Search

Folders are a commonplace metaphor in computing environments, constituting a link to physical work materials and are a key means for individuals to impose order on their digital work materials. This paper presents the findings of a novel qualitative study examining folder use by 12 information workers, using logging to accurately capture how folders were used in individual everyday work over 6 weeks, and challenging participants to work without using folders. Through observation and interviews, the study provides new descriptions of how folders are used and the dependence some study participants had on their folders to think and create, as well as to access files. The findings call into question whether search and recency-based lists of files could fulfil the functional role of folders, identified as key means for individuals to construct and specialize their work environments. Implications are discussed for document management tools, and more generally for operating system design. [ABSTRACT FROM AUTHOR]

The main goal of this work was to experimentally verify the methods for a challenging task of categorization and clustering Polish text. Supervised and unsupervised learning was employed respectively for the categorization and clustering. A profound examination of the employed methods was done for the custom-built corpus of Polish texts. The corpus was assembled by the authors from Internet resources. The corpus data was acquired from the news portal and, therefore, it was sorted by type by journalists according to their specialization. The presented algorithms employ Vector Space Model (VSM) and TF-IDF (Term Frequency-Inverse Document Frequency) weighing scheme. Series of experiments were conducted that revealed certain properties of algorithms and their accuracy. The accuracy of algorithms was elaborated regarding their ability to match human arrangement of the documents by the topic. For both the categorization and clustering, the authors used F-measure to assess the quality of allocation. [ABSTRACT FROM AUTHOR]

Large-scale small file storage for original pages degrades performance of search engines. In this paper, we first analyze the disadvantages of the existing EXT3 file system in accessing small files. Then, the rate and speed of compression algorithms are verified to choose a proper storage compression algorithm. Meanwhile, we design an original page oriented file organization structure and a read-write query tree to store the large-scale small files which need no modification. The accessing response time and disk space waste are remarkably decreased when search engines use these techniques to store original-page small files. [ABSTRACT FROM AUTHOR]

Background: Single-molecule techniques have emerged as incisive approaches for addressing a wide range of questions arising in contemporary biological research [Trends Biochem Sci 38:30-37, 2013; Nat Rev Genet 14:9-22, 2013; Curr Opin Struct Biol 2014, 28C:112-121; Annu Rev Biophys 43:19-39, 2014]. The analysis and interpretation of raw single-molecule data benefits greatly from the ongoing development of sophisticated statistical analysis tools that enable accurate inference at the low signal-to-noise ratios frequently associated with these measurements. While a number of groups have released analysis toolkits as open source software [J Phys Chem B 114:5386-5403, 2010; Biophys J 79:1915-1927, 2000; Biophys J 91:1941-1951, 2006; Biophys J 79:1928-1944, 2000; Biophys J 86:4015-4029, 2004; Biophys J 97:3196-3205, 2009; PLoS One 7:e30024, 2012; BMC Bioinformatics 288 11(8):S2, 2010; Biophys J 106:1327-1337, 2014; Proc Int Conf Mach Learn 28:361-369, 2013], it remains difficult to compare analysis for experiments performed in different labs due to a lack of standardization. Results: Here we propose a standardized single-molecule dataset (SMD) file format. SMD is designed to accommodate a wide variety of computer programming languages, single-molecule techniques, and analysis strategies. To facilitate adoption of this format we have made two existing data analysis packages that are used for single-molecule analysis compatible with this format. Conclusion: Adoption of a common, standard data file format for sharing raw single-molecule data and analysis outcomes is a critical step for the emerging and powerful single-molecule field, which will benefit both sophisticated users and non-specialists by allowing standardized, transparent, and reproducible analysis practices. [ABSTRACT FROM AUTHOR]

The allocation algorithm of the Linux FAT32 file system driver positions files on disk in such a way that their relative positions reveal information on the order in which these files have been created. This provides an opportunity to enrich information from (carved) file fragments with time information, even when such file fragments lack the file system metadata in which time-related information is usually to be found. Through source code analysis and experiments the behaviour of the Linux FAT allocator is examined. How an understanding of this allocator can be applied in practice is demonstrated with a case study involving a TomTom GPS car navigation device. In this case, time information played a crucial role. Large amounts of location records could be carved from this device's flash storage, yielding insight into the locations the device has visited—yet the carved records themselves offered no information on when the device had been at the locations. Still, bounds on the records' time of creation could be inferred when making use of filesystem timestamps related to neighbouring on-disk positions. Finally, we perform experiments which contrast the Linux behaviour with that of Windows 7. We show that the latter differs subtly, breaking the strong relation between creation order and position. [ABSTRACT FROM AUTHOR]

Distributed metadata consistency is one of the critical issues of metadata clusters in distributed file systems. Existing methods to maintain metadata consistency generally need several log forced write operations. Since synchronous disk IO is very inefficient, the average response time of metadata operations is greatly increased. In this paper, an asynchronous atomic commit protocol (ACP) named Dual-Log (DL) is presented. It does not need any log forced write operations. Optimizing for distributed metadata operations involving only two metadata servers, DL mutually records the redo log in counterpart metadata servers by transferring through the low latency network. A crashed metadata server can redo the metadata operation with the redundant redo log. Since the latency of the network is much lower than the latency of disk IO, DL can improve the performance of distributed metadata service significantly. The prototype of DL is implemented based on local journal. The performance is tested by comparing with two widely used protocols, EP and S2PC-MP, and the results show that the average response time of distributed metadata operations is reduced by about 40%~60%, and the recovery time is only 1 second under 10 thousands uncompleted distributed metadata operations. [ABSTRACT FROM AUTHOR]

Federated, secure, standardized, scalable, and transparent mechanism to access and share resources, particularly data resources, across organizational boundaries that does not require application modification and does not disrupt existing data access patterns has been needed for some time in the computational science community. The Global Federated File System (GFFS) addresses this need and is a foundational component of the NSF-funded eXtreme Science and Engineering Discovery Environment (XSEDE) program. The GFFS allows user applications to access (create, read, update, delete) remote resources in a location-transparent fashion. Existing applications, whether they are statically linked binaries, dynamically linked binaries, or scripts (shell, PERL, Python), can access resources anywhere in the GFFS without modification (subject to access control). In this paper we present an overview of the GFFS and its most common use cases: accessing data at an NSF center from a home or campus, accessing data on a campus machine from an NSF center, directly sharing data with a collaborator at another institution, accessing remote computing resources, and interacting with remote running jobs. We present these uses cases and how they are realized using the GFFS. [ABSTRACT FROM AUTHOR]

File carving is a method that recovers files at unallocated space without any file information and used to recover data and execute a digital forensic investigation. In general, the file carving recovers files using the inherent header and footer in files or the entire file size determined in the file header. The largely used multimedia files, such as AVI, WAV, and MP3, can be exactly recovered using an internal format in files as they are continuously allocated. In the case of the NTFS, which is one of the most widely used file system, it supports an internal data compression function itself, but the NTFS compression function has not been considered in file carving. Thus, a large part of file carving tools cannot recover NTFS compressed files. Also, for carving the multimedia files compressed by the NTFS, a recovery method for such NTFS compressed files is required. In this study, we propose a carving method for multimedia files and represent a recovery plan for deleted NTFS compressed files. In addition, we propose a way to apply such a recovery method to the carving of multimedia files. [ABSTRACT FROM AUTHOR]

Peer-to-Peer (P2P) traffic has increased rapidly over the past few years, with file sharing providing the main drive behind such traffic. In this work we perform a measurement study of the content shared over the popular BitTorrent P2P file sharing network. We mathematically model the file size distributions of shared files after categorizing them into Audio, Video, Archive and CD image classes. For each of these categories we look into the most popular shared file formats and investigate their file size statistics. This provides an important milestone to building a realistic simulation framework for P2P systems, and for future analytical modeling of P2P networks. [ABSTRACT FROM AUTHOR]

Background: The Portable Document Format (PDF) is the most commonly used file format for online scientific publications. The absence of effective means to extract text from these PDF files in a layout-aware manner presents a significant challenge for developers of biomedical text mining or biocuration informatics systems that use published literature as an information source. In this paper we introduce the 'Layout-Aware PDF Text Extraction' (LA-PDFText) system to facilitate accurate extraction of text from PDF files of research articles for use in text mining applications. Results: Our paper describes the construction and performance of an open source system that extracts text blocks from PDF-formatted full-text research articles and classifies them into logical units based on rules that characterize specific sections. The LA-PDFText system focuses only on the textual content of the research articles and is meant as a baseline for further experiments into more advanced extraction methods that handle multi-modal content, such as images and graphs. The system works in a three-stage process: (1) Detecting contiguous text blocks using spatial layout processing to locate and identify blocks of contiguous text, (2) Classifying text blocks into rhetorical categories using a rule-based method and (3) Stitching classified text blocks together in the correct order resulting in the extraction of text from section-wise grouped blocks. We show that our system can identify text blocks and classify them into rhetorical categories with Precision1 = 0.96% Recall = 0.89% and F1 = 0.91%. We also present an evaluation of the accuracy of the block detection algorithm used in step 2. Additionally, we have compared the accuracy of the text extracted by LA-PDFText to the text from the Open Access subset of PubMed Central. We then compared this accuracy with that of the text extracted by the PDF2Text system, 2commonly used to extract text from PDF. Finally, we discuss preliminary error analysis for our system and identify further areas of improvement.Conclusions: LA-PDFText is an open-source tool for accurately extracting text from full-text scientific articles. The release of the system is available at http://code.google.com/p/lapdftext/. [ABSTRACT FROM AUTHOR]

Abstract: As systems provide more resources and host an indefinitely growing number of cores, the amount of data produced by simulation codes is steadily increasing, creating a bottleneck at the point where the data must be transferred to post processing software. One solution is to avoid the use of a file system altogether and couple post processing software directly to the simulation using an interface common to both sides of the transfer. HDF5, the widely known IO library, offers a modular mapping of file contents to storage, allowing the user to use different methods (drivers) for reading and writing data. These drivers are organized in a Virtual File Layer (VFL) so that the user can easily switch between – and if necessary – extend them. In order to be able to visualize and analyze data in-situ, we developed a parallel virtual file driver called the DSM driver, which allows the transfer of data in parallel between two different codes using only the HDF5 API; this driver has now been extended to support remote memory access operations. Whilst the original implementation allows one to post-process data in-situ, we present in this paper extensions to the driver that provide the ability to couple parallel applications bidirectionally. We use this to perform computational steering of simulations. Commands and data are sent back to the simulation using either the driver layer itself (primarily commands) or the HDF5 layer via the DSM driver (datasets). The use of HDF5 datasets for transfer between codes makes true parallel coupling possible, even when the data models of the codes are not directly compatible. The steering interface presented here is shown implemented within ParaView, the parallel visualization application, but the API is generic and in fact any applications that make use of HDF5 may be connected using the driver. [Copyright &y& Elsevier]

PCFS (Autonomous and Parallel Compressed File System) is a file system that supports fast autonomous compression at high compression rates. It is designed as a virtual layer inserted over existing file system, compressing and decompressing data by intercepting kernel calls. The system achieves enhanced compression ratio by combining two compression techniques. Speed is attained by performing the two compression techniques in parallel. Experimental results indicate good performance. [ABSTRACT FROM AUTHOR]

The recent proliferation of high-resolution mass spectrometers has generated a wealth of new data analysis methods. However, flexible integration of these methods into configurations best suited to the research question is hampered by heterogeneous file formats and monolithic software development. The mzXML, mzData, and mzML file formats have enabled uniform access to unprocessed raw data. In this paper we present our efforts to produce an equally simple and powerful format, PeakML, to uniformly exchange processed intermediary and result data. To demonstrate the versatility of PeakML, we have developed an open source Java toolkit for processing, filtering, and annotating mass spectra in a customizable pipeline (mzMatch), as well as a user-friendly data visualization environment (PeakML Viewer). The PeakML format in particular enables the flexible exchange of processed data between software created by different groups or companies, as we illustrate by providing a PeakML-based integration of the widely used XCMS package with mzMatch data processing tools. As an added advantage, downstream analysis can benefit from direct access to the full mass trace information underlying summarized mass spectrometry results, providing the user with the means to rapidly verify results. The PeakML/mzMatch software is freely available at http://mzmatch.sourceforge.net, with documentation, tutorials, and a community forum. [ABSTRACT FROM AUTHOR]

The need for efficient organization of files grows with the computer storage capabilities. However, a classical hierarchical file system offers little help in this matter, excepting maybe the case of links and shortcuts. OrcFS proposes a solution to this problem. By redefining several file system concepts, it allows the user to set custom metadata, in the form of “(property, value)” pairs, to express relationships between files. Using it, the system automatically creates a classified view of its components, in which those having similar characteristics are grouped together. A virtual hierarchy is generated, which provides multiple access paths to the same file. This assures that the data can be classified in a more flexible way and the navigation can be done more intuitively. The traditional concept of directory is extended, to accommodate the user-defined properties. In OrcFS, both classical navigation and query interrogation are possible. The enhanced system is compliant with the Linux’s VFS interface, thus no changes need to be made to existing applications and they may be used in OrcFS. A prototype of the project was implemented in user-space using the FUSE library to reimplement system calls. The performed tests proved that even if introducing new data in the OrcFS implies some overhead, this is negligible compared with the gain obtained when searching for files in an immense file tree structure. [ABSTRACT FROM AUTHOR]

The article offers brief information on the Open Biomedical Ontologies (OBO) Foundry, a collection of freely available ontologically structured controlled vocabularies in the biomedical domain. It states that most of this collection published through the OBO file format and Web Ontology Language (OWL), the semantic web format. It states that the current OWL of OBL Foundry ontologies contains numerous assertions which doesn't properly describes the biological realities.

Qualitative research is a heterogeneous field comprised of different and sometimes competing analytical strategies. A growing number of researchers use computer programs to assist in the analysis of qualitative data. Some analytical tasks are common ground and will be performed by most researchers regardless of their methodological approach. Software vendors try to accommodate an increasing demand for common and specific analytical needs and include an ever growing number of features in their products. Depending on the methodological point of departure, some functions provided in the current generation of CAQDAS packages may appear controversial because they invite the user to exceed the limits for the conclusions which can be drawn from qualitative analysis. In this article the limits for drawing conclusions from qualitative data are discussed from a social constructivist, discourse analytical perspective. This is described with the concept of qualitative syllogism logic. Some tools provided by CAQDAS packages are used in most qualitative methodological frameworks. These are discussed before two CAQDAS packages, NVivo 8 and MAXQDA 10, are compared with regard to how intuitively they provide these basic tools along with those that appear controversial because they exceed the limits of qualitative syllogism logic. [ABSTRACT FROM AUTHOR]

Abstract: This paper investigates the possibility of using web services as the building blocks for distributed file system, instead of the traditional RPC or RMI. [ABSTRACT FROM AUTHOR]

A Grid computing environment allows forming Virtual Organizations (VOs) to aggregate and share resources. We present a VO File System (VOFS) which is a secure VO-aware distributed file system that allows VO members to share files within a VO. VOFS supports access and location transparency by maintaining a common file namespace, which is decentralized to avoid a single point of failure in order to improve robustness of the file system. VOFS includes a P2P system of file servers, a VO membership service and a policy and role based security mechanism that protects the VO files from unauthorized access. VOFS can be mounted to a local file system in order to access files using a standard POSIX file API. VOFS can operate in a dynamic Grid environment (e.g. desktop Grids) since it is able to tolerate unplanned resource arrival and departure (churn) while maintaining a single uniform namespace. It supports transparent disconnected operations that allow the user to work on cached files while being disconnected. Furthermore, VOFS is a user level technique, and the current WebDAV-based VOFS prototype can operate under any operating system that has WebDAV mount support. [ABSTRACT FROM AUTHOR]

The article presents a research on a novel design for the implementation and evaluation of an ad-hoc parallel I/O system (AHPIOS). The research uses the configuration of the Message Passing Interface (MPI) and a storage management system that provides a tight integration of the integration of layers. It concludes that the AHPIOS parallel I/O system allows a high-performance parallel I/O that can be a cost-efficient alternative to conventional parallel file systems.

In this paper, we present an approach to interactive out-of-core volume data exploration that has been developed to augment the existing capabilities of the LhpBuilder software, a core component of the European project LHDL (). The requirements relate to importing, accessing, visualizing and extracting a part of a very large volume dataset by interactive visual exploration. Such datasets contain billions of voxels and, therefore, several gigabytes are required just to store them, which quickly surpass the virtual address limit of current 32-bit PC platforms. We have implemented a hierarchical, bricked, partition-based, out-of-core strategy to balance the usage of main and external memories. A new indexing scheme is introduced, which permits the use of a multiresolution bricked volume layout with minimum overhead and also supports fast data compression. Using the hierarchy constructed in a pre-processing step, we generate a coarse approximation that provides a preview using direct volume visualization for large-scale datasets. A user can interactively explore the dataset by specifying a region of interest (ROI), which further generates a much more accurate data representation inside the ROI. If even more precise accuracy is needed inside the ROI, nested ROIs are used. The software has been constructed using the Multimod Application Framework, a VTK-based system; however, the approach can be adopted for the other systems in a straightforward way. Experimental results show that the user can interactively explore large volume datasets such as the Visible Human Male/Female (with file sizes of 3.15/12.03 GB, respectively) on a commodity graphics platform, with ease. [ABSTRACT FROM AUTHOR]

The problem of statically assigning nonpartitioned files in a parallel I/O system has been extensively investigated. A basic workload characteristic assumption of most existing solutions to the problem is that there exists a strong inverse correlation between file access frequency and file size. In other words, the most popular files are typically small in size, while the large files are relatively unpopular. Recent studies on the characteristics of Web proxy traces suggested, however, the correlation, if any, is so weak that it can be ignored. Hence, the following two questions arise naturally. First, can existing algorithms still perform well when the workload assumption does not hold? Second, if not, can one develop a new file assignment strategy that is immune to the workload assumption? To answer these questions, we first evaluate the performance of three well-known file assignment algorithms with and without the workload assumption, respectively. Next, we develop a novel static nonpartitioned file assignment strategy for parallel I/O systems, called static round-robin (SOR), which is immune to the workload assumption. Comprehensive experimental results show that SOR consistently improves the performance in terms of mean response time over the existing schemes. [ABSTRACT FROM AUTHOR]

We investigate proof rules for information hiding, using the formalism of separation logic. In essence, we use the separating conjunction to partition the internal resources of a module from those accessed by the module's clients. The use of a logical connective gives rise to a form of dynamic partitioning, where we track the transfer of ownership of portions of heap storage between program components. It also enables us to enforce separation in the presence of mutable data structures with embedded addresses that may be aliased. [ABSTRACT FROM AUTHOR]

Abstract: Portable Document Format (PDF) developed by Adobe Systems Inc. is a flexible and popular document distribution and delivery file format, and it is supported within various operating systems and devices. This article provides insight for some of the security issues within the format itself as well as an outlook of the vulnerabilities found from various versions of Adobe‘s own PDF viewer implementation. [Copyright &y& Elsevier]

In flash memory-based storage, a Flash Translation Layer (FTL) manages the mapping between the logical addresses of a file system and the physical addresses of the flash memory. When a journaling file system is set up on the FTL, the consistency of the file system is guaranteed by duplications of the same file system changes in both the journal region of the file system and the home locations of the changes. However, these duplications inevitably degrade the performance of the file system. In this article we present an efficient FTL, called JFTL, based on a journal remapping technique. The FTL uses an address mapping method to write all the data to a new region in a process known as an out-of-place update. Because of this process, the existing data in flash memory is not overwritten by such an update. By using this characteristic of the FTL, the JFTL remaps addresses of the logged file system changes to addresses of the home locations of the changes, instead of writing the changes once more to flash memory. Thus, the JFTL efficiently eliminates redundant data in the flash memory as well as preserving the consistency of the journaling file system. Our experiments confirm that, when associated with a writeback or ordered mode of a conventional EXT3 file system, the JFTL enhances the performance of EXT3 by up to 20%. Furthermore, when the JFTL operates with a journaled mode of EXT3, there is almost a twofold performance gain in many cases. Moreover, the recovery performance of the JFTL is much better than that of the FTL. [ABSTRACT FROM AUTHOR]

DSDP implements the dual-scaling algorithm for semidefinite programming. The source code for this interior-point algorithm, written entirely in ANSI C, is freely available under an open source license. The solver can be used as a subroutine library, as a function within the Matlab environment, or as an executable that reads and writes to data files. Initiated in 1997, DSDP has developed into an efficient and robust general-purpose solver for semidefinite programming. Its features include a convergence proof with polynomially bounded worst-case complexity, primal and dual feasible solutions when they exist, certificates of infeasibility when solutions do not exist, initial points that can be feasible or infeasible, relatively low memory requirements for an interior-point method, sparse and low-rank data structures, extensibility that allows applications to customize the solver and improve its performance, a subroutine library that enables it to be linked to larger applications, scalable performance for large problems on parallel architectures, and a well-documented interface and examples of its use. The package has been used in many applications and tested for efficiency, robustness, and ease of use. [ABSTRACT FROM AUTHOR]

In digital forensics, the first step to conducting an investigation is to acquire evidence that is most related to the case. Containing most recently accessed data and information about the status of a system, physical memory is a valuable source of digital evidence. When a process runs or accesses a file, all or some parts of the process's executable or accessed data file are mapped into the physical memory. In this article, we propose various methods to find files and extract them from memory in order to rebuild executable and data files that existed in physical memory at the time of incident. We developed a memory analysis plug-in that uses this automated memory file extraction. Using this tool, we have been able to extract a wide range of data file types, including text, PDF, Java Archives (JAR), various logs, EVT (system event-log files, used by the system event viewer), HTML and many more. Investigators can use the result of this research in order to (1) compare the files found on disk with those extracted from memory to find possible tampering or (2) reconstruct those files that no longer exist on the disk. In addition, they can find the last file modifications that have not been mapped out to the corresponding files on the disk. Memory extracted files can be used for the purpose of correlation analysis along with other sources of evidence such as application or network log files, E-mail files, and data files found on disks. [ABSTRACT FROM AUTHOR]

We observe that an effect of "disk resource sharing" of multi-copy movie traffic has great impact on the blocking performance of a video-on-demand system. This observation leads us to establish a conjecture on how to balance the movie traffic load among "combination" groups of disks to maximize the level of disk resource sharing. For a given file replication instance, the conjecture predicts in general an effective lower bound on the blocking performance of the system. It motivates the design of a numerical index that measures quantitatively the goodness of disk resource sharing on allocation of multi-copy movie files. It also motivates the design of a greedy file allocation method that decides a good quality heuristic solution for each feasible file replication instance. We further develop analytical formulas to obtain approximate results for the bound fast and accurately. These techniques can be utilized by an optimization program to find near-optimal file assignment solutions for the system computationally efficiently. [ABSTRACT FROM AUTHOR]

Abstract: This paper suggests a novel compression scheme for small text files. The proposed scheme depends on Boolean minimization of binary data accompanied with the adoption of Burrows-Wheeler transformation (BWT) algorithm. Compression of small text files must fulfil special requirements since they have small context. The use of Boolean minimization and Burrows-Wheeler transformation generate better context information for compression with standard algorithms. We tested the suggested scheme on collections of small and medium-sized files. The testing results showed that proposed scheme improve the compression ratio over other existing methods. [Copyright &y& Elsevier]

We present the Network File System with Cluster Delegation (NFS-CD), an enhancement to the NFSv4 that reduces server load and increases the scalability of distributed file systems in computing clusters. The cluster delegation feature of NFS-CD allows data sharing among clients by extending the NFSv4 delegation model so that multiple clients manage a single file without interacting with theserver. Based on cluster delegation, we implement a fast-commit primitive, cooperative caching, and the ability to recover the uncommitted updates of a failed computer. NFS-CD supports both read and write operations in the cooperative cache without degrading the consistency model of NFSv4. We have implemented NFS-CD by modifying the Linux NFSv4 client only. Because the server remains unchanged, NFS-CD preserves the simple administration model of NFSv4 and interoperates with standard NFS clients. NFS-CD offers improved performance when compared to NFSv4 at the expense of slightly weaker reliability guarantees. An experimental evaluation of our implementation, using industry standard benchmarks and application workloads, reveals that NFS-CD reduces server load by more than half. It also demonstrates that under most workloads, file systems must support writes to the cooperative cache to achieve scale. [ABSTRACT FROM AUTHOR]

Abstract: In contrast to regular queries that are evaluated only once, a continuous query remains active over a period of time and has to be continuously evaluated to provide up to date answers. We propose a method for continuous range query processing for different types of queries, characterized by mobility of objects and/or queries which all follow paths in an underlying spatial network. The method assumes an available 2D indexing scheme for indexing spatial network data. An appropriately extended R∗-tree, that primarily is used as an indexing scheme for network segments, provides matching of queries and objects according to their locations on the network or their network routes. The method introduces an additional pre-refinement step which generates main-memory data structures to support efficient, incremental reevaluation of continuous range queries in periodically performed refinement steps. [Copyright &y& Elsevier]

We introduce novel dissimilarity into a probabilistic clustering task to properly measure dissimilarity among multiple clusters when each cluster is characterized by a subpopulation in the mixture model. This measure of dissimilarity is called redundancy-based dissimilarity among probability distributions. From aspects of both source coding and a statistical hypothesis test, we shed light on several of the theoretical reasons for the redundancy-based dissimilarity among probability distributions being a reasonable measure of dissimilarity among clusters. We also elucidate a principle in common for the measures of redundancy-based dissimilarity and Ward's method in terms of hierarchical clustering criteria. Moreover, we show several related theorems that are significant for clustering tasks. In the experiments, properties of the measure of redundancy-based dissimilarity are examined in comparison with several other measures. [ABSTRACT FROM AUTHOR]

Hierarchical clustering is a stepwise clustering method usually based on proximity measures between objects or sets of objects from a given data set. The most common proximity measures are distance measures. The derived proximity matrices can be used to build graphs, which provide the basic structure for some clustering methods. We present here a new proximity matrix based on an entropic measure and also a clustering algorithm (LEGClust) that builds layers of subgraphs based on this matrix and uses them and a hierarchical agglomerative clustering technique to form the clusters. Our approach capitalizes on both a graph structure and a hierarchical construction. Moreover, by using entropy as a proximity measure, we are able, with no assumption about the cluster shapes, to capture the local structure of the data, forcing the clustering method to reflect this structure. We present several experiments on artificial and real data sets that provide evidence on the superior performance of this new algorithm when compared with competing ones. [ABSTRACT FROM AUTHOR]

The article discusses a way to improve accessibility to unstructured data. Unstructured data, such as that contained in spreadsheets and word processing documents, defies easy categorization. Yet it can be instrumental in mission-critical processes, and its volume continues to grow. File Area Networks (FANs) simplify managing unstructured data by maintaining a virtual presentation immune to the data's actual location. A FAN can be either software run by the hosts' CPU, or an appliance. FANs are efficient, scalable, and cost-effective, but complications may arise if a firm uses FANS from multiple vendors.

Background: As different tissue types have distinct capabilities to accumulate protoporphyrin-IX, fluorescence diagnosis with aminolevulinic acid-induced porphyrin (FDAP) could be used to discriminate between different tissue types.Objective: Protoporphyrin-IX accumulation and proliferation were studied in cutaneous squamous (pre)malignancies to see whether FDAP could be used to discriminate between different stages of keratinocytic intraepidermal neoplasia or proliferative status.Methods: FDAP was performed in 14 patients (86 lesions) and biopsy specimens were taken, on which (immuno)histochemistry was performed for histopathologic classification and assessment of Ki67-antigen expression. Stratum corneum thickness was also measured.Results: The fluorescence ratio (lesional:nonlesional skin) showed neither significant differences between the different keratinocytic intraepidermal neoplasia stages, nor between different levels of Ki67-antigen expression. Macroscopic fluorescence intensity and stratum corneum thickness were negatively correlated.Limitations: Relatively few malignancies were biopsied.Conclusions: With FDAP we were not able to discriminate between keratinocytic intraepidermal neoplasia lesions or proliferative activity. However, hyperkeratosis appeared to be an important determinant in variations in macroscopic fluorescence intensity. [ABSTRACT FROM AUTHOR]

Contributory applications allow users to donate unused resources on their personal computers to a shared pool. Applications such as SETI@home, Folding@home, and Freenet are now in wide use and provide a variety of services, including data processing and content distribution. However, while several research projects have proposed contributory applications that support peer-to-peer storage systems, their adoption has been comparatively limited. We believe that a key barrier to the adoption of contributory storage systems is that contributing a large quantity of local storage interferes with the principal user of the machine. To overcome this barrier, we introduce the Transparent File System (TFS). TFS provides background tasks with large amounts of unreliable storage-all of the currently available space-without impacting the performance of ordinary file access operations. We show that TFS allows a peer-to-peer contributory storage system to provide 40% more storage at twice the performance when compared to a user-space storage mechanism. We analyze the impact of TFS on replication in peer-to-peer storage systems and show that TFS does not appreciably increase the resources needed for file replication. [ABSTRACT FROM AUTHOR]

Producer 2003 is a free add-on tool for PowerPoint 2003. This software allows the user to import PowerPoint slides, video, slides, and images and then capture, synchronize, and publish other audio, to provide a completed rich-media presentation. Audio and video content can be either prerecorded or created within Producer as you create the presentation. Producer 2003 is ideally suited for secondary and post-secondary teachers and students, media professionals, training specialists, sales professionals, and anyone who wishes to create exciting presentations. When using producer, most users begin by creating a PowerPoint presentation containing all the text they would like to include in the project. Next, the PowerPoint file and other media files should be imported into Producer (remember, the user can also create audio and media files and import them to Producer). Finally, the user can either use a drag-and-drop timeline to arrange and synchronize the timing of all the elements. In addition producer has a "New Presentation Wizard" that guides the user through the entire process. Several available templates allow the user to select from predefined screen layouts to create an attractive interface if the final presentation is to be published to the Web. [ABSTRACT FROM AUTHOR]

To bound memory consumption, most compression systems provide a facility that controls the amount of data that may be processed at once—usually as a block size, but sometimes as a direct megabyte limit. In this work we consider the Re-Pair mechanism of Larsson and Moffat (2000), which processes large messages as disjoint blocks to limit memory consumption. We show that the blocks emitted by Re-Pair can be postprocessed to yield further savings, and describe techniques that allow files of 500 MB or more to be compressed in a holistic manner using less than that much main memory. The block merging process we describe has the additional advantage of allowing new text to be appended to the end of the compressed file. [ABSTRACT FROM AUTHOR]

Large scale scientific simulation codes typically run on a cluster of CPUs that write/read time steps to/from a single file system. As data sets are constantly growing in size, this increasingly leads to I/O bottlenecks. When the rate at which data is produced exceeds the available I/O bandwidth, the simulation stalls and the CPUs are idle. Data compression can alleviate this problem by using some CPU cycles to reduce the amount of data needed to be transfered. Most compression schemes, however, are designed to operate offline and seek to maximize compression, not throughput. Furthermore, they often require quantizing floating-point values onto a uniform integer grid, which disqualifies their use in applications where exact values must be retained. We propose a simple scheme for lossless, online compression of floating-point data that transparently integrates into the I/O of many applications. A plug-in scheme for data-dependent prediction makes our scheme applicable to a wide variety of data used in visualization, such as unstructured meshes, point sets, images, and voxel grids. We achieve state-of-the-art compression rates and speeds, the latter in part due to an improved entropy coder. We demonstrate that this significantly accelerates I/O throughput in real simulation runs. Unlike previous schemes, our method also adapts well to variable-precision floating-point and integer data. [ABSTRACT FROM AUTHOR]

The article focuses on a new Portable Document Format Enhancer (PDF E) software from Apago Inc. Dwight Kelly, president of the company provides an overview of the product. The company has been in the software development field for the last 15 years and has developed softwares for market giants like Fuji International, Screen Corp. Ltd., Hewlett-Packard Co. and Dupont. But the company is still struggling for a market image and name recognition. It is expected that new PDF E would give the company its long time recognition. PDF E is a stand alone product and does not need updates every time Adobe Systems Inc. updates its Acrobat reader. The product would be of great advantage to the printing industry. PDF E helps in repurposing PDF files. It checks the files, eliminates all redundancies, optimizes compression, analyses for problems and so on. It also fixes many fragmented PDF files. Finally, it generates a list of all the operations performed on the files. The article also provides detailed working of the system. INSET: Setting Up a New Target's Specifications..