Experimental Study on Channel Reciprocity in Wireless Key Generation

Key generation from wireless channels is a promising alternative to public key cryptography for the establishment of cryptographic keys. It is the first paper to experimentally study the channel reciprocity principle of key generation, through investigating and quantifying channel measurements' cross-correlation relationship affected by noise and non-simultaneous measurements. Channel measurements, both received signal strength and channel state information, are collected from a real experimental platform using the wireless open access research platform (WARP) in a multipath office room. We found that in a slow fading channel (e.g., with a coherence time of about 50~ms), the channel cross-correlation is impacted greatly by noise but little by non-simultaneous measurements with a small sampling time difference (e.g., 0.06 ms). The resolution of the sampling time difference can be satisfied by wireless systems such as IEEE 802.11 to maintain an acceptable cross-correlation coefficient without affecting the bandwidth and communication efficiency.

Land grabbing, investors, and indigenous peoples: new legal strategies for an old practice?

This article examines how new legal strategies need to be adopted by indigenous peoples to react to the increasing phenomenon of ‘land grabbing’ taking place across the globe. In examining the specificity of the ‘land grab’ and how it particularly affects indigenous peoples, it analyses how new legal strategies targeting the investors need to be adopted by communities to mitigate some of the negative aspects of land grabbing. It argues that since the current ‘land grab’ is driven by investors it is important that indigenous peoples, and their supportive organisations, target investors and lending institutions which are behind the massive investments in land acquisitions.

Circulation patterns and processes in Barkley Sound, Vancouver, BC

Senior thesis written for Oceanography 444

The role, organisation and contribution of community enterprise to urban regeneration policy in the UK

This monograph investigates the organisation, constitution and delivery of community-based organisations which are normally called community enterprises in the UK. These are organisations which emerge from local communities at the neighbourhood level, work in partnership with the public and private sectors, and provide a range of services to meet social, economic and environmental needs. The main focus of the paper is to explore how these organisations contribute to local regeneration strategies, generate social capital and contribute towards the promotion of civil society in general. The main emphasis is on organisations in England and Wales but comparisons are made with the USA and other countries where relevant literature is available. The key questions to be answered relate to the organisation and management of these bodies; the extent to which they engage with and contribute to local regeneration strategies; and the impact they have particularly in acquiring and managing assets. The diversity of the sector, and the range, scale and level of benefits it can deliver is illustrated through five detailed case studies of community enterprises established at different times, in different geographical locations and with different objectives and funding regimes. But, whilst the UK political economy is moving towards less state intervention and more community self-help, the community development corporations in the USA provide an indication of the future direction community enterprises might take in the UK as part of a broad trend towards civic capacity building.

The significance of Marx's value for strategy theory: competitive advantage and the issue of tautology within the resource-based view of the firm

Marxian thinking following the TSSI (Temporal Single System Interpretation) of Marx is applied to refute the allegation of a tautology in the resource-based view of the firm--paired with providing an explanation of how and why resources create value--, where resources are synonymous with Marx's categories of constant and variable capital. Refuting the allegation naturally leads to the holy grail of resource-based thinking, i.e. the question of what, conceptually, constitutes a firm's competitive advantage within the industry context. The article achieves its objectives by tying the resource-based view into Marx's theory value.

Improving health and wellbeing independently of GDP: dividends of greener and prosoical economies

Increases in gross domestic product (GDP) beyond a threshold of basic needs do not lead to further increases in well-being. An explanation is that material consumption (MC) also results in negative health externalities. We assess how these externalities influence six factors critical for well-being: (i) healthy food; (ii) active body; (iii) healthy mind; (iv) community links; (v) contact with nature; and (vi) attachment to possessions. If environmentally sustainable consumption (ESC) were increasingly substituted for MC, thus improving well-being and stocks of natural and social capital, and sustainable behaviours involving non-material consumption (SBs-NMC) became more prevalent, then well-being would increase regardless of levels of GDP. In the UK, the individualised annual health costs of negative consumption externalities (NCEs) currently amount to £62 billion for the National Health Service, and £184 billion for the economy (for mental ill-health, dementia, obesity, physical inactivity, diabetes, loneliness and cardiovascular disease). A dividend is available if substitution by ESC and SBs-NMC could limit the prevalence of these conditions.

Gentrifying the Peri-urban: Land use Conflicts and institutional dynamics at the Frontier of an Indonesian Metropolis

This paper aims to specify the meaning of gentrification in rapidly peri-urbanising metropolitan regions in the context of Indonesia’s rapid transition to decentralisation and democracy. It discusses a case study of conflict over an environmental revitalisation project in a peri-urban area of Bandung City. The analysis focuses on the political processes, tactics and strategies supporting and opposing peri-urban gentrification and their consequences. The analysis illustrates how these political dynamics mediate the interaction between the movement of capital and the spatial reorganisation of social classes. It is argued that in the context of a peri-urbanising metropolis, gentrification needs to be narrated less in terms of class-based neighbourhood succession and more in terms of competing cross-class coalitions emerging at local and regional levels.

A Migrant Culture on Display: The French Migrant and French Gastronomy in London (19th – 21st centuries)

The large contemporary French migrant population – estimated by the French Consulate at around 300,000–400,000 in the UK, the majority living in London and the South-East – remains ‘absent’ from studies on migration, and, in a study of migrant food history in Britain, is considered not to have left traces as a migrant community. Over the centuries, the presence of various French communities in London has varied significantly as far as numbers are concerned, but what does not change is their simultaneous ‘visibility’ and ‘invisibility’ in accounts of the history of the capital: even when relatively ‘visible’ at certain historical moments, they still often remain hidden in its histories. At times the French in London are described as a ‘sober, well-behaved […] and law-abiding community’; at other times they ‘appeared as a foreign body in the city’. This article reflects on the dynamics at play between a migrant culture associated with high cultural capital (so much so that is often emulated by those who are not French) and the host culture perception of and relationship to it, in order to consider what this may ‘mean’ for the French (and Francophone) migrant experience. French gastronomy and culinary knowledge is taken as an example of material culture and of cultural capital ‘on display’ specifically in the activity of dining out, especially in French restaurants, or in those influenced by French gastronomy. The social activity of dining out is replete with displays of knowledge (linguistic, culinary), of cultural literacy, of modes of behaviour, of public identity, and of rituals strictly codified in both migrant and host cultures. Dining out is also an emotional and politically-charged activity, fraught with feelings of suspicion (what is in the food? what does the chef get up to in the kitchen?) and of anxieties and tensions concerning status, class and gender distinctions. This article considers the ways in which the migrant French citizen of London may be considered as occupying an ambiguous position at different times in history, simultaneously possessing cultural capital and needing to negotiate complex cultural encounters in the connections between identity and the symbolic status of food in food production, food purveying and food consumption.

A hierarquia dos determinantes da estrutura de capital em empresas portuguesas

Dissertação de Mestrado apresentado ao Instituto de Contabilidade e Administração do Porto para a obtenção do grau de Mestre em Contabilidade e Finanças, sob orientação de Adalmiro Álvaro Malheiro de Castro Andrade Pereira

O capital intelectual e a performance das empresas do PSI 20

Num contexto de crescente complexidade e disponibilidade de informação, a gestão do capital intelectual assume cada vez mais preponderância como vantagem competitiva para as empresas que procuram maximizar o valor gerado. Esta investigação usa como metodologia príncipal o VAIC (coeficiente intelectual do valor adicionado), para assim estudar a existência de relação entre capital intelectual e a performance bolsista e financeira das empresas do PSI20. O VAIC é decomposto nos seus três indicadores de eficiência, tais como: capital humano, capital estrutural e capital físico. Os dados contemplam quinze empresas e nove anos de análise (2003 - 2011). Elaborou-se uma abordagem que recorre à utilização de técnicas econométricas para reduzir potênciais falhas no tratamento de dados em painel. Os resultados da análise demonstram uma relação positiva entre a aposta em capital intelectual a performance bolsista e financeira, ou seja, a utilização e gestão eficientes do capital intelectual contribuem de forma significativa na avaliação bolsista e financeira das empresas do PSI20.

O impacto do capital intelectual na performance

Para as organizações sobreviverem num novo ambiente competitivo, tiveram que deixar de procurar obter vantagens competitivas nos seus recursos tangíveis para as procurarem nos ativos intangíveis. Assim, várias investigações comprovam a necessidade de se dar a devida importância ao conceito de Capital Intelectual como fonte de criação de vantagens competitivas para as organizações. Esta importância aplica-se a vários níveis de análise entre os quais o setor público. Esta investigação visa analisar a importância relativa de cada dimensão do capital intelectual de uma Instituição de Ensino, bem como o impacto do mesmo na performance (percecionada pelos seus stakeholders). Nesta dissertação adotamos o método de Estudo de Caso, utilizando uma abordagem mista – quantitativa e qualitativa. Utilizámos variadas técnicas na recolha de dados, tais como: entrevista, registo de áudio e questionários. Relativamente à análise de dados, efetuamos uma análise de conteúdo, análise de documentos e análise estatística. Ao nível de resultados, a análise qualitativa sugere que as três dimensões do Capital Intelectual (Capital Humano, Capital Estrutural e Capital Relacional) devem possuir a mesma importância relativa para avaliar o capital intelectual de uma Instituição de Ensino. Os resultados quantitativos sugerem que o capital intelectual tem impacto na performance, o que está em linha com a literatura sobre o tema. Finalmente, considerámos que esta tese contribui para uma sensibilização relativamente à importância do capital intelectual para melhorar a gestão e performance em contextos educacionais.

A importância do capital humano nas organizações

Os ativos intangíveis são cada vez mais uma preocupação das organizações, e atualmente são reconhecidos como os principais ativos das empresas. O Capital Humano como dimensão do Capital Intelectual é um fator preponderante no desenvolvimento e crescimento das organizações, uma vez que proporciona criação de valor e vantagem competitiva para as empresas. A criação, a partilha e a transferência de Conhecimento são, também, fatores influentes que geram Capital Humano. Na atualidade, este tema tem despertado o interesse tanto de economistas, gestores e contabilistas, como de meros investidores. O Capital Intelectual é tradicionalmente concetualizado como sendo composto por três grandes dimensões: Capital Humano, Capital Relacional e Capital Estrutural. Por sua vez, daquilo que é o nosso conhecimento, consideramos que existe uma lacuna na literatura sobre Capital Humano no que diz respeito à sua taxonomia. Efetivamente grande parte das investigações sobre Capital Humano, como dimensão do Capital Intelectual, focam-se essencialmente nos itens necessários para a sua mensuração do CH. Desta forma, o objetivo principal deste estudo consiste em explorar a dimensão do CH ao nível das suas componentes. Ou seja, procuramos encontrar as componentes do Capital Humano e propomo-nos a determinar quais as que têm maior importância no CH para o desenvolvimento e crescimento das organizações. Para esta realização efetuámos um estudo de carácter exploratório, num contexto específico do mercado português – o Setor Segurador. Os resultados obtidos tanto a nível qualitativo como quantitativo vão de encontro às questões de investigação previamente definidas. Portanto, as componentes mais importantes do CH são: a formação e o bem-estar, o conhecimento e o profissionalismo e as características pessoais e técnicas dos colaboradores que constituem os Recursos Humanos da organização. Estas são aquelas que mais valorizam e proporcionam crescimento nas organizações. Este estudo poderia ser tão mais completo, se pudéssemos apresentar uma comparação entre duas empresas seguradoras e, consequentemente analisar o comportamento das duas face ao Capital Humano. Outro aspeto interessante seria efetuar uma análise sobre qual o impacto do Capital Humano na performance financeira das organizações seguradoras. Estas são limitações que podem ser vistas como sugestões para estudos de investigação futuros nesta mesma área. Este estudo contribui para o enriquecimento das investigações na área do Capital Humano, uma vez que conhecendo melhor as componentes que constituem o CH mais facilmente as organizações definem as suas estratégicas de crescimento e desenvolvimento. Desta forma, este estudo pode apoiar alguns gestores na definição de políticas de valorização deste ativo intangível em organizações do mercado segurador.

Scalable and interference aware wi-fi mesh networks using cots devices

A crescente tendencia no acesso móvel tem sido potenciada pela tecnologia IEEE 802.11. Contudo, estas redes têm alcance rádio limitado. Para a extensão da sua cobertura é possível recorrer a redes emalhadas sem fios baseadas na tecnologia IEEE 802.11, com vantagem do ponto de vista do custo e da flexibilidade de instalação, face a soluções cabladas. Redes emalhadas sem fios constituídas por nós com apenas uma interface têm escalabilidade reduzida. A principal razão dessa limitação deve-se ao uso do mecanismo de acesso ao meio partilhado Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) em topologias multi-hop. Especificamente, o CSMA/CA não evita o problema do nó escondido levando ao aumento do número de colisões e correspondente degradação de desempenho com impacto direto no throughput e na latência. Com a redução da tecnologia rádio torna-se viável a utilização de múltiplos rádios por nó, sem com isso aumentar significativamente o custo da solução final de comunicações. A utilização de mais do que um rádio por nó de comuniações permite superar os problemas de desempenho inerentes ás redes formadas por nós com apenas um rádio. O objetivo desta tese, passa por desenvolver uma nova solução para redes emalhadas multi-cana, duar-radio, utilizando para isso novos mecanismos que complementam os mecanismos definidos no IEEE 802.11 para o estabelecimento de um Basic Service Set (BSS). A solução é baseada na solução WiFIX, um protocolo de routing para redes emalhadas de interface única e reutiliza os mecanismos já implementados nas redes IEEE 802.11 para difundir métricas que permitam à rede escalar de forma eficaz minimizando o impacto na performance. A rede multi-hop é formada por nós equipados com duas interfaces, organizados numa topologia hierárquica sobre múltiplas relações Access Point (AP) – Station (STA). Os resultados experimentais obtidos mostram a eficácia e o bom desempenho da solução proposta face à solução WiFIX original.

Relationship between national culture, democracy and environmental performance: A panel data analysis

This paper demonstrates the significance of culture in examining the relationshipbetween democratic capital and environmental performance.The aim is to examine the relationship among scores on the Environmental Performance Index and the two dimensions of cross cultural variation suggested by Ronald Inglehart and Christian Welzel. Significantional interrelationships among democracy, cultural and environmental sustaintability measures could be found, following the regression results. Firstly, higher levels of democratic capital stock are associated with better environmental performance. Secondly importance to distinguish between cultural groups could be confirmed.

Differential regulations of AQP4 and Kir4.1 by triamcinolone acetonide and dexamethasone in the healthy and inflamed retina.

PURPOSE: Glucocorticoids are used to treat macular edema, although the mechanisms underlying this effect remain largely unknown. The authors have evaluated in the normal and endotoxin-induced uveitis (EIU) rats, the effects of dexamethasone (dex) and triamcinolone acetonide (TA) on potassium channel Kir4.1 and aquaporin-4 (AQP4), the two main retinal Müller glial (RMG) channels controlling retinal fluid movement. METHODS: Clinical as well as relatively low doses of dex and TA were injected in the vitreous of normal rats to evaluate their influence on Kir4.1 and AQP4 expression 24 hours later. The dose-dependent effects of the two glucocorticoids were investigated using rat neuroretinal organotypic cultures. EIU was induced by footpad lipopolysaccharide injection, without or with 100 nM intraocular dex or TA. Glucocorticoid receptor and channel expression levels were measured by quantitative PCR, Western blot, and immunohistochemistry. RESULTS: The authors found that dex and TA exert distinct and specific channel regulations at 24 hours after intravitreous injection. Dex selectively upregulated Kir4.1 (not AQP4) in healthy and inflamed retinas, whereas TA induced AQP4 (not Kir4.1) downregulation in normal retina and upregulation in EIU. The lower concentration (100 nM) efficiently regulated the channels. Moreover, in EIU, an inflammatory condition, the glucocorticoid receptor was downregulated in the retina, which was prevented by intravitreous injections of the low concentration of dex or TA. CONCLUSIONS: The results show that dex and TA are far from being equivalent to modulate RMG channels. Furthermore, the authors suggest that low doses of glucocorticoids may have antiedematous effects on the retina with reduced toxicity.