Orthonormal Basis Functions for Continuous-Time Systems and Lp Convergence

In this paper, model sets for linear-time-invariant continuous-time systems that are spanned by fixed pole orthonormal bases are investigated. These bases generalize the well-known Laguerre and two-parameter Kautz cases. It is shown that the obtained model sets are everywhere dense in the Hardy space H ₁(Π) under the same condition as previously derived by the authors for the denseness in the (Π is the open right half plane) Hardy spaces H _p(Π), 1<p<∞. As a further extension, the paper shows how orthonormal model sets, that are everywhere dense in H _p(Π), 1≤p<∞, and which have a prescribed asymptotic order, may be constructed. Finally, it is established that the Fourier series formed by orthonormal basis functions converge in all spaces H _p(Π) and (D is the open unit disk) H _p(D), 1<p<∞. The results in this paper have application in system identification, model reduction, and control system synthesis. Date received: June 16, 1998. Date revised February 4, 1999.     

A novel indicator system for catalytic spectrophotometric determination and speciation of inorganic selenium species （Se（Ⅳ）, Se（Ⅵ）） at trace levels in natural lake and river water samples

A novel catalytic kinetic method is proposed for the determination of Se(IV), Se(VI), and total inorganic selenium in water based on the catalytic effect of Se(IV) on the reduction of Celestine blue by sodium sulfide at pH 7.0 phosphate buffer. The fixed-time method was adopted for the determination and speciation of inorganic selenium. Under the optimum conditions, the two calibration graphs are linear with a good correlation coefficient in the range 2–20 and 20–200 μg·L⁻¹ of Se(IV) for the fixed-time method at 30°C. The experimental and theoretical detection limits of the developed kinetic method were found to be 0.21 and 2.50 μg·L⁻¹ for the fixed-time method (3 min). All of the variables that affect the sensitivity at 645 nm were investigated, and the optimum conditions were established. The interference effect of various cations and anions on the Se(IV) determination was also studied. The selectivity of the selenium determination was greatly improved with the use of the strongly cation exchange resin such as Amberlite IR120 plus as long as chelating agents of thiourea and thiosulphate. The proposed kinetic method was validated statistically and through recovery studies in natural water samples. The relative standard deviations (RSDs) for ten replicate measurements of 2, 10, and 20 μg·L⁻¹ of Se(IV) change between 0.35% and 5.58%, while the RSDs for ten replicate measurements of 3, 6, and 12 μg·L⁻¹ of Se(VI) change between 0.49% and 1.61%. Analyses of a certified standard reference material (NIST SRM 1643e) for selenium using the fixed-time method showed that the proposed kinetic method has good accuracy. The Se(IV), Se(VI), and total inorganic selenium in lake and river water samples have been successfully determined by this method after selective reduction of Se(VI) to Se(IV).     

IDENTIFICATION OF CONTINUOUS‐TIME POWER SPECTRA BY GENERALIZED FOURIER SERIES

In this paper, we present a generalized Fourier series based algorithm for the identification of continuous‐time, linear‐time invariant systems from power spectrum measurements. The algorithm is strongly consistent and it is used in the design of a linear shaping filter for a single‐track road power spectrum.     

Optoelectronic properties n:CdS:In/p-Si heterojunction photodetector

Optoelectronic properties of CdS:In/Si anisotype heterojunction photodetector fabricated by depositing of polycrystalline CdS and indium doped CdS films used thermal resistive technique on clean monocrystalline p-type silicon substrates are presented. The effect of In diffusion temperature(T _d)in CdS layer on the optoelectronic characteristics of these devices has been studied. Two peaks situated at 650 and 800 nm with values of 0.32 and 0.43 A/W, respectively, were observed in the responsivity plot. Other optoelectronics properties such as detectivity, photovoltaic, and response time are also presented.     

Analysing communication in complex distributed decision-making

This paper analyses emergency tasks within the theoretical framework of dynamic environment management with distributed decision-making (DDM). Models of task and work organization are used to analyse verbal exchanges in order to infer collective strategies. A cross-analysis method serves to analyse communication from the standpoint of both semantics and structure of the exchanges. The findings of two empirical comparative studies show that invariants vs differences in the organization and the semantics of exchanges are associated with invariants vs differences in parameters of the situations themselves (initial state and final result of actions). Efficient strategies were linked with well-structured flow of communication and roles distribution.     

Primary retroperitoneal liposarcoma: a case report and review of the literature

We report a case of a 43 years old woman with a retroperitoneal liposarcoma located in the left iliac fossa. The condition was discovered because of the association of left flank pain, abdominal distention and persistent urinary infection with symptoms of vesical irritation. The diagnosis was suggested by intravenous pyelography (IVP), abdominal and pelvic ultrasonography (USG) and computed tomography (CT). Treatment was exclusively surgical. During a six-month follow-up, no recurrence was observed.     

Adsorption equilibria between dye and surfactant in single and binary systems onto geological materials

Adsorption characteristics of cationic dyes and surfactants onto clay and sandstone from a single component system were studied using toluidine blue (TB) and cetyl trimethylammonium bromide (CTAB). Equilibrium data of TB and CTAB in the single solute systems fit well to the Langmuir and the Freundlich adsorption isotherms. Competitive adsorption was observed between dye and surfactant cations. The effect of sodium chloride on dye and surfactant adsorption was studied in TB–NaCl and CTAB–NaCl binary systems. Equilibrium adsorption for binary systems was analyzed by using the extended Langmuir and the extended Freundlich models. Adsorption results for the TB–CTAB system onto both adsorbents were also well described by the Sheindorf–Rebuhn–Sheintuch (SRS) model for multi-component systems. Free energy changes for adsorption systems were calculated using thermodynamic equilibrium constants evaluated from selectivity coefficients of the binary systems. The site distribution functions estimated using Freundlich model parameters gave valuable information about the ratio of the adsorption sites on adsorbent surface having different affinity for competing cations.     

Similarity measures of bipolar neutrosophic sets and their application to multiple criteria decision making

In this paper, we introduced some similarity measures for bipolar neutrosophic sets such as; Dice similarity measure, weighted Dice similarity measure, Hybrid vector similarity measure and weighted Hybrid vector similarity measure. Also we examine the propositions of the similarity measures. Furthermore, a multi-criteria decision-making method for bipolar neutrosophic set is developed based on these given similarity measures. Then, a practical example is shown to verify the feasibility of the new method. Finally, we compare the proposed method with the existing methods in order to demonstrate the practicality and effectiveness of the developed method in this paper.

     

Continuous‐time stable and unstable system modelling with orthonormal basis functions

In this paper, model sets for linear time‐invariant continuous‐time systems which are spanned by fixed‐pole orthonormal bases are investigated. The obtained model sets are shown to be complete in the Lebesque spaces L_p (1<p<∞) and in C, the space of complex‐valued functions that are continuous on the extended imaginary axis. The L_p norm error bounds for estimating systems in L_p by the partial sums of the Fourier series formed by the orthonormal functions are computed for the case 1<p<∞. Some inequalities on the 𝓁_p means of the Fourier coefficients are also derived. These results have application in estimation and model reduction of stable and unstable continuous‐time linear time‐invariant systems. A numerical example illustrates the use of the basis functions for the approximation of unstable infinite‐dimensional dynamics. Copyright © 2000 John Wiley & Sons, Ltd.