An RL-based scheduling algorithm for video traffic in high-rate wireless personal area networks

The emerging high-rate wireless personal area network (WPAN) technology is capable of supporting high-speed and high-quality real-time multimedia applications. In particular, video streams are deemed to be a dominant traffic type, and require quality of service (QoS) support. However, in the current IEEE 802.15.3 standard for MAC (media access control) of high-rate WPANs, the implementation details of some key issues such as scheduling and QoS provisioning have not been addressed. In this paper, we first propose a Markov decision process (MDP) model for optimal scheduling for video flows in high-rate WPANs. Using this model, we also propose a scheduler that incorporates compact state space representation, function approximation, and reinforcement learning (RL). Simulation results show that our proposed RL scheduler achieves nearly optimal performance and performs better than F-SRPT, EDD + SRPT, and PAP scheduling algorithms in terms of a lower decoding failure rate.     

A fast quaternion wavelet-based motion compensated frame rate up-conversion with fuzzy smoothing: application to echocardiography temporal enhancement

In this paper, we propose a fast Frame Rate Up-Conversion (FRUC) method based on Quaternion Wavelet Transform (QWT) motion estimation to improve the motion estimation accuracy and reduce the computational complexity. The proposed method contains three key elements: motion estimation, motion post-processing, and motion compensated frame interpolation. This paper considers the QWT motion estimation using the phase of image sequences, which leads to more accurate motion estimation, less post-processing procedures, and low complexity as well. Moreover, we proposed a modified fuzzy vector mean filtering to cope with motion outliers and made use of bilateral motion vector modification in the post-processing part. We have assessed our proposed method performance using six widely available benchmark test sequences and three echocardiography image sequences. The evaluations confirm that while our proposed method keeps the PSNR and SSIM performance suitable, it is at least twice faster in comparison with reference methods on the benchmark dataset. The echocardiography evaluations reveal our proposed method superiority in terms of PSNR, SSIM, and computation time, which make the proposed method suitable as an echocardiographic-specific method.

     

Robust regulation and tracking system design for multivariable control of the tape transport mechanism

Tape mechanisms must be able to transport the tape with a constant velocity for achieving high rate of data transfer. In this paper, a multivariable model of tape transport mechanism including the take-up and supply reel servos for tape tension control and capstan servo for speed control is considered. To achieve desired performance, pole-placement approach based on general canonical control form (GCCF) is used. Instead of using expensive tension sensors, an observer is designed. A regulator system is developed for disturbance rejection; and a modified integral control is designed for perfect tracking of desired set-points in tape speed and tensions. Since the real dynamic model associates with parametric uncertainties, an algorithm is developed for robust pole-placement. Eigenvalues of the uncertain control system are chosen such that appropriate responses are achieved while control efforts remain small bounded. Results show that robust performance is obtained for uncertain models with various parametric uncertainties.     

Application of anodized titanium for enhanced recruitment of endothelial progenitor cells

Objectives

To study the efficacy of an effective anodized titanium surface with enhanced attachment of endothelial progenitor cell (EPC).

Background

In-stent restenosis is a major obstacle for vascular patency after catheter-based intravascular interventions. Recently, stents that capture EPCs have been paid attention in order to make a functional endothelialized layer at the site of stent-induced endothelial denudation. Anodized titanium has been shown to enhance stem cell attachment. Anodization is a quick and inexpensive method, which can provide suitable stent surface.

Methods

Surface topography was examined by high-resolution scanning electron microscopy (SEM). Substrates were co-cultured with EPCs at second passage in 24-well culture plates. Evaluation of cell growth, proliferation, viability, surface cytotoxicity and cell adhesion was performed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test and 4,6-diamidino-2-phenylindole dihydrochloride staining. For platelet attachment, platelets added to substrates were evaluated under SEM.

Results

The average MTT values for tissue culture polystyrene plate, unanodized and anodized titanium with nanostructure were equal to 0.49, 0.16 and 0.72, respectively (P < 0.05). The surface had no cytotoxic effects on cells. The average cell attachment results showed that 9,955 ± 461.18, 3,300 ± 197.98 and 11,359 ± 458.10 EPCs were attached per well of tissue culture polystyrene plate, unanodized and anodized titanium surfaces, respectively (P < 0.05).

Conclusions

Anodized titanium surfaces can be potentially applied for devices that need enhanced recruitment of EPCs. This unique property makes these anodized surfaces good and cheap candidates for designing cardiovascular medical devices as endovascular stents.     

Evaluation of 12 models to estimate hourly diffuse irradiation on inclined surfaces

This study evaluates the performance of 12 models to estimate hourly diffuse solar irradiation on inclined surfaces from those measured on horizontal surfaces. Total solar irradiation incident on a tilted surface consists of three components including: beam, diffuse and reflected from the ground. On a semi-hourly basis, the beam component can be calculated by the ratio of the incidence angle to the solar zenith angle. The reflected component has a small effect on calculations and may be calculated with an isotropic model. In contrast, models for estimating the diffuse component show major differences, which justify the validation study that this paper discusses. Twelve models were tested against recorded south- and west-facing slope irradiances at Karaj (35°55^′N; 50°56^′E), Iran. The following models were included: Badescu [Ba], Tian et al. [Ti], Perez et al. [P9], Reindl et al. [Re], Koronakis [Kr], Perez et al. [P8], Skartveit and Olseth [SO], Steven and Unsworth [SU], Hay [Ha], Klucher [Kl], Temps and Coulson [TC], and Liu and Jordan [LJ].The relative root mean square error (RMSE), for the south-facing surface ranges from 10.16% to 54.89% for the SO and TC models, respectively. For the west-facing surface, RMSE ranges from 30.71% for the P9 model to 63.53% for the TC model. Statistical indices show that all models produce large errors for the west-facing surface. Statistical indices for the south-facing surface show reasonably good agreement with measured data.     

A Hybrid Higher Order Neural Classifier for handling classification problems

In this paper, we propose a novel Hybrid Higher Order Neural Classifier (HHONC) which contains different high-order units. In contrast with conventional fully-connected higher order neural networks (HONN), our proposed method uses fewer learning parameters and allocates the best fitted model in dealing with different datasets by modifying the orders of different high-order units and updating the learning parameters. Structure, model selection and updating the learning parameters of HHONC is introduced and is applied in classification of the Iris data set, the breast cancer data set, the Wine recognition data set, the Glass identification data set, the Balance scale data set, and the Pima diabetes data set. Acquired results are compared with the methods presented in Chen and Shie (2009). It is observed that the fewer features the dataset contains, the more accurate the HHONC performs, however the accuracy of datasets with more features are acceptable. Experimental results show about 3.5% and 0.6% improvements compared to the best accuracy obtained in previously methods for classifying the Pima diabetes and Iris datasets, respectively. In addition, by using a same method for reducing the feature number, it’s shown the proposed method perform more accurate than methods presented in Shie and Chen (2008). In this case, improvements compared to the best acquired accuracy of mentioned methods are about 1.7%, 1.3% and 0.2% in classification of Pima, Iris and Breast cancer datasets, respectively.     

Frequency Range Determination for Reflectometry System in Alborz Tokamak Using 2D FDTD Simulation

Reflectometry is a plasma diagnostic technique similar to radar. Microwaves are lunched into the plasma and reflected at the critical surfaces. By receiving the reflected microwave signals and comparing them with the lunched waves, the plasma density profile and its fluctuations can be obtained. Multiple-fixed-frequency reflectometry is one of the methods which considered determining Alborz Tokamak plasma cut off layers position and plasma density profile. In order to design components of the reflectometer, the main parameter which should exactly be determined, is the range of microwave frequency. For the mentioned purpose, a 2D code is used to simulate plasma profile reconstruction in Alborz Tokamak. The code uses the finite-difference-time-domain method with a perfectly-matched-layer absorption boundary to solve Maxwell’s equations. A 1D formula also is used to verify values resulted from the simulation. The good agreement between calculated and simulated values shows the high accuracy of the simulation. With respect to the simulation results, the appropriate range of frequency is determined and the reflectometer components can be designed according to this frequency range.     

Simultaneous design of parameters and controller of robotic manipulators: closed loop approach to practical implementation

In this paper, Simultaneous Design of Plant parameters and Controller (SDPC) of robotic manipulators is presented using the Closed Loop (CL) optimal control approach. Since a robot is inherently used to perform repetitive tasks, the SDPC problem for robotic manipulator systems is practically reformulated as the optimal balancing problem and a demonstration of practical implementation. The optimality conditions are derived using the CL-optimal control theory and then solved by the policy iteration method. The modified policy iteration is further used to design robot parameters. The results are compared with the Open Loop (OL) solution through the optimal and static balancing cases. As a final point, although OL is the exact solution, but it has higher control cost over the CL implementation (for the case implemented here the cost difference is 16.75%). Also CL-case has much shorter calculation time (51%) than that of the OL case.     

Vacuum enhanced membrane distillation for trace contaminant removal of heavy metals from water by electrospun PVDF/TiO<Subscript>2</Subscript> hybrid membranes

Electrospun hybrid membranes were synthesized using electrospinning of Poly (vinylidenefluoride) - titanium tetraisopropoxide (PVDF-TTIP) sol. Asymmetric post-treatment of membrane conducted for deprotonation of titanate and making hydrophilic/hydrophobic dual characteristics. The membranes were characterized by various methods such as wettability, scanning electron microscopy, infrared spectroscopy, X-ray diffraction and liquid entry pressure tests. For evaluating the separation performance, these membranes were applied in the VMD process to treat water heavy metal contaminants. The effects of operating parameters such as flow rate, temperature and membrane properties as porosity, on contaminant removal and producing ultra-pure water have been studied.