• Journal of Positioning, Navigation, and Timing
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• v.3 no.1
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• pp.31-36
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• 2014

Precise Point Positioning (PPP) is a stand-alone precise positioning approach. As the quality of satellite orbit and clock products from analysis centers has been improved, PPP can provide more precise positioning accuracy and reliability. A combined use of Global Positioning System (GPS) and Global Orbiting Navigation Satellite System (GLONASS) in PPP is now available. In this paper, we explained about an approach for combined GPS and GLONASS PPP measurement processing, and validated the performance through the comparison with GPS-only PPP results. We also used the measurement obtained from the GRAS reference station for the performance validation. As a result, we found that the combined GPS/GLONASS PPP can yield a more precise positioning than the GPS-only PPP.

• The Journal of the Korea Contents Association
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• v.5 no.3
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• pp.237-242
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• 2005

In this paper, a fast handoff algorithm between PDSNs in 3GPPx network for a mobile node, is proposed. It introduces a method by which handoff can be performed without reestablishing PPP connection that may occur in the process of performing handoff between PDSNs. When the PDSN recognizes the mobile node moving into its coverage area, it can quickly establish a communication channel with the mobile node based on the already received subscriber information. As a result, handoff is performed without reestablishing PPP. Accordingly, handoff between PDSNs can be performed faster, removing time needed for establishing a PPP session with a terminal and for terminating a previously set up PPP session.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.3
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• pp.159-168
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• 2021

Precise Point Positioning-Real Time Kinematic (PPP-RTK) is an improved PPP method that provides the user receiver with satellite code and phase bias correction information in addition to the satellite orbit and clock, thus enabling single-receiver ambiguity resolution. Single station PPP-RTK concept is special case of PPP-RTK in that corrections are computed, instead of a network, by only one single GNSS receiver. This study is performed to experimentally verify the positioning accuracy performance of single baseline RTK level by a user who utilizes correction for a single station PPP-RTK using dual frequencies. As an experimental result, the horizontal and vertical 95% accuracy was 2.2 cm, 4.4 cm, respectively, which verify the same performance as the single baseline RTK.

• Structural Engineering and Mechanics
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• v.89 no.6
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• pp.589-599
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• 2024

This study presents the usability of the high-rate single-frequency Precise Point Positioning (SF-PPP) technique based on 20 Hz Global Positioning Systems (GPS)-only observations in detecting dynamic motions. SF-PPP solutions were obtained from post-mission and real-time GNSS corrections. These include the International GNSS Service (IGS)-Final, IGS real-time (RT), real-time MADOCA (Multi-GNSS Advanced Demonstration tool for Orbit and Clock Analysis), and real-time products from the Australian/New Zealand satellite-based augmentation systems (SBAS, known as SouthPAN). SF-PPP results were compared with LVDT (Linear Variable Differential Transformer) sensor and single-frequency relative positioning (SF-RP) solutions. The findings show that the SF-PPP technique successfully detects the harmonic motions, and the real-time products-based PPP solutions were as accurate as the final post-mission products. In the frequency domain, all GNSS-based methods evaluated in this contribution correctly detect the dominant frequency of short-term harmonic oscillations, while the differences in the amplitude values corresponding to the peak frequency do not exceed 1.1 mm. However, evaluations in the time domain show that SF-PPP needs high-pass filtering to detect accurate displacement since SF-PPP solutions include trends and low-frequency fluctuations, mainly due to atmospheric effects. Findings obtained in the time domain indicate that final, real-time, and MADOCA-based PPP results capture short-term dynamic behaviors with an accuracy ranging from 3.4 mm to 8.5 mm, and SBAS-based PPP solutions have several times higher RMSE values compared to other methods. However, after high-pass filtering, the accuracies obtained from PPP methods decreased to a few mm. The outcomes demonstrate the potential of the high-rate SF-PPP method to reliably monitor structural and earthquake-induced ground motions and vibration frequencies of structures.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.5
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• pp.567-577
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• 2003

We usually applied PPP CHAP (Point-to-Point Protocol Challenge Handshake Authentication Protocol) when the visited ISP subscriber accesses to authentication server in own home ISP network and IP Assignment for remote Internet service. But PPP CHAP doesn't support in case of visited ISP subscriber in GPRS network accesses to authentication server in own home ISP network for wireless Internet service. We suggest solution this problem with PPP CHAP improvement. For this we propose the modified PPP CHAP message format, PCO Message format at MT, and interworking message and format between GGSN and RADIUS in home ISP network for wireless internet service of mobile ISP subscriber at GPRS network in this paper. We also show authentication results when visited mobile ISP subscriber via PPP CHAP at GPRS network accesses the RADIUS server in home ISP network.

• Korean Journal of Biological Psychiatry
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• v.8 no.1
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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.

• Journal of Positioning, Navigation, and Timing
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• v.4 no.2
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• pp.73-77
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• 2015

Global Positioning System (GPS) Precise Point Positioning (PPP) has been extensively used for geodetic applications. Since December 2012, BeiDou navigation satellite system has provided regional positioning, navigation and timing (PNT) services over the Asia-Pacific region. Recently, many studies on BeiDou system have been conducted, particularly in the area of precise orbit determination and precise positioning. In this paper PPP method based on BeiDou observations are presented. GPS and BeiDou data obtained from Mokpo (MKPO) station are processed using the Korea Astronomy and Space Science Institute Global Navigation Satellite System (GNSS) PPP software. The positions are derived from the GPS PPP, BeiDou B₁/B₂ PPP and BeiDou B₁/B₃ PPP, respectively. The position errors on BeiDou PPP show a mean bias < 2 cm in the east and north components and approximately 3 cm in the vertical component. It indicates that BeiDou PPP is ready for the precise positioning applications in the Asia-Pacific region. In addition, BeiDou tropospheric zenith total delay (ZTD) is compared to GPS ZTD at MKPO station. The mean value of their difference is approximately 0.52 cm.

• Journal of Construction Engineering and Project Management
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• v.3 no.2
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• pp.35-48
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• 2013

Weak competencies in urban local bodies (ULBs) for implementing public private partnership (PPP) projects has been recognized as a major hurdle in uptake of PPP model in India. In this context, a questionnaire survey was conducted to evaluate perception of urban PPP experts and ULB representatives on three aspects related to competency development, including, critical competencies for implementing urban PPP projects, approaches for competency development in ULBs and constraints faced by ULBs in development of competencies. The five critical competencies identified are project identification, project conceptualization, transaction design, PPP process management and contract management. The approach of training programs for municipal staff and elected representatives, and capacity building oriented technical assistance for implementing urban PPP projects have been preferred by survey respondents for competency development. The frequent transfer of municipal decision makers and low motivation among municipal staff have been identified as the most significant constraints for development of competencies.

• Journal of Positioning, Navigation, and Timing
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• v.6 no.4
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• pp.205-210
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• 2017

Multi-Global Navigation Satellite System (GNSS) can significantly improve the positioning accuracy and convergence speed. The reliability and availability of multi-GNSS precise point positioning (PPP) is steadily increasing with the rapid development of GNSS satellites. In this study, multi-GNSS PPP analysis is performed to compare the positioning precision by processing the observations from different GNSS systems (GPS, GLONASS, Galileo and BeiDou). To improve the positioning performance of the multi-GNSS PPP, we employed the weighed measurement noise (WMN) method. After applying WMN method to multi-GNSS PPP, positioning precision is improved by approximately 26.3% compared to the GPS only solutions, and by approximately 9.1% compared to combined GPS, GLONASS, and Galileo PPP.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.3
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• pp.41-49
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• 2018

Recently, PPP (Public-Private-Partnership) Projects, which private companies invest in, plan, design, construct and operate, have become more popular around the world. The construction industry environment is becoming increasingly competitive. The PPP project is composed of various organizations, so it is very difficult to carry out the project successfully. In this environment, the construction companies are trying hard to secure a competitive advantage. In this study, we tried to identify the role of project manager's leadership and project citizenship behavior as a precedent for creating performance in PPP (Private-Public-Partnership) project. We examine the impact of PM's transformational leadership and transactional leadership on project citizen behavior and examine the impact of project citizen action on project management performance and completion performance. For this study, we conducted a questionnaire survey on PPP project participants. As a result, the following results were obtained. First, transformational leadership and transactional leadership had a significant influence on project citizenship behavior. Second, project citizen behavior had a significant impact on both project management performance and project completion performance. The idealized influence of transformational leadership and the Active management by exception of transactional leadership were found to be very important in shaping PPP team's project citizenship behavior. Therefore, this study has academic implications in studying the effects of PM leadership and project citizenship behavior on the performance of PPP project. And it is expected that it will help selection and training of PM to secure a competitive advantage for construction companies that implement PPP projects practically.