scholarly journals A DEVS-based pivotal modeling formalism and its verification and validation framework

SIMULATION ◽  
2020 ◽  
Vol 96 (12) ◽  
pp. 969-992
Author(s):  
Kehinde G Samuel ◽  
Nourou-Dine M Bouare ◽  
Oumar Maïga ◽  
Mamadou K Traoré

System verification is an ever-lasting system engineering challenge. The increasing complexity in system simulation requires some level of expertise in handling the idioms of logic and discrete mathematics to correctly drive a full verification process. It is recognized that visual modeling can help to fill the knowledge gap between system experts and analysis experts. However, such an approach has been used on the one hand to specify the behavior of complex systems, and on the other hand to specify complex requirement properties, but not simultaneously. This paper proposes a framework that is unique in supporting a full system verification process based on the graphical modeling of both the system of interest and the requirements to be checked. Patterns are defined to transform the resulting models to formal specifications that a model checker can manipulate. A real-time crossing system is used to illustrate the proposed framework.

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Sana Shuja ◽  
Sudarshan K. Srinivasan ◽  
Shaista Jabeen ◽  
Dharmakeerthi Nawarathna

Pacemakers are safety-critical devices whose faulty behaviors can cause harm or even death. Often these faulty behaviors are caused due to bugs in programs used for digital control of pacemakers. We present a formal verification methodology that can be used to check the correctness of object code programs that implement the safety-critical control functions of DDD mode pacemakers. Our methodology is based on the theory of Well-Founded Equivalence Bisimulation (WEB) refinement, where both formal specifications and implementation are treated as transition systems. We develop a simple and general formal specification for DDD mode pacemakers. We also develop correctness proof obligations that can be applied to validate object code programs used for pacemaker control. Using our methodology, we were able to verify a control program with millions of transitions against the simple specification with only 10 transitions. Our method also found several bugs during the verification process.


2018 ◽  
Vol 6 (1) ◽  
pp. 146
Author(s):  
Thomas Frölich ◽  
F F Bevier ◽  
Alicja Babakhani ◽  
Hannah H Chisholm ◽  
Peter Henningsen ◽  
...  

To address subjectivity, as a generally rooted phenomenon, other ways of visualisation must be applied than in conventional objectivistic approaches. Using ‘trees’ as operational metaphors, as employed in Arthur Cayley’s ‘theory of the analytical forms called trees’, one rooted ‘tree’ must be set beneath the other and, if such ‘trees’ are combined, the resulting ‘forest’ is nevertheless made up of individual ‘trees’ and not of a deconstructed mix of ‘roots’, ‘branches’, ‘leaves’ or further categories, each understood as addressable both jointly and individually. The reasons for why we have chosen a graph theory and corresponding discrete mathematics as an approach and application are set out in this first of our three articles. It combines two approaches that, in combination, are quite uncommon and which are therefore not immediately familiar to all readers. But as simple as it is to imagine a tree, or a forest, it is equally simple to imagine a child blowing soap bubbles with the aid of a blow ring. A little more challenging, perhaps, is the additional idea of arranging such blow rings in series, transforming the size of the soap bubble in one ring after the other. To finally combine both pictures, the one of trees and the other of blow rings, goes beyond simple imagination, especially when we prolong the imagined blow ring becoming a tunnel, with a specific inner shape. The inner shape of the blow ring and its expansion as a tunnel are understood as determined by discrete qualities, each forming an internal continuity, depicted as a scale, with the scales combined in the form of a glyph plot. The different positions on these scales determine their length and if the endpoints of the spines are connected with an enveloping line then this corresponds to the free space left open in the tunnel to go through it. Using so many visualisation techniques at once is testing. Nevertheless, this is what we propose here and to facilitate such a visualisation within the imagination, we do it step by step. As the intended result of this ‘juggling of three balls’, as it were, we end up with a concept of how living beings elaborate their principal structure to enable controlled outside-inside communication.


Author(s):  
Sergey Tiurin ◽  
◽  

In the wave of the green computing trend, research has recently intensified on the so-called adiabatic logic, reversible computing, which is supposed to be the basis of quantum computers and bring to a new level of computing power, combined with low power consumption. The basis of this logic is special reversible gates, for example, Fredkin’s gates. Reversibility is a one-to-one correspondence (bijection) between the inputs and outputs of circuits, which means, on the one hand, the possibility of total control of the results of calculations, and on the other hand, the possibility of returning the obtained "energy" quanta for the perform calculations to their source. This approach can significantly reduce the power consumption of computers, as well as increase the reliability of calculations. There are a lot of publications on this topic, however, the development of universal logic modules on such a basis has not been fully considered. The aim of the study is the development and modeling of universal logic modules based on the Fredkin element. In this case, the methods of logical synthesis of a reversible scheme based on a binary Fredkin element, modeling and analysis of billiard calculations are used. The article presents the proposed schemes of the decoder and multiplexer based on the Fredkin element, the "billiard" simulation. The practical significance of the study lies in the fact that the obtained universal logic modules can be used in the synthesis of binary reversible circuits, for example, FPGAs. The performed simulation can be used as examples in practical exercises in the discrete mathematics, mathematical logic, mathematical modeling, and circuitry disciplines.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Sheng Gao ◽  
Qianqian Su ◽  
Rui Zhang ◽  
Jianming Zhu ◽  
Zhiyuan Sui ◽  
...  

Traditional identity authentication solutions mostly rely on a trusted central entity, so they cannot handle single points of failure well. In addition, most of these traditional schemes need to store a large amount of identity authentication or public key information, which makes the schemes difficult to expand and use in distributed situations. In addition, the user prefers to protect the privacy of their information during the identity verification process. Due to the open and decentralized nature of the blockchain, the existing identity verification schemes are difficult to apply well in the blockchain. To solve this problem, in this article, we propose a privacy protection identity authentication scheme based on the blockchain. The user independently generates multiple-identity information, and these identities can be used to apply for an identity certificate. Authorities use the ECDSA signature algorithm and the RSA encryption algorithm to complete the distribution of the identity certificate based on the identity information and complete the registration of identity authentication through the smart contract on the blockchain. On the one hand, it can realize the protection of real identity information; on the other hand, it can avoid the storage overhead caused by the need to store a large number of certificates or key pairs. Due to the use of the blockchain, there is no single point of failure in the authentication process, and it can be applied to distributed scenarios. The security and performance analysis show that the proposed scheme can meet security requirements and is feasible.


Author(s):  
Ehtesham Zahoor ◽  
Kashif Munir ◽  
Olivier Perrin ◽  
Claude Godart

Traditional business process specification approaches such as BPMN are procedural, as they require specifying exact and complete process flow. In contrast, a declarative process is specified by a set of constraints that mark the boundary of any solution to the process. In this chapter, the authors propose a bounded model-checking-based approach for the verification of declarative processes using satisfiability solving (SAT). The proposed approach does not require exponential space and is very efficient. It uses the highly expressive event calculus (EC) as the modeling formalism, with a sound and complete EC to SAT encoding process. The verification process can include both the functional and non-functional aspects. The authors have also proposed a filtering criterion to filter the clauses of interest from the large set of unsatisfiable clauses for complex processes. The authors have discussed the implementation details and performance evaluation results to justify the practicality of the proposed approach.


2020 ◽  
Vol 69 (1) ◽  
pp. 414-417
Author(s):  
S.M. Sarsimbayeva ◽  

The article deals with the development of augmented reality applications on the Vuforia platform, the use this technology in the educational process for the purpose of visual modeling of educational material. The results of the analysis of existing approaches to the development of augmented reality applications, platforms, tool development environments such as Vuforia, with the ability to connect Unity, and the implementation of augmented reality technology are shown. The importance of using high-level augmented reality technologies, the prospects for using augmented reality technology, and the opportunities and advantages of using it in the educational process are highlighted. It is noted that the one of the promising areas of development of innovative educational technologies is the use of augmented reality in the learning process. An augmented reality application to Abay Kunanbayev's poems created on the basis of marker technology is proposed.


2009 ◽  
Vol 26 (01) ◽  
pp. 1-11 ◽  
Author(s):  
R. R. K. SHARMA ◽  
A. MURALIDHAR

In this paper a new formulation of the simple plant location problem (SPLP) is given that uses the style of Sharma and Sharma (European Journal of Operational Research, 122(3), 37–48). When the integer restrictions are relaxed, it results in a new relaxation of SPLP that is different from the already well known "strong" and "weak" relaxation of SPLP. It is shown that the bound given by the new relaxation is worse than the bound given by "strong relaxation" of SPLP. However, a numerical example illustrates that the bound given by the new relaxation can at times be better than the bound given by "weak relaxation" (already known) of SPLP. In this paper a new proof [which is different from the one given by Bilde and Krarup (Annals of Discrete Mathematics, 1, 79–97)] is given to establish relative strengths of various relaxations of SPLP.


Author(s):  
A. L. de Wet ◽  
T. W. von Backström ◽  
S. J. van der Spuy

The compressor section of a diesel locomotive turbocharger was re-designed to increase its maximum total-to-total pressure ratio and efficiency. Tests conducted on the prototype compressor showed possible rotating stall in the diffuser section before the designed higher pressure ratio could be achieved. It was decided to simulate the prototype compressor’s operation by using one-dimensional theory [1], followed by a three-dimensional CFD analysis of the compressor. This publication focuses on implementation of the impeller, vaneless annular passage and vaned diffuser one-dimensional theories. A verification process was followed to show the accuracy of the one- and three-dimensional modelling methods using two well-known centrifugal compressor test cases found in the literature [2–5]. Comparing the test case modelling results to available experimental results indicated sufficient accuracy to investigate the prototype compressor’s impeller and diffuser. Conclusions drawn on the prototype compressor’s performance using the one- and three-dimensional modelling methods led to a recommendation to redesign the impeller and diffuser of the prototype compressor.


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