Shifting Method Research Articles

An Effective Multiple-Bit Data Abstraction and Lossless Retrieval without Shifting

Cryptography and Steganography are two major forms of enforcing data privacy, with the former being prevalent. For small payloads, Steganography is preferred, as the data remains concealed and abstracted. The process involves embedding bits onto a carrier image. However, the disadvantage of steganography is that the carrier image gets distorted, which is a major concern when it comes to pixel sensitive images, such as forensic and medical images that aremission critical. Furthermore, due to modifications in the pixel values, the images get distorted, which can be irrecoverable. Hence, the technique of Reversible Data Hiding(RDH) can be used as a solution. Usually two methods are used under RDH, namely Histogram Shifting (HS) and Difference Expansion (DE). Histogram Shifting method shifts all pixel values between pairs of peak and zero points, which allows data to be embedded in the intermediate points. However, this method also depends on frequencies of pixel values on the image, andthe embedding capacity varies greatly on the image. In Difference Expansion Method, the difference between a pixel and its adjacent pixels is considered to embed a single bit intoone of the pixels. Here, a scheme to embed multiple bits in a pixel is proposed, which greatly enhances the embedding capacity. Initially, three horizontally adjacent pixels are takenand the difference between the rightmost and leftmost pixel iscalculated. This difference is used to classify the centre pixel as embeddable or non-embeddable. If the pixel is embeddable, anew pixel value is calculated, which comprises of the secret bits, offset bits and flag bits, without the use of any difference expansion or histogram shifting process. The secret bits and the original pixel value can be easily recovered from the modified value using the offset and flag bits. This scheme has higher embedding capacity, and lower complexity in terms of computations, when comparedwith other RDH schemes.

Automatic Shifting Method for the Identification of Generalized Radial Flow Parameters by Water Cycle Optimization

Automatic Shifting Method for the Identification of Generalized Radial Flow Parameters by Water Cycle Optimization

A numerical modelling of a multi-layer LaFeCoSi Active magnetic regenerator by using Artificial Neural Networks

• Artificial Neural Networks are included into an active magnetic regenerator model. • The analytical formulation of the new numerical model is evidenced. • Artificial Neural Networks improve the evaluation of magnetocaloric properties. • The new model shows a better accuracy than the previous one. One of the main problems in the framework of magnetic refrigeration regards low adiabatic temperature changes that occur in the magnetocaloric materials, which limits the widespread application of this technology. Therefore, the major effort of researchers is focused on the development of multi-layer Active Magnetic Regenerators, which allows to enlarge the temperature span of a magnetic refrigerator. The use of numerical models can help to understand the feasibility of such application with less effort in comparison with the use of experimental facilities. One of the main challenges in designing a numerical model of a multi-layer Active Magnetic Regenerator is the effective incorporation of the magnetocaloric data of different magnetocaloric materials, which are fundamental to correctly optimize the configuration of such a device with the aim to improve its performance. These data are usually obtained experimentally from different measurements and their integration into the numerical model is challenging. Therefore, this work proposes a modified multi-layer Active Magnetic Regenerator numerical model based on Artificial Neural Networks to integrate the magnetocaloric properties of magnetocaloric materials, allowing an easier and a more reliable implementation of the real properties of magnetocaloric materials. The proposed model was tested simulating a four-layer and a seven-layer LaFeCoSi Active Magnetic Regenerator. The use of Artificial Neural Networks to integrate the magnetocaloric properties of magnetocaloric materials into the multi-layer Active Magnetic Regenerator allowed to improve the accuracy of the model in comparison with the commonly used technique (i.e., Curie temperature shift method) when compared to the experimental data. Indeed, the maximum error of the maximum temperature span with zero thermal load was reduced from about 13 K to 6.6 K , for the seven-layer configuration, and from about 4.1 K to 1.0 K , for the four-layer configuration. Furthermore, the new model allows to obtain more reliable simulated data about the effectiveness of each layer of the Active Magnetic Regenerator, providing a more useful tool to discuss about the optimization of its configuration. The results shows that Artificial Neural Networks can be successfully applied for integrating the magnetocaloric properties of magnetocaloric materials into a multi-layer Active Magnetic Regenerator numerical model, improving its performance. They represent an innovative way to address the problem of including magnetocaloric properties into numerical models, opening the way to other possible Machine Learning techniques as alternatives to the usual Curie temperature shifting method used in the literature to date.

Effect of relative humidity on the linear viscoelastic properties of asphalt mixtures

It has been demonstrated that humidity, or water vapor, is a non-negligible contributor to moisture damage of asphalt pavements. However, little work has been done regarding the effect of humidity on the performance of asphalt mixtures. The objective of this paper was to investigate the linear viscoelastic (LVE) properties of asphalt mixtures under different humidity conditions. Specimens were first conditioned at four humidity levels and subsequently employed to perform dynamic modulus tests. Next, a shifting method for the master curve under humidity conditions was proposed to quantify the influence of water vapor on LVE properties of asphalt mixtures. Finally, the effect of humidity on LVE properties of asphalt mixtures was analyzed based on three aspects. The results show that the developed shift method is accurate enough to quantify the effect of humidity on master curves of asphalt mixtures since the error in any group is less than 2%, while each R2 value exceeds 0.98. The rheological parameter Ee decreases, and R and m increase as the humidity levels rise. However, no obvious variation trend was found in the Eg, k, and fc of different groups. The humidity factor g(Hi) shows a negative increasing trend based on the rise in humidity levels. Meanwhile, according to the developed three-dimensional master curves of dynamic modulus and phase angle of the two types of mixtures, dynamic modulus decreases and phase angle increases as humidity levels rise at low frequencies (or high temperatures). No significant differences were observed on dynamic modulus and phase angle among different groups at high frequencies. Thus, the developed three-dimensional dynamic modulus and phase angle master curves can determine dynamic modulus and phase angle under arbitrary humidity conditions.

Generalized Relay Shifting Method for System Identification

Generalized Relay Shifting Method for System Identification

Process Identification Using Relay Shifting Method for Auto Tuning of PID Controller

The paper describes the use of a recently introduced relay shifting method for estimation parameters of a second order time delayed model. The aim is to obtain a process model for setting PID control parameters. For this purpose, an algorithm is designed for estimation of model parameters from two frequency response points obtained from a single relay feedback test without any assumptions about a model transfer function. The relay shifting method is slightly modified here by using an integrator to receive the frequency response points in positions more suitable for model fitting. This modification enables to better estimate the static gain even under constant load disturbance. The proposed solution is demonstrated on simulated examples.

Detection of Faint Asteroids Based on Image Shifting and Stacking Method

In order to improve the ability to find the faint and small celestial bodies in the solar system, a method of shifting and stacking images which improves the detection efficiency of faint moving objects is applied to process the sequential optical images. This method determines the existence of moving objects by using the method of false position to pre-estimate the apparent velocities of moving objects, then determines iteratively the accurate positions of moving objects based on the SNR (Signal-to-Noise Ratio) and elongation of stellar image. Using the sequential images of the China Near Earth Object Survey Telescope (CNEOST), we carry out an experiment and succeed in detecting asteroids fainter than 21 magnitude which are invisible on a single image. Thus, the feasibility of this method is verified.

Simulation based Performance Analysis of Histogram Shifting Method on Various Cover Images

Simulation based Performance Analysis of Histogram Shifting Method on Various Cover Images

Comparative Analysis of Image Hiding Approach in Encrypted Domain Based on Histogram Shifting Method

Comparative Analysis of Image Hiding Approach in Encrypted Domain Based on Histogram Shifting Method

Integrated Model of Image Protection Techniques

We propose an integrated model of Block-Permutation-Based Encryption (BPBE) and Reversible Data Hiding (RDH). The BPBE scheme involves four processes for encryption, namely block scrambling, block-rotation/inversion, negative-positive transformation and the color component shuffling. A Histogram Shifting (HS) method is adopted for RDH in our model. The proposed scheme can be well suitable for the hierarchical access control system, where the data can be accessed with the different access rights. This scheme encrypts R, G and B components independently. Therefore, we can generate similar output images from different input images. Additionally, the key derivation scheme also provides the security according to the different access rights. Our scheme is also resilient against brute-force attacks and Jigsaw Puzzle Solvers (JPSs). Furthermore, the compression performance is also not severely degraded using a standard lossless compression method.

Cogging Torque Reduction in Line Start Permanent Magnet Synchronous Motor

Cogging torque has a negative impact on the operation of permanent magnet machines by increasing torque ripple, speed ripple, acoustic noise and vibration. In this paper Magnet Shifting Method has been used as a tool to reduce the cogging torque in inset Line Start Permanent Magnet Synchronous Motor (LSPMSM). It has been shown that Magnet Shifting Method can effectively eliminate several lower-order harmonics of cogging torque. In order to implement the method, first the expression of cogging torque is studied based on the Fourier analysis. An analytical expression is then introduced based on Permanent Magnet Shifting to reduce cogging torque of LSPMS motors. The method is applied to some existing machine designs and their performances are obtained using Finite Element Analysis (FEA). The effect of magnet shifting on pole mmf (magneto motive force) distribution in air gap is discussed. The side effects of magnet shifting on back-EMF, core losses and torque profile distortion are taken into account in this investigation. Finally the experimental results on two prototypes 24 slot 4 pole inset LSPMS motors have been used to validate the theoretical analysis.

Shape Measurement and Reconstruction of Solar Concentrator Based on Two-dimensional Phase Shift Method

Deflectometry is used to measure the three-dimensional profile of the solar concentrator because of its high accuracy and short inspection time. In order to obtain the shape of concentrator, two different phases usually have to be computed for a single area. The two phases are calculated by using two sets of the phase-shifting patterns with two-different directions, respectively. In this paper, a new two-dimensional phase shifting method is proposed to obtain two phases with different directions with a single set of 2D phase, which reduces the number of acquired images and increase measurement speed. On the other hand, it is necessary to acquire the shape, which must be calculated from the slopes of the measured object. Existing integration techniques have some drawbacks that render them unusable in many cases. An approximation employing radial basis functions is applied to reconstruct the shape of concentrator, and reconstructs surfaces both locally and globally with high accuracy. Finally, experiments in measuring the shape of RP3 mirror demonstrate the proposed method's performance.

Algorithm Design of 3D Measurement System Based on FPGA

Aiming at improving the 3D shape measurement speed and accuracy, the design of floating point algorithm for 3-D shape measurement using FPGA, is proposed. By using four-step phase shifting method for measuring 3D measurement system, using CORDIC algorithm to achieve phase calculation of the phase shift method, the algorithm is realized by Verilog language in FPGA, and to make simulation and verification in Modelsim. The study of 3D shape measurement system have a breakthrough from the design performance and hardware.Finally, the MATLAB simulation proved its effectiveness and viability.The experimental results show that the advantages of high data processing speed, high efficiency and high precision,etc.

Matrix representation of the shifting operation and numerical properties of the ERES method for computing the greatest common divisor of sets of many polynomials

The Extended-Row-Equivalence and Shifting (ERES) method is a matrix-based method developed for the computation of the greatest common divisor (GCD) of sets of many polynomials. In this paper we present the formulation of the shifting operation as a matrix product which allows us to study the fundamental theoretical and numerical properties of the ERES method by introducing its complete algebraic representation. Then, we analyse in depth its overall numerical stability in finite precision arithmetic. Numerical examples and comparison with other methods are also presented.

SU-E-J-22: Effect of MLC Leaf Width on MLC Leaf Shifting Algorithm for Concurrent Treatment of Prostate and Pelvic Lymph Nodes.

Our previous study showed that adjusting selected MLC leaf pairsto follow prostate movement is an effective strategy to account for daily prostate displacement during concurrent treatment with pelvic lymph nodes. MLC leaf width affects the quality of MLC shifting plans for longitudinal prostate motion compensation. This study is to investigate the effect of the MLC leaf width in compensation of the prostate movement. Fifty-one daily CT on-rail scans from three patients were available for this study. On these CTs, the prostate, bladder and rectum were manually contoured, and the lymph nodes contours were transferred from the planning CT after rigid bony registration. For each patient, three different IMRT plans were created based on a planning CT using leaf width of 2.5, 5, and 10 mm, respectively. For each CT, the prostate displacement was determined by dual imaging registration and compensated by shifting MLC resulting in a total of 153 MLC shifted plans. Among 51 daily CTs, the average prostate movement along the superior/inferior direction was 1.1±3.7 mm (range: -6 to 6.5 mm). The differences in D99 of the prostate between the dose of the day and dose of the plan were 2.3±3.3%, 1.3±2.0%, and 4.4±5.1% for 2.5, 5, and 10 mm leaf width plans, respectively (p<<0.05). The corresponding differences in D99 of the lymph nodes were 0.7±0.9%, 0.6±0.9%, and 1.4±0.8%. The mean differences in D50 were 0.8%, 1.6%, and 2.7% for the bladder, and 10.0%, 3.9%, and 5.7% for the rectum, respectively. Using the MLC Shifting method to compensate for prostate movement in the longitudinal direction depends on the MLC leaf width and the magnitude of the prostate motion. The use of leaf width of 5 mm can provide sufficient tumor coverage without significantly affecting doses to the critical structures.

The Multiplier Method for optimal control problems of parabolic systems

In this paper the application of the Multiplier Method (also known as Augmented Lagrangian Method or Penalty Shifting Method) to quadratic optimal control problems for linear parabolic distributed systems is studied and the convergence of the method on appropriate Hilbert spaces is proved. Numerical examples are reported.

Considerations of a Penalty Shifting Method for Nonlinear Programming Problems

Ordinary Lagrange function and penalty function methods are typical methods for solving nonlinear programing problems with constraints. The application of the ordinary Lagrange function method is in general limited to convex programing problems. The penalty function method can be applied to nonconvex programing problems, but may suffer from numerical difficulties. The penalty shifting method is superior to the above two methods, since it can be applied to nonconvex programing problems without suffering from numerical difficulties. In this paper two geometric interpretations for the penalty shifting method are mainly given, so that its characteristics may be more clarified. First, the correction rules of two parameters and the relation between one of the parameters and the existence of a saddle point are investigated by the ordinary geometric interpretation. Secondly, the operation of the parameters is also investigated by a new geometric interpretation, and finally, the result for a nonconvex programing problem is illustrated by two geometric interpretations.

Considerations of a Penalty Shifting Method for Nonlinear Programming

Considerations of a Penalty Shifting Method for Nonlinear Programming

On the Method of Multipliers for a Class of Distributed Parameter Systems

In this paper the application of the Multiplier Method (also known as Augmented Lagrangian Method or Penalty Shifting Method) to optimal control problems for linear parabolic distributed systems is studied; the convergence of the method on appropriate Hilbert spaces is proved.

A Penalty Shifting Method for Constrained Optimal Control Problems

A Penalty Shifting Method for Constrained Optimal Control Problems