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In this article, a novel DC-DC converter is proposed, which is derived from the parallel combination of a conventional boost converter and a Quasi-Z-Source converter. This converter benefits from the features of both mentioned converters. Compared to similar structures, the proposed converter has a suitable gain. This is due to the parallel combination of two voltage-boosting structures, namely boost and Quasi-Z-Source. The simple and linear circuit operation of the converter is another advantage. On the other hand, the control circuit of the converter is also simple and can be designed as PWM. Due to the Quasi-interleaved structure at the input of the proposed converter, the input current is divided between two input paths. This reduces the current stress on active and passive elements. The input filter inductor has a large value. Therefore, the input current of the converter is continuous, and the converter operates in CCM. Additionally, the input current ripple is improved, which is suitable for many applications. The ohmic losses of the elements are low due to the current division between parallel paths. Therefore, its efficiency is improved compared to similar structures. This article presents the design and performance analysis of the proposed converter. To validate the converter's performance, an 80-watt circuit was designed and simulated using PSPICE software. The comparison between the simulation results and the theoretical analysis of the proposed converter substantiates the accuracy of the proposed converter's operation. [ABSTRACT FROM AUTHOR]

The improved three-dimensional imaging system by near-infrared light emission in breast tissue to more accurate diagnosis of tumour is presented in this paper. Based on the repeated experiments in this research, the result is that in this imaging system a more accurate diagnosis of abnormal area depends on the location of the sources and detectors. Therefore, an optimal location model has been proposed to a more suitable placement of sources and detectors. In this article, human samples with the breast cancer have not been examined due to the inaccessibility of three-dimensional imaging system by near-infrared lights. These experiments should have been conducted frequently for obtaining the more accurate reconstructed images, in order to evaluate the optical image reconstruction toolbox of NIRFAST 7.2 that has been coded in MATLAB programming environment and then the obtained results have been compared with the results of similar articles. The obtained results have shown that the proposed placement of sources and detectors has detected the abnormal area with a much lower error rate as well as the proposed placement of sources and detectors has provided a good result in simultaneous diagnosis of the two abnormal areas. [ABSTRACT FROM AUTHOR]

The flow and heat transfer of a novel type of functional phase change nanofluids, nano-encapsulated phase change suspensions, is investigated in the present study using a deep neural networks framework. A deep neural network was used to learn the natural convection flow and heat transfer of the phase change nanofluid in an enclosure. A dataset of flow and heat transfer samples containing 3290 samples of the flow field and temperature distributions was used to train the deep neural network. The design variables were fusion temperature of nanoparticles, Stefan number, and Rayleigh number. The results showed that the proposed combination of a feed-forward neural network and a convolutional neural network as a deep neural network could robustly learn the complex physics of flow and heat transfer of phase change nanofluids. The trained neural network could estimate the flow and heat transfer without iterative and costly numerical computations. The present neural network framework is a promising tool for the design and prediction of complex physical systems. [ABSTRACT FROM AUTHOR]

Learning and memory involve a complex cognitive process to acquire, retain, and retrieve information in the central nervous system. However, the brain mechanism still needs to be well understood. This study aimed to examine the dynamic auditory verbal learning model of the brain mechanism involved in cognitive learning using the scale-free approach by the fractal analysis of electroencephalogram (EEG) data. This illustrates how the complexity of information processing in the brain changes while auditory and verbal learning occurs. Therefore, a standard verbal-auditory cognitive assessment test was used to create a learning paradigm. Eighteen healthy male volunteers (19–23 years old) were recruited and their verbal memories were assessed using the Rey auditory verbal learning test. Fifteen unrelated words were sequentially presented to the subjects and they were asked to recall the presented words as many as possible. The experiment was repeated five times with no stop in between. EEG recording was performed before, during and after each stage. Subsequently, the Hurst exponents of EEG were calculated and their associations with the recalled words and the learning rate were estimated. The approximate entropy was intended to confirm the Hurst exponent variations of signals. The statistical analysis of the data showed that the increase in the number of the recalled words was positively correlated with an increase in the Hurst exponents of EEG signals (more significant at the temporal channels) and a decrease in the approximate entropy of EEG signals during the learning of trials. These results denoted a reduced complexity pattern in EEG signals while rehearsing auditory and verbal memories. [ABSTRACT FROM AUTHOR]

A new method for designing a compact microstrip lowpass filter (LPF) with wide stopband width (SBW) and sharp roll off (ROF) is presented. In the proposed designing procedure, high impedance microstrip lines are bent to achieve an LPF with compact size. Then, to compensate for the effect of bending microstrip lines, the lengths of the lines are mathematically modified. Moreover, adding a suppressing cell composed of a radial stub resonator and a butterfly stub resonator increases the SBW. Also, an elliptic filter structure is used to obtain sharp ROF. In this work, an LPF with 1.12 GHz cutoff frequency, 0.147 μg x 0.133 μg filter size; where μg is the guided wavelength at cutoff frequency, the SBW equal to 13.4 GHz, and the ROF more than 201 dB / GHz, is designed, simulated and fabricated to demonstrate efficiency of the proposed method. Also, the other conventional characteristics for the fabricated LPF such as 0.3 dB insertion loss, 14.4 dB return loss, and suppression factor equal to 2.2, are in the appropriate range of their amounts. [ABSTRACT FROM AUTHOR]

In this paper we want to design linear amplifiers for the Multi Frequency Network (MFN) or Single Frequency Network (SFN) digital terrestrial applications for Digital Video Broadcasting-Terrestrial (DVB-T/T2) transmitters with frequencies of 400 to 900 MHz, so to achieve this aim, we have used Laterally Diffused Metal Oxide Semiconductor (LDMOS) transistor technology has been used. The RF input signal reaches the divider ballun, and then the input of both LDMOS transistors is given and the output of two transistors by the collector balloon reaches the output of the amplifier. We have simulated this design by using the Agilent Design System (ADS) software simulator with a gain more than 24 dB, the (Inter Modulation Distortion (IMD) signal has been attenuated from -29 to -52.5dBc and Power Added Effeciency (PAE) from 48 to 66% with 4-stage matching network consisting of capacitors and microstrips with a drain bias voltage of 28 volts and gate bias voltage of 2.86 volts in the frequency range 400 to 900 MHz. Eventually all of the circuit is designed on a printed circuit board. [ABSTRACT FROM AUTHOR]

This paper presents a modified model to calculate the fractal dimension of digital images. The estimation of fractal dimensions is crucial to fractal analysis and is popularly carried out through methods based on box counting. The problem with these approaches is that, most of them do not remove the potential effects of noise on fractal dimensions properly. Accordingly, this study examines the effects of three different type of noises on fractal dimensions using different images taken from Background image database. The examination shows that the fractal dimensions change significantly, after noise adding, so we put forward a noise-robust and efficient fractal dimension calculation method which is a combination of two methods, the gray-level co-matrix algorithm and improved box counting method. The results of experiments on the Background image dataset confirm the robustness and efficiency of the proposed method. [ABSTRACT FROM AUTHOR]

Many researchers have done a lot on memcapacitor emulator circuits. It is due to the point that memcapacitor as a twoterminal element has not existed yet. These circuits must be developed their use in other applications and scientific fields, consequently many emulators have been designed. The configuration of the proposed memcapacitor structure in this paper is very memorable due to the possibility of fabrication of a completely integrated proposed circuit. In this paper initially, the physical model implementation of memcapacitor has been simulated by Advance Design System (ADS) software, and then a new structure of memcapacitor emulator operating up to 256 Hz with available electronic devices is proposed. Experimental and practical results show the behaviour of memcapacitor as a memory device. [ABSTRACT FROM AUTHOR]

In this paper, a new microstrip low-pass filter will be presented for achieving high ability to choose wide stopband and suitable operation. This filter is built after design and simulation, and results of measurement will confirm the design accuracy. The results show that the overall performance of the recommended structure is improved in terms of physical dimensions, sharpness of response, and width of stopband, compared to old structures. Cut-off frequency of filter is 1.1 GHz. The stopband is so wide, and the amount of weakness in this band is equal to −20 dB. Roll-off rate parameter of the proposed filter is equal to 240 dB/GHz. This means that changing filter condition moves rapidly from passing to stop state. Size of proposed filter is small and equal to 27 mm × 16 mm. Results of simulation and measurement of the fabricated sample exhibit the same reaction. [ABSTRACT FROM AUTHOR]

In this paper, a new approach based on an improved fractal dimensions (FDs) for an iris recognition system is proposed. Improved FDs, based on a differential box-counting (DBC) method were extracted from horizontal coefficients, vertical coefficients, and diagonal coefficients in different levels, by discrete wavelet transform. The CASIA iris images database was used to evaluate the algorithm; the simulation results are very promising. [ABSTRACT FROM AUTHOR]

The stepped‐impedance combline band pass filter (BPF) with novel input and output networks based on a new proposed J‐inverter, which increases the center frequency tuning range with constant bandwidth (BW), is discussed. The even and odd mode analysis shows that the stepped resonators provide the necessary conditions for the appropriate coupling coefficient to keep the BW constant. In order to create an appropriate quality factor, the new proposed J‐inverter is used. In the frequency response of the stopband region, three transition zeros (TZs) are generated, which two of TZs are controllable. The proposed tunable BPF has been fabricated on RO4003 substrate with a dielectric constant of 3.38 and 0.813 mm thickness. The size of the filter is compact and is only 0.31λg×0.1λg$$ 0.31{\lambda}_{\mathrm{g}}\times 0.1{\lambda}_{\mathrm{g}} $$, where λg$$ {\lambda}_{\mathrm{g}} $$ is the guided wavelength at the lower center frequency. The center frequency is equal to 1.723 GHz and a frequency tuning range from 1.2 GHz to 2.246 GHz with 100 MHz constant 3 dB absolute BW, the insertion loss of 1.4–3.17 dB and return loss of 17.8–25.9 dB is achieved. [ABSTRACT FROM AUTHOR]