数字取证的三维过程模型

在强调取证人员重要性的基础上,根据电子证据来源的不同,提出了一个三维过程模型,针对不同的案件中涉及的不同证据来源,可以采用不同的证据收集方案,扩大了数字取证模型的使用范围,同时实现了证据的自动收集和分析功能,及知识的重复使用功能,并在调查分析阶段对证据可靠性放大算法进行了改进,提高了证据的可靠性和工作效率。     

水书键盘输入系统研究与实现

水族文字被称为水书。为了满足水书研究者和出版业界的需要,设计了水字字符集的Unicode编码,利用字体制作软件建立了水字TrueType字库。该文提出了一种基于笔形特征的编码方法,依据编码规则取水字3个角的笔形组成有序序列,为水字编码。利用Windows系统的IMM-IME机制,实现了水字笔形输入法。     

Google Earth在森林植被营养元素循环研究中的应用

森林植被营养元素循环是森林生态系统分析中的重要参数.将Google Earth应用在其研究过程中具有重要作用.阐述了Google Earth的主要原理和关键技术,重点分析了KML和Google EarthAPI;设计了Google Earth应用的数据处理流程和系统架构;最后实现了基于Google Earth的贵州龙里森林植被营养元素循环研究系统.     

药物信息服务实践应用的信度与效度分析

为建立科学的药物信息服务评价体系,我们采用问卷调查法对新疆医科大学第四附属医院药房及患者信息进行系统性调查,利用Excel和SPSSStatistics进行数据整理分析,采用Cronbach＇sAlpha系数、因子分析等方法对问卷做了信度和效度评价分析,初步提出了医院药物信息服务的要素．结果,本次研究的过程和方法为他人在药物信息乃至其它信息分析中提供重要的参考依据．     

基于GPS和GPRS的嵌入式车载防盗系统

针对目前车辆防盗设备存在的问题及市场应用前景,提出了一种新型嵌入式车载防盗系统的设计方案.首先以S3C2410X为核心处理器、GPRS模块和GPRS模块搭建硬件平台,然后详细介绍了车载系统以及GPS和GPRS的软件设计.实验证明,本系统稳定可靠,通信效率高.对车载防盗系统的进一步实现具有参考价值.     

南水北调中线穿黄工程盾构机刀具维护技术

南水北调中线穿黄隧洞工程地质条件复杂,隧洞穿越地层有全砂层、全土层及上砂下土的复合地层。盾构机刀盘设计采用软土型刀具、重载型刀盘传力架,并采取了多种防磨损措施,以保护刀盘具。但在盾构施工过程中,掘进参数出现异常,且在出渣物中发现金属件,表明盾构机刀盘具受到严重磨损。通过带压进仓检查,及时查清了情况,更换了部分刀具,对需要修复的刀具,在对地基进行加固后,采用常压进舱方案,进行了彻底修复。本次刀盘具检查维护的经验,对于保证穿黄工程的顺利掘进具有重要的指导意义,对于其他类似工程也有重要的参考价值。     

Analysis of black water aggregation in Taihu Lake

Black water aggregation (BWA) in Taihu Lake is a disaster for the lake environment. It is a phenomenon resulting from water environmental deterioration and eutrophication caused by accumulation of pollutants in the lake, according to research on the water quality, pollutants of BWA, and occurrence mechanisms of BWA. Dead algae are the material base of BWA, the polluted sediment is an important factor for the formation of BWA, and hydrological and meteorological conditions such as sun light, air temperature,...     

某水源地地下水四氯化碳污染特征分析

通过对某水源地地下水的四氯化碳污染调查和日常监测数据分析,研究了该水源地四氯化碳污染晕的形态和变化特征,并选取典型水源井对其四氯化碳动态特征进行了分析。在污染发现初期,污染面积为2.73 km2,最高污染浓度为249.7μg/L,随着后期污染治理工作的开展,污染面积减小到1.24 km2,最高污染浓度下降到3.62μg/L。分析认为,污染晕形态在空间分布上主要受地下水流场的控制,同时受降水量、地下水位标高及开采量等多种因素控制,污染物由北区井群向南区井群扩散。单井四氯化碳含量动态则呈现出南北区的相反特征:在北区,四氯化碳含量随着地下水位的上升而上升,并随地下水流向南扩散;在南区,四氯化碳含量随着地下水位的上升而下降,并随地下水流向地下水漏斗中心汇集。这是由于赋存于SD1井附近包气带中的四氯化碳尚未清除造成的。     

An efficient accelerator for attribute reduction from incomplete data in rough set framework

Feature selection (attribute reduction) from large-scale incomplete data is a challenging problem in areas such as pattern recognition, machine learning and data mining. In rough set theory, feature selection from incomplete data aims to retain the discriminatory power of original features. To address this issue, many feature selection algorithms have been proposed, however, these algorithms are often computationally time-consuming. To overcome this shortcoming, we introduce in this paper a theoretic framework based on rough set theory, which is called positive approximation and can be used to accelerate a heuristic process for feature selection from incomplete data. As an application of the proposed accelerator, a general feature selection algorithm is designed. By integrating the accelerator into a heuristic algorithm, we obtain several modified representative heuristic feature selection algorithms in rough set theory. Experiments show that these modified algorithms outperform their original counterparts. It is worth noting that the performance of the modified algorithms becomes more visible when dealing with larger data sets.     

Meshfree simulations of spall fracture

Shock wave induced spall fracture is a complex multiscale phenomenon, and it is a challenge to build a constitutive and computational model that can capture essential features of the spall fracture. In this work, we present a computational micro-mechanics model to simulate spall fracture by utilizing the multiscale micro-mechanics theory proposed by Wright and Ramesh [36] and a RKPM meshfree method. The focus of this work is to develop and demonstrate a simulation tool that is capable of simulations of spall fracture in engineering application. First, based on a well-known empirical formula, we relate the macroscale spall strength to the kinematics of micro void growth in a Representative Volume Element (RVE). The connection between micro void growth and overall kinematics of the RVE is made through the conservation of mass in the micro to macro transition process. Second, we develop a set of meshfree void growth algorithms that is tailored to represent kinematics of void nucleation, growth and coalescence, and these algorithms retain the conservation of mass, momentum, and energy during simulations of ductile spall fracture. Third, based on the Johnson–Cook model, we developed a meshfree computational formulation, and we have carried out simulations of the spall fracture of a Ti–6Al plate under impact loads to validate the model. From the simulation, we find that the interaction between the first two inelastic wave pulses plays an important role in the mechanism of spall fracture. The numerical results show that the proposed method can capture some features of the spall fracture, and it may be used to simulate the spall fracture in engineering applications.