Placement solutions for multiple versions of a multimedia object

Transcoding is an important technology which adapts the same multimedia object to diverse mobile appliances; thus, users' requests for a specified version of a multimedia object could be served by a more detailed version cached according to transcoding. Therefore, it is of particularly theoretical and practical necessity to determine the proper versions to be cached at a node such that the specified objective is achieved. In this paper, we address the problem of multimedia object placement. The performance objective is to minimize the total access cost by considering both transmission cost and transcoding cost. We present an optimal dynamic programming-based solution for this problem. The performance of the proposed solutions is evaluated with a set of carefully designed simulation experiments for various performance metrics over a wide range of system parameters. The simulation results show that our solution consistently and significantly outperforms comparison solutions in terms of all the performance metrics considered.Keqiu Li, Hong Shen, Francis Y. L. Chi

Protein mechanical unfolding: importance of non-native interactions

Mechanical unfolding of the fourth domain of Distyostelium discoideum filamin (DDFLN4) was studied by all-atom molecular dynamics simulations, using the GROMOS96 force field 43a1 and the simple point charge explicit water solvent. Our study reveals an important role of non-native interactions in the unfolding process. Namely, the existence of a peak centered at the end-to-end extension 22 nm in the force-extension curve, is associated with breaking of non-native hydrogen bonds. Such a peak has been observed in experiments but not in Go models, where non-native interactions are neglected. We predict that an additional peak occurs at 2 nm using not only GROMOS96 force field 43a1 but also Amber 94 and OPLS force fields. This result would stimulate further experimental studies on elastic properties of DDFLN4.Comment: 27 pages, 15 figure

Dynamical Effects from Asteroid Belts for Planetary Systems

The orbital evolution and stability of planetary systems with interaction from the belts is studied using the standard phase-plane analysis. In addition to the fixed point which corresponds to the Keplerian orbit, there are other fixed points around the inner and outer edges of the belt. Our results show that for the planets, the probability to move stably around the inner edge is larger than the one to move around the outer edge. It is also interesting that there is a limit cycle of semi-attractor for a particular case. Applying our results to the Solar System, we find that our results could provide a natural mechanism to do the orbit rearrangement for the larger Kuiper Belt Objects and thus successfully explain the absence of these objects beyond 50 AU.Comment: accepted by International Journal of Bifurcation and Chaos in Aug. 2003, AAS Latex, 27 pages with 6 color figure

On the Mass-Period Distributions and Correlations of Extrasolar Planets

In addition to fitting the data of 233 extra-solar planets with power laws, we construct a correlated mass-period distribution function of extrasolar planets, as the first time in this field. The algorithm to generate a pair of positively correlated beta-distributed random variables is introduced and used for the construction of correlated distribution functions. We investigate the mass-period correlations of extrasolar planets both in the linear and logarithm spaces, determine the confidence intervals of the correlation coefficients, and confirm that there is a positive mass-period correlation for the extrasolar planets. In addition to the paucity of massive close-in planets, which makes the main contribution on this correlation, there are other fine structures for the data in the mass-period plane.Comment: to be published in AJ, tentatively in December 200

Multimedia object placement for hybrid transparent data replication

In this paper, we address present an optimal solution for the problem of multimedia object placement for hybrid transparent data replication. The performance objective is to minimize the total access cost by considering both transmission cost and transcoding cost. The performance of the proposed solution is evaluated with a set of carefully designed simulation experiments for various performance metrics over a wide range of system parameters. The simulation results show that our solution consistently and significantly outperforms comparison solutions in terms of all the performance metrics considered. © 2005 IEEE.published_or_final_versio

Multimedia object placement for hybrid transparent data replication

© 2005 IEEEIn this paper, we address present an optimal solution for the problem of multimedia object placement for hybrid transparent data replication. The performance objective is to minimize the total access cost by considering both transmission cost and transcoding cost. The performance of the proposed solution is evaluated with a set of carefully designed simulation experiments for various performance metrics over a wide range of system parameters. The simulation results show that our solution consistently and significantly outperforms comparison solutions in terms of all the performance metrics considered

The impact of alerting design on air traffic controllers' response to conflict detection and resolution

Purposes: The research aim is to develop a better design of auditory alerts that can improve air traffic controllers’ situation awareness. Method: Participants are seventy-seven qualified Air Traffic Controllers. The experiment was conducted in the Air Traffic Control operational rooms of the Irish Aviation Authority at Shannon and Dublin. Participants were advised that the trials were in relation to the COOPANS Air Traffic Control. ANOVA with two between-subject factors (alerting designs and experience levels) were conducted to analyze the ATCO’s response time for three critical events. Bonferroni test was performed for post-hoc analysis on mean differences of response time. Results: There is a significant difference in ATCO’s response time between acoustic alert and semantic alert across STCA, APW and MSAW. No significant main effect of controllers’ experience on ATCO’s response time for STCA and APW. Also, there is no significant interaction between alerting design and experience level on ATCO’s response time across STCA, APW and MSAW. Conclusion: The results demonstrated that the acoustic alert deployed within the COOPANS ATM system provides level-1 Situational Awareness to ATCO’s compared with an semantic alert which provides not only level-1 of situational awareness for perceived alerts, but also level-2 and level-3 of situational awareness to assist ATCO understanding of critical events and therefore develop more suitable solutions. Consequently, human-centered design of a semantic alert can significantly speed up ATCO’s response to STCA, and APW. Furthermore, the sematic alert could alleviate expertise differences by promoting quicker response times for both novice and experienced air traffic controllers

Effect of lycium barbarum (wolfberry) polysaccharides on preserving retinal function after partial optic nerve transection

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