Observing Human-Object Interactions: Using Spatial and Functional Compatibility for Recognition

Interpretation of images and videos containing humans interacting with different objects is a daunting task. It involves understanding scene/event, analyzing human movements, recognizing manipulable objects, and observing the effect of the human movement on those objects. While each of these perceptual tasks can be conducted independently, recognition rate improves when interactions between them are considered. Motivated by psychological studies of human perception, we present a Bayesian approach which integrates various perceptual tasks involved in understanding human-object interactions. Previous approaches to object and action recognition rely on static shape/appearance feature matching and motion analysis, respectively. Our approach goes beyond these traditional approaches and applies spatial and functional constraints on each of the perceptual elements for coherent semantic interpretation. Such constraints allow us to recognize objects and actions when the appearances are not discriminative enough. We also demonstrate the use of such constraints in recognition of actions from static images without using any motion information.     

Utility-based Multi-agent System with Spatial Interactions: The Case of Virtual Estate Development

A multi-agent system is presented here. Agent decisions are based on economic partial utilities. It’s a new computational tool using cellular and agent-based models. Decision processes are represented through computational agents. Land-use and land cover changes are represented through a cellular model. It belongs to kind of models called Multi-Agent Systems model of Land-Use Cover Change. Decisions concern the estate development in the neighborhood of the agents. Space is discretized in heterogeneous cells where heterogeneous agents interact together (directly or via space). Based on partial utility probabilities, several stochastic simulations are achieved. These simulations are then summarized, replicated and a parameter sensitivity analysis provided. The main parameters influencing the decisions of an agent depend on his type (ecologist, etc.) and on the expected economic activities in his neighborhood. Little information is assumed to be known about the mechanisms determining the parameter values guiding the decisions of the agents, except their type. The whole system constitutes a general virtual model, mostly independent from initial conditions and real data. Sensitivity analysis are used to explore behavioral paths and influencing parameters. In summary, the main contribution of this paper consists in: (i) defining a simulation-based framework for modeling the decisions of many heterogeneous economic agents involved in spatial interactions; (ii) capturing the decision process using general utility-based equations; (iii) providing a sensitivity analysis of initial parameter values. An example of possible application investigating strategies of various categories of agents (institutions, landowners, homeowners, etc.) facing an intense residential development is provided. The framework consists of abstracting institutional characteristics of actual local Urbanism Plan procedures in France. This model constitutes a first step to be further specified.     

Valuing Design Repair

One of the favorite activities in any of the architecture or design courses is to discuss antipatterns - design ideas hatched with good intentions that prove problematic over time. The few books on antipatterns focus primarily on introducing problems and straightforward solutions, which makes them hard to distinguish from better-known books that present design or programming guidelines or refactoring advice. However, there's a slight but significant difference between antipatterns and style guidance. A style guide typically covers good practices - what to do and what to avoid. An antipattern is somewhat more ambitious. It seeks to explain how good intentions can go awry and suggest meaningful ways to repair broken systems. The point isn't so much to say "do this" or "avoid doing that" as to suggest ways to prevent a problem or to skillfully apply a set of corrective actions.     

Valuing information technology infrastructures: a growth options approach

Decisions to invest in information technology (IT) infrastructure are often made based on an assessment of its immediate value to the organization. However, an important source of value comes from the fact that such technologies have the potential to be leveraged in the development of future applications. From a real options perspective, IT infrastructure investments create growth options that can be exercised if and when an organization decides to develop systems to provide new or enhanced IT capabilities. We present an analytical model based on real options that shows the process by which this potential is converted into business value, and discuss middleware as an example technology in this context. We derive managerial implications for the evaluation of IT infrastructure investments, and the main findings are: (1) the flexibility provided by IT infrastructure investment is more valuable when uncertainty is higher; (2) the cost advantage that IT infrastructure investment brings about is amplified by demand volatility for IT-supported products and services; (3) in duopoly competition, the value of IT infrastructure flexibility increases with the level of product or service substitutability; and (4) when demand volatility is high, inter-firm competition has a lower impact on the value of IT infrastructure.     

Symmetric Rank Codes

As is well known, a finite field _n = GF(q ⁿ ) can be described in terms of n × n matrices A over the field = GF(q) such that their powers A ⁱ , i = 1, 2, ..., q ⁿ – 1, correspond to all nonzero elements of the field. It is proved that, for fields _n of characteristic 2, such a matrix A can be chosen to be symmetric. Several constructions of field-representing symmetric matrices are given. These matrices A ⁱ together with the all-zero matrix can be considered as a _n -linear matrix code in the rank metric with maximum rank distance d = n and maximum possible cardinality q ⁿ . These codes are called symmetric rank codes. In the vector representation, such codes are maximum rank distance (MRD) linear [n, 1, n] codes, which allows one to use known rank-error-correcting algorithms. For symmetric codes, an algorithm of erasure symmetrization is proposed, which considerably reduces the decoding complexity as compared with standard algorithms. It is also shown that a linear [n, k, d = n – k + 1] MRD code _k containing the above-mentioned one-dimensional symmetric code as a subcode has the following property: the corresponding transposed code is also _n -linear. Such codes have an extended capability of correcting symmetric errors and erasures.     

Hacking Spaces: Place as Interface

In this article, we analyze the complex rationales—both transparent to us and, at times, made visible—underneath the instructional spaces in which we work and teach. To do so, we first situate space analysis in the larger, national conversations about instructional spaces and then through the work of computers and writing scholars. We conclude with an analysis of instructional spaces at our institution. These are spaces specific to our locale, but spaces we think are quite common at most institutions of higher education. Perhaps more importantly, we situate this space analysis on issues these spaces pose—issues of restricted movement, impaired ability to collaborate, sensory disruption, limited leadership ability, and functional/material constraints. We attempt to return to the roots of hacking and to situate hacking as a particular tool for negotiating and, at times, disrupting the assumptions built under, within, and across instructional spaces.     

混合秩矩阵分解模型

随着推荐系统的发展,矩阵近似算法成为研究热点,而以概率矩阵分解为代表的低秩矩阵近似模型因其具有较高的推荐精度而广受关注。但是,随着大数据时代的到来,评分矩阵越来越复杂,简单的单个矩阵近似模型会使一些隐藏在数据中的信息被忽视。为了解决这个问题,提出了一种基于boosting框架的混合秩矩阵近似算法(mixture rank matrix factorization,MRMF)。该算法基于boosting框架融合多个不同秩矩阵获取丰富的评分信息。具体方法为首先从整体结构出发,获取矩阵的整体信息,然后基于boosting求偏差获得残差矩阵,抓取局部的相关性。同时为了更好地学习局部特征,引入服从拉普拉斯先验分布的样本权重,构建自适应权重的概率矩阵模型(adaptive weight matrix factorization,AWMF)。在获取残差矩阵之后,通过EM算法学习残差矩阵的权重,避免模型过拟合以及减少人工调差的复杂度。实验结果验证,所提出的算法在四个真实数据集(Ciao、Epinions、Douban、Movielens(10M))上均具有较好的推荐精度。     

RT-Rank:基于RSS标签排名相关性的文档聚类

RSS文档聚合是Web 2.0的特色技术,目前RSS相关性阅读还仅限于简单的相同标签聚合.为解决此问题,提出了基于RSS标签聚类的新方法,主要工作包括:1)分析传统RSS聚合方法的不足之处;2)提出了RSS标签排名的概念和计算方法,将标签计数转化为了标签排名,消除了部分噪音;3)提出标签比重积累的RSS标签排名的Hash聚类方法;4)做了详实的实验.实验表明,新的RSS相关性文档聚类方法准确度提高了7%.     

Reduced Rank Kernel Ridge Regression

Ridge regression is a classical statistical technique that attempts to address the bias-variance trade-off in the design of linear regression models. A reformulation of ridge regression in dual variables permits a non-linear form of ridge regression via the well-known kernel trick. Unfortunately, unlike support vector regression models, the resulting kernel expansion is typically fully dense. In this paper, we introduce a reduced rank kernel ridge regression (RRKRR) algorithm, capable of generating an optimally sparse kernel expansion that is functionally identical to that resulting from conventional kernel ridge regression (KRR). The proposed method is demonstrated to out-perform an alternative sparse kernel ridge regression algorithm on the Motorcycle and Boston Housing benchmarks.     

Rank aggregation methods comparison: A case for triage prioritization

This paper seeks to test and to determine a suitable aggregation method to represent a set of rankings made by individual decision makers (DMs). A case study for triage prioritization is used to test the aggregation methods. The triage is a decision-making process with which patients are prioritized according to their medical condition and chance of survival on arrival at the emergency department (ED). There is a lot of subjective decision-making in the process which leads to discrepancies among nurses. Four rank aggregation methods are applied to the prioritization data and then an expert evaluates the results and judges them on practicality and acceptability. The proposed recommendation for preference aggregation is the method of the estimation of utility intervals. Expert opinion is highly valued in a decision-making environment such as this, where experience and intuition are key to successful job performance and outcomes.     

Supervision Based on Place Invariants: A Survey

The supervision based on place invariants (SBPI) is an efficient technique for the supervisory control of Petri nets. This paper reveals the significance of the SBPI based on a literature survey, applications, and an analysis of problems and supervisory settings that can be addressed using SBPI. Special attention is given to the various settings within which the problem can be formulated. Such settings can be distinguished based on the concurrency type, the type of controllability and observability, and the centralized or decentralized type of supervision. As we show, it is possible to approach the most general settings in a purely structural way, without resorting to reachability analysis. We begin by describing the SBPI problem and the literature methods that address this problem or are related to it. Then, we proceed to show classes of problems that can be reduced to the SBPI problem. In the SBPI, the specification is described as a system of inequalities that the Petri net marking must satisfy at any time. However, as we show, problems involving more general specifications can be approached in the SBPI setting, sometimes under additional assumptions, by performing net and/or specification transformations. Four of the specifications we will consider are logic constraints, language specifications, disjunctions of linear constraints, and liveness. We conclude with a presentation of possible applications of the SBPI approach to programming with semaphores, fault tolerance, and synchronic-distance based designs.     

信息系统等级保护测评

随着互联网技术的快速发展,信息系统对政府、机构、企业的日常工作和生产起到越来越重要的作用,信息系统的安全性、可用性和连续性越来越受到重视。开展信息系统的等级保护测评工作是评测系统安全性的必要手段,是检验系统整体的安全部署是否完善的有效方法。     

计算机等级考试系统安装与安全配置技术的探讨——福建省高校计算机等级考试系统的安装与安全配置技术

介绍基于Windows2003服务器及Windows XP客户端的局域网络环境下的,快速而又安全安装、配置考试服务器与数百台考试机的一项综合技术。结合我校实际情况,探索出一套较为可靠而又快捷的配置方案。     

基于排序集成的哈萨克语固定短语抽取

短语抽取是文本自动分类、主题提取及专利检索分析等文本信息理解等工作中都要应用到的一项关键技术。固定短语抽取作为短语研究的一部分,对短语标注、辞典编撰等自然语言处理任务都具有重要的现实意义。哈萨克语是黏着语,词形变化丰富,这些特点给哈语固定短语的抽取带来了一定的困难。提出一个总体的固定短语抽取算法,把固定短语抽取看作一个排序问题,使用C-value、互信息和log-likelihood进行抽取排序,并设计了一个新的排序集成方法对抽取的结果进行集成。实验分析结果表明,与单独的抽取算法比较,该算法达到了更高的准确率。     

Generalized Low Rank Approximations of Matrices

The problem of computing low rank approximations of matrices is considered. The novel aspect of our approach is that the low rank approximations are on a collection of matrices. We formulate this as an optimization problem, which aims to minimize the reconstruction (approximation) error. To the best of our knowledge, the optimization problem proposed in this paper does not admit a closed form solution. We thus derive an iterative algorithm, namely GLRAM, which stands for the Generalized Low Rank Approximations of Matrices. GLRAM reduces the reconstruction error sequentially, and the resulting approximation is thus improved during successive iterations. Experimental results show that the algorithm converges rapidly. We have conducted extensive experiments on image data to evaluate the effectiveness of the proposed algorithm and compare the computed low rank approximations with those obtained from traditional Singular Value Decomposition (SVD) based methods. The comparison is based on the reconstruction error, misclassification error rate, and computation time. Results show that GLRAM is competitive with SVD for classification, while it has a much lower computation cost. However, GLRAM results in a larger reconstruction error than SVD. To further reduce the reconstruction error, we study the combination of GLRAM and SVD, namely GLRAM + SVD, where SVD is preceded by GLRAM. Results show that when using the same number of reduced dimensions, GLRAM + SVD achieves significant reduction of the reconstruction error as compared to GLRAM, while keeping the computation cost low. Editor: Peter Flach