• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.2
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• pp.153-160
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• 2002

As a way to assess the reliability of programs for building energy analysis, verification experiment and calculation of heating load are simultaneously conducted for a well-defined test space. Experimental conditions are carefully set to minimize uncertainties associated with radiation heating, air change, infiltration, and room-to-room interaction. Dyna- mic load calculations using TRNSYS, which are performed for two different computation domains, rely on the energy rate control that represents inherent load characteristics of a space. The predicted instantaneous heating load favorably simulates the overall behavior the measured one, though the latter fluctuates much more rapidly than the former Comparison of the accumulative load between the experiment and calculations shows a close agreement within an engineering tolerance, regardless of the computation model. It is deduced from such findings that the present experimental results along with weather information can serve as a set of reference data for validating load calculation softwares from the users'standpoint. In order to enhance the completeness of this work, a complementary study on the cooling load for the same test space is highly recommended.

• Journal of Electrical Engineering and Technology
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• v.5 no.2
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• pp.307-318
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• 2010

In this work, an accurate analysis of low frequency current ripple in residential fuel cell power generation systems is performed based on the proposed residential load model and its unique operation algorithm. Rather than using a constant dc voltage source, a proton exchange membrane fuel cell (PEMFC) model is implemented in this research so that a system-level analysis considering the fuel cell stack, power conditioning system (PCS), and the actual load is possible. Using the attained results, a comparative study regarding the discrepancies of low frequency current ripple between a simple resistor load and a realistic residential load is performed. The data indicate that the low frequency current ripple of the proposed residential load model is increased by more than a factor of two when compared to the low frequency current ripple of a simple resistor load under identical conditions. Theoretical analysis, simulation data, and experimental results are provided, along with a model of the load usage pattern of low frequency current ripples.

• Journal of Nutrition and Health
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• v.1 no.1
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• pp.27-31
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• 1968

The author investigated the effects of dietary composition upon the work efficiency of Splague Dowley rat at high altitude, and obtained the following results: 1. At high altitude a carbohydrate-rich diets worked more favorably upon work efficiency of the animal then a protein and or fat-rich diets did. 2. It may be recommended that fibrous components be excluded from the diets. 3. Ingestion of large amounts of sugars prior to the onset of work load is highly recommended.

• Journal of the Korean Institute of Navigation
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• v.22 no.2
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• pp.53-63
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• 1998

This study aims at suggesting a concepturla model of personnel elitism, and at evaluating the model based on a shipping company case. Specifically, it asks whether the company has met the conditions nessary for the attainment of personnel litism prescribed by the conceptural model. In order to evalutate the model, questionnaire and interview methods were adopted. The area of survey includes the quality of personnel , the efficiency level of work processes. and the level of work load. This study concludes that the rationalization of work processes and training and development of personnel are necessary for a company to realize personnel elitism.

• Korean Management Science Review
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• v.13 no.2
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• pp.25-48
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• 1996

Mixed Model Assembly Lines (MMALs) are increasingly used to produce differentiated products on a single assembly line without work-in-process storage, Usually, a typical MMAL consists of a number of (1) stations doing exactly the same operation on every job, (2) stations involving operations with different choices, and (3) stations offering operations that are not performed on every job, or that are performed on every job but with many options. For stations of the first type there is no sequencing problem at all. However, for the second type a set-up cost is incurred each time the operation switches from one choice to another. At the third type of stations, different models, requring different amounts and choices of assembly work, creates an uneven flow of work along the line and variations in the work load at these stations. When a subsequence of jobs requires more work load than the station can handle, it is necessary to help the operations at the station or to complete the work elsewhere. Therefore, a schedule which minimize the sum of set-up cost and utility work cost is desired. So this study has developed Fixed Random Ordering Rule (FROR), Fixed Ascending Ordering Rule (FAOR), Fixed Descending Ordering Rule, and Extended NHR (ENHR). ENHR is to choose optimal color ordering of each batch with NHR, and to decide job sequence of the batch with it, too. As the result of experiments, ENHR was the best heuristic algorithm. NHR is a new heuristic rule in which only the minimum addition of violations from both partial sequence and unassigned sequence at every branch could be considered. And this is a heuristic sequencing rule for the third type of stations at MMAL. This study developed one more heuristic algorithm to test the performance of NHR, which is named as Practical Heuristic Rule (PHR).

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.501-504
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• 2006

The estimation of the work of heart can be treated as one of the most important parameters for determining the amount of circulating blood needed for harmonious metabolism in the human body. By monitoring the work of heart, one can detect increased work load of heart and start the treatment at the early stage of CHF. Thus it is necessary to estimate the work of heart. The contractility of the left ventricle, the second important parameter for representing the motion of heart, can be estimated through information on the work of heart. In this study, the modified Windkessel model, which has been used for a measure of vascular hemodynamic impedance parameters, was adapted to estimate the work of heart.

• Journal of the Korea Safety Management & Science
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• v.16 no.3
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• pp.257-266
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• 2014

This study was planned to investigate the effect of the exposure to hazard factors on work environment satisfaction. Existing researches about job satisfaction have focused on the general working conditions, such as working hours, wage, human relationship, job task and so on. Korean Working Conditions Survey was used for this study because that relevant questions were included. The effect of the exposure to hazard factors on work environment satisfaction may be produced by hierarchical regression analysis because of comparison with existing model for work environment satisfaction. The exposure to hazards factors were statistically significant effect on work environment satisfaction after adjusting other confounding variables, such as gender, age, educational level, job security, work hour, work load, work autonomy, social support, etc. This study has some limitation because that KWCS was cross sectional survey. Some researches about the causal effect and its mechanism may be suggested as future study.

• Journal of the Ergonomics Society of Korea
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• v.24 no.1
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• pp.37-41
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• 2005

Work related musculoskeletal disorders became a hot issue in Korea since many workers reported musculoskeletal disorder problems. Korean government enacted a law to require companies to take measures to prevent musculoskeletal disorders at work. This study found workers' WMSDs symptoms in squatting work posture which the rate of the occurrence was relatively high among work types to bring about WMSDs in railroad cars maintenance works and analyzed to compare the hazardous jobs in the industrial safety health law in South Korea with the caution jobs in Washington State in U.S. The hazardous jobs in South Korea were more effective in squatting work posture from this study result and this study data will be a great help to plan and carry out an effective prevention program about WMSDs.

• Journal of Families and Better Life
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• v.16 no.1
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• pp.125-139
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• 1998

This study investigates work loads and coping strategies of the married female production workers(MFPW). The data of 370 MFPW in manufacturing sector in Taegu are collected by using a questionare in August 1995 The findings of this study are as follow: 1) The results of objective work loads assessed time dairy show that the average working hours is 14.25 hours during weekdays. The respondents spend 11.5 hours and 2.75 hours on doing paid and household work respectively,. The shortage of phisiological and leisure time due to spending excessively long time on work. 2) MFPW perceive the severe subjective work loads in the areas of personal family and social life. The perceived burden from paid work itself is relatively low due to the nature of their job. 3) The coping strategies MFPW actually adopted are limited mostly to those from an individual domain such as shortening the time for sleep leisure or household labor.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.288-290
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• 2006

An efficiency improving method for Uninterruptible Power Supply System(UPS) was developed by using OP-AMP based application circuits such as voltage detection device, current detection device and static switch control device. The efficiency improving algorithm was made by mixing the operating concepts of On-Line type UPS with the operating concepts of Off-Line type UPS. The UPS' inverter does not work if the UPS' output load current is not higher than the low load operating current which is about 0-30(%) of the UPS' output load capacity. The low load operating current is adjustable within the half of the UPS' output load capacity. If the UPS' output load current is rising over than the low load operating current, the UPS' inverter starts working and the inverter output power feeds to the loads of UPS. If UPS' input power breaks out while UPS' inverter does not operate because the load current is low, the inverter starts working within 4(ms) with excessive output voltage which is ${\pm}$8(%) of normal UPS' output voltage. Like these. UPS can continuously feeds power to it's load device and reduce power consumptions.