• The Journal of the Acoustical Society of Korea
• /
• v.22 no.3
• /
• pp.224-232
• /
• 2003

In this paper, efficient deployment method of sensors and target positioning performance with respect to measurement error are dealt with. Active sonar can be categorized into Monostatic, Bistatic, Multistatic sonar, and characteristics of respective sonar are different. Assuming that each sensor can receive range and angular information, we compare the performance of Monostatic, Bistatic, and Multistatic systems. And we suggest Weighted least square (WLS) which gives the weight to former case, LS. In particular. adopting suggested method we investigate the target positioning performance according to number of sensor, distance from transmitter to receiver, and propose efficient arrangement rule for Multistatic sonar configurations. According to the experimental results, RMSE of Multistatic sonar is found to be superior to Monostatic and Bistatic by 35.98%. 37.45% respectively, and WLS is superior to LS approximately by 7.4% in average. Furthermore, as the difference of respective sensor's variance is large, it is observed that the improvement ratio of target positioning performance is increased.

• The Journal of the Acoustical Society of Korea
• /
• v.26 no.4
• /
• pp.166-172
• /
• 2007

In this paper, we address the target positioning performance of Multi-Static sonar with respect to target positioning method and measurement error. Based on the analysis on two candidate solution approaches, namely, Least Square (LS) using range and angular information simultaneously and Maximum Likelihood (ML) using only range information as the existing information fusion methods for possible application to Multi-Static sonar, we propose to employ ML using range and angular information. Assuming that each sensor can receive range and angular information, we conduct representative comparison experiments over the existing and proposed methods under various measurement noise scenarios. We also investigate the target positioning performance according to number of sensors, distance between transmitter and receiver. According to the experimental results, RMSE of the proposed ML with distance and direction information is found to be more superior to ML using distance alone and to LS in case distance between transmitter and receiver is longer and number of receiver is smaller.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.10 no.3 s.49
• /
• pp.13-20
• /
• 2006

Substations in electric power transmission network systems (EPTS) operate using several transformers in parallel to increase the efficiency in terms of stability of energy supply. We present a seismic reliability assessment method of EPTS considering the parallel operation of transformers. Two methods for damage state model are compared in this paper: bi-state and multi-damage model. Simulation results showed that both models yielded similar network reliability indices and the reliability indices of the demand nodes using hi-state model exhibited higher damage probability. Particularly, the corresponding EENS (Expected Energy Not Supplied) index was significantly larger than that of the multi-damage state.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.9 no.1 s.24
• /
• pp.24-32
• /
• 2006

This paper is to analyze the effectiveness of multistatic sonar network based on detection performance. The multistatic sonar network is a distributed detection system that places a source and multi-receivers apart. So it needs a detection technique that relates to decision rule and optimization of sonar system to improve the detection performance. For this we propose a data fusion procedure using Bayesian decision and optimal sensor arrangement by optimizing a bistatic sonar. Also, to analyze the detection performance effectively, we propose the environmental model that simulates a propagation loss and target strength suitable for multistatic sonar networks in real surroundings. The effectiveness analysis on the multistatic sonar network confirms itself as a promising tool for effective allocation of detection resources in multistatic sonar system.

• Journal of Korea Society of Industrial Information Systems
• /
• v.27 no.5
• /
• pp.49-59
• /
• 2022

The SHAPE algorithm has the advantage of being able to shape the pulse spectrum as desired and design it not to distort other characteristics, so it was used in the active sonar pulse design. In this paper, we propose a pulse design using the SHAPE algorithm for a multi-static sonar system to reduce the cross-correlation between frequency-adjacent pulses and prevent the performance degradation of the pulses themselves. The boundary function of the SHAPE algorithm is set to be limited to the pulse bandwidth. As a result of applying the proposed design method to the sinusoidal frequency modulated pulse, the peak cross-correlation level (PCCL), which means the degree of cross-correlation, was reduced by 44.23 dB. Although the PCCL decreased by several tens of dB, no significant change in the ambiguity function was observed, and the integrated sidelobe level (ISL), which means the average value of the side lobe, increased by 11.64 dB.

• Journal of Ocean Engineering and Technology
• /
• v.28 no.5
• /
• pp.429-439
• /
• 2014

The target echoes contain information on the target such as the orientation, kinematics, and internal structure, as well as the external geometrical shape of the target. In addition, the pattern of the target echoes depends on the arrangement of the transmitters and receivers in space. Therefore, the study of the target echoes in a multi-static SONAR system can be useful for detecting and tracking submerged objects using an underwater surveillance system. For this purpose, an acoustic measuring system for multi-static target echoes was designed and tested in an acoustic water tank. Some preliminary data are presented and discussed.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.14 no.2
• /
• pp.140-148
• /
• 2021

In this paper, we intend to improve the availability by integrating Sonobuoy, the most essential detection system used in anti-submarine operations, with LTE communication of smart devices. Anti-submarine capability to respond to the threat of North Korean submarine forces is becoming increasingly important, and continuous research and development is required. This paper aims to enhance the ability of acoustic tactics by using a military-only LTE communication system installed on a ship, smart devices that can be linked to it, and a multi-static sonobuoy controlled by them. The proposed system can increase the visual effect by not only displaying coordinate values by receiving accurate coordinate information of each sonobuoy to a smart device, but also displaying a marker on a map.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.15 no.5
• /
• pp.630-634
• /
• 2012

It is very important to place receiver in multistatic sonar. Inefficient placement of the receiver reduce detection probability and to increase the probability of detection should be used more receivers. Therefore, detection of targets in searching area, detection performance of limited receiver depends on how to place. Through the optimized receiver placement, detection area between each sonar as much as possible avoid duplication, as optimization, the minimum receiver can be maintained detection performance. In this paper we prove mathematical verification of maximum signal excess value based on sonar placement and we calculate a signal excess value by using computer simulations and suggest optimal sonar placement.

• Proceedings of the Korean Information Science Society Conference
• /
• 1999.10b
• /
• pp.236-238
• /
• 1999

컴퓨팅 능력의 발달과 네트워크의 대용량화로 인해서 다중 참여자를 고려한 분산 가상 환경에 대한 연구가 활발하게 이루어지고 있다. 분산 가상 환경은 네트워크를 통해서 연결된 다중의 참여자를 고려해야 하기 때문에 참여자 그룹 관리가 필수적으로 요구된다. 기존의 분산 가상 환경에서의 참여자 그룹 관리는 참여자의 가입, 탈퇴 처리와 현재 상태의 제공 기능 등을 지원하고 있다. 그러나, 다양한 형태의 참여자 활동을 지원하기 위해서는 현재 상태의 정보 뿐만 아니라 다양한 그룹 활동의 지원과 각각의 참여자가 수행한 작업의 형태와 그룹에 대한 정책등에 대한 적절한 관리가 필요하다. 이러한 작업은 기존의 참여자 그룹 관리 방식에는 중앙 서버에 지나친 부담을 주기 때문에 이에 대한 해결하기 위한 고려도 필요하다. 이 논문에서는 모빌 에이전트를 기반한 분산 가상 환경을 위한 참여자 그룹 관리 시스템을 설계하였다. 설계한 시스템의 특징은 하나의 그룹내에 다수의 소그룹이 존재할 수 있게 함으로써 보다 다양한 그룹 활동을 지원하며, 그룹의 현재 상태 정보 뿐만 아니라 그룹에 참여하는 각각의 참여자들의 행위 정보와 이동 정보를 관리함으로써 참여자를 진단을 욕하는 응용에 사용될 수 있다. 또한, 모빌 에이전트 형태로 설계함으로써 중앙 서버에 대한 지나친 부담 문제를 해결하였다.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.49 no.9
• /
• pp.172-180
• /
• 2012

In multi-static sonar for detecting an underwater target, received signals contain the target echo, reverberation and clutter. Clutter and reverberation are main causes of increasing the false alarm rate. MRAL classifies received signals according to the spatial similarity, and it regards classified signal as reflected signals from a reflector. MRAL reduces the false alarm rate this way. However, the results of MRAL can have localization errors. In this paper, an MRAL post processing algorithm is proposed to reduce the localization errors with the least square (LS) method.