Subtractive Clustering-Based K-means Technique for Determining Optimum Time-of-Day Breakpoints

In many countries, the most widely used method for timing plan selection and implementation is the time-of-day (TOD) method. In TOD mode, a few traffic patterns that exist in the historical volume data are recognized and used to find the signal timing plans needed to achieve optimum performance of the intersections during the day. Traffic engineers usually determine TOD breakpoints by analyzing 1 or 2?days worth of traffic data and relying on their engineering judgment. The current statistical methods, such as hierarchical and K-means clustering methods, determine TOD breakpoints but introduce a large number of transitions. This paper proposes adopting the Z-score of the traffic flow and time variable in the K-means clustering to reduce the number of transitions. The numbers of optimum breakpoints are chosen based on a microscopic simulation model considering a set of performance measures. By using simulation and the K-means algorithm, it was found that five clusters are the optimum for a major arterial in Al-Khobar, Saudi Arabia. As an alternative to the simulation-based approach, a subtractive algorithm-based K-means technique is introduced to determine the optimum number of TODs. Through simulation, it was found that both approaches results in almost the same values of measure of effectiveness (MOE). The proposed two approaches seem promising for similar studies in other regions, and both of them can be extended for different types of roads. The paper also suggests a procedure for considering the cyclic nature of the daily traffic in the clustering effort.     

ANTEK9000硫氮分析仪在润滑油分析中的应用

介绍了美国ANTEK9000硫氮分析仪的测定原理,说明了该系统对润滑油基础油及其生产原料中硫氮含量的测定,建立了不同硫氮含量的分析模式,阐述了采用该硫氮系统测定润滑油基础油及其生产原料中硫氮含量的适用性和可靠性,提出了仪器的维护、保养和正确的操作方法建议。     

心肌断层显像采集和处理中的若干影响因素分析

总结了６年来我院应用ＳＯＰＨＹＤＳ７型ＳＰＥＣＴ行心肌断层显像５５００余例的临床工作经验，分析了在图像采集过程中开始采集时间，断层体位及在图像处理中本底扣除，心肌以外放射性的干扰等因素对图像质量的影响，提出了如何避免和克服这些因素的建议。     

XKAr-6-1型提氩装置产量质量影响因素分析

分析影响提氩装置产量质量的主要因素为：主塔工况稳定性、粗氩纯度、吸附器使用周期等，针对这些因素提出优化操作要点，使氩气产量质量超过设计水平。     

Polycyclic aromatic hydrocarbons, elemental and organic carbon emissions from tire-wear

Tire-wear is an important source of PAHs, elemental carbon (EC) and organic carbon (OC). The emissions of these pollutants have been studied in an experimental set-up, simulating a realistic road-tire interaction (summer tire-concrete road). The large particle non-exhaust emissions (LPNE; diameter greater than 10 μm) have been evaluated over 14,500 km run of the tire. An increasing linear trend with cumulative km run was observed for emissions of PAHs and carbon. Amongst PAHs in LPNE, pyrene has been observed to be the highest (30 ± 4 mg kg^− 1) followed by benzo[ghi]perylene (17 ± 2 mg kg^− 1). Different fractions of EC-OC for tire-wear have been analyzed, and unlike exhaust emissions, EC1 was observed to be 99% of EC whereas more than 70% of the OC was the high temperature carbon (OC3 and OC4). The overall emission factors (mass tire^− 1 km^− 1) for PAHs, EC and OC from tire-wear are 378 ng tire^− 1 km^− 1, 1.46 mg tire^− 1 km^− 1 and 2.37 mg tire^− 1 km^− 1 for small cars.     

辽宁省种植冬麦的农业气候指标研究

本文通过对可能影响冬麦生育过程的若干因子的分析，筛选出４个主要气候因子，作为辽宁省种植冬麦的农业气候指标。这４个农业气候指标是：越冬前活动积温为４２０～５４０℃，越冬前降水１２０～１７０ｍｍ，抽穗到成熟期降水 １１０～ １５０ｍｍ，越冬期可耐一 ８００ ℃负积温及一２４～一２６℃的极端最低气温。由此，以农业气候相似论为依据，可以实现以沈阳为中心的辽宁省部分地区冬麦北移种植的构想。     

阿北安山岩油藏储层分布发育规律及影响因素

本文借助于岩心观察，野外地质调查，电测曲线，岩心分析化验，试油试采等大量动静态资料，在储层特征、储层及产层分布发育规律等研究的基础上，分析了影响安山岩储层发育的主要因素，深入研究了影响单井产能的主、客观因素，得出对单井产能有较大影响的定量参数有储层厚度、物性参数及上覆地层腾一段厚度等，并就其与单井产能的定量关系进行了研究，将这一关系应用于生产中，指导油田的扩边挖潜及开发调整等工作，收到良好的开发效     

CDCM机组影响带钢表面清洁度的因素分析

指出我国第一条酸洗－轧机联合机组（ＣＤＣＭ机组）带钢表面不洁带来的不良影响；进而对影响带钢板面清洁度的因素（原料、工艺、设备等）进行了分析并提出了相应的解决办法。     

Progression into and out of binge drinking among high school students.

The current study examined binge drinking among high school students over an academic year. Adolescent drinkers (N?=?621; 58% female) were grouped into 4 trajectories: drinkers (35%), increasers (14%), decreasers (16%), and persistent binge drinkers (35%). Prospective analyses indicated several factors that predicted escalation and de-escalation of binge drinking. Increasers were more likely to regularly use alcohol and cigarettes at a younger age than drinkers. Compared with decreasers, persistent binge drinkers reported regular alcohol and marijuana use at younger ages. Lower levels of perceived student drinking appeared to be a protective factor for onset of binge drinking. The results highlight the need to study precursors to the naturally occurring fluctuations in binge drinking and suggest factors that may accentuate the risk of binge drinking. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Principles of engineering safety: Risk and uncertainty reduction

This article provides a systematised account of safety engineering practices that clarifies their relation to the goal of safety engineering, namely to increase safety. We list 24 principles referred to in the literature of safety engineering, dividing them into four major categories: Inherently safe design, Safety reserves, Safe fail and Procedural safeguards. It emerges from this systematisation that important aspects of these methods can be better understood with the help of the distinction between risk and uncertainty.