基于自然驾驶数据的驾驶员变道特征分析

为研究驾驶员的变道特征,包括变道频率、变道动机、注视行为以及转向灯使用情况,基于上海自然驾驶实验采集的驾驶员行为以及车辆运行数据,通过车道偏移值对变道事件进行识别,提取特征变量。对比分析不同类型道路上驾驶员的变道特征,得到以下结论:驾驶员变道较为频繁,城市主干道上变道频率最高,为0.82次/km;高速公路上多车道变道的比例相对较高,安全隐患较大;与美国学者Olsen等人的研究结果相比,驾驶员在变道前查看侧视镜与开启转向灯的比例较高,但极少转头检查盲区。频繁变道、多车道变道以及忽视盲区都是变道过程中存在的安全隐患,深入了解这些特征,从而有针对性地提出改善措施对提高行车安全性有重要意义。

The principle of stability control of surrounding rock-bearing structures in high stress soft rock roadways

Through the description of the deformational features of the surrounding rockaround high stress engineering soft rock roadways,the coupling stabilization principle ofinner and outer structures in surrounding rock was put forward.The supporting principlesof high stress engineering soft rock roadway (high resistance and yielding support,timelysupport,high strength and high stiffness supports) were proposed,which were applied inengineering practices,and obtained better achievements.

Physical modeling of failure process of the excavation in horizontal strata based on IR thermography

In order to capture the mechanism of roadway instability in deep mines, a new approach of Physically Finite Elemental Slab Assemblage (PFESA) is proposed in order to construct a large-scale physical model simulating the geologically horizontal strata. We carried out physical modeling on the deformation and failure processes of roadways subjected to a plane loading scheme. Our laboratory tests were based on work which incorporated infrared (IR) detection, IR radiation temperature (IRT) statistics, image feature extraction and 2D Fourier transformation, from resulting thermographies. The IRT characterizes the mechanical responses from the roadway after loading with two stages, i.e., IRT evolving at higher levels corresponded to shallow mining (≤500 m) during which the roadway deformed gradually (referred to as the "steady deformation stage"); IRT evolving in a quasi-cyclical manner with multiple peaks corresponded to deep mining (800–2600 m), in which the failure mode for the roadway are dominated by breakage and collapse (called the "unsteady deformation stage"). The IR images and 2D Fourier spectra illustrate detailed information in terms of initiation, nucleation and coalescence of the damage to rock masses and the eventual failure of roadways subject to external loading.

Clinicopathological features of minute pharyngeal lesions diagnosed by narrow-band imaging endoscopy and biopsy

AIM:To evaluate the utility of magnified narrow-band imaging(NBI) endoscopy for diagnosing and treating minute pharyngeal neoplasia.METHODS:Magnified NBI gastrointestinal examinations were performed by the first author.A magnification hood was attached to the tip of the endoscope for quick focusing.Most of the examinations were performed under sedation.Magnified NBI examinations were performed for all of the pharyngeal lesions that had noticeable brownish areas under unmagnified NBI observation,and an intrapapillary capillary loop(IPCL) classification was made.A total of 93 consecutive pharyngeal lesions were diagnosed as IPCL type Ⅳ and were suspected to represent dysplasia.Sixty-two lesions of approximately 1 mm in diameter were biopsied in the clinic,and 17 lesions with larger diameters were resected by endoscopic submucosal dissection(ESD) at the Hiroshima University Hospital.In addition to the histological diagnoses,the lesion diameters were microscopically measured in 45 of the 62 biopsies.Thirtyfour of the 62 biopsied patients received endoscopic follow up.RESULTS:Minute pharyngeal lesions were diagnosed in 93 of approximately 3000 patients receiving magnified NBI examinations at the clinic.Of the 93 patients with IPCL type Ⅳ lesions,80 were men,and 13 were women.Fifty-six were drinkers,and 57 were smokers.Two had esophageal cancer.Twenty-one lesions were located on the posterior hypopharyngeal wall,and 72 lesions were located on the posterior oropharyngeal wall.All 93 lesions were flat and showed similar findings in the magnified and unmagnified NBI examinations.Although almost all of the IPCL type Ⅳ lesions showed faint redness when examined under white light,it was difficult to diagnose the lesions using only this technique because the contrast was weaker than that achieved in the NBI examinations.Of the 93 lesions,only 3 had diameters greater than 2.1 mm.Sixty-two lesions of approximately 1 mm were biopsied in the clinic,whereas 17 larger lesions were treated by ESD at the Hiroshima University Hospital.Of the 79 pharyngeal lesions that were biopsied or resected by ESD,5 were histologically diagnosed as high-grade dysplasia,39 were diagnosed as low-grade dysplasia,and 39 were determined to be non-dysplastic lesions.There were no cancerous lesions.Histologically,abnormal cell size variations and increased nuclear size were observed in all of the high-grade dysplasia lesions,while the incidence of these findings in the low-grade dysplasia lesions was low.Of the 62 biopsied lesions,45 were microscopically measurable.The measured diameters ranged from 0.1 to 2.0 mm.The dysplasia ratios increased with the diameters.A follow-up endoscopic examination of the 34 biopsied patients found the rate of complete resection by biopsy to be 79%.The largest lesion in which complete resection was expected was a low-grade dysplasia of 1.9 mm in diameter.CONCLUSION:Minute pharyngeal lesions suspected to be dysplasia that are identified by NBI magnifying endoscopy should be biopsied to determine the diagnosis and further treatment.

Deformation characteristics of surrounding rock of broken and soft rock roadway

A similar material model and a numerical simulation were constructed and are described herein. The deformation and failure of surrounding rock of broken and soft roadway are studied by using these models. The deformation of the roof and floor, the relative deformation of the two sides and the deformation of the deep surrounding rock are predicted using the model. Measurements in a working mine are compared to the results of the models. The results show that the surrounding rock shows clear theological features under high stress conditions. Deformation is unequally distributed across the whole section. The surrounding rock exhibited three deformation stages： displacement caused by stress concentration, theological displacement after the digging effects had stabilized and displacement caused by supporting pressure of the roadway. Floor heave was serious, accounting for 65% of the total deformation of the roof and floor. Floor heave is the main reason for failure of the surrounding rock. The reasons for deformation of the surrounding rock are discussed based on the similar material and numerical simulations.

Clinical Characters of Gastrointestinal Lesions in Intestinal Behcet's Disease

Objective To investigate the clinical features,diagnosis methods,therapeutic principles of intestinal Behcet's disease.Methods The clinical data of 45 patients with confirmed intestinal Behcet's disease admitted to Peking Union Medical College Hospital from August 1998 to April 2010 were retrospectively analyzed.Results The clinical courses of patients with intestinal Behcet's disease were from 26 days to 33 years,and the average duration was 6.32±1.01 years.The appearance of extra-gastrointestinal symptoms was significantly earlier than that of gastrointestinal symptoms(7.35±1.39 years vs.3.24±0.82 years,P<0.05).The predominant gastrointestinal manifestations were right lower quadrant pain(95.56%) and hematochezia or melena(40.00%).Misdiagnosis occurred in 17 cases.In patients without systemic medicine therapy before surgery,the incidence of postoperative infection of incision site and abdominal cavity was significantly higher than that in those undergoing systemic medicine therapy(80.00% vs.0%,P<0.05).Conclusions Because of the diversity of gastrointestinal manifestations,intestinal Behcet's disease is easily misdiagnosed.The systemic medical therapy before surgery could decrease the incidence of infection of incision and abdominal cavity.