• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제14권5호
• /
• pp.1967-1983
• /
• 2020

The goal of this paper is to analyze and build an algorithm to recognize hand gestures applying to smart home applications. The proposed algorithm uses image processing techniques combing with artificial neural network (ANN) approaches to help users interact with computers by common gestures. We use five types of gestures, namely those for Stop, Forward, Backward, Turn Left, and Turn Right. Users will control devices through a camera connected to computers. The algorithm will analyze gestures and take actions to perform appropriate action according to users requests via their gestures. The results show that the average accuracy of proposal algorithm is 92.6 percent for images and more than 91 percent for video, which both satisfy performance requirements for real-world application, specifically for smart home services. The processing time is approximately 0.098 second with 10 frames/sec datasets. However, accuracy rate still depends on the number of training images (video) and their resolution.

• 대한기계학회논문집
• /
• 제18권2호
• /
• pp.446-455
• /
• 1994

An experimental study is conducted for the turbulent recirculating flow behind a backward-facing step when the oscillating jet is issued sinusoidally through a thin slit at the separation edge. Two key parameters are dealt with in the present experiment, i.e., the amplitude of forcing and the forcing frequency. The Reynolds number based on the step height is varied from 25,000 to 35,000. In order to investigate the effect of local forcing, turbulent structures are scrutinized for both the flow of forcing and the flow of no forcing. The growth of shear layer with a local forcing is larger than that of no forcing. The influence of a local forcing brings forth the decrease of reattachment length and the particular frequency gives a minimum reattachment length. The most effective frequency depends on the non-dimensional frequency, St/sub .theta./, based on the momentum thickness at the separation point. A comparative study leads to the conclusion that the large-scale vortical structure is strongly associated with the forcing frequency and the natural flow instability.

• 전력전자학회논문지
• /
• 제3권4호
• /
• pp.418-425
• /
• 1998

본 논문에서는 위상각 제어에서 주어진 턴온 각에서 최대의 토크를 유지하기 위한 적절한 턴오프 각을 자기동조방식(self-tuning method)에 의해 결정하는 방식을 제안하였다. 엔코더에 의해 샘플링 시간(sampling time)동안 구해진 펄스 수는 바로 이전의 샘플링시간 동안 구해진 펄스 수와 비교하여 턴오프 각을 앞으로 또는 뒤로 이동한다. 이러한 과정을 되풀이함으로서 최대 토크를 발생하는 턴오프 각을 결정하게 된다. 실제 회로에서는 원 칩 마이크로프로세서에 의해 처리되었으며 실험을 통해 턴온 각이 변하더라도 자기동조방식에 의해 턴오프 각을 조정하면 빠른 속도가 유지됨을 보여 주었다.

• 한국정보처리학회논문지
• /
• 제7권4호
• /
• pp.1236-1245
• /
• 2000

This paper propose a novel scheme, called Mobiel Terminal Initiated Scheme(MTIS), in which mobile terminal initiates the backward handover by sending handover request message with the list of target radio ports. In this scheme, the old ATM switch suporting end-user mobility, denoted by EMAS\ulcorner, checks whether each EMAS\ulcorner, managing the target radio port, has its available resources. If it has, the EMAS\ulcorner performs the path rerouting between CrossOver Switch (COS) and itself after deciding the most suitable target radio port. Therefore, the MT initiates the handover after deciding the most suitable target radio port through the beacon signal of Wireless Access Point (WAP). The EMAS\ulcorner have only to check the resource availability of the target radio port. It is no need to waste time to decide the suitable target radio port. Also, once receiving the request of the resource availability, the EMAS\ulcorner can reduce the rerouting delay time due to perform the path rerouting to the COS. In comparison with that of the ATM-Forum procedure, our proposed MTIS handover delay time reduced 14~21%, and end-to-end transfer delay time reduced 2~9%, as a result of the simulation.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2005년도 연구개발 발표회 논문집
• /
• pp.776-781
• /
• 2005

Cavitation is the most serious problem caused in developing high-speed turbopump, and use of an inducer is often made to avoid cavitation in main impeller. Thus, the inducer always operates under the worst condition of cavitation. If it could be possible to control and suppress cavitation in the inducer by some new device, it would also be possible to suppress cavitation occurring in all types of pumps. The purpose of our present study is to develop a new effective method of controlling and suppressing cavitation in an inducer using shallow grooves, named as "J-Groove", J-Groove is installed on the casing wall near the blade tip to use the pressure difference between high pressure region and low pressure region in the axial direction at the inlet of the inducer. The results show that proper combination of backward-swept inducer with J-Groove improves suction performance of turbopump remarkably in the range of partial flow rate as well as designed flow rate. The rotating backflow cavitation occurring in the range of low flow rate and the cavitation surge occurring in the vicinity of the best efficiency point can be almost fully suppressed by installing J-Groove.

• 한국통신학회논문지
• /
• 제29권5A호
• /
• pp.484-491
• /
• 2004

L-band EDFA는 작은 평균밀도 반전율에서 동작하기 때문에 C-b란d에서 상대적으로 높은 흡수율로 인해 펌프 효과를 가지게 된다. 본 논문에서는 980nm의 펌프 입력 광 파워, C-band 펌프 파장 및 입력 광 파워에 따라 펌프 효과에 대해 논하고자 한다. 즉, C-band 펌프광의 흡수 또는 후방 자연방출광의 흡수라는 두 가지 다른 메카니즘을 통해 펌프 효과를 야기 시키게 된다. 또한 동일한 소 신호 이득 조건 하에서 L-band 신호 입력 광에 의한 포화 특성 (포화 광출력, 잡음지수에 있어서 장파장의 C-band 펌프가 양호한 것으로 나타난다. 전광 고정이득 L-band EDFA에서 C-band발진의 효과를 검토한 결과 L-band발진에 비해서 개선된 특성은 없는 것으로 나타난다.

• 대한기계학회논문집B
• /
• 제29권11호
• /
• pp.1239-1247
• /
• 2005

Cavitation is the most serious problem in developing high-speed turbopump, and inducer is often used to avoid cavitation in main impeller. Thus, inducer is always operating in the worst .cavitation condition. If it is possible to control and suppress cavitation in inducer by some new device, it might be possible to suppress cavitation occurring in any type of pumps. The purpose of present study is to develop a new effective method of controlling and suppressing cavitation in inducer using shallow grooves, which is named 'J-Groove'. J-Groove is installed on the casing wall near the blade tip to use the pressure difference between high pressure region and low pressure region of the inducer in an axial direction. The results show that proper combination of backward-swept inducer with J-Groove improves suction performance of turbopump remarkably in the range of partial flow rate as well as designed flow rate. The rotating backflow cavitation occurring in the range of low flow rate and the cavitation surge occurring in the vicinity of the best efficiency point can be almost suppressed by installing J-Groove.

• 대한의용생체공학회:의공학회지
• /
• 제30권3호
• /
• pp.247-254
• /
• 2009

We studied the postural response induced by plantar sole vibration with various frequencies(20, 60, 100Hz) and vibration zone(the anterior and posterior foot zone) of both soles during standing. Eight healthy young adults were exposed to 15s periods of plantar sole vibration while blindfolded. Body sway(COM, center of mass), the angle of neck, trunk, hip, knee, ankle and EMG of four lower limb muscles(tibialis anterior, lateral and medial gastrocnemial, soleus muscle) were recorded during 15s plantar sole vibration using 3D motion analysis system. Simulating each zone separately resulted in spatially oriented body tilts; oppositely directed backward and forward, respectively, the amplitude of which was proportional to the vibration frequency. EMG activity of lower limb muscles also varied according to the direction of the vibration zone and linearly according to the frequency. These findings led us to consider the plantar sole vibration as useful method of postural balance control and adjustment.

• 한국통신학회논문지
• /
• 제31권6A호
• /
• pp.547-555
• /
• 2006

본 논문에서는 고효율 증폭 기능을 가지는 이중경로증폭 구조의 고정이득 L-band EDFA를 구현하였다. 선형공진기로부터 생성된 발진광에 의해 신호채널들이 분기결합 되더라도 잔류채널의 요동을 줄일 수 있다. 잔류채널의 과도응답 특성에 대해 발진출력광 변화율이라는 정량적인 척도를 제시하였고 이를 이용해 발진파장 및 발진방향에 따른 과도응답 특성을 측정하였다. 결과적으로 단파장 및 펌프광의 반대 방향으로 전파하는 후방 발진광이 가장 양호한 것으로 판명되었다.

• 간호행정학회지
• /
• 제20권4호
• /
• pp.362-372
• /
• 2014

Purpose: The purpose of this research was to develop and test the validity and reliability of the Service Orientation Scale for Health Care Organization. Methods: The Service Orientation Scale for Health Care Organization, $SERV^*OR$, was developed through forward-backward translation methods. Internal consistency and reliability, construct and criterion validity were calculated using SPSS Statistics WIN 17.0. Survey data were collected from 283 clinical nurses in a general hospital in J province. Results: The Service Orientation Scale for Health Care Organization showed reliable internal consistency with Cronbach's ${\alpha}$'s for the total scale ranging from .85~.91. Factor loading of the 30 items on four sub-scales ranged from .67~.83. The sub scales were named service leadership, service system, customer focus, and service control. Item convergent and discriminant validity were also established for the Service Orientation Scale for Health Care Organization. Criterion validity showed a significant correlation with customer orientation. Conclusion: The findings of the study demonstrate that the Service Orientation Scale for Health Care Organization has satisfactory construct and criterion validity, and reliability and can be used to measure service orientation.