嵌入式系统同步进程的竞态条件分析与推理学习方法

针对嵌入式系统同步进程的竞态条件问题,提出了一个竞态条件分析与推理模型,包括竞态依赖集、竞态协作图和竞态条件数组三要素。其中,模型分析并推理嵌入式系统中具有竞态关系的进程,生成竞态依赖集,定义竞态协作图来描述同步进程竞态条件关系,设计竞态条件数组来存储进程竞态逻辑推理关系以便进一步学习分析。该分析与推理学习方法提高了分析效率,具有一定的实用价值。

实时嵌入式系统的竞态条件及其分析方法研究

竞态条件使得多个任务对共享资源进行操作的先后顺序在不同的执行情况下发生改变,从而可能引起系统异常.为了分析实时嵌入式系统可能出现的竞态条件及其所带来的影响,根据目标系统的执行特征,建立系统的执行序列模型,对相关的竞态条件进行精确描述,并在此基础上提出一种竞态集来存储和分析系统的竞态条件,然后利用获取到的竞态集,构建系统的竞态条件图来预测系统潜在的竞态同步关系.实验分析表明该方法能够有效地分析和预测目标系统各种可能的竞态同步关系及其所带来的不同执行情况和结果.

基于SMT求解器的嵌入式多线程程序数据竞态条件分析

针对嵌入式多线程程序中出现的数据竞态条件,论文提出了一种基于SMT求解器数据竞态条件检测分析方法。通过对多线程程序执行路径与源程序分析,构建对应的约束条件,将其作为输入,SMT求解器验证是否满足数据竞态条件。通过实验,论文提出的嵌入式多线程程序数据竞态条件的分析与检测方法在检测效率上还是比较理想的。

基于硬件虚拟化的内核竞态漏洞监测技术研究与实现

内核竞态漏洞是一种新型漏洞,由于其产生原因特殊,导致巨大的安全威胁。通过对内核竞态漏洞产生原因、利用技术的分析,提出一种基于硬件虚拟化的监测方法。该方法利用Intel VT-x技术来构建一个轻量级虚拟监视器,依据竞态漏洞特征,通过对监视器系统CPU指令和可疑内存数据进行监控,实现对漏洞的全面监测;当可能的竞态情况出现时,利用收集的数据重构内核信息,动态定位漏洞位置。实验表明,该方法能够对内核竞态漏洞准确监测,具有较强的实用性。

Ajax应用中的竞态条件

在Web应用程序中,由于Ajax技术的异步特性,当客户端同时产生多个请求时,这些请求将在服务器端异步运行.由于无法预测这些请求的执行次序,如果它们在同一时间试图修改同一个关键数据片段,就可能导致在服务器响应时发生竞态条件问题.针对这个问题,分析了产生竞态条件的原理,给出了实例,对可能导致的安全问题进行了研究.结果表明,提出的锁定机制可以有效地避免竞态条件的产生.

一种可编程逻辑控制程序的竞态检测方法

针对可编程逻辑控制器中竞态检测的高计算复杂性,提出一种基于梯形图程序的特征结构用于检测竞态的方法.提出关系图的概念,并给出梯形图到关系图的转化方法.通过关系图的环形结构与可编程逻辑控制器的竞态之间的必然关系,给出梯形图中无竞态的判据.结果表明:该方法可以快速判断梯形图无竞态,并具有多项式级计算复杂度.

竞态漏洞检测方法综述

并行化程序运行环境中资源竞争导致的竞态漏洞是当今操作系统安全的重要威胁之一,攻击者常常间接利用竞态漏洞实施诸如远程命令执行、本地提权等攻击行为。分析了不同条件下竞态漏洞的产生机理及其相互关系,提出了竞态漏洞检测基本范式和通用框架,分别综述了用户态和内核态竞态漏洞检测方法的技术思想和发展脉络,讨论了制约检测效率的瓶颈问题以及可能的解决方法,结合最新技术应用指出了未来发展趋势和亟待解决的问题。

第20-24届冬奥会各项目竞态分布特征与镜鉴

以第20-24届冬奥会参赛代表团奖牌成绩为研究对象,分析各梯队代表团优势与潜优势项目分布特征。研究结果表明:以德国、挪威为首的第一梯队,优势与潜优势项目群涵盖范围广,夺牌优势大,在雪上项目上有着雄厚的统治力。奥地利、荷兰等第二梯队的7个代表团,优势与潜优势项目群涵盖单一,夺金率较低。第三梯队的意大利与日本的项目分布较为均衡,获奖项目逐年递增,竞技实力不断提升。我国在第24届冬奥会中改变了“冰盛雪弱”的局面,雪上项目取得新的突破,补填了诸多空白,但整体实力稍显落后,优势项目发挥不稳定,潜优势项目缺乏潜力,项目发展不均衡。

嵌入式系统的数据竞态条件研究

针对嵌入式系统中多线程的数据竞态条件问题,提出了一种基于图形的数据竞态条件分析方法,包括数据竞态条件分析算法、图形表示方法、线程竞争集、数据竞态图和二维数组五个部分。其中,数据竞态算法分析嵌入式系统中具有数据竞态关系的线程及其竞态关系构成线程竞争集,数据竞态图描述系统中同步多线程数据竞态条件关系,二维数组存储线程数据竞态逻辑,利用获得的数据竞态图推理系统中可能的其他线程数据竞态关系。

基于WinCE的电梯监控系统多串口通信实现

提出了一种基于WinCE的多串口电梯远程监控系统的实现方法。该方法以S3C2440微处理器为核心构建硬件平台,实现了与其他设备的串口通信;同时以WinCE5.0为软件平台,完成多串口分层流驱动的设计。通过文件映射,解决了访问多串口设备时产生的竞态问题。测试结果表明,该系统通信正常、数据稳定,能充分满足电梯监控对串行通信的要求。

Effects of Interspecific Competition on the Population Dynamics of Four Stored Grain Insect Pests

The effects of interspecific competition on the population dynamics of four insect grain Insecp pests （ Sitophilus zeamais, Rhizopertha dominica, Tribolium castaneum and Cryptolestes ferrugineus ） was studied at 30℃, 75% relative humidity. A regression analysis of the population dynamics was conducted. The results showed that population growth of S. zeamais , R. dominica, T. castaneum and C. ferrugineus was restrained under mixed rearing. Population growth of T. castaneum and C. ferrugineus was remarkably accelerated when they coexisted with S. zeamais or R. dominica, while that of S. zeamais and R. dominica was restrained to some extent. Regression analysis results showed that the population growth potential of S. zeamais was the largest and that of C. ferrugineus was the smallest, and the changing trends of population growth rates were not distinct.

福建省入境旅游客源市场分析

文章从福建省国际旅游客源市场结构特征及空间变化角度,运用旅游市场竞态模型,对2009~2018年福建省入境旅游相关数据进行了分析。结果显示,福建省入境旅游具有较好的海外市场及发展空间,且福建省入境旅游空间结构相对成熟,旅游中心地区与边缘地区入境旅游人次与收入相差较大,由此针对目前福建省入境旅游市场营销策略与福建省旅游空间布局提出相关建议,为福建省省内旅游的全面发展提供相应参考。

RELIABILITY EVALUATION MODEL BASED ON DATA FUSION FOR AIRCRAFT ENGINES

Reliability evaluation for aircraft engines is difficult because of the scarcity of failure data. But aircraft engine data are available from a variety of sources. Data fusion has the function of maximizing the amount of valu- able information extracted from disparate data sources to obtain the comprehensive reliability knowledge. Consid- ering the degradation failure and the catastrophic failure simultaneously, which are competing risks and can affect the reliability, a reliability evaluation model based on data fusion for aircraft engines is developed, Above the characteristics of the proposed model, reliability evaluation is more feasible than that by only utilizing failure data alone, and is also more accurate than that by only considering single failure mode. Example shows the effective- ness of the proposed model.

福建省入境旅游客源市场分析

本文从福建省国际旅游客源市场结构特征及空间变化角度,运用旅游市场竞态模型,对2009-2018年福建省入境旅游相关数据进行了分析。结果显示,福建省入境旅游具有较好的海外市场及发展空间,且福建省入境旅游空间结构相对成熟,旅游中心地区与边缘地区入境旅游人次与收入相差较大,由此提出针对目前福建省入境旅游市场营销策略与福建省旅游空间布局的相关建议,为福建省省内旅游的全面发展提供相应参考。

Evaluation of Ecological Environment Competitiveness of Hunan Province Based on Prefecture Level Cities

Based on the data of 13 eco-environmental indicators of 14 prefecture level cities in Hunan Province from 2014 to 2018,this paper quantitatively evaluated the eco-environmental competitiveness and its advantages and disadvantages by principal component analysis(PCA).The results showed that:(1)the overall ecoenvironmental competitiveness of Hunan Province was relatively high,whereas the competitiveness level of each city and prefecture was quite different.The comprehensive score of eco-environmental competitiveness of Changsha City was 2.96,ranking the first,and Zhangjiajie city ranking the last with a score of-1.60,which indicated that there was an obvious difference in the level of eco-environmental competitiveness among different regions.(2)The overall eco-environmental competitiveness of cities and prefectures in Western Hunan Province was weak.Among the 14 prefectures and cities in Hunan Province,the comprehensive scores of eco-environmental competitiveness of 6 prefectures and cities were negative,whereas the scores of Zhangjiajie,Xiangxi and Huaihua in Western Hunan were all lower than the others.In the face of increasingly serious environmental problems,cities and prefectures should adjust measures according to local conditions and put forward specific measures to enhance environmental competitiveness.In particular,cities and prefectures in Western Hunan should give full play to their advantages in ecological resources,take the path of green development,enhance the competitiveness of ecological environment,and provide support for local economic development.

Strategic thinking on improving the environmental competitiveness of Chinese enterprises

Environmental competitiveness, price competitiveness and non-price competitiveness make up the undivided vital part of product＇s competitiveness. Environmental competitiveness can not only help improve the enterprise＇s key competitiveness directly, but also strengthen it indirectly by improving the products＇ price competitiveness and non-price competitiveness effectively. Instead of being confined to the product itself, there are several element＇s that can determine and influence the product＇s environmental competitiveness, including the manufacturing process, the management of enterprise＆the life circle of the products, etc. Measuring these elements by setting “environmental suitable degree ”, and building up the echelon model to evaluate the environmental competitiveness can help us see about the standard of the enterprises＇ environmental competitiveness. Though many of the national enterprises have price competitiveness to some extend, restricted by all kinds of elements like systems, techniques, policy, the enterprises are weak in environmental competitiveness. Beginning with systems redesign, carrying out the sustainable development, strengthening inner enterprises management, making more efforts on technique innovation, and widely publicizing and teaching the ecological concept, Chinese national enterprises can improve their environmental competitiveness and improve their key competitiveness.

Assessing feeding competition between lake whitefish Coregonus clupeaformis and round whitefish Prosopium cylindraceum

We collected lake whitefish Coregonus clupeaformis and round whitefish Prosopium cylindraceum from the main basin of Lake Huron and Georgian Bay in the Laurentian Great Lakes of North America to investigate details of diet and feeding tactics of these species in different seasons. Lake whitefish supports important commercial fisheries in Lake Huron and both species make use of habitats near the Bruce Nuclear Power Development, on the eastern shore of Lake Huron. Most fish of both species showed generalist feeding behavior, but some lake whitefish appeared to show specialist prey selection. The invasive spiny water flea Bythotrephes longimanus was an important component of the diet of both species. There was considerable dietary overlap between the whitefish species, but the ecological implications of these dietary overlaps are mitigated by the fact that dominant prey species differed in most seasons. We conclude that the potential for ecologically significant interactions between lake whitefish and round whitefish resulting from competition for similar benthic food resources in the main basin of Lake Huron is probably low [Current Zoology 56 （1）： 109-117, 2010].

Measuring regional ecotourism competitiveness of Shandong Province based on Factor Analysis

Shandong Province is abundant in ecological resources to develop regional ecotourism.By using factor analysis method to analyze all possible influencing factors on regional ecotourism industry competitiveness,this article assesses 17 sample regions' competitiveness of ecotourism industry in Shandong.The regional ecotourism industry competitiveness is divided into two aspects:current competitiveness and potential competitiveness.13 indexes are to analyze current competitiveness and 7 indexes to analyze potential competitiveness respectively.Relative suggestions are given as well.

Intra-clutch variation in egg appearance assessed by human vision does not relate to rejection of parasite eggs in Iberian Azure-winged Magpies

e coevolutionary arms race between cuckoos and their hosts predicts that low variation in egg features within a host clutch would facilitate discrimination of mimetic parasite eggs.Here,we experimentally examine this prediction by using arti cial and natural parasite eggs showing contrasting level of matching with host eggs.We quanti ed,based on human assessment,intra-clutch variation in egg appearance and egg discrimination in the Iberian Azure-winged Magpie(Cyanopica cyanus),a presumed former host of the Great Spotted Cuckoo(Clamator glandarius).Azure-winged Magpies rejected parasitic eggs in relation to their degree of dissimilarity with own eggs:Great Spotted Cuckoo model eggs were relatively more o en rejected(73.7%) than real Great Spotted Cuckoo eggs(44.4%) and the less contrasting conspeci c eggs(35.5%).Contrary to our predictions,we found that,irrespective of mimicry level of parasitic eggs,intra-clutch variation in host egg appearance did not di er signi cantly between rejecters and acceptors.We found,however,that individuals with higher variation in egg-size were almost signi cantly more prone to be rejecters than individuals showing lower variation in egg size.Our results do not support the hypothesis that the extent of intraclutch variation in egg discrimination varied with parasite egg mimicry in this particular system,and add to previous ndings suggesting that perhaps an increase in intra-clutch variation in egg appearance,rather than a decrease,might be advantageous when discriminating against non-mimetic Great Spotted Cuckoo eggs.

A Focus： Epitomizing Approaches of Effective Employability Skills

The present paper reveals the pivotal challenges of fast changing global work environment and industrial needs. Employability skills need to be checked rather than unemployment problem in India. The paper further aims to explore the necessary skills to the challenges of globalizing trends. The issues, approaches, and remedial strategies are focused with reference to the people＇s skills. As the reflections of quality and competence depend on transparency and accountability of the organization, it is necessary to improve the required skills which enhance the levels of confidence. The potential employer＇s requirements are need to be worked very keenly by the institutions. The paper also deals with the effective learning process, which is at par with global counter parts. Exposure to the universal student-centered learning is emphasized to enhance the very crucial pace of work place. Finally this paper studies effective micro and macro issues regarding the dynamics of the industry by applying a broad range of employability skills complementing the technical skills.