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The objective of this paper is to minimize both the makespan and the total completion time. Since parallel-machine scheduling which contains the function constraint problem has been a new issue, this paper explored two parallel-machine scheduling problems with function constraint, which refers to the situation that the two machines have a same function but one of the machines has another. We pointed out that the function constraint occurs not only in the manufacturing system but also in the service system. For the makespan problem, we demonstrated that it is NP-hard in the ordinary sense. In addition, we presented a polynomial time heuristic for this problem and have proved its worst-case ratio is not greater than 5/4. Furthermore, we simulated the performance of the algorithm through computational testing. The overall mean percent error of the heuristic is 0.0565%. The results revealed that the proposed algorithm is quite efficient. For the total completion time problem, we have proved that it can be solved in O n 4 time. [ABSTRACT FROM AUTHOR]

Abstract: For the estimation of the frequency of a complex sinusoid, previous methods interpolate DFT coefficients to obtain the frequency offset. Most of these interpolation methods can be considered as linear approximation of a nonlinear function. Up to date, only a few previously proposed estimators have been shown to have analytical expressions. In this paper, we show that almost all the interpolated estimators proposed to date, both direct and iterative, have simple analytical solutions for the frequency offset. Thus, the estimation bias of these estimators can be better understood and a whole new set of unbiased estimators using the analytical solutions is also introduced. [Copyright &y& Elsevier]

Abstract: Frequency estimation for single tone complex sinusoid is a fundamental problem in signal processing. A simple and effective way is to directly interpolate the discrete Fourier transform (DFT) coefficients around the peak of the magnitude spectrum. In this paper, we use theoretical analysis to show that correcting a phase term on the DFT coefficients before interpolation can reduce the estimation bias and improve the accuracy of the estimation significantly. We derive the amount of bias reduction that can be achieved by the phase correction. We then show that the phase correction can be considered as a pre-estimation correction while the effect of the previously proposed post-estimation correction is also to reduce the bias caused by the phase. In the experiments, we find that the phase correction proposed here and the post-estimation correction previously proposed is effective in different regions of frequency offset. We theoretically derive the threshold between the regions and propose a hybrid estimator which uses different corrections in different regions of frequency offset. Experiments show that the hybrid estimator is superior among direct estimators across the entire range of frequency offset at moderate and high SNR. [Copyright &y& Elsevier]

Abstract: Volume rendering is an important tool to visualize three-dimensional data in biomedicine by projecting the data to a two-dimensional plane. The projection is done by ray casting and its complexity is proportional to the number of three-dimensional data points. To reduce complexity, Fourier volume rendering (FVR) uses slice projection theorem to facilitate the integration of voxels along the ray casting path. In this paper, we proposed a new method for FVR that stored and processed the frequency domain data in polar coordinate. By exploiting three aspects of data processing which is previously impossible in rectilinear coordinate, our new method is much faster than the previous methods. The first aspect is data regularity. When data are stored in polar coordinate, extracting a slice involves accessing data stored in adjacent memory location. This regularity makes memory access more efficient. The second aspect is to utilize the high data density near the origin in polar coordinate. We can obtain two benefits from this aspect. The first allows us to extract a slice by nearest-neighbor interpolation instead of more complex interpolation but without sacrificing image quality. The second allows us to trade off between image quality and memory storage. The third aspect is to recognize that converting from rectilinear coordinate to polar coordinate is a one-time process. Therefore, we can use a better interpolation kernel with larger support in coordinate conversion. In turn, most of the computation is shifted to the preprocessing stage and interactive rendering can be made very fast. In the experiments, we show that the speed in interactive visualization for our new method is independent of the size of the interpolation kernel, therefore, achieving comparable image quality at a faster rate than previous methods. [Copyright &y& Elsevier]

Abstract: Stereoscopic MRA acquires a pair of blood vessel projections at two different viewing angles. Previously, we have developed two algorithms to reconstruct 3-D blood vessels from stereoscopic MRA. The assumption we made was that blood vessels were tilting circular tubes and the shape of the vessel on every cross-section was an ellipse. Since an ellipse can be represented in either algebraic form or parametric form, our previous algorithms reconstructed the ellipses by representing them in these two forms. In this paper, we further improved the accuracy of our previous algorithms by an order through two enhancements. The first improvement we made was a better method to estimate the rotation angle of the major axis of an ellipse. Instead of using the center of two adjacent ellipses to estimate the rotation angle as in our previous method, the new method used the projection lengths of the two views to estimate the angle. The second improvement we made was the equation to describe the relationship between the major/minor axes and the projection lengths. In our experiments, the average estimation error for the parametric algorithm was improved from 0.471 pixels to 0.066 pixels. The average error for the algebraic algorithm was improved from 0.101 pixels to 0.014 pixels. [Copyright &y& Elsevier]

The distinct feature of data acquisition for magnetic resonance imaging (MRI) is that the data are sampled in frequency domain instead of spatial domain. Therefore, the acquired data must be inverse Fourier transformed to generate images. To apply fast Fourier transform (FFT), the data are usually acquired on rectilinear grids. However, acquiring data on rectilinear grids is not very efficient in MRI. A spiral trajectory, which starts at the origin of the frequency domain and spins out to higher spatial frequency is more efficient and faster than the conventional method. Since the spiral trajectories do not sample on rectilinear grids, raw data must be re-interpolated onto rectilinear grids prior to inverse FFT. This re-gridding process is done using a reconstruction program. When the platforms to run the program grow, the efforts required to maintain the program become prohibitive. This problem can be solved through the platform-independent Java programming language. In this paper, we report on our attempt to implement the spiral MRI reconstruction program in Java. We show that the performance is not significantly affected and that it is practical to use a platform-independent reconstruction software. [Copyright &y& Elsevier]

Presents information on a study which described real-time image reconstruction for spiral magnetic resonance imaging (MRI) using fixed-point calculation. Reconstruction algorithm for spiral MRI; Issues concerning fixed-point representations; Conclusions.

Among image halftoning algorithms, direct binary search (DBS) minimizes the total squared perceived error instead of using heuristic approaches. Therefore, it can generate halftone output with the best quality. The limitation of DBS is that its halftone pattern is controlled by the autocorrelation filter, which corresponds to both the human visual system and the printer model. Because of the low-pass characteristics of the filter, DBS can only generate blue-noise-like halftone pattern and the only variation is the clustered-dot algorithm proposed in 2013. We use the results of theoretical bounds to show that halftone patterns in DBS can be controlled in both frequency and spatial domains through an approach called "noise shaping." This approach is achieved through an added term to the filtered error in DBS. We also show that DBS clustered-dot halftoning is a special case of this noise-shaping approach. Experimental results show that both the spatial-domain and frequency-domain characteristics of the generated halftone pattern can be manipulated freely using this approach. [ABSTRACT FROM AUTHOR]

Abstract: Kernel-based nonlinear characteristic extraction and classification algorithms are popular new research directions in machine learning. In this paper, we propose an improved photometric stereo scheme based on improved kernel-independent component analysis method to reconstruct 3D human faces. Next, we fetch the information of 3D faces for facial face recognition. For reconstruction, we obtain the correct normal vector’s sequence to form the surface, and use a method for enforcing integrability to reconstruct 3D objects. We test our algorithm on a number of real images captured from the Yale Face Database B, and use three kinds of methods to fetch characteristic values. Those methods are called contour-based, circle-based, and feature-based methods. Then, a three-layer, feed-forward neural network trained by a back-propagation algorithm is used to realize a classifier. All the experimental results were compared to those of the existing human face reconstruction and recognition approaches tested on the same images. The experimental results demonstrate that the proposed improved kernel independent component analysis (IKICA) method is efficient in reconstruction and face recognition applications. [ABSTRACT FROM AUTHOR]

In many scheduling studies, researchers consider the processing times of jobs as constant numbers. This assumption sometimes is at odds with practical manufacturing process due to several sources of uncertainties arising from real-life situations. Examples are the changing working environments, machine breakdowns, tool quality variations and unavailability, and so on. In light of the phenomenon of scenario-dependent processing times existing in many applications, this paper proposes to incorporate scenario-dependent processing times into a two-machine flow-shop environment with the objective of minimizing the total completion time. The problem under consideration is never explored. To solve it, we first derive a lower bound and two optimality properties to enhance the searching efficiency of a branch-and-bound method. Then, we propose 12 simple heuristics and their corresponding counterparts improved by a pairwise interchange method. Furthermore, we set proposed 12 simple heuristics as the 12 initial seeds to design 12 variants of a cloud theory-based simulated annealing (CSA) algorithm. Finally, we conduct simulations and report the performances of the proposed branch-and-bound method, the 12 heuristics, and the 12 variants of CSA algorithm. [ABSTRACT FROM AUTHOR]

Highlights: [•] The level histogram is used with the K-means algorithm for clustering data. [•] The fast K-means algorithm was effectively applied to image database sets. [•] The fast K-means algorithm improved the efficiency of the traditional K-means algorithm. [•] The fast K-means algorithm processed images efficiently as images increases. [•] The selection of the initial cluster centers affected the performance. [ABSTRACT FROM AUTHOR]

Recently, neuronal correlates of acupuncture stimulation in human brain have been investigated by functional neuroimaging. The preliminary findings suggest that acupuncture at analgesic points involves the pain-related neuromatrix and may have acupoint–brain correlation. Although multiple models of control stimulations have been applied to address the specificity of the needling effect clinically, their impacts have not been evaluated by functional neuroimaging. With the advantage of objective parameter setting, electroacupuncture (EA) was used in this study to devise three distinct controls for real EA, i.e., mock EA (no stimulation), minimal EA (superficial and light stimulation), and sham EA (same stimulation as real EA) applied at nonmeridian points. Fifteen healthy volunteers received real EA at analgesic point Gallbladder 34 (Yanglinquan), sham EA, and one of either mock EA or minimal EA over the left leg in counter-balanced orders. Multisubject analysis showed that sham EA and real EA both activated the reported distributed pain neuromatrix. However, real EA elicited significantly higher activation than sham EA over the hypothalamus and primary somatosensory–motor cortex and deactivation over the rostral segment of anterior cingulate cortex. In the comparison of minimal EA versus mock EA, minimal EA elicited significantly higher activation over the medial occipital cortex. Single-subject analysis showed that superior temporal gyrus (encompassing the auditory cortex) and medial occipital cortex (encompassing the visual cortex) frequently respond to minimal EA, sham EA, or real EA. We concluded that the hypothalamus–limbic system was significantly modulated by EA at acupoints rather than at nonmeridian points, while visual and auditory cortical activation was not a specific effect of treatment-relevant acupoints and required further investigation of the underlying neurophysiological mechanisms. [Copyright &y& Elsevier]