Search results for: gain variation.

Authors: Mahmoud Zarrini, R.N. Pralhad

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In this chapter, we have studied Variation of velocity in incompressible fluid over a moving surface. The boundary layer equations are on a fixed or continuously moving flat plate in the same or opposite direction to the free stream with suction and injection. The boundary layer equations are transferred from partial differential equations to ordinary differential equations. Numerical solutions are obtained by using Runge-Kutta and Shooting methods. We have found numerical solution to velocity and skin friction coefficient.

Keywords: Boundary layer, continuously moving surface, shooting method, skin friction coefficient.

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Authors: Liliana Mâţă

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The focus of the study is to understand the factors of curriculum innovation from the perspective of Language teacher education. The overall aim of the study is to investigate Language educators- perceptions of factors of curriculum innovation. In the theoretical framework the main focus is on discussion about different curriculum approaches for language teacher education and limiting and facilitating factors of innovation. In order to achieve the aim of the study, an observational research is employed. The empirical basis of the study consists of questionnaire with sixty-three language teachers from eight Romanian higher education institutions. The findings reveal variation in Language teachers- conceptions of the dominant factors of curricular innovation.

Keywords: curriculum innovation, factors, Language teacher education

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Authors: T. Watanabe

Abstract:

Combustion analysis of suspended sodium droplet is performed by solving numerically the Navier-Stokes equations and the energy conservation equations. The combustion model consists of the pre-ignition and post-ignition models. The reaction rate for the pre-ignition model is based on the chemical kinetics, while that for the post-ignition model is based on the mass transfer rate of oxygen. The calculated droplet temperature is shown to be in good agreement with the existing experimental data. The temperature field in and around the droplet is obtained as well as the droplet shape variation, and the present numerical model is confirmed to be effective for the combustion analysis.

Keywords: Combustion, analysis, sodium, droplet.

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Authors: A. Petz, S. Duckwitz, C. Schmalz, S. Meyer, S. Mütze-Niewöhner, C.M. Schlick

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Although services play a crucial role in economy, service did not gain as much importance as productivity management in manufacturing. This paper presents key findings from literature and practice. Based on an initial definition of complex services, seven productivity concepts are briefly presented and assessed by relevant, complex service specific criteria. Following the findings a complex service productivity model is proposed. The novel model comprises of all specific dimensions of service provision from both, the provider-s as well as costumer-s perspective. A clear assignment of identified value drivers and relationships between them is presented. In order to verify the conceptual service productivity model a case study from a project engineering department of a chemical plant development and construction company is presented.

Keywords: assessment model, complex services, service productivity model, value driver.

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Authors: A.V. Hoseini, A. Bidi, M. H. Pol, M.Jalali azizpour

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In this paper stress and strain for two rotating thin wall cylinder fitted together with initial interference and overlap are computed. Also stress value for variation of initial interference is calculated. At first problem is considered without rotation and next angular velocity increased from 0 to 50000 rev/min and stress in each stage is calculated. The important point is that when stress become very small in magnitude the angular velocity is critical and two cylinders will separate. The critical speed i.e. speed of separation is calculated in each step.

Keywords: Thin walled cylinder, high angular velocity, twofitted thin walled

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Authors: Shaina Nagpal, Amit Gupta

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In this work, all optical Stimulated Brillouin Scattering (SBS) generated single sideband with suppressed carrier is presented to provide better efficiency. The generation of single sideband and enhanced carrier power signal using the SBS technique is further used to strengthen the low shifted sideband and to suppress the upshifted sideband. These generated single sideband signals are able to work at high frequency ranges. Also, generated single sideband is validated over 90 km transmission using single mode fiber with acceptable bit error rate. The results for an equivalent are then compared so that the acceptable technique is chosen and also the required quality for the optimum performance of the system is reported.

Keywords: Stimulated Brillouin scattering, radio over fiber, upper side band, quality factor.

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Authors: Lv Xiaopeng, Bian Qiang, Yue Suge

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A fully on-chip low drop-out (LDO) voltage regulator with 100pF output load capacitor is presented. A novel frequency compensation scheme using current buffer is adopted to realize single dominant pole within the unit gain frequency of the regulation loop, the phase margin (PM) is at least 50 degree under the full range of the load current, and the power supply rejection (PSR) character is improved compared with conventional Miller compensation. Besides, the differentiator provides a high speed path during the load current transient. Implemented in 0.18μm CMOS technology, the LDO voltage regulator provides 100mA load current with a stable 1.8V output voltage consuming 80μA quiescent current.

Keywords: capacitor-less LDO, frequency compensation, transient response, power supply rejection

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Authors: Dhiflaoui Hafedh, Khlifi Kaouthar, Ben Cheikh Larbi Ahmed

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The present study deals with the characterization of CrSiN coatings obtained by PVD magnetron sputtering systems. CrSiN films were deposited with different Si contents, in order to check the effect of at.% variation on the different properties of the Cr–N system. Coatings were characterized by scanning electron microscopy (SEM) for thickness measurements, X-ray diffraction. Surface morphology and the roughness characteristics were explored using AFM, Mechanicals properties, elastic and plastic deformation resistance of thin films were investigated using nanoindentation test. We observed that the Si addition improved the hardness and the Young’s modulus of the Cr–N system. Indeed, the hardness value is 18,56 GPa for CrSiN coatings. Besides, the Young’s modulus value is 224,22 GPa for CrSiN coatings for Si content of 1.2 at.%.

Keywords: Thin film, mechanicals properties, PVD.

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Authors: Smrity Dwivedi

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The present paper has revealed the effect of double substrates over a bandwidth performance for planar antennas. The used material has its own importance to get minimum return loss and improved directivity. The author has taken double substrates to enhance the efficiency in terms of gain of antenna. Metamaterial based antenna has its own specific structure which increased the performance of antenna. Improved return loss is -20 dB, and the voltage standing wave ratio (VSWR) is 1.2, which is better than single substrate having return loss of -15 dB and VSWR of 1.4. Complete results are obtained using commercial software CST microwave studio.

Keywords: Metamaterials, return loss, standing wave ratio, directivity, CST microwave studio.

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Authors: M. Glomski, M. Lopes

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Seemingly simple probabilities in the m-player game bingo have never been calculated. These probabilities include expected game length and the expected number of winners on a given turn. The difficulty in probabilistic analysis lies in the subtle interdependence among the m-many bingo game cards in play. In this paper, the game i got it!, a bingo variant, is considered. This variation provides enough weakening of the inter-player dependence to allow probabilistic analysis not possible for traditional bingo. The probability of winning in exactly k turns is calculated for a one-player game. Given a game of m-many players, the expected game length and tie probability are calculated. With these calculations, the game-s interesting payout scheme is considered.

Keywords: Conditional probability, games of chance, npersongames, probability theory.

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Authors: Supranee Wattanasin

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The purpose of this research was to enhance student’s media literacy. The process was divided into 4 periods: the first phase was to hold the meeting for 100 representatives from various institutions in Thailand; the second phase allowed them to design activities to be used in their institutions; the third implemented activities to reach other target groups; and the last phase was to summarize results. It was found that the participants had clear understanding on media literacy. They knew well about the media. In other words, they knew the difference between creative media and bad ones. Students could use analytical process when searching for information. Thus, the project enabled the students to use analytical thinking skills in designing new activities. Therefore, they could creatively integrate Thai folk song with short movies and cartoons. To increase students’ media literacy, there should be chances for them to gain first-hand experience.

Keywords: Management, development, media literacy, Thai students.

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Authors: Asmaa Amehraye, Dominique Pastor, Ahmed Tamtaoui, Driss Aboutajdine

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A new analysis of perceptual speech enhancement is presented. It focuses on the fact that if only noise above the masking threshold is filtered, then noise below the masking threshold, but above the absolute threshold of hearing, can become audible after the masker filtering. This particular drawback of some perceptual filters, hereafter called the maskee-to-audible-noise (MAN) phenomenon, favours the emergence of isolated tonals that increase musical noise. Two filtering techniques that avoid or correct the MAN phenomenon are proposed to effectively suppress background noise without introducing much distortion. Experimental results, including objective and subjective measurements, show that these techniques improve the enhanced speech quality and the gain they bring emphasizes the importance of the MAN phenomenon.

Keywords: Perceptual speech filtering, maskee to audible noise, distorsion, musical noise.

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Authors: Zeinab Jokar, Mohammad Reza Moslemi

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In this work, we study the behavior of introducing atomic size vacancy in a graphene nanoribbon superlattice. Our investigations are based on the density functional theory (DFT) with the Local Density Approximation in Atomistix Toolkit (ATK). We show that, in addition to its shape, the position of vacancy has a major impact on the electrical properties of a graphene nanoribbon superlattice. We show that the band gap of an armchair graphene nanoribbon may be tuned by introducing an appropriate periodic pattern of vacancies. The band gap changes in a zig-zag manner similar to the variation of band gap of a graphene nanoribbon by changing its width.

Keywords: Antidot, Atomistix ToolKit, Superlattice, Vacancy.

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Authors: Daniela F. Maluf, Fernanda Roters, Luma C. F. Silva

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The goal of this work is to report the main dermatological alterations occurring during pregnancy and actual cosmetic protocols available and recommended for safe use. Throughout pregnancy, woman's body undergoes many transformations such as hormonal changes and weight gain. These alterations can result in undesirable skin aspects that end up affecting the future mother's life. The main complaints of pregnant women involve melasma advent, varicose veins, edema, and natural skin aging. Even if most of the time is recommended to wait for the birth to use cosmetics, there are some alternatives to prevent and to treat these alterations during pregnancy. For all these cases, there is a need to update information about safety and efficacy of new actives and technologies in cosmetic products. The purpose of this study was to conduct a literature review about the main skin alterations during pregnancy and actual recommended treatments, according to the current legislation.

Keywords: Pregnancy, cosmetic, treatment, physiological changes.

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Authors: Suhas K, Sripadaraja K

Abstract:

This paper details few mechanical modeling and design issues of RF MEMS switches. We concentrate on an electrostatically actuated broad side series switch; surface micromachined with a crab leg membrane. The same results are extended to any complex structure. With available experimental data and fabrication results, we present the variation in dynamic performance and compliance of the switch with reference to few design issues, which we find are critical in deciding the dynamic behavior of the switch, without compromise on the RF characteristics. The optimization of pull in voltage, transient time and resonant frequency with regard to these critical design parameters are also presented.

Keywords: Microelectromechanical Systems (MEMS), RadioFrequency MEMS, Modeling, Actuators

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Authors: N. Ojaroudi Parchin, H. Jahanbakhsh Basherlou, Y. Al-Yasir, A. M. Abdulkhaleq, R. A. Abd-Alhameed, P. S. Excell

Abstract:

A compact design of multi-sector patch antenna array for 60 GHz applications is presented and discussed in details. The proposed design combines five 1x8 linear patch antenna arrays, referred to as sectors, in a multi-sector configuration. The coaxial-fed radiation elements of the multi-sector array are designed on 0.2 mm Rogers RT5880 dielectrics. The array operates in the frequency range of 58-62 GHz and provides switchable directional/omnidirectional radiation beams with high gain and high directivity characteristics. The designed multi-sector array exhibits good performances and could be used in the fifth generation (5G) cellular networks.

Keywords: MM-wave communications, multi-sector array, patch antenna, small cell networks.

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Authors: Kexin Jia, Youxin Lu

Abstract:

To make the modulation classification system more suitable for signals in a wide range of signal to noise rate (SNR), a novel method of designing combined classifier based on fuzzy neural network (FNN) is presented in this paper. The method employs fuzzy neural network classifiers and interclass distance (ICD) to improve recognition reliability. Experimental results show that the proposed combined classifier has high recognition rate with large variation range of SNR (success rates are over 99.9% when SNR is not lower than 5dB).

Keywords: Modulation classification, combined classifier, fuzzy neural network, interclass distance.

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Authors: Muthatakul Metasit, Setthasakko Watchaneeporn

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At present, increased concerns about global environmental problems have magnified the importance of sustainability management. To move towards sustainability, companies need to look at everything from a holistic perspective in order to understand the interconnections between economic growth and environmental and social sustainability. This paper aims to gain an understanding of key determinants that drive sustainability management and barriers that hinder its development. It employs semi-structured interviews with key informants, site observation and documentation. The informants are production, marketing and environmental managers of the leading wine producer, which aims to become an Asia-s leader in wine & wine based products. It is found that corporate image and top management leadership are the primary factors influencing the adoption of sustainability management. Lack of environmental knowledge and inefficient communication are identified as barriers.

Keywords: Environmental, knowledge; Sustainability management; Top management leadership; Wine industry

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Authors: Maja Martinovic, Valentina Zarkovic, Hrvoje Maljak

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Europe is one of the most popular tourist destinations in the world, in which tourism occupies a significant place among the most relevant economic activities, and this applies to the Republic of Croatia as well. Based on this study, the authors intended to encourage and support the creation of an effective tourism policy in Croatia that would be based on the profiling of certain target groups. Another objective was to compare the results obtained from the customer analysis with the market analysis of the tourism industry in Croatia. The objective is to adapt the current tourist offer according to the identified needs and expectations of a particular tourist group in order to increase the attractiveness of Croatia as a tourist destination and motivate greater attendance of the targeted tourist groups. The current research was oriented towards the Russian market as the target group. Therefore, the authors wanted to encourage a discussion on how to attract more Russian guests. Consequently, the intention of the research was a detailed analysis of Russian tourists, in order to gain a better understanding of their travelling motives and tendencies. Furthermore, attention was paid to the expectations of Russian customers and to compare them with the Croatian tourist offer, and to determine whether there is a possibility for an overlap. The method used to obtain the information required was a survey conducted among Russian citizens about their travelling habits. The research was carried out on the basis of 166 participants of different age, gender, profession and income group. The sampling and distribution of the survey took place between May and July 2016. The results provided from the research indicate that Croatian tourism has certain unrealized potential considering the popularization of Croatia as a tourist destination, and there is a capacity for increasing the revenues within the group of Russian tourists. Such a conclusion is based on the fact that the Croatian tourist offer and the preferences of the Russian guests are compatible, i.e. they overlap in many aspects. The results demonstrate that beautiful nature, cultural and historical heritage as well as the sun and sea, play a leading role in attracting more Russian tourists. It is precisely these elements that form the three pillars of the Croatian tourist offer. On the other hand, the profiling revealed that the most desirable destinations for the Russian guests are Italy and Spain, both of which provide the same main tourist attractions as Croatia. Therefore, the focus of the strategic ideas given in the paper shifted to other tourism segments, such as type of accommodation, sales channels, travel motives, additional offer and seasonality etc., in order to gain advantage in the Russian market, the Mediterranean region and tourism in general. The purpose of the research is to serve as a foundation for analysing the attractiveness of the other tourist destinations in the Russian market, as well as to be a general basis for a more detailed profiling of the various specific target groups of the Russian and other tourist groups.

Keywords: Croatia, Russian market, target groups, tourism, tourist destination.

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Authors: Hadi Adibi-Asl, Alireza Doosthosseini, Amir Taghavipour

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This paper studies the design of an adaptive control strategy to tune an active steering system for better drivability and maneuverability. In the first step, adaptive control strategy is applied to estimate the uncertain parameters on-line (e.g. cornering stiffness), then the estimated parameters are fed into the pole placement controller to generate corrective feedback gain to improve the steering system dynamic’s characteristics. The simulations are evaluated for three types of road conditions (dry, wet, and icy), and the performance of the adaptive pole placement control (APPC) are compared with pole placement control (PPC) and a passive system. The results show that the APPC strategy significantly improves the yaw rate and side slip angle of a bicycle plant model.

Keywords: Adaptive control, active steering, pole placement, vehicle dynamics.

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Authors: Maral Mohamadi Zanjani

Abstract:

In recent decade's tourism industry is one of main reasons of the social and economical development for many countries; so these countries try to gain more portion of it for themselves. The excessive natural and cultural touristy potentialities in Iran made this country to be one of the most attractive sightseeing areas, although; Iran has got the lowest rate of tourists. Khark Island is about 32 km. It is a beautiful coral reef coast; about 98% of oil export has been done through this place. The ecotourism potentialities of Khark and Kharko Islands (about 3.7km far from Khark) are the reason to consider ecotourism and the main activity in these islands which is exporting oil at the same time. This article refers to way of measuring the geographical coordination of the place, and the potentialities, ecotourism attraction of the islands and introduces some ideas in order to expand tourism in the islands.

Keywords: Ecotourism, expansion, tourism, attraction, dominant function, Khark and Kharko Islands

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Authors: Mohammed T. Shukri

Abstract:

The failure of bridges due to excessive local scour during floods poses a challenging problem to hydraulic engineers. The failure of bridges piers is due to many reasons such as localized scour combined with general riverbed degradation. In this paper, we try to estimate the temporal variation of scour depth at nonuniform cylindrical bridge pier, by experimental work conducted in hydraulic laboratories of Gaziantep University Civil Engineering Department on a flume having dimensions of 8.3 m length, 0.8 m width and 0.9 m depth. The experiments will be carried on 20 cm depth of sediment layer having d₅₀=0.4 mm. Three bridge pier shapes having different scaled models will be constructed in a 1.5m of test section in the channel.

Keywords: Scour, local scour, bridge piers, scour depth.

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Authors: R. K. Singh, P. K. Jain

Abstract:

In the present paper, disc loaded interaction structure for potential application in wideband Gyro-TWT amplifier has been analyzed, taking all the space and modal harmonics into consideration, for the eigenwave solutions. The analysis has been restricted to azimuthally symmetric TE0,n mode. Dispersion characteristics have been plotted by varying the structure parameters and have been validated against HFSS simulation results. The variation of eigenvalue with respect to different structure parameters has also been presented. It has been observed that disc periodicity plays very important role for wideband operation of disc-loaded Gyro-TWT.

Keywords: Broadbanding, Disc-loaded interaction structure, Eigenvalue, Gyro-TWT, HFSS.

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Authors: J. Mendoza-López, S. Sánchez-Solano, J. L. Huertas-Díaz

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An array of piezoelectric micro actuators can be used for radiation of an ultrasonic carrier signal modulated in amplitude with an acoustic signal, which yields audio frequency applications as the air acts as a self-demodulating medium. This application is known as the parametric array. We propose a parametric array with array elements based on existing piezoelectric micro ultrasonic transducer (pMUT) design techniques. In order to reach enough acoustic output power at a desired operating frequency, a proper ratio between number of array elements and array size needs to be used, with an array total area of the order of one cm square. The transducers presented are characterized via impedance, admittance, noise figure, transducer gain and frequency responses.

Keywords: Pizeoelectric, Microspeaker, MEMS, pMUT, Parametric Array

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Authors: Nedeljko Cvejic, Tapio Sepp

Abstract:

A study of the obtainable watermark data rate for information hiding algorithms is presented in this paper. As the perceptual entropy for wideband monophonic audio signals is in the range of four to five bits per sample, a significant amount of additional information can be inserted into signal without causing any perceptual distortion. Experimental results showed that transform domain watermark embedding outperforms considerably watermark embedding in time domain and that signal decompositions with a high gain of transform coding, like the wavelet transform, are the most suitable for high data rate information hiding. Keywords?Digital watermarking, information hiding, audio watermarking, watermark data rate.

Keywords: Digital watermarking, information hiding, audio watermarking, watermark data rate.

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Authors: Tian Hai, Yang Shengsheng, Jr., Wang Yi

Abstract:

Based on an analysis of the mechanism of degradation of optical characteristics of the ZnO-pigmented white paint by electron irradiation, a model of single molecular color centers is built. An equation that explains the relationship between the changes of variation of the ZnO-pigmented white paint-s spectrum absorptance and electron fluence is derived. The uncertain parameters in the equation can be calculated using the curve fitting by experimental data. The result indicates that the model can be applied to predict the degradation of optical characteristics of ZnO-pigmented white paint by electron radiation.

Keywords: ZnO-pigmented white pain, effects of electron radiation, optical characteristics degradation, prediction model.

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Authors: Ali Reza Sahab, Amir Gholami Pastaki

Abstract:

In this paper, backstepping method (BM) is proposed for a single-link flexible mechanical manipulator. In each step of this method a positive value is obtained. Selections of the gain factor values are very important because controller will have different behavior for each different set of values. Improper selection of these gains can lead to instability of the system. In order to choose proper values for gains BELBIC method has been used in this work. Finally, to prove the efficiency of this method, the obtained results of proposed model are compared with robust controller one. Results show that the combination of backstepping and BELBIC that is presented here, can stabilized the system with higher speed, shorter settling time and lower overshoot in than robust controller.

Keywords: single-link flexible manipulator, backstepping, BELBIC

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Authors: Zixin Liu, Jianjun Jiao Wanping Bai

Abstract:

In this paper, the issue of pth moment exponential stability of stochastic recurrent neural network with distributed time delays is investigated. By using the method of variation parameters, inequality techniques, and stochastic analysis, some sufficient conditions ensuring pth moment exponential stability are obtained. The method used in this paper does not resort to any Lyapunov function, and the results derived in this paper generalize some earlier criteria reported in the literature. One numerical example is given to illustrate the main results.

Keywords: Stochastic recurrent neural networks, pth moment exponential stability, distributed time delays.

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Authors: Azza M. Anis, M. M. Abutaleb, Hani F. Ragai, M. I. Eladawy

Abstract:

This paper presents the characterization and design of a capacitive pressure sensor with LC-based 0.35 µm CMOS readout circuit. SPICE is employed to evaluate the characteristics of the readout circuit and COMSOL multiphysics structural analysis is used to simulate the behavior of the pressure sensor. The readout circuit converts the capacitance variation of the pressure sensor into the frequency output. Simulation results show that the proposed pressure sensor has output frequency from 2.50 to 2.28 GHz in a pressure range from 0.1 to 2 MPa almost linearly. The sensitivity of the frequency shift with respect to the applied pressure load is 0.11 GHz/MPa.

Keywords: CMOS LC-based oscillator, micro pressure sensor, silicon carbide

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Authors: Dj. Cherifi, Y. Miloud, A. Tahri

Abstract:

The primary objective of this paper is to elimination of the problem of sensitivity to parameter variation of induction motor drive. The proposed sensorless strategy is based on an algorithm permitting a better simultaneous estimation of the rotor speed and the stator resistance including an adaptive mechanism based on the lyaponov theory. To study the reliability and the robustness of the sensorless technique to abnormal operations, some simulation tests have been performed under several cases.

The proposed sensorless vector control scheme showed a good performance behavior in the transient and steady states, with an excellent disturbance rejection of the load torque.

Keywords: Induction Motor Drive, field-oriented control, adaptive speed observer, stator resistance estimation.

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