Search results for "Variable"
showing 10 items of 1674 documents
Qualitative models of equipment units and their use in automatic HAZOP analysis
2000
Abstract The use of qualitative models in a support system for HAZOP analyses, in connection with an algorithm for finding the causes and the consequences of variable deviations, is described. The models use several representation structures among which mini-trees constitute the most important from the logical-functional point of view. The models are conceived both for continuous and batch plants. For the latter procedures, regulating the use of equipment units are also modelled using similar structures while equipment units are considered in various phases of their functioning. A brief description of the prototype support system, in which the models are implemented, is also given.
Parallelization of adaptive MC integrators
1997
Monte Carlo (MC) methods for numerical integration seem to be embarassingly parallel on first sight. When adaptive schemes are applied in order to enhance convergence however, the seemingly most natural way of replicating the whole job on each processor can potentially ruin the adaptive behaviour. Using the popular VEGAS-Algorithm as an example an economic method of semi-micro parallelization with variable grain-size is presented and contrasted with another straightforward approach of macro-parallelization. A portable implementation of this semi-micro parallelization is used in the xloops-project and is made publicly available.
ISTehnology - Metamodel based approach to information system development
2014
Document describes experience of using metamodel-based tool ISTehnology in development of information systems. The author of this document is one of the developers of ISTehnology. The main goal of the research is to figure out the framework (methodology and tools) for building information systems able to work in variable business environment and easy changeable. ISTechnology is such a framework. The document describes a metamodel of ISTehnology, approach to information systems development, advantages and disadvantages of its usage and possibilities to prevent disadvantages by using modern graphical tools of modeling.
Different Methods of Artificial Intelligence Used for Optimization the Turning Process
2015
In this paper, we realize a comparative study between some heuristics methods applied in turning operation in order to find optimal cutting parameters. We consider five different constraints aimed to achieve minimum total cost of machining. We have chosen the Simulated Annealing (SA) – a local search method, and Weighted-Sum Genetic Algorithm (WSGA) – a non-Pareto approach of a multi-objective optimization algorithm, based on a weighted aggregation of objectives. The aggregation may be with fixed weights or with random (variable) weights. The simulations showed that, even if it produces better results than the SA, WSGA with fixed weights, does not lead to optimum results, highlighting in th…
Nowcasting Global Economic Growth: A Factor-Augmented Mixed-Frequency Approach
2014
Facing several economic and financial uncertainties, assessing accurately global economic conditions is a great challenge for economists. The International Monetary Fund proposes within its periodic World Economic Outlook report a measure of the global GDP annual growth, that is often considered as the benchmark nowcast by macroeconomists. In this paper, we put forward an alternative approach to provide monthly nowcasts of the annual global growth rate. Our approach builds on a Factor-Augmented MIxed DAta Sampling (FA-MIDAS) model that enables (i) to account for a large monthly database including various countries and sectors of the global economy and (ii) to nowcast a low-frequency macroec…
De Se as Variable Binding: On Context-Sensitivity in Utterance Reports
2020
In this paper I will be defending a view of de se attitudes according to which all the inaccuracies attributed to Kaplan’s Logic of Demonstratives having to do with the nature of de se attitude reports follow a single pattern: they are argued to correspond to bound uses of the variables contributed by the pronouns. I will argue that a traditional view of propositions suffices for dealing with these phenomena from a linguistic point of view.
Joint Alignment and Modeling of Correlated Behavior Streams
2013
The Variable Time-Shift Hidden Markov Model (VTS- HMM) is proposed for learning and modeling pairs of cor- related streams. Unlike previous coupled models for time series, the VTS-HMM accounts for varying time shifts be- tween correlated events in pairs of streams having different properties. The VTS-HMM is learned on a set of pairs of unaligned streams and, thus, learning entails simultaneous estimation of the varying time shifts and of the parameters of the model. The formulation is demonstrated in the analysis of videos of dyadic social interactions between children and adults in the Multimodal Dyadic Behavior Dataset (MMDB). In dyadic social interactions, an agent starts an interaction …
Improved route planning and scheduling of waste collection and transport
2006
The collection of waste is a highly visible and important municipal service that involves large expenditures. Waste collection problems are, however, one of the most difficult operational problems to solve. This paper describes the optimization of vehicle routes and schedules for collecting municipal solid waste in Eastern Finland. The solutions are generated by a recently developed guided variable neighborhood thresholding metaheuristic that is adapted to solve real-life waste collection problems. Several implementation approaches to speed up the method and cut down the memory usage are discussed. A case study on the waste collection in two regions of Eastern Finland demonstrates that sign…
Fuzzy logic and meteorological variables: a case study of solar irradiance
2002
Solar irradiance is an extreme case of an uncertain variable when measured on an hourly, or shorter time interval. In this paper solar irradiance has been considered as a case study for physical fuzzy modelling of a climate variable. The uncertainty of the solar irradiance is treated as a fuzzy uncertainty whilst other variables are considered crisp. The approach is robust as it does not rely on statistical assumptions, and it is a possible alternative to modelling complex systems. To our knowledge, this is the first time that a physical model of a meteorological variable based on fuzzy numbers has been proposed. Previous rule-based fuzzy meteorological models are only descriptive, and cann…
Distributed ASM - Pitfalls and solutions
2014
Published version of a chapter in the book: Abstract State Machines, Alloy, B, TLA, VDM, and Z. Also available from the publisher at: http://dx.doi.org/10.1007/978-3-662-43652-3_18 While sequential Abstract State Machines (ASM) capture the essence of sequential computation, it is not clear that this is true of distributed ASM. This paper looks at two kinds of distributed process, one based on a global state and one based on variable access. Their commonalities are extracted and conclusions for the general understanding of distributed computation are drawn, providing integration between global state and variable access.