• Title/Summary/Keyword: Switch model

Search Result 443, Processing Time 0.024 seconds

A cell scheduling of a logically separated buffer in ATM switch (ATM 스위치에서 논리적으로 분할된 버퍼의 셀 스케쥴링)

  • 구창회;나지하;박권철;박광채
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.22 no.8
    • /
    • pp.1755-1764
    • /
    • 1997
  • In this paper, we proposed the mechanism for the buffer allocation and a cell scheduling method with logical separation a single buffer in the ATm switch, and analyzed the cell loss probability and the delay of each trafic (CBR/VBR/ABR) based on the weighted value and the dynamic cell service scheduling algorithm. The proposed switch buffering system classifies composite trafics incoming to the switch, according to the characteristic of traffic, then stores them in the logically separated buffers, and adopts the round-robin service with weighted value in order to transmit cells in buffers though one output port. We analyzed 4 cell service scheduling algorithms with dynamic round-robinfor each logically separated service line of a single buffer, in which buffers have the respective weighted values and 3 classes on mixed traffic which characteristized by traffic descriptor. In simulation, using SIMCRIPT II.5., we model the VBR and the ABR traffics as ON/OFF processes, and the CBR traffic as a Poisson processes. As the results of analysis according to the proposed buffer management mechanism and cell service algorithm, we have found that the required QoS of each VC can be quaranteed depends on a scale of weighted values allocated to buffers that changed the weighted values, and cell scheduling algorithm.

  • PDF

Activating transcription factor 4 aggravates angiotensin II-induced cell dysfunction in human vascular aortic smooth muscle cells via transcriptionally activating fibroblast growth factor 21

  • Tao, Ke;Li, Ming;Gu, Xuefeng;Wang, Ming;Qian, Tianwei;Hu, Lijun;Li, Jiang
    • The Korean Journal of Physiology and Pharmacology
    • /
    • v.26 no.5
    • /
    • pp.347-355
    • /
    • 2022
  • Abdominal aortic aneurysm (AAA) is a life-threatening disorder worldwide. Fibroblast growth factor 21 (FGF21) was shown to display a high level in the plasma of patients with AAA; however, its detailed functions underlying AAA pathogenesis are unclear. An in vitro AAA model was established in human aortic vascular smooth muscle cells (HASMCs) by angiotensin II (Ang-II) stimulation. Cell counting kit-8, wound healing, and Transwell assays were utilized for measuring cell proliferation and migration. RT-qPCR was used for detecting mRNA expression of FGF21 and activating transcription factor 4 (ATF4). Western blotting was utilized for assessing protein levels of FGF21, ATF4, and markers for the contractile phenotype of HASMCs. ChIP and luciferase reporter assays were implemented for identifying the binding relation between AFT4 and FGF21 promoters. FGF21 and ATF4 were both upregulated in Ang-II-treated HASMCs. Knocking down FGF21 attenuated Ang-II-induced proliferation, migration, and phenotype switch of HASMCs. ATF4 activated FGF21 transcription by binding to its promoter. FGF21 overexpression reversed AFT4 silencing-mediated inhibition of cell proliferation, migration, and phenotype switch. ATF4 transcriptionally upregulates FGF21 to promote the proliferation, migration, and phenotype switch of Ang-II-treated HASMCs.

Topics in TFT device physics and modelling

  • Migliorato, P.
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 2005.07b
    • /
    • pp.929-935
    • /
    • 2005
  • This paper contains a review of methods to analise static and dynamic properties of trap states in TFTs. The Gap Density of States is extracted from C-V and I-V characteristics. Switch on transients and small signal ac measurements are used in conjunction with simulation and an analytic model to extract traps dynamic parameters.

  • PDF

Failure analysis of the T-S-T switch network

  • Lee, Kang-Won
    • Korean Management Science Review
    • /
    • v.11 no.1
    • /
    • pp.187-196
    • /
    • 1994
  • Time-Space-Time(T-S-T) switching network is modeled as a graceful degrading system. Call blocking probability is defined as a measure of performance. Several performance related measures are suggested under the presence of failure. An optimization model is proposed, which determines optimal values of system parameters of the switching network.

  • PDF

A Design of Fire-Command Synchronous Satellite Pyrotechnic Circuit (점화 명령에 동조된 인공위성 파이로테크닉 회로 설계)

  • Koo, Ja Chun;Ra, Sung Woong
    • Journal of Korea Society of Industrial Information Systems
    • /
    • v.18 no.5
    • /
    • pp.81-92
    • /
    • 2013
  • The satellite includes many release mechanisms such as solar array deployment, antenna deployment, cover to protect contamination in scientific equipment, pyro value of the propulsion subsytem, and bypass device in Li-Ion cell module. A drive the initiators is a critical to the successful mission because the initiators of release mechanism driving by the pyrotechnic circuit is operated in single short. The pyrotechnic circuit has to provide switching network for safety. A typical switching network has defect consisting of high current rating fire switch to handle switching transient current during fire the initiator. The pyrotechnic circuit is required some form of power conditioning to reduce the peak power demanded from the bus if the initiators are to be fired from the main bus. This paper design a pyrotechnic circuit synchronized to the fire-command to activate the fire switch to overcome use high current rating fire switch to handle switching transient current during fire the initiator. The pyrotechnic circuit provides a current limited widow pulse for fire current synchronized to the fire-command to insure that fire switch will only carry the current but never switch it. The current limited widow pulse for fire current can be possible to use low current rating and light mass switch in switching network. The current limit function in the pyrotechnic circuit reduces supply voltage to initiator and provides the effect of power conditioning function to reduce peak bus power. The pyrotechnic circuit to apply satellite development on geostationary orbit is verified the function by test in development model.

Finite Control Set Model Predictive Current Control for a Cascaded Multilevel Inverter

  • Razia Sultana, W.;Sahoo, Sarat Kumar
    • Journal of Electrical Engineering and Technology
    • /
    • v.11 no.6
    • /
    • pp.1674-1683
    • /
    • 2016
  • In this paper, a Finite Control Set Model Predictive Control (FCS-MPC) for a five level cascaded multilevel inverter (CMLI) with reduced switch topology is proposed. Five switches are used here instead of conventionally used eight switches. The main contribution of this paper is to make the MPC controller work for the reduced switch topology using only 19 voltage vectors in place of conventional 61 voltage vectors for a five level CMLI. This simplifies the execution of the MPC algorithm, paving a way for the significant reduction in the computational time. The controller makes use of the excellent ability of MPC to multitask, by adding one more objective which is to reduce the average switching frequency in addition to controlling the load current. This is especially important, since switching losses and therefore switching frequency is significant for high-power applications. The trade-off of this MPC is that the current is not as smooth as the 61 vector scheme, but well within the limits of IEEE standards. The results shown prove that this MPC works well in steady state and dynamic conditions too.

Performance of Dynamic Spectrum Access Scheme Using Embedded Markov Chain (임베디드 마르코프 체인을 이용한 동적 스펙트럼 접속 방식의 성능 분석)

  • Lee, Yutae
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.17 no.9
    • /
    • pp.2036-2040
    • /
    • 2013
  • In this paper, we consider two dynamic spectrum access schemes in cognitive network with two independent and identically distributed channels. Under the first scheme, secondary users switch channel only after transmission failure. On the other hand, under the second one, they switch channel only after successful transmission. We develop a mathematical model to investigate the performance of the second one and analyze the model using 3-dimensional embedded Markov chain. Numerical results and simulations are presented to compare between the two schemes.

Issues of Workplace in Korea: How to Inspire Temporary Workers?

  • Yang, Hoe-Chang;Khan, Tasnuva
    • Asian Journal of Business Environment
    • /
    • v.3 no.1
    • /
    • pp.23-27
    • /
    • 2013
  • Purpose - This study will focus on motivation of temporary workers working in distributors as well as generic companies, especially MPS (motivating potential score) proposed by job characteristics model. We think that temporary workers required intrinsic motivation in order to commit with their organization because they are difficult switch-regular workers due to glass ceiling. Research design, data, methodology - This study operates a survey targeting temporary workers, specifically, we used 144 copies except uncollected copies and dishonesty response of total 165 copies on analysis. We used multiple regression and 3 step regression to investigate the proposed model. Results - The high level of perceived distributional justice and procedural justice was increased the level of organizational commitment, respectively. And, MPS was increased the level of organizational commitment, too. Finally, this study showed that both justice and Job characteristics were very important to increase organizational commitment. Conclusions - In order to inspire temporary workers, the company provides placing enough considering job characteristics as well as fairness of the procedure and distribution. Also, to more fully understand the underlying processes between HRM (Human Resource Management) concepts, new fundamental methods may be required such as switch full-time opportunities.

  • PDF

A Study on the Efficiency Characteristics of the Interleaved CRM PFC using GaN FET (GaN FET를 적용한 인터리브 CRM PFC의 효율특성에 관한 연구)

  • Ahn, Tae-Young;Jang, Jin-Haeng;Gil, Yong-Man
    • The Transactions of the Korean Institute of Power Electronics
    • /
    • v.20 no.1
    • /
    • pp.65-71
    • /
    • 2015
  • This paper presents the efficiency analysis of a critical current mode interleaved PFC rectifier, in which each of three different semiconductor switches is employed as the active switch. The Si FET, SiC FET, and GaN FET are consecutively used with the prototype PFC rectifier, and the efficiency of the PFC rectifier with each different semiconductor switch is analyzed. An equivalent circuit model of the PFC rectifier, which incorporates all the internal losses of the PFC rectifier, is developed. The rms values of the current waveforms main circuit components are calculated. By adapting the rms current waveforms to the equivalent model, all the losses are broken down and individually analyzed to assess the conduction loss, switching loss, and magnetic loss in the PFC rectifier. This study revealed that the GaN FET offers the highest overall efficiency with the least loss among the three switching devices. The GaN FET yields 96% efficiency at 90 V input and 97.6% efficiency at 240 V, under full load condition. This paper also confirmed that the efficiency of the three switching devices largely depends on the turn-on resistance and parasitic capacitance of the respective switching devices.