• pp.991-996
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• 2010

In this paper, we designed a parallel I/O control system using IEEE 1284 operating modes and implemented remote control communication under the internet environment. The IEEE 1284 standard defines an interface compatible with several distinct operation modes and brings higher performance to the PC parallel port. Therefore, parallel port devices become easier to configure and simplify interface because new operating systems bring PnP function to the parallel port with the Device/ID identification sequence. With these enhancements, the parallel port become an even better low-cost, readily available I/O port on the PC.

• Education of Primary School Mathematics
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• v.18 no.3
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• pp.217-234
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• 2015

Computer technology and internet environment have been adapted to teaching and learning in Korean educational context. However, there are several problematic areas in operating web site for teaching and learning mathematics. This study aims to investigate the operating system, such as designing web site, contents information, and contents connection of NRICH web site that has been operated as a part of 'Millennium Mathematics Project' of Cambridge University since 1997. Based on these categories, this study also gives the implications for how to develop theme-centered contents, accumulation of continuous and long-term data, induction of user's participation, and various cooperation project.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.2
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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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• v.8 no.4
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• pp.3-10
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• 2020

An elevator maintenance company maintains many types of elevators from many manufactures. So, they want to use manufacture- or type-independent elevator remote monitoring system. To do this, data logger, that receives elevator operating state data from sensor module installed in elevator and transfers the data to database, is required. In this paper, we design and implement data logger of elevator remote monitoring system for providing elevator operation state information to elevator maintenance company. Data logger receives elevator operation state data from sensor module installed in elevator, decodes data, and converts to API data for transferring elevator operation state data to server. In this paper, we describe the implementation of data logger using python, and show that our implementation of data logger is successfully operating in a real elevator operating environment via log message displayed at screen.

• Journal of Environmental Science International
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• v.25 no.11
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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.

• Journal of muscle and joint health
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• v.25 no.3
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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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• 1997.10a
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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.

• Journal of Korean Society on Water Environment
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• v.16 no.4
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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${\leq}0.52$.