Bøger af Iraj Sadegh Amiri

Distributed Denial of Service (DDoS) attack is one of the most disruptive attacks in computer networks. It utilizes legitimate requests from hundreds or thousands of computers to specific targets to occupy targets' bandwidth and deplete targets' resource. In this work, we have attempted to not only mitigate DDoS attacks but also identify the source of attacks even behind Network Address Translation (NAT). This is followed by remedial actions such as denying further access or informing them that they have participated in the attacks. This report presents a new algorithm to prevent servers from DDoS attacks. This algorithm requires that network routers or gateways collaborate with each other in order to detect suspicious traffic. The algorithm initiates a peer-to-peer communication among network routers or gateways to increase the probability of detecting unwanted traffic. We derive mathematical proofs based on cryptographic concepts such as birthday attacks to estimate the rate of attacks generated and passed along the routers. This implementation is to prevent the attacker from sending spam traffic to the server which can lead to DDoS attacks. The effectiveness of our implementation is evidenced in our experimental results.

Nowadays big organizations have complex administrative structure with scattered offices to face with serious problems related to key management like financial and security problems that based on symmetric encryption system. This project proposes an efficient solution related to symmetric key crypto system so that with solving this problem the organization can have a secure, affordable, efficient, easier and faster symmetric key crypto system. In symmetric key cryptography with the less key size have more secure in comparison to asymmetric cryptography. Therefore using symmetric key cryptography is more secure and Advantageous. The speed of processing symmetric cryptography is higher than asymmetric cryptography. The purpose of this project is to product the software who all of the employees in the organization can have the secret symmetric key cryptography so that they can communicate to each other with the secret key. However, the security of symmetric key cryptography is higher than asymmetric key cryptography. Among of many algorithm available, key derivations algorithm which used in this project is very important for symmetric cryptosystems because one key can be derived to the others. This Method is chosen by key derivation one-way function and implemented by Delphi programming language. Each organization which uses this implemented method the manager of the organization can generate the secret key for all of the employees and its employees has the symmetric secret key and if the employees need to communicate with each other their request should be sent to the manager. This project has been done in three phases and one of the outcomes of this project is a application which generates random key, according to hierarchy of organization.

The bacterial contaminated glove is the most important cause of bacteria transmission in health care and food industries. Manufacturing antimicrobial latex seems as a possible solution to prevent these contaminations. Due to bacterial drug resistance new effective antimicrobial drugs must be developed. Great progresses on nanoparticle-based antimicrobial latex requires to consider the shared interest between microbiologists and nanoengineers in developing novel nanotechnology targeting a few major unmet challenges of antimicrobial agents. The current brief book focuses on antimicrobial agents and also nanoparticles with antimicrobial properties have been discussed. Moreover antimicrobial latex and its biomedical applications have been reviewed.

Osteoporosis disease makes bone fragile and weak to withstand against load and bodyweight. Crack initiation and damage might occur depends on different morphological indices and types of load impose on trabecular bone. Fatigue analysis with strain-based method is applied for bovine trabecular bone with three different morphological indices to investigate correlation between fatigue life results and bone morphology. Two different analyses were performed, the first was static and the second was dynamic analysis. Axial load imposed on vertical, 45-degree and horizontal samples. Plastic strain in vertical sample initiated at 30% of total and reach to 5.97e-4 at 40% however, at 45-degree and horizontal initiated at 20% and 10% with values of 0.00479 and 0.211 respectively. Then fatigue analysis was performed on samples and S-N curve extracted. Results show that fatigue life of vertical sample at high load amplitude (40% of total load) is 12262 cycles, however this value in 45-degree and horizontal samples decrease drastically to 357 and 5 cycles respectively. In the various morphological indices, BV/TV and BS/TS are counted as crucial factor in correlation between fatigue life and bone morphology. Vertical sample include of less porosity than 45-degree and horizontal, and because of this reason stress localized and plastic strain value in vertical sample value is far below than other two. Fatigue life decrease when porosity of structure increases. Plastic strain and high stresses had been appeared in arch and rod-like of trabeculae.Non study consider contribution of rotated angle of load on fracture of trabeculae so far, in this study results show that the most fracture in inner sites of bone occur when load angle is perpendicular to trabeculae.

This book discusses the enhancement of efficiency in currently used solar cells. The authors have characterized different structures of the solar cell system to optimize system parameters, particularly the performance of the Copper-Tin-Sulphide solar cell using Solar Cell Capacitance Simulator (SCAPS). This research can help scientist to overcome the current limitations and build up new designs of the system with higher efficiency and greater functionality. The authors have investigated the corresponding samples from various viewpoints, including structural (crystallinity, composition and surface morphology), optical (UV-vis-near-IR transmittance/re¿ectance spectra) and electrical resistivity properties. Describes investigations on Cu2SnS3 solar cells and prospective low cost absorber layer of thin film solar cells;Discusses the potential device structure of Copper-Tin-Sulphide based on thin film technologies;Explains solar cell structure optimization to perform a higher conversion efficiency of Copper-Tin-Sulphide.

This book provides detailed and accurate information on the history, structure, operation, benefits and advanced structures of silicon MESFET, along with modeling and analysis of the device.

This book demonstrates the implementation of an automated measuring system for very efficient measurement of chromatic dispersion, which uses a modulation phase shift method over long haul of optical single mode fiber.

The purpose of this book was to investigate the temperature and input energy dependency of Nd:YAG laser performance pumped by flashlamp. A commercial laser rod Nd:YAG laser crystal was utilized as a gain medium. The laser rod was placed parallel to a linear flashlamp filled by xenon gas at 450 Torr. The Nd:YAG crystal together with the flashlamp was flooded with a coolant comprising of a mixture with 60% ethylene glycol and 40% distilled water, which covers a range of temperature from -30oC to +60oC. Spectroscopic properties of the Nd:YAG rod under pulsed flashlamp pumping was investigated from the output fluorescence spectrum of the flashlamp radiation and the Nd:YAG rod. The linewidth of each fluorescence line was measured for an estimation of an effective emission cross section and saturation intensity. The influence of temperature and input energy on a fluorescence emission cross section of Nd3+:YAG crystal was studied. The cross-section was found to decrease as the temperature and the input energy was increased. The inter-stark emission showed a Lorentzian line shape indicating homogeneous broadening. This was attributed to the thermal broadening mechanism of the emission line. The spectral widths and shifts of the emission lines for the three and four level inter-Stark transitions within the respective intermanifold transitions of 4F3/2→4I9/2 and 4F3/2→4I11/2 were investigated over the range of 0 to 75 J. The emission lines for the 4F3/2→4I9/2 transitions shifted towards a longer wavelength and broadened, while the positions and linewidths for the 4F3/2→4I11/2 transitions remained unchanged with the increase of input energy. Finally, the temperature dependence of quasi-three-level laser transitions for long pulse Nd:YAG laser was also investigated. The laser performances at both 938.5 nm and 946.0 nm were also found to be inversely proportional to temperature, and the slope efficiency was unchanged with temperature. The reduction was due to the mechanism of phonon scattering as well as a broadening effect while the temperature increased.

This book discusses analytical approaches and modeling of the breakdown voltage (BV) effects on graphene-based transistors.

This book focuses on the analysis and treatment of osteoporotic bone based on drug administration, tracking fatigue behavior and taking into consideration the mechanical interaction of implants with trabecular bone. Weak trabeculae are one of the most important clinical features that need to be addressed in order to prevent hip joint fractures.

This brief analyzes the characteristics of a microring resonator (MRR) to perform communication using ultra-short soliton pulses. The multi optical soliton with FWHM and FSR of 325 pm and 880 nm can be incorporated with a time division multiple access (TDMA) system wherein the transportation of quantum information is performed.

This Brief highlights different approaches used to create stable cellulase and its use in different fields. In order to improve its thermal stability, it can be engineered using a variety of approaches, such as hydrophobic interactions, aromatic interactions, hydrogen bonds, ion pairs and disulfide bridge creation.

The title explain new technique of secured and high capacity optical communication signals generation by using the micro and nano ring resonators.

In the frequency domain, MRRs can be used to generate optical millimetre-wave solitons with a broadband frequency of 0-100 GHz. The soliton carriers play critical roles to transmit the data via an optical communication link and provide many applications in secured optical communications.