• 제목/요약/키워드: Drawing Angle

검색결과 154건 처리시간 0.024초

유한요소해석에 의한 절대코일 와전류 신호의 임피던스 평면도 작성 (Drawing of Impedance Plane Diagrams of Absolute Coil ECT Signals by finite Element Analysis)

  • 신영길;이윤태;이정호;송명호
    • 비파괴검사학회지
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    • 제24권4호
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    • pp.315-324
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    • 2004
  • 와전류 탐상에서 차동형 탐촉자는 신호에 영향을 미치는 변수들을 줄일 수 있어 흔히 사용된다 그러나 차동신호는 인접한 두 코일의 임피던스 차이를 신호로 사용하기 때문에 신호예측이나 해석이 쉽지 않다는 단점이 있다. 반면에 절대코일에 의한 신호는 상대적으로 형태가 단순하므로 신호예측이나 해석이 더 수월하다. 따라서 서로의 장, 단점을 상호보완적으로 사용하면 검사 신뢰도를 향상시키는데 큰 도움이 될 것이다. 본 논문에서는 인코넬 평판과 튜브에서 절대코일 신호를 예측하기 위하여 유한요소해석을 수행하였고, 리프트 오프, 충전율, 전도도, 탐상 주파수, 피검사체의 두께, 내, 외부 결함 등이 신호에 미치는 영향을 계산하여 임피던스 평면도로 작성하고, 신호특징을 분석하였다. 그 결과, 절대신호에 대한 많은 실용적인 지식을 축적할 수 있었고, 절대신호와 차동신호 특성의 유사성을 이해하게 되었으며, 결함깊이와 주파수 변화에 따른 신호의 기울기를 대응곡선 그래프로 자성할 수 있었다.

3D프린터를 이용한 겨울철 대류난방기구의 온도 성층화 해결을 위한 무동력 서큘레이터 디자인에 관한 연구 (The A Study on the Non-powered Circulator to Solve the Temperature Stratification of a Convection Heating Device during Winter Using 3D Printer)

  • 강희라
    • 디지털융복합연구
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    • 제19권6호
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    • pp.285-292
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    • 2021
  • 최근 코로나19 사태로 캠핑 문화가 급속하게 많은 사람들에게 관심을 받고 있다. 많은 캠퍼들이 겨울철 사용하는 대류난방기구는 온도 성층화 문제를 가지고 있다. 이를 해결하기 위해 다양한 동력 서큘레이터가 활용되고 있다. 몇 가지 무동력 서큘레이터도 판매가 되고 있으나, 서큘레이터의 방향이 대류난방기구와 직각으로 디자인되어 있어 실제 공기 순환의 역할을 제대로 하지 못하고 있다. 이러한 문제점을 해결하고자 3D 프린터를 이용하여 대류난방기구의 방향과 같은 무동력 서큘레이터를 디자인하였다. 펠티어소자와, 세라믹페이퍼 등을 이용하여 무동력으로 전기를 만들어 냈으며, HTPLA-CF 필라멘트를 이용하여 열에 강하게 제작하였다. 3D 프린터를 이용하여 원가를 절감할 수 있었으며, 다양한 대류난방기구의 크기에 맞게 제작 할 수 있는 장점이 있다. 본 연구는 효율적인 대류순환을 통해 온도 성층화 문제를 해결할 수 있는 하나의 방법을 제시한다. 또한 3D 프린터를 이용하여 보다 저렴하게 제품을 제작하는 것이 본 연구의 목적이다.

시뮬레이션을 이용한 충돌 전후 차량 진행궤적 분석 (Analysis of vehicle progress before and after a collision using simulation)

  • 한창평
    • 한국산학기술학회논문지
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    • 제22권1호
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    • pp.402-408
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    • 2021
  • 기계 설계를 기반으로 제작한 자동차에 의한 사고 발생 시 차량 공학적인 분석은 심도 있게 조사하지 않고 조사자의 주관적인 경험 지식을 토대로 분석하는 경우가 있다. 본 연구는 실제 발생한 중앙선 침범 사고 자료를 토대로 캐드(CAD) 프로그램을 이용하여 현장 상황을 도면화하고, 도면화 한 자료를 시뮬레이션 프로그램(PC-Crash)에 적용하여 250번의 충돌 상황을 반복적으로 수행하여 최종 정지 위치 및 최종 정지 자세와 부합하는 충돌 속도, 진행 자세, 조향 작동 여부 및 제동 여부 등의 상관 관계를 분석했다. 충돌 속도가 낮을수록 이탈각의 영향을 크게 받지 않고 속도가 높은 차량의 속도에 영향을 크게 받고 충돌 이후에는 유효 충돌 속도와 같이 속도가 낮은 차량은 높아지고, 속도가 높은 차량은 낮아진다. 본 연구의 시뮬레이션 결과는 마이티가 중앙선을 넘은 자세로 오르막 좌커브 구간을 진행하다가 마주오던 포터를 인지하고 자기 진행 차로로 복귀하는 과정과 포터의 전면 좌측면이 충돌하여 포터가 우대각선 방향으로 밀려나 전면이 약 11시 방향을 향해 최종 정지하는 것을 규명하였다.

Crack detection in folded plates with back-propagated artificial neural network

  • Oguzhan Das;Can Gonenli;Duygu Bagci Das
    • Steel and Composite Structures
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    • 제46권3호
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    • pp.319-334
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    • 2023
  • Localizing damages is an essential task to monitor the health of the structures since they may not be able to operate anymore. Among the damage detection techniques, non-destructive methods are considerably more preferred than destructive methods since damage can be located without affecting the structural integrity. However, these methods have several drawbacks in terms of detecting abilities, time consumption, cost, and hardware or software requirements. Employing artificial intelligence techniques could overcome such issues and could provide a powerful damage detection model if the technique is utilized correctly. In this study, the crack localization in flat and folded plate structures has been conducted by employing a Backpropagated Artificial Neural Network (BPANN). For this purpose, cracks with 18 different dimensions in thin, flat, and folded structures having 150, 300, 450, and 600 folding angle have been modeled and subjected to free vibration analysis by employing the Classical Plate Theory with Finite Element Method. A Four-nodded quadrilateral element having six degrees of freedom has been considered to represent those structures mathematically. The first ten natural frequencies have been obtained regarding healthy and cracked structures. To localize the crack, the ratios of the frequencies of the cracked flat and folded structures to those of healthy ones have been taken into account. Those ratios have been given to BPANN as the input variables, while the crack locations have been considered as the output variables. A total of 500 crack locations have been regarded within the dataset obtained from the results of the free vibration analysis. To build the best intelligent model, a feature search has been conducted for BAPNN regarding activation function, the number of hidden layers, and the number of hidden neurons. Regarding the analysis results, it is concluded that the BPANN is able to localize the cracks with an average accuracy of 95.12%.

무릎 체중부하 촬영 보조장치 개발 (Development of Knee Weight-bearing Radiography Assist Device)

  • 김연래;윤영우
    • 대한방사선기술학회지:방사선기술과학
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    • 제46권5호
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    • pp.395-399
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    • 2023
  • The knee arthritis patients are generally performed standing position radiography. However, patients with pain caused by degenerative diseases or injuries in the knee have difficulty maintaining a standing position. Therefore, this study aims to develop a knee joint standing weight bearing projection assist device to solve these problems when patients undergo knee radiography due to various diseases. The design of the knee joint weight-bearing radiography assist device is carried out with 3D design and drawing production to secure basic data, electric support and frame manufacture. A fixed device for maintaining the patient's knee standing weight-bearing projection, an electric digital height device, a digital protractor, and a safety device were designed. The arm support is made of PVC with a cushion to relieve the impact and make it easier to remove debris. The digital electric device can be moved up and down according to the patient's height, and a remote control is attached. The safety device is made to be adjustable in size by attaching metal hooks on both sides of the frame and to shield the scrotum. A digital protractor was attached to the side frame to set the desired knee angle. When a self-made assist device was used to perform a knee joint standing weight bearing projection, it helped maintain arm support and lower extremities position. In addition, the height could be adjusted using an assist device during standing projections, which helped the patient maintain the position.

Openbite을 나타내는 성인의 치열 특성 및 그에 따른 골격적 특성 분석 (An analysis of the dental arch and skeletal characteristics in adult patients exhibiting open bite)

  • 이진우
    • 대한치과교정학회지
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    • 제34권4호
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    • pp.289-301
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    • 2004
  • It is the purpose of this study to characterize oral symptoms and to comprehend the cause and the relapse possibility of patients with open bite. This case study examines the orthodontic treatment of a group of female patients with open bite and Angle's Class I malocclusion. A cephalograph of the patient was taken and tracing of the radiograph was completed. In addition to Bjork and Ricketts analysis, additional measurements of specific areas were taken. The occlusal plane was determined by drawing a line connecting the mesiobuccal cusp tip of the maxillary first molar and the incisal edge of the maxillary central incisors. Patients were divided into two groups depending on the relationship between the marginal ridge of the maxillayy first premolar and the drawn line. Those patients with marginal ridges above the occlusal plane were placed into Group 1, while Group 2 subjects exhibited marginal ridges lower than the occlusal plane. The common characteristics within each group and the characteristic differences between each group both prior to and after orthodontic treatment were examined, and finally, the functional oral volume of each patient was analyzed. The results of the case study were as follows: 1. An examination of the skeletal relationship and anatomical form for both Group 1 and 2 showed that all subjects exhibited hyperdivergent skeletal forms, but Group 2 subjects generally demonstrated underdevelopment of the mandible and a smaller articular angle, resulting in an anterior positioning tendency of the mandible. 2. An analysis of the maxillary arches of Group 1 subjects prior to and after orthodontic treatment showed that the antero-inferior direction had changed to an antero-superior directional tendency, while the maxillary arches of the Group 2 patients showed a trend from an antero-superior direction to an antero-inferior relationship. The mandibular arches in both groups showed a change to an antero-superior direction. 3. Functional space analysis showed that Group 2 patients exhibited a greater tendency of haying palatal planes that drop in a postero-inferior direction, resulting in a more severe open bite than their Group 1 counterparts. The results of this case study show that although patients belonging to either Group 1 or 2 exhibited few external differences in the appearance of open bite, an examination of the dental and skeletal relationships by analyzing patient cephalographs showed that patients presenting with flat maxillary occlusal planes exhibited more severe open bite relationships than patients with curved occlusal planes.

Biomechanical Effectiveness and Anthropometric Design Aspects of 3-dimensional Contoured Pillow

  • Kim, Jong Hyun;Won, Byeong Hee;Sim, Woo Sang;Jang, Kyung Seok
    • 대한인간공학회지
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    • 제35권6호
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    • pp.503-517
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    • 2016
  • Objective: The aim of this study was to evaluate the effectiveness of 3 dimensional contoured pillow through analyzing contact pressure and to suggest its design guidelines through analyzing the posture of head and neck area. Background: The quality of sleep is a very important factor closely related with human's health. To improve the quality of sleep, the verification of design factors affecting the posture of the head and neck is needed, and a pillow design that can induce proper posture is required. Method: This study measured the contact pressures of the two reference groups (bead and cotton pillows) as a method to evaluate the design effectiveness of the contoured pillow. This study proposed 3-dimensional design guidelines by drawing anthropometry (head length) affecting cervical curvature angle (CCA) through the measurement of the participants' cervical curvature angles. Results: In the design effectiveness evaluation, the contact pressure of cervical region was higher than that of a reference group (cotton pillow), and contract area increased, and contract pressure decreased in the shape distributing the occipital region's body pressure. This study proposed pillow's cervical supporting height by percentile of a head length [head length (%tile) (cervical supporting height) affecting the posture of the head and neck: 14.6cm (5%tile) (6.2cm), 15.5cm (25%tile) (6.7cm), 16.4cm (50%tile) (7.1cm), and 19.3cm (75%tile) (8.9cm)]. Conclusion: This study confirmed the contoured pillow's design effectiveness maintaining cervical angle comfortable to sleep with the shape supporting the cervical vertebrae and by reducing the contact load of the occipital region. Also, this study proposed pillow design guidelines based on the 3-dimensional contoured pillow design effectiveness, through which the study laid the foundation for pillow design in a systematic method. Application: The results of this study are expected to be utilized as the basis data by which the optimum pillow type and pillow design according to main percentile can be standardized.

Superimposed Rubber Pattern법에 의한 성인 정상 및 비정상 교합자의 교합 양상에 관한 연구 (A STUDY OF THE NORMAL & ABNORMAL OCCULSAL PATERNS IN ADULTS USING THE SUPERIMPOSED RUBBER PATTERN METHOD)

  • 최대균;이성복;권영혁;최부병
    • 대한치과보철학회지
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    • 제33권3호
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    • pp.467-491
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    • 1995
  • In order to analyze the occlusin of intercuspation with maximun bite force, fifteen healthy adult subjects with the ages 23 to 27 were studied(Group1 ; 5-normal occlusion with Angle's Class1, Group2 ; 5-Angle's Class2 malocclusion, Group3 ; 5-Angle’s Class3 malocclusion). Head Position was fixed with occlusal plane paralleling to horizontal line and occlusal registration r cord was made with polyether rubber impression material(Ramitec, ESPECo. West Germany). After all subject were trained for maximum intercuspation at least 5 times, occlusal registration procedure was repeated for this study. Lower posterior rubber occlusal registration records were sliced with 1mm thickness using precision metal sliding channel(Hitachi Ind. Co., Japan). Gross sectional drawings were traced from occluding view of upper and lower posterior teeth on the rubber slices using digitizer, and superimposed for the determination of each drawing distance(Superimposed Rubber Pattern Method). Based on superimposed rubber pattern drawings, total area of occlusal view, sum of each area of the 5 divided occlusal contact provinces and its ratio, total area and number of occlusal contact area were determined to elucidate occlusal stability in the normal and abnormal occlusion groups. The data were analysed by t-test(p=0.05) to determine statistical significance. The obtained results were as follows : 1. Group1 showed the largest standard area with occlusal view of the lower posterior teeth and Group3 showed the smallest area. There was a significant difference between Group2 and Group3(p=0.025), and Gropu1 was not statistically different for both Group2 and Group3. 2. Means and ratio of the under 2.0mm area(D) and ratio showed $197.49mm^2$, 59.76% in Group1, $188,69mm^2$, 56.10% in Group2, and $174.23mm^2$, 55.76% in Group3. The results that Group1 has the most area/ratio and Group3 has the least area/ratio can be considered Group1 is the most advantageous for masticatory effective area, and Group3 is the least adnantageous. 3. Means and ratio of the under 1.0mm area(C) were $198.96mm^2$, 42.65% in Group1, 123.06$mm^2$, 46.58% in Group2, and $92.24mm^2$, 29.52% in Group3. These data means that Group1 is the most advantageous in terms of masticatory effective area and Group3 is the least. 4. Means and ratio of the under 0.5mm area(B) were $86.68mm^2$, 26.68% in Group1, $62.98mm^2$, 18.71% in Group2, and $36.44mm^2$, 11.66% in Group3. These can also be considered Group1 is the most advantageous for masticatory effective area and occlusal stability. 5. Means and ratio of the under 0.05mm area(A) were $30.92mm^2$, 9.21% in Group1, $14.31mm^2$, 4.25% in Group2, and $7.59mm^2$, 2.43% in Group3. The area ratio of the each subject group was(4.1) : (1.9) : (1)and the data of the under 0.05mm area has the intimate relationship with inter-group and intra-group data/ratio. 6. First molar showed the most occlusal contact points in all subject group and Group1 showed somewhat uniformly distributed occlusal contact point except first premolar. In Group2, all contact point in posterior teeth showed significantly reduced distribution except first molar. Group3 showed evenly distributed contace points in first and second molars.

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조망점 선정을 통한 대상지의 경관가치 평가 및 개선방안 (Landscape Assessment and Improvement of the View Area by Selecting the Landscape Control Point)

  • 김진효;이현택;나정화;조현주;사공정희
    • 한국조경학회지
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    • 제40권5호
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    • pp.19-32
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    • 2012
  • 본 연구의 목적은 대규모 주택단지 개발지로 계획되어 있는 대구광역시 북구 연경동 및 동구 지묘동 일원을 대상지로 선정하여 조망점 선정을 통해 조망대상 및 대상장을 정량적으로 평가해 보고, 이를 토대로 시뮬레이션을 실시하여 계획적 차원에서 개선방안을 제시해 보는데 가장 큰 의의를 두었다. 연구결과를 요약하면 다음과 같다. 우선 조망대상 선정을 위한 문헌분석 결과, 도출된 조망대상은 총 24개로 나타났으며, 최종적으로 도출된 주요 조망대상은 4가지로 나타났다. 다음으로 도출된 조망점 선정기준은 총 15개로 나타났으며, 이들은 다시 공통적인 특성에 따라 조망성, 접근성, 공공성으로 재분류하였다. 예비조망점은 공공성 및 접근성을 평가하여 선정하였으며, 평가 결과, 총 42곳의 예비조망점이 선정되었다. 최종조망점은 선정된 예비조망점을 대상으로 조망성을 평가하여 선정하였으며, 평가 결과 29개의 최종조망점이 선정되었다. 마지막으로 문헌분석 결과, 도출된 평가지표는 총 26개로 나타났다. 조망점별 가치평가 결과, 29곳의 대상장 중 I등급은 2곳, II등급은 3곳, 가장 낮은 V등급에 해당하는 대상장은 3곳으로 나타났다. 다음으로 개선방안을 위한 문제점 분석 결과, 개발계획도면을 고려하지 않은 대상장-1의 경우, 토지모자이크의 다양성 등 4가지 개선지표가 선정되었다. 또한 개발계획도면을 고려한 대상장-2의 경우, 배후 산림으로의 조망이 잘 이루어지며, 시각회랑의 확보가 가능한 건축물 배치 형태는 직각배치, 층수는 약 10층인 것으로 나타났다.

전력계통 운영조건을 고려한 발전기차단용 SPS 동작설정에 관한 연구 (A Study on Setting SPS for Generator Tripping Action considering Operating Conditions of Power Systems)

  • 권한나;손혁진;국경수;양성채
    • 한국산학기술학회논문지
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    • 제15권1호
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    • pp.411-417
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    • 2014
  • 발전기차단용 고장파급방지장치(SPS; Special Protection Scheme)는 대규모 발전단지의 인출 송전선로 고장시 발전단지 내의 발전기 과속을 방지하기 위해 사전에 계획된 대수만큼 해당 발전기를 즉시 차단하여 전력계통 전체의 안정도를 유지하는 비상 장치이다. 그러나 기존의 국내 발전기차단용 SPS 동작은 첨두부하를 기준으로 산정된 값을 일률적으로 적용하여 운영 되고 있어 경부하시에 발전기차단용 SPS가 동작을 하게 되면 발전기 과차단으로 인한 발전력 부족을 초래할 가능성이 있는 등 SPS 운영의 비효율성이 잠재되어있다. 이를 위해 본 논문에서는 수시로 변화하는 전력계통 운영조건을 주기적으로 취득하고 정확도와 속도가 우수한 COA기반의 안정도평가를 통해 발전기 차단용 SPS 동작을 설정함으로써 경부하시에는 SPS 발전기 탈락대수가 첨두수요 기준의 설정치보다 감소되어 계통 고장에 의한 SPS 동작 시 발전비용 증가를 경감 할 수 있다.