• 한국항행학회논문지
• /
• 제17권6호
• /
• pp.616-624
• /
• 2013

전파 교란신호가 발생할 경우, GPS 기반의 정밀위치제공시스템에 오작동을 일으킬 수 있으며 특히, 항공분야에서는 더 심각한 피해가 발생할 수 있다. 하나의 전파교란원에 대한 대응 기법이나 위치 추정 기법의 연구결과는 잘 알려져 있으나, 다수의 전파교란원이 다양한 형태의 신호를 송출할 경우에는 대응 및 위치 추정이 어렵다. 따라서 본 논문에서는 다수의 전파위협원이 CW, DSSS, SCW 형태의 신호를 송출할 경우에 위치 추정을 수행할 수 있도록 하기 위하여 신호 식별 및 측정치 획득 방법을 제안한다. 또한 제안한 방법을 검증하기 위하여 MATLAB을 이용하여 모의실험을 수행하였다. 실험 결과로부터 제안한 방법은 CW, DSSS, SCW 형태의 교란신호를 정상적으로 식별하고 측정치를 정확하게 획득하는 것을 검증하였다.

• Archives of Plastic Surgery
• /
• 제40권4호
• /
• pp.312-319
• /
• 2013

Over the past decade, driven by advances in educational theory and pressures for efficiency in the clinical environment, there has been a shift in surgical education and training towards enhanced simulation training. Microsurgery is a technical skill with a steep competency learning curve on which the clinical outcome greatly depends. This paper investigates the evidence for educational and training interventions of traditional microsurgical skills courses in order to establish the best evidence practice in education and training and curriculum design. A systematic review of MEDLINE, EMBASE, and PubMed databases was performed to identify randomized control trials looking at educational and training interventions that objectively improved microsurgical skill acquisition, and these were critically appraised using the BestBETs group methodology. The databases search yielded 1,148, 1,460, and 2,277 citations respectively. These were then further limited to randomized controlled trials from which abstract reviews reduced the number to 5 relevant randomised controlled clinical trials. The best evidence supported a laboratory based low fidelity model microsurgical skills curriculum. There was strong evidence that technical skills acquired on low fidelity models transfers to improved performance on higher fidelity human cadaver models and that self directed practice leads to improved technical performance. Although there is significant paucity in the literature to support current microsurgical education and training practices, simulated training on low fidelity models in microsurgery is an effective intervention that leads to acquisition of transferable skills and improved technical performance. Further research to identify educational interventions associated with accelerated skill acquisition is required.

• 한국정보통신학회논문지
• /
• 제18권7호
• /
• pp.1713-1720
• /
• 2014

RFID 기술은 태그 아이디 정보 획득이라는 기본적인 역할을 넘어 태그 아이디와 위치 정보를 동시에 획득하는 기술이 개발되고 있으며 최근 들어서는 이동태그의 속도, 방향 등 부가적인 정보도 획득하는 방향으로 발전하고 있다. 본 논문에서는 서로 다른 속도로 이동하는 다수의 태그 부착 물체들에 대한 태그 아이디 획득 및 거리, 속도 등 부가적인 정보를 추출할 수 있는 RFID 시스템을 제안한다. 제안된 시스템에서는 태그는 FMCW로 변조된 아이디 신호를 전송하며 리더는 배열(array) 안테나를 이용해서 방위각 방향으로 태그 신호를 일차 분리하고 이어서 FMCW 복조를 통해서 속도, 거리 외에 태그 아이디를 복조한다. 요구된 기능을 수행하기 위한 리더 수신부 구조를 제시하고 제시된 시스템이 동작 가능함을 이론적으로 분석하며 시뮬레이션을 통해서 제시된 시스템의 성능을 검증한다.

• 산업공학
• /
• 제23권3호
• /
• pp.221-228
• /
• 2010

With the development of science and technology, modern submarines are equipped with high technology devices and multi-functioned precise armaments, consequently, acquisition cost as well as maintenance cost of the submarines are getting higher and higher. However, tight defense budget forces navy to significantly reduce military operating and maintenance costs. In this study, the maintenance and operating costs of submarine Jangbogo-II are estimated through M&S (Modeling and simulation) methodologies in order to reasonably and consistently work out the requirement verification system of Jangbogo-II. The maintenance and operating costs of Jangbogo-II along the next 25 years are estimated as 312.65 billion won via engineering analysis methods while 312.69 billion won from PRICE Model, which shows only 0.04 billion won differences as a whole. This study is expected to be able to provide meaningful decision making data for not only short and/or mid term operating planning but military budgeting.

• 융합신호처리학회 학술대회논문집
• /
• 한국신호처리시스템학회 2005년도 추계학술대회 논문집
• /
• pp.209-212
• /
• 2005

This paper describes detection and tracking of a moving object for unmanned visual surveillance. security systems. Using images obtained from camera it detects and tracks a moving object and displays bounding box enclosing the moving object. The algorithm for detection and tracking is tested using a personal computer, and then implemented on EMPOS II embedded system. Simulation results show that the tracking of a moving object based on embedded system is working well. However it needs to improve image acquisition time for real time implementation to apply security systems.

• 한국항해항만학회지
• /
• 제27권6호
• /
• pp.645-652
• /
• 2003

A virtual vessel traffic control system is introduced to contribute to prevent a marine accident such as collision and stranding from happening. Existing VTS has its limit. The virtual vessel traffic control system consists of both data acquisition by satellite remote sensing and a simulation of traffic environment stress based on the satellite data, remotely sensed data And it could be used to provide timely and detailed information about the marine safety, including the location, speed and direction of ships, and help us operate vessels safely and efficiently. If environmental stress values are simulated for the ship information derived from satellite data, proper actions can be taken to prevent accidents. Since optical sensor has a high spatial resolution, JERS satellite data are used to track ships and extract their information. We present an algorithm of automatic identification of ship size and velocity. It lastly is shown that based on ship information extracted from JERS data, a qualitative evaluation method of environmental stress is introduced.

• 대한전기학회논문지:시스템및제어부문D
• /
• 제53권11호
• /
• pp.786-792
• /
• 2004

A wavelet based ECG data compression has become an attractive and efficient method in many mobile tele-cardiology applications. But large data size required for high compression performance leads a serious delay. In this paper, new wavelet compression method with minimum delay is proposed. It is based on deciding the type and compression ratio(CR) of block organically according to the standard deviation of input ECG data with minimum block size. Compression performances of the proposed algorithm for different MIT ECG Records were analyzed comparing other ECG compression algorithm. In addition to the processing delay measurement, compression efficiency and reconstruction sensitivity to error were also evaluated via random noise simulation models. The results show that the proposed algorithm has both lower PRD than other algorithm on same CR and minimum time in the data acquisition, processing and transmission.

• 한국태양에너지학회 논문집
• /
• 제29권5호
• /
• pp.1-7
• /
• 2009

Energy demands for offices in Korea are surveyed and analyzed to generate communicational models for simulations. Daily energy loads of 13 office buildings scattered in the 6 largest cities in the country are surveyed and analyzed based on energy consumption log sheets. Detailed hourly loads that are frequently required when a detailed operation simulation is performed are measured using remote data acquisition processes for 3 offices. The complete load demand models of electricity, cooling, heating and hot water are established by combining the daily and hourly patterns based on the statistical behavior of the hourly patterns.

• ETRI Journal
• /
• 제29권5호
• /
• pp.596-606
• /
• 2007

It is well known that an OFDM receiver is vulnerable to synchronization errors. Despite fine estimations used in the initial acquisition, there are still residual synchronization errors. Though these errors are very small, they severely degrade the bit error rate (BER) performance. In this paper, we propose a residual error elimination scheme for the digital OFDM baseband receiver aiming to improve the overall BER performance. Three improvements on existing schemes are made: a pilot-aided recursive algorithm for joint estimation of the residual carrier frequency and sampling time offsets; a delay-based timing error correction technique, which smoothly adjusts the incoming data stream without resampling disturbance; and a decision-directed channel gain update algorithm based on recursive least-squares criterion, which offers faster convergence and smaller error than the least-mean-squares algorithms. Simulation results show that the proposed scheme works well in the multipath channel, and its performance is close to that of an OFDM system with perfect synchronization parameters.

• Investigative Magnetic Resonance Imaging
• /
• 제12권2호
• /
• pp.123-130
• /
• 2008

목적 : 본 논문에서는 자기공명영상 데이터 획득 시 객체의 움직임이 병렬 자기공명영상에 미치는 영향에 대하여 연구하였다. 일반적으로 병렬 자기공명영상 방법의 경우 데이터 획득 시간이 일반 자기공명영상 방법보다 짧기 때문에 움직임에 강인하다고 알려져 있다. 그러나 생체내의 비자발적인 장기 운동 등과 같은 불가피한 움직임이 포함된 경우 병렬 영상의 움직임 아티펙트는 일반적인 영상에 비하여 더 심각할 수 있다. 따라서 본 논문에서는 실제 환경에서 나타날 수 있는 다양한 움직임 종류를 정의하고, 이러한 움직임이 발생하였을 때 병렬 자기공명영상에 나타나는 영향을 일반적인 영상방법과 비교하여 살펴보았다. 대상 및 방법 : 병렬 자기공명영상 데이터를 획득할 때 발생하는 움직임에 의한 영향을 확인하기 위하여 실제 환경에서 발생할 수 있는 5가지 움직임 종류를 정의하였다. 즉 움직임-1과 2는 서로 다른 크기와 주기를 갖는 주기적인 움직임이고, 움직임-3과 4는 일정 시간 (segment) 단위로 운동하는 선형적인 움직임이다. 마지막으로 움직임-5는 비 주기 랜덤 운동이다. 사용된 영상 방법은 직각 좌표 기반 영상과 나선 주사 (비 직각 좌표) 영상으로 각각에 대해 병렬 영상법과 일반적인 영상법을 적용하여 움직임 효과를 살펴 보았다. 결과 : 본 논문에서 정의한 움직임 종류에 대한 병렬 자기공명영상에서의 움직임 효과를 알아보았다. 움직임-3과 4와 같이 병렬 자기공명영상에 의하여 움직임이 감소하는 경우 움직임 아티팩트는 일반 자기공명영상에 비하여 줄어들었다. 그러나 움직임-1과 2와 같이 주기적으로 진동할 경우 병렬 영상의 왜곡이 일반 자기공명영상에 비하여 더 크게 나타났다. 움직임-5와 같이 랜덤 한 경우 일반 자기공명영상과 병렬 자기공명영상이 서로 유사하게 나타났다. 결론 : 본 논문에서는 자기공명영상 데이터 획득 시 객체의 움직임이 병렬 자기공명영상에 미치는 영향에 대하여 연구하였다. 그 결과 병렬 자기공명영상을 통해 움직임이 줄어드는 경우를 제외한 다른 움직임 종류에 대해서는 병렬 자기공명영상보다 일반 자기공명영상이 더 좋은 화질을 나타내었다.