• Title/Summary/Keyword: timing error

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An Empirical Study on the Truncated Arbitration System in China (중국의 결원중재제도에 관한 실증적 연구)

  • Ha, Hyun-Soo
    • Journal of Arbitration Studies
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    • v.31 no.4
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    • pp.51-70
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    • 2021
  • Chinese courts seem to be indifferent or ignorant of truncated arbitration. In other words, the Chinese court canceled the arbitration award made by truncated arbitration except for the Pingdingsan Case among the four arbitration cases related to the domestic arbitration award reviewed in this paper on the ground that it violated the composition of the arbitral tribunal or the arbitration procedure. A Chinese court has canceled the arbitration award by judging only based on the composition of the arbitral tribunal and the legal process of the violation of the arbitration procedure not by determining whether the domestic arbitration award made by the truncated arbitration meets the conditions for the application of truncated arbitration as stipulated in the Arbitration Rules. Moreover, it seems that the Chinese court made a serious error in the application of the relevant regulations in the Pingdingsan Case, which ruled that the truncated arbitration did not violate the legal process. In this case, the Chinese court admitted truncated arbitration under logic process that it was not necessary to wait until the final hearing to apply the truncated arbitraion because one arbitrator was absent before the final hearing, but the truncated arbitrator had already formed his/her opinion before the absence. However, in the case of Marshall Investment Corporation, a case related to foreign arbitration, the Chinese court rejected the approval and execution of the truncated arbitration award by strictly applying the laws and timing of the truncated arbitration. Since only one case has been identified in the main text, it is difficult to make a definitive judgment, but considering these cases, it seems to be that the Chinese courts apply different standards to domestic and foreign arbitration awards to determine the legality of truncated arbitration.

Effect of R-Z Relationships Derived from Disdrometer Data on Radar Rainfall Estimation during the Heavy Rain Event on 5 July 2005 (2005년 7월 5일 폭우 사례 시 우적계 R-Z 관계식이 레이더 강우 추정에 미치는 영향)

  • Lee, GyuWon;Kwon, Byung-Huk
    • Journal of the Korean earth science society
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    • v.33 no.7
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    • pp.596-607
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    • 2012
  • The R-Z relationship is one of important error factors to determine the accuracy of radar rainfall estimation. In this study, we have explored the effect of the R-Z relationships derived from disdrometer data in estimating the radar rainfall. The heavy rain event that produced flooding in St-Remi, Quebec, Canada has been occurred. We have tried to investigate the severity of rain for this event using high temporal (2.5 min) and spatial resolution ($1^{\circ}$ by 250 m) radar data obtained from the McGill S-band radar. Radar data revealed that the heavy rain cells pass directly over St-Remi while the coarse raingauge network was not sufficient to detect this rain event. The maximum 30 min (1 h) accumulation reaches about 39 (42) mm in St-Remi. During the rain event, the two disdrometers (POSS; Precipitation Occurrence Sensor System) were available: One used for the reflectivity calibration by comparing disdrometer Z and radar Z and the other for deriving disdrometric R-Z relationships. The result shows the significant improvement with the disdrometric reflectivity-dependent R-Z relationships against the climatological R-Z relationship. The bias in radar rain estimation is reduced from +12% to -2% and the root-mean squared error from 16 to 10% for daily accumulation. Using the estimated radar rainfall rate with disdrometric R-Z relationships, the flood event was well captured with proper timing and amount.

Compensation Analysis of Cell Delay Variation for ATM Transmission in the TDMA Method (TDMA 방식에서 ATM 전송을 위한 셀 지연 변이의 보상 해석)

  • Kim, Jeong-Ho;Choe, Gyeong-Su
    • The Transactions of the Korea Information Processing Society
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    • v.3 no.2
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    • pp.295-304
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    • 1996
  • Toprovide economical BISDN service, with which integration process of many types of media is possible, it is necessary to construct a system with ground network and satellite network combined. The method for this type of transmission using satellite is TDMA that can provide services to many users in various area. However, the most difficult task to connect TDMA which uses synchronous method to ATM which used asynchronous transfer mode is the deterioration n of ATM transmission quality such as cell delay variation. Therefore, it is necessary to develop delay variation compensation method which can confront to the ATM. Efficient ways to use satellite links under the conditions such that maximum efficiency of the delay variation is limited under the required value, and the burst characteristic of transmission cell does not increase are being researched for translation between in ATM and TDMA. This paper points out the problems when time stamp method, reviewd in ground network, is applied to the satellite links to compensate the delay variation .To solve the problem, discrete cell count method is introduced along with the calculation of transmission capacity and error rate.Also, from the observation of stab-ility of the system and verification of reliability even when singal error occurred in the cell transmission timing information, the proposed compensation method appeared to be excellent.

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A Rapid Signal Acquisition Scheme for Noncoherent UWB Systems (비동기식 초광대역 시스템을 위한 고속 신호 동기획득 기법)

  • Kim Jae-Woon;Yang Suck-Chel;Choi Sung-Soo;Shin Yo-An
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.4C
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    • pp.331-340
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    • 2006
  • In this Paper, we propose to extend the TSS-LS(Two-Step Search scheme with Linear search based Second step) scheme which was already proposed by the authors for coherent UWB(Ultra Wide Band) systems, to rapid and reliable acquisition of noncoherent UWB systems in multipath channels. The proposed noncoherent TSS-LS employing simple energy window banks utilizes two different thresholds and search windows to achieve fast acquisition. Furthermore, the linear search is adopted for the second step in the proposed scheme to correctly find the starting point in the range of effective delay spread of the multipath channels, and to obtain reliable BER(Bit Error Rate) performance of the noncoherent UWB systems. Simulation results with multipath channel models by IEEE 802.15.3a show that the proposed two-step search scheme can achieve significant reduction of the required mean acquisition time as compared to general search schemes. ]n addition, the proposed scheme achieves quite good BER performance for large signal-to-noise ratios, which is favorably comparable to the case of ideal perfect timing.

A Novel Scheme for Code Tracking Bias Mitigation in Band-Limited Global Navigation Satellite Systems (위성 기반 측위 시스템에서의 부호 추적편이 완화 기법)

  • Yoo, Seung-Soo;Kim, Sang-Hun;Yoon, Seok-Ho;Song, Iich-Ho;Kim, Sun-Yong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.10C
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    • pp.1032-1041
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    • 2007
  • The global navigation satellite system (GNSS), which is the core technique for the location based service, adopts the direct sequence/spread spectrum (DS/SS) as its modulation method. The success of a DS/SS system depends on the synchronization between the received and locally generated pseudo noise (PN) signals. As a step in the synchronization process, the tacking scheme performs fine adjustment to bring the phase difference between the two PN signals to zero. The most widely used tracking scheme is the delay locked loop with early minus late discriminator (EL-DLL). In the ideal case, the EL-DLL is the best estimator among various DLL. However, in the band-limited multipath environment, the EL-DLL has tracking bias. In this paper, the timing offset range of correlation function is divided into advanced offset range (AOR) and delayed offset range (DOR) centering around the correct synchronization time point. The tracking bias results from the following two reasons: symmetry distortion between correlation values in AOR and DOR, and mismatch between the time point corresponding to the maximum correlation value and the synchronization time point. The former and latter are named as the type I and type II tracking bias, respectively. In this paper, when the receiver has finite bandwidth in the presence of multipath signals, it is shown that the type II tracking bias becomes a more dominant error factor than the type I tracking bias, and the correlation values in AOR are not almost changed. Exploiting these characteristics, we propose a novel tracking bias mitigation scheme and demonstrate that the tracking accuracy of the proposed scheme is higher than that of the conventional scheme, both in the presence and absence of noise.

The study on the capacity of synchronous CDMA return link for a Ka band satellite communication system (Ka 대역을 사용하는 동기화 CDMA 위성 시스템 리턴링크의 수용용량에 관한 연구)

  • 황승훈;이용한;박용서;황금찬
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.23 no.7
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    • pp.1797-1806
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    • 1998
  • Future satellite communication systems will be developed at Ka-band (20/30 GHz) owing to the relatively wide frequency allocation and current freedom from terrestrial interference for multimedia services. A serious disadvantage of the Ka-band, however, is the very high atmospheric attenuation in rainy weather. Synchronous CDMA drastically redces the effect of self-noise with several interesting features of CDMA for mobile communications such as fixible freuqncy rese, the capability of performin soft-handover and a lower sensitivity to interference. This paper evaluates the performance of a synchronous CDMA reture link for a Ka-band geostationary satellite communication system. For a fixed satellite channel whose characteristics depend on weather conditions, the signal envelope and phase for this channel is modelled as Gaussian. The bit error and outage probability, and the detection loss due to imperfect chip timing synchronization is analytically evaluated and the system capacity degaradation due to the weather condition is estimated. The two cases consist of the general case in which all users are affected by rain condition, and the worst case in which the reference user is only affected by rain attenuation. the results for two cases of rain condition clearly show that synchronous CDMA eases the power control requirements and has less sensitivity to imperfect power control.

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The Design of 10-bit 200MS/s CMOS Parallel Pipeline A/D Converter (10-비트 200MS/s CMOS 병렬 파이프라인 아날로그/디지털 변환기의 설계)

  • Chung, Kang-Min
    • The KIPS Transactions:PartA
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    • v.11A no.2
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    • pp.195-202
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    • 2004
  • This paper introduces the design or parallel Pipeline high-speed analog-to-digital converter(ADC) for the high-resolution video applications which require very precise sampling. The overall architecture of the ADC consists of 4-channel parallel time-interleaved 10-bit pipeline ADC structure a]lowing 200MSample/s sampling speed which corresponds to 4-times improvement in sampling speed per channel. Key building blocks are composed of the front-end sample-and-hold amplifier(SHA), the dynamic comparator and the 2-stage full differential operational amplifier. The 1-bit DAC, comparator and gain-2 amplifier are used internally in each stage and they were integrated into single switched capacitor architecture allowing high speed operation as well as low power consumption. In this work, the gain of operational amplifier was enhanced significantly using negative resistance element. In the ADC, a delay line Is designed for each stage using D-flip flops to align the bit signals and minimize the timing error in the conversion. The converter has the power dissipation of 280㎽ at 3.3V power supply. Measured performance includes DNL and INL of +0.7/-0.6LSB, +0.9/-0.3LSB.

Enhanced Two-Step Search Scheme for Rapid and Reliable UWB Signal Acquisition (고속 고신뢰의 UWB 신호 동기획득을 위한 향상된 두 단계 탐색 기법)

  • Kim, Jae-Woon;Yang, Suck-Chel;Shin, Yo-An
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.12C
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    • pp.1133-1143
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    • 2005
  • In this paper, we propose an enhanced two-step search scheme for rapid and reliable signal acquisition in UWB systems under multipath channels. The proposed TSS-LS (Two-Step Search scheme with the Linear search based Second step) achieves rapid acquisition performance comparable to the conventional TSS-BS (Two-Step Search scheme with the Bit reversal search based Second step) already proposed by the authors, based on the single-dwell search with two-step thresholds and search windows. However, unlike the TSS-BS which employs the bit reversal search in the second step, the proposed TSS-LS utilizes the linear search in the second step to improve the reliability of signal acquisition. Simulation results with multipath channel models by IEEE 802.15.3a show that the two-step search schemes for the UWB signal acquisition can achieve sig nificant reduction of the required mean acquisition time as compared to general search schemes. In addition, we observe that the proposed TSS-LS achieves quite good bit error rate performance for large signal-to-noise ratios, which is favorably comparable to the case of ideal perfect timing.

Analysis of GPS Galileo Time Offset Effects on Positioning (GPS Galileo Time Offset (GGTO)의 항법해 영향 분석)

  • Joo, Jung-Min;Cho, Jeong-Ho;Heo, Moon-Beom
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37C no.12
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    • pp.1310-1317
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    • 2012
  • The Global Navigation Satellite System (GNSS) like US Global Positioning System (GPS) and EU Galileo are based on providing precise time and frequency synchronized ranging signals. Because of the exploitation of very precise timing signals these GNSS are used to provide both navigation and time distribution services. Moreover, because the positioning accuracy will improve as more satellites become available, we should expect that a combination of Galileo and GPS will provide better performance than those of both systems separately. However, Galileo will not use the same time reference as GPS and thus, a time difference arises - the GPS-Galileo Time Offset (GGTO). The navigation solution calculated by receivers using signals from both navigation systems will consequently contain a supplementary error if the GGTO is not accounted for. In this paper, we compared GPS Time (GPST) with Galileo Sytem Time (GST) and analyzed the effects of GGTO on positioning accuracy by simulation test. And then we also analyzed the characteristics of two representative GGTO correction methods such as the navigation message based method at system level and the estimation method at user level and propose the conceptual design of the novel correction method being capable of preventing previous method's problems.

Hypoalbuminemia and Albumin Replacement during Extracorporeal Membrane Oxygenation in Patients with Cardiogenic Shock

  • Jae Beom Jeon;Cho Hee Lee;Yongwhan Lim;Min-Chul Kim;Hwa Jin Cho;Do Wan Kim;Kyo Seon Lee;In Seok Jeong
    • Journal of Chest Surgery
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    • v.56 no.4
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    • pp.244-251
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    • 2023
  • Background: Extracorporeal membrane oxygenation (ECMO) has been widely used in patients with cardiorespiratory failure. The serum albumin level is an important prognostic marker in critically ill patients. We evaluated the efficacy of using pre-ECMO serum albumin levels to predict 30-day mortality in patients with cardiogenic shock (CS) who underwent venoarterial (VA) ECMO. Methods: We reviewed the medical records of 114 adult patients who underwent VA-ECMO between March 2021 and September 2022. The patients were divided into survivors and non-survivors. Clinical data before and during ECMO were compared. Results: Patients' mean age was 67.8±13.6 years, and 36 (31.6%) were female. The proportion of survival to discharge was 48.6% (n=56). Cox regression analysis showed that the pre-ECMO albumin level independently predicted 30-day mortality (hazard ratio, 0.25; 95% confidence interval [CI], 0.11-0.59; p=0.002). The area under the receiver operating characteristic curve of albumin levels (pre-ECMO) was 0.73 (standard error [SE], 0.05; 95% CI, 0.63-0.81; p<0.001; cut-off value=3.4 g/dL). Kaplan-Meier survival analysis showed that the cumulative 30-day mortality was significantly higher in patients with a pre-ECMO albumin level ≤3.4 g/dL than in those with a level >3.4 g/dL (68.9% vs. 23.8%, p<0.001). As the adjusted amount of albumin infused increased, the possibility of 30-day mortality also increased (coefficient=0.140; SE, 0.037; p<0.001). Conclusion: Hypoalbuminemia during ECMO was associated with higher mortality, even with higher amounts of albumin replacement, in patients with CS who underwent VA-ECMO. Further studies are needed to predict the timing of albumin replacement during ECMO.