• 정보처리학회논문지B
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• 제12B권3호
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• pp.273-282
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• 2005

실시간 객체 추적(Real-time object tracking)은 비디오 감시 시스템, 비전 기반 네비게이터와 같은 비전 응용 산업이 발달하면서 그 중요성이 더해지고 있는 분야이다. 객체 추적을 위해 많이 이용되고 있는 알고리즘으로 Mean-shift와 Condensation 알고리즘이 있다. Mean-shift 알고리즘을 기반으로 한 객체 추적 알고리즘은 구현이 간단하고, 적은 계산 복잡도를 갖는 장점이 있다. 따라서 실시간 객체 추적 시스템에 적합하다고 할 수 있지만, 지역 모드(Local mode)로 수렴하는 특성으로 인해 복잡한 환경(Cluttered environment)에서는 좋은 성능을 나타내지 못하는 단점을 가지고 있다. 반면, 여러 개의 후보들을 이용해 객체의 위치를 추정하는 Condensation 추적 알고리즘은 복잡한 환경에서 특정 객체를 추적하는데 많이 사용된다. 하지만 Condensation 알고리즘을 기반으로 한 추적 알고리즘은 정확한 추적을 하기 위해서 복잡도가 높은 객체 모델과 많은 수의 후보가 요구된다. 따라서 높은 복잡도를 갖게 되고, 이것으로 인해 복잡한 환경에서는 실시간 구현이 어렵다는 단점을 갖게 된다. 본 논문에서는, 복잡한 환경에서 실시간 객체 추적에 적합하도록 Condensation 알고리즘과 Mean-shift 알고리즘을 결합해서, 적은 수의 후보들을 이용하는 모델을 제안한다. 적은 수의 후보들을 이용하더라도, Mean-shift 알고리즘을 이용해 보다 높은 유사도를 가지는 후보들만을 이용함으로써, Condensation 알고리즘이나 Mean-shift 알고리즘만을 이용할 때보다 더 나은 성능을 얻을 수 있었다.

• 대한감각통합치료학회지
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• 제5권1호
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• pp.31-40
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• 2007

Objective: The purpose of this study was to get the cognitive reaction time according to the intensity of auditory stimuli in older people and to differentiate the cognitive reaction time between older people and adults. Method: 49 subjects consisted of 32 older people and 17 adults. Cognitive reaction time was assessed with Simple Auditory Reaction of Foundation I in PSS CogReHab. Analysis of the data was done by using independent t-test. Results: The results were as follows: 1. There was a significant difference of the mean of cognitive reaction time to the intensity of auditory stimuli. 2. There was no significant difference from older people regardless of sexual distinction in mean of cognitive reaction time. However, there was a significant difference of the mean of cognitive reaction time in adults. 3. There was a significant difference between older people who got a job or not in 90 dB of auditory stimuli. 4. The mean of cognitive reaction time to the intensity of auditory stimuli in older people was slower than adults. There was a significant difference of the mean of cognitive reaction time between older people and adults in 70 dB of auditory stimuli. 5. The mean of cognitive reaction time to the intensity of auditory stimuli in older people did not have the significant difference in scholastic ability. Conclusions: The results of the study showed slowing of the cognitive reaction time in auditory stimuli to aging in older people. Therefore, applying silver industry and development of equipment for older people may maintain independent life.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.44.3-44
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• 2002

Stability robustness of a linear time-varying system with time-varying structured state space uncertainties is considered by using extended-mean theorem and Bellman's lemma. The extended-mean theorem is a necessary and sufficient exponential stability criterion based on the recently developed PD-eigenvalue and PD-eigenvector for a linear time-varying system. Our new result required that the extended-mean of each nominal PD-eigenvalue should be negative real which is determined by a norm involving the structures of the uncertainty and the no...

• 한국해양공학회지
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• 제32권5호
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• pp.333-340
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• 2018

This paper addresses the concept of the representative mean position, which was devised to improve the numerical efficiency of a time domain fatigue analysis of a mooring chain. To investigate the influence of an artificial offset of the floater on the fatigue of the mooring chain, a parametric study was performed on the moored FPSO under various combinations of offsets and environmental conditions. Tension time histories were calculated using the de-coupled analysis method, and fatigue damages were calculated to determine the influence of the offset. The parametric study was extended to a more realistic case to determine the actual effect of the representative mean position, where a comparison was made between the two different analysis results, one using the representative mean position and the other one using the actual mean position. It was confirmed that the application of the representative mean position guaranteed the conservatism of the fatigue damage with the enhanced numerical efficiency in the time domain fatigue analysis.

• 한국수자원학회논문집
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• 제41권12호
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• pp.1199-1210
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• 2008

유역에서 물의 평균체류시간은 강우에 의해 토양에 강우 등으로 인해 수분이 침투하여 유출되기까지 소요되는 평균 시간이며, 침식, 식생분포, 유출기작 등을 지배하는 수문학적 과정을 이해하는데 중요한 요소이다. 물의 평균체류 시간을 산정하는 대표적인 방법인 방사성 동위원소에 의한 추적자법은 계산과정이 복잡하고 많은 비용이 들면서도 간접적인 방법임으로, 본 연구에서는 토양수분의 거동을 관측해 산지사면에서 물의 평균체류시간을 산정하는 보다 직접적인 방법을 고안하였다. 토양수분의 측정을 위해 광릉 국립수목원에 위치한 산림 소유역에 토양 수분 측정장비인 TDR을 설치하고 1년 동안 2시간 간격으로 깊이별 측정을 수행하였다. 토양수분을 이용해 산정된 물의 체류시간은 대상유역의 불투수 지하면에 가까워질수록 상승하는 경향을 보였고 강우가 집중된 여름에 가장 짧은 것으로 나타났다. 실험에서 얻어진 평균체류시간은 기존의 화학적 방법을 통해 산정된 값과 유사한 경향을 보였는데 이러한 결과들은 토양수분의 측정과 분석을 통한 방법이 방사성 동위원소를 이용한 방법보다 더욱 효율성 있는 측정을 할 수 있다는 것을 나타낸다.

• International Journal of Air-Conditioning and Refrigeration
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• 제10권4호
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• pp.177-183
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• 2002

A pulsed tracer gas technique is applied to measure the distributions of local mean age and local mean residual-life-time of air in a half-scale experimental chamber, The airflow patterns in the chamber are visualized by a Helium bubble generator for three different exhaust locations. A supply slot is located at the top of a right wall, and an exhaust slot is at either bottom-left (Case 1), bottom-right (Case 2), or top-left (Case 3) location. Results show that the distributions of local mean age and local mean residual-life-time are different from each other, but both of them are closely related to the airflow pattern in the space. Included are discussions on explaining the variations of overall room ventilation effectiveness depending upon airflow rates for three different supply-exhaust configurations.

• Journal of Positioning, Navigation, and Timing
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• 제3권4호
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• pp.143-147
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• 2014

The mean temperature is one of the key parameters in computing Precipitable Water Vapor (PWV) from Global Positioning System (GPS) measurements and is usually derived as a function of surface temperature through the use of a mean temperature equation (MTE). In this study, two new types of MTEs were developed as functions solely of the observation time so that the mean temperature can be obtained without surface temperature measurements. To validate the new models, we created one-year time series of GPS-derived PWV using the new MTEs and compared them with the radiosonde-observed PWV. The bias and root-mean-square error were on the other of ~1 mm and ~2 mm, respectively.

• 한국통신학회논문지
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• 제22권11호
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• pp.2401-2408
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• 1997

The measured pulse shapes provided in the given data package demonstrated pulse distortions due to laser speckle. the distorted pulse shapes were carefully analyzed, modeled, and then applied to the DTTL(Digital-data Transition Tracking Loop)[1] bit synchronizer simulator to measure the mean time delay and its delay variation performance. The result showed that the maximum mean time delay variation with the modeled data was 12.5% when window size equals 1. All the data given were located within this modeled boundary and the maximum eman time delay variation was 7% in this case. The mean time delay variation was known to be smaller by reducing the window size [2][5][6]. The mitigated delay variation was 2.5% in the modeled case and 1.4% in the data set given when the windown size equals 0.1. With the digital DTTL insteal of analog DTTL, similar results was obtained.

• 설비공학논문집
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• 제10권6호
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• pp.658-665
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• 1998

This paper investigates local exhaust effectiveness in a room with a supply and an exhaust slots on the ceiling. The mean age of air is an indicator of supply effectiveness, while the mean residual life time can be used as an indicator of exhaust effectiveness. The distribution of local mean residual life time in a space is calculated by four different numerical procedures. The reverse-flow calculation method has been proved to show quite accurate results while it can save considerable amount of computation time and efforts, compared to the method by its original definition. It is concluded that the diffusion term in the equation of mean residual life time can be neglected. The spatial and temporal diffusion characteristics of the contaminant are also discussed.

• 대한방사선기술학회지:방사선기술과학
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• 제20권1호
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• pp.35-38
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• 1997

Scintigraphic measurement of gastric emptying time has been reported to be influenced by the variation in depth of radionuclide within the stomach. This study was designed to clarify whether a part of the variability in gastric emptying could be ascribed to a relationship between anterior image, the total anteroposterior Image and the tissue attenuation correction(geometric mean). A dual-head scintillation camera(ADAC, USA) was used to investigate effect of such changes. We were performed 16 normal subject gastric emptying studies with $^{99m}TC$ labelled scramble egg, milk and solid meal(610 Kcal, 300 g) The results are as follows; On anterior Image, $T_{1/2}$ emptying time was delayed by 5 min, 6.5%(range $3{\sim}18\;min,\;5{\sim}31.4%$) compared with the geometric mean. But there was no different gastric emptying time between the total anteroposterior image and geometric mean. Therefore, if will be useful to use the method of geometric mean or the total anteroposterior image to evaluate the gastric emptying time accurately.