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71.
Pooneh Bagheri Zadeh Akbar Sheikh Akbari Tom Buggy John Soraghan 《Multimedia Tools and Applications》2010,49(2):347-370
In this paper a novel multiresolution human visual system and statistically based image coding scheme is presented. It decorrelates
the input image into a number of subbands using a lifting based wavelet transform. The codec employs a novel statistical encoding
algorithm to code the coefficients in the detail subbands. Perceptual weights are applied to regulate the threshold value
of each detail subband that is required in the statistical encoding process. The baseband coefficients are losslessly coded.
An extension of the codec to the progressive transmission of images is also developed. To evaluate the performance of the
coding scheme, it was applied to a number of test images and its performance with and without perceptual weights is evaluated.
The results indicate significant improvement in both subjective and objective quality of the reconstructed images when perceptual
weights are employed. The performance of the proposed technique was also compared to JPEG and JPEG2000. The results show that
the proposed coding scheme outperforms both coding standards at low compression ratios, while offering satisfactory performance
at higher compression ratios. 相似文献
72.
As a result of the emerging use of mesh-based multicomputers (and recently mesh-based multiprocessor systems-on-chip), issues
related to processor management have attracted much attention. In a mesh-based multiprocessor, after repeated submesh allocations
and de-allocations, the system network may be fragmented, i.e. there might be unallocated nodes in the network. As a result,
in a system with contiguous processor allocation, no new tasks can start running due to the lack of enough free adjacent processors
to form a suitable submesh. Although there might be enough free processors available, they remain idle until the allocator
can find a set of adjacent free nodes forming a submesh to be used for the new task. This can lead to low system performance.
Task migration was introduced as a solution to this problem through migration of tasks running on some submeshes to other
free areas in order to reduce fragmentation by chaining the newly freed areas and disengaging nodes to form larger submeshes.
In this paper, we propose a novel structured and formulated way to code task migration, which is helpful for congestion detection
in different steps of task migration algorithms. Moreover, considering the fact that the 3D mesh-based multicomputers are
now very popular, a new task migration algorithm in 3D meshes is proposed. We also address the special case of the 2D migration
in a 3D mesh multicomputer. 相似文献
73.
Mehdi Mohammadi Bijan Raahemi Ahmad Akbari Hossein Moeinzadeh Babak Nasersharif 《Expert systems with applications》2011,38(6):6417-6423
In this paper, we propose a hybrid approach using genetic algorithm and neural networks to classify Peer-to-Peer (P2P) traffic in IP networks. We first compute the minimum classification error (MCE) matrix using genetic algorithm. The MCE matrix is then used during the pre-processing step to map the original dataset into a new space. The mapped data set is then fed to three different classifiers: distance-based, K-Nearest Neighbors, and neural networks classifiers. We measure three different indexes, namely mutual information, Dunn, and SD to evaluate the extent of separation of the data points before and after mapping is performed. The experimental results demonstrate that with the proposed mapping scheme we achieve, on average, 8% higher accuracy in classification of the P2P traffic compare to the previous solutions. Moreover, the genetic-based MCE matrix increases the classification accuracy more than what the basic MCE does. 相似文献
74.
An optimal algorithm based on branch-and-bound approach is presented in this paper to determine lot sizes for a single item in material requirement planning environments with deterministic time-phased demand and constant ordering cost with zero lead time, where all-units discounts are available from vendors and backlog is not permitted. On the basis of the proven properties of optimal order policy, a tree-search procedure is presented to construct the sequence of optimal orders. Some useful fathom rules have been proven, which make the algorithm very efficient. To compare the performance of this algorithm with the other existing optimal algorithms, an experimental design with various environments has been developed. Experimental results show that the performance of our optimal algorithm is much better than the performance of other existing optimal algorithms. Considering computational time as the performance measure, this algorithm is considered the best among the existing optimal algorithms for real problems with large dimensions (i.e. large number of periods and discount levels). 相似文献
75.
Time delays are encountered in many physical systems, and they usually threaten the stability and performance of closed-loop systems. The problem of determining all stabilising proportional-integral-derivative (PID) controllers for systems with perturbed delays is less investigated in the literature. In this study, the Rekasius substitution is employed to transform the system parameters to a new space. Then, the singular frequency (SF) method is revised for the Rekasius transformed system. A novel technique is presented to compute the ranges of time delay for which stable PID controller exists. This stability range cannot be readily computed from the previous methods. Finally, it is shown that similar to the original SF method, finite numbers of singular frequencies are sufficient to compute the stable regions in the space of time delay and controller coefficients. 相似文献
76.
A. S. Ibraheam Y. Al-Douri J. M. S. Al-Fhdawi Hamid S. AL-Jumaili K. D. Verma U. Hashim R. M. Ayub A. Rahim Ruslinda M. K. Md Arshad A. H. Reshak S. B. Abd Hamid 《Microsystem Technologies》2016,22(12):2893-2900
The Cu2Zn1?xCdxSnS4 quinternary alloy nanostructures with different Cd contents were grown using spin coating technique on porous silicon (63.93 %) substrate. The structural properties of Cu2Zn1?xCdxSnS4/PS were investigated by X-ray diffraction and field emission-scanning electron microscope (FE-SEM). The optical properties studied through photoluminescence technique, indicated that the band gap is shifted as Cd content increases from 1.84 eV at x = 0 to 1.76 eV at x = 1. The electrical characterization of the Ag/n-PS/Cu2Zn1?xCdxSnS4/Ag diode through current to voltage (I–V) characterization shows the highest photo-response of (value if any) at Cu2Zn0.4Cd0.6SnS4 composition. 相似文献
77.
Hao Chen Juan He Raymond Lanzafame Istvan Stadler Hamid El Hamidi Hui Liu Jonathan Celli Michael R. Hamblin Yingying Huang Emily Oakley Gal Shafirstein Ho‐Kyoon Chung Shin‐Tson Wu Yajie Dong 《Journal of the Society for Information Display》2017,25(3):177-184
While OLEDs have struggled to find a niche lighting application that can fully take advantage of their unique form factors as thin, flexible, lightweight and uniformly large‐area luminaire, photomedical researchers have been in search of low‐cost, effective illumination devices with such form factors that could facilitate widespread clinical applications of photodynamic therapy (PDT) or photobiomodulation (PBM). Although existing OLEDs with either fluorescent or phosphorescent emitters cannot achieve the required high power density at the right wavelength windows for photomedicine, the recently developed ultrabright and efficient deep red quantum dot light emitting devices (QLEDs) can nicely fit into this niche. Here, we report for the first time the in‐vitro study to demonstrate that this QLED‐based photomedical approach could increase cell metabolism over control systems for PBM and kill cancerous cells efficiently for PDT. The perspective of developing wavelength‐specific, flexible QLEDs for two critical photomedical fields (wound repair and cancer treatment) will be presented with their potential impacts summarized. The work promises to generate flexible QLED‐based light sources that could enable the widespread use and clinical acceptance of photomedical strategies including PDT and PBM. 相似文献
78.
Mohammad Bagher Akbari HaghighatAuthor Vitae Hadi SeyedarabiAuthor Vitae 《Computers & Electrical Engineering》2011,37(5):744-756
The widespread usage of image fusion causes an increase in the importance of assessing the performance of different fusion algorithms. The problem of introducing a suitable quality measure for image fusion lies in the difficulty of defining an ideal fused image. In this paper, we propose a non-reference objective image fusion metric based on mutual information which calculates the amount of information conducted from the source images to the fused image. The considered information is represented by image features like gradients or edges, which are often in the form of two-dimensional signals. In this paper, a method of estimating the joint probability distribution from marginal distributions is also presented which is employed in calculation of mutual information. The proposed method is compared with the most popular existing algorithms. Various experiments, performed on several databases, certify the efficiency of our proposed method which is more consistent with the subjective criteria. 相似文献
79.
Sarve H Lindblad J Borgefors G Johansson CB 《Computer methods and programs in biomedicine》2011,102(1):25-34
Bone-implant integration is measured in several ways. Traditionally and routinely, 2D histological sections of samples, containing bone and the biomaterial, are stained and analyzed using a light microscope. Such histological section provides detailed cellular information about the bone regeneration in the proximity of the implant. However, this information reflects the integration in only a very small fraction, a 10 μm thick slice, of the sample. In this study, we show that feature values quantified on 2D sections are highly dependent on the orientation and the placement of the section, suggesting that a 3D analysis of the whole sample is of importance for a more complete judgment of the bone structure in the proximity of the implant. We propose features describing the 3D data by extending the features traditionally used for 2D-analysis. We present a method for extracting these features from 3D image data and we measure them on five 3D SRμCT image volumes.We also simulate cuts through the image volume positioned at all possible section positions. These simulations show that the measurement variations due to the orientation of the section around the center line of the implant are about 30%. 相似文献
80.
Mohamed Ahmed Hamid Harroud Roger Impey Ahmed Karmouch 《Multimedia Tools and Applications》2007,34(3):299-315
In this paper, we aim to provide adaptive multimedia services especially video ones to end-users in an efficient and secure
manner. Users moving outside the office should be able to maintain an office-like environment at their current locations.
First, the agents within our proposed architecture negotiate the different communication and interaction factors autonomously
and dynamically. Moreover, we needed to develop a user agent in addition to service and system agents that could negotiate
the requirements and capabilities at run time to furnish best possible service results. Thus we designed and integrated a
video indexing and key framing service within our overall agent-based architecture. We integrated this video indexing and
content-based analysis service to adapt the video content according to run time conditions. We designed a video XML schema
to validate the media content out of this multimedia service according to specific requirements and features, as we will describe
later.
相似文献
Ahmed KarmouchEmail: |