Video data storage policies: an access frequency based approach

Video applications are characterized by their increased requirements for huge storage spaces and timing synchronization. Video data storage is a critical issue due to the so-called I/O bottleneck problem in relation to the quality of service while accessing video applications. The main contribution of the paper is that it considers video data dependencies, access frequencies and timing constraints in order to introduce a video data representation model which guides the storage policies. Two video data representation levels are considered to capture the frequencies of accesses at external (video objects) and internal (video clips) levels. A simulation model has been developed in order to evaluate the placement strategies. Video data placement is performed on a tertiary storage subsystem by both constructive and iterative improvement policies. Iterative improvement placement has been proven to outperform the other video data placement approaches.     

Development of YBCO coatings by atmospheric plasma spraying

Superconducting Y–Ba–Cu–O thick films were produced by the atmospheric plasma spraying method. The effect of processing parameters (powder characteristics, spraying parameters) on the coatings properties was studied. X-ray diffraction analysis, SEM studies combined with EDS microanalysis and scratch test experiments were carried out in order to characterize the adhesion of the coatings to the substrate, the coatings morphology the thickness and crystalline structure as well as the powder phase transformations during spraying. For restoring the superconducting phase after deposition, the coatings were heated in oxygen in the temperature range 750–930°C. It was shown that the quality of the coatings and the adhesion to the substrate are greatly dependent on the deposition conditions. By calcining in oxygen under the appropriate conditions coatings consisting of the pure superconducting phase can be obtained.     

Effect of Slurry Rheological Properties on the Coating of Ceramic Honeycombs with Yttria-Stabilized-Zirconia Washcoats

Recently, a novel automotive catalyst design, based on the use of palladium supported on yttria-stabilized zirconia (YSZ), was proposed. In the present work, the coating of cordierite honeycomb samples with YSZ slurries for the preparation of such washcoats was investigated. The loading percentage, homogeneity, and reproducibility were found to depend strongly on the slurry viscosity. Parameters such as the slurry-solids content, pH, type of powder used, and use and quantity of the dispersants were optimized for the preparation of stable, low-viscosity YSZ slurries, adjustments that could lead to an efficient coating process for honeycomb structures.     

Indoor and outdoor personal exposure to benzene in Athens, Greece

OBJECTIVE: To evaluate the exposure of urban inhabitants to atmospheric benzene in Athens, Greece. METHODS: Fifty non-smoker volunteers from selected occupational groups and their homes were monitored by passive air samplers for six 5-day periods during a year. An activity diary was completed during each sampling period and relevant data were collected by a questionnaire at the beginning of the study. Additional data on urban levels on benzene were also available. RESULTS: Average benzene home and personal levels in six monitoring campaigns varied between 6.0-13.4 and 13.1-24.6 microg/m(3), respectively. Urban levels varied between 15.4 and 27.9 microg/m(3) with an annual mean of 20.4 microg/m(3). Wind speed seems to determine largely home levels and personal exposure. Proximity to busy road holds also an important influence on indoor benzene levels. Adjusted for seasonal or climate variation, other significant prognostic factors of personal exposure were home levels, total time spent outdoors and transportation mean. Time spent outdoors explains the strong relationship between occupation and personal levels of exposure. Wind had similar effect in clearing indoor and urban pollution in Athens; lessen personal exposure and home levels about 2-2.5 microg/m(3) per 1 m/s increase in speed. CONCLUSIONS: Factors related to climate (use of non-absorbent materials for wall and floor covering and frequent ventilation) might be one explanation for homes' high clearing rate. Our exposure pattern, which suggests that outdoors work give the greater contribution to benzene exposure of Athens citizens, is uncommon in northern towns of Europe. Policy makers have to take in account these differences in establishing guidelines for ambient benzene exposure.     

Integrating similarity and dissimilarity notions in recommenders

Collaborative recommenders rely on the assumption that similar users may exhibit similar tastes while content-based ones favour items that found to be similar with the items a user likes. Weak related entities, which are often considered to be useful, are neglected by those similarity-driven recommenders. To take advantage of this neglected information, we introduce a novel dissimilarity-based recommender that bases its estimations on degrees of dissimilarities among items’ attributes. However, instead of using the proposed recommender as a stand-alone method, we combine it with similarity-based ones to maintain the selective nature of the latter while detecting, through our recommender, information that may have been overlooked. Such combinations are established by IANOS, a proposed framework through which we increase the accuracy of two popular similarity-based recommenders (Naive Bayes and Slope-One) after their combination with our algorithm. Improved accuracy results in experimentation on two datasets (Yahoo! Movies and Movielens) enhance our reasoning. However, the proposed recommender comes with an additional computational complexity when combined with other techniques. By using Hadoop technology, we developed a distributed version of IANOS through which execution time was reduced. Evaluation on IANOS procedures in terms of time performance endorses the use of distributed implementations.     

Introduction to play therapy research theme issue.

Play therapy is at a point in its history where outside forces are demanding that we look at ourselves and demonstrate that what we do has empirical value. Many of these outside forces have either ignored play therapy or have questioned, even denied, the capacity of play therapy to produce positive outcomes in therapy and counseling of children. It is from this perspective that the need for a special research theme issue was born. Detractors and supporters of play therapy need to know what the state of the art is in play therapy research, along with ways we can help move play therapy research exposure and credibility forward. Sandra Frick-Helms was invited to guest edit this first in a series of theme issues for the International Journal of Play Therapy. She in turn asked Athena Drewes to join her in coediting this issue because of her wide range of knowledge, skill, and contacts in the therapy and counseling fields. Together, they have compiled an impressive grouping of authors and researchers who offer the reader food for thought and practical tips for research application. (PsycINFO Database Record (c) 2010 APA, all rights reserved)