A Data Flow Approach to Procedural Modeling

Procedural models can simulate an object's behavior as well as its appearance. When combined with data flow methods, they provide a useful approach to image composition and animation.     

Toward Flexible Thermoelectric Flow Sensors: A New Technological Approach

A new technological approach on thin flexible sensors is presented. As proof of concept, a thermoelectric flow sensor on a 10-mum-thick polyimide foil has been realized. The advantages of silicon as a thermoelectric material and the stability of low-pressure chemical vapor deposition (LPCVD)-silicon nitride as a protective coating are combined with the flexibility of polymer substrates. The thermoelectric flow sensor is fabricated on a standard silicon wafer for handling purposes. Only the functional layers that are embedded in 600 nm of LPCVD-silicon nitride are transferred onto a 10-mum-thick polyimide. The bulk silicon has been removed using deep reactive ion etching. Samples have been fabricated and tested, proving the potential of this new technological concept. The first characterization results show that the sensor layout has to be adapted to the properties of the polymer substrate.     

一种基于数据流分析的故障序列生成方法

故障注入是一种测评容错机制的有效方法,它通过有意识地向目标系统引入故障来加速测试容错机制的试验过程.目前大多数故障注入实验中采用的故障序列都是通过随机抽样获取的,容易造成故障潜伏,从而导致容错机制的评测结果不准确.本文提出一种基于数据流分析的故障序列生成方法.提出<故障注入位置,故障注入时间,故障类型,故障掩码>的单粒子故障模型.在此基础上,通过数据流活跃变量分析计算得出故障注入位置属性,以及定值-引用分析确定了故障注入时间属性.并以PowerPC8548处理器和它对应的Trace模拟器为实验平台,验证了该故障序列生成方法具有90%以上的失效加速比,较好地解决了故障潜伏问题.     

A New Approach to Solving Data Clusterization Problems

A new approach to solving some problems of cluster analysis is proposed, which reduces a multi-dimensional problem to a one-dimensional one.     

A New ETL Approach Based on Data Virtualization

ETL (Extract-Transform-Load) usually includes three phases: extraction, transformation, and loading. In building data warehouse, it plays the role of data injection and is the most time-consuming activ...     

IXMDB：RDBMS中XML数据的一种全新存储模式

在RDBMS中存储XML数据有两种模式：Schema-conscious和Schema-oblivious。Schema-conscious模式不支持复杂的X-Path查询,Schema-oblivious模式在类型描述和访问过程中缺少灵活性。本文为MPEG-7文档提出了一个全新的存储方法：IXMDB。IXMDB吸取了Schema-conscious和Schema-oblivious的优点。同时避免了它们的主要缺点。IXMDB还为特殊数据类型提供了专门的存储机制。     

A Graph-Theoretic Approach to Default Logic

A network representation of propositional seminormal disjunction-free default theories is presented, leading to a graph-theoretic approach to their analysis. The problem of finding an extension is proved to be equivalent to that of determining a kernel for a corresponding graph, allowing stronger complexity results as well as new conditions for the existence of extensions.     

一种面向并行空间查询的数据划分方法

在并行空间数据库中,空间数据集在各计算节点是否聚集划分,对提高空间并行查询效率起着关键的作用.Oracle Spatial采用的基于格网的划分方法只考虑了数据集在各节点是否均衡划分,而未考虑空间数据的拓扑特征.基于空间数据聚集划分的目的,提出了一种基于K-平均聚类算法的空间数据划分方法.实验证明,该方法极大地提高了空间数据并行检索和查询效率.     

Enterprise Data Quality: A Pragmatic Approach

Enterprise data—the data that is created, used and shared by a corporation in conducting business—is a critical business resource that must be analyzed, architected and managed with data quality as a guiding principle. This paper presents results, practical insights, and lessons learned from a large scale study conducted in the telecommunications industry that synthesizes data quality issues into an architectural and management approach. We describe the real life case study and show how requirements for data quality were collected, how the data quality metrics were defined, what guidelines were established for intersystem data flows, what COTS (commercial off-the-shelf) technologies were used, and what results were obtained through a prototype effort. As a result of experience gained and lessons learned, we propose a comprehensive data quality approach that combines data quality and data architectures into a single framework with a series of steps, procedures, checklists, and tools. Our approach takes into account the technology, process, and people issues and extends the extant literature on data quality.     

一种基于预测建模的WSN数据管理方案

能效、满足用户多样化需求的传感器网络数据管理是当前传感器网络应用的一个重大挑战,本文在基于Proxy/Sensor分层传感器网络数据管理方式基础上,提出了一种新的传感器数据管理方案,利用用户的历史查询建立时间序列预测模型以推断用户的未来数据需求,基于预测结果从Sensor层节点获取感知数据并存储在Proxy层节点,同时Sensor层节点实时监测自身的负载状态,当负载达到阈值后主动上报历史感知数据,以提供对历史数据查询与分析的支持.实验结果表明该方案在满足用户数据需求的基础上,以较低的能耗和较小的查询时延获得了较为全面的性能.     

A New Approach to the Construction of Surfaces from Contour Data

This paper presents a new approach to the construction of a surface from a stack of contour slices. Unlike most existing methods, this new approach handles ambiguous conditions consistently without employing an algorithm to establish a correspondence between vertices on one contour and those on the next. It is easy to implement and fast to compute, requiring only basic geometric properties, namely closedness and simplicity, to be available with contour data. The advantages of this new approach have also been demonstrated with solutions to a few classical problems from the literature and some practical problems in medical imaging. It can also be applied to geographical surveying and keyframe animations.     

一种新的变异测试数据自动生成方法

变异测试是一种行之有效的软件测试方法,通过使用变异算子产生变异体系统地模拟软件中的各种缺陷,然后构造能够杀死这些变异体的测试数据集.自动生成能够杀死变异体的测试数据将提高变异测试的效率和有效性.当前的研究工作只考虑生成杀死单个变异体的测试数据.文中根据杀死同一位置的多个变异体的条件相近的特点,提出一种对杀死这些变异体的条件进行组合,然后生成同时杀死该位置多个变异体的测试数据的方法;给出相应的支持工具,并且通过实验验证方法的有效性.     

虚拟专用网络流量优化中的路由设计方法

本文在综述了虚拟专用网络(VPN)和相关技术后,进一步研究分析当前广域网中的常用的VPN拓扑结构及主要优缺点。设计了新的网络拓扑结构及数据包路由方法,详细介绍了设备ip设计、相关设备配置和数据包的流转举例,并总结了拓扑设计的主要优点,供用户参考。     

A Formal Logic Approach to Constrained Combinatorial Testing

Combinatorial testing is as an effective testing technique to reveal failures in a given system, based on input combinations coverage and combinatorial optimization. Combinatorial testing of strength t (t ≥ 2) requires that each t-wise tuple of values of the different system input parameters is covered by at least one test case. Combinatorial test suite generation algorithms aim at producing a test suite covering all the required tuples in a small (possibly minimal) number of test cases, in order to reduce the cost of testing. The most used combinatorial technique is the pairwise testing (t = 2) which requires coverage of all pairs of input values. Constrained combinatorial testing takes also into account constraints over the system parameters, for instance forbidden tuples of inputs, modeling invalid or not realizable input values combinations. In this paper a new approach to combinatorial testing, tightly integrated with formal logic, is presented. In this approach, test predicates are used to formalize combinatorial testing as a logical problem, and an external formal logic tool is applied to solve it. Constraints over the input domain are expressed as logical predicates too, and effectively handled by the same tool. Moreover, inclusion or exclusion of select tuples is supported, allowing the user to customize the test suite layout. The proposed approach is supported by a prototype tool implementation and results of experimental assessment are also presented.     

网络心跳包序列的数据流分簇检测方法

在对网络会话进行时序分析的基础上,提出基于数据流分簇处理的心跳包序列检测方法。对数据流进行时序分簇处理,按周期性特征扩充簇集合,筛除不符合特征的簇对象,根据稳定的簇集合检测心跳包序列。实验结果表明,该方法检测率较高、误检率较低,能够实现实时检测和处理。