Decision support for “messy” problems

Problems that are non-quantitative and not bound to a narrow knowledge domain have been served unsatisfactorily by decision support and expert systems. Alternative techniques that address this type of problem are explained here using two key concepts: problem type dependent process support and domain related knowledge. Process support refers to the program steps and the data items useful in finding the solution. Domain related knowledge is knowledge drawn from a specific domain, yet through abstraction applicable to a wider range of problems. Results of preliminary empirical analyses suggest that both concepts are useful.     

Comments on “some results on pole-placement and reachability”

We present various comments on a question about systems over rings posed in a recent note by Sharma, proving that a ring R is pole assignable if and only if, for every reachable system (F, G), G contains a rank-one summand of the state space. We also provide a generalization to deal with dynamic feedback.     

Salience of public leaders’ “meaning making” in news coverage of a health crisis

Meaning making by leadership in a crisis is required to reduce uncertainty. We used analytic criteria for meaning making suggested by crisis management literature to investigate public leaders’ quotations in news coverage of a health crisis. The quotations were examined in terms of the five frame functions, which include offering a credible explanation of what happened, offering guidance, instilling hope, showing empathy, and suggesting that leaders are in control. The Middle East respiratory syndrome outbreak in South Korea was examined. As a result, the most salient frame function identified was displaying they are in control of the emergency, followed by offering guidance and explaining what happened. The salience of leaders’ meaning making disappeared in coverage by a liberal newspaper.     

A search space “cartography” for guiding graph coloring heuristics

We present a search space analysis and its application in improving local search algorithms for the graph coloring problem. Using a classical distance measure between colorings, we introduce the following clustering hypothesis: the high quality solutions are not randomly scattered in the search space, but rather grouped in clusters within spheres of specific diameter. We first provide intuitive evidence for this hypothesis by presenting a projection of a large set of local minima in the 3D space. An experimental confirmation is also presented: we introduce two algorithms that exploit the hypothesis by guiding an underlying Tabu Search (TS) process. The first algorithm (TS-Div) uses a learning process to guide the basic TS process toward as-yet-unvisited spheres. The second algorithm (TS-Int) makes deep investigations within a bounded region by organizing it as a tree-like structure of connected spheres. We experimentally demonstrate that if such a region contains a global optimum, TS-Int does not fail in eventually finding it. This pair of algorithms significantly outperforms the underlying basic TS algorithm; it can even improve some of the best-known solutions ever reported in the literature (e.g. for dsjc1000.9).     

Offline variants of the “lion and man” problem: —Some problems and techniques for measuring crowdedness and for safe path planning—

Consider the following safe path planning problem: Given a set of trajectories (paths) of k point robots with maximum unit speed in a bounded region over a (long) time interval [0,T], find another trajectory (if it exists) subject to the same maximum unit speed limit, that avoids (that is, stays at a safe distance of) each of the other k trajectories over the entire time interval. We call this variant the continuous model of the safe path planning problem. The discrete model of this problem is: Given a set of trajectories (paths) of k point robots in a graph over a (long) time interval 0,1,2,…,T, find a trajectory (path) for another robot, that avoids each of the other k at any time instant in the given time interval.We introduce the notions of the avoidance number of a region, and that of a graph, respectively, as the maximum number of trajectories which can be avoided in the region (respectively, graph). We give the first estimates on the avoidance number of the n×n grid G_n, and also devise an efficient algorithm for the corresponding safe path planning problem in arbitrary graphs. We then show that our estimates on the avoidance number of G_n can be extended for the avoidance number of a bounded (fat) region. In the final part of our paper, we consider other related offline questions, such as the maximum number of men problem and the spy problem.     

“ExTherm 2 ”: An interactive support package of experimental and computational thermodynamics

“ExTherm 2” shows clear advances over ExTHERM as presented in [J. Tomiska, CALPHAD 26 (2002) 143–154]: All three parts have been improved in powerfulness, comfort, and interactive work. Especially the module cM3_ is now designed for interactive evaluation by means of an overall best fit technique applicable on experimental data from calorimetric and vapor pressure measurements as well as from measurements on the electromotive force (emf) on all types of metal alloy. The new data bank module cM1_(ETD/ ExP/ PhD) is an easy-to-handle tool for interactive work in many applications in physical chemistry. The data bank ETD has been enlarged by a series of new molar mixing properties of all types of metal alloy systems, and two sub-modules are added: The first tool, ExP, makes extrapolating binary data to a high number of ternary systems of all types of metal alloy possible. And the second tool, PhD, is designed for simple interactive computations on binary phase diagrams, especially for education items.     

Author's reply: “A comment on optimal control of SISO continuous-time systems”

In the above-mentioned comment, the author points out a technical problem with the paper (Wang, Z. Q., & Sznaier, M. (1997). Automatica, 33(1), 85–90). As we show here, this technical problem can be easily solved. Moreover, it affects neither the main formulation nor the results, which remain valid.     

No-Longer-Foreign: Teaching an ML compiler to speak C “natively”

We present a new foreign-function interface for SML/NJ. It is based on the idea of data-level interoperability—the ability of ML programs to inspect as well as manipulate C data structures directly.The core component of this work is an encoding of the almost² complete C type system in ML types. The encoding makes extensive use of a “folklore” typing trick, taking advantage of ML's polymorphism, its type constructors, its abstraction mechanisms, and even functors. A small low-level component which deals with C struct and union declarations as well as program linkage is hidden from the programmer's eye by a simple program-generator tool that translates C declarations to corresponding ML glue code.     

Discursive Equality and Everyday Talk Online: The Impact of “Superparticipants”

Empirical studies of online debate almost universally observe a “dominant” minority of posters. Informed by theories of deliberative democracy, these are typically framed negatively—yet research into their impact on debate is scant. To address this, a typology of what we call super‐participation (super‐posters, agenda‐setters and facilitators) is developed and applied to the http://www.moneysavingexpert.com/ forum. Focusing on the first of these, we found 2,052 superposters (0.4%) contributing 47% of 25m+ posts. While superposters were quantitatively dominant, qualitative content analysis of the discursive practices of 25 superposters (n=40,044) found that most did not attempt to stop other users from posting (curbing) or attack them (flaming). In fact, in contradiction to the received wisdom, super‐posters discursively performed a range of positive roles.     

“StoryWeb”: A storytelling‐based knowledge‐sharing application among multiple stakeholders

The research objective of this paper is to develop a storytelling‐based knowledge‐sharing application that enables users to co‐create their own stories for both individuals and groups. To address this, a design science research methodology was applied for elucidating users' requirements. As empirical evidence, a case study was conducted on the children's book industry to synthesize a knowledge‐sharing design application named “StoryWeb”. Usability tests were conducted to reconfigure users' feedback and suggestions after two StoryWeb prototypes were developed. This study makes three main contributions. First, it empirically tests individual's or group's creativity and co‐creation by a view of knowledge sharing. Second, it methodologically applies a design thinking approach into a knowledge‐sharing study. Third, it also practically suggests feasible guidelines for the creativity and innovation research community on which features of storytelling‐based applications can be configured.     

H∞ identification of “soft” uncertainty models

The paper investigates the problem of identifying uncertainty models of causal, SISO, LTI, discrete-time, BIBO stable, unknown systems, using frequency domain measurements corrupted by Gaussian noise of known covariance. Additive uncertainty models are looked for, consisting of a nominal model and an additive dynamic perturbation accounting for the modeling error. The nominal model is chosen within a class of affinely parametrized models with transfer function of given (possibly low) order. An estimate of the parameters minimizing the H_∞ modeling error is obtained by minimizing an upper bound of the worst-case (with respect to the modeling error) second moment of the estimation error. Then, a bound in the frequency domain guaranteeing to include, with probability α, the frequency response error between the estimated nominal model and the unknown system is derived.     

Comment and Further Result on “Fault Detection and Isolation Method Based on H−/H∞ Unknown Input Observer Design in Finite Frequency Domain”

This paper considers the work entitled “Fault detection and isolation method based on H_?/H_∞ unknown input observer design in finite frequency domain”, published previously in the Asian Journal of Control. We point out that some design matrices in the above mentioned article have no effect on the design result. Furthermore, we show that the conditions proposed therein for H_∞ design are conservative and propose an improved design method.     

Extensions to “Output prediction under scarce data operation: control applications”

Albertos et al. (Automatica, 35 (1999) 1671–1681), proposed a simple and computationally cheap output estimation algorithm for systems where some output data is missing. In the original paper, a stability analysis of the algorithm is provided for the special case that every Nth sample of the output is observed. We here show how the stability can be analysed for arbitrary periodical missing data patterns.     

The identification of nonlinear models for process control using tailored “plant-friendly” input sequences

This paper considers certain practical aspects of the identification of nonlinear empirical models for chemical process dynamics. The primary focus is the identification of second-order Volterra models using input sequences that offer the following three advantages: (1) they are “plant friendly;” (2) they simplify the required computations; (3) they can emphasize certain model parameters over others. To provide a quantitative basis for discussing the first of these advantages, this paper defines a friendliness index f that relates to the number of changes that occur in the sequence. For convenience, this paper also considers an additional nonlinear model structure: the Volterra–Laguerre model. To illustrate the practical utility of the input sequences considered here, second-order Volterra and Volterra–Laguerre models are developed that approximate the dynamics of a first-principles model of methyl methacrylate polymerization.     

Beyond “bouncing back”: Towards an integral,capability‐based understanding of organizational resilience

Academic debates surrounding the notion of resilience still face dissent about definitions, contexts, and managerial implications. By summarizing recent literature on resilience, this paper reveals two dominating paradigms, which I label the Plan to Resist Approach and the Containing Crisis Approach. By pinpointing and challenging the underlying assumptions of both approaches, I elucidate their potential shortcomings. To overcome these limitations, I develop an integral, capability‐based concept of organizational resilience, which builds on a temporal perspective on crises. Thereby it highlights the importance of enacting different yet specific capabilities at different phases of crises. This concept allows integrating the insights of the reviewed literature and sheds light on the recovery phase as being a so far neglected aspect in resilience research.     

An interactional view of social presence: Making the virtual other “real”

In IS research, social presence is generally defined as the perceived capacity of a communication medium to convey contextual cues normally available in face‐to‐face settings. However, theorizing social presence as a property of the technology has been challenged for decades. The objective of this paper is to develop a more contemporary, interactional view of social presence. To this end, this paper develops a new conceptualization of how participants form the sense that each other is present. We characterize the development of this sense as a skilful accomplishment that entails interactants' joint construction of each other as “real.” Viewing social presence as contingent on social practice, we seek to answer the following research question: “How is social presence accomplished in virtual environments?” To explicate how virtual others are perceived as becoming socially present, that is, emotionally and psychologically “real” to someone interacting with them, we draw from Goffman's work, particularly his concepts of involvement and involvement obligation. Detailing two examples of social interaction in the virtual world Second Life, our analysis highlights the key role that this moral obligation, intrinsic to everyday social interaction, plays in virtual others becoming perceived as psychoemotionally “there.” By outlining a model of how the sense of a virtual other as “real” is produced in and through social interaction, our work contributes a sociological perspective to the construct of social presence and underscores some of the material and social conditions necessary for users to perceive virtual others as present.     

“Highly Recommended!” The Content Characteristics and Perceived Usefulness of Online Consumer Reviews

The aim of the present study was to gain a better understanding of the content characteristics that make online consumer reviews a useful source of consumer information. To this end, we content analyzed reviews of experience and search products posted on Amazon.com (N = 400). The insights derived from this content analysis were linked with the proportion of ‘useful’ votes that reviews received from fellow consumers. The results show that content characteristics are paramount to understanding the perceived usefulness of reviews. Specifically, argumentation (density and diversity) served as a significant predictor of perceived usefulness, as did review valence although this latter effect was contingent on the type of product (search or experience) being evaluated in reviews. The presence of expertise claims appeared to be weakly related to the perceived usefulness of reviews. The broader theoretical, methodological and practical implications of these findings are discussed.     

The “Nasty Effect:” Online Incivility and Risk Perceptions of Emerging Technologies

Uncivil discourse is a growing concern in American rhetoric, and this trend has expanded beyond traditional media to online sources, such as audience comments. Using an experiment given to a sample representative of the U.S. population, we examine the effects online incivility on perceptions toward a particular issue—namely, an emerging technology, nanotechnology. We found that exposure to uncivil blog comments can polarize risk perceptions of nanotechnology along the lines of religiosity and issue support.