Balancing task allocation in multi-robot systems using K-means clustering and auction based mechanisms

This paper aims to solve the balanced multi-robot task allocation problem. Multi-robot systems are becoming more and more significant in industrial, commercial and scientific applications. Effectively allocating tasks to multi-robots i.e. utilizing all robots in a cost effective manner becomes a tedious process. The current attempts made by the researchers concentrate only on minimizing the distance between the robots and the tasks, and not much importance is given to the balancing of work loads among robots. It is also found from the literature that the multi-robot system is analogous to Multiple Travelling Salesman Problem (MTSP). This paper attempts to develop mechanism to address the above two issues with objective of minimizing the distance travelled by ‘m’ robots and balancing the work load between ‘m’ robots equally. The proposed approach has two fold, first develops a mathematical model for balanced multi-robot task allocation problem, and secondly proposes a methodology to solve the model in three stages. Stage I groups the ‘N’ tasks into ‘n’ clusters of tasks using K-means clustering technique with the objective of minimizing the distance between the tasks, stage II calculates the travel cost of robot and clusters combination, stage III allocates the robot to the clusters in order to utilise all robot in a cost effective manner.     

Cognitive training via interactive television: drivers, barriers and potential users

This paper describes research to investigate the attitudinal and motivational factors that might facilitate or inhibit the uptake and use of cognitive training (CT) applications via interactive television (iTV) by both young and older people and to explore the profiles of potential users of such applications. A questionnaire was designed and distributed as part of the Vital Mind (VM) project. Data from a sample of 848 young and older people were collected and analysed using principal component analysis (PCA) and cluster analysis (CA). PCA of 41 attitude statements identified six components/factors. Three factors measured potential drivers to uptake and use of iTV-based CT applications (‘active wellbeing’, ‘health concern’ and ‘technophilia’) and two measured potential barriers (‘unprogressiveness’ and ‘telly-negativity’). A sixth factor (‘active sociability’) could act as either a driver or barrier, depending on how socially oriented are different CT applications. CA of the factors and age data revealed seven different profiles of potential users of CT through iTV. Three of the clusters were predominantly older (labelled Cultured-Conservatives, Digital-Immigrants and Telly-Fans), three were younger (labelled Healthy-Strivers, Digital-Natives and Net-Generation) and one was middle-aged (labelled Busy-Interactors). Reported media use and activity (mental, physical and social) were consistent with the attitude profiles of the clusters. The appeal of iTV-based CT was generally high, with Digital-Natives and Digital-Immigrants indicating the most interest. This research provides evidence for the key attitudinal dimensions predictive of likely adoption and use of iTV-based CT, and a refined understanding of target younger and older user markets.     

Exploring ‘Generation Y’ interaction qualities at home and at work

Information technology support of office work has increased rapidly in functionality, but new ways of interacting have evolved more slowly. This paper adds to the design research community’s notion of interaction quality by exploring these new ways of interacting and comparing them in the home and work contexts. We describe and analyze two interview studies conducted with office workers to consider how they perceive, experience and compare interaction qualities. Six interaction qualities (instant, expressive, playful, collaborative, responsive and flexible) were identified that together embody an interaction style that we have labeled ‘Generation Y.’ From learning and comparing these qualities, we found that personal and natural type of interactions were mostly experienced in the more private home context. Formal and subtle type of interactions were mostly experienced in the more public work context. We also found that the office workers scored the interaction qualities in their home context as richer than in their work context. This study resulted in a set of design guidelines, aiming to be used to implement the Generation Y interaction style in future office tools and applications. Designers and researchers will benefit from the result of this study from understanding rich interaction design in the work context.     

A density invariant approach to clustering

Organizing data into sensible groups is called as ‘data clustering.’ It is an open research problem in various scientific fields. Neither a universal solution nor an absolute strategy for its evaluation exists in the literature. In this context, through this paper, we make following three contributions: (1) A new method for finding ‘natural groupings’ or clusters in the data set is presented. For this, a new term ‘vicinity’ is coined. Vicinity captures the idea of density together with spatial distribution of data points in feature space. This new notion has a potential to separate various type of clusters. In summary, the approach presented here is non-convex admissive (i.e., convex hulls of the clusters found can intersect which is desirable for non-convex clusters), cluster proportion and omission admissive (i.e., duplicating a cluster arbitrary number of times or deleting a cluster does not alter other cluster’s boundaries), scale covariant, consistent (shrinking within cluster distances and enlarging inter-cluster distances does not affect the clustering results) but not rich (does not generates exhaustive partitions of the data) and density invariant. (2) Strategy for automatic detection of various tunable parameters in the proposed ‘Vicinity Based Cluster Detection’ (VBCD) algorithm is presented. (3) New internal evaluation index called ‘Space-Density Index’ (SDI) for the clustered results (by any method) is also presented. Experimental results reveal that VBCD captures the idea of ‘natural groupings’ better than the existing approaches. Also, SDI evaluation scheme provides a better judgment as compared to earlier internal cluster validity indices.

     

Natural,practical and social contexts of e‐learning: a critical realist account for learning and technology

Much of the research in educational technology with a primary concern over how technology enhances learning has been criticized as privileging the immediate learning settings over the other dimensions of learners’ social life and the wider social and economic contexts in which learning and technology are located. The ability to develop a rich understanding of learning and technology in various contexts requires careful use of theory that might enable ‘looking beyond learning’. To meet this need, this paper proposes the use of a critical realistic account of learning and technology, in particular Margaret Archer's ‘three orders of reality’ and ‘personal Identity’. Drawing on an empirical case study for illustration, the paper argues that such an approach offers a ‘way out’ to unpack the relationship between learning and technology through a deep exploration of the interrelationship between individual practices of learning, with or without technology, and the bigger picture of how learning intervenes in other dimensions of social life and how other contexts come into play in learning settings.     

Animating with style: defining expressive semantics of motion

Actions performed by a virtual character can be controlled with verbal commands such as ‘walk five steps forward’. Similar control of the motion style, meaning how the actions are performed, is complicated by the ambiguity of describing individual motions with phrases such as ‘aggressive walking’. In this paper, we present a method for controlling motion style with relative commands such as ‘do the same, but more sadly’. Based on acted example motions, comparative annotations, and a set of calculated motion features, relative styles can be defined as vectors in the feature space. We present a new method for creating these style vectors by finding out which features are essential for a style to be perceived and eliminating those that show only incidental correlations with the style. We show with a user study that our feature selection procedure is more accurate than earlier methods for creating style vectors, and that the style definitions generalize across different actors and annotators. We also present a tool enabling interactive control of parametric motion synthesis by verbal commands. As the control method is independent from the generation of motion, it can be applied to virtually any parametric synthesis method.     

Technology-push and communication-pull forces driving message-based coordination performance

This study adopts ‘push–pull’ concepts to address the effects of technology, communication and tasks on e-mail coordination, and to explore appropriate e-mail contexts in cooperative work. The perceived benefits of communication technology form a ‘push’ force. Two ‘pull’ forces include the desire to solve a cognitive gap caused by the communication context, and the desire to bridge the performance gap in allocating resources to tasks. The empirical findings confirm that ‘technology-push’ and ‘communication-pull’ forces are positively associated with e-mail coordination performance, showing the coexistence of rational and social influences, while the association between task and communication contexts indicates that the development of perceived information-sharing norms is context-dependent. Accordingly, this study concludes that appropriate information-sharing norms enable actors to create an active communication context for using e-mail in cooperative work.     

Barriers to e-commerce and competitive business models in developing countries: A case study

This paper integrates and extends research on e-commerce in the developing world. We use three categories of feedback systems–economic, sociopolitical and cognitive—to offer a simple model of e-commerce barriers in the developing world. We also examine characteristics of e-business models that can be successfully employed in developing countries. Then, we provide the case of an e-business model followed by a Nepal-based multiple international award winning online provider. This paper’s theoretical contribution is to explain the ‘hows’ and ‘whys’ of e-commerce in developing countries and to identify clear contexts and attendant mechanism.     

Human optimization with moving optima

Abstract

Earlier work had examined how humans optimize a two-variable function. This paper extends the study to optimization when the position of the optimum can change with time. Thirty student subjects performed a blind hill climbing task under two levels of display noise and three levels of movement of the optimum. Performance was studied using 13 measures, which were found to group into three factors, ‘deviation size’, ‘hits on target’ and ‘speed’. It was found that the movement of the optimum degraded performance once the general area of the optimum was reached. Display noise also degraded performance. Subjects with formal optimization training performed better on the ‘deviation size’ factor but had no advantage on ‘hits on target’ and ‘speed’ factors.     

Secondary school educators' perceptions and practices in handling cyberbullying among adolescents: A cluster analysis

School educators play an important role in cyberbullying management. Since scarce earlier research indicated low perceived competence of school educators in handling cyberbullying, more insight is needed in what determines their actions and how to improve these practices. This study assessed school educator practices, their perceptions and context factors from a behavior change theoretical framework, and investigated educator clusters related to this. An online survey was conducted among 451 secondary school educators (teachers, principals, school counselors). School educators mostly used recommended actions (i.e. conversations with pupils, enlisting professionals for support, parental involvement, providing supportive victim advice). Four educator clusters were identified: ‘referrers’ (65%), ‘disengaged’ educators (14%), ‘concerned’ educators (12%) and ‘use all means’ educators (9%). The first two clusters were less adept at handling cyberbullying and comprised mostly teachers, particularly indicating a need for training teachers. Our findings show a need for tailored educator training, e.g. by job position, gender, school size and grade. The behavior change theoretical framework can help target educators' particular needs.     

The Creation and Management of Cultural Clusters

This paper analyses two cultural clusters, the Westergasfabriek (WGF) in Amsterdam and the Witte de Withstraat (WdW) in Rotterdam, and evaluates their contrasting creative management strategies. The WGF has to date been fairly successful in creating an attractive mix of different cultural activities, based on the creative potential of the buildings on the site, its image as a cultural centre and the general atmosphere of creativity. The more ‘top–down’ approach of the Local Authority owned but commercially managed WFG has injected new commercial skills and investment into the cluster, and creates the conditions for innovation through managing the mix of creative functions. The WdW, on the other hand, takes a more ‘bottom–up’ approach to the problems of cultural management, and so far the participants have resisted the imposition of formal management. This may allow cultural and commercial functions to co–exist more easily, but, thus far, there seems to be less evidence of innovation.     

Analysis of critical factors for social games based on extended technology acceptance model: a DEMATEL approach

In recent years, social games such as ‘Farmville’ and ‘Pokémon Go’ have become a major game type in the gaming industry. This study examines the importance of different factors in social games using the Technology Acceptance Model (TAM) and DEMATEL. The result shows ‘social norm’ as the most important factor overall. It is also found that ‘pleasure’ and ‘sociability’ are the most important aspects in ‘perceived enjoyment’. Regarding key aspects in each factor, ‘flow experience’ is crucial in ‘perceived attractiveness’, ‘game fairness’ largely influential in ‘social norm’, and ‘reputation of platform and service provider’ a decisive aspect in ‘platform service and corporate image’. These findings and analyses are apt references for social game providers to improve their services.     

A reflexive analysis of ‘context’ in privacy research: Two case studies in HIV care

Privacy is a much discussed and politically charged topic in contemporary healthcare. Yet, studying the actual privacy practices of healthcare professionals and patients remains extremely challenging. In this paper we reflect on our experiences using qualitative methods in two projects on HIV care, the first researching internet use by a particular group of patients, and the second looking at issues of information technology integration in hospitals. Our aim in doing so is to highlight some of the opportunities and challenges involved in including an explicit focus on ‘context’ in qualitative privacy research in healthcare. We suggest that adopting a more reflexive approach to the way methods are used in relation to ‘context’ in privacy-related HCI research provides opportunities for understanding how different ‘privacy contexts’ are enacted in and through our research practices in different environments.     

A contextual analysis of Pascal programs

More than 120,000 lines of Pascal programs, written by graduate students and faculty members, have been statically analysed to provide a better understanding of how the language is ‘really’ used. The analysis was done within twelve distinct contexts to discover differences in usage patterns among the various contexts. For example, it was found that 47 per cent of the operands in arguments lists were constants. The results are displayed as tables of frequency counts which show how often each construct is used within a context. Also, we have compared our findings to the results from studies of other languages, such as FORTRAN, SAL and XPL.     

Syntactic word embedding based on dependency syntax and polysemous analysis

Most word embedding models have the following problems: (1) In the models based on bag-of-words contexts, the structural relations of sentences are completely neglected; (2) Each word uses a single embedding, which makes the model indiscriminative for polysemous words; (3) Word embedding easily tends to contextual structure similarity of sentences. To solve these problems, we propose an easy-to-use representation algorithm of syntactic word embedding (SWE). The main procedures are: (1) A polysemous tagging algorithm is used for polysemous representation by the latent Dirichlet allocation (LDA) algorithm; (2) Symbols ‘+’ and ‘?’ are adopted to indicate the directions of the dependency syntax; (3) Stopwords and their dependencies are deleted; (4) Dependency skip is applied to connect indirect dependencies; (5) Dependency-based contexts are inputted to a word2vec model. Experimental results show that our model generates desirable word embedding in similarity evaluation tasks. Besides, semantic and syntactic features can be captured from dependency-based syntactic contexts, exhibiting less topical and more syntactic similarity. We conclude that SWE outperforms single embedding learning models.     

Designing in between Local Government and the Public – Using Institutional Analysis in Interventions on Civic Infrastructures

Adapting and changing the systems and technologies involved in civic engagement with local government is among the key challenges of collaborative technologies for political participation. In such contexts, both existing sets of technologies and ingrained, often formalised practices, the ‘rules of the game’, constrain any opportunity for intervention. Additionally, ‘civic’ and expert groups with conflicting agendas and divergent demands on public choices assert their influence in these transformation programmes. The article argues that established methods in collaborative systems design have thus far overlooked the role of recurring actions involved in public participation as well as the formal rules and ingrained practices that construct them. Yet, such patterns present a valuable resource for design interventions. Thus, based on an institutional approach, the article outlines a methodology for requirement gathering by mapping the relations of actors, software and their use along identifiable action situations. The method called for a dialogue between socio-technical-spatial contexts of public service and specific actions taking place within it. Drawing on a case of organising civic engagement in urban planning, the article discusses how to find and trace existing practices across social settings, information technologies and material contexts where engagements take place. The approach underscores the existing institutional contexts in inspiring, opening and constraining the opportunities to support ‘civics’.     

The effect of skill level,external frame of reference and environmental changes on one-handed catching

Abstract

Two groups of subjects designated ‘good’ (n= 12) and ‘poor’ (n= 10) catchers on the basis of a task-specific criterion were required to catch, one-handed, balls projected from a ball-projection machine under eight different conditions. Four of these comprised the ‘environment illuminated’ conditions (full light; hand obscured by an opaque screen; a see-through screen and an external vertical reference frame in the field of view) and four others the ‘environment dark’ conditions (catching hand wearing a glove painted with luminescent paint and u. v. illuminated ball in an otherwise dark room; ball illuminated by u. v. light; luminescent hand and external luminescent vertical reference plus u. v. illuminated ball; u. v.-illuminated ball, plus luminescent vertical reference).

While clear and significant differences - as was to be expected from the selection criteria imposed - were shown between the groups of ‘good’ and ‘poor’ catchers for all three dependent variables-number of catches, spatial errors and temporal errors-it was demonstrated that, for both groups, degrading the environment, by reducing the information available, resulted in a significant performance decrement on the dependent variables ‘number of catches’ and ‘temporal errors’. ‘Poor’ catchers were also shown to make significantly more spatial errors than ‘good’ catchers. Whereas the latter finding confirms earlier findings reported in the literature, the significant effect on performance of degrading the environment -particularly with respect to temporal errors - is new. The finding is discussed in the framework of the use of ‘tau’ (time to contact) in making judgements about when to initiate the grasp response.     

An examination of the relationship between cycle training,cycle accidents,attitudes and cycling behaviour among children

Around 40% of 10–11-year-old children receive cycle training every year in the UK, but concern has been expressed over the efficacy of training courses. One argument is that accidents occur too infrequently to be a viable evaluative criterion, and attitudes and behaviour have been suggested as alternatives. A questionnaire that measured a number of variables including accidents, attitudes, and behaviour was completed by 336 participants from two schools in the London Borough of Bromley. At least one cycling injury had been sustained by 58.3% of respondents, requiring hospital treatment in 19.1% of cases. Girls reported fewer accidents than boys. No relationship between training and accidents was found. A principal components analysis (PCA) of the attitudes items produced a ‘safe attitudes’ factor. Girls displayed ‘safer’ attitudes, but there was no evidence that training produced safer attitudes. A PCA of the cycling behaviour scales produced two factors, ‘safe cycling’ and ‘showing off’. Safe cyclists who obeyed basic safety rules were less likely to sustain cycle injuries, but showing off was not related to accidents. Girls were less likely to show off, but the safe behaviour gender difference did not reach significance. Training did not relate to either factor.     

A combined algorithm for weighting the variables and clustering in the clustering problem

One problem in clustering (classification) analysis relates to whether or not the original variables should be transformed in some way before they are used by the clustering algorithm. More often than not, the original variables do require some transformation. The purpose of the transformation may be a desire to have more compact clusters in the space of the transformed variables, to take into account the different nature and/or units of the variables involved, to allow for the different or equal ‘importance’ of different variables, to minimize the number of variables used, etc. Among the linear transformations of variables we distinguish two groups - those which change only the scales of the variables (they are often called weighting procedures), and those which also rotate the space of variables (a good example would be the method of principal components⁽¹⁾). This paper addresses the former group of transformations.One strong reason for using the weighted variables (as opposed to their linear combinations) is that when using them one can interpret the results of the classification in terms of the original (physical) variables. Unfortunately, weighting the variables can result in ‘spoiling’ the compactness of the clusters in the space of the weighted variables if the weighting procedure being used ‘does not care’ about the results of clustering (in other words if the weighting is done prior to and independently of the clustering).A method of weighting the variables which is a part of the classification procedure and thus guarantees an improvement of the cluster clarity is suggested in this paper. The weights of variables and the clusters of objects produced by the algorithm correspond to a local minimum of some classification criterion. Because of this, the resultant weights can be interpreted as a measure of ‘importance’ of the variables for the classification purpose. These weights are compared with such popular weighting procedures as equal variance⁽⁶⁾ and Mahalanobis distance⁽⁷⁾ methods. Two examples of the performance of the algorithm are presented.