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Dissertations / Theses on the topic 'Broadcast environment'
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1
Pereira, Manuela Alexandra Trigo Miranda de Sousa. "Video coding in a broadcast environment." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/62328.
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Thesis (M.S.)--Massachusetts Institute of Technology, Program in Media Arts & Sciences, 1993.Includes bibliographical references (leaves 79-81).
by Manuela Alexandra Trigo Miranda de Sousa Pereira.
M.S.
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Ho, Andrew Yin Fai. "Data indexing in heterogeneous multiple broadcast channels environment /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?COMP%202003%20HO.
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Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003.Includes bibliographical references (leaves 101-104). Also available in electronic version. Access restricted to campus users.
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Feinberg, David S. (David Scott) 1976. "Broadcast-based communication in a programming environment for novices." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/28388.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.Includes bibliographical references (p. 87-88).
This thesis proposes a model to make communication and processes in an object-oriented language accessible to novice programmers. For my thesis work, I developed a broadcast communication framework in the context of Scratch, an object-based programming language intended for children and being developed at the MIT Media Laboratory. Objects in this framework can broadcast events, which trigger other objects to start new processes. In this document, I identify the basic functionality required to support object communication in such a broadcast model, I describe my implementation of that functionality, and I consider the merits of various user interface metaphors to make these features accessible to novices. Finally, I compare the event broadcasting in this model with the use of procedures in more traditional programming languages, and raise questions as to whether the broadcast model's event handlers should supplement or supplant procedures in a beginner's programming language.
by David S. Feinberg.
M.Eng.
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Luh, William. "Collusion-resistant fingerprinting for multimedia in a broadcast channel environment." Texas A&M University, 2004. http://hdl.handle.net/1969.1/1478.
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Digital fingerprinting is a method by which a copyright owner can uniquely
embed a buyer-dependent, inconspicuous serial number (representing the fingerprint)
into every copy of digital data that is legally sold. The buyer of a legal copy is
then deterred from distributing further copies, because the unique fingerprint can be
used to trace back the origin of the piracy. The major challenge in fingerprinting is
collusion, an attack in which a coalition of pirates compare several of their uniquely
fingerprinted copies for the purpose of detecting and removing the fingerprints.
The objectives of this work are two-fold. First, we investigate the need for robustness
against large coalitions of pirates by introducing the concept of a malicious
distributor that has been overlooked in prior work. A novel fingerprinting code that
has superior codeword length in comparison to existing work under this novel malicious
distributor scenario is developed. In addition, ideas presented in the proposed
fingerprinting design can easily be applied to existing fingerprinting schemes, making
them more robust to collusion attacks.
Second, a new framework termed Joint Source Fingerprinting that integrates the
processes of watermarking and codebook design is introduced. The need for this new
paradigm is motivated by the fact that existing fingerprinting methods result in a
perceptually undistorted multimedia after collusion is applied. In contrast, the new
paradigm equates the process of collusion amongst a coalition of pirates, to degrading
the perceptual characteristics, and hence commercial value of the multimedia in question.
Thus by enforcing that the process of collusion diminishes the commercial value
of the content, the pirates are deterred from attacking the fingerprints. A fingerprinting
algorithm for video as well as an efficient means of broadcasting or distributing
fingerprinted video is also presented. Simulation results are provided to verify our
theoretical and empirical observations.
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Banik, Tuhin. "Spatial fading characteristics of VHF broadcast signals in an urban environment." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:8881/R/?func=dbin-jump-full&object_id=61679.
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Upchurch, Jeremy Eugene. "Religious Television and New Technologies: Managing Change in the Broadcast Environment." Thesis, University of North Texas, 2006. https://digital.library.unt.edu/ark:/67531/metadc5336/.
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This study examines the process of technological change in the religious television environment. The study also focuses on managerial response to said change. Through the use of a survey instrument, a quantitative examination is given, illustrating a managerial embrace of change principles, a positive attitude toward the idea of change, and a system of change behavior that matches several previously theorized change models. Also examined is how different station funding types correspond with types and rates of technological change, with the results reflecting that more funding sources for a station generally indicate a greater likelihood of technological change.
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Subramanian, Sivaramakrishnan. "Deterministic knowledge about nearby nodes in a mobile one dimensional environment." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1077.
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Chesters, Robert. "Packaging radio technology during the interwar period (1925-1939) : how did the rise in popularity of the wireless receiver introduce the modernist aesthetic to the British domestic environment?" Thesis, Loughborough University, 2014. https://dspace.lboro.ac.uk/2134/14781.
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This thesis aims to identify and explain how, through the consumption of the wireless as a modern consumer durable, modernism was brought to society. To understand this process, the study will map how social change during the period responded to wider intellectual and aesthetic currents and trends but was driven by emergent commercial, cultural and political economies of a newly mediated society. Furthermore, it seeks to establish that this happened not as a result of social engineering through model housing schemes but as a result of consumer-led demand. This investigation considers how, as part of that newly mediated social environment, the wireless developed following its arrival on the domestic market without having adopted a single stylistic form. It addresses how that form, both stylistically and technically, evolved over a relatively short period to address the economic and cultural requirements and expectations of a new electrically powered domestic entertainment technology. In so doing, a discourse will be established considering these expectations and requirements related to how the wireless in Britain adopted and adapted the Modernist design idiom. It will further consider how the language of Modernism was propagated as the accepted version of what a radio could or should look like, so developing the modernist paradigm in a broader sense. To gain an appreciation of this it is necessary to understand the contemporary public conception of what the modern was in a more general sense. To decipher this public perception of modernity the project aims to extrapolate that public conception through examining other popular forms and products. Although this suggests that Radio was not alone in adopting the language of the moderne, as a product it is notable for its widespread commercial success and as such can be identified as a significant carrier of the coded message of what was modern. Design historians such as Yagou and Forty have attempted to incorporate radio into various strands of historical perception but the typologies they have devised to describe and understand wireless fall short in addressing the relationship between modernity and the wireless and instead see the wireless in terms of being an independent consumer product, a quasi-scientific instrument or else a furnishing form, rather than creating categories which accommodate the wireless and its position as a design type in its own right. To overcome this shortcoming a strand of this thesis seeks to argue that the wireless was itself a proto-modernist device during the early years of market expansion. That device then developed along a natural stylistic course embracing contemporary decorative ideas. By assessing the response of radio manufacturers to the socio-economic conditions of their market, this study has highlighted how through producing a product which addressed contemporary ideas of glamour, ease of use and functionality, the wireless entered a wide range of homes during the 1920s and 1930s. For the public, the immediate appeal of the wireless was that it provided access to the international experience of listening in while simultaneously it provided a template for the consumer to base their understanding of the modern World, both in its mediated form and stylistic appearance. This thesis seeks to demonstrate that during the period 1925 to 1939, the wireless established itself as an unashamedly modern device which appealed to a broad socio economic cross section of the public. By consuming the wireless, the British public accepted a significant technological and stylistic aspect of modernity into their homes. This was achieved despite the privations of the era because of the perceived desirability of wireless broadcasts and the perception of listening in as a popular leisure activity. As a result of that consumer demand, the British public was given access to a range of stylistic versions of modernity through the design of radio cabinetry. These modern styles were readily consumed throughout the social spectrum in preference to historicist alternatives. This demonstrates that the wireless was instrumental in introducing the modernist aesthetic to the British domestic environment.
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Huang, Yan. "Efficient transaction processing in broadcast-based asymmetric communication environments." [Gainesville, Fla.] : University of Florida, 2001. http://purl.fcla.edu/fcla/etd/UFE0000323.
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Thesis (Ph. D.)--University of Florida, 2001.Title from title page of source document. Document formatted into pages; contains xvi, 186 p.; also contains graphics. Includes vita. Includes bibliographical references.
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Boczkowski, Lucas. "Search and broadcast in stochastic environments, a biological perspective." Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCC044.
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Cette thèse s’articule autour de deux séries de travaux motivés par des expériences sur des fourmis. Bien qu’inspirés par labiologie, les modèles que nous développons utilisent une terminologie et une approche typique de l’informatique théorique.Le premier modèle s’inspire du transport collaboratif de nourriture au sein de l’espèce P. Longicornis. Certains aspectsfondamentaux du processus peuvent être décrits par un problème de recherche sur un graphe en présence d’un certain typed’indications bruitées à chaque noeud. Ces indications représentent de courtes traces de phéromones déposées devant l’objettransporté afin de faciliter la navigation. Dans cette thèse, nous donnons une analyse complète du problème lorsque le graphesous-jacent est un arbre, une hypothèse pertinente dans un cadre informatique. En particulier, notre modèle peut être vucomme une généralisation de la recherche binaire aux arbres, en présence de bruit. De manière surprenante, lescomportements des algorithmes optimaux dans ce cadre diffèrent suivant le type de garantie que l’on étudie : convergence enmoyenne ou avec grande probabilité.Le deuxième modèle présenté dans cette thèse a été conçu pour décrire la dissémination d’informations au sein de fourmis dudésert. Dans notre modèle, les échanges ont lieu uniformément au hasard, et sont sujets à du bruit. Nous prouvons une borneinférieure sur le nombre d’interactions requis en fonction de la taille du groupe. La borne, de même que les hypothèses dumodèle, semblent compatible avec les données expérimentales.Une conséquence théorique de ce résultat est une séparation dans ce cadre des variantes PUSH et PULL pour le problème du broadcast avec bruit. Nous étudions aussi une version du problème avec des garanties de convergence plus fortes. Dans cecas, le problème peut-être résolu efficacement, même si les échanges d’information au cours de chaque interaction sont très limitésThis thesis is built around two series of works, each motivated by experiments on ants. We derive and analyse new models,that use computer science concepts and methodology, despite their biological roots and motivation.The first model studied in this thesis takes its inspiration in collaborative transport of food in the P. Longicornis species. Wefind that some key aspects of the process are well described by a graph search problem with noisy advice. The advicecorresponds to characteristic short scent marks laid in front of the load in order to facilitate its navigation. In this thesis, weprovide detailed analysis of the model on trees, which are relevant graph structures from a computer science standpoint. Inparticular our model may be viewed as a noisy extension of binary search to trees. Tight results in expectation and highprobability are derived with matching upper and lower bounds. Interestingly, there is a sharp phase transition phenomenon forthe expected runtime, but not when the algorithms are only required to succeed with high probability.The second model we work with was initially designed to capture information broadcast amongst desert ants. The model usesa stochastic meeting pattern and noise in the interactions, in a way that matches experimental data. Within this theoreticalmodel, we present in this document a strong lower bound on the number of interactions required before information can bespread reliably. Experimentally, we see that the time required for the recruitment process of even few ants increases sharplywith the group size, in accordance with our result. A theoretical consequence of the lower bound is a separation between theuniform noisy PUSH and PULL models of interaction. We also study a close variant of broadcast, without noise this time butunder more strict convergence requirements and show that in this case, the problem can be solved efficiently, even with verylimited exchange of information on each interaction
11
Arumugam, Rajkumar. "SCRIBE self-organized contention and routing in intelligent broadcast environments /." Cincinnati, Ohio : University of Cincinnati, 2002. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=ucin1024331160.
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ARUMUGAM, RAJKUMAR. "SCRIBE: SELF-ORGANIZED CONTENTION AND ROUTING IN INTELLIGENT BROADCAST ENVIRONMENTS." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1024331160.
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Chan, Yew Meng. "Processing mobile read-only transactions in broadcast environments with group consistency /." access full-text access abstract and table of contents, 2005. http://libweb.cityu.edu.hk/cgi-bin/ezdb/thesis.pl?mphil-cs-b19887504a.pdf.
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Thesis (M.Phil.)--City University of Hong Kong, 2005."Submitted to Department of Computer Science in partial fulfillment of the requirements for the degree of Master of Philosophy" Includes bibliographical references (leaves 98-102)
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Scotty, Stephen D. "Expected performance of the Global Broadcast Service (GBS), Phase II, with emphasis on environmental limitations to supportable data rates." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1997. http://handle.dtic.mil/100.2/ADA331511.
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Thesis (M.S. in System Technology (Scientific and Technical Intelligence)) Naval Postgraduate School, June 1997.Thesis advisor(s): Paul H. Moose and Tri T. Ha. "June 1997." Includes bibliographical references (p. 83-84). Also available in print.
15
Bjelm, Petter, and Mark Wibom. "Live Video Exploration - Exploring environments using live video, mobile devices and unacquainted users." Thesis, Malmö högskola, Fakulteten för kultur och samhälle (KS), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-23385.
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The live video streaming market is, as some research suggests, a difficult one to develop.Comparing it to other media it has the disadvantage of being available during a limitedperiod of time. This thesis explores how mobile devices can be used as an exploratorytool through live video streaming. The opportunity of control in the moment is studiedand examined in this report. This research will suggest a mobile device platform in whichpeople can assist other people exploring new environments around the globe. It also triesto evaluate whether this exploring interaction can occur between unacquainted people andat the same time not be hindered by any language barriers. The motivation behind thissubject is the human need and curiosity of exploring new environments and places.The foundation of the research approach was based on interaction design principles andmethods. This created a chain of methods used with the intent of better understandingwhat is to be considered when designing for live video experiences focusing onenvironments. The process lead to important understandings and key aspects to beconsidered when designing live experiences focusing on environments. The results thatemerged, showed that the most important encouragement is; to be presented with anenvironment that includes novel elements. Furthermore, the results could also concludethat by giving access to directional controls, and some means of expressing appreciation,can help to influence and shape exploration with live video.
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Macy, Dylan V. "Climate Translators: Broadcast New's Contribution to the Political Divide over Climate Change in the United States." Scholarship @ Claremont, 2020. https://scholarship.claremont.edu/pitzer_theses/94.
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In many instances, television news is the primary outlet through which people gain knowledge on climate change. Both the perceived threat of climate change and American news media have grown politically divided since the 1980s. I make the argument that American news media influences the partisan divide over climate change. In addition to the political landscape of news media, focus on political events and figures in climate coverage further contributes to a partisan divide. Supporting these claims are research displaying how climate change news is processed in a partisan manner and a selection of three case study periods in which climate change coverage spiked among MSNBC, CNN, and Fox News in the last twenty years (2000-2019). I collected news footage from all three case studies using the online database archive.org. Using this footage, an accompanying documentary short was produced that focused on the Paris Climate Accord Withdrawal in 2017. Presented in the documentary and the three case study periods, Fox News held a consistently hands-off and dismissive tone towards climate change, while MSNBC and CNN implemented climate science into coverage while advocating for collective climate action. I report that media is selected and processed via partisanship among viewers; these case studies illustrate the ways in which news media drives the political divide on climate change. I conclude by offering some future ways climate coverage can be more unifying, such as more emphasis on the economic benefits of “a green economy” in news coverage.
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Yang, Wenpin, and 楊文斌. "Broadcast System Performance Improvement in Noisy Environment." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/45847996455741130057.
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碩士長榮大學
職業安全與衛生學系碩士班
99
This study is to conduct fire horn speaker of performance-improving designing approach, assisted with the software of theater sound simulation－Yamaha Sound System Simulator－designed by a Japanese corporation, YAMAHA, to probe into the noisy environment (such as air compressor room, etc) to help solving the ineffective receiving from speakers. Via the result of the live testing, we find the computed values of sound pressure of different setting distances under the functional formula set according to the Standard of Fire Safety Code 133 are higher than those actually gauged by sound level meter. Moreover, the distribution of the values of sound pressure simulated by Y-S3 also accord with those actually gauged of the curve of minimum sound pressure. This result provides the basis for the research of speaker performance-improving designing and also suggests that the values of sound pressure simulated by Y-S3 are conservative and referable in the following research. During the unwarned fire evacuation drill in small noisy environment, the personnel can clearly identify the human voices and alarming sirens issued by the emergency-broadcasting speakers if the comprehensive values (noises of targeting field and of speakers) of sound pressure lively gauged by the sound level meter is higher than the net sound pressure solely issued by the speakers within 6 dB. This research took a factory for experiment, by using Y-S3 to proceed with the performance improvement of the speakers, and the effects of the emergency broadcasting system are obviously promoted.
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Zeng, Guan-Ci, and 曾冠淇. "The Application of Message Broadcast in Teaching Environment." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/92384334189180147538.
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碩士國立臺北教育大學
資訊科學系碩士班
104
Students get school announcements by bulletin board and website. If they don't see announcements on bulletin board or website, announcements won't be known by them. In this thesis, an application of push technology and iBeacon will be implemented. When student's mobile device or notebook computer were installed Bluetooth 4.0 then they will receive iBeacon's broadcast packets in classroom, app sends student ID and iBeacon's identifier to server. Server check identification by student ID and know student's location by iBeacon's identifier. Server can push school announcements, message to students and broadcast messages of nearby classroom for student. Student can know school's messages. School can effectively broadcast messages to students.
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Chiu, Mai-lun, and 邱美倫. "Using A*Algorithm for Data Broadcast in Wireless Environment." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/37078853597994364702.
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碩士南華大學
資訊管理學研究所
93
Data Broadcasting is an efficient communication model when clients request data from a server in wireless environment. Data is delivered by a server downstream with a wide bandwidth. All clients keep listening to the broadcast channel and catch the data that interest them. The important issue of designing a proper broadcast schedule is to reduce the clients’ total access time. Most previous researches focused on a query just only include one data item, but not consider multiple data items are included in a query. In this paper, we propose an A* algorithm to the broadcast problem which consider the complex queries where a query include multiple data items. Experiential results show that our method outperforms the QEM algorithm [14] in access time.
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Lai, Yi-mien, and 賴意旻. "Broadcast Data Allocation in Wireless Environment Using Genetic Algorithms." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/60820608542725428246.
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碩士南華大學
資訊管理學研究所
93
Owing to rapid advances in wireless communications and technologies, more and more information systems use in wireless communications. Due to the characteristic of broadcasting, it can serve a large number of clients with limited bandwidth. Data allocation is the one issue of database broadcasting in wireless networks, considers a client’s query is follow a particular order and usually composed of multi data items, server allocates the sequence of broadcast data items will affect the client to accomplish his query, so how server allocates the data is very important. We solve this problem with genetic algorithms; the initial population and the mutation operator are design for this problem. The experiments show that our genetic algorithms with design for problem is outperforms than generic genetic algorithms that without design for problem.
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Earnshaw, Rae A., C. Flerackers, Reeth F. Van, G. Vanischem, and F. Alsema. "Creating Broadcast Interactive Drama in a Networked Virtual Environment." 2001. http://hdl.handle.net/10454/2357.
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Kang, Tan-Jen, and 康誕仁. "Construct and Improve Digital TV Broadcast Tuner Assurance Environment." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/34253949254936611878.
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碩士元智大學
資訊工程學系
97
The aim of this thesis is to implement an automatic test environment which conforms to contemporary test standards on DVB (Digital TV Broadcast) tuner. There are various types of test standards from different countries, and this study focuses on presenting processes and results by adopting several types of test standards. Results from this study can alleviate the deficiency existed in contemporary test standards and serve as the basis to test environment which can be implemented by users. The test tool used in this study is Visual C++ because it is an extensively adopted software tool and is highly compatible to other tools. Thus, using Visual C++ to implement the DVB tuner test environment is feasible to achieve the goal of this study.
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CHANG, CHIEN-HSIUNG, and 張建雄. "The Research on Multiple Query Broadcast in Wireless Environment." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/07414745755350632815.
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Chen, Yei-Churng, and 陳逸鴻. "Proxy/Relay Server With Network Coding In Broadcast Environment." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/5zd5c3.
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碩士國立中央大學
資訊工程研究所
97
Recently, the number of internet users increase quickly. The proxy/relay server popularly has being used in the internet. In traditional peer to peer transmission, it needs a long time when server needs to handle a lot of requests from clients. It may cause the requests have being out of time, and clients don''t need the data anymore. It means that the server can''t give service to all clients immediately .In this paper, we consider the throughput in broadcast environment to propose a method using network coding technique to reschedule the transmission sequences. Our simulation results show that our algorithm can reduce the average waiting time and raise the throughput when server has a lot of clients.
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Hsiao, Ju-chin, and 蕭如卿. "Using Quadratic Programming for Data Broadcast Scheduling in Wireless Environment." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/15920826705573313065.
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碩士南華大學
資訊管理學研究所
94
Wireless communication technology and mobile computing are experiencing rapid growth. Because of the inherent restrictions of wireless communication, such as bandwidth and energy restrictions, the broadcasting method is preferred. In this work we mainly focus on effective data scheduling for wireless broadcast to reduce the access time of mobile clients. In this paper, we propose a quadratic programming method for complex-query-based broadcasting. Experimental results show that our algorithm can construct a better scheduling than QEM method in total access time.
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Chen, Yi-Mei, and 陳怡玫. "Comparisons between Skyline Query Process Methods in Data Broadcast Environment." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/gtecqm.
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碩士國立臺北科技大學
資訊工程系所
103
Data broadcasting is an efficient way to disseminate information when services a lots of mobile clients in wireless mobile environment at the same time, there are also many researches talks about location based services using data broadcasting, including range query, nearest neighbors search, etc. The skyline search is one practical query in mul-ti-criterion local based services. The most important factor is the distance between object and the mobile clients, for the example, a mobile client may want to find the nearest res-taurant with the lowest price. In such a query, there are two kinds of attributes, spatial and non-special attributes. The values of non-spatial attributes are static to all the mobile clients, but the values of the spatial attributes are not the same to different mobile clients due to the locations of each mobile client. Therefore, the results of skyline search are not the same for different mobile clients at different places. In the schedule of the data broadcasting, using indexing could increase the effectiveness of query processing, but it may also increase the total query search time. However, without using indexing, the ef-fectiveness of query processing will decrease but the total query search time will decrease perhaps. In the paper, we will compare four kinds of skyline search methods in data broadcasting environment, AR* method、R* method、Voronoi method and Maybe List method，and the experiments show that using indexing the tuning time is less than without using index structures. However, without using index structures the latency is greater than using index structures.
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Hsu, Chih-Hao, and 許志浩. "Generating Broadcast Programs on Multiple Channels in the Wireless Environment." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/12560180080582695588.
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碩士國立清華大學
資訊工程學系
89
Abstract In a wireless environment, the bandwidth of the channels and the energy of the portable devices are limited. Data broadcast has become an excellent method for efficient data dissemination. In this thesis, we generate two different broadcast programs, called data-based method and index-based method, to minimize the average access time and the tuning time of broadcast programs on multiple channels. In data-based method, we determine the set of data items to be allocated in each channel to minimize the average access time. First, a minimal expected average access time of the broadcast data items is derived. The broadcast program is then generated, which minimizes the minimal expected average access time. In index-based method, we will mix data items and index information into multiple channels with the purpose of minimizing the average access time and the tuning time of broadcast programs. Simulation is performed to compare the performance of our approaches with other existing approaches. The experiments results show that our approaches outperform others.
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Lan, Kuo-jui, and 藍國瑞. "An Efficient Broadcast Data Scheduling Strategy in Wireless Multi-channel Environment." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/09103230316230821849.
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碩士國立雲林科技大學
電子與資訊工程研究所碩士班
91
Wireless will have been an important trend of information products in the future; therefore, most of the wire network information will be delivered to clients via wireless mode. However, the broadcasting is an excellent method for efficient information dissemination in a wireless network. Because of now the restriction of the wireless bandwidth, how to broadcast information more efficiently for minimizing the expected access time of users and to promote the usage of the wireless bandwidth are important issues. Many previous approaches assume that each client needs only one data page, but in some application areas, such as weather, stock quotes and traffic reports often need data from more than one page. In recent years, many strategies have been proposed for efficient broadcast data on multiple wireless channels. C.H.Ke has proposed the SNV (Set-based version-Non-overlap Version) strategy for query set broadcast scheduling in multiple channels. In the SNV strategy, the data pages of the same query set are put together as much as possible, and it tries to avoid scheduling two or more pages of one query data set at the same time slot of different channels. In order to minimize the expected access time of users and the waste of bandwidth, Ye-In Chang has proposed another strategy, the HVS (Hybrid Version of the Set-based) strategy. The HVS approach combines the page-based and set-based strategies, and to improve some disadvantages of SNV strategy. However, there are three disadvantages with the previous approaches: (1) they still can not guarantee that there will be no conflict between data pages, which will result in long access time for the whole query set; (2) all query sets are arranged to the available channels in a round-robin pattern, which will also result in long access time for the whole query set; (3) the extension of the broadcast matrix may be unnecessary, which will result in a waste of bandwidth. Therefore, in this paper, we propose an efficient broadcast data scheduling strategy that consists of four rules, to improve these three above disadvantages. There are four rules with our approach: (1) Channel Selection �{ selects a available channel with a non-conflict empty slot whose position is near the head of the broadcast cycle as compared with other channels; (2) Conflict Avoidance �{ the pages of a query set must be placed on different time slot, which can guarantee that there will be no conflict between data pages; (3) Page Interchange �{ in order to reduce the probability of extensions of the broadcast matrix, we interchange positions of data pages that can be interchangeable without changing the access time for the whole query’s data set; (4) Column Interchange �{ this is for minimizing the access time of all query sets as much as possible. (5) Page Duplication − copy some pages from the end of the broadcast cycle to those empty slots which occur before those pages. Through our performance analysis and simulation, we show that our broadcast data scheduling strategy requires less total expected access time than the HVS strategy.
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Chen, Ming-Hui, and 陳銘輝. "A Data Broadcast Scheme Based on Prediction for The Wireless Environment." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/01966165138692595612.
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碩士國立中興大學
資訊科學研究所
90
Broadcasting is an essential paradigm to transport data and support scalability in the wireless environment. Traditional index-based broadcast schemes take advantage of tree structures for saving energy, but they record too much index information to make the broadcast cycle short. On the other hand, the hash scheme may suffer from longer broadcast cycles and data collision problems, resulting in longer access time and tuning time. In this study, we propose a novel broadcast scheme, named predictive indexing, which allows mobile clients to access data by predicting data locations in the broadcast cycle. The new scheme not only has very compact structure, but also is flexible enough to allow the server to adjust the index structure for saving energy or reducing access time. Experimental studies show that it outperforms the tree-based schemes 2.5 times in energy saving, while maintaining roughly the same access time. It also outperforms the flexible indexing 46% and the hash scheme 37%, respectively, in energy consumption.
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MAk, Che-Lun, and 麥哲綸. "A Study on KNN and RNN Searches in Multi-channel Broadcast Environment." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/2f8h4z.
Full textAbstract:
碩士國立臺北科技大學
資訊工程系研究所
100
Data broadcasting is an e ective way to disseminate information to a large amount of mobile clients in wireless mobile environments. Many information ser- vices can use such a technique to serve the clients, including Location-Based Service (LBS). K nearest neighbor (kNN) search and Reverse nearest neighbor (RNN) search are the two of the important location-based services. KNN search allows clients to get the points of interests around them, and RNN search is to determine a set of data points, where the query point is the nearest neighbor of each data point re- spectively, in a given data set. In this thesis, we consider to use multiple channels to broadcast the data, and provide several scheduling algorithms for multi-channel to compare with the ones for single channel using latency and tuning time as the measurements. In the proposed broadcast, we use some addition information in the broadcast data instead of an index to save the tuning time and latency. We farther discuss the tuning time and latency when di erent space- lling curves are applied in the schedules. Finally, we discuss the performance and present our ndings through a large number of experiments
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Huang, Yun-shian, and 黃雲賢. "Data Broadcasting with Deadline Based on Network Coding in On-demand Broadcast Environment." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/65891341543969549312.
Full textAbstract:
碩士南華大學
資訊管理學系碩士班
98
On-demand broadcast is an effective wireless data dissemination technique in data broadcast environment. In real world, users'' queries usually include multiple data items. Recently, there are many related papers began to explore multi-item queries of data scheduling. However, traditional on-demand data broadcast scheduling assume that each time slot includes only one data item. Therefore, the above constraint demands a mobile user to wait until the next broadcast cycle to retrieve the data item if he misses the item in the cycle. Using network coding technique, server can encode and broadcast multiple data items in a time slot. The data item was repeated allocated different positions in the broadcast cycle. A user can retrieve data items which they needed on the places in a broadcast cycle by using the user''s cached data items to decode it. In this paper, we based on network coding model and we propose a new weight metrics that decided which query should be service with the highest priority. The metrics considers the factor of requests deadline to reduce deadline miss rate. Experiment results show that our algorithm can increase 20% success rate (which only increase 5% user''s access time) compared with [3].
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Yang, Tzu-Hsien, and 楊子賢. "Broadcast Program Generation for Efficient Multiple Data Items Access in the Wireless Environment." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/68373672465106248104.
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Lin, Chien-Ju, and 林建儒. "Compression-aware Automatic Test Pattern Generationbased on Skew Insertion Technique in the Broadcast Environment." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/76672819554043854982.
Full textAbstract:
碩士臺灣大學
電機工程學研究所
98
As the advance of the technology and the design complexity increases, test compression techniques has become mandatory due to the growing test data volume and high ATE test cost. Several broadcast based technique has been proposed to address this issue by reordering the scan chains into an optimal structure. However, the reordering of the scan chains generally impact the timing and increases routing overhead. Skew insertion provides an alternative solution. By inserting skews in front of the scan chains to delay the value received, the test patterns become encodable in the broadcast environment. However, conventional methods usually manipulate on the pre generated test sets, thus the widely-adopted dynamic compaction technique cannot be utilized afterward to further increase the compression ratio. Moreover, if an encodable solution cannot be found, the additional topping serial pattern will greatly degrades the compression ratio. This thesis determines the encodable skew configuration during ATPG, so as to avoid the conflict assignment in an early stage. The core technology is the compression aware ATPG, and the partial serial technique is further proposed to alleviate the high linear dependency of the broadcast constraints. Effectiveness of the proposed technique is validated with ISCAS89 and ITC99 benchmark circuit. The proposed technique generally provide high data reduction ratio, and without the need of the reordering the scan chains.
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Tsai, Tsung-Ho, and 蔡宗和. "The Reserch of Broadcast Automation System,Encoding Technology and Tapeless Environment of Digital TV." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/ac3z9n.
Full textAbstract:
碩士國立臺北科技大學
光電與通訊產業研發碩士專班
95
For TV station, the final goal of digitization is simplifies internal workflow. By digitizing video and audio, we can have digit assets which have huge economic efficiency with the lowest cost to achieve the highest income. To achieve that in a competitive age like 21st centuries. Building tapeless environment is already urgent for TV station. The fully digitization of TV system is a project that involve a lot of technology(broadcast, television, and IT). At the same time, there are many technical problems still not solve. In the digitization process of television station workflow, the communication and integration between equipment have become a trend. Due to the demand is different that the television station produces and broadcast programs, they must rely on integrating digital images compressions format to achieve tapeless environment. This paper will direct the compression technologies which though this method will create a tapeless environment. The transmission bandwidth, storage content and the equipment conformity will be the key issue to this success.
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Peng, Jheng-Bao, and 彭鉦堡. "Broadcast Protocols Using Multipoint Relays And Fountain Codes for FH/TDMA Ad Hoc Networks Under Jamming Environment." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/47455653444654536099.
Full textAbstract:
碩士元智大學
通訊工程學系
99
This thesis mainly discusses the protocols for broadcasting through multihop multipoint relays in wireless ad hoc networks. A base station broadcasts packets, which are first fountain encoded, downlink to all ad hoc nodes through multipoint relays. For simplicity, the relays transmit their packets according to the schedule of FH/TDMA. We assume two jamming cases which cause packet damaged. One is block jamming and the other is bit jamming. Besides the well-known flooding protocol and the optimized link state routing (OLSR) protocol under block jamming, we propose a weighted link state routing protocol. Compared with the flooding protocol, the proposed protocol can effectively decrease the total number of retransmitted packets sent by the relays in the network. Compared with the OLSR protocol, the proposed protocol can effectively decrease the retransmission delay in average for all nodes in the network. Under bit jamming, we propose the concept of virtual link to achieve higher resisting ability to jamming and hence lower number of retransmitted packets in the network. Simulation results verify our proposed ideas which provide good performance in the wireless ad hoc network.
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Lotter, Theresa E. "An investigation into the sustainability of community radio. Campus radio as case-study." Diss., 2007. http://hdl.handle.net/2263/29567.
Full textAbstract:
There is a dearth of information on community radio in South Africa; although much attention has been given to the role of community radio in development, education and community representation, there has been very little focus on community radio’s functioning within South Africa’s current broadcast system. The researcher explored the viability of the current conception of community radio by means of a literature review, as well as an examination of the South African Advertising Research Foundation’s listener figures for community radio stations across South Africa. The researcher then investigated how conducive the present broadcasting climate is to the growth of this medium through the use of a campus radio station as case-study. Semi-structured interviews were held with the management staff of a campus radio station; a thematic analysis was then conducted on the completed interviews so as to extract the meanings inherent in the participant’s experience. As such, the question of whether community radio can continue to survive within South Africa’s three-tier system of broadcasting without a radical re-conceptualization of the broadcasting system itself, was addressed. The researcher explored what community radio gives to the world of broadcasting that commercial and public radio does not, and how these contributions can be compounded to ensure the long term sustainability of this medium. These arguments were then put forth in the creation of a hypothetical re-conceptualization of a new broadcasting system.Dissertation (M (Research Psychology))--University of Pretoria, 2007.
Psychology
M (Research Psychology)
unrestricted
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林政緯. "A multi-objective genetic algorithm for reducing access time and tuning time in broadcast scheduling of mobile computing environment." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/37829447960002473322.
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WU, TSUNG-YEH, and 吳宗曄. "The source credibility of the streamer, the impact of the live broadcast environment atmosphere on the audience's perceived value." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/23rsba.
Full textAbstract:
碩士國立臺北商業大學
企業管理系碩士班
106
With the advancement and innovation of network technology, live broadcast on the Internet is a new application technology, in which the growth rate of live video production has grown exponentially. Therefore, the company has driven the game live industry by e-sports and combining live broadcast technology. In the past, game makers have been endorsed by celebrities and celebrities, but with the trend,the Streamer has become the target of game makers' preference, and the Stream platform has become the target market for advertisers to advertise. In this study, whether audiences with different levels of involvement in the game have interference with source credibility, environmental atmosphere and perceived value, and whether perceived value generates willingness to purchase to understand the characteristics of the different audiences involved in the preferences of the live and how to make the audience interested in buying. Both studies in this study were distributed on non-random convenience sampling on PTT. Study 1 and Study 2 were casual and professional live subjects.The study found that the casual-type streamers has no interference with the influence of the attractiveness and environmental atmosphere on the perceived value of the audience with different levels of involvement;expertise-type streamers have no interference with the impact of professionalism on perceived value for audiences of different levels of involvement. The results provided by this research also contribute to the future development of the stream platform and how to increase the audience's adhesion, properly maintain the audience's involvement, and also have different suggestions for the live broadcast of the live, and use this research to expand the past. The lack of stream platform and streamers master research.
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Popescu, Adrian Daniel. "SLA-Aware Adaptive Data Broadcasting in Wireless Environments." Thesis, 2009. http://hdl.handle.net/1807/18981.
Full textAbstract:
In mobile and wireless networks, data broadcasting for popular data items enables the efficient utilization of the limited wireless bandwidth. However, efficient data scheduling schemes are needed to fully exploit the benefits of data broadcasting. Towards this goal, several broadcast scheduling policies have been proposed. These existing schemes have mostly focused on either minimizing response time, or drop rate, when requests are associated with hard deadlines.
The inherent inaccuracy of hard deadlines in a dynamic mobile environment motivated us to use Service Level Agreements (SLAs) where a user specifies the utility of data as a function of its arrival time. Moreover, SLAs provide the mobile user with an already familiar quality of service specification
from wired environments. Hence, in this
dissertation, we propose SAAB, an SLA-aware adaptive data broadcast scheduling policy for maximizing the system utility under SLA-based performance measures. To achieve this goal, SAAB considers both the
characteristics of disseminated data objects as well as the SLAs associated with them. Additionally, SAAB automatically adjusts to the system workload conditions which enables it to constantly outperform existing broadcast scheduling policies.
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Huang, Jiun-Long, and 黃俊龍. "Data Dissemination on Broadcast Environments." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/75739286397991645489.
Full textAbstract:
博士國立臺灣大學
電機工程學研究所
91
The advance in wireless communication enables users to access information systems anytime, anywhere, via various mobile devices such as notebooks, tablet PCs, personal digital assistants (PDAs) and GPRS-enabled cellular phones. Service providers are establishing a number of mobile services including weather forecasting, stock information dissemination, location-dependent query, route guidance and so on. To provide such services, researchers have encountered and are endeavoring to overcome challenges in related research areas, including mobile data management, wireless network infrastructure, location-dependent data management, and pervasive computing, to name a few. A mobile computing environment is in essence a distributed system. However, a computing environment is more challenging than a traditional distributed system due to the following characteristics: resource limited mobile devices, low network bandwidth, heterogeneity on mobile devices and user mobility. In recent years, data broadcast becomes a promising technique in a mobile computing environment. However, most prior works are under the premise that each user requests only one data item at a time and the requests for all data items are independent. However, in many real applications, some data items are semantically related and there exists dependency among the requests of these data items. Broadcast program generation algorithms assuming independent requests might not be able to effectively optimize the performance of the broadcast programs. This is the very problem we shall address in this dissertation. In addition to broadcast mode, channels can operate in on-demand mode in which a client explicitly sends data requests to retrieve the data items of interest. The major advantage of data broadcast is its scalability since the performance of the system does not depend on the number of clients listening to the broadcast channels. However, the performance degrades as the number of data items being broadcast increases. It has been shown that the combined use of the broadcast and on-demand channels can utilize bandwidth more efficiently. Hence, we also explore the problem of data and channel allocation to partition a given number of communication channels into broadcasting ones and on-demand ones. To address the problems resulting from the heterogeneity of various mobile devices, a proxy capable of transcoding (referred to as a transcoding proxy) is placed between a client and an information server to coordinate the mismatch between what the server provides and what the client prefers. Since proxy-based approaches are transparent to the content providers and users, this kind of approaches is able to simplify the design of servers and clients. However, most research works in transcoding proxies in mobile computing environments are under the traditional client-server architecture and do not employ the data broadcast technique. Hence, the transcoding proxies are not scalable and the network bandwidth is not well utilized. In addition, most prior studies do not consider the issue of quality of service (abbreviated as QoS) which is crucial in a mobile computing environment. In view of this, we design a scalable and QoS-aware transcoding proxy by utilizing the on-demand broadcasting technique to provide scalable and QoS-aware services.
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Juih-Sien, Chang. "An Approximation Algorithm for Synchronous Broadcast in Heterogeneous Environments." 2006. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2607200615484800.
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Chang, Juih-Sien, and 張瑞賢. "An Approximation Algorithm for Synchronous Broadcast in Heterogeneous Environments." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/04417714549624679831.
Full textAbstract:
碩士國立臺灣大學
資訊工程學研究所
94
Network of workstation (NOW) is a cost-effective alternative to massively parallel supercomputers. As commercially available off-the-shelf processors become cheaper and faster, it is now possible to build a PC or workstation cluster that provides high computing power within a limited budget. However, a cluster may consist of different types of processors and this heterogeneity within a cluster complicates the design of efficient collective communication protocols. This paper introduces a synchronous communication model where the communication cost is deter-mined by both sender and receiver. In this synchronous model both sender and receiver of a message must wait until the current communication finishes. Although this synchronous broadcast scheduling problem is NP-hard, we propose a greedy algorithm with a competitive ratio 3. The time complexity of the greedy algorithm is bounded by O(n log n) where n is the number of processors.
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Matsebula, Banele Brian, and Banele Brian Matsebula. "Continuous Range Skyline Query Processing in Data Broadcast Environments." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/25t6b9.
Full textAbstract:
碩士國立臺北科技大學
電資學院外國學生專班
103
A skyline query returns objects that are not dominated by any other object in the data set. There are several methods that can be used to compute snapshot skylines. These include branch and bound skyline (BBS), block nested loop (BNL), divide and conquer, bit-map and many oth- ers. Objects in day to day applications are dynamic and hence the skyline objects change with time. Snapshot queries do not meet these real world situations. Continuous queries return a set of results for a given time period. A client may require to find the skyline in a given range. Cur- rently, there are few works that look at this problem and it is only tackled in static data and the data broadcast is not considered. This work focuses on solving this problem by applying con- tinuous skyline query processing in data broadcast environments. The prediction of the objects future locations is the main problem. Objects in this problem should follow a defined model. The objects are indexed using TPR*-trees, which help predict future locations of the objects and then broadcast using breadth first search traversal (BFS) and depth first search traversal(DFS). Continuous range skyline - a batch method (CRS-B) access the broadcast channel and search for all objects which will intersect with query region in the duration of the query. After collecting all these objects, it then applies BNL algorithm to find the continuous results. On the other hand, online continuous range skyline - an online method (CRS-O) processes the results as it accesses relevant data from the broadcast channel. It reduces memory usage as it discards objects that will never be in the skyline set. Experiments also show that CRS-O performs well in DFS.
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Shu-Yu, Fu. "Different Types of Nearest Neighbor Searches in Wireless Broadcast Environments." 2006. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0006-1808200613420300.
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Fu, Shu-Yu, and 傅書煜. "Different Types of Nearest Neighbor Searches in Wireless Broadcast Environments." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/tmqxya.
Full textAbstract:
碩士國立臺北科技大學
資訊工程系所
94
Data broadcasting provides an effective way to disseminate information in the wireless mobile environment using the broadcast channel. Such a technology can be applied to many services, including the location-based service. In this thesis, we consider how to provide the k nearest neighbors (kNN) and the group k nearest neighbors (GkNN) queries using data broadcasting. We assume that the data is indexed by an R-tree. Due to the serializability of broadcast channels, adapting the previous proposed algorithms for kNN and GkNN searches to the broadcasting environment may result in a longer latency (time elapsed between issuing and termination of the query) and tuning time (the amount of time spent listening to the broadcast). By assuming a node in the R-tree corresponds to a packet in channel, we propose simple but efficient protocols for exact kNN and GkNN searches on a broadcast R-tree in terms of the tuning time, latency, and memory usage on the clients. We last validate the proposed protocols by extensive experiments.
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Wang, Yu-Ling, and 王玉玲. "KNN Search Protocols on Road Networks in Wireless Broadcast Environments." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/frfb8t.
Full textAbstract:
碩士國立臺北科技大學
資訊工程系研究所
103
In order to cope with the actual applications, many works related to location-based services (LBS) consider the real distance on road networks instead of the Euclidean distance between two data objects. Besides, data broadcast has been considered as an effective and secure approach to provide services to a large amount of users simultaneously. In this paper, the network Voronoi diagram used for partitioning the road networks and a tailor-made index are provided for the broadcast, so the tuning time can be effectively reduced. On the client side, we propose the corresponding query processes which use the properties on distance to prune the irrelevant data in order to reduce the tuning time. We then perform the simulation experiments using real data for analysis and discussion on the effectiveness of the proposed protocols. The experimental results show that our methods can have a less tuning time but pay for little longer latency in comparison with the other method.
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Ho, Kai-Yun, and 何凱云. "A Study on kNN Search Protocols in Wireless Broadcast Environments." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/wbhds3.
Full textAbstract:
碩士國立臺北科技大學
自動化科技研究所
96
Data broadcasting is an effective way to disseminate information to a large amount of mobile clients in wireless mobile environments. Many information services can use such a technique to serve the clients, including Location-Based Services (LBS). The k nearest neighbors (kNN) search is one of the important location-based services. With such a search, the clients can get the points of interests (POI’s) around them. In this thesis, we propose kNN search protocols using data broadcasting in wireless mobile environments for an arbitrary k >1. We consider how the server generates the broadcast schedule and how the client can efficiently execute the query process. Without using an index node in the broadcast, the proposed protocol uses some addition information for each broadcast data in order to save the tuning time. To reduce the latency, when scheduling the data points, we consider different space-filling curves in order to keep the data locality. The experimental results indicate our protocols can explore fewer data points, thus leading to a less tuning time and latency.
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Wang, Shuoi, and 王碩藝. "The Study of Improving Data Delivery in Multi-Channel Broadcast Environments." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/42088997448365410675.
Full textAbstract:
博士國立臺灣科技大學
資訊工程系
95
Abstract With the rapid development of wireless communication technology, mobile computing becomes possible. People with battery-limited mobile devices can access various kinds of information from anywhere at anytime. However, existing wireless services are limited by the constraints of mobile environments such as narrow bandwidth, frequent disconnections, and limited battery capacity. Data broadcast is an attractive approach in such context. Disseminating data through a broadcast channel allows simultaneous access by an unlimited number of mobile clients and thus allows efficient usage of scarce bandwidth. Sometimes the broadcast bandwidth is composed of multiple channels, where channels are allocated on discontinuous spectrums and can not be combined to a shared channel. The use of multiple channels allows better fault tolerance, configurability, and scalability. In this dissertation, we consider two issues arises in case multiple broadcast channels are present: i) how should the broadcast data be allocated to various channels, and ii) how should mobile clients surf the channels to obtain the data of interest. Access efficiency and energy conservation are two main performance issues in wireless broadcast system. Access efficiency concerns how fast a request is responded, and energy conservation concerns how to conserve a client’s battery power when it accesses the desired data. Efficient data accesses to multi-channel broadcast programs are motivated by the desire to satisfy client requirement efficiently with as little consumption of energy as possible. Cyclically broadcasting data over a channel is a basic scheduling approach called flat broadcast. When multiple channels are available, a data allocation scheme is needed to assign data to channels. Some channels may be reserved for those few frequently requested items, while the infrequently accessed bulk of data are allocated on other channels, this kind of allocation scheme called skewed allocation. In view of data access skew (the access probabilities of data items are usually different), in Chapter 3, we study the problem of broadcasting N data items over K channels assuming skewed data allocation and flat broadcast per channel, with the object of minimizing the average expected delay of the clients. The previously known DP algorithm is a straightforward dynamic programming implementation to partition data items and achieves an optimal solution with cost O(KN2). We propose a restricted dynamic programming (RDP) approach to achieve a similar performance to DP while with a much cheaper cost O(NlogK). Simulation results show that, the hit rate obtained by RDP is higher than 90% and it also outperforms similar work 200%. By using the curve fitting technique, we further refine RDP and develop an O(NlogNlogK) PKR algorithm; simulation results show that the solution is optimal In Chapter 4, we study fast access to data that are broadcast on multiple channels. If a client has not a priori knowledge of how data are allocated to them, in the worst case a client may have to scan all the channels before finding the desired data. We consider the access protocol and structure for making effective use of multiple channels. We propose adding index information to a skewed data allocation on a well-known index channel to help clients surf on data channels. Our solution consists of i) organizing data by popularity, which is done by PKR data allocation scheme; ii) organizing data by key, which is done by supplementing an index search tree for each data channel. Then nodes of all index trees are multiplexed onto a well-known index channel. Our method organizes data and index into a popularity hierarchy, thus the popular data and their indices are broadcast more frequently than less popular data and their indices. Simulation results show that the reduction of access time is on average about 48% over previous work with little tuning time overhead.
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Lin, Da-Jhong, and 林大中. "Query-Set-Based Scheduling of Data Broadcast in the Wireless Environments." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/80871368192500365098.
Full textAbstract:
碩士國立中興大學
資訊科學與工程學系
96
In the recent years, the applications of wireless technology have rapidly grown. There are more and more mobile users who obtain information with mobile devices (e.g., cell phone, or PDA) in their daily life. Broadcast is an efficient and scalable way of transmitting data to an unlimited number of mobile users. In order to cope with a huge amount of data access for satisfying all mobile users’ requests, data broadcast becomes popular and attracts researchers’ attention. One important issue in data broadcast is how to quickly service users’ request queries under the limited bandwidth of the wireless environment; therefore, researchers have focused on generating an optimal broadcast program to minimize the average access or expected delay time for all mobile users in a single or multiple channels environments. In this study, an equation of the optimal broadcast program with query-set replication is derived from the optimal broadcast program with data-item replication in a previous research. Then, a query-set-based scheduling algorithm, named QSBS, for producing broadcast program is proposed based on the concept of query-set replication. QSBS will make all data items in a query set be allocated in the same channel and be broadcast as near as possible. In this way, the average access time for all mobile users can be decreased. Finally, we implement QSBS and other broadcast-program scheduling algorithms, and conduct experiments to compare their performance.
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Hung, Jen-Jou, and 洪振洲. "Energy Efficient Data Access Schemes for Data Broadcast in Mobile Computing Environments." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/6ry9z8.
Full textAbstract:
博士國立臺灣科技大學
資訊管理系
94
Due to the limited power supply of mobile devices, much research has been done on reducing the power consumption in mobile computing environments. Since supporting indices on the broadcast data items can effectively reduce the power consumption of the mobile clients, most of the existing research on data broadcasting has focused on designing efficient indexing schemes. To further reduce the energy consumption, we propose in this thesis two novel approaches. In the first approach, we propose to cache indices on the mobile clients and use them to access the broadcast data items. To manage the cached indices, we propose two new cache management policies. The lower-level-index-first policy caches the index nodes that are at the lower level of the index tree, while the cut-plane-first policy caches the index nodes that belong to a cut-plane of the index tree. Through experiments, we compare the performance of the two proposed policies with some existing policies in terms of tuning time and access time. The experiments show that index caching significantly reduces the tuning time of a mobile client without increasing its access time. In terms of tuning time, the experiments show that, when the access pattern of a mobile client is not skew, the cut-plane-first policy outperforms the lower-level-index first policy, LRU and LRFU. When the mobile client has limited cache and high skew of data access, the lower-levelindex- first policy outperforms the cut-plane-first policy, LRU and LRFU. In terms of access time, the lower-level-index first policy always outperforms the cut-plane-first policy, LRU and LRFU. In second approach, we explore the efficient data re-access problem in data broadcast of a mobile computing environment with data caching. Data caching is used in data broadcast with the aim of reducing both access time and tuning time. For the cache data items of a mobile client to be useful, they need to remain consistent with the source data items in the server. When the data items are updated in the server, a mobile client needs to access the new content of its cached data items from the server. The operation to access the new content of a cached data item is called a re-access operation in this thesis. The re-access operation is time- and energy-consuming since a mobile client needs to tune in to the broadcast channel for the data item. In this thesis, we propose to uses the bucket id of a cached data item to speed up the reaccess operations. We call this approach the re-access scheme. We analyze the performance of the re-access scheme and validate the analysis results through experiments. The experiments show that the re-access scheme improves the performance of data caching by significantly reducing the tuning time in re-accessing a data item. The experiments also show that the proposed re-access scheme is especially effective when the query frequency on the mobile client is high or when the data update frequency on the server is low. Besides, the proposed re-access scheme is robustness in the sense that it allows the broadcast server to update its broadcast structure in data broadcasting.