• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.474-479
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• 2011

With Beijing's success in bidding for the 2008 Olympic Games, the increasing demand for infrastructure development and reduced public sector funding capacity has created a significant funding gap which calls for alternative project delivery methods such as Public-Private Partnership (PPP). Although the exploration of infrastructure projects using PPP model have been practiced since the late 80s, the $560 million National Stadium which served as the main venue for the Olympic Games is the first stadium project in China to be delivered under PPP operation. The project is generally considered successful despite the concession transfer in 2009 with concern of better serving the public interest. Compared to other infrastructure projects such as transportation, waste management and water management, the development of major sports facilities for mega-sports events with PPP has its own unique features and is subject to different major risks. This research identifies and analyzes critical risks in the implementation of PPP in major sports facility development through case study of the National Stadium project. A questionnaire survey and several interviews are conducted to solicit expert opinions from experienced practitioners. The purpose is to provide additional insights in risk management strategies and opportunities in China's PPP implementations in major sports facilities for policy makers and private sectors involved with investment decisions in future similar infrastructure development.

• 한국건설관리학회논문집
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• 제19권2호
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• pp.83-95
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• 2018

본 논문은 민간투자사업의 특수성을 반영한 성과평가 모델 개발을 목적으로 한다. 성과평가 모델 개발을 위해 첫째, 문헌연구를 통하여 민간투자사업 주요 관점과 관점별 성공항목을 정의하고, AHP 설문조사를 통하여 가중치를 산정하였다. 둘째, 민간투자사업 성과에 영향을 미치는 핵심 성과요인을 도출하고, 이를 평가할 수 있는 평가항목을 제안하였다. 셋째, 관점별 성공항목과 평가항목을 매칭함으로써 민간투자사업 성과평가 모델을 구축하였다. 성과평가 모델 개발과 적용을 통해 민간투자사업 이해관계자 사이의 첨예한 관점의 차이가 존재함을 파악할 수 있었다. 이는 다양한 이해관계자의 관점을 균형있게 반영한 민간투자사업의 종합적인 평가의 필요성을 보여준다. 본 연구에서 제시한 성과평가 모델의 평가 결과와 기존의 건설공사 사후평가 결과를 비교해보면, 본 연구의 평가 점수가 이용자 만족도 조사 결과와 유사하다. 건설공사 사후평가에 비해 본 연구의 평가모델은 다양한 이해관계자의 만족도 및 관점을 반영하였기 때문으로 판단된다. 본 연구에서 개발한 성과지표의 결과를 통해 다양한 관점을 고려한 민간투자사업의 성과를 측정할 수 있으며, 어떠한 성공요인 및 평가항목이 프로젝트 성공에 영향을 미치는지 파악할 수 있다. 또한, 본 모델의 프로세스를 기반으로 주요관점 및 성공항목의 가중치 변화와 평가항목의 가감을 통해 도로 시설물을 제외한 민간투자사업 프로젝트에도 적용이 가능할 것으로 기대된다.

• 생물정신의학
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• 제8권1호
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• pp.79-84
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• 2001

Objectives : To investigate the effects of (-)-3-PPP(0.5, 2, and 10mg/kg, s.c.) and haloperidol(0.1, 0.5, and 2mg/kg, s.c.) on the extracellular dopamine concentrations, and the effect of pretreatment with (-)-3-PPP(2mg/kg) on the haloperidol(2mg/kg)-induced extracellular dopamine concentrations in the nucleus accumbens(NAS) of free moving rats. Methods : Dopamine levels in dialysate were determined with high pressure liquid chromatography(HPLC) with electrochemical detection(ECD). Results : (1)(-)-3-PPP had dual actions depending on the doses: at 2mg/kg, it decreased and at 10mg/kg, increased extracellular dopamine concentrations ; (2) haloperidol at all doses increased dopamine levels with higher dose having a greater increase; and (3) pretreatment of (-)-3-PPP reduced the increase in dopamine levels elicited by acute treatment with haloperidol. Conclusions : These findings suggest that pretreatment of (-)-3-PPP in low dose could accelerate the onset of therapeutic effect of haloperidol by diminishing the haloperidol-induced dopamine release in the limbic system.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2005년도 춘계 종합학술대회 논문집
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• pp.507-513
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• 2005

이 논문은 모바일 노드를 위해 3GPPx 네트워크와 PDSN 사이에 빠른 핸드오프 계획을 제안한다. 이 방법은 PDSN과 PPP 사이 핸드오프의 과정에 일어날 수 있는 단락을 안전하게 수행될 수 있게 하며, PDSN이 자신의 유효 범위내에 움직이는 모바일 교점을 다시 인식할 때, 모바일 노드의 통신 채널이 기존에 수신되었던 모바일 노드 정보에 의거하여 빠르게 확증 될 수 있는 시스템을 제공한다. 결과적으로, 핸드오프 과정에서는 PPP을 재연결하지 않고 수행되며, 이전에 설정된 PPP 세션을 끝내는 것과 터미널을 가지고 PPP 세션을 확증하는 것을 위해 필요했던 시간이 줄게 되고 PDSN과 모바일 노드 사이에 핸드오프 절차가 더 빨리 수행될 수 있다.

• 대한공간정보학회지
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• 제22권1호
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• pp.47-54
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• 2014

휴대용 단말에 간편하게 구현 가능하도록 GPS의 코드의사거리 관측치 기반의 정밀단독측위(PPP; Precise Point Positioning) 알고리즘을 개발하고 그 성능을 검증하였다. PPP에 필요한 기본 모델로 그룹 딜레이, 상대성 효과, 위성안테나 위상중심오프셋 보정모델을 적용하였다. 위성 궤도와 시계오차는 IGS(International GNSS Service) 공식 산출물에 최적의 알고리즘을 통해 보간하고, 대류권과 전리층 오차는 각각 과학기술용 GPS 자료처리 소프트웨어로 산출한 참값과 GIM(Global Ionosphere Model)을 사상함수를 적용해 시선방향 오차로 변환해 적용하였다. 개발된 알고리즘을 4일간 테스트한 결과 수평오차는 0.8~1.6m, 수직오차는 1.6~2.2m 수준으로 나타났다. 이는 DGPS 측위결과와 유사한 성능으로 향후 PPP 알고리즘의 추가개선이 이루어질 경우 다양한 측량 및 위치기반서비스 분야에 활용 가능할 것으로 기대된다.

• 한국전자파학회논문지
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• 제29권2호
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• pp.109-117
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• 2018

비선형적으로 회전하는 표적의 inverse synthetic aperture radar(ISAR) 영상을 형성하기 위해서는 표적의 수신 신호에 적절한 회전운동 보상기법을 수행해 주어야 한다. 대표적인 회전운동 보상기법인 prominent point processing(PPP)은 산란점의 위상정보를 이용하여 비선형 회전성분을 선형화하는 기법이다. 본 논문에서는 integrated cubic phase function(ICPF)을 이용하여 산란점의 위상정보를 추정한 다음 PPP를 수행하여 ISAR 영상을 형성하는 방법을 제안한다. ICPF는 다수의 산란점으로부터 중첩된 신호가 수신되었을 때 1차원 영역(domain)의 최댓값을 찾는 작업을 수행함으로써 산란점의 위상정보를 추정할 수 있다. 시뮬레이션 결과 ICPF를 이용한 산란점 위상정보 추정 후 PPP를 수행함으로써 지배적 산란점이 존재하지 않는 환경에서 실시간으로 높은 품질의 ISAR 영상을 획득하였다.

• 한국정보처리학회논문지
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• 제7권7호
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• pp.2135-2148
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• 2000

Developing network software in embedded systems, such as digital set-top boxes, requires coding under limited computing resources. This paper presents the porting of Point-to-point Protocol (PPP) software, PPPD, to an embedded system. The PPP is the most popular link layer protocol for the information appliance, to an embedded system. In order to achieve this, problems to be solved for the porting were identified and methods to solve the problems were described. First, PPP source codes were divided into modules. Next, functions of each module were analyzed and interfaces between the modules were delineated. With the analysis results, porting to the embedded system was described. The normal operation of the ported software was verified with the help of a network packet analyzer. Finally, experiences during the porting were presented. The method developed in th paper can be applied to the porting of software to an embedded system as well as the porting of network software.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -2
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• pp.695-698
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• 2000

The services such as real-time audio and video applications have become increasingly popular, especially over the Internet. Furthermore, as being commercialized those contents on the Internet require quality of service (QoS) support to ensure their performance. PPP is the best solution to of for those kinds of services. The reason why we want to employ PPP is this satisfies most of the requirements associated with remote connectivity to an NSP, such as IP address assignment, security, and AAA (authentication, authorization and accounting). In addition, since ISPs and corporations are familiar with PPP based connectivity, easy migration from existing ISP infrastructure is expected, if QoS is guaranteed. But so for PPP has had no field to ensure the quality of service. This article presents the solution by using some tunneling protocols and the draft [1] that proposed additional LCP option fields to negotiate QoS. To communicate each other, after negotiating those option fields, over various protocols such as ATM, Ethernet, and etc. tunneling protocol is used. Following sections will mention those briefly. And the service provision to offer the end-to-end communication with negotiated QoS will also be proposed.

• KDI Journal of Economic Policy
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• 제42권4호
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• pp.117-138
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• 2020

Few studies have specifically focused on the uncertainty of demand forecasting despite the fact that uncertainty is the one of greatest risks for governments and private partners in PPP projects. This study presents a methodology for finding robust contract conditions considering uncertainty in travel demand forecasting in a PPP project. Through a case study of an urban railway PPP project in Korea, this study uncovered the risk of excessive government payments to private partners due to the uncertainty in contracted forecast ridership levels. The results allow the suggestion that robust contract conditions could reduce the expected total level of government payments and lower user fees while maintaining profitability of the project. This study offers a framework that assists contract negotiators and gives them more information regarding financial risks and vulnerabilities and helps them to quantify the likelihood of these vulnerabilities coming into play during PPP projects.

• Journal of Positioning, Navigation, and Timing
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• 제12권2호
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• pp.141-148
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• 2023

In this paper, impacts of tropospheric delay gradient correction on PPP positioning performance were analyzed. A correction for tropospheric delay error due to the gradient was created and applied using external data, and reference station data were collected on a sunny day and a rainy day to analyze the GPS only dual-frequency PPP positioning results. As a result, on the sunny day, the convergence time was about 35 minutes and the final 3D position error was 10 cm, regardless of whether the correction for the tropospheric delay error by the gradient was applied. On the other hand, on the rainy day, the 3D position error converges only when the correction was applied, and the convergence time was about 34 minutes. Furthermore, the final 3D position error was improved from 30 cm to 10 cm. In addition, the analysis of the PPP by reference station location on the rainy day showed that the PPP positioning performance was improved when the correction was applied to a user located in an area where the weather changes.