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Einstein’s Concept of Clock Synchronization Conflicts with the Second Relativity Postulate

Journal of Modern Physics 2024年第7期15卷 985-1000页

作者： Steven D. Deines Donatech Corporation Inc. Fairfield Iowa USA

Einstein defined clock synchronization whenever photon pulses with timetags traverse a fixed distance between two clocks with equal time spans ineither direction. Using the second relativity postulate, he found clocksmounted on a rod uniformly moving parallel with the rod’s length cannot besynchronized, but clocks attached to a stationary rod can. He dismissed thisdiscrepancy by claiming simultaneity and clock synchronization were not commonbetween inertial frames, but this paper proves with both Galilean and Lorentztransformations that simultaneity and clock synchronization are preservedbetween inertial frames. His derivation means moving clocks can never besynchronized in a “resting” inertial frame. Ultraprecise atomic clocks intimekeeping labs daily contradict his results. No algebraic error occurred inEinstein’s derivations. The two cases of clocksattached to a rod reveal three major conflicts with the currentsecond postulate. The net velocity between a photon source and detector plusthe “universal” velocity c is mathematically equivalent toEinstein’s clock synchronization method. As the ultraprecise timekeepingcommunity daily synchronizes atomic clocks on the moving Earth withultraprecise time uncertainty well below Einstein’s lowest limit ofsynchronization, the theoretical resolution of the apparent conflict isaccomplished by expanding the second relativity postulate to inc.rporate thenet velocity between the photon source and detector with the emitted velocity c as components of the total velocity c. This means the magnitudeof the total photon velocity can exceed the speed limit (299792458 m/s) set by the standard velocity c. .

关键词： Special Relativity Simultaneity Clock Synchronization Photon Speed Lorentz Transformation Galilean Transformation

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Risk Assessments for Elderly Patients with Hip Arthro-plasty Using POSSUM and P-POSSUM

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Open Journal of Orthopedics 2013年第2期3卷 53-61页

作者： Yuancheng Li Hassan H. Dib Weiguo Zhang Xiao Zhang Department of Orthopedic Surgery First Affiliated Hospital of Dalian Medical University Dalian China Department of Radiology Dalian Central Hospital Dalian China. medicose health net inc. Richmond Hill Canada.

Background: The physiological and operative severity score for the enumeration of mortality and morbidity (POSSUM) is a scoring system previously validated in vascular and general surgical patients. The Portsmouth physiological and operative severity score for the enumeration of mortality and morbidity (P-POSSUM) is a reliable tool derived from POSSUM to improve the prediction of mortality. In this paper, we utilized both models to determine the most suitable and feasible one that could be utilized in orthopedic surgery in China mainland. Methods: In this retrospective study, patients’ files were extracted randomly from the medical records department of the First Hospital Affiliated with Dalian Medical University for those underwent hip replacements between 1999 and 2006. The mortality and morbidity rates were predicted by P-POSSUM and POSSUM, respectively. A comparative analysis was performed between the observed and the predicted values as well as the Observed/Expected ratio (O:E). Results: A total of 206 patients were selected for this study after fulfilling the inc.usion and exclusion criteria. The predicted mortality by P-POSSUM were not significantly different from the observed values (X2 = 2.10, P = 0.552). POSSUM appeared to be better with the observed morbidity (X2 = 2.766, P = 0.598), but had overestimated mortality. Conclusion: The POSSUM morbidity equation satisfactorily estimated the risk of postoperative complications, and the P-POSSUM mortality equation appeared to stratify the risk of death more accurate than the POSSUM.

关键词： Hip Arthroplasty Mortality Morbidity P-POSSUM POSSUM

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EXPERIMENTAL AND NUMERICAL INVESTIGATION OF BUBBLE AUGMENTED WATERJET PROPULSION

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Journal of Hydrodynamics 2012年第5期24卷 635-647页

作者： CHOI Jin-Keun SINGH Sowmitra HSIAO Chao-Tsung CHAHINE Georges L DYNAFLOW inc. JessupMarylandUSA

This contribution presents experimental and numerical investigations of the concept jet propulsion augmentation using bubble injection. A half-3D （D-shaped cylindrical configuration to enable optimal visualizations） divergent-convergent nozzle was designed, built, and used for extensive experiments under different air injection conditions and thrust measurement schemes. The design, optimization, and analysis were conducted using numerical simulations. The more advanced model was based on a two-way coupling between an Eulerian description of the flow field and a Lagrangian tracking of the injected bubbles using our Surface Averaged Pressure （SAP） model. The numerical results compare very favorably with nozzle experiments and both experiments and simulations validation the thrust augmentation concept. For a properly designed nozzle and air injection system, air injection produces net thrust augmentation, which inc.eases with the rate of bubble injection. Doubling of thrust was measured for a 50% air injection rate. This beneficial effect remains at 50% after account for liquid pump additional work to overcome inc.eased pressure by air injection.

关键词： waterjet propulsion bubble dynamics multi-phase flow

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Improving Performance of Virtual Machine Covert Timing Channel Through Optimized Run-Length Encoding

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Journal of Computer Science & Technology 2023年第4期38卷 793-806页

作者：王翀陈荣亮古亮 Shenzhen Institute of Advanced Technology Chinese Academy of SciencesShenzhen 518055China Sangfor Technologies inc. Shenzhen 518055China Shenzhen Key Laboratory for Exascale Engineering and Scientific Computing Shenzhen 518055China

With its wider acceptability,cloud can host a diverse set of data and applications ranging from entertainment to personal to *** foundation of cloud computing is based on virtual machines where boundaries among the application data are very thin,and the potential of data leakage exists all the *** instance,a virtual machine covert timing channel is an aggressive mechanism to leak confidential information through shared components or networks by violating isolation and security policies in *** performance of a covert timing channel(covert channel)is crucial to adversaries and attempts have been made to improve the performance of covert timing channels by advancing the encoding mechanism and covert information *** promising,the redundancy of the covert message is mainly *** paper applies three encoding schemes namely run-length,Huffman,and arithmetic encoding schemes for data compression of a virtual machine covert timing channel by exploiting ***,the paper studies the performance of such channels according to their ***,we show that these encoding schemes still contain redundancy in a covert channel scenario,and thereby a new encoding scheme namely optimized Runlength encoding(OptRLE)is presented that greatly enhances the performance of a covert timing *** optimizations schemes adopted by OptRLE are also discussed,and a mathematical model of the behavior of an OptRLE-based covert timing channel is *** theoretical capacity of a channel can be obtained using the proposed *** analysis reveals that OptRLE further improves the performance of a covert timing channel,in addition to the effects of the *** result shows how OptRLE affects the size of covert data and the capacity of covert timing channels,and why the performance of the covert timing channel is improved.

关键词： covert storage channel information security covert channel threat evaluation anti-detection criterion covert channel restriction

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Using real world data to assess cardiovascular outcomes of two antidiabetic treatment classes

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World Journal of Diabetes 2018年第12期9卷 252-257页

作者： Manfred Paul Stapff CMO TriNetX Inc.

AIM To evaluate the effect on cardiovascular outcomes of sodium-glucose co-transporter-2(SGLT2) inhibitors in a real world setting by analyzing electronic medical *** We used Tri net X, a global federated research network providing statistics on electronic health records(EHR). The analytics subset contained EHR from approximately 38 Million patients in 35 health Care Organizations in the United States. The records of 46,909 patients who had taken SGLT2 inhibitors were compared to 189,120 patients with dipeptidyl peptidase(DPP) 4 inhibitors. We identified five potential confounding factors and built respective strata: elderly, hypertension, chronic kidney disease(CKD), and co-medication with either insulin or metformin. Cardiovascular events were countedas stroke(ICD10 code: I63) or myocardial infarction(ICD10: I21) occurring within three years after the first instance of the respective medication in the patients' *** Of the 46909 patients with SGLT2 inhibitors in their EHR, 1667 patients(3.6%) had an ICD code for stroke or for myocardial infarction within the first three years after the first instance of the medication. In the control group, there were 10680 events of 189120 patients(5.6%), which represents a risk ratio of 0.63(95%CI: 0.60-0.66). The overall inc.dence of stroke or myocardial infarction in the strata with a potential confounding risk factor reached from 4.9% in patients taking metformin to 12.5% in the stratum with the highest risk(concomitant CKD). In all strata, the difference in risk of experiencing a cardiovascular event was similarly in favor of SGLT2 vs control, with Risk Ratio ranging from 0.62 to *** Real world data replicated the results from randomized clinical trials, confirmed the cardiovascular advantages of SGLT2 inhibitors, and showed its applicability to the US population.

关键词： Sodium-glucose co-transporter-2 inhibitors Cardiovascular events Clinical trials Electronic medical records Dipeptidyl peptidase 4 inhibitors Real world evidence Diabetes

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A systematic review of metabolism of methionine sources in animals:One parameter does not convey a comprehensive story

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Animal Nutrition 2023年第2期13卷 31-49页

作者： Philippe Becquet Mercedes Vazquez-Anon Yves Mercier Karen Wedekind Tahir Mahmood Dolores I.Batonon-Alavo Frances Yan International Methionine Analogue Association Regus Brussels City CentreStephanie SquareAvenue Louise65B-1050 BrusselsBelgium Novus International inc. 20 Research Park DriveSaint CharlesMissouri 63304USA Adisseo France SAS Antony Parc II10 Place Du General de GaulleAntony 92160France

The goal of this review article,based on a systematic literature search,is to critically assess the state of knowledge and experimental methodologies used to delineate the conversion and metabolism of the 2 methionine(Met)sources DL-methionine(DL-Met)and DL-2-hydroxy-4-(methylthio)butanoic acid(HMTBa).The difference in the chemical structures of HMTBa and DL-Met indicates that these molecules are absorbed and metabolized differently in *** review explores the methodologies used to describe the 2-step enzymatic conversion of the 3 enantiomers(D-HMTBa,L-HMTBa and D-Met)to L-Met,as well as the site of conversion at the organ and tissue *** work was published documenting the conversion of HMTBa and D-Met into L-Met and,consequently,the inc.rporation into protein using a variety of in vitro techniques,such as tissue homogenates,cell lines,primary cell lines,and everted gut sacs of individual *** studies illustrated the role of the liver,kidney,and intestine in the con-version of Met precursors into L-Met.A combination of in vivo studies using stable isotopes and infusions provided evidence of the wide conversion of HMTBa to L-Met by all tissues and how some tissues are net users of HMTBa,whereas others are net secreters of L-Met derived from *** of D-Met to L-Met in organs other than the liver and kidney is poorly *** methodology cited in the literature to determine conversion efficiency ranged from measurements of urinary,fecal,and respiratory excretion to plasma concentration and tissue inc.rporation of isotopes after intraperitoneal and oral *** observed between these methodologies reflect differences in the metabolism of Met sources rather than differences in conversion *** factors affecting conversion efficiency are explored in this paper and are mostly associated with extreme dietary conditions,such as noncommercial crystalline diets that are very deficient in total sulfur amino a

关键词： DL-Methionine Hydroxy-analog of methionine 2-Hydroxy-4-(methylthio)butanoic acid Conversion Metabolism Methodology

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Magnetic Inertial Confinement Fusion(MICF)

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Plasma Science and Technology 2016年第11期18卷 1055-1063页

作者：苗峰曾宪俊邓柏权刘伟欧巍黄毅 Institute of Atomic and Molecular Physics Sichuan University Southwest University for Nationalities HOPE Innovations inc. Southwestern Institute of Physics Institute of Nuclear Science and Technology Sichuan University

t Based on the similarity in models of the early Sun and the 3-D common focal region of the micro-pinc. in X-pinc. experiments, a novel hybrid fusion configuration by continuous focusing of multiple Z-pinc.ed plasma beams on spatially symmetric plasma is proposed. By replacing gravity with Lorentz force with subsequent centripetal spherical pinc., the beam- target fusion reactivity is enhanced in a quasi-spherical converging region, thus achieving MICF. An assessment, presented here, suggests that a practical fusion power source could be achieved using deuterium alone. Plasma instabilities can be suppressed by fast rotation resulting from an asymmetric tangential torsion in the spherical focal region of this configuration. Mathematical equivalence with the Sun allows the development of appropriate equations for the focal region of MICF, which are solved numerically to provide density, temperature and pressure distributions that produce net fusion energy output. An analysis of MICF physics and a preliminary experimental demonstration of a single beam are also carried out.

关键词： MICF centripetal spherical pinc. beam-target enhancement

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Near Optimal Output Feedback Control of Nonlinear Discrete-time Systems Based on Reinforcement Neural network Learning

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IEEE/CAA Journal of Automatica Sinica 2014年第4期1卷 372-384页

作者： Qiming Zhao Hao Xu Sarangapani Jagannathan the DENSO International America Inc. with the College of Science and Engineering Texas A&M University the Department of Electrical&Computer Engineering Missouri University of Science and Technology

In this paper, the output feedback based finitehorizon near optimal regulation of nonlinear affine discretetime systems with unknown system dynamics is considered by using neural networks(NNs) to approximate Hamilton-JacobiBellman(HJB) equation solution. First, a NN-based Luenberger observer is proposed to reconstruct both the system states and the control coefficient matrix. Next, reinforcement learning methodology with actor-critic structure is utilized to approximate the time-varying solution, referred to as the value function, of the HJB equation by using a NN. To properly satisfy the terminal constraint, a new error term is defined and inc.rporated in the NN update law so that the terminal constraint error is also minimized over time. The NN with constant weights and timedependent activation function is employed to approximate the time-varying value function which is subsequently utilized to generate the finite-horizon near optimal control policy due to NN reconstruction errors. The proposed scheme functions in a forward-in-time manner without offline training phase. Lyapunov analysis is used to investigate the stability of the overall closedloop system. Simulation results are given to show the effectiveness and feasibility of the proposed method.

关键词： Artificial neural networks Observers Optimal control Learning (artificial intelligence) Approximation methods Feedback Nonlinear dynamical systems

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Towards Optimal Transmission Switching in Day-Ahead Unit Commitment

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Journal of Power and Energy Engineering 2015年第4期3卷 97-105页

作者： Kwok W. Cheung Jun Wu Alstom Grid Inc. Redmond Washington USA

Co-optimizing transmission topology with generation dispatch, and leveraging grid controllability could be a viable way to improve economic efficiency of system operations in control centers. In particular, day-ahead unit commitment is a typical business process that electric utilities deploy to ensure enough generation capacity is committed day-ahead to meet the load for the next day. In a market environment, day-ahead reliability unit commitment (DA-RUC) performs a simultaneous solution of minimizing the cost of commitment for resources to meet forecasted load, net scheduled interchange and operating reserve requirements using security constrained unit commitment (SCUC). The commitment may then be further checked by running security constrained economic dispatch (SCED) to verify that the commitment solution can be feasibly dispatched subject to system constraints and activated transmission constraints for each hour identified in the study period. This paper applies Optimal Transmission Switching (OTS) in DA-RUC using some heuristic pre-screening techniques to reduce the dimension of the OTS problem. Various pre-screening methods of candidate transmission lines for switching are proposed and compared. Simulation results will be presented to demonstrate generation dispatch combined with OTS in each hour could reduce congestion cost and significantly lower generation cost.

关键词： Transmission Switching Market Efficiency System Operation Economic Dispatch

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Delta asymmetry:Concepts,characteristics,and depositional models

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Petroleum Science 2011年第3期8卷 278-289页

作者： Li Weiguo Janok P. Bhattacharya Wang Yingmin BP America inc. Houston Texas77079 USA Department of Earth and Atmospheric Sciences University of Houston Houston Texas 77204-5007 USA College of geosciences China University of Petroleum Beijing 102249 China

Delta asymmetry forms in wave-influenced settings where there is strong net longshore drift. Asymmetric deltas typically have two sediment sources and are characterized by morphology and facies asymmetry between the downdrift and the updrift sides. The downdrift, sourced primarily by the feeding river, are commonly influenced by mixed river and wave processes. Deposits on this side are muddy and consist of barrier, bar, lagoon, bay-fill, and bayhead delta facies with variable bioturbation intensity. At or near the river mouth, heterolithic river-dominated successions are more typical. Deposits are overall unburrowed （BI 0-2）, but with high burrowing spikes. Ichnogenera are characterized by horizontal, morphologically simple, and facies-crossing structures. The updrift, in contrast, is sourced by a second sediment source and typically consists of laterally continuous sandy beach and shoreface facies. Bioturbation is overall high （BI 3-6） and ichnogenera are healthy and robust, attributable to the Cruziana and Skolithos lchnofacies. Depending on shoreline trajectory and depositional history, facies characteristics of asymmetric deltas preserved in the ancient record, however, can be different from those predicted by the models. Degree of asymmetry is indicated by the asymmetry index （A）, defined as the ratio between the rate of longshore transport at the river mouth and river water discharge. The indexes in symmetric waveinfluenced deltas is less than 200, whereas those in asymmetric and deflected deltas are larger than 200. Overall the larger the index, the higher the degree of asymmetry. Delta asymmetry concepts and models challenge the traditional definition of deltas and the delta classification scheme, in a hydrocarbon exploration perspective, asymmetric deltas bear very different types of sands and, thus, reservoirs between the updrift and the downdrift. The updrift consists of wellsorted, mature, and laterally continuous homogeneous beach-shoreface reservoirs

关键词： Delta asymmetry asymmetry index longshore drift wave-influenced deltas ichnology

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