Deployment issues for the IP multicast service and architecture

IP multicast offers the scalable point-to-multipoint delivery necessary for using group communication applications on the Internet. However, the IP multicast service has seen slow commercial deployment by ISPs and carriers. The original service model was designed without a clear understanding of commercial requirements or a robust implementation strategy. The very limited number of applications and the complexity of the architectural design-which we believe is a consequence of the open service model-have deterred widespread deployment as well. We examine the issues that have limited the commercial deployment of IP multicast from the viewpoint of carriers. We analyze where the model fails and what it does not offer, and we discuss requirements for successful deployment of multicast services     

Niosomes as a potential drug delivery system for increasing the efficacy and safety of nystatin

Nonionic surfactant (NIS) vesicles (niosomes) formed from self-assembly of hydrated synthetic NIS monomers are capable of entrapping a variety of drugs and have been evaluated as an alternative to liposomes. Nystatin (NYS) is a polyene antifungal drug that has been used in the treatment of cutaneous, vaginal and oral fungal infections since the 1950s. The aim of this work is to encapsulate NYS in niosomes to obtain a safe and effective formula administered parenterally for neutropenic patients. NYS niosomes were prepared by the thin-film hydration method using Span 60 or Span 40 and cholesterol (CHOL). Stearylamine and dicetyl phosphate were added as the positive and negative charge-inducing agents (CIA), respectively. Two molar ratios were used, namely NIS/CHOL/CIA (1:1:0.1 and 2:1:0.25). Neutral and positively charged niosomes gave the highest encapsulation efficiencies. NYS niosomes were characterized using transmission electron microscopy, differential scanning calorimetry and dynamic light scattering. The release of neutral and negatively charged NYS niosomes was estimated, and it showed a slow sustained release profile. A 25-kGy γ-irradiation dose was sufficient to sterilize the investigated vesicles. NYS niosomes exerted less nephrotoxicity and hepatotoxicity in vivo, showed higher level of drug in vital organs and revealed pronounced efficacy in elimination of the fungal burden in experimental animals infected with Candida albicans compared with those treated with free NYS. Niosomal encapsulation thus provided means for parenteral administration of NYS, reducing its toxicity and making it a more active antifungal agent.     

A decision support system for the selection of curtain wall systems at the design development stage

In high rise building construction projects, curtain wall is one of the most widely used exterior finishing components and has a major influence on the overall building operational costs and efficiency in terms of CO₂ emissions. The selection of curtain wall systems involves numerous technical, environmental and economic factors, and impacts on all project stages from concept design, through manufacture to installation and operation. The current way this important decision is being made in the business process, and its simplification, are two important issues that are still unexplored in the literature. After investigating the drawbacks of the current business process using a retrospective case study and an industrial survey, a decision support system (DSS), which consists of a process framework and an integrated relational database as a central repository for the main curtain wall systems and their engineering parameters, is proposed as a potential solution. The DSS developed not only enables the resolution of the main issue of the selection of curtain wall systems at the early design development stage but it also helps specifiers identify multiple technical and commercial options that could be presented to clients in real time.     

Doppler Effect in the Acoustic Ultra Low Frequency Band for Wireless Underwater Networks

It is well known that communication is affected by the change in frequency of a signal for an observer that is moving relative to the source. As a result of the motion of either the source or the observer, successive waves are emitted from a position that may get closer or further to the observer. This phenomenon, known as Doppler effect, also affects underwater acoustic waves used for communications between Autonomous Underwater Vehicles (AUVs), Underwater Sensors (USs) and remote operators. There have been few studies on the impact of Doppler shift in underwater communications. Assuming underwater communications using acoustic waves, in this paper we study the Doppler effect in relation to the half-power bandwidth and distance in the Ultra Low Frequency (ULF) band (i.e., from 0.3 to 3 kHz). We investigate two specific issues. Firstly, the maximum shift that can be expected on underwater links in the ULF band. Secondly, the maximum frequency drift, and associated patterns, that can happen during the reception of data frames. Numeric simulations are conducted. The analysis is based on scenarios that show the existence of significant Doppler effect. More specifically, we show that Doppler effect, under narrow half-power bandwidth, is significant with respect to the half-power bandwidth in the ULF band, for long distance communications. Furthermore, we show that Doppler effect patterns are not necessarily linear.     

Demodulation with a Multichannel Estimation Method Using a Reduced Rank Constraint

This paper deals with the Maximum Likelihood Estimation of the multichannel impulse response in a mobile communication system whose base stations are equipped with antennas arrays. The following problem is solved: using the training sequence, find the maximum likelihood multichannel impulse response from one mobile to the base station under a reduced rank constraint in the presence of gaussian noise and jammers with unknown covariance matrix. This method finds applications in demodulation (the reduced rank channel estimate can be used in a Viterbi Algorithm), and experimental results using real signals demonstrate its high performance compared with the standard Minimum Mean Square Error (MMSE) multichannel estimate.     

Integrating a simplified P-N radiation model with EdmFoam1.5: Model assessment and validation

This work compliments our recently published work of implementing the eddy dissipation turbulent combustion model in OpenFOAM [1]. The major update proposed herein is linking the EdmFoam1.5 solver with radiation modeling libraries in OpenFOAM. The new solver was validated against experimental data for jet and swirling Sydney flame (SM1). Each case was modeled with/without radiation modeling. The results have a fair agreement in general. In jet flame cases, the radiation modeling has a good impact on refining the predicted results. However it has not the same great effect on the swirling flame case. A review of the EDM applications in different reacting flow problems is also presented and discussed.     

Novel Strategy for Hazardous Cement Bypass Dust Removal: Structural,Optical and Nuclear Radiation Shielding Properties of CBD-Bismuth Borate Glass

Journal of Inorganic and Organometallic Polymers and Materials - Herein, this study introduced a novel strategy for hazardous cement bypass dust (CBD) removal via incorporated it into glassy system...     

Structural,Textural and Photocatalytic Properties of Germanium-Doped Zirconium Dioxide

Inorganic Materials - This investigation deals with the structural and textural properties of the monoclinic zirconium oxide (m-ZrO2) doped with various amounts of germanium. The focus was on the...     

Stability of vector optimization problems with fuzzy weights in the objective functions and fuzzy matrix parameters in the constraints

The aim of this paper is to investigate the stability of multiobjective nonlinear programming problems with fuzzy weights in the objective functions and fuzzy matrix parameters in the constraints and represent, in addition, the related dual problems for which the set of feasible parameters and the solvability set are studied. These fuzzy weights and fuzzy matrix parameters are characterized by fuzzy numbers. The existing results concerning the basic notions parametric space in convex programs are redefined and analyzed qualitatively under the concept of α-Pareto optimality. An illustrative example is given to clarify the obtained results.     

Prediction and elimination of hot spots at the crossing regions ofHV cables

A thermal analysis of temperature distributions along the crossing regions of high-voltage cables is presented. It is claimed that the analytical results obtained are in good agreement with the corresponding measured values. The methods of hot-spot elimination by using special backfill or by heat pipes are introduced analytically