Efficient Management of Insecure Fossil Fuel Imports through Taxing (!) Domestic Green Energy?

A small open economy produces a consumer good, green and black energy, and imports fossil fuel at an uncertain price. Unregulated competitive markets are shown to be inefficient. The implied market failures are due to the agents’ attitudes toward risk, to risk shifting and the uniform price for both types of energy. Under the plausible assumptions that consumers are prudent and at least as risk averse as the producers of black energy, the risk can be efficiently managed by taxing emissions and green energy. The need to tax (!) green energy contradicts the widespread view that subsidization of green energy is an appropriate means to enhance energy security in countries depending on risky fossil fuel imports.price uncertainty, black energy, green energy, fossil fuel

Process algebraic frameworks for the specification and analysis of cryptographic protocols

Two process algebraic approaches for the analysis of cryptographic protocols, namely the spi calculus by Abadi and Gordon and CryptoSPA by Focardi, Gorrieri and Martinelli, are surveyed and compared. We show that the two process algebras have comparable expressive power, by providing an encoding of the former into the latter. We also discuss the relationships among some security properties, i.e., authenticity and secrecy, that have different definitions in the two approaches

A synthesis of rural livelihood approaches in analysing household poverty, food security and resilience: A case study of Rushinga rural district in Zimbabwe.

Doctor of Philosophy in Food Security. University of KwaZulu-Natal, Pietermaritzburg 2018.Understanding rural livelihoods is an important goal to achieve the Sustainable Development Goals in Zimbabwe, in particular eradicating poverty and food insecurity in every household. Even though livelihoods of the rural poor are susceptible to recurrent shocks, risks and stresses, fostering resilience on rural livelihood approaches is a significant remedy for achieving household well-being. However rural livelihood failure to mitigate widespread poverty and food insecurity have never been adequately examined or explained in a context that can encourage rural development policies. The study provides a comprehensive analysis of livelihood approaches, specifically endeavouring to answer the following questions: What livelihood factors determine rural poverty and its dimensions in the study area? What is the extent of household vulnerability to food insecurity? Is the degree of livelihood resilience and adaptation to attain food security sustainable? The main objective of the study was to use the concept of livelihoods as the springboard to analyse and measure household vulnerability to poverty and food insecurity as well as the level of rural resilience. The study focused on three distinct Wards in the Rushinga District, Zimbabwe. The multi-stage sampling procedure was adopted to select fifteen villages and simple random sampling was used to select 300 households for the survey, 100 from each Ward and 20 from each village. The household level was used as the appropriate unit of analysis, because on aggregate, pooling of labour, consumption, resources, coping and survival strategies are relatively identified from a household perspective, as a common unit of analysis. Data analysis employed econometric models to compare livelihood outcomes from different socio-economic variables included in the study. Descriptive statistics such as chi-square, t-test, mean, percentages and frequencies were used to answer the objectives of the study and test the hypothesis. A theory of rural livelihood approaches was developed using conceptual frameworks compatible to the context of the study; the Sustainable Livelihood Framework (SLF), micro-level food security framework and the Resilience Framework (RF). In other words, the frameworks strive to explain that positive household well-being is a result of successful livelihood approaches and negative well-being is the result of livelihood failure. The Sustainable Livelihood Framework is an appropriate checklist tool to understand how poverty is influenced by socio-environmental factors, and also important for eradication models. It describes the relationship between the environmental context and the capitals or assets available to the rural poor. In negotiating possible livelihood outcomes, the poor select from a range of available options within a particular context and locality, and the study shows that natural and social capital are easily available to the poor. The Food Security Conceptual Framework (FSCF), just like the SLA, identifies the reason some households become food secure and some food insecure. It is because livelihood activities, processes and outcomes differ from one household to the other. Household food security is a function of availability and access to adequate food, both dimensions hinge on resource endowments to acquire sufficient food. Furthermore, the stability of availability and access to food is considered an important dimension of food security as well as utilisation which has a bearing on nutritional security. Utilisation is considered a biological perspective of food security; as the ability of the human body to ingest and metabolise food. Because of the vulnerability context within livelihood approaches, which eventually result in poverty traps, the study shows that the poor find themselves food insecure. When compared to resourceful households who are food secure, they have the capacity to produce and procure adequate food. In other words, food insecurity in the District was a result of poverty, as the poor lack the means to pursue other livelihood options. The Resilience Framework improves the understanding of how the interaction of capacity, socio-economic and environmental factors affect rural livelihoods and household consumption welfare. The study revealed that highly exposed and sensitive livelihood systems eventually “collapse”, leading to vulnerability to food insecurity as compared other household’s livelihood systems which were highly adaptive, resulting in easy “bouncing back” to normal household’s functions. Thus, livelihood approaches, in complex rural context, can only be sustainable to warrant food security if strengthened by the resilience of socio-ecological structures. Quantitative estimation of the dimensions of poverty measured in monetary metrics and food insecurity measured in calorie intake per adult equivalence using the Foster, Greer and Thorbecke (FGT) indices revealed that 70% of households were poor, thus, living below absolute food poverty line, average poverty gap was 38% and severity 15%. The prevalence calls for relevant stakeholders like the government to scale up efforts to minimize household poverty. Since poverty in this study was measured in terms of expenditure on food, household’s lack of purchasing power means households could be food insecure. Generally, the prevalence of food insecurity was high in the District; 60% households were deemed food insecure, the depth of food shortage per adult equivalence was 24% and the inequality among the food insecure households themselves was 13%. Notably, the results indicated that poverty and food insecurity were gender skewed and geographically concentrated. There were more poor female headed-households than male-headed households, and concentration of household vulnerability to food poverty in Ward 12 signals geographical poverty. This all points to inequality when it comes to controlling and access to key productive resources to enhance their livelihoods. At the household level, food insecurity alleviation strategies and policies should aim to empower women and transform the livelihood choices and priorities of vulnerable groups in society. The study revealed a strong relationship between geographically defined factors and level of well-being. Spatial disparities in living standards were caused by the existence of geographical poverty traps which caused cycles of livelihood failure, for example, inequality in resource endowments, education and health services and a host of other social economic factors. To examine the determinants of poverty, the study utilized a binary logic model. The results of the econometric model revealed that rural poverty is linked to geographic location, dependency ratio, marital status, total monthly income per capita, asset endowment, access to support services and maize yield (statistically significant at 10% and below). The implication of this result is that not a single livelihood predicator can cause poverty. These variables interact at a scale beyond the control of households, causing households to fall into severe poverty, over a given point in time. A binary logit model was also used to estimate the determinants of household food security, daily calorie availability per adult equivalence was adopted as the dependent variable. The results showed that household food insecurity was linked to dependency ratio, per capita monthly income, the value of assets, total livestock units (TLU) and maize yield. In the rural context, there was a link between the predictors of poverty and food insecurity. Whenever poor households were confronted with either transitory or chronic food insecurity, they developed mild, moderate and more severe food deficit coping strategies. Generally, the households in the study used minimal coping strategies, the cause was attributed to the availability of external aid rationings which eased the severity. Even though the utility of natural resources, in particular, land-based activities, constituted an important source of livelihoods, as Zimbabwe is regarded an agricultural economy, the sector has become a poverty and food insecurity trap. At the same time, results exhibited rural livelihood transition from conventional activities. In the rural context, the transition is owed to uncertainty in agriculture, because of erratic rainfall, shortage of labour, high costs of inputs, land degradation, among other factors. Resilience is a developing research discipline in the wake of climate change, described in different ways and understood in complex dimensions depending on context. In the context of rural livelihoods, it is described as the capacity of the rural economy to simultaneously balance social, economic, ecosystem and cultural functions when confronted with predicted or unpredicted vulnerability. As such, rural livelihood resilience is the ability of the socio-ecological system to cope, adapt absorb and transform from change. This study strives to quantitatively measure resilience in the domain of food security. Food security is an important aspect that every household strives to achieve. High costs of farm inputs, market failure, and rising food costs were among notable shocks uncounted by households in the study. However, agricultural drought was the major livelihood threat to land-based activities, as nearly 94% of interviewed households who relied on own production for their food security recorded absolute crop failure. To measure household resilience against food insecurity, the study used two-stage factor analysis using the Principal Component Factor method. The model considers resilience against food insecurity as available household options over a given time. Among other options, adaptive capacity is the most important livelihood option, which is the ability of a system to adjust and take advantage of opportunities in order to offset risks and shocks. Access to natural resources was not significant enough to explain resilience against food insecurity, this is mainly attributed to degradation of the resources or inequitable access, for example to land. Validation of the mean resilience index indicates that livelihood diversification correlates with high resilience because of high adaptive capacity as compared to a single livelihood option. The mean resilience index also revealed that male-headed households improved adaptive capacity, given their better access to resources, whereas female-headed remained vulnerable because they were either involved in non-diversified livelihoods or they are constrained in accessing productive assets and low endowment in human capital. Thus, rural development policies should spur livelihood diversification as core resilience strategy against food shortages

Formal Models and Techniques for Analyzing Security Protocols: A Tutorial

International audienceSecurity protocols are distributed programs that aim at securing communications by the means of cryptography. They are for instance used to secure electronic payments, home banking and more recently electronic elections. Given The financial and societal impact in case of failure, and the long history of design flaws in such protocol, formal verification is a necessity. A major difference from other safety critical systems is that the properties of security protocols must hold in the presence of an arbitrary adversary. The aim of this paper is to provide a tutorial to some modern approaches for formally modeling protocols, their goals and automatically verifying them

A Reduced Semantics for Deciding Trace Equivalence

Many privacy-type properties of security protocols can be modelled using trace equivalence properties in suitable process algebras. It has been shown that such properties can be decided for interesting classes of finite processes (i.e., without replication) by means of symbolic execution and constraint solving. However, this does not suffice to obtain practical tools. Current prototypes suffer from a classical combinatorial explosion problem caused by the exploration of many interleavings in the behaviour of processes. M\"odersheim et al. have tackled this problem for reachability properties using partial order reduction techniques. We revisit their work, generalize it and adapt it for equivalence checking. We obtain an optimisation in the form of a reduced symbolic semantics that eliminates redundant interleavings on the fly. The obtained partial order reduction technique has been integrated in a tool called APTE. We conducted complete benchmarks showing dramatic improvements.Comment: Accepted for publication in LMC

Process algebraic frameworks for the specification and ana lysis of cryptographic protocols

Two process algebraic approaches for the analysis of cryptographic protocols, namely the spi calculus by Abadi and Gordon and CryptoSPA by Focardi, Gorrieri and Martinelli, are surveyed and compared. We show that the two process algebras have comparable expressive power, by providing an encoding of the former into the latter. We also discuss the relationships among some security properties, i.e., authenticity and secrecy, that have different definitions in the two approaches

A systematic review of local vulnerability to climate change: in search of transparency, coherence and comparability

Because vulnerability is a conceptual construct rather than a directly observable phenomenon, most vulnerability assessments measure a set of “vulnerability indicators”. In order to identify the core approaches and range of variation in the field, we conducted a systematic literature review on local vulnerability to climate change. The systematic review entailed an identification of frameworks, concepts, and operationalizations and a transparency assessment of their reporting. Three fully defined relevant frameworks of vulnerability were identified: IPCC, Patterns of Smallholder Vulnerability and Vulnerability as Expected Poverty. Comparative analysis found substantial heterogeneity in frameworks, concepts and operationalizations, making it impossible to identify patterns of climate vulnerability indicators and determinants that have robust empirical support. If research measuring farmers’ vulnerability to climate change is to have any comparability, it needs greater conceptual coherence and empirical validity. We recommend a systematic program of testing and validating vulnerability measures before institutionalizing them in programmatic contexts