12322208
Gemini: Probabilistic Routing Algorithm in Structured P2P Overlay
In this paper, we propose a new structured overlay protocol, which is more efficient and scalable than previous ones. We call it Gemini, because its routing table consists of two parts, one containing nodes with common prefix and the other containing nodes with common suffix. Gemini routes messages to their destinations in just 2 hops, with a very high probability of 0.99. When running in a p2p network of 5,000,000 peers, each Gemini node consumes only 6 messages per second for maintenance. This cost, as well as routing table size, varies as a \(O {\sqrt{N}}\) function to the overlay scale, so Gemini can also run well in an even larger environment.
16584711
PeerWindow: an efficient, heterogeneous, and autonomic node collection protocol
Nodes in peer-to-peer systems need to know the information about others to optimize neighbor selection, resource exchanging, replica placement, load balancing, query optimization, and other collaborative operations. However, how to collect this information effectively is still an open issue. In this paper, we propose a novel information collection protocol, PeerWindow, with which each node can collect a large amount of pointers to other nodes at a very low cost. Compared to existing protocols, PeerWindow is 1) efficient, the cost of collecting 1,000 pointers being less than 1 kbps in a common system environment, 2) heterogeneous, nodes with different capacities collecting different amounts of information, and 3) autonomic, nodes determining their bandwidth cost for node collection by themselves and adjusting it dynamically. PeerWindow can be used in many existing peer-to-peer systems and has tremendous potential for future expansions.
6072229
PRESTO: feedback-driven data management in sensor networks
This paper presents PRESTO, a novel two-tier sensor data management architecture comprising proxies and sensors that cooperate with one another for acquiring data and processing queries. PRESTO proxies construct time-series models of observed trends in the sensor data and transmit the parameters of the model to sensors. Sensors check sensed data with model-predicted values and transmit only deviations from the predictions back to the proxy. Such a model-driven push approach is energy-efficient, while ensuring that anomalous data trends are never missed. In addition to supporting queries on current data, PRESTO also supports queries on historical data using interpolation and local archival at sensors. PRESTO can adapt model and system parameters to data and query dynamics to further extract energy savings. We have implemented PRESTO on a sensor testbed comprising Intel Stargates and Telos Motes. Our experiments show that in a temperature monitoring application, PRESTO yields one to two orders of magnitude reduction in energy requirements over on-demand, proactive or model-driven pull approaches. PRESTO also results in an order of magnitude reduction in query latency in a 1% duty-cycled five hop sensor network over a system that forwards all queries to remote sensor nodes.
32144441
SmartBoa: Constructing p2p Overlay Network in the Heterogeneous Internet Using Irregular Routing Tables
The high heterogeneity of large-scale p2p system leads us to the philosophy that the size of a node’s routing table and its updating cost should correspond to the node’s capacity. With this philosophy, we design a novel structured overlay: SmartBoa. SmartBoa categorizes nodes into different levels according to their capacities. A node at level k has a routing table with N/2k entries (N is the system scale). An efficient non-redundant multicast algorithm is introduced to distribute nodes’ changing reports. With the multicast the routing table’s updating cost is in proportion to its size. Node can change its level freely so as to adapt to fluctuation of the system. At the same cost as the O(log N) overlay, SmartBoa maintains with much larger routing tables and has much higher routing efficiency. A low-bandwidth (64 kbps) node can maintain 10,000 routing entries at the cost of only 10 percent of its bandwidth. Without the high bandwidth requirement of an one-hop overlay, SmartBoa is much more scalable.
46138782
Leveraging legacy codes to distributed problem-solving environments: a Web services approach
This paper presents WSOWG, a Web-services-oriented wrapper generator for automatically wrapping non-networked legacy codes as Web services for reuse in distributed problem-solving environments. Using WSOWG, a finite element based computational fluid dynamics (CFD) legacy code has been wrapped as a Web service. A problem-solving environment for simulating incompressible Navier-Stokes flows has also been implemented. A user makes use of the CFD service through a Web page without knowing the exact implementation of the service. In this way, a user's computing environment can be extended to a heterogeneous distributed computing environment. Performance evaluation shows that the overhead to invoke the CFD Web service generated by WSOWG using Simple Object Access Protocol (SOAP) and CORBA Internet Inter-ORB Protocol (IIOP) is reasonable compared with that of invoking another CFD Web service manually wrapped from the CFD legacy code using SOAP only.
7419462
End-to-end framework for QoS guarantee in heterogeneous wired-cum-wireless networks
With information access becoming more and more ubiquitous, there is a need for providing QoS support for communication that spans wired and wireless networks. For the wired side, RSVP/SBM has been widely accepted as a flow reservation scheme in IEEE 802 style LANs. In this paper, we investigate the integration of RSVP and a RSVP-like flow reservation scheme in wireless LANs, as an end-to-end solution for QoS guarantee in wired-cum-wireless networks. We propose WRESV, an RSVP-like flow reservation and admission control scheme for IEEE 802.11 wireless LAN. Using WRESV, wired/wireless integration can be easily implemented by cross-layer interaction at the access point. Main components of the integration are RSVP-WRESV parameter mapping, and the initiation of new reservation messages, depending on where senders/receivers are located. In addition, we also propose various optimizations for supporting multicast session, mobility management, and admission control.
42814281
Fixed Topology Alignment with Recombination
In this paper, we study a new version of multiple sequence alignment, fixed topology alignment with recombination. We show that it can not be approximated within any constant ratio unless P = NP. For a more restricted version, we show that the problem is MAX-SNP-hard. This implies that there is no PTAS for this version unless P = NP. We also propose approximation algorithms for a special case, where each internal node has at most one recombination child and any two merge paths for different recombination nodes do not share any common node.
1528533
Application, Network and Link Layer Measurements of Streaming Video over a Wireless Campus Network
The growth of wireless LANs has brought the expectation for high-bitrate streaming video to wireless PCs. However, it remains unknown how to best adapt video to wireless channel characteristics as they degrade. This paper presents results from experiments that stream commercial video over a wireless campus network and analyze performance across application, network and wireless link layers. Some of the key findings include: 1) Wireless LANs make it difficult for streaming video to gracefully degrade as network performance decreases; 2) Video streams with multiple encoding levels can more readily adapt to degraded wireless network conditions than can clips with a single encoding level; 3) Under degraded wireless network conditions, TCP streaming can provide higher video frame rates than can UDP streaming, but TCP streaming will often result in significantly longer playout durations than will UDP streaming; 4) Current techniques used by streaming media systems to determine effective capacity over wireless LAN are inadequate, resulting in streaming target bitrates significantly higher than can be effectively supported by the wireless network.
44742126
A New Association Rules Mining Algorithms Based on Directed Itemsets Graph
In this paper, we introduced a new data structure called DISG (Directed itemsets graph) in which the information of frequent itemsets was stored. Based on it, a new algorithm called DBDG (DFS Based -DISG) was developed by using depth first searching strategy. At last we performed a experiment on a real dataset to test the run time of DBDG. The experiment showd that it was efficient for mining dense datasets.