Search results for " computing"
showing 10 items of 2075 documents
An Object-Oriented Approach to Discrete-Event Simulation Applied to Underground Railway Systems
1999
This paper describes the implementation of an object-oriented simulator that supports the determination of timetables and the design of on-line control policies for underground rail way systems. The simulator has been developed on the basis of a new approach to object- oriented modelling. Such an approach has been used to design a development tool that supports the generation of simulation codes and is able to automatically define the skeleton of a code.
Cost benefits of flexible hybrid cloud storage : Mitigating volume variation with shorter acquisition cycle
2016
The hybrid cloud storage is investigated as a case of concurrent sourcing.The paper introduces an analytical model for hybrid cloud storage costs.We study the role of acquisition cycle and volume variation in hybrid cloud costs.Shortening the reassessment interval reduces the volume non-stationarity.Shortening the reassessment interval reduces the total hybrid costs. Hybrid cloud storage combines cost-effective but inflexible private storage along with flexible but premium-priced public cloud storage. As a form of concurrent sourcing, it offers flexibility and cost benefits to organizations by allowing them to operate at a cost-optimal scale and scope under demand volume uncertainty. Howeve…
Design Patterns and Organisational Memory in Mobile Application Development
2005
Mobile application development is a challenging task for the software companies due to complicated technological and business environments. Patterns have been recognised to be a valuable tool in software development, for they allow design experiences and solutions to be documented systematically and facilitate the communication of design issues. Patterns can be seen as a part of organisational memory, a means to preserve the design knowledge and enable its reuse in later products and projects. In this paper we study how the design patterns can support organisational memory in mobile application design. We present the utilisation of patterns as a dynamic process and analyse their relationshi…
Kalman filtering applied to Profibus-DP systems. Multirate control systems with delayed signals
2008
In networked control systems several devices (controllers, sensors and actuators) share a common communication resource. This feature can introduce variable and even random delays when those devices try to transmit information through the shared medium. The limited bandwidth capabilities of the transmission medium also can restrict the freedom to set the sampling periods in the control loop. An attempt to reduce the significance of the signal delays and save to some bandwidth can be based on high values of sampling periods. Usually this solution has remarkable effects in the system performance because with higher sampling periods closed loop response capabilities are decreased. This paper p…
Multimedia applications in industrial networks: integration of image processing in profibus
2003
This paper analyzes the transmission of images through Profibus for applications concerned with the processing of images integrated in control systems, by means of a detailed study of two real cases with different bandwidth requirements. We analyze the special features of an artificial vision system making use of Profibus as a transport system, the scheduling of the traffic in order to guarantee the delivery of the images and the control traffic before their deadlines, the protocol used, and the compression techniques usable in this kind of system, which enable us to reduce the necessary bandwidth for the applications without degrading the operation of the image processing application. We p…
Optimizing the MAC Protocol in Localization Systems Based on IEEE 802.15.4 Networks
2017
Radio frequency signals are commonly used in the development of indoor localization systems. The infrastructure of these systems includes some beacons placed at known positions that exchange radio packets with users to be located. When the system is implemented using wireless sensor networks, the wireless transceivers integrated in the network motes are usually based on the IEEE 802.15.4 standard. But, the CSMA-CA, which is the basis for the medium access protocols in this category of communication systems, is not suitable when several users want to exchange bursts of radio packets with the same beacon to acquire the radio signal strength indicator (RSSI) values needed in the location proce…
Power Consumption Analysis of Operating Systems for Wireless Sensor Networks
2010
In this paper four wireless sensor network operating systems are compared in terms of power consumption. The analysis takes into account the most common operating systems-TinyOS v1.0, TinyOS v2.0, Mantis and Contiki-running on Tmote Sky and MICAz devices. With the objective of ensuring a fair evaluation, a benchmark composed of four applications has been developed, covering the most typical tasks that a Wireless Sensor Network performs. The results show the instant and average current consumption of the devices during the execution of these applications. The experimental measurements provide a good insight into the power mode in which the device components are running at every moment, and t…
Automated inventory management and security surveillance system using image processing techniques
2010
Efficient inventory management and allocation of cargo space is an imperative parameter in the industry today. In this paper we propose an algorithm to automate complete inventory unit with the aid of image processing and artificial intelligence algorithms. These algorithms work on the data acquired through image processing. This data then integrates with the Artificial Intelligence algorithm which in turn takes inputs from the sensors present on the robot. These sensors help in precise localization of the robot. The path planning algorithm takes input from virtual map buffer which is present in the CPU memory. This buffer in accordance with the sensor data and Image Processing data generat…
A distributed architecture for autonomous navigation of robots
2002
The paper shows a distributed architecture for autonomous robot navigation. The architecture is based on three modules that are implemented on separate and interacting agents: the target recognizer, the obsta90cle evaluator and the planner. An adaptive genetic algorithm has been studied to identify mechanisms for reaching the target and for manipulating the 2-directions of the robot; the distributed architecture has been embedded in the DAISY (Distributed Architecture for Intelligent System). Experiments have been carried out using a LEGO intelligent brick.
Overgrid: A Fully Distributed Demand Response Architecture Based on Overlay Networks
2017
In this paper, we present Overgrid, a fully distributed peer-to-peer (P2P) architecture designed to automatically control and implement distributed demand response (DR) schemes in a community of smart buildings with energy generation and storage capabilities. As overlay networks in communications establish logical links between peers regardless of the physical topology of the network, the Overgrid is able to apply some power balance criteria to its system of buildings, as they belong to a virtual microgrid, regardless of their physical location. We exploit an innovative distributed algorithm, called flow updating, for monitoring the power consumption of the buildings and the number of nodes…