• Journal of the Korean Wood Science and Technology
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• 제44권6호
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• pp.828-841
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• 2016

Relatively little information is available regarding the correlation between wood and veneer quality, especially for Samama wood, an endemic wood species in eastern Indonesia. This study addresses the quality of 8 years old Samama wood and its effect on the veneer quality. Samama wood quality was determined by evaluating its specific gravity, moisture content, fiber dimensions, and microfibril angle from pith toward bark. Meanwhile, veneer quality was assessed by examining veneer thickness and lathe check characteristics. Geometry factor model was constructed to elaborate the quantities of lathe check from pith toward bark. Results show that fair variations of veneer thickness, ranging from 1.5 mm to 3.0 mm, could be obtained from Samama wood. The quantity, depth, and length of lathe check were noticeably decreasing toward bark. Further, in the same manufacturing process, geometry factor was determined as the dominant factor over other wood properties in affecting the frequency of lathe checks from pith towards bark. These facts should be put into consideration in producing veneer from Samama wood. Moreover, these results enlighten the potential of Samama wood as plywood and other excellent veneer-based products.

• Structural Engineering and Mechanics
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• 제12권2호
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• pp.201-214
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• 2001

Four finite element (FE) models are examined to find the one that best estimates moment-rotation characteristics of top- and seat-angle with double web-angle connections. To efficiently simulate the real behavior of connections, finite element analyses are performed with following considerations: 1) all components of connection (beam, column, angles and bolts) are discretized by eight-node solid elements; 2) shapes of bolt shank, head, and nut are precisely taken into account in modeling; and 3) contact surface algorithm is applied as boundary condition. To improve accuracy in predicting moment-rotation behavior of a connection, bolt pretension is introduced before the corresponding connection moment being surcharged. The experimental results are used to investigate the applicability of FE method and to check the performance of three-parameter power model by making comparison among their moment-rotation behaviors and by assessment of deformation and stress distribution patterns at the final stage of loading. This research exposes two important features: (1) the FE method has tremendous potential for connection modeling for both monotonic and cyclic loading; and (2) the power model is able to predict moment-rotation characteristics of semi-rigid connections with acceptable accuracy.

• 한국광학회지
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• 제12권3호
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• pp.235-239
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• 2001

본논문에서는 반강유전성 액정의 in-plane tilt 각이 약 $22.5^{\circ}C$인 특성을 가진다는 것을 이용하여 액정의 위상지연을 $\lambda/2$로 설계한 광대역 $\lambda/4$필름을 사용한 단일 편광판 모드 반사형 LCD의 구조를 제안하였으며 이구조의 여러 가지 광특석을 전사모사 해보았다. 실제 실험에서는 in-plane tilt 각이 $\24.9\lambda$인 Chisso상의 CS-4001 반강유전성 액정을 사용하여 액정 셀의 위상지연을 $\lambda/2$로 설계하여 각도에 따른 반사특성과 파장에 따른 분광특성을 측정하였다.

• 한국강구조학회 논문집
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• 제23권3호
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• pp.349-356
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• 2011

본 논문에서는 파라메트릭 기법을 이용한 최적설계 알고리즘을 사용하여 최근 들어 다양한 형태를 지니고 있는 비정형 초고층 구조물의 최적 다이아그리드 각도를 찾는 것에 대해 연구하였다. 다이아그리드는 비정형 초고층 구조물을 구성하는 대각방향의 부재로 수직하중과 수평하중에 대해 효과적으로 대응할 수 있는 구조 시스템으로써 다이아그리드의 각도를 최적화 하여 비정형 초고층 구조물의 최대강성을 찾는 것에 목적을 두었다. 본 연구에서 검증예제로 비정형 형상인 원통형 구조물과 테이퍼드 원형 구조물에 다이아그리드 최적설계 알고리즘을 적용하여 변위를 효과적으로 제어하는 다이아그리드의 최적각도를 검토하였다.

• 드라이브 ㆍ 컨트롤
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• 제19권3호
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• pp.39-46
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• 2022

In South Korea, to evaluate the rollover safety of domestic vehicles, the maximum slope angle of the vehicle is specified, which is verified by the rollover safety test of driving vehicles. However, the domestic rollover safety test is not suitable for buses, because the small amount of static stability factor (SSF) will invalidate the rollover experimental equation due to the high center of mass position of buses. To solve the above problems, a dynamic model of the bus is prepared with assumptions of mass and suspension spring properties. Subsequently, the maximum slope angle of the model was computed by using the simulation of multi-body dynamics, and the result was compared with actual test results to validate the dynamics model. Also, the rollover Fishhook (roll stability) test was conducted in the simulation for driving model. During the simulation, roll angle and roll rate were calculated to check if a rollover occurred. Through the rollover simulation of buses, the domestically regulated formula for rollover safety and the procedure of rollover test for driving vehicles are evaluated. The conclusion is that the present regulation of rollover test should be reconsidered for buses to ensure to get the valid results for rollover safety.

• 대한치과보철학회지
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• 제31권1호
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• pp.77-86
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• 1993

The purpose of this study was to compare the sagittal condylar guidance obtained by the graphic method(pantographic tracing) with that produced by the positional method(check-bite). Ten adults who had normal occlusion and were free of TMJ dysfunction were selected, and the clutches were constructed. At first pantographic survey was performed and the articulator was adjusted with each pantographic recording. And then three protrusive check-bite were taken on the subjects using the polyether$(Lamitec^{(R)})$ on the buccal side of the posterior teeth without the interocclusal record method and the vericheck method was performed with each protrusive check-bite. Sagittal condylar guidances obtained by using the pantograph and Vericheck were compared and analyzed statistically. The results were as follows: 1. The average condylar guidance ankle at 4mm and 7mm from centric relation point on the pantograph $(35.9{\pm}1.10^{\circ},\;32.4{\pm}1.55^{\circ})$ was statisccally significant(P<0.01). 2. The average condylar guidance angle of the Vericheck was $27.0{\pm}3.43^{\circ}$. 3. The comparison of the right and left was not statistically significant in all group(P>0.05). 4. The comparison of pantograph and Vericheck was statistically significant in the right and left(P<0.001).

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.201-204
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• 2005

Recently, the generation of panoramic images and high quality mosaic images from video sequences has been attempted by a variety of investigations. Among a matter of investigation, in this paper, left and right stereo mosaic image generation utilizing airborne-video sequence images is focused upon. The stereo mosaic image is generated by creating left and right mosaic image which is generated by front and rear slit having different viewing angle in consecutive video frame images. The generation of stereo mosaic image proposed in this paper consists of several processes: camera parameter estimation for each video frame image, rectification, slicing, motion parallax elimination and image mosaicking. However it is necessary to check the feasibility on generating stereo mosaic image as explained processes. Therefore, in this paper, we performed the feasibility test on generating stereo mosaic image using video frame images. In doing so, anaglyphic image for stereo mosaic images is generated and tested for feasibility check.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1238-1240
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• 2007

The wind force development system is applying variableness inside system recently. High-capacity system performs blade pitch check and main point check, but because pitch angle is fixed in case of capacity system, development efficiency drops. Must do to achieve variableness inside control about change of manners to be acted in maximum electric power point hereupon. Treatise that see hereupon proves this theoretically, and proved validity through 400 [W] experiments.

• 전기학회논문지
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• 제64권5호
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• pp.792-798
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• 2015

Joint angle generally can be measured to check the recovery process in rehabilitation field. This paper suggests to measure joint angle with Infrared sensor based on triangulation principle. We performed various experiments to find the optimal condition of the sensor’s attached distance, height, and angle. The results were compared with commercial goniometer for accuracy. The proposed infrared joint angle sensor can be effectively used in rehabilitation and sport science fields.

• PNF and Movement
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• 제18권1호
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• pp.127-132
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• 2020

Purpose: This study aimed to investigate the impact of resistance on the muscle activities of the long and short heads of the biceps brachii, according to the elbow angle in supination, and the difference in muscle activity between the long and the short heads. Methods: This study was conducted with 22 men in their 20s who voluntarily agreed to participate. With the glenohumeral joint neutral in a position of supination, the elbow angle was randomly moved to 0°, 30°, 60°, and 90°. Using an 8-channel surface EMG while the participants held a 2-kg. dumbbell, the muscle activities of the long and the short heads of the biceps brachii were measured. The measured data were statistically processed using SPSS for Windows 12.0. For the activities of the short and the long heads according to the angle, a one-way ANOVA was conducted, and subsequently, to check the results of an analysis of the difference between groups, an LSD post-hoc test was conducted. An independent t-test was used to compare the activities of the long head and the short head according to the angles. Results: The analysis of the impact of the load of the dumbbell at each elbow angle on the muscle activities of the long and short heads of the biceps brachii revealed significant differences in both heads (p < 0.05). The result of the post-hoc analysis showed significant differences in both heads at angles between 0° and 30°, between 0° and 60°, and between 0° and 90°. Analysis of the impact of the load of the dumbbell in supination on the muscle activities of the long and short heads showed a significant difference at the angle between 0° and 30° (p < 0.05). Conclusion: The long head of the biceps brachii mainly acts in supination; however, in supination at elbow-bending angles of 60° and 90°, there was no difference in muscle activity between the short head and the long head.