Forward and Backward Simulations

A unified, comprehensive presentation of simulation techniques for verification of concurrent systems is given, in terms of a simple untimed automaton model. In particular, (1) refinements, (2) forward and backward simulations, (3) hybrid forward-backward and backward-forward simulations, and (4) history and prophecy relations are defined. History and prophecy relations are abstract versions of the history and prophecy variables of Abadi and Lamport, as well as the auxiliary variables of Owicki and Gries, Relationships between the different types of simulations, as well as soundness and completeness results, are stated and proved. Finally, it is shown how invariants can be incorporated into all the simulations. Even though many results are presented here for the first time, this paper can also be read as a survey (in a simple setting) of the research literature on simulation techniques. The development for untimed automata is designed to support a similar development for timed automata, Part II of this paper will show how the results of this paper can be carried over to the setting of timed automata.     

ADVISOR软件的混合仿真方法

该文首先介绍了前向仿真方法和后向仿真方法，分析了其工作原理和优缺点。接着描述了美国电动汽车仿真软件ADVISOR的混合仿真方法，它是以后向仿真方法为主，前向仿真方法为辅的混合仿真方法。然后以一混合动力汽车模型为例，分析了ADVISOR的工作原理。最后具体分析了一个典型仿真模块一车轮模块的模型，比较了其中的前向路径与后向路径的差异，具体说明了混合仿真方法的实现。该文对ADVISOR软件的应用具有参考作用。     

ADⅥSOR软件的混合仿真方法

该文首先介绍了前向仿真方法和后向仿真方法,分析了其工作原理和优缺点.接着描述了美国电动汽车仿真软件ADVISOR的混合仿真方法,它是以后向仿真方法为主,前向仿真方法为辅的混合仿真方法.然后以一混合动力汽车模型为例,分析了ADⅥSOR的工作原理.最后具体分析了一个典型仿真模块-车轮模块的模型,比较了其中的前向路径与后向路径的差异,具体说明了混合仿真方法的实现.该文对ADVISOR软件的应用具有参考作用.     

为何丽讯进 东芝退——2009年丽讯超预期300％完成30000台销量

2009年的国内投影机市场,用乱世来形容一点不为过.市场、品牌、渠道等层面变数颇多:全球金融海啸对投影机市场的影响仍在继续;老牌日系品牌退出中国市场的消息不断;各大厂商和渠道商分分合合,国内渠道格局大变.     

为何丽讯进 东芝退 2009年丽讯超预期300%完成30000台销量

2009年的国内投影机市场,用乱世来形容一点不为过。市场、品牌、渠道等层面变数颇多:全球金融海啸对投影机市场的影响仍在继续;老牌日系品牌退出中国市场的消息不断;各大厂商和渠道商分分合合,国内渠道格局大变。俗话说乱世出英雄,在充满变化的市场环境下,来自美国的投影品牌丽讯犹如一匹黑马,在2009年取得了骄人的成绩,令整个投影行业为之侧目。     

一种新的前后向扩散血管图像增强方法

提出一种新的血管图像去噪和锐化方法。在对血管多尺度分析的基础上,利用血管响应函数替代梯度,构建血管的一致性扩散系数。该扩散系数包含前向和后向扩散操作,在去除图像噪声的同时,可以锐化血管。在合成图像、肺小血管图像上进行仿真实验,结果表明,该方法适用于模糊的医学血管噪声图像,不仅能较好地去除噪声,而且能锐化血管边缘。     

A co-processed contour tracing algorithm for a smart camera

This paper describes a new approach for a contour-tracing algorithm targeting a low-power smart camera for industrial inspection. This embedded system consists of the three major components: CMOS sensor, FPGA and microprocessor. By analysing a linear-time algorithm used for simultaneously labelling connected components and their contours, two independent tasks could be identified. By efficiently assigning these two parts to the FPGA and the microprocessor achieving high-speed real-time operation is possible. The novelty of the proposed method is the development of a sequential co-processing algorithm for the FPGA. A Contour-Neighbourhood 3 × 3 filter kernel for converting the grey-level data to an intermediate representation containing directional information was added into an FPGA image-processing design. This pre-processed data is then provided to a software component which is executed on a microprocessor. The final result of this analysis is a sorted list of contour points for each object in the image. Further increases of the data throughput and the workload of the hardware resources are achievable by pipelining the subtasks of consecutive images. The runtime behaviour of this parallel operation is sufficient for meeting the real-time requirements of an industrial 2D measurement system.     

基于双向推理的主体框架

文章提出了一个基于双向推理的主体框架FBRA,它是一个混合型的主体框架,主体既是反应的又是慎思的。它的推理内核是正向推理和反向推理相结合。正向推理用于对环境的反应,包括对其他主体的反应。反向推理基于溯因推理,用于信念修正、规划、多主体协调和多主体通信等。     

一种前后向复扩散图像增强算法

传统的图像增强算法无法在去除噪声的同时保留图像的纹理.为此,本文从线性前向复扩散的原理出发,研究了线性后向复扩散的图像增强功能,将前向复扩散和后向复扩散相结合,给出了一种前后向复扩散图像增强算法.实验结果表明:该算法抑制了图像中的微弱噪声,有效地增强了图像,保留了图像的细节纹理,没有产生错误的图像增强效果,可以获得很好的图像增强效果.     

Observability and Forward–Backward Observability of Discrete-Time Nonlinear Systems

 In this paper we study the observability properties of nonlinear discrete-time systems. Two types of contributions are given. First we present observability criteria in terms of appropriate codistributions. For particular, but significant, classes of systems we provide criteria that require only a finite number of computations. Then we consider invertible systems (which includes discrete-time models obtained by sampling continuous-time systems) and prove that the weaker notion of forward–backward observability is equivalent to the stronger notion of (forward) observability. Date received: January 19, 2001. Date revised: May 14, 2002.     

A contour tracing and coding algorithm for generating 2D contour codes from 3D classified objects

In 3D image data sets generated by voxel-based classification, each voxel is marked with a specific class label. Voxels of the same class label can form 3D objects of extremely complex shape. Interactively drawn regions are usually represented by their 2D region borders. In order to combine automatically classified with interactively drawn regions, a contour tracing and coding algorithm for generating optimized 2D contours from 3D classified objects is presented. A special conversion algorithm allows a chain or a crack code representation. An application to medical images shows the method's necessity and usefulness in dealing with highly complex regions.     

基于前后向线性预测的时变参数估计方法研究

在基时间函数展开理论基础上,通过同时引入非平稳信号的前向线性预测和后向线性预测来估计模型的时变系数,提出了一种新的时变参数建模方法,有效地克服了现有方法对瞬时频率估计的滞后问题和无法准确估计初始时刻值的困难;仿真试验证明,在相同阶次和基函数维数条件下,该方法对非平稳信号瞬时频率的估计效果要优于现有的方法。     

Monotonic Extensions of Petri Nets: Forward and Backward Search Revisited

In this paper, we revisit the forward and backward approaches to the verification of extensions of infinite state Petri Nets. As contributions, we propose an efficient data structure to represent infinite downward closed sets of markings and to compute symbolically the minimal coverability set of Petri Nets, we identify a subclass of Transfer Nets for which the forward approach generalizes and we propose a general strategy to use both the forward and the backward approach for the efficient verification of general Transfer Nets.     

Forward变换器的精确线性化控制

为了提高Forward变换器非线性系统的控制性能,采用了精确线性化控制方法。首先采用开关函数和开关周期平均算子建立适合微分几何方法的仿射非线性系统模型。从理论上证明了该模型满足系统精确线性化的条件。对非线性坐标变换后得到的线性系统,利用二次型最优控制策略推导出非线性状态反馈控制律。实验结果表明,系统具有良好的静态和动态性能,验证了该控制方法的有效性和正确性。     

A Logical Characterization of Forward and Backward Chaining in the Inverse Method

The inverse method is a generalization of resolution that can be applied to non-classical logics. We have recently shown how Andreoli’s focusing strategy can be adapted for the inverse method in linear logic. In this paper we introduce the notion of focusing bias for atoms and show that it gives rise to forward and backward chaining, generalizing both hyperresolution (forward) and SLD resolution (backward) on the Horn fragment. A key feature of our characterization is the structural, rather than purely operational, explanation for forward and backward chaining. A search procedure like the inverse method is thus able to perform both operations as appropriate, even simultaneously. We also present experimental results and an evaluation of the practical benefits of biased atoms for a number of examples from different problem domains. This work has been partially supported by the Office of Naval Research (ONR) under grant MURI N00014-04-1-0724 and by the National Science Foundation (NSF) under grant CCR-0306313. The first author was partially supported by a post-doctoral fellowship from INRIA-Futurs/école Polytechnique.     

Track based relevance feedback for tracing persons in surveillance videos

While surveillance cameras are a powerful tool for the prevention, detection and resolving of crimes, for most cases the amount of video data has become unmanageable. To ease the analysis, various automatic methods have been proposed, focusing on data-management, detecting suspicious behavior, person recognition, or event reconstruction. In this paper we focus on event reconstruction, in particular on tracing the whereabouts of people. The standard approach for such event reconstruction is to first detect persons in single frames and then match a query to all detections to retrieve the same person in multiple cameras. However, since the number of detected persons is large and performance of matching techniques limited, this process is slow and prone to errors. Intelligent interactive techniques are urged for. We propose to represent detected persons by their complete track within a single camera instead of a single detection and thereby reduce the search-space. On these tracks we use Relevance Feedback to improve recall with only a small effort of the user. Testing the tracking method on a benchmark dataset and a real-life dataset led to a reduction of the search space of 90%, while tracing accuracy based on the distance between tracks improved recall by up to 110% when compared to random tracing. Adding Relevance Feedback led to an additional improvement in recall of up to 400% compared to sequential scanning using the same number of visual assessments.     

储煤场装载过程追溯与反馈系统设计

针对目前储煤场作业监管效率低的问题,设计了一种基于GPS的储煤场装载过程追溯与反馈系统,阐述了基于STM32F103VET6的装载机装运定位终端设计方案。该系统采用GPS技术,在存储区域设定屯煤区电子围栏,根据煤炭种类的分布将屯煤区划分为多个煤种存储区域;定位终端通过GPRS网络将装载机的GPS定位信息等实时上传到服务器,实现装载过程实时记录、分析和有效监管;系统可与煤矿现有过磅系统连接,将过磅数据实时反馈到定位终端,以提高装载效率。     

Automatic shape quantification of freely suspended red blood cells by isodensity contour tracing and tangent counting

In several blood diseases, the resting red blood cells show deviations from the normal discoidal shape. This is of great diagnostic importance. Similar shape changes occur if cells are subjected to various physical and chemical treatments. An automatic on-line method is introduced which can quantify the mean shape of such cells, freely suspended and unaltered by the method. With the cells inside a special flow chamber, pictures are taken in the form of optical sections using a CCD camera. The image processing includes digitization, cumulation of regions of interest (ROI), contour determination by two-dimensional histogram and isodensity contour tracing, chain coding and tangent counting. The method determines the mean of the absolute number of tangents per section Ts, a quantitative unique shape factor, which allows quantification of pathological red blood cell shapes and follow-up shape changes in experiments, and makes different experiments quantitatively comparable.     

Lip segmentation using localized active contour model with automatic initial contour

Lip-reading is one of important approaches for human–computer interaction (HCI). Its development would have a large range of applications, especially in augmented reality. Lip segmentation is the first and foremost step in the lip-reading system. Conventional method of region-based active contour model adopts the global information of image and is unable to perform well. In this paper, from a localized perspective, we introduce the methodology of localized active contour model (LACM) and, meanwhile, propose the method that using LACM to perform the lip segmentation with the initial contour automatically generated. The scope for active contour model is reduced to the local region that reduces the disturbances of unrelated factors. The experimental results demonstrate the method adopts this model would dramatically improve the robustness for lip segmentation. On this basis, we analyze the influence of initial contours and local radiuses, study the efficiencies under different initial contours and compare it with the conventional active contour model which adopts the global information.