• KIEAE Journal
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• v.17 no.1
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• pp.49-54
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• 2017

Purpose: Temperature in urban areas increase much more than suburban areas and it is called urban heat island (UHI) phenomenon. There are several solutions to control UHI phenomenon such as green roof system, water space construction, and cool roof system. However, application of green roof system and cool roof system to some of the buildings which compose the city has a critical limit. Therefore, in order to diminish the temperature rising and UHI phenomenon due to climate change of the city, it needs to approach from the viewpoint of site or city, rather than the viewpoint of individual buildings. This study is aims at analyzing UHI phenomenon by characteristics of surface materials and suggesting the solutions to reduce UHI phenomenon by types of complex. Method: Literature reviews were conducted to analyze the cause, mitigating plan, and recent trends of UHI phenomenon. For the simulation analysis, the type of complex was classified 3 representative complex. Based on measured reflectivity, simulation about UHI phenomenon was conducted by setting 4 strategies; albedo of roof, road pavement, green roof system, and vegetating around buildings. Result: As the results of simulating the UHI reduction factor by types of complex, it showed that the effect of temperature reduction on the building roof layer is more effective than adjusting the reflectivity of buildings such as green roof system, planting near the buildings in both the detached house complex, apartment complex, and commercial complex.

• Asia pacific journal of information systems
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• v.12 no.4
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• pp.173-192
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• 2002

Internet-based on-line firms have focused on the development of new business models with an assumption that this new model would create their competitiveness. At the same time, off-line firms have opened new marketing channels on the internet in order to defend their position against on-line firms. Based on Porter's well-known generic strategy, this study compares between on-line firms and on-offline firms i) whether these two types of firms take different strategies among cost reduction, marketing differentiation, innovation differentiation, and focus and ii) how the performance of these two types of firms is affected by different strategy types. The result shows that on-offline firms prefer the strategy of marketing differentiation and innovative differentiation while the strategy of cost reduction and focus are taken without significant difference between online firms and on-offline firms. Also it is found that even though the strategy of marketing differentiation and innovation differentiation are more preferred by on-offline firms than on-line firms, these two strategy types have a significant influence on the on-line firms' performance while the focus strategy has a significant influence on the on-offline firms' performance. Other managerial implications are discussed.

• Journal of the Korean Home Economics Association
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• v.36 no.12
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• pp.55-71
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• 1998

The purpose of this study was to identify the characteristics of coping behaviors of non-professional working mothers and find out the individual and situational factors which affect the degree of coping behaviors. For this research, the working mothers in non-professional job with children under age 18 answered the structured questionaire. The findings were as follows. First, the degree of coping behaviors was rather high in multiple role management strategies, strengthening family system and positive thinking, but rather low in housework socialization and role reduction/standard adjustment. Second, the effect of associated variables were different according to the subcategories of coping behaviors. So we conclude that, the coping behaviors of the non-professional working mothers were different from those of professional working mothers in some aspects, althought they have much similarities. The different aspects were 1) The relationship of family income and the degree of housework socialization was more evident. 2) The work-related variables did not affect the coping process significantly because of the conservative sex-role attitued of them. Second, non-professional working mothers should use coping behaviors such as housework socialization, role reduction/standard adjustment more for the more effective management of the role strain. Third, the attitude of occupational and parental role was one of the most important factors in using the role strain coping behaviors. And such an unconscious use of the coping behavior won't be helpful in the feeling of control over environment including role strain and active coping of working mothers.

• Journal of Information Technology Applications and Management
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• v.24 no.1
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• pp.93-110
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• 2017

This study aims at classifying and analyzing the business models of reverse overseas direct purchasing through online shopping-malls. After analyzing the current status of the reverse overseas direct purchasing online markets, this study identifies relevant critical business factors and synthesizes prior studies to construct and analyse the business models. This study proposes that the business models can be classified into five types according to the operation modes and three types according to the delivery methods. So theoretically 15 business models can be identified. For each business model this study analyzes the characteristics and the pros & cons. It also suggests deployment strategies for companies by considering cost reduction, brand establishment, customer management, customer aquisition, and easiness from the business perspective. From the customers perspective, cost reduction, reliability, royalty, ease to purchase, and accessibility can be considered according to the types of operation mode. The main contribution of this study is to provide the basic classifications and structures of reverse overseas direct purchasing business models systematically. As the result, our study evaluates the business models that which one is better than others in a situation in terms of company and customer. Lastly, we talk about limits and future prospects of the study.

• Culinary science and hospitality research
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• v.13 no.4
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• pp.232-242
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• 2007

Consumers are not simply consuming products anymore. They now take part in developing new products. Thus, it is essential that we devise a variety of consumer-oriented marketing strategies to keep close relationships with consumers. The purposes of this study were as follows: 1) to explore the relationship between customer participation and surveys on its effect, 2) to compare groups with respect to customer participation, and 3) to see whether there is a cause-effect relationship between the customer participation and surveys on its effect. Frequency analysis, correlative analysis and discriminate analysis were used to analyze the data. The results of testing hypotheses can be summarized as follows. we find that, as for customer participation factors, there is significant relationships among survey factors including customer satisfaction, cost reduction, customers' prior occupations. The current analysis exhibits favorable results in the customer participation and such factors. The analysis shows that there is significant difference between the active groups and the passive groups in all the new product development related factors; customer satisfaction, cost reduction, customers' prior occupations. Finally, this perhaps indicates that the result of the survey depends on whether firms are positive or negative in introducing customer participation.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.3007-3012
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• 2008

Multidimensional simulation has been carried out to be clear the role of initial combustion in a marine diesel engines on reduction of NOx and soot emissions by different pilot injection condition. Pilot injection can shorten the ignition delay, thus it reduces the premixed combustion phase. Since most NOx is formed during premixed combustion, pilot injections is one of reliable strategies to reduce the NOx. The formation of NOx consists of that formed by pilot injection and that formed by main injection. The result explains that 25-3-75 among the pilot injection conditions is effective to reduce the NOx, due to optimal combination pilot injection with main injection. The purpose of this study is to explain the characteristics of combustion with pilot injection of the marine diesel engine on reduction of exhaust emissions by examining the combustion process in a cylinder and to explore the formation mechanism of NOx between pilot injection and main injection.

• Proceedings of the Acoustical Society of Korea Conference
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• 1994.06a
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• pp.785-790
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• 1994

The active noise control which regards the acoustic power as a target function to be minimized, is analyzed to test its feasibility of which simplifies the measurement system compared with the global acoustic energy based active noise control system. In fact, it is found that the acoustic power based active noise control strategy is equally likely as good as the global acoustic energy based active noise control method if the acoustic field of interest is diffusive or very low model density one. In the intermediate model density field, we also demonstrate that the power based control gives the similar results as the energy based control in terms of global sound energy reduction for the lightly damped enclosure which might be most important system in practical application. From all the theoretical and power based control strategy is dependent on the characteristics of the acoustic field to be controlled; i.e., the model density distribution, the degree of reverberation, and on the strength of modal interaction of the control source with the primary source; i.e., the location of control source.

• Journal of Obesity & Metabolic Syndrome
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• v.27 no.4
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• pp.203-212
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• 2018

Dynamic energy balance can give clinicians important answers for why obesity is so resistant to control. When food intake is reduced for weight control, all components of energy expenditure change, including metabolic rate at rest (resting energy expenditure [REE]), metabolic rate of exercise, and adaptive thermogenesis. This means that a change in energy intake influences energy expenditure in a dynamic way. Mechanisms associated with reduction of total energy expenditure following weight loss are likely to be related to decreased body mass and enhanced metabolic efficiency. Reducing calorie intake results in a decrease in body weight, initially with a marked reduction in fat free mass and a decrease in REE, and this change is maintained for several years in a reduced state. Metabolic adaptation, which is not explained by changes in body composition, lasts for more than several years. These are powerful physiological adaptations that induce weight regain. To avoid a typically observed weight-loss and regain trajectory, realistic weight loss goals should be established and maintained for more than 1 year. Using a mathematical model can help clinicians formulate advice about diet control. It is important to emphasize steady efforts for several years to maintain reduced weight over efforts to lose weight. Because obesity is difficult to reverse, clinicians must prioritize obesity prevention. Obesity prevention strategies should have high feasibility, broad population reach, and relatively low cost, especially for young children who have the smallest energy gaps to change.

• Journal of Power Electronics
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• v.19 no.4
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• pp.907-921
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• 2019

This paper presents two advanced hybrid pulse-width modulation (PWM) strategies for multilevel inverters (MLIs) that provide both common-mode voltage (CMV) elimination and current ripple reduction. The first PWM utilizes sequences that apply one switching state at the double ends of a half-carrier cycle. The second PWM combines the advantages of the former and an existing four-state PWM. Analyses of the harmonic characteristics of the two groups of switching sequences based on a general switching voltage model are carried out, and algorithms to optimize the current ripple are proposed. These methods are simple and can be implemented online for general n-level inverters. Using a three-level NPC inverter and a five-level CHB inverter, good performances in terms of the root mean square current ripple are obtained with the proposed PWM schemes as indicated through improved harmonic distortion factors when compared to existing schemes in almost the entire region of the modulation index. This also leads to a significant reduction in the current total harmonic distortion. Simulation and experimental results are provided to verify the effectiveness of the proposed PWM methods.

• ETRI Journal
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• v.40 no.6
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• pp.699-713
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• 2018

Orthogonal frequency division multiplexing (OFDM) has been the overwhelmingly prevalent choice for high-data-rate systems due to its superior advantages compared with other modulation techniques. In contrast, a high peak-to-average-power ratio (PAPR) is considered the fundamental obstacle in OFDM systems since it drives the system to suffer from in-band distortion and out-of-band radiation. The partial transmit sequence (PTS) technique is viewed as one of several strategies that have been suggested to diminish the high PAPR trend. The PTS relies upon dividing an input data sequence into a number of subblocks. Hence, three common types of the subblock segmentation methods have been adopted - interleaving (IL-PTS), adjacent (Ad-PTS), and pseudorandom (PR-PTS). In this study, a new type of subblock division scheme is proposed to improve the PAPR reduction capacity with a low computational complexity. The results indicate that the proposed scheme can enhance the PAPR reduction performance better than the IL-PTS and Ad-PTS schemes. Additionally, the computational complexity of the proposed scheme is lower than that of the PR-PTS and Ad-PTS schemes.