一种基于stop-and-go改进的MCMA盲均衡算法

修正的常数模算法(MCMA)可以纠正相位旋转,但剩余稳态误差较大.在stop-and-go架构的基础上,提出了基于stop-and-go改进的MCMA算法.首先将局部信息量引入MCMA的误差函数,然后运用stop-and-go减少错误均衡的思想,使算法的均衡方向与MCMA保持一致,以降低剩余稳态误差.仿真结果表明,基于stop-and-go改进的MCMA盲均衡算法在保证了收敛速度的同时,码间干扰比MCMA算法降低了10dB.

Multicenter Analysis of mFOLFOX6 with Oxaliplatin Stop-and-Go Strategy Using Oral Uracil-Tegafur with Leucovorin for Unresectable Colorectal Cancer in Elderly Patients

Background: This study evaluated the tolerability and efficacy of intermittent oxaliplatin treatment based on mFOLFOX6 using oral uracil-tegafur(UFT) and leucovorin(LV) maintenance therapy in the treatment of elderly patients with advanced colorectal cancer. Methods: Ten non-elderly patients (70 years) with advanced/recurrent colorectal cancer were enrolled in this prospective, multicenter cooperative group clinical trial. The mFOLFOX6 regimen was administered for eight cycles with maintenance therapy with oral UFT/LV treatment until progression. In cases with disease progression, mFOLFOX6 was reintroduced. Results: Grade 2 peripheral neuropathy was noted in 30.0% and 25.0% of the elderly and non-elderly patients, respectively. The observed time to treatment failure (TTF) was 6.3 months in the elderly patients and 6.4 months in the non-elderly patients. The disease control rate was 83.3% in each group. Conclusion: Our new stop-and-go strategy using oral UFT/LV is well-tolerated and effective even in elderly patients.

Stop-and-go waves induced by correlated noise in pedestrian models without inertia

Stop-and-go waves are commonly observed in traffic and pedestrian flows.In most microscopic traffic models,they occur through a phase transition and instability of the homogeneous solution after fine tuning of parameters.Inertia effects are believed to play an important role in this mechanism.In this article,we present a novel explanation for stop-and-go waves based on stochastic effects in the absence of inertia.The model used is a first order optimal velocity(OV)model including an additive stochastic noise.A power spectral analysis for single-file pedestrian trajectories highlights the existence of Brownian speed residuals.We use the Ornstein-Uhlenbeck process to describe such a correlated noise.The introduction of this specific colored noise in the first order OV model allows describing realistic stop-and-go behavior without requiring instabilities or phase transitions,the homogeneous configurations being systematically stochastically stable.We compare the stochastic model to deterministic unstable OV models and analyze individual speed autocorrelation to describe the nature of the waves in stationary states.We apply the approach to pedestrian single-file motion and compare simulation results to real pedestrian trajectories.The simulation results are quantitatively very similar to the real trajectories.We discuss plausible values for the model parameters and their meaning.

一种适用于GEO SAR远地点的改进SRC算法

针对地球同步轨道合成孔径雷达在远地点采用原有的等效直线模型速度和斜视角会出现复数,以及"Stop-and-Go"假设不成立的问题,进行了二次距离压缩算法(SRC)的改进,提出了一种新的信号模型,修正了成像算法中的补偿函数,而且采用高阶近似的方法得到了精确的方位向调频率,改进了方位向压缩函数.结果表明改进的二次距离压缩算法可以在合成孔径时间100s内聚焦远地点40km×40km的场景,且场景边缘点的峰值旁瓣比和积分旁瓣比与理论值非常接近.

一种基于子带分解技术的宽带盲均衡器结构和算法

高速宽带无线通信中,多径传输信道可能导致几百个符号间的相互干扰,这使得接收端的线性盲均衡器的收敛速度极其缓慢。基于子带分解技术,该文提出了一种适合于高速宽带无线传输的盲均衡器结构及算法。该结构将子带分解技术和全频带的子卷积方法有机结合在一起,明显地加快了高速宽带传输条件下线性盲均衡器的收敛速度;同时通过对接收数据进行降低速率的并行处理,该结构还能减小运算复杂度,有利于工程的实时实现。仿真实验结果验证了文中提出的结构和算法的有效性。

A New Macro Model for Traffic Flow on a Highway with Ramps and Numerical Tests

In this paper, we present a new macro model for traffic flow on a highway with ramps based on the existing models. We use the new model to study the effects of on-off-ramp on the main road traffic during the morning rush period and the evening rush period. Numerical tests show that, during the two rush periods, these effects are often different and related to the status of the main road traffic. If the main road traffic flow is uniform, then ramps always produce stop-and-go traffic when the main road density is between two critical values, and ramps have little effect on the main road traffic when the main road density is less than the smaller critical value or greater than the larger critical value. If a small perturbation appears on the main road, ramp may lead to stop-and-go traffic, or relieve or even eliminate the stop-and-go traffic, under different circumstances. These results are consistent with real traffic, which shows that the new model is reasonable.

Kinetic description of bottleneck effects in traffc flow

This paper deals with the effects of traffic bottlenecks using an extended Lighthill-Whitham-Richards （LWR） model. The solution structure is analytically indicated by the study of the Riemann problem characterized by a discontinuous flux. This leads to a typical solution describing a queue upstream of the bottleneck and its width and height, and informs the design of a δ-mapping algorithm. More significantly, it is found that the kinetic model is able to reproduce stop-and-go waves for a triangular fun-damental diagram. Some simulation examples, which are in agreement with the analytical solutions, are given to support these conclusions.

Influence of bottleneck on single-file pedestrian flow:Findings from two experiments

In order to investigate the influence of bottleneck on single-file pedestrian flow,we conduct two different bottleneck experiments.The first one is on ring road,while the second one is on straight route.For the first one,the global density is always set to be 1.5 ped/m.The corresponding critical flow rate for the bottleneck activation is about 0.57 ped/s.The data of the detectors set at different locations,including the velocities and time-headways,show that the amplitude of the oscillation of the stop-and-go waves gradually increases during the upstream propagation.Besides,when the measured flow rates are the same,the different situations in the single-file experiments with and without bottleneck are compared and discussed.For the second one,lower flow rates are used and the bottleneck is always activated.In all the runs,the system can reach one stable state,and the time needed is nearly the same.Inside the stable area,the statistics of pedestrians'velocities keeps nearly constant in both time and space.Outside this area,when the waiting time is not long(X=10 s),the phenomenon observed is similar to that found on ring road,e.g.,the statistics of pedestrians'velocities also gradually increases during the upstream propagation.This phenomenon is similar to that found in vehicular traffic flow,which shows the universality of different traffic flows.But when the waiting time becomes longer(X=20 s),this situation will be broken since the actions of many pedestrians become much slower.All these results can facilitate understanding more about the influence of bottleneck on single-file pedestrian flow.

Conservation form of Helbing's fluid dynamic traffic flow model

A standard conservation form is derived in this paper.The hyperbolicity of Helbing＇s fluid dynamic traffic flow model is proved,which is essential to the general analytical and numerical study of this model.On the basis of this conservation form,a local discontinuous Galerkin scheme is designed to solve the resulting system efficiently.The evolution of an unstable equilibrium traffic state leading to a stable stop-and-go traveling wave is simulated.This simulation also verifies that the model is truly improved by the introduction of the modified diffusion coefficients,and thus helps to protect vehicles from collisions and avoide the appearance of the extremely large density.

PROBABILITY MODEL OF GUNTHER GENERATOR

This paper constructs the probability model of Gunther generator at first, and the finite dimension union distribution of the output sequence is presented. The result shows that the output sequence is an independent and uniformly distributed 0,1 random variable sequence. It gives the theoretical foundation about why Gunther generator can avoid the statistic weakness of the output sequence of stop-and-go generator, and analyzes the coincidence between output sequence and input sequences of Gunther generator. The conclusions of this paper would offer theoretical references for designers and analyzers of clock-controlled generators.

Longitudinal Acceleration Tracking Control of Low Speed Heavy-Duty Vehicles

This paper presents a model matching control （MMC） method based on the sliding mode control （SMC） method for longitudinal acceleration tracking control in a vehicular stop-and-go cruise control system. The nonlinearity of the vehicle acceleration response at low speeds was analyzed to develop a transfer function model of the vehicle longitudinal dynamics using the least-mean-square system identification technique. This transfer function was then used to design the MMC controller, including an SMC feedback compensator. The system combines the advantages of the two control methods with robust control and rapid response. Simulations show that the controller enhances the rapid trackability to the vehicle acceleration and improves the system＇s robustness at low speeds compared with conventional PID MMC controllers.

Pro-social control of connected automated vehicles in mixed-autonomy multi-lane highway traffic

We propose pro-social control strategies for connected automated vehicles(CAVs)to mitigate jamming waves in mixed-autonomy multi-lane traffic,resulting from car-following dynamics of human-driven vehicles(HDVs).Different from existing studies,which focus mostly on ego vehicle objectives to control CAVs in an individualistic manner,we devise a pro-social control algorithm.The latter takes into account the objectives(i.e.,driving comfort and traffic efficiency)of both the ego vehicle and surrounding HDVs to improve smoothness of the entire observable traffic.Under a model predictive control(MPC)framework that uses acceleration and lane change sequences of CAVs as optimization variables,the problem of individualistic,altruistic,and pro-social control is formulated as a non-convex mixed-integer nonlinear program(MINLP)and relaxed to a convex quadratic program through converting the piece-wise-linear constraints due to the optimal velocity with relative velocity(OVRV)car-following model into linear constraints by introducing slack variables.Low-fidelity simulations using the OVRV model and high-fidelity simulations using PTV VISSIM simulator show that pro-social and altruistic control can provide significant performance gains over individualistic driving in terms of efficiency and comfort on both single-and multi-lane roads.

Simulating bicycle traffic by the intelligent-driver model-Reproducing the traffic-wave characteristics observed in a bicycle-following experiment

Bicycle traffic operations become increasingly important and yet are largely ignored in the traffic flow community,until recently.We hypothesize that there is no qualitative difference between vehicular and bicycle traffic flow dynamics in single-file case,so the latter can be described by reparameterized car-following models.To test this proposition,we reproduce German(Andresen et al.,2014)and Chinese(Jiang et al.,2016)bicycle experiments on a ring with the intelligent-driver model(IDM)and compare its fit quality(calibration)and predictive power(validation)with that of the necessary-deceleration-model(NDM),which is specifically designed for bike traffic.We find similar quality metrics for both models,so the above hypothesis of a qualitative equivalence cannot be rejected.Moreover,calibration errors of the IDM turn up to be slightly smaller compared to the NDM ones.The NDM represents significant calibration errors for high flow densities,which correspond to flow states,when stop-and-go wave emerge.According to validation tests,the IDM outperforms the NDM as well.Performing two types of validation techniques we discover that inter-driver variation is much higher than the intra-driver variation for bicycle traffic.It coincides with the results obtained from vehicular traffic experiments(NGSIM trajectory data).In addition,we suggest the measure for quantitative comparison of two microscopic fundamental diagrams,which are derived from experimental data and simulated trajectories.The analysis of speed-density relations provides more or less the same results for both models.