Verification and Validation of D2FD Method

International audience—D2FD (Data to Fuzzy-DEVS) method provides a solution for the problem of system inference. This method is well designed and implemented as an available and dedicated plug-in within the process mining framework (ProM). This plug-in is also integrated with the simulation tool SimStudio. However, the last step of the process of inferring models and simulations, which is verification and validation, is missing. This paper proposes a new paradigm of verification and validation in system inference. The case study uses the method of comparing with other models as the main validation technique. Based on the same data source from the Dutch Employee Insurance Agency, it attempts to compare the previous results with other studies

Modeling and simulation enabled UAV electrical power system design

With the diversity of mission capability and the associated requirement for more advanced technologies, designing modern unmanned aerial vehicle (UAV) systems is an especially challenging task. In particular, the increasing reliance on the electrical power system for delivering key aircraft functions, both electrical and mechanical, requires that a systems-approach be employed in their development. A key factor in this process is the use of modeling and simulation to inform upon critical design choices made. However, effective systems-level simulation of complex UAV power systems presents many challenges, which must be addressed to maximize the value of such methods. This paper presents the initial stages of a power system design process for a medium altitude long endurance (MALE) UAV focusing particularly on the development of three full candidate architecture models and associated technologies. The unique challenges faced in developing such a suite of models and their ultimate role in the design process is explored, with case studies presented to reinforce key points. The role of the developed models in supporting the design process is then discussed

Cost Analysis for Crushing and Screening – Part II

Sandvik SRP has earlier studied a new way of calculating the cost in crushing and screening the results was a satisfactory, Sandvik SRP is now ready to go further in this study. The purpose of this study is further develop of the earlier adopted generic cost model earlier developed by Heyman and Lindström in order to calculate the cost per metric ton within the world of crushing and screening. By implementing the cost calculation in Microsoft excel it would be more user friendly and applicable when calculating the cost in crushing and screening. The model by Hayman and Lindstöm is based on the macroeconomic generic cost-model, developed and published by Ståhl. Heyman and Lindstöm developed a new model to fit the crushing and screening operations better. This model had some issues according to the payroll cost and the deprecation cost which the author now have solved in this study. By implement the cost model in Microsoft Excel by using VBA (Visual Basic for Application) the calculations and simulations can be easy to use when most of the employees are well familiar with Microsoft Excel. To implement the model and to programming all macros that is used is very time consuming and this is the largest part of this study. The results through this study were very accurate according to the results from previous study but the validation was an issue. To validate this study the comparison has been made with Heyman and Lindström results from the previous study. They had such good results and a more quantitative study was not made according to lack of time. The recommendation from the results according to this study is to validate the model even further and not at least for a construction site before further implementation in for example Plant Designer etc

Simulation

Welcome to this graduate course on Discrete-Event Simulation, a hybrid discipline that combines knowledge and techniques from Operations Research (OR) and Computer Science (CS) (Figure 1). Due to the fast and continuous improvements in computer hardware and software, Simulation has become an emergent research area with practical industrial and services applications. Today, most real-world systems are too complex to be modeled and studied by using analytical methods. Instead, numerical methods such as simulation must be employed in order to study the performance of those systems, to gain insight into their internal behavior and to consider alternative (“what-if”) scenarios. Applications of Simulations are widely spread among different knowledge areas, including the performance analysis of computer and telecommunication systems or the optimization of manufacturing and logistics processes. This course introduces concepts and methods for designing, performing and analyzing experiments conducted using a Simulation approach. Among other concepts, this course discusses the proper collection and modeling of input data and system randomness, the generation of random variables to emulate the behavior of the real system, the verification and validation of models, and the analysis of the experimental outputs. FigurePeer ReviewedPostprint (published version

Application of dynamic priorities for controlling the characteristics of a queuing system

This paper considers the development and modification of an imitation model of a queuing system. The initial model uses the laws of control (discipline of expectation and service) with mixed priorities. The work investigates the model with three types of entities (absolute priority, relative priority and priority-free ones) in the regime of overload, i.e. a system with losses. Verification and validation of the created imitation model confirmed its adequateness and accuracy of received results. The application of dynamic priorities for changing the laws of model control substantially alters certain system characteristics. The creation of the model in MatLab Simulink environment with the use of SimEvents and Stateflow library modules allowed creating a fairly complex queuing system and obtain new interesting results

Application of dynamic priorities for controlling the characteristics of a queuing system

This paper considers the development and modification of an imitation model of a queuing system. The initial model uses the laws of control (discipline of expectation and service) with mixed priorities. The work investigates the model with three types of entities (absolute priority, relative priority and priority-free ones) in the regime of overload, i.e. a system with losses. Verification and validation of the created imitation model confirmed its adequateness and accuracy of received results. The application of dynamic priorities for changing the laws of model control substantially alters certain system characteristics. The creation of the model in MatLab Simulink environment with the use of SimEvents and Stateflow library modules allowed creating a fairly complex queuing system and obtain new interesting results

Simulation on Network Security Design Architecture for Server Room in Rwanda Information Technology Agency

Today, computer networks attacks have continued to increase in severity and sophistication. Data lost and unavailability of network resources due to attacks from internet have negative financial impact on many companies. Unprotected organisation’s networks from internet attacks face high risk of data loss and espionage. Network devices that make up network are the most targeted in order to penetrate in companies system as some come with vulnerability from the manufacturer. In this study, network security architecture for server room had been developed for enhancing the security. Further, two simulation models had been developed to compare the throughput for both existing and developed security architecture

Cost comparison of orthopaedic fracture pathways using discrete event simulation in a Glasgow hospital

Objective: Healthcare faces the continual challenge of improving outcome whilst aiming to reduce cost. The aim of this study was to determine the micro cost differences of the Glasgow non-operative trauma virtual pathway in comparison to a traditional pathway. Design:  Discrete event simulation was used to model and analyse cost and resource utilisation with an activity based costing approach. Data for a full comparison before the process change was unavailable so we utilised a modelling approach, comparing a Virtual Fracture Clinic (VFC) to a simulated Traditional Fracture Clinic (TFC). Setting:  The orthopaedic unit VFC pathway pioneered at Glasgow Royal Infirmary has attracted significant attention and interest and is the focus of this cost study. Outcome measures: Our study focused exclusively on non-operative trauma patients attending Emergency Department or the minor injuries unit and the subsequent step in the patient pathway. Retrospective studies of patient outcomes as a result of the protocol introductions for specific injuries in association with activity costs from the models.ResultsPatients are satisfied with the new pathway, the information provided and the outcome of their injuries (Evidence Level IV). There was a 65% reduction in the number of first outpatient face-to-face attendances in orthopaedics. In the VFC pathway, the resources required per day were significantly lower for all staff groups (p=<0.001). The overall cost per patient of the VFC pathway was £22.84 (95% CI: 21.74, 23.92) per patient compared with £36.81 (95% CI: 35.65, 37.97) for the TFC pathway.  Conclusions:  Our results give a clearer picture of the cost comparison of the virtual pathway over a wholly traditional face-to-face clinic system. The use of simulation-based stochastic costings in healthcare economic analysis has been limited to date, but this study provides evidence for adoption of this method as a basis for its application in other healthcare settings

Уніфікована схема реалізації оптимізаційно-імітаційних експериментів

Представлено базований на концепції оптимізаційно-імітаційної інтеграції підхід до реалізації імітаційного інструментарію та відповідного програмного середовища на основі дискретно-подійної системи НЕДИС-Р, метаевристичного оптимізатора та уніфікованої схеми пошуку оптимальних рішень щодо задач аналізу, модернізації або проектування складних систем. Зазначений підхід забезпечує скорочення витрат часових та фінансових ресурсів на проведення експериментів. Розглянуто перспективи подальшого розвитку такого підходу.Here is presented the approach based on the concept of optimization-simulation integration to implement the simulation toolkit and the corresponding environment on the platform of discrete event simulation system NEDIS-R, metaheuristic optimizer and unified scheme for search of optimal decisions concerning problems of analysis, modernization or designing of complex systems. The specified approach provides reduction of time and financial expenses for experiments realizations. The perspectives of further development of such approach are considered