• Journal of electromagnetic engineering and science
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• 제19권2호
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• pp.107-114
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• 2019

Alert-confirm detection is a highly efficient method to improve phased array radar search performance. It comprises sequential detection in two steps: alert detection, in which a target is detected at a low detection threshold, and confirm detection, which is triggered by alert detection with a longer dwell time to minimize false alarms. This paper provides a design method for applying the alert-confirm detection to multifunctional radars. We find optimum dwell times and false alarm probabilities for each alert detection and confirm detection under the dual constraints of total false alarm probability and maximum allowable dwell time per position. These optimum values are expressed as a function of the mean new target appearance rate. The proposed alert-confirm detection increases the maximum detection range even with a shorter frame time than that of uniform scanning.

• Agricultural and Biosystems Engineering
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• 제2권2호
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• pp.69-74
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• 2001

Detection of operation lines in farm works, object recognition and obstacle avoidance are essential pre-requisite technologies for unmanned agricultural machinery. A CCD camera, which has been largely used for these functions, is expensive and has difficulty in real-time signal processing. In this study, a laser range sensor was selected as the guiding vision for unmanned agricultural machinery such as a tractor. To achieve this capability, algorithms for distance measurement, signal filtering, object recognition, and obstacle avoidance were developed. Computer simulations were carried out to evaluate performance of the algorithms. Experiments were also conducted with various materials and shapes, Laser beam lost its intensity for poor reflective materials, resulting in less range value than actual, so a compensation technique was considered to be necessary. Object detection system was fabricated on an agricultural tractor and the performance was evaluated. As test result for obstacle detection and avoidance in field, to detect and avoid obstacle for path finding with guiding system for unmanned agricultural machinery was enable.

• 대한임상검사과학회지
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• 제36권2호
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• pp.98-109
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• 2004

The lower limit of detection, precision, setting method of target value, reportable range determination, recovery, linearity, and comparison study with another equipment was evaluated for the Toshiba-120FR chemistry autoanalyzer which was newly introduced at the Daejeon Veteran Hospital in Dec. 2003. Nineteen kinds of test for AST, ALT, ALP, LDH, GGT, TP, ALB, GLU, T-cho, T-bil, TG, UA, CAL, IP, AMY, HDL-C, LDL-C, Cre and BUN were performed to evaluate the lower limit of detection, precision, setting method of target value, reportable range determination, recovery, linearity, and comparison study with other equipment according to the NCCLS guidelines(EP5-A, EP6-P, EP9-A). The Toshiba-120FR autochemical analyzer showed good precision for all tested items. The data concerning the lower limit of detection, precision(total CV 0.47%~3.65%), setting method of target value, reportable range determination, recovery(93%~111%), linearity($R^2=0.997{\sim}0.999$), and comparison study(r=0.977~0.999) with other equipment was acceptable for all tested items. The results of evaluation for the Toshiba-120FR autochemical analyzer showed that this equipment could be used as an alternative to other equipment.

• 한국통신학회논문지
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• 제35권12B호
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• pp.1244-1250
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• 2010

본 논문에서는 고속으로 이동하는 표적을 탐지 및 레인징하기 위해서 높은 PRF(Pulse repetition frequency)로 동작하는 레이더의 신호처리 알고리즘을 제시한다. 제시된 방법은 준주기성(quasi-periodic) 펄스열을 사용하므로써 이동표적의 도플러 정보를 추정하고 이를 보상해서 코히어런트하게 레인지 프로세싱 하는 것으로 기존 방식과는 달리 도플러 프로세싱이 레인지 프로세싱에 선행되며 이를 통해서 SNR이 낮은 잡음 환경에서도 표적 탐지 및 레인징이 가능함을 보인다. 제시된 알고리즘을 수학적으로 유도하고 디지털 신호처리를 위한 도플러/레인징 샘플링 조건, 프로세싱 시간 및 도플러 오차가 성능에 미치는 영향에 대해 기술하고 시뮬레이션을 통해서 이를 검증한다.

• 한국전자파학회지:전자파기술
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• 제11권4호
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• pp.39-52
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• 2000

A design of 2 stage S-DLVA(successive detector log video amplifier) was studied to detect wide dynamic radar pulse ranging from -70 ㏈m to 0㏈m. A basic design idea was focused on the linear detection in logarithmic scale of wide dynamic range radar pulses from nosie-like weak power of -70 ㏈m to relatively high power 0 ㏈m. It is highly formidable, since it requires high speed detection less than 10 nsec over the operating frequency ranges from 6 to 18 ㎓. A limiter diode, a tunnel diode and an L17-C were used as a protecting device, a detector diode and a log video amplifier in companion as a single stage detector to give voltage output proportional to the input power of about 35 ㏈ dynamic range. A protype of 2-stage DLVA having one more single stage detector was fabricated with a 32 ㏈ low noise amplifier and a 3 ㏈ hybrid coupler to provide total 70 ㏈ dynamic range detection. The logging characteristics were measured to have log slope of 25m.V/㏈ against 70 ㏈ logging range from -55 ㏈m to +15 ㏈m, the log linearity of within +/- 1.5 ㏈, and tangential sensitivity was at -63 ㏈m. The pulse dynamics of rise time and recovery time were measured as 50 nsec and 1.2 $\mu$sec, respectively. The reason might be due to the parasitic capacitances of packaged limiter, tunnel diode, and L17-C.

• ETRI Journal
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• 제42권1호
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• pp.46-53
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• 2020

Gait analysis is an effective clinical tool across a wide range of applications. Recently, inertial measurement units have been extensively utilized for gait analysis. Effective gait analyses require good estimates of heel-strike and toe-off events. Previous studies have focused on the effective device position and type of triaxis direction to detect gait events. This study proposes an effective heel-strike and toe-off detection algorithm using a smart insole with inertial measurement units. This method detects heel-strike and toe-off events through a time-frequency analysis by limiting the range. To assess its performance, gait data for seven healthy male subjects during walking and running were acquired. The proposed heel-strike and toe-off detection algorithm yielded the largest error of 0.03 seconds for running toe-off events, and an average of 0-0.01 seconds for other gait tests. Novel gait analyses could be conducted without suffering from space limitations because gait parameters such as the cadence, stance phase time, swing phase time, single-support time, and double-support time can all be estimated using the proposed heel-strike and toe-off detection algorithm.

• 제어로봇시스템학회논문지
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• 제17권6호
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• pp.521-525
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• 2011

Lane marking detection is one of important issues in the field of autonomous mobile robot. Especially, in urban environment, like pavement roads of downtown or tour tracks of Science Park, which have continuous patterns on the surface of the road, the lane marking detection becomes more important ability. Although there were many researches about lane detection and lane tracing, many of them used vision sensors mainly to detect lane marking. In this paper, we obtain 2 dimensional library data of 'Intensity' and 'Distance' using one laser rangefinder only. We design a simple classifier and filtering algorithm for the lane detection which uses only one LRF (Laser Range Finder). Allowing extended usage of LRF, this research provides more functionality not only in range finding but also in lane detecting to mobile robots. This work will be technically helpful for robot developers to design more simple and efficient autonomous driving system using LRF.

• 한국정보통신학회논문지
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• 제13권10호
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• pp.2189-2196
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• 2009

광파이버 네트웍에서 광전믹싱 광검파의 가용 주파수대역 확장을 위한 이론을 제시하고 시뮬레이션을 실시하였다. 광전믹싱 광검파의 정규화 이득을 정의하고, 검파소자의 차단주파수를 초월하는 고주파 영역의 신호도 검파가 가능함을 확인하였다. 포토다이오드 내부의 캐리어 천이에 대한 연속방정식을 풀어서 광전믹싱 현상의 메카니즘을 해석하였다. 정규화 이득은 신호주파수와 차주파수의 크기에 의존하였으나, 포토다이오드에 흐르는 광전류의 크기는 신호주파수와는 무관하였다. 신호 검파효율의 최대화를 위해서는 바이어스 전압과 국부신호의 진폭을 동시에 최적화할 필요가 있다.

• 한국국방경영분석학회지
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• 제6권2호
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• pp.27-46
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• 1980

Computer model for calculating the maximum detection range of the pulse radar used for surface surveillance is developed, and the detailed procedures of each theoretical step are discussed. The quantity of radar antenna's receiving energy, transmitting energy and noise level are compared in this model. All the calculation steps are programmed in BASIC language. Finally, I have found the output of this model well matched with the some experimental results.

• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.539-543
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• 2005

The research presented in this paper enables real-time 3D modeling to help make construction processes ultimately faster, more predictable and safer. Initial research efforts used an emerging sensor technology and proved its usefulness in the acquisition of range information for the detection and efficient representation of static and moving objects. Based on the time-of-flight principle, the sensor acquires range and intensity information of each image pixel within the entire sensor's field-of-view in real-time with frequencies of up to 30 Hz. However, real-time working range data processing algorithms need to be developed to rapidly process range information into meaningful 3D computer models. This research ultimately focuses on the application of safer heavy equipment operation. The paper compares (a) a previous research effort in convex hull modeling using sparse range point clouds from a single laser beam range finder, to (b) high-frame rate update Flash LADAR (Laser Detection and Ranging) scanning for complete scene modeling. The presented research will demonstrate if the FlashLADAR technology can play an important role in real-time modeling of infrastructure assets in the near future.