• 한국컴퓨터정보학회논문지
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• 제18권8호
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• pp.65-75
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• 2013

본 논문에서는 깊이 영상만을 이용하여 손 영역 추적 및 손 끝점 검출 방법을 제안한다. 조명 조건의 영향을 제거하고 빠르고 안정적인 정보 획득을 위해 깊이 정보만을 이용하는 추적 방법을 제안하고, 영역 확장 방법을 통해 추적 과정 중에 발생할 수 있는 오류에 대한 판단 방법과 다양한 제스처 인식에 응용이 가능한 손 끝점 검출 방법을 제안한다. 먼저 추적점을 찾기 위해 중심점 전이 과정을 통해 최근접점을 찾고 그 점으로부터 영역 확장을 통해 손 영역과 경계선을 검출한다. 그리고 영역 확장을 통해 획득한 무효경계선의 비율을 이용하여 추적영역에 대한 신뢰도를 계산함으로써 정상 추적 여부를 판단한다. 정상적인 추적인 경우, 검출된 손 영역으로부터 윤곽선을 추출하고 곡률 및 RANSAC, 컨벡스 헐(Convex-Hull)을 이용하여 손 끝점을 검출한다. 마지막으로 성능 검증을 위해 다양한 상황에 따른 정량적, 정성적 분석을 통해 제안하는 추적 및 손 끝점 검출 알고리즘의 효율성을 입증한다.

• 대한인간공학회지
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• 제31권4호
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• pp.601-607
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• 2012

Objective: The aim of this study is to classify between intentional and natural blinks in vision based eye tracking system. Through implementing the classification method, we expect that the great eye tracking method will be designed which will perform well both navigation and selection interactions. Background: Currently, eye tracking is widely used in order to increase immersion and interest of user by supporting natural user interface. Even though conventional eye tracking system is well focused on navigation interaction by tracking pupil movement, there is no breakthrough selection interaction method. Method: To determine classification threshold between intentional and natural blinks, we performed experiment by capturing eye images including intentional and natural blinks from 12 subjects. By analyzing successive eye images, two features such as eye closed duration and pupil size variation after eye open were collected. Then, the classification threshold was determined by performing SVM(Support Vector Machine) training. Results: Experimental results showed that the average detection accuracy of intentional blinks was 97.4% in wearable eye tracking system environments. Also, the detecting accuracy in non-wearable camera environment was 92.9% on the basis of the above used SVM classifier. Conclusion: By combining two features using SVM, we could implement the accurate selection interaction method in vision based eye tracking system. Application: The results of this research might help to improve efficiency and usability of vision based eye tracking method by supporting reliable selection interaction scheme.

• 한국정밀공학회지
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• 제23권1호
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• pp.121-128
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• 2006

This paper deals with the application of enhanced perturbation estimation (SMCEPE) to sliding mode control of a dynamic system in the presence of perturbations including external disturbances, unpredictable parameter variations, and unstructured dynamics. Compared to conventional sliding mode control (SMC) and sliding mode control with perturbation estimation (SMCPE), the proposed one can offer robust control performances under serious control conditions, such as fast dynamic perturbations and slow loop-closure speeds, without a priori knowledge on upper bounds of perturbations. The perturbation estimator in SHCEPE also has more adaptability owing to the fractional-order hold technique. The effectiveness and superiority of the proposed control strategy are demonstrated by a series of simulations on the position tracking control of a two-link robot manipulator.

• 대한기계학회논문집A
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• 제29권11호
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• pp.1455-1462
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• 2005

In this paper, we intend to introduce a nonlinear finite element method based on the fully nonlinear potential flow theory in order to simulate the large amplitude sloshing flow in two-dimensional baffled tank subject to horizontally forced excitation. The free surface is tracked by a direct time differentiation scheme with the four-step predictor-corrector time integration method. The flow velocity is accurately recovered from the velocity potential by second-order least square method. In order to maintain the finite element mesh regularity and total mass, the semi-Lagrangian surface tracking method with area conservation is applied. According to the numerical formulae, we perform the parametric experiments by varying the installation height and the opening width of baffles, in order to examine the effects of baffle on the nonlinear liquid sloshing. From the numerical results, the hydrodynamic characteristics of the large amplitude sloshing are investigated.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.609-615
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• 2001

A turbo-fan is easily exposed to noise and vibration as against other industrial machines and the majority of them is subject to be damaged by vibration. The most usual problem of vibration in a turbo-fan is resonance so the case of being composed of iron sheet structure with low strength like a turbo-fan should be taken seriously. In this paper, FFT(Fast Fourier Transform) and Order tracking method were used to analyze factors of vibration in a turbo-fan and hereby with proper selection of vibration isolator, we wanted to reduce vibration of base. After Order tracking, we knew resonance occurred in rotational frequency 23 Hz(1400 rpm) at the casing and the bearing. After the test of base vibration using vibration isolators, the spring isolator was more effective than the robber isolator in the base vibration and the vibration isolating is more effective in the case that the isolating pad is adhered to the bottom of the isolating spring.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.513-517
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• 2005

The condition monitoring of rotating machinery such as turbines, pumps and compressors, determine what repairs are needed to avoid shutdown and disassembly of the machine in an industrial plant Many diagnosis methods have been developed for use when the machine is running at steady state, the stationary condition. But much information can be gained about a rotor's condition during non-stationary conditions such as run-up and run-down. Order tracking analysis is a powerful tool for analyzing the condition of a rotating machine when its speed changes over time. Powerful OTA using digital signal processing has some advantages(cheap hardware, the powerful methods, the accurate post processing) and also some disadvantages(calculation time, high speed sampling). New OTA tool based on the chirplet transform is similar to the short time Fourier transform. But, it has good resolution at high speed like other OTA methods based STFT and more resolution for constant frequency components than re-sampling OTA.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권5호
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• pp.302-309
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• 2000

The tracking characteristics of silicone rubber degraded by accelerated outdoor exposure employing a weather-o-meter were investigated. The tracking test was performed according to ICE Publ.587 method but the concentration of conductive solution was two times higher than IEC standard in order to accelerate the tracking failure. The number of large effective scintillation and the current of high voltage circuit were measured simultaneously. It was shown that the number of effective scintillation had valuable information of the tracking degradation state of silicone rubber, while the average current between electrodes could not provide information enough for diagnosis. Based upon the experimental results, it could be said that the key factor accelerating tracking failure was not Joule heating by current but pyrolysis by burning of silicone rubber, and that reduction of contact angle was due to chain scission which resulted in the free radicals of low molecules.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1235-1238
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• 1995

Electrical property of polymeric insulating plays a key role in the trend of making power apparatus high voltage, and reliability and safety of apparatus in the long term depend on it. There is a recent trend of applying polymeric material to insulating material for outdoor, and particularly it is expected that it may be used partly as a pin insulator. Using as an alternate of insulating material for outdoor, however, it has still many problems to be solved in the field of material such as resistances of environment and tracking. It has been given attention to that the silicon rubbers and the epoxy have recently been used. but the the reliability in the viewpoint of material property becomes an issue. The polymeric materials such as EPDM, Epoxy and PVC have also been used as an insulating materials for outdoor. In this point of view, we studied each tracking phenomenon with test material such as rubber for pin, PVC for powercable used as an insulating material for outdoor, and Epoxy etc. The characteristics of anti tracking shows EPDM>Epoxy>PVC in order in the results. We also know that there is an close relationship between properties of tracking and thermegravimetry.

• 한국멀티미디어학회논문지
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• 제19권2호
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• pp.418-427
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• 2016

A smart parking management requires to track a vehicle in a indoor parking lot and to detect the place where the vehicle is parked. An advanced parking system watches all space of the parking lot with CCTV cameras. We can use these cameras for vehicles tracking and detection. In order to cover a wide area with a camera, a fisheye lens is used. In this case the shape and size of an moving vehicle vary much with distance and angle to the camera. This makes vehicle detection and tracking difficult. In addition to the fisheye lens, the vehicle headlights also makes vehicle detection and tracking difficult. This paper describes a method of realtime vehicle detection and tracking robust to the harsh situation described above. In each image frame, we update the region of a vehicle and estimate the vehicle movement. First we approximate the shape of a car with a quadrangle and estimate the four sides of the car using multiple histograms of oriented gradient. Second we create a template by applying a distance transform to the car region and estimate the motion of the car with a template matching method.

• 한국군사과학기술학회지
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• 제20권1호
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• pp.108-118
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• 2017

In this paper, the path tracking controller for a surface vessel based on the sliding mode control (SMC) with the switching law is proposed. In order to have no restriction on movement and improved tracking performance, the proposed control system is developed as follows: First, the kinematic and dynamic models in Cartesian coordinates are considered to solve the singularity problem at the origin. Second, the new multiple sliding surfaces are designed with the SMC and approach angle concept to solve the under-actuated property. Third, the switching control system is designed to improve tracking performance. To prove the stability of the proposed switching system under the arbitrary switching, the Lyapunov stability analysis method with the common Lyapunov function is used. Finally, the computer simulations are performed to demonstrate the performance, effectiveness and stability of the proposed tracking controller of a surface vessel.