Emulation Tool Research Articles

Evaluation and comparison of OpenDayLight and open networking operating system in software-defined networking

Software-defined networking (SDN) is a new way of transforming networks. It works on the principle of separating the infrastructure plane from the control plane. In the control plane, the centralized SDN controller acts as a brain of the network. Selecting the best SDN controller for the network is one of the most crucial tasks. In this paper, the experimental comparison between the two most powerful and popularly known SDN controllers on which many other SDN controllers are laid down their foundations i.e. OpenDayLight (ODL) and open networking operating system (ONOS) is performed. The experimentation is carried out on the Mininet emulation tool. Real-time packets are captured and analyzed using Wireshark. The results of the comparison concluded that the performance of the ODL controller is better than the ONOS in terms of burst rate, throughput, Round Trip Time (RTT) and bandwidth.

Performance analysis of emulated software defined wireless network

<table width="593" border="1" cellspacing="0" cellpadding="0"><tbody><tr><td valign="top" width="387"><p>Software defined wireless network is a networking architecture and an emerging networking principle that is based on software defined network. A software defined network is a fundamental networking concept which separates the networking devices used in communication network form the program that runs on the top of these devices. In this paper we will explore the modeling tools used for software defined wireless network in our literature survey and based on the survey we have used mininet-Wi-Fi for modeling software defined wireless network, which is the best and most widely used emulation tool for software defined wireless network. Lastly, we have evaluated the performance of TCP traffic bandwidth for different number of emulated end stations and access points.</p></td></tr></tbody></table>

AgROS: A Robot Operating System Based Emulation Tool for Agricultural Robotics

This research aims to develop a farm management emulation tool that enables agrifood producers to effectively introduce advanced digital technologies, like intelligent and autonomous unmanned ground vehicles (UGVs), in real-world field operations. To that end, we first provide a critical taxonomy of studies investigating agricultural robotic systems with regard to: (i) the analysis approach, i.e., simulation, emulation, real-world implementation; (ii) farming operations; and (iii) the farming type. Our analysis demonstrates that simulation and emulation modelling have been extensively applied to study advanced agricultural machinery while the majority of the extant research efforts focuses on harvesting/picking/mowing and fertilizing/spraying activities; most studies consider a generic agricultural layout. Thereafter, we developed AgROS, an emulation tool based on the Robot Operating System, which could be used for assessing the efficiency of real-world robot systems in customized fields. The AgROS allows farmers to select their actual field from a map layout, import the landscape of the field, add characteristics of the actual agricultural layout (e.g., trees, static objects), select an agricultural robot from a predefined list of commercial systems, import the selected UGV into the emulation environment, and test the robot’s performance in a quasi-real-world environment. AgROS supports farmers in the ex-ante analysis and performance evaluation of robotized precision farming operations while lays the foundations for realizing “digital twins” in agriculture.

Converter-Based Emulation of Battery Energy Storage Systems (BESS) for Grid Applications

Battery energy storage systems (BESSs) tend to be too costly, restrictive, and require high maintenance for experimental use, but power system tests often need their representation. As a solution, we propose an all-in-one, reconfigurable BESS emulation tool for grid applications that only requires one three-phase voltage-source converter. This emulator provides chemistry-specific battery behavior like previous work, but it also includes the BESS's power electronics interface and control as well as automatic frequency and voltage support functions for the attached power system. Thus, it allows simple, plug-and-play BESS emulation for grid applications. This paper details the construction, verification, and use of the BESS emulator in an existing grid testbed and concludes that it provides an inexpensive, easy-to-use alternative to using real BESSs in power system experiments.

Statistical validation of an LTE emulation tool using live video streaming over reliable transport protocols

Multimedia services such as Live Video-Streaming (LVS) or Video on Demand are the main drivers behind the notable traffic growth in cellular networks. This fact has attracted the interest of both academia and telcos in improving the end user’s quality of experience. For this reason, the development of test benches for conducting traffic studies in this type of telecommunication system is necessary and emulators are a good option to validate possible solutions without affecting the real systems. However, most works addressing the emulation of Long-Term Evolution (LTE) systems do not validate their outcomes with real environments and hence ignore critical parameters such as the impact of wireless propagation under different scenarios. Therefore, the goal of this paper is to validate an outdoor propagation model for LVS so that accurate studies of traffic characterization in LTE networks can be carried out using an emulation tool. The validation is done through a statistical analysis of variance (ANOVA) of Quality of Service metrics, comparing the results obtained in an LTE-emulated scenario with those obtained in a real LTE test bench. For this study, the LVS service runs on top of a reliable transport protocol. Specifically, we test the Real-Time Message Protocol and the MPEG Dynamic Adaptive Streaming over HTTP (DASH) protocol, both using TCP at the transport layer. According to the results, the propagation model that better matches the real environment under the considered conditions is the Nakagami-m propagation model with m = 5.

An adaptable and ISP-friendly multicast overlay network

Multicast is a group communication paradigm which aims at reducing, as much as possible, the amount of data generated into the network. Thus, IP Multicast presents itself as a technology that allows data to be distributed in such a way that the least amount of replicas of the same packet is placed into the network. However, the limited deployment of IP level Multicast protocols has lead to new approaches, in the application-level, implementing multicast using end systems and not routers. This concept has resulted in different approaches denominated as Application-Layer Multicast (ALM) or Overlay Multicast based systems. In this context, this work presents and analyzes an overlay multicast system envisioned to be highly reconfigurable and adaptable to different usability contexts. Such system versatility is not only present in the capability to construct distinct multicast distribution trees, but also in the integration of several advanced Traffic Engineering mechanisms based on collaborative efforts between the overlay and the Internet Service Provider (ISP) levels. Results from the proposed overlay system and associated mechanisms are obtained using a real system implementation which has been tested in a network emulation tool, with the experimental scenarios encompassing both single and multiple Autonomous Systems (AS).

Emulation of an Electric Naval Propulsion System Based on a Multiphase Machine Under Healthy and Faulty Operating Conditions

The main objective of this paper is the design of an Electric Naval Propulsion System (ENPS) emulator based on a low power multiphase machine. The whole drive system (control, power electronics, and electric machine) is tested and the mechanical part is emulated based on a Hardware-in-the-Loop principle. First, the modeling of all system components including mechanical and electrical parts are reviewed, and the total hull resistance forces are also developed. Then, a pure software simulation of the ENPS is carried out. After that, the designed emulator architecture is presented, and for adaption purpose, a scaling factor is introduced. The developed emulation tool allows to validate optimal control strategies for the propulsion system under a realistic navigation cycle under healthy and faulty operating conditions. Finally, simulation and experimental results are compared to investigate the accuracy and the performance of the developed emulator, and the effectiveness of the proposed control strategies.

Intelligent autonomous vehicles in digital supply chains

PurposeThe purpose of this paper is twofold: first, to discuss key challenges associated with the use of either simulation or real-world application of intelligent autonomous vehicles (IAVs) in supply network operations; and second, to provide a theoretical and empirical evidence-based methodological framework that supports the integrated application of conceptualisation, simulation, emulation and physical application of IAVs for the effective design of digital supply networks.Design/methodology/approachFirst, this study performs a critical review of the extant literature to identify major benefits and shortcomings related to the use of either simulation modelling or real-word application of physical IAVs. Second, commercial and bespoke software applications, along with a three-dimensional validation and verification emulation tool, are developed to evaluate an IAV’s operations in a conceptual warehouse. Third, a commercial depth-sensor is used as a test bed in a physical setting.FindingsThe results demonstrate that conceptual and simulation modelling should be initially used to explore alternative supply chain operations in terms of ideal performance while emulation tools and real-world IAV test beds are eminent in validating preferred digital supply chain design options.Research limitations/implicationsThe provided analysis framework was developed using literature evidence along with experimental work and research experience, without consulting any industry experts. In addition, this study was developed based on the application of a single physical device application as a test bed and, thus, the authors should further progress with the testing of a physical IAV in an industrial warehouse.Practical implicationsThe study provides bespoke simulation modelling and emulation tools that can be useful for supply chain practitioners in effectively designing network operations.Originality/valueThis work contributes in the operations management field by providing both a multi-stage methodological framework and a practical “toolbox” for the proactive assessment and incorporation of IAVs in supply network operations.

NeuroSpike viewer: A graphical environment for efficient control, communication and display of large-scale real-time simulation of Spiking Neural Networks on embedded systems

In recent years, the scientific community's interest for developing software or hardware tools capable of processing and displaying real-time simulations of large-scale Spiking Neural Networks (SNN) has been growing exponentially. Visualization of the simulations is crucial to observe and study the dynamics of the SNN, because these models involve high level of biological realism by encoding spatial-temporal information into action potentials or spikes like biological neurons do. Existing tools are based on supercomputers or customized neuromorphic architectures to compute large-scale SNN models. However, many of them are unsuitable to carry out real-time analysis of large scale SNN with minimal cost as large amount of complex data needs to be processed and displayed at the same time. This work intends to provide an efficient cost effective and power efficient emulation tool based on hardware-software hybrid to process, control, and display large-scale SNN network behavior in real time. The solution consists of a customized hardware architecture that computes the neural-synaptic parameters and a software environment that displays the same on the screen of a general purpose computer (Host). The data to be visualized is transferred to the host through high speed Ethernet link. The proposed solution tailors the use of the Ethernet link bandwidth to an optimum such that the customized neuromorphic architecture and the host computer duo can be used to visualize the dynamics of SNN network of any size in real-time. The hardware and software platforms are scalable in terms of number of neurons and synapses. This solution gives flexibility to the user to visualize and analyze SNN network of any size avoiding saturation of the high-speed serial Ethernet link while supporting the visualization of SNN dynamics with a good screen resolution.

A Completion Time-Based Flow Scheduling for Inter-Data Center Traffic Optimization

With the rise of cloud computing service, traffic in inter-data center wide area networks (inter-DC WANs) has been growing rapidly. Inter-data center traffic contains multitudinous data transfers that require to be accomplished within certain time periods or deadlines. The different completion time of the transfer tasks has distinct impacts on the performance of the whole system. However, very little work takes the completion time into account while guarantees the hard deadlines. Besides, most previous works arrange transfers exclusively, which does not take fairness into account. In this paper, we introduce a completion time-based model, which takes multiple deadlines and their impacts into consideration to profile a more accurate characterization of the data transfers. We propose a novel mechanism to achieve the goals of both maximizing utility and fairness. We also develop an inter-DC WAN emulation tool which enables a single commodity server to emulate arbitrary topology and dynamic configuration on the WAN links. Our evaluation demonstrates that our algorithm gains 110%–250% utility than current deadline focus mechanisms, while achieves 12% higher throughput. Fairness is improved over four times at best by adjusting the fairness coefficient.

Improving Weather Forecast Skill through Reduced-Precision Data Assimilation

Abstract A new approach for improving the accuracy of data assimilation, by trading numerical precision for ensemble size, is introduced. Data assimilation is inherently uncertain because of the use of noisy observations and imperfect models. Thus, the larger rounding errors incurred from reducing precision may be within the tolerance of the system. Lower-precision arithmetic is cheaper, and so by reducing precision in ensemble data assimilation, computational resources can be redistributed toward, for example, a larger ensemble size. Because larger ensembles provide a better estimate of the underlying distribution and are less reliant on covariance inflation and localization, lowering precision could actually permit an improvement in the accuracy of weather forecasts. Here, this idea is tested on an ensemble data assimilation system comprising the Lorenz ’96 toy atmospheric model and the ensemble square root filter. The system is run at double-, single-, and half-precision (the latter using an emulation tool), and the performance of each precision is measured through mean error statistics and rank histograms. The sensitivity of these results to the observation error and the length of the observation window are addressed. Then, by reinvesting the saved computational resources from reducing precision into the ensemble size, assimilation error can be reduced for (hypothetically) no extra cost. This results in increased forecasting skill, with respect to double-precision assimilation.

RapidIO as a multi-purpose interconnect

RapidIO (http://rapidio.org/) technology is a packet-switched high-performance fabric, which has been under active development since 1997. Originally meant to be a front side bus, it developed into a system level interconnect which is today used in all 4G/LTE base stations world wide. RapidIO is often used in embedded systems that require high reliability, low latency and scalability in a heterogeneous environment - features that are highly interesting for several use cases, such as data analytics and data acquisition (DAQ) networks. We will present the results of evaluating RapidIO in a data analytics environment, from setup to benchmark. Specifically, we will share the experience of running ROOT and Hadoop on top of RapidIO. To demonstrate the multi-purpose characteristics of RapidIO, we will also present the results of investigating RapidIO as a technology for high-speed DAQ networks using a generic multi-protocol event-building emulation tool. In addition we will present lessons learned from implementing native ports of CERN applications to RapidIO.

Exploring RapidIO Technology Within a DAQ System Event Building Network

RapidIO ( http://rapidio.org/ ) technology is a packet-switched high-performance fabric, which has been under active development since 1997. The technology is used in all 4G/LTE base stations worldwide. RapidIO is also used in embedded systems that require high reliability, low latency, and deterministic operations in a heterogeneous environment. RapidIO has several offloading features in hardware, therefore relieving the CPUs from time- and power-consuming work. Most importantly, it allows for remote direct memory access and thus zero-copy data transfer. In addition, it lends itself readily to integration with field-programmable gate arrays. In this paper, we investigate RapidIO as a technology for high-speed data acquisition (DAQ) networks, in particular the DAQ system of an LHC experiment. We present measurements using a generic multiprotocol event-building emulation tool that was developed for the LHCb experiment. Event building using a local area network, such as the one foreseen for the future LHCb DAQ, puts heavy requirements on the underlying network as all data sources from the collider will want to send to the same destinations at the same time. This may lead to an instantaneous overcommitment of the output buffers of the switches. We will present results from implementing an event building cluster based on RapidIO interconnect, focusing on the bandwidth capabilities of the technology as well as its scalability.

A Review Paper on Software Defined Networking

The comprehensive concept of SDN(Software Defined Networking) has introduced the extensive change to the traditional networks with the integration of the network by decoupling the forwarding hardware (data plane) from the control logic of the network (control plane).Software Defined Networking (SDN) is a new way of technology that is helping to overcome the limitations of traditional networks. With the help of this emerging technology paradigm has created a great future, an expectation to overcome the need for reliable, secure, flexible and well management of next generation networks. The basic idea behind it is the separation of control plane from data plane. SDN has made the Networks more programmable. SDN is a three layered architecture. OpenFlow Protocol is the most common protocol used for providing the interface called as Southbound APIs between control layer and physical layer. On the other hand interface provided in between application layer and control layer is called as Northbound APIs. All the intelligence is lying in control layer. Controller acts as a brain of the network which is configuring and managing the flow of network through network devices present in physical layer. This paper illustrates the introduction about Traditional networks, Software Defined Networking its architecture, interfaces popular controllers, mininet emulation tool used in SDN, its topologies and security threats in SDN. Keywords: Software Defined Networking, Data plane, Control plane, Network Function Virtualization, Open Network Foundation, Type-Length-Value

Subjective MOS model and simplified E-model enhancement for Skype associated with packet loss effects: a case using conversation-like tests with Thai users

This paper proposes two mathematical models that can be used to estimate VoIP quality from Skype, which is one of the most popular VoIP applications. The first model is simple, it has been developed using data from the informal interview tests called Conversation-like tests, referring to packet loss of 0 %, 5 %, 10 %, …, and 30 %. The tests have been conducted with Skype using a non ITU-T’s codec called SILK via the Internet with over 180 native Thai participants, while packet loss effects were generated using a network emulation tool. The second model is called the Enhanced Simplified E-model, this has been developed by adding the Thai Bias factor into a generic Simplified E-model, which calculates by subtracting the subjective results from the computed results using the Simplified E-model formula. After obtaining the models, they were evaluated with the Test set from 36 native Thai participants (different from the other group of participants) using Mean Absolute Percentage Error technique (MAPE). It has been found that VoIP quality measurement performance of both models are classified as excellent and provide higher reliability and accuracy than the Simplified E-model. Subjective MOS model and Enhanced Simplified E-model error reduction compared to the simplified one was at about 21.9 % and 21.2 % respectively, which is the major contribution of this work.

The Extended Dijkstra’s-based Load Balancing for OpenFlow Network

<span lang="EN-US">This paper proposes load-balancing algorithm on the basis of the Extended Dijkstra’s shortest path algorithm for Software Defined Networking (SDN). The Extended Dijkstra’s algorithm considers not only the edge weights, but also the node weights to find the nearest server for a requesting client. The proposed algorithm also considers the link load in order to avoid congestion. We use Pyretic to implement the proposed algorithm and compare it with related ones under the Abilene network topology with the Mininet emulation tool. As shown by the comparisons, the proposed algorithm outperforms the others in term of the network end-to-end latency, throughput and response time at the expense of a little heavier computation load and more memory usage on the SDN controller.</span>

Modeling memory effects in RF power amplifiers applied to a digital pre-distortion algorithm and emulated on a DSP-FPGA board

An emulation tool with the capability of modeling the nonlinearity order and memory effects for real power amplifier’s (PAs) conversion curves, is introduced. The proposed tool comprises special cases of Volterra series as the Memory Polynomial Model and a learning technique like artificial neural networks. The proposed system is a novel integrated one able to model the real behavior of radio frequency (RF)-PAs under different memory models. The developed system starts from a test bed able to acquire AM–AM and AM–PM distortion curves measurements. This procedure can predict the behavior and improve the analysis using it as a design tool.

Design and Testing of Custom FPAA Hardware With Improved Scalability for Emulation of Smart Grids

In this paper, the authors present work in the field of analog emulation of electric power system dynamics via field-programmable analog array (FPAA) technology. Specifically, they discuss development of a new emulation tool with increased modularity and operator density for analysis of larger power systems and smart grids. One innovative aspect of this work is the fact that it employs custom FPAA boards developed by researchers at The College of New Jersey and Drexel University. The work places emphasis on decreased prototype size, increased density of computational analog blocks (CABs), more effective FPAA interconnection scheme, and batch-mode FPAA configuration.

Investigating a Hypothetical Semiconductor Laser Bar with a Damaged Single Emitter Using a Laser Diode Simulation/Emulation Tool

This study demonstrates the use of Barlase, a semiconductor laser diode emulation tool, to emulate the by-emitter degradation of high power semiconductor laser diodes. Barlase is software that uses a LabView control interface. In this study, a hypothetical laser diode bar (multiple emitters) was used to investigate a damaged single emitter randomly located in the bar and its behavior analyzed within the bar. It should however, be noted that, this scenario is valid for devices at the start of the aging process only. When all other relevant effects that affect the performance of laser diodes bars are allowed to interact over time, high levels of defects can also play important role in the degradation process. The results of this simulation scenario show the successful implementation of Barlase in the by-emitter analysis of laser diodes.

Investigating a Hypothetical Semiconductor Laser Bar Using a Laser Diode Simulation/Emulation Tool Using Random Levels of Defects

In this study, <em>Barlase</em>, a semiconductor laser diode emulation tool, is used to emulate the by-emitter degradation of high power semiconductor laser diodes. <em>Barlase</em> is a software that uses a LabView control interface. We have demonstrated how Barlase works using a hypothetical laser diode bar (multiple emitters) to validate the usefulness of the tool. A scenario using the hypothetical bar was investigated to demonstrate <em>Barlase</em> as follows: random low-level of defects distributed across the bar. The results of the simulation show the successful implementation of <em>Barlase</em> in the by-emitter analysis of laser diodes.