• 한국콘텐츠학회논문지
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• 제10권3호
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• pp.44-52
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• 2010

인터넷에서 가장 많이 사용하고 있는 월드 와이드 웹(world wide web) 트래픽은 트랜스포트 계층 프로토콜로 TCP를 사용하고 있다. TCP는 단일 경로를 사용하므로 경로상의 링크가 다운(down)된 후 다시업(up)될 때까지의 시간동안 통신할 수 없다. 이에 비해 SCTP는 다중 경로를 사용하므로 1차 경로가 다운되어도 대체 경로를 이용하여 통신이 가능하다. TCP와 SCTP의 성능을 비교하는 기존 연구들은 주로 파일 전송을 사용하여 수행되었고, 링크다운 환경에서 웹 트래픽을 다룬 연구는 없었다. 자기-유사성의 특징을 갖는 웹 트래픽은 웹 파일의 크기에 영향을 주는 파레토 분포의 형태(shape) 파라미터와 평균 도착 시간간격에 의해 특징지어지므로 이 두 개의 파라미터에 따른 성능 비교가 필요하다. 따라서 본 연구에서는 링크다운 환경에서 웹 트래픽의 특성을 반영하는 두 개의 파라미터를 변화시키면서 TCP와 SCTP의 처리율을 비교하였다. NS-2 시뮬레이션을 사용한 웹 트래픽의 실험 결과는 멀티호밍을 사용한 SCTP의 처리율이 TCP의 처리율보다 우수함을 보여주었다. 특히 웹 트래픽의 특성과 관련해서는 TCP가 SCTP에 비해 평균 도착시간 간격과 형태 파라미터에 더 많은 영향을 받았다. 이 연구의 결과는 링크의 다운기간에 따른 웹 트래픽의 성능변화를 예측하는 데 이용될 수 있다.

• 전력전자학회논문지
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• 제22권4호
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• pp.336-344
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• 2017

This paper presents the three-port DC-DC converter modeling and controller design procedure, which is part of the solid-state transformer (SST) to interface medium voltage AC grid to bipolar DC distribution network. Due to the high primary side DC link voltage, the proposed converter employs the three-level neutral point clamped (NPC) topology at the primary side and 2-two level half bridge circuits for each DC distribution network. For the proposed converter particular structure, this paper conducts modeling the three winding transformer and the power transfer between each port. A decoupling method is adopted to simplify the power transfer model. The voltage controller design procedure is presented. In addition, the output current sharing controller is employed for current balancing between the parallel-connected secondary output ports. The proposed circuit and controller performance are verified by experimental results using a 30 kW prototype SST system.

• 디지털산업정보학회논문지
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• 제15권4호
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• pp.31-40
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• 2019

This paper proposes an adaptive PCIe system for TI C66x DSPs. Conventionally, the PCIe system provided by the C66x is a system dependent on the structure in which the primary core writes an application to the DSP memory through the PCIe interface, then activate the secondary core. Due to the dependency between the cores, when developing a project using a PCIe interface, the remaining cores have to be programmed with a concern of the primary core used as the PCIe interface. Therefore, in order to de-couple the connections among the cores, an adaptive PCIe system is proposed, in the paper, in which the cores operate independently compared to the conventional system. Since the core used as the PCIe interface only runs PCIe related operations in the new system, the remaining cores can be fully utilized without concerning the connections with the core for PCIe interface. In order to verify the feasibility of the proposed adaptive PCIe system, the implementations of LTE-A down link, and IEEE 802.11ac are carried out using the evaluation board which includes a TMS320C6670 chip. Altogether, these results support that we demonstrated that the digital signal processing systems with the PCIe Interface can be developed more rapidly by applying the proposed system.

• 한국간담췌외과학회지
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• 제27권3호
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• pp.241-250
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• 2023

Helicobacter pylori is a gram-negative pathogen commonly associated with peptic ulcer disease and gastric cancer. H. pylori infection has also been reported in cholelithiasis, cholecystitis, gallbladder polyps, and biliary tract cancers. However, the association between H. pylori and gallbladder and biliary tract pathologies remains unclear due to the paucity of literature. In response to the current literature gap, we aim to review and provide an updated summary of the association between H. pylori with gallbladder and biliary tract diseases and its impact on their clinical management. Relevant peer-reviewed studies were retrieved from Medline, PubMed, Embase, and Cochrane databases. We found that H. pylori infection was associated with cholelithiasis, chronic cholecystitis, biliary tract cancer, primary sclerosing cholangitis, and primary biliary cholangitis but not with gallbladder polyps. While causal links have been reported, prospective longitudinal studies are required to conclude the association between H. pylori and gallbladder pathologies. Clinicians should be aware of the implications that H. pylori infection has on the management of these diseases.

• 간호행정학회지
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• 제8권2호
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• pp.295-308
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• 2002

Purpose: The purpose of this quasi-experimental research is to develop the CP for primary THR patients and verify its effectiveness. Method: The CP is designed for both patients and medical employees to meet the 14-day-long hospitalization with an expert and clinical validity test, and the standardized orders are also created. 21 eligible subjects for the control group(with common care plan) and 27 subjects for the experimental group(with CP service) were assigned. Data were collected from questionnaires to evaluate patients' satisfaction level of nursing care and CP, investigation of physical complications, inspection of LOS(length of hospital stay) and hospital charges from April 2000 to February 2001 at K-hospital in Daegu. The collected data were analyzed by using the SAS program. Results: After implementation of CP, there was a statistically significant reduction in mean length of stay. The hospital charges have no considerable difference between two groups. Frequency of physical complications is reduced considerably. The experimental group scored much higher than the control group on the satisfaction level toward nursing care. And in the analysis of CP satisfaction questionnaires, many subjects have high satisfaction in items of 'I see the treatment process and hospital life', 'I feel that I am participating in my treatment process with health care staff'. The analysis of variances which cause a prolonged LOS supports that it's necessary to strengthen an evaluation of pre-operative outpatients' condition and link the home nursing care system in discharge for more shortening of LOS. Conclusion: The above results show that CP can have a positive impact on satisfaction level of inpatients with primary THR and the hospital.

• 한국인터넷방송통신학회논문지
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• 제13권6호
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• pp.101-108
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• 2013

본 논문에서는, NACK 메시지가 스펙트럼 공유와 협력을 위한 명령으로 사용되어지는 방법을 제안하였다. 1차 사용자의 직접 연결이 중단될 때, 협력과 공유의 자동 반복을 허가하고, 패러다임 기반의 협력 스펙트럼 공유의 조정 메시지의 수를 절약하기 위해 허가한다. 공유 시, ${\alpha}$의 남은 전력 부분이 1차 재전송 신호인 동안, 2차 전송된 신호를 위한 $1-{\alpha}$ 전력 부분은 중계기 공유로 선택된다. 중계기를 사용하지 않는 경우, 1차 송신단은 전체 전력($1-{\alpha}$)를 사용하여 신호를 재전송 하기 위해 NACK를 사용한다. 두 시스템은 BPSK 신호를 적용한 것으로 가정한다. 이 기법에서, 2차 사용자는 공동 최적화 복호를 하는 것으로 제안한다. 프레임 오류율(FER) 성능은 양 시스템에서 분석된다. 이론과 시뮬레이션 결과는 본 프로토콜의 유효성을 분석하고 효율적임을 확인하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(2)
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• pp.479-483
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• 2004

Fuel Cell (FC) has slow response characteristic for load variation. During a load step, the inverter cannot pull more power from the fuel cell than is currently available so supplemental power must be provide by some sort of energy storage elements. In this paper, hi-directional do-dc converter for FC generation system is proposed to improve load response characteristic. The hi-directional converter interfaces the low voltage battery to the inverter dc link of FC generation system. The converter is based on a active full bridge in the primary side and on a half bridge in the secondary of a high frequency isolation transformer. The complete operating principles and simulation results in presented.

• ETRI Journal
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• 제28권4호
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• pp.517-520
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• 2006

In this letter, a new sharing mechanism, SRLG sharing, is proposed, which allows the links of the same shared risk link group (SRLG) in a primary light tree to share protections in WDM optical networks. In previous studies, how to share spare resources with SRLG constraints has not been studied in multicast optical networks. In this letter, considering SRLG sharing, we propose a novel algorithm -multicast with SRLG sharing (MSS)- to establish a protection light tree. Finally, the algorithm MSS and the algorithm multicast with no SRLG sharing (MNSS) are compared through a simulation to show that our new sharing scheme of SRLG sharing is more efficient than that of no SRLG sharing in terms of spare resource utilization and blocking probability.

• ETRI Journal
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• 제34권4호
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• pp.492-502
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• 2012

We consider an overlaid broadcast service, where a spread spectrum (SS)-based broadcast signal is overlaid onto the existing terrestrial Digital Multimedia Broadcasting (T-DMB) band. The system is similar to the augmented data transmission in the ATSC DTV, for which it was investigated mostly in terms of link level performance, such as bit error rate. Our focus in this paper is on the system-level performances. More specifically, utilizing both a large scale path loss and a small scale fading channel model, the primary objective is to explore the tradeoff between the coverage and the achievable rate of the overlaid service and, finally, to determine the achievable rate in the overlaid service for marginal coverage reduction in the existing broadcast service. The analytical and simulation results show that an SS-based add-on service of 10 kbps to 20 kbps can co-exist with the T-DMB service while resulting in only a marginal degradation in T-DMB coverage (for example, less than one percent reduction).

• 대한안전경영과학회지
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• 제16권3호
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• pp.317-326
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• 2014

Slips and falls are associated with many public injuries in Korea. It is also estimated that slipping are major contributors to slip, trip and fall injury burden. The primary purpose of the present study is to determine if, and to what extent, the standard could be improved in present environment. In order to fulfill our objective, the regulations in Korea and foreign countries were investigated and reviewed. Many kind of standard, mandatory documents and guideline were also reviewed. And then, regulations, standard, guideline etc. reviewed were compared with each others. Also, some criteria was developed in this study. Standard and criteria developed in this study will help to prevent slip, trip, and fall injuries.