Current Issue : October - December Volume : 2015 Issue Number : 4 Articles : 4 Articles
The inclusion of embedded sensors into a networked system provides useful\ninformation for many applications. A Distributed Control System (DCS) is one of the\nclearest examples where processing and communications are constrained by the client�s\nrequirements and the capacity of the system. An embedded sensor with advanced\nprocessing and communications capabilities supplies high level information, abstracting\nfrom the data acquisition process and objects recognition mechanisms. The implementation\nof an embedded sensor/actuator as a Smart Resource permits clients to access sensor\ninformation through distributed network services. Smart resources can offer sensor services\nas well as computing, communications and peripheral access by implementing a self-aware\nbased adaptation mechanism which adapts the execution profile to the context. On the\nother hand, information integrity must be ensured when computing processes are\ndynamically adapted. Therefore, the processing must be adapted to perform tasks in a\ncertain lapse of time but always ensuring a minimum process quality. In the same way,\ncommunications must try to reduce the data traffic without excluding relevant information.\nThe main objective of the paper is to present a dynamic configuration mechanism to adapt\nthe sensor processing and communication to the client�s requirements in the DCS. This\npaper describes an implementation of a smart resource based on a Red, Green, Blue, and\nDepth (RGBD) sensor in order to test the dynamic configuration mechanism presented....
This paper deals with the formal modeling and verification of reconfigurable and energy-efficient manufacturing systems (REMSs)\nthat are considered as reconfigurable discrete event control systems. A REMS not only allows global reconfigurations for switching\nthe system from one configuration to another, but also allows local reconfigurations on components for saving energy when the\nsystem is in a particular configuration. In addition, the unreconfigured components of such a system should continue running\nduring any reconfiguration. As a result, during a system reconfiguration, the system may have several possible paths and may fail to\nmeet control requirements if concurrent reconfiguration events and normal events are not controlled. To guarantee the safety and\ncorrectness of such complex systems, formal verification is of great importance during a system design stage. This paper extends\nthe formalism reconfigurable timed net condition/event systems (R-TNCESs) in order to model all possible dynamic behavior in\nsuch systems. After that, the designed system based on extended R-TNCESs is verified with the help of a software tool SESA for\nfunctional, temporal, and energy-efficient properties. This paper is illustrated by an automatic assembly system....
In this work, we study and analyze the performance of physical layer algorithms for adaptive multiple input-multiple\noutput orthogonal frequency-division multiplexing (MIMO-OFDM) wireless systems that employ a new class of\nadaptive antenna systems known as reconfigurable antennas. These antennas are capable of adaptively modifying\ntheir radiation characteristics and thus leverage pattern diversity to affect how the transmitter and receiver perceive\nthe wireless channel. We propose a low complexity spatial adaptive modulation and coding (AMC) algorithm that\nuses the advantages of pattern reconfigurable antennas in concert with link adaptation to improve MIMO-OFDM link\nthroughput. The algorithm operates in two main stages; first, it searches for the antenna configuration that yields the\nhighest post processing signal-to-noise ratio (ppSNR) and, then, applies AMC to improve spectral efficiency. The\nperformance of the proposed scheme is experimentally evaluated for a 2 Ã?â?? 2 MIMO-OFDM wireless system in an\nindoor environment....
We show the advantages of modular and hierarchical design in obtaining fault-tolerant software. Modularity enables the\nidentification of faulty software units simplifying key operations, like software removal and replacement. We describe three\napproaches to repair faulty software based on replication, namely, Passive Replication, N-Version Replication, and Active\nReplication, based on modular components. We show that the key construct to represent these tactics is the ability to make ad\nhoc changes in software topologies. We consider hierarchical mobility as a useful operation to introduce new software units for\nreplacing faulty ones. For illustration purposes,we use connecton, a hierarchical,modular, and self-modifying software specification\nformalism, and its implementation in the Desmos framework....
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