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Author

Paul Schiopu

Other affiliations: University of Bucharest
Bio: Paul Schiopu is an academic researcher from Politehnica University of Bucharest. The author has contributed to research in topics: Photonics & Signal. The author has an hindex of 6, co-authored 129 publications receiving 195 citations. Previous affiliations of Paul Schiopu include University of Bucharest.


Papers
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Proceedings ArticleDOI
19 Dec 2013
TL;DR: A new control method for the robot extension control, using the Extenics concepts and Extension Theory techniques, which obtains remarkable results, while having the advantage of increased simplicity in design and setting of parameters.
Abstract: The paper presents a new control method for the robot extension control, using the Extenics concepts and Extension Theory techniques. The controller uses the Dependent Function to measure the degree of compatibility of the process variable and then takes the appropriate action to force the system into convergence around a desired set point. The output of the Dependent Function classifies the process variable value into one of four categories, concurrent with the nested intervals used in Extenics, which are then equated to fuzzy inputs sets of a linguistic variable for a simple fuzzy controller. This acts as a fuzzy smoothing of the controller output. The rationality and validity of the proposed model are demonstrated through simulation in the Matlab/Simulink environment. The results show that the proposed new controller architecture obtains remarkable results, while having the advantage of increased simplicity in design and setting of parameters. Throughout the paper, opportunities for further improvement and research are highlighted and discussed.

16 citations

Proceedings ArticleDOI
04 Oct 2004
TL;DR: The Runge-Kutta method with fourth-order accuracy is the method used to calculate the input pump power and gain for EDFA and the analytical method to determine the EDFA gain as a function ofinput pump power is presented.
Abstract: In this paper, we analyze gain versus pump power for EDFA. The Runge-Kutta method with fourth-order accuracy is the method used to calculate the input pump power and gain for EDFA. In addition, we compare the theoretical results with experimental characterization for gain versus pump power. Also, we present the analytical method to determine the EDFA gain as a function of input pump power.

13 citations

Proceedings ArticleDOI
05 Jan 2009
TL;DR: The white light interferometers allow generally surface profiling with high accuracy with no phase ambiguity errors, making them more suitable for profiling stepped or discontinuous surfaces as mentioned in this paper, and they can measure: surface profile, roughness, step height, microstructure, and other surface parameters.
Abstract: Precise three-dimensional (3D) information is demanded by many new industries such as: semiconductor, photonics, MEMS, communications, microprocessing etc. [1, 2]. The problem is to select the proper measurement methods for material characteristics in the measurement field, from the point of view of the measurement accuracy and errors that can appear [1, 4, 3, 5]. There are several optical 3D measurements approaches, e.g.: triangulation, grating projection with phase shift, moire with phase shift, confocal and (white light) interferometry (WLI) [2, 3]. They can measures: surface profile, roughness, step height, microstructure, and other surface parameters. The white light interferometers allows generally surface profiling with high accuracy with no phase ambiguity errors, making them more suitable for profiling stepped or discontinuous surfaces. WLI technique to determine the thickness of thin coating on reflective materials is very effective. One of the first techniques to utilize the short coherence of the white light source was the scanning interference microscope. There are on the market a variety of scanning white light interferometers. Measurement calibration is done using the short coherence feature of white light. Some of the presented applications in nanometrology are thin films thickness measurements of: carbons films on glass, metallic films on Silicon, ablated small holes diameter, and profiles of micro / nanostructure.

12 citations

Proceedings ArticleDOI
01 Oct 2012
TL;DR: In this article, the preparation of a transparent heterojunction on a glass substrate consisting of p type NiO and n type ITO transparent oxidic semiconductors was presented.
Abstract: The paper presents the preparation of a transparent heterojunction on glass substrate consisting of p type NiO and n type ITO transparent oxidic semiconductors. NiO layer as a p type semiconductor and transparent layer was obtained by thermal oxidation at 430 oC of 50 nm metallic Ni films deposited by DC sputtering. Spectrophotometrical measurements used to investigate optical properties revealed a transmittance higher than 70% for NiO and 90% for ITO in the spectral range of 300–900 nm. The obtained p-NiO/n-ITO heterojunction exposed to ultraviolet radiation (λ ∼ 240 nm) shows a good sensibility due to wide band gap of the layers.

11 citations

Journal ArticleDOI
TL;DR: The paper proposes an innovative type of fuzzy logic controller for robot actuators, building upon the current state of the art fuzzy architectures and various observations from work with Fuzzy Logic and Extenics Theory.
Abstract: The paper proposes an innovative type of fuzzy logic controller for robot actuators, building upon the current state of the art fuzzy architectures and various observations from work with Fuzzy Logic and Extenics Theory. This leads to a modified fuzzy controller, with a significantly simpler rule base, which shows comparable results. The effect is achieved by taking advantage of the rule base makeup of a regular linear fuzzy controller. Some slight modification is needed to the controller architecture, which is explained in detail. The rationality and validity of the proposed model are demonstrated through simulation in the Matlab/Simulink environment. The results show that the proposed new controller architecture obtains remarkable results, while having the advantage of increased simplicity in design and setting of parameters. Throughout the paper, opportunities for further improvement and research are highlighted and discussed.

10 citations


Cited by
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01 Jan 2006
TL;DR: Digital holography is a technique that permits digital capture of holograms and subsequent processing on a digital computer as mentioned in this paper, and various applications of this technique cover three-dimensional (3-D) imaging as well as several problems.
Abstract: Digital holography is a technique that permits digital capture of holograms and subsequent processing on a digital computer. This paper reviews various applications of this technique. The presented applications cover three-dimensional (3-D) imaging as well as several associated problems. For the case of 3-D imaging, optical and digital methods to reconstruct and visualize the recorded objects are described. In addition, techniques to compress and encrypt 3-D information in the form of digital holograms are presented. Lastly, 3-D pattern recognition applications of digital holography are discussed. The described techniques constitute a comprehensive approach to 3-D imaging and processing.

179 citations

Journal ArticleDOI
TL;DR: In this article, an n−n+ type-II homojunction of Zn:BiVO4/Mo:Bi VO4, which improves the bulk transport and surface charge transfer processes of the well-studied BiVO4 photoanode, is reported.
Abstract: Photoelectrochemical (PEC) water splitting has been extensively studied as a method to convert sunlight and water to hydrogen. Among the many obstacles facing PEC water splitting, a critical challenge is the lack of efficient photoanodes for the water oxidation reaction. Here, we report an n–n+ type-II homojunction of Zn:BiVO4/Mo:BiVO4, which improves the bulk transport and surface charge transfer processes of the well-studied BiVO4 photoanode. In this homojunction, the Zn and Mo dopants move the BiVO4 valence band maximum and conduction band minimum, respectively, closer to the Fermi level, establishing an n–n+ type-II homojunction. The staggered band alignment between Zn:BiVO4 and Mo:BiVO4 facilitates electron–hole separation between the two layers. The Mo dopant increases the donor concentration, leading to higher electrical conductivity. The Zn dopant increases the number of oxygen chemisorption sites, improving the interfacial charge transfer process. With additional deposition of the oxygen evolution electrocatalyst Ni:FeOOH, the homojunction achieves charge transport and transfer efficiencies of 65% and 89%, respectively. The final Ni:FeOOH/Zn:BiVO4/Mo:BiVO4 photoanode achieves a photocurrent density of 2.7 mA cm−2 and a faradaic efficiency for oxygen evolution of ∼92% at 1.23 V vs. RHE in the electrolyte of potassium buffer solution (pH ∼ 7).

73 citations