Modern methods in molecular biology produce a tremendous amount of data. As a consequence, efficient methods have to be developed to retrieve and analyze these data. In this article, a parallel algorithm searching mot...
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Modern methods in molecular biology produce a tremendous amount of data. As a consequence, efficient methods have to be developed to retrieve and analyze these data. In this article, a parallel algorithm searching motifs based on ParSeq, a software tool for motif search, is put forward and its performance analyzed and discussed. Many experiments show that with this parallel algorithm a considerable improvement upon the sequential motif search algorithm is achieved.
This paper revisits the interconnection of self-stabilization and fault-tolerance. Self-stabilizing algorithms are able to recover from arbitrary system states given that from some point in time on, there are no fault...
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This paper revisits the interconnection of self-stabilization and fault-tolerance. Self-stabilizing algorithms are able to recover from arbitrary system states given that from some point in time on, there are no faults. Fault-tolerance, on the other hand, refers to algorithms that cope with systems where a (bounded) part of the system (e.g. at most f out of n processes) may fail permanently. In previous work [16] we considered the interconnection of these two paradigms, i.e., algorithms that recover from arbitrary states despite of permanent faults. We have shown that in certain settings, problems as failure detection cannot be solved. This paper presents ways to circumvent this impossibility result.
Node churn and failures exist as fundamental characteristics in both peer-to-peer (P2P) and sensor networks. Peers in P2P networks are highly dynamic, whereas sensors are not dependable. As such, maintaining the persi...
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Node churn and failures exist as fundamental characteristics in both peer-to-peer (P2P) and sensor networks. Peers in P2P networks are highly dynamic, whereas sensors are not dependable. As such, maintaining the persistence of periodically measured data in a scalable fashion has become a critical challenge in such systems, without the use of centralized servers. To better cope with node dynamics and failures, we propose priority random linear codes (RLCs), as well as their affiliated predistribution protocols, to maintain measurement data in different priorities, such that critical data have a higher opportunity to survive node failures than data of less importance. A salient feature of priority RLCs is the ability to partially recover more important subsets of the original data with higher priorities, when it is not feasible to recover all of them due to node dynamics. We present extensive analytical and experimental results to show the effectiveness of priority RLCs.
This paper introduces SCCB1 cluster system in which SCC PCI boards are implemented. SCCB cluster is built using PCs(32nodes) for processor, and two networks. SCC PCI boards allow to fast barrier synchronization mechan...
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This paper introduces SCCB1 cluster system in which SCC PCI boards are implemented. SCCB cluster is built using PCs(32nodes) for processor, and two networks. SCC PCI boards allow to fast barrier synchronization mechanism and *** order to perform fast synchronization, each SCC board is connected by a new type of network, and checks completion of barrier by hardware. PGCCS allows us to measure execution times accurately on the Beowulf clusters. In performance evaluation, SCC board plugged into 32-nodes PC cluster achieves barrier latency of 3.2 μ8. Time difference errors of PGCCS were smaller (1/100) than that of a conventional method using MPLBarrier.
Dynamic optimization technology improves its target system on the fly according to the system status. There are some studies on microprocessors to dynamically improve performance and energy efficiency. We are investig...
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Dynamic optimization technology improves its target system on the fly according to the system status. There are some studies on microprocessors to dynamically improve performance and energy efficiency. We are investigating a software-based dynamic optimization mechanism on a multi-threaded processor to improve performance. Optimization is performed on binary codes. To optimize binary codes dynamically, profile information is required. Gathering profiles suffers overhead, and thus low overhead scheme is strongly required. This paper proposes to utilize helper threads to gather profile information with little overhead. Simulation results are also presented.
This article presents a new distributed approach for generating all prime numbers up to a given limit. From Eratosthenes, who elaborated the first prime sieve (more than 2000 years ago), to the advances of the paralle...
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This article presents a new distributed approach for generating all prime numbers up to a given limit. From Eratosthenes, who elaborated the first prime sieve (more than 2000 years ago), to the advances of the parallel computers (which have permitted to reach large limits or to obtain the previous results in a shorter time), prime numbers generation still represents an attractive domain of research. Nowadays, prime numbers play a central role in cryptography and their interest has been increased by the very recent proof that primality testing is in P. In this work, we propose a new distributed algorithm which generates all prime numbers in a given finite interval [2,..., n], based on the wheel sieve. As far as we know, this paper designs the first fully distributed wheel sieve algorithm.
Nowadays Internet users participate in different types of collaborative applications from different parts of the world. In these types of applications, users need to coordinate access to shared resources. This coordin...
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ISBN:
(纸本)9780889868113
Nowadays Internet users participate in different types of collaborative applications from different parts of the world. In these types of applications, users need to coordinate access to shared resources. This coordination is termed as floor control and researchers have proposed different types of floor control protocols in the literature. Certain types of collaborative applications require that a user with higher priority will be given preference over a user with lower priority at the time of floor assignment by the underlying protocol. This implies that the protocol needs to consider the priority of the user while assigning the floor. If two users are contending for the floor and their priorities are same, then the user who has requested the floor first will get the floor before the other user. These applications also require that this coordination should be performed without the help of any centralized controller. In this paper, we propose GPRIDE - a Generalized PRIority-based distributed floor control protocol for collaborative applications. We have implemented our proposed protocol using BSD Sockets API and tested the performance of the protocol on the PlanetLab network for different conditions. PlanetLab is an overlay testbed that connects several academic and research institutions all over the world in a virtual network.
This paper presents a new method of self-stabilizing token passing for mutual exclusion in mobile ad hoc networks. Since link failures may frequently occur in the environment, it is desirable to recover from such fail...
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This paper presents a new method of self-stabilizing token passing for mutual exclusion in mobile ad hoc networks. Since link failures may frequently occur in the environment, it is desirable to recover from such failures by itself. So we seek a self-stabilizing solution tolerating partitioning failures. A dynamic BFS tree rooted at a token process is constructed and plays a role in monitoring partitioning failures. If a partitioned component has not had any token, a token will be regenerated by timeout mechanism. Otherwise, the tree rooted at a token will eliminate temporary tokens. For servicing a request, another kind of dynamic BFS tree rooted at each request is concurrently constructed. By using fair composition technique, tolerating partitioning failures can be achieved in self-stabilizing token passing. Finally, some properties of our method and stabilization time are investigated.
One of the basic services in the Grid is resource discovery. When a user request services, he gives a set of attributes that should be satisfied by a candidate resource. The resource discovery mechanism returns a set ...
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One of the basic services in the Grid is resource discovery. When a user request services, he gives a set of attributes that should be satisfied by a candidate resource. The resource discovery mechanism returns a set of best resources for the given set of attributes. We present two P2P protocols for resource discovery: the Query Resource Discovery Mechanism (QRDM), and the Seeking Resource Discovery Mechanism (SRDM). They are based on the main characteristics of P2P systems: decentralization and selforganization.
This paper considers solving consensus in an n-process distributed system where the processes are pairwise connected by reliable links and up to f i1-bisource is enough for solving consensus. That is, if the links bet...
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ISBN:
(纸本)9780889868113
This paper considers solving consensus in an n-process distributed system where the processes are pairwise connected by reliable links and up to f i1-bisource is enough for solving consensus. That is, if the links between a correct process and all the other processes are eventually timely, consensus can be solved. This paper show that a }3f -bisource is also enough, so we only require that the links between some correct process and 3f (instead of all) other processes are eventually timely. The significance lies in that the degree of synchrony needed to solve consensus relies on only the resilience (that is, f), independent of the scale n of the system.
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