An efficient method for computing cell loss probability for heterogeneous bursty traffic in ATM networks

In this paper, we present an approximation for the probability of cell loss of heterogeneous bursty traffic in broadband integrated packet networks based on the asynchronous transfer mode. The sources considered here alternate between active and silent periods and are characterized by their peak and average transmission rates. The cell loss probability is obtained by considering only the number of active sources at a given time and computing the amount of traffic that exceeds the link capacity. Since the amount of buffered excess traffic is not considered in this computation, this approximation is actually an upper bound of the cell loss probability. The numerical efficiency of this bound enables it to be used as a measure based on which robust and simple resource allocation strategies can be developed for bursty sources. Comparison of this bound with the simulation results has shown that the bound is close to the actual loss probabilities especially for large burst lengths and high utilizations.     

Improved Dissolution of Indomethacin in Coprecipitates with Phospholipids-I

Indomethacin powders were blended with phospholipids to prepare physical mixtures or made into solid dispersions by the solvent method and their comparative dissolution profiles were studied. Indomethacin exhibited significantly improved dissolution rates in phospholipid coprecipitates compared to either the physical mixtures or the pure indomethacin. The coprecipitates of lecithin-indomethacin 1:16 weight ratio had a 6.5 fold greater initial dissolution rate, and the total amount dissolved after 60 minutes was 140% greater compared to indomethacin alone. Increasing the lecithin content to 1:4 resulted in only a modest additional increase in the initial dissolution rate (40%) and the limiting concentration (14%)     

Using the TPS method for determining the thermal properties of concrete and wood at elevated temperature

The transient plane source (TPS) method is shown to be very promising for determining thermal properties of materials at room temperature as well as temperatures up to 700°C. To investigate the applicability of the method it has been used in the study for determining thermal properties of wood (spruce) and concrete. Conductivity (λ) and diffusivity (α) were determined simultaneously. The thermal properties thus obtained have been compared with some values found in literature. The paper also presents results where calculations using properties obtained with the TPS method are compared with fire test measurements. The results are very encouraging. Copyright © 2005 John Wiley & Sons, Ltd.     

Design and in Vitro Evaluation of a Controlled Release Drug Delivery System of Sulfasomidine

A controlled release oral drug delivery system of Sulfasomidine was developed by spray congealing micropelleting technique using gelatin as the embedding matrix. The pellets were hardened by treating with Formalin-Isopropanol mixture. The in vitro release rate studies of Sulfasomidine from the micropelleted dosage form, revealed that the drug release can be prolonged upto eight hours and not more than 39% of the embedded drug released in the first hour of the in vitro dissolution study. The in vitro release patterns correlated with the reported in vivo studies. The method of formulation was optimized.     

Adaptive decision support systems

The effectiveness of decision support systems (DSS) is enhanced through dynamic adaptation of support to the needs of the decision maker, to the problem, and to the decision context. We define this enhanced DSS as adaptive decision support systems (ADSS) and propose its architecture. In an ADSS, the decision maker controls the decision process. However, the system monitors the process to match support to the needs. The proposed architecture evolves from the traditional DSS models and includes an additional intelligent‘Adaptation’ component. The ‘Adaptation’ component workd with the data, model, and interface components to provide adaptive support. The architecture also integrates enhancements proposed in the past research. In this paper, we have illustrated the proposed architecture with two examples, a prototype system, and results from a preliminary empirical investigations     

Design of a dual‐polarized omnidirectional antenna for broadband applications

A broadband dual‐polarized omnidirectional antenna is presented. The proposed antenna consists of two parts, an asymmetric biconical antenna and a cylindrical multilayer polarizer. To have an almost perfect omnidirectional radiation pattern in the horizontal plane and the main radiating beam position at around , in the elevation plane, the asymmetric biconical antenna is used. Moreover, to provide dual polarization performance over the 2–18 GHz operational bandwidth, a multilayer polarizer is designed and optimized. Numerous simulations via Ansoft HFSS and CST microwave Studio CAD tools have been made to optimize the radiation pattern, gain, polarization, and the reflection coefficient of the antenna. Simulation results show that the radiation characteristics of the proposed antenna are extremely sensitive to the configuration and dimensional parameters of the multilayer polarizer. The designed antenna was fabricated with high mechanical accuracy and measured. Satisfactory agreement of computer simulations and experimental results was obtained. The main feature that distinguishes this antenna from the previous designs is the ability to provide the omnidirectional radiation pattern with small ripples, dual polarizations performance, and the wide bandwidth simultaneously. Based on these characteristics, the proposed antenna can be useful for broadband communication applications. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:591–600, 2015.     

Recursive estimation of two-dimensional processes with application to image processing

A low order quarter-plane-causal recursive model is presented to represent the class of 2-D stationary Gaussian processes with power spectra matrices factorable into a quarter-plane-causal and anti-causal parts. This model is used to develop a technique for obtaining optimal 2-D recursive estimators. The approach taken here is similar to Attasi's [8], with no commutability condition imposed on the model. Circumventing this condition allows the modeling of the 2-D processes to be achieved with fewer parameters, and enables one to find the solutions to the problems of blur and color noise which are inherent in most image degraded images. Some simulated examples illustrate these points.This research was supported in part by the U.S. Army Research Grant DAAG29-79-C-0054 and the National Science Foundation Grant ECS-8011911.     

Experimental studies on the development of a cast film

The cast film process is of significant industrial interest. This work presents quantitative experimental results for the characterization of a film casting operation in the region between the die exit and the chill roll. The polymer melt employed is a commercial PET sample that has been characterized in both shear and extension‐dominated flows. Pointwise measurements of both the film temperature and the local velocity are made over the entire region between the die and the chill roll. The velocity increases in the gap, although the strain rate decreases as the polymer moves from the die to the chill roll. For a particular axial position, the velocity decreases significantly near the edges of the film. There are modest (～20 °C) decreases in the temperature between the die and the chill roll, with the greatest variations again occurring near the edges of the film. The experimental results are explained by the coupling between the temperature, velocity fields, and geometry of the experimental apparatus. POLYM. ENG. SCI. 45:443–450, 2005. © 2005 Society of Plastics Engineers.     

Knowledge sharing in dynamic virtual enterprises: A socio-technological perspective

The success of a virtual enterprise depends largely on the effective collaboration of its members in orchestrating their knowledge, skills, core competences and resources, in order to enhance competitive capabilities and respond better to business opportunities. In this paper we address the challenges of knowledge sharing in dynamic virtual enterprises. We take a socio-technological approach by proposing a human-centered knowledge sharing solution and architecture. Specifically, we propose a knowledge resource space model to represent heterogeneous knowledge resources, both explicit and implicit. We then introduce a knowledge sharing community model and adopt an agent based solution to perform the functions of knowledge sharing among members of a dynamic virtual enterprise. Our solution incorporates the concepts of agent society and semantic ontology. Knowledge sharing in dynamic virtual enterprises is performed with three types of ties: knowledge agent to knowledge agent, knowledge agent to knowledge item, and knowledge item to knowledge item. We measure agent-to-agent ties by preference correlation using the contribution degree of one agent to another and the preference similarity degree between two agents. We define a semantic view to show agent-to-item ties and use semantic links in the knowledge resource space model to reflect item-to-item ties. We also elaborate the co-evolution mechanism of collective intelligence across enterprises throughout the lifecycle of a dynamic virtual enterprise. A case study is presented to validate our approach.