• Journal of KIISE:Information Networking
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• v.29 no.1
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• pp.40-47
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• 2002

This paper analyzes the performance of an optical line termination system in ATM based Passive Optical Network(PON) using the operational analysis. We analyze it using system parameters such as utilization, throughput and routing frequency based on the buffer structure in each block of ATM-PON. Furthermore, we derive the mean response time and the visit ratio of each block, and then search the bottleneck block that hinders the system performance. We found that the 622Mbps 16x16 switching block is the bottleneck block for ATM-PON. In this bottleneck block, the loss probability increases rapidly when the cell arrival rate increases.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.12
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• pp.1303-1309
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• 2012

In this paper, we propose a handover scheme for seamless mobile multicast service in next generation access networks. For this, we drew optimum handover scheme when applying MIP(mobile IP), FMIP(Fast MIP), HMIP(Heterogeneous MIP), PMIP(Proxy MIP) to XG-PON1. And, we analyze handover scheme for seamless mobile multicast service in XG-PON1. The prosed handover scheme remove tunnel convergence and reduces handover delay, packet delivery cost.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.5 s.347
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• pp.51-58
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• 2006

A variety of systems have been attempted for effective urban management. In this paper we introduce the Integrated Urban Management System (IUMS), which consists mainly of an optical line terminal (OLT), optical network terminals (ONTs) and wireless access points (APs), by combining passive optical network (PON) and radio over fiber (RoF) technologies so as to take advantage of both systems. Further, several IUMS services such as a disaster detection and prevention system (DDPS), a bus information system (BIS) and a real time location system (RTLS) we demonstrated in order to verify the employment of IUMS for the realization of a future ubiquitous city (U-city).

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.2
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• pp.128-137
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• 1999

Recently the pelionnance of CO2 arc welding machine has been advanced significantly through the adoption of i invelter circuit topology. which made it possible to improve welding perfonnances such as spatter generation and bead s state. But the conventional inverter arc welding machine generates constant output voltage which cause much spatter g generation dUling short-circuit and arc start time because it is unable to control output current instantaneously. So this p paper representes wavefCnm controlled inverter arc welding machine which control the wavefonn of welding current and t thus to suppress the spatter generation. And the system designed in this paper is the digital controller using single chip m microprocessor of 80C196KC. As a result of perfonnance test for this system, the spatter generation is reduced and s shOlt-circuit time period is stabilized compared to conventional one. And more by using switched mode rectifier for A AC/DC power convelter. unity power factor is maintained and low order halmonic spectrum is supressed.

• Korean Journal of Optics and Photonics
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• v.20 no.3
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• pp.143-147
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• 2009

We propose an asymmetrical 2.5 Gbps / 622 Mbps bidirectional optical subscriber network with Manchester coded downstream and NRZ (Non-Return-to-Zero) upstream remodulation. The proposed system has important characteristics in the optical network unit (ONU): it does not require a light source or the usual control circuits such as wavelength control and output power control, and it is possible to use a synchronization scheme between upstream and downstream data. We theoretically analyze BER(Bit Error Rate) performance of upstream data remodulated with Manchester coded downstream according to the types of NRZ downstream data and perform simulations with MATLAB. The BER performance and the receiver sensitivity have been improved by 3 dB by adjusting threshold levels compared to the conventional receiver. The results have shown the remodulation scheme with Manchester coded downstream could be a useful technology for asynchronous and asymmetric optical subscriber networks with low cost and simple structures.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.3 s.357
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• pp.68-77
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• 2007

In this paper, we address TPS (Triple Play Service) based on E-PON and also develop QoS control function for both directions, which is disadvantage of E-PON. E-PON technology has the configuration suitable for TPS, but relatively the large delay characteristics in upstream, so if QoS control function must be supported to transfer the real time traffic for both directions, E-PON technology can support TPS efficiently. Therefore, in this paper, we address the diverse requirements of quality for TPS, and then develop TPS platform to verify the quality characteristics according to QoS characteristics of each element in real environment based on this. This result will be used to improve the quality of TPS that become conventional in near future. ISP will use this result as the basis in establishing quality reference and as the guidance in developing new system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7A
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• pp.535-541
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• 2005

This paper proposes a hybrid optical lines composed of single-mode fiber(SMF) and multi-mode fiber(MMF) for gigabit-capable Passive Optical Network(GPON) using a WDM method with a single light source per each channel, and reports the results of transmission performance the proposed lines. The transmission link uses a direct modulated DFB-LD for high speed downstreams at the optical line terminal(OLT) of central office(CO) and a low cost SFP type transceiver for low-speed upstream in optical network unit(ONU). To split or combine the transmission channels, wavelength MUX/DEMUX are used in the optical line section, and MMFs not longer than 1 km are attached to the SMF lines at the ONU side of the WDM-PON links. We have performed the transmission experiment on the downstream of 2.5 Gbit/s, and 1.25 Gbit/s, and the upstream of 1.25 Gbit/s, and 622 Mbit/s which are recommended by ITU-T G.984.2. The transmission margin and feasibility of the proposed links have been tested to be suitable up to 2.5 Gbit/s transmission.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.7B
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• pp.422-430
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• 2007

WDM-PON has been receiving much attention as a key technology to FTTH. As the cost of WDM-PON heavily depends on the number of transceivers implemented at ONU, one of its shortcomings comes from the fixed provision of wavelength resource, which is tightly coupled with costly transceivers. In this paper, we propose a cost-effective WDM-PON architecture for dynamic resource provision. The proposed architecture is based on hierarchical grouping of multiple ONUs into a logical group and hierarchical sharing the resource. For high utilization of dynamic resource, the dynamic resource allocation algorithm is also proposed. We analyze the system efficiency in term of dynamism of system resource and system cost. We also verify that the proposed resource allocation algorithm achieves a high dynamism on resource allocation, and at the same time maintains the fairness between ONUs.

• The Journal of Internal Korean Medicine
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• v.34 no.4
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• pp.405-411
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• 2013

Objectives : This study was designed to investigate the difference between genuine and pseudo halitosis about qi stagnation and stress. Methods : We recruited 63 halitosis patients who visited the halitosis clinic in the Kyung Hee University Korean Medicine Hospital from June 2012 to August 2013. We classified the halitosis patients into two groups, genuine and pseudo halitosis based on organoleptic assesment (OLT) score and evaluated the severity of self-reported halitosis using visual analog scale (VAS), amount of sulfide compounds using Halimeter, qi stagnation level using qi stagnation questionnaire and stress levels using heart rate variability (HRV) parameters. Results : Comparing the genuine halitosis group and the pseudo halitosis group, there was no significant difference in VAS of halitosis but significant difference in halimeter score. Distribution of qi stagnation and non-qi stagnation groups was significantly different between genuine and pseudo halitosis. Compared to the genuine halitosis group, the pseudo halitosis group showed a significant higher value of low frequency/high frequency ratio (LF/HF ratio). Conclusions : The result of this study suggest that there is significant difference about qi stagnation and stress level between genuine halitosis and pseudo halitosis patients, so when approaching pseudo halitosis patients, we should consider their psychological and emotional status.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.4
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• pp.2321-2323
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• 2016

Background: Inflammatory hematological parameters like the neutrophil/lymphocyte (N/L) ratio have been investigated in many cancer types and significant relationships found with prognosis, for example. The aim of this present study was to investigate the impact of hematological parameters notably on N/L ratio and mean platelet volume (MPV) in papillary thyroid cancer cases. Materials and Methods: A total of 79 patients who underwent a thyroidectomy operation in Findikli, Goiter Research and Treatment Center during 2011-2015 period were enrolled in the study, 41 with papillary thyroid cancer and 38 with benign goiter confirmed by pathological examination. We collected clinical and laboratory data for the patients from hospital records retrospectively. Blood samples taken at admission were assessed for parameters compared between the groups. Results: No significant differences between papillary thyroid cancer and benign goiter groups were apparent in terms of age, the N/L ratio, MPV, white blood cell count (WBC), red blood cell count (RBC), hemoglobin, hematocrit, platelet, neutrophil, lymphocyte, red blood cell distribution width (RDW) and platelet crit (PCT) levels (p>0.05). Only the level of platelet distribution width (PDW) significantly differed, being lower in the papillary cancer group (p<0.05). Conclusions: No significant relationship between papillary thyroid cancer and inflammatory hematological parameters including in particular the N/L ratio and MPV. The relevance of the PDW values remains unclear.