• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.8
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• pp.1360-1365
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• 2010

In this paper, we propose a distance relaying algorithm using a Discrete Fourier Transform (DFT)-based modified phasor estimation method to eliminate the adverse influence of exponentially decaying DC offsets. Most distance relays are based on estimating phasors of the voltage and current signals. A DFT is generally used to calculate the phasor of the fundamental frequency component in digital protective relays. However, the output of the DFT contains an error due to exponentially decaying DC offsets. For this reason, distance relays have a tendency to over-reach or under-reach in the presence of DC offset components in a fault current. Therefore, the decaying DC components should be taken into consideration when calculating the phasor of the fundamental frequency component of a relaying signal. The error due to DC offsets in a DFT is calculated and eliminated using the outputs of an even-sample-set DFT and an odd-sample-set DFT, so that the phasor of the fundamental component can be accurately estimated. The performance of the proposed algorithm is evaluated for a-phase to ground faults on a 345 kV, 50 km, simple overhead transmission line. The Electromagnetic Transient Program (EMTP) is used to generate fault signals. The evaluation results indicate that adopting the proposed algorithm in distance relays can effectively suppress the adverse influence of DC offsets.

• Korean Institute of Interior Design Journal
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• v.27 no.1
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• pp.88-96
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• 2018

The income level of people in South Korea has risen as the gross national income per capita reached the milestone of 30,000 dollars. More and more consumers try to change their houses according to their tastes just like they express themselves through clothes, bags, and other fashion items, thus pursuing value-based consumption. The changes to the housing culture including the greater percentage of one- or two-person households and the growing trend of lease and monthly rent have made consumers increase their demands for products to express their lifestyles. As a result, global lifestyle shops with characteristic and diverse concepts entered the South Korean market and were joined by South Korean fashion brands, large-sized stores, department stores, and fancy stationery manufacturers, which launched their own brands, in the expansion of lifestyle shops across the nation. Lifestyle shops have a couple of unique attributes including the relatively clear selection of target consumers and a clear set of VMD strategies accordingly. Based on a judgment that there was cost differentiation among brands, the investigator categorized the comparison and analysis criteria into high, middle, and low prices to apply case analysis. This study set out to analyze VMD strategies for spatial composition through cost differentiation among lifestyle shops, take the results into total consideration, and propose an effective and competitive VMD strategy for lifestyle shops through spatial composition elements.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.1
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• pp.11-22
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• 2016

Clock skew scheduling is one of the essential steps to be carefully performed during the design process. This work addresses the clock skew optimization problem integrated with the consideration of the inter-dependent relation between the setup and hold times, and clock to-Q delay of flip-flops, so that the time margin is more accurately and reliably set aside over that of the previous methods, which have never taken the integrated problem into account. Precisely, based on an accurate flexible model of setup time, hold time, and clock-to-Q delay, we propose a stepwise clock skew scheduling technique in which at each iteration, the worst slack of setup and hold times is systematically and incrementally relaxed to maximally extend the time margin. The effectiveness of the proposed method is shown through experiments with benchmark circuits, demonstrating that our method relaxes the worst slack of circuits, so that the clock period ($T_{clk}$) is shortened by 4.2% on average, namely the clock speed is improved from 369 MHz~2.23 GHz to 385 MHz~2.33 GHz with no time violation. In addition, it reduces the total numbers of setup and hold time violations by 27.7%, 9.5%, and 6.7% when the clock periods are set to 95%, 90%, and 85% of the value of Tclk, respectively.

• Journal of the Korean Society of Costume
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• v.59 no.4
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• pp.143-154
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• 2009

The purpose of this research is to investigate elderly, middle-aged female consumers' design and material preferences for lounge wear and after understanding senescent women's propensity to purchase lounge wear. The subject of research were to those living in the Seoul and capital region and 612, which did not comprise missing values, were collected and used for data analyses. All the age groups including those in their 50s and 60s prefer jacket and pants styles the most and these styles are the most favored as lounge wear as well. Those in their 50s and 60s prefer a round neckline the most while those in their 70s favor a V neckline the most. Analyses of sleeve styles of senescent women show that all the age groups favor a straight set, or a sleeve design, the most. Although the aged people investigated in this research have relatively high purchasing power, it is found that they tend to buy low priced lounge wears. Reviewing all of the above-mentioned results, the prices of garments for senescent people will be set in consideration of their economic level, so that good quality commodities may be produced and sold at different prices.

• The Korean Journal of Financial Management
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• v.1 no.1
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• pp.1-27
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• 1985

One of the most important research works in modern business enterpise is the relation between the purpose of business enterprise and decision making behavior of manager. It is because the coincidence of the former and the latter is considered an ideal type in evaluating the result of business management. Here I have set up assumptions in order to solve the above statements: (1) What purpose does the modern business enterprise set up and what kind of economic background does it have? (2) What is the theory of maximization of stock value among the purposes of business enterprise? (3) What kind of decision making do we do in the maximization of stock value in busiess administration? (4) How is the behavior of business financial manager's intention and decision made? The result pursued under the above assumptions shows that business manager's behavior of decision making is affected according to the degree that he gets some information, but basically is determined in consideration of his autonomous standpoint, namely the stability of business enterprise and the stability of manager himself while he faithfully performs his duty which is entrusted by stockholders. Therefore we come to the conclusion that there is a little gap between a manager's behavior of decision-making and the purpose of stock value maximization.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.4
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• pp.221-226
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• 2004

Power system has recently used Double-circuit Line and Multi-circuit Line in the industrial development. This has an advantage of system stability and reliability, but the complexity of the system has a disadvantage that makes it difficult to protect the power line. Double-circuit Line has two operation conditions in the Single-circuit operation and Double-circuit operation, so it has mutual impedance. To make it possible for the remaining single-line to operate independently while there is a fault with first line or when maintenance is needed, a trip region for the single-circuit operation should be set in order to set the relay trip region. An optimal trip region for each operation, a different operational conditions for the relay setting should be calculated. In this paper, trip regions of each operation condition have been compared by considering mutual impedance and fault resistance that led to the calculation of fault impedance. Also, as we know that one of the advantages in the distance relay is the back-up protection, we calculated the trip region(Zone-2) in consideration of the mutual impedance.

• The Mathematical Education
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• v.54 no.3
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• pp.261-282
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• 2015

The purpose of this study was to provide insights on making Korean mathematics framework by analytical comparison of three major assessments such as the NAEP 2015, the TIMSS 2015 and the PISA 2015. This study focused on the key differences and common themes of mathematics frameworks among three major assessments. In order to achieve this purpose, mathematical frameworks of the NAEP 2015, the TIMSS 2015, and the PISA 2015 were analyzed and compared. The criteria of the comparison were content domain and cognitive domain. The comparing criteria of content domain were based on NCTM content standards and cognitive domain were used the three understanding levels of Jan de Lange's pyramid model. Based on these comparisons, researchers discussed that Korea mathematical framework was needed to have a set of content categories that reflect the range of underlying mathematical phenomena and a set of cognitive levels which contain the range of underlying fundamental mathematical capabilities including consideration of contexts.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.4
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• pp.221-221
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• 2004

Power system has recently used Double-circuit Line and Multi-circuit Line in the industrial development. This has an advantage of system stability and reliability, but the complexity of the system has a disadvantage that makes it difficult to protect the power line. Double-circuit Line has two operation conditions in the Single-circuit operation and Double-circuit operation, so it has mutual impedance. To make it possible for the remaining single-line to operate independently while there is a fault with first line or when maintenance is needed, a trip region for the single-circuit operation should be set in order to set the relay trip region. An optimal trip region for each operation, a different operational conditions for the relay setting should be calculated. In this paper, trip regions of each operation condition have been compared by considering mutual impedance and fault resistance that led to the calculation of fault impedance. Also, as we know that one of the advantages in the distance relay is the back-up protection, we calculated the trip region(Zone-2) in consideration of the mutual impedance.

• Spatial Information Research
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• v.7 no.2
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• pp.223-236
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• 1999

Recently, the need of wast incineratory has been recognized. However, the waste incinerator is considered the typical example of NYMB syndrome as a locally unwanted facilities. Therefore, the site selection of waste incineratory should be determined very carefully with consideration of various location factors. The purpose of this study is to provide a new decision-making process model for site selection that provides a rational and a systematic way. The fuzzy set theory and AHP theory, which have merits to overcome uncertainly and complexity of spatial data, are applied to select candidate sites for the waste incineratory. The method is able to produce a more flexible and objective solution for selecting suitability sites in comparison to rigid boolean logic. The result of this study shows that geographic information systems have clear implication for informing the spatial decision making process.

• Journal of agricultural medicine and community health
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• v.6 no.1
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• pp.44-60
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• 1981

In Korea, the position of health among the sectors of everyday life lies behind the others. The inhabitants don't consider health so important and immediate as food and shelter. Primarily, it seemed more important for them to eat something and to educate their children than to secure health. Under this situations we must take into consideration their health status and health problems in terms of the social system. Health cannot be maintaned by itself. It inter acts with a set of social conditions such as income, knowledge about health, health institution, health insurance, social class, culture and etc. But the community health projects which have carried out in Korea since the beginning of 1970s focused mainly on the medical care and medical delivery itself regardless the background of health care. According to the existing results of socio-epidemiological and medico-sociological researches, a set of social conditions has a great effect on the inhabitants' health status and health care. So, such conditions will be considered primarily in Korea University Health Project. This paper is prepared as a preliminary step for such a program. In this paper we mainly inquired into the relationship between health and the attitudes of inhabitants.