Message Oriented Middleware

International Journal of Embedded Systems and Applications (IJESA) is a quarterly open access peer-reviewed journal that publishes articles which contribute new results in all areas of the Embedded Systems and applications. The goal of this journal is to bring together researchers and practitioners from academia and industry to focus on understanding Embedded Systems and establishing new collaborations in these areas.

This paper addresses a numerical electromagnetic analysis of the influence of installing passive shield wires "extra ground wires" (EGW) underneath the bottom phase conductor on the lightning shielding performance of 765-kV, 3-phase, double-circuit transmission lines. The method of moment (MOM) is employed to model the whole structure in three dimensions except the lightning channel. The lightning channel is simulated by the well-known transmission-line model (TLM), where the influence of the lightning-channel-generated electric and magnetic fields (EMF) are taken into account. The lightning shielding performance with and without EGW is introduced and discussed, without ac energization and due to three distinct lightning strokes, namely, the negative first, the negative subsequent and the positive strokes. The produced voltages and currents in the phase conductors and ground wires as well as the voltage across the insulators are computed, with and without the EGW, due to different lightning current waveforms, locations and inclination of the lightning channel, and return-stroke velocities. The introduction of such EGW results in a significant improvement of the shielding effectiveness by reducing the lightning-produced voltages and currents in the phase conductors as well as the voltage across the insulators. Accordingly, a much lower transient overvoltages can be expected with less inadvertent outages of the lines, where the probabilities of flashover and back-flashover decrease, and the reliability enhances. Index Terms-Electric and magnetic fields (EMF), extra ground wires (EGWs), insulator voltage, lightning shielding, numerical electromagnetic transient.

The middleware technology used as the foundation of Internet-enabled enterprise systems is becoming increasingly complex. In addition, the various technologies offer a number of standard architectures that can be used by designers as templates to build applications. However, there is little concrete understanding in the software industry on the strengths and weaknesses of competing technologies, and the different trade-offs that various component architectures impose. The SACT Group at CSIRO has qualitatively and quantitatively evaluated a number of commercially available Message-Oriented Middleware (MOM) systems. This paper focuses on the results obtained from the performance evaluation of the IBM's MQSeries V5.2. It presents an overview of the technology, and discusses the metric used in this study for performance measurement The test results related to the sustainable performance of the system using various test configurations are described and their implications discussed.

Software integration is a crucial aspect of collaborative software applications and systems. It enables a number of different software applications, created by different developers, using different programming languages, and even located at different places to work with each other collaboratively to achieve common goals. Nowadays, a number of techniques are available to enable software integration. Messaging is the most prominent technique in this respect. In this paper, two leading open-source messaging brokers, Apache ActiveMQ and Apache Apollo, have been experimentally compared with each other with regard to their messaging capabilities (message sending and receiving throughputs). Both brokers support exchanging messages between heterogeneous and distributed software applications using several messaging mechanisms including Java Message Service (henceforth JMS). A number of experimental test scenarios have been conducted to obtain the comparison results that indicate the one-to-one JMS messaging performance of each broker. Overall performance evaluation and analysis showed that Apache Apollo outperformed Apache ActiveMQ in all test scenarios regarding message sending throughputs. Whereas, Apache ActiveMQ outperformed Apache Apollo in most test scenarios regarding message receiving throughputs. Moreover, the evaluation methodology (test conditions, test scenarios, and test metrics) proposed in this paper has been carefully chosen to be adopted by software developers to evaluate other messaging brokers to determine the acceptable level of messaging capabilities in distributed environments of heterogeneous software applications.

The middleware technology used as the foundation of Internet-enabled enterprise systems is becoming increasingly complex. In addition, the various technologies offer a number of standard architectures that can be used by designers as templates to build applications. However, there is little concrete understanding in the software industry on the strengths and weaknesses of competing technologies, and the different trade-offs that various component architectures impose. The SACT Group at CSIRO has qualitatively and quantitatively evaluated a number of commercially available Message-Oriented Middleware (MOM) systems. This paper focuses on the results obtained from the performance evaluation of the IBM's MQSeries V5.2. It presents an overview of the technology, and discusses the metric used in this study for performance measurement The test results related to the sustainable performance of the system using various test configurations are described and their implications discussed.

This paper describes the Maximum Likely Estimation (MLE) method and the Method of Moments (MOM) for wind speed modeling. The Weibull wind speed distribution models are fitted using the two methods and the wind data from a tall tower in the Midwestern United States, with seasonal wind speed variations also considered in the modeling. It turned out that both methods provide very similar results with comparable accuracy. The Monte Carlo simulation is used for obtaining expected wind energy production using a Weibull sampling technique.

The middleware market represents a sizable segment of the overall Information and Communication Technology market. In 2005, the annual middleware license revenue was reported by Gartner to be in the region of 8.5 billion US Dollars. In this article we address the question whether research had any involvement in the creation of the technology that is being sold in this market? We attempt a scholarly discourse. We present the research method that we have applied to answer this question. We then present a brief introduction into the key middleware concepts that provide the foundation for this market. It would not be feasible to investigate any possible impact that research might have had. Instead we select a few very successful technologies that are representative for the middleware market as a whole and show the existence of impact of research results in the creation of these technologies. We investigate the origins of web services middleware, distributed transaction processing middleware, message oriented middleware, distributed object middleware and remote procedure call systems. For each of these technologies we are able to show ample influence of research and conclude that without the research conducted by PhD students and researchers in university computer science labs at Brown, CMU, Cambridge, Newcastle, MIT, Vrije, and University of Washington as well as research in industrial labs at APM, AT&T Bell Labs, DEC Systems Research, HP Labs, IBM Research and Xerox PARC we would not have middleware technology in its current form. We summarise the article by distilling lessons that can be learnt from this evidenced impact for future technology transfer undertakings.

A wireless sensor network (WSN) consists of a large number of small devices with computational power, wireless communication and sensing capability. These networks have been developed for a wide range of applications, such as habitat monitoring, object tracking, precision agriculture, building monitoring and military systems. Meanwhile, middleware systems have also been proposed in to facilitate both the development of these applications and provide common application services. The development of middleware for sensor networks, however, places new challenges on middleware developers due to the low availability of resources and processing capacity of the sensor nodes. In this context, this paper presents the design and implementation of a middleware for WSN named Mires. Mires incorporates characteristics of message-oriented middleware by allowing applications communicate in a publish/subscribe way. In order to illustrate the proposed middleware, we have also developed an environment-monitoring application and a data aggregation service.

The middleware market represents a sizable segment of the overall Information and Communication Technology market. In 2005, the annual middleware license revenue was reported by Gartner to be in the region of 8.5 billion US Dollars. In this article we address the question whether research had any involvement in the creation of the technology that is being sold in this market? We attempt a scholarly discourse. We present the research method that we have applied to answer this question. We then present a brief introduction into the key middleware concepts that provide the foundation for this market. It would not be feasible to investigate any possible impact that research might have had. Instead we select a few very successful technologies that are representative for the middleware market as a whole and show the existence of impact of research results in the creation of these technologies. We investigate the origins of web services middleware, distributed transaction processing middleware, message oriented middleware, distributed object middleware and remote procedure call systems. For each of these technologies we are able to show ample influence of research and conclude that without the research conducted by PhD students and researchers in university computer science labs at Brown, CMU, Cambridge, Newcastle, MIT, Vrije, and University of Washington as well as research in industrial labs at APM, AT&T Bell Labs, DEC Systems Research, HP Labs, IBM Research and Xerox PARC we would not have middleware technology in its current form. We summarise the article by distilling lessons that can be learnt from this evidenced impact for future technology transfer undertakings.

Narada is a distributed event brokering system designed to run on a large network of cooperating broker nodes. Narada supports heterogeneous client configurations that scale to arbitrary size and incorporates efficient routing algorithms to optimize disseminations to clients. Narada is failure resilient and guarantees delivery in the presence of failures. In this paper we provide an overview of the Narada event brokering system. The paper also describes the Java Message Service compliance process and support for peer-to-peer interactions in Narada. Finally, the paper outlines issues and entry points for supporting Web Services within Narada

We review several aspects of building real-time streaming data Grid applications. Building on general purpose messaging system software (Na-radaBrokering) and generalized collaboration services (GlobalMMCS), we are developing a diverse set of interoperable capabilities. These include dynamic information systems for managing short-lived collaborative service collections ("gaggles"), stream filters to support the integration of Geographical Information Systems services with data analysis applications, streaming video to support collaborative geospatial maps with time-dependent data, and video stream playback and annotation services to enable scientific collaboration.

Initial implementations of Middleware based on standards such as CORBA have concentrated on host and language transparency issues in order to demonstrate interoperability. They have largely adopted a No-Replication approach and have frequently neglected performance-at-scale issues. This has lead to a continuing deployment of either non-scalable Full-Replication approaches or ad-hoc messaging-based Middleware for applications such as Intelligent Networks, WWW applications and Collaborative Virtual Reality. These applications require millions of objects globally distributed across hundreds of hosts and demand a very high throughput of low-latency method invocations. Our main research aim is to be able to reason about the performance of such applications when using scalable Partial-Replication and Object-Oriented approaches to Middleware. Our approach is to capture in a simulator, the behaviour of distributed systems hardware and software components such as networks, hosts, multithreading, caching and RMI mechanisms. We then use the simulator to explore potential design and implemention choices. Our current simulator-driven design, called "MinORB", has been fully implemented and tested. MinORB supports scaleable high-performance by a combination of techniques including weak and application-specified consistency and partial replication using fine-grained proxy caching. Experimental results show that our work compares very favourably with other leading implementations such as OmniORB. Scalability is unparalleled with up to 1,000,000,000 objects per address space, a maximum throughput of 42,000 invocations per second and service times as low as 4 microseconds.

Due to the shift from software-as-a-product (SaaP) to software-as-a-service (SaaS), software components that were developed to run in a single address space must increasingly be accessed remotely across the network. Distribution middleware is frequently used to facilitate this transition. Yet a range of middleware platforms exist, and there are few existing guidelines to help the programmer choose an appropriate middleware platform to achieve desired goals for performance, conciseness, intuitiveness, and reliability. To address this limitation, in this article, we describe a case study of transitioning an Open Service Gateway Initiative (OSGi) service from local to remote access. In our case study, we evaluate five remote versions of this service, constructed using different distribution middleware platforms. These platforms are implemented by widely-used commercial technologies or have been proposed as improvements on the state of the art. In particular, we implemented a service-oriented version of our own Remote Batch Invocation abstraction. We compare and contrast these implementations in terms of their respective performance, conciseness, complexity, and reliability. Our results can help remote service programmers make informed decisions when choosing middleware platforms for their applications. 1

| This paper describes a new control architecture for telerobotics research. The architecture described is object oriented and data driven, and can be distributed over many processors on a wide-area network. The basic capabilities of this testbed have already been demonstrated in tests distributed over four cities. The data distribution techniques of this control architecture are described, as well as details of the current implementation and experimental results. This

The miniaturization of hardware components has lead to the development of Wireless Sensor Networks (WSN) and networked-applications over them. Meanwhile, middleware systems have also been proposed in order to both facilitating the development of these applications and providing common application services. The development of middleware for sensor networks, however, places new challenges to middleware developers due to the low availability of resources and processing capacity of the sensor nodes. In this context, this paper presents a middleware for WSN named Mires. Mires incorporates characteristics of message-oriented middleware by allowing applications communicate in a publish/subscribe way. In order to illustrate the proposed middleware, we implement an aggregation middleware service for an environment-monitoring application.

Software integration is a crucial aspect of collaborative software applications and systems. It enables a number of different software applications, created by different developers, using different programming languages, and even located at different places to work with each other collaboratively to achieve common goals. Nowadays, a number of techniques are available to enable software integration. Messaging is the most prominent technique in this respect. In this paper, two leading open-source messaging brokers, Apache ActiveMQ and Apache Apollo, have been experimentally compared with each other with regard to their messaging capabilities (message sending and receiving throughputs). Both brokers support exchanging messages between heterogeneous and distributed software applications using several messaging mechanisms including Java Message Service (henceforth JMS). A number of experimental test scenarios have been conducted to obtain the comparison results that indicate the one-to-o...

In the last few years, various middleware solutions have been proposed for bridging the gap between the complexity of the applications and the low hardware abstraction in order to program and manage the sensor nodes of the wireless sensor networks. The proposed middleware range from market and data- centric approaches to message oriented middleware. This survey discusses the representative state-of-the-

A lot of research works in different areas have been done on Interoperability frameworks. Each area of research has its own specification and requirements to manage a complex processing request. Interoperability framework is significantly important for utilizing heterogeneous communications and integrations in SOA systems. Various middleware technologies are often used as the communication and integration infrastructure for distributed system to ensure the interoperability. Nevertheless, different types of middleware have raise interoperability issues as well. One of the well known middleware architectures used for heterogeneous systems is Message Oriented Middleware (MOM). MOM is known as common attach technology for heterogeneous, distributed and loosely coupled software system. In this paper we explore and analyze studies related to cross-platform in communication and integration. In the end, we have proposed agent-based MOM interoperability framework and Ontology mapping conceptual model which is the key model to do message mapping for different applications in SOA system.

The Weibull distribution has been found to be a suitable fit for the empirical distribution of the wind speed measurement samples. We discuss the application of the Maximum Likelihood Estimation (MLE) method and the Method of Moments (MOM) for fitting the 2-parameter Weibull distribution to wind speed measurements. We also prove that both the MLE and MOM yields unique parameter estimates.

Localization is one of the fundamental prob-lems in mobile robot navigation. In this paper a study is presented on a new methodology aimed at localizing a mobile robot in indoor and outdoor environments using active markers and commer-cial off-the-shelf webcams. The marker detection system is based on the dif-ference of working frequencies of the shutter of a webcam and of

SAURON (Surveillance AUtonomous Robots Over Network) is a research project focused on the use of autonomous patrolling robots for surveillance purposes. This paper presents the structure of SAURON localization module AMIRoLoS (Active Marker Internet-based Robot Localization System). It provides on demand the robot position in indoor and outdoor environments using active markers and commercial off-theshelf web-cams. The system has a client-server architecture, and is now part of a message-oriented middleware that is under development at the University of Brescia. The functionality of the localization module has been demonstrated with real-world experiments.

This paper studies, in detail, a variety of formulations for the hybrid finite-element and boundary-integral (FE-BI) method for three-dimensional (3-D) electromagnetic scattering by inhomogeneous objects. It is shown that the efficiency and accuracy of the FE-BI method depends highly on the formulation and discretization of the boundary-integral equation (BIE) used.

In the last few years, various middleware solutions have been proposed for bridging the gap between the complexity of the applications and the low hardware abstraction in order to program and manage the sensor nodes of the wireless sensor networks. The proposed middleware range from market and datacentric approaches to message oriented middleware. This survey discusses the representative state-of-theart virtual machine (VM) class of middleware for WSNs highlighting the state of the research.

SIMD extensions are the most common technique used in current processors for multimedia computing. In order to obtain more performance for emerging applications SIMD extensions need to be scaled. In this paper we perform a scalability analysis of SIMD extensions for multimedia applications. Scaling a 1dimensional extension, like Intel MMX, was compared to scaling a 2-dimensional (matrix) extension. Evaluations have demonstrated that the 2-d architecture is able to use more parallel hardware than the 1-d extension. Speed-ups over a 2-way superscalar processor with MMX-like extension go up to 4X for kernels and up to 3.3X for complete applications and the matrix architecture can deliver, in some cases, more performance with simpler processor configurations. The experiments also show that the scaled matrix architecture is reaching the limits of the DLP available in the internal loops of common multimedia kernels.

Web Services hold the promise of a standards-based platform for automating the integration of applications over diverse networks, operating systems and programming languages. Reliable messaging is critical in this context; many enterprise systems require a messaging infrastructure that guarantees message delivery even in the presence of software and network failures. Using existing message-oriented middleware (MOM) for reliable Web services messaging seems natural. However, a variety of implementation challenges, including the support for specific reliable Web services messaging protocols, must be addressed. In this paper, we discuss the options for and implications of employing MOM to implement reliable messaging for Web services. In doing so, we contribute to the understanding of reliability for Web services in general.

This paper presents results of extensive computational experiments in which evolutionary multiobjective algorithms were used to find Pareto-optimal solutions to a complex structural design problem. In particular, Strength-Pareto Evolutionary Algorithm 2 (SPEA2) was combined with a mathematical programming method to find optimal designs of steel structural systems in tall buildings with respect to two objectives (both minimized): the total weight and the maximum horizontal displacement of a tall building. SPEA2 was employed to determine Pareto-optimal topologies of structural members (topology optimization) whose cross-sections were subsequently optimized by the mathematical programming method (sizing optimization). The paper also presents the shape of the Pareto front in this two-dimensional objective space and discusses its dependence on the building's aspect ratio. The results reported provide both qualitative and quantitative knowledge regarding the relationship between the two objectives. They also show the trade-offs involved in the process of conceptual and detailed design of complex structural systems in tall buildings.

This paper presents results of extensive computational experiments in which evolutionary multiobjective algorithms were used to find Pareto-optimal solutions to a complex structural design problem. In particular, Strength-Pareto Evolutionary Algorithm 2 (SPEA2) was combined with a mathematical programming method to find optimal designs of steel structural systems in tall buildings with respect to two objectives (both minimized): the total weight and the maximum horizontal displacement of a tall building. SPEA2 was employed to determine Pareto-optimal topologies of structural members (topology optimization) whose cross-sections were subsequently optimized by the mathematical programming method (sizing optimization). The paper also presents the shape of the Pareto front in this two-dimensional objective space and discusses its dependence on the building's aspect ratio. The results reported provide both qualitative and quantitative knowledge regarding the relationship between the two objectives. They also show the trade-offs involved in the process of conceptual and detailed design of complex structural systems in tall buildings.

This paper presents results of extensive computational experiments in which evolutionary multiobjective algorithms were used to find Pareto-optimal solutions to a complex structural design problem. In particular, Strength-Pareto Evolutionary Algorithm 2 (SPEA2) was combined with a mathematical programming method to find optimal designs of steel structural systems in tall buildings with respect to two objectives (both minimized): the total weight and the maximum horizontal displacement of a tall building. SPEA2 was employed to determine Pareto-optimal topologies of structural members (topology optimization) whose cross-sections were subsequently optimized by the mathematical programming method (sizing optimization). The paper also presents the shape of the Pareto front in this two-dimensional objective space and discusses its dependence on the building's aspect ratio. The results reported provide both qualitative and quantitative knowledge regarding the relationship between the two objectives. They also show the trade-offs involved in the process of conceptual and detailed design of complex structural systems in tall buildings.

A mixed (scalar and vector) potential surface integral equation formulation, developed for microstrip antennas, is employed in conjunction with the method of moments to predict the radiated emission from arbitrarily shaped printed circuit traces. Computed currents and radiated fields for a typical trace configuration in the form of a rectangular loop loaded by low- or high-impedance lumped loads indicate good agreement with transmission line theory and/or elementary loop antenna analysis, when the trace size is electrically small. Computed results are presented to highlight the radiation and coupling due to common-mode currents

A model for mutual impedance calculation in probe fed conformal cylindrical microstrip antenna arrays, covered by a protection layer, is presented. The model is based on the Green's function for multilayered cylindrical structures calculated in the Fourier domain. The integral equations for unknown current distributions on the microstrip elements are solved by the method of moments (MOM). As an application, the mutual impedance between two wraparound antennas is calculated

The TJ-II remote participation system (RPS) is focused on providing remote access to elements that depend exclusively on characteristics of the TJ-II environment: data acquisition, diagnostics control systems and TJ-II operation tracking. Four key points were taken into account prior to starting the software design: access security, software execution platforms, software maintenance and distribution and delivery of operation events. The first, access security, was addressed by means of a distributed authentication and authorization system, PAPI. Regarding the other points, the development was based on the use of web servers (due to their standard character, flexibility and scalability) and Java technologies (due to their open nature, security properties and technological maturity). Software deployment was prepared to make use of the Java Network Launching Protocol (JNLP). On-line message distribution was planned according to a message oriented middleware. At present, the TJ-II RPS manages over 1000 digitization channels and 20 diagnostic control systems. The TJ-II RPS architecture is flexible, scalable and powerful enough to be applied to distributed environments and, in particular, it could be used in the ITER environment.

Diversity in distributed applications leads to diversity in distribution models, and hence in middleware. However, large systems may need different types of middleware and interoperability between them, requiring "Middleware to Middleware" architectures. We have introduced the schizophrenic middleware concept as a general solution for interoperability between distribution models. PolyORB, our implementation of a schizophrenic middleware, demonstrates full interoperability between CORBA, SOAP, and the Ada 95 Distributed System Annex (DSA). In this paper, we present an assessment of the usability of our platform to implement Message Oriented Middleware (MOM). We then study MOM and ORB interoperability, from both an architectural and a functional point of view, and finally discuss benefits provided by our architecture to implement middleware.

This paper discusses the applicability of a hybrid method which combines the Method of Moments (MOM) and the multiconductor transmission line (MTL) equations on modern day PCB-layout. A necessary component of the developed hybrid method is the distinction of the layout structures into structures which can be handled by MTL, structures which must be calculated by MOM and the detection of coupling paths. The developed distinction algorithm is based on appropriate rules and the estimation of computation error due to ignoring coupling paths. The coupling between structures described by the two methods is taken into account by an iterative algorithm and the help of an integral equation for the electrical field strength. The comparison of measurements with results of the hybrid method exposes the applicability of the developed hybrid method.

The interior resonance problem that can occur when using a hybrid finite-element method/method of moments (FEM/MoM) method to model electromagnetic scattering problems is investigated. Calculations of the bistatic radar cross section of a coated dielectric sphere are presented using different formulations, solution approaches, and solvers. The solutions using the electric-field integral equation have significant errors near an interior resonance frequency. When the combined-field integral equation is employed, satisfactory solutions can be obtained that do not depend on the particular solution approach or solver.

JMS is an API specification that defines a standard way for Java applications to access messaging services. All JMS products promise good performance and to properly support the QoS attributes specified in the standard, making it hard to choose between them. Customers who want to determine which JMS product best meets their requirements need a simple, effective and fair methodology for evaluating and comparing competing implementations. This paper presents an empirical methodology for evaluating the QoS implementation of a JMS product. We present a number of test scenarios and define metrics for measuring performance and message persistence. We then illustrate this methodology by using it to evaluate two leading JMS products. Our evaluation results show differences between these products in terms of their overall performance and the impact of various QoS attributes. The case study demonstrates that our empirical methodology is an effective and practical way to test the performance of JMS and other messaging systems.

Our world is becoming increasingly heterogeneous, decentralized and distributed, but the software that is supposed to work in this world, usually, is not. TSpaces is a communication package whose purpose is to alleviate the problems of hooking together disparate distributed systems. TSpaces is a global communication middleware component that incorporates database features, such as transactions, persistent data,¯exible queries and XML support. TSpaces is an excellent tool for building distributed applications, since it provides an asynchronous and anonymous link between multiple clients or services. The communication link provided by TSpaces gives application builders the advantage of ignoring some of the harder aspects of multi-client synchronization, such as tracking names (and addresses) of all active clients, communication line status, and conversation status. For many dierent types of applications, the loose synchronization provided by TSpaces works extremely well. This paper relates our experiences in building distributed systems with TSpaces as the central communication component. Ó

In the last few years, numerous multimedia archives have made extensive use of digitized storage and annotation technologies. Still, the development of single points of access, providing common and uniform access to their data, despite the efforts and accomplishments of standardization organizations, has remained an open issue as it involves the integration of various large-scale heterogeneous and heterolingual systems. This paper describes a mediator system that achieves architectural integration through an extended three-tier architecture and content integration through semantic modeling. The described system has successfully integrated five multimedia archives, quite different in nature and content from each other, while also providing easy and scalable inclusion of more archives in the future.

UNU-IIST is jointly funded by the government of Macao and the governments of the People's Republic of China and Portugal through a contribution to the UNU Endowment Fund. As well as providing two thirds of the endowment fund, the Macao authorities also supply UNU-IIST with its office premises and furniture and subsidise fellow accommodation.

We review several aspects of building real-time streaming data Grid applications. Building on general purpose messaging system software (Na-radaBrokering) and generalized collaboration services (GlobalMMCS), we are developing a diverse set of interoperable capabilities. These include dynamic information systems for managing short-lived collaborative service collections ("gaggles"), stream filters to support the integration of Geographical Information Systems services with data analysis applications, streaming video to support collaborative geospatial maps with time-dependent data, and video stream playback and annotation services to enable scientific collaboration.

Supervisory processes are fundamental when running data center operations striving for fault resilience: any downtime can directly affect the business's income and definitely its reputation. Current monitoring tools rely on experts to configure constant thresholds on single streams, which is not appropriated for dynamic systems and insufficient to capture complex patterns. We present HOLMES, built to support data center experts to anticipate failures with a solution that combines Event Driven Architecture, Complex Event Processing and an unsupervised machine learning algorithm. Based on rules created by the users, the system continuously checks for known problems. Meanwhile, for the unknown ones, we leverage the CEP engine for aggregating and joining streams of real-time data to feed normalized input to FRAHST, our machine learning algorithm that detects anomalous patterns across multivariate numerical streams. We describe how the UI module also operates within the publish/subscribe paradigm to enhance situational awareness. The system had very well acceptance and was successfully implemented at one of the largest Internet Service Providers in South America.

Mutual impedance between flush-mounted antennas on convex surfaces has been traditionally computed at high frequencies using the uniform theory of diffraction (UTD) and other high-frequency asymptotic solutions. Motivated by a recent study, the limits of applicability of the existing asymptotic techniques to the calculation of input (or self-) impedance are investigated here. It is shown analytically that UTD and one other asymptotic formulation, in the close vicinity of a source on a perfectly electrically conducting (PEC) circular cylinder, for negligible local surface curvatures, are algebraically identical. For the canonical geometry of an axial magnetic current element on a PEC circular cylinder, it is shown that the additional paraxial correction term in the UTD formulation vanishes in the high-frequency planar limit. Numerical comparisons against rigorous method of moments (MoM) solutions show that the reduced-planar forms are remarkably accurate for source-to-observer separations, , where 0 02 0 08 , and slightly off the axial direction.

Localization is one of the fundamental prob-lems in mobile robot navigation. In this paper a study is presented on a new methodology aimed at localizing a mobile robot in indoor and outdoor environments using active markers and commer-cial off-the-shelf webcams. The marker detection system is based on the dif-ference of working frequencies of the shutter of a webcam and of

In this paper we propose the main guidelines of a toolkit designed to allow the several different electronic devices (CPUs, microcontrollers, sensor DSPs, etc.) that compose a mobile robot and its environment to cooperate as members of a community. This idea would allow an easy modularization of complex systems that integrate robots and distributed sensors, taking an effective advantage of the newest data processing and communication technologies. The availability of many computing-capable sensing and actuating devices and of broadband communication channels allows us to find new ways of implementing physically distributed systems that can be used in the control of autonomous robots. Our research is aimed at creating an efficient and reliable layered middleware in the hardware-software structure, in order to allow each device to interact in a transparent way with all the others, on the same machine or elsewhere.