• 대한조선학회논문집
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• 제44권5호
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• pp.517-525
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• 2007

This paper presents how to approximate an optimal shape of roll bending process in the fabrication of a curved shell plate. The roll bending process usually makes the cylindrical or conic shape from an initial flat plate. It means that the final shape is developable or its surface representation has zero Gaussian curvature. The fabrication shape is important in order to find process parameters of roil bending. An optimal concept is used to determine the developable fabrication shape which is in the closest proximity to the design surface or the given shell plate and is subject to developability. The results and the efficiency of this algorithm are evaluated by applying to some shell plates. Furthermore, the fabrication shape will be fundamental information for other process parameters of roll bending such as the vertical displacement of the center roller and the rolling directions.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 춘계종합학술대회
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• pp.493-496
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• 2005

본 논문에서는 번호판 고유의 복합 색상 정보와 수직 에지 정보를 이용한 번호판 후보 영역 추출기법을 제안한다. 또한 추출된 번호판 영역의 정확성을 높이기 위해서, Fast DCT를 거쳐 압축된 이미지에 대하여 Support Vector Machines(SVM)을 이용한 검증 과정을 제안한다. 제안하는 기법은 차량번호판 인식의 대상이 되는 자동차의 위치가 정면, 후면을 구분하지 않는 다양함을 가지고, 주변 배경이 충분히 포함되는 상황에서 다양한 크기를 가지는 355장의 영상들을 대상으로 한다. 실험 결과, SVM을 이용한 검증 과정을 거친 방법이 그렇지 않은 경우보다 20%이상 향상된 번호판 추출 성공률을 나타내었다.

• 자원환경지질
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• 제7권1호
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• pp.1-21
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• 1974

From the point of view of geological history, the land of South Korea is regarded as the subject of processes of the changes in formations of several geological blocks such as Kyonggi massif, Yeongnam massif, Taebaegsan basin, Kyungsang basin and so on. Through the long period of geological chronology, the present topography and geotectonics have been formed by the complicate interactions of epirogenetic movements, magmatism, orogenesis, differential vertical movements, metamorphism and sedimentation. The reason of the crust movements mentioned above, is suppossed that the Pacific and West Pacific plate have subducted directly or indirectly into the East Asia plate. This fact can be endorsed by the results of the studies on the heat flow, gravity anomaly, absolute age dating, tectonic lineation, lithofacies and the temperature of hot spring in South Korea. The formations of metal ore deposits as well as other geological processes can be determined by the mechanical control of the plates and be divided into several systematic patterns. The investigation of about 110 metal mines in South Korea shows the following results. (1) Plate boundary volcanic type is about 28% (2) Plate boundary plutonic type is about 44% (3) Intraplate sedimentary type is about 26% (4) Intraplate magmatic type is about 2%.

• 대한치과교정학회지
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• 제54권2호
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• pp.108-116
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• 2024

Objective: A three-dimensional-printed individual titanium plate was applied for maxillary protraction to eliminate side effects and obtain the maximum skeletal effect. This study aimed to explore the stress distribution characteristics of sutures during maxillary protraction using individual titanium plates in various directions and locations. Methods: A protraction force of 500 g per side was applied at forward and downward angles between 0° and 60° with respect to the Frankfort horizontal plane, after which the titanium plate was moved 2 and 4 mm upward and downward, respectively. Changes in sutures with multiple protraction directions and various miniplate heights were quantified to analyze their impact on the maxillofacial bone. Results: Protraction angle of 0-30° with respect to the Frankfort horizontal plane exhibited a tendency for counterclockwise rotation in the maxilla. At a 40° protraction angle, translational motion was observed in the maxilla, whereas protraction angles of 50-60° tended to induce clockwise rotation in the maxilla. Enhanced protraction efficiency at the lower edge of the pyriform aperture was associated with increased height of individual titanium plates. Conclusions: Various protraction directions are suitable for patients with different types of vertical bone surfaces. Furthermore, when the titanium plate was positioned lower, the protraction force exhibited an increase.

• 한국전산구조공학회논문집
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• 제28권3호
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• pp.267-274
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• 2015

본 논문은 넓은 보의 전단강도를 대상으로 한 실험적 평가에 대해 기술하였다. 본 논문의 실험을 통해 넓은 보에 횡방향 단면에서 GFRP 판의 보강개수와 종방향 전단보강 간격, 그리고 유효깊이가 전단강도에 끼치는 영향에 관하여 연구하였다. 총 7개의 시험체에 유공형 GFRP 판 형태로 전단보강재를 보강하여 전단성능 실험을 실시하였다. 본 논문에 기재된 전단보강재는 유공형 판 형태로 제작되어 타설 시 콘크리트의 유동성을 증가시켜 보강재와 콘크리트의 부착력을 향상시켰다. 7개 시험체의 주 변수로는 전단보강재의 횡방향 단면에 대한 판의 보강개수와 종방향 전단보강 간격, 그리고 유효깊이로 정하였다. 시험체의 균열 및 파괴 양상, 변형률과 전단강도비를 분석하였다. GFRP판으로 전단보강된 넓은 보의 전단강도는 ACI 318-11 기준으로 산정되었다. 실험의 결과를 통해 유공형 GFRP 판이 전단보강재로서 넓은 보에 효과적으로 적용됨을 확인하였다.

• 한국세라믹학회지
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• 제43권4호
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• pp.259-263
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• 2006

The applicability of UPT (Ultrasound Pulse Thermography) for real-time defect detection of the ceramic heating plate is described. The ceramic heating plate with superior insulation and high radiation is used to control the water temperature in underwater environment. The underwater temperature control system can be damaged owing to the short circuit, which resulted from the defect of the ceramic heating plate. A high power ultrasonic energy with pulse duration of 280 ms was injected into the ceramic heating plate in the vertical direction. The ultrasound excited vibration energy sent into the component propagate inside the sample until they were converted to the heat in the vicinity of the defect. Therefore, an injection of the ultrasound pulse wave which results in heat generation, turns the defect into a local thermal wave transmitter. Its local emission is monitored and recorded via the thermal infrared camera at the surface which is processed by image recording system. Measurements were Performed on 4 kinds of samples, composed of 3 intact plates and the defect plate. The observed thermal image revealed two area of crack in the defective ceramic heating plate.

• 한국전자통신학회논문지
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• 제5권5호
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• pp.471-476
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• 2010

본 논문에서는 RGB 컬러 정보와 오류 역전파 신경망 알고리즘을 이용한 신 차량 번호판 인식 방법을 제안한다. 먼저, 차량 영상에서 평균 Blue값을 이용하여 차량 영상을 보정하고 픽셀값의 차를 이용하여 Red 후보 영역과 Green 후보 영역으로 구분한 후 오류 역전파 알고리즘에 적용하여 최종 Green 영역을 찾는다. 둘째, 수평 및 수직 히스토그램의 빈도수를 이용하여 번호판 영역을 추출한다. 마지막으로, 윤곽선 추적 알고리즘을 적용하여 개별 코드들을 추출하고, 오류 역전파 알고리즘을 적용하여 개별 코드들을 인식한다. 제안된 차량 번호판 추출 및 인식 방법의 성능을 평가하기 위하여 실제 비영업용 신 차량 번호판에 적용한 결과, 제안된 번호판 추출 방법이 기존의 HSI(Hue Saturation Intensity) 정보를 이용한 번호판 추출 방법보다 추출률이 개선되었고 제안된 차량 번호판 인식 방법이 효율적인 것을 확인하였다.

• Structural Engineering and Mechanics
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• 제21권6호
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• pp.713-735
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• 2005

Due to the complexity of mathematical expressions, the literature concerning the free vibration analysis of plates carrying multiple three-degree-of-freedom (dof) spring-mass systems is rare. In this paper, the three degrees of freedom (dof's) for a spring-mass system refer to the translational motion of its lumped mass in the vertical ($\bar{z}$) direction and the two pitching motions of its lumped mass about the two horizontal ($\bar{x}$ and $\bar{y}$) axes. The basic concept of this paper is to replace each three-dof spring-mass system by a set of equivalent springs, so that the free vibration characteristics of a rectangular plate carrying any number of three-dof spring-mass systems can be obtained from those of the same plate supported by the same number of sets of equivalent springs. Since the three dof's of the lumped mass for each three-dof spring-mass system are eliminated to yield a set of equivalent springs, the total dof of the entire vibrating system is not affected by the total number of the spring-mass systems attached to the rectangular plate. However, this is not true in the conventional finite element method (FEM), where the total dof of the entire vibrating system increases three if one more three-dof spring-mass system is attached to the rectangular plate. Hence, the computer storage memory required by using the presented equivalent spring method (ESM) is less than that required by the conventional FEM, and the more the total number of the three-dof spring-mass systems attached to the plate, the more the advantage of the ESM. In addition, since manufacturing a spring with the specified stiffness is much easier than making a three-dof spring-mass system with the specified spring constants and mass magnitude, the presented theory of replacing a three-dof spring-mass system by a set of equivalent springs will be also significant from this viewpoint.

• 한국전기전자재료학회논문지
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• 제36권3호
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• pp.298-302
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• 2023

In this paper, we discussed the effect of field plate dielectric materials such as silicon dioxide (SiO₂), aluminum oxide (Al₂O₃), and hafnium oxide (HfO₂) on the breakdown characteristics of β-Ga₂O₃ Schottky barrier diodes (SBDs). The breakdown voltage (BV) of the SBDs with a field plate was higher than that of SBDs without a field plate. The higher dielectric constant of HfO₂ contributed to the superior reduction in electric field concentration at the Schottky junction edge from 5.4 to 2.4 MV/cm. The SBDs with HfO₂ field plate showed the highest BV of 720 V, and constant specific on-resistance (R_on,sp) of 5.6 mΩ·cm², resulting in the highest Baliga's figure-of-merit (BFOM) of 92.0 MW/cm². We also investigated the effect of dielectric thickness and field plate length on BV.

• Anatomy and Cell Biology
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• 제56권4호
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• pp.456-462
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• 2023

Plate fixation has become the preferred approach for treating displaced midshaft clavicle fractures. However, plate fixation of the clavicle presents several unique challenges, including its complex bony architecture and its immediate subcutaneous location. In many cases, we have observed that precontoured implants do not conform to the clavicular anatomy, and many patients complain of postoperative implant-related discomfort. A total of 111 clavicles, both left and right sides, were examined to match two commonly used designs of anatomical pre-contoured superior anterior clavicle plates, with and without lateral extension. The anteroposterior (AP) plane congruence of the plate to the underlying bone, the vertical gap between the bone and plate, and the length of the plate that was off the bone either anteriorly and/or posteriorly at both ends of the clavicle were measured. The scoring system was used to determine the fit of the implant on the clavicle as anatomic, good, or poor. We found that the maximum superior bow of the clavicle was lateral to the midline by 30.75 mm and 30.5 mm on the right and left sides, respectively. The magnitude of the bow was 4.28 mm and 4.46 mm on the right and left sides, respectively. We also found that the plate was a poor fit in 75.86% of cases on the left side and 73.5% of cases on the right side. Manipulating the plates during surgery was very difficult in the AP plane.