Made available in DSpace on 2016-08-29T11:12:55Z (GMT). No. of bitstreams: 1 tese_4309_DISSERTAÇÃO - Tempo, path dependence e instabilidade - as convergências entre Keynes e Sraffa.pdf: 740150 bytes, checksum: 45037124a0591263a839cfa4822a5bd8 (MD5) Previous issue date: 2012-06-01 / TEMPO, PATH DEPENDENCE E INSTABILIDADE: AS CONVERGÊNCIAS ENTRE KEYNES E SRAFFA A dissertação analisa alguns tópicos convergentes nas teorias de Keynes e de Sraffa. Aborda a questão do tempo na teoria econômica e da path dependence na teoria neoclássica. Estuda o problema dos preços de produção e as condições para que eles funcionem como centros de gravidade. Através da Teoria Geral de Keynes, examina uma determinada forma de path dependence, aquela que diz respeito à influência das expectativas de curto prazo sobre as expectativas de longo prazo. Além disso, analisa como a teoria keynesiana trata dois temas específicos: um relacionado às flutuações endógenas da economia, e outro relacionado à instabilidade do processo econômico. Para tanto, utiliza, além da Teoria Geral, outros autores que trataram sobre o tema, como Harrod, Kregel e Setterfield. Por meio da teoria de Sraffa, mostra que não é possível formular um modelo com uma posição de equilíbrio de longo prazo. Tal fato resulta em instabilidade do processo econômico, em oposição à estabilidade gerada pelo modelo de crescimento de Solow. Por fim, trata sobre questões relacionadas à natureza do capital.

Trees are fundamental structures in computer science, being widely used in modeling and representing different types of data in numerous computer applications. In many cases, properties of objects being modeled are stored as weights or labels on the nodes of trees. Thus researchers have studied the preprocessing of weighted trees in which each node is assigned a weight, in order to support various path queries, for which a certain function over the weights of the nodes along a given query path in the tree is computed [3, 14, 22, 26]. In this thesis, we consider the problem of supporting several various path queries over a tree on n weighted nodes, where the weights are drawn from a set of σ distinct values. One query we support is the path median query, which asks for the median weight on a path between two given nodes. For this and the more general path selection query, we present a linear space data structure that answers queries in O(lg σ) time under the word RAM model. This greatly improves previous results on the same problem, as previous data structures achieving O(lg n) query time use O(n lg^2 n) space, and previous linear space data structures require O(n^ε) time to answer a query for any positive constant ε [26]. We also consider the path counting query and the path reporting query, where a path counting query asks for the number of nodes on a query path whose weights are in a query range, and a path reporting query requires to report these nodes. Our linear space data structure supports path counting queries with O(lg σ) query time. This matches the result of Chazelle [14] when σ is close to n, and has better performance when σ is significantly smaller than n. The same data structure can also support path reporting queries in O(lg σ + occ lg σ) time, where occ is the size of output. In addition, we present a data structure that answers path reporting queries in O(lg σ + occ lg lg σ) time, using O(n lg lg σ) words of space. These are the first data structures that answer path reporting queries.

Trees are fundamental structures in computer science, being widely used in modeling and representing different types of data in numerous computer applications. In many cases, properties of objects being modeled are stored as weights or labels on the nodes of trees. Thus researchers have studied the preprocessing of weighted trees in which each node is assigned a weight, in order to support various path queries, for which a certain function over the weights of the nodes along a given query path in the tree is computed [3, 14, 22, 26]. In this thesis, we consider the problem of supporting several various path queries over a tree on n weighted nodes, where the weights are drawn from a set of σ distinct values. One query we support is the path median query, which asks for the median weight on a path between two given nodes. For this and the more general path selection query, we present a linear space data structure that answers queries in O(lg σ) time under the word RAM model. This greatly improves previous results on the same problem, as previous data structures achieving O(lg n) query time use O(n lg^2 n) space, and previous linear space data structures require O(n^ε) time to answer a query for any positive constant ε [26]. We also consider the path counting query and the path reporting query, where a path counting query asks for the number of nodes on a query path whose weights are in a query range, and a path reporting query requires to report these nodes. Our linear space data structure supports path counting queries with O(lg σ) query time. This matches the result of Chazelle [14] when σ is close to n, and has better performance when σ is significantly smaller than n. The same data structure can also support path reporting queries in O(lg σ + occ lg σ) time, where occ is the size of output. In addition, we present a data structure that answers path reporting queries in O(lg σ + occ lg lg σ) time, using O(n lg lg σ) words of space. These are the first data structures that answer path reporting queries.

The current state of 3D path-planning leaves room for improvement. To navigate a 3D environment, techniques which were developed for 2D navigation are used and slightly adapted to generate convincing motion. However, these techniques often constrict the motion to a single plane. This constriction is not only a limitation, but also increases the error. We created a new method to compute a path in a 3D world without a planar constraint. We will discuss the computation of a Navigation Volume Network (NavNet), and how it finds a path. A NavNet is the 3D generalization of NavMeshes, and holds boundary and connection information which is utilized when planning a path for motion. Similar to how NavMeshes allow path-planning by simplifying the ground meshes, the NavNet simplifies the search space by approximating the 3D world through sampling. / Thesis / Master of Applied Science (MASc)

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面對通訊與資訊科技的大幅進步、網際網路的蓬勃發展、以及電信自由化帶來的激烈競爭，通訊網路正在進行一個巨大的變革，企圖將原有Circuit Switching 與 Packet Switching 網路整合成一個單一整合型網路－All-IP網路以支援所有的應用服務。All-IP網路受限於封包交換網路原有的特性，有服務品質問題(QoS)有待克服，因此有必要在All-IP網路上提供服務品質管理機制以實現整合型網路的目標。而要提供適當的QoS 管理，其成功之關鍵主要在於是否能提供一個簡單易行之架構。本論文先提出BBQ(Budget-Based QoS)採用以預算為基礎之服務品質管理，BBQ提供一個高適用性的管理架構和相關的管理工具，可適用於不同的下層網路架構和不同營運目標的網管政策。 而在本文中提出以路徑規劃(Path Planning)的方式作為此架構的路由方法。路徑規劃係以過去的歷史訊務資料為基礎，為未來可能進入網路中的訊務規劃出一組具有品質要求的路徑，而在系統運作時，只需根據訊務的需求，指定一條符合其品質要求的路徑即可。此方法不但可以給予進入網路的訊務絕對的服務品質保證，而且事前的運算可以免除在系統運作時大量的計算負擔。在本論文中，我們設計了一套路徑規劃的演算法，來驗證我們的方法之效能。而經過反覆的模擬測試，發現本路徑規劃方法的確較傳統OSPF演算法擁有較佳的網路效能，且可以提供進入網路的訊務較佳的服務品質保證。 / The advance in information technology and impact of telecommunications liberalization cause a revolution in commucation world. It attempt to merge circuit-switching and packet-switching network into one standlone perform. All-IP is one of those candidates. But All-IP also inherits the characteristics of packet-switching network, the problem of transmission quality. So, we need some management system of quality on All-IP network to achieve the ambition of converged network. In this thesis, we propose BBQ management system. BBQ offers a highly adaptive management architecture and some management tools for operators. Those tools can be used in different underly network layer and can be tuned by different network policy. We propose the path planning as routing approach in BBQ architecture. Path-planning is doing path calculation for the traffic may happen in future using the historic traffic statistic. In run-time, admission control component will assign a planned path that satisfy the requirements of admitted traffic. In this method, absolute transmission quality is guaranteed to admitted traffic. And pre-planning can reduce heavy calculation overhead in run-time. In this thesis, we design a path-planning algorithm, the GPPA algorithm, which takes pre-defined profit as its maximize objective under bandwidth and quality constraints. Through an performance evaluation using simulation method, we demonstrate that the path-planning might outperform the traditional OSPF algorithm.

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CTF3 is a test facility for a new CLIC high energy linear collider. For this beamsteering and beam focusing is vital. Because physically running a beamline and changingsetup is expensive and takes much effort it is beneficial to use a simulator for thebeamline. The transportation of the beam through the beamline can be representedwith matrix multiplications and for this reason MATLAB is a fitting environment tosimulate in. A Flight Path Simulator was written in MATLAB and was succefullyimplemented and tested for the CALIFES beamline of the two-beam test stand that ispart of the CTF3 facility.