Search

Lack of temperature sensation of myoelectric prosthetic hand limits the daily activities of amputees. To this end, a non-invasive temperature sensation method is proposed to train amputees to sense temperature with psychophysical sensory substitution. In this study, 22 healthy participants took part besides 5 amputee participants. The duration time of the study was 31 days with five test steps according to the Leitner technique. An adjustable temperature mug and a Peltier were used to change the temperature of the water/phantom digits to induce temperature to participants. Also, to isolate the surroundings and show colors, a Virtual Reality (VR) glass was employed. The statistical results conducted are based on the response of participants with questionnaire method. Using Chi-square tests, it is concluded that participants answer the experiment significantly correctly using the Leitner technique (P value

Mechanomyography (MMG) has become a promising method for pattern recognition in upper-limb prostheses because mechanical signals can overcome the inherited unreliable drawbacks of the bioelectric electromyography (EMG) and electroencephalogram (EEG). However, the existing multi-channel pattern recognition methods require multi-site MMG because it is difficult to extract enough useful features from a single-site MMG. Therefore, this paper proposes a multi-channel finger pattern recognition using a single-site MMG signal. First, multi-mode high-dimensional features are extracted from the MMG signals, including statistical features, frequency-domain features, and acoustic features; second, the extracted features are further used for the pattern recognition using artificial neural networks (ANNs). In this study, 14 participants, including 6 males (3 athletes, 3 non-athletes), 6 females (3 athletes, 3 non-athletes) and 2 male amputees (wrist amputation and unilateral transradial) participated in the experiments. The real-time results show that the mean classification accuracy was 95.1% with 2.6 standard deviations (SDs) over the test folds (male athletes), 89.9%, 88.6% with 3.1, 3.7 SD (male non-athletes and female athletes, respectively) and 77.6% and 74.4% with 9.3 and 11.4 SD, respectively (wrist amputation, unilateral transradial) for seven movements. The results show that the proposed method has the capability to individually control fingers.

In many low-temperature areas, the environmental factor is an important limiting factor for the production and distribution of horticultural plants. This study aimed to investigate the cold tolerance of the male catkins and inoculated female flowers to screen the popular native hazelnut cultivars in Qazvin under low-temperature stress. A completely randomized factorial block design with three replications was used in this experiment with eight cultivars (Nakhnroud, Khandan, Mish-Pestan, South of Qarabagh, Asl-e-Qarabagh, Rasmi, and Gerdashkevar). After removing each of the treated samples at the end of the experiment, the samples were examined morphologically (appearance) and compared with the control. The changes were recorded as qualitative traits. To understand the influence of cold stress on reproductive organs, hydrogen peroxide and proline were measured. The results showed the onset of freezing in unopened male catkins at -7 and -9 °C and in inoculated female flowers at -3 °C. Damage to unopened male catkins' tissue occurred at -11 °C and in female flowers at -5 °C. The highest value observed among cultivars in the case for proline content of male catkins was in Mish-Pestan and Khandan cultivars with 0.816 and 0.660 µmol/ g FW, respectively. In inoculated female flowers, Mish-Pestan and Tabestaneh cultivars with 0.185 and 0.168 µmol/ g FW, respectively, showed the highest statistically significant increase in proline content. Interestingly, the cultivars with the highest proline content in male catkins indicated the most increase in H2O2; Mish-Pestan and Khnadan with 0.569 and 0.541 ug/g FW, respectively. Asl-eQarabagh was observed to have the least H2O2 content (0.042 ug/g FW) among cultivars. Again, in inoculated female flowers, those with the highest concentration of proline (Mish-Pestan and Tabestaneh) were found to have the highest H2O2 content (0.335 and 0.331 ug/g FW, respectively

Cardiovascular disease is now under the influence of several factors that encourage researchers to investigate the flow of these vessels. Oscillation influences the blood circulation in the volume of red blood cells (RBC) strongly. Therefore, in this study, its effects have been considered on hemodynamic parameters in the elastic wall and coronary bifurcation. In this study, a 3D geometry of non-Newtonian and pulsatile blood circulation is considered in the left coronary artery bifurcation. The Casson model with various hematocrits is analyzed in elastic and rigid walls. The wall shear stress (WSS) cannot show the stenosis artery alone, therefore, the oscillatory shear index (OSI) is represented as a hemodynamic parameter of WSS individually of time. The results are determined using two-way fluid-structure interaction (FSI) coupling method using an arbitrary Lagrangian-Eulerian method. The most prominent difference in velocity happened in the bifurcation and at hematocrit 30 with yield stress 6.59E-04 Pa. The backflow and vortex flow in the LCx branch grown with increasing shear rates. The likelihood of plaque generation at the ending of the LM branch is observed in hematocrits 10 and 20, while the WSS magnitude is normal in the hematocrit 60 with the greatest yield stress in the bifurcation. The shear stress among the rigid and elastic models is the highest at the ending of the LM branch. The wall shear stress magnitude among the models decreased at most of 24.49% by dividing the flow. Time-independent results for models showed that there is the highest value of OSI at the bifurcation, which then quickly dropped.

In this study, a three-dimensional analysis of the non-Newtonian blood flow was carried out in the left coronary bifurcation. The Casson model and hyperelastic and rigid models were used as the constitutive equation for blood flow and vessel wall model, respectively. Physiological conditions were considered first normal and then compliant with hypertension disease with the aim of evaluating hemodynamic parameters and a better understanding of the onset and progression of atherosclerosis plaques in the coronary artery bifurcation. Two-way fluid-structure interaction method applying a fully implicit second-order backward Euler differencing scheme has been used which is performed in the commercial code ANSYS and ANSYS CFX (version 15.0). When artery deformations and blood pressure are associated, arbitrary Lagrangian-Eulerian formulation is employed to calculate the artery domain response using the temporal blood response. As a result of bifurcation, noticeable velocity reduction and backflow formation decrease shear stress and made it oscillatory at the starting point of the LCx branch which caused the shear stress to be less than 1 and 2 Pa in the LCx and the LAD branches, respectively. Oscillatory shear index (OSI) as a hemodynamic parameter represents the increase in residence time and oscillatory wall shear stress. Because of using the ideal 3D geometry and realistic physiological conditions, the values obtained for shear stress are more accurate than the previous studies. Comparing the results of this study with previous clinical investigations shows that the regions with low wall shear stress less than 1.20 Pa and with high OSI value more than 0.3 are in more potential risk to the atherosclerosis plaque development, especially in the posterior after the bifurcation.

This paper presents development of the spectral element method (SEM) for analysis of circular and annular circular plates vibration under impact load. A novel formulation is proposed in frequency domain for conducting spectral element matrix. Several numerical examples are presented in order to demonstrate performance of the presented method compared to other numerical methods in literature. The presented formulation was applied in order to analyze vibration of annular circular plates with various thicknesses and various internal-to-external radius ratios. In addition, annular circular plate displacements subjected to an impact load were calculated using the presented SEM.

This paper presents development of the spectral element method (SEM) for the vibration analysis of thin shallow shells with rectangular planform subjected to impact loads. Dynamic formulation was developed for a thin shallow shell with two opposite edges simply supported and the other two edges with arbitrary boundary conditions. The SEM for such a shell was formulated in the frequency domain. Comparison studies were performed to assess the performance of the presented method. The effect of boundary conditions of the shallow shells is discussed in this paper. Shallow shell displacement subjected to impact load was calculated using the presented SEM.

In this study, two new moment resisting connections of beams to precast concrete columns under lateral load were analyzed via application of nonlinear finite element analysis software ABAQUS 6.10. The precast connections considered were the beam-column connections in which precast beams is connected to continuous precast column with corbel using (i) inverted E (bolted connection) and (ii) box section (welded connection). Connection responses associated with lateral resistance, lateral stiffness, ductility, and energy dissipation were compared to a reference monolithic connection. Achieved lateral resistance, lateral stiffness and ductility of the proposed connections was approximately 98%, 80% and 80% of the equivalent monolithic connection, respectively. The effect of axial load on column and compressive strength of concrete on behavior of the connections were studied. The analytical results show that the performance of two proposed precast connections were close to the performance of corresponding monolithic connection.

This paper presents a novel hybrid method coupling artificial neural network (ANN) and simulated annealing (SA), called ANN/SA to predict the fraction of pyrite remaining and therefore the pyrite oxidation rate in the wastes at different depths of a coal washing pile in the Alborz Markazi Coalfield, in northeast Iran. Waste depth, oxygen mole fraction and initial pyrite content in the waste particles were used as inputs to the network. The output of the network was the amount of pyrite content remaining. An ANN/SA model with Levenberg-Marquardt algorithm and a 3-4-3-1 arrangement showed a great capability. The network was used to predict the pyrite content remaining at two trenches E and F over the study waste pile once it was trained with the field-measured data. Simulated results obtained by the ANN/SA model were very closer to the experimental data compared to the outputs of simple ANN and multivariable least squares regression methods. The correlation coefficient (R) value, by the ANN/SA model, was 0.999 for training set, and in testing stage it was 0.998 and 0.99957 for trench E and trench F respectively which shows the model prediction was quite satisfactory. The performance of the model on the training and testing data, mean squared error (MSE) and mean absolute percent error (MAPE), indicate that it has both good predictive ability and generalisation performance.

Summary In this study, hybrid models are designed to predict groundwater inflow to an advancing open pit mine and the hydraulic head (HH) in observation wells at different distances from the centre of the pit during its advance. Hybrid methods coupling artificial neural network (ANN) with genetic algorithm (GA) methods (ANN–GA), and simulated annealing (SA) methods (ANN–SA), were utilised. Ratios of depth of pit penetration in aquifer to aquifer thickness, pit bottom radius to its top radius, inverse of pit advance time and the HH in the observation wells to the distance of observation wells from the centre of the pit were used as inputs to the networks. To achieve the objective two hybrid models consisting of ANN–GA and ANN–SA with 4-5-3-1 arrangement were designed. In addition, by switching the last argument of the input layer with the argument of the output layer of two earlier models, two new models were developed to predict the HH in the observation wells for the period of the mining process. The accuracy and reliability of models are verified by field data, results of a numerical finite element model using SEEP/W, outputs of simple ANNs and some well-known analytical solutions. Predicted results obtained by the hybrid methods are closer to the field data compared to the outputs of analytical and simple ANN models. Results show that despite the use of fewer and simpler parameters by the hybrid models, the ANN–GA and to some extent the ANN–SA have the ability to compete with the numerical models.

Single-shaft gas turbine and its cycles are sensitive to frequency drops and, therefore, sudden change loads or large frequency dips might affect their stability. This phenomenon is related to the reduction of the air mass flow passing through the machine during the frequency dips, which might lead to an interaction between governor and temperature control loop. In this paper, the performance of the combined cycle and steam-injected gas turbine are studied during frequency dips and transient maneuvers. For this purpose, two similar units are developed based on these cycles and their performances are studied in different scenarios. The simulation results show that the steam injected gas turbine has a better performance during frequency drops and it can handle relatively larger change loads.

This paper presents development of the spectral element method (SEM) to specify natural frequencies and dynamic response of moderately thick rectangular plates under impact and moving loads. To solve differential equations of moderately thick plate, the displacement field has been expressed in the frequency domain using Fast Fourier Transformation (FFT) algorithm while considering simple boundary conditions for two parallel edges. Closed-form solutions have been derived for the differential equations in frequency domain. Deriving exact shape functions of plate in frequency domain, the dynamic solution in time domain has been calculated using Inverse Fast Fourier Transformation (IFFT). In this study, natural frequencies for moderately thick plates with variable and constant thicknesses have been calculated and compared to the past research results. Mode shapes of plates with various boundary conditions have been plotted. Moreover, plate’s displacements under impact and moving loads have been calculated using developed SEM. The utilization of a minimum numbers of elements in SEM, consequently leading to a considerable decrease in computational costs, is the main advantage of this method.

A simple one-dimensional analytical solution is presented to model oxygen diffusion through the pore space of mine spoils containing pyrite. The model incorporates volumetric oxygen consumption terms due to pyrite oxidation, oxidation of Fe 2+ to Fe 3+ and bacterial activity. Based on this analytical solution, a graphical user interface (GUI) tool is programmed and designed in MATLAB software. This tool can be used to model transport of oxygen through the mine spoils either with or without a cap. Results of several simulation scenarios of sensitivity analysis showed a significant change in oxygen concentration with varying effective diffusion coefficient of oxygen transport model and simulation time. Efficiency and flexibility of the tool developed here is verified by modelling oxygen transport through the pore space of a coal waste pile (case A) and a copper mine tailings (case B). Maximum depth of oxygen diffusion is obtained approximately equal to 2 and 1.5 m through the cases A and B, respectively.

A dynamic model was developed for long-term simulation of a heavy duty gas turbine. The model includes the essential control algorithm of the gas turbine as well as the most common outputs and other important intermediate variables. Control algorithm details, such as wind up protection and load limiter algorithm which have large effect on gas turbine transient behavior, are included. The model parameters are identified by applying genetic algorithm and least squares algorithm on regular operational data from a real plant to better match the model response to the real plant. The simulation results have been validated with real plant data and shown to have valid accuracy for many engineering applications.

Recently, creating security in multimedia systems involving video has become one of the main needs in commercial and military usages. The most important traits of video frames are simultaneousness of frames and high volume of information. Considering these features, A5/1 and W7 stream ciphers are used for video main frames in the field of selective encryption of each DCT transform coefficient.In addition, a suitable method is expressed in order to select the encryption method of DCT transform coefficients by the stream algorithms. The simulation results of MATLAB software show that this method is suitable for multimedia security in terms of both security and execution speed of the algorithm.

In recent years, security of multimedia systems such as image and video has become one of the main needs in computer and communication networks. To encrypt multimedia content, lightweight and fast algorithms are usually used in frequency transform domain and in a partial encryption form, having time efficiency, high execution speed and correspondence with compression structures. In this article, a lightweight and fast algorithm is proposed and two designs in partial encryption scheme of DCT transform coefficients are introduced based on three fundamental principles and confrontation the partial encryption attacks (cryptographic attack, replacement attack and statistical model based attack). Moreover, the proposed algorithm is compared with A5/1 and W7 stream ciphers. The results of analyses and simulations by MATLAB software show that the proposed encryption algorithm and two introduced designs are applicable for real-time security applications of multimedia which require high-speed computations and sufficient security levels.

Single-shaft gas turbines are sensitive to frequency changes which might affect the grid stability during large frequency drops. This paper presents a new control system that uses steam injection as an auxiliary input to improve the transient performance of the gas turbine during frequency drops. Steam injection is beneficial because it reduces the peak temperature in the combustion chamber and augments the output power by increasing the mass flow through the turbine. The use of this auxiliary input is based on the event-based control approach. It means that during the frequency drop, the controller exploits the steam injection to help the main control loop recover the frequency and when the frequency reaches its predefined value, the system will return to its normal operation. The performance of the proposed control algorithm is investigated under different scenarios and the results show that the application of steam injection improves the performance of the regular control algorithm significantly, especially near full load condition.

The groundwater inflow into a mine during its life and after ceasing operations is one of the most important concerns of the mining industry. This paper presents a hydrogeological assessment of the Irankuh Zn-Pb mine at 20 km south of Esfahan and 1 km northeast of Abnil in west-Central Iran. During mine excavation, the upper impervious bed of a confined aquifer was broken and water at high-pressure flowed into an open pit mine associated with the Kolahdarvazeh deposit. The inflow rates were 6.7 and 1.4 m(3)/s at the maximum and minimum quantities, respectively. Permeability, storage coefficient, thickness and initial head of the fully saturated confined aquifer were 3.5 × 10(-4) m/s, 0.2, 30 m and 60 m, respectively. The hydraulic heads as a function of time were monitored at four observation wells in the vicinity of the pit over 19 weeks and at an observation well near a test well over 21 h. In addition, by measuring the rate of pumping out from the pit sump, at a constant head (usually equal to height of the pit floor), the real inflow rates to the pit were monitored. The main innovations of this work were to make comparison between numerical modelling using a finite element software called SEEP/W and actual data related to inflow and extend the applicability of the numerical model. This model was further used to estimate the hydraulic heads at the observation wells around the pit over 19 weeks during mining operations. Data from a pump-out test and observation wells were used for model calibration and verification. In order to evaluate the model efficiency, the modelling results of inflow quantity and hydraulic heads were compared to those from analytical solutions, as well as the field data. The mean percent error in relation to field data for the inflow quantity was 0.108. It varied between 1.16 and 1.46 for hydraulic head predictions, which are much lower values than the mean percent errors resulted from the analytical solutions (from 1.8 to 5.3 for inflow and from 2.16 to 3.5 for hydraulic head predictions). The analytical solutions underestimated the inflow compared to the numerical model for the time period of 2-19 weeks. The results presented in this paper can be used for developing an effective dewatering program.

The idea of active networks has been emerged in recent years to increase the processing power inside the network. The intermediate nodes such as routers will be able to host mobile agents and many management tasks can be handled using autonomous mobile agents inside the network. One of the important limitations, which should be considered in active networks, is the restricted processing power of active nodes. In this paper, we define an optimal location problem for monitoring mobile agents in a scalable active network as a p-median problem, which is indeed a kind of facility location problem. The agents are responsible to monitor and manage the performance of all of the network nodes such that the total monitoring traffic overhead is minimized. Then we proposed two methods of finding an appropriate sub set of intermediate nodes for hosting mobile agents. In our first method, we have not considered the limited processing power of active nodes, which host mobile agents. In our second method, we have solved the problem so that the processing loads of host nodes do not exceed a predefined threshold. Since p-median problems are NP-complete and the search space of these problems is very large, our methods are based on genetic algorithms. We have tested our two methods for finding mobile agents optimal locations on four network topologies with different number of nodes and compared the obtained location. By this comparison, we have shown the importance of considering processing load limitation for active nodes as a parameter in choosing them as hosts of mobile agents in a scalable active network. The proposed locations in our second method eliminates the probability of CPU overload in the active nodes hosting the mobile agents and reduces the processing time required for finding the optimal locations of mobile agents.

The advancement of technology has enabled new functions and possibilities for prosthetic devices. This advancement has introduced additional complexities for the user of the prosthetic devices. The added complexities can actually force the user to use simpler passive prosthesis rather than more complex and more flexible ones. This paper discussed the various aspects of the FUM Bionic Hand-I, designed and built at the Ferdowsi University of Mashhad. It also discusses the various efforts placed to simplify the usage of this prosthesis by its user. The FUM Bionic Hand-I has 5 degrees of freedom and consists of several sub systems such as pattern learning glove, wireless EMG Signal transmitter, RFID system for identify objects and a rich graphical user interface (GUI). These features works simultaneously in order to minimize the users' efforts on control a prosthetics hand and makes the hand intelligent enough to cooperate with user. Finally, the paper discusses the force control capability of the hand in order to allow object grasping.