Collecting information about user activity in peer-to-peer systems is a key but challenging task. We describe here a distributed platform for doing so on the eDonkey network, relying on a group of honeypot peers which...
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ISBN:
(纸本)9781424437511
Collecting information about user activity in peer-to-peer systems is a key but challenging task. We describe here a distributed platform for doing so on the eDonkey network, relying on a group of honeypot peers which claim to have certain files and log queries they receive for these files. We then conduct some measurements with typical scenarios and use the obtained data to analyze the impact of key parameters like measurement duration, number of honeypots involved, and number of advertised files. This illustrates both the possible uses of our measurement system, and the kind of data one may collect using it.
Many image and signal processing kernels can be optimized for performance consuming a reasonable area by doing loops parallelization with extensive use of pipelining. This paper presents an automated flexible pipeline...
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ISBN:
(纸本)9781424437511
Many image and signal processing kernels can be optimized for performance consuming a reasonable area by doing loops parallelization with extensive use of pipelining. This paper presents an automated flexible pipeline design algorithm for our unique acceleration technique called Recursive Variable Expansion. The preliminary experimental results on a kernel of real life application shows comparable performance to hand optimized implementation in reduced design time. This make it a good choice for generating high performance code for kernels which satisfy the given constraints, for which hand optimized codes are not available.
XMPP (XML Messaging and Presence Protocol), also known as Jabber, is a popular instant messaging protocol that uses XML streams for communication. Due to it's high extensibility, XMPP is very easy to adapt to othe...
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ISBN:
(纸本)9781424437511
XMPP (XML Messaging and Presence Protocol), also known as Jabber, is a popular instant messaging protocol that uses XML streams for communication. Due to it's high extensibility, XMPP is very easy to adapt to other uses than instant messaging. Furthermore, announcing of presence state makes it ideal for highly volatile environments. This paper outlines the use of XMPP for a grid-like computation environment. The biggest advantage of this setup was that available computing resources, such as laboratory computers, could be connected easily and used similarly to a grid. The application example described in this paper uses Ant Colony System (ACS) optimisation and the NEC-tool to optimise RFID antennas, involving computing the efficiency and resonant frequency of a large number of different antenna structures.
This paper presents many typical problems that are encountered when executing large scale scientific applications over distributed architectures. The causes and effects of these problems are explained and a solution f...
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ISBN:
(纸本)9781424437511
This paper presents many typical problems that are encountered when executing large scale scientific applications over distributed architectures. The causes and effects of these problems are explained and a solution for some classes of scientific applications is also proposed. This solution is the combination of the asynchronous iteration model with JACEP2P-V2 which is a filly decentralized and fault tolerant platform dedicated to executing parallel asynchronous applications over volatile distributed architectures. We explain in detail how our approach deals whit each of these problems. Then we present two large scale numerical experiments that prove the efficiency and the robustness of our approach.
We consider the operator mapping problem for in-network stream processing, i.e., the application of a tree of operators in steady-state to multiple data objects that are continuously updated at various locations in a ...
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ISBN:
(纸本)9781424437511
We consider the operator mapping problem for in-network stream processing, i.e., the application of a tree of operators in steady-state to multiple data objects that are continuously updated at various locations in a network. Examples of in-network stream processing include the processing of data in a sensor network, or of continuous queries on distributed relational databases. Our aim is to provide the user a set of processors that should be bought or rented in order to ensure that the application achieves a minimum steady-state throughput, and with the objective of minimizing platform cost. We prove that even the simplest variant of the problem is NP-hard, and we design several polynomial time heuristics, which are evaluated via extensive simulations and compared to theoretical bounds.
parallel applications typically run. in batch mode, sometimes after long waits in a scheduler queue. In some situations, it would be desirable to interactively add new functionality to the running application, without...
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ISBN:
(纸本)9781424437511
parallel applications typically run. in batch mode, sometimes after long waits in a scheduler queue. In some situations, it would be desirable to interactively add new functionality to the running application, without having to recompile and rerun it. For example, a debugger could upload code to perforin consistency checks, or a data analyst could upload code to perform new statistical tests. This paper presents a scalable technique to dynamically insert code into running parallel applications. We describe and evaluate an implementation of this idea that allows a user to upload Python code into running parallel applications. This uploaded code will run in concert with the main code. We prove the effectiveness of this technique in two case studies: parallel debugging to support introspection and data analysis of large cosmological datasets.
Financial institutions have massive computations to carry out overnight which are very demanding in terms of the consumed CPU. The challenge is to price many different products oil a cluster-like architecture. We have...
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ISBN:
(纸本)9781424437511
Financial institutions have massive computations to carry out overnight which are very demanding in terms of the consumed CPU. The challenge is to price many different products oil a cluster-like architecture. We have used the Premia software to valuate the financial derivatives. In this work, we explain how Premia can be embedded into Nsp, a scientific software like Matlab, to provide a powerful tool to valuate a whole portfolio. Finally;we have integrated an MPI toolbox into Nsp to enable to use Premia to solve a bunch of pricing problems on a cluster. This unified framework can then be used to test different parallel architectures.
Most conventional parallel job schedulers only, support static scheduling thereby restricting schedulers from being able to modify the number of processors allocated to parallel applications at runtime. The drawbacks ...
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ISBN:
(纸本)9781424437511
Most conventional parallel job schedulers only, support static scheduling thereby restricting schedulers from being able to modify the number of processors allocated to parallel applications at runtime. The drawbacks of static scheduling can be overcome by using scheduling policies that can exploit dynamic resizability in distributed-memory parallel applications and a scheduler that supports these policies. The scheduler must be capable of adding and removing processors from a parallel application at runtime. This ability of a scheduler to resize parallel applications increases the possibilities for parallel schedulers to manage a large cluster Our ReSHAPE framework includes an application scheduler that supports dynamic resizing of parallel applications. In this paper we illustrate the impact of dynamic resizability on parallel scheduling. We propose and evaluate new scheduling policies made possible by our ReSHAPE framework. Experimental results show that these scheduling policies significantly improve individual application turn around time as well as overall cluster utilization.
This paper introduces an extensible distributed file system framework, YaFS, using heterogeneous online storage services as its back-ends. It provides a configurable solution for simplifying the usage of multiple stor...
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ISBN:
(纸本)9781424437511
This paper introduces an extensible distributed file system framework, YaFS, using heterogeneous online storage services as its back-ends. It provides a configurable solution for simplifying the usage of multiple storage resources and accessing data ubiquitously and safely. YaFS is POSIX compliant, so that it could support most of the existing applications seamlessly. An of line mode is used to cope with the challenged unreliable network environment. We implement a storage abstraction layer and a plug-in mechanism for uniformly accessing different storage services transparently, and it makes the system expanded easily. YaFS could effectively support for storing large object to size limited services and achieving high aggregate bandwidth by striping data on multiple servers with bandwidth-saving method. The evaluation on a prototype implementation with email services as its storage back-end shows that the performance and usability of the framework is viable.
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