• Journal of the Korea Safety Management & Science
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• v.10 no.2
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• pp.225-235
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• 2008

It is expected that the change of industrial structure of Knowledge based economy, and service based economy would affect on economic life of physically-challenged person with no exceptions. There have been some former studies which have been misunderstood the employment of disabled due to the declining employment of the disabled and prejudice to the disabled based on biased perspective and public opinion. This study have analyzed the employment conditions of the ordinary workers and disabled workers out of those prejudices and biased opinions. Wage, economic activity ratio, age, educational background and industry those 5 parameters are brought for analyzing the two comparison group. Each parameter have compared based on the statistical data of ordinary workers and disabled workers for past 7 years. Weight between each parameter have been drawn by collecting the experts' opinion using AHP(Analytic Hierarchy Process), and utility of employment of two comparison groups have been estimated through progress inclination of each parameter. Through the estimated outcome, present condition and controversial issues and way of improvement of domestic employment of ordinary workers and the disabled is mentioned.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1050-1052
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• 2000

An investigation into power conditioners that interface with photovoltaic array and utilities has been completed. The rating for this investigation is residential system (3-5kW) that interface with a 220V single phase utility connection. As the result of this investigation. a 3kW high frequency PWM IGBT inverter feeding a high frequency isolation transformer with a sinusoidal current wave was selected. The output of the transformer rectified with a diode bridge rectifier four IGBT, used as 60Hz switched, reverse the polarity of the rectified current on every other half cycle of the utility voltage. Even though the high frequency link system used more power semiconductors, a net size, weight, and parts cost saving result compared to the other systems due to elimination of 60Hz transformer.

• Proceedings of the Safety Management and Science Conference
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• 2008.11a
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• pp.405-419
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• 2008

It is expected that the change of industrial structure of Knowledge based economy, and service based economy would affect on economic life of physically-challenged person with no exceptions. There have been some former studies which have been misunderstood the employment of disabled due to the declining employment of the disabled and prejudice to the disabled based on biased perspective and public opinion. This study have analyzed the employment conditions of the ordinary workers and disabled workers out of those prejudices and biased opinions. Wage, economic activity ratio, age, educational background and industry those 5 parameters are brought for analyzing the two comparison group. Each parameter have compared based on the statistical data of ordinary workers and disabled workers for past 7 years. Weight between each parameter have been drawn by collecting the experts' opinion using AHP(Analytic Hierarchy Process), and utility of employment of two comparison groups have been estimated through progress inclination of each parameter. Through the estimated outcome, present condition and controversial issues and way of improvement of domestic employment of ordinary workers and the disabled is mentioned.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.188-195
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• 2022

Although issuing change orders is a common practice in the construction phase of any project, non-structural utility subcontractors are struggling and seek to find a way to reduce change orders. Therefore, this paper presents the analysis results on change orders to cultivate possible suggestions and solutions on how to reduce or minimize change orders in mechanical, electrical, and plumbing (MEP) works. Change orders in non-structural utility works are analyzed based on six categories such as rerouting and change of location, changes in weight, rejected design by Office of Statewide Health Planning and Development, District Structural Engineer, or the Structural Engineer of Record, unforeseen conditions, changed equipment, and owner-initiated change. The analysis findings showed that rerouting and changing location is the most significant cause, followed by unforeseen conditions. The results not only contribute to the existing body of knowledge on change order research area, but also help MEP contractors reduce the time and cost of change orders.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.518-522
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• 2001

In recent years, natural energy has attracted growing interest because of environmental concerns. Many studies have been focused on photovoltaic power generation systems because of the ease of use in urban areas. On the conventional system, many photovoltaic modules (PV modules) are connected in series in order to obtain the sufficient DC-bus voltage for generating AC output voltage at the inverter circuit. However, the total generation power on the PV modules sometimes decreases remarkably because of the shadows that partially cover the PV modules. In order to overcome this drawback, an AC module strategy is proposed. On this system, a small power DC-AC utility interactive inverter is mounted on each PV module individually and the inverter operates so as to generate the maximum power from the corresponding PV module. This paper presents a novel flyback-type utility interactive inverter circuit suitable for AC module systems. The feature of the proposed system are, (1) small in volume and light in weight, (2) stable AC current injection, (3) enabling a small DC capacitor. The effectiveness of the proposed system is clarified through the simulation and the experiments.

• Journal of Power Electronics
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• v.2 no.3
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• pp.181-188
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• 2002

The utility interfaced sinewave modulation Inverter for the solar photovoltaic power conditioner with a high frequency transformer is presented for residential applications. As compared with the conventional full-bridge hard switching slnewave PWM inverter with a high frequency link, the simplest single-ended edge-resonant soft switching sinewave inverter with a sinewave duty cycle pulse control scheme is implemented, resulting in size and weight reduction, low cost and high efficiency This paper presents a prototype system of the sinewave zero voltage soft switching sinewave inverter for solar power conditioner, along with its operating principle and unique features. In addition to these, this paper discusses a control implementation to deliver high quality output current. Major design of each component and the power loss analysis under actual power processing is also discussed and evaluated from an experimental point of view A newly developed utility-connected sinewave power conditioning circuit which achieves 92.5% efficiency under 4kW output is demonstrated.

• Proceedings of the Korea Concrete Institute Conference
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• 1991.04a
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• pp.19-22
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• 1991

In order to the Utilization of Fly ash, The Properties of cement Mortar use of Fly ash based on Mixing rate, strength of mortar, W/C+F and quantity of Fly ash, Flow value, and unit weight are investigated. So follow result are unit weight of mortar of Fly ash is about 2014 Kg/㎥, Compressive strength of mortar is 50-404 Kg/$\textrm{cm}^2$ and beneficial reference to the utility of domestic Fly ash were obtained.

• Journal of the Korean Society of Safety
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• v.31 no.3
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• pp.143-155
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• 2016

Recently, a massive loss of life and property is occurring in Korea due to traffic accidents, with the rapid increase in cars. For improvement of traffic safety, the Korea Transportation Safety Authority intensively analyzes accident data in local governments with low traffic safety index, performs a field investigation to extract problems and offers local governments improvements for problems, by conducting the 'Special Survey of Actual Conditions of Traffic Safety' each year, starting 2008. But local governments cannot strongly push forward the improvement projects due to the limited budget and the uncertainty of the improvement plan effects. Therefore, this study suggested a model which applied the Utility concept to the AHP theory, in order to efficiently decide a priority of the improvement plans in accident black spots in consideration of the limited budget of local governments. The number of accidents in each spot for improvement and accident severity, traffic volume, pedestrian volume, the improvement project cost and the accident reduction effect were chosen as evaluation factors for deciding a priority, and data about the improvement plan costs and the accident reduction effects, traffic accidents and traffic volume in the spots to undergo the special research on the real condition of traffic accident in the past were collected from the existing studies. Then, regression analysis was carried out and the Utility Curve of each evaluation factor was computed. Based on the AHP analysis findings, this study devised a priority decision method which calculated the weight and the utility function of each evaluation factor and compared the total utility values. The AHP analysis findings showed that among the evaluation factors, accident severity had the biggest importance and it was followed by the improvement plan cost, the number of accidents, the improvement effect, traffic volume and pedestrian volume. The calculated utility function shows a rise in utility, as the variables of the 5 evaluation factors; the number of accidents, accident severity, the improvement plan effect, traffic volume and pedestrian volume increase and a fall in utility, as the variables of the improvement plan cost increase, since the improvement plan cost is included in the budget spent by a local government.

• Journal of the Korea Convergence Society
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• v.7 no.5
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• pp.181-188
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• 2016

This study investigated consumer convergence preferences for healthcare information service in social media using the multi-attribute utility theory. The multi-attribute utility theory is an approach for compositional modeling attributes wherein researchers compute the overall service utility by aggregating the evaluation results for attribute values. We found that healthcare information service consumers in social media evaluate the service preference through the multi attributes - Update, Cost, Usefulness, Usability, Reliability. And the study shows that individual preference by estimating weight of each attribute in the services influences the service use intention. So we believe that estimating preferences with multi-attribute utility theory will predict business success of the services in a new media, and for a successful business of the social media services marketers should assess the consumer's preference using the multi-attributes.

• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.5
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• pp.477-488
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• 2024

The Korean government amended the Facilities Safety Act in 2018 to establish a performance-based maintenance system. This system is designed to comprehensively evaluate the safety, durability, and usage performance of facilities required to maintain their function in use, and to establish corresponding maintenance plans. However, the current maintenance system of utility tunnels is managed by a safety-oriented evaluation method, which has limitations in conducting performance evaluations that consider durability and usage performance. Therefore, in this study, safety, durability, and usage performance items for utility tunnels were selected using the Delphi method, and the weight of each item was calculated using the entropy weighting method. The results of this study are expected to be used in future performance evaluations of utility tunnels to support rational decision making when establishing maintenance plans.