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1
Rae, John Patrick. "Explanations and communicative constraints in naturally occurring discourse." Thesis, University of Leeds, 1989. http://etheses.whiterose.ac.uk/345/.
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The subject matter of this thesis are some aspects of the expression of explanations in spoken discourse. The study of explanations has occupied the attention of many researchers in social psychology and in neighbouring disciplines; the study of talk has occupied an even greater number. In the thesis I try to integrate certain areas of these two fields. Chapter one sketches the history of the concern with language which has characterised developments in the social sciences this century. This chapter is incidentally an introduction to some of the key themes of the thesis and to why I think research based on naturally occurring discourse is important. Research on explanations in social psychology has been dominated by research which has gone on under the heading of attribution theory. In chapter two I address a controversy in the application of concepts drawn from attribution theory to clinical psychology, namely whether or not people have fixed styles in the way that they attribute causes for outcomes. Studying family therapy sessions and interviews with parents with a coding procedure I show that the variety of possible styles is broader than has been suggested previously. Chapter three further pursues causal expressions as cases of explanations by asking what a causal statement is. The chapter opens with a discussion of how causes relate to reasons concluding that reasons are a species of cause. I then go on to use data from earlier work to study what expressions speakers use to make causal utterances. The direction of enquiry has been to suggest that rather than studying causal beliefs it is causal utterances that are under study. An utterance is, if you like, "situated", that is to say, what a speaker says is context-bound. I talk of "communicative constraints" operating here. Chapter four reviews some work in the study of conversation with an eye to elucidating the sense in which a speaker's utterances are a product of the situation in which they occur and to look at the researchability of this intuition. Practical and conceptual reasons suggest that the approach generally known as conversation analysis stemming from the study of ethnomethodology is the most interesting and fruitful way toproceed (in this context). Chapters five and six report studies of a computing advisory centre showing 1, the range of accounting procedures which occur as part of the business-at-hand in these sessions, 2, how speakers' utterances, can change within a single conversation. Chapter six looks at the integration of non-vocal behaviour and by considering data on this argues that the idea of normativity, rather than a quasi grammatical notion, is the appropriate level of explanation for the regularities which we find in human interaction. In moving away from beliefs as the object of analysis I could be accused of taking an anti-cognitive stance. Chapter seven explores cognitive versus interactional perspectives in communication. Chapter eight reflects on the approach which I have adopted and suggests how inspite, indeed through, its focus on situational events an account of the capacities drawn on in offering explanations can itself illuminate phenomena seen as beyond its grasp
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Alsahil, Asma, and Asma Alsahil. "Social Networking Mediated Intercultural Communicative Competence: Affordances and Constraints." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/621308.
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In the last few decades, Internet mediated intercultural competence has received a great attention in the field of applied linguistics and foreign language (FL) education especially with the evolution of web 2.0 technologies and social networking sites that facilitate interaction and communication between different cultural communities and individuals. Research in the field of Online Intercultural Exchange (OIE) is extremely varied and researchers have focused their attention on various aspects of OIE such as promoting intercultural communicative competence (Belz, 2002; O'Dowd, 2003; Schenker, 2011; Muller Hartman, 2000), facilitating online relationship building (Ware, 2005; Thorne, 2003, Jin & Erben, 2007) and improving writing skills (Ware, 2005; O'Dowd, 2003), developing pragmatic competence (Kinginger & Belz, 2005). Despite the plethora of research in this area, gaps in the literature still exist. First, literature lacks studies on language learners of less commonly taught languages (e.g. Arabic), (Thorne, 2006) and more importantly most of the studies are based on western contexts mainly in Europe and the USA. Second, few studies have explored the potentials of social networking sites on OIE projects in promoting intercultural learning (Aoki, 2009; Jin, 2015). In an effort to fill the gaps in the research, this study links English language learners (Saudis) with Arabic language learners (Americans) to investigate to what extent OIE on Facebook between these two groups of learners contributes to their intercultural communicative competence (ICC), specifically, exploring how and what are the components of Byram's model (ICC) manifested in the OIE project. Furthermore, it examined the affordances of Facebook in the OIE project according to students' use, practice and perception. Informed by a sociocultural framework, this study took a constructivist mixed methods approach to analysis of data from learners' online discourse on Facebook, the researcher's journal and observations, pre-survey, semi-structured interviews, and a questionnaire. Data analysis and interpretation revealed that when students' participation were mutually compatible, the students were able to build meaningful relationships, used a range of various questioning techniques, and engaged in genuine dialogue, OIE has a great potential for developing students' intercultural competence, as many objectives of Byram's ICC model were manifested. Findings also revealed that the project has strengthened Saudi students' cultural identity as they found the space to present their culture and country beyond the stereotypical image that dominates the media. As with regard to Facebook affordances, findings showed that the semiotic design and various semiotic resources of Facebook (e.g. multimodal posts, sharing, notification, friending, semi-automated features, etc.) afford students' engagement in intercultural discussion, students' collaboration, and students' interpersonal relationship building. The study also identified some of Facebook's constraints that limited students' participation due to technological, cultural and social factors. In sum this study illuminates the nature of online intercultural communication between Arabic and English language learners, contributing to the scarce research on this population. It also uncovers the unique affordances as well as constraints of Facebook on an OIE project. Based on this study, several pedagogical implications and suggestions are made for future research in the field of online intercultural exchanges.
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Hilton, Linda, and n/a. "Interaction in the second language classroom : power and the presence of communicative constraints." University of Canberra. Education, 1999. http://erl.canberra.edu.au./public/adt-AUC20060724.140733.
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This theoretical thesis investigates the effects of communicative constraints within
a second language (L2) classroom with the purpose of developing ways of
exploiting and modifying these constraints to improve L2 learning.
This investigation incorporates the identification of hierarchical structures,
teaching and learning practices which constrain L2 learning within the classroom.
The hierarchical structures of institutional power relations and the authority of the
teacher guide set goals and assessment. However, L2 learners may have different
expectations to those of their teachers. Therefore, in the presentation of an
understanding of classroom genre, this thesis analyses the inherent logic or
common fallacies of thinking and practice within L2 classrooms and further, the
individual experience which each L2 learner brings to the classroom situation.
This thesis examines classroom constraints which prevent L2 learners from
developing an appropriate range of experiences to enable them to participate in
authentic social interaction. Cultural, linguistic and educational disciplinary
views are engaged in the description of these substantive problems.
L2 learners invariably experience difficulties in communication when they interact
socially within their L2 culture, outside the classroom. Learners often lack the
experience to express self-purpose within cultural genres because previous
classroom learning may have been based upon situation-specific and context-determined
patterns of communication and practice.
Such patterns and practices are an inherent part of the classroom because the
classroom is a specific genre itself and consequently classroom talk is very
different from talk in other places.
This thesis develops alternative hypotheses which incorporate critical findings
pertaining to L2 classroom practices. Further, a project for realistic solutions to
L2 learning is offered. These solutions have been developed from the recognition
that learning a L2 in a classroom-based situation is a process which lacks the
diversity of everyday societal life.
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Abu-Talag, Salem Etaher Mustafa. "Libyan secondary school EFL teachers and communicative language teaching : attitudes, beliefs and constraints in implementation." Thesis, Durham University, 2016. http://etheses.dur.ac.uk/11429/.
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The communicative approach to language teaching is based on the theory of language as communication. According to Hymes (1972), language teaching is interpreted by learners as learning through communicative competence. Researchers, particularly in EFL secondary teachers’ classroom practices, have emphasized teachers’ concentration on using grammar translation (GTM) and audio-lingual (ALM) methods. However, most studies did not investigate teachers’ beliefs (as situated in their cultural context) and their classroom practice. Therefore, taking Libya as an example, the aim of this study is to find out whether EFL secondary teachers implement the CLT approach in their classrooms. A data collection triangulation method was utilized involving different research tools. Firstly, an evaluation of a questionnaire distributed to 24 participating Libyan teachers was carried out. Secondly, classroom observations of the same teachers were conducted, applying the communicative orientation of language teaching observation scheme (COLT). Here, the four categories derived from the literature on CLT are employed to determine whether the teaching methodology is communicative. Finally, the same teachers were interviewed to investigate their beliefs and attitudes concerning the CLT approach and its practicality. The results of the qualitative and quantitative data analyses indicated that teachers do not implement the CLT approach. This is due to several factors: low teacher language proficiency; over-reliance on textbooks; class size; time limitations; and lack of adequate training in classroom implementation. An analysis of challenges teachers encounter in implementing CLT and recommendations arising from the study constitute the final chapter of this research.
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Tatikonda, Sekhar Chandra. "Control under communication constraints." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/16755.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.Includes bibliographical references (p. 224-228).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
by Sekhar Chandra Tatikonda.
Ph.D.
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Uney, Murat. "Decentralized Estimation Under Communication Constraints." Phd thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12611226/index.pdf.
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In this thesis, we consider the problem of decentralized estimation under communication
constraints in the context of Collaborative Signal and Information Processing. Motivated
by sensor network applications, a high volume of data collected at distinct locations and
possibly in diverse modalities together with the spatially distributed nature and the
resource limitations of the underlying system are of concern. Designing processing
schemes which match the constraints imposed by the system while providing a
reasonable accuracy has been a major challenge in which we are particularly interested
in the tradeoff between the estimation performance and the utilization of communications
subject to energy and bandwidth constraints.
One remarkable approach for decentralized inference in sensor networks is to exploit
graphical models together with message passing algorithms. In this framework, after the
so-called information graph of the problem is constructed, it is mapped onto the
underlying network structure which is responsible for delivering the messages in
accordance with the schedule of the inference algorithm. However it is challenging to
provide a design perspective that addresses the tradeoff between the estimation
accuracy and the cost of communications. Another approach has been performing the
estimation at a fusion center based on the quantized information provided by the
peripherals in which the fusion and quantization rules are sought while taking a restricted
set of the communication constraints into account.
We consider two classes of in-network processing strategies which cover a broad range
of constraints and yield tractable Bayesian risks that capture the cost of communications
as well as the penalty for estimation errors. A rigorous design setting is obtained in the
form of a constrained optimization problem utilizing the Bayesian risks. These
processing schemes have been previously studied together with the structures that the
solutions exhibit in the context of decentralized detection in which a decision out of
finitely many choices is made.
We adopt this framework for the estimation problem. However, for the case,
computationally infeasible solutions arise that involve integral operators that are
impossible to evaluate exactly in general. In order not to compromise the fidelity of the
model we develop an approximation framework using Monte Carlo methods and obtain
particle representations and approximate computational schemes for both the in-network
processing strategies and the solution schemes to the design problem. Doing that, we
can produce approximating strategies for decentralized estimation networks under
communication constraints captured by the framework including the cost. The proposed
Monte Carlo optimization procedures operate in a scalable and efficient manner and can
produce results for any family of distributions of concern provided that samples can be
produced from the marginals. In addition, this approach enables a quantification of the
tradeoff between the estimation accuracy and the cost of communications through
a parameterized Bayesian risk.
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Craparo, Emily M. (Emily Marie) 1980. "Cooperative exploration under communication constraints." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/46558.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2008.Includes bibliographical references (leaves 131-137).
The cooperative exploration problem necessarily involves communication among agents, while the spatial separation inherent in this task places fundamental limits on the amount of data that can be transmitted. However, the impact of limited communication on the exploration process has not been fully characterized. Existing exploration algorithms do not realistically model the tradeoff between expansion, which allows more rapid exploration of the area of interest, and maintenance of close relative proximity among agents, which facilitates communication. This thesis develops new algorithms applicable to the problem of cooperative exploration under communication constraints. The exploration problem is decomposed into two parts. In the first part, cooperative exploration is considered in the context of a hierarchical communication framework known as a mobile backbone network. In such a network, mobile backbone nodes, which have good mobility and communication capabilities, provide communication support for regular nodes, which are constrained in movement and communication capabilities but which can sense the environment. New exact and approximation algorithms are developed for throughput optimization in networks composed of stationary regular nodes, and new extensions are formulated to take advantage of regular node mobility. These algorithms are then applied to a cooperative coverage problem. In the second part of this work, techniques are developed for utilizing a given level of throughput in the context of cooperative estimation. The mathematical properties of the information form of the Kalman filter are leveraged in the development of two algorithms for selecting highly informative portions of the information matrix for transmission. One algorithm, a fully polynomial time approximation scheme, provides provably good results in computationally tractable time for problem instances of a particular structure. The other, a heuristic method applicable to instances of arbitrary matrix structure, performs very well in simulation for randomly-generated problems of realistic dimension.
by Emily M. Craparo.
Ph.D.
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Kittichokechai, Kittipong. "Communication With Reconstruction and Privacy Constraints." Doctoral thesis, KTH, Kommunikationsteori, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-145134.
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Communication networks are an integral part of the Internet of Things (IoT) era. They enable endless opportunities for connectivity in a wide range of applications, leading to advances in efficiency of day-to-day life. While creating opportunities, they also incur several new challenges. In general, we wish to design a system that performs optimally well in all aspects. However, there usually exist competing objectives which lead to tradeoffs. In this thesis, driven by several applications, new features and objectives are included into the system model, making it closer to reality and needs. The results presented in this thesis aim at providing insight into the fundamental tradeoff of the system performance which can serve as a guideline for the optimal design of real-world communication systems. The thesis is divided into two parts. The first part considers the aspect of signal reconstruction requirement as a new objective in the source and channel coding problems. In this part, we consider the framework where the quality and/or availability of the side information can be influenced by a cost-constrained action sequence. In the source coding problem, we impose a constraint on the reconstruction sequence at the receiver that it should be reproduced at the sender, and characterize the fundamental tradeoff in the form of the rate-distortion-cost region, revealing the optimal relation between compression rate, distortion, and action cost. The channel coding counterpart is then studied where a reconstruction constraint is imposed on the channel input sequence such that it should be reconstructed at the receiver. An extension to the multi-stage channel coding problem is also considered where inner and outer bounds to the capacity region are given. The result on the channel capacity reveals interesting consequence of imposing an additional reconstruction requirement on the system model which has a causal processing structure. In the second part, we consider the aspect of information security and privacy in lossy source coding problems. The sender wishes to compress the source sequence in order to satisfy a distortion criterion at the receiver, while revealing only limited knowledge about the source to an unintended user. We consider three different aspects of information privacy. First, we consider privacy of the source sequence against the eavesdropper in the problem of source coding with action-dependent side information. Next, we study privacy of the source sequence due to the presence of a public helper in distributed lossy source coding problems. The public helper is assumed to be either a user who provides side information over a public link which can be eavesdropped, or a legitimate user in the network who helps to relay information to the receiver, but may not ignore the information that is not intended for it. Lastly, we take on a new perspective of information privacy in the source coding problem. That is, instead of protecting the source sequence, we are interested in the privacy of the reconstruction sequence with respect to a user in the system. For above settings, we provide the complete characterization of the rate-distortion(-cost)-leakage/equivocation region or corresponding inner and outer bounds for discrete memoryless systems.QC 20140514
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El, Gamal Mostafa. "Distributed Statistical Learning under Communication Constraints." Digital WPI, 2017. https://digitalcommons.wpi.edu/etd-dissertations/314.
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"In this thesis, we study distributed statistical learning, in which multiple terminals, connected by links with limited capacity, cooperate to perform a learning task. As the links connecting the terminals have limited capacity, the messages exchanged between the terminals have to be compressed. The goal of this thesis is to investigate how to compress the data observations at multiple terminals and how to use the compressed data for inference. We first focus on the distributed parameter estimation problem, in which terminals send messages related to their local observations using limited rates to a fusion center that will obtain an estimate of a parameter related to the observations of all terminals. It is well known that if the transmission rates are in the Slepian-Wolf region, the fusion center can fully recover all observations and hence can construct an estimator having the same performance as that of the centralized case. One natural question is whether Slepian-Wolf rates are necessary to achieve the same estimation performance as that of the centralized case. In this thesis, we show that the answer to this question is negative. We then examine the optimality of data dimensionality reduction via sufficient statistics compression in distributed parameter estimation problems. The data dimensionality reduction step is often needed especially if the data has a very high dimension and the communication rate is not as high as the one characterized above. We show that reducing the dimensionality by extracting sufficient statistics of the parameter to be estimated does not degrade the overall estimation performance in the presence of communication constraints. We further analyze the optimal estimation performance in the presence of communication constraints and we verify the derived bound using simulations. Finally, we study distributed optimization problems, for which we examine the randomized distributed coordinate descent algorithm with quantized updates. In the literature, the iteration complexity of the randomized distributed coordinate descent algorithm has been characterized under the assumption that machines can exchange updates with an infinite precision. We consider a practical scenario in which the messages exchange occurs over channels with finite capacity, and hence the updates have to be quantized. We derive sufficient conditions on the quantization error such that the algorithm with quantized update still converge."
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Joseph, Jose. "UAV Path Planning with Communication Constraints." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1563872872304696.
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Raja, Sharan. "Learning communication policies for decentralized task allocation under communication constraints." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/128998.
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Thesis: S.M., Massachusetts Institute of Technology, Computation for Design and Optimization Program, 2020Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 57-60).
Multi-UAS teams often operate in ad-hoc communication networks where blind application of consensus algorithms perform poorly because of message intensive nature of such algorithms. Important messages can get lost due to interference or collisions with other messages, and the broadcasting of less important messages can limit the effective bandwidth available for the team. This thesis presents a novel algorithm - Communication-aware CBBA (CA-CBBA) that learns a cooperative communication policy for agents performing decentralized task allocation using consensus based bundle algorithm (CBBA) by accounting for these communication issues. In our approach, agents learn to use features, such as local communication graph density and value of their own messages, to both censor and schedule themselves amongst the other agents competing for shared communication medium. Experiments show that the learned communication policy enables more efficient utilization of the shared medium by prioritizing agents with important messages and more frequently censoring agents in denser parts of the network to alleviate the "hidden node problem." The approach is shown to lead to better task allocation outcomes with faster convergence time and conflict resolution rates compared to CBBA in communication-constrained environments. Policy learnt by agents trained on a specific team size and task number is shown to generalize to larger team sizes in task allocation problems with varying task numbers. To our knowledge, this is the first task allocation algorithm to co-design planning algorithm and communication protocol by incorporating communication constraints into the design process; resulting in better task allocation outcomes in communication-constrained environments.
by Sharan Raja.
S.M.
S.M. Massachusetts Institute of Technology, Computation for Design and Optimization Program
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Tolston, Michael T. "Movement constraints on interpersonal coordination and communication." University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1353155491.
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Reed, Brooks Louis-Kiguchi. "Controller design for underwater vehicle systems with communication constraints." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/97773.
Full textAbstract:
Thesis (Ph. D.)--Joint Program in Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Mechanical Engineering; and the Woods Hole Oceanographic Institution), 2015.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 181-201).
Real-time cooperation between autonomous vehicles can enable time-critical missions such as tracking and pursuit of a dynamic target or environmental feature, but relies on wireless communications. Underwater, communication over distances beyond about one hundred meters is almost exclusively accomplished through acoustics, which bring challenges such as propagation delays, low data rates, packet loss, and scheduling constraints due to interference and limited bandwidth. These limitations make underwater pursuit missions preeminent applications of networked control. Motivated by such applications, this thesis presents contributions towards multi-vehicle feedback control in the presence of severe communication constraints. The first major area of work considers the formulation and solution of new underwater multi-vehicle tracking and pursuit problems using closed-loop control. We begin with a centralized robust optimization approach for multicast routing and power control which is suitable for integration with vehicle control. Next, we describe field experiments in range-based target pursuit at high tracking bandwidths in a challenging shallow-water environment. Finally, we present a methodology for pursuit of dynamic ocean features such as fronts, which we validate using hindcast ocean model data. The primary innovation is a projection algorithm which carries out linearization of ocean model forecast dynamics and uncertainty directly in vehicle coordinates via a forward model technique. The resulting coupled linear stochastic system is suitable for networked control. The second area of work presents a unified formalism for multi-vehicle control and estimation with measurement, control, and acknowledgment packets all subject to scheduling, delays and packet loss. The modular framework we develop is built around a jump linear system description incorporating receding horizon optimization and buffering at actuators. Integration of these elements enables synthesis of a novel technique for estimation using delayed and lossy control acknowledgments-a desirable and practical capability of fielded systems that has not been considered to date. Simulations and field experiments demonstrate the effectiveness of our approach.
by Brooks Louis-Kiguchi Reed.
Ph.D.
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Phago, Setotolwane Johannes. "Internationalisation constraints : a South African information and communication technologies entrepreneur’s perspective." Diss., University of Pretoria, 2010. http://hdl.handle.net/2263/25626.
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There are constraints hindering South Africa‘s ICT entrepreneurs form being internationally competitive. The purpose of this research was to explore them through experiential surveying of South African ICT experts who have successfully internationalised. The outcome of the research was an understanding of both internal organisational constraints and external environmental constraints. Six constraints were explored in detail: human resource, strategy and finance from within the enterprise and political/regulatory, economic and socio-cultural within the environment. It was established that internal constraints exert more influence than external constraints. Human resource was the critical constraint followed by financing which could be influenced both externally and internally. Other constraints are also explored including technology constraints and lack of national planning and collaboration. Recommendations are made to stakeholders. CopyrightDissertation (MBA)--University of Pretoria, 2011.
Gordon Institute of Business Science (GIBS)
unrestricted
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Carvalho, Filho José Gilmar Nunes de. "Multi-robot exploration with constrained communication." reponame:Repositório Institucional da UFSC, 2016. https://repositorio.ufsc.br/xmlui/handle/123456789/171998.
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Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia de Automação e Sistemas, Florianópolis, 2016.Made available in DSpace on 2016-12-27T03:11:05Z (GMT). No. of bitstreams: 1 342277.pdf: 5444057 bytes, checksum: 36965f3be2f7f870b8ed9ef5eee8e702 (MD5) Previous issue date: 2016
Abstract : Over the last two decades, several methods for exploration with Multi-Robot Systems (MRS) have been proposed, most of them based on the allocation of frontiers (exploration targets) and typically applying local optimization policies. However, communication issues have usually been neglected. This thesis investigates multi-robot exploration by considering that robots have limited communication radius. Two methods, one based on a flat network architecture (DSM) and another based on a hierarchical architecture (HSM), were proposed to share map information. While DSM considers a propagation scheme to share information and synchronize the map of robots, HSM organizes robots in a hierarchical architecture where some robots act as leaders (clusterheads) and are responsible for synchronizing the maps of the robots in the network. Formal proof that both methods guarantee the synchronization of the map of all robots in a network is presented. In addition, experiments were conducted by considering systems with different number of robots, network topologies and different map's sizes. The results show that both methods are able to synchronize the map of the robots when they can lose communication links, but HKM usually presents smaller convergence time, number of exchanged messages and amount of transmitted data. We also propose Hierarchical K-Means (HKME), a method for multi-robot coordination in exploration tasks that handles communication problems, such as link losses. To handle communication among robots, HKME arranges them into clusters and elects leaders for each. Clusters evolve dynamically as robots lose or establish communication with their peers. HKME uses HSM to guarantee that the map of the robots are synchronized and also uses the hierarchical organization of the robots to coordinate them in order to minimize the variance of the time at which they reach all regions of the workspace, while balancing their workload and decreasing the exploration time. Experiments were conducted by considering different types of workspace and communication radius. The results show that HKME behaves like a centralized algorithm when communication is granted, while being able to withstand severe degradation in communication radius.
Ao longo das últimas décadas, vários métodos de exploração com os Sistemas Multi-robôs (SMR) têm sido propostos, a maioria deles com base na alocação de fronteiras (alvos de exploração) e normalmente aplicando políticas de otimização locais. No entanto, os problemas de comunicação têm geralmente sido negligenciados. Esta tese investiga a exploração multi-robô, considerando que os robôs têm raio de comunicação limitado. Dois métodos, um baseado em uma arquitetura de rede plana (DSM) e outro baseado em uma arquitetura hierárquica (HSM), foram propostos para compartilhar informações de mapa. Enquanto o DSM considera um esquema de propagação para compartilhar informações e sincronizar o mapa dos robôs, o HSM organiza robôs em uma arquitetura hierárquica, onde alguns robôs atuam como líderes (clusterheads) e são responsáveis por sincronizar os mapas dos robôs na rede. A prova formal de que ambos os métodos garantem a sincronização do mapa de todos os robôs na rede é apresentada. Além disso, experimentos foram conduzidos considerando sistemas com diferentes números de robôs, topologias de rede e tamanhos de mapa. Os resultados mostram que ambos os métodos são capazes de sincronizar o mapa dos robôs quando eles podem perder links de comunicação, mas o HKM geralmente apresenta menor tempo de convergência, o número de mensagens trocadas e a quantidade de dados transmitidos. Propomos também Hierarchical K-Means (HKME), um método de coordenação multi-robô em tarefas de exploração que lida com problemas de comunicação, tais como perdas de links. Para lidar com a comunicação entre robôs, o HKME os organiza em clusters e elege os líderes de cada um. Clusters evoluem dinamicamente a medida que os robôs perdem ou estabelecem links de comunicação. O HKME usa o HSM para garantir que o mapa dos robôs se mantenham sincronizados e também usa a organização hierárquica dos robôs para coordená-los, a fim de minimizar a variância do momento em que eles atinjem todas as regiões do espaço de trabalho, ao mesmo tempo que equilibra a carga de trabalho e diminui o tempo de exploração. Experimentos foram realizadas considerando diferentes tipos de espaço de trabalho e raios de comunicação. Os resultados mostram que o HKME comporta-se como um algoritmo centralizada quando a comunicação é garantida, sendo capaz de lidar com uma degradação severa no raio de comunicação.
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Speranzon, Alberto. "On control under communication constraints in autonomous multi-robot systems /." Stockholm : KTH, Signals, Sensors and Systems, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-570.
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Rost, Peter Matthias R. "Opportunities, benefits, and constraints of relaying in mobile communication systems." Dresden Vogt, 2009. http://d-nb.info/996421831/04.
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Spirin, Victor. "Multi-agent exploration of indoor environments under limited communication constraints." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:b337a9a7-91c7-451c-b32f-b1cd05ef983d.
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This thesis considers cooperation strategies for teams of agents autonomously exploring an unknown indoor environment under limited communication constraints. The primary application considered is Urban Search-and-Rescue, although other applications are possible, such as surveying hazardous areas. We focus on developing cooperation strategies that enable periodic communication between the exploring agents and the base station (human operators). Such strategies involve an inherent trade-off between allocating team resources towards facilitating communication and increasing the speed of exploration. We propose two classes of approaches to address this problem: using opportunistic rendezvous to guide the team behaviour, and explicitly arranging rendezvous between agents. In the opportunistic approach, the allocation of team resources between exploration and communication can be indicated with a single numerical parameter between 0 and 1 -- the return ratio -- which leads to complex emergent cooperative behaviour. We show that in some operating environments agents can benefit from explicitly arranging rendezvous. We propose a novel definition of a rendezvous location as a tuple of points and show how such locations can be generated so that the topology of the environment and the communication ranges of agents can be exploited. We show how such rendezvous locations can be used to both improve the speed of exploration and to improve team connectivity by allowing relays to contribute to the overall exploration. We evaluate these approaches extensively in simulation and discuss their applicability in search-and-rescue scenarios.
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Hua, Qiangsheng, and 華強勝. "Scheduling wireless links with SINR constraints." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42664627.
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Hua, Qiangsheng. "Scheduling wireless links with SINR constraints." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B42664627.
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Buehler, Christopher James 1974. "An instruction scheduling algorithm for communication-constrained microprocessors." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/46254.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.Includes bibliographical references (p. 130-132).
This thesis describes a new randomized instruction scheduling algorithm designed for communication-constrained VLIW-style machines. The algorithm was implemented in a retargetable compiler system for testing on a variety a different machine configurations. The algorithm performed acceptably well for machines with full communication, but did not perform up to expectations in the communication-constrained case. Parameter studies were conducted to ascertain the reason for inconsistent results.
by Christopher James Buehler.
S.M.
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Roy, Prateep Kumar. "Analysis & design of control for distributed embedded systems under communication constraints." Phd thesis, Université Paris-Est, 2009. http://tel.archives-ouvertes.fr/tel-00534012.
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Les Systèmes de Contrôle Embarqués Distribués (SCED) utilisent les réseaux de communication dans les boucles de rétroaction. Étant donné que les systèmes SCED ont une puissance de batterie, une bande passante de communication et une puissance de calcul limitée, les débits des données ou des informations transmises sont bornées et ils peuvent affecter leur stabilité. Ceci nous amène à élargir le spectre de notre étude et y intégrer une étude sur la relation entre la théorie du contrôle d'un coté et celle de l'information de l'autre. La contrainte de débit de données induit la quantification des signaux tandis que les aspects de calcul temps réel et de communication induit des événements asynchrones qui ne sont plus réguliers ou périodiques. Ces deux phénomènes donnent au SCED une double nature, continue et discrète, et en font des cas d'étude spécifiques. Dans cette thèse, nous analysons la stabilité et la performance de SCED du point de vue de la théorie de l'information et du contrôle. Pour les systèmes linéaires, nous montrons l'importance du compromis entre la quantité d'information communiquée et les objectifs de contrôle, telles que la stabilité, la contrôlabilité/observabilité et les performances. Une approche de conception conjointe de contrôle et de communication (en termes de débit d'information au sens de Shannon) des SCED est étudiée. Les principaux résultats de ces travaux sont les suivants : nous avons prouvé que la réduction d'entropie (ce qui correspond à la réduction d'incertitude) dépend du Grammien de contrôlabilité. Cette réduction est également liée à l'information mutuelle de Shannon. Nous avons démontré que le Grammien de contrôlabilité constitue une métrique de l'entropie théorique de l'information en ce qui concerne les bruits induits par la quantification. La réduction de l'influence de ces bruits est équivalente à la réduction de la norme du Grammien de contrôlabilité. Nous avons établi une nouvelle relation entre la matrice d'information de Fisher (FIM) et le Grammien de Contrôlabilité (CG) basé sur la théorie de l'estimation et la théorie de l'information. Nous proposons un algorithme qui distribue de manière optimale les capacités de communication du réseau entre un nombre "n" d'actionneurs et/ou systèmes concurrents se basant sur la réduction de la norme du Grammien de Contrôlabilité
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Sosteric, Mike. "Electronic journals and the transformation of scholarly communication, constraints and technical possibilities." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0018/NQ46922.pdf.
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Maalouf, Hoda William. "Optimisation of the communication network performance of distributed systems with resequencing constraints." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287502.
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Gupta, Vijay. "Design of information flow for networked control systems : control under communication constraints /." Saarbrücken : VDM Verlag Dr. Müller, 2007. http://d-nb.info/985597402/04.
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Ajwad, Syed Ali. "Distributed control of multi-agent systems under communication constraints : application to robotics." Thesis, Poitiers, 2020. http://www.theses.fr/2020POIT2264.
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Les Systèmes Multi-Agents (SMA) ont gagné en popularité en raison de leur vaste gamme d'applications. Les SMA sont utilisés pour atteindre des objectifs complexes qui ne pourraient être atteints par un seul agent. La communication et l'échange d'informations entre les agents d'un SMA sont essentiels pour contrôler son comportement coopératif. Les agents partagent leurs informations avec leurs voisins pour atteindre un objectif commun, ils n'ont donc pas besoin d'unité centrale de surveillance. Cependant, la communication entre les agents est soumise à diverses contraintes pratiques. Ces contraintes incluent des périodes d'échantillonnage irrégulières et asynchrones et la disponibilité d'états partiels uniquement. Ces contraintes posent des défis théoriques et pratiques importants. Dans cette thèse, nous étudions deux problèmes fondamentaux liés au contrôle coopératif distribué, à savoir le consensus et le contrôle de formation pour un SMA à double intégrateur sous ces contraintes. On considère que chaque agent du réseau ne peut mesurer et transmettre son état de position qu'à des instants d'échantillonnage non uniformes et asynchrones. De plus, la vitesse et l'accélération ne sont pas disponibles. Dans un premier temps, nous étudions le problème du contrôle distribué du suivi de consensus. Un algorithme de suivi de leader basé sur l'observateur à temps discret continu est proposé. L'observateur estime la position et la vitesse de l'agent et de son voisin en temps continu à partir des données de position échantillonnées disponibles. Ces états estimés sont ensuite utilisés pour le calcul de l'entrée de commande. Les scénarios de topologie fixe et de topologie commutée sont discutés. Deuxièmement, un protocole de suivi de formation distribué basé sur le consensus est conçu pour réaliser des modèles de formation fixes et variant dans le temps. Le problème d'évitement de collision est également étudié dans cette thèse. Un mécanisme d'évitement de collision basé sur la fonction de potentiel artificiel (APF) est incorporé à l'algorithme de suivi de formation pour empêcher les collisions entre les agents tout en convergeant vers la position souhaitée. Enfin, les algorithmes proposés sont appliqués sur un réseau multi-robots, composé de robots à entraînement différentiel utilisant Robot Operating System (ROS). Un nouveau schéma est proposé pour faire face aux contraintes non holonomiques du robot. L'efficacité des algorithmes sont démontrées à la fois par des résultats de simulation et des expérimentationsMulti-agent systems (MAS) have gained much popularity due to their vast range of applications. MAS is deployed to achieve more complex goals which could not be realized by a single agent alone. Communication and information exchange among the agents in a MAS is crucial to control its cooperative behavior. Agents share their information with their neighbors to reach a common objective, thus do not require any central monitoring unit. However, the communication among the agents is subject to various practical constraints. These constraints include irregular and asynchronous sampling periods and the availability of partial states only. Such constraints pose significant theoretical and practical challenges. In this thesis, we investigate two fundamental problems related to distributed cooperative control, namely consensus and formation control, of double-integrator MAS under these constraints. It is considered that each agent in the network can measure and transmit its position state only at nonuniform and asynchronous sampling instants. Moreover, the velocity and acceleration are not available. First, we study the problem of distributed control of leader-following consensus. A continuous-discrete time observer based leader-following algorithm is proposed. The observer estimates the position and velocity of the agent and its neighbor in continuous time from the available sampled position data. Then these estimated states are used for the computation of the control input. Both fixed and switching topology scenarios are discussed. Secondly, a consensus based distributed formation tracking protocol is designed to achieve both fixed and time-varying formation patterns. Collision avoidance problem is also studied in this thesis. An Artificial Potential Function (APF) based collision avoidance mechanism is incorporated with the formation tracking algorithm to prevent collisions between the agents while converging to a desired position. Finally, the proposed algorithms are applied on a multi-robot network, consisting of differential drive robots using Robot Operating System (ROS). A new scheme is proposed to deal with nonholonomic constraints of the robot. Efficiency of the designed algorithms and their effectiveness in real world applications are shown through both simulation and hardware results
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Fristedt, Saga. "Communication, collaboration and belongingness in virtual teams : mapping out enablers and constraints." Thesis, Malmö universitet, Malmö högskola, Institutionen för datavetenskap och medieteknik (DVMT), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-40716.
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In an increasingly digital world, virtual work becomes more common every year. Additionally, virtual work has suddenly become the reality for a large part of the world’s population due to the coronavirus pandemic. Therefore, a study on virtual teamwork is currently of high relevance. The purpose of this study is to gain a deeper understanding and provide knowledge on enablers and constraints for communication, collaboration and belongingness in virtual teams as well as ICTs impact on the virtual teamwork. The study has a phenomenological research design with a qualitative approach. Empirical data has been collected by studying three transnational, virtual teams by conducting six semi-structured individual interviews. The sample was selected through a strategic selection. A thematic analysis has been conducted to compile and analyze the data, which thereafter has been set in relation to the theoretical framework of the study. The enablers found in the results were flexibility and availability for communication, clearly defined roles, high level of both task- and relationship based communication as well as depth of relationships, trust and shared understanding for collaboration, and responsibility, seeing into team members homes and virtual social team activities for belongingness. Additionally, ICTs were found as a main enabler for all themes. The identified constraints were time dispersion for all three themes, as well as virtuality as a whole. Additionally misunderstandings was identified for collaboration and lack of natural and spontaneous social conversation for belongingness. Furthermore, the findings implicate that ICTs with characteristics of richer type in relation to media richness are preferred most of the time to enable a better virtual work climate regards to communication, collaboration and belongingness. However, some criteria for media richness cannot be fully utilized in virtual teams due to time dispersion. Lastly, findings implicate that the choice of ICT based on previous experience, rather than linked to suitability, might hinder an optimal model of ICT usage for a well-functioning virtual team.I en allt mer digitaliserad värld blir virtuellt arbete vanligare varje år. Virtuellt arbete har dessutom hastigt blivit verklighet för en stor del av världens befolkning på grund av coronapandemin. Därför är en studie om virtuellt teamarbete av hög relevans i dagens samhälle. Syftet med denna studie är att få en djupare förståelse och ge kunskap om möjliggörare och begränsningar för kommunikation, samarbete och tillhörighet i virtuella team samt ICTs inverkan på virtuellt teamarbete. Studien har en fenomenologisk forskningsdesign med ett kvalitativt tillvägagångssätt. Empirisk data har samlats in genom att studera tre transnationella, virtuella team genom genomförandet av sex semi-strukturerade, individuella intervjuer. Intervjupersonerna valdes ut genom ett strategiskt urval. En tematisk analys har genomförts för att sammanställa och analysera data, som sedan satts i förhållande till det teoretiska ramverket för studien. De möjliggörande faktorer som hittades i resultaten var flexibilitet och tillgänglighet för kommunikation, tydligt definierade roller, hög nivå av både uppgifts- och relationsbaserad kommunikation och relationsdjup, förtroende och delad förståelse för samarbete, samt ansvar, att få en inblick i teammedlemmarnas hem och virtuella sociala teamaktiviteter för tillhörighet. Dessutom identifierades ICT som en övergripande möjliggörare. De identifierade begränsningarna var tidsskillnader för alla tre teman samt virtualitet i helhet. Utöver detta var missförstånd identifierat för samarbete och brist på naturlig och spontan social interaktion för tillhörighet. Dessutom visar resultaten på att ICTs med egenskaper av rikare typ i förhållande till media richness oftast föredras för att möjliggöra ett bättre virtuellt arbetsklimat när det gäller kommunikation, samarbete och tillhörighet. Vissa kriterier för media richness kan dock inte utnyttjas fullt ut i virtuella team på grund av tidsskillnader. Slutligen visar studiens resultat på att val av ICT baserat på tidigare erfarenhet, snarare än kopplat till lämplighet, kan hindra en optimal modell för användning av ICT för ett väl fungerande virtuellt team.
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Nilan, Michael Sanford. "Structural constraints and situational information seeking : a test of two predictors in a sense-making context /." Thesis, Connect to this title online; UW restricted, 1985. http://hdl.handle.net/1773/6185.
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Yang, Fei. "Reliable and time-constrained communication in wireless sensor networks." Phd thesis, INSA de Lyon, 2011. http://tel.archives-ouvertes.fr/tel-00706211.
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Wireless Sensor Networks (WSNs) are composed of a large number of battery-powered sensor nodes that have the ability to sense the physical environment, compute the obtained information and communicate using the radio interfaces. Because sensor nodes are generally deployed on a large and wild area, they are powered by embedded battery. And it is difficult to change or recharge the battery, thus to reduce the energy consumption when sensors and protocols are designed is very important and can extend the lifetime of WSNs. So sensor nodes transmit packets with a lower transmission power (e.g. OdBm). With this transmission power, a packet can only be transmitted dozens of meters away. Therefore, when a sensor detects an event, a packet is sent in a multi-hop, ad-hoc manner (without fixed infrastructure and each sensor is able to relay the packet) to the sink (specific node which gathers information and reacts to the network situation). In this thesis, we first give an elaborate state of the art of WSNs. Then the impacts of duty-cycle and unreliable links or the performances of routing layer are analyzed. Based on the analytical results, we then propose three new simple yet effective methods to construct virtual coordinates under unreliable links in WSNs. By further taking the duty-cycle and real-time constraints into consideration we propose two cross-layer forwarding protocols which can have a greater delivery ratio and satisfy the deadline requirements. In order to have protocols for the WSNs that have dynamic topology, we then propose a robust forwarding protocol which can adapt its parameters when the topology changes. At last, we conclude this thesis and give some perspectives.
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Wen, Zheng. "On the external stability of linear systems with actuator saturation constraints, and the decentralized control of communicating-agent networks with security constraints." Online access for everyone, 2007. http://www.dissertations.wsu.edu/Thesis/Summer2007/z_wen_072307.pdf.
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Speranzon, Alberto. "Coordination, Consensus and Communication in Multi-robot Control Systems." Doctoral thesis, Stockholm : Automatic control, School of Electrical Engineering, Royal Institute of Technology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3955.
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Helmberg, Christoph, Sebastian Richter, and Dominic Schupke. "A Chance Constraint Model for Multi-Failure Resilience in Communication Networks." Universitätsbibliothek Chemnitz, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-175454.
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For ensuring network survivability in case of single component failures many routing protocols provide a primary and a back up routing path for each origin destination pair. We address the problem of selecting these paths such that in the event of multiple failures, occuring with given probabilities, the total loss in routable demand due to both paths being intersected is small with high probability. We present a chance constraint model and solution approaches based on an explicit integer programming formulation, a robust formulation and a cutting plane approach that yield reasonably good solutions assuming that the failures are caused by at most two elementary events, which may each affect several network components.
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Nikbakht, Homa. "Networks with mixed-delay constraints." Electronic Thesis or Diss., Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAT046.
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Les réseaux de communication sans fil modernes doivent s'adapter à différents types de trafic de données avec des contraintes de latence différentes. Les applications vidéo sensibles à la latence, en particulier, représentent une part croissante du trafic de données. En outre, les réseaux modernes doivent accepter des débits de données élevés, ce qu'ils peuvent faire par exemple avec des terminaux coopératifs ou avec l'assistance de relais tels que les drones. Cependant, la coopération introduit généralement des retards de communication supplémentaires et n'est donc pas applicable au trafic de données sensibles à la latence.Cette thèse porte sur les réseaux d'interférence avec des contraintes de latence mixtes et sur les architectures de systèmes où des émetteurs et/ou des récepteurs voisins peuvent coopérer. Dans de tels systèmes, les messages sensibles à la latence doivent être encodés et décodés sans délai et ainsi ne peuvent pas bénéficier des liens de coopération disponibles. Nous proposons différents schémas de codage pour permettre la transmission simultanée de messages sensibles et insensibles à la latence. Pour les schémas proposés, nous analysons les gains de multiplexage (MG) qu'ils réalisent sur le réseau de transfert intercellulaire souple de Wyner, le réseau symétrique de Wyner, le réseau hexagonal et le réseau hexagonal sectorisé. Pour le réseau de transfert souple de Wyner et le réseau symétrique de Wyner, nous identifions aussi des résultats étroits s'agissant de leurs limites en théorie de l'information et nous définissons ainsi l'ensemble exact de paires MG qui peuvent être obtenus simultanément pour les données sensibles et insensibles à la latence. Ces résultats montrent que lorsque les émetteurs et les récepteurs peuvent coopérer et que les taux de coopération sont suffisamment élevés, il est possible d'obtenir le plus grand MG possible pour les messages sensibles à la latence sans pénaliser la somme maximale des MG pour l'ensemble des messages sensibles et insensibles à la latence. Cependant, la somme des MG des systèmes que nous proposons pour le modèle hexagonal est diminuée en présence de données sensibles à la latence. Cette pénalité disparaît dans le cas du réseau hexagonal sectorisé quand chaque cellule est divisée en trois secteurs non interférents en équipant les stations de base d'antennes directionnelles.Nous proposons, de surcroît, des schémas de codage similaires en fonction de différents types d'activité aléatoire de la part des usagers du réseau. Nous considérons plus particulièrement deux configurations. Dans la première configuration, l'augmentation du taux de MG correspondant aux données sensibles à la latence diminue toujours la somme des MG. En revanche, dans la seconde configuration, pour certains paramètres, la plus grande somme des MG est obtenue au maximum du taux de MG correspondant aux données sensibles à la latence et donc l'augmentation des MG sensibles à la latence améliore la somme des MG.Nous étudions aussi un réseau d'accès radio "cloud" avec des contraintes de latence mixtes, c'est-à-dire où chaque utilisateur mobile peut simultanément envoyer un flux sensible à la latence et un flux qui la tolère et où seules les données sensibles sont décodées conjointement au sein du cloud. Pour ce réseau, nous dérivons les limites intérieures et extérieures de la région de capacité sous des contraintes de latence mixtes, et nous caractérisons précisément la région MG optimale. Lorsque le rapport signal/bruit (SNR) est élevé, nos résultats démontrent que, pour des capacités frontales modérées, le MG maximal pour les messages sensibles à la latence reste inchangé sur une large gamme de petits et moyens MG de messages sensibles à la latence. Pour un SNR modéré, les résultats montrent que lorsque le débit de messages sensibles à la latence est faible ou modéré, nous obtenons une somme de débit de données constanteModern wireless communication networks have to accommodate different types of data traffic with different latency constraints. In particular, delay-sensitive video-applications represent an increasing portion of data traffic. Modern networks also have to accommodate high total data rates, which they can accomplish for example with cooperating terminals or with helper relays such as drones. However, cooperation typically introduces additional communication delays, and is thus not applicable to delay-sensitive data traffic.This thesis focuses on interference networks with mixed-delay constraints and on system architectures where neighbouring transmitters and/or neighbouring receivers can cooperate. In such systems, delay-sensitive messages have to be encoded and decoded without further delay and thus cannot benefit from available cooperation links.We propose various coding schemes that can simultaneously accommodate the transmission of both delay-sensitive and delay-tolerant messages. For the proposed schemes we analyze the multiplexing gains (MG) they achieve over Wyner's soft hand-off network, Wyner's symmetric network, the hexagonal network and the sectorized hexagonal network. For Wyner's soft hand-off network and Wyner's symmetric network, we also provide tight information-theoretic converse results and thus establish the exact set of MG pairs that can simultaneously be achieved for delay-sensitive and delay-tolerant data. These results demonstrate that when both transmitters and receivers cooperate and the cooperation rates are sufficiently large, it is possible to achieve the largest MG for delay-sensitive messages without penalizing the maximum sum MG of both delay-sensitive and delay-tolerant messages. In contrast, under our proposed schemes, the sending of delay-sensitive data in hexagonal models decreases the maximum sum MG. This penalty vanishes when we consider the sectorized hexagonal network where each cell is divided into three non-interfering sectors by employing directional antennas at the base stations.We further propose similar coding schemes for scenarios with different types of random user activity. We specifically consider two setups. In the first setup, each active transmitter always has delay-tolerant data to send and delay-sensitive data arrival is random. In the second setup, both delay-tolerant and delay-sensitive data arrivals are random. The obtained MG regions show that in the first setup, increasing the delay-sensitive MG always decreases the sum MG. In contrast, in the second setup, for certain parameters, the highest sum MG is achieved at maximum delay-sensitive MG and thus increasing the delay-sensitive MG provides a gain in sum MG.Additionally, we also study a cloud radio access network with mixed delay constraints, i.e., where each mobile user can simultaneously send a delay-sensitive and a delay-tolerant stream and only the delay-tolerant data is jointly decoded at the cloud unit. For this network, we derive inner and outer bounds on the capacity region under mixed delay constraints, and we exactly characterize the optimal MG region. At high signal-to-noise ratio (SNR), our results show that for moderate fronthaul capacities, the maximum MG for delay-sensitive messages remains unchanged over a large regime of small and moderate MGs of delay-sensitive messages. The sum MG is thus improved if some of the messages can directly be decoded at the base stations. At moderate SNR, the results show that when the data rate of delay-sensitive messages is small or moderate, the achievable sum rate is constant
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Björnemo, Erik. "Energy Constrained Wireless Sensor Networks : Communication Principles and Sensing Aspects." Doctoral thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-9519.
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Wireless sensor networks are attractive largely because they need no wired infrastructure. But precisely this feature makes them energy constrained, and the consequences of this hard energy constraint are the overall topic of this thesis. We are in particular concerned with principles for energy efficient wireless communication and the energy-wise trade-off between sensing and radio communication. Radio transmission between sensors incurs both a fixed energy cost from radio circuit processing, and a variable energy cost related to the level of radiated energy. We here find that transmission techniques that are otherwise considered efficient consumes too much processing energy. Currently available sensor node radios typically have a maximum output power that is too limited to benefit from transmission-efficient, but processing-intensive, techniques. Our results provide new design guidelines for the radio output power. With increasing transmission energy -- with increasing distance -- the considered techniques should be applied in the following order: output power control, polarisation receiver diversity, error correcting codes, multi-hop communication, and cooperative multiple-input multiple-output transmissions. To assess the measurement capability of the network as a whole, and to facilitate a study of the sensing-communication trade-off, we devise a new metric: the network measurement capacity. It is based on the number of different measurement sequences that a network can provide, and is hence a measure of the network's readiness to meet a large number of possible events. Optimised multi-hop routing under this metric reveals that the energy consumed for sensing has decisive impact on the best multi-hop routes. We also find support for the use of hierarchical heterogeneous network structures. Model parameter uncertainties have large impact on our results and we use probability theory as logic to include them consistently. Our analysis shows that common assumptions can give misleading results, and our analysis of radio channel measurements confirms the inadequacy of the Rayleigh fading channel model.wisenet
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Hranilovic, Steve. "Modulation and constrained coding techniques for wireless infrared communication channels." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0005/MQ45987.pdf.
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Yu, Kan. "On Reliable and Deadline-Constrained Communication in Wireless Industrial Networks." Doctoral thesis, Mälardalens högskola, Inbyggda system, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-26165.
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Along with the quick development of wireless communication technologies, industrial automation networks are also in unceasing evolution. Industrial wireless sensor and actuator networks (IWSAN) have been increasingly adopted in industrial automation systems. Although there are a number of advantages of replacing cables with wireless links, such as cost reduction, enhanced scalability and flexibility, the stringent requirements on communication reliability and meeting firm deadlines from industrial mission-critical applications must still be fulfilled. Also, transmissions over wireless channels in industrial environments are prone to noise and interferences, resulting in frequent erroneous packet deliveries. Although industrial automation systems are usually designed to be tolerant of certain communication errors, successive transmission failures may still cause downtime of industrial applications, which might lead to significant economic losses or even serious accidents. This thesis addresses the problems mentioned above and aims to provide reliable and deadline-constrained communication via IWSANs for industrial automation systems. On the MAC layer, existing IWSAN standards utilize automatic repeat request (ARQ) to improve reliability at the cost of additional transmission latency. An alternative method is to use Forward Error Correction (FEC) schemes to provide reliable communication by recovering erroneous data and avoiding unnecessary retransmissions. On the MAC layer, Time Division Multiple Access (TDMA) is usually applied in current IWSAN standards for collision-free and deterministic communication. An inappropriate scheduling scheme may introduce high transmission jitter and degrade the quality of control. On the network layer, routing protocols play an important role in both communication reliability and latency. Existing solutions are either hardly able to fulfill all stringent requirements from the mission-critical industrial applications, too complicated to be realized, or lack verification in reality. The contributions of this thesis consist of (i) the possibilities of using FEC schemes in IWSANs is explored under the requirements of existing standards on the MAC layer. A compatible and flexible FEC scheme on the MAC layer for IWSANs that does not violate the standard is proposed and evaluated by simulations. (ii) To guarantee an acceptable control quality, a TDMA scheduling scheme is presented aiming for low communication jitter, and it is compared to classic scheduling schemes. (iii) The advantages of exploiting flooding in IWSANs is discussed; a reliable controlled flooding-based routing protocol is proposed and compared to both traditional routing protocols and other flooding-based protocols. (iv) A complete IWSAN platform is built and the whole protocol stack is implemented. Measurements were conducted in a real industrial environment to verify the correctness of the proposed solution.
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rahman, md mahbubur. "Efficient Mission Planning for Robot Networks in Communication Constrained Environments." FIU Digital Commons, 2017. http://digitalcommons.fiu.edu/etd/3484.
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Many robotic systems are remotely operated nowadays that require uninterrupted connection and safe mission planning. Such systems are commonly found in military drones, search and rescue operations, mining robotics, agriculture, and environmental monitoring. Different robotic systems may employ disparate communication modalities such as radio network, visible light communication, satellite, infrared, Wi-Fi. However, in an autonomous mission where the robots are expected to be interconnected, communication constrained environment frequently arises due to the out of range problem or unavailability of the signal. Furthermore, several automated projects (building construction, assembly line) do not guarantee uninterrupted communication, and a safe project plan is required that optimizes collision risks, cost, and duration. In this thesis, we propose four pronged approaches to alleviate some of these issues: 1) Communication aware world mapping; 2) Communication preserving using the Line-of-Sight (LoS); 3) Communication aware safe planning; and 4) Multi-Objective motion planning for navigation.
First, we focus on developing a communication aware world map that integrates traditional world models with the planning of multi-robot placement. Our proposed communication map selects the optimal placement of a chain of intermediate relay vehicles in order to maximize communication quality to a remote unit. We also vi propose an algorithm to build a min-Arborescence tree when there are multiple remote units to be served. Second, in communication denied environments, we use Line-of-Sight (LoS) to establish communication between mobile robots, control their movements and relay information to other autonomous units. We formulate and study the complexity of a multi-robot relay network positioning problem and propose approximation algorithms that restore visibility based connectivity through the relocation of one or more robots. Third, we develop a framework to quantify the safety score of a fully automated robotic mission where the coexistence of human and robot may pose a collision risk. A number of alternate mission plans are analyzed using motion planning algorithms to select the safest one. Finally, an efficient multi-objective optimization based path planning for the robots is developed to deal with several Pareto optimal cost attributes.
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Clennett-Sirois, Laurence. "Women blogging in Québec, Canada : surfing between ideals and constraints." Thesis, University of Sussex, 2013. http://sro.sussex.ac.uk/id/eprint/46815/.
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This thesis explores online practices of women in Québec, a culturally and historically distinct province in Canada that is undergoing rapid social and technological transformations, and analyses the discourses that emerge. It zeroes in on blogging, as a facilitator for exploring, constructing and challenging gendered identities. It draws on and contributes to a growing body of literature that investigates and legitimises women's online writings, an area that remains under analysed. This online ethnography was accomplished through face-to-face interviews with 23 Frenchspeaking women bloggers, home visits and an analysis of their blogs. Using feminist critical discourse analysis, the thesis analyses how informants locate themselves inside and outside traditional and mainstream discourses of femininities. It first explores how participants discuss their blogs using domestic metaphors, thereby linking their online expressions to ideas and ideals of the home. Second, it reveals how bloggers share a common concern with putting forward a favourable self, emphasising personal qualities such as education, respect, affability, and impressive online networks. Third, it analyses self-improvement narratives in participants' interviews and blog entries, examining recurring discussions of personality, values and views; body size and image; emotional and mental health; and professional and homemaking skills. The last chapter underlines how blogging provides women with opportunities for networking, a place to discuss challenges and with a means to claim time for themselves. The thesis draws out the complex engagements in an activity they find pleasurable despite working within mainstream gender role constraints and still facing a digital divide. In both discourse and practice, participants seem at ease with blogging but remain highly influenced by traditional discourses. This gives rise to a sense of contradiction where they feel like they exist, have a public life and make a contribution but also exhibit a sense of compulsion and regulation. They break out of the limits of normative femininities perhaps – at the same time creating new 'women's worlds' – even as the use of blogging reinstates and produces conservative forms of self-management.
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Kuri, Joy. "Optimal Control Problems In Communication Networks With Information Delays And Quality Of Service Constraints." Thesis, Indian Institute of Science, 1995. http://hdl.handle.net/2005/162.
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In this thesis, we consider optimal control problems arising in high-speed integrated communication networks with Quality of Service (QOS) constraints. Integrated networks are expected to carry a large variety of traffic sources with widely varying traffic characteristics and performance requirements. Broadly, the traffic sources fall into two categories: (a) real-time sources with specified performance criteria, like small end to end delay and loss probability (sources of this type are referred to as Type 1 sources below), and (b) sources that do not have stringent performance criteria and do not demand performance guarantees from the network - the so-called Best Effort Type sources (these are referred to as Type 2 sources below). From the network's point of view, Type 2 sources are much more "controllable" than Type 1 sources, in the sense that the Type 2 sources can be dynamically slowed down, stopped or speeded up depending on traffic congestion in the network, while for Type 1 sources, the only control action available in case of congestion is packet dropping. Carrying sources of both types in the same network concurrently while meeting the performance objectives of Type 1 sources is a challenge and raises the question of equitable sharing of resources. The objective is to carry as much Type 2 traffic as possible without sacrificing the performance requirements of Type 1 traffic.
We consider simple models that capture this situation. Consider a network node through which two connections pass, one each of Types 1 and 2. One would like to maximize the throughput of the Type 2 connection while ensuring that the Type 1 connection's performance objectives are met. This can be set up as a constrained optimization problem that, however, is very hard to solve. We introduce a parameter b that represents the "cost" of buffer occupancy by Type 2 traffic. Since buffer space is limited and shared, a queued Type 2 packet means that a buffer position is not available for storing a Type 1 packet; to discourage the Type 2 connection from hogging the buffer, the cost parameter b is introduced, while a reward for each Type 2 packet coming into the buffer encourages the Type 2 connection to transmit at a high rate.
Using standard on-off models for the Type 1 sources, we show how values can be assigned to the parameter b; the value depends on the characteristics of the Type 1 connection passing through the node, i.e., whether it is a Variable Bit Rate (VBR) video connection or a Continuous Bit Rate (CBR) connection etc. Our approach gives concrete networking significance to the parameter b, which has long been considered as an abstract parameter in reward-penalty formulations of flow control problems (for example, [Stidham '85]).
Having seen how to assign values to b, we focus on the Type 2 connection next. Since Type 2 connections do not have strict performance requirements, it is possible to defer transmitting a Type 2 packet, if the conditions downstream so warrant. This leads to the question: what is the "best" transmission policy for Type 2 packets? Decisions to transmit or not must be based on congestion conditions downstream; however, the network state that is available at any instant gives information that is old, since feedback latency is an inherent feature of high speed networks. Thus the problem is to identify the best transmission policy under delayed feedback information.
We study this problem in the framework of Markov Decision Theory. With appropriate assumptions on the arrivals, service times and scheduling discipline at a network node, we formulate our problem as a Partially Observable Controlled Markov Chain (PO-CMC). We then give an equivalent formulation of the problem in terms of a Completely Observable Controlled Markov Chain (CO-CMC) that is easier to deal with., Using Dynamic Programming and Value Iteration, we identify structural properties of an optimal transmission policy when the delay in obtaining feedback information is one time slot. For both discounted and average cost criteria, we show that the optimal policy has a two-threshold structure, with the threshold on the observed queue length depending, on whether a Type 2 packet was transmitted in the last slot or not.
For an observation delay k > 2, the Value Iteration technique does not yield results. We use the structure of the problem to provide computable upper and lower bounds to the optimal value function. A study of these bounds yields information about the structure of the optimal policy for this problem. We show that for appropriate values of the parameters of the problem, depending on the number of transmissions in the last k steps, there is an "upper cut off" number which is a value such that if the observed queue length is greater than or equal to this number, the optimal action is to not transmit. Since the number of transmissions in the last k steps is between 0 and A: both inclusive, we have a stack of (k+1) upper cut off values. We conjecture that these (k + l) values axe thresholds and the optimal policy for this problem has a (k + l)-threshold structure.
So far it has been assumed that the parameters of the problem are known at the transmission control point. In reality, this is usually not known and changes over time. Thus, one needs an adaptive transmission policy that keeps track of and adjusts to changing network conditions. We show that the information structure in our problem admits a simple adaptive policy that performs reasonably well in a quasi-static traffic environment.
Up to this point, the models we have studied correspond to a single hop in a virtual connection. We consider the multiple hop problem next. A basic matter of interest here is whether one should have end to end or hop by hop controls. We develop a sample path approach to answer this question. It turns out that depending on the relative values of the b parameter in the transmitting node and its downstream neighbour, sometimes end to end controls are preferable while at other times hop by hop controls are preferable.
Finally, we consider a routing problem in a high speed network where feedback information is delayed, as usual. As before, we formulate the problem in the framework of Markov Decision Theory and apply Value Iteration to deduce structural properties of an optimal control policy. We show that for both discounted and average cost criteria, the optimal policy for an observation delay of one slot is Join the Shortest Expected Queue (JSEQ) - a natural and intuitively satisfactory extension of the well-known Join the Shortest Queue (JSQ) policy that is optimal when there is no feedback delay (see, for example, [Weber 78]). However, for an observation delay of more than one slot, we show that the JSEQ policy is not optimal. Determining the structure of the optimal policy for a delay k>2 appears to be very difficult using the Value Iteration approach; we explore some likely policies by simulation.
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Haley, Joshua J. "Integration of communication constraints into physiocomimetic swarms via placement of location based virtual particles." Honors in the Major Thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/392.
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This thesis describes a change to the Physiocomimetics Robotic Swarm Control framework that implements communication constraints into swarm behavior. These constraints are necessary to successfully implement theoretical applications in the real world. We describe the basic background of swarm robotics, the Physiocomimetics framework and methods that have attempted to implement communications constraints into robotic swarms. The Framework is changed by the inclusion of different virtual particles at a global and local scale that only cause a force on swarm elements if those elements are disconnected from a swarm network. The global particles introduced are a point of known connectivity and a global centroid of the swarm. The local particles introduced are the point of last connectivity and a local centroid. These particles are tested in various simulations and the results are discussed. The global particles are very effective at insuring the communication constraints of the swarm, but the local particles only have partial success. Additionally, some observations are made about swarm formations and the effect of the communication range used during swarm formation.B.S.P.E.
Bachelors
Engineering and Computer Science
Computer Engineering
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Karvonen, Niklas. "Activity recognition in resource-constrained pervasive systems." Licentiate thesis, Luleå tekniska universitet, Datavetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26136.
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There is an increasing need for personalised and context-aware services in our everyday lives and we rely on mobile and wearable devices to provide such services. Data collected from these devices includes important information about users’ movements, locations, physiological status, and environment. This data can be analysed in order to recognise users’ activities and thus provide contextual information for services. Such activity recognition is an important tool for personalising and adapting assistive services and thereby increasing the usefulness of them.This licentiate thesis focuses on three important aspects for activity recognition usingwearable, resource constrained, devices in pervasive services. Firstly, it is investigated how to perform activity recognition unobtrusively by using a single tri-axial accelerometer. This involves finding the best combination of sensor placement and machine learning algorithm for the activities to be recognized. The best overall placement was found to be on the wrist using the random forest algorithm for detecting Strong-Light, Free-Bound and Sudden-Sustained movement activities belonging to the Laban Effort Framework.Secondly, this thesis proposes a novel machine learning algorithm suitable for resource-constrained devices commonly found in wearable and pervasive systems. The proposed algorithm is computationally inexpensive, parallelizable, has a small memory footprint, and is suitable for implementation in hardware. Due to this, it can reduce battery usage, increase responsiveness, and also make it possible to distribute the machine learning task, which enables balancing computational costs against data traffic costs. The proposed algorithm is shown to have a comparable accuracy to that of more advanced machine learning algorithms mainly for datasets with two classes.Thirdly, activity recognition is applied in a personalised and pervasive service for im-proving health and wellbeing. Two monitoring prototypes and one coaching prototype were proposed for achieving positive behaviour change. The three prototypes were evaluated in a user workshop with 12 users aging between 20 and 60. Participants of the workshop believed that the proposed health and wellbeing app is something people are likely to use on a permanent basis.By applying results from this thesis, systems can be made more energy efficient andless obtrusive while still maintaining a high activity recognition accuracy. It also shows that pervasive and wearable systems using activity recognition have the potential of relieving some problems in health and wellbeing that society face today.Godkänd; 2015; 20151021 (nikkar); Nedanstående person kommer att hålla licentiatseminarium för avläggande av teknologie licentiatexamen. Namn: Niklas Karvonen Ämne: Distribuerade datorsystem/Pervasive Mobile Computing Uppsats: Activity Recognition in Resource-Constrained Pervasive Systems Examinator: Professor Kåre Synnes, Institutionen för system- och rymdteknik Avdelning: Datavetenskap, Luleå tekniska universitet Diskutant: Professor Chris Nugent, University of Ulster, Northern Ireland Tid: Tisdag 15 december 2015 kl 15.00 Plats: D770, Luleå tekniska universitet
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Johansen, Stian. "Rate-Distortion Optimization for Video Communication in Resource Constrained IP Networks." Doctoral thesis, Norwegian University of Science and Technology, Department of Electronics and Telecommunications, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-2014.
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Resource limitations lead to a number of challenges in all communication systems. This is also the case for video communication over networks based on the Internet Protocol (IP), where limited rates are shared among competing, heterogeneous users. Packet losses, delays and connectivity losses will be experienced to a varying degree depending on network loads, physical properties and mobility-related issues. These factors, as well as source coding characteristics, in source the visual quality experienced by the users.
One of the main contributions of the work presented in this thesis is that performance gains can be attained when considering characteristics of source coding, networks and congestion control jointly. Throughout the presented work, optimization of visual quality is at the centre of attention. The thesis is divided into three main parts, with contributions as follows.
Part A deals with rate-distortion optimized packet loss protection when communicating video over multiple channels simultaneously. Source coder characteristics and characteristics of the (logically or physically) different channels are taken into account in order to yield an optimized packet loss protection of the video. This part presents different optimization algorithms, which are in turncompared in terms of both performance and complexity.
Part B uses the algorithms of part A in the context of congestion control. Specifically, the potential problem of misbehaving receivers is considered. In current systems, there exists an incentive for non-conformant congestion control by video receivers in that an improved video quality can be achieved through obtaining an unfairly high bandwidth share. Since this has unfortunate effects on the connection characteristics of competing users, it poses a potential problem for mass deployment of UDP (User Datagram Protocol) based video services. In this work, a joint source-channel coding based framework which removes the incentive for bandwidth `greediness' is introduced. Specifically, the framework attempts to reverse the situation and provide an incentive in terms of visual quality for adhering to congestion control guidelines for fair bandwidth sharing. The framework is developed for both unicast and multicast cases, and is presented along with optimization algorithms and simulation results.
Part C considers real-time video delivery in mobile ad-hoc networks. As this type of networks exhibit rather harsh characteristics in terms of throughput, packet losses and mobility-induced route losses, new solutions are required. The approach taken in this work is based on a distributed rate-distortion optimization framework, where multiple sources are used concurrently. The system uses scalable video coding and rateless channel codes in order to allow for uncoordinated sources and distributed optimization. The complete system is implemented in a network simulator, and is shown to exhibit considerable performance gains compared to previous proposed systems.
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Joubert, Yvonne Trijntje. "Organisation team sport interventions to minimise diversity constraints in the workplace." Diss., University of Pretoria, 2010. http://hdl.handle.net/2263/30564.
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The main aim of this study is to explore and determine the effect of an organisation team sport intervention on a number of diversity constraints in two financial organisations. The diversity constraints relevant in this study are race, ethnicity, generation gaps, gender, sexual orientation, socioeconomic status, age, physical abilities, religious beliefs, political beliefs, parental status, education and income. The main aim is to determine whether organisation team sport interventions impacted on the participating employees’ relationships, trust and respect towards one another, despite their differences in culture, age, gender and religion. The study was conducted among 26 employees of the two financial organisations that participate in organisation team sport. The data were collected by means of focus group interviews and individual interviews. The results indicated that a strong bond is established between employees in the organisation during organisation team sport. Employees are encouraged to share information, which leads to increased productivity. Business relationships can be created whilst talking sport, attending sport events or playing sport. The conclusions was made that organisation team sport is therefore a vehicle for creating opportunities to share goals and visions, improving individual commitment, improving cohesion, increasing trust and respect in a workforce, improving communication between employees and enhancing employees’ knowledge of other employees. The contributions that organisation team sport makes to an organisation are all requirements for effective diversity management in the workplace. Copyright 2010, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. Please cite as follows: Joubert, YT 2010, Organisation team sport interventions to minimise diversity constraints in the workplace, MCom dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-02222012-111732 / > C12/4/194/gmDissertation (MCom)--University of Pretoria, 2010.
Human Resource Management
unrestricted
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Turman-Bryant, Phillip Nicholas. "Closing the Loop: the Capacities and Constraints of Information and Communication Technologies for Development (ICT4D)." PDXScholar, 2019. https://pdxscholar.library.pdx.edu/open_access_etds/5003.
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As a mechanism for collecting and sharing information, information and communications technologies (ICT) hold immense potential for individuals and institutions in low- and middle-income countries. Currently the distribution and adoption of ICTs--particularly mobile devices--has far outpaced the provision of other household services like clean water, sanitation, hygiene, or energy services. At the same time, the development and deployment of Internet of Things (IoT) devices including cellular- and satellite-connected sensors is facilitating more rapid feedback from remote regions where basic services are most limited. When used in conjunction with economic development or public health interventions, these devices and the feedback they provide can inform operation and maintenance activities for field staff and improve the monitoring and evaluation of outcomes for project stakeholders.
This dissertation includes three chapters written as journal articles. While each chapter is framed around the work and research efforts being undertaken by the Sustainable Water, Energy, and Environmental Technologies Lab (SweetLab) at Portland State University, the common thread that weaves all three investigations together is the theme of ICT-enabled programmatic feedback. The first chapter introduces the three theoretical lenses that inform these investigations and the ways that ICTs and the data they provide can (1) serve as more appropriate proxies for measuring access to services, (2) reduce information asymmetries between various stakeholders including communities, governments, implementers, and funders, and (3) enable more robust methodologies for measuring outcomes and impacts of interventions within complex adaptive systems. The second chapter presents a critical review of the methodologies and technologies being used to track progress on sanitation and hygiene development goals. Chapter three describes how simple sensors and weight measurements can be combined with complex machine learning algorithms to facilitate more reliable and cost-effective latrine servicing in informal settlements. Chapter four presents the results from an investigation exploring how near-time feedback from sensors installed on motorized boreholes can improve water service delivery and drought resilience in arid regions of Northern Kenya. Finally, chapter five provides a summary of the three manuscripts and discusses the significance of this research for future investigations.
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Swenberg, Thorbjörn. "Postproduction Agents : Audiovisual Design and Contemporary Constraints for Creativity." Licentiate thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-14083.
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Moving images and sounds are processed creatively after they have been recorded or computer generated. These processes consists of design activities carried out by workers that hold ‘agency’ through the crafts they exercise, because these crafts are defined by the Moving Image Industry and are employed in practically the same way regardless of company. This thesis explores what material constraints there are for such creativity in contemporary Swedish professional moving image postproduction. The central aspects concern digital material, workflow and design work as distributed activities. These aspects are coupled to production quality and efficiency at the postproduction companies where production takes place. The central concept developed in this thesis is ‘creative space’ which links quality and efficiency in moving image production to time for creativity, capacity of computer tools, user skills and constitution of digital moving image material. Creative spaces are inhabited by design agents, and might expand or shrink due to material factors. Those changes are coupled to parallel changes in quality and efficiency.Audiovisuella Medier
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Kang, Intae. "Topology control for broadcasting over energy constrained wireless ad hoc networks /." Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/6061.
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Deshpande, Milind Umesh. "Optimal video sensing strategy and performance analysis for wireless video sensors under delay constraints." Diss., Columbia, Mo. : University of Missouri-Columbia, 2005. http://hdl.handle.net/10355/5836.
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Thesis (M.S.)--University of Missouri-Columbia, 2005.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (July 17, 2006) Includes bibliographical references.
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Bernabo, Laurena Elizabeth Nelson. "Translating identity: norms and industrial constraints in adapting Glee for Latin America." Diss., University of Iowa, 2017. https://ir.uiowa.edu/etd/5416.
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This project analyzes the Spanish dubbing of Glee for Latin American audiences in order to understand how identity—gender, sexuality, race, ethnicity, religion, and (dis)ability—is shaped by the adaptation process. I make two primary interventions within the field of global television studies. First, I expand adaptation analysis by adding industrial norms and production processes to the traditional theorizations of technical and cultural aspects; secondly, I use this web of elements as an interpretive lens for analyzing television translations, thus providing a model for making sense of how the adaptation process affects the representation of race, sexuality, and other forms of identity. Glee is translated for all of Latin America by the Mexico City company New Art Dub, and so I spent three weeks there doing field work. In addition to interviewing Glee’s Spanish-language script writer, director, actors, engineers, and technicians, and observing their work at every stage, I reviewed dubbed scripts and conducted textual analysis of the dubbed episodes. As this project demonstrates, the translation process negotiates complex international forces along with numerous industrial, technical, and cultural constraints as it shapes representations of and discourses about sexual, gender, racial, and ethnic identities. This research demonstrates that between imperialism and indigenization is an entire adaptation industry which simultaneously exaggerates and downplays cross-cultural similarities and differences.
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Wernersson, Henrik Wernersson, and Yassin Atwa. "Resource constrained Industrial IoT device." Thesis, Högskolan i Halmstad, Akademin för informationsteknologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-31252.
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I dagens läge är industriella nätverk inte anpassade för att koppla upp resursbegränsade enheter pga av att industriella nätverks-protokollen som används är mer anpassade för real time applikationer. Det skulle vara ett stort steg för de industriella nätverken att kunna koppla upp resursbegränsade enheter för enkel övervakning samt analysering av data. Efter en undersökningsperiod av ett flertal olika IoT-protokoll, gjordes valet att implementera CoAP på en Anybus CompactCom-modul för testning. Under projektets gång användes det en del white-box testning i början vid implementationen av libCoAP. Efter att en fungerande implementation var gjord, påbörjades testning av input och output överensstämmelser med hjälp av black-box testning istället. Resultatet jämfördes i slutändan med den existerande lösningen att skicka parameterdata med hjälp av TCP. Resultatet hade en responstidsskillnad som var 92,3 % snabbare. Samtidigt tog det sammanlagt 24,2 % mindre plats i minnet (FLASH och RAM) för implementationen på Anybus CompactCom-modulen.
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Daum, Sebastian [Verfasser], and Fabian [Akademischer Betreuer] Kuhn. "The power of frequency hopping and information dissemination in constrained communication models." Freiburg : Universität, 2015. http://d-nb.info/1119247276/34.
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