Journal articles on the topic 'Telecommunication – Switching systems'

Modern high-speed telecommunication networks with time division multiplexing (TDM) based on nx64kBit/s channel switching cannot function without a high-quality network synchronization system, which is designed to ensure the reliability and stability of the formation, switching and processing of information in digital channels. The clock synchronization system is based on the transmission of the reference frequency from the primary clock to all digital equipment of the telecommunication network through the high-speed streams of transmission systems. However, in the case of distributed communication networks, the integrity of the clock synchronization system is violated, and there is a need to develop special technical solutions to ensure the provision of frequencies for all remote network elements. This article is devoted to an overview of such solutions.

Wavelength-division multiplexing (WDM) lightwave transmission systems and wavelength-division (WD) photonic switching systems are attractive for improvement in line capacity for lightwave telecommunication services, because they utilize a huge wavelength (frequency) domain as signal channels. Wavelength tunable optical filters are key devices for these WDM and WD systems in direct detection scheme. In particular, semiconductor wavelength tunable optical filters are suitable for monolithic integration with photonic devices such as semiconductor lasers, switches and detectors. Also, the switching speed of wavelength is faster than that of other optical filters. This paper briefly summarizes the state-of-the-art semiconductor wavelength tunable optical filters and their applications to WD photonic switching systems.

A model is developed that allows simulating the most-likely failures possibly occurring in freecooling (FC) systems of telecommunication (TLC) switching rooms. Main aim is to provide an effective and online implementable diagnosis method, which in turn will allow fulfilling the threefold function of safeguarding electronic equipment, ensuring desired air quality in case of human presence and reducing malfunction-related waste of energy. Specifically in this work, obstruction (reduction of the volumetric flow of air introduced into the room) and loss of efficiency (degradation of the fan) are deepened. Two black-box sub-models were developed to simulate the above described faulty functioning of the free-coolers. Subsequently, the fault signature matrix was developed, through which the “symptoms”, calculated as residuals between the “faulty” and “non faulty” conditions of the monitored variables, are associated to the corresponding faults. The peculiarity of the telecommunication sector, where nowadays data acquisition and monitoring platforms are significantly spreading to monitor most significant energy consumptions, including cooling loads, was proved essential in guaranteeing effective isolation of different faults. The simulation results highlight the reliability of the developed diagnostic tool, expected to be versatile and easy to implement enough for being extended to air-handling unit diagnosis, as well as other industrial sectors.

To analyze the performance of the PID controller in a buck type converter implemented in real time. We begin by designing a continuous controller using the analytical method for calculating PIDs. Pulse width modulation is then used and bifurcation diagrams analyzed to reveal some problems of switching and sampling time. The model converter is then implemented with a PID controller in dSPACE. The experimental results provide detailed requirements of sampling frequency and switching speed, and show the performance of the PID controller. Converters are used in power generation solar systems and conmuted power sources for feed telecommunication devices, smart grids, and other applications.

PurposeThe purpose of this paper is to derive the user‐perceived availability of M‐for‐N shared protection systems composed of multiple user groups, each with a protection‐switching priority.Design/methodology/approachThe paper assumes a shared protection system with M protection units and N working units. The memoryless state transition diagram viewed from the system administrator, combined with combinatorial analysis of state probabilities on protection switching, yields a generic formula of the availability viewed from an arbitrary end user.FindingsThe numerical examples of availability reveal the effect of prioritized protection switching. It is observed that the total protection capacity is constant regardless of the ways of priority grouping. The shared protection system with multiple protection units enables more flexible availability allocation compared with the case of a single protection unit.Research limitations/implicationsUser‐perceived reliability is still an unexplored research area. Many variations of the system treated in this paper can be applied to various applications.Practical implicationsThe analysis provides useful information for the design and operation of, for example, telecommunication network devices. The analysis is applicable to general shared protection systems that are subject to service level agreement (SLA) involving user‐perceived reliability measures.Originality/valueThis paper establishes the model of the priority shared protection systems for the first time and shows a practical computation method of prioritized user‐perceived availability.

Abstract In this paper the new 1×4 optical demultiplexer for next-generation all-optical switching systems is proposed. The controlled mirrors are the main elements of this device. The control voltage for this mirror is generated by a rectenna from an optical control signal. In according to operation principle this optical signal enters the system simultaneously with an information signal. The analytical approach of calculation energy losses in the demultiplexer based on the translation matrix method is proposed. And also the analytical method of performance calculation is offered for the first time. First of all, the delay time due the transient mode in the power supply circuit is found. The equivalent electrical scheme of the optical demultiplexer is proposed for the first time. Note that the theoretical results obtained in this work can be used for analysing various controlled optical devices. The numerical calculations in accordance to the presented methods are carried out also.

In future, the telecommunication systems will be totally based upon the photonic integrated circuits and components for the transmission of optical signals. Since optical signals offer high speed, less delay and higher efficiency. This introduces a new research area for photonic crystal based optical components like optical switch, multiplexer, optical filters etc. Among these devices, the optical switch draws more attention due to its primary switching operation. Hence, this paper deals with the modified design structure of GaAs photonic crystal based directional coupler all optical switch which operates at the wavelength of 1300nm. Further the switching performance evaluation of this device is made for both electro optic effect and non-linear optical effect. The design and simulation of the optical switch is done through Comsol Multiphysics software.

The paper describes the traffic flow problems in telecommunication networks based on the Internet protocol. The main aim of telecommunication network operator today is to offer an SLA (Service Level Agreement) contract to end users, with provided QoS (Quality of Service) for different classes of services. In order to achieve this, it is necessary to establish the routes between marginal network nodes meeting the network traffic requirements and optimizing the network performances free of simultaneous flows conflicts. In DiffServ/MPLS (Multi-Protocol Label Switching) networks traffic flows traverse the network simultaneously and there may come to collision of concurrent flows. They are distributed among LSPs (Labeled Switching Paths) related to service classes. In LSP creation the IGP (Interior Gateway Protocol) uses simple on-line routing algorithms based on the shortest path methodology. In highly loaded networks this becomes an insufficient technique. In this suggested approach LSP need not necessarily be the shortest path solution. It can be pre-computed much earlier, possibly during the SLA negotiation process. In that sense an effective algorithm for collision control is developed. It may find a longer but lightly loaded path, taking care of the collision possibility. It could be a very good solution for collision avoidance and for better load-balancing purpose where links are running close to capacity. The algorithm can be significantly improved through heuristic approach. Heuristic options are compared in test-examples and their application for collision control is explained. KEYWORDS: Telecommunication networks, collision avoidance, multi-constraint route selection, self-organizing systems, MPLS, QoS

The power management of ICT systems, that is, data processing (Dp) and telecommunication (Tlc) systems, is becoming a relevant problem in economical terms. Dp systems totalize millions of servers and associated subsystems (processors, monitors, storage devices, etc.) all over the world that need to be electrically powered. Dp systems are also used in the government of Tlc systems, which, besides requiring Dp electrical power, also requireTlc-specificpower, both formobilenetworks (with their cell-phone towers and associated subsystems: base stations, subscriber stations, switching nodes, etc.) and forwirednetworks (with their routers, gateways, switches, etc.). ICT research is thus expected to investigate into methods to reduce Dp- and Tlc-specific power consumption. However, saving power may turn into waste of performance, in other words, into waste of ICT quality of service (QoS). This paper investigates the Dp and Tlc power management policies that look at compromises between power saving and QoS.

This paper focuses on photogenerated carrier nonlinearities in InGaAs/InAlAs quantum wells (QWs) that use low optical power, display a relatively fast recovery time (280 ps down to 35 ps), and excellent optical properties in terms of the sharpness of the absorption edge. A guided-wave, all-optical switching device is demonstrated as an application, at a wavelength which is of interest to telecommunication systems (1.55 μm) and requires low control energy (<0.3 pJ/pulse). A key issue here is that the controlled introduction of defects in the QW heterostructures allows the time response to be fastened significantly without being detrimental to the performance of the device in terms of on-off contrast and switching energy. The preparation procedure is compatible with metalorganic-based growth techniques widespread in optoelectronics at 1.55 μm.

A technique of synthesis of a wireless digital communication network with package switching, providing transfer of video messages of real time scale between elements of multipurpose information-operating system in conditions of high failure rate of central elements, is considered. As conceptual model of a telecommunication network – the network of the mixed structure, including multipurpose devices, constructed on the basis of standards of a broadband radio access with switching of packages and two interconnected levels of network interaction of elements (local and main) is accepted. The technique of synthesis of a wireless network is based on the multilevel, combined adaptation of a telecommunication network in the conditions of refusals of central elements, which primary goal is rational change of parameters, functions of network elements in close interrelation with purposeful transformation of structure of telecommunication system subnetworks. The main objective of carrying out the combined adaptation of the network consists in achievement of necessary throughput of communication system depending on degree of failure rate of central elements. Properties of multilevel adaptation were investigated in the course of realization of the combined (structurally-parametrical) synthesis with use of the aggregate approach of modelling of difficult technical systems. Efficiency of the specified technique is proven by the results of the imitating experiment with use of the aggregate model of a wireless network of data transmission with switching of packages, obtained previously. The experimental data, received at natural research of networks of a broadband radio communication on the basis of standards 802.11 b/g/n, have shown, that time of processing of packages of a message essentially depends on use of existing ways of adaptation. In particular, application of effective algorithms of adaptation (both parametrical and structural) will allow to reduce the time of finding of details (packages) in broadband communication devices by several times and, thereby, to provide demanded throughput of the network functioning in the conditions of refusals of central elements.

Forward converters have been broadly used in the power supply industry due to their simplicity, worthy efficiency, and low cost. A novel prototype soft-switched zero-voltage and zero-current ZVZC PWM DC-DC power converter with low voltage/current stresses is introduced for telecommunication power feeding in this paper. A new two-switch interleaved forward converter circuit is introduced to minimalize current circulation with no supplementary auxiliary snubber circuits. This converter circuit includes some outstanding benefits such as reduced components, improved efficiency, high power density and economic circuit configurations for high power conditioning applications. The simple operation principle is demonstrated on the basis of steady-state analysis. Furthermore, the effective feasibility of the proposed circuit topology is evaluated and verified practically for a 500 W–100 kHz prototype breadboard. The operation principle and steady-state characteristics are demonstrated from a theoretical point of view. To verify the practical effectiveness of the proposed power converter, a 500 W–100 kHz prototype converter using ultrafast IGBTs is implemented for a distributed telecommunication energy plant. The studied soft-switching converter is evaluated in comparison with the previously-proposed PWM converters in terms of voltage, current stresses, and operating efficiency.

Abstract Nowadays, the development of optical telecommunication systems requires more efficient all-optical elements appreciation to their high data transmission speeds and reduced electromagnetic interferences. In this work, our objective is to attest by simulation a design of an optical switch using 2D photonic crystals from polystyrene, an organic polymeric material with high Kerr non-linearity. This excellent ultra-fast switching leads us to the exploited in the construction of two new structures of all-optical AND/NAND and OR/NOR logic gates. These structures based on non-linear ring resonator NRR of different radius in order to operate a telecom wavelength of 1550.3 µm using RSoft (Full-Wave) software. The average contrast intensity is between 15.52 and 23.42 dB and low delay time varied from 20 fs to 5.0 ps. Hence, resulting a very high output signal for ON-switching (82–130% of P in) and a weak signal for OFF-switching (0.2–7% of P in) through a minimum threshold power around of 1.2 mW/μm2.

While 3-D microelectromechanical systems (MEMS) allow switching between a large number of ports in optical telecommunication networks, the development of such systems often suffers from design, fabrication and packaging constraints due to the complex structures, the wafer bonding processes involved, and the tight alignment tolerances between different components. In this work, we present a 2-D translational MEMS platform capable of highly efficient planar optical switching through integration with silicon nitride (SiN) based optical waveguides. The discrete lateral displacement provided by simple parallel plate actuators on opposite sides of the central platform enables switching between different input and output waveguides. The proposed structure can displace the central platform by 3.37 µm in two directions at an actuation voltage of 65 V. Additionally, the parallel plate actuator designed for closing completely the 4.26 µm air gap between the fixed and moving waveguides operates at just 50 V. Eigenmode expansion analysis shows over 99% butt-coupling efficiency the between the SiN waveguides when the gap is closed. Also, 2.5 finite-difference time-domain analysis demonstrates zero cross talk between two parallel SiN waveguides across the length of the platform for a 3.5 µm separation between adjacent waveguides enabling multiple waveguide configuration onto the platform. Different MEMS designs were simulated using static structural analysis in ANSYS. These designs were fabricated with a custom process by AEPONYX Inc. (Montreal, QC, Canada) and through the PiezoMUMPs process of MEMSCAP (Durham, NC, USA).

In the last decade, silicon photonic switches are increasingly believed to be potential candidates for replacing the electrical switches in the applications of telecommunication networks, data center and high-throughput computing, due to their low power consumption (Picojoules per bit), large bandwidth (Terabits per second) and high-level integration (Square millimeters per port). This review paper focuses on the state of the art and our perspectives on silicon photonic switching technologies. It starts with a review of three types of fundamental switch engines, i.e., Mach-Zehnder interferometer, micro-ring resonator and micro-electro-mechanical-system actuated waveguide coupler. The working mechanisms are introduced and the key specifications such as insertion loss, crosstalk, switching time, footprint and power consumption are evaluated. Then it is followed by the discussion on the prototype of large-scale silicon photonic fabrics, which are based on the configuration of above-mentioned switch engines. In addition, the key technologies, such as topological architecture, passive components and optoelectronic packaging, to improve the overall performance are summarized. Finally, the critical challenges that might hamper the silicon photonic switching technologies transferring from proof-of-concept in lab to commercialization are also discussed.

The results of the analysis of the printed 8-beam antenna array with an operating frequency of 2.2 GHz are presented. Charting devices made on the basis of the Butler matrix are widely used in modern telecommunication and radar systems and complexes. Forming in space a fan of independent radiation patterns, such arrays provide both scanning in azimuth and elevation and switching several transmitters to different directions. This ensures a high efficiency of a multipath planar phased antenna array, and reduces its overall dimensions. To test the features of the implementation of the 8-input Butler matrix, an eight-beam dipole phased array antenna was modeled. The results of the system analysis and computer simulation showed that it is possible to print the antenna with acceptable performance.

Although the telecommunication industry in China is growing at a fast pace, and firms are making strong efforts to provide customers with various services, customer switching continues to be high. Satisfaction has been considered as one of the most important antecedent of customer loyalty. However, little attention has been paid to dissatisfaction, a qualitatively different construct from satisfaction, which also influences loyalty. Relying on the two-factor and three-factor theory, this research proposes a theoretical framework to demonstrate the coexistence of customer satisfaction and dissatisfaction, and investigates the different antecedents and influences of satisfaction and dissatisfaction on customer loyalty. Through an exploratory study, we derived 11 telecom service attributes and further classified them into three categories, namely, hygiene factors, bivalent factors, and motivating factors. Each of these categories has a distinct effect on shaping customers’ satisfaction and dissatisfaction. The PLS analysis of the survey data collected from 679 respondents provides insights into the complex interrelationships between 11 telecom service attributes, functional perception, motivating perception, customer satisfaction, customer dissatisfaction, and customer loyalty constructs. This study has a few interesting implications for researchers and telecom industry managers.

One of the important tasks of such theories as theories of pattern recognition and the theory of information security, is the task of identifying terminals of information and telecommunication networks. The relevance of the topic is due to the need to study methods for identifying computer network terminals and build information security systems based on the knowledge gained. The main parameters that allow uniquely identifying subscriber terminals in the network are address-switching information, as well as a number of parameters characterizing the software and hardware of the computer system. Based on the obtained parameters, digital fingerprints of subscriber terminals are generated. The using anonymous networks by users of subscriber terminals and blocking of the methods of generating and collecting digital fingerprint parameters, does not allow to achieve the required degree of identification reliability in some cases. Based on the peculiarities of digital image formation in modern computer systems, many transformation parameters make impact on the output graphic primitive, thereby forming a digital fingerprint of the subscriber terminal, which depends on the placement of samples in a pixel, the algorithms used to calculate the degree of pixels influence, and also the procedures used of smoothing images in the graphics subsystem. In this paper an original model of image formation by means of a subscriber terminal web browser that allows to increase the degree of reliability of identification under conditions of anonymization of users of information and telecommunication networks is propesed. Features of the digital images formation in the graphic subsystems of modern computer systems are substantiated. These features allow identification under a priori uncertainty regarding the modes and parameters of information transfer.

An analysis of the performance indicators multiservice telecommunication networks using the sixth technological order based on the NGN (Next Generation Network) architectural concept and future FN (Future Networks) networks was carried out to build high-performance steganographic systems with increased covert channels through-put, ensuring the achievement of a certain level information security. Comprehensive criteria for the efficiency the functioning steganographic systems are considered and the channel capacity of the steganosystem as a communication system with packet switching is selected. On the basis of the study, a new approach to constructing a method for evaluating complex indicators of the quality of steganographic communication during embedding and extracting hidden data is proposed. The quality of steganographic communication refers to the properties steganocommunication to ensure the efficiency of the system, both timely and reliable transmission of messages. On the basis of the proposed approach, the effectiveness steganographic systems in the construction of covert channels for the transmission secret data transmitted over communication channels was studied. Taking into account the new entropy approach, a method for calculating the indicators of the latent throughput steganographic systems in packet- switched communication networks has been created. As a result of the study calculation method, important analytical expressions were obtained for evaluating complex indicators throughput steganographic systems, such as the throughput of covert channels, the maximum possible value of the performance of a binary source packets, the average packet transmission time with the proposed coding scheme, and the residual throughput of the communication channel. Based on the results obtained, covert channel performance in steganographic systems was simulated using the Communications Toolbox package, an extension of the standard Matlab environment designed for calculating and modeling communication systems. The table contains indicators of the residual throughput of the system and the parameters of covert channel, taking into account the lengths of the headers of the network and channel levels of the open systems interaction models. With the considered method counteraction, a graphical dependence of the maximum value residual system throughput on the covert channel parameter is plotted. On the basis of the analysis, actual problems are identified, recommendations are developed to improve the efficiency of the use steganographic systems architectures for multiservice telecommunication networks.

Understanding of consumer experienced value in mobile services continues to be a strategic issue in the information systems literature. This is no different with Mobile TV that has become feasible with the convergence of telecommunication infrastructures, computer technology, and media content services. Mobile TV offerings are defined as real-time broadcast transmissions of content to mobile devices. We review mobile services literatures on consumer value creation and identify a gap in our understanding of how supplier firm's consumer-focused strategies may aid in consumption processes and thereby increase payments from consumers. We apply the perspective of consumer benefits experienced (CBE) to provide insight into how supplier firms may be able to increase consumer value. Value increases with greater consumer service-specific knowledge, and leveraging and complementing this knowledge across different offerings. Increased service-specific knowledge can also reduce demands on the consumer that can create important switching costs while increasing consumer-experienced value. This paper contributes to innovation research on mobile services.

This paper examines an MX/G/1 retrial model with negative customers including the concepts of working vacation, Bernoulli feedback, delayed repair, state-dependent and multi-optional services. Such a queue is quite relevant in real world, for instance in computer systems, manufacturing organisations, packet-switching networks, telecommunication systems, etc. The arrival pattern of customers is according to Poisson distribution. The service is such that first essential service (FES) is provided to every customer and second optional service (SOS) is provided in k phases to those who wants to opt for the same. The negative customers may arrive during the time when the server is busy in serving a positive customer. This leads to breakdown of the server and thus the server has to be restored (repair) by the repair man. Some moments may be taken by the repair man to initiate the repair process, leading to delay in repair. In our work, firstly we have calculated performance measures like long run probabilities and orbit size along with some reliability indices. Then a relative study between the exact expected waiting time and approximate expected waiting time of the system is presented via maximum entropy approach. Also we perform cost optimization using particle swarm optimization (PSO method). Few numerical results are also provided.

Optoelectronic integration, in which optoelectronic devices such as lasers and photodiodes are integrated with different optoelectronic and/or electronic devices together, is expected to be a key technology in developing future lightwave systems. This is because of its potential advantages in realizing high-performance, high-manufacturability and high-functionality in optoelectronic components, which have not been developed fully due to the limit of using conventional discrete devices and assembly technique. Optoelectronic integrated transmitters and receivers are currently being developed for lightwave telecommunication and interconnection applications by a number of researchers and recent progresses in both the performance and the fabrication technology are encouraging. For example, LSI level integration has been demonstrated in GaAs-based receivers and 5- to 10-Gb/s rate operations have been shown for InP-based integrated lasers. Also a variety of optical processing functions can be implemented by optoelectronic integration. Optical logic elements based on integrated lasers and also waveguide-based circuits for wavelength-multiplexing and optical heterodyne detection are such examples. Technological challenges in optoelectronic integration will lead to a generation of future advanced optical systems for not only communication but also switching and computing. This paper describes the recent progress of this technology and discusses future directions.

Information technology has an increasing impact in the development of rural areas but the development and implementation of telematic services in these areas present special problems such as the appropriate mix of communication technologies, the commercial prospects of recovering the cost of investment, the social problems etc., which currently limit their effective use. With the recent introduction of narrowband ISDN (Integrated Services Data Networks) in Europe it is now possible to offer various services on a single subscriber line. In addition, with the development of both high reliable fibre-optic transmission and very fast switching systems, the introduction of broadband ISDN can also be considered. Unfortunately, the less favoured regions of EC (European Community) lack infrastructure. The development in these areas will be a gradual process. Large investments will be required, and the systems installed will have a lifetime of some decades. Therefore the right decisions on the chosen technologies and on the appropriate system configurations have to be taken to ensure success. In this work, the teleworking prospects as an IT tool for rural development are studied in detail. The motivation, the technology and the prosperity of teleworking in the less favoured regions of the EC are analysed and discussed. The analysis considers the existing telecommunication infrastructure in each one of the six peripheral member states in relation with the development and implementation of some important telematic systems in these areas. The main features of the proposed technologies as well as the establishment of the possible cost effective strategies for IBC (Integrated Broadband Communication) implementation in rural areas is also provided. It appears that teleworking is a key element for rural development and can be implemented through the realization of the IBCNs (IBC Networks). By taking lessons from some of the most important experimental initiatives which have already been introduced in some countries, useful recommendations in the policy to be adopted by the EC are drawn and presented.

Abstract Background: The telehealth approach offers enhanced service delivery for older patients living in rural areas. Purpose: We conducted a pilot study to evaluate the feasibility of using the Zenbo robot to improve the quality of care of elderly individuals with dementia. Methodology: In this study, we developed a digital solution on service robots and smart devices, which can leverage the capacity of the user-friendly interactive interface and digital dialog system. A group of eleven volunteered older adults was selected for this study. To assess the likability and acceptance of the Zenbo, we conducted a one-on-one (robot vs human) pilot study in our long-term care stations. Each participant engaged in conversational interactions for five consecutive days and completed a survey of 12 questions about the experiences they had with the Zenbo, at the beginning and the end of the study respectively. Results: Subjects with lower GDS-15 scores have more positive attitudes toward the robot before the intervention. 27% of older adults had an increase in positive attitudes toward the interaction with the Zenbo robot. With the aid of teleoperated mobile robotic systems at home, the innovative service model can be achieved through telecommunication between primary health professionals or caregivers at remote locations and psychiatrists at the medical center to make the seamless care environment real. Conclusion: The IoT technologies can be used to assist physicians in switching from a hospital-centered model of care to a home-based service for older people with dementia. It merits more future clinical trials and usability tests.

During all periods of the study of telecommunications systems traffic, the analysis was based on mass service theory. The subjects of the study here are request flows to be processed by some limited performance resources. Resource constraints and the random nature of requests’ receipt lead to refusals in processing or queues. The first works devoted to the analysis of teletraffic belong to A. K. Erlang. Request flows represented flows of requests for connections in networks with channel switching. Since requests were received from a large number of independent users, the flows of such requests could be defined as stationary, ordinary with no effect, or as recurring requests, with an exponential distribution of time intervals between neighboring requests. Connection request flows to a telephone exchange node are a superposition of a large number of low-intensity flows from independent users. Therefore, the fixed Poisson flow model describes the real flows in telephone exchanges with channel switching quite well. Therefore, the stationary Poisson flow model describes real flows in telephone exchanges with channel switching rather well. The emergence of telecommunications networks with packet switching, especially multiservice networks, showed the impossibility of using Poisson flow models for their analysis. The article is devoted to the analysis of delays in queues of queuing systems with correlated stationary flows of general type requests. The traffic of packets in multiservice networks is typically characterized by a high degree of correlation. On the basis of interval methods of analysis, the relations generalizing the Khinchin-Pollaczek formula for the average value of waiting time in queuing systems with flows of the general kind of requests are obtained. The main parameters to be analyzed when outputting the above formulas are time intervals between neighboring requests. It is shown that the values of time delays in queues depend on the dispersion and dispersion index of a random value characterizing the degree of additional maintenance of processed requests.

Aim. The paper examines matters related to the definition of the architecture and requirements for data communication networks as part of intelligent mass transit management systems. Methods. The paper suggests a network architecture using multiprotocol label switching (MPLS) technology and traffic routing. If the core of a local area network is implemented using fully-connected topology, the use of flow labels allows predefining information exchange routes between servers and applications of an information and telecommunications network (ITS). Multiprotocol label switching (MPLS) is the foundation of control and information acquisition networks of ITS. That allows adopting common interfaces to the subsystems that perform various functions within an ITS, e.g., control and diagnostics, minimizing the time of information delivery to management servers and sending critical control commands, as well as using common Ethernet or 4G/5G wireless interfaces. Conclusions. The path installation/removal principle, when applied to critical facilities, significantly complicates attacks and collection of information on the network structure of ITS.

In this paper we address the problem of increasing software maintenance costs in a custom software development environment, and develop a stochastic decision model for the maintenance of information systems. Based on this modeling framework, we derive an optimal decision rule for software systems maintenance, and present sensitivity analysis of the optimal policy. We illustrate an application of this model to a large telecommunications switching software system, and present sensitivity analysis of the optimal state for major upgrade derived from our model. Our modeling framework also allows for computing the expected time to perform major upgrade to software systems.

Network effects and switching costs are two major economic forces in information technology industries. Although the consequences of these mechanisms on competition and firm strategy have been well documented in the literature, research on their impact on customer behavior has received less attention. In this study, the authors investigate the role of personal network effects and switching costs in explaining customer choice in the Spanish mobile telecommunications industry. Personal network effects are present when an individual user's utility increases more when some individuals adopt (social network) than when others do. Switching costs refer to costs associated with the process of switching from one provider to another. In addition, this paper studies the drivers of personal network effects and switching behavior. The results reveal that personal network effects and switching costs play a key role in determining mobile users’ choice: the probability that a customer selects a mobile phone company increases with the number of members of her social network already subscribed to that firm, and switching costs are significantly present in the mobile phone market making switching providers costly. Concerning the drivers of both mechanisms, the authors find that relationship characteristics (length, depth and breadth) and demographics differently affect personal network effects perceptions and consumer switching behavior. Implications for decision makers are discussed.

The development of high-speed rail requires introduction of new telecommunications technology implemented in an integrated digital technological communication system (IDTC). Features of building such systems comprise provision of switching optical data channels using photonic switches (PS). Switching processes in PS occur at the photon (optical) level. A feature of construction of PS is the use of multi-tier topologies, performed using binary switches (BSs). BS is the simplest switching element with the number of input/output ports equal to one or two. The concepts for constructing PS are based on the technology of the well-known switching circuits using BS whose architecture and topology are assigned the names of their creators (Benes, Spanke, Spanke–Benes architecture, Clos network, etc. With an increase in PS capacity, its structure becomes more complicated: the number of links in the switching circuit, the total number of BSs, the length of switching routes, and the redundancy factor increase. In addition, it becomes necessary to calculate the probabilities of the occurrence of internal blocking in switching circuits, speed of switching optical signals, the value of attenuation of the optical signal in PS circuit, etc. The objective of the study was to develop methods of analysis and synthesis of switching circuits of photonic switches using the example of a circuit of Spanke architecture of a given capacity with calculation of the probabilities of occurrence of internal blocking. The authors used general scientific and engineering methods of mathematical modelling, probability and queuing theory and an example of an algorithm for analysing the structures of Spanke topology with capacities from 4×4 to 128×128. Their topological and probabilistic characteristics (the number of links in the switching circuit, the total number of BS, the length of the switching routes, the probability of occurrence of internal blocking in PS circuits) have been determined. The results of calsulations are presented in the form of tables. The developed methods of analysis and synthesis can be used in the study of similar switching circuits built using BS.

Vienna converters have several advantages, including low construction costs, improved total harmonics, and considerable reliability. Generally, they are used in applications with a high switching frequency, particularly in telecommunications, and their use in power generation systems is recent but promising. They can be an interesting solution for medium and large wind power systems as they have the advantage of a high power density compared to traditional two-level converters. In this paper, a wind energy production system based on a Vienna rectifier and the permanent magnet synchronous generator (PMSG) is proposed. The main objective of this work is to evaluate the performance of the vector control strategy of the PMSG associated with the Vienna rectifier considering the real conditions of wind power systems. The feasibility and effectiveness of the proposed control strategy are evaluated through the simulations in MATLAB/Simulink and experimental tests based on a laboratory prototype. The outcomes present interesting performances in terms of dynamics and stability.

DC-DC buck converters have wide applications in portable electronic devices, battery chargers, and telecommunications. However, single-phase DC-DC buck converters have some drawbacks, especially in high current applications, where the increase in the size of the inductor will increase power losses, which significantly affects the overall efficiency of the converter. The multiphase configuration offers several advantages, such as reduction in output voltage ripple, input current ripple, conduction loss, and the physical size of the hardware. This paper presents an analysis of the power losses of the multiphase DC-DC buck converter with output power ranging between 50 watts to 250 watts. To verify the effectiveness of the multiphase converter, performance analysis was done using OrCAD PSpice software, where the number of phases was limited to five phases. This paper focused on power losses in the converter, namely conduction losses in diodes and MOSFETs, switching loss in MOSFETs, as well as losses in the inductor and capacitor. The relationship between the number of phases and factors of switching frequency, output, and the components’ internal resistance was also highlighted and discussed in detail.

The purpose of the research is to analyze the comparison of technology, network and security aspect between CDMA and GSM (Global System for Car communication). Using a comparative analysis research method between CDMA and GSM technologies that includes comparisons of network, technology, and security aspects. Using references from previous research on cellular telecommunications, the introduction of CDMA and GSM technologies to aspects of technology, networking and security. The results show that the technological aspect, CDMA used advanced spectrum technology that can provide superior sound quality and GSM uses a spectrum division technology that makes communication constant. From the network aspect, CDMA used direct-spreading spectrum (DS-CDMA) and GSM network is divided into three main systems: switching system (SS), base station system (BSS), and operating system and support (OSS). As well as security aspects, the GSM uses A3 and A8 algorithms for authentication and A5 algorithms were used in the process of sending information.But the security system using this algorithm, found weaknesses that allow data tapping or customer identity fraud. While CDMA offers aspects of network security by developing encryption algorithms.For encryption techniques used Rijndael algorithm is safe and very fast. A3 and A8 algorithms can recognize the customer's identity well, and the A5 algorithm can transmit the accuracy of information between MS and BTS.

Recently, optical MEMS devices have gained considerable attention in the telecommunications industry—particularly in the optical networking and switching arenas. Since optical MEMS are micro-systems which rely on high precision optics, electronics and mechanics working in close concert, these emerging devices pose some unique packaging challenges yet to be addressed by the general packaging industry. Optical MEMS packages often are required to provide both optical and electrical access, hermeticity, mechanical strength, dimensional stability, and long-term reliability. Hermetic optical access necessitates the use of metallized and anti-reflection coated windows, and ever-increasing electrical I/O count has prompted the use of higher density substrate/package technologies. Taking these requirements into consideration, we explore three ceramic packaging technologies, namely high-temperature co-fired ceramic (HTCC), low-temperature co-fired ceramic (LTCC), and thin-film ceramic technologies. In this paper, we describe some optical MEMS packages designed using these three technologies and discuss their substrate designs, package materials, ease of integration and assembly.

As an effectual simple wireless equivalent created in the telecommunications (telephone) industry, Wireless Asynchronous Transfer Mode (WATM) is utilized to stream unified traffics like video, data, and voice data. In the asynchronous data transfer mode, voice data transfer a packet with the same medium, and data share the networks and burst data. Effective WATM data transmission requires an extensive array of designs, techniques used for control, and simulation methodologies. The congestion of the network is among the key challenges that lower the entire WATM performance during this procedure, in addition to the delay in cell and the overload of traffic. The congestions cause cell loss, and it requires expensive switches compared to the LAN. Consequently, in this current study, the application of an effectual switching model together with a control mechanism that possesses multiple accesses is employed. The multiple access process and switching model are utilized to establish an effective data sharing process with minimum complexity. The switching model uses the synchronous inputs and output ports with buffering to ensure the data sharing process. The traffic in the network is decreased, and the loss of packets in the cells is efficiently kept to a minimum by the proposed technique. The system being discussed is employed through the utilization of software employed using OPNET 10.5 simulation, with the valuation of the WATM along with the investigational outcomes accordingly. The system's efficiency is assessed by throughput, latency, cell loss probability value (CLP), overhead network, and packet loss. Thus, the system ensures the minimum packet loss (0.1 %) and high data transmission rate (96.6 %)

The goal is to improve the quality of information interaction of objects by increasing the reliability of message delivery to recipients and bandwidth through the integration of networks using various signals and physical channels. A search for new technical solutions for the creation of integrated (hybrid) communication technologies aimed at expanding the possibilities for creating adaptive, self organizing, resistant to destabilizing factors communication systems with an increased quality of services provided in vast areas was carried out. The method of solving the tasks is based on the analysis of development trends and forecasting the requirements for integrated mobile communication systems. The novelty lies in the development and evaluation of options for building the structures of integrated communication systems, represented by diverse, complementary subsystems using various methods of channel separation, including in physical environments, as well as algorithms for their operation. Key findings. A set of technologies for the development of coastal integrated communication systems has been developed: the structure of the system based on a hybrid mesh topology; the basic form of the carrier signal with controlled parameters depending on the physical channel; the principle of control of orthogonal signals in adjacent channels of switching and relay nodes, as well as between network nodes; hydroacoustic communication method. Hydroacoustic communication for coastal areas is a potential for increasing the number of simultaneously used information channels per unit of the volume of interaction of vital objects and makes it possible to connect satellite, air, surface, underwater and bottom subsystems of telecommunications. The con ducted studies have shown the stability of the proposed methods in conditions of excess of interference over the signal.

The development of important applications related to optical telecommunications and optical signal processing rely increasingly on nonlinear optical phenomena underlying these optical functions such as frequency conversion and modulation, amplification and emission, multiplexing and directional switching, optical logical gates, and others. This will depend on the design, elaboration and availability of new materials displaying enhanced nonlinearities to be subsequently integrated into waveguiding devices. Organic materials are noteworthy candidates in this context, provided their microscopic and macroscopic properties are properly optimized with respect to the type of application required. Among the key-factors in the development of these materials are the quasi-unlimited variety of molecular structures accessible by organic synthesis, the possibility to connect specific nonlinear properties to other kinds of functionalities which are of crucial importance for the development of commercial devices (e.g., compatibility with other materials used in integrated optical circuits such as semi-conductors), and their exceptionally large second-order, non-resonant nonlinear response. Such performances are strongly dependent on a better understanding of the ‘molecular engineering’, rules, correlating molecular structures to their nonlinear optical properties towards optimization of the microscopic second order polarizabilities β and third-order polarizabilities γ. We will present in the following some examples of the most recent developments of highly efficient nonlinear molecules, ranging from purely one-dimensional structures such as polyenes to fully three-dimensional systems, taking full advantage of the tensorial character of the microscopic or macroscopic susceptibility tensors.

The broad view of chum rate measures the amount of individuals or items comes out of a collective group over a predefined time period. Many challenges linked with the churn rates in the telecom industry rise in increasing competition with the elimination of switching costs. The customer loyalty over the telecom industry exists along with the service provider struggling to offer improved services with the lower cost. Many author reviews depends on the churn rate prediction in the field of telecommunication sector discussed with the paper. The paper talk about an idea related with an application of churn rate for the technical review.

The article considers the issues of statistical modeling of traffic in telecommunication networks with packet switching. The simulation results are used in the development of network technical condition management systems, in particular, diagnostics, troubleshooting and network configuration management. The peculiarities of congestion control of separate network segments are emphasized. With improper analysis the overload condition can be mistaken for equipment failure. Therefore, control and elimination of congestion is a statistical task. The concept of end-to-end network diagnostics is considered. This concept provides for effective assessment of the quality of functioning of all network components taking into account their interrelationships. The main issues are the interaction of equipment, inefficient configuration, improper network organization and user operation. Methods of traffic statistical control characteristics based on perforated and marker bucket algorithms are analyzed. A feature of these algorithms is the formation of a strict output stream at a rate that does not depend on the non-uniformity of the input stream. The possibility of improving the token bucket algorithm by adapting to changes in the statistical characteristics of traffic is shown. To solve this problem, statistical mathematical models of network traffic are built. Data traffic circulating in telecommunication networks by packet switching has self-similar (fractal) properties. The self-similar process retains its properties when considered at different time scales (invariance to scale changes). The degree of statistical stability of the process with multiple scaling is determined by the Hirst parameter (the self-similarity parameter). Graphs of statistical characteristics of low-speed and high-speed data traffic are obtained. Their comparative analysis is carried out.

Within recent years there has been a significant amount of interest in applying the new and developing photonics technology for telecommunications switching. As the transmission plant has converted its facilities to fibre there is an economic interest in completing the optical path through the switching system to the terminal facilities without requiring optical-to-electrical conversions. This paper reviews some of the proposed switching systems that use time-multiplexed switching and discusses how, and if, they could fit into current telecommunications networks.

People have used technology to improve themselves throughout the human history. From the ancient times, human beings tried to get their work done by human slaves or inanimate machines. To build intelligent agents each new technology has been exploited. Clockwise, hydraulics, telephone switching systems, holograms, analog computers and digital computers have all been suggested both as mechanisms for intelligent agent and as technological metaphors for intelligence. A new invention of computer system is known as Artificial Intelligence that can perform tasks with the help of human intelligence. Artificial Intelligence associated with computer systems which includes various types of intelligence: systems that understand new concepts and tasks, systems that are able to give reason and draw useful conclusion about the world around us, systems which can learn a natural language and comprehend a visual scene. Artificial Intelligence means intelligence that is demonstrated by machines. This is a device that recognizes its environment and takes action that increases the chances of achieving its goal. The research goal of Artificial Intelligence is to create technology which helps computers and machines to perform various tasks in an intelligent manner. Artificial Intelligence analysis the intelligent acts of computational agents. Computational agent is one whose decisions about his/her actions can be explained in terms of computation. His actions, firstly, may be broken down into primary operation that further can be applied in a physical device. Computations have many forms, for example: In humans, it is in the form of “wetware” and in computers it is in the form of “hardware”. Greatest advances have occurred in the field of game playing. Super computer named Deep Blue defeated world chess champion Gary Kasparov in May, 1997. This research article explains history, features and goals of artificial intelligence. It also explains various types of artificial intelligence like reactive machine,limited memory, theory of mind and self- awareness. This article focus on application of artificial intelligence in many fields like literacy, finance, heavy industries, hospitals, news, publishing, transportations, telecommunication maintenance, telephone and online customer services etc.

0. IntroductionIf we follow the line of much literature surrounding airports and urban mobility, the emphasis often falls on the fact that these spaces are designed to handle the mega-scale and super-human pace of mass transit. Airports have rightly been associated with velocity, as zones of rapid movement managed by enormous processing systems that guide bodies and things in transit (Pascoe; Pearman; Koolhaas; Gordon; Fuller & Harley). Yet this emphasis tends to ignore the spectrum of tempos and flows that are at play in airport terminals — from stillness to the much exalted hyper-rapidity of mobilized publics in the go-go world of commercial aviation.In this photo essay I'd like to pull a different thread and ask whether it's possible to think of aeromobility in terms of “uneven, differential mobility” (Bissell 280). What would it mean to consider waiting and stillness as forms of bodily engagement operating over a number of different scales and temporalities of movement and anticipation, without privileging speed over stillness? Instead of thinking mobility and stillness as diametrically opposed, can we instead conceive of them as occupying a number of different spatio-temporal registers in a dynamic range of mobility? The following is a provisional "visual ethnography" constructed from photographs of air terminal light boxes I have taken over the last five years (in Amsterdam, London, Chicago, Frankfurt, and Miami). Arranged into a "taxonomy of differentiality", each of these images comes from a slightly different angle, mode or directionality. Each view of these still images displayed in billboard-scale light-emitting devices suggests that there are multiple dimensions of visuality and bodily experience at play in these image-objects. The airport is characterized by an abundance of what appears to be empty space. This may be due to the sheer scale of mass transport, but it also arises from a system of active and non-active zones located throughout contemporary terminals. This photo series emphasises the "emptiness" of these overlooked left-over spaces that result from demands of circulation and construction.1. We Move the WorldTo many travellers, airport gate lounges and their surrounding facilities are loaded with a variety of contradictory associations and affects. Their open warehouse banality and hard industrial sterility tune our bodies to the vast technical and commercial systems that are imbricated through almost every aspect of contemporary everyday life.Here at the departure gate the traveller's body comes to a moment's rest. They are granted a short respite from the anxious routines of check in, body scans, security, information processing, passport scanning, itineraries, boarding procedures and wayfaring the terminal. The landside processing system deposits them at this penultimate point before final propulsion into the invisible airways that pipe them into their destination. We hear the broadcasting of boarding times, check-in times, name's of people that break them away from stillness, forcing people to move, to re-arrange themselves, or to hurry up. Along the way the passenger encounters a variety of techno-spatial experiences that sit at odds with the overriding discourse of velocity, speed and efficiency that lie at the centre of our social understanding of air travel. The airline's phantasmagorical projections of itself as guarantor and enabler of mass mobilities coincides uncomfortably with the passenger's own wish-fulfilment of escape and freedom.In this we can agree with the designer Bruce Mau when he suggests that these projection systems, comprised of "openings of every sort — in schedules, in urban space, on clothes, in events, on objects, in sightlines — are all inscribed with the logic of the market” (Mau 7). The advertising slogans and images everywhere communicate the dual concept that the aviation industry can deliver the world to us on time while simultaneously porting us to any part of the world still willing to accept Diners, VISA or American Express. At each point along the way these openings exhort us to stop, to wait in line, to sit still or to be patient. The weird geographies depicted by the light boxes appear like interpenetrating holes in space and time. These travel portals are strangely still, and only activated by the impending promise of movement.Be still and relax. Your destination is on its way. 2. Attentive AttentionAlongside the panoramic widescreen windows that frame the choreography of the tarmac and flight paths outside, appear luminous advertising light boxes. Snapped tightly to grid and locked into strategic sightlines and thoroughfares, these wall pieces are filled with a rotating menu of contemporary airport haiku and ersatz Swiss graphic design.Mechanically conditioned air pumped out of massive tubes creates the atmosphere for a very particular amalgam of daylight, tungsten, and fluorescent light waves. Low-oxygen-emitting indoor plants are no match for the diesel-powered plant rooms that maintain the constant flow of air to every nook and cranny of this massive processing machine. As Rem Koolhaas puts it, "air conditioning has launched the endless building. If architecture separates buildings, air conditioning unites them" (Koolhaas). In Koolhaas's lingo, these are complex "junkspaces" unifying, colliding and coalescing a number of different circulatory systems, temporalities and mobilities.Gillian Fuller reminds us there is a lot of stopping and going and stopping in the global circulatory system typified by air-terminal-space.From the packing of clothes in fixed containers to strapping your belt – tight and low – stillness and all its requisite activities, technologies and behaviours are fundamental to the ‘flow’ architectures that organize the motion of the globalizing multitudes of today (Fuller, "Store" 63). It is precisely this functional stillness organised around the protocols of store and forward that typifies digital systems, the packet switching of network cultures and the junkspace of airports alike.In these zones of transparency where everything is on view, the illuminated windows so proudly brought to us by J C Decaux flash forward to some idealized moment in the future. In this anticipatory moment, the passenger's every fantasy of in-flight service is attended to. The ultimate in attentiveness (think dimmed lights, soft pillows and comfy blankets), this still image is captured from an improbable future suspended behind the plywood and steel seating available in the moment —more reminiscent of park benches in public parks than the silver-service imagined for the discerning traveller.3. We Know ChicagoSelf-motion is itself a demonstration against the earth-binding weight of gravity. If we climb or fly, our defiance is greater (Appleyard 180).The commercial universe of phones, cameras, computer network software, financial instruments, and an array of fancy new gadgets floating in the middle of semi-forgotten transit spaces constitutes a singular interconnected commercial organism. The immense singularity of these claims to knowledge and power loom solemnly before us asserting their rights in the Esperanto of "exclusive rollover minutes", "nationwide long distance", "no roaming charges" and insider local knowledge. The connective tissue that joins one part of the terminal to a commercial centre in downtown Chicago is peeled away, revealing techno-veins and tendrils reaching to the sky. It's a graphic view that offers none of the spectacular openness and flights of fancy associated with the transit lounges located on the departure piers and satellites. Along these circulatory ribbons we experience the still photography and the designer's arrangement of type to attract the eye and lure the body. The blobby diagonals of the telco's logo blend seamlessly with the skyscraper's ribbons of steel, structural exoskeleton and wireless telecommunication cloud.In this plastinated anatomy, the various layers of commercially available techno-space stretch out before the traveller. Here we have no access to the two-way vistas made possible by the gigantic transparent tube structures of the contemporary air terminal. Waiting within the less travelled zones of the circulatory system we find ourselves suspended within the animating system itself. In these arteries and capillaries the flow is spread out and comes close to a halt in the figure of the graphic logo. We know Chicago is connected to us.In the digital logic of packet switching and network effects, there is no reason to privilege the go over the stop, the moving over the waiting. These light box portals do not mirror our bodies, almost at a complete standstill now. Instead they echo the commercial product world that they seek to transfuse us into. What emerges is a new kind of relational aesthetics that speaks to the complex corporeal, temporal, and architectural dimensions of stillness and movement in transit zones: like "a game, whose forms, patterns and functions develop and evolve according to periods and social contexts” (Bourriaud 11). 4. Machine in the CaféIs there a possible line of investigation suggested by the fact that sound waves become visible on the fuselage of jet planes just before they break the sound barrier? Does this suggest that the various human senses are translatable one into the other at various intensities (McLuhan 180)?Here, the technological imaginary contrasts itself with the techno alfresco dining area enclosed safely behind plate glass. Inside the cafes and bars, the best businesses in the world roll out their biggest guns to demonstrate the power, speed and scale of their network coverage (Remmele). The glass windows and light boxes "have the power to arrest a crowd around a commodity, corralling them in chic bars overlooking the runway as they wait for their call, but also guiding them where to go next" (Fuller, "Welcome" 164). The big bulbous plane sits plump in its hangar — no sound barriers broken here. It reassures us that our vehicle is somewhere there in the network, resting at its STOP before its GO. Peeking through the glass wall and sharing a meal with us, this interpenetrative transparency simultaneously joins and separates two planar dimensions — machinic perfection on one hand, organic growth and death on the other (Rowe and Slutsky; Fuller, "Welcome").Bruce Mau is typical in suggesting that the commanding problem of the twentieth century was speed, represented by the infamous image of a US Navy Hornet fighter breaking the sound barrier in a puff of smoke and cloud. It has worked its way into every aspect of the design experience, manufacturing, computation and transport.But speed masks more than it reveals. The most pressing problem facing designers and citizens alike is growth — from the unsustainable logic of infinite growth in GDP to the relentless application of Moore's Law to the digital networks and devices that define contemporary society in the first world. The shift of emphasis from speed to growth as a time-based event with breaking points and moments of rupture has generated new possibilities. "Growth is nonlinear and unpredictable ... Few of us are ready to admit that growth is constantly shadowed by its constitutive opposite, that is equal partners with death” (Mau 497).If speed in part represents a flight from death (Virilio), growth invokes its biological necessity. In his classic study of the persistence of the pastoral imagination in technological America, The Machine in the Garden, Leo Marx charted the urge to idealize rural environments at the advent of an urban industrialised America. The very idea of "the flight from the city" can be understood as a response to the onslaught of technological society and it's deathly shadow. Against the murderous capacity of technological society stood the pastoral ideal, "incorporated in a powerful metaphor of contradiction — a way of ordering meaning and value that clarifies our situation today" (Marx 4). 5. Windows at 35,000 FeetIf waiting and stillness are active forms of bodily engagement, we need to consider the different layers of motion and anticipation embedded in the apprehension of these luminous black-box windows. In The Virtual Window, Anne Friedberg notes that the Old Norse derivation of the word window “emphasizes the etymological root of the eye, open to the wind. The window aperture provides ventilation for the eye” (103).The virtual windows we are considering here evoke notions of view and shelter, open air and sealed protection, both separation from and connection to the outside. These windows to nowhere allow two distinct visual/spatial dimensions to interface, immediately making the visual field more complex and fragmented. Always simultaneously operating on at least two distinct fields, windows-within-windows provide a specialized mode of spatial and temporal navigation. As Gyorgy Kepes suggested in the 1940s, the transparency of windows "implies more than an optical characteristic; it implies a broader spatial order. Transparency means a simultaneous perception of different spatial locations" (Kepes 77).The first windows in the world were openings in walls, without glass and designed to allow air and light to fill the architectural structure. Shutters were fitted to control air flow, moderate light and to enclose the space completely. It was not until the emergence of glass technologies (especially in Holland, home of plate glass for the display of commercial products) that shielding and protection also allowed for unhindered views (by way of transparent glass). This gives rise to the thesis that windows are part of a longstanding architectural/technological system that moderates the dual functions of transparency and separation. With windows, multi-dimensional planes and temporalities can exist in the same time and space — hence a singular point of experience is layered with many other dimensions. Transparency and luminosity "ceases to be that which is perfectly clear and becomes instead that which is clearly ambiguous" (Rowe and Slutsky 45). The light box air-portals necessitate a constant fluctuation and remediation that is at once multi-planar, transparent and "hard to read". They are informatic.From holes in the wall to power lunch at 35,000 feet, windows shape the manner in which light, information, sights, smells, temperature and so on are modulated in society. "By allowing the outside in and the inside out, [they] enable cosmos and construction to innocently, transparently, converge" (Fuller, "Welcome" 163). Laptop, phone, PDA and light box point to the differential mobilities within a matrix that traverses multiple modes of transparency and separation, rest and flight, stillness and speed.6. Can You Feel It?Increasingly the whole world has come to smell alike: gasoline, detergents, plumbing, and junk foods coalesce into the catholic smog of our age (Illich 47).In these forlorn corners of mobile consumption, the dynamic of circulation simultaneously slows and opens out. The surfaces of inscription implore us to see them at precisely the moment we feel unseen, unguided and off-camera. Can you see it, can you feel it, can you imagine the unimaginable, all available to us on demand? Expectation and anticipation give us something to look forward to, but we're not sure we want what's on offer.Air travel radicalizes the separation of the air traveller from ground at one instance and from the atmosphere at another. Air, light, temperature and smell are all screened out or technologically created by the terminal plant and infrastructure. The closer the traveller moves towards stillness, the greater the engagement with senses that may have been ignored by the primacy of the visual in so much of this circulatory space. Smell, hunger, tiredness, cold and hardness cannot be screened out.In this sense, the airplanes we board are terminal extensions, flying air-conditioned towers or groundscrapers jet-propelled into highways of the air. Floating above the horizon, immersed in a set of logistically ordained trajectories and pressurized bubbles, we look out the window and don't see much at all. Whatever we do see, it's probably on the screen in front of us which disconnects us from one space-time-velocity at the same time that it plugs us into another set of relations. As Koolhaas says, junkspace is "held together not by structure, but by skin, like a bubble" (Koolhaas). In these distended bubbles, the traveler momentarily occupies an uncommon transit space where stillness is privileged and velocity is minimized. The traveler's body itself is "engaged in and enacting a whole kaleidoscope of different everyday practices and forms" during the course of this less-harried navigation (Bissell 282).7. Elevator MusicsThe imaginary wheel of the kaleidoscope spins to reveal a waiting body-double occupying the projected territory of what appears to be a fashionable Miami. She's just beyond our reach, but beside her lies a portal to another dimension of the terminal's vascular system.Elevators and the networks of shafts and vents that house them, are to our buildings like veins and arteries to the body — conduits that permeate and structure the spaces of our lives while still remaining separate from the fixity of the happenings around them (Garfinkel 175). The terminal space contains a number of apparent cul-de-sacs and escape routes. Though there's no background music piped in here, another soundtrack can be heard. The Muzak corporation may douse the interior of the elevator with its own proprietary aural cologne, but at this juncture the soundscape is more "open". This functional shifting of sound from figure to ground encourages peripheral hearing, providing "an illusion of distended time", sonically separated from the continuous hum of "generators, ventilation systems and low-frequency electrical lighting" (Lanza 43).There is another dimension to this acoustic realm: “The mobile ecouteur contracts the flows of information that are supposed to keep bodies usefully and efficiently moving around ... and that turn them into functions of information flows — the speedy courier, the networking executive on a mobile phone, the scanning eyes of the consumer” (Munster 18).An elevator is a grave says an old inspector's maxim, and according to others, a mechanism to cross from one world to another. Even the quintessential near death experience with its movement down a long illuminated tunnel, Garfinkel reminds us, “is not unlike the sensation of movement we experience, or imagine, in a long swift elevator ride” (Garfinkel 191).8. States of SuspensionThe suspended figure on the screen occupies an impossible pose in an impossible space: half falling, half resting, an anti-angel for today's weary air traveller. But it's the same impossible space revealed by the airport and bundled up in the experience of flight. After all, the dimension this figures exists in — witness the amount of activity in his suspension — is almost like a black hole with the surrounding universe collapsing into it. The figure is crammed into the light box uncomfortably like passengers in the plane, and yet occupies a position that does not exist in the Cartesian universe.We return to the glossy language of advertising, its promise of the external world of places and products delivered to us by the image and the network of travel. (Remmele) Here we can go beyond Virilio's vanishing point, that radical reversibility where inside and outside coincide. Since everybody has already reached their destination, for Virilio it has become completely pointless to leave: "the inertia that undermines your corporeity also undermines the GLOBAL and the LOCAL; but also, just as much, the MOBILE and the IMMOBILE” (Virilio 123; emphasis in original).In this clinical corner of stainless steel, glass bricks and exit signs hangs an animated suspension that articulates the convergence of a multitude of differentials in one image. 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