• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제2B권4호
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• pp.201-206
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• 2002

The paper presents the component parts and their models of the Switched Reluctance motor drive system with the angle position-current chopping control and with the fixed angle pulse width modulation control. The calculation of the parameters and the simulated models based on the MATLAB SIMULINK software package are introduced by a four-phase 816 structure prototype with the four-phase asymmetric bridge power converter. The simulation of the prototype in the course of starting is made by the simulated models at the different control strategies and the different given rotor speed.

• 로봇학회논문지
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• 제15권1호
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• pp.16-23
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• 2020

This paper describes an alignment algorithm that estimates the initial heading angle of AUVs (Autonomous Underwater Vehicle) for starting navigation in a sea area. In the basic dead reckoning system, the initial orientation of the vehicle is very important. In particular, the initial heading value is an essential factor in determining the performance of the entire navigation system. However, the heading angle of AUVs cannot be measured accurately because the DCS (Digital Compass) corrupted by surrounding magnetic field in pointing true north direction of the absolute global coordinate system (not the same to magnetic north direction). Therefore, we constructed an experimental constraint and designed an algorithm based on extended Kalman filter using only inertial navigation sensors and a GPS (Global Positioning System) receiver basically. The value of sensor covariance was selected by comparing the navigation results with the reference data. The proposed filter estimates the initial heading angle of AUVs for navigation in a sea area and reflects sampling characteristics of each sensor. Finally, we verify the performance of the filter through experiments.

• KSTLE International Journal
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• 제9권1_2호
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• pp.22-25
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• 2008

This paper investigated the wetting and adhesion property of undulated DLC film with surface morphology controlled for a reduced real area of contact. The undulated DLC Films were prepared by 13.56 MHZ radio frequency plasma enhanced chemical vapor deposition (r.f. PECVD) by using nanoscale Cu dots surface on a Si (100) substrate. FE-SEM, AFM analysis showed that the after repeated deposition and plasma induced damage with Ar ions, the surface was nanoscale undulated. This phenomenon changed the surface morphology of DLC surface. Raman spectra of film with changed morphology revealed that the plasma induced damage with Ar ions significantly suppressed the graphitization of DLC structure. Also, it was observed that while the untreated flat DLC surfaces had wetting angle starting ranged from $72^{\circ}$ and adhesion force of 333ni. Had wetting angle the undulated DLC surfaces, which resemble the surface morphology of a cylindrical shape, increased up to $104^{\circ}$ and adhesion force decreased down to 11 nN. The measurements agree with Hertz and JKR models. The surface undulation was affected mainly by several factors: the surface morphology affinity to cylindrical shape, reduction of the real area of contact and air pockets trapped in cylindrical asperities of the surface.

• 한국운동역학회지
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• 제15권4호
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• pp.169-179
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• 2005

In the 500m short track speed skating, the matter of who reaches the first corner first can important factor since each competitor races with all speed from the start to the first line. A filed study was attempted to kinematical estimation six female foreign skaters, who participated in the 500m female final round competition, and two Korea skates during the World Short track Skating Championship. The three dimensional motion analysis with DLT method was executed using four video cameras for analyzing the actual competition situation. In point of analyzing the actual competition situation, it is expected that skaters and coaches the effective informations, and the following conclusions are drawn; The elapsed time by phase in start motion of the foreign skaters appeared shorter those of Korea skaters, so the start training of Korea skaters should be strengthed. Also the displacement of C.G in the foreign skaters appeared shorter displacement than those of Korea skaters. Especially in the starting position, the foreign skaters are superior to Korea skaters in displacement of first(left) and next following stroke(right). The velocity of C.G and maximum velocity of skate blade of foreign skaters art faster than those of Korea skaters. And the foreign skaters show the superior early velocity change. Both of leaning body angle, and left and knee angle of the foreign skaters lead to positive point of having the propulsive force in the early starting position. Observing in the most prominent feature of foreign and Korea skaters in start phase, foreign skaters skate quickly the third stroke. These features of Korea skaters would appear disadvantage of location selection in entering the coner course.

• 한국콘텐츠학회논문지
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• 제13권7호
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• pp.131-140
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• 2013

여성복에 있어서 09/10년 시즌에 가장 주목할 만한 특징은 파워 숄더 룩이다. 파워 숄더 룩은 단순히 패션니스타들에서만이 아니라 당당히 스트리트 패션의 하나로 자리 잡았으며 파워 숄더 룩의 50%이상을 차지하는 재킷이 여성복의 핵심 아이템의 하나로 부활하면서 재킷의 어깨 각도는 0도에서 30도 이상까지 다양하게 나타난다. 다양한 어깨 각도 중 10도, 15도, 20도의 형태가 70%이상을 차지하고 있으며 패턴의 형태는 몸판의 어깨선을 자연스럽게 올리고 확장한 어깨변형 패턴, 어깨선과 함께 소매산 부분을 절개한 소매산 변형 패턴, 몸판과 소매가 연결된 패턴이 주를 이루고 있다. 파워 숄더 패턴 전개는 어깨 각도가 높아질수록 각이 시작되는 점이 목옆점에 가깝게 하고 어깨끝점이 확장되어야 소매의 외관형태가 편안하고 피트성이 좋아진다. 어깨 변형의 경우 앞뒤 진동선의 시작점인 어깨점과 소매산의 정점 부분의 선이 완만하게 이어지도록 S라인형태를 유지하는 것이 가장 중요하며 소매산의 ease분량이 일반 재킷 소매보다 많아야 파워 숄더 실루엣이 자연스럽게 연출된다. 소매변형 패턴은 중심쪽 소매의 소매산 높이는 기본소매 소매산높이의 1.5cm를 외곽 소매분량으로 처리한 것을 고려하여 소매산 높이를 설정하고 어깨 각이 커질수록 외곽소매의 소매산 폭을 크게 함으로서 소매의 어깨점이 목옆점 방향으로 휘지 않고 각이 선 파워 숄더가 완성된다. 소매변형과 소매와 몸판연결 패턴의 경우 어깨점과 상완이 연결되는 부분에 충분한 여유가 필요하며 어깨각도도 다른 형태에 비해 상대적으로 낮아 보인다. 이와 같이 파워 숄더 재킷 패턴은 패턴 제작시 디자인적인 요소를 충분히 감안한 패턴 설계와 함께 소매의 달림선 위치, 어깨너비, 어개 높이 확장량, 소매통의 여유량 등을 고려하여 제작하는 것이 바람직하다.

• The Journal of Korean Physical Therapy
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• 제24권6호
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• pp.414-418
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• 2012

Purpose: Muscle fatigue affects proprioception, and it causes problems in spinal stability. The purpose of this study was to examine the effect on the accuracy of reproducing the lumbar angles before lumbar exercise and after fatiguing isokinetic lumbar exercise. Methods: Thirty healthy adults participated in this study. Before induction of fatigue by exercise, the proprioception was measured by Biodex. Lumbar positions were passively maintained on stimulation position ($25^{\circ}$ flexion and $25^{\circ}$ extension), and back to the starting position. Subjects actively repositioned the remembered stimulation position, and error degrees between the stimulation position and reposition were measured. Using an isokinetic device at $120^{\circ}$/sec of velocity of angle lumbar flexion/extension exercise resulted in muscle fatigue. The post-fatigue proprioceptive position sense was used in the same way as in pre-fatigue measurement. Results: Means of position sense of pre-fatigue were $2.19{\pm}1.97$ on flexion angle, and $5.04{\pm}2.84$ on extension angle. After exercise induced fatigue, means of position sense were $2.37{\pm}1.83$ on flexion angle, and $4.93{\pm}2.57$ on extension angle. Results of this study showed significant differences of lumbar proprioceptive position sense between pre- and post-fatigue. Conclusion: Lumbar proprioception sense in active repositioning in flexion and extension was affected in the presence of muscle fatigue. Therefore, it should be noted that therapeutic exercise for patients with abnormal proprioceptive sense or elderly people must be performed with care because muscle fatigue can cause secondary damage.

• 한국안전학회지
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• 제30권5호
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• pp.74-79
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• 2015

The purpose of this study is to find out its effect on changes in the joint angle and the success rate of cardiopulmonary resuscitation by conducting cardiopulmonary resuscitation (CPR) when wearing and not wearing PPE (personal protective equipment) targeting 20 paramedics with more than 5 years of experience. The subjects carried out CPR in 30:2 for 4 minutes and collected images were digitized by Kwon3D XP Software Package(Version 4.0) and then data were obtained. Data, which were collected by analyzing the motion when starting in one cycle, when pressing to the maximum, in the final position (relaxed), were analyzed by using SPSS 18.0. In conclusion, during CPR, the angle of the both shoulder joints was not significant (p>.05) and the angle of the right elbow joint was reduced in all positions and was statistically significant (p<.05) and the angle of the left was significantly reduced in the maximum pressure posture and the final position (p>.05). In the case of the trunk, the angle increased statistically significantly at all stages (p<.01, p<.001). Also, during CPR, the average compression rate was significantly reduced after wearing PPE (p<.05) and average hand escape time by cycle increased statistically significantly (p<.05) but chest compression execution rate at the correct depth did not show any significant difference between the two groups (p>05).

• 한국전문물리치료학회지
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• 제4권3호
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• pp.34-44
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• 1997

The purpose of this study was to compare the balance ability at different foot angle with KAT 2000 (Breg, Inc., Vista, CA. 1994). Forty-nine (male 24, female 25) normal subjects participated in this study. All subjects were assessed under two conditions. One was eye-opened condition and the other one was eye-closed one in 3 psi surface condition. All subjects were tested at different foot angle that were toe-in $25^{\circ}$, $45^{\circ}$, toe-out $25^{\circ}$ and $45^{\circ}$. The subject attempted to keep the platform as stable as possible with eyes closed and with eyes opened for every 20 seconds. The starting position was that subject crossed their arms across chest and flexed knees slightly. The results of each test were showed by a score on screen, which meant balance index. The se collected data were analyzed by using oneway ANOVA, Scheffe test, and t-test. The results of this study were as follows: 1. When the foot angle were changed, balance index was the lowest in toes-out $25^{\circ}$ condition and greatest with toes-in $45^{\circ}$ with eyes opened and with eyes closed. There were statistically significant difference with eyes opened and with eyes closed (p<0.05). 2. There was statistically significant difference in balance index according to visual condition and the balance index tested with eyes closed was higher than with eyes closed(p<0.05). 3. There was statistically significant difference in balance index by gender(p<0.05).

• 한국유체기계학회 논문집
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• 제19권1호
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• pp.37-44
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• 2016

In this study, a parametric study of a centrifugal pump with double volute has been performed numerically using three-dimensional Reynolds-averaged Navier-Stokes equations. The shear stress transport model was selected as turbulence closure through turbulence model test. The finite volume method and unstructured grid system were used for the numerical analysis. The optimal grid system in the computational domain was determined through a grid dependency test. The expansion coefficient, circumferential and radial starting positions and length of divider were selected as the geometric parameters to be tested. And, the hydraulic efficiency and the radial thrust coefficient were considered as performance parameters. It was found that the radial thrust and hydrualic efficiency are more sensitive to the expansion angle and circumferential starting position of the divider than the other geometrical parameters.

• Korean Chemical Engineering Research
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• 제54권3호
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• pp.387-393
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• 2016

불소가 함유된 폴리우레탄 코팅 용액을 과불화 알코올, toluene diisocyanate와 polycarbonate diol을 출발물질로 사용하여 합성하였다. 이렇게 합성된 불소 함유 폴리우레탄 코팅 용액을 기재인 PC 위에 스핀 코팅 후 $120^{\circ}C$에서 열경화시켜 코팅 필름을 제조하였다. 제조된 코팅 필름의 물성을 FT-IR spectroscopy, UV-visible spectrometer, 접촉각 측정기와 연필경도 측정기를 사용하여 분석하였다. 과불화 알코올의 첨가는 코팅 필름의 발수성을 향상시켜, 물 접촉각을 $81^{\circ}C$에서 $111^{\circ}C$로 증가시켰다. 그러나 코팅 필름의 연필경도는 과불화 알코올의 첨가에도 불구하고 H로 일정하였다.