• Title, Summary, Keyword: TRC

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Evaluation of Packet Loss Rate in Optical Burst Switching equipped with Optic Delay Lines Buffer

  • To, Hoang-Linh;Bui, Dang-Quang;Hwang, Won-Joo
    • Proceedings of the Korea Multimedia Society Conference
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    • pp.166-167
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    • 2012
  • High packet loss rate and impatience of messages passing through optical switches are essential characteristics in Optical Burst Switching system equipped with Optic Delay Lines buffer, which have not been solved efficiently yet by current existing models. In order to capture both effects, this paper introduces an analytical model from the viewpoint of classical queuing theory with impatient customers. We then apply it to evaluate and compare two wavelength-sharing cases, (1) all delay lines share a common wavelength resource and (2) each wavelength is associated with a number of delay lines. Our numerical results suggest to implement the first case because of lower packet loss rate for a fairly broad range of traffic load.

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Enhanced Production of Succinic Acid by Metabolically Engineered Escherichia coli with Amplified Activities of Malic Enzyme and Fumarase

  • Hong, Soon-Ho;Lee, Sang-Yup
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.9 no.4
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    • pp.252-255
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    • 2004
  • A pfl ldhA double mutant Escherichia coli strain NZN 111 was used to produce succinic acid by overexpressing the E. coli malic enzyme gene (sfcA). This strain, however, produced a large amount of malic acid as well as succinic acid. After the analyses of the metabolic pathways, the fumB gene encoding the anaerobic fumarase of E. coli was co-amplified to solve the problem of malic acid accumulation. A plasmid, pTrcMLFu, was constructed, which contains an artificial operon (sfcA-fumB) under the control of the inducible trc promoter. From the batch culture of recombinant E. coli NZN 111 harboring pTrcMLFu, 7 g/L of succinic acid was produced from 20 g/L of glucose, with no accumulation of malic acid. From the metabolic flux analysis the strain was found under reducing power limiting conditions by severe reorientation of metabolic fluxes.

Performance Evaluation for Multicasting Video over OpenFlow-based Small-scale Network

  • Thi, Thuyen Minh;Huynh, Thong;Kong, In-Yeup;Hwang, Won-Joo
    • Journal of Korea Multimedia Society
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    • v.17 no.9
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    • pp.1084-1091
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    • 2014
  • When demand for transmitting multimedia data increases, network congestion is more likely to occur and users will suffer high loss rate as well as high delay. In order to enhance quality-of-service (QoS) of video multicasting, we need to raise transmission reliability and reduce end-to-end delay. This paper proposes a routing mechanism for a OpenFlow-based small-scale network in order to multicast video reliably with low delay. In our method, multipath routing will be applied to Multiple Description (MD) Coded video to exploit its multi-description property. Through performance evaluation, our method shows improvement on loss rate, delay and video distortion.

The characteristic analyses and output frequency tracking control of a high frequency inverter (고주파 인버터의 특성해석 및 출력주파수 추종제어)

  • 이종무;김영석;조기연
    • 제어로봇시스템학회:학술대회논문집
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    • pp.597-602
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    • 1987
  • This paper proposes a voltage-fed high frequency resonant inverter having variable voltage variable frequency(VVVF) control function. VVVF control is performed by PWM-TRC method in the boost type chopper and PFM-TRC method in the high frequency resonant inverter. This circuit is suitable for induction heating and melting power supply in industry. The operating characteristics of this inverter are discussed from a theoretical point of view. The results of operating characteristic analyses are given leading to complete designing data.

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General AIMD with Congestion Window Upper Bound

  • Bui, Dang-Quang;Choi, Myeong-Gil;Hwang, Won-Joo
    • Journal of Korea Multimedia Society
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    • v.13 no.12
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    • pp.1798-1804
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    • 2010
  • TCP with AIMD mechanism, one of the most popular protocols in internet, can solve congestion control in wired networks. This protocol, however, is not efficient in wireless networks. This paper proposes a new mechanism namely General AIMD with Congestion Window Upper Bound in which congestion window is limited by an upper bound. By applying optimization theory, we find an optimal policy for congestion window upper bound to maximize network throughput.

Realtime 3D Human Full-Body Convergence Motion Capture using a Kinect Sensor (Kinect Sensor를 이용한 실시간 3D 인체 전신 융합 모션 캡처)

  • Kim, Sung-Ho
    • Journal of Digital Convergence
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    • v.14 no.1
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    • pp.189-194
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    • 2016
  • Recently, there is increasing demand for image processing technology while activated the use of equipments such as camera, camcorder and CCTV. In particular, research and development related to 3D image technology using the depth camera such as Kinect sensor has been more activated. Kinect sensor is a high-performance camera that can acquire a 3D human skeleton structure via a RGB, skeleton and depth image in real-time frame-by-frame. In this paper, we develop a system. This system captures the motion of a 3D human skeleton structure using the Kinect sensor. And this system can be stored by selecting the motion file format as trc and bvh that is used for general purposes. The system also has a function that converts TRC motion captured format file into BVH format. Finally, this paper confirms visually through the motion capture data viewer that motion data captured using the Kinect sensor is captured correctly.

Cold Cracking Susceptibility in Weld Metal of High Strength-Toughness Steel (고강도 고인성강 용접금속의 저온균열 감수성에 관한 연구)

  • 이종봉;안상곤;안영호;김영우
    • Journal of Welding and Joining
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    • v.13 no.4
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    • pp.46-54
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    • 1995
  • The cold cracking susceptibility of a variety of weld metals deposited by GMAW with several kinds of commercial solid wires for high strength-toughness steel was investigated. G-BOP test and LB-TRC test were carried out to study the effects of preheat, chemical composition and hydrogen level on the weld metal cold cracking. The results obtained are as follows. 1) 10% CPT obtained by G-BOP test was the most valuable criteria for evaluating the cold cracking susceptibility of weld metals compared with percentage of cracking at room temperature and crack free temperature, and it had good correlation with the results of LB-TRC test. 2) Cold cracking susceptibility of weld metals was high in the row of MG100A, MG100C, MG100D and MG100B. Welds deposited with MG130 and MG80 showed similar icidents of cracking with MG100C and MG100B respectively, even though their strength levels were different. 3) Diffusible hydrogen level in weld metals which has good relation with hydrogen content in wire itself was the most critical factor for controlling the cold cracking susceptibility of weld metal.

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용탕직접압연된 Al-Mg-Mn 합금판재의 기계적 특성

  • Kim, Hyeong-Uk;Kim, Min-Gyun;Im, Cha-Yong;Gang, Seok-Bong
    • Proceedings of the Materials Research Society of Korea Conference
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    • pp.43.2-43.2
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    • 2009
  • Al-Mg 알루미늄 합금은 강도가 높고 성형성이 우수하여 수송기기 경량화용 소재로서 사용량이 증가하고 있다. 특히고강도 특성을 보이는 Al-Mg-Mn합금은 자동차, 선박및 철도차량등의 형재 및 판재로 그 사용량이 증가하고 있다. 또한 결정립을 미세화 시킨 Al-Mg-Mn합금판재의 경우에는 온간성형으로 복잡한 형상의 판재부품제조에 사용되고 있다. 연속주조공정인 Twin roll strip casting(TRC)은용탕으로부터 직접 판재를 생산할 수 있는 공정으로 주로 순알루미늄계열의 판재 생산에 사용되고 있으나 최근에는 고강도 판재의 저비용 생산을 위하여 고합금계 판재에 적용하는 연구가 수행되고 있다. 합금량이 높은 고강도Al-Mg계 합금의 TRC 주조시 고액공존구간이 커서 더욱 정밀한 공정제어가 필요하다. 또한 기존의 슬라브주조방식보다 높은 냉각속도로 주조가 가능하기 때문에 결정립 및 정출상의 미세화공정으로 응용되기도한다. 본 연구에서는 TRC공정을 기초로 주조시 열간 압연의효과를 동시에 부여하는 용탕직접압연공정을 개발하였으며 상용 고강도 알루미늄 합금인 5083합금 판재를제조하였다. 또한 기존 Al-Mg 합금에 Mn을 첨가하여 용탕직접압연함으로서 정출상의 크기 및 밀도를 제어하여 강도가 우수한 Al-Mg-Mn 합금판재를 제조하는 기술을 개발하였다. 용탕직접압연된 Al-Mg-Mn계 합금의 경우에 주조시 높은 냉각속도로 인하여 결정립이 미세하고 Al6Mn과 같은 미세한 정출상이 다량 형성되었으며, 최종압연 및 열처리에 의하여 높은 강도를 갖는 고강도 알루미늄 합금 판재의 제조가 가능하였다.

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EVALUATION OF THE COLOR REPREDUCTION ON LCD MONITORS

  • Park, Seung-Ok;Kim, Hong-Suk;Lim, Yong-Jin;Yang, Jae-Youl
    • Proceedings of the Korean Society for Emotion and Sensibility Conference
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    • pp.407-411
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    • 2000
  • Color reproduction n CRT monitors needs colorimetric characterization concluding two stages with 3x3 matrix and three TRCs (Tone-Reproduction Characteristics). The 3x3 matrix is based on the additivity of RGB emissions, and the TRC represents the non-linearity between the input digital counts and the output luminance. The objective of this project is to evaluate the accuracy of color reproduction on LCD monitors using conventional CRT model(GOG model). For two different manufacturers, colorimetric characterizations of desktop LCDs have been performed. Because the transfer function for LCD is very differ from TRC of CRT, some researchers had reported that GOG model is inadequate for the colorimetric characterization of LCDs. However in our experiment, the degree of accuracy was dependent on the shape of electro-optical transfer functions of LCD. It has been founded that the GOG model could be applied for LCD monitors having monotonically increased Electro-optical transfer function.

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