Digital Switching System Research Articles

Design and Construction of a Multipole Electric Motor Using an Axial Flux Configuration

In the transportation industry, the use of renewable energies has been implemented in conjunction with the development of higher-power electric motors and, consequently, the development of intelligent control systems for torque and speed control. Currently, the coupling between both systems is being developed through mechanical systems, affecting the efficient transmission of energy and the useful life of the components. On the other hand, new configurations of electric motors are being developed, such as axial flux motors (AFM), because these can be coupled directly without a mechanical coupling, given their characteristics of high torque at low speeds. In the present work, an innovative design of a multipole axial flux motor (MAFM) is introduced. General criteria for the design and construction are presented considering the geometry in axial flux and permanent magnets. The performance of the system is evaluated through finite element magnetic simulations (FEMM) and compared with experimental measurements of the developed prototype; confirming the effectiveness of the design, obtaining torques of up to 1.784 Nm without extra mechanical couplings and maximum speed regulation errors of 8.43%. The motor was controlled by a digital pole switching system whit six control mode, applied to a permanent magnet MFA for speed and torque control at constant speed. This control can be extended to conventional radial flux electric motor configurations and intelligent traction applications, based on torque demand.

Teknologi Switching Digital Dan Non Digital

In this globalized world, where boundaries are breaking down, effective communication is not just a necessity but a must. It is the lifeblood of every organization, driving its operations and ensuring its growth. However, to achieve this, we need to have a strong system in place. The objectives of this study are to analyze the comparison of the performance of digital and non-digital switching systems, to compare the energy efficiency between digital and non-digital switching technologies in various operational conditions and to determine the simulation of digital and non-digital switching technologies. The method used in this research is a literature review or systematic review by collecting several research journals as reference material.

Управляемость одной вырожденной гибридной системы

We consider the linear hybrid system with constant coefficients that is not resolved with respect to the derivative of the continuous component of the unknown function. In Russian literature such systems are also called discrete-continuous. Hybrid systems usually appear as mathematical models of a various technical processes. For example, they describe digital control and switching systems, heating and cooling systems, the functioning of a automobile transmissions, dynamical systems with collisions or Coulomb friction, and many others. There are many papers devoted to the qualitative theory of such systems, but most of them deal with nonsingular cases in various directions. The analysis of the note is essentially based on the methodology for studying singular systems of ordinary differential equations and is carried out under the assumptions of the existence of an equivalent structural form. This structural form is equivalent to the nominal system in the sense of solutions, and the operator which transformes the investigated system into the structural form possesses the left inverse operator. The finding of the structural form is constructive and do not use a change of variables. In addition the problem of consistency of the initial data is solved automatically. Necessary and sufficient conditions for R–controllability (controllability in the reachable set) of the hybrid systems are obtained.

Triple‐mode bandpass filter

triple‐mode bandpass filter

Microwave Oscillator Based on a Single Straintronic Magnetotunneling Junction

There is growing interest in exploring nanomagnetic devices as potential replacements for electronic devices (e.g. transistors) in digital switching circuits and systems. A special class of nanomagnetic devices are switched with electrically generated mechanical strain leading to electrical control of magnetism. Straintronic magneto-tunneling junctions (s-MTJ) belong to this category. Their soft layers are composed of two-phase multiferroics comprising a magnetostrictive layer elastically coupled to a piezoelectric layer. Here, we show that a single straintronic magneto-tunneling junction with a passive resistor can act as a microwave oscillator whose traditional implementation would have required microwave operational amplifiers, capacitors and resistors. This reduces device footprint and cost, while improving device reliability. This is an analog application of magnetic devices where magnetic interactions (interaction between the shape anisotropy, strain anisotropy, dipolar coupling field and spin transfer torque in the soft layer of the s-MTJ) are exploited to implement an oscillator with reduced footprint.

Research on Design of Program - Controlled Switches

In the 1990s, the development of program-controlled switches in our country has experienced the development process from thescratch; especially the successful development of large-scale program-controlled switches has brought great vitality to our informationindustry. This time, I mainly introduced to ZTE ZXJ10 program-controlled switchboard to design distributed modularization in programcontrolledswitch. ZXJ10 digital program-controlled switching system is distributed between modules, module classification control,centralized management of the open architecture, based on general computer platform, LAN technology as the support, client/server modeto control the basic form of structure, in order to make the system has flexible networking ability, strong call processing capability, highreliability, good compatibility and expansibility.

Electrochemical Separation of Alanine, Cysteine, and Glycine Using a Digital Thruster

The present work deals with the use of a digital thruster for the electrochemical separation of amino acids. A digital thruster (DT) is a micro controller based digital electronic switching system (DT-MCDESS). Mixtures of amino acids were injected into the free electrolytic diffusion apparatus (FEDA). Micro cathodes surrounding a central anode were covered with agarose coated filter paper strips and programmed with DT-MCDESS. The charge was distributed over micro cathodes at time intervals of 100 and 200 µs, which result in deposition and separation of alanine, cysteine, and glycine filter paper strips. For identification of each amino acid, ninhydrin was sprayed to develop separate colors for deposited amino acids on filter paper strips. Alanine displayed as purple, cysteine as red, and glycine as yellow. The separation of alanine, cysteine, and glycine was performed at two frequencies, 312.5 Hertz and 625 Hertz.

The power of “a visible hand” to the building of innovation capabilities

Purpose – This paper aims to provide an analytical account of the process by which China has developed its complex and infrastructural information and communication technology (ICT) systems over the last three decades, with the result that today it has become a key player in the global ICT sector. This paper discusses the role of the Chinese government in supporting and coordinating large-scale ICT system deployments and implementation, by-passing dilemmas that have beset more laissez-faire economies. Design/methodology/approach – This paper is based on two case studies in China: public digital switching systems in the 1990s and 3G mobile standards recently. The former is a typical complex system and the latter exemplifies infrastructural technology. From the tradition of science and technology studies, it incorporates historical approach into a socio-technical discourse of the process and examines the operational practices of the Chinese government in different stages. Findings – The paper demonstrates the pivotal role of government in the case of a latecomer country like China in developing and implementing complex and infrastructural ICT systems. While development of such socio-technical systems has presented challenges in many countries, the findings show the transition of socio-technical context in China has provided the best operational platform for the government to perform its roles. Originality/value – Most research into innovation capabilities focuses on technological matters, while this paper also addresses the social context, institutional mechanisms and roles for coordinating different resources and players involved. In this way, it raises questions for conventional thinking in the West that market systems can perform the best in innovation.

Digital switching systems based on lateral self-oxidation of aluminum nanofilm processors

Advanced “smart label” systems incorporating digital functions and low temperature dependence were constructed from integrated time-dependent electrochemical switches based on the lateral self-oxidation of nanoscale aluminum films. The processors are capable of controlling an integrated display without need of external power and may be used for low-cost “self-writing smart labels” such as time indicators.

Silicon Photonic Interconnects for Large-Scale Computer Systems

Optical interconnects play an integral role in large-scale digital computing, switching, and routing systems. The authors describe a path toward future many-chip modules based on silicon photonic interposers that stitch together tens of chips in a dense and efficient communication infrastructure. They review the guiding design principles for this macrochip and describe its canonical energy, loss, and area budgets.

Achieving interoperability in synchronous digital hierarchy network management through RM-ODP

Ever since the introduction of computerized digital switching systems and related management systems, network operators have been struggling with the question of how to circumvent the issues of customized and proprietary network management solutions. This topic became of paramount importance to network equipment manufacturers and telecommunications service providers with the advent of the SDH and TMN standards in the late 1980s and early 1990s. It is in the context of this problem that the authors and their colleagues, as telecom standards experts, discovered the Reference Model for Open Distributed Processing (RM-ODP). This paper describes the approach taken by the authors and their colleagues to use RM-ODP to these issues in the ITU-T study groups, how those efforts were applied and the relevance of RM-ODP to current computing systems based on the concepts of Cloud Computing. This paper thus describes “real-world” business needs that have been addressed by and illustrate the benefits of RM-ODP.

Dr. Hiroshi Inose's pioneering contributions to digital switching systems and his outstanding leadership in informatics

The idea of time slot interchange (TSI), the fundamental concept of implementing time switches in digital switching systems, was first conceived by Dr. Hiroshi Inose, then at the University of Tokyo, Japan, in 1957 while he was a visiting consultant at Bell Telephone Laboratories. The TSI collects each subscriber's pulse code modulation (PCM)-coded voice information to be stored into a small time interval (time slot), and then aligns multiple time slots on a common transmission bus to constitute a repetitive frame. The TSI enables any time slot to be interchanged with another time slot within a frame once the time slots in the frame are buffered in memories. Thus, TSI gives the time switch functionality equivalent to N-input by N-output space switch functionality. He built a prototype digital time-division multiplexing (TDM) electronic switching system called CAMPUS, which is based on the TSI principle, using a magnetostrictive delay line as a memory device. TSI received little attention until the end of the 1960s because memory devices were very costly. However, with the rapid advancement of semiconductor technologies in the 1970s, the TSI scheme became more widespread. TSI was first commercially deployed in 1976 as the time switch of AT&T's no. 4 ESS, the world's first stored-program control time-division switching system. Since then, TSI has been used in almost all digital central office switching systems and digital private branch exchanges (PBXs). Dr. Inose's contributions were not limited to research on such things as switching systems, PCM integrated communications, computer communications, and road traffic control systems; he was also actively involved in a number of Japanese governmental and international activities in the area of communications and information processing technologies. His final work was the establishment of the National Institute of Informatics (NII) in 2000, Japan's sole comprehensive academic institute in the field of informatics that seeks to advance integrated research and development activities in information-related fields.

Two-way master-slave double-chain networks: limitations imposed by linear master drift for second order PLLs as slave nodes

Distribution of precise time signals among the nodes of a network is a fundamental requirement for digital transmission and switching systems in telecommunication and control. Cideciyan et al., (1987) conjectured that two-way master-slave (TWMS) networks present, in the general case, a better performance than one-way master-slave (OWMS) considering the long term linear master frequency drift. In this work we study the TWMS case using dynamical system theory showing that, due to the effects of long-term clock instabilities, the steady-state frequency-error is unstable for a number of slaves higher or equal than four, limiting the use of this kind of architecture.

Learning from Technology Transfer in the Greek Context: The Case of Digital Telecommunication Switches

This paper examines the process of technology transfer and associated learning effects experienced by the Greek telecommunication equipment manufacturer INTRAKOM as a result of its involvement in public procurement processes and the technological shift towards software-driven digital switching and transmission systems. Drawing upon the role of Government procurement as an instrument for industrial policy and the learning potential of a technology transfer process, the paper argues that the Public sector's industrial policy considerations, exercised through the procurement practices of the Greek Public Telecommunication Operator (OTE), as well as INTRAKOM's own timely focus in establishing a long-term collaboration agreement with a leading international vendor (ERICSSON) played a catalytic role in the accumulation of domestic capabilities in the manufacturing of selected telecommunication equipment products.

Evolution of component-qualification methods for local component-manufacturers for telecom applications

The Centre for Development of Telematics, C-DOT, was set up in 1984 by the Indian Government to develop a new generation of digital switching systems relevant to the Indian environment. Consequently, CDOT developed a range of cost-effective products, predominantly relevant to the dispersed rural needs of India, with the built-in qualities of ruggedness, upgradability, and reliability so as to withstand the extreme environmental/climatic conditions prevailing in India. Standardization and vendor-quality monitoring were also undertaken for ensuring reliable component supplies for mass manufacturing C-DOT products. The effort by C-DOT, while using primarily components which are locally available in its products, through standardization, vendor development and vendor monitoring, was quite rewarding in achieving the basic objectives of C-DOT. This paper highlights: the chronological sequence of events in this mammoth effort; the pragmatic approach, and its relevance, in evolving the component-qualification methodology; and the importance of component quality, component vendor development, the quality and reliability efforts, qualification testing and strategy, and failure-analysis of components. The result of C-DOT effort in ensuring quality standards is seen in 19000 RAX (rural exchanges), over 300 MAX, and many wireless and satellite systems in operation throughout India, in inhospitable environment conditions.

Switching systems and switching software development in China

The architectures of two medium-sized digital telephone switching systems that were developed in China, the DS-30 and HJD-04 systems, are discussed. The DS-30 is a 30000 line digital telephone switching system, with a total capacity of 300000 busy hour call attempts (BHCA) using digital line concentration and a time-space-time switch fabric. Its architecture is a distributed control, multistage, multiprocessor system with load and function sharing. The HJD-04 is a 30000 line digital telephone switching system, with a total capacity of 2 million BHCA. The significant feature of the HJD-04 system is its switching network, which consists of a single time switch. The structure of the switching software support environment used in China is discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Modelling and Performance Analysis of a Digital Switching System—Case Study of the C-DoT DSS

It is now well recognised that modelling and performance analysis is an important and necessary part of the development cycle of any large telecommunication system. The authors demonstrate some of the techniques that are used, and the kinds of results that can be obtained, by describing a detailed performance analysis done for the Centre for Development of Telematics' Digital Switching System (C-DoT DSS). They used a simulation model to evaluate the performance of the Base Module (BM). This model yielded an estimate of BM capacity, helped to design and evaluate a new overload control, and showed how BM capacity can be improved by a scheduling change. They used analytical queuing models to estimate the capacities of the Administrative Processor, and the Space Switch Controller. They formulated the system overload control problem as a constrained optimisation problem, solved the problem, and used simulations to evaluate various adaptive overload control algorithms.

Traffic analysis of large TST networks

The traffic performance of time-space-time (TST) switching networks built from large time-switching stages used in digital switching systems is discussed. These switching networks exhibit steep load-service characteristics and present new numerical problems for traffic performance evaluation. The precise numerical calculation of switch blocking and the amount of search effort needed to find a network path are addressed. Computational efficiency and robustness are emphasized. The approach is based on a familiar model that uses state-dependent transitions in formulating the balance equations. A comparative study with traditional methods illustrates the numerical gains to be made for switching networks of arbitrary size. >

Oscillations and chaos in a flow model of a switching system

Field data from digital switching systems in an access tandem environment indicate unexpectedly large queuing delays at moderate occupancies. It is shown that these delays are caused by an effect called traffic synchronization, which is the batching of a system's workload caused by interactions between the system and incident traffic. The authors develop a flow model to study this effect and show that a momentary overload can cause sustained oscillations in the system's queues. There are several steady-state modes of operation, and it is shown that for certain parameter ranges the system is chaotic. Such oscillatory behavior can significantly lower the real-time capacity of the switching system, and controls to limit the synchronization effect are suggested. These controls are incorporated into the flow model and analyzed. The results described are validated by numerical studies, simulations, and field data. >

Overload control using rate control throttle: selecting token bank capacity for robustness to arrival rates

The design of rate-control throttles, which are used for overload control of computer and communication networks is discussed. An analysis of the rate-control throttle is presented. It is found that if the token bank capacity is 10 or more and if jobs arrive as a Poisson process, then for many practical applications in digital switching systems and telecommunication networks the control settings can be set independently of the arrival rate and need only be adjusted for changes in the desired departure rate. If the arrival of jobs is bursty (coefficient of variation of interarrival times is greater than 1), then the robustness declines but may remain quite good, depending on parameter values. The rate-control throttle with any token bank capacity is significantly more robust to arrival rates than either a percent-blocking throttle or a call-gapping throttle. >