Mobile robots are used for a wide range of purposes such as mapping an environment and transporting material goods. Regardless of the specific application, the navigation of the mobile robot is usually divided into three separate parts: localization, path planning and path execution. Localization is the process of determining the location of the robot with respect to a reference coordinate system. There are many different approaches to localizing a mobile robot which employ a wide variety of sensors. The objective of my research is to develop a method for the localization of multiple mobile robots equipped with inexpensive range sensors in an indoor environment. Each mobile robot will be equipped with a rotating infrared sensor and a rotating CMOS camera. The multiple mobile robot system will be treated as a linked robot for localization. The proposed localization method is verified via both simulation and experiment. Through the use of the virtual link length and relative heading information, a system of mobile robots can be effectively localized using detected environmental features.

Since the trial implementation of the ¡§Mini-Three-Links¡¨ policy in Kinmen on January 1, 2001, the government has in the past seven years adjusted relevant policies after step-by-step reviews based on the principle of promoting related matters in a sequential and orderly manner. The scale of the ¡§Mini-Three-Links¡¨ has expanded day by day, which has not only provided convenience to the lives of the people in Kinmen, but also provided convenient channels to the Taiwanese people traveling to and from the Mainland China. As of July 2008, the total number of people traveling across the Strait via the ¡§Mini-Three-Links¡¨ route has reached 1.586 million (both gross exit and gross entry) and the number of sailings via this route has reached 23,353.

This thesis considers several instances of abstraction that arose in the design and implementation of the web programming language Links. The first concerns user interfaces, specified using HTML forms. We wish to construct forms from existing form fragments without introducing dependencies on the implementation details of those fragments. Surprisingly, many existing web systems do not support this simple scenario. We present a library which captures the essence of form abstraction, and extend it with more practical facilities, such as validation of the HTML a program produces and of the input a user submits. An important part of our library is a simple semantics, given as the composition of three primitive “idioms”, an interface to computation introduced by McBride and Paterson. In order to justify this approach we present a comparison of idioms with the related notions of monads and arrows, refining the informal claims in the literature. Our library forms part of the Links framework for stateless web interactions. We describe a related aspect of this system, a preprocessor that derives generic instances of functions, which we use to serialise server state between client requests. The abstraction in this case involves the shape of datatypes: the serialisation operation is specified independently of the particular types involved. Our final instance of abstraction involves abstract types. Functional programming languages typically offer one of two styles of abstract type: the abstraction boundary may be drawn using a private data constructor, or using a type signature. We show that there is a pair of semantics-preserving translations between these two styles. In the light of this, we revisit the decision of the Haskell designers to offer the constructor style, and define a library that supports signature-style definitions in Haskell by translation into the constructor style.

This thesis considers the extent to which the hegemonic, socially and economically hierarchical principles of private enterprise were channelled through school-business links. School-business links take many forms, and the one I have highlighted is a neo-vocationalist programme which was aimed at rendering low-achieving senior secondary students 'employable'. In the process, the importance of private enterprise as generators of wealth is emphasised, while that of labour is overlooked. That is, the interests of employers are paramount in the programme, while those of the students are marginalised. In my discussion and conclusion, I find that the programme can be seen to be exploitative, because the rhetoric that legitimates it obscures the ways in which the interests of unequal social classes are met in an hierarchically differential fashion.

The problem of multicasting in wireless multihop networks was studied in this dissertation. Nodes in the multicast routing structures were classified into different classes based on their roles in the multicast routing structures. Optimal multicast routing strategies for different classes were analyzed using the most accurate interference model. Based on the analyses, two algorithms to create interference-aware multicast routing tree and three algorithms to create interference-aware multicast routing mesh were proposed. The proposed multicast routing structures were evaluated using wireless network simulations. To improve the credibility of the wireless network simulations, a frame-level bursty link model was proposed and implemented in ns-3 network simulator. The results showed that, by taking interference into account when building multicast routing structures, the proposed multicast routing structures provided improved performance over other multicast routing structures that do not consider wireless interference when building multicast routing structures.

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Thesis (M.S. in Computer Science) Naval Postgraduate School, June 1997. / Thesis advisor, Debra A. Hensgen. Includes bibliographical references (p. 267-268). Also available online.

Made available in DSpace on 2014-06-12T18:33:55Z (GMT). No. of bitstreams: 2 arquivo4023_1.pdf: 7829149 bytes, checksum: 5f2f6cea4642ac6e52f84df7f7792f19 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2008 / Diante da necessidade cada vez maior de usar a Internet por razões diversas, os indivíduos se deparam diariamente com gêneros digitais que precisam produzir ou compreender. Assim, buscamos investigar como se dá a percepção do hipertexto e refletir sobre possibilidades pedagógicas envolvendoo. Os questionamentos que nos guiaram foram referentes a: como os fatores idade, familiaridade com o computador e hábitos de leitura influenciam na compreensão do hipertexto; como a multissemiose e os links interferem nesse processamento e até que ponto os participantes estavam conscientes das estratégias utilizadas. Para encontrarmos as respostas a nossos questionamentos, utilizamos, com um grupo estudantes de inglês como língua estrangeira, em centro binacional do Recife, diversas atividades e questionários que versavam sobre leitura de diferentes páginas, bem como estratégias utilizadas. Nossas análises foram realizadas com o aporte teórico de teorias sobre ensinoaprendizagem de línguas (BROWN, 1994), a importância dos gêneros textuais para o trabalho de leitura (MARCUSCHI, 2000 E BRONCKART, 1999) e desenvolvimento de competências (DOLZ & SCHNEUWLY, 2004). Utilizamos ainda, concepções e modelos de leitura (VAN DIJK & KINTSCH, 1996, GOODMAN, 1994, RUDDELL, 1994, KLEIMAN, 2004), fizemos reflexões sobre Letramento Digital (SOARES, 2002, BRAGA, 2007) e noções de hipertexto e seus desafios cognitivos (MARCUSCHI, 2007; SANTAELA, 2004, XAVIER, 2002, dentre outros.). Os resultados evidenciaram que os links interferem bastante na compreensão e na tomada de decisões por parte dos leitores que demonstraram, muitas vezes, se perderem dependendo da organização das páginas. Demonstraram também que nem sempre os leitores, apesar de adultos, estão cientes que estratégia é o melhor auxílio de acordo com um determinado momento ou objetivo da leitura. Desse modo, a necessidade de se trabalhar o hipertexto, bem como as estratégias em sala de aula são urgentes e condizentes com uma metodologia de ensino de leitura atualizado e eficiente

Szemere´di’s Regularity Lemma [32, 33] is an important tool in combinatorics, with numerous appli- cations in combinatorial number theory, discrete geometry, extremal graph theory, and theoretical computer science. The Regularity Lemma hinges on the following concepts. Let G = (V, E) be a graph and let ∅ /= X, Y ⊂ V be a pair of disjoint vertex subsets. We define the density of the pair (X, Y ) by dG(X, Y ) = |E[X, Y ]|/(|X||Y |) where E[X, Y ] denotes the set of edges {x, y} ∈ E with x ∈ X and y ∈ Y . We say the pair (X, Y ) is ε-regular if all subsets XI ⊆ X and Y I ⊆ Y satisfying |XI| > ε|X| and |Y I| > ε|Y | also satisfy |dG(XI, Y I) − dG(X, Y )| < ε. The Regularity Lemma states that, for all ε > 0, all large n-vertex graphs G = (V, E) admit a partition V = V1 ∪ · · · ∪ Vt, where t = t(ε) depends on ε but not on n, so that all but εt2 pairs (Vi, Vj), 1 ≤ i < j ≤ t, are ε-regular. While Szemere´di’s original proof demonstrates the existence of such a partition, it gave no method for (efficiently) constructing such partitions. Alon, Duke, Lefmann, Ro¨dl, and Yuster [1, 2] showed that such partitions can be constructed in time O(M (n)), where M (n) is the time needed to multiply two n × n {0, 1}-matrices over the integers. Kohayakawa, Ro¨dl, and Thoma [17, 18] improved this time to O(n2). The Regularity Lemma can be extended to k-uniform hypergraphs, as can algorithmic for- mulations thereof. The most straightforward of these extends the concepts above to k-uniform hypergraphs H = (V, E) in a nearly verbatim way. Let ∅ /= X1, . . . , Xk ⊂ V be pairwise disjoint subsets, and let E[X1, . . . , Xk] denote the set of k-tuples {x1, . . . , xk} ∈ E satisfying x1 ∈ X1, . . . , xk ∈ Xk. We define the density of (X1, . . . , Xk) as dH(X1, . . . , Xk) = |E[X1, . . . , Xk]| / |X1| · · · |Xk|. We say that (X1, . . . , Xk) is ε-regular if all subsets XiI ⊆ Xi, 1 ≤ i ≤ k, satisfying |XiI| > ε|Xi| also satisfy |dH (X1I , . . . , XkI ) − dH (X1, . . . , Xk)| < ε. With these concepts, Szemeredi’s original proof can be applied to give that, for all integers k ≥ 2 and for all ε > 0, all n-vertex k-uniform hypergraphs H = (V, E) admit a partition V = V1 ∪· · ∪ Vt, where t = t(k, ε) is independent of n, so that all but εtk many k-tuples (Vi1 , . . . , Vik) are ε-regular, where 1 ≤ i1 < · · · < ik ≤ t. Czygrinow and Ro¨dl [4] gave an algorithm for such a regularity lemma, which in the context above, runs in time O(n2k−1 log5 n). In this dissertation, we consider regularity lemmas for 3-uniform hypergraphs. In this setting, our first main result improves the algorithm of Czygrinow and Ro¨dl to run in time O(n3), which is optimal in its order of magnitude. Our second main result shows that this algorithm gives a stronger notion of regularity than what is described above, where this stronger notion is described in the course of this dissertation. Finally, we discuss some ongoing applications of our constructive regularity lemmas to some classical algorithmic hypergraph problems.