基于覆盖率的功能验证方法

随着半导体技术的发展,验证已经逐渐成为大规模集成电路设计的主要瓶颈。首先介绍传统的功能验证方法并剖析其优缺点,然后引入传统方法的一种改进——基于覆盖率的验证方法,最后介绍了基于覆盖率的验证方法在一款通用微处理器功能验证中的实际应用。     

Hybrid Approach to Faster Functional Verification with Full Visibility

For functional verification, software simulation provides full controllability and observability, whereas hardware emulation offers speed. This article describes a new platform that leverages the advantages of both. This platform implements an efficient scheme to record the internal behavior of an FPGA emulator and replay the relevant segment of a simulation in a software environment for debugging. Experimental results show an order-of-magnitude savings in debugging time compared to a software-only simulation approach.     

基于位矩阵编码实现模拟集成电路模块布局的遗传算法

提出了一种新的实现模拟集成电路模块布局的遗传算法，其位矩阵编码法提高了算法的搜索效率；模块的滑行处理使绝对布局问题转变成相对布局问题，极大地减小了搜索状态空间而不降低精度；复制过程中个体间的相似性检查避免了算法的早熟收敛；目标函数覆盖了模拟集成电路的特殊要求；正交实验的方法用来研究算法参数，其最优取值由另一个衍化遗传算法确定，多种电路的测试结果表明，该算法性能优于传统的模拟退火算法，布局结果与手工布局相仿，设计效率得到显著提高。     

A New Hybrid Approach to Handwritten Address Verification

The use of optical character recognition (OCR) has achieved considerable success in the sorting of machine-printed mail. The automatic reading of unconstrained handwritten addresses however, is less successful. This is due to the high error rate caused by the wide variability of handwriting styles and writing implements. This paper describes a strategy for automatic handwritten address reading which integrates a postcode recognition system with a hybrid verification stage. The hybrid verification system seeks to reduce the error rate by correlating the postcode against features extracted and words recognised from the remainder of the handwritten address. Novel use of syntactic features extracted from words has resulted in a significant reduction in the error rate while keeping the recognition rate high. Experimental results on a testset of 1,071 typical Singapore addresses showed a significant improvements from 24.0% error rate, 71.2% correct recognition rate, and 4.8% rejection rate using raw OCR postcode recognition to 0.4% error rate, 65.1% correct recognition rate, and 34.5% rejection rate using the hybrid verification approach. The performance of the approach compares favourably with the currently installed commercial system at Singapore Post, which achieved 0.7% error rate, 47.8% correct recognition rate, and 51.5% rejection rate for 6-digit postcode using the same test data.     

A Functional Approach to Picture Manipulation

A functional approach is used to investigate the creation and manipulation of pictures as hierarchical entities. A set of useful functions is designed and used in a series of illustrative examples written in the functional programming language HOPE. A functional animation system incorporating these ideas is then discussed.     

A Functional Approach to External Graph Algorithms

We present a new approach for designing external graph algorithms and use it to design simple, deterministic and randomized external algorithms for computing connected components, minimum spanning forests, bottleneck minimum spanning forests, maximal independent sets (randomized only), and maximal matchings in undirected graphs. Our I/ O bounds compete with those of previous approaches. We also introduce a semi-external model, in which the vertex set but not the edge set of a graph fits in main memory. In this model we give an improved connected components algorithm, using new results for external grouping and sorting with duplicates. Unlike previous approaches, ours is purely functional—without side effects—and is thus amenable to standard checkpointing and programming language optimization techniques. This is an important practical consideration for applications that may take hours to run.     

A Functional Approach to External Graph Algorithms

Abstract. We present a new approach for designing external graph algorithms and use it to design simple, deterministic and randomized external algorithms for computing connected components, minimum spanning forests, bottleneck minimum spanning forests, maximal independent sets (randomized only), and maximal matchings in undirected graphs. Our I/ O bounds compete with those of previous approaches. We also introduce a semi-external model, in which the vertex set but not the edge set of a graph fits in main memory. In this model we give an improved connected components algorithm, using new results for external grouping and sorting with duplicates. Unlike previous approaches, ours is purely functional—without side effects—and is thus amenable to standard checkpointing and programming language optimization techniques. This is an important practical consideration for applications that may take hours to run.     

一种基于场景的性质验证方法

顺序图是UML中重要的语法机制,用于对系统的动态行为进行建模。但是,建模后模型是否满足某方面性质却很难检验。为此,我们提出了一种基于场景的性质验证方法。该方法首先把描述一个场景的顺序图以及相关的状态图综合成一个“命题标记路径集”,把待验证的性质表示为有穷线性时序逻辑公式,然后利用“逆向标注”算法对其进行验
证。转化及验证过程均可自动完成。     

基于神经网络的网络验证码识别研究

本文首先介绍了神经网络的基本思想,提出了一种基于神经网络的网络验证码的识别方法,并利用开源的神经网络包JOONE用Java技术实现了验证码识别软件。最后通过训练样本对其进行了实验分析,取得了较高的识别率。     

网络协议的一种构建性验证方法

论文提出了多层自动机映射的思想,并应用此方法构建了复杂协议的构建性验证方法,同时给出了协议构建性验证的逻辑基础和构建步骤。此法有效地避免了复杂协议验证中状态组合爆炸问题。     

基于知识的印鉴鉴别方法

计算机印鉴鉴别是一项十分困难但又具有广泛应用背景的课题,国际上至今尚无实用有效的鉴别方法.本文从知识工程的角度出发,对印鉴鉴别中的启发式知识进行了深入的讨论.并在此基础上引入了一套完整的基于启发式知识的印鉴鉴别方法.该方法以启发式搜索获得配准关系,并根据启发式知识在其中提取一组结构特征,最后结合结构信息和统计模型作出判决.实验结果表明,该方法在可靠性、适应性和实用性方面比现有方法均有明显改进,已接近实用.     

An Interoperable Approach to Multifactor Identity Verification

Naming heterogeneity occurs in digital identity management systems when the various parties involved in managing digital identities use different vocabularies to denote identity attribute names. To resolve potential interoperability issues due to naming heterogeneity, the authors propose a new protocol that uses lookup tables, dictionaries, and ontology mapping techniques.     

A Survey of Hybrid Techniques for Functional Verification

This article surveys recent advances in hybrid approaches for functional verification. These approaches combine multiple verification techniques so that they complement one another, resulting in superior verification effectiveness.     

The Automata-Theoretic Approach to Verification of Reactive Systems

Basic problems related to the use of automata-theoretic methods of verification of reactive systems are considered; in particular, the construction of an automaton from a formula of a temporal logic and the reduction of the automaton being verified are described.     

一种自然图像中的建筑物目标验证方法

提出了一种对自然图像中候选的建筑物目标进行验证的方法。与传统的提取单一图像特征,利用少量先验知识进行验证的方法相比,该方法提取图像的边缘特征和短线段特征,通过建筑物图像中特征和特征分组的观察,将目标验证转化为给定候选目标的条件概率问题。利用贝叶斯理论,将建筑物目标的先验知识表现为一系列先验概率并计算后验概率的值,从而给出了一种新的目标验证方法。利用拍摄的自然图片进行实验表明：与传统的方法相比,该方法的识别性能有了一定程度的提高。     

基于二分决策图的特征模型验证方法

特征模型是领域分析活动产生的具有复用价值的软件需求模型.对特征模型的复用通常采用定制的方式.特征模型定制中的一个重要问题是验证问题.该问题的存在是因为特征之间往往具有一定的约束关系,而一个合法的定制结果必须保证特征之间所有约束关系的被满足性.由于特征模型验证问题NP-hard所具有的性质,如何高效地进行特征模型的验证就成为一件相对困难的事情.在深入挖掘特征模型验证问题特殊性的基础上,将这种特殊性和二分决策图的结构特点进行了有效的结合,提出了一种通过对二分决策图的一次遍历即能实现特征模型验证的方法.需要指出的是,该方法并非试图在一般意义上解决特征模型验证问题中NP-hard的困难性,而是尽可能地利用该问题的特殊性,以提高处理特征模型定制问题的规模和效率.实验数据表明,相比较以前采用的验证方法,基于BDD(binary decision diagram)的方法在处理特征模型验证问题的规模和效率上都具有显著的提高.     

An Integrated Approach to High Integrity Software Verification

Using automated reasoning techniques, we tackle the niche activity of proving that a program is free from run-time exceptions. Such a property is particularly valuable in high integrity software, for example, safety- or security-critical applications. The context for our work is the SPARK Approach for the development of high integrity software. The SPARK Approach provides a significant degree of automation in proving exception freedom. Where this automation fails, however, the programmer is burdened with the task of interactively constructing a proof and possibly also having to supply auxiliary program annotations. We minimize this burden by increasing the automation, through an integration of proof planning and a program analysis oracle. We advocate a ‘cooperative’ integration, where proof-failure analysis directly constrains the search for auxiliary program annotations. The approach has been successfully tested on industrial data.     

A Decomposed-model Predictive Functional Control Approach to Air-vehicle Pitch-angle Control

The requirements for the pitch-angle control of an air vehicle are a very fast response with as few vibrations as possible. The vibrations can damage the equipment that is carried within the body of the vehicle. The main problem to deal with is the relatively fast and under damped dynamics of the vehicle and the slow actuators and sensors. We have solved the problem by using a predictive approach. The main idea of this approach is a process output prediction based on a decomposed process model. The decomposition enables the extension of the model-based approach to processes with integrative behavior such as in the case of a rocket’s pitch-angle control. The proposed approach is not only useful in this case but it gives us a framework to design the control for a wide range of processes. We compared the predictive design methodology with the classical compensator control approach, known from aerospace system control. The advantage of the new approach is the reduced vibrations during the transient response.