scholarly journals A PDEVS simulator supporting multiple synchronization protocols: implementation and performance analysis

SIMULATION ◽  
2017 ◽  
Vol 94 (4) ◽  
pp. 281-300 ◽  
Author(s):  
Ben Cardoen ◽  
Stijn Manhaeve ◽  
Yentl Van Tendeloo ◽  
Jan Broeckhove
Keyword(s):  
Simulation Models ◽  
Performance Gain ◽  
Simulation Tools ◽  
Advantages And Disadvantages ◽  
External Component ◽  
And Performance ◽  
Optimistic Synchronization ◽  
Time Bounds ◽  
Sequential Implementation ◽  
Synchronization Protocol

With the ever-increasing complexity of simulation models, parallel simulation becomes necessary to perform simulation within reasonable time bounds. The built-in parallelism of Parallel DEVS is often insufficient to tackle this problem on its own. Several synchronization protocols have been proposed, each with their distinct advantages and disadvantages. Due to the significantly different implementation of these protocols, most Parallel DEVS simulation tools are limited to only one such protocol. In this paper, we present a Parallel DEVS simulator, grafted on C++11 and based on PythonPDEVS, supporting both conservative and optimistic synchronization protocols. The simulator not only supports both protocols but also has the capability to switch between them at runtime. The simulator can combine each synchronization protocols with either a threaded or sequential implementation of the PDEVS protocol. We evaluate the performance gain obtained by choosing the most appropriate synchronization protocol. A comparison is made to adevs in terms of CPU time and memory usage, to show that our modularity does not hinder performance. We compare the speedup obtained by synchronization with that of the inherent parallelism of PDEVS in isolation and combination, and contrast the results with the theoretical limits. We further allow for an external component to gather simulation statistics, on which runtime switching between the different synchronization protocols can be based. The effects of allocation on our synchronization protocols are also studied.

MODERN EQUIPMENT FOR DETERMINING TRACTOR-SPEED PROPERTIES OF THE VEHICLE: CHARACTERISTICS’ ANALYSIS IN LABORATORY CONDITIONS

2019 ◽  
Vol 16 (3) ◽  
pp. 276-289
Author(s):  
N. V. Savenkov ◽  
V. V. Ponyakin ◽  
S. A. Chekulaev ◽  
V. V. Butenko
Keyword(s):  
Environmental Performance ◽  
Operating Conditions ◽  
Special Role ◽  
Development Stages ◽  
Advantages And Disadvantages ◽  
Force Transfer ◽  
Characteristics Analysis ◽  
And Performance ◽  
Loading Devices ◽  
Structural Solutions

Introduction. At present, stands with running drums are widely used for various types of tests. Power stands play a special role. Such stands take the mechanical power from the driving wheels of the car. This simulates the process of movement of the vehicle under operating conditions. Such equipment has various designs, principles of operation and performance. It is also used in tests that are different by purpose, development stages and types: research, control, certification, etc. Therefore, it is necessary in order to determine the traction-speed, fuel-efficient and environmental performance characteristics.Materials and methods. The paper provides the overview of the power stands with running drums, which are widespread on the domestic market. The authors carried out the analysis of the main structural solutions: schemes of force transfer between the wheel and the drum; types of loading devices; transmission layout schemes and features of the control and measuring complex. The authors also considered corresponding advantages and disadvantages, recommended spheres of application, demonstrated parameters and characteristics of the units’ workflow, presented components and equipment.Discussion and conclusions. The authors critically evaluate existing models of stands with running drums. Such information is useful for choosing serial models of stands and for developing technical tasks for designing or upgrading the equipment.

scholarly journals Six Key Advantages and Disadvantages of Working from Home in Europe during COVID-19

2021 ◽  
Vol 18 (4) ◽  
pp. 1826
Author(s):  
Christine Ipsen ◽  
Marc van Veldhoven ◽  
Kathrin Kirchner ◽  
John Paulin Hansen
Keyword(s):  
Knowledge Work ◽  
Well Being ◽  
Key Factors ◽  
Differential Impact ◽  
Home Office ◽  
Negative Experience ◽  
Number Of Children ◽  
Advantages And Disadvantages ◽  
Working From Home ◽  
And Performance

The number of people working from home (WFH) increased radically during the coronavirus (COVID-19) pandemic. The purpose of this study was therefore to investigate people’s experiences of WFH during the pandemic and to identify the main factors of advantages and disadvantages of WFH. Data from 29 European countries on the experiences of knowledge workers (N = 5748) WFH during the early stages of lockdown (11 March to 8 May 2020) were collected. A factor analysis showed the overall distribution of people’s experiences and how the advantages and disadvantages of WFH during the early weeks of the pandemic can be grouped into six key factors. The results indicated that most people had a more positive rather than negative experience of WFH during lockdown. Three factors represent the main advantages of WFH: (i) work–life balance, (ii) improved work efficiency and (iii) greater work control. The main disadvantages were (iv) home office constraints, (v) work uncertainties and (vi) inadequate tools. Comparing gender, number of children at home, age and managers versus employees in relation to these factors provided insights into the differential impact of WFH on people’s lives. The factors help organisations understand where action is most needed to safeguard both performance and well-being. As the data were collected amidst the COVID-19 pandemic, we recommend further studies to validate the six factors and investigate their importance for well-being and performance in knowledge work.

Hider: A Methodology for Early-Stage Exploration of Design Space

1996 ◽  
Author(s):  
Sudhakar Y. Reddy
Keyword(s):  
Design Space ◽  
Optimization Problems ◽  
Early Stage ◽  
Simulation Models ◽  
Design Tool ◽  
System Level ◽  
Complex Simulation ◽  
Machine Learning Approach ◽  
Detailed Simulation ◽  
And Performance

Abstract This paper describes HIDER, a methodology that enables detailed simulation models to be used during the early stages of system design. HIDER uses a machine learning approach to form abstract models from the detailed models. The abstract models are used for multiple-objective optimization to obtain sets of non-dominated designs. The tradeoffs between design and performance attributes in the non-dominated sets are used to interactively refine the design space. A prototype design tool has been developed to assist the designer in easily forming abstract models, flexibly defining optimization problems, and interactively exploring and refining the design space. To demonstrate the practical applicability of this approach, the paper presents results from the application of HIDER to the system-level design of a wheel loader. In this demonstration, complex simulation models for cycle time evaluation and stability analysis are used together for early-stage exploration of design space.

scholarly journals Closest and long-term prospects of 3D-printing for obstetrics and gynecology

2021 ◽  
Vol 20 (1) ◽  
pp. 76-81
Author(s):  
E. V. Kudryavtseva ◽  
V. V. Kovalev ◽  
E. S. Zakurinova ◽  
G. Muller-Kamskii ◽  
V. V. Popov
Keyword(s):  
3D Printing ◽  
Scientific Literature ◽  
Simulation Models ◽  
Surgical Instruments ◽  
Obstetrics And Gynecology ◽  
Scientific Review ◽  
Advantages And Disadvantages ◽  
The Creation ◽  
Dimensional Printing

Introduction. Despite the notable and rapid progress in the development of medical 3D printing in recent years, not much is known about the use of this technology in obstetrics and gynecology.The purpose of our review of scientific literature was to determine the current level of 3D printing development, discuss the closest and long term prospects for using this technology in obstetrics and gynecology, and analyze its potential advantages and disadvantages.Materials and methods. We searched for scientific literature. 378 papers passed a three-step screening, as a result of which 42 sources were selected for the final scientific review.Results and discussion. The main areas in which dimensional printing can be used in this area of medicine is the creation of simulation models and training for students, the creation of anatomical models for preoperative preparation, the surgical instruments, the creation of new dosage drug forms (including transvaginal ones), and bioprinting of organs and tissues.Conclusion. The presented literary review allows us to conclude that 3D printing the obstetrics and gynecology is a current rapidly developing direction. The organization of 3D modeling and printing laboratories can significantly increase the efficiency of teaching students and residents. In addition, obstetricians-gynecologists and surgeons should be informed about the possibility of 3D printing surgical instruments according to an individual design. It can inspire them to implement their own ideas and develop domestic innovative developments. Three-dimensional printing of dosage forms and bioprostheses requires more complex technological solutions, and is not yet used in clinical practice. However, given the enormous prospects for these areas, various grants should be envisaged for their development in Russia

scholarly journals A critical review on the development and performance of polymer/graphene nanocomposites

2018 ◽  
Vol 25 (6) ◽  
pp. 1059-1073 ◽  
Author(s):  
Weifeng Chen ◽  
Hu Weimin ◽  
Dejiang Li ◽  
Shaona Chen ◽  
Zhongxu Dai
Keyword(s):  
Polymer Nanocomposites ◽  
Electronic Conductivity ◽  
Future Research ◽  
Preparation Methods ◽  
Graphene Nanocomposites ◽  
Advantages And Disadvantages ◽  
Solution Blending ◽  
Potential Applications ◽  
New Type ◽  
And Performance

AbstractGraphene (graphene) is a new type of two-dimensional inorganic nanomaterial developed in recent years. It can be used as an ideal inorganic nanofiller for the preparation of polymer nanocomposites because of its high mechanical strength, excellent electrical conductivity and plentiful availability (from graphite). In this review, the preparation methods of graphene/polymer nanocomposites, including solution blending, melt blending and in situ polymerization, are introduced in order to study the relationship between these methods and the final characteristics and properties. Each method has an influence on the final characteristics and properties of the nanocomposites. The advantages and disadvantages of these methods are discussed. In addition, a variety of nanocomposites with different properties, such as mechanical properties, electronic conductivity, thermal conductivity and thermal properties, are summarized comprehensively. The potential applications of these nanocomposites in conductive materials, electromagnetic shielding materials, photocatalytic materials and so on, are briefly presented. This review demonstrates that polymer/graphene nanocomposites exhibit superior comprehensive performance and will be applied in the fields of new materials and novel devices. Future research directions of the nanocomposites are also presented.

scholarly journals Task-based programming in COMPSs to converge from HPC to big data

2017 ◽  
Vol 32 (1) ◽  
pp. 45-60 ◽  
Author(s):  
Javier Conejero ◽  
Sandra Corella ◽  
Rosa M Badia ◽  
Jesus Labarta
Keyword(s):  
Big Data ◽  
High Performance ◽  
Programming Model ◽  
Good Alternative ◽  
Programming Models ◽  
Suitable Model ◽  
Advantages And Disadvantages ◽  
Big Data Applications ◽  
And Performance ◽  
The Right

Task-based programming has proven to be a suitable model for high-performance computing (HPC) applications. Different implementations have been good demonstrators of this fact and have promoted the acceptance of task-based programming in the OpenMP standard. Furthermore, in recent years, Apache Spark has gained wide popularity in business and research environments as a programming model for addressing emerging big data problems. COMP Superscalar (COMPSs) is a task-based environment that tackles distributed computing (including Clouds) and is a good alternative for a task-based programming model for big data applications. This article describes why we consider that task-based programming models are a good approach for big data applications. The article includes a comparison of Spark and COMPSs in terms of architecture, programming model, and performance. It focuses on the differences that both frameworks have in structural terms, on their programmability interface, and in terms of their efficiency by means of three widely known benchmarking kernels: Wordcount, Kmeans, and Terasort. These kernels enable the evaluation of the more important functionalities of both programming models and analyze different work flows and conditions. The main results achieved from this comparison are (1) COMPSs is able to extract the inherent parallelism from the user code with minimal coding effort as opposed to Spark, which requires the existing algorithms to be adapted and rewritten by explicitly using their predefined functions, (2) it is an improvement in terms of performance when compared with Spark, and (3) COMPSs has shown to scale better than Spark in most cases. Finally, we discuss the advantages and disadvantages of both frameworks, highlighting the differences that make them unique, thereby helping to choose the right framework for each particular objective.

Hot Isostatic Processing

2004 ◽  
pp. 55-60
Keyword(s):  
Aluminum Alloy ◽  
Hot Isostatic Pressing ◽  
High Quality ◽  
Advantages And Disadvantages ◽  
Radiographic Inspection ◽  
Hot Isostatic Processing ◽  
Alloy Castings ◽  
And Performance ◽  
Hip Process ◽  
Very High

Abstract Hot isostatic pressing (HIP) is a process refinement available to address internal porosity in castings. The HIP process may be used, in particular, for applications requiring very high quality and performance. This chapter discusses the principles, advantages, and disadvantages of HIP. It describes the effect of HIP on tensile properties and on the fatigue performance of aluminum alloy castings. In addition, the chapter discusses the processes involved in radiographic inspection of HIP-processed castings.

A Comparative Study on a Built Sun Tracker and Fixed Converter Panels

2012 ◽  
Vol 1 (4) ◽  
pp. 56-69
Author(s):  
Farzin Shama ◽  
Gholam Hossein Roshani ◽  
Sobhan Roshani ◽  
Arash Ahmadi ◽  
Saber Karami
Keyword(s):  
Renewable Energy ◽  
Power Plants ◽  
Large Scale ◽  
Human Society ◽  
Renewable Energy Resources ◽  
Advantages And Disadvantages ◽  
Production And Consumption ◽  
Solar Power Plants ◽  
And Performance ◽  
Optimization And Performance

Producing non-polluting renewable energy in large scale is essential for sustainability of future developments in industry and human society. Among renewable energy resources, solar energy takes a special place because of its free accessibility and affordability. However, the optimization of its production and consumption processes poses important concerns, essentially in the affordability issue. This paper investigates several optimization and performance issues regarding solar panel converters using two-axis controlled solar tracer that has been practically implemented in comparison with fixed converter panels. Results shown in tables and graphs demonstrate clearly the advantages and disadvantages of the methods. Based on these results, large scale solar power plants are being suggested to be equipped with similar devices.

scholarly journals Distributed processing in virtual simulation using Cloud Computing Environment

2018 ◽  
Vol 210 ◽  
pp. 04018
Author(s):  
Jarosław Koszela ◽  
Maciej Szymczyk
Keyword(s):  
Cloud Computing ◽  
Distributed Processing ◽  
Simulation Models ◽  
Virtual Simulation ◽  
Performance Tests ◽  
Computing Environment ◽  
Computing Power ◽  
Cloud Computing Environment ◽  
Detailed Simulation ◽  
And Performance

Today’s hardware has computing power allowing to conduct virtual simulation. However, even the most powerful machine may not be sufficient in case of using models characterized by high precision and resolution. Switching into constructive simulation causes the loss of details in the simulation. Nonetheless, it is possible to use the distributed virtual simulation in the cloud-computing environment. The aim of this paper is to propose a model that enables the scaling of the virtual simulation. The aspects on which the ability to disperse calculations depends were presented. A commercial SpatialOS solution was presented and performance tests were carried out. The use of distributed virtual simulation allows the use of more extensive and detailed simulation models using thin clients. In addition, the presented model of the simulation cloud can be the basis of the “Simulation-as-a-Service” cloud computing product.

scholarly journals A STUDY TO EXPLORE LEARNING STYLE PREFERENCES OF PHARMACY STUDENTS WITH REGARD TO PHARMACEUTICAL CALCULATIONS

2019 ◽  
pp. 88-96
Author(s):  
BAHTA WARA ◽  
JAN DALY ◽  
HANA MORRISSEY ◽  
PATRICK BALL
Keyword(s):  
Learning Styles ◽  
Learning Style ◽  
Test Session ◽  
Drug Dose ◽  
Formative Assessments ◽  
Pharmacy Students ◽  
Learning Preference ◽  
Advantages And Disadvantages ◽  
And Performance ◽  
Teaching Learning

Objective: Pharmaceutical calculations are an essential aspect of learning for pharmacy students in order to avoid drug dose errors and maintain patient safety in future practice. Learning styles influence how lecturers approach the teaching-learning process. So far no specific learning preference is believed to be most appropriate for the pharmacy curricular; however certain learning styles are favoured by students as they improve their understanding of course material, knowledge and performance. Methods: 148Master of pharmacy participants from the second and third year were given a questionnaire to complete during a compulsory Individual Readiness Assurance Test session. Participants were restricted to just one option. Results: Workshops with a tutor was the most selected (36%) followed by 25% of participants favouring formative assessments, 28% selected workbooks alone, 37% for whole-class lecturers and videos option was the least selected. Reasons for the most and least preferred learning styles were highlighted and separated into advantages and disadvantages using themes. In the knowledge test; 92% of participants selected “unsure” or “didn’t know” the answer, 29% had a partially correct answer and 19% selected incorrect answers. The overall order of ranking arose in regards to the most beneficial learning style which enhances performance. The responses revealed a variety of advantages and disadvantages which were reflected between year groups and similar to views obtained from recent literature. Students reflected a lack of understanding on extemporaneous preparation (EPs) terms used in pharmaceutical compounding practices, thus the university should consider addressing the lack of awareness and consider the best teaching-learning style in doing so. Conclusion: Overall the findings suggested that the sample students have similar views on the learning styles used to deliver pharmaceutical calculations on their academic performance to that expressed by the authors from recent published literature.

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