Control of nonstationary LPV systems

This paper considers control of nonstationary linear parameter-varying systems, and is motivated by interest in the control of nonlinear systems along prespecified trajectories. In the paper, synthesis conditions are derived for such systems using an operator theoretical framework with the ?₂ induced norm as the performance measure. These conditions are given in terms of structured operator inequalities. In general, evaluating the validity of these conditions is an infinite dimensional convex optimization problem; however, if the initial system is eventually periodic, they reduce to a finite dimensional semi-definite programming problem. The paper concludes with an in-depth example on the control of a two-thruster hovercraft along an eventually periodic trajectory.     

Modified Kovarik Algorithm For Approximate Orthogonalization Of Arbitrary Matrices

In a previous paper the author presented an extension of an iterative approximate orthogonalization algorithm, due to Z. Kovarik, for arbitrary rectangular matrices. In this algorithm, as Kovarik already observed in his paper, at each iteration an inversion of a symmetric and positive definite matrix is made. The dimension of this matrix equals the number of rows of the initial one, thus the inverse computation can be very expensive. In the present paper we describe an algorithm in which the above matrix inversion step is replaced by an arbitrary odd degree polynomial matrix expression. We prove that this new algorithm converges to the same matrix as the original Kovarik's method. Some numerical experiments described in the last section of the paper show us that, even for small degree polynomial expressions the convergence properties of the new algorithm are comparable with those of the original one.     

基于虚拟现实的飞行保障指挥系统仿真

本文利用Multi-Creator建模,实现了机场布局及保障因素的虚拟现实,较为真实全面地反映了飞行保障环境;在此基础上,使用Vega对飞行保障过程进行数字仿真,用Matlab拟合物体运动路线,能够逼真地展现飞行保障细节、为指挥人员进行高效、准确、快速的决策提供支持。     

A meaning based information theory - informalogical space: Basic concepts and convergence of information sequences

This paper presents an information theory that is based on meanings and relationships between information. It first introduces the foundation of our approach, a binary relation contain between two pieces of information, based on inference between the two pieces of information. Then, based on the contain relation, it introduces two basic operations union and intersection on a collection (i.e., set) of information.This paper lays the foundation of our approach by introducing the core concept, informalogical space. An informalogical space is a collection of information that satisfies certain conditions represented in terms of the contain relation, and the union and intersection operations. An informalogical space is similar to a topological space in a symbolic sense, but is different in nature.This paper also introduces an information net in an informalogical space. An information net is a generalization of information sequence, just as a net is a generalization of sequence in general topology. This paper builds a convergence theory for information nets that is similar in a symbolic sense to the Moore-Smith convergence theory in general topology. Then, this paper applies the results for information nets to information sequences.     

Organic thin‐film devices on paper substrates

Abstract— A high‐performance polymer thin‐film transistor fabricated on a paper substrate has been demonstrated. As a water barrier layer, parylene was coated on a paper substrate by using a vacuum deposition process. Using poly (3‐hexylthiophene) as an active layer, a polymer thin‐film transistor with a field‐effect mobility of up to 0.086 cm²/V‐sec and an on/off ratio of 10⁴ was achieved. The fabrication of a polymer thin‐film transistor built on an inexpensive paper substrate is expected to open a channel for future applications in flexible and disposable electronics with extremely low cost.     

Sites of flux: imagining space in the dance-architectures of The Changing Room and Sea Unsea

This paper presents the conceptualization of an event space of interaction. Referring to enchantment as a means of describing an indeterminate and evolving state of interaction, where the meaning of the interactive object or environment remains open ended and exploratory, this paper explores how contemporary architectural concepts of space and inhabitation can allow for a new framing of interactive experiences. Presenting the two dance-architectures The Changing Room and Sea Unsea as case studies, the paper seeks to demonstrate challenges to the way space and place are understood in Human–Computer Interaction.     

A model measurement system for collaborative supply chain partners

The purpose of this paper is to understand business performance in the context of an electronic component company. This paper developed a system dynamics model that describes supply chain process structure and examines scenarios, as well. Thus, this study adopted the signal-to-noise (SN) ratio defined by the Taguchi method to evaluate the robustness of a specific supply chain behavior. Resulting in poor inventory cost performance with uncertainty demand, this paper shows how the factor delivery time and lead time of an order can improve performance. Finally, this paper serves as a guideline for decisions that require different inventory strategies.     

Information system artefact or information system application: that is the question

Lee et al. ( 2015 ) suggest the concept of information system (IS) artefact as an alternative to information technology (IT) artefact, defining the former as a system of an IT artefact, an information artefact and a social artefact. This paper assesses this suggestion, contrasting it with the concepts of IT artefact and IS application as introduced in the prior IS literature. After this conceptual analysis, the paper discusses the relationships between an IS artefact and design and between an IS artefact and design science. The analysis concludes that an IS artefact is problematic as a unit of design because of the great differences in the designability of its constituent parts. Instead, the paper maintains that an IS application is more appropriate as a unit of design, but an IS artefact may be fruitful as an analytical concept to be used in behavioural science research on the interplay of IT artefact, information artefact and social artefact, or – especially if including IS application design – in action research‐oriented design science research. © 2016 John Wiley & Sons Ltd     

Information flow for Algol-like languages

In this paper we present an approach to information flow analysis for a family of languages. We start with a simple imperative language. We present an information flow analysis using a flow logic. The paper contains detailed correctness proofs for this analysis. We next extend the analysis to a restricted form of Idealised Algol, a call-by-value higher-order extension of the simple imperative language (the key restriction being the lack of recursion). The paper concludes with a discussion of further extensions, including a probabilistic extension of Idealised Algol.     

An adaptive mesh refinement of quadrilateral finite element meshes based upon a posteriori error estimation of quantities of interest: linear static response

A posteriori error estimation in finite element analysis serves as an important guide to the meshing tool in an adaptive refinement process. However, the traditional posteriori error estimates, which are often defined in the energy or energy-type norms over the entire domain, provide users insufficient information regarding the accuracy of specific quantities in the solution. This paper describes an adaptive quadrilateral refinement process with a goal-oriented error estimation, in which a posteriori error is estimated with respect to the specified quantity of interest. A highlight of this paper is the demonstration of tools described in the paper used in a practical industrial environment. The performance of this process is demonstrated on several practical problems where the comparison is with the adaptive process based on the traditional error estimation.     

An efficient approach to representation and simplification of complex networks

This paper describes an efficient approach to representation and analysis of complex networks. Typically, an n node system is represented by an n × n connection matrix. This paper presents a new connection matrix representation scheme that uses three fields; “begin node”, “end node”, and “component id” to represent each node in the network. The proposed approach to connection matrix representation is more concise than the n × n matrix, which is often sparsely populated. This paper also describes network simplification algorithm based on the revised connection matrix. The algorithm when applied to a large system with 55 tie-sets reduced the network to a single tie-set.     

Finite horizon analysis of Markov Chains with the Murϕ verifier

In this paper we present an explicit disk-based verification algorithm for Probabilistic Systems defining discrete time/finite state Markov Chains. Given a Markov Chain and an integer k (horizon), our algorithm checks whether the probability of reaching an error state in at most k steps is below a given threshold. We present an implementation of our algorithm within a suitable extension of the Murϕ verifier. We call the resulting probabilistic model checker FHP-Murϕ (Finite Horizon ProbabilisticMurϕ). We present experimental results comparing FHP-Murϕ with (a finite horizon subset of) PRISM, a state-of-the-art symbolic model checker for Markov Chains. Our experimental results show that FHP-Murϕ can handle systems that are out of reach for PRISM, namely those involving arithmetic operations on the state variables (e.g. hybrid systems). This research has been partially supported by MURST projects MEFISTO and SAHARA. This paper is a journal version of the conference paper [16].     

Cooperation, Coordination and Interpretation in Virtual Environments: Some Thoughts on Working-Together

The need for information technology-mediated cooperation seems obvious. However, what is not obvious is what this means and what social demands such cooperation may imply. To explore this is the intention of the paper. As a first step the paper performs an etymological analysis of the words telecooperation and telecoordination. Such an analysis indicates that cooperation happens when people engage in the production of a work as if ‘one mind or body’, where their activities fuse together in a way that makes the suggestion of separation seem incomprehensible. In the work they do not merely aim to achieve an outcome, they also ‘insert’ themselves ‘in’ the work in a way that makes it a human achievement rather than a mere product – this is cooperation as working-together. With this notion of cooperation in mind the paper then proceeds to analyse the social conditions for cooperation as working-together. It shows, using the work of Wittgenstein, that language is fundamental to cooperation and the sharing of knowledge – not language as a system for the exchange of information but language as a medium for the co-creation of a local way of doing, a local language, to capture the local distinctions that make a particular local activity significant and meaningful to the participants. The paper then proceeds to question this strong notion of cooperation. It argues that most cooperative activities tend not to conform with such stringent demands. The paper suggests that a cooperative problem is best viewed as a situation in which ambiguity is accepted as a structural element of the interaction. From this perspective the paper suggests that hermeneutics may be a productive way to understand the creation of shared interpretative spaces that makes mediated cooperation possible. The paper concludes with some implications for mediated cooperative work.     

An anticipation mechanism for the shortest path problem based on Physarum polycephalum

In this paper, we put forward an anticipation mechanism for the existing Physarum-inspired shortest path finding method. The Physarum-based shortest path finding model can be implemented by an iterative algorithm and has wide applications in many fundamental network optimization problems. In this paper, we mainly focus on the Physarum-inspired shortest path tree model. Normally, we stop the program when the difference between two consecutive iterations is less than a predefined threshold. However, we do not know how to set the specific value for the threshold variable. In order to find out the optimal solution, we need to set the threshold as a very small number. This in turn will consume a lot of time. From this point of view, this algorithm lacks an efficient and reliable mechanism to judge when the optimal solution will be found. In this paper, we introduce an anticipation mechanism to address this issue. Numerical examples are used to demonstrate its reliability and efficiency.     

Generalized -KKM type theorems in topological spaces with an application

In this paper, we first introduce a new concept of generalized L-KKM mapping and establish some new generalized L-KKM type theorems without any convexity structure in topological spaces. As an application, an existence theorem of equilibrium points for an abstract generalized vector equilibrium problem is proved in topological spaces. The results presented in this paper unify and generalize some known results in recent literature.     

Pure bigraphs: Structure and dynamics

Bigraphs are graphs whose nodes may be nested, representing locality, independently of the edges connecting them. They may be equipped with reaction rules, forming a bigraphical reactive system (Brs) in which bigraphs can reconfigure themselves. Following an earlier paper describing link graphs, a constituent of bigraphs, this paper is a devoted to pure bigraphs, which in turn underlie various more refined forms. Elsewhere it is shown that behavioural analysis for Petri nets, π-calculus and mobile ambients can all be recovered in the uniform framework of bigraphs. The paper first develops the dynamic theory of an abstract structure, a wide reactive system (Wrs), of which a Brs is an instance. In this context, labelled transitions are defined in such a way that the induced bisimilarity is a congruence. This work is then specialised to Brss, whose graphical structure allows many refinements of the theory. The latter part of the paper emphasizes bigraphical theory that is relevant to the treatment of dynamics via labelled transitions. As a running example, the theory is applied to finite pure CCS, whose resulting transition system and bisimilarity are analysed in detail. The paper also mentions briefly the use of bigraphs to model pervasive computing and biological systems.     

Developing a well-being monitoring system—Modeling and data analysis techniques

This paper describes how complex data analysis algorithms are being employed to develop a new generation of telecare aimed at helping older people remain living more independently in their own homes for longer. The paper begins by explaining why governments throughout the world are encouraging the development and deployment of new telecare solutions—due in the main to a gradual but constant shift in demographics. Details of a new generation of telecare called ‘well-being monitoring’ being developed in the UK under the DTI (Department of Trade and Industry) NWTM initiative are provided, DTI [1]. The paper describes how the DTI funded ‘Care in the Community Centre’ led by BT, has developed a concept model to represent an individual's well-being. The paper goes on to provide an in depth explanation of the Intelligent Data Analysis techniques to be used for monitoring changes in well-being.     

The asymptotic model quality assessment for instrumental variable identification revisited

In this paper the problem of computing uncertainty regions for models identified through an instrumental variable technique is considered. Recently, it has been pointed out that, in certain operating conditions, the asymptotic theory of system identification (the most widely used method for model quality assessment) may deliver unreliable confidence regions. The aim of this paper is to show that, in an instrumental variable setting, the asymptotic theory exhibits a certain “robustness” that makes it reliable even with a moderate number of data samples. Reasons for this are highlighted in the paper through a theoretical analysis and simulation examples.     

Validating Simulation Models: A General Framework and Four Applied Examples

This paper provides a framework for discussing the empirical validation of simulation models of market phenomena, in particular of agent-based computational economics models. Such validation is difficult, perhaps because of their complexity; moreover, simulations can prove existence, but not in general necessity. The paper highlights the Energy Modeling Forum’s benchmarking studies as an exemplar for simulators. A market of competing coffee brands is used to discuss the purposes and practices of simulation, including explanation. The paper discusses measures of complexity, and derives the functional complexity of an implementation of Schelling’s segregation model. Finally, the paper discusses how courts might be convinced to trust simulation results, especially in merger policy.