Completeness of type assignment in continuous lambda models

The completeness of Curry's rules for assigning type schemes to terms of the pure lambda-calculus has been proved by Hindley (1983) and Barendregt et al. (1983) using models of syntactic nature. A first result of this paper is a completeness proof with respect to the model P_ω (as asked by Scott (1976)). Moreover, an extension of Curry's system in which type schemes can be assigned to the fixed point combinator is introduced, together with a notion of type semantics for which it is proved sound and complete (answering a question of Scott (1980)). Also in this case, completeness is proved with respect to the model P_ω. All results also hold for the alternative notions of type semantics proposed by Hindley (1983) and Scott (1976, 1980).     

On relationships among passivity,positive realness,and dissipativity in linear systems

The notions of passivity and positive realness are fundamental concepts in classical control theory, but the use of the terms has varied. For LTI systems, these two concepts capture the same essential property of dynamical systems, that is, a system with this property does not generate its own energy but only stores and dissipates energy supplied by the environment. This paper summarizes the connection between these two concepts for continuous and discrete time LTI systems. Beyond that, relationships are provided between classes of strictly passive systems and classes of positive real systems. The more general framework of dissipativity is introduced to connect passivity and positive realness and also to survey other energy-based results. The frameworks of passivity indices and conic systems are discussed to connect to passivity and dissipativity. After surveying relevant existing results, some clarifying results are presented. These involve connections between classes of passive systems and finite-gain _L2$L_2$ stability as well as asymptotic stability. Additional results are given to clarify some of the more subtle conditions between classes of these systems and stability results. This paper surveys existing connections between classes of passive and positive real systems and provides results that clarify more subtle connections between these concepts.     

Augmented reality technologies,systems and applications

This paper surveys the current state-of-the-art of technology, systems and applications in Augmented Reality. It describes work performed by many different research groups, the purpose behind each new Augmented Reality system, and the difficulties and problems encountered when building some Augmented Reality applications. It surveys mobile augmented reality systems challenges and requirements for successful mobile systems. This paper summarizes the current applications of Augmented Reality and speculates on future applications and where current research will lead Augmented Reality’s development. Challenges augmented reality is facing in each of these applications to go from the laboratories to the industry, as well as the future challenges we can forecast are also discussed in this paper. Section 1 gives an introduction to what Augmented Reality is and the motivations for developing this technology. Section 2 discusses Augmented Reality Technologies with computer vision methods, AR devices, interfaces and systems, and visualization tools. The mobile and wireless systems for Augmented Reality are discussed in Section 3. Four classes of current applications that have been explored are described in Section 4. These applications were chosen as they are the most famous type of applications encountered when researching AR apps. The future of augmented reality and the challenges they will be facing are discussed in Section 5.     

Recent advances in simultaneous localization and map-building using computer vision

Simultaneous localization and map-building (SLAM) continues to draw considerable attention in the robotics community due to the advantages it can offer in building autonomous robots. It examines the ability of an autonomous robot starting in an unknown environment to incrementally build an environment map and simultaneously localize itself within this map. Recent advances in computer vision have contributed a whole class of solutions for the challenge of SLAM. This paper surveys contemporary progress in SLAM algorithms, especially those using computer vision as main sensing means, i.e., visual SLAM. We categorize and introduce these visual SLAM techniques with four main frameworks: Kalman filter (KF)-based, particle filter (PF)-based, expectation-maximization (EM)-based and set membership-based schemes. Important topics of SLAM involving different frameworks are also presented. This article complements other surveys in this field by being current as well as reviewing a large body of research in the area of vision-based SLAM, which has not been covered. It clearly identifies the inherent relationship between the state estimation via the KF versus PF and EM techniques, all of which are derivations of Bayes rule. In addition to the probabilistic methods in other surveys, non-probabilistic approaches are also covered.     

Nonquadratic cost and nonlinear feedback control

Nonlinear controllers offer significant advantages over linear controllers in a variety of circumstances. Hence there has been significant interest in extending linear-quadratic synthesis to nonlinear-nonquadratic problems. The purpose of this paper is to review the current status of such efforts and to present, in a simplified and tutorial manner, some of the basic ideas underlying these results. Our approach focuses on the role of the Lyapunov function in guaranteeing stability for autonomous systems on an infinite horizon. Sufficient conditions for optimality are given in a form that corresponds to a steady-state version of the Hamilton-Jacobi-Bellman equation. These results are used to provide a simplified derivation of the nonlinear feedback controller obtained by Bass and Webber (1966)³⁸ and to obtain a deterministic variation of the stochastic nonlinear feedback controller developed by Speyer (1976).⁴⁵.     

Linguistic probabilities: theory and application

Over the past two decades a number of different approaches to “fuzzy probabilities” have been presented. The use of the same term masks fundamental differences. This paper surveys these different theories, contrasting and relating them to one another. Problems with these existing approaches are noted and a theory of “linguistic probabilities” is developed, which seeks to retain the underlying insights of existing work whilst remedying its technical defects. It is shown how the axiomatic theory of linguistic probabilities can be used to develop linguistic Bayesian networks which have a wide range of practical applications. To illustrate this a detailed and realistic example in the domain of forensic statistics is presented.     

Inclusion,subsumption, JJ‐paths,and structured path testing: a Redress

Introduced in 1976 by Hennell, Woodward, and Hedley, the Linear Code Sequence and Jump (LCSAJ) has since been named the jump‐to‐jump path (JJ‐path). If all JJ‐paths in a piece of code have been tested, then it is guaranteed, for example, that all of the code's branches and all of its statements will likewise have been tested. JJ‐path testing is thus said to include both branch and statement testing. Over the years, much work has been carried out on the inclusion relation, and this is also true of a closely‐linked relation that is known as subsumption. Not surprisingly, some of the work in the literature has focussed on the criteria of executing all JJ‐paths and sequences of such, and how these criteria relate to other path coverage and test data criteria. Unfortunately, certain results involving JJ‐paths in the context of inclusion, as portrayed in a widely referenced and influential paper, are in error. Consequently, the main purpose of this paper is to rectify this situation. Copyright © 2008 John Wiley & Sons, Ltd.     

Enhancement of robustness in observer-based fault detection†

A prerequisite for the feasibility of the technique of observer-based fault detection and isolation (FDI) in dynamic systems is a satisfactory robustness with respect to modelling uncertainties. This paper surveys the most relevant methods to increase the robustness in both the stage of residual generation and residual evaluation. Among these methods are the generalized observer scheme, the robust parity space check, the unknown input and H _∞ observer scheme, the decorrelation filter, and the concept of adaptive threshold selection. It is pointed out that the unknown input observer concept, which provides perfect decoupling from the modelling errors or its optimal approximation with the aid of H _∞ techniques, constitutes a general framework of robust residual generation that generalizes and unifies numerous other approaches, among them the parity space and detection filter approach. It is further shown that this FDI method can even be applied to a certain class of nonlinear systems.     

Microcomputer maintenance in schools-a survey of current practice

Abstract  This paper is an outline report of larger study dealing with the topic of computer maintenance in schools. It examines the responses to surveys of schools, a maintenance firm and English LEAs. The results of these surveys are given showing, in the main, that maintenance is a neglected aspect of the introduction of IT in schools. It is argued that this has implications for both teaching and resource use.     

Shirking behavior and socially desirable responding in online surveys: A cross-cultural study comparing Chinese and American samples

Respondents of online surveys may exhibit some answering behaviors, which lead to inconsistent survey results between online surveys and traditional paper surveys. Extant research has not yet devoted sufficient effort to the mechanisms of different answering behaviors on the inconsistent results, especially in cross-cultural survey contexts. For this reason, this study examines how shirking behavior (i.e., a form of disengaged behavior that the respondents expend insufficient mental effort on the questionnaire) and socially desirable responding result in incomparable responses between online surveys and paper surveys. We especially investigate how the cultural constructs of individualism and collectivism relate to shirking and social desirability. Our results reveal two different pathways leading to inconsistent results across different survey modes. Respondents from collectivistic cultures are more likely to shirking in online surveys. Consequently, they are more likely to provide varying responses than respondents from individualistic cultures. Collectivists are more likely to engage in impression management in paper surveys than in online surveys, while individualists have a greater tendency to provide inflated assessments of their skills and abilities in both survey modes.     

Beauty is more than screen deep: Improving the web survey respondent experience through socially-present and aesthetically-pleasing user interfaces

Web surveys are rapidly becoming standard issue in many researchers’ toolkits; however, measurement error has been shown to affect web surveys to a greater extent than paper-and-pencil surveys (Couper, 2000, Manfreda and Vehovar, 2002). Principles of aesthetic design and social presence have been applied to web surveys to reduce the prevalence of such error with promising results, which were further investigated in this research. A sample of 181 first-year psychology undergraduate students participated in this study. Participants were randomly allocated to view one of eight web survey interfaces, which varied by aesthetic quality and social presence. Exploratory structural equation modeling using the partial least squares method revealed that classical aesthetic quality and social presence were both positively related to perceived ease of use of the web survey interface and positive state affect; social presence and perceived ease of use were positively related to trust in the web survey researcher; classical aesthetic quality was negatively related to negative state affect; and, expressive aesthetic quality was negatively related to perceived ease of use and positively related to positive state affect. Interestingly, expressive aesthetic quality was also positively related to negative state affect. These relationships between aesthetic quality and social presence should inform best practice web survey design recommendations, and future empirical work should extend and test the generalizability of these findings.     

Low Degree Solutions to Linear Equations with K[x] Coefficients

For given f1,…,fm ϵ K[x] which are relatively prime we present degree bounds on the a_i needed to express 1 and other "low degree" polynomials as ∑a_if_i. This paper gives an improvement on Kakié's bound (Kakié, 1976).     

Dynamics of the Binary Euclidean Algorithm: Functional Analysis and Operators

We provide here a complete average-case analysis of the binary continued fraction representation of a random rational whose numerator and denominator are odd and less than N . We analyze the three main parameters of the binary continued fraction expansion, namely, the height, the number of steps of the binary Euclidean algorithm, and finally the sum of the exponents of powers of 2 contained in the numerators of the binary continued fraction. The average values of these parameters are shown to be asymptotic to A _i log N , and the three constants A _i are related to the invariant measure of the Perron—Frobenius operator linked to this dynamical system. The binary Euclidean algorithm was previously studied in 1976 by Brent who provided a partial analysis of the number of steps, based on a heuristic model and some unproven conjecture. Our methods are quite different, not relying on unproven assumptions, and more general, since they allow us to study all the parameters of the binary continued fraction expansion. Received February 9, 1998; revised March 15, 1998.     

Asymptotic properties of subspace estimators

Since the proposal of subspace methods in the 1980s and early 1990s substantial efforts have been made in the analysis of the statistical properties of the algorithms. This paper surveys the literature on the asymptotic properties of particular subspace methods used for linear, dynamic, time invariant, discrete time systems. The goals of this paper are threefold: First this survey tries to present the most relevant results on the asymptotic properties of estimators obtained using subspace methods. Secondly the main methods and tools that have been used in the derivation of these results are presented to make the literature more accessible. Thirdly main unsolved questions and rewarding research topics are identified some of which can be attacked using the toolbox discussed in the paper.     

A GPS/GIS method for travel mode detection in New York City

Handheld GPS provides a new technology to trace people’s daily travels and has been increasingly used for household travel surveys in major cities worldwide. However, methodologies have not been developed to successfully manage the enormous amount of data generated by GPS, especially in a complex urban environment such as New York City where urban canyon effects are significant and transportation networks are complicated. We develop a GIS algorithm that automatically processes the data from GPS-based travel surveys and detects five travel modes (walk, car, bus, subway, and commuter rail) from a multimodal transportation network in New York City. The mode detection results from the GIS algorithm are checked against the travel diaries from two small handheld GPS surveys. The combined success rate is a promising 82.6% (78.9% for one survey and 86.0% for another). Challenges we encountered in the mode detection process, ways we developed to meet these challenges, as well as possible future improvement to the GPS/GIS method are discussed in the paper, in order to provide a much-needed methodology to process GPS-based travel data for other cities.     

Polynomial learnability and Inductive Logic Programming: Methods and results

Over the last few years, the efficient learnability of logic programs has been studied extensively. Positive and negative learnability results now exist for a number of restricted classes of logic programs that are closely related to the classes used in practice within inductive logic programming. This paper surveys these results, and also introduces some of the more useful techniques for deriving such results. The paper does not assume any prior background in computational learning theory.     

RSS — a primer for publishers and content providers

The key observation about institutional research repositories is that they are under used. This paper looks at why take-up has been slow, and what might encourage researchers to use these facilities. This paper surveys the evolution of practice and rationale for the institutional research repository, looks at existing use studies and opinion surveys of users, and examines ways in which university libraries, the main proponents, have changed their approaches in response to their experience. The experience of Swinburne University of Technology, a partner in the Australian ARROW project, is drawn upon.     

Computational trust and reputation models for open multi-agent systems: a review

In open environments, agents depend on reputation and trust mechanisms to evaluate the behavior of potential partners. The scientific research in this field has considerably increased, and in fact, reputation and trust mechanisms have been already considered a key elements in the design of multi-agent systems. In this paper we provide a survey that, far from being exhaustive, intends to show the most representative models that currently exist in the literature. For this enterprise we consider several dimensions of analysis that appeared in three existing surveys, and provide new dimensions that can be complementary to the existing ones and that have not been treated directly. Moreover, besides showing the original classification that each one of the surveys provide, we also classify models that where not taken into account by the original surveys. The paper illustrates the proliferation in the past few years of models that follow a more cognitive approach, in which trust and reputation representation as mental attitudes is as important as the final values of trust and reputation. Furthermore, we provide an objective definition of trust, based on Castelfranchi’s idea that trust implies a decision to rely on someone.     

The Design and Effect of Child Restraint Systems in Vehicles

Abstract

This paper presents theoretical considerations and investigations concerning child restraint systems in vehicles. The major emphasis of the paper is on factors related to the handling qualities of different types of child restraint systems. Rearward facing seals were found to give the child the best protection while also offering good contact with and supervision of the child. Problems assumed lo exist in connection with this type of seat such as carsickness and the child's difficulty in seeing out were found to be rare, although general problems in connection with all types of restraints were observed and investigated. Rearward facing seats were found to be both practical and usable in Sweden according to questionnaire data from 1,575 parents collected in 1976. The ‘third generation’ of these seats is now being marketed in Sweden, and over 300 000 rearward facing seats have been sold to date.