相邻车道车辆并道预测与跟车控制改进的研究

为在自适应跟车控制中,预测相邻车道车辆的并道行为,提前调整自车速度控制策略,以提高自车的乘坐舒适性和安全性,通过采集和分析实际道路上自车与周围车辆的运动状态信息,建立相邻车道车辆并道行为预测模型,并在此基础上对现有期望间距跟车模型进行改进。仿真结果表明:自车车速vM、自车与前车的车头时距t1、自车与前车的相对速度vML和自车与相邻车道车辆的相对速度vMF可作为预测并道行为的表征参数;所建立的预测模型可提前2s预测并道行为的类型,对两种并道行为预测的准确率分别达到88%和90%;改进的期望间距模型使跟车过程更加平稳,可提高车辆的舒适性与安全性。

“王霸并道”思想及其管理智慧

探讨荀子与管子“王霸并道”思想在理论上的可取之处,指出自汉以降的中国历史就是一部“王霸并道”的政治统治史;同时探讨了研究“王霸并道”思想的现实意义。“王霸并道”思想对国家权威的建立与维护、国家国际战略的选择以及对提高企业的战略管理水平都具有重要的借鉴意义。

智能车辆并道行为轨迹规划及跟踪控制

针对智能车辆并道行为中存在的问题,提出了一种轨迹规划与跟踪控制算法。首先,提出了一种基于五次多项式的并道轨迹,以乘车人的安全性,舒适性及并道效率建立目标函数来求解最优并道参考轨迹;其次,根据智能车辆并道过程中横摆角的变化关系,提出了一种自适应MPC控制器,提高了车辆并道道路径跟踪控制性能。仿真结果表明提出的算法能够实现智能车辆的并道行为,同时具有稳定性,安全性。

TD3算法改进与自动驾驶汽车并道策略学习

为提高自动并道策略的综合性能,改进了双延迟深度确定性策略梯度算法(Twin delayed deep deterministic policy gradient,TD3)的Q值估计方法和奖励函数。通过马尔科夫决策过程,将车辆并道过程建模为强化学习问题,分析TD3强化学习算法中Q值低估对并道决策的影响。对TD3算法的双评论家目标网络执行蒙特卡洛随机失活,在获得两个Q值估计样本的基础上,提出基于样本方差加权平均的Q值估计方法,提高TD3算法的Q值估计精度。在优先保证完成并道任务的前提下,充分考虑车辆并道过程中的安全性、舒适性和交通效率,建立完备的奖励函数。基于改进的TD3算法和奖励函数,通过BARK模拟器开展自动驾驶汽车并道策略学习和测试。结果表明,提出的改进TD3算法显著提高了Q值估计精度。结合建立的奖励函数,在保证交通效率的同时提高了车辆并道的安全性和乘坐舒适性。

并道运行状态下高速公路桥梁车辆荷载效应

为得到并道运行状态下车辆荷载对桥梁结构的作用效应,利用1座连续梁桥的实测车辆荷载数据,研究了并道运行状态下高速公路桥梁的车辆荷载效应分析方法。首先,根据车辆并道的特点,通过EM算法得到了车重、轴重、轴间距和车间距等参数的分布特征;然后,针对并道运行状态下车间距减小和拥堵的2种情况,提出了相应随机车辆荷载流的模拟方法;最后,结合随机车辆荷载影响线和极值分布理论,计算得到了并道运行状态桥梁车辆荷载效应的评估值,并分析了车间距对车辆荷载效应的影响规律。研究结果表明:并道运行状态下车重、轴重、轴间距服从混合Gauss分布,车间距服从对数正态分布;针对并道运行状态随机车辆荷载的模拟方法可以较好地分析该状态下高速公路桥梁的车辆荷载效应,其中车辆并道状态下所研究桥梁的荷载效应评估值分别为汽车超-20、公路Ⅰ级的1.13、1.03倍;当车辆并道且发生拥堵的最不利状态时,荷载效应分别为设计荷载汽车超-20、公路Ⅰ级的1.29、1.17倍;车辆并道受车间距的影响较大,车间距在2~5m时车辆间距内的效应值与车辆间距的大小基本呈线性关系,当车辆间距控制在10m以上时,可确保该桥实际车辆荷载效应小于设计荷载效应。研究结果可为并道运行状态桥梁承载能力评估和并道运行的交通布控提供参考。

基于DSP系统的多道脉冲幅度分析器设计

介绍了一种基于DSP系统的高性能、低功耗多道脉冲幅度分析器的软硬件设计。硬件设计从提高多道脉冲幅度分析器的数据处理能力和降低系统功耗的角度出发重点介绍了能处理小信号的峰保电路、高速高精度的模数转换电路以及DSP系统及其相关外设接口;软件设计介绍了基于DSP系统的软件模块和基于CPLD的软件编程。还给出了该系统在XR-100CR探测器上测得的Fe的能谱示例。

霍贝玛的《并道树》 宁静的灵魂享受之地

这是一幅描绘乡间风情的作品，它给人展现出一种平远透视美：两边成行的树枝对称、且错落有致，近景的深色树丛与种植林疏密相间，在远处，左旁有一座教堂的尖顶，右旁是两幢高顶茅舍，它让观看者有一种极目远望、清澈的感觉，灵魂似乎也随之而安宁。这就是霍贝玛的《并道树》。

高速路相邻前车驾驶人意图预测

针对相邻车道前车并道至自车与本道前车之间会使自车的跟车间距突然减小,进行高速公路实车试验,采集自车、自车所在车道以及相邻车道车辆的运动状态参数,基于SVM算法和Fisher判别法对高速公路相邻前车的驾驶人意图进行预测。结果表明,自车车速、自车与当前车道前车的车头时距、纵向相对速度以及自车与相邻前车的纵向相对速度可以作为相邻前车驾驶意图的表征参数,所建立的驾驶意图预测模型能够提前2 s预测驾驶人的意图,且SVM模型和Fisher模型的驾驶意图预测准确率分别为94.1%和91.1%,该模型能够为自适应跟车控制提供一定的理论指导。

驾驶模拟在公路安全设计与运行中运用的研究

随着日益增长的交通需求,为了能够获得最高性能的公路交通系统,驾驶任务变得越来越复杂,公路设计和建设中考虑人的因素也变得更为重要。能否成功引进新的驾驶支持体系、动态的交通管理系统或者复杂的道路设计,主要依赖于人们是否能够以及有多大意愿去适应这种发展。为此需要了解人们在复杂的动态驾驶任务环境中将会做出怎样的反应。该文在简单地介绍完TNO驾驶模拟器设备后,又介绍了有关利用先进的人机互动驾驶模拟器研究人的驾驶行为来进行公路设计和建设。文中通过几个公路设计和交通运输行为研究的例子,说明了驾驶模拟器研究对安全有效地进行公路设计与运行运用具有特殊的价值。

Spatial channel pairing-based maximum ratio combining algorithm for cooperative relay networks

To improve the reliable performance of information transmission in cooperative relay networks, the scheme of the max-rate spatial channel pairing （SCP） based on maximum ratio combining （MRC） is proposed. The scheme includes three steps： channel phase cancellation, MRC, and SCP. Eventually, the solution of the scheme is modeled as convex optimization. The objective function of the optimization problem is to maximize the transmission rate and the optimization variable is the strategy of pairing between the uplink spatial sub-channels of each user and the corresponding downlink spatial ones. The theorem of the arrangement inequalities is adopted to obtain the approximate closed-form solution of the optimal pairing for this convex optimization. Simulation results demonstrate that compared to the existing distributed space-time block coding and coherent combined schemes without SCP, the proposed max-rate SCP plus MRC algorithm achieves appreciable improvements in symbol error rate in medium and high signal-to-noise ratio regimes. The achievable performance gain is due to the use of maxrate SCP.

Lower bound on BER performance for maximal ratio combining with weighting errors

The theoretical lower bounds on mean squared channel estimation errors for typical fading channels are presented by the infinite-length and non-causal Wiener filter and the exact closed-form expressions of the lower bounds for different channel Doppler spectra are derived. Based on the obtained lower bounds on mean squared channel estimation errors, the limits on bit error rate （BER） for maximal ratio combining （MRC） with Gaussian distributed weighting errors on independent and identically distributed （i. i. d） fading channels are presented. Numerical results show that the BER performances of ideal MRC are the lower bounds on the BER performances of non-ideal MRC and deteriorate as the maximum Doppler frequency increases or the SNR of channel estimate decreases.

High Speed VCSEL-Based Parallel Optical Transmission Modules

Design and fabrication of a parallel optical transmitter are reported. The optimized 12 channel parallel optical transmitter,with each channel＇s data rate up to 3Gbit/s,is designed, assembled, and measured. A top-emitting 850nm vertical cavity surface emitting laser（VCSEL） array is adopted as the light source,and the VCSEL chip is directly wire bonded to a 12 channel driver IC. The outputs of the VCSEL array are directly butt coupled into a 12 channel fiber array. Small form factor pluggable （SFP） packaging technology is used in the module to support hot pluggable in application. The performance results of the module are demonstrated. At an operating current of 8mA, an eye diagram at 3Gbit/s is achieved with an optical output of more than 1mW.

Education-based approach to addressing non-evidence-based practice in preventing NSAID-associated gastrointestinal complications

AIM:To evaluate an evidence-based educational program for improving strategies for prevention of non-steroidal anti-inflammatory drug(NSAID)-associated gastrointestinal(GI)complications. METHODS:Four hundred and fifty-six specialists replied to a questionnaire that covered issues related to NSAID-induced adverse effects.They also collected data from their last five consecutive patients before and after they had attended an evidence-based seminar on GI prevention strategies. RESULTS:Four hundred and forty-one of 456 specialists(96.7%)participated in the survey,and 382(83.7%)in the education-based study that recorded data from 3728 patients.The specialists overestimated the risk of GI complications with NSAIDs,underestimated the GI safety profile of coxibs,but were aware of the risk factors and of the current prevention strategies.Proton pump inhibitors were co-prescribed with NSAIDs in>80% of patients with and without risk factors.The educational program had little impact on prescribing habits.CONCLUSION:Specialists are informed of advances in NSAID-associated adverse effects and have high rates of GI-prevention therapy.Our educational program did not alter these rates.

Urethral complications after tension-free vaginal tape procedures:A surgical management case series

AIM： To analyze the clinical features, diagnostic modalities, and the surgical management of urethral complications after tension-free vaginal tape procedures.METHODS： This study encompasses a retrospective review of nine patients presented with urethral complic-ations after midurethral sling procedures. The patients underwent the procedures during a period from 1999 to 2012 in three different regional hospitals in the southwest part of Sweden. The time from sling placement to diagnosis, the risk factors, clinical features, diagnosis, surgical management, and functional outcome are presented. The presenting symptoms were described as either early onset （〈 12 mo） or late onset （〉 12 mo） according to when they were frst reported.RESulTS： Eight cases of urethral erosion and one case of bladder-neck erosion were detected. The mean interval for diagnoses of the erosions ranged from 3 mo to 11 years. The most common presenting symptoms included de novo urgency with or without incontinence （7/9 patients）, urinary retention/voiding dysfunction （4/9 patients）, urethritis （4/9 patients）, relapse of stress-incontinence （3/9 patients）, recurrent urinary tract infections （5/9 patients）, and hematuria （1/9 patient）. In most cases, voiding dysfunction and urethritis occurred early after the operation. The surgical management applied in most cases was transurethral resection of the intraurethral part of the mesh. The removal of the intraurethral mesh resulted in improvement or complete cure of urgency symptoms in 5/7 patients with urgency. Four patients were reoperated with a new stress-incontinence surgery, one with laparoscopic Burch, and three with retropubic tension-free vaginal tape procedures. COnCluSIOn： Urethral complications should be suspected in the case of de novo urgency and relapse of stress-incontinence. Transurethral excision of the intraurethral mesh is the recommended treatment.

Percutaneous liver biopsy complicated by hemobilia-associated acute cholecystitis

Liver biopsy is generally considered a safe and highly useful procedure. It is frequently performed in an outpatient setting for diagnosis and follow-up in numerous liver disorders. Since its introduction at the end of the 19th century, broad experience, new imaging techniques and special needles have significantly reduced the rate of complications associated with liver biopsy. Known complications of percutaneous biopsy of the liver include hemoperitoneum, subcapsular hematoma, hypotension, pneumothorax and sepsis. Other intra-abdominal complications are less common. Hemobilia due to arterio-biliary duct fistula has been described, which has only rarely been clinically expressed as cholecystitis or pancreatitis. We report a case of a fifteen year-old boy who developed severe acute cholecystitis twelve days after a percutaneous liver biopsy performed in an outpatient setting. The etiology was clearly demonstrated to be hemobilia-associated, and the clinical course required the performance of a laparoscopic cholecystectomy. The post operative course was uneventful and the patient was discharged home. Percutaneous liver biopsy is a safe and commonly performed procedure. However, severe complications can occasionally occur. Both medical and surgical options should be evaluated while dealing with these rare incidents.

Comorbidity in inflammatory bowel disease

Patients with inflammatory bowel disease (IBD) can be affected by other unrelated diseases. These are called comorbid conditions, and can include any secondary health problem that affects a person suffering from a primary or main disease, and which is neither linked physiopathologically to the primary condition, nor is it due to the treatments used for the primary condition or to its long-term anatomical or physiological consequences. Different comorbid conditions, as well as their influence on IBD, are discussed.

The Bipolar Field-Effect Transistor:Ⅰ.Electrochemical Current Theory(Two-MOS-Gates on Pure-Base)

This paper describes the bipolar field-effect transistor （BiFET） and its theory. Analytical solution is ob- tained from partitioning the two-dimensional transistor into two one-dimensional transistors. The analysis employs the parametric surface-electric-potential and the electrochemical （quasi-Fermi） potential-gradient driving force to compute the current. Output and transfer D. C. current and conductance versus voltage are presented over practi- cal ranges of terminal D. C. voltages and device parameters. Electron and hole surface channel currents are pres- ent simultaneously, a new feature which could provide circuit functions in one physical transistor such as the CMOS inverter and SRAM memory.

Does testosterone prevent early postoperative complications after gastrointestinal surgery?

AIM:To investigate the role of sex hormones in the early postoperative complications of gastrointestinal diseases. METHODS:A total of 65 patients who underwent operations for gastric and colorectal diseases(mainly malignant diseases)were included in the study. Peripheral venous blood samples were collected at different times for analysis of estradiol,testosterone and progesterone.The only study endpoint was analysis of postoperative complications. RESULTS:Patients of both sexes were uniform but postoperative complication rate was significantly higher in female patients(P=0.027).There was no significant association of estradiol and progesterone with postoperative complications.Testosterone levels in complicated patients were significantly lower than in uncomplicated patients(P<0.05).Area under the receiver operating characteristic curve showed that a lower value of testosterone was a predictor for higher complication rate(P<0.05),and a lower value oftestosterone at later times after surgery was a better predictor of complications. CONCLUSION:Patients with low testosterone level were prone to higher postoperative complications,which was evident in both sexes.However,further studies are necessary to support this result.

A case report of abdominal distention caused by herpes zoster

Gastrointestinal complications caused by herpes zoster are extremely rare. Here, we described a case of abdominal distention caused by herpes zoster. The patient was a 59-year-old female who suffered from unexplained paroxysmal and a burning pain on the right part of her waist and abdomen, accompanied by abdominal distention. Intestinal pseudo-obstruction was diagnosed by abdominal radiography. Distention of the right abdominal wall was still apparent after one month. In this report, we found that recovery from abdominal distention caused by herpes zoster is difficult and may require surgical intervention.

Factors associated with complicated erosive esophagitis: A Japanese multicenter, prospective, cross-sectional study

AIMTo assess the clinical characteristics of patients with complicated erosive esophagitis (EE) and their associated factors.METHODSThis prospective, cross-sectional study included patients diagnosed with EE by upper gastrointestinal endoscopy between October 2014 and March 2015 at 106 Japanese hospitals. Data on medical history, general condition, gastrointestinal symptoms, lifestyle habits, comorbidities, and endoscopic findings were collected using a standard form to create a dedicated database. Logistic regression analysis was used to calculate adjusted odds ratios (aOR) and 95%CI for the association with complicated EE.RESULTSDuring the study period, 1749 patients diagnosed with EE, 38.3% of whom were prescribed proton pump inhibitors (PPIs) were included. Of them, 143 (8.2%) had EE complications. Esophageal bleeding occurred in 84 (4.8%) patients, esophageal strictures in 45 (2.6%) patients, and 14 (0.8%) patients experienced both. Multivariate analysis showed that increased age (aOR: 1.05; 95%CI: 1.03-1.08), concomitant use of psychotropic agents (aOR: 6.51; 95%CI: 3.01-13.61), and Los Angeles grades B (aOR: 2.69; 95%CI: 1.48-4.96), C (aOR: 15.38; 95%CI: 8.62-28.37), and D (aOR: 71.49; 95%CI: 37.47-142.01) were significantly associated with complications, whereas alcohol consumption 2-4 d/wk was negatively associated (aOR: 0.23; 95%CI: 0.06-0.61). Analyzing associated factors with each EE complication separately showed esophageal ulcer bleeding were associated with increased age (aOR: 1.05; 95%CI: 1.02-1.07) and Los Angeles grades B (aOR: 3.60; 95%CI: 1.52-8.50), C (aOR: 27.61; 95%CI: 12.34-61.80), and D (aOR: 119.09; 95%CI: 51.15-277.29), while esophageal strictures were associated with increased age (aOR: 1.07; 95%CI: 1.04-1.10), gastroesophageal reflux symptom (aOR: 2.51; 95%CI: 1.39-4.51), concomitant use of psychotropic agents (aOR: 11.79; 95%CI: 5.06-27.48), Los Angeles grades C (aOR: 7.35; 95%CI: 3.32-16.25), and D (aOR: 20.34; 95%CI: 8.36-49.53) and long-segment Barrett&#x02019;s esophagus (aOR: 4.63; 95%CI: 1.64-13.05).CONCLUSIONAging and severe EE were common associated factors, although there were more associated factors in esophageal strictures than esophageal ulcer bleeding. Despite the availability and widespread use of PPIs, EE complications are likely to remain a problem in Japan owing to the aging population and high-stress society.