• Wind and Structures
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• 제10권3호
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• pp.287-300
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• 2007

Wind action is a factor of fundamental importance in the structural design of light or slender constructions. Codes for structural design usually assume that the incident mean wind velocity is parallel to the ground, which constitutes a valid simplification for frequent winds caused by meteorological phenomena such as Extratropical Storms (EPS) or Tropical Storms. Wind effects due to other phenomena, such as thunderstorms, and its combination with EPS winds in so-called squall lines, are simply neglected. In this paper a model that describes the three-dimensional wind velocity field originated from a downburst in a thunderstorm (TS) is proposed. The model is based on a semi empirical representation of an axially-symmetrical flow line pattern that describes a stationary field, modulated by a function that accounts for the evolution of the wind velocity with time. The model allows the generation of a spatially and temporally variable velocity field, which also includes a fluctuating component of the velocity. All parameters employed in the model are related to meteorological variables, which are susceptible of statistical assessment. A background wind is also considered, in order to account for the translational velocity of the thunderstorm, normally due to local wind conditions. When the translation of the TS is caused by an EPS, a squall line is produced, causing the highest wind velocities associated with TS events. The resulting vertical velocity profiles were also studied and compared with existing models, such as the profiles proposed by Vicroy, et al. (1992) and Wood and Kwok (1998). The present model predicts horizontal velocity profiles that depend on the distance to the storm center, effect not considered by previous models, although the various proposals are globally compatible. The model can be applied in any region of interest, once the relevant meteorological variables are known, to simulate the excitation due to TS winds in the design of transmission lines, long-span crossings, cable-stayed bridges, towers or similar structures.

• 대한지역사회영양학회지
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• 제21권1호
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• pp.12-24
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• 2016

Objectives: The objectives of the study were to investigate the school nutrition teachers' perception on their job and to find out recommendations needed for its improvement in order to provide a quality foodservice and nutrition education at schools. Methods: A total of 219 school nutrition teachers in Seoul were surveyed using selfadministered questionnaires. Results: The perceived importance of the 16 job duties was rated 3.8 based on a 5-point scale (1: very unimportant - 5: very important). The importance of six duties including nutrition management, production management, nutrition education, and food safety management were rated over 4 point but that of record-keeping for documents, official reporting, and service management was rated the lowest. Importance-Performance Analysis showed that nutrition management, receiving/storage management, production management, menu management, food safety management, and equipment/facilities management should be emphasized to maintain the current performance of duties. The performance of the nutrition education and counseling needed to be improved since the importance scores were greater than average but the performance scores were lower than the average. Official reporting and miscellaneous jobs were rated the highest for simplification need. More than half of the respondents agreed that equipment/facilities management, miscellaneous jobs, service staff supervision, and service line supervision could be allocated to other school departments. Conclusions: School nutrition teachers should invest more time and resources on their core job duties such as nutrition management, production management, food safety management, and nutrition education for providing quality foodservice and nutrition education. To reflect the environmental changes of school foodservice, a reasonable staffing index of school nutrition teachers needs to be developed. In addition, hiring an assistant or implementing school nutrition teacher internship programs can be useful to reduce workloads of the nutrition teachers.

• 한국정보통신학회논문지
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• 제16권12호
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• pp.2747-2754
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• 2012

본 논문에서 PC 컨텐츠의 활용을 극대화시키는 부가기능을 갖는 다중 LCD(Liquid Crystal Display) 시스템을 개발하였다. 이는 host LCD와 slave LCD로 구성되어 있다. Host LCD는 NTSC(National Television System Committee), PAL(Phase Alternation Line), SECAM(S$\acute{e}$quentiel couleur avec m$\acute{e}$moire) 신호를 받아 영상 및 음성을 데코딩하여 출력한다. 이 데코딩된 신호들을 LVDS(Low Voltage Differential Signaling) 신호로 변환하여 slave LCD단으로 전송을 하는 기능을 갖는다. 그리고 CF 메모리, USB 메모리등을 장착하여 멀티미디어 데이터를 출력하도록 한다. Slave LCD는 host LCD와 달리 튜너부분이 없고 메모리 장착이 되지 않아 자체 TV 신호 수신 및 영상 신호 재생을 하지 못한다. 다만, LVDS 영상 신호를 받아 LCD 팬널에 출력하는 기능만 갖도록 한다. 본 논문에서 개발한 다중 LCD 시스템은 제품이 단순하여 상대적으로 고장률이 낮고, 가격이 저렴하고 제어부분의 간소화로 디스플레이의 전력이 낮으며, host LCD의 채널, 볼륨 및 영상 출력에 대하여 전체 slave LCD를 제어할 수 있는 제품으로서의 가격 및 기능 경쟁력을 갖추고 있다.

• 전력전자학회논문지
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• 제9권6호
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• pp.620-627
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• 2004

H-브릿지 멀티레벨 인버터는 여러 개의 단상 Power Cell을 직렬로 연결함으로써 저전압 전력용 반도체를 사용하여 고전압을 얻을 수 있고, 정현파에 가까운 출력전압 파형을 얻을 수 있는 멀티레벨 인버터 토폴로지이다. 본 논문은 산업현장에서 신뢰성을 인정받아 많이 사용되고 있는 직렬통신 방식의 일종인 CAN통신 인터럽터를 이용한 H-브릿지 멀티레벨 인버터 Power Cell의 PU 동기화 및 위상전이 방법에 관한 것이다. 제안된 방법의 주요 장점은 주제어기와 셀 제어기 사이에 직렬통신(CAN)을 사용함으로써 주제어기와 셀 제어기의 신호선의 단순화, 주제어기의 부담 감소, Power Cell의 모듈화, 셀 단위의 보호동작 용이, 확장성 향상 그리고 제어 신호 및 Power Cell의 신뢰성을 향상에 있다. 13레벨로 구성된 H-브릿지 멀티레벨 인버터 시험을 통해 제안된 방법의 타당성과 신뢰성을 입증하였다.

• 전기학회논문지
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• 제65권1호
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• pp.31-39
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• 2016

Power system engineers use power systems solution programs such as PSS/E, DSATool, Power World simulators for power system analysis. In this reason, KEPCO has begun to develop independent power system program, KW-PSS(KEPCO World Power system Solution) since 2002 and KW-PSS ver2.0 development was completed in 2011. However, it did not have much better functions compared with other programs. Therefore, we focused on the development of the practical and specialized functions. Consequently, PAZ(Power system AnalyZer) ver3.0 has been developed and it realized a differentiation than previous version. In other words, previous version focused on the basic function of power system analysis, PAZ ver3.0 has implemented many automated functions for power system operators were driven maximize operational efficiency. The unique feature of the implementation is as follows : Automated check for exceeding the breaker capacity, Scheduled outage automation, Control-file wizard for various voltage stability analysis, Scenario-based multiple transient stability analysis and Auto calculation of transmission line impedance. As shown in these functions, Those functions provide to use power system analysis easily by automation and simplification for power system engineers. We will secure national expertise through PAZ ver3.0. In addition it will be able to gain competitive edge through the steady development in the world market.

• 한국의류학회지
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• 제32권1호
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• pp.99-109
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• 2008

The purpose of this study was to survey sizing system and preferable ease and to decide the body measuring items for pattern making in a men's dress shirt for mass customization industry that is rising to the surface as a new production system. For this, it had a survey subjects were 254 males between 25 to 44 years old who wear dress shirt frequently and the relevant on line companies, and analyzed the garment sizing system and preferable ease. Collected data were analysed by frequency analysis, t-test, $X^2-test$, and ANOVA using SPSS 12.0 for window. Garment pattern making should reflect the sizes of the body parts well, and simplification of the ordering process would work as an important variable. In relation to the preferable ease, older people preferred more ease while younger people preferred fit ease. In relation to the sizes, people wearing the size of '110' preferred more ease than the size of '90'. And people weighing over 90kg preferred sufficient ease than less weighing. People height over 170cm people preferred sufficient ease for the length between shoulders than height under 170cm. In case of the companies had no consistent sizing system. Significant difference was found in the sizes, except for the size of '100', among those companies, there was significant difference in the length between shoulders and the length of the shirt among those companies and those sizes. Significant body parts for a garment pattern making was height, the circumference of the neck, the chest circumference, the length between biacromion, the arms length, and the waist circumference.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.327-332
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• 2006

In airborne gravimetry, there are two data streams. One is the specific force measured by an air/sea gravimeter or accelerometers, the other is kinematic acceleration measured by DGPS. And the difference of them provides the gravity disturbance information. To satisfy the requirement of most applications, an accuracy of 1mGal $(1mCal=10^{-5}m/s^{2})$ with a spatial resolution of 1km is the aim of current airborne gravimetry. There are two different methods to derive the kinematic acceleration. The generally used method is to differentiate the position twice, and the position can be calculated by commercial DGPS software. The main defect of this method is that integer ambiguities need to be fixed to get the precise position solution, but it's not a trivial thing for long base line. And to fix integer ambiguities, the noisier iono-free measurement is used. When differentiation is applied, noise is amplified and will influence the accuracy of acceleration. The other method is to get carrier phase acceleration by differentiate the carrier phase first, and then using the acceleration of GPS satellite to derive the vehicle acceleration. The main advantages include that fixing integer ambiguities is not needed anymore, position can be relaxed to about 10 meters, and smoother acceleration can be got since iono-free measurement is not needed. In some literatures, it's considered that the dynamic performance of the second method is inferior to that of the first. Through analysis, it is found that the performance degradation in dynamic environment results from the simplification of the GPS carrier phase observable model. And an iterative algorithm is presented to compensate the model error. Using a dynamic GPS data from an aeromagnetic survey, the importance of this compensation is showed at last.

• 한국콘텐츠학회논문지
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• 제9권6호
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• pp.357-369
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• 2009

인터넷과 정보통신기술의 발달과 보편화로 각 업계에서는 고객의 편의증진과 함께 업무자동화 및 간소화로 비용을 절감할 수 있는 기회 요인이 되고 있다. 이로 인하여 e-비지니스에 대한 관심이 점차 늘어나고 있으며 항공사는 다양한 분야의 e-서비스를 개발적용하고 있다. 전자항공권(e-ticket)은 이미 모든 항공사에서 전면적으로 실시하고 있으며, 고객이 직접 인터넷을 통한 발권 비율이 증가하고 있어 항공사는 여행사에게 지불하는 수수료를 절약하여 이를 다시 항공권 가격을 인하하거나 추가수입에 적용하고 있다. 항공사 서비스 가운데 가장 긴 시간을 할애하는 기내서비스 가운데 무선 인터넷과 통신 그리고 오락에 적용하는 e-서비스는 항공사가 타 항공사와의 경쟁력을 높이기 위하여 서비스를 개발하고 있다. 무선주파수 인식기술인 RFID는 여객운송서비스 가운데 수하물의 분실과 파손방지를 위하여 적용하고 있으며 앞으로 다양한 서비스에 적용할 것이다. 이에 본 연구는 항공사 승객이 경험한 e-서비스요인에 따른 재구매의도와 추천의사 그리고 전체만족도에 대한 영향관계를 밝혀 업계에 도움이 되는 시사점을 찾고자 하였다. 결과로 항공사의 e-서비스는 전체 만족도에 영향을 주지만 재구의도와 추천의사는 예약발권 e-서비스만이 영향을 미치는 것으로 나타났다.

• 디지털융복합연구
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• 제16권5호
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• pp.33-42
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• 2018

본 논문은 나라장터 종합쇼핑몰 개선방향에 대해 구매자 피드백(Feedback), 다양한 제품 옵션(Option) 선택 기능, 결제절차의 간소화 및 만족에 관한 선행연구의 제안을 바탕으로, 실제 나라장터 종합쇼핑몰에서 전산장비 등을 구매 및 사용하는 공공 및 산하기관 근무자들의 입장에서 개선 필요성과 만족에 대해 확인하기 위함이다. 이를 위해 기초설문과 심층 인터뷰를 바탕으로 경북지역 공공기관 및 정부산하기관에서 전산장비 등에 대해 구매경험이 있으며 실제 사용하는 전산직 및 비전산직 근무자를 대상으로 질적 사례연구를 통해 확인 하였다. 연구결과 구매자 피드백(Feedback)과 옵션(Option) 선택 부분에 대해서는 개선이 필요하다는 결론과 결제절차의 간소화와 만족에 대해서는 근무경력에 따른 차이가 있다는 것을 확인하였다. 또한 공공 및 산하기관 연구 참여자들의 사용에 대한 내면의 의견을 확인 할 수 있었던 것이 가장 큰 기여도라 하겠다. 향 후 보완사항으로, 수도권 및 타지역 공공 및 산하기관의 근무자들과 일반 조달 제품에 대한 구매경험을 가진 공공 및 산하기관 다수의 근무자들을 대상으로 한 추가연구가 필요할 것으로 보인다.

• 한국가정과교육학회지
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• 제1권1호
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• pp.53-62
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• 1989

Cooking practice is keenly related to not only the betterment of family health but to the improvement of dietary life. Cooking is a kind of practical skill and one is skill in it by repeated practice. The aim of cooking practice in school is to fix cooking method practically and scientifically, to acquire cooking skill. To achieve this aim there are many unrecognized or unsolved problems in the first-line schools. The problems and efficient ways of cooking practice in the middle and high school are as follows； 1. The aim of cooking practice： It should be first of all remembered that the practice is so practical that the knowledge and skill of cooking should be related to the future domestic life. Second, the practice should be able to serve the communal and national life by scientifying and improving life. 2. The content of the practice： First, it should be so arranged step by step that the content of each year should not be repeated. Second, the ratio of Korean cooking practice should be increased and the material of the practice should be chosen in consideration of the peculiarity of the community, seasons and economical problems so that it may be applied to the very day life. Third, to improve dietary life, the practice should be a way of the simplification of dietary life, of the nutritional efficiency. Forth, for the betterment of physical condition of the family the practice should involve balanced dietary plans and dietary therapy. 3. Teaching method： First, the practice should be scientific and comprehensive in consideration of not only cooking skills but also knowledge of nutrition. Second, micro-class system should be adopted, and practice labor should be allotted each student to develop cooperative attitude and the sense of responsibility. Third, in addition to the practice conducted in a body, comparative cooking, applicable cooking and experimental ability and the content of the text. Fourth, teachers should let the students examine and find problems by bringing them to a focus on the basis of theory. 4. Administration method： First, the practice schedule should be planned that a class has practices at least more than twice a semester. Second, two hours of class should be continued without cessation after beforehand survey and theory study. Third, facilities and utensils for practice should be enlarged. That is, cooking practice rooms, tools, utensils should be prepared. Fourth, enough cost of practice should be secured. The above mentioned points show the present situation and problems with which cooking practice teaching is confronted. In order to normalize cooking practice teaching, the first-line schools should give the above mentioned problems their careful consideration and improve the present situation so that efficient, creative, practical cooking practice will be possible.