A Fluid-Dynamic Traffic Model on Road Networks

We consider a mathematical model for fluid-dynamic flows on networks which is based on conservation laws. Road networks are studied as graphs composed by arcs that meet at some nodes, corresponding to junctions, which play a key-role. Indeed interactions occur at junctions and there the problem is underdetermined. The approximation of scalar conservation laws along arcs is carried out by using conservative methods, such as the classical Godunov scheme and the more recent discrete velocities kinetic schemes with the use of suitable boundary conditions at junctions. Riemann problems are solved by means of a simulation algorithm which processes each junction. We present the algorithm and its application to some simple test cases and to portions of urban network.     

一种基于直线模型的道路识别算法研究

为了提高道路识别的鲁棒性和抗干扰能力，提出了一种道路边缘识别算法。该算法的创新点在于采用自然边界作为道路识别的依据，同时算法也可以将白色路标作为识别道路边缘的标志。由于道路的自然边界不像车道标志线那样容易受到污染，因而使该算法具有了较高的鲁棒性。该算法是采用像素级特征和帧图像特征来识别道路边缘，可称为全局道路边界模型。在模型中由于采用了有关的道路约束条件，因而使得算法具有较好的抗干扰能力。该算法包括初始检测算法和跟踪算法两个部分，其中在跟踪算法中采用感兴趣区域算法(ROI)来限制检测区域，以提高实时性。最后，还提出了一个道路边界可信度检测函数，该函数可以用于计算道路边缘检测结果的可信程度。     

The Road to a Silicon Quantum Computer

We discuss prospects for building a silicon-based quantum computer with phosphorous donor qubits. A specific architecture is proposed for initial demonstrations; and the advantages and difficulties of thisapproach are described along with a plan for systematic development and calibration of the individualcomponents. PACS: 73.21.-b, 73.23.Hk, 81.16.-c, 85.35.-p, 85.40.Ry     

a(MDÆ): A Model Driven Approach to Multi-Dimensional Separation of Concerns with OCL

A typical activity in the object-oriented software engineering process involves the construction of a class structure in terms of which the system behaviour is to be specified. The behaviour, however, commonly consists of multiple tasks, each of which usually needs only part of the information available in that class structure. Additionally, a different representation of the required information may be appropriate. Therefore, it would be useful to be able to have multiple views on the global class structure, each being suitable for the specification of the behaviour related to a certain task. This paper introduces a(MDÆ)², a technique to realise such a strategy. It incorporates OCL as a powerful query language and advocates a model driven development process which relieves the developer from the burden of manually writing a considerable amount of tedious and error-prone code.     

Alienation: A Response to Stress

Abstract

Contemporary stress paradigms provide one basis for developing a systems theory that specifies causal linkages between social structure, alienation, and perceptual style. Within the proposed theory, five alienation syndromes serve as alternate methods of coping with psychological and physiobiochemical stress reactions. Stress levels derive from the countervailing influences of resources and social-structural stressors. The cognitive component of each alienation syndrome feeds back cybernetically to reduce psychological stress, while the affective component operates in an equivalent manner to reduce physiobiochemical stress.

Jointly, the two components also condition perceptual style. To reduce alienation, interventions that enhance resources are suggested for the intermediate range future. Planned changes to eliminate structural stressors are viewed as long-range efforts requiring future research.     

假新闻可以休矣！

我们看了“中国通用耗材”的假新闻可以休矣一文，认为在打印耗材领域内是一件值得大家重视的问题，特全文转载。请有关人士广泛探讨充分发表各自看法。现全文刊出如下。[编者按]     

From Computer Metaphor to Computational Modeling: The Evolution of Computationalism

In this paper, I argue that computationalism is a progressive research tradition. Its metaphysical assumptions are that nervous systems are computational, and that information processing is necessary for cognition to occur. First, the primary reasons why information processing should explain cognition are reviewed. Then I argue that early formulations of these reasons are outdated. However, by relying on the mechanistic account of physical computation, they can be recast in a compelling way. Next, I contrast two computational models of working memory to show how modeling has progressed over the years. The methodological assumptions of new modeling work are best understood in the mechanistic framework, which is evidenced by the way in which models are empirically validated. Moreover, the methodological and theoretical progress in computational neuroscience vindicates the new mechanistic approach to explanation, which, at the same time, justifies the best practices of computational modeling. Overall, computational modeling is deservedly successful in cognitive (neuro)science. Its successes are related to deep conceptual connections between cognition and computation. Computationalism is not only here to stay, it becomes stronger every year.     

A Scalable Model of Cerebellar Adaptive Timing and Sequencing: The Recurrent Slide and Latch (RSL) Model

From the dawn of modern neural network theory, the mammalian cerebellum has been a favored object of mathematical modeling studies. Early studies focused on the fanout, convergence, thresholding, and learned weighting of perceptual-motor signals within the cerebellar cortex. This led in the proposals of Albus (Mathematical Biosciences, vol. 10, pp. 25–61, 1971; Journal of Dynamic Systems, Measurement, and Control, vol. 97, pp. 220–227, 1975) and Marr (Journal of Physiology (London), vol. 202, no. 2, pp. 437–470, 1969) to the still viable idea that the granule cell stage in the cerebellar cortex performs a sparse expansive recoding of the time-varying input vector. This recoding reveals and emphasizes combinations (of input state variables) in a distributed representation that serves as a basis for the learned, state-dependent control actions engendered by cerebellar outputs to movement related centers. Although well-grounded as such, this perspective seriously underestimates the intelligence of the cerebellar cortex. Context and state information arises asynchronously due to the heterogeneity of sources that contribute signals to compose the cerebellar input vector. These sources include radically different sensory systems—vision, kinesthesia, touch, balance and audition—as well as many stages of the motor output channel. To make optimal use of available signals, the cerebellum must be able to sift the evolving state representation for the most reliable predictors of the need for control actions, and to use those predictors even if they appear only transiently and well in advance of the optimal time for initiating the control action. Such a cerebellar adaptive timing competence has recently been experimentally verified (Perrett, Ruiz, and Mauk, Journal of Neuroscience, vol. 13, no. 4, pp. 1708–1718, 1993). This paper proposes a modification to prior, population, models for cerebellar adaptive timing and sequencing. Since it replaces a population with a single element, the proposed Recurrent Slide and Latch (RSL) model is in one sense maximally efficient, and therefore optimal from the perspective of scalability.     

Usability Testing: A Journey, Not a Destination

Usability testing for interfaces can fit into a design project in several ways. The author looks at how good testing techniques can make projects run better and faster, and produce an improved result. The primary point is that there's no incompatibility between usability testing and a rational product process. We can think of usability testing as simply another aspect of quality assurance, and can fold it into the product process in much the same way as software quality assurance (QA). By having usability people involved from the beginning, big problems get found earlier, and small problems get found in time. The fear of losing control of a project to a usability person who finds a last-minute interface design problem is therefore a red herring. You can indeed find usability problems that might affect project completion late in the development process, just like you can find system architecture problems. But the way to keep this from happening is to test your system and your ideas during each stage of development, gathering the kind of information you need at each of those stages. That's why usability testing is a journey, not a destination     

Parametric Model of the Perspective Projection of a Road with Applications to Lane Keeping and 3D Road Reconstruction

This paper describes an algorithm for the computation of the 3D structure of a road and of the motion state of an in-vehicle CCD camera from the lane borders on the image plane. A parametric model of the projective projection of the lane borders on the image plane is introduced and a fast and reliable algorithm to compute its parameters is described. The physical significance of the model is demonstrated by showing that the model parameters completely determine the position of the vehicle inside the lane, its heading direction, and the local structure of the road. The conditions of applicability of the model are also given and the results of its application to a sequence of images taken during a test run discussed. The algorithm is suited to real time applications and indeed an implementation on the dedicated hardware of the mobile laboratory MOBLAB runs at a frame rate of 12 images per second.     

基于阶跃响应的FOPDT参数估计新方法

针对一阶惯性加纯滞后（first order plus dead time,FOPDT）模型,提出一种基于阶跃响应参数估计的新方法。该方法通过对模型输出变量的简单变换,将参数估计转换成一个最佳线性拟合问题。计算实例表明,利用该方法估计模型的参数是可行的,而且能够获得较精确的结果。     

Channel E-mail: A Sociotechnical Response to Spam

Spam wastes Internet processing, bandwidth, and storage. Like many other sociotechnical problems computing today faces, it's not solvable by purely technical approaches like filters or social responses like passing laws. Channel e-mail offers a solution that can enable social as well as technical communication efficiency.     

The RAMI On-line Model Checker (ROMC): A web-based benchmarking facility for canopy reflectance models

The exploitation of global Earth Observation data hinges increasingly on physically-based radiative transfer (RT) models. These models simulate the interactions of solar radiation within a given medium (e.g., clouds, plant canopies) and are used to generate look-up-tables that are embedded into quantitative retrieval algorithms, such as those delivering the operational surface products for MODIS, MISR and MERIS. An assessment of the quality of canopy RT models thus appears essential if accurate and reliable information is to be derived from them. Until recently such an undertaking was a time consuming and labour intensive process that was made even more challenging by the general lack of absolute reference standards. Several years of benchmarking activities in the frame of the RAdiation transfer Model Intercomparison (RAMI) exercise have now led to the development of the RAMI On-line Model Checker (ROMC). The ROMC is a web-based tool allowing model developers and users to autonomously assess the performance of canopy RT models (http://romc.jrc.ec.europa.eu/). Access to the ROMC is free and enables users to obtain both statistical and graphical indications as to the performance of their canopy RT model. In addition to providing an overall indication of the skill of a given model to correctly match the reference data, the ROMC allows also for interactive comparison/evaluations of different model versions/submissions of a given user. All ROMC graphs can be downloaded in PostScript format and come with a reference number for easy usage in presentations and publications. It is hoped that the ROMC will prove useful for the RT modeling community as a whole, not only by providing a convenient means to evaluate models outside the triennial phases of RAMI but also to attract participation in future RAMI activities.     

在弹射加速度作用下人体动态响应的数学模型辨识

本文介绍如何利用系统辨识方法,建立在弹射加速度作用下人体响应的数学模型,并对递推最小二乘法(RLS),递推增广最小二乘法(RELS),递推辅助变量法(RIV)三种辨识方法进行了比较.辨识的模型用于数字仿真取得了较好的效果.