Improvement of fingerprint retrieval by a statistical classifier

The topics of fingerprint classification, indexing, and retrieval have been studied extensively in the past decades. One problem faced by researchers is that in all publicly available fingerprint databases, only a few fingerprint samples from each individual are available for training and testing, making it inappropriate to use sophisticated statistical methods for recognition. Hence most of the previous works resorted to simple $k$-nearest neighbor ($k$-NN) classification. However, the $k$-NN classifier has the drawbacks of being comparatively slow and less accurate. In this paper, we tackle this problem by first artificially expanding the set of training samples using our previously proposed spatial modeling technique. With the expanded training set, we are then able to employ a more sophisticated classifier such as the Bayes classifier for recognition. We apply the proposed method to the problem of one-to-$N$ fingerprint identification and retrieval. The accuracy and speed are evaluated using the benchmarking FVC 2000, FVC 2002, and NIST-4 databases, and satisfactory retrieval performance is achieved. © 2010 IEEE.published_or_final_versio

Recognition of handwritten Chinese characters by combining regularization, Fisher's discriminant and distorted sample generation

Proceedings of the 10th International Conference on Document Analysis and Recognition, 2009, p. 1026–1030The problem of offline handwritten Chinese character recognition has been extensively studied by many researchers and very high recognition rates have been reported. In this paper, we propose to further boost the recognition rate by incorporating a distortion model that artificially generates a huge number of virtual training samples from existing ones. We achieve a record high recognition rate of 99.46% on the ETL-9B database. Traditionally, when the dimension of the feature vector is high and the number of training samples is not sufficient, the remedies are to (i) regularize the class covariance matrices in the discriminant functions, (ii) employ Fisher's dimension reduction technique to reduce the feature dimension, and (iii) generate a huge number of virtual training samples from existing ones. The second contribution of this paper is the investigation of the relative effectiveness of these three methods for boosting the recognition rate. © 2009 IEEE.published_or_final_versio

Quality-of-service routing with two concave constraints

Routing is a process of finding a network path from a source node to a destination node. A good routing protocol should find the "best path" from a source to a destination. When there are independent constraints to be considered, the "best path" is not well-defined. In our previous work, we developed a line segment representation for Quality-of-Service routing with bandwidth and delay requirements. In this paper, we propose how to adopt the line segment when a request has two concave constraints. We have developed a series of operations for constructing routing tables under the distance-vector protocol. We evaluate the performance through extensive simulations. ©2008 IEEE.published_or_final_versio

THE PENALTY RULE: A MODERN INTERPRETATION

This paper focuses on the common law doctrine of the penalty rule and the recent Supreme Court decision in Cavendish Square Holding v Makdessi and ParkingEye v Beavis. The state of the penalty rule prior to the judgment was unsatisfactory and criticized by both commentators and practitioners alike. Its indiscriminate application and unclear criteria was a needless source of uncertainty for both contracting parties and lawyers. Nevertheless, their Lordships in Cavendish refused to abolish the penalty rule but acknowledged its limited application in the modern commercial context. This paper accordingly aims to justify the continued existence of the doctrine on theoretical grounds within the English private law framework despite its practical obsolescence.

A paracasting model for concurrent access to replicated content

We propose a framework to study how to download effectively a copy of the same document from a set of replicated servers. A generalized application-layer anycasting, known as paracasting, has been proposed to advocate concurrent access of a subset of replicated servers to satisfy cooperatively a client's request. Each participating server satisfies the request in part by transmitting a subset of the requested file to the client. The client can recover the complete file when different parts of the file sent from the participating servers are received. This framework allows us to estimate the average time to download a file from the set of homogeneous replicated servers, and the request blocking probability when each server can accept and serve a finite number of concurrent. requests. Our results show that the file download time drops when a request is served concurrently by a larger number of homogeneous replicated servers, although the performance improvement quickly saturates when the number of servers used increases. If the total number of requests that a server can handle simultaneously is finite, the request blocking probability increases with the number of replicated servers used to serve a request concurrently. Therefore, paracasting is effective in using a small number of servers, say, up to four, to serve a request concurrently.published_or_final_versio

A resequencing model for high speed networks

In this paper, we propose a framework to study the resequencing mechanism in high speed networks. This framework allows us to estimate the packet resequencing delay, the total packet delay, and the resequencing buffer occupancy distributions when data traffic is dispersed on multiple disjoint paths. In contrast to most of the existing work, the estimation of the end-to-end path delay distribution is decoupled from the queueing model for resequencing. This leads to a simple yet general model, which can be used with other measurement-based tools for estimating the end-to-end path delay distribution to find an optimal split of traffic. We consider a multiple-node M/M/1 tandem network as a path model. When end-to-end path delays are Gaussian distributed, our results show that the packet resequencing delay, the total packet delay, and the resequencing buffer occupancy drop when the traffic is spread over a larger number of homogeneous paths, although the network performance improvement quickly saturates when the number of paths used increases. We find that the number of paths used in multipath routing should be small, say up to three. Besides, an optimal split of traffic occurs at paths with equal loads.published_or_final_versio

Does it hurt when others prosper?: Exploring the impact of heterogeneous reordering robustness of TCP

The congestion control mechanisms in the standardized Transmission Control Protocol (TCP) may misinterpret packet reordering as congestive loss, leading to spurious congestion response and under-utilization of network capacity. Therefore, many TCP enhancements have been proposed to better differentiate between packet reordering and congestive loss, in order to enhance the reordering robustness (RR) of TCP. Since such enhancements are incrementally deployed, it is important to study the interactions of TCP flows with heterogeneous RR. This paper presents the first systematic study of such interactions by exploring how changing RR of TCP flows influences the bandwidth sharing among these flows. We define the quantified RR (QRR) of a TCP flow as the probability that packet reordering causes congestion response. We analyze the variation of bandwidth sharing as QRR changes. This leads to the discovery of several interesting properties. Most notably, we discover the counter-intuitive result that changing one flow's QRR does not affect its competing flows in certain network topologies. We further characterize the deviation, from the ideal case of bandwidth sharing, as RR changes. We find that enhancing RR of a flow may increase, rather than decrease, the deviation in some typical network scenarios. © 2013 IEEE.published_or_final_versio

Distributed opportunistic scheduling in multihop wireless ad hoc networks

In this paper, we introduce a framework for distributed opportunistic scheduling in multihop wireless ad hoc networks. With the proposed framework, one can take a scheduling algorithm originally designed for infrastructure-based wireless networks and adapt it to multihop ad hoc networks. The framework includes a wireless link state estimation mechanism, a medium access control (MAC) protocols and a MAC load control mechanism. The proposed link state estimation mechanism accounts for the latest results of packet transmissions on each wireless link. To improve robustness and provide service isolation during channel errors, the MAC protocol should not make any packet retransmissions but only report the transmission result to the scheduler. We modify IEEE 802.11 to fulfill these requirements. The MAC load control mechanism improves the system robustness. With link state information and the modified IEEE 802.11 MAC, we use BGFS-EBA, an opportunistic scheduling algorithm for infrastructured wireless networks, as an example to demonstrate how such an algorithm is converted into its distributed version within the proposed framework. The simulation results show that our proposed method can provide robust outcome fairness in the presence of channel errors. ©2008 IEEE.published_or_final_versio

Bandwidth-guaranteed fair scheduling with effective excess bandwidth allocation for wireless networks

Traffic scheduling is key to the provision of quality of service (QoS) differentiation and guarantees in wireless networks. Unlike its wireline counterpart, wireless communications pose special channel-specific problems such as time-varying link capacities and location-dependent errors. These problems make designing efficient and effective traffic scheduling algorithms for wireless networks very challenging. Although many wireless packet scheduling algorithms have been proposed in recent years, issues such as how to improve bandwidth efficiency and maintain goodput fairness with various link qualities for power-constrained mobile hosts remain unresolved. In this paper, we devise a simple wireless packet scheduling algorithm called bandwidth-guaranteed fair scheduling with effective excess bandwidth allocation (BGFS-EBA), which addresses these issues. Our studies reveal that BGFS-EBA effectively distributes excess bandwidth, strikes a balance between effort-fair and outcome-fair, and provides a delay bound for error-free flows and transmission effort guarantees for error-prone flows. © 2008 IEEE.published_or_final_versio

Communication-oriented smart grid framework

Upgrading the existing electricity grids into smart grids relies heavily on the development of information and communication technology which supports a highly reliable real-time monitoring and control system as well as coordination of various electricity utilities and market participants. In this upgrading process, smart grid communication is the key to success, and a simple but complete, innovative but compatible high-level communication-oriented smart grid framework is needed. This paper proposes a simple and flexible three-entity framework, so that devices employing the existing technologies are supported and can interoperate with those employing new technologies. © 2011 IEEE.published_or_final_versionThe 2nd IEEE International Conference on Smart Grid Communications (SmartGridComm 2011), Brussels, Belgium, 17-20 October 2011. In Proceedings of 2nd SmartGridComm, 2011, p. 61-6