619 research outputs found

    The Interpolating Random Spline Cryptosystem and the Chaotic-Map Public-Key Cryptosystem

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    The feasibility of implementing the interpolating cubic spline function as encryption and decryption transformations is presented. The encryption method can be viewed as computing a transposed polynomial. The main characteristic of the spline cryptosystem is that the domain and range of encryption are defined over real numbers, instead of the traditional integer numbers. Moreover, the spline cryptosystem can be implemented in terms of inexpensive multiplications and additions. Using spline functions, a series of discontiguous spline segments can execute the modular arithmetic of the RSA system. The similarity of the RSA and spline functions within the integer domain is demonstrated. Furthermore, we observe that such a reformulation of RSA cryptosystem can be characterized as polynomials with random offsets between ciphertext values and plaintext values. This contrasts with the spline cryptosystems, so that a random spline system has been developed. The random spline cryptosystem is an advanced structure of spline cryptosystem. Its mathematical indeterminacy on computing keys with interpolants no more than 4 and numerical sensitivity to the random offset t( increases its utility. This article also presents a chaotic public-key cryptosystem employing a one-dimensional difference equation as well as a quadratic difference equation. This system makes use of the El Gamal’s scheme to accomplish the encryption process. We note that breaking this system requires the identical work factor that is needed in solving discrete logarithm with the same size of moduli

    Symbolic Automation and Numerical Synthesis for Robot Kinematics

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    This research analyzes three topics in robot arm kinematics. First, the direct kinematics which determines the Cartesian position and orientation of the end effector for the specified values of joint parameters is analyzed. Second, the differential motions concerning the differential relationships between the command variables in position and orientation of the end effector and the joint-controlled variables are studied. Finally, the inverse kinematics which determines the joint variables for a specified Cartesian position and orientation of the end effector is considered. This dissertation presents a methodology for incorporating the artificial intelligence types of knowledge into automating solutions for the direct kinematics problem and the manipulator Jacobian matrix. Furthermore, the dissertation utilizes the backward recursive techniques, the trigonometric identity rules, and a set of heuristic rules for implementing this methodology. To expedite computation efforts, a new algorithm is developed to obtain a differential relationship of a robotic manipulator via the vector kinematics method. Moreover, the speed control model for general robotic manipulators, together with the inverse Jacobian regarding cases of under-determined and over-determined of joint-controlled variables, are also discussed. Three mathematical approaches are proposed for solving the inverse kinematics problem: the inverse homogeneous transformation matrices approach, the geometric approach, and the arm-wrist partitioned synthesis approach. The first two approaches yield the symbolic closed-form solutions; the last approach, based on the iterative technique, provides a maximum of 16 distinct solutions of joint motion variables for any given position and orientation of the end effector in the workspace

    Robot Pedagogics: The Adaptation, Analysis, and Computer Control of a Model Manipulator

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    The subject of robotics is addressed by many different fields, among them computer science, electrical engineering, and mechanical engineering. This work is an attempt to bring together all of these aspects from the perspective of a computer science background. Different techniques are considered and reconciled with one another in the analytical area, while detail and explanation are added in all areas that were not previously available. In addition, geometrical interpretations arc presented for concepts that have heretofore been presented only in the form of equations

    Industrial Simulation with Animation

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    This thesis examines and evaluates the new simulation language PCModel. Prior to the arrival of PCModel, simulation via computer typically resulted in pages of statistics compiled over the duration of the simulation. PCModel\u27s approach is to simulate the model on the display before the user in real time. Additionally, user interaction is supported to allow changes to be made throughout the simulation run. The evaluation of PCModel is accomplished through inspection of a pair of examples already simulated in a conventional simulation language. The examples show the relative strong and weak points of the language, as well as demonstrating how PCModel is used

    Computer control of a PBX washout plant

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    A fully automated, computer controlled plant has been designed specifically for safe removal of plastic bonded explosives (PBX) from obsolete military munitions. This PBX washout plant consists of a two stage delivery system and robotically operated high pressure waterjet lance. The assigned task was to develop control packages for each component. The first stage of the delivery system is a battery operated overhead trolley. Its control package consist of a dedicated computer, DC motor and custom positioning subprograms. The dedicated computer communicates through an infrared link to the operator\u27s computer. This link was developed due to requirements of a hazardous environment. Probable software solutions for the communication are presented given current system configurations. The trolley positions the munition directly above a hydraulically operated table - the second stage of the delivery system. This stage\u27s control package incorporates three closed loop, first order circuits and software. The table positions the munition for explosive removal by the waterjet. The robotic waterjet lance is hydraulically controlled through four closed loop, first order circuits. The concepts of its controlling software is presented to better understand the currently developed software

    An Analysis of Modern Cryptosystems

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    Since the ancient Egyptian empire, man has searched for ways to protect information from getting into the wrong hands. Julius Caesar used a simple substitution cipher to protect secrets. During World War II, the Allies and the Axis had codes that they used to protect information. Now that we have computers at our disposal, the methods used to protect data in the past are ineffective. More recently, computer scientists and mathematicians have been working diligently to develop cryptosystems which will provide absolute security in a computing environment. The three major cryptosystems in use today are DES, RSA, and the Knapsack Cryptosystem. These cryptosystems have been reviewed and the positive and negative aspects of each is discussed. A newcomer to the field of cryptology is the Random Spline Cryptosystem which is discussed in detail

    The Optimal Trajectory Modelling of Robot Manipulators

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    Greater robot capability can be achieved through the use of robot manipulator control systems. Crucial to the success of these control systems is the optimal trajectory modelling of the path traced by the end- effector. To create this optimal path the utilization of B-Spline curve functions will be investigated, and compared to Cubic Spline curve functions

    Alpha-Linolenic Acid-Enriched Butter Promotes Fatty Acid Remodeling and Thermogenic Activation in the Brown Adipose Tissue

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    Supplementation with n-3 long-chain (LC) polyunsaturated fatty acids (PUFA) is known to promote thermogenesis via the activation of brown adipose tissue (BAT). Agricultural products that are biofortified with α-linolenic acid (ALA), the precursor of n-3 LC PUFA, have been launched to the market, but their impact on BAT function is unknown. This study aimed to evaluate the effects of ALA-biofortified butter on lipid metabolism and thermogenic functions in the BAT. C57BL/6 mice were fed a high-fat diet containing ALA-biofortified butter (n3Bu, 45% calorie from fat) for ten weeks in comparison with the isocaloric high-fat diets prepared from conventional butter or margarine. The intake of n3Bu significantly reduced the whitening of BAT and increased the thermogenesis in response to acute-cold treatment. Also, n3Bu supplementation is linked with the remodeling of BAT by promoting bioconversion into n-3 LC PUFA, FA elongation and desaturation, and mitochondrial biogenesis. Taken together, our results support that ALA-biofortified butter is a novel source of n-3 PUFA, which potentiates the BAT thermogenic function

    Low-Power Complementary Inverter Based on Graphene/Carbon-Nanotube and Graphene/MoS<sub>2</sub> Barristors

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    The recent report of a p-type graphene(Gr)/carbon-nanotube(CNT) barristor facilitates the application of graphene barristors in the fabrication of complementary logic devices. Here, a complementary inverter is presented that combines a p-type Gr/CNT barristor with a n-type Gr/MoS2 barristor, and its characteristics are reported. A sub-nW (~0.2 nW) low-power inverter is demonstrated with a moderate gain of 2.5 at an equivalent oxide thickness (EOT) of ~15 nm. Compared to inverters based on field-effect transistors, the sub-nW power consumption was achieved at a much larger EOT, which was attributed to the excellent switching characteristics of Gr barristors
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