16132278
A constant factor approximation algorithm for k-median clustering with outliers
We consider the k-median clustering with outliers problem: Given a finite point set in a metric space and parameters k and m, we want to remove m points (called outliers), such that the cost of the optimal k-median clustering of the remaining points is minimized. We present the first polynomial time constant factor approximation algorithm for this problem.
618005
Online conflict-free coloring for halfplanes, congruent disks, and axis-parallel rectangles
We present randomized algorithms for online conflict-free coloring (CF in short) of points in the plane, with respect to halfplanes, congruent disks, and nearly-equal axis-parallel rectangles. In all three cases, the coloring algorithms use O(log n) colors, with high probability.
 We also present a deterministic algorithm for online CF coloring of points in the plane with respect to nearly-equal axis-parallel rectangles, using O(log3n) colors. This is the first efficient (i.e, using polylog(n) colors) deterministic online CF coloring algorithm for this problem.
14878951
The orienteering problem in the plane revisited
We consider the <i>orienteering problem</i>: Given a set <i>P</i> of <i>n</i> points in the plane, a starting point <i>r</i> ∈ <i>P</i>, and a length constraint <i>B</i>, one needs to find a tour starting at <i>r</i> that visits as many points of <i>P</i> as possible and of length not exceeding <i>B</i>. We present a (1−ε)-approximation algorithm for this problem that runs in <i>n</i><sup><i>O</i>(1/ε)</sup> time, and visits at least (1−ε)<i>k</i><sub>opt</sub> points of <i>P</i>, where <i>k</i><sub>opt</sub> is the number of points visited by the optimal solution. This is the first polynomial time approximation scheme (PTAS) for this problem. The algorithm also works in higher dimensions.
16063876
How to play a coloring game against a color-blind adversary
We study the problem of conflict-free (CF) coloring of a set of points in the plane, in an online fashion, with respect to halfplanes, nearly-equal axis-parallel rectangles, and congruent disks. As a warm-up exercise, the online CF coloring of points on the line with respect to intervals is also considered. We present randomized algorithms in the oblivious adversary model, where the adversary does not see the colors used. For the problems considered, the algorithms always produce valid CF colorings, and use O(logn) colors with high probability (these bounds are optimal in the worst case). Our randomized online algorithms are considerably simpler than previous algorithms for this problem and use fewer colors.We also present a deterministic algorithm for the CF coloring of points in the plane with respect to nearly-equal axis-parallel rectangles, using O(polylog(n)) colors. This is the first efficient deterministic online CF coloring algorithm for this problem.
16722943
The Euclidean Orienteering Problem Revisited
We consider the rooted orienteering problem: Given a set $P$ of $n$ points in the plane, a starting point $r \in P$, and a length constraint $B$, one needs to find a path starting from $r$ that visits as many points of $P$ as possible and of length not exceeding $B$. We present a $(1-\varepsilon)$-approximation algorithm for this problem that runs in $n^{O(1/\varepsilon)}$ time; the computed path visits at least $ (1-\varepsilon)k_{\mathrm{opt}}$ points of $P$, where $k_{\mathrm{opt}}$ is the number of points visited by an optimal solution. This is the first polynomial time approximation scheme for this problem. The algorithm also works in higher dimensions.
11635081
Cost-Aware Caching Algorithms for Distributed Storage Servers
We study replacement algorithms for non-uniform access caches that are used in distributed storage systems. Considering access latencies as major costs of data management in such a system, we show that the total cost of any replacement algorithm is bounded by the total costs of evicted blocks plus the total cost of the optimal off-line algorithm (OPT). We propose two off-line heuristics: MIN-d and MIN-cod, as well as an on-line algorithm: HD-cod, which can be run efficiently and perform well at the same time. 
 
Our simulation results with Storage Performance Council (SPC)'s storage server traces show that: (1) for off-line workloads, MIN-cod performs as well as OPT in some cases, all is atmost three times worse in all test case; (2) for on-line workloads, HD-cod performs closely to the best algorithms in all cases, and is the single algorithm that performs well in all test cases, including the optimal on-line algorithm (Landlord). Our study suggests that the essential issue to be considered be the trade-off between the costs of victim blocks and the total number of evictions in order to effectively optimize both efficiency and performance of distributed storage cache replacement algorithms.
33477464
Boundary-Based Feature Extraction and Recognition of Breast Tumors Using Support Vector Machine
19202214
A self-generating modular neural network architecture for supervised learning
Abstract In this paper, we present a self-generating modular neural network architecture for supervised learning. In the architecture, any kind of feedforward neural networks can be employed as component nets. For a given task, a tree-structured modular neural network is automatically generated with a growing algorithm by partitioning input space recursively to avoid the problem of pre-determined structure. Due to the principle of divide-and-conquer used in the proposed architecture, the modular neural network can yield both good performance and significantly faster training. The proposed architecture has been applied to several supervised learning tasks and has achieved satisfactory results.
3658125
PFRES: protein fold classification by using evolutionary information and predicted secondary structure
MOTIVATION
The number of protein families has been estimated to be as small as 1000. Recent study shows that the growth in discovery of novel structures that are deposited into PDB and the related rate of increase of SCOP categories are slowing down. This indicates that the protein structure space will be soon covered and thus we may be able to derive most of remaining structures by using the known folding patterns. Present tertiary structure prediction methods behave well when a homologous structure is predicted, but give poorer results when no homologous templates are available. At the same time, some proteins that share twilight-zone sequence identity can form similar folds. Therefore, determination of structural similarity without sequence similarity would be beneficial for prediction of tertiary structures.


RESULTS
The proposed PFRES method for automated protein fold classification from low identity (<35%) sequences obtains 66.4% and 68.4% accuracy for two test sets, respectively. PFRES obtains 6.3-12.4% higher accuracy than the existing methods. The prediction accuracy of PFRES is shown to be statistically significantly better than the accuracy of competing methods. Our method adopts a carefully designed, ensemble-based classifier, and a novel, compact and custom-designed feature representation that includes nearly 90% less features than the representation of the most accurate competing method (36 versus 283). The proposed representation combines evolutionary information by using the PSI-BLAST profile-based composition vector and information extracted from the secondary structure predicted with PSI-PRED.


AVAILABILITY
The method is freely available from the authors upon request.
15163337
A Database Encryption Scheme for Enhanced Security and Easy Sharing
Database encryption is a crucial technique in the security mechanisms of database. It is widely recognized as one of the key issues of data security. Current techniques of sharing the keys and the encrypted data for databases are neither convenient nor flexible in the real applications. Inspired by the PGP technique, we propose a novel database encryption scheme for enhanced data sharing inside a database, while preserving data privacy. It is characterized by both the fast speed of the conventional encryption and the convenience of key distribution of public key encryption. It also provides secured storage for security related data and effective key management, which enables the encrypted data to be shared conveniently. The scheme has been implemented and successfully applied on Oscar, a commercial DBMS developed by us
5116790
Flexible parallelization of fast wavelet transforms
In this paper, we present a new parallel algorithm for fast wavelet transforms (FWT) of a matrix of arbitrary size using any given number of parallel processors. The main idea in achieving the optimal load balancing is through a complexity analysis and flops minimization. This makes parallel implementation of FWT feasible and efficient on distributed memory machines with only a small number of processors and on local area networks. The new algorithm is tested by numerical experiments.