Large Telecommunication Networks Research Articles

Identification of Aggregate Urban Mobility Patterns of Nonregular Travellers from Mobile Phone Data

Over the last two decades, mobile phone data have appeared to be a promising data source for mobility analysis. The structure, abundance, and accessibility of call detail records (CDRs) make them particularly suitable for such use. However, their exploitation is often limited to estimating origin–destination matrices of a restricted part of the population: regular travellers. Although these studies provide valuable information for policymakers, their scope remains limited to this subpopulation analysis. In the present work, we develop a collective mobility reconstruction method adapted to nonregular travellers. The method relies on the notion of the detour ratio, which makes it robust to the lack of mobile phone data as well as its application to large instances (large and dense telecommunication networks). It is used to conduct a longitudinal analysis of the macroscopic mobility patterns in Santiago de Cali, Colombia, thanks to call detail data shared by communication provider CLARO as part of a research project conducted by Citepa, Paris, the Green City Big Data Project.

СВІТОВИЙ ДОСВІТ ВПРОВАДЖЕННЯ АРМ В УПРАВЛІННЯ ПІДПРИЄМСТВАМИ ЦИВІЛЬНОЇ АВІАЦІЇ

Objective. The study is devoted to determining the features of the global experience of using WA for the management of civil aviation enterprises, which will ensure an increase in the efficiency of operations, reduce the costs of managing cases due to the automation of information processing processes, ensure reliable accounting and control of information at all levels of management, and increase the efficiency of data exchange between individual units , branches and central office. Methods. The research uses methods of analysis and synthesis in order to substantiate the theoretical provisions of the use of WA and information technology as an element of increasing the efficiency of management of civil aviation enterprises. Automation methods of WA from the company SITA, CHAMP Cargo systems, Aviareto, CertiPath. The complex system of using WA as a general information management element of the enterprise in the field of civil aviation is substantiated. Results. In order to improve the quality of service to consumers of air transport services, airlines and especially airports need to regularly introduce advanced information systems and technologies into the organizational process of providing air transportation. The international company SITA is the world leader in the field of information and telecommunication solutions for the air transport industry. SITA provides comprehensive services to airlines, airports, government entities and global distribution systems, providing access to a large telecommunications network and providing consulting services for the development, implementation and integration of technological solutions. Among the applications and services intended for airlines and airports are passenger registration systems and integrated baggage management systems, air traffic management systems, communication systems with ground services, as well as distribution and fare management systems. Scientific novelty. The system of adaptation of WA, in accordance with world practice, to the activity of civil aviation entities of Ukraine has been substantiated. Practical significance. It was established that the WA system contributes to the combination of these features within the framework of one integrated program. It is based on a single database, so all units/departments will be able to freely share information, communicate with each other, etc. It has been proven that this integrated approach to the introduction of WA into the practice of civil aviation enterprises using world experience will ensure a high level of return in the future, especially if it is correctly installed and used. Keywords: aviation enterprise, automated workplace (WA), civil aviation industry, management.

Proposal of multifunctional coherent Nyquist pulse and ultra-high-speed and high-efficiency optical transmission technology

A cornerstone of technological advancement in the last century has been the development of ever faster and higher capacity telecommunications. Being able to transmit large amounts of information, at a good rate over long distances is essential for running many of the services, business and industries that we all rely upon. The development of large national and international telecommunication networks underpins the internet and, with it, the World Wide Web. All this powers a huge range of diverse activities as security services, the entertainment industry, national health services and distribution. As more and more people are connected to this network and more and more information is transmitted between these people, the capacity of the network must increase. This can broadly be split into two categories: access – the laying of cables and construction of mobile towers, technology – the creation of improved data transmitting methods that can transmit more data, at a faster rate, further away. The former is a question of private enterprise and public policy, the latter is the domain of engineers and physicists. Professor Masataka Nakazawa, who is based at the Research Institute of Electrical Communication, Tohoku University in Japan, is a world-leading expert in optical telecommunications. Nakazawa and his team have a mission to create new methods through which data can be transmitted using optical networks, recently they have consistently broken records for speed, capacity and efficiency in their cutting-edge optical communication technologies.

Fusing information from tickets and alerts to improve the incident resolution process

In the context of network incident monitoring, alerts are useful notifications that provide IT management staff with information about incidents. They are usually triggered in an automatic manner by network equipment and monitoring systems, thus containing only technical information available to the systems that are generating them. On the other hand, ticketing systems play a different role in this context. Tickets represent the business point of view of incidents. They are usually generated by human intervention and contain enriched semantic information about ongoing and past incidents. In this article, our main hypothesis is that incorporating tickets information into the alert correlation process will be beneficial to the incident resolution life-cycle in terms of accuracy, timing, and overall incident’s description. We propose a methodology to validate this hypothesis and suggest a solution to the main challenges that appear. The proposed correlation approach is based on the time alignment of the events (alerts and tickets) that affect common elements in the network. For this we use real alert and ticket datasets obtained from a large telecommunications network. The results have shown that using ticket information enhances the incident resolution process, mainly by reducing and aggregating a higher percentage of alerts compared with standard alert correlation systems that only use alerts as the main source of information. Finally, we also show the applicability and usability of this model by applying it to a case study where we analyze the performance of the management staff.

A Novel Long Term Telecommunication Network Planning Framework

The design of large scale telecommunication networks is more than the technical allocation of capacity and path routing. By examining the design and allocation of resources in a broader sense, telecommunication network planning and management can better deliver value to the various stakeholders. This is significant especially when deploying networks in economically marginal areas such are rural, remote, or economically depressed regions. This paper presents a planning framework to systematically incorporate the influences, resources and decisions to effectively build or expand a network. Using a stake holders, input, process, output, customer approach, six key areas of society that derive value from better communication infrastructure in relatively unique manners were identified. These areas include healthcare, education, business, and others. The framework presented defines the inputs and outputs that accounts for the range of influences and outcomes in a network planning process. Inputs are broken down into four areas of concern (technical, market, financial, and application trends) that can influence how a network could be designed, along with four output areas (auxiliary activities, deployment strategies, technical design, and ownership and access). Through an extensive literature survey across many industries this framework was established to incorporate the many social economic and technical factors that influence telecommunication network planning and design.

Towards a Timely Root Cause Analysis for Complex Situations in Large Scale Telecommunications Networks

Large scale telecommunications networks need to be continuously monitored to detect problems and react accordingly to ensure the networks stability. Current monitoring systems are well capable to monitor such large scale installations for simple situations like failing routers, links or abnormal link utilization. However, current systems fail to provide near real-time in-depth root cause analysis for nation scale networks. This is particularly important in cases where the monitoring dashboard is flooded with notifications caused by side-effects of one bigger failure. In our project we develop a processing system capable of providing this root cause analysis in a timely fashion even for large telecommunications networks. To cope with these challenges we defined a specialized processing model for the detection and analysis of complex error situations which is largely based on event stream processing mechanisms. In this paper we discuss the first stage of this process and its initial implementation.

A Review of Corporate Social Responsibility: SingTel Touches Lives

The essay addresses the corporate social responsibility programme of SingTel (Singapore Telecommunications), a “Touching Lives Fund” initiative, which will serve as the chosen CSR (Corporate Social Responsibility) programme to describe, explain, justify and assess ethical decision making and behavior within the programme. It will also highlight the author’s interests, body of knowledge and reflective ability to discuss these ethical issues. SingTel is the largest telecommunications network in Singapore and in Southeast Asia. It has a combined mobile subscriber base of 185.3 million customers from its own operations and regional associates. SingTel has expanded aggressively outside and holds shares in many operators, such as Australian Optus and Cable and Wireless. Literally, almost everyone in Singapore would have a service account with SingTel some time or another. The SingTel “Touching Lives Fund” programme is a fund-raising instrument under SingTel. It was initiated in 2002 for the purpose of raising donations for 30,000 less privileged children and youths aged 2 to 25 by funding programmes such as training and special education, school social work and counseling of youth from families facing problems and other socially-related issues. Till now, the programme has received S$12.8 million from all kinds of donors and given to charities. These donations are driven from various activities held in tandem to its objectivesof raising millions-for each year. According to SingTel, the activities entail the following: SingTel matching dollar for dollar on Flag Day involving all of SingTel employees and their family members; Charity golf events and walks supported by business associates; Customers that use SingTel’s allocated services raise funds; SingTel giving a dollar for every kilogram of old phone directories that were recycled.

Parallel Network Simulation With OMNeT++

This paper reports a new parallel and distributed simulation architecture for OMNeT++, an open-source discrete event simulation environment. The primary application area of OMNeT++ is the simulation of communication networks. Support for a conservative PDES protocol (the Null Message Algorithm) and the relatively novel Ideal Simulation Protocol has been implemented.Placeholder modules, a novel way of distributing the model over several logical processes (LPs) is presented. The OMNeT++ PDES implementation has a modular and extensible architecture, allowing new synchronization protocols and new communication mechanisms to be added easily, which makes it an attractive platform for PDES research, too. We intend touse this framework to harness the computational capacity of highperformance cluster computersfor modeling very large scale telecommunication networks to investigate protocol performance and rare event failure scenarios.

Evaluating Reliability of Telecommunications Networks Using Traffic Path Information

We propose a reliability model for representing telecommunications networks that does not focus on topological information, but rather traffic path information. Mapping from traffic paths to physical elements and capacities enables the model to express simply how terrible performance degradations occur. Existing models, such as probability graph models, and probability-capacity graph models, do not adequately address actual telecommunication network designs. The probability graph model never considers performance degradations, while the probability-capacity model unreasonably assumes that we can estimate performance degradations from only the network topology. This paper also proposes an algorithm for evaluating the reliability of our new model. A numerical example shows that the algorithm is reasonably efficient for even large telecommunications networks.

Reliability, Availability and Cost Analysis of Large Multi-State Systems with Ageing Components

Reliability, Availability and Cost Analysis of Large Multi-State Systems with Ageing ComponentsBasic notions of the system multi-state reliability analysis are introduced. The multi-state series system with degrading components is defined and its exact reliability function is determined. The limit reliability function for large multi-state systems is introduced. An auxiliary theorem on limit reliability function of a large multi-state series system, which is necessary for its approximate reliability evaluation, is presented. On the basis of this auxiliary theorem some corollaries are formulated and proved and then applied to approximate reliability and availability determination of a large multi-state series system. Evaluations are given of a multi-state system reliability function, its mean lifetimes in the state subsets and their standard deviations, mean value and variance of the lifetime up to and the number of exceeding the system reliability critical state and its availability coefficient. The cost analysis of a multi-state series system is performed as well. The results are applied to a large telecommunication network reliability, availability and cost analysis.

Using Markov chain Monte Carlo and dynamic programming for event sequence data

Sequences of events are a common type of data in various scientific and business applications, e.g. telecommunication network management, study of web access logs, biostatistics and epidemiology. A natural approach to modelling event sequences is using time-dependent intensity functions, indicating the expected number of events per time unit. In Bayesian modelling, piecewise constant functions can be utilized to model continuous intensities, if the number of segments is a model parameter. The reversible jump Markov chain Monte Carlo (RJMCMC) methods can be exploited in the data analysis. With very large quantities, these approaches may be too slow. We study dynamic programming algorithms for finding the best fitting piecewise constant intensity function, given a number of pieces. We introduce simple heuristics for pruning the number of the potential change points of the functions. Empirical evidence from trials on real and artificial data sets is provided, showing that the developed methods yield high performance and they can be applied to very large data sets. We also compare the RJMCMC and dynamic programming approaches and show that the results correspond closely. The methods are applied to fault-alarm sequences produced by large telecommunication networks.

Estimating the CPU utilization of a rule-based system

Rule-based software systems have become very common in telecommunications settings, particularly to monitor and control workflow management of large networks. At the same time, shorter deployment cycles are frequently necessary which has led to modifications being made to the rule base, without a full assessment of the impact of these new rules through extensive performance testing.An approach is presented that helps assess the performance of rule-based systems, in terms of its CPU utilization, by using modeling and analysis. A case study is presented applying this approach to a large rule-based system that is used to monitor a very large industrial telecommunications network.

Reliability evaluation of large telecommunication networks

In this paper, we describe an approximation method to evaluate the reliability of large telecommunication networks based on optic fibre and digital cross-connect systems (DCS). The reliability measures are defined as the availability and the expected lost traffic. Their evaluation is decomposed into the rerouting calculation and the probabilistic calculation. The rerouting calculation (restoration from failures) is accomplished by a heuristic method using the K-shortest paths. It is made very rapidly, thanks to a sophisticated data structure. The probabilistic calculation is based on the stratified sampling which results in computational savings of several orders of magnitude and is well suited to very large networks with high reliability components.

Simulations of large telecommunication networks based on probabilistic modeling

We describe a new technique for simulations of large communication networks. This technique is based on a new ap- proach for mobile communication networks modeling by means of point processes and stochastic geometry tools. Simulator ARC de- veloped by the authors and described in the paper uses recent ef- fective geometrical algorithms for computing the topology of the sys- tem model. New algorithms based on stochastic gradient technique and implemented in the simulator allow evaluation of certain perfor- mance characteristics of the system and can be used for optimiza- tion of the system parameters. We analyze the used estimator and give its asymptotic variance. © 1997 SPIE and IS&T.

Repositories for co-operative information systems

Repository technology has become a pervasive part of the software development process. The role played by the repository within the modern software development process is to support a particular software engineering (SE) environment, and to provide an extensive set of services that allows CASE tools to interface with the repository. The next generation of Information Systems (ISs), often referred to as Co-operative Information Systems (CISs), will involve a number of information agents distributed over large computer and telecommunications networks. One of the most prominent problems faced by such CISs is the problem of co-operation and collaboration. It is realized that such problems are analogous to those in software development process addressed by repository technology. This paper presents the experience of introducing repository technology into a CIS. The goal of developing a shareable and reusable central repository is achieved by deploying the object-oriented data model paradigm. This paper also presents a novel way to deal with real-time CISs by separating the services of a repository into two distinct subsets provided by its off-line component and its on-line component. The successful incorporation of repository technology with a real-world CIS application has demonstrated both the feasibility and the benefits of such integration.

Optimizedk-shortest-paths algorithm for facility restoration

The problem of finding shortest paths arises in many contexts; testing restoration algorithms and developing design packages for large telecommunications networks are two cases where the simple task of finding sets of restoration paths can consume up to 95 per cent of the execution time of an application program. This paper presents experimental studies of several well-known shortest-paths algorithms adapted to the task of finding the k-successively-shortest link-disjoint replacement paths for restoration in a telecommunications network with n nodes. The implementations range in complexity from O(kn2) when based on Dijkstra's original method, through several improvements to an efficient implementation of O(kn[v+longn]) complexity, and finally to an O(kn) implementation for the special case of edge-sparse graphs with small integer edge weights. Here v is the maximum degree of a node in the network. Several alternatives were tested during the course of these studies, particularly with a view to minimizing the number of heap updates, These alternatives are possible because we are searching for several paths between a given pair of nodes, rather than just one path between one or more pairs of nodes. Two fairly straightforward changes yield a decrease in execution time, whereas a more complex heap management strategy consumes as much time in the added code as it releases from the main routine. Experimental results confirm the theoretical complexity of q k n log n) and demonstrate a speed-up of nearly an order of magnitude over the simpler O(kn2) implementation in the largest networks tested. The optimized implementation is recommended for planning and operational applications of k-shortest paths rerouting for telecommunications network restoration and restorable network design. If hop counts or small integer link weights can be used to measure distances, then the qkn) implementation is recommended, as typical telecommunications networks are edge-sparse.

A computer approach for reliability evaluation of telecommunication networks with heterogeneous link-capacities

The authors present a computer approach to obtaining a survivability index called capacity related reliability (CRR) in large telecommunication networks where links have different capacities. The method is a two-step approach. The first step deals with composite path enumeration (CPE). A k-composite path is defined as the union of the set of edges in any k simple paths and relates link capacity and network connectivity. The CPE approach is an improvement over the algorithms proposed by the authors earlier (1991). In step two, k-composite paths information is manipulated to generate the CRR. The authors use CAREL (computer aided reliability evaluator) to solve this step. The technique is automated using C on the Encore Multimax System. The results on CRR for three networks with various values of minimum message capacity are presented. An exhaustive technique is used to verify these results. An informal proof of the CPE approach is also included. >

Multi-focus fractal-graph networks

We introduce the notion of multi-focus fractal-graph networks which are used to characterize large dynamic telecommunication, computer and data networks. These networks are synthesized using recently developed concepts of fractal geometry and are characterized by a fractal dimension, more than one central node and a large number of auxiliary nodes. Performance characteristics of these networks are related to their geometrical and fractal descriptors. Several examples, using three general classes of these networks, are developed here based on a modified diffusion-limited aggregation process in which hundreds or thousands of nodes are involved. Network performance of these classes is compared and contrasted.

Practical Experience in Software Engineering with ADA: Building an Operation Guidance; Recovery and Maintenance Planning System

In the development of an operation guidance, recovery and maintenance planning system for a large telecommunication network handling both data and voice the use of commercial standard software has been chosen. A network analysis system, capable to model several thousands of nodes and links together with a decision support system for the operator is being developped in an ADA environment on VAX/VMS machines, data storage is organized around an ORACLE database, and man-machine communication is almost exclusively done in graphics using GKS.It will be shown how the standard packages have been integrated to guarantee both minimum development effort for the project, and fast real time response. Various compatibility problems and their solutions will be discussed, as well as criteria which standard software to choose in which cases.Practical experiences and benefits using ADA in a small team of three to four software engineers both as a design and implementation language combined with rapid prototyping as a development methodology will be presented.

Continuous Models for Capacity Design of Large Packet-Switched Telecommunication Networks

We formulate nonlinear programming models for design of large-scale packet-switched telecommunication networks. In these models, the network’s link capacities and source-destination message routes are chosen simultaneously. Although leased communication lines are available only in discrete units of capacity, public telephone lines with high-speed modems can be used to augment them, thus effectively obtaining fractional equivalents of leased-line capacity. Therefore, our network-design models contain continuous link-capacity variables. These continuous models can be solved for ϵ-optimal solutions, even for networks with hundreds or thousands of nodes. We examine conventional link delay functions used by previous researchers and suggest an alternative class of convex delay functions. Using computer simulation to analyze link delays, we compare the convex delay function to the conventional one. We conclude, for our assumed message-length distribution, that the convex delay function predicts the simulated delays more accurately than the conventional one when flow-capacity ratios larger than or equal to 0.80 are ignored. However, the conventional delay function fits the simulated delays more accurately than the convex one when these high-congestion ratios are considered. Thus, in network-design models in which flow-capacity ratios must be less than 80%, our convex model can be more accurate than the nonconvex conventional one. Computational results show that our models give very good solutions for different size networks with up to 100 nodes. INFORMS Journal on Computing, ISSN 1091-9856, was published as ORSA Journal on Computing from 1989 to 1995 under ISSN 0899-1499.