71 research outputs found

    Parallel genetic approach for routing optimization in large ad hoc networks

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    This article presents a new approach of integrating parallelism into the genetic algorithm (GA), to solve the problem of routing in a large ad hoc network, the goal is to find the shortest path routing. Firstly, we fix the source and destination, and we use the variable-length chromosomes (routes) and their genes (nodes), in our work we have answered the following question: what is the better solution to find the shortest path: the sequential or parallel method?. All modern systems support simultaneous processes and threads, processes are instances of programs that generally run independently, for example, if you start a program, the operating system spawns a new process that runs parallel elements to other programs, within these processes, we can use threads to execute code simultaneously. Therefore, we can make the most of the available central processing unit (CPU) cores. Furthermore, the obtained results showed that our algorithm gives a much better quality of solutions. Thereafter, we propose an example of a network with 40 nodes, to study the difference between the sequential and parallel methods, then we increased the number of sensors to 100 nodes, to solve the problem of the shortest path in a large ad hoc network

    To boardrooms and sustainability: the changing nature of segmentation

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    Market segmentation is the process by which customers in markets with some heterogeneity are grouped into smaller homogeneous segments of more ‘similar’ customers. A market segment is a group of individuals, groups or organisations sharing similar characteristics and buying behaviour that cause them to have relatively similar needs and purchasing behaviour. Segmentation is not a new concept: for six decades marketers have, in various guises, sought to break-down a market into sub-groups of users, each sharing common needs, buying behavior and marketing requirements. However, this approach to target market strategy development has been rejuvenated in the past few years. Various reasons account for this upsurge in the usage of segmentation, examination of which forms the focus of this white paper. Ready access to data enables faster creation of a segmentation and the testing of propositions to take to market. ‘Big data’ has made the re-thinking of target market segments and value propositions inevitable, desirable, faster and more flexible. The resulting information has presented companies with more topical and consumer-generated insights than ever before. However, many marketers, analytics directors and leadership teams feel over-whelmed by the sheer quantity and immediacy of such data. Analytical prowess in consultants and inside client organisations has benefited from a stepchange, using new heuristics and faster computing power, more topical data and stronger market insights. The approach to segmentation today is much smarter and has stretched well away from the days of limited data explored only with cluster analysis. The coverage and wealth of the solutions are unimaginable when compared to the practices of a few years ago. Then, typically between only six to ten segments were forced into segmentation solutions, so that an organisation could cater for these macro segments operationally as well as understand them intellectually. Now there is the advent of what is commonly recognised as micro segmentation, where the complexity of business operations and customer management requires highly granular thinking. In support of this development, traditional agency/consultancy roles have transitioned into in-house business teams led by data, campaign and business change planners. The challenge has shifted from developing a granular segmentation solution that describes all customers and prospects, into one of enabling an organisation to react to the granularity of the solution, deploying its resources to permit controlled and consistent one-to-one interaction within segments. So whilst the cost of delivering and maintaining the solution has reduced with technology advances, a new set of systems, costs and skills in channel and execution management is required to deliver on this promise. These new capabilities range from rich feature creative and content management solutions, tailored copy design and deployment tools, through to instant messaging middleware solutions that initiate multi-streams of activity in a variety of analytical engines and operational systems. Companies have recruited analytics and insight teams, often headed by senior personnel, such as an Insight Manager or Analytics Director. Indeed, the situations-vacant adverts for such personnel out-weigh posts for brand and marketing managers. Far more companies possess the in-house expertise necessary to help with segmentation analysis. Some organisations are also seeking to monetise one of the most regularly under-used latent business assets… data. Developing the capability and culture to bring data together from all corners of a business, the open market, commercial sources and business partners, is a step-change, often requiring a Chief Data Officer. This emerging role has also driven the professionalism of data exploration, using more varied and sophisticated statistical techniques. CEOs, CFOs and COOs increasingly are the sponsor of segmentation projects as well as the users of the resulting outputs, rather than CMOs. CEOs because recession has forced re-engineering of value propositions and the need to look after core customers; CFOs because segmentation leads to better and more prudent allocation of resources – especially NPD and marketing – around the most important sub-sets of a market; COOs because they need to better look after key customers and improve their satisfaction in service delivery. More and more it is recognised that with a new segmentation comes organisational realignment and change, so most business functions now have an interest in a segmentation project, not only the marketers. Largely as a result of the digital era and the growth of analytics, directors and company leadership teams are becoming used to receiving more extensive market intelligence and quickly updated customer insight, so leading to faster responses to market changes, customer issues, competitor moves and their own performance. This refreshing of insight and a leadership team’s reaction to this intelligence often result in there being more frequent modification of a target market strategy and segmentation decisions. So many projects set up to consider multi-channel strategy and offerings; digital marketing; customer relationship management; brand strategies; new product and service development; the re-thinking of value propositions, and so forth, now routinely commence with a segmentation piece in order to frame the ongoing work. Most organisations have deployed CRM systems and harnessed associated customer data. CRM first requires clarity in segment priorities. The insights from a CRM system help inform the segmentation agenda and steer how they engage with their important customers or prospects. The growth of CRM and its ensuing data have assisted the ongoing deployment of segmentation. One of the biggest changes for segmentation is the extent to which it is now deployed by practitioners in the public and not-for-profit sectors, who are harnessing what is termed social marketing, in order to develop and to execute more shrewdly their targeting, campaigns and messaging. For Marketing per se, the interest in the marketing toolkit from non-profit organisations, has been big news in recent years. At the very heart of the concept of social marketing is the market segmentation process. The extreme rise in the threat to security from global unrest, terrorism and crime has focused the minds of governments, security chiefs and their advisors. As a result, significant resources, intellectual capability, computing and data management have been brought to bear on the problem. The core of this work is the importance of identifying and profiling threats and so mitigating risk. In practice, much of this security and surveillance work harnesses the tools developed for market segmentation and the profiling of different consumer behaviours. This white paper presents the findings from interviews with leading exponents of segmentation and also the insights from a recent study of marketing practitioners relating to their current imperatives and foci. More extensive views of some of these ‘leading lights’ have been sought and are included here in order to showcase the latest developments and to help explain both the ongoing surge of segmentation and the issues under-pinning its practice. The principal trends and developments are thereby presented and discussed in this paper

    Constraint-based navigation for safe, shared control of ground vehicles

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 138-147).Human error in machine operation is common and costly. This thesis introduces, develops, and experimentally demonstrates a new paradigm for shared-adaptive control of human-machine systems that mitigates the effects of human error without removing humans from the control loop. Motivated by observed human proclivity toward navigation in fields of safe travel rather than along specific trajectories, the planning and control framework developed in this thesis is rooted in the design and enforcement of constraints rather than the more traditional use of reference paths. Two constraint-planning methods are introduced. The first uses a constrained Delaunay triangulation of the environment to identify, cumulatively evaluate, and succinctly circumscribe the paths belonging to a particular homotopy with a set of semi autonomously enforceable constraints on the vehicle's position. The second identifies a desired homotopy by planning - and then laterally expanding - the optimal path that traverses it. Simulated results show both of these constraint-planning methods capable of improving the performance of one or multiple agents traversing an environment with obstacles. A method for predicting the threat posed to the vehicle given the current driver action, present state of the environment, and modeled vehicle dynamics is also presented. This threat assessment method, and the shared control approach it facilitates, are shown in simulation to prevent constraint violation or vehicular loss of control with minimal control intervention. Visual and haptic driver feedback mechanisms facilitated by this constraint-based control and threat-based intervention are also introduced. Finally, a large-scale, repeated measures study is presented to evaluate this control framework's effect on the performance, confidence, and cognitive workload of 20 drivers teleoperating an unmanned ground vehicle through an outdoor obstacle course. In 1,200 trials, the constraint-based framework developed in this thesis is shown to increase vehicle velocity by 26% while reducing the occurrence of collisions by 78%, improving driver reaction time to a secondary task by 8.7%, and increasing overall user confidence and sense of control by 44% and 12%, respectively. These performance improvements were realized with the autonomous controller usurping less than 43% of available vehicle control authority, on average.by Sterling J. Anderson.Ph.D

    User interfaces in space science instrumentation

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    This thesis examines user interaction with instrumentation in the specific context of space science. It gathers together existing practice in machine interfaces with a look at potential future usage and recommends a new approach to space science projects with the intention of maximising their science return. It first takes a historical perspective on user interfaces and ways of defining and measuring the science return of a space instrument. Choices of research methodology are considered. Implementation details such as the concepts of usability, mental models, affordance and presentation of information are described, and examples of existing interfaces in space science are given. A set of parameters for use in analysing and synthesizing a user interface is derived by using a set of case studies of diverse failures and from previous work. A general space science user analysis is made by looking at typical practice, and an interview plus persona technique is used to group users with interface designs. An examination is made of designs in the field of astronomical instrumentation interfaces, showing the evolution of current concepts and including ideas capable of sustaining progress in the future. The parameters developed earlier are then tested against several established interfaces in the space science context to give a degree of confidence in their use. The concept of a simulator that is used to guide the development of an instrument over the whole lifecycle is described, and the idea is proposed that better instrumentation would result from more efficient use of the resources available. The previous ideas in this thesis are then brought together to describe a proposed new approach to a typical development programme, with an emphasis on user interaction. The conclusion shows that there is significant room for improvement in the science return from space instrumentation by attention to the user interface

    Towards inclusive GIS in the Congo Basin: an exploration of digital map creation and an evaluation of map understanding by non-literate hunter-gatherers

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    Sustainable and socially just natural resource management is one of the fundamental development challenges humanity is facing today. Communities living in remote areas possess unique insights about their natural resources. While this knowledge is critical to climate change, it is difficult for them to engage in environmental protection. Geographic Information Science (GIS) plays a central role in resource management, as it is utilised in spatial decision making processes. However, the literature argues that its use is too challenging for marginalised communities. Working with indigenous hunter-gatherers in the Congo Basin without prior exposure to technology or maps, this research moves towards enabling them to become active stakeholders in decision making so that they understand how to capture environmental knowledge and gain power through ownership. (Participatory) GIS, Human Computer Interaction, Action Research and Citizen Science concepts are adapted to the local context to address the lack of mapping of these areas, and the increased understanding of if and how digital, high resolution orthographic maps incorporated in digital mapping tools can be understood by people with no prior exposure to maps and technology. Different set-ups of low-cost Unmanned Aerial Vehicles and consumer grade cameras were tested and evaluated for suitability to generate high-resolution maps in-situ for previously unmapped and disconnected contexts. Applying a computer log analysis approach to overcome local obstacles, three experiments were carried out to test whether the resulting aerial orthophotos are understood as a representation of familiar geographical landscapes. For each of the experiments, a bespoke app functioning without an internet connection was developed. The research shows that the majority of the 136 participants could find as well as edit known features on the map and all participating groups were able to utilise a map for a Treasure Hunt game. Additionally, a number of methodological amendments are proposed to allow standardised research methods to be applied in a context where usability experiments are significantly challenged

    Gendered systemic analysis : systems thinking and gender equality in international development

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    Systemic intervention (Midgley, 2000) and Feminist Systems Thinking (Stephens, 2013a), both branches of Critical Systems Thinking, have been used widely to improve social and organisational systems. According to Midgley (2000), a systemic intervention can be defined as a “…purposeful action by an agent to create change” (113, emphasis original). Building on Midgley’s work, Stephens (2013a) created a non-hierarchical “… framework for feminist systems thinking, as a set of five principles that provide common sense guidelines for applied research and social action…” (8, emaphsis added). Presently, the small amount of gendered systemic research is troubling in a world where no country has achieved gender equality. The purpose of this research is to conduct a participatory systemic intervention working in partnership with a U.S. non-governmental agency in Washington D.C. in the United States, and Nicaragua in Central America, I conducted a feminist systemic intervention in an international development organisation. This study found that a more structured systemic intervention method, currently named Gendered Systemic Analysis, was needed to support stakeholders in identifying potential improvements in their businesses: previous work on Feminist Systems Thinking left too much of a gap between theory and practice. In this research, I follow Midgley’s (2011:11-12) use of ‘method’ as: “as a set of techniques operated in a sequence (or sometimes iteratively) to achieve a given purpose. GSA uses a boundary critique process, which concentrates attention on gender, nature and voices from the margin as a means to create social change. The contribution of this research deepened the understanding of how to empower individuals and groups to engage with systemic thinking and contextualise its theoretical and methodological underpinnings into a local knowledge generating systems leading to more sustainable change

    An evaluation framework for virtual reality safety training systems in the South African Mining Industry

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    The mining industry in South Africa contributes significantly to the national economy. Despite stringent safety legislation, mining accidents cause numerous fatalities and injuries. Inadequate or insufficient training is often cited as a root cause of accidents. Conventional class-based safety training has not reduced the incidence of accidents significantly. By contrast, virtual reality training tools can provide simulated exposure to real-world working conditions without the associated risks. This study describes the application of design-based research (DBR) in the design and development of two desktop virtual reality (VR) systems for safety training in the South African mining industry. The results of a usability context analysis were applied in the design of a VR prototype on generic hazards recognition and rectification, which was used and evaluated at South Africa‘s largest platinum mine site. A case study was conducted to investigate the causes and occurrences of falls of ground, which resulted in the design and development of a second VR prototype focusing on identifying and addressing underground geological conditions. DBR was also used in the generation of an evaluation framework for evaluating VR training systems, namely the Desktop VR Evaluation Framework (DEVREF), which is the major deliverable of the research. DEVREF can make a major contribution to the domain of e-training in mines and is transferable and customisable beyond its initial application. The process flow of the research thus moved beyond merely providing a solution to a complex real-world problem and became a classic DBR study with dual outcomes, namely a practical real-world solution in the form of two VR training systems and a theoretical contribution in the form of the DEVREF evaluation framework. DEVREF evaluates the design of desktop VR training systems in the categories of instructional design, usability, VR systems design, and context-specific criteria for mining. The use of DEVREF is demonstrated by reporting the application of its criteria in evaluating the two VR training systems. Heuristic evaluation, end-user surveys, and interviews were used as evaluation methods. A third contribution is methodological, in that this work proposes a new DBR process model and an interaction design lifecycle model suitable for VR training systems.ComputingD. Phil. (Information Systems

    Augmented Reality in Chemistry Higher Education

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    Augmented reality (AR) has the capacity to afford virtual experiences that obviate the reliance on using two-dimensional representations of three-dimensional phenomena for teaching chemistry higher education, in addition to positioning students as the protagonists of the learning experience. Thus, the subsequent blending of constructivist pedagogical approaches and AR technology is logical, with this paradigm having enormous methodological potential. Using a combination of quantitative and qualitative instruments, this research project explored the cognitive and affective impacts of engagement with four developed educational interventions, supported using ChemFord, a developed AR application. Firstly, an AR-supported educational escape activity, based on topics of inorganic stereochemistry was constructed. Reported measures of competency were seen as a positive predictor of intrinsic motivation. However, this was not observed to be a positive predictor of academic performance. Next, a Game-Based Learning activity was developed, based on topics of the Valence Shell Electron Pair Repulsion theory. This activity was facilitated both synchronously and asynchronously, exploring the relationships between students’ attitudes, perceived cognitive load, spatial ability, and academic performance. Participants demonstrated significant improvements in spatial ability over the study period. In addition, a moderate correlation was found between spatial ability and VSEPR conceptual understanding. The third educational intervention, constructed within a framework of Cognitive Load Theory, illustrates how AR-supported worked examples may enhance learning of electrophilic aromatic substitution. The achievement motivation of learners was also explored, and how this may be impacted by the provision of AR technology and worked examples. Measures of challenge and interest were found to correlate positively with reported germane load, whereas reported extraneous load negatively correlated with measures of challenge and interest for students displaying higher prior relevant chemistry experience. Lastly, a peer instruction session, focusing on topics of coordination chemistry was facilitated. Students’ self-efficacy, response switching, and discussions were analysed, in addition to their interactions with the ChemFord application. Students with a lower assessment of their problem solving and science communication abilities were significantly more likely to switch their responses from right-to-wrong than students with a high assessment of those abilities
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