Simulation Language Research Articles

Overview of the LTE network and removal of unwanted Handover in the network and how to implement it with the ns3 simulator

Today, cellular networks, notably LTE, are used in substructure communications because of ease of launch, tranquil maintenance, the movable equipment, the communal accessed, and other services. LTE has superior improvement in efficiency, higher data rates, lower time lag, cost savings, capacity, and coverage. How to categorize BTS antennas and handover at the border points are main consequence in these networks. there is possibility to set unessential handover indoors. Also ability to eliminate unnecessary handovers and optimized the networks structure. As a response, several scenarios, such as using the SOM neural network, the X-means clustering algorithm, ICA colonial competition algorithm , and other innovative and meta-innovative algorithms are introduced. Setting up, testing, and evaluating need to a simulated environment. In this research, we tried to examine this type of the LTE network and the its Handover, by analyze the tools’ feature and network simulation languages such as (NS-2, NS-3, OMNET ++), we can present the right choice. Then, we will examine the possibility of implementing LTE and Handover scenarios in NS-3.

Simulation of electromagnetic transients with Modelica, accuracy and performance assessment for transmission line models

Electromagnetic Transient (EMT) simulation tools are typically developed using an imperative language. It is typically required to code the models using a specific numerical integration method and following existing solution algorithms. On the other hand, modern high-level, acausal and equation-based programming languages, such as Modelica, allow to formulate models that are easy to read, understand and develop by expressing what needs to be computed without stating how it should be computed. In this paper, the application of Modelica to EMT modeling is demonstrated and the benefits of the language for EMT-type simulations is established. This is done by using the declarative language concept for the development of two models, namely the Constant Parameter (CP) and the Wide-Band (WB) models. Two case studies are presented and used to validate the models and to compare accuracy and performance.

Verifying Properties of MapReduce-Based Big Data Processing

Big data techniques are widely used in various fields. To deal with large data sets efficiently, a new programming framework MapReduce has emerged. Thus, new verification challenges arise to improve the reliability of big data processing. In this article, MapReduce processes are implemented by modeling simulation and verification language programs. Then, several data properties such as data soundness, nonconflict, nonduplication, cooperation, and completeness are taken into account. Moreover, these properties are specified by propositional projection temporal logic formulas. To verify these properties, a runtime verification approach at code level based on unified model checking is employed. In addition, two case studies are conducted to demonstrate our approach: sparse matrix multiplication and tracking down suspected patients of an infectious disease.

Theoretical and Practical Approaches to the Denotational Semantics for MDESL based on UTP

AbstractThe hardware description language Verilog has been standardized and widely used in industry. Multithreaded Discrete Event Simulation Language (MDESL) is a Verilog-like language and it contains a rich variety of interesting features such as the event-driven computation and shared-variable concurrency as well as the realtime feature. In this paper, we present the denotational semantics for MDESL based on UTP. First a discrete time semantic model is proposed to describe the observation-oriented semantics for MDESL. The observations record the change of variables of atomic actions over time. Then the healthy formulae are defined to denote all different behaviors of programs and the semantics of programs is expressed in terms of healthy formulae. In addition, we demonstrate some interesting properties about the MDESL programs expressing as algebraic laws and their proofs are supported by our formalized denotational semantics. Our theoretical approach is complemented by a practical one, we use the theorem proof assistant Coq to formalize the UTP-based semantics for MDESL. The correctness of the algebraic laws is also verified via the mechanical approach in Coq. Our work provides a novel way to verify the correctness of UTP-based semantics forMDESL both in a theoretical approach and in a practical approach. It is also a new attempt for the application of Coq in the mechanized semantics.

Modeling Resources to Simulate Business Process Reliability

The combination of process modeling and simulation-based analysis provides a quantitative approach to analyze business processes, and to evaluate design alternatives before committing the required resources, to properly align operations with business strategies, improve operational efficiency, and gain competitive advantage. However, the use of simulation-based analysis is still limited in practice, mainly because it does not exploit process modeling standards and typically addresses performance-related properties only, such as time and cost. This article proposes a methodology that first extends the standard language for process modeling (i.e., BPMN) to introduce a flexible and accurate specification of business process resources, and then exploits the extended process specification to analyze and predict the process behavior by use of a simulation approach that takes into account reliability-related properties, to consider unexpected failures of process resources. The simulation-based analysis is implemented by use of a domain-specific process simulation language that preserves the BPMN execution semantics. An example application is introduced to show the importance of addressing both performance and reliability properties for the simulation-based analysis of business processes.

SIMSCRIPT: A Programming Language for Military Simulation

SIMSCRIPT is high-level simulation language with a long history and world-wide acceptance, especially in the field of military simulation. The paper first introduces the SIMSCRIPT world-view and its simulation mechanism, which lay the basis for its success, and next points out the language’s prominent advantages from the viewpoint of a military modeler, and also lists its weaknesses which are yet to be improved, and then proposes suggestions to better utilize the capability of the simulation language, and last discusses the development trend of SIMSCRIPT.

The Simulation of Heat Propagation Rate in Smart Roasting Process Using Finite Difference Method

In the industrial 4.0 era, there have been many developments in daily equipment that have been transformed into more sophisticated tools both in terms of how they are used, the efficiency of their work and the quality of the results obtained due to the digitization process that is easily accessed by many people. Therefore, As the early step, the paper discusses the computational modeling in the automatic cooking methods, namely the smart roaster system. The cooking method in the form of granules by using a roasting process, which generally utilizes heated sand, is interesting to learn since there are two mechanisms of heat propagation from the pan to the food object, namely the mechanism of heat propagation by conduction and radiation, but in this study, the heat propagation due to temporary convection was ignored. The first mechanism is accommodated by Fourier's Law, while the second is by Stefan-Boltzmann's Law. For simplification, the system is discussed in one dimension with the same grain size, but the object can have a different size. The composition of the pan walls, grains of sand, empty space, and food objects can be randomized so that various configurations can be created. Discussed how the process of heat propagation can occur in the roasting process and also radiation to the surrounding space on the top of the sand surface. The numerical analysis method is used with the finite difference method and the Matlab programming language for simulation.

Real-Time Hardware in the Loop Simulation Methodology for Power Converters Using LabVIEW FPGA

Nowadays, the use of the hardware in the loop (HIL) simulation has gained popularity among researchers all over the world. One of its main applications is the simulation of power electronics converters. However, the equipment designed for this purpose is difficult to acquire for some universities or research centers, so ad-hoc solutions for the implementation of HIL simulation in low-cost hardware for power electronics converters is a novel research topic. However, the information regarding implementation is written at a high technical level and in a specific language that is not easy for non-expert users to understand. In this paper, a systematic methodology using LabVIEW software (LabVIEW 2018) for HIL simulation is shown. A fast and easy implementation of power converter topologies is obtained by means of the differential equations that define each state of the power converter. Five simple steps are considered: designing the converter, modeling the converter, solving the model using a numerical method, programming an off-line simulation of the model using fixed-point representation, and implementing the solution of the model in a Field-Programmable Gate Array (FPGA). This methodology is intended for people with no experience in the use of languages as Very High-Speed Integrated Circuit Hardware Description Language (VHDL) for Real-Time Simulation (RTS) and HIL simulation. In order to prove the methodology’s effectiveness and easiness, two converters were simulated—a buck converter and a three-phase Voltage Source Inverter (VSI)—and compared with the simulation of commercial software (PSIM® v9.0) and a real power converter.

A novel approach to verifying context free properties of programs

This paper proposes an approach to verifying context free properties of programs. In this approach, the system to be verified is modeled as a program m in Modeling, Simulation and Verification Language (MSVL), and the desired property is also specified by an MSVL program m′. Then program m and formula ¬m′ are interpreted by means of executing programs m and m′. If an acceptable execution path is generated, a counterexample is found, otherwise the property is valid. To show how the proposed approach works, an example is given.

Translating Xd-C programs to MSVL programs

C language is one of the most popular languages for software systems. In order to verify safety, reliability and security properties of such systems written in C, a tool UMC4M for runtime verification at code level based on Modeling, Simulation and Verification Language (MSVL) and its compiler MC is employed. To do so, a C program P has to be translated to an MSVL program M and the negation of a desired property Q is also translated to an MSVL program M', then “M and M'” is compiled and executed armed with MC. Whether P violates Q is checked by evaluating whether there exists an acceptable execution of new MSVL program “M and M'”. Therefore, how to translate a C program to an MSVL program is a critical issue. However, in general, C is of complicated structures with goto statement. In this paper, we confine the syntax of C in a suitable subset called Xd-C without loss of expressiveness. Further, we present a translation algorithm from an Xd-C program to an MSVL program based on translation algorithms for expressions and statements. Moreover, the equivalences between expressions and statements involved in Xd-C and MSVL programs are inductively proved. Subsequently, the equivalence between the original Xd-C program and the translated MSVL program is also proved. In addition, the proposed approach has been implemented by a tool called C2M. A benchmark of experiments including 13 real-world Xd-C programs is conducted. The results show that C2M works effectively.

Molly reborn in C++ and R

The dairy cow model ‘Molly’ is a mixed discrete event-continuous system model that simulates feeding, metabolism and lactation of dairy cows. Decades of model development have resulted in a valuable tool in dairy science. Due to the deprecation of the ACSL (Advanced Continuous Simulation Language) programming language, Molly has been translated into C++. This paper describes the translation process and discusses the advantages of the new implementation, one of which is the ability to run Molly within RStudio, a popular integrated development environment (IDE) for data science.

Use of simulation by modelling of conveyor belt contact forces

Abstract Intelligent conveyors include a large number of sensors and also signalling devices. So-called digital twin presents an advantage that creates a virtual image of a real conveyor. Simulation of the conveyor by simulation language can be an example of a tool of a conveyor virtual image. Simulation allows to test the proposed changes and in the case of functionality, to use the changes in the real operation of pipe conveyor. The paper presents the description of the simulated regression model of conveyor and realized simulation experiments within the regression model of pipe conveyor.

An efficient variable-node XFEM for modeling multiple crack growth: A Matlab object-oriented implementation

We present a Matlab object-oriented implementation of an efficient variable-node extended finite element method (XFEM) for multiple crack growth simulation in brittle materials. To enhance the accuracy of the present method, not only the local mesh refinement strategy is used, but also the variable-node elements are adopted to directly link different scale elements, saving the computational cost. In order to efficiently conduct coalescence detection, a modification is also presented. A stability analysis is performed to determine active crack tips, and the crack length control scheme is employed to model multiple crack growth. Mesh is locally refined simultaneously with the extension of cracked area via a straightforward manner. A general computer program structure for the Matlab object-oriented programming code for the variable-node XFEM is described. All those desirable features of the present work are demonstrated through five numerical examples with branching in linear-elastic fracture mechanics. In addition, this work provides an efficient computer code written by Matlab programming language for computational fracture simulation, which is for educational and academic uses.

SBML2Modelica: integrating biochemical models within open-standard simulation ecosystems.

SBML is the most widespread language for the definition of biochemical models. Although dozens of SBML simulators are available, there is a general lack of support to the integration of SBML models within open-standard general-purpose simulation ecosystems. This hinders co-simulation and integration of SBML models within larger model networks, in order to, e.g. enable in silico clinical trials of drugs, pharmacological protocols, or engineering artefacts such as biomedical devices against Virtual Physiological Human models. Modelica is one of the most popular existing open-standard general-purpose simulation languages, supported by many simulators. Modelica models are especially suited for the definition of complex networks of heterogeneous models from virtually all application domains. Models written in Modelica (and in 100+ other languages) can be readily exported into black-box Functional Mock-Up Units (FMUs), and seamlessly co-simulated and integrated into larger model networks within open-standard language-independent simulation ecosystems. In order to enable SBML model integration within heterogeneous model networks, we present SBML2Modelica, a software system translating SBML models into well-structured, user-intelligible, easily modifiable Modelica models. SBML2Modelica is SBML Level 3 Version 2-compliant and succeeds on 96.47% of the SBML Test Suite Core (with a few rare, intricate and easily avoidable combinations of constructs unsupported and cleanly signalled to the user). Our experimental campaign on 613 models from the BioModels database (with up to 5438 variables) shows that the major open-source (general-purpose) Modelica and FMU simulators achieve performance comparable to state-of-the-art specialized SBML simulators. SBML2Modelica is written in Java and is freely available for non-commercial use at https://bitbucket.org/mclab/sbml2modelica.

Formal verification with HiLLS-specified models: A further step in multi-analysis modeling of complex systems

The multi-analysis modeling of a complex system is the act of building a family of models which allows to cover a large spectrum of analysis methods (such as simulation, formal methods, enactment,[Formula: see text]) that can be performed to derive various properties of this system. The High-Level Language for Systems Specification (HiLLS) has recently been introduced as a graphical language for discrete event simulation, with potential for other types of analysis, like enactment for rapid system prototyping. HiLLS defines an automata language that also opens the way to formal verification. This paper provides the building blocks for such a feature. That way, a unique model can be used not only to perform both simulation and enactment experiments but also to allow the logical analysis of properties without running any experiment. Therefore, it saves from the effort of building three different analysis-specific models and the need to align them semantically.

Experimentation of a methodology to use modelling and simulation in the analysis of performances of an automotive industry production system

The simulation is almost always used as an integrated part of a system design process, as method to identify the improvements of an existing process, to evaluate an already developed model to find alternative solution for it or to compare working hypothesis. It represents an experimental technique that allows experimentation on models of the real system created using a specific simulation language. The knowledge accumulated during the experimentation on the model can be useful and applicable on the real system. Considering that, when it comes to talking about modelling and simulation it is talked about building a model of a real system and the experimentation possible on it. In this paper we will experiment a methodology to simulate the operating mode of a production system from the automotive industry, formed of several interconnected stages. The techniques and instruments used to make the activities in this methodology are in the fields of flow analysis and comparative analysis.

Verifying Full Regular Temporal Properties of Programs via Dynamic Program Execution

Verification of programs at code level has attracted more and more attentions since the cost is high to extract models from source code. Most of approaches available for code level verification are carried out by inserting assertions into programs and then checking whether the assertions are violated. In this way, only safety properties can be verified, however, other temporal properties of programs such as liveness are hard to be verified. To tackle this problem, a novel runtime verification approach, which can verify full regular temporal properties of a program, is proposed in this paper. With this approach, a program to be verified is written in a modeling, simulation and verification language (MSVL) as a program M and a desired property is specified by a propositional projection temporal logic formula $P$ . The negation of the desired property is then translated to an MSVL program M’ . Thus, whether M violates $P$ can be checked by evaluating whether there exists an acceptable execution of the new MSVL program “ M and M’ .” This problem can efficiently be solved with the MSVL compiler where verification cases are generated via dynamic symbolic execution. Further, we adopt parallel mechanism to handle various execution paths of a program for improving the efficiency. The proposed approach has been implemented in a tool called MSV . Experiments show that the performance of MSV outperforms existing tools such as T2, RiTHM, and LTLAutomizer in verifying temporal properties of real-world programs.

Theoretical and Practical Aspects of Linking Operational and Algebraic Semantics for MDESL

Verilog is a hardware description language (HDL) that has been standardized and widely used in industry. Multithreaded discrete event simulation language (MDESL) is a Verilog-like language. It contains interesting features such as event-driven computation and shared-variable concurrency. This article considers how the algebraic semantics links with the operational semantics for MDESL. Our approach is from both the theoretical and practical aspects. The link is proceeded by deriving the operational semantics from the algebraic semantics. First, we present the algebraic semantics for MDESL. We introduce the concept of head normal form. Second, we present the strategy of deriving operational semantics from algebraic semantics. We also investigate the soundness and completeness of the derived operational semantics with respect to the derivation strategy. Our theoretical approach is complemented by a practical one, and we use the theorem proof assistant Coq to formalize the algebraic laws and the derived operational semantics. Meanwhile, the soundness and completeness of the derived operational semantics is also verified via the mechanical approach in Coq. Our approach is a novel way to formalize and verify the correctness and equivalence of different semantics for MDESL in both a theoretical approach and a practical approach.

Physiologically-based pharmacokinetic modeling of benzo(a)pyrene and the metabolite in humans of different ages

ABSTRACT Age-specific differences in the pharmacokinetics of benzo(a)pyrene (BaP) and its metabolite 3-hydroxybenzo(a)pyrene (3-OHBaP) potentially affect time courses of tissue concentration; however, the quantitative impact of these differences is not well characterized. Our objective was to quantify the effect of age-specific differences in physiological and biochemical parameters on the pharmacokinetics of BaP and 3-OHBaP from newborn at birth to adulthood following inhalation exposure. The time courses of BaP and 3-OHBaP were simulated by using a physiologically based pharmacokinetic model with Advanced Continuous Simulation Language (ACSLX). The concentrations of BaP increased with age in the liver but decreased with age in most tissues, urine, and blood. The concentrations of 3-OHBaP were the highest in the newborns. Our results also showed that the concentration of BaP has almost reached a steady state in the kidney, liver, lung, rapidly perfused tissues, slowly perfused tissues, and skin except for adipose tissues. However, the concentration of 3-OHBaP has reached a steady state in all tissues. This study suggests that age-specific parameters have an effect on the pharmacokinetics of BaP and 3-OHBaP. In particular, tissue concentration in the newborns is higher than other age groups, which indicates that the newborns are susceptible to environmental BaP exposure.

Research and Organization of Priority Modes in a Network Distributed Computing System with Cloud Service Architecture

Purpose of research.The object of the study is a network cloud service built on the basis of a replicated database. Data in distributed computing systems are replicated in order to ensure the reliability of their storage, facilitate access to data as well as to improve the storage system performance. In this regard, the problem of analyzing the effectiveness of processing the queries to replicated databases in a network-based cloud environment, and, in particular, the problem of organizing priority query queues for updating databae copies (update requests) and for searching and reading information in databases (query-requests). The purpose of this work is to study and organize priority modes in a network distributed computing system with cloud service architecture.Methods.The study was conducted on the basis of two types of behavioural patterns: models based on Petri nets to describe and verify the functioning of a distributed computing system with replicated databases represented as a pool of resource units with several units, and models based on the GPSS simulation language for possible evaluation of passage of query time of each type in queues depending on the priority of queries.Results.Based on two simulation methods, the operation of a cloud system with database replicas was analyzed. In this system two distributed cloud computing systems interact: MANET Cloud based on a wireless network and Internet Cloud based on the Internet. These databases together are the basis of the DBaaSoD (Data Bases as a Service on Demand) cloud service (databases as a service organized at user’s query). To study this system the models of two classes were developed. The model based on Petri nets is designed to test the simulated distributed application for proper functioning. The decisions on the mapping of Petri nets on the architecture of computer networks are discussed. The simulation statistical model is used to compare the priority and non-priority maintenance modes of query- and update-requests by the criterion of average passage of time of queries in queues.Conclusion.System models based on Petri nets were tested, which showed their liveness and security, which makes it possible to move from models to building formalized specifications for network applications for network cloud services in distributed computing systems with replicated databases. The study of GPSS-model showed that in the case of priority service of update-requests, the time of passage for them is reduced by about 2 to 4 times compared with query-requests, depending on the intensity of the query-requests. In the non-priority mode, the serving conditions for update-queries deteriorate and the time of passage in the queue for them increases by about 2 to 6 times as compared with query-requests depending on the intensity of the query-requests.