• Title/Summary/Keyword: processing velocity

Search Result 876, Processing Time 0.03 seconds

Side Looking Vehicle Detection Radar Using A Novel Signal Processing Algorithm (새로운 신호처리 알고리즘을 이용한 측방설치 차량감지용 레이다)

  • Kang Sung Min;Kim Tae Young;Choi Jae Hong;Koo Kyung Heon
    • Journal of the Institute of Electronics Engineers of Korea TC
    • /
    • v.41 no.12
    • /
    • pp.1-7
    • /
    • 2004
  • We have developed a 24GHz side-looking vehicle detection radar. A 24GHz front-end module and a novel signal processing algorithm have been developed for speed measurement and size classification of vehicles in multiple lanes. The system has a fixed antenna and FMCW processing module. This paper presents the background theory of operation and shows some measured data using the algorithm. The data shows that measured velocity of the passing vehicle is within the accuracy of 95% in single lane and the velocity of the vehicles in two lanes is within the accuracy of 90% by using variable threshold estimation. The classification of vehicle size as small, medium and large has been measured with 89% accuracy.

Study on MMTI Signal Processing Algorithm and Analysis of the Performance for Periscope Detection in Airborne Radar (항공용 레이다를 이용한 잠망경 탐지 MMTI 신호처리 기법 연구 및 성능 분석)

  • Jung, Jae-Hoon;Lee, Jae-Min;Youn, Jae-Hyuk;Shin, Hee-Sub
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.28 no.8
    • /
    • pp.661-669
    • /
    • 2017
  • This paper describes an MMTI(Maritime Moving Target Indicator) for periscope detection in airborne radar. Firstly, we analyze the characteristics of sea clutter, sea targets. Secondly, we study the differences between GMTI(Ground Moving Target Indicator) and MMTI. This paper proposes an optimal MMTI operating environment and method. We also suggest a signal processing algorithm using STAP(Space-Time Adaptive Processing) for detecting small RCS target moving low speed. The detection probability for moving target with MDV(Minimum Detectable Velocity) is simulated under various RCS and multi-channel system. Finally, we analyze the major performance for range, velocity and azimuth accuracy.

Development of Amorphous Iron Based Coating Layer using High-velocity Oxygen Fuel (HVOF) Spraying (철계 비정질 분말을 활용한 초고속 용사 코팅층 개발)

  • Kim, Jungjoon;Kim, Song-Yi;Lee, Jong-Jae;Lee, Seok-Jae;Lim, Hyunkyu;Lee, Min-Ha;Kim, Hwi-Jun;Choi, Hyunjoo
    • Journal of Powder Materials
    • /
    • v.28 no.6
    • /
    • pp.483-490
    • /
    • 2021
  • A new Fe-Cr-Mo-B-C amorphous alloy is designed, which offers high mechanical strength, corrosion resistance as well as high glass-forming ability and its gas-atomized amorphous powder is deposited on an ASTM A213-T91 steel substrate using the high-velocity oxygen fuel (HVOF) process. The hybrid coating layer, consisting of nanocrystalline and amorphous phases, exhibits strong bonding features with the substrate, without revealing significant pore formation. By the coating process, it is possible to obtain a dense structure in which pores are hardly observed not only inside the coating layer but also at the interface between the coating layer and the substrate. The coating layer exhibits good adhesive strength as well as good wear resistance, making it suitable for coating layers for biomass applications.

Improvement of the Mechanical Property and Corrosion Resistivity of the Ni-/Fe-based Hybrid Coating Layer using High-velocity Oxygen Fuel Spraying by Heat Treatment (열처리를 통한 Ni/Fe계 하이브리드 용사 코팅층의 기계적 특성 및 내식성 향상)

  • Kim, Jungjoon;Lee, Yeonjoo;Kim, Song-Yi;Lee, Jong-Jae;Kim, Jae-hun;Lee, Seok-Jae;Lim, Hyunkyu;Lee, Min-Ha;Kim, Hwi-Jun;Choi, Hyunjoo
    • Journal of Powder Materials
    • /
    • v.29 no.3
    • /
    • pp.240-246
    • /
    • 2022
  • Novel Ni- and Fe-based alloys are developed to impart improved mechanical properties and corrosion resistance. The designed alloys are manufactured as a powder and deposited on a steel substrate using a high-velocity oxygen-fuel process. The coating layer demonstrates good corrosion resistance, and the thus-formed passive film is beneficial because of the Cr contained in the alloy system. Furthermore, during low-temperature heat treatment, factors that deteriorate the properties and which may arise during high-temperature heat treatment, are avoided. For the heattreated coating layers, the hardness increases by up to 32% and the corrosion resistance improves. The influence of the heat treatment is investigated through various methods and is considered to enhance the mechanical properties and corrosion resistance of the coating layer.

Laboratory Determination of Compressional wave Velocity for Unconsolidated Marine Sediment (미고결 해저퇴적물의 음파전달속도 측정에 관한 연구)

  • KIM Dae-Choul
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.22 no.3
    • /
    • pp.147-153
    • /
    • 1989
  • Laboratory measurement of compressional wave velocity for two piston cores has been carried out successfully. The cores penetrated into the Holocene mud deposit located just off the Pusan harbor. Differences between the mercury delay method using a mercury column and the time delay method utilizing a digital processing oscilloscope for the observed velocity are negligible. Thus, both methods can be used independently to determine the velocity of unconsolidated marine sediment. The core velocity is, however, always higher than the velocity calculated from the seismic profile. This result should be considered seriously to interprete a seismic profile, otherwise one may encounter systematic error in calculating sediment thickness.

  • PDF

An implementation of the continuous wave doppler system for blood flow measurement using the ultrasound (효율적인 혈류 속도 측정을 위한 연속 초음파 도플러 장치의 구현)

  • 박형재;김영길
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
    • /
    • 2001.05a
    • /
    • pp.516-519
    • /
    • 2001
  • To diagnose a patient's blood vessel disease, apoplexy, hypertension, arteriosclerosis, the blood velocity is very important. Determining the blood velocity methods using ultrasound are Continuous Doppler System and Pulse Doppler System. In using the Pulse Doppler System, we can obtain the position of blood velocity. But it is more complex hardware than Continuous Doppler System and it has low SNR(signal-noise ratio). So in this study, to obtain a believable information we use the Continuous Pulse Doppler System. Thus system have analog part and digital part. In analog part is composed of ultrasound generating part, the amplifying part to amplify the received signal from ultrasound sensor, the demodulation part to detect blood velocity and the filtering part to remove the noise. In digital part is composed of the A/D conversion part, digital signal processing part, and the communication part to communicate the PC. In this study to implement efficient ultrasound blood velocity measurement system, we can get the patient's blood velocity information in realtime. Thus, It is a useful in the accurate diagnosis with C.T(computered tomography), M.R.I(magnetic resonance imaging).

  • PDF

A study on flow characteristics of laminar oscillatory flows in a square-sectional $180^{\circ}C$ curved duct (정사각단면 $180^{\circ}C$ 곡덕트에서 층류진동유동의 유동 특성에 관한 연구)

  • Park, Gil-Mun;Jo, Byeong-Gi;Bong, Tae-Geun
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.22 no.2
    • /
    • pp.139-152
    • /
    • 1998
  • In the present study, the flow characteristics of developing laminar oscillatory flows in a square -sectional 180 deg. curved duct are investigated experimentally. The experimental study using air in a square-sectional 180 deg. curved duct is carried out to measure velocity distributions with a data acquisition and LDV (Laser Doppler Velocimetry) processing system. In this system, Rotating Machinery Resolver (RMR) and PHASE program are used to obtain the results of unsteady flows. The major flow characteristics of developing oscillatory flows are found by analyzing velocity curves, mean velocity profiles, time-averaged velocity distribution of secondary flow, wall shear stress distributions, and entrance lengths. In a lower dimensionless angular frequency, the axial velocity distribution of laminar oscillatory flow in a curved duct shows a convex shape in a central part and axial symmetry. The maximum value of wall shear stress in a lower dimensionless angular frequency is located in an outside wall, but according to increasing the dimensionless angular frequency, the maximum of wall shear stress is moved to inner wall. The entrance lengths of laminar oscillatory flows in a square-sectional 180 deg. curved duct is obtained to 90 deg. of bended angle of duct in this experimental conditions.

Query Processing of Uncertainty Position Using Road Networks for Moving Object Databases (이동체 데이타베이스에서 도로 네트워크를 이용한 불확실 위치데이타의 질의처리)

  • Ahn Sung-Woo;An Kyung-Hwan;Bae Tae-Wook;Hong Bong-Hee
    • Journal of KIISE:Databases
    • /
    • v.33 no.3
    • /
    • pp.283-298
    • /
    • 2006
  • The TPR-tree is the time-parameterized indexing scheme that supports the querying of the current and projected future positions of such moving objects by representing the locations of the objects with their coordinates and velocity vectors. If this index is, however, used in environments that directions and velocities of moving objects, such as vehicles, are very often changed, it increases the communication cost between the server and moving objects because moving objects report their position to the server frequently when the direction and the velocity exceed a threshold value. To preserve the communication cost regularly, there can be used a manner that moving objects report their position to the server periodically. However, the periodical position report also has a problem that lineal time functions of the TPR-tree do not guarantee the accuracy of the object's positions if moving objects change their direction and velocity between position reports. To solve this problem, we propose the query processing scheme and the data structure using road networks for predicting uncertainty positions of moving objects, which is reported to the server periodically. To reduce an uncertainty of the query region, the proposed scheme restricts moving directions of the object to directions of road network's segments. To remove an uncertainty of changing the velocity of objects, it puts a maximum speed of road network segments. Experimental results show that the proposed scheme improves the accuracy for predicting positions of moving objects than other schemes based on the TPR-tree.

A Surface Image Velocimetry Algorithm for Analyzing Swaying Images (흔들리는 영상 분석을 위한 표면 영상 유속계 알고리듬)

  • Yu, Kwonk-Yu;Yoon, Byung-Man;Jung, Beom-Seok
    • Journal of Korea Water Resources Association
    • /
    • v.41 no.8
    • /
    • pp.855-862
    • /
    • 2008
  • Surface Image Velocimetry (SIV) is an instrument to measure water surface velocity by using image processing techniques. To improve its measuring accuracy, it is essential to get high quality images with low skewness. A truck-mounted SIV system would be a good way to get images, since its crane gives high altitude to the images. However, the images taken with a truck-mounted SIV would be swayed due to the movement of crane and the camera by winds. In that case, to analyze the images, it is necessary to compensate the side sway in the images. The present study is to develop an algorithm to analyze the swayed images by combining common image processing techniques and coordinate transform techniques. The system follows the traces of some selected fixed points and calculates the displacements of the video camera. By subtracting the average velocity of the fixed points from that of grid points, the velocity fields of the flow can be corrected. To evaluate the system's performance, two image sets were used, one image set without side sway and another set with side sway. The comparison of their results showed very close with the error of around 6 %.