7423428
Optimal Power Allocation in Wireless Networks with Transmitter-Receiver Power Tradeoffs
For many wireless communication links, such as those employing turbo codes or sequentially-decoded convolutional codes, the power consumption of the decoder at the receiver depends on the received signal power and, hence, on the transmitted signal power. By transmitting a signal at a power higher than the minimum required for successful reception, the transmitter can “assist” the receiver by reducing the receiver decoding effort and thereby reducing the overall power consumption on the link. In this paper, we consider sender-receiver power tradeoffs in data-gathering trees. We formulate an optimization problem to optimally assign power to the nodes in the tree for maximizing the lifetime of the data-gathering tree, which is equivalent to the time until network partition due to battery outage. We propose a Binary Search Algorithm for optimal power assignment among nodes that maximizes the tree lifetime. Our Binary Search Algorithm can be easily extended to handle practical considerations such as node mobility and peak power constraints at nodes. Using turbo codes as an example of a channel coding technique, we demonstrate significant improvements in network lifetimes as a result of sender-receiver power tradeoffs. These improvements are observed under a wide variety of network conditions and are more pronounced in densely deployed networks and networks with asymmetric power costs.
14748826
QoS-Aware Optimization of Composite-Service Fulfillment Policy
In a service-oriented IT infrastructure, functional capabilities of a computing component are externalized via one or more service interfaces. Driven by the demand for business agility and return-on-investment optimization, various dynamic service discovery and composition technologies have been proposed and developed with a common goal of enabling business-aligned fulfillment of customer requests. However, from the viewpoint of capacity planning and IT optimization, much work is still needed in helping an enterprise decide the "optimal" IT resources necessary for deploying the atomic services in support of those composite ones. The service deployment decision must be integrated with the request fulfillment policy so that the differentiated quality-of-service (QoS) requirements of service requests can be met, for instance, with minimum hardware/software cost. In this paper, we propose an approach for QoS-aware optimization of composite-service fulfillment policy. Without loss of generality, we assume that the optimization goal is to minimize the number of machines subject to response time and throughput requirements. After presenting our approach to the optimization problem using the assumption, we show that an NP-hard throughput optimization problem must be attacked. We then illustrate how we attack the problem via an efficient heuristic algorithm. The algorithm decomposes the end-to-end response time requirement for each type of composite service into atomic-service level response time assurance, and co-locate atomic services with similar response time assurance on machines with similar utilization characteristics. The algorithm exemplifies an integrated approach to optimizing service deployment and service composition. We demonstrate that the algorithm achieves a substantially higher throughput than a common baseline algorithm.
206924421
Classification of access network types: Ethernet wireless LAN, ADSL, cable modem or dialup?
Ethernet, wireless LAN, ADSL, cable modem and dialup are common access networks, but have dramatically different characteristics. Fast and accurate classification of access network type can improve protocol or application performance significantly. In this paper, we propose a simple and efficient end-end scheme to classify the type of an access network into three categories: Ethernet, wireless LAN and low-bandwidth connection. Our scheme is based on the intrinsic characteristics of the various access networks and utilizes the median and entropy of packet pair inter-arrival times. Extensive experiments show that our scheme obtains accurate classification results in a very short time (10 to 100 seconds).
15177304
A new method of color image segmentation based on intensity and hue clustering
A new method of color image segmentation is proposed. It is based on the K-means algorithm in HSI color space and has the advantage over those based on the RGB space. Both the hue and the intensity components are fully utilized. In the process of hue clustering, the special cyclic property of the hue component is taken into consideration. The paper gives the definition of the distance and the center in the hue space, based on which the hue-clustering algorithm is implemented. Utilised in medical image processing, the new method gives a good performance.
1748998
Minimum Register Instruction Scheduling: A New Approach for Dynamic Instruction Issue Processors
Modern superscalar architectures with dynamic scheduling and register renaming capabilities have introduced subtle but important changes into the tradeoffs between compile-time register allocation and instruction scheduling. In particular, it is perhaps not wise to increase the degree of parallelism of the static instruction schedule at the expense of excessive register pressure which may result in additional spill code. To the contrary, it may even be beneficial to reduce the register pressure at the expense of constraining the degree of parallelism of the static instruction schedule. This leads to the following interesting problem: given a data dependence graph (DDG) G, can we derive a schedule S for G that uses the least number of registers ? 
 
In this paper, we present a heuristic approach to compute the near-optimal number of registers required for a DDG G (under all possible legal schedules). We propose an extended list-scheduling algorithm which uses the above number of required registers as a guide to derive a schedule for G that uses as few registers as possible. Based on such an algorithm, an integrated approach for register allocation and instruction scheduling for modern superscalar architectures can be developed.
28540558
A Serving Agent for Integrating Soft Computing and Software Agents
This paper discusses the design and implementation of a serving agent for integrating soft computing and software agents.
16767212
A Robust Method for Biological Sequence Clustering
In this paper, we proposed a two-phase hybrid method for biological sequence clustering, which combines the strengths of the hierarchical agglomerative clustering methods and the partition clustering methods. In phase I, the hybrid method uses the hierarchical agglomerative clustering algorithm to pre-cluster the aligned sequences, while in the second phase it takes the pre-clustering result as the initial partition for the profile hidden Markov models (HMMs) based k-means partition clustering method. Such initial partitions (generated from phase I), as against random initial partitions, are usually more reasonable and thus can avoid the inconsistency problem in the partition clustering methods due to the randomness in initial partitions. In addition, the inaccuracy of the hierarchical agglomerative clustering methods can be compensated by the profile HMM based k-means partition clustering since the latter is model-based and can better describe the dynamic properties of the data in a cluster. Experiments on a molecular sequence dataset demonstrate the effectiveness and the efficiency of the proposed hybrid clustering algorithm
3978452
The Interaction Between Window Adjustment Strategies and Queue Management Schemes
In this paper, we investigate extensively the joint network dynamics with different AIMD window-adjustment parameters on end-hosts, and different queue management schemes (i.e. DropTail vs. RED) in routers. We reveal that with DropTail buffer, although smooth TCPs causes less queuing-delay jitter, its average queuing delay is significantly higher than that of responsive TCPs. The direct implication of this discovery is that when mobile users of media-streaming and short messages share a bottleneck link, the energy consumption for sending short messages can increase severely if media-streaming users adopt smooth TCPs. With RED, on the other hand, smooth TCPs not only lead to smaller queue oscillation, the average/max queue length is smaller as well.