• 제목/요약/키워드: Flexible Shape

검색결과 445건 처리시간 0.024초

흉요추용 척추경 나사못시스템의 기계적 특성 (Mechanical Characterization of the Pedicle Screw System for Thoracolumbar Spine)

  • 이효재;최화순;안면환;송정일
    • 대한의용생체공학회:의공학회지
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    • 제23권1호
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    • pp.17-26
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    • 2002
  • 본 연구의 목적은 척추 내고정 시스템인 척추경 나사못의 기계적 특성 평가를 통하여 내고정 시스템에 영향을 미치는 주요 하중요소를 규명하고. 하중요소에 대한 정하중 평가와 단분절 시스템(one bevel system)에서의 피로수명을 증가시키는 방법을 제안하는 것이다. 정하중 시험에서 단일 척추경 나사못(single pedicle strew)에 작용하는 하중요소는 마찰력((friction force), 굽힘력(bending force), 결합력(holding force)으로 나타났으며, 단일 나사못의 굽힘력 시험결과로부터 단분절 시스템에 대한 시험결과의 유추가 가능하였다 척추 내고정 시스템의 상부 부분 시험의 피로수명 보다는 봉(rod)의 유연성을 포함하는 단분절 시스템에서의 피로수명이 길게 나타났고. 인체에 삽입되는 척추경 나사못 단분절 시스템에서 근육 및 ligament 등에 의해서 봉의 유연성 저하를 가져올 수 있음을 고려할 때. 단일 나사못 피로시험만으로 단분절 시스템의 피로수명 예측이 가능함을 보였다.

3차원 광학 측정을 위한 디지털 프린지 투사에 있어서 LCD 비선형 감마 에러 개선 방법 (An Improved Method of LCD Gamma-nonlinearity Error Reduction in Digital Fringe Projection for Optical Three-dimensional Shape Measurement)

  • 김우성
    • 한국광학회지
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    • 제31권3호
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    • pp.134-141
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    • 2020
  • 디지털 프린지 투사를 이용한 3차원 광학 측정시스템은 많은 비접촉 측정 응용에 사용된다. 수 ㎛까지 측정할 수 있는 이 시스템은 LCD를 사용하여 디지털 프린지 패턴을 생성한다. 이는 다양한 디지털 프린지 패턴을 컴퓨터 소프트웨어로 쉽게 만들 수 있기 때문이다. LCD 감마비선형에 의하여 물체에 투사된 디지털 프린지 패턴 에러는 3차원 물체 측정의 정확도에 영향을 준다. 정확도를 개선하기 위하여 광도전달함수(intensity transfer function)의 역함수를 사용하여 LCD 감마비선형에 의한 에러를 줄일 수 있는 개선된 방법을 제안하였다. 표준 반도체시편을 가지고 컴퓨터에서 생성한 사인파와 카메라에서 얻은 사인파의 차를 측정하여 제안한 방법의 개선효과를 보였다.

DESIGN OF A LOAD FOLLOWING CONTROLLER FOR APR+ NUCLEAR PLANTS

  • Lee, Sim-Won;Kim, Jae-Hwan;Na, Man-Gyun;Kim, Dong-Su;Yu, Keuk-Jong;Kim, Han-Gon
    • Nuclear Engineering and Technology
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    • 제44권4호
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    • pp.369-378
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    • 2012
  • A load-following operation in APR+ nuclear plants is necessary to reduce the need to adjust the boric acid concentration and to efficiently control the control rods for flexible operation. In particular, a disproportion in the axial flux distribution, which is normally caused by a load-following operation in a reactor core, causes xenon oscillation because the absorption cross-section of xenon is extremely large and its effects in a reactor are delayed by the iodine precursor. A model predictive control (MPC) method was used to design an automatic load-following controller for the integrated thermal power level and axial shape index (ASI) control for APR+ nuclear plants. Some tracking controllers employ the current tracking command only. On the other hand, the MPC can achieve better tracking performance because it considers future commands in addition to the current tracking command. The basic concept of the MPC is to solve an optimization problem for generating finite future control inputs at the current time and to implement as the current control input only the first control input among the solutions of the finite time steps. At the next time step, the procedure to solve the optimization problem is then repeated. The support vector regression (SVR) model that is used widely for function approximation problems is used to predict the future outputs based on previous inputs and outputs. In addition, a genetic algorithm is employed to minimize the objective function of a MPC control algorithm with multiple constraints. The power level and ASI are controlled by regulating the control banks and part-strength control banks together with an automatic adjustment of the boric acid concentration. The 3-dimensional MASTER code, which models APR+ nuclear plants, is interfaced to the proposed controller to confirm the performance of the controlling reactor power level and ASI. Numerical simulations showed that the proposed controller exhibits very fast tracking responses.

개별화학습지원-학습객체모델에 기초한 교수설계모형 개발 (The Development of Instructional Design Model, based on LO-Model supporting Individualized Learning)

  • 홍지영;송기상;이태욱
    • 컴퓨터교육학회논문지
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    • 제6권4호
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    • pp.115-123
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    • 2003
  • 일반적인 코스웨어에서는 단순한 분기 수준에서 학습자료를 제시하는 것 이외의 개별화에 관한 노력을 찾아보기 힘들다. 이러한 문제의 원인은 다양한 측면에서 찾아볼 수 있지만, 코스웨어 자체가 융통적이지 못하고 재사용이 불가능한 하나의 고정된 구조로 구성되어 있으며 개발하는 데 있어 많은 비용과 시간이 소모된다는 것이다. 소프트웨어 개발 방법에서 객체지향개념이 등장한 것과 같은 맥락으로 코스와 컨텐트 개발에서는 학습객체라고 하는 개념이 대두되어 이를 통한 융통적인 코스 설계의 가능성을 보여주고 있다. 하지만 학습객체 기반의 코스 설계에서도 여전히 기존의 코스웨어와 비슷한 형태와 구조를 보이고 있으며, 학습객체를 활용한 개별화학습 구현에 대한 노력은 아직 미비하다. 본 연구에서는 기존 학습객체를 확장하여 개별화학습을 지원할 수 있는 개략적인 개별화학습지원-학습객체모델을 제안하며, 이를 기초로 개별화된 학습경로를 제시해 줄 수 있는 교수설계모형을 ADDIE 모델을 기초로 설계해 보았다.

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일식메뉴 해설에 관한 연구 I (A study on Interpretating Japanese Menus)

  • 송청락
    • 한국조리학회지
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    • 제4권
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    • pp.211-224
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    • 1998
  • This study is research about coinage and interpretation of Japanese Menus in luxury hotels in Seoul. Japanese Menus consist of three categories. These can be expressed A+B+C groupings. A represents Ingredients, C represents the cooking method, while B shows the name of a region(B1), the seasoning(B2), and a word that expresses the shape of the food(B3), etc. B can be flexible in meaning. However, the setting, A+B+C, is not always used strictly for these category meanings. Ingredients, A, is sometimes used independently(ex, ぃくとろろ), and at other times B1 + C, B2 + C or B3 + C are used. Sometimes A+C is used without B. The most general expression is Ingredients + the method for cooking(A+C Type). By knowing the menu description the food type and cooking method can be discovered. Most concrete method is Ingredients + procedure for seasoning + cooking method(A+B2+C Type) show how something is made and what kind of seasoning. This method is frequently used for roasted dishes with seasoning. Food which is expressed by A, Ingredients, does not require a complicated cooking process and is fixed by a conventional cooking process without any explanation ; delicacies(珍味), an hors d'oeuvres(前菜), sushi(Japanese vinegared rice delicacies) and sliced raw fish. There are two obstacles in interpreting Japanese Menus. First, we cannot look up the menu words easily in a dictionary because the mixing of Chinese Characters and the pronunciation of them differs from Korean chinese characters. Secondly, the names of Japanese food are inserted with a name of a place or another symbolic word, so they sometimes cannot be translated. We should offer various and accurate information for foreign customers because various Non-Japanese people use these restaurants frequently. This will enable them to enjoy themselves more comfortably. Therefore, you should decide the words carefully and provide an explanation about the complicated parts of the Menu when you work with Menu copywriter.

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모듈러 건축의 현황과 활용에 관한 기초연구 - 사례조사 분석을 중심으로 - (A Basic Study on the Application of Modular Construction - Focused on the Analysis of Case Study -)

  • 김재영;이종국
    • 한국주거학회논문집
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    • 제25권4호
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    • pp.39-46
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    • 2014
  • This research was for the investigation and analysis of the illustration of modular construction application which is different use by each school facility since modular construction related examples are rare in domestic situation, and it has a limitation because of its being basic research material for generating the basic form of modular construction. The research results are as followings. First, in case of school facility from illustration investigation results, module measurement of class modulation is as similar as $3m{\times}10m$, but in resident facility the planning of more flexible plane shape can be possible since modules of 6 cases are free and various, and facade form of various types can be appeared by combination of module unit. Second, as a result of the generated characteristics in compared analysis of representative examples, school facilities were highly indicated for movability and duration reduction areas, and the flexibility, economic efficiency, and environment-friendliness was indicated low relatively. Third, the basic planning types of modular construction can be largely divided into layered type, horizontal (straightway) type, and compound type. The layered type has a short traffic line and facility system and is appropriate for the low-rise form unless separate construction method is used since it is susceptible to load. The horizontal type is advantageous for securing an opening since it has wide extent in light but has a long traffic line and facility system. Finally, the compound type can be possible for planning of various forms but needs the combination of various unit modules and traffic line and facility plan for it can be difficult.

접선 지정법을 이용한 대화형 G$^1$스플라인 (Interactive G$^1$ Splines with Tangent Specification Method)

  • 주우석;박경희;이희승
    • 한국정보처리학회논문지
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    • 제1권4호
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    • pp.531-540
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    • 1994
  • 스플라인 함수는 결과적으로 생성되는 커프모양에 의해 캐드 상에서 물체의 외형 을 설계할 수 있게 하는 가장 기본적인 도구이고, 따라서 새롭게 효율적인 커프 모양 의 개발은 산업 설계 분야 전반에 직접적인야 영향을 줄 수 있다. 본 논문은 더욱 다 양하고 자유로운 커브 모양을 만들기 위하여 시각적으로 연속인 부류의 스플라인 함 수를 그리기 위한 도구를 설계하고 구현한다. 이 부류의 스플라인은 기존 스플라인에 비해 자유자재의 다양한 모양을 생성함과 동시에 일반적인 카디날 스플라인이 갖는 보간성을 아울러 갖고 있다는 점이다. 본 논문의 가장 큰 중요성은 매개변수의 스칼라 수치값을 제시하던 기존 G$^1$ 커브 구현방식에서 벗어나, 사용자가 시각적인 벡터를 사 용하여 접선의 모양을 지정케하고 그 결과를 커브 생성을 위한 매개변수로 변형시킬 수 있는 공식을 유도하고 구현한 점이다. 생성된 결과 커브자체가 원래 지정된 접선 에 충실하게 되므로, 캐드 사용자의 입장에서는 설계하고자하는 커브의 개형을 시각화 시킨 접선의 모양에만 치중할 수 있는, 단순한 인터페이스가 가능하게 된다. 따라서, 설계자의 입장에서는 본 논문에 구현된 스플라인 도구를 사용한다면 마우스와 같은 간 단한 입력장비만으로도 다양하고 효과적인 커브 모양을 생산할 수 있다.

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한복 전시를 위한 마네킹에 관한 연구 (A Study on the Mannequins for the Display of Hanbok)

  • 김여경;김정민;홍나영
    • 복식
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    • 제63권6호
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    • pp.113-126
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    • 2013
  • The purpose of this study is to analyze the current use of mannequins that are designed to display Hanbok and put forward suggestions for improvement. In order to carry out the study, an analysis on the mannequins that are currently in the market was conducted along with a survey with professionals who are in charge of the display. The significance of the study is that it has gathered the opinions of professionals who are currently participating in the displays of Hanbok to lay the foundation for improvements. As Hanbok is a flat-pattern costume unlike the Western ones, the most prominent way to display is to lay them on the floor or hang them on the wall. Nevertheless, the mannequin displays are needed to show the beauty of Hanbok as the silhouette can only be completed when it is put on a body. A new type of mannequins that can portray the distinctive features of Korean beauty more effectively need to be developed. Although the museum and enterprise slightly differ in their preferences and requirements for the mannequins, both agree on the following criteria; the shape should be adjusted: the protruding breasts of the mannequin are not suitable for Hanbok, the body should be disassembled: all parts of the body should be separable and it should be flexible at the joints so that it can produce various poses, the face should represent the "koreaness" and the material should be soft. Based on these findings, we put forth the suggestion that a more suitable mannequin should be developed to portray the beauty of Hanbok.

롤 형상 필름 생산에서 두께평활도 개선을 위한 고정굴곡부 발현 모형 및 개선 모델 (A Model for Detection and Refinement of Fixed Bending Regions for Improving the Degree of Thickness Uniformity in Rolled Film Manufacturing)

  • 배재호
    • 산업경영시스템학회지
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    • 제38권3호
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    • pp.21-28
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    • 2015
  • As film products are increasingly used in a wide range of areas, from producing traditional flexible packaging to high-tech electronic products, a higher level of quality is demanded. Most film products are made in the form of rolled finished goods, therefore, various quality issues related to their shape characteristics must be addressed. The thickness of the film products is one of the most common and important critical-to-quality attributes (CTQs). Particularly, the degree of thickness uniformity is more important than other thickness parameters, because it will be potential causes of many secondary thickness-related quality problems, such as wrinkles or faulty windings. To control the degree of thickness uniformity, the fixed bending region is oneof the most important CTQs to manage. Fixed bending regions are special points in the transverse direction of a rolled product with consistent minute variations of the thickness gap. This paper describes the measurement and analysis of thickness uniformity data, which were performed in a real manufacturing field of biaxial oriented polypropylene (BOPP) film. In previous researches, quality function deployment (QFD) or fault tree analysis were used to find the most critical process attributes out to controlthe CTQ of thickness uniformity. Whereas, this paper uses traditional control charts to find the most critical process attributes out in this problem. In addition, the selection of one of the major critical process attributes (CTPs) that is expected to affect the CTQ of thickness uniformity is also described. The selected critical-to-process attributes are the controlled temperatures along the transverse direction. A dramatic improvement in thickness uniformity was observed when the selected CTPs were controlled.

수작농가(水稻作農家)의 적정영농규모계측(適正營農規模計測)에 관(關)한 연구(硏究) -강원도 철원군 평야지역 농가를 중심으로- (A Study on an Estimation of Optimum Rice Farm Size)

  • 김종필;임재환
    • 농업과학연구
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    • 제32권1호
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    • pp.81-94
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    • 2005
  • This study is aimed at giving the basic information for individual farm households to make decisions for optimizing their farm sizes and for the government to implement farm size optimization policies through the identification of combinations among rice production factors in plain areas like Cheolwon district and the suggestion of the optimal farm sizes of individual farmers based on the scale of economy calculated. The data of agricultural production costs of 50 rice farmers in the plain area which is located in Dongsong-eup Cholwon district, Kangwon province were used in the analysis. The 'translog' cost function among various methods which is a flexible function type was adopted to calculate the scale of economy in rice production. Seemingly unrelated regression(SUR) method was used in forecasting functions and processing other statistics by SHAZAM which is one of the computer aid program for quantitative econometric analysis. In conclusion, the long-run average cost(LAC) curve showed 'U-shape' which was different from 'L-type' one which was shown in the previous studies by others. The lowest point of the LAC was 9.764ha and the concerned production cost amounted to 633 Won/kg. Based on these results, it have to be suggested that around 10 ha of paddy is the target size for policy assistances to save costs under the present level of farming practices and technology. The above results show that the rice production costs could be saved up to 10ha in Cheolwon plain area which is a typical paddy field. However, land use, land condition, land ownership and manager's ability which may affect scale of economy should be considered. Furthermore, reasonable management will have to be realized by means of labor saving technology and cost saving management skill like enlargement of farm size of rice.

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