• 제목/요약/키워드: open set

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유체기계에 있어서 부의 음원 임피던스의 원인에 관한 고찰 (A Review of the Possible Causes of Negative Source Impedance in Fluid Machines)

  • 이정권
    • 한국음향학회지
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    • 제20권3호
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    • pp.76-82
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    • 2001
  • 대부분의 유체기계는 일정 조건하에서는 주기적인 소음 원들로 간주될 수 있으며, 소음원 및 관련 덕트의 음향계를 주파수영역으로 표현이 가능하게 되는데, 음원은 주파수의 함수인 음원강도와 음원 임피던스로 표현된다. 이들 변수를 알아내기 위하여는 다양한 이론적, 실험적 방법이 있으나, 고속, 고온, 고강도의 유체 기계와 같은 단일 연결구를 갖는 음원에 대하여는 다양한 길이의 많은 관들을 부하로 사용하는 다부하법만이 적용 가능하다. 문제는 이 다부하법을 적용했을 때, 음원 임피던스의 실수부가 부의 값을 갖는 경우가 많다는 점이다. 본 논문에서는 이 문제의 명확한 원인분석을 위한 일환으로서, 다양한 이론적 실험적 결과에 대한 분석을 바탕으로 하여 가능한 여러 가지 원인에 대한 물리적 조사 결과를 보이고, 분석 결과에 대한 새로운 해석을 통해 기본 가정의 위배와 함께 다부하법 자체의 문제점을 제시한다 유체 기계 덕트에서는 다른 무엇보다도 음원의 시변성이 부의 음원저항을 낳는데 가장 큰 영향을 미치게 되며, 부하 임피던스가 최종 결과에 지대한 영향을 미치게 된다.

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O.P.E.N Triad: The Future Success for Individuals, Institutes, and Industries

  • Kim, Hae-Jung;Forney, Judith;Crowley, Ruth
    • 한국의류학회지
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    • 제34권12호
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    • pp.1980-1991
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    • 2010
  • This study proposes the O P E N Triad framework as a future set of tools and perspectives for individual members and institutes to further their professional and academic potential as well as prospect and vitalize the future of the Korean Clothing and Textiles discipline through a global perspective. The millennial generation desires On-demand, Personal, Engaging, and Networked (O P E N) experiences effecting cultural change for creative and influential interaction in transactions, communication, and education. O P E N Individuals offers a WebSphere model as a holistic learning system that has a synergizing value of education across academic courses, industries, and cultures. Through a digitalized and virtualized class, it complements relevant technologies already familiar to the student population. By employing environmental scanning approaches, the most influential and viable future global issues related to the clothing and textiles discipline are identified and dialogued within O P E N Institutes. For future clothing and textiles institutes, this scanning allows them to be open to new ideas, to focus on inter-engagements, to collaborate among individuals, to associate as a part of web of people, organizations, and ideas, to personalize an institutes curricula, and to dialogue generative knowledge. O P E N Industries reveals three dominant future issues that cross academia and industry, sustainability, supply chain management, and social networking. In-depth interviews with U.S. industry experts identified interdependent gaps in global consumer experience practices and suggested the following gaps as future research areas: a standardized business model to the entrepreneurial model, strategic management to a sustainable competitive advantage, standardized to differentiated products, services and operations, market segmentation to global consumer clusters, business-driven marketplaces to consumer-engaged marketspaces, and excellent services to optimal experience. This O P E N Triad framework empowers millennial students, universities, and industries to anticipate and prepare for a radically changing world.

새만금 방조제 개활지의 준설토 기반에 대한 배수층재 처리가 수목 생육에 미치는 효과 (Effects of Materials of Drainage Layer at the Reclaimed Soil Base on Tree Growth at the Open Space of Saemangeum Sea Dike)

  • 이한나;임주훈;구남인;배상원
    • 한국환경복원기술학회지
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    • 제18권1호
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    • pp.13-23
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    • 2015
  • This study was performed to compare the effects of different drainage layers on tree growth at the exposed sites of Saemangeum sea dike. 4 types of drainage layers including control(dredged soil), specially prepared bark, gravel, and wood chip were set in 150~165cm depth of soil. Pinus thunbergii and Celtis sinensis were planted after 9 months of soil treatment. Electrical conductivity(EC) of soil in all treated plots were decreased under $4dS{\cdot}m^{-1}$, and NaCl(%) was decreased under 0.05% after 1 year from soil treatment. Soil moisture at the 120cm depth of the bark treated plot was higher than that of the 180cm soil depth, below the drainage layer. It is considered that vertical mobility of water was inhibited. Organic matter(OM) at the 120cm soil depth increased at bark and wood chip treated plots. Survival rates after 4 years of P. thunbergii and C. sinensis were 100% in all treatments. The height of P. thunbergii was not significantly different among the treatments while the height of C. sinensis was significantly different among the treatments and it was highest at the bark treated plot.

Fresh Produce Container Operated with a Routine of Hypobaric Application, CO2 Injection and Diffusion Tube Opening for Keeping Beneficial Modified Atmosphere

  • Park, Su Yeon;An, Duck Soon;Lee, Dong Sun
    • 한국포장학회지
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    • 제26권2호
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    • pp.53-60
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    • 2020
  • A concept of household container to create and keep the modified atmosphere (MA) beneficial for fresh produce mix was devised and tested under typical chilled storage conditions of 3℃. The container system containing mixed products is initialized by applying weak hypobaric condition (0.9 atm) and subsequently injecting CO2 gas at an appropriate low level (0.03 atm). The passive atmosphere modification by produce respiration is then induced to reach a target until gas diffusion tube of proper dimension starts to open. The design was made to attain quasi-steady state mass balance of O2, CO2 and N2 to maintain the desired MA through the storage. Interrupted opening for taking out or placing some products was to reinitialize the loop of control logic. The developed concept was tested by the container which held commodities of spinach, pak choi, oyster mushroom, peeled onion, strawberry and cut carrot. The target optimum MA of 11% O2 and 10% CO2 (0.11 and 0.10 atm, respectively) was set to avoid injurious range of O2 and CO2 concentrations for any commodities. The developed container system could work to reach and maintain beneficial MA of 0.10-0.12 atm O2 and 0.07-0.10 atm CO2 close to the target during the storage contributing to quality retention of products measured in weight loss, chlorophyll content of spinach, ascorbic acid content of pak choi, color of onion, texture of oyster mushroom, bacterial count of strawberry and carotenoids of carrot. The container system shows potential to improve current preservation practice of fresh produce mix on consumers' level.

장기요양보호대상노인의 시설적응과정에 관한 근거이론적 접근 -내버려진 마음 누그러뜨리기- (Grounded Theory Approach on the Adaptation Process in Facility of Long-Term Care Elderly)

  • 신용석;김수정;김정우
    • 한국사회복지학
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    • 제65권3호
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    • pp.155-182
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    • 2013
  • 본 연구는 장기요양보호대상노인의 시설생활 적응과정은 어떠한지, 어떻게 경험하고, 어떠한 행태적 특징을 보이는지를 살펴보는데 그 목적이 있다. 노인요양시설에서 생활하는 노인 15명을 대상으로 심층면담을 한 내용을 Strauss 와 Corbin(1998)이 제시한 근거이론을 활용하여 분석하였다. 분석결과, 15개의 범주와 42개의 하위범주 그리고 170개의 개념이 추출되었다. 장기요양보호대상노인의 시설적응 과정에서 경험하는 중심현상은 '내버려짐'으로 나타났다. 이에 대한 인과적조건, 맥락적조건, 중재적조건, 작용/상호작용 전략과 결과를 통합한 핵심범주는 '받아들임'으로 구체화되었으며, 그 유형에 따라 운명-체념형, 현실-수용형, 자발적-선택형으로 구분되는 것으로 확인 하였다. 연구 결과를 바탕으로 노인을 둘러싸고 있는 상호작용요인으로써 시설환경과 종사자, 시설 내 다른 노인과의 대인관계, 가족의 지지가 강화되도록 실천적 대안을 제시하였다.

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三國遺事에 나타난 配偶者 選擇 및 性意識에 관한 연구 (A Study on Mate Selection and Sex Consciousness reflected in Samguk Yusa)

  • 백경임;김일명
    • 대한가정학회지
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    • 제37권1호
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    • pp.1-13
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    • 1999
  • The purpose of this study is to find how the mate selection and sex consciousness reflected in Samhuk Yusa. We set up the following two questions for aim of this study. First, how are the real aspects and specific characters of mate selection reflected in Samguk Yusa? Second, how are the real aspects and specific characters of sex consciousness reflected in Samguk Yusa? The results can be summarized as follows; 1. Mate selection reflected in Samguk Yusa discussed into two major domains, one is spouse conditions and the other is marriage form. Men and Women are married at teenages, but the greater part of case is unidentified, so in order to approach this we need to analyse other historical documents. In men and women, standard of appearance and personality is difference. Analyzed case about appearance is a few, also we need to analyse other historical materials. More valued personality is wisdom in men, and in women more valued personality is virtue, brightness, graceful and mild. Through in case of to overcome the cultural gabs, the society must be open in every area. The marriage form is diversity, examples, free marriage, a marriage of convenience type, etc. Especially in aspects remarriage of man and woman is free in every class. 2. Sex consciousness reflected in Samguk Yusa discussed into three major domains, first is discussion about sex, second is premarital sexual behavior, third is extramarital. Through the case of discussion about sex is opened so there is not existence double blinded in sexual norms. Also through the case of premarital sexual behavior and extramarital, fidelity ideology does not yet come into existence.

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초등학생 학교체육복 디자인 프로토타입 개발에 관한 연구 (A Study on the Development of Design Prototype for Physical Education(PE) Uniforms of Elementary School)

  • 문명옥;김은정;이진숙
    • 한국의류산업학회지
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    • 제18권5호
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    • pp.677-684
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    • 2016
  • This study was done for the proposal for improvement for junior sportswear which is substitutable as uniforms in the form of elementary school and physical education uniforms by analyzing detailed features through investigation. Accordingly, we developed a prototype design for physical education uniforms as a symbol of the school to enhance the aesthetic and functional satisfaction. The results are as follows. When we developed physical education uniforms, we put activity on our first priority while taking the improvement in both aesthetic and functional aspects into consideration. In addition, we tried to make sure the uniforms reflect the refined and trendy elements to meet students needs to satisfy their aesthetic sense in dress. Reflecting the improvement proposals and preferences of the students, six different prototype designs were developed and evaluated on the basis of two concepts of "new basic" and "trendy". The highest ranking, the physical education uniforms design 1 is based on new basic concept and characterized with slim fit considering activity which will be worn as fall/winter physical education uniforms. Design 1 uses ottoman functional knit as a fabric material which is not only students favorite but also good in both flexibility and warmth. Top with style of high-neckline collar and full open zip-up is simplified with the incision lines and detail. It is a set-in sleeve design in which blue and yellow collars signifying school color are properly placed along with the incision lines in harmony.

측추력기 Shutter의 단방향 유체-구조 연성해석에 관한 연구 (A Study on the 1-Way FSI Analysis for Shutter of Side Jet Thruster)

  • 고준복;서민교;이경호;백기봉;조승환
    • 대한기계학회논문집A
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    • 제38권12호
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    • pp.1359-1365
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    • 2014
  • 본 연구에서는 측추력기 구성품인 Shutter의 열구조 안전성을 평가하기 위해 단방향 유체-구조 연성해석을 수행하였다. Shutter는 측추력기에서 노즐을 개방시키기 위한 구동 토크와 연소가스의 고온, 고압 열하중을 받는 부품으로 연소가 진행되는 동안 열구조 안전성을 확보하여야만 한다. 유체-구조 연성해석을 위해 측추력기의 연소시간동안 내부 유동장에서 발생하는 연소가스의 압력 및 온도 분포, 대류 열전달계수값을 유동해석을 통해 도출하였고, 이 결과 값을 맵핑 방식을 이용하여 열구조 해석의 하중조건으로 부가하였다. 연소시간동안 Shutter에서 발생되는 최대 응력 및 취약위치, 온도분포를 단위 시간 단위로 분석하여 온도에 따른 소재의 인장강도 값과 비교하여 열구조 안전성을 평가 하였다. 또한 반경 방향 변형량을 분석하여 셔터와 노즐목 간의 적정 간극을 설정하는 근거로 활용하였다.

학습성과의 개념과 작성에 대한 탐구 (A Critical Evaluation of the Concept and Writing of Learning Outcomes)

  • 이동엽;양은배
    • 의학교육논단
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    • 제18권3호
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    • pp.125-131
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    • 2016
  • Recent changes in educational paradigms that emphasize the performance or outcomes of education are redefining how learning objectives are being described as 'learning outcomes' in various academic disciplines. Medical education is not an exception to this trend. However, it has come to our attention that the key concepts and appropriate descriptions of learning outcomes have not been well understood among educators and that this lack of understanding has hindered our efforts to implement the practice in the field. This study aims to provide a direction to establish and describe learning outcomes by examining previous studies that have focused on setting learning objectives as well as learning outcomes. Setting and describing learning outcomes starts from reflection on the approach of behavioral learning objectives, which overemphasizes learner's acquired knowledge, skills, and attitude in each classroom rather than actual performance. On the other hand, the learning outcome approach focuses on what the learner is able to do as a result of a learning experience. This approach is more learner-friendly and encourages students to lead and be responsible for their learning process. Learning outcomes can best be described when the relevance of actual contexts and the hierarchy of learning objectives are considered. In addition, they should be in the form of context, task, performance, and level, as well as be planned with proper assessment and feedback procedures. When these conditions are met, the learning outcome approach is beneficial to students as it presents a curriculum that is more open to learners. Despite these advantages of the learning outcome approach, there is a possible concern that setting the learning outcomes and describing them can restrict evaluation to lower cognitive skills if the concept of learning outcome is narrowly interpreted or is set too low. To avoid such narrow applications, it is important for educators to understand the comprehensiveness of the learning outcome setting and to consider long-term outcomes embedded in an organizational vision rather than only short-term behavioral outcomes.

함수 요약에 기반한 메모리 누수 정적 탐지기 (A Static Analyzer for Detecting Memory Leaks based on Procedural Summary)

  • 정영범;이광근
    • 한국정보과학회논문지:소프트웨어및응용
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    • 제36권7호
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    • pp.590-606
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    • 2009
  • C프로그램에서 발생할 수 있는 메모리 누수(memory leaks)를 실행 전에 찾아 주는 분석기를 제안한다. 이 분석기는 SPEC2000 벤치마크 프로그램과 여러 오픈 소스 프로그램들에 적용시킨 결과 다른 분석기에 비해 상대적으로 뛰어난 성능을 보여준다. 총 1,777 KLOC의 프로그램에서 332개의 메모리 누수 오류를 찾아냈으며 이 때 발생한 허위 경보(false positive)는 47개에 불과하다(12.4%의 허위 경보율). 이분석기는 초당720 LOC를 분석한다. 각각의 함수들이 하는 일을 요약하여 그 함수들이 불려지는 곳에서 사용함으로써 모든 함수에 대해 단 한번의 분석만을 실행한다. 각각의 함수 요약(procedural summary)은 잘 매개화 되어 함수가 불려질 때의 상황에 맞게 적용할 수 있다. 실제 프로그램들에 적용하고 피드백 받는 방법을 통해 함수가 하는 일중에 메모리 누수를 찾는데 효과적인 정보들만으로 추리는 과정을 거쳤다. 분석은 요약 해석(abstract interpretation)에 기반하였기 때문에 C의 여러 문법 구조와 순환 호출 (recursive call), 루프(loop)등은 고정점 연산(fixpoint iteration)을 통해 자연스럽게 해결한다.