Soliton-radiation trapping in gas-filled photonic crystal fibers

We propose an optical trapping technique in which a fundamental soliton traps an ultrashort small amplitude radiation in a symmetric hollow-core photonic crystal fiber filled with a noble gas, preventing its dispersion. The system is Raman- and plasma-free. Trapping is due to the cross phase modulation effect between the two pulses. The trapped radiation inside the soliton-induced potential will oscillate periodically due to the shock effect, similar to the motion of a mechanical pendulum. DOI: 10.1103/PhysRevA.87.04380

Trapped Bose-Einstein condensates in the presence of a current nonlinearity

We investigate the effect of a current nonlinearity on the evolution of a trapped atomic Bose-Einstein condensate. We have implemented techniques from the field of nonlinear optics to provide new insights into the irregular dynamics associated with chiral superfluids. We have found that the current nonlinearity can be treated as a Kerr-like nonlinearity modulated by a spatiotemporal function that can lead to a number of processes such as broadening and compression of the wave function. In the long time scale limit, the wave function is drastically deformed and delocalised compared to its initial state. However, localised modes which oscillate with the period of the inverse trap frequency can still be observed.Comment: A short note on the links between nonlinear gauge potentials and nonlinear optics. Comments are welcom

Soliton dynamics in gas-filled hollow-core photonic crystal fibers

Gas-filled hollow-core photonic crystal fibers offer unprecedented opportunities to observe novel nonlinear phenomena. The various properties of gases that can be used to fill these fibers give additional degrees of freedom for investigating nonlinear pulse propagation in a wide range of different media. In this review, we will consider some of the the new nonlinear interactions that have been discovered in recent years, in particular those which are based on soliton dynamics

A computer vision system for the classification of moving object

The aim of this research is to produce a system that can detect the moving object and classify it into three classes: “Humans, Vehicle and Animals”. Using fixed video camera in outdoors environment, the system will capture the images and digitize them using (Piccolo Pro II) frame grabber at a rate of 25 frames per second. The Background Subtraction technique has been employed in the work as it is able to provide the most complete feature for data. However, it is extremely sensitive to dynamic changes like changing of illumination. Background Subtraction is done by taking the differenc e between any frame and the background in detecting the Moving Object. In order to reduce the effect of noise pixels resulting from the Background Subtraction operation, a number of pre-processing methods have been applied on the detected moving object. These preprocessing operations involve the use of median filter as well as morphological filters. Then the outline of the object will be extracted using border extraction technique. The classification makes use of both the shape and the dynamic features of the objects. In increasing the performance of the classification, all features are sequentially arranged so that the goal of this research is to be achieved. In this work, the performance achieved is 93% for class human, 93% for class vehicle and 64% for class animal

Efficient selective encryption schemes to secure video data and moving objects information for HEVC/H.265 using advanced encryption standard / Mohammed Ahmed Mohammed Saleh

Due to the huge growth in communication and digital technologies in support of multimedia sharing, video security has recently attracted the attention of researchers. Since video data representation takes up a large amount of data, it has to be minimized before being transmitted through the channels. To do so, that data has to be subjected to a compression process. This process is performed according to the video coding standard (video compression). There have been different types of video coding standards, but High Efficiency Video Coding (HEVC) is the latest video coding standard being introduced. Whereas, in the field of video security, there are several types of encryption algorithms utilized by researchers, such as Rivest- Shamir-Adleman (RSA), Data Encryption Standard (DES) and Advanced Encryption Standard (AES). All of those encryption algorithms are classified as asymmetric and symmetric algorithms. Since the video data is still huge even after the compression process, most researchers apply their encryption approaches on a selective part of the video data whereas the compression process is performed by a different type of coding standard. Most of the existing video encryption methods are not adequate to secure the video contents against the modern security attacks and eavesdropping. Furthermore, those methods have become impractical especially for the video sharing through the internet using the new coding standard HEVC because of the limited resources on the devices

Efficient selective encryption schemes to secure video data and moving objects information for HEVC/H.265 using advanced encryption standard / Mohammed Ahmed Mohammed Saleh

Due to the huge growth in communication and digital technologies in support of multimedia sharing, video security has recently attracted the attention of researchers. Since video data representation takes up a large amount of data, it has to be minimized before being transmitted through the channels. To do so, that data has to be subjected to a compression process. This process is performed according to the video coding standard (video compression). There have been different types of video coding standards, but High Efficiency Video Coding (HEVC) is the latest video coding standard being introduced. Whereas, in the field of video security, there are several types of encryption algorithms utilized by researchers, such as Rivest-Shamir-Adleman (RSA), Data Encryption Standard (DES) and Advanced Encryption Standard (AES). All of those encryption algorithms are classified as asymmetric and symmetric algorithms. Since the video data is still huge even after the compression process, most researchers apply their encryption approaches on a selective part of the video data whereas the compression process is performed by a different type of coding standard. Most of the existing video encryption methods are not adequate to secure the video contents against the modem security attacks and eavesdropping. Furthermore, those methods have become impractical especially for the video sharing through the internet using the new coding standard HEVC because of the limited resources on the devices. Wherein those approaches have fallen into some limitations, such as low-security level, high computational overhead, not maintaining the bitstream compliance and result in the increase of video bitrate. In this thesis, three lightweight selective encryption approaches have been developed to provide a visual video and moving objects protection of HEVC bitstream that can be utilized for real-time video streaming, while maintaining the computational cost and video bit rate. Those approaches named as, Encryption for Absolute Coefficient Level, Encryption of Intra Prediction Mode, and Encryption of Motion Vector Difference (MVD). In the first and second methods, the visual video information is secured by encrypting limited transformed coefficients using AES algorithm. Whereas the third method is dedicated to secure the moving object information in the video by exploiting the syntax element of motion vector difference, and this method is encrypted by AES as well. The experimental results for the first and the second of the proposed approaches has shown that a reliable security level of visual video perception was provided, in addition to having no observed effects on compression efficiency. Furthermore, from the test results of the third method, the moving objects information was encrypted and at the same time, the compression efficiency was maintained. The proposed schemes provide a trade-off between encryption reliability, flexibility, and computational complexity, where the encryption time in the first scheme increased by 13% and zero in the second and the third schemes, and the increase in bitrate is 1% in the first and the third schemes and zero in the second scheme. Thus, these methods can be considered as feasible techniques to secure the HEVC/H.265 bitstream, and can be applied in real-time applications

A Dynamic Assimilation Model: Selected First-generation Arab-canadians

The dissertation examines the process of Arab assimilation in Canada. Data was gathered by bilingual (Arabic/English) questionnaires. The author used a multidisciplinary approach to present assimilation as a process of psychosocial spatial transformation.;The contribution of the dissertation is a molecular assimilation model which integrates three parts: spatial interaction, assimilation and identity change. The model parts are totally interrelated allowing for dynamic feedbacks, multicyclic operation and continuous transformation. The application of the model led to a greater appreciation of the molecular and dynamic nature of assimilation.;Assimilation molecularity is recognized by discovering the assimilation molecules: intercultural events. They are the interacting subsystems that combine into an infinity of dynamic combinations/parts: adjustment, acculturation, integration, diffusion...etc. Using the concept of molecularity a new, comprehensive and simple definition is proposed: assimilation is the psychosocial spatial outcome of the aggregate effects of dynamic intercultural events.;Assimilation dynamism is the rule that governs assimilation progression, behaviour, stages, and configuration. Assimilation progression is time-sensitive, uneven and non linear. Assimilation behaviour is variable and multidirectional. Assimilation stages are heterogeneous consisting of dissimilar events. Assimilation configurations are relative not absolute.;Because of its molecular and dynamic characteristics, the model shifts attention from surface appearances (the consequences) to the hidden interacting subsystems: assimilation events (the molecular processes). Future assimilation studies may focus on the structural, interactional, temporal, spatial and hierarchial dimensions of the assimilation events. An interdisciplinary team of psychologists, sociologists and geographers may work together to carry out laboratory investigations on the assimilation events. This should be an interesting and rewarding line of inquiry

Photonic circuits for generating modal, spectral, and polarization entanglement

We consider the design of photonic circuits that make use of Ti:LiNbO$_{3}$ diffused channel waveguides for generating photons with various combinations of modal, spectral, and polarization entanglement. Down-converted photon pairs are generated via spontaneous optical parametric down-conversion (SPDC) in a two-mode waveguide. We study a class of photonic circuits comprising: 1) a nonlinear periodically poled two-mode waveguide structure, 2) a set of single-mode and two-mode waveguide-based couplers arranged in such a way that they suitably separate the three photons comprising the SPDC process, and, for some applications, 3) a holographic Bragg grating that acts as a dichroic reflector. The first circuit produces frequency-degenerate down-converted photons, each with even spatial parity, in two separate single-mode waveguides. Changing the parameters of the elements allows this same circuit to produce two nondegenerate down-converted photons that are entangled in frequency or simultaneously entangled in frequency and polarization. The second photonic circuit is designed to produce modal entanglement by distinguishing the photons on the basis of their frequencies. A modified version of this circuit can be used to generate photons that are doubly entangled in mode number and polarization. The third photonic circuit is designed to manage dispersion by converting modal, spectral, and polarization entanglement into path entanglement

Cardioprotective Activity of Costus Root Ethanol Extract in Experimentally-Induced Hypothyroidism in Female Albino Rats

Hypothyroidism is a popular endocrine disorder caused by a thyroid hormone deficit. Changes in the state of the thyroid gland significantly affect many organs, including the heart. This study examined the cardioprotective effects of an artificially induced hypothyroidism in female rats using an ethanol extract from the root plant Saussurea lappa (Costus). For the current study, 25 adult female albino rats were employed. They were split into five equal groups, including control, hypothyroid group, post-treatment group with costus extract, co-administered hypothyroid group with costus extract, and post-treatment group with levothyroxine. Thyroid hormones (T3, T4, and TSH), lipid profile, and oxidative stress indicators (catalase, superoxide dismutase, reduced glutathione, and lipid peroxidation levels) were also measured in the serum. The heart muscle was the subject of a histological research. The findings suggested that Costus root ethanol extract improved hypothyroidism in female rats, as proven by the reversal of many biochemical abnormalities and improvements in the heart's histology. Our study indicates that the root of Costus exhibited cardioprotection efficiency against hypothyroidism-induced serious effects on the heart, The antioxidant and radical-scavenging properties of its components may be responsible for this promising effect