http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
VLBI Type Experimental Observation of GPS
곽영희,Tetsuro Kondo,Jun Amagai,Tadahiro Gotoh,Tetsuo Sasao,조정호,김두환 한국우주과학회 2010 Journal of Astronomy and Space Sciences Vol.27 No.2
As a preparatory study for Global Positioning System-Very Long Baseline Interferometry (GPS-VLBI) hybrid system, we examined if VLBI type observation of the GPS signal is realizable through a test experiment. The test experiment was performed between Kashima and Koganei, Japan, with 110 km baseline. The GPS L1 and L2 signals were received by commercial GPS antennas, down-converted to video-band signals by specially developed GPS down converters, and then sampled by VLBI samplers. The sampled GPS data were recorded as ordinary VLBI data by VLBI recorders. The sampling frequency was 64 MHz and the observation time was 1 minute. The recorded data were correlated by a VLBI correlator. From correlation results, we simultaneously obtained correlation fringes from all 8 satellites above a cut-off elevation which was set to 15 degree. 87.5% of L1 fringes and 12.5% of L2 fringes acquired the Signal to Noise Ratios which are sufficient to achieve the group delay precision of 0.1nsec that is typical in current geodetic VLBI. This result shows that VLBI type observation of GPS satellites will be readily realized in future GPS-VLBI hybrid system.
한국 측지 VLBI 시스템을 위한 라운드 Trip 시스템
오홍종,Tetsuro Kondo,김두환,이진우,김명호,김수철,박진식,주현희 한국측량학회 2010 한국측량학회 학술대회자료집 Vol.2010 No.4
한국 측지 VLBI 시스템 건설 프로젝트는 2008년 11월에 공식적으로 시작되었으며, 2011년 말까지 완료하는 것을 목표로 하고 있다. 프로젝트의 공식 명칭은 한국 측지 VLBI 시스템(Korea VLBI system for Geodesy)이며 주목적은 한국측지 기준점을 유지 관리하는 것이다. KVG의 경우 수소 메이저 주파수 표준이 위치한 관측실은 안테나와 수십 m 떨어진 분리된 건물에 있다. 따라서 KVG는 위상 변동 효과가 축소된 기준신호를 안테나로 전달하는 라운드 trip 시스템을 갖출 것이다. KVG의 라운드 trip 시스템은 metal이나 광케이블을 모두 사용할 수 있을 뿐만 아니라 K5/VSSP32 샘플러를 이용하여 위상 변동을 직접적으로 측정하는 것도 가능하도록 설계되었다. 여기서는 라운드 trip 시스템의 기본원리와 KVG를 위한 새로운 타입의 라운드 trip 시스템을 소개할 것이다. A project for construction of Korea Geodetic VLBI has officially started in Oct. 2008. The construction of all system will be completed by the end of 2011. The project was named Korea VLBI system for Geodesy (KVG), and its main purpose is to maintain the Korea Geodetic Datum. In case of the KVG system, an observation room where an H-maser frequency standard is located is in a building separated from an antenna by several tens of meters. Therefore KVG system will adopt a so-called round-trip system to transmit reference signals to the antenna with diminishing the effect of path length variations. KVG"s round-trip system is designed not only available to use either metal or optical fiber cables, but also available to measure path length variations directly by using K5/VSSP32 sampler. We will present principle of round-trip system and the new type of round trip system for KVG.
A Comparison of Broadcast and Final Orbits on GPS Delays in GPS-VLBI Hybrid Observation
곽영희,조정호,Tetsuro Kondo,Jun Amagai,Tadahiro Gotoh,Mamoru Sekido,Ryuichi Ichikawa,김두환,Tetsuo Sasao 사단법인 항법시스템학회 2012 Journal of Positioning, Navigation, and Timing Vol.1 No.1
We carry out an error analysis of 24-hour global positioning system (GPS)-very long baseline interferometry (VLBI) (GV) hybrid observation data. In this paper, we focus on the impacts of broadcast and final orbits on the GPS delays of the GV hybrid observation by analyzing the residuals, observed - calculated (O-C) values. The residuals show apparent and consistent biases for L1 and L2 signals, respectively. The scatters of the residuals are around a few nanoseconds. The main cause of those observation errors is the absence of the GPS phase and delay calibration system. Most of the satellites show that the differences between the delays, to which broadcast and final orbits are applied, are about 100 times smaller than the current GV hybrid observation errors. We conclude that GPS delays are not greatly affected by orbit accuracies.
A Comparison of Broadcast and Final Orbits on GPS Delays in GPS-VLBI Hybrid Observation
Kwak, Younghee,Cho, Jungho,Kondo, Tetsuro,Takiguchi, Hiroshi,Amagai, Jun,Gotoh, Tadahiro,Sekido, Mamoru,Ichikawa, Ryuichi,Kim, Tuhwan,Sasao, Tetsuo The Institute of Positioning 2012 Journal of Positioning, Navigation, and Timing Vol.1 No.1
We carry out an error analysis of 24-hour global positioning system (GPS)-very long baseline interferometry (VLBI) (GV) hybrid observation data. In this paper, we focus on the impacts of broadcast and final orbits on the GPS delays of the GV hybrid observation by analyzing the residuals, observed - calculated (O-C) values. The residuals show apparent and consistent biases for L1 and L2 signals, respectively. The scatters of the residuals are around a few nanoseconds. The main cause of those observation errors is the absence of the GPS phase and delay calibration system. Most of the satellites show that the differences between the delays, to which broadcast and final orbits are applied, are about 100 times smaller than the current GV hybrid observation errors. We conclude that GPS delays are not greatly affected by orbit accuracies.
Takashi Motohashi,Akira Yabuno,Hiroshi Michimae,Tetsuro Ohishi,Miwa Nonaka,Masashi Takano,Shin Nishio,Hiroyuki Fujiwara,Keiichi Fujiwara,Eiji Kondo,Toru Sugiyama,Tsutomu Tabata 대한부인종양학회 2021 Journal of Gynecologic Oncology Vol.32 No.1
Objective: The standard dose for pegylated liposomal doxorubicin (PLD) is 50 mg/m2every 4weeks. While 40 mg/m2has recently been used in clinical practice, evidence supporting thisuse remains lacking. Methods: This phase III randomized, non-inferiority study compared progression free survival (PFS) for patients with platinum-resistant ovarian carcinoma between anexperimental arm (40 mg/m2PLD) and a standard arm (50 mg/m2PLD) until 10 courses,disease progression or unacceptable toxicity. Eligible patients had received ≤2 prior lines. Stratification was by performance status and PFS of prior chemotherapy (<3 months versus ≥3months). The primary endpoint was PFS and secondary endpoints were overall survival (OS),toxicity profile, clinical response and tolerability. The total number of patients was 470. Results: The trial was prematurely closed due to slow recruitment, with 272 patients randomizedto the experimental arm (n=137) and standard arm (n=135). Final analysis was performed with234 deaths and 269 events for PFS. In the experimental arm vs. standard arm, median PFS was4.0 months vs. 4.0 months (hazard ratio [HR]=1.065; 95% confidence interval [CI]=0.830–1.366)and median OS was 14.0 months vs. 14.0 months (HR=1.078; 95% CI=0.831–1.397). Hematologictoxicity and oral cavity mucositis (≥grade 2) were more frequent in the standard arm than in theexperimental arm, but no difference was seen in ≥grade 2 hand-foot skin reaction. Conclusion: Non-inferiority of 2 PLD dosing schedule was not confirmed because the trialwas closed prematurely. However, recommendation of dose reduction of PLD should bebased both on efficacy and safety. Trial Registration: UMIN Clinical Trials Registry Identifier: UMIN000003130