• Title/Summary/Keyword: Synchronization Test

Search Result 165, Processing Time 0.03 seconds

A Performance Study of Tactical Data Link Transceiver in TDMA Networks (TDMA 네트워크 전술데이터링크 송수신기 구현 및 성능고찰)

  • Nam, Jeong-Ho;Seo, Nan-Sol;Jang, Dhong-Woon
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.13 no.3
    • /
    • pp.388-396
    • /
    • 2010
  • Generally, flight information is transmitted by voice signal over legacy UHF radio in ground to air communication system. In this paper, we have implemented the transceiver of TDL(tactical data link) which transmits tactical information, such as flight information, using digital signal. For transmitting digital information over radio path, we have designed data modem that is processing CPFSK modulation, and TDMA(Time Division Multiple Access) network for Synchronization among multi user(platform). By simulating aeronautical propagation modeling with the environment of Korea terrain, it is predicted the maximum performance of communication range of the transceiver. As result of the transceiver's aviational boarding test, it is proved that the transceiver of TDL over legacy UHF radio transmits and receives the tactical information in TDMA network within communication range of 160km.

Development and It's Real-sea Test of an Underwater Acoustic Communication System (수중무선통신 시스템 개발 및 성능시험)

  • Lim, Yong-Kon;Park, Jong-Won;Kim, Seung-Geun;Choi, Young-Chol;Kim, Sea-Moon;Byun, Sung-Hoon
    • Proceedings of the IEEK Conference
    • /
    • 2008.06a
    • /
    • pp.89-90
    • /
    • 2008
  • We present an implementation and it's real-sea test of an underwater acoustic communication system, which allows the system to reduce complexity and increase robustness in time variant underwater environments. For easy adaptation to complicated and time-varying environments of the ocean, all-digital transmitter and receiver systems were implemented. For frame synchronization the CAZAC sequence was used, and QPSK modulation/demodulation method with carrier frequency of 25kHz and a bandwidth of 5kHz were applied to generate 10kbps transmission rate including overhead. To improve transmission quality, we used several techniques and algorithms such as adaptive beamforming, adaptive equalizer, and convolution coding/Viterbi decoding. For the verification of the system performance, measurement of BER has been done in a very shallow water with depth of 20m at JangMok, Geoje. During the experiment, image data were successfully transmitted up to about 9.6km.

  • PDF

Development and Test of the Remote Operator Visual Support System Based on Virtual Environment (가상환경기반 원격작업자 시각지원시스템 개발 및 시험)

  • Song, T.G.;Park, B.S.;Choi, K.H.;Lee, S.H.
    • Korean Journal of Computational Design and Engineering
    • /
    • v.13 no.6
    • /
    • pp.429-439
    • /
    • 2008
  • With a remote operated manipulator system, the situation at a remote site can be rendered through remote visualized image to the operator. Then the operator can quickly realize situations and control the slave manipulator by operating a master input device based on the information of the virtual image. In this study, the remote operator visual support system (ROVSS) was developed for viewing support of a remote operator to perform the remote task effectively. A visual support model based on virtual environment was also inserted and used to fulfill the need of this study. The framework for the system was created by Windows API based on PC and the library of 3D graphic simulation tool such as ENVISION. To realize this system, an operation test environment for a limited operating site was constructed by using experimental robot operation. A 3D virtual environment was designed to provide accurate information about the rotation of robot manipulator, the location and distance of operation tool through the real time synchronization. In order to show the efficiency of the visual support, we conducted the experiments by four methods such as the direct view, the camera view, the virtual view and camera view plus virtual view. The experimental results show that the method of camera view plus virtual view has about 30% more efficiency than the method of camera view.

A full-color anaglyph three-dimensional display system using active color filter glasses

  • Kim, Jong-Hyun;Kim, Young-Hoon;Hong, Ji-Soo;Park, Gil-Bae;Hong, Kee-Hoon;Min, Sung-Wook;Lee, Byoung-Ho
    • Journal of Information Display
    • /
    • v.12 no.1
    • /
    • pp.37-41
    • /
    • 2011
  • Presented herein is a novel stereoscopic three-dimensional (3D) display system with active color filter glasses. This system provides full-color 3D images by applying the time-multiplexing technique on the original anaglyph method. By switching between the opposite anaglyph statuses, a full-color anaglyph is presented. A liquid crystal panel from a 3D monitor serves as an active color filter operating at 120 Hz. A display panel and a color filter are connected to one graphic card as a dual-link system, for synchronization. To test the quality of this system, a left/right-eye image separation test and an experiment with stereoscopic images were carried out. Although there was some crosstalk and blur, the system, as expected, provided full-color 3D display. This system overcomes a monochromatic 3D image, which is the major weakness of the original anaglyph system.

Effects of Learning Motivation on the Stress Coping Style and Stress of Test (학습동기가 시험 스트레스와 스트레스 대처 양식에 미치는 영향)

  • Jang, Chel;Lee, Eunhye;Cheon, Jisu
    • Journal of The Korean Society of Integrative Medicine
    • /
    • v.2 no.2
    • /
    • pp.89-96
    • /
    • 2014
  • Purpose : In this study, we selected three research subjects to attempt to clear learning motivation of college students is what impact the stress coping style and stress test. First, age, gender, the future career after graduation, the presence or absence of part-time job is, its impact on learning motivation. Second, learning motivation is what effect the stress of the test. Third, based on the motivation of learning, how deal pursuing efforts form the social support, the center of the problem-solving approach, seeking to avoid the reaction to stress how different form. Methods : K University occupational therapy and one, two, three grade 100 students (male 22 people, female 78) to target age, sex, and after graduation, part-time status, motivation, stress, stress coping style questionnaire for distribution and was written. Results : First of all, women's social support form graduation course, more robust than pursue blank after the synchronization uncertainty and stress, and graduated from the trading center and avoid the use of career, more form. Second, motivation and stress test, a difference between the notice could not see. Third, the higher the motivation of learning, problem-solving, Action form to the center to use as many as you, but avoid using too much in the center form is addressed. Conclusion : As a result of the study that came out of the course after graduating from ensure that learning motivation is high, the more the uncertainty, the more to cope with stress in the center of the form to avoid form address was used. Because of this, the student careers after graduation, to make sure that can help you to compare efforts over is believed to be necessary.

Establishment of Test Field for Aerial Camera Calibration (항공 카메라 검정을 위한 테스트 필드 구축방안)

  • Lee, Jae-One;Yoon, Jong-Seong;Sin, Jin-Soo;Yun, Bu-Yeol
    • Journal of Korean Society for Geospatial Information Science
    • /
    • v.16 no.2
    • /
    • pp.67-76
    • /
    • 2008
  • Recently, one of the most outstanding technological characteristics of aerial survey is an application of Direct Georeferencing, which is based on the integration of main sensing sensors such as aerial camera or Lidar with positioning sensors GPS and IMU. In addition, a variety of digital aerial mapping cameras is developed and supplied with the verification of their technical superiority and applicability. In accordance with this requirement, the development of a multi-looking aerial photographing system is just making 3-D information acquisition and texture mapping possible for the dead areas arising from building side and high terrain variation where the use of traditional phptogrammetry is not valid. However, the development of a multi-looking camera integrating different sensors and multi-camera array causes some problems to conduct time synchronization among sensors and their geometric and radiometric calibration. The establishment of a test field for aerial sensor calibration is absolutely necessary to solve this problem. Therefore, this paper describes investigations for photogrammetric Test Field of foreign countries and suggest an establishment scheme for domestic test field.

  • PDF

An efficient acceleration algorithm of GPU ray tracing using CUDA (CUDA를 이용한 효과적인 GPU 광선추적 가속 알고리즘)

  • Ji, Joong-Hyun;Yun, Dong-Ho;Ko, Kwang-Hee
    • 한국HCI학회:학술대회논문집
    • /
    • 2009.02a
    • /
    • pp.469-474
    • /
    • 2009
  • This paper proposes an real time ray tracing system using optimized kd-tree traversal environment and ray/triangle intersection algorithm. The previous kd-tree traversal algorithms search for the upper nodes in a bottom-up manner. In a such way we need to revisit the already visited parent node or use redundant memory after failing to find the intersected primitives in the leaf node. Thus ray tracing for relatively complex scenes become more difficult. The new algorithm contains stacks implemented on GPU's local memory on CUDA framework, thus elegantly eliminate the problems of previous algorithms. After traversing the node we perform the latest CPU-based ray/triangle intersection algorithm 'Plucker coordinate test', which is further accelerated in massively parallel thanks to CUDA. Plucker test can drastically reduce the computational costs since it does not use barycentric coordinates but only simple test using the relations between a ray and the triangle edges. The entire system is consist of a single ray kernel simply and implemented without introduction of complicated synchronization or ray packets. Consequently our experiment shows the new algorithm can is roughly twice as faster as the previous.

  • PDF

Identification of Load Carrying and Vibration Characteristics of Oil-Free Foil Journal Bearing Structures for High Speed Motors (고속 전동기용 무급유 포일 저널 베어링 구조체의 하중지지 및 진동 특성 규명)

  • Baek, Doo San;Hwang, Sung Ho;Kim, Tae Ho
    • Tribology and Lubricants
    • /
    • v.37 no.6
    • /
    • pp.261-272
    • /
    • 2021
  • This study investigates the structural characteristics of oil-free, gas beam foil journal bearings (GBFJBs) for use in high speed motors. Mathematical modeling was carried out, and reaction force modeling for static load was performed to predict the structural characteristics of the GBFJB. Mathematical modeling and reaction force modeling for static load are performed to predict the structural characteristics of GBFJBs. The reaction force of the test bearing against static loads was measured during experiments and compared with the predicted results. The measured experimental data reveal the nonlinear stiffness characteristics of the GBFJB against varying displacement and agree well with the predictions. Dynamic load tests using an exciter allow to identify the vibration characteristics of the GBFJB. Test results show that the vibration displacement, dynamic force, and acceleration measured on the test bearing are most dominant at the applied dynamic load (synchronization) frequency. Futhermore, the test results show that the hysteresis area recorded during the dynamic tests increases with the excitation amplitude and frequency, and that the beam stick phenomena occurr at high excitation frequencies. The single degree of freedom (DOF) vibration model aids to identify the stiffness and damping coefficient of the GBFJB, which decrease as the excitation frequency increases.

Effect of Visual Biofeedback Simulation Training for Balance in Patients with Incomplete Spinal Cord Injury (시각적 바이오피드백 시뮬레이션훈련이 불완전 척수손상환자의 균형에 미치는 효과)

  • Park, Chang-Sik;Kang, Kwon-Young
    • The Journal of the Korea Contents Association
    • /
    • v.11 no.11
    • /
    • pp.194-203
    • /
    • 2011
  • This study investigated the effectiveness of visual biofeedback simulation training for patients with incomplete spinal cord injuries. Fifteen people with an ASIA impairment scale of C and D, according to the intervention method, were studied. They were randomly divided into two groups, seven people in the experimental group and eight people in the control group. They were studied three times a week for six weeks using a Tetrax Interactive Balance System, for a total of eighteen times, and each test took fifteen minutes. Paired t-tests were used to evaluate the changes before and after intervention. The difference between the groups was compared using an independent t-test. The experimental group showed significantly increased general stability, fall risk index, weight distribution (A, C, D, LEFT, HEEL) and weight distribution index, except for synchronization AC, BD. However, the control group only showed significantly increased weight distribution (A, C, LEFT). In a variation, experimental and control groups showed significantly increased weight distribution (A, B, C, HEEL), general stability, fall risk index and synchronization AD. Consequently, it was found that visual biofeedback simulation training was effective for the balance ability of incomplete spinal cord injury patients, and further studies are required.

Effect of Transcranial Direct Current Stimulation on Movement Variability in Repetitive - Simple Tapping Task

  • Kwon, Yong Hyun;Cho, Jeong Sun
    • The Journal of Korean Physical Therapy
    • /
    • v.27 no.1
    • /
    • pp.38-42
    • /
    • 2015
  • Purpose: Accuracy and variability of movement in daily life require synchronization of muscular activities through a specific chronological order of motor performance, which is controlled by higher neural substrates and/or lower motor centers. We attempted to investigate whether transcranial direct current stimulation (tDCS) over primary sensorimotor areas (SM1) could influence movement variability in healthy subjects, using a tapping task. Methods: Twenty six right-handed healthy subjects with no neurological or psychiatric disorders participated in this study. They were randomly and equally assigned to the real tDCS group or sham control group. Direct current with intensity of 1 mA was delivered over their right SM1 for 15 minutes. For estimation of movement variability before and after tDCS, tapping task was measured, and variability was calculated as standard deviation of the inter-tap interval (SD-ITI). Results: At the baseline test, there was no significant difference in SD-ITI between the two groups. In two-way ANOVA with repeated measurement no significant differences were found in a large main effect of group and interaction effect between two main factors (i.e., group factor and time factor (pre-post test)). However, significant findings were observed in a large main effect of the pre-post test. Conclusion: Our findings showed that the anodal tDCS over SM1 for 15 minutes with intensity of 1 mA could enhance consistency of motor execution in a repetitive-simple tapping task. We suggest that tDCS has potential as an adjuvant brain facilitator for improving rhythm and consistency of movement in healthy individuals.