• 한국음향학회지
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• 제40권4호
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• pp.330-336
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• 2021

양상태 능동 소나에서 수중 표적의 산란 강도는 사용된 신호의 주파수, 표적과 음원사이의 각도를 의미하는 자세각, 표적과 수신기 사이의 각도를 나타내는 양상태각 등의 운용 변수에 따라 다르게 나타난다. 따라서 양상태 소나의 표적 탐지 및 식별 성능은 소나 운용 과정에서 표적, 음원, 그리고 수신기의 위치를 어떻게 변화시키느냐에 따라 그 성능이 달라질 수 있다. 본 연구에서는 양상태 소나 운용 시 자세각을 변화시키는 경우와 양상태각을 변화시키는 경우의 표적 식별 성능을 비교하여 어떤 변수를 변화시키는 것이 유리한지 평가하였다. 속이 비어있는 구와 실린더를 식별하는 시나리오를 가정하였으며, 유한요소법 기반의 음향 산란 시뮬레이션을 이용하여, 서포트 벡터 머신으로 두 표적을 분류하고 정확도를 비교하는 방법으로 성능을 비교하였다. 표적의 산란 신호만을 고려하기 위하여, 해저면 잔향의 효과는 고려하지 않았다. 비교 결과, 자세각을 고정한 상태에서 주파수와 양상태각으로 정의되는 산란 강도를 이용하는 것이 우수한 평균 분류 정확도를 보여주었으며, 이는 양상태 소나를 이용하여 구와 실린더를 식별하고자 하는 경우, 음원의 위치를 고정시킨 상태에서 수신기를 이동하여 양상태각을 변화시키는 것이 표적 식별에 더 효과적임을 보여준다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.505-508
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• 2000

The success of target reconstruction in SAR(Synthetic Aperture Radar) imaging system is greatly dependent on the coherent detection. Primary causes of incoherent detection are uncompensated target or sensor motion, random turbulence in propagation media, wrong path in radar platform, and etc. And these appear as multiplicative phase error to the echoed signal, which consequently, causes fatal degradations such as fading or dislocation of target image. In this paper, we present iterative phase error estimation scheme which uses echoed data in all temporal frequencies. We started with analyzing wave equation for one point target and extend to overall echoed data from the target scene - The two wave equations governing the SAR signal at two temporal frequencies of the radar signal are combined to derive a method to reconstruct the complex phase error function. Eventually, this operation attains phase error correction algorithm from the total received SAR signal. We verify the success of the proposed algorithm by applying it to the simulated spotlight-mode SAR data.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1699-1704
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• 2005

In this research the energy degrader, which is the most fragile part of the security of a target, has been newly designed to improve the performance of the gas target. Also, the numerical analysis of the heat movement and mechanical movement during the operation of the target has been accomplished. The heat analysis and structure analysis which are using the cooling water flow and pressure in the energy degrader and the Nastran mediocrity finite element analysis program, has been considered with the heat movement and mechanical movement according to the current capacity of proton beam which determines the production yield of the radioactive isotope. Also the possible use range has been determined, and at the same time the most suitable running condition according to the current capacity of proton beam has been suggested.

• 대한의용생체공학회:의공학회지
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• 제24권1호
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• pp.45-53
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• 2003

Based on the 4-compartmental pharmacokinetic model developed in PART1, target-controlled infusion(TCI) pump system was designed and evaluated. The TCI system consists of digital board including microcontroller and digital signal process(DSP), analog board, motor-driven actuator, user friendly interface, power management and controller. It provides two modes according to the drugs: plasma target concentration and effect target concentration. Anaesthetist controls the depth of anaesthesia for patients by adjusting the required concentration to maintain both plasma and effect site in drug concentration. The data estimated in DSP include infusion rate, initial load dose, and rotation number of motor encoder. During TCI operation, plasma concentration. effect site concentration, awaken concentration, context-sensitive decrement time and system error information are displayed in real time. Li-ion battery guarantees above 2 hours without power line failure. For high reliability of the system, two microprocessors were used to perform independent functions for both pharmacokinetic algorithm and motor control strategy.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.54-56
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• 2006

To get the robust and reliable input command, we designed shaping function for target tracking system with commander's handle. Input signals of the commander's handle are generated by human operator. It is response of the human to reduce the error between target and gun. But, tracking error while operator aim a moving target manually gives poor system performance. Input noise, particularly, affects hit accuracy as the system performance. We proposed the design method of input command shaping to reduce the Input noise and to improve the operation ability and convenience. We performed the experiments with combat vehicle, example of Target Tracking System, to show the proposed method is efficient and practical.

• 한국공작기계학회논문집
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• 제15권3호
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• pp.24-31
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• 2006

The energy degrader is the most fragile part of the security of a target, has been newly designed to improve the performance of the gas target. Also, the numerical analysis of the heat movement and mechanical movement during the operation of the target has been accomplished. The heat analysis and structure analysis which are using the cooling water flow and pressure in the energy degrader and the finite element analysis program, has been considered with the heat movement and mechanical movement according to the current capacity of proton beam which determines the production yield of the radioactive isotope. Also the possible use range has been determined and at the same time the most suitable running condition according to the current capacity of proton beam has been suggested.

• 품질경영학회지
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• 제41권3호
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• pp.413-421
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• 2013

Purpose: System availability and life cycle cost are often used to evaluate the system performance and is influenced by the operation and maintenance characteristic. In this paper, we propose the method to improve life cycle cost and satisfy the target availability through redundancy allocation. Methods: We consider the redundancy is available at all items in multi level system. Thus, we assume that sub-assembly, module, components can be duplicated. Simulation and genetic algorithm are employed to optimize redundancy allocation. Results: Target availability is higher, the life cycle cost is increased. In addition, the items for redundancy are selected at higher level in multi level system if target availability is higher. Conclusion: We could know that target availability affects the duplication number of items and the selection of redundancy items. For further study, we will consider new optimization algorithms to compare with the proposed GA algorithm and improve optimization performance.

• 대한임베디드공학회논문지
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• 제13권6호
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• pp.321-328
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• 2018

This paper presents an automatic target tracking flight system using a PID controller based on velocity command of a multirotor UAV. The automatic flight system includes marker based onboard target detection and an automatic velocity command generation replacing manual controller. A quad-rotor UAV is equipped with a camera and an image processing computer to detect the marker in real time and to estimate the relative distance from the target. The marker tracking system consists of PID controller and generates velocity command based on the relative distance. The generated velocity command is used as the input of the UAV's original flight controller. The operation of the proposed system was verified through actual flight tests using a marker on top of a moving vehicle and tracks it to successfully demonstrate its capability using a quad-rotor UAV.

• 한국철도학회논문집
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• 제9권1호
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• pp.29-35
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• 2006

Trains in LRT(Light Railway Transit) system usually have shorter car length than metro's because of their smaller passensers demand. Therefore it is very likely that the load condition of LRT system in abnormal operation, in case of which trains are in close proximity by system broke or train rescue works, could be worse rather than in normal operation, in spite of rare probability of abnormal operation. In this study, the target reliability indexes of several abnormal operations are estimated in accordance with the occurrence probabilities of each abnormal operation case and the reliability index of normal operation presented by the specification. From the indexes, load factors for the abnormal operation cases are estimated and the safety evaluation is performed for Yong-in LRT project.

• 수산해양기술연구
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• 제57권4호
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• pp.334-341
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• 2021

The fishery compensation by marine spatial planning such as routeing of ships and offshore wind farms is required objective data on whether fishing vessels are engaged in a target area. There has still been no research that calculated the number of fishing operation days scientifically. This study proposes a novel method for calculating the number of fishing operation days using the fishing trajectory data when investigating fishery compensation in marine spatial planning areas. It was calculated by multiplying the average reporting interval of trajectory data, the number of collected data, the status weighting factor, and the weighting factor for fishery compensation according to the location of each fishing vessel. In particular, the number of fishing operation days for the compensation of driftnet fishery was considered the daily average number of large vessels from the port and the fishery loss hours for avoiding collisions with them. The target area for applying the proposed method is the routeing area of ships of Jeju outer port. The yearly average fishing operation days were calculated from three years of data from 2017 to 2019. As a result of the study, the yearly average fishing operation days for the compensation of each fishing village fraternity varied from 0.0 to 39.0 days. The proposed method can be used for fishery compensation as an objective indicator in various marine spatial planning areas.