• Journal of Chest Surgery
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• 제57권5호
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• pp.477-483
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• 2024

Background: Torsion of the right middle lobe following right upper lobectomy is a rare but potentially fatal complication. To prevent this, fixation of the right middle lobe has been suggested. This study was performed to examine the impact of right middle lobe fixation on postoperative outcomes and bronchial changes. Methods: We enrolled patients who underwent curative-intent video-assisted thoracic surgery (VATS) right upper lobectomy for lung cancer from 2019 to 2022. Participants were grouped based on whether they did or did not receive right middle lobe fixation. Bronchial angles were measured using preoperative and postoperative chest computed tomography images, and postoperative outcomes and bronchial changes were compared between the 2 groups. Results: The study included a total of 50 patients, with 17 (34%) undergoing right middle lobe fixation. All procedures were performed using VATS. No significant differences between groups were observed in preoperative characteristics or postoperative outcomes. After surgery, both groups exhibited a significant increase in the right bronchus intermedius angle and a significant decrease in the branch angle. The postoperative right bronchus intermedius angle was significantly larger in the group without right middle lobe fixation compared to the group with fixation (47.38°±10.98° vs. 39.41°±9.21°, p=0.014). Three cases of atelectasis occurred in the group that did not undergo fixation while no cases were observed in the fixation group; however, this difference was not statistically significant. Conclusion: Fixation of the right middle lobe reduced postoperative angulation of the right bronchus intermedius, which may help prevent postoperative atelectasis.

• 대한기계학회논문집A
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• 제26권5호
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• pp.914-923
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• 2002

Recently, there has been considerable interest in micro gyroscopes made of silicon chips. It can be applied to many micro-electro-mechanical systems (MEMS): devices for stabilization, general rate control, directional pointing, autopilot systems, and missile control. This paper shows how the mechanical design of the gyroscope can be done using axiomatic design, followed by the application of the Taguchi robust design method to determine the dimensions of the parts so as to accommodate the dimensional variations introduced during manufacturing. Functional requirements are defined twofold. One is that the natural frequencies should have fixed values, and the other is that the system should be robust to large tolerances. According to the Independence Axiom, design parameters are classified into a few groups. Then, the detailed design process is performed fellowing the sequence indicated by the design matrix. The dimensions of the structure are determined to have constant values fur the difference of frequencies without consideration of the tolerances. It is noted that the Taguchi concept is utilized as a unit process of the entire axiomatic approach.

• 대한기계학회논문집
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• 제15권6호
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• pp.1831-1838
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• 1991

본 연구에서는 와핑과 두 단면중심의 불일치에 의해 발생하는 기하중심의 이 동을 고려한 등매개변수보요소를 개발하여 스프링단면의 응력해석을 수행하고 그 결과 를 다음과 같이 검증할 것이다.우선 본 연구에 사용된 보요소가 이 두 효과를 효과 적으로 표현하고 있는지를 확인하기 위해서 간단한 비틀림실험과 비교할 것이다. 또 한 2차원문제에 대해서 입체요소를 이용한 결과와 비교하고, 원통형 스프링모델의 해 석결과를 Nagaya의 해석결과와 비교함으로써 실제 스프링해석에 효과적으로 적용될 수 있음을 보일 것이다.

• 조명전기설비학회논문지
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• 제17권6호
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• pp.138-146
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• 2003

본 논문에서는 직접적인 방법으로는 산불로 인한 전선의 열화특성을 분석하기 어려우므로 인공화염장치를 이용하여 건전 전선을 일정 시간 간격으로 화염을 가하는 실험을 하였다. 기계적 실험은 인장강도, 연신율 및 비틀림 수 실험을 수행하였다. 또한, 포항지역에 가설되어 운전 중이던 ACSR 480[$\textrm{mm}^2$]가 산불 열화로 인하여 철거된 전선을 수거하여 기계적 특성 시험 및 분석결과와 인공화염장치를 이용한 실험결과를 비교$.$분석하였다. 이 두 개의 분석 자료를 이용하여 향후 산불에 의해 열화된 전선의 상태를 예측할 수 있는 데이터베이스를 만들고, 또한 산불로 인한 ACSR 전선의 수명 진단에 필요한 자료를 제공하고자 한다.

• 한국정밀공학회지
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• 제31권10호
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• pp.913-922
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• 2014

This paper describes design of a robotic above-knee prosthetic leg which is powered by electrical motors. As a special feature, the robotic prosthetic leg has enough D.O.F.s. For mimicking the human leg, the robotic prosthetic leg is composed of five joints. Three of them are called 'active joint' which is driven by electrical motors. They are placed at the knee-pitch-axis, the ankle-pitch-axis, and the an! kle-roll-axis. Every 'active joint' has enough torque capacity to overcome ground reaction forces for walking and is backlashless for accurate motion generation and high-performance balance control. Other two joints are called 'passive joint' which is activating by torsion spring. They are placed at the toe part and designed by Crank-rocker mechanism using kinematic design approach. In order to verify working performance of the robotic prosthetic leg, we designed a gait trajectory through motion capture technique and experimentally applied it to the robot.

• 한국기계가공학회지
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• 제12권4호
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• pp.69-74
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• 2013

According to the axial torsion applied at power transmission and the vibration from the roughness of road surface, this paper analyzes the stresses on two kinds of universal joint model. As stress and deformation at model 2 becomes smaller than model 1 on structural analysis, model 2 is more stabilized than model 1. The natural frequencies at model 1 and 2 are 7,040 and 9,540 Hz respectively. As the natural frequency range of model 2 becomes higher than model 1, model 2 becomes safer than model 1. Critical frequencies at these models are calculated through harmonic response analyses. On critical frequencies at model 1 and 2, the stress at model 2 becomes lower than 2 times as much as model 1 and the deformation at model 2 becomes lower than 4 times as much as model 1. Model 2 on durability is thought to become better than model 1. This study result is applied with the design of safe universal joint and it can be useful to improve the durability by predicting prevention against the deformation due to its vibration.

• 한국생산제조학회지
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• 제22권6호
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• pp.969-975
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• 2013

While accelerating, bicycle frames are subject to torsion forces and deformation. In this study, bicycle frame durability was evaluated by using structural, fatigue, and vibration experiments. Three types of models were designed by changing the frame configurations according to the shape and direction of a bicycle frame design. Because maximum equivalent stress was greatest at the saddle and at connected parts in Models 1, 2, and 3, these frame sections were most vulnerable to failure. Model 2 was the least safe, due to the increased total deformation and equivalent stresses in the top tube horizontal to the ground. Based on vibration and fatigue analysis results, Model 2 was also determined to be the least safe frame, because the head tube was placed slightly higher above the seat tube and inclined to $10^{\circ}$. These study results can be utilized in the design of bicycle frames by investigating prevention and durability against damage.

• 한국자동차공학회논문집
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• 제16권4호
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• pp.135-142
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• 2008

Hydraulic power steering system has been adopted in seniority passenger and commercial vehicle system for an easy maneuverability and a smoother ride. In this study, hydraulic power steering system analysis model which includes hydraulics and mechanical sub-systems was developed using commercial software, AMESim in order to predict characteristics for various steering components. Each component which constructs system was modeled and verified by experimentally obtained characteristics curves of each components. The parameter sensitivity analysis such as valve opening area, torsional stiffness of torsion bar for system design are carried out by the analysis and experimental method. The predicted results by the development model were a good agreement with experimentally obtained results. The sensitivity investigation results rotary torque when changing an input shaft edge width, was most sensitive, to change in angle and slot width and supply flow of input shaft edge is not a lot sensitively.

• 한국해양공학회지
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• 제24권4호
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• pp.72-77
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• 2010

This paper presents a method for measuring the shaft power of a marine main engine. Usually, in traditional systems for measuring shaft power, a strain gauge is used even though it has several disadvantages. First, it is difficult to set up the strain gauge on the shaft and acquire the correct signal for analysis. Second, it is very expensive and complicated. For these reasons, we investigated alternative approaches for measuring shaft power and proposed a new method that uses a vision-based measurement system. For this study, templates for image processing and CCD cameras were installed at the both ends of the shaft. Then, in order for the cameras to capture the images synchronously, we used a trigger mark and a optical sensor. The position of each template between the first and the second camera images were compared to calculate the torsion angle. The proposed measurement system can be installed more easily than traditional measurement systems and is suitable for any shaft because it does not contact the shaft. With this approach, it is possible to measure the shaft power while a ship is operating.

• 대한기계학회논문집A
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• 제30권8호
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• pp.897-905
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• 2006

This study considers an experimental design of disturbance compensation control to improve stabilization performance of main battle tanks. An adaptive non-parametric design technique based on the Filtered-x Least Mean Square(FXLMS) algorithm is applied in the consideration of model uncertainties. The optimal compensator is designed by two-step design procedures: determination of frequency response function of the disturbance compensator which can cancel the disturbance of series of single harmonics by using the FXLMS algorithm and determination of the compensator polynomial which can fit the frequency response function obtained in the first step optimally by using a curve fitting technique. The disturbance compensator is applied to a simple experimental gun-torsion bar-motor system which simulates gun driving servo-system. Along with experimental results, the feasibility of the proposed technique is illustrated. Experimental results demonstrate that the proposed control reduces the standard deviation of stabilization error to 47.6% that by feedback control alone. The directional properties of the FXLMS Algorithm such as the direction of convergence and its convergence speed are also verified experimentally.