14374205
Understanding Social Welfare Service Patterns Using Sequential Analysis
Classical exploratory data analysis methods in statistics and many of the earlier KDD methods tend to focus only on basic data types, (interval or categorical data) as the unit of analysis. However, some information cannot be interpreted unless the data is treated as a unit. For example, viewing the data as sequences of sets can reveal useful information that could not be extracted in any other way. Analyzing suitable databases from such a perspective can assist many social scientists in their work.
19868872
Management Assistance for Work First via a Dynamic Website
The purpose of the Work First project is to assist the state Dept. of Health and Human Services (DHHS) staff and each county Dept. of Social Services (DSS) across the state in the management of welfare reform initiatives. Work First is the cash assistance program in NC. One important objective is to encourage and support program managers to use data on outcomes to assess their performance. This is accomplished by providing them with easy to use and easy to understand comprehensive information on the experiences of families and individuals that have received assistance through their agency over time.
28890
Extension of Lower Probabilities and Coherence of Belief Measures
Coherence is an important concept which is introduced and discussed in a new mathematics branch, Imprecise Probability Theory. By using the Choquet integral, belief measures can be extended to be coherent lower previsions on the linear space consisting of all bounded functions. As a special case, we establish that all belief measures are coherent imprecise probabilities.
62615149
Mining Asynchronous Periodic Patterns in Time Series Data
Periodicy detection in time series data is a challenging problem of great importance in many applications. Most previous work focused on mining synchronous periodic patterns and did not recognize the misaligned presence of a pattern due to the intervention of random noise. In this paper, we propose a more flexible model of asynchronous periodic pattern that may be present only within a subsequence and whose occurrences may be shifted due to disturbance. Two parameters min/spl I.bar/rep and max/spl I.bar/dis are employed to specify the minimum number of repetitions that is required within each segment of nondisrupted pattern occurrences and the maximum allowed disturbance between any two successive valid segments. Upon satisfying these two requirements, the longest valid subsequence of a pattern is returned. A two-phase algorithm is devised to first generate potential periods by distance-based pruning followed by an iterative procedure to derive and validate candidate patterns and locate the longest valid subsequence. We also show that this algorithm cannot only provide linear time complexity with respect to the length of the sequence but also achieve space efficiency.
14969897
Dynamic adaptive file management in a local area network
In light of advances in processor and networking technology, especially the emergence of network attached disks, the traditional client-server architecture of file systems has become suboptimal for many computation/data intensive applications. We introduce a revised architecture for file management employing network attached storage: the dynamic file server environment (Dynamo). Dynamo introduces two main architectural innovations: to provide high scalability, the file management functions are mainly performed cooperatively by the clients in the system. Furthermore, data is transferred directly to the client's cache from network-attached disks, thus avoiding copies from a disk to the server buffer and then over the network to the client. Secondly, Dynamo uses a cooperative cache management which employs a decentralized lottery-based page replacement strategy. We show via performance benchmarks run on the Dynamo system and simulation results how this architecture increases the system's adaptability, scalability and cost performance.
11841640
Accelerating Profile Queries in Elevation Maps
Elevation maps are a widely used spatial data representation in geographical information systems (GIS). Paths on elevation maps can be characterized by profiles, which describe relative elevation as a function of distance. In this research, we address the inverse of this mapping - given a profile, how to efficiently find paths that could have generated it. This is called the profile query problem. Profiles have a wide variety of uses that include registering tracking information, or even other maps, to a given map. We describe a probabilistic model to characterize the maximal likelihood that a point lying on a path matches the query profile. Propagation of such probabilities to neighboring points can effectively prune the search space. This model enables us to efficiently answer queries of arbitrary profiles with user-specified error tolerances. When compared to existing spatial index methods, our approach supports more flexible queries with orders of magnitude speedup.
12623712
A transparent rate adaptation algorithm for streaming video over the Internet
The lack of end-to-end quality of service support in the current Internet has caused significant difficulties to ensuring playback continuity in video streaming applications. This study addresses this challenge by investigating a new adaptation algorithm to adjust the bit-rate of video data in response to the network bandwidth available to improve playback continuity. Unlike previous works, the proposed algorithm is transparent to the video client, requires no parameter tuning, and yet can outperform existing algorithms. This paper presents this algorithm, evaluates and compares its performance with the best algorithm currently available using extensive trace-driven simulations.
20701407
A General Structure of Feedback Shift Registers for Built-In Self Test
A mixed-type feedback shift register (MFSR) is simi lar to a linear feedback shift register (LFSR) except that the connection between two consecutive flip-flops (F/F's) may be through the Q or output, and an extra inver ter may exist at the input to the first flip-flop (stage) of the register. In this p aper, we exploit the properties of MFSR's and show that by using an MFSR based pseudorandom pattern generator (PRPG) or multiple input signature analyzer (MISA), several good features for built-in self test can be obtained. Specifically w e show that: (1) for any given initial seed, an MFSR always exists that can generate the s ame serial output sequence as can an LFSR with the same characteristic polynomial and any initial seed; (2) for any MFSR, we can always find an initial seed for this M FSR such that it can generate the same serial output sequence as can an LFSR with the same characteristic polynomial and any initial seed; and (3) for any given initial seed and any test response to be compressed, an MFSR based MISA can usually be found that will result in any required final signature. If such an MFSR cannot b e found for a specific initial seed and a specific test response sequence, we show that by simply adding one arbitrary dummy pattern to the test response, one can always find the required MFSR. We also show that if the characteristic polynomial of the MFSR based MISA can be chosen freely, it is almost guaranteed that a feasi ble MFSR can be found without adding any dummy patterns to the test response. Fo r example, for a 16-stage MISA, the probability that a feasible MFSR does not exist is less than 2-32768.
62579240
A Selective Rendering Method for Data Visualization
Author(s): Wang, Wencheng; Wu, En-Hua; Max, Nelson | Abstract: Selective visualization is a solution for visualizing data of large size and dimensionality. In this paper a new method is proposed for effectively rendering certain chosen parts among the full set of data in terms of a colour buffer, referred to as the virtual plane, for storing intermediate results. By this method, scientists may concentrate their attention on the contents of data in which they are interested. Besides, the method could be easily integrated with all the current direct volume rendering techniques, especially progressive refinement methods and selective methods.
6050292
Labeling Planar Graphs with Conditions on Girth and Distance Two
For a planar graph $G$, let $\Delta(G)$, $g(G)$, and $\lambda(G;p,q)$ denote, respectively, its maximum degree, girth, and $L(p,q)$-labeling number. We prove that (1) $\lambda(G;p,q)\le (2q-1)\Delta(G)+4p+4q-4$ if $g(G)\ge 7$; (2) $\lambda(G;p,q)\le (2q-1)\Delta(G)+6p+12q-9$ if $g(G)\ge 6$; (3) $\lambda(G;p,q)\le (2q-1)\Delta(G)+6p+24q-15$ if $g(G)\ge 5$. These bounds have consequences on conjectures by Wegner [Graphs with Given Diameter and a Coloring Problem, preprint, University of Dortmund, Dortmund, Germany, 1977] and Griggs and Yeh [SIAM J. Discrete Math., 5 (1992), pp. 586--595].
35803772
Approximate range–sum query answering on data cubes with probabilistic guarantees
Approximate range aggregate queries are one of the most frequent and useful kinds of queries for Decision Support Systems (DSS), as they are widely used in many data analysis tasks. Traditionally, sampling-based techniques have been proposed to tackle this problem. However, their effectiveness degrade when the underlying data distribution is skewed. Another approach based on the outlier management can limit the effect of data skews but fails to address other requirements of approximate range aggregate queries, such as error guarantees and query processing efficiency. In this paper, we present a technique that provides approximate answers to range aggregate queries on OLAP data cubes efficiently, with theoretical guarantees on the errors. Our basic idea is to build different data structures to manage outliers and the rest of the data. Carefully chosen outliers are organized in a quad-tree based indexing data structure to provide efficient access for query processing. A query-workload adaptive, tree-like synopsis data structure, called TunablePartition-Tree (TP-Tree), is proposed to organize samples extracted from non-outlier data. Our experiments clearly demonstrate the merits of our technique, by comparing with previous well-known techniques.