• Title/Summary/Keyword: 혼합 감도 문제

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Dynamic Positioning Control System for Gas & Oil Exploration Platforms Using H$\infty$ Control (H$\infty$ 제어를 이용한 가스 및 석유 탐사용 플랫폼의 동위치 제어)

  • Yoo Hui Ryong;Rho Yong Woo;Park Dae Jin;Koo Sung Ja;Park Seoung Soo;Kim Sang Bong
    • Journal of the Korean Institute of Gas
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    • v.3 no.2 s.7
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    • pp.62-69
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    • 1999
  • This paper presents a design method of dynamic positioning control system(DPS) for floating Platform with rotatable and retractable thrusters using H$\infty$ servo control design method. The norm band of uncertainty is captured by multiplicative perturbation between nominal model and reduced order model. A controller robust to the uncertainty is designed applying H$\infty$ synthesis. The control law satisfying robust stability and nominal performance condition is determined through the mixed sensitivity approach. The control algorithm was evaluated on the basis of computer simulation for a proposed DPS design method and experiments was carried out with an image processing method for measurement of DPS position in a water tank The results of overall experiments show that proposed control method will be good to keep at a specified position. And they are compared with the experimental results by LQG synthesis and H$\infty$ optimal control design method.

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Change of Ink Absorption Characteristics of Ink-Jet Printing Paper with Polymeric Binder (바인더용 고분자 첨가제에 따른 잉크젯 인화지의 잉크흡수 특성변화)

  • Kim, Chul-Yong;Lee, Myung-Cheon
    • Polymer(Korea)
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    • v.30 no.6
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    • pp.550-555
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    • 2006
  • The coating material for the ink-jet printing paper tends to be waterbase as the waterbase ink-jet ink is used more widely. Waterbase coating material consists of alumina sol as a pigment, poly(vinyl alcohol) as a main binder and polymeric additive for improving properties. In this study, polymeric auditive was synthesized by combining one or toto monomers among methacrylic acid, acrylic acid and acrylamide to the basic monomers, styrene and n-butylacrylate. The properties of printability such as ink absorption, ink spreading, and optical density, glossiness and water resistance were investigated by changing the kinds of surfactants, the composition of monomers and the structure of polymer particles. Results showed that materials containing anionic surfactant and/or acrylic acid had problems in com-patibility with alumina sol. Also, coating materials containing acrylamide had good printability and lout glossiness while those containing methacrylic acid did not have good printability and high glossiness.

A Study on the Control of Parallel-Type Inverted Pendulum by $H_\infty$ Control ($H_\infty$제어에 의한 병렬형 도립진자의 제어에 관한 연구)

  • Yang, Joo-Ho;Byun, Jung-Hoan
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.31 no.2
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    • pp.178-189
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    • 1995
  • In this pater, authors derive the state - space equiation about the patallel - type inverted pendulum which is adopted as control object, and constitute the control system by $H_\infty$control theory. The modeling error is unavoidably existed by linearization error, and so on. We regard this modeling error which is determined from the identification through frequency response as unstructured model uncertainty. An augmented state - space equiation with frequency weighting function is constructed for application of the $H_\infty$theory, and the mixed sensitivity problem is considered. The weighting functions are determined in consideration of the model uncertainty and the response of system in frequency region. The $H_\infty$controller is designed by using software package for controller design. From results of response simulation, the control system designed with $H_\infty$theory guarantees low sensitivity for disturbance as well as robustness against the model uncertainties.

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University Students' Perceptions for Preparation for Multicultural Society (다문화사회 준비를 위한 대학생들의 인식)

  • Yang, Hye-Jin
    • The Journal of the Convergence on Culture Technology
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    • v.7 no.1
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    • pp.42-48
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    • 2021
  • This study was attempted to examine our perceptions, which are required as our society prepares for a multicultural society, targeting college students who are in charge of the future of a multicultural society, and to propose specific ways of changing what and how. A survey was conducted on college students taking the same liberal arts course four times each semester in 2018 and 2019, and a total of 299 survey data were used to analyze the results, excluding 6 insufficient surveys. As a result of the analysis, it was found that migrants had a negative image when they were younger or had no foreign experience. Regarding the factors of cognition of migrants, social distancing and cognitive flexibility were found to be more intimate with migrants when they were older, but were more concerned about social issues. Finally, in terms of the conditions for accreditation of migrants to Koreans, it can be seen that social welfare majors agree with the conditions for recognizing migrants as Koreans in much more categories than those with mixed majors. Based on these results, several practical methods that can be applied to college students who need to prepare to lead a multicultural society were proposed.

THE CLINICAL APPLICATION OF BUCCAL ACRYLIC APPLIANCES (Buccal acrylic appliance의 임상적 적용)

  • Noh, Hong-Seok;Kim, Shin;Jeong, Tae-Sung
    • Journal of the korean academy of Pediatric Dentistry
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    • v.34 no.2
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    • pp.315-321
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    • 2007
  • Removable appliance has many utilities in pediatric dentistry in the fields of space maintainance or occlusal guidance. In contrast to maxilla, many problems have occurred with mandible in using removable appliance such as deteriorated retention, inconvenience and patient's unwillingness to wear. It is probably due to adapting several retentive clasps at buccal side of the tooth, where there is actually little or no undercut especially in young children having the erupting teeth Moreover, acrylic base plate of conventional removable appliance is located at lingual parts, which leads to the conflict with alveolar crest undercut and sublingual soft tissues. Moreover, young children frequently do not follow the dentist's direction to elevate tongue properly during the impression taking process. Throughout this study, the position of clasps and acrylic baseplate was changed opposite to the traditional Hawley acrylic appliance in order to make a buccal acrylic appliance with buccal base plate and lingual clasp into primary dentition and early mixed dentition. This study was performed for the purpose of evaluating the buccal acrylic appliance in regards of patient compliance, retention and efficiency compared with traditional lingual acrylic appliance along with its merits and demerits. Buccal and lingual acrylic appliance were applied to 5 cases respectively which required space maintaining and tooth movement, and drew a comparison in relevance to patients' compliance, combination with the tongue's function and clinical effectiveness. According to this study, in every case buccal appliance was proved superior to lingual appliance in terms of retention and patients' compliance. Moreover, buccal appliance has shown to be similar to lingual appliance with respect to clinical effectiveness. Throughout this study, it was thought that, if removable appliance is to be applied to mandible, several drawbacks related to conventional lingual appliance shall be resolved. Conclusively, the buccal acrylic appliance is thought to be a good alternative in designing a mandibular appliance in young children and recommended to clinical applications.

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Shape Design Optimization of Crack Propagation Problems Using Meshfree Methods (무요소법을 이용한 균열진전 문제의 형상 최적설계)

  • Kim, Jae-Hyun;Ha, Seung-Hyun;Cho, Seonho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.27 no.5
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    • pp.337-343
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    • 2014
  • This paper presents a continuum-based shape design sensitivity analysis(DSA) method for crack propagation problems using a reproducing kernel method(RKM), which facilitates the remeshing problem required for finite element analysis(FEA) and provides the higher order shape functions by increasing the continuity of the kernel functions. A linear elasticity is considered to obtain the required stress field around the crack tip for the evaluation of J-integral. The sensitivity of displacement field and stress intensity factor(SIF) with respect to shape design variables are derived using a material derivative approach. For efficient computation of design sensitivity, an adjoint variable method is employed tather than the direct differentiation method. Through numerical examples, The mesh-free and the DSA methods show excellent agreement with finite difference results. The DSA results are further extended to a shape optimization of crack propagation problems to control the propagation path.

당류산업

  • 임재각
    • Food Industry
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    • s.181
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    • pp.38-67
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    • 2004
  • 예로부터 인간은 단맛에 강한 욕구를 가지고 있었다. 따라서 설탕, 포도당, 과당 등 단맛이 강한 감미료를 선호하여 왔고, 현재까지도 식품 제조시 가장 널리 사용되고 있다. 그러나 최근에는 국민의 건강에 대한 관심이 고조 되고 설탕으로 대표되는 전통적인 일반 감미료의 충치, 비만, 당뇨병 유발 등의 부정적인 측면이 부각되고 있을 뿐만 아니라, 식품에 대한 건강 기능성이 강조되면서 기능성 감미료가 주목 받고 있다. 특히 고도의 경제성장 및 국민 소득의 향상에 따라 차별화된 기능성 감미료의 생산을 요구하는 실정이다. 이와 관련하여, 현재 식품 산업계에서는 올리고당류, 당알콜류, 고감미 감미료류 등에 많은 관심을 가지고 연구 개발에 집중하고 있다. 올리고당류의 대표적인 제품은 프락토올리고당, 갈락토올리고당, 이소말토올리고당 등이다. 현재 올리고단 시장은 성숙기로서 성장속도가 둔화되고 있으나, 최근 American Association of Cereal Chemists(AACC)등 세계적인 협회에서 수용성 식이섬유를 다당류, 올리고당, 리그닌 등을 포함하여 새롭게 정의하였고 이에 따라 해외에서는 프락토올리고당을 중심으로 수용성 식이섬유로 용도 사용이 가능하게 되었을 뿐만 아니라, 식이섬유로 표기도 가능하게 되어 수요가 증가할 것으로 예상된다. 국내에서는 아직 올리고당을 식이섬유로 사용하지는 못하고 있으나, 식품 공전 개정을 통해 식이섬유로 표기 가능하도록 수정될 전망이다. 당알콜류는 솔비톨 및 자일리톨이 주류를 이루고 있다. 솔비톨은 시장에 가장 먼저 소개된 당알콜류인데 저가여서 그동안 가장 큰 시장을 형성하고 있었으나 최근 3년 동안 자일리톨껌이 최대의 히트 상품이 되면서 자일리톨이 급성장하였다. 그 외에는 만니톨, 에리스리톨, 말티톨, 이소말트 등이 있다. 최근에는 말티톨을 중심으로 다양한 응용 연구 및 이소말트 및 에리스리톨 등을 생산 판매하고 있는 다국적 기업의 판촉 활동 등으로 당알콜류 시장의 새로운 변화가 예상된다. 고감미 감미료류는 스테비오사이드와 아스파탐이 주류를 이루고 있었지만, 최근 아세설팜 K 및 수크랄로스가 잇따라 식품으로써 사용 허가를 받으면서 시장이 재편되고 있다. 하지만, 해외에 비하여 국내의 고감미 감미료 시장은 매우 작고 성장률도 낮은 편인데 그 이유로는 국민 정서상 천연이 아닌 합성에 대한 부정적 인식과 맛에 대한 거부감 때문인 것으로 생각된다. 이와 관련하여 최근에는 다양한 감미질 및 Multi sweetener system 연구를 통해 설탕과 유사한 맛을 내는 혼합 기술 개발에 관한 연구가 진행되고 있다. 따라서 향후에는 해외의 선진국과 같이 고감미 감미료 시장도 점차적으로 확대될 것으로 예상된다. 기타 대체 감미료로는 타가토스, 트레할로스, 아라비노스 등이 있다. 이중에서 특히 해외에서 크게 기대를 모으고 있는 타가토스는 최근 국내 인증을 받아 시장 진출을 준비 중에 있다. 아라비노스는 양질의 감미를 갖는 천연 펜토오스인데 연구용 시약 이외에는 지금까지 거의 이용되지 않았다. 그러나 최근 아라비노스가 설탕의 소화흡수를 선택적으로 억제한다는 흥미 있는 결과가 임상 및 동물실험에서 확인되어 향후 제품으로써 개발을 기대할 수 있게 되었다. 이들 감미료는 기존 설탕이 가지는 문제점을 많은 부분 극복할 것으로 여겨지며, 이로 인해 수요는 점차 증가할 것으로 생각되며, 높은 경제적 부가 가치를 창출할 것으로 예상되어 진다. 생산 기술 적인 측면에서 건강 지향적 천연소재 감미료에 대한 선호가 날로 증가하는 추세에 따라 기존에 주로 사용되었던 화학합성법보다는 천연 이미지의 생물공학적인 방법에 의한 감미료 생산이 각광을 받을 것으로 예상된다. 생물공학적인 방법을 감미료 소재 개발에 응용하게 되면, 기존에 사용되었던 화학합성법 등이 가지는 환경적인 문제, 반응 부산물 생성에 따른 분리, 정제에서의 비용증가 등의 문제점을 해결할 수 있을 것으로 여겨지며, 고정화 방법의 도입 등을 통해 생산성 향상을 도모할 수 있다. 본 장에서는 감미료 소재 개발에 건강 지향적 국민 정서를 반영하고, 국내외 감미료 시장의 흐름을 파악하여 당류 산업의 발전적인 변화에 대처하고자 하였으며, 이를 통해 당류산업의 고부가가치 첨단산업으로서의 육성방안을 논의하고자 하였다.

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The effects of group coaching program based on self-affirmation theory to improve undergraduate students' career exploration (진로탐색행동 개선을 위한 자기가치확인 기반 그룹코칭 프로그램 개발 및 효과성 검증)

  • Young-Mi Kwon;Myeon Soo Kim;Joung-Soon Ryong
    • The Korean Journal of Coaching Psychology
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    • v.7 no.2
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    • pp.21-46
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    • 2023
  • The current study aimed to develop and evaluate the effectiveness of a group coaching program to improve college students' career exploration behaviors based on the self-affirmation theory. Participants were undergraduate students at a University in Seoul and volunteered in the program during the break. The group coaching program was conducted twice a week during three weeks, a total of six times, and each session lasted 2 to 2.5 hours. In this study, the effect of self-affirmation embedded in the group coaching program on various psychological variables and college students' career exploration behaviors were examined. A mixed-randomized analysis was conducted to compare the pre, post, and follow-up tests of the experimental, comparison, and no-treatment control groups, each consisting of 18 participants. The results showed that participants in the experimental group coaching condition showed more significant improvements in psychological resources, career self-efficacy, openness, problem-focused coping, and career exploration behaviors compared to the comparison and control groups, and these results were maintained even after the program ended. The implications of this study for coaching theory and practice, as well as limitations and future research directions, were discussed.

Processing of a Good Quality Salted and Semi-dried Mackerel by High Osmotic Pressure Resin Dehydration under Cold Condition (저온삼투압탈수법(低溫渗透壓脫水法)에 의한 고품질(高品質)의 반염건(半鹽乾)고등어 제조(製造))

  • Lee, Jung-Suck;Joo, Dong-Sik;Kim, Jin-Soo;Cho, Soon-Yeong;Lee, Eung-Ho
    • Korean Journal of Food Science and Technology
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    • v.25 no.5
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    • pp.468-474
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    • 1993
  • A dehydrating sheet comprises polymeric water absorber. which are packed in a semipermeable cellophane film bag allowing selective permeation of water. This sheet dehydration is quite different from conventional drying method such as sun drying, hot-air blast drying and cold air blast drying in a sense that samples are dried without heat treatment. As a part of the studies to develope a new processing method for effective utilization of dark muscle fishes, the preparation of a good quality salted and semi-dried mackerel by the dehydrating sheet was attempted. The dehydration time for preparation of a salted and semi-dried mackerels containing approximately equal moisture content were revealed $180{\sim}510min$ in conventional drying method and $90{\sim}160min$ in this sheet dehydration, respectively. The moisture and histamine contents of those salted and semi-dried mackerels were $59.4{\sim}62.4%$ and $2.5{\sim}3.6 mg/100g$, respectively. The changes in peroxide value, fatty acid composition, brown pigment formation, myofibrillar protein solubility and Ca-ATPase activity during processing of the salted and semi-dried mackerel prepared by the sheet dehydration were more lower than those of products prepared by conventional drying methods. Therefore, these result showed that the quality of a salted and semi-dried mackerel prepared by the sheet dehydration was imperial to that of those products by conventional drying method.

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District 9 : Science Fiction as Social Critique (<디스트릭트 9> 사회비평으로서의 공상과학)

  • Cho, Peggy C.
    • Cross-Cultural Studies
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    • v.42
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    • pp.505-524
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    • 2016
  • This study examines the ways District 9, a film released in 2009, reworks the sci-fi genre to explore the human encounter with "other" alien populations. Like Avatar, released in the same year, District 9 addresses the tropes of conflict over land and human-alien hybridity and introduces non-humans and aliens, not as invaders, but as objects of human oppression and cruelty. Unlike many other science fiction films where the encounter between humans and non-humans occurs in an unidentifiable future time and location, District 9 crosses genre barriers to engage with urban realism, producing a social critique of contemporary urban population problems. The arrival of aliens in District 9 occurs as part of the recorded human past and the film's action is carried out in the present time in the specifically identified city of Johannesburg. A distinctly anti-Hollywood film that locates the action at the street level, District 9 plays out human anxieties about contact with others by referencing the divisions and conflicts historically attached to South Africa's sprawling metropolis and its current problems of urban poverty and illegal immigrants. Focusing on how this particular urban setting frames the film, the study investigates the ways Blomkamp's sci-fi film about extra-terrestrials presents a curious postcolonial mix of aliens and immigrants surviving in abject conditions in an urban slum and forces a realistic examination of the contemporary social problems faced by South Africa's largest city and by extension other major global cities. The paper also examines the film's representation of the human-alien hybrid and its potential as a force to resist human exploitation of the other. It also claims that though the setting is highly local, District 9 speaks to a wider global audience by making obvious the exploitative practices of profit-seeking multinationals. A sci-fi film that is keen on making a social commentary on urban population conflicts, District 9 resonates with the wider sense of insecurity and fear of others that form the horizon of the uncertain and potentially violent contemporary human world.