1,025 research outputs found
Does innovation make a difference? An analysis of the performance of micro and small enterprises in the foodservice industry
Purpose – This paper aims to identify and measure the impact of the types of innovation on micro and small enterprises’ performance in the foodservice industry. Design/methodology/approach – A sample of 55 micro and small enterprises located in the Recife Metropolitan Area in Pernambuco were considered for the purpose of the analysis. All the firms were registered in the Agente Local de Inovação (ALI) program during the period of 2015 and 2016. The innovations developed by the firms were identified and measured using the sectorial innovation index, and the firm’s performance was calculated by the annual revenue. The impact of the innovations on performance was measured using multiple linear regression and quantile regression. Findings – The regressions’ findings suggest that two innovation dimensions stand out concerning firm performance, that is, brand and customer experience are thought as to contribute to firm performance significantly. However, it has also been found that the contribution of the innovations may vary in the level of firm performance. Originality/value – The paper was distinguished by analyzing the relationship between innovation and firm performance in the context of micro and small enterprises. The research also allowed knowing the innovations that can contribute to the micro and small enterprises’ performance, allowing such organizations to identify and develop the innovations seen as necessary for their competitiveness
Geophysical study of four possible impact structures localized in the Parnaíba basin and geological/geophysical detail of the Serra da Cangalha structure/TO
Orientadores: Alvaro Penteado Crósta, Eder Cassola MolinaAcompanhado de 2 mapas (folhas soltas dobradas), acondicionados em bolsoTese (doutorado) - Universidade Estadual de Campinas, Instituto de GeociênciasResumo: A Bacia sedimentar do Parnaíba abriga em seus domínios diversas estruturas circulares, das quais algumas têm sua origem atribuída a impactos meteoríticos sem que, no entanto, haja evidências comprobatórias. Esta tese aborda um estudo das assinaturas geofísicas das estruturas de São Miguel do Tapuio (SMT), Santa Marta (SM), Riachão (Ria) e Serra da Cangalha (SdC) utilizando dados aerogeofísicos de baixa resolução com o intuito de compará-las com outras crateras meteoríticas similares. Aborda também estudos geofísicos, utilizando dados aéreos de alta resolução e terrestres das estruturas de SdC e Ria, além de estudos geológicos de detalhe da estrutura de SdC, duas feições circulares com diâmetros de ~13 km (SdC) e ~4 km (Ria) localizadas nos estados de Tocantins e Maranhão, respectivamente. Os resultados fornecidos pelos métodos geofísicos mostram que a estrutura de SMT exibe alto magnético e assinatura gravimétrica variável, características estas não compatíveis com o padrão de estruturas de impacto similares; SM apresenta anomalia magnética negativa e gravimétrica positiva, características compatíveis com origem por impacto; Ria exibe altos magnético e gravimétrico na região central, e anomalia gamaespectrométrica circular com abundância de K, Th e U em sua porção central. Apesar da assinatura gravimétrica de Ria não ser claramente diagnóstica, a assinatura magnética é semelhante às de crateras de impacto similares. A estrutura de SdC apresenta anomalia gravimétrica da ordem de 1 mGal e dados aeromagnéticos mostram que o embasamento está a uma profundidade média de ~1,9 km, diminuindo para cerca de 500 a 1000 metros em sua porção central. Dados gamaespectrométricos revelam altos valores de K, Th e U no núcleo soerguido e alto Th e U na região externa próximo ao limite da cratera. Do ponto de vista morfo-estrutural SdC é constituída por núcleo soerguido que tem ~5,8 km de diâmetro e que possui em seu interior proeminente colar com ~3 km de diâmetro. Dados estruturais de campo, associados com análises de imagens de sensoriamento remoto, revelam WNW-ESE como a principal direção de deformação além de camadas invertidas preferencialmente concentradas no setor noroeste do colar, o que sugere um impacto oblíquo de sul para norte. Feições de deformação por choque incluem shatter cones, feather features (FF), planar fractures (PF) e planar deformation features (PDF) formadas ao longo da direção (0001), indicando pressão de choque <10 GPa. Esse conjunto de feições foi encontrado principalmente nas brechas polimíticas e shatter cones da depressão central e comprova a origem por impacto meteorítico da estrutura de SdC. Finalmente, resultados obtidos pela modelagem numérica da formação de SdC indicam que ela foi formada por um bólido com diâmetro de 1,4 km, viajando a 12 km/s, resultando na formação de uma cratera com ~15 km de diâmetro que liberou energia da ordem de 2,74x1020 J, considerando um nível atual de erosão de aproximadamente 500 metrosAbstract: The sedimentary Parnaíba basin encompasses in its domains several circular structures, some of which have their origin attributed to meteoritic impacts without, however, diagnostic evidence. This thesis presents a study of the geophysical signatures of the São Miguel do Tapuio (SMT), Santa Marta (SM), Riachão (Ria) and Serra da Cangalha (SdC) structures using low-resolution geophysical data, in order to compare them with other similar meteorite impact structures. It also employs high-resolution aerogeophysical and ground geophysical data for the SdC and Ria structures, and detailed geological data from SdC. These are two circular features ~13 km (SdC) and ~4 km (Ria) in diameter, and which are located in the state of Tocantins and Maranhão, respectively. The results provided by geophysical methods show that SMT exhibits a high gravity and variable magnetic signature, which are not compatible with the patterns of similar sized impact structures; SM has a negative magnetic anomaly and positive gravity anomaly, which is compatible with other impact structures; Ria exhibits high magnetic and gravity in the central region, and a circular gamma-ray anomaly with high levels of K, Th and U in the center. Despite the fact that the gravity signature of Ria is not clearly comparable with that of other impact craters, the magnetic signature is similar to that of other craters. SdC shows a gravity anomaly of ~1 mGal and there is magnetic evidence that the basement rocks sit at ~1.9 km depth, decreasing to about 500 to 1000 meters depth in the central region of the structure. Gamma-ray data show high values of K, Th and U over the central uplift and high Th and U in the region near the outermost limit of the crater. Morpho-structural analysis indicates that SdC contains a central uplift ~ 5.8 km in diameter with a prominent collar ~ 3 km wide in its inner zone. Structural data associated with remote sensing images show WNW-ESE as the main direction of deformation as well as overturned layers preferentially concentrated in the northwestern sector of the collar, which suggest an oblique impact from south to north. Shock deformation features include shatter cones, feather features (FF), planar fractures (PF), and planar deformation features (PDF) formed along (0001), indicating the shock pressure experienced by the rocks of the central uplift to have been <10 GPa. These features have been found in polymict breccias and shatter coned samples from the central depression and provide definite evidence that SdC was formed by meteorite impact. Finally, numerical modeling indicates that a meteorite some 1.4 km in diameter and impacting at a velocity of 12 km/s could have formed the originally ~15 km diameter crater, releasing energy of 2.74x1020 J, assuming a current erosion level of approximately 500 metersDoutoradoGeologia e Recursos NaturaisDoutor em Ciência
Data-driven classification of low-power communication signals by an unauthenticated user using a software-defined radio
Many large-scale distributed multi-agent systems exchange information over
low-power communication networks. In particular, agents intermittently
communicate state and control signals in robotic network applications, often
with limited power over an unlicensed spectrum, prone to eavesdropping and
denial-of-service attacks. In this paper, we argue that a widely popular
low-power communication protocol known as LoRa is vulnerable to
denial-of-service attacks by an unauthenticated attacker if it can successfully
identify a target signal's bandwidth and spreading factor. Leveraging a
structural pattern in the LoRa signal's instantaneous frequency representation,
we relate the problem of jointly inferring the two unknown parameters to a
classification problem, which can be efficiently implemented using neural
networks.Comment: Accepted for presentation at Asilomar Conference on Signals, Systems,
and Computers, 202
Interação e especulação em mercado interbancário de moedas
The paper aims to indicate how the contemporary micro-structure configuration
of foreign exchange markets induces their most important agents, i.e., the
marlEste artigo visa mostrar como a conformação microestrutural dos mercados
contemporâneos de câmbio induz os agentes que mais negociam nesses
mercados, isto é, os seus "market makers", a manterem intenso volume de
transações entre si e a assumirem comportamentos especulativos na busca
por informações. Isso, ao suscitar um caráter auto-referencial aos mercados
de divisas, termina "afrouxando" a relação entre taxa de câmbio e seus fundamentos
macroeconômicos. Surge, assim, a possibilidade de geração
endógena de movimentos das taxas de câmbio, ou seja, de flutuações cambiais
que não são explicadas por mudanças nos fundamentos, mas, sim, por
alterações de avaliações subjetivas e auto-realizáveis, algumas vezes otimistas,
outras pessimistas. Em conseqüência, há exacerbação dos movimentos
cambiais e redução do peso dos fundamentos para a determinação das taxas
de câmbio.
Palavras-chave
Taxa de câmbio; especulação; microestrutura do mercado cambial
Las consecuencias económicas del coronavirus
Esta nota presenta reflexiones sobre los posibles impactos que la pandemia de coronavirus tendrá en la economía. La interrupción de las cadenas de producción, la caída de la producción y los ingresos son impactos inmediatos. Sin embargo, también se espera que los efectos a largo plazo sean signifi cativos y negativos para
el crecimiento económico futuro
Optimality of Event-Based Policies for Decentralized Estimation over Shared Networks
Cyber-physical systems often consist of multiple non-collocated components that sense, exchange information and act as a team through a network.
Although this new paradigm provides convenience, flexibility and robustness to modern systems, design methods to achieve optimal performance are elusive as they must account for certain detrimental characteristics of the underlying network. These include constrained connectivity among agents, rate-limited communication links, physical noise at the antennas, packet drops and interference. We propose a new class of problems in optimal networked estimation where multiple sensors operating as a team communicate their measurements to a fusion center over an interference prone network modeled by a collision channel. Using a team decision theoretic approach, we characterize jointly optimal communication policies for one-shot problems under different performance criteria.
First we study the problem of estimating two independent continuous random variables observed by two different sensors communicating with a fusion center over a collision channel. For a minimum mean squared estimation error criterion, we show that there exist team-optimal strategies where each sensor uses a threshold policy. This result is independent of the distribution of the observations and, can be extended to vector observations and to any number of sensors. Consequently, the existence of team-optimal threshold policies is a result of practical significance, because it can be applied to a wide class of systems without requiring collision avoidance protocols.
Next we study the problem of estimating independent discrete random variables over a collision channel. Using two different criteria involving the probability of estimation error, we show the existence of team-optimal strategies where the sensors either transmit all but the most likely observation; transmit only the second most likely observation; or remain always silent. These results are also independent of the distributions and are valid for any number of sensors. In our analysis, the proof of the structural result involves the minimization of a concave functional, which is an evidence of the inherent complexity of team decision problems with nonclassical information structure.
In the last part of the dissertation, the assumption on the cooperation among sensors is relaxed, and we show that similar structural results can also be obtained for systems with one or more selfish sensors. Finally the assumption of the independence is lifted by introducing the observation of a common random variable in addition to the private observations of each sensor. The structural result obtained provides valuable insights on the characterization of team-optimal policies for a general correlation structure between the observed random variables
EM BUSCA DO CRESCIMENTO PERDIDO: EXPLICAÇÕES PARA A PERSISTÊNCIA DA CRISE ECONÔMICA DE 2007/2008 NOS PAÍSES DESENVOLVIDOS
O presente artigo apresenta e examina algumas explicações para a dificuldade de recuperação dos países desenvolvidos no pós-crise econômica de 2007/08. Essa foi tão severa para as economias desenvolvidas que passou a receber o epiteto de a “Grande Crise”. Embora não tenha apresentada a mesma magnitude de queda nos níveis de atividade econômica e no emprego que a Grande Depressão de 1929, a duração dos efeitos da Grande Crise tem chamado à atenção de diversos economistas. Aqui se expõe três das principais hipóteses explicativas para tal fenômeno: a de estagnação secular; a de headwinds; e a de efeito histerese. Mesmo partindo de diferentes premissas, elas compartilham uma visão pessimista sobre a trajetória futura das taxas de crescimento econômico para as próximas décadas. Da mesma forma, apontam implicações e novos desafios para a condução da política econômica e para a própria teoria econômic
MERCADO CAMBIAL CONTEMPORÂNEO
Este artigo busca sintetizar algumas das principais características e
transformações estruturais do mercado internacional de câmbio na
última década. O intuito é apontar como os fatores, que fizeram o
volume de recursos a circular diariamente neste mercado crescer a
taxas elevadas nos últimos dez anos, podem ter também
responsabilidade pelos períodos de volatilidade e desalinhamento
cambial e pela emergência mais freqüente de casos de crises cambiais
na década de noventa.
Abstract
This paper synthesizes some of the main characteristics and structural
changes that took place in the international exchange market in
the last decade. Its aim is to show how the same causes that made the
international amount of resources circulating daily in that market increase
significantly in the last ten years, may have also some responsibility
for the periods of exchange volatility and disarray, and for the
increased frequency of exchange crises in the 1990s
Maximal Dissent: a State-Dependent Way to Agree in Distributed Convex Optimization
Consider a set of agents collaboratively solving a distributed convex
optimization problem, asynchronously, under stringent communication
constraints. In such situations, when an agent is activated and is allowed to
communicate with only one of its neighbors, we would like to pick the one
holding the most informative local estimate. We propose new algorithms where
the agents with maximal dissent average their estimates, leading to an
information mixing mechanism that often displays faster convergence to an
optimal solution compared to randomized gossip. The core idea is that when two
neighboring agents whose distance between local estimates is the largest among
all neighboring agents in the network average their states, it leads to the
largest possible immediate reduction of the quadratic Lyapunov function used to
establish convergence to the set of optimal solutions. As a broader
contribution, we prove the convergence of max-dissent subgradient methods using
a unified framework that can be used for other state-dependent distributed
optimization algorithms. Our proof technique bypasses the need of establishing
the information flow between any two agents within a time interval of uniform
length by intelligently studying convergence properties of the Lyapunov
function used in our analysis
Liberalização e desregulamentação bancária: motivações, consequências e adaptações [Liberalization and deregulation in the banking industry: motivations, outcomes, and adaptations]
Over the last two decades, almost all countries in the world have experienced a noticeable process of liberalization and deregulation. This process has both motivated and propelled changes in the very competitive dynamics of the banking industry. Therefore, various OECD countries have changed their regulatory/prudential practices concerning the banking market, in order to make them more suitable to the new competitive environment. Conversely, liberalization and deregulation in developing countries have often been started and deepened without any prior effort to strengthen and/or change the banking regulatory arrangements. The aim of this paper is to outline some features of such a process, by underlining some of the observed outcomes in the countries where it has gone further as well as the necessary adaptations for the banking regulation policy.banking industry, restructuring, regulation
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