Network emulation environment is great importance to the research of network protocols, applications and security mechanism. Large-scale network topology generation is one of key technologies to construct network emul...
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Insects build architecturally complex nests and search for remote food by collaboration work despite their limited sensors, minimal individual intelligence and the lack of a central control system. Insets' co...
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ISBN:
(纸本)9781424472796
Insects build architecturally complex nests and search for remote food by collaboration work despite their limited sensors, minimal individual intelligence and the lack of a central control system. Insets' collaborations emerge as a response of the individual insects to Stigmergy. A sign-based model of Stigmergy to discuss collaboration is proposed in this paper where we picked up "sign" as a key notion to understand it. Therefore, sign is the link of all the components in a Stigmergic complex adaptive system. Based on this understanding, we propose a definition that reveals the nature of signs and exploit the significations and relationships carried by the notion of sign. Then, a sign-based model of Stigmergy is consequently reached, which captures the essentials of Stigmergy. A basic architecture of Stigmergy as well as its constituents are presented and discussed. At last, some applications of the model are discussed.
Existing routing protocols for Wireless Mesh Networks (WMNs) are generally optimized with statistical link measures, while not addressing on the intrinsic uncertainty of wireless links. We show evidence that, with the...
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Existing routing protocols for Wireless Mesh Networks (WMNs) are generally optimized with statistical link measures, while not addressing on the intrinsic uncertainty of wireless links. We show evidence that, with the transient link uncertainties at PHY and MAC layers, a pseudo-deterministic routing protocol that relies on average or historic statistics can hardly explore the full potentials of a multi-hop wireless mesh. We study optimal WMN routing using probing-based online anypath forwarding, with explicit consideration of transient link uncertainties. We show the underlying connection between WMN routing and the classic Canadian Traveller Problem (CTP). Inspired by a stochastic recoverable version of CTP (SRCTP), we develop a practical SRCTP-based online routing algorithm under link uncertainties. We study how dynamic next hop selection can be done with low cost, and derive a systematic selection order for minimizing transmission delay. We conduct simulation studies to verify the effectiveness of the SRCTP algorithms under diverse network configurations. In particular, compared to deterministic routing, reduction of end-to-end delay (51.15~73.02%) and improvement on packet delivery ratio (99.76%) are observed.
In large-scale asynchronous distributed virtual environments(DVEs), one of the difficult problems is to deliver the concurrent events in a consistent order at each node. Generally, the previous consistency control app...
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According to Moore's law the complexity of VLSI circuits has doubled approximately every two years, resulting in simulation becoming the major bottleneck in the circuit design process. parallel and distributed sim...
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According to Moore's law the complexity of VLSI circuits has doubled approximately every two years, resulting in simulation becoming the major bottleneck in the circuit design process. parallel and distributed simulations can be applied as fast, cost effective approaches to the simulation of large, complex circuits. In this paper, a simple yet effective simulated annealing-based approach is proposed to optimize the choice of a time window for optimistic parallel simulation. We chose gate level circuits simulations as our experimental vehicle. Our results show up to a 52% improvement in the simulation time using our simulated annealing algorithm. To the best of our knowledge, this is the first time that SA has been applied to optimize the performance of time warp simulations.
To efficiently perform large matrix LU decomposition on FPGAs with limited local memory, the original algorithm needs to be blocked. In this paper, we propose a block LU decomposition algorithm for FPGAs, which is app...
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To efficiently perform large matrix LU decomposition on FPGAs with limited local memory, the original algorithm needs to be blocked. In this paper, we propose a block LU decomposition algorithm for FPGAs, which is applicable for matrices of arbitrary size. We introduce a high performance hardware design, which mainly consists of a linear array of processing elements (PEs), to implement our block LU decomposition algorithm. A total of 36 PEs can be integrated into a Xilinx Virtex-5 xc5vlx330 FPGA on our self-designed PCI-Express card, reaching a sustained performance of 8.50 GFLOPS at 133 MHz, which outperforms previous work.
LEDBAT is a new congestion control algorithm which was proposed in an IETF draft in March 2009. LEDBAT's goal is to provide a less-than-best-effort data transport service, i.e. a LEDBAT flow should back-off in the...
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LEDBAT is a new congestion control algorithm which was proposed in an IETF draft in March 2009. LEDBAT's goal is to provide a less-than-best-effort data transport service, i.e. a LEDBAT flow should back-off in the presence of other competing flows (TCP flows in particular). Because of its intended friendliness to competing flows, LEDBAT has already been implemented in the popular Bittorrent client uTorrent. In this paper we present performance evaluation results for our Python implementation of LEDBAT. We ran tests both in emulated networks as well as in real world networks. One of the tests involved approximately 300 volunteers spread throughout the world.
How to preserve causal and totally ordered event delivery is an important issue in real-time serverless DVE(distributed Virtual Environment). However, most of the related works are designed to maintain causal order me...
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How to preserve causal and totally ordered event delivery is an important issue in real-time serverless DVE(distributed Virtual Environment). However, most of the related works are designed to maintain causal order merely or time stamped order with intensive computation and bandwidth overhead. In this paper, we proposed a novel distributed algorithm to maintain the before-and-after relationship between events, both causal and concurrent, of DVE at each individual node. Several simulation experiments are carried out to evaluate the performance of our algorithm and the results demonstrate that the algorithm is effective in preserving causal and totally ordered event delivery and more efficient than the previous algorithms.
Encryption technology has become an important mechanism of securing data stored in the outsourced database. However, it is a difficulty to query efficiently the encrypted data and many researchers take it into conside...
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ISBN:
(纸本)9781424477050
Encryption technology has become an important mechanism of securing data stored in the outsourced database. However, it is a difficulty to query efficiently the encrypted data and many researchers take it into consideration. To solve the problem, an encrypted schema, based on the Postgresql DBMS, is proposed. Through the security dictionary and the extended SQL, the approach implements the encrypted storage and efficiently query over the encrypted data in the outsourced databases. Results of experiments validate the efficiency and feasibility of our approach.
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