• Proceedings of the KIEE Conference
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• 2001.11a
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• pp.65-68
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• 2001

본 연구에서는 코움 드라이브에 비해 구동력은 크고 평행 판 구동 방식에 비해서는 선형 특성이 우수하며 안정된 구동거리가 증가하는 특성을 갖는 새로운 정전력(electrostatic force) 구동 방식을 제안한다. 운동 전극과 고정 전극을 기울어지게 배치하여 전극 면에 평행한 정전력 $F_x$와 전극 면에 수직인 정전력 $F_y$의 합력 $F_e$ 방향으로 전극을 운동시킴으로써 정전력의 방향과 전극의 운동 방향을 일치시킨다. 제안된 구동방식의 정전력 모델을 이용한 해석 결과 코움 드라이브에 비해서는 구동력이 50 % 이상 크며 평행 판 구동에 비해서는 안정된 구동 거리가 10 - 30 % 이상 증가하는 구동 특성을 얻을 수 있었다. 제안된 구동방식을 이용하여 HDD의 트랙 방향 저장 밀도를 증가시키기 위한 듀얼스테이지 서보(dual-stage servo)에 사용 될 마이크로 액츄에이터 (microactuator)를 설계하고 SoG(Silicon on Glass) 공정을 이용하여 제작하였다.

• Journal of the Korean Arthroscopy Society
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• v.7 no.2
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• pp.160-168
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• 2003

Purpose : To analyze the anterior stability and functional results after the arthroscopic ACL reconstruction and meniscectomy based on meniscus status at the time of surgery. Materials and Methods : From October 1997 to October 2002, 78 patients (male 64 female 14) were treated by arthroscopic ACL reconstruction and meniscectomy and followed more than 12 months (range, $12\~72$ months, average: 32 months). Average age was 32 years old (range, $18\~57$ years old). We divided the patients into 4 groups; Both menisci was intact (BMI, control group), lateral meniscus removed (LMR), medial meniscus removed (MMR) and both menisci removed (BMR). Anterior passive displacement (objective stability) was estimated using KT-2000 arthrometer under the loading of 15lb,20lb and 30lb and evaluated anterior drawer test, Lachman test, range of motion, thigh circumference. Functional evaluation system of IKDC, OAK and Lysholm knee score was used. Results : Average anterior displacement under the loading of 30lb were 2.47 mm, 2.96 mm, 2.96 mm and 3.57 mm in each group(BMI, LMR, MMR, BMR) and it was statistically significant difference (p<0.05). There is no statistically significant difference in average anterior displacement under the loading of 15lb and 20lb in each group but it has showed decreasing tendency in meniscal removed groups. The mean anterior displacement was within 3 mm in 21 cases, 15 cases, 24 cases and 12 cases (total 72 cases, $94\%$) under the loading of 15lb and 20 cases, 15 cases, 24 cases and 11 cases (total 70 cases, $91\%$) under the loading 20lb of in each group and postoperative knee joint stability has showed increasing tendency (p>0.05). The mean score was 94.5, 93.2, 92.2 and 90.4 points in each group and 71 cases $(91\%)$ were more than excellent or good with a OAK score and fair results were noted 4 cases in both meniscal removed group. There were 65 cases $(83\%)$ with a Lysholm knee score more than excellent or good, and IKDC grading were more than normal or nearly normal in 74 cases $(95\%)$ except 4 cases (2 cases in MMR group and 2 cases in BMR group). Conclusion : Long-term anterior stability and functional results of a successful ACL reconstruction affected by tile status of the menisci at the time of surgery and KT-2000 arthrometer was good for estimation of objective follow up.

• Journal of the Korean Society of Radiology
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• v.14 no.3
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• pp.235-243
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• 2020

Lumbar Lordosis Angle (LLA) is an index that can be used to evaluate the curvature of the lumbar vertebrae. It can measure the structural stability of the lumbar spine and the stability of each segment of the vertebral column at the intervertebral disc angle (IDA). Especially, our data shows it is found to be a strong positive correlation between obesity and the angle of lordosis for lumbar vertebrae. Also, the reason for the large IDA in the case of obesity seems to be the result of the weakening of anatomical structure as well as the gravity effect. And, the obesity interferes with normal sagittal balance and fails to maintain a straight posture with minimal energy. Therefore, the obesity can be an important factor in causing back pain by changing the lumbar lordosis.

• The KIPS Transactions:PartB
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• v.13B no.4 s.107
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• pp.353-360
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• 2006

This paper presents a robust algorithm for segmenting a vehicle license plate area from a road image. We consider the features of license plates in three aspects : 1) edges due to the characters in the plate, 2) colors in the plate, and 3) geometric properties of the plate. In the preprocessing step, we compute the thresholds based on each feature to decide whether a pixel is inside a plate or not. A statistical approach is applied to the sample images to compute the thresholds. For a given road image, our algorithm binarizes it by using the thresholds. Then, we select three candidate regions to be a plate by searching the binary image with a moving window. The plate area is selected among the candidates with simple heuristics. This algorithm robustly detects the plate against the transformation or the difference of color intensity of the plate in the input image. Moreover, the preprocessing step requires only a small number of sample images for the statistical processing. The experimental results show that the algorithm has 97.8% of successful segmentation of the plate from 228 input images. Our prototype implementation shows average processing time of 0.676 seconds per image for a set of $1280{\times}960$ images, executed on a 3GHz Pentium4 PC with 512M byte memory.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1A
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• pp.183-190
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• 2006

Minimizing the self weight of long-span deck slabs is one of the key factors for the practical and economic design of a composite two-girder bridge. In this paper, the minimum design thickness and rebar details of prestressed concrete deck slabs for composite two-girder bridges with girder span length from 4 m to 12 m are studied based on the safety and serviceability. The bridge deck slab with minimum thickness is designed as a one-way slab considering orthotropic behavior. Then fatigue safety of the deck slab is examined. Serviceability requirements for the deck slab such as deflection and crack width limits are also examined. The result shows that rebars with diameter less than 16 mm is recommended for the improved fatigue behavior, and, for the deck slab with span length longer than 8 m, the deflection limit governs the minimum design thickness. The result also shows that, for the deck slab with span length longer than 4 m, the distribution rebar requirement in the current Korea Highway Bridge Design Code is not sufficient to maintain the structural continuity in bridge axis as expected from the deck slab with span length shorter than 3 m.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2002.05a
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• pp.71-78
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• 2002

본 연구에서는 아동 성격검사지(Personality Inventory for Children: PIC)의 하위척도 중의 하나인 비행척도 점수가 높은 아동과 낮은 아동의 안정상태 시의 생리반응 특성을 밝히고, 다양한 정서 유발조건에서의 생리반응 변화의 특성을 규명하고자 하였다. 87명의 아동이 실험에 참여하였으며, 아동의 연령범위는 7∼9세였다. 안정상태와 각 정서(기쁨, 분노, 슬픔, 스트레스)를 유발하는 동안에 심전도(Electrocardiogram: ECG)와 피부전기활동(Electrodermal activity: EDA)을 측정하였다. 각 정서 유발자극이 제시된 후, 아동들은 자신이 느낀 정서를 보고하였다. 한국판 아동용 성격검사지에 포함되어 있는 비행척도 문항을 이용해 아동의 비행점수를 계산하였으며, 비행척도 점수가 높은 아동과 낮은 아동을 각각 임의로 12명씩 선정하였다 비행척도 점수가 높은 아동은 비행척도 점수가 낮은 아동에 비해 안정상태에서 피부전도수준(Skin conductance level: SCL)과 심장박동률(Heart rate: HR)이 낮은 것으로 나타났다. 정서를 유발하는 조건에서도 비행척도 점수가 높은 아동은 비행척도 점수가 낮은 아동에 비해 피부전도수준 변화와 심박률 변화가 적었다.

• Proceeding of EDISON Challenge
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• 2013.04a
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• pp.316-320
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• 2013

본 논문은 일반 항공기와 카나드를 장착한 항공기의 차이점을 알아보기 위해 카나드와 주익의 수평위치에 따른 공력특성을 비교하였다. 카나드를 장착한 비행기는 비행 안정성에 이점을 얻을 수 있고 주익(Main wing)에서의 실속 현상을 미연에 방지 할 수 있는 장점이 있다. 이러한 현상을 알아보기 위해 카나드와 주익간의 위치를 변화시켜 그에 따른 공력특성을 EDISON 프로그램을 통해 해석하여 보았고 이를 ANSYS의 FLUENT를 이용하여 해석한 결과와 비교분석하여 신뢰성을 확보 할 수 있었다.

• Korean Journal of Optics and Photonics
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• v.11 no.2
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• pp.130-134
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• 2000

In this paper, the configuration of a reflectIve bistable tWIsted nematic (BTN) liquid crystal cell is optmnzed for high contrast and high brightness operation. We searched for the optimum opncal parameters of a reflective BTN cell by calculating its optical performances at 3 wavelengths; red, green, and blue. By studying the effect of each optical parameter on the optical performances, we found that the angle of !he polmlzer IS more important than any other opnea! parmlleters iu the deSIgn of a reflective BTN cell. We fablicated a reflective BTN cell with a wide-band retardation Him, whose measmed contrast ratio is 10.6: 1. .6: 1.

• Journal of Korean Society of Steel Construction
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• v.10 no.3 s.36
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• pp.451-461
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• 1998

The solution of anisotropic plate via the classical methods is limited to relatively load and boundary conditions. If these conditions are more complex, the analysis becomes increasingly tedious and even impossible. For many plate problems of considerable practical interest, analytic solutions to the governing differential equations cannot be found. Among the numerical techniques presently available, the finite difference method and the finite element method are powerful numerical methods. The objective of this paper is to compare with each numerical methods for the buckling load and modes of anisotropic composite laminated plates considering shear deformation. In applying numerical methods to solve differential equations of anisotropic plates, this study uses the finite difference method and the finite element method. In determining the eigenvalue by Finite Difference Method, this paper represent good convergence compared with Finite Element Method. Several numerical examples and buckling modes show the effectiveness of various numerical methods and they will give a guides in deciding minimum buckling load and various mode shapes.

• The Journal of Engineering Geology
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• v.22 no.1
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• pp.49-58
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• 2012

Anchor heads a recommonly exposed to surface weathering processes that cause physical damage by vibration and external forces. This study presents a new method of anchor-head installation that uses near-surface embedding based on analyses of concrete block failure. ABAQUS 3D numerical modeling performed to compare this method with the standard technique and to analyze the distribution of displacement and the stress pattern. In addition, application of the method to a real-world case was tested by in-situ measurements. The results show a maximum vertical stress of 9.73 MPa and vertical displacement of 1.34 mm. Field tests indicated that displacement of a concrete block was 3 to 4 times greater than that of an embedded bearing plate.