Approximation of fir digital filters by bilinear transformation

The approximation of the finite-impulse-response (FIR) digital filters using the bilinear transformation of a restricted class of the rational functions is considered. The reference rational functions are constructed for maximally flat selective and quadrature filters. The proposed method can be directly used for both even and odd degree filters, and yields simple explicit expressions for the filter coefficients.     

Experiences with the rectal use of chemotherapeutic agents. 2. Pharmacokinetic examinations with animals

Pediatric oncology nursing would benefit from more research directed toward questions that relate to the care of children with cancer. There are many ideas and proposals that are begun but never carried to fruition. This article will detail how to assess and rework a research proposal to provide the basis for a research project that will add to the scientific knowledge of nursing care of children with cancer.     

A theoretical analysis of flexional bending of Al/Al2O3 S-FGM thick beams

In this paper, an elastic, rectangular, and simply supported, sigmoid functionally graded material (S-FGM) beam of thick thickness subjected to uniformly distributed transverse loading has been investigated. The S-FGM system consists of ceramic (Al₂O₃) and metal (Al) phases varying through the thickness of beam. Major classes of representative theories such as classical laminate beam theory (CLBT), first-order shear deformation theory (FSDT) and high-order theories (HOTs) have been considered and a unified kinematic formulation is then proposed. The Poisson’s ratio of the thick S-FGM beam is assumed to be constant, but their Young’s moduli vary continuously throughout the thickness direction according to the volume fraction of constituents defined by sigmoid function. The numerical illustrations concern bending response of S-FGM rectangular beams. Qualitative and quantitative assessments of displacement and stress fields have been presented and discussed.     

Understanding the impact of loyal user behaviour on Internet access pricing: a game-theoretic framework

In this paper, we investigate the impacts of user behaviour—user loyalty in particular—on pricing strategies of Internet Service Providers (ISPs) for a profitable yet sustainable Internet access marketplace. We carry out an extensive empirical analysis of customer loyalty issues of ISP markets including our own survey in the Hungarian ISP market. Based on the empirical results, we propose a realistic user loyalty model, the price difference dependent loyalty model. Next, we apply the loyalty model in game-theoretical framework where optimal Internet access pricing strategies are expressed. Our game-theoretic framework includes both short-term and long-term interaction cases (single-shot and repeated games, respectively) and is capable of dealing with uncertain as well as dynamic scenarios (Bayesian and Stackelberg games, respectively). Finally, we present the impacts of user loyalty on the prices and profits of ISPs in different scenarios based on simulation results.     

In-situ measurement of magnetic nanoparticle quantity in a microfluidic device

Microsystem Technologies - In this article we demonstrate a method for the accurate in situ determination of the quantity of the entrapped magnetic nanoparticles in the reaction chamber of a...     

Present state and future plans of telecommunications services inHungary

The paper reviews the current state and the development strategies of telecommunications in Hungary. Telephone systems are predominantly analog, with a relatively low main-line penetration ratio (14.5% by the end of 1993) and several years waiting time. Advanced telecommunications services are scarcely established. However, the significance of telecommunications has been recognized, therefore intensive development and modernization plans were formed, the legislative environment has been liberalized, the state-owned network operator has been partly privatized, and the full restructuring of the telecommunication sector is in process. Over the last several years, Hungary focused on the basic network infrastructure and fixed telephone service, but mobile telephony was also urgently required for the rapid satisfaction of business needs. The need to join Europe accelerates the pace of digitalization and the introduction of new telecommunication services, as well as the establishment of international cooperation to harmonize the expansion of international links. The paper summarizes the general features and development goals for this decade     

Reform and development of Hungarian telecommunications

This article presents the reform of the Hungarian telecommunications sector, including changes in legislation, regulation, ownership, and sector structure. The present structures of the market and regulatory environments are also shown. The phases of the telecommunications development strategy are outlined, and the last ten years' progress is demonstrated and compared to the development of other European countries. Technological convergence and EU integration, the major challenges for Hungarian telecommunications, are also sketched     

Experiences with the rectal use of trimethoprim

The possibility of rectal use of trimethoprim was studied. The in-vitro liberation of the drug from 24 different suppository bases was examined and the results used to select bases for in-vivo examination. The in-vitro liberation from the suppositories containing 50-200 mg trimethoprim was studied by the method of dynamic diffusion, and the released drug content was measured spectrophotometrically. The in-vivo examinations were performed in anaesthetized rats. The concentration of trimethoprim in blood was determined by bioassay. The absorption of the drug in the form of oral suspension, rectal solution and suppository was also studied. The pharmacokinetic parameters obtained after blood-level curve fitting were compared by use of the MedUSA 1.6 program. The best in-vivo results were achieved with the lipohydrophilic Witepsol W 35 vehicle containing 10% polysorbate 20 and 10% polysorbate 61 (bioavailability = 63.8%) and with Witepsol W 35 containing 10% polysorbate 60 (bioavailability = 63.8%). The results for hydrophilic Macrogol 1540 vehicle containing 5% of Macrogol 400 were only slightly worse (bioavailability = 52.9%). In the case of the lipohydrophilic Witepsol W 35 vehicle with 10% polysorbate 20 and 10% polysorbate 61 content a significant negative exponential relationship was found between the administered doses and their respective bioavailability values; this tendency was also observed during in-vitro examinations. When incorporated in the appropriate vehicle trimethoprim was absorbed well. With three vehicles the extent of absorption exceeded that for oral administration on the same model (bioavailability = 38.8%). Trimethoprim rectal suppositories, which are formulated with the vehicles having the best in-vitro and in-vivo results, are suitable for clinical pharmacological investigation.