• 천문학회지
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• 제51권4호
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• pp.119-127
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• 2018

We examine whether the solar eclipse effect is dependent on the geographic conditions under which the geomagnetic field variations are recorded. We concentrate our attention on the dependence of the solar eclipse effect on a number of factors, including, the magnitude of a solar eclipse (defined as the fraction of the angular diameter of the Sun being eclipsed), the magnetic latitude of the observatory, the duration of the observed solar eclipse at the given geomagnetic observatory, and the location of the geomagnetic observatory in the path of the Moon's shadow. We analyze an average of the 207 geomagnetic field variation data sets observed by 100 INTERMAGNET geomagnetic nodes, during the period from 1991 to 2016. As a result, it is demonstrated that (1) the solar eclipse effect on the geomagnetic field, i.e., an increase in the Y component and decreases in the X, Z and F componenets, becomes more distinct as the magnitude of solar eclipse increases, (2) the solar eclipse effect is most conspicuous when the modulus of the magnetic latitude is between $30^{\circ}$ and $50^{\circ}$, (3) the more slowly Moon's shadow passes the geomagnetic observatory, the more clear the solar eclipse effect, (4) the geomagnetic observatory located in the latter half of the path of Moon's shadow with respect to the position of the greatest eclipse is likely to observe a more clear signal. Finally, we conclude by stressing the importance of our findings.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2335-2343
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• 2018

This paper proposes an optimal damping control algorithm of the DTI (Direct Two-level Inverter) to miniaturize and reduce the weight of auxiliary power supply for railway vehicles. The conventional auxiliary power supply for railway vehicles uses a DC-DC converter to maintain the inverter input power from the line voltage smoothly. The proposed topology does not use a DC-DC converter for reducing of manufacturing and maintenance costs. It also proposes a DTI topology removed damping resistors that generate ground signal noise in a certain period. At this time, a resonance phenomenon of DC-link voltage occurs due to variation of the inductive load, and a method of controlling the resonance phenomenon of DC-link voltage is required. In order to suppress the resonance phenomenon of the DC-link voltage, at a point before resonance occurs, this paper introduces an algorithm to suppress the resonance phenomenon of DC-link voltage by compensating the resonance component of the q axis voltage of the synchronous reference frame. The proposed algorithm verifies the effect through simulation and experiment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권4호
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• pp.1529-1547
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• 2015

Establishment of trust is important in wireless sensor networks for security enhancement and successful collaboration. Basically, a node establishes trust with other nodes by estimating a trust value based on monitored behavior of the other nodes. Since a malicious/misbehaving node might launch different attack strategies and might demonstrate random misbehavior, a trust estimation method should be robust against such attacks and misbehavior. Otherwise, the operation of trust establishment will be meaningless, and performance of an application that runs on top of trust establishment will degrade. In this paper, we propose a robust and novel trust estimation method. Unlike traditional trust estimation methods, we consider not only the weight of misbehavior but also the frequency of misbehavior. The frequency-of-misbehavior component explicitly demonstrates how frequently a node misbehaves during a certain observed time period, and it tracks the behavior of nodes more efficiently, which is a main factor in deriving an accurate trust value. In addition, the weight of misbehavior is comprehensively measured to mitigate the effect of an on-off attack. Frequency and weight of misbehavior are comprehensively combined to obtain the trust value. Evaluation results show that the proposed method outperforms other trust estimation methods under different attacks and types of misbehavior.

• 대한안전경영과학회지
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• 제18권1호
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• pp.35-43
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• 2016

The past five years, industrial accidents due to food processing machinery have been occurred 725 cases, injury by the food cutter occurred 390 cases in its. On this study, to prevent food cutter injury, an attempt is made to present the improved documentation of fundamental safety of the food cutter workplace through the injury analysis of food cutter injury and surveys on band saw machine business field. Analyzing the result of 390 cases on food cutter injury, amputation, cut, puncture occupied 75.1 percent (293 cases), compressed occupied 23.3% (91 cases), also it showed constant component without reference to gender, age, scale of work place, service period. In the survey, lack of concentration for workers have been pointed out as the biggest factor in the cause of band saw machine injury. Meanwhile, such as the EU and Japan, whereas presents safety standards about band saw machines that are tailored to each country, on the other hand, South Korea doesn't provide the standards. To prevent the food cutter injury, safety standards need to be established in consideration of amputation, cut, puncture, compressed injury and financial support is required to procure protective equipment at each place of business.

• 간호행정학회지
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• 제3권1호
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• pp.17-35
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• 1997

The purpose of this study was to identify the formation and changing pattern of nursing perspectives of nursing students. 176 subjects were composed of 118 nusing students and 58 non-nursing students. The data were collected through openended question and structured questionair. The result were as follows : 1. Nursing perspectives were classified six categories(nature of nursing, image of nursing, component of nursing, meaning of nursing, range of nursing, function of nursing) 2. As increased major lecture period, the item of ${\lceil}$Nursing is helping${\rfloor}$ was changing positively. 3. As incresed clinical practice, the student's perception about items of ${\lceil}$Nursing has gap between theory and practice${\rfloor}$, ${\lceil}$Nursing is helping${\rfloor}$ was increased. 4. As increased self-concept, the students were considered the item of ${\lceil}$Nursing is action that giving knowledge and helping to effective coping for individual and group${\rfloor}$ significantly. 5. 1) The students having religion were considered the item of ${\lceil}$Nursing must doing politely${\rfloor}$ significantly relatively to the students don't have religion. 2) The students having experience of admission to hospital in their or their family had negative nursing perspectives. 3) Against the students who select nursing major for his high school perfoermonce and advice of their significant others, the students who select nursing major for service had positive nursing perspectives.

• 한국환경과학회지
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• 제15권9호
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• pp.865-870
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• 2006

Recently, Total Organic Carbon (TOC) which can be measured instantly can be used as an organic pollutant index instead of BOD or COD due to the diversity of pollutants and non-degradable problem. The primary purpose of the present study is to reveal the properties of time series data for TOC which have been measured by real-time monitoring in Juam Lake and, in particularly, to understand the long- and short-term characteristics with the extraction of the respective components based on the different return periods. For the purpose, we proposed Discrete Wavelet Transform (DWT) as the methodology. The results from the DWT showed that the different components according to the respective periodicities could be extracted from the time series data for TOC and the variation of each component with respect to time could emerge from the return periods and the respective energy ratios of the decomposed components against the raw data.

• 복식
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• 제64권6호
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• pp.131-147
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• 2014

Purpose of this study is to analyze the meaning of the hybrid digital culture and to find out the features of digital fashion shows appearing in the period of the hybrid digital culture as there have been almost no studies on the hybrid cultural values in the fashion shows and on the diachronic socio-cultural viewpoint of fashion show. The characteristics of hybrid digital culture were identified through the analysis of cases, and they were organized into three for this study; 'non-economic creativity', 'interactive communication' and 'transcendence'. Based on these characteristics, the features of hybrid digital cultures in the modern digital fashion shows were classified into the digitalization of presentation form and the acceptance by audience of digitalization using case studies. The features of digital fashion shows which appear through the presentation form in the digital fashion shows are as follows; 'Expansion of presentation media of runway' and 'Destruction of component factors of runway'. The features of digital fashion show in the perspective of audience's acceptance of digitalization are as follows; 'Audience's field experience through the live video', 'Participation by audience in interactive manner' and, 'Immersion in the virtual reality by the audiences'.

• 대기
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• 제26권3호
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• pp.461-471
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• 2016

A quality check algorithm for the Weather Information Service Engine pulsed Doppler wind lidar is developed from a view point of spatial and temporal consistencies of observed wind speed. Threshold values for quality check are determined by statistical analysis on the standard deviation of 3-component of wind speed obtained by a wind lidar, and the vertical gradient of horizontal wind speed obtained by a radiosonde system. The algorithm includes carrier-to-noise ratio (CNR) check, data availability check, and vertical gradient of horizontal wind speed check. That is, data sets whose CNR is less than -29 dB, data availability is less than 90%, or vertical gradient of horizontal wind speed is less than $-0.028s^{-1}$ or larger than $0.032s^{-1}$ are classified as 'doubtful', and flagged. The developed quality check algorithm is applied to data obtained at Bucheon station for the period from 1 to 30 September 2015. It is found that the number of 'doubtful' data shows maxima around 2000 m high, but the ratio of 'doubtful' to height-total data increases with increasing height due to atmospheric boundary height, cloud, or rainfall, etc. It is also found that the quality check by data availability is more effective than those by carrier to noise ratio or vertical gradient of horizontal wind speed to remove an erroneous noise data.

• 가족자원경영과 정책
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• 제15권1호
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• pp.71-91
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• 2011

This qualitative case study examines how mid-life housewives perceive age, react to aging, and experience the changing of their appearance that comes with age. The participants of this study were eight housewives four full-time housewives and four working housewives in middle adulthood. This study was conducted through in-depth interviews that were based on an unstructured questionnaire, and the data was collected from January 2010 to October 2010. Findings are as follows: during mid-life, housewives continue to exert efforts toward self-development, and toward self-actualization that can unleash the potential of their "multi-self". The housewives of the Entering Middle Adulthood self-actualization period believe that the material self as manifested in appearance is the most important component of the multi-self. Indeed, both groups of housewives thought a great deal about the criterion of appearance for their age and were concerned about others' viewpoints, social stereotypes, the appearance "norm," and other characteristics related to appearance. The full-time housewives made efforts to improve their social selves, and the working housewives tried to enhance their spiritual selves. The viewpoints of husbands are often internalized into housewives' internal points of view; therefore the relationships of housewives with their husbands were crucial both to the confidence the women felt in their appearance, and to their satisfaction in life.

• 유통과학연구
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• 제11권4호
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• pp.5-11
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• 2013

Purpose - The aim of this work is to study the reorientation that the export industrial sectors in Costa Rica have experienced during the last 20 years. Research design, data, methodology - The study employs the Cluster Analysis with the export data (20 years of cut-off period) from Costa Rica to the U.S-market. To make the predictions, the technique of the time series was used, with official data (from 2001 to 2010) from the U.S. Department of Commerce and the U.S. International Trade Commission. Results - The Cluster Analysis, show how the economic sectors of traditional products exports of Costa Rica have progressively become in exporters of non-traditional products, meanwhile,the time series confirms that this trend will continue, at least during the next five years. Conclusions - The industry of traditional products exports of Costa Rica (dressmaking, vegetables, coffee, mate, species, etc.) will progressively become in exporters of non- traditional products with a high-tech component (i.e., mechanical equipment and devices, electronic devices and medical equipment),as a consequence of the Chinese (Costa Rica's main competitor) economy's presence in the Organization for Economic Co-operation and Development (OCDE). This fact has enabled the potential improvement of Costa Rica's international competitiveness in the U.S. market.