Industrial multimedia put into practice

Recent developments in the factory floor technologies together with the widespread use of TCP/IP and the Internet are increasing the eagerness to support a new wide class of devices and applications, such as industrial multimedia applications, in factory floor networks. This paper presents how this new field of applications can be put into practice, via a manufacturing cell field trial being implemented. This manufacturing automation field trial involves the use of traditional distributed computer control systems and 'factory-floor-oriented' multimedia (e.g. voice, video) application services.

Industrial multimedia over factory-floor networks

In this paper we describe a real-time industrial communication network able to support both controlrelated and multimedia traffic. The industrial communication network is based on the PROFIBUS standard, with multimedia capabilities being provided by an adequate integration of TCP/IP protocols into the PROFIBUS stack. From the operational point of view the integration of TCP/IP into PROFIBUS is by itself a challenge, since the master-slave nature of the PROFIBUS MAC makes complex the implementation of the symmetry inherent to IP communications. From the timeliness point of view the challenge is two folded. On one hand the multimedia traffic should not interfere with the timing requirements of the "native" control-related PROFIBUS traffic (typically hard real-time). On the other hand multimedia traffic requires certain levels of quality-of-service to be attained. In this paper we provide a methodology that enables fulfilling the timing requirements for both types of traffic in these real-time industrial LAN. Moreover, we describe suitable algorithms for the scheduling support of concurrent multimedia streams.

A high performance wireless fieldbus in industrial multimedia-related environment

This paper summarises the most important solutions that have emerged from the work carried out by our team within the framework of the EU (IST-1999-11316) project RFieldbus - High Performance Wireless Fieldbus in Industrial Multimedia-Related Environment. Within this project, Profibus was chosen as the fieldbus platform. Essentially, extensions to the current Profibus standard are being developed in order to provide Profibus with wireless, mobility and industrialmultimedia capabilities. In fact, providing these extensions means fulfilling strong requirements, namely to encompass the communication between wired (currently available) and wireless/mobile devices and to support real-time control traffic and multimedia traffic in the same network.

CIDER - envisaging a COTS communication infrastructure for evolutionary dependable real-time systems

It is foreseen that future dependable real-time systems will also have to meet flexibility, adaptability and reconfigurability requirements. Considering the distributed nature of these computing systems, a communication infrastructure that permits to fulfil all those requirements is thus of major importance. Although Ethernet has been used primarily as an information network, there is a strong belief that some very recent technological advances will enable its use in dependable applications with real-time requirements. Indeed, several recently standardised mechanisms associated with Switched-Ethernet seem to be promising to enable communication infrastructures to support hard real-time, reliability and flexible distributed applications. This paper describes the motivation and the work being developed within the CIDER (Communication Infrastructure for Dependable Evolvable Real-Time Systems) project, which envisages the use of COTS Ethernet as an enabling technology for future dependable real-time systems. It is foreseen that the CIDER approach will constitute a relevant stream of research since it will bring together cutting edge research in the field of real-time and dependable distributed systems and the industrial eagerness to expand Ethernet responsabilities to support dependable real-time applications.

Automação industrial. Uma perspetiva de terreno!

De que é que falamos quando nos referimos a AUTOMAÇÃO? - Estamos no âmbito da engenharia eletrotécnica, da mecânica, da eletrónica, da programação, das comunicações, da instrumentação, da pneumática, ….? Na realidade referimo-nos a um pouco disto tudo - a automação será possivelmente a área de engenharia mais pluridisciplinar e integradora de tecnologia. Quererá isto dizer que se trata de uma atividade de Engenharia complexa e densa? - Sim e não! - Vejamos; é vasta e densa porque o seu exercício obriga ao conhecimento de um alargado e diversificado leque de tecnologias mas, a sua base teórica, ou se quisermos os seus “algoritmos”, são bastante simples; baseiam-se em lógica e em sequências temporais. Que competências serão então necessárias para se exercer Automação? - Um conhecimento transversal de engenharia, com particular foco na Engenharia Eletrotécnica e uma boa experiência de terreno. Partindo desta constatação este artigo tem a intenção de abordar a automação de um ponto de vista eminentemente prático e aplicado.

Online intra-task device scheduling for hard real-time systems

A large part of power dissipation in a system is generated by I/O devices. Increasingly these devices provide power saving mechanisms, inter alia to enhance battery life. While I/O device scheduling has been studied in the past for realtime systems, the use of energy resources by these scheduling algorithms may be improved. These approaches are crafted considering a very large overhead of device transitions. Technology enhancements have allowed the hardware vendors to reduce the device transition overhead and energy consumption. We propose an intra-task device scheduling algorithm for real time systems that allows to shut-down devices while ensuring system schedulability. Our results show an energy gain of up to 90% when compared to the techniques proposed in the state-of-the-art.

Improving quality-of-service in wireless sensor networks by mitigating “Hidden-Node Collisions”

Wireless sensor networks (WSNs) emerge as underlying infrastructures for new classes of large-scale networked embedded systems. However, WSNs system designers must fulfill the quality-of-service (QoS) requirements imposed by the applications (and users). Very harsh and dynamic physical environments and extremely limited energy/computing/memory/communication node resources are major obstacles for satisfying QoS metrics such as reliability, timeliness, and system lifetime. The limited communication range of WSN nodes, link asymmetry, and the characteristics of the physical environment lead to a major source of QoS degradation in WSNs-the ldquohidden node problem.rdquo In wireless contention-based medium access control (MAC) protocols, when two nodes that are not visible to each other transmit to a third node that is visible to the former, there will be a collision-called hidden-node or blind collision. This problem greatly impacts network throughput, energy-efficiency and message transfer delays, and the problem dramatically increases with the number of nodes. This paper proposes H-NAMe, a very simple yet extremely efficient hidden-node avoidance mechanism for WSNs. H-NAMe relies on a grouping strategy that splits each cluster of a WSN into disjoint groups of non-hidden nodes that scales to multiple clusters via a cluster grouping strategy that guarantees no interference between overlapping clusters. Importantly, H-NAMe is instantiated in IEEE 802.15.4/ZigBee, which currently are the most widespread communication technologies for WSNs, with only minor add-ons and ensuring backward compatibility with their protocols standards. H-NAMe was implemented and exhaustively tested using an experimental test-bed based on ldquooff-the-shelfrdquo technology, showing that it increases network throughput and transmission success probability up to twice the values obtained without H-NAMe. H-NAMe effectiveness was also demonstrated in a target tracking application with mobile robots - over a WSN deployment.

Operational modal monitoring of ancient structures using wireless technology

Operational Modal Analysis is currently applied in structural dynamic monitoring studies using conventional wired based sensors and data acquisition platforms. This approach, however, becomes inadequate in cases where the tests are performed in ancient structures with esthetic concerns or in others, where the use of wires greatly impacts the monitoring system cost and creates difficulties in the maintenance and deployment of data acquisition platforms. In these cases, the use of sensor platforms based on wireless and MEMS would clearly benefit these applications. This work presents a first attempt to apply this wireless technology to the structural monitoring of historical masonry constructions in the context of operational modal analysis. Commercial WSN platforms were used to study one laboratory specimen and one of the structural elements of a XV century building in Portugal. Results showed that in comparison to the conventional wired sensors, wireless platforms have poor performance in respect to the acceleration time series recorded and the detection of modal shapes. However, for frequency detection issues, reliable results were obtained, especially when random excitation was used as noise source.

Wind energy technology

Electricity is regarded as one of the indispensable means to growth of any country’s economy. This source of power is the heartbeat of everything from the huge metropolitans, industries, worldwide computer networks and our global communication systems down to our homes. Electrical energy is the lifeline for any economic and societal development of a region or country. It is central to develop countries for maintaining acquired life styles and essential to developing countries for industrialisation and escaping poverty.

Bridge architecture to interconnect hybrid wired/wireless PROFIBUS networks

The integration of wired and wireless technologies in modern manufacturing plants is now of paramount importance for the competitiveness of any industry. Being PROFIBUS the most widely used technology in use for industrial communications, several solutions have been proposed to provide PROFIBUS networks with wireless communications. One of them, the bridge-based hybrid wired/wireless PROFIBUS network approach, proposes an architecture in which the Intermediate Systems operate at Data Link Layer level, as bridges. In this paper, we propose an architecture for the implementation of such a bridge and the required protocols to handle communication between stations in different domains and the mobility of wireless stations.

Bertrand model under incomplete information

We consider a Bertrand duopoly model with unknown costs. The firms' aim is to choose the price of its product according to the well-known concept of Bayesian Nash equilibrium. The chooses are made simultaneously by both firms. In this paper, we suppose that each firm has two different technologies, and uses one of them according to a certain probability distribution. The use of either one or the other technology affects the unitary production cost. We show that this game has exactly one Bayesian Nash equilibrium. We analyse the advantages, for firms and for consumers, of using the technology with highest production cost versus the one with cheapest production cost. We prove that the expected profit of each firm increases with the variance of its production costs. We also show that the expected price of each good increases with both expected production costs, being the effect of the expected production costs of the rival dominated by the effect of the own expected production costs.

Addressing software impact in the design of remote laboratories

Remote Laboratories or WebLabs constitute a first-order didactic resource in engineering faculties. However, in many cases, they lack a proper software design, both in the client and server side, which degrades their quality and academic usefulness. This paper presents the main characteristics of a Remote Laboratory, analyzes the software technologies to implement the client and server sides in a WebLab, and correlates these technologies with the characteristics to facilitate the selection of a technology to implement a WebLab. The results obtained suggest the adoption of a Service Oriented Laboratory Architecture-based approach for the design of future Remote Laboratories so that client-agnostic Remote Laboratories and Remote Laboratory composition are enabled. The experience with the real Remote Laboratory, WebLab-Deusto, is also presented.

Integração da análise energética na gestão Industrial de uma refinaria de açúcar

Mestrado em Engenharia Química - Optimização Energética na Industria Química

Licensing in an international triopoly

We study the effects of entry of two foreign firms on domestic welfare in the presence of licensing, when the incumbent is technologically superior to the entrants. We consider two different situations: (i) the cost-reducing innovation is licensed to both entrants; (ii) the cost- reducing innovation is licensed to just one of the entrants. We analyse three kind of license: (lump- sum) fixed-fee; (per-unit) royalty; and two-part tariff, that is a combination of a fixed-fee and a royalty. We prove that a two part tariff is never an optimal licensing scheme for the incumbent. Moreover, (i) when the technology is licensed to the two entrants, the optimal contract consists of a licensing with only output royalty; and (ii) when the technology is licensed to just one of the entrants, the optimal contract consists of a licensing with only a fixed-fee.