基于ECP的轨道交通直流牵引供电系统开关状态评价算法

建立1500 V直流开关柜状态评价模型对地铁的安全运行具有重要意义。为此,依据DC1500 V直流开关柜运行原理及其运行过程中体现的指标量,以断路器信息为主,结合配件信息和柜体信息,建立其状态评价指标体系,对直流开关柜功能状态进行综合评价。状态评价算法以熵-突变级数(Entropy-Catastrophe Progression, ECP)法为基础,以信息熵取代主观权重,避免了评价过程中主观因素的干扰,使得设备信息能更直接地影响评价过程,并依据云模型进行指标模糊化,充分考虑了指标量的随机性和模糊性。状态评估模型充分考虑了影响直流开关柜运行状态的各种因素,通过信息熵能客观反映实际情况,并能在指标缺失的情况下给出合理评价。应用开关柜实际运行数据进行实例分析,验证了所提出的状态评价算法的有效性和可行性。     

基于DEM的堰塞湖1／3溃决模拟及人员撤离方案研究

建立了堰塞湖1／3溃决下,洪水的水流速度、淹没区域及到达时间等模型.根据模型,利用DEM(三维数字高程模型)和MATLAB软件模拟了汶川地震唐家山堰塞湖1／3溃决后的洪水演进情况,设计了“人员撤离紧迫性”的量化方法,拟订了下游人员撤离方案,为部队和政府相关部门撤离群众提供了数据支持.最后对模型的精确性进行了评价,针对地震堰塞湖应急评估中存在的数据不足、时效性较差等问题提出了建议.     

Not all breaks are equal: Variable hydrologic and geomorphic responses to intentional levee breaches along the lower Cosumnes River,California

The transport of water and sediment from rivers to adjacent floodplains helps generate complex floodplain, wetland, and riparian ecosystems. However, riverside levees restrict lateral connectivity of water and sediment during flood pulses, making the re‐introduction of floodplain hydrogeomorphic processes through intentional levee breaching and removal an emerging floodplain restoration practice. Repeated topographic observations from levee breach sites along the lower Cosumnes River (USA) indicated that breach architecture influences floodplain and channel hydrogeomorphic processes. Where narrow breaches (<75 m) open onto graded floodplains, archetypal crevasse splays developed along a single dominant flowpath, with floodplain erosion in near‐bank areas and lobate splay deposition in distal floodplain regions. Narrow breaches opening into excavated floodplain channels promoted both transverse advection and turbulent diffusion of sediment into the floodplain channel, facilitating near‐bank deposition and potential breach closure. Wide breaches (>250 m) enabled multiple modes of water and sediment transport onto graded floodplains. Advective sediment transport along multiple flow paths generated overlapping crevasse splays, while turbulent diffusion promoted the formation of lateral levees through large wood and sediment accumulation in near‐bank areas. Channel incision (>2 m) upstream from a wide levee breach suggests that large flow diversions through such breaches can generate water surface drawdown during flooding, resulting in localized flow acceleration and upstream channel incision. Understanding variable hydrogeomorphic responses to levee breach architecture will help restoration managers design breaches that maximize desired floodplain topographic change while also minimizing potential undesirable consequences such as levee breach closure or channel incision.     

On the accuracy of musical data, with examples from Gregorian chant and German folksong

Attention is drawn to the need for controlling (during encoding) and checking (after encoding) the quality or accuracy of musical data. Some large databases of melodies are now becoming available, and methods of control and checking are presented which are specially suited to these. Two applications are discussed in detail: to Gregorian Chant and to German folksong. An effective method in tonal and modal music is found to be the investigation of melodic progressions which remain unusual even after amalgamation by transposition to a central register. Dr. Nigel Nettheim is Senior Research Associate in the Centre for Liberal and General Studies, University of New South Wales, Australia. His research combines Mathematical Statistics and Analytical Musicology. Publications include On the Spectral Analysis of Melody, Interface,21 (1992), and The Pulse in German Folksong: A Statistical Investigation, Musikometrika5, (to appear). The author thanks the anonymous reviewers for helpful remarks.     

Probabilistic prediction models for crack initiation and progression of spray sealed pavements

Cracking is one of the primary distress modes in spray (chip)-sealed pavement surface performance and its prediction is a major concern for pavement engineers. In order to identify, manage and asses effectively and efficiently cracked pavement at a network level, a probabilistic modelling approach is utilised to develop cracking initiation and progression models. This study aims to predict the probability of pavement cracks occurring using a binary logistic model and cracks progression over time using an ordinal logistic regression model. These models have been developed to take into account the effect of variations among observations, among sections and among highways. Readily available historical time series data (from 2004 to 2011) from 40 highway segments have been collected and prepared for modelling. These time series include surface cracking as a performance parameter and traffic loading, expansion potential of subgrade soil, climate condition, condition of drainage system and pavement strength as predictor parameters. Cracking data include all types of cracking: transverse, longitudinal and crocodile cracking and is reported as a percent of the affected area. The study estimates the probability of crack initiation at a certain time and predicts the probability of a pavement maintaining its current level of cracking. It is found that with the 50% estimated probability, about 82% of the observations are correctly predicted by the crack initiation model and 65% of the observations are correctly predicted by the crack progression model. The study has concluded that the effect of time is stronger than the other variables on crack initiation and progression. Also, the effect of traffic loading is stronger than the effect of initial pavement strength in crack initiation phase. However, the effect of pavement strength at any time is stronger than the effect of traffic loading in crack progression phase. The predicted probabilities have been successfully validated using another data-set from the same network and the results indicate that the developed probability models are well estimating the crack conditions and have the ability to predict future conditions accurately.     

正确运用合同法维护企业合法权益

实例说明企业如何在合同的订立、履行及违约责任的追究等方面正确地运用合同法、维护企业合法权益。     

Programmed Death-Ligand 1 as a Regulator of Tumor Progression and Metastasis

Programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) immune checkpoint has long been implicated in modeling antitumor immunity; PD-1/PD-L1 axis inhibitors exert their antitumor effects by relieving PD-L1-mediated suppression on tumor-infiltrating T lymphocytes. However, recent studies have unveiled a distinct, tumor-intrinsic, potential role for PD-L1. In this review, we focus on tumor-intrinsic PD-L1 signaling and delve into preclinical evidence linking PD-L1 protein expression with features of epithelial-to-mesenchymal transition program, cancer stemness and known oncogenic pathways. We further summarize data from studies supporting the prognostic significance of PD-L1 in different tumor types. We show that PD-L1 may indeed have oncogenic potential and act as a regulator of tumor progression and metastasis.     

Proteins that underlie neoplastic progression of ulcerative colitis

Patients with ulcerative colitis (UC) have an increased risk for developing colorectal cancer. Because UC tumorigenesis is associated with genomic field defects that can extend throughout the entire colon, including the non‐dysplastic mucosa, we hypothesized that the same field defects will include abnormally expressed proteins. Here, we applied proteomics to study the protein expression of UC neoplastic progression. The protein profiles of colonic epithelium were compared with (i) UC patients without dysplasia (non‐progressors), (ii) non‐dysplastic colonic tissue from UC patient with high‐grade dysplasia or cancer (progressors), (iii) high‐grade dysplastic tissue from UC progressors, and (iv) normal colon. We identified differential protein expression associated with UC neoplastic progression. Proteins relating to mitochondria, oxidative activity, and calcium‐binding proteins were some of the interesting classes of these proteins. Network analysis discovered that Sp1 and c‐myc proteins may play roles in UC early and late stages of neoplastic progression, respectively. Two over‐expressed proteins in the non‐dysplastic tissue of UC progressors, carbamoyl‐phosphate synthase 1 and S100P, were further confirmed by immunohistochemistry analysis. Our study provides insight into the molecular events associated with UC neoplastic progression, which could be exploited for the development of protein biomarkers in fields of non‐dysplastic mucosa that identify a patient's risk for UC dysplasia.