169,973 research outputs found
Numerical Power Analysis
No full textIn this paper we design abstract domains for numerical power analysis. These domains are conceived to discover properties of the following type: `The integer (or rational) variable X at a given program point is the numerical power of c with the exponent having a given property P'', where c and P are automatically determined. A family of domains is presented, two of these consider that the exponent can be any natural or integer value, the others include also the analysis of properties of the exponent set. Relevant lattice-theoretic properties of these domains are proved such as the absence of infinite ascending chains and the structure of their meet-irreducible elements. These domains are applied in the analysis of integer powers of imperative programs and in the analysis of probabilistic concurrent programming, with probabilistic non-deterministic choice
Algebraic Power Analysis by Abstract Interpretation
No full textIn this paper we design abstract domains for power analysis. These domains are conceived to discover properties of the following type: ``The variable X at a given program point is the power of c with the exponent having a given property p'', where c and p are automatically determined. This construction is general and include different algebraic entities, such as numerical and polynomial (with rational coefficients), as bases. Several families of domains are presented, some of these consider that the exponent can be any natural or integer value, the others include also the analysis of properties of the exponent set. Relevant lattice-theoretic properties of these domains are proved such as the absence of infinite ascending chains and the structure of their meet-irreducible elements. The numerical domains are applied in the analysis of integer powers of imperative programs and in the analysis of probabilistic concurrent programming, with probabilistic non-deterministic choice. Moreover we use the numerical power domains in order to analyze the factorization of integer variables, i.e., invariant properties of factors and of their exponents. In this way we are able to statically detect information hidden in prime factorization, which is useful in software watermarking
Insurance Pricing and Refund Sustainability for Cloud Outages.
No full textCloud outages may cause heavy economic losses for customers, who may ask the cloud provider for compensation. Cloud providers may therefore wish to insure themselves against that risk. Considering a scenario where outages take place according to a Poisson process and their duration follows a generalized Pareto model, we provide formulas to properly set the insurance premium under three measures of outage severity: number of outages, number of long outages, unavailability. We also assess the sustainability of refunds, by setting thresholds on unit refund per damaging events
Proper or Weak Efficiency via Saddle Point Conditions in Cone-Constrained Nonconvex Vector Optimization Problems
No full textMotivated by many applications (for instance, some production models in finance require infinity-dimensional commodity spaces, and the preference is defined in terms of an ordering cone having possibly empty interior), this paper deals with a unified model, which involves preference relations that are not necessarily transitive or reflexive. Our study is carried out by means of saddle point conditions for the generalized Lagrangian associated with a cone-constrained nonconvex vector optimization problem. We establish a necessary and sufficient condition for the existence of a saddle point in case the multiplier vector related to the objective function belongs to the quasi-interior of the polar of the ordering set. Moreover, exploiting suitable Slater-type constraints qualifications involving the notion of quasi-relative interior, we obtain several results concerning the existence of a saddle point, which serve to get efficiency, weak efficiency and proper efficiency. Such results generalize, to the nonconvex vector case, existing conditions in the literature. As a by-product, we propose a notion of properly efficient solution for a vector optimization problem with explicit constraints. Applications to optimality conditions for vector optimization problems are provided with particular attention to bicriteria problems, where optimality conditions for efficiency, proper efficiency and weak efficiency are stated, both in a geometric form and by means of the level sets of the objective functions
The impact of Clean Spark Spread expectations on storage hydropower generation
No full textStorage hydropower generation plays a crucial role in the electric power system and energy transition because it is the most widespread power generation with low greenhouse gas emissions and, moreover, it is relatively cheap to ramp up and down. As a result, it provides flexibility to the grid and helps mitigate the short-term production uncertainty that affects most green energy technologies. However, using water in reservoirs represents an opportunity cost, which is related to the evolution of plant production capacity and production profitability. As the latter is related to a wide range of types of variables, in order to incorporate it in a large-scale prediction model it is important to select the variables that impact most on storage hydropower generation. In this paper, we investigate the impact of the variables influencing the choices of price maker producers, and, in particular we study the impact of Clean Spark Spread expectations on storage hydroelectric generation. In this connection, using entropy and machine learning tools, we present a method for embedding this expectations in a model to predict storage hydropower generation, showing that, for some time horizon, expectations on CSS have a greater impact than expectations on power prices. It is shown that, if the right mix of power price and CSS expectations is considered, the prediction error of the model is drastically reduced. This implies that it is important to incorporate CSS expectations into the storage hydropower model
An Inexact Proximal-Type Method for the Generalized Variational Inequality in Banach Spaces
No full text We investigate an inexact proximal-type method, applied to the generalized variational inequality problem with maximal monotone operator in reflexive Banach spaces. Solodov and Svaiter (2000) first introduced a new proximal-type method for generating a strongly convergent sequence to the zero of maximal monotone operator in Hilbert spaces, and subsequently Kamimura and Takahashi (2003) extended Solodov and Svaiter algorithm and strong convergence result to the setting of uniformly convex and uniformly smooth Banach spaces. In this paper Kamimura and Takahashi's algorithm is extended to develop a generic inexact proximal point algorithm, and their convergence analysis is extended to develop a generic convergence analysis which unifies a wide class of proximal-type methods applied to finding the zeroes of maximal monotone operators in the setting of Hilbert spaces or Banach spaces.</p
Need for review of the ministerial directive concerning anti-rabies prophylaxis in the light of recent epidemiological evidence.
No full textWill be added ASA
On maximum and variational principles via image space analysis
No full textThe analysis in the Image Space allows one to extend the applications of maximum and variational principles for constrained optimization. Such principles are embedded in a separation scheme, in the Image Space, which can be seen as a common root from which they are derived. In particular, Ekeland and Auchmuty Variational Principles are analysed
Modeling Declassification Policies using Abstract Domain Completeness
No full textThis paper explores a three dimensional characterisation of a declassification-basednon-interference policy and its consequences. Two of the dimensions consist of specifying:(a) the power of the attacker, that is, what public information a program has that anattacker can observe; and(b) what secret information a program has that needs to be protected.Both these dimensions are regulated by the third dimension:(c) the choice of program semantics, for example, trace semantics or denotationalsemantics, or any semantics in Cousot’s semantics hierarchy.To check whether a program satisfies a non-interference policy, one can compute an abstractdomain that over-approximates the information released by the policy and then checkwhether program execution can release more information than permitted by the policy.Counterexamples to a policy can be generated by using a variant of the Paige–Tarjanalgorithm for partition refinement. Given the counterexamples, the policy can be refined sothat the least amount of confidential information required for making the program secure isdeclassified
- …
