• 정보과학회 컴퓨팅의 실제 논문지
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• 제23권7호
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• pp.434-439
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• 2017

수면장애로 고통을 받고 있는 사람들은 꾸준히 증가하고 있으며, 다양한 수면장애 원인이 존재한다. 따라서 수면장애를 겪고 있는 사람들에게 수면장애 원인을 진단하거나 수면상태 모니터링을 도와주는 수면 관련 헬스케어 산업이 각광받고 있다. 하지만 현재 서비스들은 모든 데이터를 원격지 서버로 전송해 서버에서 모든 것을 처리하는 단순 원격진료 서비스이기 때문에 데이터 집중현상에 취약하고, 원격지 피보호자의 다양한 생체 데이터를 동기화시켜 실시간으로 스트리밍하지 못한다는 단점이 있다. 이 문제를 해결하기 위해, 중앙 서버가 없는 자율군집형 분산 미들웨어 플랫폼을 이용하여 피보호자의 생체 데이터를 실시간으로 병원 혹은 보호자에게 스트리밍하는 서비스 구조를 제안한다. 제안하는 서비스 플랫폼의 기능 검증을 위해 스트리밍 요청에 따른 서비스 시작 소요시간과 평균 지연시간을 평가하고, 효과적인 스트리밍 서비스의 제공이 가능함을 확인하였다.

• Journal of Power Electronics
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• 제6권4호
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• pp.307-314
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• 2006

This paper presents a wavelet and neural network based technology for the monitoring and classification of various types of power quality (PQ) disturbances. Simultaneous and automatic detection and classification of PQ transients, is recommended, however these processes have not been thoroughly investigated so far. In this paper, the hardware and software of a power quality data acquisition system (PQDAS) is described. In this system, an auto-classifying system combines the properties of the wavelet transform with the advantages of a neural network. Additionally, to improve recognition rate, extraction technology is considered.

• 한국환경과학회지
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• 제3권4호
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• pp.305-315
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• 1994

The field observation was carried out to investigate the characteristics of surface inversion layer at Kimhae using the feild observed date and upper layer meteorological data during 4-5 February 1993. The results of the study can be summarized as follows : The maximum height of surface inversion layer observed at Kimhae is 193m and the height of upper level inversion layer ranges from 2nm to 300m. The surface weather elements was influenced the formation of surface inversion layer. According to the pasquill stability and time variation of temperature with height, both the surface heating from insolation and the disturbance of upper level of inversion layer was influenced the disappearance of inversion layer. And the stability of surface temperature inversion layer generally belongs to the class of F, that of upper level temperature inversion layer commonly to the class of E.

• 한국자동차공학회논문집
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• 제4권2호
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• pp.198-208
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• 1996

The plunge joints of C.V. Joint for vehicle tend to produce a cyclic axial disturbance at a frequency of three of six times shaft speed, in which this distrubance caused by internal frictional effect is related to joint angle, rotational speed, torque, and joint size. This principal axial thrust force might make vehicle shuddered when coinciding with vehicle frequency of tranverse direction, and be one of reasons to have driver feel uncomfortable, unesay, while driving vehicle. The paper makes analysis of axial thrust force & vehicle shudder through computer simulation, comparing the result with experimental data, and reviewing the effect by changing of variables such as dimensions and driving conditions.

• 제어로봇시스템학회논문지
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• 제11권3호
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• pp.262-269
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• 2005

Automatic landing of UAVs receives increasing interest these days, with increasing number of the developed UAV systems. In this paper, a glidepath tracking algorithm of the subscale UAV was proposed and the performance was analyzed. Flight data analysis shows that the existing autolanding flight control algorithm has a classical type glidepath control. This paper presents an alternative glidepath tracking strategy based on embedded flight control law. The performance of the proposed strategy was investigated through the TDP(Touch Down Point) error analysis with regard to various flight environment: steady headwind, atmospheric disturbance, communication transfer delay. It was verified that the proposed glidepath tracking strategy can be successfully applied to the practical autolanding of UAV systems.

• Journal of Electrical Engineering and Technology
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• 제8권3호
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• pp.472-477
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• 2013

An internet-based, real-time GPS synchronized wide-area power system frequency monitoring network(FNET) has been monitoring wide-area power system frequency in continuous time in the United States. This paper analyzes the FNET measurement to the verified disturbances in the US eastern interconnected power system and simulates it using the dynamic system model. By comparing the frequency measurements with its simulation results to the same disturbances in detail, this paper finds that the sequence of monitoring points to detect the frequency fluctuation caused by the disturbances is matched well in the measured data and the simulation results. The similarity comparison index is also proposed to quantify the similarity of the compared cases. The dynamic model based simulation result is expected to compensate for the lack of FNET measurement in its applications.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.538-543
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• 2003

Perforated wall has long been employed to control a variety of flow phenomena. It has been, in general, characterized by a porosity of the perforated wall. However, this porosity value does not take account of the number and detailed shape of porous holes, but is defined by only the ratio of the perforated area to total wall surface area. In order to quantify the porous wall effects on the flow control performance, an effective porosity should be known with the detailed flow properties inside the porous holes. In the present study, a theoretical analysis using a small disturbance method is performed to investigate detailed flow information through porous hole and a computational work is also carried out using the two-dimensional, compressible Navier-Stokes equations. Both the results are compared with existing experimental data. The gasdynamical porosity is defined to elucidate the effect of perforated wall.

• International Journal of Fluid Machinery and Systems
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• 제4권1호
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• pp.114-132
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• 2011

We have proposed a new approach based on energy gradient concept for the study of flow instability and turbulent transition in parallel flows in our previous works. It was shown that the disturbance amplitude required for turbulent transition is inversely proportional to Re, which is in agreement with the experiments for imposed transverse disturbance. In present study, the energy gradient theory is extended to the generalized curved flows which have much application in turbomachinery and other fluid delivery devices. Within the frame of the new theory, basic theorems for flow instability in general cases are provided in details. Examples of applications of the theory are given from our previous studies which show comparison of the theory with available experimental data. It is shown that excellent agreement has been achieved for several configurations. Finally, various prediction methods for turbulent transition are reviewed and commented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.581-583
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• 1995

This paper presents a theory on the pricing and allocation of spinning reserve. It is shown in this paper, that it is possible to maintain system security with many participants each attempting to optimize their own benefit, through pricing incentive. Participant offers power consumption/generation and reserve contribution according to its price. And Price setter only distribute pricing signal to acquire system security. Participants induce disturbance on power system and they pay the penalty according to the size of disturbance. And they also offers some reserve capacity to earn reserve cost. In this scheme, the amount of data communication is very small.

• 한국지반환경공학회 논문집
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• 제7권2호
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• pp.55-66
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• 2006

미국의 기존 고속도로인 LA-1 은 허리케인 대피 및 석유산업 등과 같은 수송수단에 대한 증가하는 지역적 요구를 해소하기 위해 교체되어야 할 필요가 있다. LA-1 고속도로 28km 구간은 습지를 가로지르며 예민한 지반으로 이루어져 있다. 본 지역에 대한 시료채취, 시료의 교란 그리고 시험 과정에서 있을 수 있는 고유의 오류들을 줄이기 위해 방대한 양의 지반조사 및 정밀한 실내시험을 수행하였으며 VFSF를 이용한 시료 운반은 지반에 대한 보다 정밀한 데이터를 얻을 수 있다.