• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.2
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• pp.313-322
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• 2000

The ATM Forum has been focusing on flow control mechanism for ABR traffic management. The goal of this activity is to efficiently manage the leftover network bandwidth and fairly distribute it among contending ABR VC so that communication links can be optimally utilized. ABR traffic is difficult to predict traffic shape because it has bursts and variable behavior. Also it's sensitive to lose but not to delay. This behavior makes difficult to UPC function in network and cause of congestion in switch, thus performance is degraded. To resolve this problem, various flow control mechanism has been worked in the ATM Forum. Especially, the rate-based flow control mechanism for ABR traffic has been standardized in the ATM Forum, Sept. 1994. Thus, various flow control mechanism has been working which likes EFCI, ER, VS/VD. VS/VD control is superior than existed ER control because it isolate different networks from each other. In this paper, we propose an expanded VS/VD flow control algorithm and compare with existed VS/VD flow control algorithm. Simulation result shows that this algorithm improve a problem in aspect of delay and fairness.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.8
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• pp.7-13
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• 2002

In this paper, we propose an traffic control algorithm for efficient link utilization of ATM-ABR service based on fuzzy logic. The proposed algorithm, controls transmission rates of source according to switch buffer size and input cell tate by using the fuzzy rate . For this method we developed a model and algorithm of fuzzy traffic control method and fuzzy traffic controller which based on ER of VS/VD. For the fuzzy traffic controller, we also designed a membership function, fuzzy control rules, and a max-min inferencing method.

• Science of Emotion and Sensibility
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• v.7 no.4
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• pp.67-75
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• 2004

In this paper, we analyze previous flow control algorithm for serving ABR traffic, and then propose the algorithm which calculate fair transmission rate and control efficiently ABR traffic using VS/VD switch which has an effect on PNNI environment with long delay. For getting the transmission rate, the proposed algorithm use FMMRA as ER scheme which calculate exactly the fair share. And, in large delay state, we can obtain fair cell sharing by calculating transmission rates which obtained by transmitted queue length information of VD to VS for serve and drain cell in queue Through the computer simulation, we evaluate the performance of proposed algorithm, According to the results, the proposed algorithm shows good performance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.5
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• pp.973-980
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• 2005

In this paper, we analyze previous flow control algorithm for serving ABR traffic, and then propose the algorithm which calculate fair transmission rate and control efficiently ABR traffic using VS/VD switch which has an effect on PNNI environment with long delay. For getting the transmission rate, the proposed algorithm use FMMRA as ER scheme which calculate exactly the fair share. And, in large delay state, we can obtain fair cell sharing by calculating transmission rates which obtained by transmitted queue length information of VD to VS for serve and drain cell in queue Through the computer simulation, we evaluate the performance of proposed algorithm. According to the results, the proposed algorithm shows good performance.

• Journal of the Korea Computer Industry Society
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• v.3 no.1
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• pp.85-94
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• 2002

EMRCA(Explicit Max_min Rate Control Algorithm) switch, which has been proposed in the ATM(Asychronous Transfer Mode) standard, controls the ABR(Available Bit Rate) service traffic in the ATM networks. The ABR service class of ATM networks uses a feedback control mechanism to adapt to varying link capacities. The VS/VD(Virtual Source/Virtual Destination) technique offers the possibility to segment the otherwise end-to-end ABR control loop into separate loops. The improved feedback delay and the control of ABR traffic inside closed segments provide a better performance and QoS(Quality of Service) for ABR connections with respect to throughput, delay, and jitter. This paper is study of an ABR VS/VD flow control method. Linear control theory offers the means to derive correct choices of parameters and to assess performance issues, like stability of the system, during the design phase. The performance goals are a high link utilization, fair bandwidth distribution and robust operation in various environments, which are verified by discrete event simulations. The major contribution of this work is the use of linear control theory to model and design an ABR flow control method tailored for the special layout of a VS/VD switch, the simulation shows that this techniques better than conventional method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9A
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• pp.1413-1421
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• 2000

In this paper, we analyze previous flow control algorithm for serving ABR traffic, and then propose the algorithm which calculate fair transmission rate and control efficiently ABR traffic using VS/VD switch which has an effect on WAN environment with long delay. For getting the transmission rate, the proposed algorithm use FMMAR as ER scheme which calculate exactly the fair share. And, in large delay state. we can obtain fair cell sharing by calculating transmission rates which obtained by transmitted queue length information of VD to VS for serve and drain cell in queue Through the computer simulation, we evaluate the performance of proposed algorithm. According to the results, the proposed algorithm shows good performance.

• The Journal of the Acoustical Society of Korea
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• v.18 no.6
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• pp.65-70
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• 1999

In ATM network there exist several traffics according to QoS, such as CBR, rt-VBR, nrt-VBR, UBR, and ABR. Many studies have done at the traffic management of ABR which uses the unused network bandwidth. Many flow control mechanisms have proposed to use efficiently the unused bandwidth. In TMWG(Traffic Management Working Group) of ATM Forum, there exist rate-based, credit-based, and mixture of them to manage flow control of ABR traffic. Among these, rate-based mechanisms adopted as standard because it is flexible and also makes it possible to implement ATM switch with low price and high capacity. In this paper, we study the switch that uses EFCI, ER and VS/VD(Virtual Source/Virtual Destination) with rate-based mechanism. Instead of using queue threshold, we propose a new algorithm which uses bandwidth threshold of input stage of switch, and manages efficiently ABR traffic with EPRCA algorithm.

• Korean Journal of Clinical Pharmacy
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• v.23 no.1
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• pp.33-41
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• 2013

Background: Prevalence of depression comorbid with neurologic disorders such as Alzheimer' disease (AD), Parkinson's disease (PD) and vascular dementia (VD) is higher than that of primary depression. Antidepressant medications, suggested by many researches for depression comorbid with neurologic disorders such as AD, PD and VD, are mainly selective serotonin reuptake inhibitors (SSRI). Objective: The primary objective of this study is the evaluation of antidepressant drug therapy for AD, PD and VD. Method: This study was a retrospective study based on medical records, carried out for 3 years and 6 months (Jan. 2007~Jul. 2010). Patients, diagnosed as comorbid depression through Beck Depression Inventory (BDI), Cornell Depression Scale (CDS), Geriatric Depression Scale (GDS) among neurologic out-patients of Chungnam National University Hospital because of AD, PD and VD, were selected. The results were evaluated by efficacy and safety of antidepressant drug therapy. Results: In result, the prescribing rates of antidepressants were 30%, 55% and 40% for each AD, PD and VD. Depression cure rates of patients receiving antidepressants vs patients not receiving antidepressants were 40% vs 39%, 33% vs 23% and 38% vs 30% for AD, PD and VD. The frequencies of prescriptoin of SSRI were 21%, 11% and 27% for each AD, PD and VD. The frequencies of prescriptoin of benzodiazepine (BZD) was 61%, 82% and 61% for each AD, PD and VD. The ratio of single BZD prescription was more than that of combination prescription of antidepressants. Tricyclic antidepressants (TCA) were rarely prescribed. The rate of patients with BZD-related side effects was 54%. The most frequent side effects of BZD were dizziness (30%), drowsiness (21%) and headache (16%). Side effects of SSRI were rare. Conclusion: In conclusion, the frequencies of prescription of antidepressants were not common for AD, PD and VD. There was little difference in depression cure rate between patient receiving antidepressants and not receiving. Even though SSRI has to be the highest priority of usage, the frequencies of prescription of SSRI were lower than those of BZD. Additional researches and efforts are required to improve antidepressant drug therapy for neurologic disorders such as AD, PD and VD.

• Journal of the Korea Society of Computer and Information
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• v.3 no.4
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• pp.132-138
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• 1998

A network of Asynchronous Transfer Mode (ATM) will be required to carry the traffics(CVR, VBR, UBR, ABR) generated by a wide range of services. The traffic ABR uses the remined space of the CBR/VBR traffics bandwith. The Rate-based, the Credit-based, and the mixed method that are implementing the control loop of ABR traffic service is on study. In this paper, a new algorithm that can be considered in ATM and effectively manage ABR traffic using VS/VD method and EPRCA algorithm is proposed on the switch of the Rate-based method

• The Transactions of the Korean Institute of Electrical Engineers
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• v.34 no.9
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• pp.355-360
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• 1985

In this paper, the discharge phenomena of high frequency glow discharge in organic vapor are basically investigted to establish the growth mechanism and preparation technique for organic thin film. According to the increasing of discharge frequency, the discharge firing voltage(Vs) of organic vapor decreases. The dependence of discharge voltage(Vd) on gas pressure is generally in accord with Paschen's Law and Vd decreases as gas flow rate become larger, but increases as dischange current density become higher. And the values of Vd in organic vapor are generally higher than those of inorganic gas.