Which sort orders are interesting?

Sort orders play an important role in query evaluation. Algorithms that rely on sorting are widely used to implement joins, grouping, duplicate elimination and other set operations. The notion of interesting orders has allowed query optimizers to consider plans that could be locally sub-optimal, but produce ordered output beneficial for other operators, and thus be part of a globally optimal plan. However, the number of interesting orders for most operators is factorial in the number of attributes involved. Optimizer implementations use heuristics to prune the number of interesting orders, but the quality of the heuristics is unclear. Increasingly complex decision support queries and increasing use of query-covering indices, which provide multiple alternative sort orders for relations, motivate us to better address the problem of choosing interesting orders. We show that even a simplified version of the problem is NP-hard and provide a 1/2-benefit approximation algorithm for a special case of the problem. We then present principled heuristics for the general case of choosing interesting orders. We have implemented the proposed techniques in a Volcano-style cost-based optimizer, and our performance study shows significant improvements in estimated cost. We also executed our plans on a widely used commercial database system, and on PostgreSQL, and found that actual execution times for our plans were significantly better than for plans generated by those systems in several cases.     

Effects of form and motion on judgments of social robots׳ animacy,likability, trustworthiness and unpleasantness

One of robot designers׳ main goals is to make robots as sociable as possible. Aside from improving robots׳ actual social functions, a great deal of effort is devoted to making them appear lifelike. This is often achieved by endowing the robot with an anthropomorphic body. However, psychological research on the perception of animacy suggests another crucial factor that might also contribute to attributions of animacy: movement characteristics. In the current study, we investigated how the combination of bodily appearance and movement characteristics of a robot can alter people׳s attributions of animacy, likability, trustworthiness, and unpleasantness. Participants played games of Tic-Tac-Toe against a robot which (1) either possessed a human form or did not, and (2) either exhibited smooth, lifelike movement or did not. Naturalistic motion was judged to be more animate than mechanical motion, but only when the robot resembled a human form. Naturalistic motion improved likeability regardless of the robot׳s appearance. Finally, a robot with a human form was rated as more disturbing when it moved naturalistically. Robot designers should be aware that movement characteristics play an important role in promoting robots׳ apparent animacy.     

Uncertainty,measurement and thermodynamics of information†

In this paper we speculate on the existence of a notion of information and an information-theoretic structure that could be generally applicable in systems analysis. From basic principles and by physical analogies we hypothesize on some qualitative and quantitative relationships between entropy and information.

Information and entropy are here regarded as the basic, or primitive, system variables, conceptually interrelated in a manner which differs from the traditional ideas on information vis-a-vis entropy. In a quasi-physical manner it is proposed that information be considered as the one intensity and entropy as the one extensity that span the whole physical world. It is then possible to define a conserved quantity, termed informational power, relating information to entropy flow.

The above ideas are then generally applied to systems in which the act of measurement appreciably affects the system itself. This can introduce an aspect of uncertainty to large scale systems modelling similar to that occurring in particle physics. The central notions in this paper could provide a mechanism by means of which such aspects could be structurally accommodated in a model.     

Specification, Refinement and Verification of Concurrent Systems—An Integration of Object-Z and CSP

This paper presents a method of formally specifying, refining and verifying concurrent systems which uses the object-oriented state-based specification language Object-Z together with the process algebra CSP. Object-Z provides a convenient way of modelling complex data structures needed to define the component processes of such systems, and CSP enables the concise specification of process interactions. The basis of the integration is a semantics of Object-Z classes identical to that of CSP processes. This allows classes specified in Object-Z to be used directly within the CSP part of the specification.In addition to specification, we also discuss refinement and verification in this model. The common semantic basis enables a unified method of refinement to be used, based upon CSP refinement. To enable state-based techniques to be used for the Object-Z components of a specification we develop state-based refinement relations which are sound and complete with respect to CSP refinement. In addition, a verification method for static and dynamic properties is presented. The method allows us to verify properties of the CSP system specification in terms of its component Object-Z classes by using the laws of the CSP operators together with the logic for Object-Z.     

Brain–computer interfaces and dualism: a problem of brain,mind, and body

The brain–computer interface (BCI) has made remarkable progress in the bridging the divide between the brain and the external environment to assist persons with severe disabilities caused by brain impairments. There is also continuing philosophical interest in BCIs which emerges from thoughtful reflection on computers, machines, and artificial intelligence. This article seeks to apply BCI perspectives to examine, challenge, and work towards a possible resolution to a persistent problem in the mind–body relationship, namely dualism. The original humanitarian goals of BCIs and the technological inventiveness result in BCIs being surprisingly useful. We begin from the neurologically impaired person, the problems encountered, and some pioneering responses from computers and machines. Secondly, the interface of mind and brain is explored via two points of clarification: direct and indirect BCIs, and the nature of thoughts. Thirdly, dualism is beset by mind–body interaction difficulties and is further questioned by the phenomena of intentions, interactions, and technology. Fourthly, animal minds and robots are explored in BCI settings again with relevance for dualism. After a brief look at other BCIs, we conclude by outlining a future BCI philosophy of brain and mind, which might appear ominous and could be possible.     

Do hypercubes sort faster than tree machines?

We develop a balanced, parallel quicksort algorithm for a hypercube and compare it with a similar algorithm for a binary tree machine. The performance of the hypercube algorithm is measured on a Computing Surface.     

Numerical modelling of transport,dispersion, and deposition — validation against ETEX-1, ETEX-2 and Chernobyl

A comprehensive, high-resolution, 3-dimensional tracer model, DREAM, has been developed for studying transport, dispersion, and deposition of air pollution caused by a single but very strong source. The model is based on a combination of a Lagrangian short-scale puff model and an Eulerian long-range transport model. The meteorological meso-scale model MM5V1 is used as a driver for the transport model. The tracer model and the numerical implementation of the model is described in this paper. The Eulerian transport model has been splitted into different submodels. The advantages of treating the different physical processes on different scales by using different numerical algorithms will be discussed. The model has been run and validated against measurements from the two ETEX releases (the European Tracer EXperiment) and the Chernobyl accident. 2-D and 3-D visualizations together with some comparisons of model results with measurements will be presented and discussed. The combined model is able to reproduce dosages within a factor of 2–3 in the worst case and arrival times within 2–3 h, compared to measurements from ETEX-1 and Chernobyl. This is within the currently achievable limits of accuracy in long-range dispersion modelling, according to the ETEX-1 experiment.     

Symbiosis and synergy? scenarios,task analysis and reuse of HCI knowledge

This paper follows the scenarios and task models debate by reviewing the contributions of task modelling and scenario based approaches from a cognitive perspective. A framework of cognitive affordances is introduced to discuss the merits and limitations of each approach. An extension of the modelling theme, generic task models, is proposed to augment the contribution of knowledge reuse to the design process. The paper concludes by discussing how scenario based design might complement task analysis and reuse of task based knowledge.     

On the notions of normality, locality, and operational stability in ADRC

Treating plant dynamics as an ideal integrator chain disturbed by the total disturbance is the hallmark of active disturbance rejection control (ADRC). To interpret its effectiveness and success, to explain why so many vastly different dynamic systems can be treated in this manner, and to answer why a detailed, accurate, and global mathematical model is unnecessary, is the target of this paper. Driven by a motivating example, the notions of normality and locality are introduced. Normality shows that, in ADRC, the plant is normalized to an integrator chain, which is called local nominal model and locally describes the plant’s frequency response in the neighborhood of the expected gain crossover frequency. Locality interprets why ADRC can design the controller only with the local information of the plant. With normality and locality, ADRC can be effective and robust, and obtain operational stability discussed by T. S. Tsien. Then viewing proportional-integral-derivative (PID) control as a low-frequency approximation of second-order linear ADRC, the above results are extended to PID control. A controller design framework is proposed to obtain the controller in three steps: (1) choose an integrator chain as the local nominal model of the plant; (2) select a controller family corresponding to the local nominal model; and (3) tune the controller to guarantee the gain crossover frequency specification. The second-order linear ADRC and the PID control are two special cases of the framework.     

Area,Curve Complexity,and Crossing Resolution of Non-Planar Graph Drawings

In this paper we study non-planar drawings of graphs, and study trade-offs between the crossing resolution (i.e., the minimum angle formed by two crossing segments), the curve complexity (i.e., maximum number of bends per edge), the total number of bends, and the area.     

Drivers’ attitudes,preference, and acceptance of in-vehicle anger intervention systems and their relationships to demographic and personality characteristics

This research conducted focus group interviews and a questionnaire survey to investigate the potential demand of drivers for anger intervention systems (AISs) and explore the effects of demographic factors and personality traits on the preference and attitudes toward AISs. Results indicate that drivers prefer auditory intervention over tactile and visual interventions. Moreover, they favor emotion recording features but also have negative attitudes about accuracy and system security. In addition, age and some personality traits (i.e., types of driving anger and categories of driving anger expressions) play an important role in predicting the preference of intervention modalities or attitudes toward AISs and provide a new perspective on designing customized intervention systems. The outcome of this research provides practical implications regarding the design of in-vehicle anger intervention systems for the automotive industry to reduce drivers’ anger and improve driving safety.     

Joining the blunt and the pointy end of the spear: towards a common framework of joint action,human–machine cooperation,cooperative guidance and control,shared, traded and supervisory control

To introduce this special issue of shared and cooperative control, we will look into history of tools in cooperation between humans and aim to unify the plethora of related concepts and definitions that have been proposed in recent years, such as shared control, human–machine cooperation and cooperative guidance and control. Concretely, we provide definitions to relate these concepts and sketch a unifying framework of shared and cooperative control that sees the different concepts as different perspectives or foci on a common design space of shared intentionality, control and cooperation between humans and machines. One working hypothesis which the article explores is that shared control can be understood as cooperation at the control layer, while human–machine cooperation can include shared control, but can also extend towards cooperation at higher layers, e.g., of guidance and navigation, of maneuvers and goals. The relationship between shared control and human–machine cooperation is compared to the relationship between the sharp, pointy tip and the (blunt) shaft of a spear. Shared control is where cooperation comes sharply into effect at the control layer, but to be truly effective it should be supported by cooperation on all layers beyond the operational layer, e.g., on the tactical and strategic layer. A fourth layer addresses the meta-communication about the cooperation and supports the other three layers in a traversal way.

     

Modelling,identification and control of sugar evaporation – theoretical design and experimental evaluation

This paper discusses the problem of controlling a multiple-stage industrial evaporator in a sugar factory. The control objectives are: syrup should have a sucrose concentration of 72%, the evaporator should produce the required amount of steam, and the steam consumption should be as low as possible. Achieving these objectives is difficult, due to the following plant features: strong disturbances, large time delays and many constraints. The control problem is solved by developing a physical model which is used as benchmark; then, a parametric identification is performed to obtain a control model. Finally, a successful real-time application of a multivariable GPC controller is presented.     

Driving comfort,enjoyment and acceptance of automated driving – effects of drivers’ age and driving style familiarity

Automated driving has the potential to improve the safety and efficiency of future traffic and to extend elderly peoples’ driving life, provided it is perceived as comfortable and joyful and is accepted by drivers. Driving comfort could be enhanced by familiar automated driving styles based on drivers’ manual driving styles. In a two-stage driving simulator study, effects of driving automation and driving style familiarity on driving comfort, enjoyment and system acceptance were examined. Twenty younger and 20 older drivers performed a manual and four automated drives of different driving style familiarity. Acceptance, comfort and enjoyment were assessed after driving with standardised questionnaires, discomfort during driving via handset control. Automation increased both age groups’ comfort, but decreased younger drivers’ enjoyment. Younger drivers showed higher comfort, enjoyment and acceptance with familiar automated driving styles, whereas older drivers preferred unfamiliar, automated driving styles tending to be faster than their age-affected manual driving styles.

Practitioner Summary: Automated driving needs to be comfortable and enjoyable to be accepted by drivers, which could be enhanced by driving style individualisation. This approach was evaluated in a two-stage driving simulator study for different age groups. Younger drivers preferred familiar driving styles, whereas older drivers preferred driving styles unaffected by age.     

The evolution of sentiment analysis—A review of research topics,venues, and top cited papers

Sentiment analysis is one of the fastest growing research areas in computer science, making it challenging to keep track of all the activities in the area. We present a computer-assisted literature review, where we utilize both text mining and qualitative coding, and analyze 6996 papers from Scopus. We find that the roots of sentiment analysis are in the studies on public opinion analysis at the beginning of 20th century and in the text subjectivity analysis performed by the computational linguistics community in 1990’s. However, the outbreak of computer-based sentiment analysis only occurred with the availability of subjective texts on the Web. Consequently, 99% of the papers have been published after 2004. Sentiment analysis papers are scattered to multiple publication venues, and the combined number of papers in the top-15 venues only represent ca. 30% of the papers in total. We present the top-20 cited papers from Google Scholar and Scopus and a taxonomy of research topics. In recent years, sentiment analysis has shifted from analyzing online product reviews to social media texts from Twitter and Facebook. Many topics beyond product reviews like stock markets, elections, disasters, medicine, software engineering and cyberbullying extend the utilization of sentiment analysis.     

Reinforcement or Displacement? The Reciprocity of FtF,IM, and SNS Communication and Their Effects on Loneliness and Life Satisfaction

Does communication on social network sites (SNSs) or instant messengers (IMs) reinforce or displace face‐to‐face (FtF) communication, and how do the 3 channels affect loneliness and life satisfaction? Using cross‐lagged structural equation modeling in a longitudinal and representative sample from Germany, we found that SNS communication increased both FtF and IM communication 6 months later. Likewise, IM communication at T1 increased SNS communication at T2. FtF, SNS, and IM communication did not affect loneliness, and FtF and IM communication did not change life satisfaction. However, communication on SNSs slightly increased life satisfaction. Thus, the data indicated that conversing via SNSs and IM has a mainly reinforcing effect and that communicating via SNSs can enhance life satisfaction several months later.     

A New Characterization of NP, P, and PSPACE with Accepting Hybrid Networks of Evolutionary Processors

We consider three complexity classes defined on Accepting Hybrid Networks of Evolutionary Processors (AHNEP) and compare them with the classical complexity classes defined on the standard computing model of Turing machine. By definition, AHNEPs are deterministic. We prove that the classical complexity class NP equals the family of languages decided by AHNEPs in polynomial time. A language is in P if and only if it is decided by an AHNEP in polynomial time and space. We also show that PSPACE equals the family of languages decided by AHNEPs in polynomial length.     

Hybrid model of bioresourses’ dynamics: Equilibrium,cycle, and transitional chaos

This article covers the development of nonlinear models of the dynamics of biological resources and their study using computer systems. The generalization showed that a number of non-linear effects in the dynamics of many population models are linked with biologically interpretable development criteria. The formalization of the theoretically proved dependencies of the populations’ reproduction led to the development of three new mathematical models. The first model corresponds to the dynamics of laboratory populations. The two other models are implemented in a computing environment using hybrid time and a special tuples structure. The computer modeling allowed establishing qualitatively different nonlinear effects for the three dynamical systems. The goal of developing new models is the analysis of scenarios of commercial fish populations’ degradation in the presence of important changes in their life cycles.