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Beam Scanning Using Integrated Microstrip Ferrite Phase shifter
No full textFerrite phase shifters are widely used to control the radiation properties of phased array antennas. The design and performance of a microstrip array antenna with integrated ferrite phase-shifter is described. Calculated tunable differential phase shift and simulated beam scanning properties of the linear phased array antenna is presented and corroborated with measured result
A Novel Arabic Text Steganography Method Using Letter Points and Extensions
Get PDFThis paper presents a new steganography approach suitable for Arabic texts. It can be classified under steganography feature coding methods. The approach hides secret information bits within the letters benefiting from their inherited points. To note the specific letters holding secret bits, the scheme considers the two features, the existence of the points in the letters and the redundant Arabic extension character. We use the pointed letters with extension to hold the secret bit ‘one’ and the un-pointed letters with extension to hold ‘zero’. This steganography technique is found attractive to other languages having similar texts to Arabic such as Persian and Urdu. Keywords — Arabic text, Cryptography, Feature coding, Information security, Text steganography, Text watermarking
Thermodynamic Analysis of Thermoelectric Device
Get PDFIn this work, the thermoelectric diode is considered and electronic as well as Carnot efficiency of the device are computed. It is found that increasing emitter temperature increases the Carnot efficiency of the device; in which case, diode power intensity and electronic efficiency reduce. The second law efficiency increases with emitter to collector temperature ratio and reduces with increasing collector temperature due to increase in collector current flow
Parallelizing GF(P) Elliptic Curve Cryptography Computations for Security and Speed
Get PDFThe elliptic curve cryptography can be observed as two levels of computations, upper scalar multiplication level and lower point operations level. We combine the inherited parallelism in both levels to reduce the delay and improve security against the simple power attack. The best security and speed performance is achieved when parallelizing the computation to eight parallel multiplication operations. This strategy is worth considering since it shows very attractive performance conclusions
Decentralized, Self-organizing, Potential field-based Control for Individually-motivated, Mobile Agents in a Cluttered Environment: A Vector-Harmonic Potential Field Approach
No full textAbstract—Spatial multiagency has been receiving growing attention from researchers exploring many of the aspects and modalities of this phenomenon. The aim is to develop the theoretical background needed for a multitude of applications involving the sharing of resources by more than one agent. A traffic management system is one of these applications. Here, a large group of mobile robots that are operating in communication-limited, and sensory-limited modes are required to cope with each others presence as well as the contents of their environment while preserving their ability to reach their preset independent goals. This paper explores the construction of a decentralized traffic controller for a large group of agents sharing a workspace with stationary forbidden regions. The suggested multiagent motion controller is complete provided that a lenient condition on the geometry of the workspace is upheld. It has a low computational effort that linearly increases with the number of agents. The controller is also self-organizing; therefore, it is able to deal, on its own, with incomplete information and unexpected situations. In addition to the above, the controller has an open structure to enable any agent to join or leave the group without the remaining agents having to adjust the manner in which they function. To meet these requirements, a definition of decentralization is suggested. This definition equates decentralization to self-organization in a group of agents operating in an artificial-life mode. The definition is used to provide guidelines for the construction of the multiagent controller. The controller is realized using the potential field approach. Theoretical developments, as well as simulation results are provided
Identification of errors-in-variables model with observation outliers based on Minimum-Covariance-Determinant
Get PDFIn this paper, we develop a subspace system identification algorithm for the errors-in-variables (EIV) model subject to observation noise with outliers. By using the minimum covariance determinant (MCD), we identify and delete the outliers, and then apply the classical EIV subspace system identification algorithms to get state space models. In order to solve the MCD problem for the EIV model we propose a random search algorithm. The proposed algorithm has been applied to a heat exchanger data
Dynamic Performance of a Wind Generation System with Thyristor Controlled Capacitor Compensation
Get PDFA dynamic model of a variable speed cage machine wind generation unit, including wind profile, wind turbine, induction generator, local load and transmission line connecting the grid is developed. The steady state as well as the dynamic performance of the wind energy system is explored. The performance of the system under wind gust conditions has been studied and the amount of transient injection to the grid investigated. A stabilizing control scheme which minimizes the transient injection through a thyristor controlled variable capacitance at the generator terminal is explored. PI controller with optimized gain settings is included in the control loop. The ‘optimal’ parameters of the PI controller are obtained through a pole-placement technique. The PI controlled variable capacitance strategy has demonstrated very good damping profile for the wind turbine-generator power system
To Coalesce or Not To Coalesce
Get PDFSystem performance of Gigabit network hosts can severely be degraded due to interrupt overhead caused by heavy incoming traffic. One of the most popular solutions to mitigate such overhead is interrupt coalescing in which a single interrupt is generated for multiple incoming packets. This is opposed to normal interruption in which an interrupt is generated for every incoming packet. In this paper we investigate the performance of interrupt coalescing analytically and compare it with that of normal interruption. We consider two types of coalescing (viz. count-based and time-based). The system performance is studied in terms of throughput, CPU availability for user applications, latency, and packet loss
