Experimental laws of cratering for hypervelocity impacts of spherical projectiles into thick target

It is shown in this paper that the laws of cratering in a thick target under hypervelocity impact by a spherical projectile can be approximately expressed by the so-called iso-deviation law and a 2/3 power law. Moreover, hypervelocity impact should be characterized by the isotropic expansion of a crater. In the special case, when the projectile and target are of the same material, the laws mentioned above reduce to the result of a semi-spherical crater and the energy criterion. Generally speaking, a semi-spherical crater and the energy criterion are both approximations, which only take projectile density and target strength into account, and can be used for a rough estimation on the order of magnitude. The inconsistency in various fitted power laws in the literature was also clarified and explained in the paper.

Projeto para a organização de dados automatizados em bancos de dados na Câmara dos Deputados : um estudo de caso

A desorganização de dados em bancos de dados automatizados implica em ineficiência operacional causada por redundâncias, inconsistências, baixo reuso, riscos informacionais, enfim, menor valor agregado da TI aos objetivos organizacionais. Apoiado por técnicas de gerenciamento de projetos, busca-se em um estudo de caso na Câmara dos Deputados a otimização da organização dos dados em bancos de dados automatizados.

光滑粒子动力学方法中粒子分布与数值稳定性分析

光滑粒子动力学(SPH)作为一种拉格朗日型无网格粒子方法,已经成功地应用于包括含多相流动界面以及移动边界的可压缩和不可压缩流体运动的研究中.通过对Poiseuille流动的深入研究,探索了SPH方法中粒子分布对计算精度的影响,揭示了一种因为粒子不规则分布而导致的数值不稳定现象.研究显示,这种数值不稳定性起源于SPH方法粒子近似过程中的不连续性.使用了一种新的粒子近似格式以确保SPH方法中粒子近似的连续性.计算结果表明,这种新的粒子近似格式对于规则和不规则的粒子分布都能得到稳定精度的结果.

Efficient methods for empirical tests of behavioral economics theories in laboratory and field experiments

In the quest for a descriptive theory of decision-making, the rational actor model in economics imposes rather unrealistic expectations and abilities on human decision makers. The further we move from idealized scenarios, such as perfectly competitive markets, and ambitiously extend the reach of the theory to describe everyday decision making situations, the less sense these assumptions make. Behavioural economics has instead proposed models based on assumptions that are more psychologically realistic, with the aim of gaining more precision and descriptive power. Increased psychological realism, however, comes at the cost of a greater number of parameters and model complexity. Now there are a plethora of models, based on different assumptions, applicable in differing contextual settings, and selecting the right model to use tends to be an ad-hoc process. In this thesis, we develop optimal experimental design methods and evaluate different behavioral theories against evidence from lab and field experiments.

We look at evidence from controlled laboratory experiments. Subjects are presented with choices between monetary gambles or lotteries. Different decision-making theories evaluate the choices differently and would make distinct predictions about the subjects' choices. Theories whose predictions are inconsistent with the actual choices can be systematically eliminated. Behavioural theories can have multiple parameters requiring complex experimental designs with a very large number of possible choice tests. This imposes computational and economic constraints on using classical experimental design methods. We develop a methodology of adaptive tests: Bayesian Rapid Optimal Adaptive Designs (BROAD) that sequentially chooses the "most informative" test at each stage, and based on the response updates its posterior beliefs over the theories, which informs the next most informative test to run. BROAD utilizes the Equivalent Class Edge Cutting (EC²) criteria to select tests. We prove that the EC² criteria is adaptively submodular, which allows us to prove theoretical guarantees against the Bayes-optimal testing sequence even in the presence of noisy responses. In simulated ground-truth experiments, we find that the EC² criteria recovers the true hypotheses with significantly fewer tests than more widely used criteria such as Information Gain and Generalized Binary Search. We show, theoretically as well as experimentally, that surprisingly these popular criteria can perform poorly in the presence of noise, or subject errors. Furthermore, we use the adaptive submodular property of EC² to implement an accelerated greedy version of BROAD which leads to orders of magnitude speedup over other methods.

We use BROAD to perform two experiments. First, we compare the main classes of theories for decision-making under risk, namely: expected value, prospect theory, constant relative risk aversion (CRRA) and moments models. Subjects are given an initial endowment, and sequentially presented choices between two lotteries, with the possibility of losses. The lotteries are selected using BROAD, and 57 subjects from Caltech and UCLA are incentivized by randomly realizing one of the lotteries chosen. Aggregate posterior probabilities over the theories show limited evidence in favour of CRRA and moments' models. Classifying the subjects into types showed that most subjects are described by prospect theory, followed by expected value. Adaptive experimental design raises the possibility that subjects could engage in strategic manipulation, i.e. subjects could mask their true preferences and choose differently in order to obtain more favourable tests in later rounds thereby increasing their payoffs. We pay close attention to this problem; strategic manipulation is ruled out since it is infeasible in practice, and also since we do not find any signatures of it in our data.

In the second experiment, we compare the main theories of time preference: exponential discounting, hyperbolic discounting, "present bias" models: quasi-hyperbolic (α, β) discounting and fixed cost discounting, and generalized-hyperbolic discounting. 40 subjects from UCLA were given choices between 2 options: a smaller but more immediate payoff versus a larger but later payoff. We found very limited evidence for present bias models and hyperbolic discounting, and most subjects were classified as generalized hyperbolic discounting types, followed by exponential discounting.

In these models the passage of time is linear. We instead consider a psychological model where the perception of time is subjective. We prove that when the biological (subjective) time is positively dependent, it gives rise to hyperbolic discounting and temporal choice inconsistency.

We also test the predictions of behavioral theories in the "wild". We pay attention to prospect theory, which emerged as the dominant theory in our lab experiments of risky choice. Loss aversion and reference dependence predicts that consumers will behave in a uniquely distinct way than the standard rational model predicts. Specifically, loss aversion predicts that when an item is being offered at a discount, the demand for it will be greater than that explained by its price elasticity. Even more importantly, when the item is no longer discounted, demand for its close substitute would increase excessively. We tested this prediction using a discrete choice model with loss-averse utility function on data from a large eCommerce retailer. Not only did we identify loss aversion, but we also found that the effect decreased with consumers' experience. We outline the policy implications that consumer loss aversion entails, and strategies for competitive pricing.

In future work, BROAD can be widely applicable for testing different behavioural models, e.g. in social preference and game theory, and in different contextual settings. Additional measurements beyond choice data, including biological measurements such as skin conductance, can be used to more rapidly eliminate hypothesis and speed up model comparison. Discrete choice models also provide a framework for testing behavioural models with field data, and encourage combined lab-field experiments.

A clínica psicanalítica das toxicomanias

Esta dissertação propõe investigar o fenômeno das toxicomanias como conseqüência do declínio da imago paterna na cultura atual. O estudo foi iniciado pelo cotejamento do tema na teoria de Sigmund Freud e pela interpretação de que a toxicomania é uma resposta à satisfação sexual recalcada. A pesquisa explorou ainda esse tema no ensino escrito e falado de Jacques Lacan. O uso abusivo de drogas promove um gozo auto-erótico que busca liberar o toxicômano de ter que lidar com os impasses da castração. Por tal motivo foi explorada a queda da operatividade do significante Nome-do-Pai na atualidade. Se o significante autentica o sujeito do inconsciente e opera como regulador de gozo, a ascensão do objeto a ao zênite social provoca efeitos decisivos sobre o sujeito: a inconsistência do Outro, a predominância do discurso da ciência e do capitalista, e a proliferação dos novos sintomas. Nesse sentido, a segunda clínica de Lacan, a chamada clínica borromeana, foi utilizada para interpretar os modos de gozo na contemporaneidade. O atendimento de um paciente psicótico que faz uso de drogas mostrou a importância de trabalhar o diagnóstico diferencial para orientar a direção do tratamento.

A degradação ambiental de bacias hidrográficas urbanas e as políticas públicas no Município de São Gonçalo/RJ

No presente trabalho, buscou-se identificar os conflitos de interesses existentes nos três níveis do poder executivo que dificultam a gestão integrada de políticas públicas voltadas para a recuperação ambiental dos rios urbanos, considerando-se, como área de estudo, o Município de São Gonçalo (RJ). A pesquisa exploratória consistiu em revisão bibliográfica e trabalho empírico. No referencial teórico de análise, abordou-se a formação do Estado brasileiro, as políticas públicas e as relações de poder entre os agentes na tomada de decisão e na administração da coisa pública. Através de revisão na literatura, levantou--se o contexto histórico da ocupação e da degradação dos rios de São Gonçalo e da Baixada Fluminense, os planos e projetos para o setor de saneamento da região, bem como se empreendeu a compilação das normas legais pertinentes à gestão do território, aos recursos hídricos e ao saneamento. O trabalho de campo consistiu em levantamento de dados sobre a degradação das bacias hidrográficas no Município de São Gonçalo e das inter-relações existentes nas políticas públicas referentes à Região Hidrográfica da Bacia da Baía de Guanabara, onde o município em comento se insere. O estudo do caso evidenciou que a degradação dos rios urbanos é resultante, entre outros fatores, da falta de articulação das três esferas de governo, da descontinuidade das ações públicas, de interesses políticos e financeiros desarticulados das demandas socioambientais, da falta de infraestrutura técnica e financeira dos municípios, da pouca participação social no planejamento e tomada de decisões face às relações desiguais de poder, além da inconsistência e desarticulação dos planos e projetos governamentais, a exemplo dos planos diretores de uso ocupação do solo. Conclui-se ser fundamental o fortalecimento dos comitês de bacia e das instituições que os integram, possibilitando a articulação entre as políticas públicas municipais e as do governo estadual e federal, em relação às condicionantes ambientais, bem como ao uso do solo e ao saneamento. A solução dos problemas relativos aos rios urbanos só será possível através da gestão integrada e participativa, envolvendo efetivamente os diferentes setores usuários da bacia hidrográfica. O controle social das ações é imprescindível para manter a coerência, a efetividade, a eficácia e a continuidade dos planos, projetos e políticas do Estado. Assim, poderá ser contido o processo contínuo de degradação ambiental, em particular, dos recursos hídricos em bacias urbanas como acontece no Município de São Gonçalo e em diversos outros municípios brasileiros. Espera-se que esse estudo contribua para o aprimoramento do conhecimento e de soluções no que concerne à morte iminente dos rios urbanos do país.

Anorexia: um sintoma contemporâneo

Esta dissertação propõe investigar o sintoma anoréxico na estrutura neurótica como um sintoma contemporâneo em consequência da baixa operatividade da função paterna e da incidência avassaladora do Desejo Materno. A pesquisa foi iniciada por um levantamento histórico-bibliográfico do jejum e da recusa alimentar ao longo da história, até o estabelecimento da anorexia como uma psicopatologia. Para dar sustentação ao eixo central desta Dissertação, a pesquisa explora o conceito de pai na Obra de Freud e no ensino de Lacan, investigando a baixa operatividade desta função e seus efeitos na formação do sintoma. O conceito de pulsão é explorado com o objetivo de compreender a anorexia como uma invasão pulsional no corpo decorrente da precária sustentação da armadura simbólica que a lei paterna insere. Deste modo, esta Dissertação expõe duas hipóteses centrais: a anorexia como uma manobra de separação, operação que a função paterna não inscreve devidamente e desta forma um recurso diante da hegemonia materna; e a anorexia como estragos que apontam a invasão da mortífera pulsão no corpo, decorrentes da presença avassaladora do Outro materno e da inconsistência da função paterna

Effect of beta-irradiation on photoluminescence of MOCVD grown GaN

The effect of beta particles interaction on the optical properties of MOCVD grown GaN is reported. A significant change in luminescence properties of GaN is observed after exposing the material with 0.6 MeV beta particles with low dose of 10(12) cm(-2). The results obtained from photoluminescence measurements of irradiated GaN samples in low dose are found contradictory to those reported in literature for samples irradiated with heavy dose (> 10(15) cm(-2)) of electron. An increase in intensity of yellow luminescence has been observed with increasing dose of beta particles which is in disagreement to the already reported results in literature for heavily irradiated samples. A model has been proposed to sort out this inconsistency. The increase in YL intensity at low dose is attributed to the increase in concentration of VGaON complex whereas production of non-radiative VGaON clusters is assumed to justify the decrease in YL intensity at high dose.

semantic oriented ontology cohesion metrics for ontology-based systems

Ontologies play a core role to provide shared knowledge models to semantic-driven applications targeted by Semantic Web. Ontology metrics become an important area because they can help ontology engineers to assess ontology and better control project management and development of ontology based systems, and therefore reduce the risk of project failures. In this paper, we propose a set of ontology cohesion metrics which focuses on measuring (possibly inconsistent) ontologies in the context of dynamic and changing Web. They are: Number of Ontology Partitions (NOP), Number of Minimally Inconsistent Subsets (NMIS) and Average Value of Axiom Inconsistencies (AVAI). These ontology metrics are used to measure ontological semantics rather than ontological structure. They are theoretically validated for ensuring their theoretical soundness, and further empirically validated by a standard test set of debugging ontologies. The related algorithms to compute these ontology metrics also are discussed. These metrics proposed in this paper can be used as a very useful complementarity of existing ontology cohesion metrics.

An improved BP algorithm for pattern recognition

An improved BP algorithm for pattern recognition is proposed in this paper. By a function substitution for error measure, it resolves the inconsistency of BP algorithm for pattern recognition problems, i.e. the quadratic error is not sensitive to whether the training pattern is recognized correctly or not. Trained by this new method, the computer simulation result shows that the convergence speed is increased to treble and performance of the network is better than conventional BP algorithm with momentum and adaptive step size.

语义Web中描述逻辑本体的可伸缩推理和非一致处理

随着Web信息的与日俱增，使用机器处理这种信息成为一种必然的趋势。语义Web应运而生，成为当前研究的热点之一。它以本体为核心，为不同领域提供共享的词汇，以便机器处理Web信息。表达本体的标准语言OWL以描述逻辑为基础。OWL本体的推理可伸缩性差，难以适应规模较大的本体应用，因此推理可伸缩性问题是一个重要的实际问题。此外，OWL本体是一个逻辑系统，在生成、维护和集成等过程中，都很容易出现非一致现象，导致标准的推理机制不能正常运作。因此本体非一致问题是另一个重要的实际问题。针对上述两个实际问题，本文分别在实现可伸缩推理、修复非一致本体、以及进行非一致容忍推理三个方面提出了解决办法。 [可伸缩推理方面] 本文提出了一种本体断言公理集的划分方法，使本体推理能够在独立的划分子集中进行，以此提高本体推理的可伸缩性。 [本体修复方面] 本文提出了一种计算具有最小删除代价的本体子集的方法；通过删除这种本体子集，可以恢复本体的一致性。该方法将计算上述本体子集的问题归约为在命题逻辑程序中计算某种最优模型的问题，以调用现有的可满足性问题求解器来解决。 [非一致容忍推理方面] 本文将命题逻辑中字典序推理方法应用到描述逻辑中，以提供针对非一致本体的查询机制。本文还提出了一种在描述逻辑本体中进行字典序推理的方法。该方法将字典序结论的判定问题归约为命题可满足性判定问题，以调用现有的可满足性问题求解器来解决。

Solving MIN UR problem by triangle evolution algorithm with archiving and niche techniques

In this paper, as an extension of minimum unsatisfied linear relations problem (MIN ULR), the minimum unsatisfied relations (MIN UR) problem is investigated. A triangle evolution algorithm with archiving and niche techniques is proposed for MIN UR problem. Different with algorithms in literature, it solves MIN problem directly, rather than transforming it into many sub-problems. The proposed algorithm is also applicable for the special case of MIN UR, in which it involves some mandatory relations. Numerical results show that the algorithm is effective for MIN UR problem and it outperforms Sadegh's algorithm in sense of the resulted minimum inconsistency number, even though the test problems are linear.

Importance of self-consistency in relativistic continuum random-phase approximation calculations

A fully consistent relativistic continuum random phase approximation (RCRPA) is constructed, where the contribution of the continuum spectrum to nuclear excitations is treated exactly by the single-particle Green's function technique. The full consistency of the calculations is achieved that the same effective Lagrangian is adopted for the ground state and the excited states. The negative energy states in the Dirac sea are also included in the single-particle Green's function in the no-sea approximation. The currents from the vector meson and photon exchanges and the Coulomb interaction in RCRPA are treated exactly. The spin-orbit interaction is included naturally in the relativistic frame. Numerical results of the RCRPA are checked with the constrained relativistic mean-field theory. We study the effects of the inconsistency, particularly the currents and Coulomb interaction in various collective multipole excitations.

林地施肥与水肥效益

概述了国内外林地施肥的现状 ,简要论述了氮肥利用效率和水分利用效率在农林业生产中的意义。同时 ,阐述了水肥耦合的研究状况 ,并说明了水肥耦合理论应用于林业生产中以改善黄土高原因水肥不协调而形成大面积低效林的重要意义

水、氮、磷对杨树生物量的耦合效应

根据黄土高原因水肥不协调而形成大面积低效林的问题 ,以水肥耦合为中心 ,以 1龄杨树幼苗为研究对象 ,采用三因子五水平正交旋转组合回归设计方法 ,利用盆栽试验和定量分析的手段 ,研究探讨了不同水肥条件下 ,水、N、P三因子对杨树生物量的影响 ,结果表明三因素对杨树生物量存在着耦合交互效应 ,不同的水、N、P配合有不同的生物量积累 .因此 ,合理施肥、量水配肥是改善黄土高原因水肥不协调而形成大面积低效林的有效途径