Software Switch Research Articles

Adaptive neural network based controller for direct torque control of PMSM with minimum torque ripples and EMI noise reduction

PurposeThe paper aims to provide an adaptive neural network controller for permanent magnet synchronous motor (PMSM) under direct torque control (DTC) algorithm to minimize the torque ripple and EMI noise.Design/methodology/approachThe design methodology is based on vector control used for electrical machines. MATLAB simulations supported with experimental study under C++ are used.FindingsThe simulated and experimental results show that considerable torque ripple as well as current ripple and EMI noise reduction can be achieved by utilizing adaptive neural switching algorithm to fire the inverter supplying the PMSM.Research limitations/implicationsThis research is limited to PMSM, however the research can be extended to include other AC motors as well. In addition, the following points can be studied: the effects of harmonics in control signals on the torque ripple can be analyzed; the actual mathematical relation between the torque and flux ripple can be studied to set the flux and torque bands width in reasonable value; different neural network algorithms can be applied to the system to solve the similar problems.Practical implicationsBased on existing DTC control system, it is only required to change the software switching algorithm, to provide smooth torque, given that the switching frequency of the inverter module is more than or equal to 15 MHz and the system is supplied with timers. In addition a relatively higher DC voltage may be required to achieve higher speed compared with the traditional DTC.Originality/valueIn this paper, the stator flux position, and errors due to deviations from reference values of the torque and stator flux are used to select two active vectors while at the same time the absolute value of the torque error and the stator flux position are used neural network structure to adapt the switching of the inverter in order to control the applied average voltage level in such a way as to minimize the torque ripple, so instead of fixed time table structure, a neural network controller is used to calculate the switching time for the selected vectors and no PI controller is used as the case in the traditional space vector modulation. This work is directed to motor drive system designers who seek highly smooth torque performance with EMI noise reduction.

The software switch for transmission systems with different protocols

The software switch for transmission systems with different protocols

Permanent magnet synchronous motors

PurposeThis paper aims to apply a two‐axis model for accurate representation of the characteristics of permanent magnet synchronous motors (PMSM) of the interior type.Design/methodology/approachFor a three‐phase PMSM, it uses a voltage source inverter with six power transistors with independent switching and PSIM software with Matlab for checking, by simulation, how some parameters influence the start process.FindingsIt was found that pulsating components generate the synchronizing torque.Originality/valueThe paper provides a model for accurate representation of the characteristics of permanent magnet motors.

TCP/IP를 이용한 하드웨어 전환장치 설계에 관한 연구

The SSWM(Software Switching Mechanism) of I-processor concept using non-real time in-house software simulation program is an effective method in order to develop the flight control law in desktop or HQS environment. And, this system has some advantages compare to HSWM(Hardware Switching Mechanism) such as remove the time delay effectiveness and reduce the costs of development. But, if this system loading to the OFP(Operational Flight Program), the OFP guarantee the enough throughput in order to calculate the two control law at once. Therefore, the HSWM(Hardware Switching Mechanism) of 2-processor concept is necessary. This paper addresses the concept of HSWM of the HQS-PC interface using TCP/IP(Transmission Control Protocol/Internet Protocol) communication based on flight control law of advanced supersonic trainer. And, the fader logic of TFS(Transient Free Switch) and stand-by mode of reset '0' type are designed in order to reduce the abrupt transient response and minimize the integrator effect in pitch axis. The result of the analysis based on HQS pilot simulation using HSWM reveals that the flight control systems are switching between two computers without any problem.

Radware CEO says networks must be immunized high up the stack

Roy Zisapel, co-founder of Radware, has served as its president and chief executive officer and a director since inception. Radware sells application switching hardware and software that manage network traffic. From February 1996 to March 1997, Zisapel was a team leader of research and development projects for RND Networks. He has a B.Sc. degree in mathematics and computer science from Tel-Aviv University. Brian McKenna spoke to him at the end of 2006 for Infosecurity magazine about how he sees the network security market.

DORIS satellite phase center determination and consequences on the derived scale of the Terrestrial Reference Frame

We analyzed 1 year of DORIS data to estimate daily corrections to the mean locations of the satellite antenna phase centers. For each DORIS satellite, we looked for possible biases, discontinuities, trends or annual signals. All SPOT satellites show very similar patterns, which are characterized by a significant constant bias of about 20 mm in the cross-track direction as well as a clear annual signal of 5 mm amplitude. All DORIS satellites show a consistent systematic radial offset of 10–20 mm (equivalent to 1.5–3.0 ppb in the Terrestrial Reference Frame) when using ITRF2000 and less than 1 ppb using ITRF2005P. A discontinuity unexpectedly appears in DORIS radial antenna phase center offset of the ENVISAT satellite on October 12, 2004, at the time of a flight software switch. GPS phase center offsets were also computed for Jason and TOPEX/Poseidon and no significant differences were found between DORIS and GPS estimations. Finally, we applied these estimated DORIS satellite antenna phase center offsets to derive weekly time series of station coordinates in 2004. Results showed very small improvement for station coordinates and confirmed that DORIS scale could match ITRF2000 scale by modifying the vector between the center of mass of the satellite and the phase center of the on-board antenna with a proper radial offset. At this point, we do not recommend the adoption of any empirical DORIS satellite phase center offsets at this point.

제어법칙 개발을 위한 소프트웨어 전환장치 설계에 관한 연구

Relaxed Static Stability(RSS) concept has been applied to improve aerodynamic performance of modern version supersonic jet fighter aircraft. Therefore, the flight control systems are necessary to stabilizes the unstable aircraft and provides adequate handling qualities. The initial production flight control system are verified by flight test and it's always an elements of danger because of flight-critical nature of control law function and design error due to model base design method. These critical issues impact to flight safety, and it could be lead to a loss of aircraft and pilot's life. Therefore, development of an easily modifiable RFCS(Research Flight Control System) capable of reverting to a PFCS(Primary Flight Control System) of reliable control law must be developed to guarantee the flight safety. This paper addresses the concept of SSWM(Software Switching Mechanism) using the fader logic such as TFS(Transient Free Switch) based on T-50 flight control law. The result of the analysis based on non-real time simulation in-house software using SSWM reveals that the flight control system are switching between two computers without any problem.

Switch Software Improves Reliability of Physiological Network, Patient Safety

Switch Software Improves Reliability of Physiological Network, Patient Safety

A VoIP communication system for advanced public networks

AbstractWith recent advances in IP‐related technology, VoIP, which can provide cheaper communications than conventional telephone networks, is attracting interest. Communication within IP networks has already been established in practice. In the early stage of introduction of the technology into the public network, VoIP and conventional tele‐phony coexist, and it is important in spreading the use of VoIP that interconnection to the existing network should be achieved. Furthermore, in order to promote the shift from telephone to VoIP, the existing telephone service should be available. These functions of interconnection and the existing service are resources of the PSTN exchange system, and it is inefficient if a new VoIP system is developed without utilizing these resources. Consequently, this paper proposes an architecture for the Call Agent system in which the above functions and the VoIP function are achieved by extending the PSTN switching software. © 2005 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 89(4): 52–60, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10229

Analyzing the Evolution of Large‐Scale Software

Journal of Software Maintenance and Evolution: Research and PracticeVolume 16, Issue 6 p. 363-365 Issue OverviewFree Access Analyzing the Evolution of Large-Scale Software Tom Mens, Tom MensSearch for more papers by this authorJuan F. Ramil, Juan F. RamilSearch for more papers by this authorMichael W. Godfrey, Michael W. GodfreySearch for more papers by this author Tom Mens, Tom MensSearch for more papers by this authorJuan F. Ramil, Juan F. RamilSearch for more papers by this authorMichael W. Godfrey, Michael W. GodfreySearch for more papers by this author First published: 18 November 2004 https://doi.org/10.1002/smr.300Citations: 8AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume16, Issue6Special Issue: Analyzing the Evolution of Large‐Scale SoftwareNovember/December 2004Pages 363-365 RelatedInformation

Switching remote robot manipulation in Internet TeleCare systems

In this paper, a Java and common object request broker architecture (CORBA) based management server is presented to switch the robot manipulating rights among the authorized caregivers in Internet TeleCare systems. A software switch, chat room and me

Maintaining telephone switching software requirements

We discuss how telephony software requirements should be structured to reduce maintenance costs. "Feature interaction" problems have become a serious obstacle to add more features to telephone switches. We show why existing public switched telephone networks are hard to modify. We then argue that a more modular, layered requirements architecture can help. Finally, we survey approaches for such an improved telephone switching architecture and discuss them.

Statistical modeling applied to managing global 5ESS®-2000 switch software development

In the development of new releases of large software systems, the software is evaluated by various development and testing organizations. To ensure that software faults causing customer-affecting failures are minimized at each stage of the development cycle, we use developer-oriented and customer-oriented metrics to measure software quality. Developer-oriented metrics focus on faults and fault densities during testing to monitor development process capabilities and software quality. These metrics are expressed as the number of faults per thousand of non-commentary source lines of code (KNCSL). Customer-oriented metrics focus on failure intensity during software execution, thus providing a user's view of the software quality. These metrics are expressed as the number of failures per unit of time. This paper describes the use of empirical software tracking models and software reliability models, as well as reports derived from these models, in managing the 5ESS®-2000 switch development resources and product quality.

An empirical study of software faults preventable at a personal level in a very large software development environment

The Capability Maturity Model of the Software Engineering Institute (described by Watts S. Humphrey in Managing the Software Process, by Addison-Wesley, 1989) defines software fault prevention as a key process area required at Level 5 — the “optimizing” level. We conducted a detailed study on a number of software faults found during low-level design, coding, and unit testing in the 5ESS®-2000 switch software development environment. We discovered that the faults found during those phases were typically limited in their scopes of impact, but they usually account for more than 60% of the total software faults found in a software product before its delivery. We also found that the corrective and preventive tasks of each fault identified during those phases were very likely manageable by one development engineer. The results of the study of frequent software faults served as a base of knowledge that enabled engineers to strengthen their design and programming capabilities and prevent faults from occurring again.

Efficient routing for IP subnet VLAN over Ethernet

AbstractExisting IP routing algorithms have been developed mainly for non‐VLAN networks. For these routing algorithms to work, an end station must be attached to its associated network. The introduction of VLAN has, however, allowed the physical location of the end station to be changed from time to time. Therefore, some extra mechanism is required to support routing in VLAN environment. Existing approaches have some drawbacks in terms of inefficiency in traffic forwarding and switch software complexity. In this paper, a simple and efficient method for routing over IP subnet VLAN in Ethernet is proposed. This method has been implemented in hardware and found to work correctly. Various measurements and analyses have been performed to verify the efficiency of this protocol. Copyright © 2002 John Wiley & Sons, Ltd.

Advanced services architectures for Internet telephony: a critical overview

Advanced services are differentiating factors and crucial to service providers' survival and success. Examples are credit card calling, call forwarding, and toll-free calling. In classical telephony's early days their implementation was embedded in switching software, and this hindered fast deployment. A more modern architecture known as the intelligent network (IN) was born in the 1980s, allowing implementation in separate nodes, resulting in faster deployment of new services. Two tracks are emerging for Internet telephony: one from the ITU-T and the other from the IETF. As far as advanced services are concerned, the ITU-T track offers a rather archaic architecture, reminiscent of the early days of classical telephony. On the other hand, the IETF architecture, although more modern, does have a few pitfalls. There is plenty of room for improvement to both. This article scrutinizes the ITU-T and IETF advanced services architectures for Internet telephony. Salient features are reviewed and weaknesses pinpointed. Although these architectures are constantly evolving, alternatives may emerge. We provide a discussion of two potential alternatives: IN-based architectures and mobile-agent-based architectures.

IBM 8265 ATM Backbone Switch software architecture

The IBM 8265 ATM Backbone Switch is the latest switch in the family of IBM ATM switches, designed for building large scale and reliable ATM network backbones. Two articles on the IBM 8265 ATM Backbone Switch are provided in this journal, describing the hardware architecture and the software architecture separately. This article describes the functions of the ATM Operating System and the ATM Multi-protocol Switched Services that run inside the IBM 8265 ATM switch. The focus is given to issues that are not addressed by the ATM Forum, and extensions that are needed when building ATM networks.

Information and communication systems for the assistance of carers based on ACTION.

Recent advances in telecommunication technologies allow the design of information and communication systems for people who are caring for others in the home as family members or as professionals in the health or community centres. The present paper analyses and classifies the information flow and maps it to an information life cycle, which governs the design of the deployed hardware, software and the data-structure. This is based on the initial findings of ACTION (assisting carers using telematics interventions to meet older persons' needs) a European Union funded project. The proposed information architecture discusses different designs such as centralized or decentralized Web and Client server solutions. A user interface is developed reflecting the special requirements of the targeted user group, which influences the functionality and design of the software, data architecture and the integrated communication system using video-conferencing. ACTION has engineered a system using plain Web technology based on HTML, extended with JavaScript and ActiveX and a software switch enabling the integration of different types of videoconferencing and other applications providing manufacturer independence.

A graph theoretical method for the management and synchronization of large software updates

Up to 1992, the international 5ESS telephone switch software update system, which maintains and updates released products software, was able to process the load of software update packages consistent with customers' needs. In May 1992, the introduction of a new international release, coupled with increased diversity of customer needs, amplified the complexity inherent to the management of large software projects, thus significantly increasing the demand on the software update delivery system. The usual result of such a situation is an increase in the package queue length and time. To bring the throughput to the required level, a solution was developed based on a theoretical model where two levels of abstraction of directed and undirected graphs were applied to represent the software update system. Using this graph model, a new tool was rapidly developed for the analysis and production of software update packages. Two weeks after the tool was released and over a period of three months, queue time for software update packages processing declined from 40 days to a steady state of 2–3 days. Key to the development of the technique was the intimate knowledge of the software development and update processes by a team of developers who supported the implementation of the technique. © 1998 John Wiley & Sons, Ltd.

Model checking without a model

VeriSoft is a tool for systematically exploring the state spaces of systems composed of several concurrent processes executing arbitrary code written in full-fledged programming languages such as C or C++. The state space of a concurrent system is a directed graph that represents the combined behavior of all concurrent components in the system. By exploring its state space, VeriSoft can automatically detect coordination problems between the processes of a concurrent system.We report in this paper our analysis with VeriSoft of the "Heart-Beat Monitor" (HBM), a telephone switching application developed at Lucent Technologies. The HBM of a telephone switch determines the status of different elements connected to the switch by measuring propagation delays of messages transmitted via these elements. This information plays an important role in the routing of data in the switch, and can significantly impact switch performance.We discuss the steps of our analysis of the HBM using VeriSoft. Because no modeling of the HBM code is necessary with this tool, the total elapsed time before being able to run the first tests was on the order of a few hours, instead of several days or weeks that would have been needed for the (error-prone) modeling phase required with traditional model checkers or theorem provers.We then present the results of our analysis. Since VeriSoft automatically generates, executes and evaluates thousands of tests per minute and has complete control over nondeterminism, our analysis revealed HBM behavior that is virtually impossible to detect or test in a traditional lab-testing environment. Specifically, we discovered flaws in the existing documentation on this application and unexpected behaviors in the software itself. These results are being used as the basis for the redesign of the HBM software in the next commercial release of the switching software.