With the advent of communication networks, the speed of data transmission has increased dramatically. One of the important factors in each transfer is to maintain data security and prevent unauthorized access to data transmitted. Using cryptography is one of the methods used to keep data secure throughout the transmission path. Today, with the growth of computer networks, the use of video conferencing, the transfer of military information, image data, the need for encryption of data in a variety of image data plays an important role. Encryption in images due to its specific features, such as the high volume of transmitted images, the amount of additional data for encryption, the correlation coefficient and the high repetition among the pixels, are very different from the text data; this has led to all traditional encryption methods It is not suitable for image data and there are changes in their structure to use traditional methods in image cryptography. In this paper, using pixel shift algorithms and Hill's encryption algorithm, ciphering of color images has been addressed; the pixel shift algorithm has been used to maintain greater dependency and security, and Hill's encryption algorithm has been used to change the amount of pixels. For analysis of the work, the algorithm is presented and for comparison with other methods, images and standard analysis methods have been used. The obtained results improve the efficiency of the proposed algorithm in comparison with the standard hail algorithm (especially in images with similar pixels) And compared with other comparable algorithms. تفاصيل المقالة

One of the structures made of photonic crystal is all-optic filter which these filters are widely used in optic telecommunications systems and networks. In this paper, a method has been presented to design an optic filter based on two-dimensional photonic crystals. The crystal which we suggested, was obtained by FDTD and PWE numeric methods, that influenced different parameters of output wavelength of filter. The result showed that increase of refraction index of Dielectric, leads information in output wavelength of filter. تفاصيل المقالة

Quantization watermarking is a technique for embedding hidden copyright information based on dithered quantization. This non-blind scheme is only practical for watermarking applications, where the original signal is available to the detector as for a fingerprinting purpose. The goal of this paper is to analyse the quantization watermarking in the three-dimensional wavelet transform. We consider the nonlinear effect of dithered quantization in the time-domain representation of the filter bank. We derive a compact and general form for distortion in the host video due to the encoding and embedding process. The formulation has the capacity to be simplified and optimized for different filter banks and dither signals. We provide some supporting experiments for the three-dimensional wavelet analysis of video signal. تفاصيل المقالة

One of looped networks that in recent years has been much noticed is standard known as IEEE 802.17 RPR ring network or the return packet. Architecture RPR ring network protocol that transmits data between nodes connected in a double ring structure to support. RPR has two single transit buffer structure (STB) and double transit buffer (DTB), respectively. Single transit buffer architecture, just a high-priority traffic buffering (HP) and low priority (LP) passing through the ring buffer architecture serves and double, two separate buffer for high-priority and low priority traffic is considered passing.Send information for scheduling algorithms used in network nodes RPR, queue priority (Priority-Queue), respectively. In this way, the separation of traffic based on priority and high priority traffic has absolute priority over lower priority traffic so that always the highest priority to transit buffer appropriated therefore of high priority traffic such as video packet, the nodes access to congested suffered numerous delays and instability vibration are ring (Jitter).In this thesis addition to scheduling priority queue, plans, schedules DRR and DRR + to increase the quality of service to traffic with high priority on congested node in a network with a ring structure with 10 nodes software Opnet simulation and the performance timing of passing information about at least two network nodes in the hub scenario (hUB) in which all the nodes transmit information to a node with video traffic conditions, congestion were examined happened and qualitative results were compared to that, the display shows the relative improvements in reducing delays and instability shaking changes in the timing of DRR and DRR + compared to the recommended standard. تفاصيل المقالة

The depth image plays an increasingly important role in fundamental research and daily applications, with the reducing the price and increasing the number of affordable and portable depth cameras. Infrared sensors or depth sensors are widely used to control dynamic and static 3D scenes. However, the depth image quality is limited to low-quality images, as the infrared sensor does not have high resolution. Therefore, given the problems and the importance of using 3-D images, the quality of these images should be improved in order to provide accurate images from depth cameras. In this paper a resolution enhancement method of depth images using convolutional neural networks is considered. A convolutional neural network with a depth of 20 and three layers and a pre-trained neural network is used. We developed the system and tested its performance for two datasets, Middlebury and EURECOM Kinect Face. Results show for EURECOM Kinect Face images, PSNR improvement is approximately 7 to 16 dB and for Middlebury images the PSNR improvement is about 6 to 12 dB. تفاصيل المقالة

Vehicular Ad-Hoc Networks (VANET) models are derived from Mobile Ad-Hoc Networks that possess an impressive role in the intelligent transportation system today and also in the future. So scientists are always looking for the best theories in hope of grasping the fastest and safest connections between vehicles, to provide traffic and accident news in real time. The high number of nodes is one of the significant features of this network that results in an increase of the number of transmitted packets in the network. Distributed system and high mobility of the nodes are the other most important attributes of Vehicular Ad-Hoc networks. In this paper, we aim to review the studies and improvements of vehicular Ad-Hoc network in the fields of safety and traffic management. In addition, we introduce the most common challenges of this network and gather latest methods for resolving those problems. Multi agent systems will be one of the newest and suitable tools in this system. The main purpose is arranging safe connection between agents. Fixing agreements and removing the disputes are not detachable from functional system. It is like group associations and societies which require human collaborations and cooperation. Development of science resulted in utilization of these systems in various aspects like VANET. Nowadays scientists and researchers are interested to make use of these methods for improving the role of vehicle networks in the field of traffic management, safety and entertainment, we will review them in the following paragraphs. تفاصيل المقالة

Recently, with the advent of cloud computing technology and the growth of cell phone applications, the technology has been introduced as a solution for use in smart phones. Combining cloud computing and smart phones copes with such obstacles as performance including battery life time, storage capacity and bandwidth, environment as scalability and availability, and security like reliability and accessibility. Today, patient information collection processes require extensive analysis on the collected input data. In addition, this process has lots of errors, it is affordable and increases the time needed for access to the data. These conditions constrain effective monitoring and diagnostic capabilities by the hospitals. Unlike previous methods, data can be collected by devices such as Bluetooth and stored on a server in hospital. In this paper, a comprehensive research involves collecting data from patients and sending this data to a smart phone. Therefore, two algorithms were proposed for a list of physicians with the highest priority. Priority parameters are received by the hospitals server. These priorities include the initial weight, the weight indicating how busy the physician is, and the relationship between physician and patient's disease. Android application was simulated by Eclipse software. The application includes a diagnostic system that receives patient data and compared it with the reference table. If the patient's condition is not good, a short message is sent using two mentioned algorithms. تفاصيل المقالة

Mobile robot navigation is one of the basic problems in robotics. In this paper, a new approach is proposed for autonomous mobile robot navigation in an unknown environment. The proposed approach is based on learning virtual parallel paths that propel the mobile robot toward the track using a multi-layer, feed-forward neural network. For training, a human operator navigates the mobile robot in some different paths in the environment. Both of human operator navigating data and virtual parallel paths train the neural network. The neural network is able to map the coordinate of a position to a mobile robot orientation and velocity. After training, the mobile robot can plan a track between start and target position without the need of any human operator. When the environment surrounding the mobile robot is unknown, sensors are used to detect obstacles and avoid collision. The simulated mobile robot is equipped with a rangefinder sensor. The simulation shows promising results and high speed for real-time implementation in unknown and partially dynamic environments. تفاصيل المقالة