• Title/Summary/Keyword: overhead measurement

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Version-Aware Cooperative Caching for Multi-Node Rendering

  • Cho, Kyungwoon;Bahn, Hyokyung
    • International Journal of Internet, Broadcasting and Communication
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    • v.14 no.2
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    • pp.30-35
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    • 2022
  • Rendering is widely used for visual effects in animations and movies. Although rendering is computing-intensive, we observe that it accompanies heavy I/O because of large input data. This becomes technical hurdles for multi-node rendering performed on public cloud nodes. To reduce the overhead of data transmission in multi-node rendering, this paper analyzes the characteristics of rendering workloads, and presents the cooperative caching scheme for multi-node rendering. Our caching scheme has the function of synchronization between original data in local storage and cached data in rendering nodes, and the cached data are shared between multiple rendering nodes. We perform measurement experiments in real system environments and show that the proposed cooperative caching scheme improves the conventional caching scheme used in the network file system by 27% on average.

A Experiment Study on Selection the Optimal Condition for GMA Root-pass Welding in Overhead and Vertical Position (GMA 위보기 및 수직자세 초층용접 최적조건 선정에 관한 실험적 연구)

  • Kim, Ji-Sun;Kim, In-Ju;Kim, Ill-Soo
    • Journal of Welding and Joining
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    • v.30 no.6
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    • pp.42-48
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    • 2012
  • Due to increase in demand of stable and long pipelines in natural gas industry, wide range of researches are being performed on automation welding to improved welding quality with respect to weld process parameters in real time measurement. In particular, the coupling between the pipe manufacturing process and location of the weld seam, the measured size of the gap that exists in the weld position and the weld angle depending on whether the movement of molten weld. This is due to absence of controlling welding penetration position, depending on the required size of the angle of the setting. In addition, the optimum welding conditions must be considered while selecting, the correlation between these variables and the systematic correlation has not yet been identified. Therefore, in most welded pipe root-pass weld solely depends on the experience of workers in relation to secure a stable weld quality. In this study, automation welding system is implemented to select a suitable root-pass STT (Surface Tension Transfer) welding method using the optimal welding conditions. To successfully accomplish this objective, there were various welding conditions used for welding experiment to confirm that the assessment required for construction through the pipe and automatic welding process is proposed to optimize this plan.

An Implement of Vision based Measurement Technology for Traction Power System up to 250 km/h (250 km/h급 전철설비의 비전기반 검측 기술 구현)

  • Park, Young-Sig;Na, Kyung-Min;Park, Young
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.7
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    • pp.976-980
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    • 2018
  • The traction power system is configured to transmit electricity to the vehicles through mechanical contact between the OCL (Overhead Contact Line) and the pantograph. The system measures the current collection performance of the OCL, or the OCL installation condition is examined through maintenance for commercial operation. Maintenance continues to check the conditions through visual inspection by walking and inspection vehicles. The current collection performance is divided into the percentage of arcing(%), the contact force, and the uplift. The percentage of arcing is composed of a vision based system and used to verify the performance of a new OCL. However, it is not always possible to measure the current collection performance during commercial operation, and maintenance based on human resources can not be replaced. This paper presents the minimum performance condition of video devices in the current collection system of commercial vehicles. In addition, a continuous arcing was measured, and current collection performance was examined on the traction power system at the 250 km/h. It was analyzed with a minimum duration of arc of 1 ms. The frame rate is then shown by comparing the number of frames in the image at the time intervals of the number of the arcing. It is expected that the result of this study can be used for examining the minimum performance of video devices depending on their purpose.

Performance Evaluation of Directional AODV Routing Protocol for Wireless Mesh Networks (무선 메쉬 네트워크를 위한 방향섬 AODV 라우팅 프로토콜의 성능 평가)

  • Choi, Jae-In;Kim, Dae-Hwan;Le, Anh Ngoc;Lee, In-Soo;Cho, You-Ze
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.9B
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    • pp.795-801
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    • 2008
  • Wireless Mesh Networks (WMNs) are popular due to their low cost and rapid deployment. Currently, many WMN researchers often considers the use of ad-hoc routing protocols because WMNs are similar to the ad-hoc networks. Some of currently deployed WMNs consider to use on-demand routing protocols such as Ad-hoc On-demand Distance Vector (AODV) and Dynamic Source Routing (DSR). But, AODV are not appropriate for Wireless Mesh Networks (WMNs), because flooding-based route discovery is both redundant and expensive in terms of control message overhead. In this paper, we propose a directional AODV (D-AODV) routing protocol based on hop count to a gateway. We implement the D-AODV routing protocol and evaluate the performance of the D-AODV on the testbed. The measurement results show that the D-AODV can enhance the network throughput by reducing the routing overhead.

The Efficacy of Active Exercise Programs for Work-Related Chronic Low Back Pain (직업성 만성요통에 대한 능동적 운동프로그램의 효과)

  • Hur, Jin-Gang
    • Journal of Korean Physical Therapy Science
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    • v.11 no.3
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    • pp.38-48
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    • 2004
  • The purpose of present study is to examine the relative efficacy of active exercise programs for work-related chronic low back pain and to figure out how much they affect mechanical stability of lumbar. Subjects are 43 employees with work-related chronic low hack pain, and they were randomly divided into two groups with general physiotherapy groups and thoracic exercise groups for increasing thoracic mobility. Active exercise programs were done 3 times a week, for 6 months, and the subjects were tested for Pain intensity(VAS), the Oswestry Disability Index, Maximal stretching with both hands in the overhead direction and the lumbar region angle of inclination. All subjects were reassessed with same measurement with Pre-study and 6 months after study After applying active exercise programs, pain intensity didn't show any significant difference between two groups. The Oswestry Disability Index showed significant difference between two groups and thoracic exercise groups decreased significantly compare to general physiotherapy group(p<0.05). Maximal stretching with both hands in the overhead direction showed significant difference between two groups and thoracic exercise group increased significantly more than general physiotherapy groups(p<0.05). The lumbar region angle of inclination showed significant difference between two groups and thoracic exercise group decreased significantly more than general physiotherapy groups (p<0.05). According to the results above, exercise for increasing thoracic mobility has an effect on lumbar stability. For the work-related chronic lower hack pain workers, it is far more effective for lumbar stabilization than general physiotherapy.

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Development of a Technique for Detection of Contact Wire Wear using High-Speed Camera (고속카메라를 이용한 전차선 마모 검측 영상처리 알고리즘 개발)

  • Park, Young;Cho, Yong-Hyeon;Cho, Chul-Jin;Kim, Won-Ha
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.8
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    • pp.632-637
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    • 2010
  • The measurement of contact wire wear in electric railways is one of the key test parameters to increase speed and maintain safety in electric railways. Wear caused by continuous interaction between pantographs and contact wires has a negative effect on current collection quality and severely damaged contact wires might cause hazardous accidents. This paper introduces a non-contact optical-based contact wire wear measuring system that will replace conventional wear detecting methods conducted by maintenance vehicles or workers. The system is implemented by high-speed cameras that can collect images of contact wires during vehicle operation, a laser used to create images profile of the contact wire surface, and a computer used to process the collected images. The proposed system is designed to assist maintenance of overhead contact lines by creating geometrically plotted images of contact wires to detect contact wire wear during operation on conventional lines or high-speed lines.

Application of Adaptive Neuro-Fuzzy Inference System for Interference Management in Heterogeneous Network

  • Palanisamy, Padmaloshani;Sivaraj, Nirmala
    • ETRI Journal
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    • v.40 no.3
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    • pp.318-329
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    • 2018
  • Femtocell (FC) technology envisaged as a cost-effective approach to attain better indoor coverage of mobile voice and data service. Deployment of FCs over macrocell forms a heterogeneous network. In urban areas, the key factor limits the successful deployment of FCs is inter-cell interference (ICI), which severely affects the performance of victim users. Autonomous FC transmission power setting is one straightforward way for coordinating ICI in the downlink. Application of intelligent control using soft computing techniques has not yet explored well for wireless networks. In this work, autonomous FC transmission power setting strategy using Adaptive Neuro Fuzzy Inference System is proposed. The main advantage of the proposed method is zero signaling overhead, reduced computational complexity and bare minimum delay in performing power setting of FC base station because only the periodic channel measurement reports fed back by the user equipment are needed. System level simulation results validate the effectiveness of the proposed method by providing much better throughput, even under high interference activation scenario and cell edge users can be prevented from going outage.

Analysis and Measurement of Lightning Parameters on Subscriber Telecommunication Lines (가입자 통신 선로에서의 뇌격 파라미터 분석과 측정)

  • Oh, Ho-Seok;Park, Dong-Chul
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.18 no.11
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    • pp.1309-1317
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    • 2007
  • In this paper, the Induced voltage on transmission line by lightning was calculated using FDTD method and the lightning parameters such as peak voltage, rise time, and decay time for the lightning location and line length were analyzed. To verify the results, lightning induced voltage was measured in the field using real telecommunication line. Results from the collected data were compared with the calculated results. It was found that the rise time and the decay time were increased as the line length and the distance between the line and lightning location were increased. Also, the peak voltage was affected more by the overhead line length than by the total line length, while the rise time and the decay time were more affected by the total line length.

An Analytic Method for Measuring Accurate Fundamental Frequency Components (기본파 성분의 정확한 측정을 위한 해석적 방법)

  • Nam, Sun-Yeol;Gang, Sang-Hui;Park, Jong-Geun
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.51 no.4
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    • pp.175-182
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    • 2002
  • This paper proposes an analytic method for measuring the accurate fundamental frequency component of a fault current signal distorted with a DC-offset, a characteristic frequency component, and harmonics. The proposed algorithm is composed of four stages: sine filer, linear filter, Prony's method, and measurement. The sine filter and the linear filter eliminate harmonics and the fundamental frequency component, respectively. Then Prony's method is used to estimate the parameters of the DC-offset and the characteristic frequency component. Finally, the fundamental frequency component is measured by compensating the sine-filtered signal with the estimated parameters. The performance evaluation of the proposed method is presented for a-phase to around faults on a 345 kV 200 km overhead transmission line. The EMTP is used to generate fault current signals under different fault locations and fault inception angles. It is shown that the analytic method accurately measures the fundamental frequency component regardless of the characteristic frequency component as well as the DC-offset.

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
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    • 2008.06a
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    • pp.89-90
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    • 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.

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