Top PDF HyLTL: a temporal logic for model checking hybrid systems

HyLTL: a temporal logic for model checking hybrid systems

HyLTL: a temporal logic for model checking hybrid systems

Hybrid systems exhibit both a discrete and a continuous behaviour with a tight interaction between the two. Typical examples include discrete controllers that operate in a continuous environment, like auto- motive power-train systems, where a four stroke engine is modeled by a switching continuous system and is controlled by a digital controller. In order to model and specify hybrid systems in a formal way, the no- tion of hybrid automata has been introduced [1, 9, 14]. Intuitively, a hybrid automaton is a “finite-state automaton” with continuous variables that evolve according to dynamics characterizing each discrete state (called a location or mode). Of particular importance in the analysis of hybrid automata is the model checking problem, that is, the problem of verifying whether a given hybrid automaton respects some property of interest. The state of a hybrid automaton consists of the pairing of a discrete location with a vector of continuous variables, therefore it has the cardinality of continuum. This makes the model checking problem computationally difficult. Indeed, even for very simple properties and systems, this problem is not decidable [10].
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Probabilistic and Hybrid Model Checking Deployments for
Wireless Sensor Networks

Probabilistic and Hybrid Model Checking Deployments for Wireless Sensor Networks

Real-Time Maude is one of the significant tools for development of general object-oriented systems compatible for modelling a network. Reachability analysis for timed search, linear temporal logic model checking and timed rewriting for simulation purposes are included in the number of analysis techniques supported by Real- Time Maude. It permits the specification, exploration of broad range of scenarios, modelling of appropriate forms of communication and testing of various behaviours on simulation tools directly because if its ability of flexible formal specification. It supports the specification of advanced systems using various data types with self- expression by equational specifications and instantaneous transitions by rewrite rules [27]. OGDC (Optimal Geographical Density Control) algorithm is discussed in [28], which is using Real-Time Maude for its formal modelling and analysis. A number of behaviours related to OGDC density control algorithm are analyzed at the abstract level by specifying informal specifications. The given results confirmed that modelling and analysis of OGDC in Maude offers more accuracy in various situations with much less effort than a simulation tool.
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Model Checking the Biological Model of Membrane Computing with Probabilistic Symbolic Model Checker by Using Two Biological Systems

Model Checking the Biological Model of Membrane Computing with Probabilistic Symbolic Model Checker by Using Two Biological Systems

properties stated in the specification. The system’s specification is represented by using temporal logic formulas and symbolic algorithms are used to navigate the model to check if the specification is fulfilled or not. In recent time with the rapid research developments in Systems Biology, the use of model checking for the analysis of biological models has attracted much attention. Some of the research are: The analysis of transcriptional regulation by LTL model checking (Barnat et al., 2009); Performing statistical model checking using Bayesian sequential hypothesis Testing on biological systems (Sumit et al., 2009); algorithmic algebraic model checking on metabolic networks (Mysore and Mishra, 2007); temporal logic analysis of Gene Networks (Batt et al., 2007) and probabilistic model checking of complex biological pathways(Heath et al., 2006; Kwiatkowska et al., 2008).
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Abordagens paralelas para Model Checking de redes de autômatos estocásticos

Abordagens paralelas para Model Checking de redes de autômatos estocásticos

The use of critical and complex systems at automation of daily tasks increases the people’s de- pendence, generating unease about the safety of such systems. In the last years several techniques have been developed to facilitate activities related to design validation in the early stages of the development cycle. Model Checking is an automatic formal technique that allows verification of finite-state concurrent systems under properties described in temporal logics by employing verifica- tion algorithms that exhaustively assess the correctness of the system under consideration. Indeed, this technique is costly with respect to storage and processing, justifying the development of parallel and distributed algorithms for powerful computing clusters. This dissertation reports the study and development of verification algorithms for models described in Stochastic Automata Networks and properties written in Computation Tree Logic temporal logic for environments that address memory spaces in a distributed way.
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Model-Checking an Alternating-time Temporal Logic with Knowledge, Imperfect Information, Perfect Recall and Communicating Coalitions

Model-Checking an Alternating-time Temporal Logic with Knowledge, Imperfect Information, Perfect Recall and Communicating Coalitions

In our previous work models are based on interpreted systems as known from [FHMV04]. In that setting global system states are tuples which consist of the local views of the individual agents and the satisfaction of atomic propositions at a global state need not be related to the local views in it. Unlike that, in this paper we assume that the view of each agent is described as a set of atomic propositions which the agent can observe. States which satisfy the same observable atomic propositions are indistinguishable to the agent. Observability as in interpreted systems can be simulated in this concrete observability semantics. However, the converse does not hold, see [Dim10] for details.
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A Hybrid 3D Indoor Space Model

A Hybrid 3D Indoor Space Model

In the most of the above discussed researches, precise and up-to-date geometrical models are vital. This research investigates to propose new methodology to overcome the need of required precise geometrical models for the derivation of topological model. 3D indoor navigation modeling requires a valid 3D model that can be represented as a cell complex: a model without any gap or intersection such that two cells (e.g. room, corridor) perfectly touch each other.

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Lat. Am. j. solids struct.  vol.13 número15

Lat. Am. j. solids struct. vol.13 número15

ing system (Flores et al., 2011; Erkaya and Uzmay, 2010). The composition of testing platform is based on the transmission mechanism of a high speed press system, which includes motor, crank shaft, fly wheel, linkages, main slider and balancing mechanism. The main slider of the high speed press system, as shown in Fig. 1, is chosen as test object. Due to the acceleration cannot be showed directly, the data processing system is installed into the PC to facilitate the analysis of the testing data. Moreover, the acquisition and analysis systems are established into the BeeTech software, which can transform data at any time. In order to collect the acceleration data accurately, we cali- brate the acceleration sensor before testing. Furthermore, the experiment is conducted under the unloading condition and two periods of acceleration are employed to comparisons between numeri- cal results and experimental data, which is more effective to depict the validity of proposed meth- odology. The parameters of kinematic and dynamic for the planar multibody system are presented in Table 1.
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HYBRID TRUST MODEL FOR INTERNET ROUTING

HYBRID TRUST MODEL FOR INTERNET ROUTING

In general, our reputation based model is not inherently capable of detecting BGP misconfigurations and attacks itself. It is only useful when deployed in conjunction with the collection of available tools for debugging local networks. The positive trade-off, though, is that the architecture itself is agnostic to a specific problem in question, allowing any trust-related proposition to be weighted and voted on. With further research and tuning the trust components smartly, the protocol works well if a minority of participants act maliciously.
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An Efficient Explicit-time Description Method for Timed Model Checking

An Efficient Explicit-time Description Method for Timed Model Checking

Timed model checking, the method to formally verify real-time systems, is attracting increasing atten- tion from both the model checking community and the real-time community. Explicit-time descrip- tion methods verify real-time systems using general model constructs found in standard un-timed model checkers. Lamport proposed an explicit-time description method [17] using a clock-ticking process (Tick) to simulate the passage of time together with a group of global variables to model time requirements. Two methods, the Sync-based Explicit-time Description Method using rendezvous synchronization steps and the Semaphore-based Explicit-time Description Method using only one global variable were proposed [27, 26]; they both achieve better modularity than Lamport’s method in modeling the real-time systems. In contrast to timed automata based model checkers like UPPAAL [7], explicit-time description methods can access and store the current time instant for future calcula- tions necessary for many real-time systems, especially those with pre-emptive scheduling. However, the Tick process in the above three methods increments the time by one unit in each tick; the state spaces therefore grow relatively fast as the time parameters increase, a problem when the system’s time period is relatively long. In this paper, we propose a more efficient method which enables the Tick process to leap multiple time units in one tick. Preliminary experimental results in a high perfor- mance computing environment show that this new method significantly reduces the state space and improves both the time and memory efficiency.
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Molecular dynamics simulation in hybrid systems

Molecular dynamics simulation in hybrid systems

The MD hybrid version consisted in using both the shared and distributed memory models in the implementation. This implementation eliminates the main limitation of the OpenMP code since the available resources are not limited to a single node. The MPI implementation had already solved this limitation, but an hybrid implementation allows a much higher performance in some cases. For example, when there is a lot of communication between processes and when there are few critical sections. In our code we benefit a little from each model. We can reduce the time spent in communication, because we have less processes that need to communicate, we also use less memory space because with threads it uses shared memory and because we have few critical sections the execution seldom blocks in these sections.
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An alternating direction algorithm for hybrid precoding and combining in millimeter wave MIMO systems

An alternating direction algorithm for hybrid precoding and combining in millimeter wave MIMO systems

In this work we have addressed the hybrid design problem for spatial multiplexing in mmWave MIMO systems using an augmented Lagrangian based decomposition method. The adopted approach results in an iterative algorithm comprising a sequence of smaller subproblems with straightforward solutions. The precoding/combining design algorithm can work with a broad range of configuration of antennas, RF chains and data streams. Furthermore, different versions of the algorithm were proposed for the fully-connected and partially-connected hybrid precoding structures, as well as for a OFDM-based mmWave system operating in frequency selective channels. Simulation results show that the proposed method is capable of performing close to the optimal fully digital design, with a better
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Derivation Methods for Hybrid Knowledge Bases with Rules and Ontologies

Derivation Methods for Hybrid Knowledge Bases with Rules and Ontologies

Considering the query c(X), X is grounded to object by the predicate p which, again, assures DL-safety. In a first inner iteration, a(object), p(object) and c(object) succeed; simul- taneously, the ontology is not able to prove anything since the proposition A does not hold. In the end of this iteration, the two components share knowledge as described in Definition 5.10. In a second inner iteration the rules maintain what they inferenced before and the ontology derives A. After sharing this knowledge, there is no more to infer by either components, and a fixpoint is reached. When the inner fixpoint is reached, we end the first outer iteration. So now, the second outer iteration will start the computation of the inner iteration again and, in this iteration, nots are evaluated given the last outer iteration. As a consequence, c(object) fails, since b(object) is proved in the latter iteration. The inner iteration fixes by inferring p(object), a(object) and b(object), which is in fact the correct model for the object object. Afterwards, the outer iteration needs one more computational in order to stop, returning the model described. Since c(object) is in the model, the query c(X) returns true for X = object.
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Some methods for sensitivity analysis of systems / networks

Some methods for sensitivity analysis of systems / networks

A network may considerably change with certain nodes, links, flows, or parameters. To find the most important nodes, links, or other parameters to determine network structure or performance is of significant. Sensitivity analysis is originated from systems science. It explores the relationship between parametric change and systematic output, and is used to find important parameters in the system model. In principle, the sensitivity analysis used in systems science can also be extended to network analysis in which the model output means network output, network stability, network flow, network structure, or other indices, and model input means network nodes, network links, network parameters, etc. In present article, some methods for sensitivity analysis of systems / networks are described in detail.
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User Assistance Characteristics of the USE Model Checking Tool

User Assistance Characteristics of the USE Model Checking Tool

The Unified Modeling Language (UML) is a widely used general purpose modeling language. To- gether with the Object Constraint Language (OCL), formal models can be described by defining the structure and behavior with UML and additional OCL constraints. In the development process for formal models, it is important to make sure that these models are (a) correct, i.e. consistent and com- plete, and (b) testable in the sense that the developer is able to interactively check model properties. The USE tool (UML-based Specification Environment) allows both characteristics to be studied. We demonstrate how the tool supports modelers to analyze, validate and verify UML and OCL models via the use of several graphical means that assist the modeler in interpreting and visualizing formal model descriptions. In particular, we discuss how the so-called USE model validator plugin is inte- grated into the USE environment in order to allow non domain experts to use it and construct object models that help to verify properties like model consistency.
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An Advanced Certain Trust Model Using Fuzzy  Logic and Probabilistic Logic theory

An Advanced Certain Trust Model Using Fuzzy Logic and Probabilistic Logic theory

Abstract—Trustworthiness especially for service oriented system is very important topic now a day in IT field of the whole world. Certain Trust Model depends on some certain values given by experts and developers. Here, main parameters for calculating trust are certainty and average rating. In this paper we have proposed an Extension of Certain Trust Model, mainly the representation portion based on probabilistic logic and fuzzy logic. This extended model can be applied in a system like cloud computing, internet, website, e-commerce, etc. to ensure trustworthiness of these platforms. The model uses the concept of fuzzy logic to add fuzziness with certainty and average rating to calculate the trustworthiness of a system more accurately. We have proposed two new parameters - trust T and behavioral probability P, which will help both the users and the developers of the system to understand its present condition easily. The linguistic variables are defined for both T and P and then these variables are implemented in our laboratory to verify the proposed trust model. We represent the trustworthiness of test system for two cases of evidence value using Fuzzy Associative Memory (FAM). We use inference rules and defuzzification method for verifying the model.
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Begin, After, and Later: a Maximal Decidable Interval Temporal Logic

Begin, After, and Later: a Maximal Decidable Interval Temporal Logic

We considered an interval temporal logic (ABBL) with four modalities, corresponding, respectively, to Allen’s interval relations after, begins, begun-by, and before, and interpreted in the class of all strongly discrete linearly ordered sets, which includes, among others, all frames built over N, Z, and finite orders. We showed that this logic is decidable in EXPSPACE, and complete for this class. The importance of this result relies on the fact that, for the considered interpretations, this logic is maximal with respect to decidability. Moreover, these results represent a non-trivial contribution towards the complete classifica- tion of all fragments of Halpern and Shoham’s modal logic of intervals. We plan to complete the study of this particular language when it is interpreted over other classes of orders, such as the class of all dense linearly ordered sets, or the class of all linear orders, and to refine these results to include point-intervals, too.
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Hybrid Intelligent Model for Software Maintenance Prediction

Hybrid Intelligent Model for Software Maintenance Prediction

The choice of an AI technique model for maintainability is not solely and necessarily depending on the strength of the model but on the ease of finding prediction and building accurate models [3]. There have been many attempts to build solutions based on GA but unfortunately they can’t be applied in practical environments due to the assumption of infinity time or resources. Moreover, some authors justify the applicability of GA to their problems based on seemingly fruitful results without considering the reasons, limits or implicit assumptions in the target problem.
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A hybrid simulation model for a stable auroral arc

A hybrid simulation model for a stable auroral arc

beams self-consistently in a two-dimensional setting. Wave- particle interactions of electrons are not self-consistently in- cluded in the model but effects describing them can be added in the manner described below. Our model contains the same physics as the one-dimensional models of Ergun et al. (2000) and Schriver et al. (2001), except for the omission of elec- tron kinetic effects which, however, are not essential for the questions we study here. Because of our assumption that magnetospheric ions are very hot, we cannot expect to re- produce the double transition layer feature of Ergun et al. (2000). The advantages of our model are that it contains full ion kinetics and two spatial dimensions together with the possibility of studying the global effects of assumed elec- tron wave-particle interactions. With our model we cannot, however, describe the magnetospheric auroral arc powering mechanism self-consistently as the MHD simulations do; en- ergy input from the magnetosphere is contained in the as- sumed electron anisotropy caused by wave-induced parallel energisation. The development of a new type of ion pusher (“monopole solver”) increases the efficiency of our model considerably and thus increases its practical applicability. We verify that the model produces the observational satellite signatures of an inverted-V region such as ion beams, con- vergent electric fields, parallel electric fields and an auroral density depletion. In this paper we use the model for study- ing the closure of the potential contours and the lifetime of auroral density depletions after the inverted-V precipitation that created them has disappeared.
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PERFORMANCE EVALUATION OF HYBRID FUZZY LOGIC CONTROLLER FOR BRUSHLESS DC MOTOR DRIVE

PERFORMANCE EVALUATION OF HYBRID FUZZY LOGIC CONTROLLER FOR BRUSHLESS DC MOTOR DRIVE

This paper presents Hybrid fuzzy logic controller (HFLC) for the well developed and sophisticated simulation model of Brush less DC (BLDC) motor drive using MATLAB. The developed simulation model has been examined by the PID controller and HFLC. The performance of the controllers is evaluated more precisely from various simulation studies for variations in the load torque and speed of BLDC motor drive. A performance comparison of two controllers is also carried out by taking various performance measures such as settling time, steady state error, peak overshoot, the integral of the absolute value of the error (IAE) and the integral of the time-weighted squared error (ITSE). The results confirm that the developed simulation model is very convenient for the precise evaluation of performance and the HFLC shows improved performance over the PID controller in terms of disturbance rejection or parameter variation.
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Model of knowledge representation about materials in the form of a relational database for CAPCAST system

Model of knowledge representation about materials in the form of a relational database for CAPCAST system

Checking the dependency of attributes is done to omit the un- necessary attributes, the step which can be of crucial importance in optimising the decision-making process. A smaller number of attributes means less of a dialogue with the user and quicker search of the rule base looking for adequate procedure of reason- ing. In the case of decision tables that contain very large sets of redundant attributes (created during the operations associated with data mining), the possibilities of reduction can become critical elements in building of a knowledge base. A totally different situation occurs when the decision table is created by knowledge engineers in a controlled manner, based on e.g. literature, expert knowledge, and/or standards, when the set of attributes is authori- tatively created basing on the available knowledge about the phenomena. In this case, the reduction of attributes is not neces- sary, as it can be assumed that the number of unnecessary attributes (if any) shall not deteriorate the model classificability.
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