A Digital Television Navigator

Digital television is a new, interesting, and rich platform for developing next generation multimedia services. Navigator is the most important service of digital television. It acts as the main index of all services available in set-top box. In this paper, we describe the definition of a Navigator, its functionality, its information retrieval processes, and its information source based on DVB-SI (Service Information) which is multiplexed in MPEG2 Transport Streams (TS). The process of developing a Navigator in Java language is presented. A software model including navigation model, state model of a remote control, and data structures is introduced. Furthermore, a software reference model for DVB-SI demultiplexing is described. Its implementation was based on a client/server approach using the User Datagram Protocol (UDP). The development issues, performance evaluation, and future research topics are given as conclusions.     

Approximation algorithms for optimization problems in graphs with superlogarithmic treewidth

We present a generic scheme for approximating NP-hard problems on graphs of treewidth k=ω(logn). When a tree-decomposition of width ? is given, the scheme typically yields an ?/logn-approximation factor; otherwise, an extra logk factor is incurred. Our method applies to several basic subgraph and partitioning problems, including the maximum independent set problem.     

Evaluating the expedited forwarding of voice traffic in a differentiated services network

The Differentiated Services architecture offers a scalable alternative to provide Quality of Service (QoS) to the new multimedia applications in the Internet. This paper aims at evaluating the delay and jitter experienced by voice traffic when handled by the Expedited Forwarding (EF) scheme. The analysis includes the effects of different packet scheduling mechanisms implementing EF and of the voice packet size. We also evaluate how efficiently each type of traffic uses an extra allocated bandwidth and the impact of traffic shaping. The results show that increasing the service rate share allocated to the EF aggregate does not significantly affect the competing best effort (BE) traffic. This holds as long as the BE traffic can use the bandwidth left unused by the EF traffic in idle periods. Copyright © 2002 John Wiley & Sons, Ltd.     

Characterization of Alq3 thin films by a near-field microwave microprobe

We observed tris-8-hydroxyquinoline aluminum (Alq3) thin films dependence on substrate heating temperatures by using a near-field microwave microprobe (NFMM) and by optical absorption at wavelengths between 200 and 900nm. The changes of absorption intensity at different substrate heating temperatures are correlated to the changes in the sheet resistance of Alq3 thin films.     

Tissue integrity,costs and time associated with different agents for histological bone preparation

The selection of an appropriate demineralizing solution in pathology laboratories depends on several factors such as the preservation of cellularity, urgency of diagnostic and financial costs. The aim of this study was to test different decalcification bone procedures in order to establish the best value of these in formalin‐fixed and paraffin‐embedded samples. Femurs were removed from 13 adult male Wistar rats to obtain 130 bone disks randomly divided into five groups that were demineralized in different concentrations of nitric acid (Group I); formic acid (Group II); acetic acid (Group III); EDTA, pH7.4 (Group IV) and Morsés solution (Group V). Serial, 3‐μm‐thick sections were obtained and stained with hematoxylin‐eosin to calculate the percentage of osteocyte‐occupied lacunae. The sections were also stained with Masson's trichrome in conjunction with picrosirius red under polarized light followed by a semi‐quantitative analysis to verify the adjacent muscle‐to‐bone integrity and preservation of collagen fibres. The highest percentage of osteocyte‐occupied lacunae was found with 10% acetic acid solution (95.64 ± 0.95%) and Group I (nitric acid) demanded the shorter time (0.8–5.7days). Of all solutions, 5% nitric acid incurred the lowest cost to achieve complete demineralization compared with other solutions (p < .001). Group IV (EDTA) had the highest integrity of muscle and collagen type I and III (P < 0.01). Demineralization with 10% acetic acid was the most effective at preserving bone tissue, while 5% EDTA was the best at maintaining collagen and adjacent muscle to bone. In conclusion, nitric acid at 5% showed the most efficient result as it balanced both time and cost as a demineralizing solution.     

Theoretical study of the human bradykinin-bradykinin B2 receptor complex

The interaction of bradykinin (BK) with the bradykinin B2 receptor (B2R) was analyzed by using molecular modeling (MM) and molecular dynamics (MD) simulations. A homology model for B2R has been generated and the recently determined receptor-bound solid-state NMR spectroscopic structure of BK (Lopez et al., Angew. Chem. 2008, 120, 1692-1695; Angew. Chem. Int. Ed. 2008, 47, 1668-1671) has been modeled into the binding pocket of the receptor to probe the putative ligand-receptor interface. The experimental hormone structure fitted well into the binding pocket of the receptor model and remained stable during the MD simulation. We propose a parallel orientation of the side chains for Arg1 and Arg9 in BK that is bound to B2R. The MD simulation study also allows the conformational changes that lead to the activated form of B2R to be analyzed. The hydrogen bond between N140 (3.35) and W283 (6.48) is the key interaction that keeps the receptor in its inactive form. This hydrogen bond is broken during the MD simulation due to rotation of transmembrane helix 3 (TM3) and is replaced by a new hydrogen bond between W283 (6.48) and N324 (7.45). We propose that this interaction is specific for the activated form of the bradykinin B2 receptor. Additionally, we compared and discussed our putative model in the context of the structural model of the partially activated rhodopsin (Rh*) and with the known biochemical and structural data.     

Time-variant reliability profiles for steel girder bridges

Evaluation of existing steel bridges becomes more important due to natural aging, increasing load spectra, deterioration caused by corrosion, and other problems. In the result, bridge structures exposed to aggressive environmental conditions are subjected to time-variant changes of resistance. Therefore, there is a need for evaluation procedures for an accurate prediction of the load carrying capacity and reliability of bridge structures, in order to make rational decisions about repair, rehabilitation, and expected life-cycle costs. The objective of this paper is to develop time-variant reliability models for steel girder bridges. Traditional methods based on deterministic analysis do not reveal the actual load carrying capacity of the structure. The proposed approach is based on reliability analysis of components and structural systems. The study involves the selection of representative structures, formulation of limit state functions, development of load models, development of resistance models for corroded steel girders, development of the reliability analysis method, reliability analysis of selected bridges, and development of the time-dependant reliability profiles including deterioration due to corrosion. The results of the study can be used for a better prediction of the service life of deteriorating steel girder bridges, and development of optimal reliability-based maintenance strategies.