15 resultados para opportunistic routing
em Universidad Politécnica de Madrid
Resumo:
Many context-aware applications rely on the knowledge of the position of the user and the surrounding objects to provide advanced, personalized and real-time services. In wide-area deployments, a routing protocol is needed to collect the location information from distant nodes. In this paper, we propose a new source-initiated (on demand) routing protocol for location-aware applications in IEEE 802.15.4 wireless sensor networks. This protocol uses a low power MAC layer to maximize the lifetime of the network while maintaining the communication delay to a low value. Its performance is assessed through experimental tests that show a good trade-off between power consumption and time delay in the localization of a mobile device.
Resumo:
This paper describes the basic tools to work with wireless sensors. TinyOShas a componentbased architecture which enables rapid innovation and implementation while minimizing code size as required by the severe memory constraints inherent in sensor networks. TinyOS's component library includes network protocols, distributed services, sensor drivers, and data acquisition tools ? all of which can be used asia or be further refined for a custom application. TinyOS was originally developed as a research project at the University of California Berkeley, but has since grown to have an international community of developers and users. Some algorithms concerning packet routing are shown. Incar entertainment systems can be based on wireless sensors in order to obtain information from Internet, but routing protocols must be implemented in order to avoid bottleneck problems. Ant Colony algorithms are really useful in such cases, therefore they can be embedded into the sensors to perform such routing task.
Resumo:
There are many studies related with airport surface routing algorithms, based on different approaches and with different evaluation methods and metrics. So, the need of performing a balanced analysis and comparison using a common framework is evident. This paper presents an implementation of an evaluation tool for airport surface routing algorithms. The routing evaluation tool presented here is based in three basic pillars composed by the airport model, the model and generation of traffic and a comprehensive figure of merit function. The paper includes some example evaluations performed over Barajas Airport with representative traffic samples using several simple routing methods.
Resumo:
We show a cluster based routing protocol in order to improve the convergence of the clusters and of the network it is proposed to use a backup cluster head. The use of a event discrete simulator is used for the implementation and the simulation of a hierarchical routing protocol called the Backup Cluster Head Protocol (BCHP). Finally it is shown that the BCHP protocol improves the convergence and availability of the network through a comparative analysis with the Ad Hoc On Demand Distance Vector (AODV)[1] routing protocol and Cluster Based Routing Protocol (CBRP)[2]
Resumo:
A mobile ad hoc network MANET is a collection of wireless mobile nodes that can dynamically configure a network without a fixed infrastructure or centralized administration. This makes it ideal for emergency and rescue scenarios where information sharing is essential and should occur as soon as possible. This article discusses which of the routing strategies for mobile ad hoc networks: proactive, reactive and hierarchical, have a better performance in such scenarios. Using a real urban area being set for the emergency and rescue scenario, we calculate the density of nodes and the mobility model needed for validation. The NS2 simulator has been used in our study. We also show that the hierarchical routing strategies are beffer suited for this type of scenarios.
Resumo:
Dynamic thermal management techniques require a collection of on-chip thermal sensors that imply a significant area and power overhead. Finding the optimum number of temperature monitors and their location on the chip surface to optimize accuracy is an NP-hard problem. In this work we improve the modeling of the problem by including area, power and networking constraints along with the consideration of three inaccuracy terms: spatial errors, sampling rate errors and monitor-inherent errors. The problem is solved by the simulated annealing algorithm. We apply the algorithm to a test case employing three different types of monitors to highlight the importance of the different metrics. Finally we present a case study of the Alpha 21364 processor under two different constraint scenarios.
Resumo:
Side Channel Attacks (SCAs) typically gather unintentional (side channel) physical leakages from running crypto-devices to reveal confidential data. Dual-rail Precharge Logic (DPL) is one of the most efficient countermeasures against power or EM side channel threats. This logic relies on the implementation of complementary rails to counterbalance the data-dependent variations of the leakage from dynamic behavior of the original circuit. However, the lack of flexibility of commercial FPGA design tools makes it quite difficult to obtain completely balanced routings between complementary networks. In this paper, a controllable repair mechanism to guarantee identical net pairs from two lines is presented: i. repairs the identical yet conflict nets after the duplication (copy & paste) from original rail to complementary rail, and ii. repairs the non-identical nets in off-the-stock DPL circuits; These rerouting steps are carried out starting from a placed and routed netlist using Xilinx Description Language (XDL). Low level XDL modifications have been completely automated using a set of APIs named RapidSmith. Experimental EM attacks show that the resistance level of an AES core after the automatic routing repair is increased in a factor of at least 3.5. Timing analyses further demonstrate that net delay differences between complementary networks are minimized significantly.
Resumo:
A mobile Ad Hoc network (MANET) is a collection of wireless mobile nodes that can dynamically configure a network without a fixed infrastructure or central administration. This makes it ideal for emergency and rescue scenarios, where sharing information is essential and should occur as soon as possible. This article discusses which of the routing strategies for mobile MANETs: proactive, reactive or hierarchical, has a better performance in such scenarios. By selecting a real urban area for the emergency and rescue scenario, we calculated the density of nodes and the mobility model needed for the validation study of AODV, DSDV and CBRP in the routing model. The NS2 simulator has been used for our study. We also show that the hierarchical routing strategies are better suited for this type of scenarios.
Resumo:
A multivariate analysis on flood variables is needed to design some hydraulic structures like dams, as the complexity of the routing process in a reservoir requires a representation of the full hydrograph. In this work, a bivariate copula model was used to obtain the bivariate joint distribution of flood peak and volume, in order to know the probability of occurrence of a given inflow hydrograph. However, the risk of dam overtopping is given by the maximum water elevation reached during the routing process, which depends on the hydrograph variables, the reservoir volume and the spillway crest length. Consequently, an additional bivariate return period, the so-called routed return period, was defined in terms of risk of dam overtopping based on this maximum water elevation obtained after routing the inflow hydrographs. The theoretical return periods, which give the probability of occurrence of a hydrograph prior to accounting for the reservoir routing, were compared with the routed return period, as in both cases hydrographs with the same probability will draw a curve in the peak-volume space. The procedure was applied to the case study of the Santillana reservoir in Spain. Different reservoir volumes and spillway lengths were considered to investigate the influence of the dam and reservoir characteristics on the results. The methodology improves the estimation of the Design Flood Hydrograph and can be applied to assess the risk of dam overtopping
Resumo:
Conventional dual-rail precharge logic suffers from difficult implementations of dual-rail structure for obtaining strict compensation between the counterpart rails. As a light-weight and high-speed dual-rail style, balanced cell-based dual-rail logic (BCDL) uses synchronised compound gates with global precharge signal to provide high resistance against differential power or electromagnetic analyses. BCDL can be realised from generic field programmable gate array (FPGA) design flows with constraints. However, routings still exist as concerns because of the deficient flexibility on routing control, which unfavourably results in bias between complementary nets in security-sensitive parts. In this article, based on a routing repair technique, novel verifications towards routing effect are presented. An 8 bit simplified advanced encryption processing (AES)-co-processor is executed that is constructed on block random access memory (RAM)-based BCDL in Xilinx Virtex-5 FPGAs. Since imbalanced routing are major defects in BCDL, the authors can rule out other influences and fairly quantify the security variants. A series of asymptotic correlation electromagnetic (EM) analyses are launched towards a group of circuits with consecutive routing schemes to be able to verify routing impact on side channel analyses. After repairing the non-identical routings, Mutual information analyses are executed to further validate the concrete security increase obtained from identical routing pairs in BCDL.
Resumo:
Hoy en día, los sistemas middleware de publicar-suscribir con la filtración de mensajes basado en contenido tiende a ser popularizado, y un sistema como este requiere codificar su mensaje a la combinación de varios elementos que se encuentran en los conjuntos no-interseccionados. Varios predicados posibles en los dominios de esos conjuntos forman un filtro, y el núcleo de algoritmo filtrado es seleccionar filtros adaptados tan pronto como sea posible. Sin embargo, el conjunto, que está formado por los filtros, contiene la extremadamente fuerte indeterminación y distensibilidad, lo que restringe el algoritmo filtrado. Por la resolución de la distensibilidad, se estudió la característica del conjunto de filtros en álgebra, y sabía que es un retículo específico. Por lo tanto, se intenta usar el carácter, el cual los retículos forman un conjunto parcialmente ordenado (o poset, del inglés partially ordered set) con límites, para reducir el tamaño de conjunto de filtros (compresión equivalente). Por estas razones, es necesario implementar un contenedor abstracto de retículo, y evaluar su desempeño tanto en la teoría, como en la práctica, para la solución de la distensibilidad del conjunto de filtros. Retículo (Lattice) es una estructura importante de Álgebra Abstracta, comúnmente se utiliza para resolver el problema teórico, y apenas de ser un contenedor abstracto en la ciencia de software, como resultado de su implementación compleja que proviene de su trivialidad en álgebra. Y por eso se hace difícil mi trabajo. Con el fin de evitar la teoría compleja del sistema práctico, simplemente introduce su núcleo algoritmo, el algoritmo de conteo, y esto llevó a cabo con el problema - la distensibilidad del conjunto de filtros. A continuación, se investigó la solución posible con retículos en la teoría, y se obtuvo el diseño de la implementación, normas para las pruebas xUnit y par´ametros para la evaluación. Por último, señalamos el entorno, el resultado, el análisis y la conclusión de la prueba de rendimiento.
Resumo:
New telecom wavelength sources of polarization entangled photon pairs allow the distribution of entanglement through metro-access networks using standard equipment. This is essential to ease the deployment of future applications that can profit from quantum entanglement, such as quantum cryptography.
Resumo:
The inbound logistic for feeding the workstation inside the factory represents a critical issue in the car manufacturing industry. Nowadays, this issue is even more critical than in the past since more types of car are being produced in the assembly lines. Consequently, as workstations have to install many types of components, they also need to have an inventory of different types of the component in a compact space. The replenishment is a critical issue since a lack of inventory could cause line stoppage or reworking. On the other hand, an excess of inventory could increase the holding cost or even block the replenishment paths. The decision of the replenishment routes cannot be made without taking into consideration the inventory needed by each station during the production time which will depend on the production sequence. This problem deals with medium-sized instances and it is solved using online solvers. The contribution of this paper is a MILP for the replenishment and inventory of the components in a car assembly line.
Resumo:
Recently, the cross-layer design for the wireless sensor network communication protocol has become more and more important and popular. Considering the disadvantages of the traditional cross-layer routing algorithms, in this paper we propose a new fuzzy logic-based routing algorithm, named the Balanced Cross-layer Fuzzy Logic (BCFL) routing algorithm. In BCFL, we use the cross-layer parameters’ dispersion as the fuzzy logic inference system inputs. Moreover, we give each cross-layer parameter a dynamic weight according the value of the dispersion. For getting a balanced solution, the parameter whose dispersion is large will have small weight, and vice versa. In order to compare it with the traditional cross-layer routing algorithms, BCFL is evaluated through extensive simulations. The simulation results show that the new routing algorithm can handle the multiple constraints without increasing the complexity of the algorithm and can achieve the most balanced performance on selecting the next hop relay node. Moreover, the Balanced Cross-layer Fuzzy Logic routing algorithm can adapt to the dynamic changing of the network conditions and topology effectively.
Resumo:
Underwater acoustic sensor networks (UASNs) have become more and more important in ocean exploration applications, such as ocean monitoring, pollution detection, ocean resource management, underwater device maintenance, etc. In underwater acoustic sensor networks, since the routing protocol guarantees reliable and effective data transmission from the source node to the destination node, routing protocol design is an attractive topic for researchers. There are many routing algorithms have been proposed in recent years. To present the current state of development of UASN routing protocols, we review herein the UASN routing protocol designs reported in recent years. In this paper, all the routing protocols have been classified into different groups according to their characteristics and routing algorithms, such as the non-cross-layer design routing protocol, the traditional cross-layer design routing protocol, and the intelligent algorithm based routing protocol. This is also the first paper that introduces intelligent algorithm-based UASN routing protocols. In addition, in this paper, we investigate the development trends of UASN routing protocols, which can provide researchers with clear and direct insights for further research.