• 한국군사과학기술학회지
• /
• 제15권3호
• /
• pp.272-287
• /
• 2012

The optimal use of sonar systems for detection is a practical problem in a given ocean environment. In order to quantify the mission achievability in general, measure of effectiveness(MOE) is defined for specific missions. In this paper, using the specific MOE for detection, which is represented as cumulative detection probability(CDP), an integrated software package named as Optimal Acoustic Search Path Planning(OASPP) is developed. For a given ocean environment and sonar systems, the discrete observations for detection probability(PD) are used to calculate CDP incorporating sonar and environmental parameters. Also, counter-detection probability is considered for vulnerability analysis for a given scenario. Through modeling and simulation for a simple case for which an intuitive solution is known, the developed code is verified.

• 전자공학회논문지A
• /
• 제29A권7호
• /
• pp.1-9
• /
• 1992

In this thesis, the trellis detection scheme is proposed to improve the error performance of the noncoherent detection in the TFM system. Trellis detection takes advantage of the trellis property of TFM-encoded signals. The trellis property is created by giving correlations among adjacent TFM-encoded signals at the transmitter. The performance of the trellis detection scheme is analyzed by means of the Bernoulli trials with the average symbol error probability, and is compared to that of the bit-by-bit detection scheme. As a result,when the SNR is below 20 dB in the Rayleigh fading and AWGN channel, the trellis detection is inferior to the bit-by-bit detections. But when SNR is above 20 dB, the trellis detection is superior to the bit-by-bit detection, and its performance enhancement is better as the SNR increases.

• 센서학회지
• /
• 제23권4호
• /
• pp.251-258
• /
• 2014

While the feasibility of vertical velocity as a threshold parameter for pre-impact fall detection has been verified, effects of sensor attachment locations and methods calculating vertical acceleration and velocity on the detection performance have not been studied yet. Regarding the vertical velocity-based pre-impact fall detection, this paper investigates detection accuracies of eight different cases depending on sensor locations (waist vs. sternum), vertical accelerations (accurate acceleration based on both accelerometer and gyroscope vs. approximated acceleration based on only accelerometer), and vertical velocities (velocity with attenuation vs. velocity difference). Test results show that the selection of waist-attached sensor, accurate acceleration, and velocity with attenuation based on accelerometer and gyroscope signals is the best in overall in terms of sensitivity and specificity of the detection as well as lead time.

• 한국군사과학기술학회지
• /
• 제15권5호
• /
• 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.

• 한국컴퓨터정보학회논문지
• /
• 제22권6호
• /
• pp.131-140
• /
• 2017

As video equipments such as CCTV are used for various purposes in fields of society, digital video data processing technology such as automatic motion detection is essential. In this paper, we proposed and implemented a more stable and accurate motion detection system based on background subtraction technique. We could improve the accuracy and stability of motion detection over existing methods by efficiently processing color information of digital image data. We divided the procedure of color information processing into each components of color information : brightness component, color component of color information and merge them. We can process each component's characteristics with maximum consideration. Our color information processing provides more efficient color information in motion detection than the existing methods. We improved the success rate of motion detection by our background update process that analyzed the characteristics of the moving background in the natural environment and reflected it to the background image.

• International Journal of Advanced Culture Technology
• /
• 제11권1호
• /
• pp.370-375
• /
• 2023

As we enter a super-aged society, studies are being conducted to reduce complications and deaths caused by falls in elderly adults. Research is being conducted on interventions for preventing falls in the elderly, wearable devices for detecting falls, and methods for improving the performance of fall detection algorithms. Wearable devices for detecting falls of the elderly generally use gyro sensors. In addition, to improve the performance of the fall detection algorithm, an artificial intelligence algorithm is applied to the x, y, z coordinate data collected from the gyro sensor. In this paper, we develop a wearable device that uses a gyro sensor, body temperature, and heart rate sensor for health management as well as fall detection for the elderly. In addition, we develop a fall detection and health management system that works with wearable devices and a guardian's mobile app to improve the performance of the fall detection algorithm and provide health information to guardians.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2022년도 춘계학술대회
• /
• pp.437-440
• /
• 2022

현대 사회는 4차 산업 혁명과 IoT 기술 등의 발전으로 영상 처리 분야의 활용이 급증하고 있다. 특히, 에지 검출은 이미지 분류, 객체 검출 등 영상 처리 응용에서 필수적인 전처리 과정으로 여러 분야에서 널리 사용되고 있다. 에지를 검출하기 위한 기존의 방법에는 소벨 필터(Sobel edge detection filter), 로버츠 필터(Roberts edge detection filter), 프리윗 필터(Prewitt edge detection filter), LoG(Laplacian of Gaussian) 등이 있다. 하지만 기존의 방법들은 명암도가 낮은 저조도 환경에서 에지 검출 특성이 다소 미흡한 성능을 보인다는 단점이 있다. 따라서 본 논문에서는 저조도 환경에서도 에지 검출 특성을 높이기 위해 명암도 분석에 기반한 에지 검출 알고리즘을 제안한다.

• 대한원격탐사학회지
• /
• 제39권1호
• /
• pp.77-86
• /
• 2023

Ship detection is widely used in areas such as maritime security, maritime traffic, fisheries management, illegal fishing, and border control, and ship detection is important for rapid response and damage minimization as ship accident rates increase due to recent increases in international maritime traffic. Currently, according to a number of global and national regulations, ships must be equipped with automatic identification system (AIS), which provide information such as the location and speed of the ship periodically at regular intervals. However, most small vessels (less than 300 tons) are not obligated to install the transponder and may not be transmitted intentionally or accidentally. There is even a case of misuse of the ship'slocation information. Therefore, in this study, ship detection was performed using high-resolution optical satellite images that can periodically remotely detect a wide range and detectsmallships. However, optical images can cause false-alarm due to noise on the surface of the sea, such as waves, or factors indicating ship-like brightness, such as clouds and wakes. So, it is important to remove these factors to improve the accuracy of ship detection. In this study, false alarm wasreduced, and the accuracy ofship detection wasimproved by removing wake.As a ship detection method, ship detection was performed using machine learning-based random forest (RF), and convolutional neural network (CNN) techniquesthat have been widely used in object detection fieldsrecently, and ship detection results by the model were compared and analyzed. In addition, in this study, the results of RF and CNN were combined to improve the phenomenon of ship disconnection and the phenomenon of small detection. The ship detection results of thisstudy are significant in that they improved the limitations of each model while maintaining accuracy. In addition, if satellite images with improved spatial resolution are utilized in the future, it is expected that ship and wake simultaneous detection with higher accuracy will be performed.

• 전기전자학회논문지
• /
• 제26권4호
• /
• pp.622-627
• /
• 2022

본 논문에서는 공격 횟수와 공격 유형을 모두 고려하여 차량 내 네트워크에서 해킹을 탐지하는 침입 탐지 시스템의 성능을 개선하는 기법을 제안한다. 침입 탐지 시스템에서 침입을 정상으로 잘못 인식하는 FNR(False Negative Rate)과 정상을 침입으로 잘못 인식하는 FPR(False Positive Rate)은 모두 차량의 안전에 큰 영향을 미친다. 본 논문에서는 일정 홧수 이상 공격으로 탐지된 데이터 프레임을 자동적으로 공격으로 처리하며, 자동 공격으로 판단하는 방법도 공격 유형에 따라 다르게 적용함으로서 FNR과 FPR을 모두 개선하는 침입 탐지 기법을 제안하였다. 시뮬레이션 결과 제안하는 기법은 DoS(Denial of Service) 공격과 Spoofing 공격에서 FNR과 FPR을 효과적으로 개선할 수 있었다.

• 대한임베디드공학회논문지
• /
• 제9권5호
• /
• pp.261-268
• /
• 2014

Face detection is essential to the full automation of face image processing application system such as face recognition, facial expression recognition, age estimation and gender identification. It is found that local image features which includes Haar-like, LBP, and MCT and the Adaboost algorithm for classifier combination are very effective for real time face detection. In this paper, we present a face detection method using local pixel direction code(PDC) feature and lookup table classifiers. The proposed PDC feature is much more effective to dectect the faces than the existing local binary structural features such as MCT and LBP. We found that our method's classification rate as well as detection rate under equal false positive rate are higher than conventional one.