Made available in DSpace on 2014-06-12T18:08:34Z (GMT). No. of bitstreams: 2 arquivo8471_1.pdf: 3654827 bytes, checksum: d59767326858e76124cc69b9d7086a05 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2011 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Nesta dissertação, estudamos experimentalmente a dinâmica de um laser de diodo operando com uma cavidade ótica externa implementada numa configuração tipo anel. A cavidade externa tem um comprimento efetivo de 3 metros para uma oscilação ótica. A cavidade e composta por três espelhos que permitem um controle e caracterização dos modos de emissão. Verificou-se que os dois modos contrapropagantes funcionaram travados em frequência para valores de corrente abaixo do limiar do laser sem cavidade externa e apresentaram flutuações de baixa frequência acima deste valor. Instabilidades em função do alinhamento da cavidade e da corrente de bombeio também foram observadas. Um sistema de detecção de pulsos com características caoticas e duração na escala de nanosegundos foi montado com fotodetectores com respostas em frequências de 2 GHz. Séries numéricas destas pulsações foram estudadas em suas composições espectrais. Um tratamento das equaçõoes para a estabilidade de cavidades óticas foi realizado e a compara ção dos espectros de frequência dos modos não longitudinais observados apresenta concordância com os cálculos feitos. Modelos teóricos para a dinâmica dos pulsos, com equações de taxas e incluindo a competição dos modos foram tratados numericamente e comparados com os experimentos. A inclusão de efeitos de absorvedor saturável, devido as regiões da camada da junção diodo que não atige o limiar de amplificação, foi testada nos modelos teóricos. A dinâmica observada experimentalmente esta em concordancia com o modelo proposto

Darbo objektas – motyvai, skatinantys rinktis futbolą laisvalaikiu. Darbo metodai – mokslinės literatūros šaltinių analizė, anketinė apklausa, matematinė statistika. Darbo tikslas – nustatyti motyvus, skatinančius rinktis futbolą laisvalaikiu. Darbo uždaviniai : 1. Atskleisti laisvalaikio sampratą, tipus ir formas. 2. Apibrėžti motyvus ir motyvacijos teorijas, bei jų sampratas. 3. Apžvelgti futbolo masiškumą skatinančius projektus Lietuvoje. 4. Ištirti bei palyginti lietuvių ir užsieniečių mėgėjų motyvus, skatinančius rinktis futbolą laisvalaikiu. Išvados : Buvo ištirta ir palyginta lietuvių ir užsieniečių motyvacijos ypatumai renkantis futbolą laisvalaikiu. Nustatyta, jog užsieniečių motyvacija rinktis futbolą yra didesnė. Ištirta, jog : užsieniečiai žaisdami futbolą labiau mėgaujasi negu lietuviai. Užsieniečiams futbolas yra geresnis laisvalaikio praleidimo būdas nei lietuviams. Lietuvius futbolas labiau moko savidisciplinos negu užsieniečius. Lietuvius futbolas labiau negu užsieniečius moko atsakomybės bei darbo komandoje. Užsieniečiams futbolas yra didesnė šeimos tradicija nei lietuviams. Užsieniečių draugai labiau skatina rinktis futbolą nei lietuvių draugai. Užsieniečiams labiau gėda galutinai nebežaisti futbolo negu lietuviams. Užsieniečiai žaidžia futbolą dėl motyvo įtikti tiems, kurie tikisi iš jų, jog žaistų, labiau, nei to siekia lietuviai. Šiuo metu, remiantis LFF Masinio futbolo pristatymu (2013), galima teigti, jog 2012 metais masinio futbolo renginiuose... [toliau žr. visą tekstą] / Object– reasons which drives to choose football for leisure. Methods – scientific literature analysis, questioning survey, mathematical statistics. Goal – disclosure of motives which drives to choose football for leisure. Tasks : 1. Reveal conception of leisure, types and forms. 2. Provide reasons, motivation theories, and their concepts. 3. Review projects of football as active leisure in Lithuania. 4. Research and compare lithuanians and foreigners motivation peculiarities choosing football as a leisure. Conclusions : Research was done to compare motivation peculiarities choosing football for leisure of lithuanians and foreigners. Determined that motivation to choose football for leisure of foreigners is bigger. Research showed, that foreigners enjoy football more than lithuanians, that football for them is better way to spent free time than lithuanians. But football teaches more self-discipline, teamwork, and responsibility to lithunains than foreigners. For foreigners it is bigger as a family tradition and friends influence to choose football is bigger than for lithuanians. Foreigners feels more shame finally to stop plalying football than lithuanians and they are more motivated to play for those who are expecting them to play than lithuanians. At the moment, according to LFF grassroots football presentation(2013), I can conclude that in 2012 there were 52670 participants in grassroots football events. This number grows anually.

The project is aimed at testing the kernels of real-time OS within the HC08 platform. The RM, EDF and polled loop mechanisms are being compared as well as freely available FreeRSTOS and QP systems. The project also incorporates descriptions of techniques used in the development, obtaining and the implementation of test environments. The evaluation is based on the tests made within the HC08 platform and the knowledge gained from the programming for every individual type of real-time OS.

Chaotic dynamics produced by optical delay systems have interesting applications in telecommunications. Optical chaos can be used to transmit secretly, in real-time, a message between an emitter and a receiver. The noise-like appearance of chaos is used to conceal the message, and the synchronization of the receiver with the chaotic emitter is used to decode the message. This work focuses on the study of two crucial topics in the field of chaotic optical communications. The first topic is the synchronization of chaotic external-cavity laser diodes, which are among the most promising chaotic emitters for secure communications. It is shown that, for edge-emitting lasers, two drastically different synchronization regimes are possible. The regimes differ in terms of the delay time in the synchronization and in terms of the robustness of the synchronization with respect to parameter mismatches between the emitter and the receiver. In vertical-cavity surface-emitting lasers, the two linearly-polarized components of the electric field also exhibit isochronous and anticipating synchronization when the coupling between the lasers is isotropic. When the coupling is polarized, the linearly-polarized component that is parallel to the injected polarization tends to synchronize isochronously with the injected optical field, while the other component tends to be suppressed, but it can also be antisynchronized. The second topic is the analysis of time series produced by optical chaotic emitters subjected to a delayed feedback. First, we verify with experimental data that chaos produced by optical delay systems is highly complex. This high complexity is demonstrated by estimating chaos dimension and entropy from experimental time series and from models of optical delay systems. Second, by analyzing chaotic time series, it is shown that the value of the delay of a single-delay system can always be identified, independently of the type of system used and of its complexity. Unfortunately, an eavesdropper can use this information on the delay value to break the cryptosystem. We propose a new cryptosystem with two delayed feedback loops that increases the difficulty of the delay identification problem.