Master's thesis deals with the micro-region Klánovice's forest and its surroundings on the eastern edge of the City Prague. This area has not been given comprehensive attention yet. The findings are based on a critical review of the humble written and archaeological sources relating to the concerned area. In addition, was made, analysis of archaeological excavation, which was carried out on the deserted village Hol and also geophysical survey from the same site. Based on the lessons learned to better classify and discuss the role of this area in the hinterland of high medieval Prague. Keywords: deserted village, Klánovice forest, Hol, geophysical survey, ceramics, agricultural margins land, high middle ages

Made available in DSpace on 2014-12-17T14:58:19Z (GMT). No. of bitstreams: 1 RaphaelSF_DISSERT.pdf: 3572126 bytes, checksum: c44c0bf716695541147f2e019fde49de (MD5) Previous issue date: 2013-04-12 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The growing demand in the use of hybrid composite materials makes it essential a better understanding of their behavior face of various design conditions, such as the presence of geometric discontinuities in the cross section of structural elements. This way, the purpose of this dissertation is a study of the mechanical response (strength and stiffness), modes (characteristics) of fracture and Residual Strength of an hybrid polymeric composite with and without a geometric discontinuity in its longitudinal section (with a reduction in the cross section) loaded by uniaxial tension. This geometric discontinuity is characterized by central holes of different diameters. The hybrid composite was fabricated as laminate (plate) and consisting of ortho-tereftalic polyester matrix reinforced by 04 outer layers of Jute fibers bidirectional fabrics and 01 central layer of E-glass bidirectional fabric. The laminate was industrially manufactured (Tecniplas Nordeste Ind?stria e Com?rcio Ltda.), obtained by the hand lay-up technique. Initially, a study of the volumetric density of the laminate was made in order to verify its use in lightweight structures. Also were performed comparative studies on the mechanical properties and fracture modes under the conditions of the specimens without the central hole and with the different holes. For evaluating the possible influence of the holes in the structural stability of the laminate, the Residual Strength of the composite was determined for each case of variation in hole diameter. As a complementary study, analyses of the macroscopic final fracture characteristic of the laminates were developed. The presence of the central hole of any sizes, negatively changed the ultimate tensile strength. Regarding the elastic modulus, moreover, the difference found between the specimens was within the range of tests displacement, showing the laminate stability related to the stiffness / A crescente demanda na utiliza??o dos materiais comp?sitos h?bridos torna imprescind?vel uma melhor compreens?o do seu comportamento frente ?s mais diversas condi??es de projeto, como a presen?a de descontinuidades geom?tricas nos elementos estruturais. Nesse sentido, a proposta desta disserta??o ? um estudo envolvendo a resposta mec?nica (resist?ncia e rigidez), os modos (caracter?sticas) da fratura e Resist?ncia Residual de um laminado comp?sito h?brido de matriz polim?rica com e sem presen?a de descontinuidade geom?trica em sua se??o longitudinal (com redu??o da se??o transversal), sob a a??o de tra??o uniaxial. Essa descontinuidade geom?trica ? caracterizada por furos centrais de diferentes di?metros. O laminado comp?sito h?brido foi confeccionado na forma de placa e composto por matriz poli?ster orto-tereft?lica refor?ada por 04 camadas externas de tecidos bidirecionais de fibras de juta e 01 camada central de tecidos bidirecionais de fibras de vidro-E. O laminado foi fabricado industrialmente (Tecniplas Nordeste Ind?stria e Com?rcio Ltda.), obtido atrav?s do processo de lamina??o manual (hand lay-up). Inicialmente, foi feito um estudo da densidade volum?trica do laminado, de modo a comprovar sua aplica??o em estruturas leves. Foram realizados estudos comparativos entre as propriedades mec?nicas nas condi??es dos corpos de prova sem o furo e com os diferentes di?metros do furo. Para a avalia??o de poss?vel influ?ncia da presen?a dos furos centrais na estabilidade estrutural do laminado, a Resist?ncia Residual foi determinada para cada caso de varia??o do di?metro do furo. Como estudo complementar, an?lises macrosc?picas da caracter?stica de fratura final dos laminados foram desenvolvidas. A presen?a do furo central, independente do di?metro, influiu de forma danosa, principalmente na resist?ncia ?ltima ? tra??o. Quanto ao m?dulo de elasticidade, por outro lado, a diferen?a encontrada entre os corpos de prova apresentou-se dentro da faixa da dispers?o dos ensaios, mostrando estabilidade com rela??o ? rigidez do laminado

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IEEE 802.11 wireless LANs operating in the infrastructure mode are extremely popular and have seen widespread deployment because of their convenience and cost efficiency. A large number of research studies have investigated the performance of DCF, the default MAC protocol in 802.11 WLANs. Previous studies have pointed out several performance problems caused by the interaction of DCF in infrastructure-based WLANs. This thesis addresses a few of these issues. In the first part of the thesis, we address the issue of head-of-line (HOL) blocking at the Access Point (AP) in infrastructure WLANs. We use a cooperative ARQ scheme to resolve the obstruction at the AP queue. We analytically study the performance of our scheme in a single cell IEEE 802.11 infrastructure WLAN under a TCP controlled file download scenario and validate our analysis by extensive simulations. Both analysis and simulation results show considerable increase in system throughput with the cooperative ARQ scheme. We further examine the delay performance of the ARQ scheme in the presence of both elastic TCP traffic and delay sensitive VoIP traffic. Simulations results show that our scheme decreases the delay in the downlink for VoIP packets significantly while simultaneously providing considerable gains in the TCP download throughput. Next, we propose a joint uplink/downlink opportunistic scheduling scheme for maximising system throughput in infrastructure WLANs. We first solve the uplink/downlink unfairness that exists in infrastructure WLANs by maintaining a separate queue and a backoff timer at the AP for each mobile station (STA). We also increase the system throughput by making the backoff timer a function of the channel gains. We analyse the I performance of our scheme under symmetric UDP traffic with i. i. d. channel conditions. Finally, we discuss several opportunistic scheduling policies which aim to increase the system throughput while satisfying certain Quality of Service (QoS) objectives. The standard IEEE 802.11 DCF protocol only offers best-effort services and does not provide any QoS guarantees. Providing QoS in 802.11 networks with time varying channel conditions has proven to be a challenge. We show by simulations that by an appropriate choice of the scheduling metric in our opportunistic scheduling scheme, different QOS objectives like maximizing weighted system sum throughput, minimum rate guarantees and throughput optimality can be attained.

Formal verification of programs can be done with the aid of an interactive theorem prover. The program to be verified is represented in an intermediate language representation inside the interactive theorem prover, after which statements and their proofs can be constructed. This is a process that can be automated to a high degree. This thesis presents a proof procedure to efficiently generate a theorem stating the weakest precondition for a program to terminate successfully in a state upon which a certain postcondition is placed. Specifically, the Poly/ML implementation of the SML metalanguage is used to generate a theorem in the HOL4 interactive theorem prover regarding the properties of a program written in BIR, an abstract intermediate representation of machine code used in the PROSPER project. / Bevis av säkerhetsegenskaper hos program genom formell verifiering kan göras med hjälp av interaktiva teorembevisare. Det program som skall verifieras representeras i en mellanliggande språkrepresentation inuti den interaktiva teorembevisaren, varefter påståenden kan konstrueras, som sedan bevisas. Detta är en process som kan automatiseras i hög grad. Här presenterar vi en metod för att effektivt skapa och bevisa ett teorem som visar sundheten hos den svagaste förutsättningen för att ett program avslutas framgångsrikt under ett givet postvillkor. Specifikt använder vi Poly/ML-implementationen av SML för att generera ett teorem i den interaktiva teorembevisaren HOL4 som beskriver egenskaper hos ett program i BIR, en abstrakt mellanrepresentation av maskinkod som används i PROSPER-projektet.

No / A review is carried out on the characterisation and algorithmic implementation of an extended product-form approximation, based on the principle of maximum entropy (ME), for a wide class of arbitrary finite capacity open queueing network models (QNMs) with service and space priorities. A single server finite capacity GE/GE/1/N queue with R (R>1) distinct priority classes, compound Poisson arrival processes (CPPs) with geometrically distributed batches and generalised exponential (GE) service times is analysed via entropy maximisation, subject to suitable GE-type queueing theoretic constraints, under preemptive resume (PR) and head-of-line (HOL) scheduling rules combined with complete buffer sharing (CBS) and partial buffer sharing (PBS) management schemes stipulating a sequence of buffer thresholds {N=(N1,¿,NR),0<Ni¿Ni¿1,i=2,¿,R}. The GE/GE/1/N queue is utilised, in conjunction with GE-type first two moment flow approximation formulae, as a cost-effective building block towards the establishment of a generic ME queue-by-queue decomposition algorithm for arbitrary open QNMs with space and service priorities under repetitive service blocking with random destination (RS-RD). Typical numerical results are included to illustrate the credibility of the ME algorithm against simulation for various network topologies and define experimentally pessimistic GE-type performance bounds. Remarks on the extensions of the ME algorithm to other types of blocking mechanisms, such as repetitive service blocking with fixed destination (RS-FD) and blocking-after-service (BAS), are included.