• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.11
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• pp.982-993
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• 2000

This paper describes an optimal control scheduling of an encapsulated ice storage system with a chiller of nominal chiller 34RT(103,200kcal/hr) and an ice storage tank of 170RT-hrs(514,080 kcal). The optimization technique used in the study is dynamic programing. The objective function is summed cost during a day including charge and discharge periods. Control strategies being used commercially are chiller priority and storage priority control. In chiller priority control, the chiller is allowed to run at full capacity during the day, subject to limitations of the building load, and the ice is only melted when and if the load exceeds the chillers full capacity. In contrast to chiller priority control, the aim in storage priority control is to melt as much as ice as possible during the day time period. The system simulation calculates the operation costs for the three control strategies in the condition of the same cooling load and the same ice storage system. The simulation period is a day, assuming that initially the tank is stored fully and the cooling load is perfectly predicted for the scheduling. Also Final state of the tank is to be charged fully.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.1
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• pp.62-71
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• 2008

Recently, the expansion of housing developments has reduced green areas in cities. The reduction of green areas caused many negative effects on human beings. For functional improvement of ecosystem, government focuses on artificial ground greening because it gives improving microclimate and saving energy consumption. This research aims to develop the system to support decision making of greening for artificial ground greening. This system consist of rooftop greening, wall greening, and street greening system which can suggest proper type of greening and calculate the effect of the greening considering the proponents inputs. It presents social, economic, and ecological value such as cost, energy saving, and temperature reduction. As it is web-based system users can easily access with internet. This system provides automatic selection modes.As a result, with this developed web-based system, decision makers can evaluate the effect of artificial ground green easily and the support to such movement will increase.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.503-507
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• 2015

Sustainability continues to gain traction in all industry sectors as people become aware of the advantages of green products. The voluntary use of green products in buildings in the United States continues to grow due to long-term cost saving and the ecological benefit to nature. The voluntary installation of green products is associated with end-users' expectations and perceptions including cost saving, sustainable behavior, and social responsibility. Although involuntary use of green products has similar expectations and perceptions, the installation decision is not based on the goodwill from end-users. This paper surveys college students to capture current experience levels, expectations, and perceptions in regard to green products and/or sustainability and to understand their attitudes about involuntary use of a green product. The installation of low water pressure showerheads in a dormitory provides data to support perception, expectation, and future direction of adoption of green products in public buildings. This information may be used to facilitate sustainable behaviors among involuntary groups regarding to the adoption of green products. The primary objective of this paper is to investigate the college students' perception of a green product, particularly when the students are involuntarily exposed to the green products. As a secondary objective, the paper also attempts to address the college students' general understanding on sustainability and green products. The findings of this study could support the growing importance of sustainable behavior among higher education beyond social responsibility and provide a benchmark against which to improve future change while fostering sustainable behaviors over time among the public.

• Journal of KIBIM
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• v.7 no.3
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• pp.11-20
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• 2017

BIM technology, which is widely used in the construction industry, has been introduced in various fields for the purpose of saving construction cost and reducing construction schedule. However, in the case of BIM-based cost estimate, there are various trials and errors in applying BIM technology which can be applied for calculating quantity and cost estimate. BIM-based cost estimate can improve the quantity accuracy and allow to easy modifications that were not expected in 2D-based construction process. However, for this purpose, it is necessary to take into consideration that interoperability between BIM data and cost information should be planed in advance. Besides, the definition of a BIM data specification is also required for the seamless data exchange and integrity in each phase of the construction process. Therefore, in this study, we propose a BIM - based cost estimation method and technology in each type of work applicable to the current domestic construction industry.

• KIEAE Journal
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• v.6 no.1
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• pp.3-10
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• 2006

As has been expected, economic factors are a major consideration in almost every decision in building design process. Assuming that improving a lighting system, existing or proposed, will reduce operating cost, what preliminary economic guidelines can be established to determine whether any proposed investment appears cost effective? In such a case a reasonable technique to compare system costs is by life-cycle costing. Stated simply, a life-cycle cost represents the total cost of a system over its entire life cycle, that is, the sum of first cost and all future costs. This paper aims to exemplify the benefit of daylighting in term of economic consideration. Four different electric lighting system designs are proposed and a lighting control system that is continuously operating according to the level of daylight in the space has been adapted. The accumulated performance of electric and daylighting is figured out to declare the effective depth of daylight in the space. The analysis on the saving amount of lighting energy due to daylight has been undertaken in answer to the question, that is, several projects are being considered, which is the most desirable from the cost-effectiveness viewpoint. The result shows clearly that although denser layout of lighting fixtures might be more effective to interface to the level of daylight ceaselessly changeable, its economic benefit may not meet the expected criterion the reason of increased initial investment and maintenance cost for the fixtures and control hardware.

• Journal of Broadcast Engineering
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• v.23 no.6
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• pp.836-854
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• 2018

This study is analyzing the effects of energy conservation consciousness on Korean energy saving behavior through the mediating effects of energy-related broadcasting media, such as TV. The study is carried out through the survey with structured questionnaire for each factors, using a mediating analysis based on PROCESS Macro proposed by Hayes (2013). The results of the study have been found that people with higher energy conservation consciousness displayed energy saving behavior more frequently and more actively for energy saving behavior as they were more exposed to energy-related broadcasting media. By energy-related broadcasting media the effect of energy public service ad and campaign was the largest at 15.3%, followed by energy news at 12.1%. But energy documentary has no effect on energy saving behavior. Based on the results of this analysis, it is necessary to establish a broadcasting policy that enhances the frequency of energy-related broadcasting media and energy documentary that can induce energy saving behavior. It is also necessary to make efforts to increase the reliability of analysis through empirical data such as electricity bills and fuel cost which show the actual saving level by energy saving behavior.

• Journal of KIISE
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• v.41 no.10
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• pp.745-761
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• 2014

To address the problems of existing traffic information acquisition systems such as high cost and low scalability, wireless sensor networks (WSN)-based traffic information acquisition systems have been studied. WSN-based systems have many benefits including high scalability and low maintenance cost. Recently, various sensors are studied for traffic surveillance based on WSN, such as magnetic, acoustic, and accelerometer sensors. However, ultrasonic sensor based systems have not been studied. There are many issues for WSN-based systems, such as battery driven operation and low computing power. Thus, power saving methods and specific algorithms with low complexity are necessary. In this paper, we introduce optimal methodologies for power saving of ultrasonic sensors based on the modeling and analysis in detail. Moreover, a new vehicle detection algorithm for low complexity using ultrasonic data is presented. The proposed methodologies are implemented in a tiny microprocessor. The evaluation results show that our algorithm has high detection accuracy.

• Journal of the military operations research society of Korea
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• v.35 no.2
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• pp.99-117
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• 2009

Energy is essential factor of production for a firm to produce goods and services. If so, what is the condition of maintaining profit of a firm when energy price is going up? In conclusion, the condition is that the rate of productivity improvement should be greater than the rate of energy price increase. To put this concretely, when the elasticity of energy price as to the productivity improvement is greater than the weight of the energy cost on to the total revenue of the firm, the firm can escape the negative effect of energy price increase. This is that, saying that once more, the firm have to reduce the energy cost or promote energy efficiency to maintain appropriate or sufficient profit when energy price is going up fast. Therefore, in this study we will analyze the effect of the oil price increase on the energy saving investment and that of energy saving investment on the energy efficiency in the field of Korean manufacturing industry. In doing so, this study could show that the effect of energy price increase on the energy efficiency of the firm and the factor of that mechanism.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.203-205
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• 2006

This paper presents a novel soft-switching PWM utility frequency AC to high frequency AC power conversion circuit incorporating boost-half-bridge inverter topology, which is more suitable and acceptable for cost effective consumer induction heating applications. The operating principle and the operation modes are presented using the switching mode and the operating voltage and current waveforms. The performances of this high-frequency inverter using the latest IGBTs are illustrated, which includes high frequency power regulation and actual efficiency characteristics based on zero voltage soft switching (ZVS) operation ranges and the power dissipation as compared with those of the previously developed high-frequency inverter. In addition, a dual mode control scheme of this high frequency inverter based on asymmetrical pulse width modulation (PWM) and pulse density modulation (PDM) control scheme is discussed in this paper in order to extend the soft switching operation ranges and to improve the power conversion efficiency at the low power settings. The power converter practical effectiveness is substantially proved based on experimental results from practical design example.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.387-390
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• 2006

This paper presents a novel soft-switching PWM utility frequency AC to high frequency AC power conversion circuit Incorporating boost-half-bridge inverter topology, which is more suitable and acceptable for cost effective consumer induction heating applications. The operating principle and the operation modes are presented using the switching mode and the operating voltage and current waveforms. The performances of this high-frequency inverter using the latest IGBTs are illustrated, which includes high frequency power regulation and actual efficiency characteristics based on zero voltage soft switching (ZVS) operation ranges and the power dissipation as compared with those of the previously developed high-frequency inverter. In addition, a dual mode control scheme of this high frequency inverter based on asymmetrical pulse width modulation (PWM) and pulse density modulation (PDM) control scheme is discussed in this paper in order to extend the soft switching operation ranges and to improve the power conversion efficiency at the low power settings. The power converter practical effectiveness is substantially proved based on experimental results from practical design example.