the development situation of communication system of small satellites in formation in China and aboard is first introduced. Withthe development of small satellites at present and the needs of small satellites for spa...
详细信息
ISBN:
(纸本)9781612846835
the development situation of communication system of small satellites in formation in China and aboard is first introduced. Withthe development of small satellites at present and the needs of small satellites for space flying mission, the fundamental technologies of hardware structure supporting reconfigurable computing based on FPGA and the distributedcomputing technology are analyzed in this paper. the application of these two technologies in formation-flying pico-satellites communication is demonstrated, and it is verified through an experiment of distributed compressing images that the distribution technology can be implemented in such a reconfigurable hardware structure. the combination of these two technologies can make good use of software and hardware sources of pico-satellite. A design scheme of pico-satellite based on these two technologies is presented at last.
We assume a wireless sensor and actuator network with nodes that can harvest energy from the environment, and an application deployed in this network, which is structured as a set of cooperating mobile components that...
详细信息
ISBN:
(纸本)9780769548791
We assume a wireless sensor and actuator network with nodes that can harvest energy from the environment, and an application deployed in this network, which is structured as a set of cooperating mobile components that can be placed on any node that provides the required sensor and actuator resources. We propose algorithms that take into account the energy consumption rate of agents as well as energy reserves and harvesting rate of nodes, and decide about the migration of agents in order to improve application availability. Initial evaluation results via simulation show that application availability can be greatly improved compared to having a static application placement.
the purpose of this paper is to design and implement a hybrid compiler that combines JOMP's directives with javar's annotations in order to obtain a more performing compiler. this is an original approach and c...
详细信息
ISBN:
(纸本)9780769548791
the purpose of this paper is to design and implement a hybrid compiler that combines JOMP's directives with javar's annotations in order to obtain a more performing compiler. this is an original approach and consists of pooling the advantages of those two compilers while fixing some of their issues. However the achievement of this aim is facing the issue of the difference of implementation of these two compilers because JOMP is implemented in Java while javar is implemented in C language. We propose to entirely re-implement javar in Java by using JavaCC. thereafter, we present the implementation of the hybrid compiler. In the experiments, we propose to parallelize the matrix sort program by using this hybrid compiler. the results of experiments and the mathematical demonstration lead us to state that dealing withthis hybrid compiler gives performances better or equal to the best one between javar and JOMP.
Bag-of-Tasks applications are often composed of a large number of independent tasks;hence, they can easily scale out. With public clouds, the (dynamic) expansion of resource capacity in private clouds is much facilita...
详细信息
ISBN:
(纸本)9780769548791
Bag-of-Tasks applications are often composed of a large number of independent tasks;hence, they can easily scale out. With public clouds, the (dynamic) expansion of resource capacity in private clouds is much facilitated. Clearly, cost efficiently running BoT applications in a multi-cloud environment is of great practical importance. In this paper, we investigate how efficiently multiple clouds can be exploited for running BoT applications and present a fully polynomial time randomized approximation scheme (FPRAS) as a novel task assignment algorithm for BoT applications. the resulting task assignment can be optimized in terms of cost, makespan or the tradeoff between them. the objective function incorporated into our algorithm is devised in the way the optimization objective is tunable based on user preference. Our task assignment decisions are made without any prior knowledge of the processing time of tasks, i.e., non-clairvoyant task assignment. We adopt a Monte Carlo sampling method to estimate unknown task running time. the experimental results shows our algorithm approximates the optimal solution with little overhead.
Since in the large and complex robotic systems such as multiple robot systems, the real robot controllers are spatially distributed according to their physical structure, it is desirable to realize the hierarchical an...
详细信息
An efficient resource management mechanism is important in a heterogeneous system to discover available resources, to allocate an appropriate subset of resources to applications, and to map data or tasks onto selected...
详细信息
ISBN:
(纸本)9780769548791
An efficient resource management mechanism is important in a heterogeneous system to discover available resources, to allocate an appropriate subset of resources to applications, and to map data or tasks onto selected resources. the key component, tasks scheduling, draws our attention. Makespan is the principal concern many existing researches. But, other QoS requirements are also important in more and more realistic applications. Like Grid service it is expected that the service provider be reliable, robust, or highly available. In this study, an existing availability-aware scheduling model called SSAC is investigated first. then, we proposed an optimization approach to increase the availability and to reduce the makespan of tasks running in heterogeneous systems. three quantitative conditions are used to guide the optimization. Our experimental results show that compared withthree existing solutions (Minmin, SSAC and ACO), our algorithm significantly improves the availability and performance of multiclass tasks running in heterogeneous systems.
the unstructured multi-hop radio network model, with asynchronous wake-up, no collision detection and little knowledge on the network topology, is proposed for capturing the particularly harsh characteristics of initi...
详细信息
ISBN:
(纸本)9780769547077
the unstructured multi-hop radio network model, with asynchronous wake-up, no collision detection and little knowledge on the network topology, is proposed for capturing the particularly harsh characteristics of initially deployed wireless ad hoc and sensor networks. In this paper, assuming such a practical model, we study a fundamental problem of boththeoretical and practical interests-the local broadcasting problem. Given a set of nodes V where each node wants to broadcast a message to all its neighbors that are within a certain local broadcasting range R, the problem is to schedule all these requests in the fewest timeslots. By adopting the physical interference model and without any knowledge on neighborhood, we give a new randomized distributed approximation algorithm for the local broadcasting problem with approximation ratio O(log n) where n is the number of nodes. this distributed approximation algorithm improves the state-of-the-art result in [22] by a logarithmic factor.
Wireless technologies are emerging as an important component of our daily life. distributed Coordination Function (DCF) is the basis of IEEE 802.11 WLAN MAC protocol, which uses Carrier Sense Multiple Access with Coll...
详细信息
ISBN:
(纸本)9781457713798
Wireless technologies are emerging as an important component of our daily life. distributed Coordination Function (DCF) is the basis of IEEE 802.11 WLAN MAC protocol, which uses Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocol and binary slotted exponential back-off scheme. DCF implementation specified by the IEEE 802.11 standard reset the contention window (CW) to minimum value upon a successful transmission. Although the new CW is minimal the congestion level goes gradually to minimum, causing the node to probably waste time and channel bandwidth going through several collisions and retransmissions before reaching a CW value corresponds to the congestion level. this paper modifies the implementation to reduce the window to half its size after a successful transmission. the paper uses analytical and simulation analysis to show throughput improvements under ideal and non-ideal channel with channel induced errors and capture effect. When compared to the standard implementation, throughput has improved for both ideal and non ideal channel.
this research is investigated on the multi-objective performance optimization of a parallel robotic machine tool which is expected to be applied as a next generation of computer numerical control (CNC) machine. the sy...
详细信息
the 8th IEEE internationalconference on distributedcomputing in Sensor Systems (DCOSS 2012) is taking place in Hangzhou, China, from Wednesday, May 16, to Friday, May 18, 2012. Previous editions have taken place in ...
详细信息
暂无评论