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1.
This paper describes an online lossless data-compression method using adaptive arithmetic coding. To achieve good compression efficiency, we employ an adaptive fuzzy-tuning modeler that applies fuzzy inference to deal efficiently with the problem of conditional probability estimation. In comparison with other lossless coding schemes, the compression results of the proposed method are good and satisfactory for various types of source data, Since we adopt the table-lookup approach for the fuzzy-tuning modeler, the design is simple, fast, and suitable for VLSI implementation  相似文献   

2.
This paper details the Particle Swarm Optimization (PSO) technique for the optimal design of analog circuits. It is shown the practical suitability of PSO to solve both mono-objective and multiobjective discrete optimization problems. Two application examples are presented: maximizing the voltage gain of a low noise amplifier for the UMTS standard and computing the Pareto front of a bi-objective problem, maximizing the high current cut off frequency and minimizing the parasitic input resistance of a second generation current conveyor. The aptness of PSO to optimize difficult circuit problems, in terms of numbers of parameters and constraints, is shown.  相似文献   

3.
For today’s wireless mobile communication systems, efficient use of limited radio spectrum with minimum interferences is required. Itinvestigates an Optimal Genetic Algorithm approach (GA) for Hybrid Channel allocation (NP hard) focusing on reduction in interference in cellular Network. Obtained an interference graph based fitness function to enhance the performance of HCA for interference reduction. It is shown that the use of integer genetic representation for Crossover and mutation operation enhances the speed of GA leading to less computation time. Comparison of proposed method is done with reported literature for KUNZ 4 which results in less co-channel and co-site interference depicted by interfering edges and also number of generations required are less. The result for KUNZ 1, KUNZ 2 and KUNZ 3 are obtained with minimum interference along with computation time.  相似文献   

4.
In this paper, we propose a new method for kernel optimization in kernel-based dimensionality reduction techniques such as kernel principal component analysis and kernel discriminant analysis. The main idea is to use the graph embedding framework for these techniques and, therefore, by formulating a new minimization problem to simultaneously optimize the kernel parameters and the projection vectors of the chosen dimensionality reduction method. Experimental results are conducted in various datasets, varying from real-world publicly available databases for classification benchmarking to facial expressions and face recognition databases. Our proposed method outperforms other competing ones in classification performance. Moreover, our method provides a systematic way to deal with kernel parameters whose calculation was treated rather superficially so far and/or experimentally, in most of the cases.  相似文献   

5.
A fast and efficient hybrid fractal-wavelet image coder.   总被引:1,自引:0,他引:1  
The excellent visual quality and compression rate of fractal image coding have limited applications due to exhaustive inherent encoding time. This paper presents a new fast and efficient image coder that applies the speed of the wavelet transform to the image quality of the fractal compression. Fast fractal encoding using Fisher's domain classification is applied to the lowpass subband of wavelet transformed image and a modified set partitioning in hierarchical trees (SPIHT) coding, on the remaining coefficients. Furthermore, image details and wavelet progressive transmission characteristics are maintained, no blocking effects from fractal techniques are introduced, and the encoding fidelity problem common in fractal-wavelet hybrid coders is solved. The proposed scheme promotes an average of 94% reduction in encoding-decoding time comparing to the pure accelerated Fractal coding results. The simulations also compare the results to the SPIHT wavelet coding. In both cases, the new scheme improves the subjective quality of pictures for high-medium-low bitrates.  相似文献   

6.
粒子群优化算法(PSO)自提出以来,已经被广泛地应用于求解各类复杂的优化问题,过去对粒子群算法的研究主要集中在融入新的优化方法或对其相关参数进行调整,但这样只会使得PSO更加复杂.针对这一问题,文中提出一种改进的混沌粒子群优化算法(ICPSO),ICPSO从粒子群优化算法的时间与寻优实时角度出发(即在较短的时间内获得较好的解),对粒子速度更新算子进行了简化,每隔一定代数后,在最优解邻近区域引入混沌扰动以避免种群陷入局部最优解.数值实验结果表明:提出的算法相对于文献给出的PSO改进算法,不仅能够获得较好的最优解,而且还具有较快的收敛速度和较好的稳定性.  相似文献   

7.
We present a fast wavelet-based time-domain modeling technique to study the effect of electromagnetic (EM)-wave propagation on the performance of high-power and high-frequency multifinger transistors. The proposed approach solves the active device model that combines the transport physics, and Maxwell's equations on nonuniform self-adaptive grids, obtained by applying wavelet transforms followed by hard thresholding. This allows forming fine and coarse grids in the locations where variable solutions change rapidly and slowly, respectively. A CPU time reduction of 75% is achieved compared to a uniform-grid case, while maintaining the same degree of accuracy. After validation, the potential of the developed technique is demonstrated by EM-physical modeling of multifinger transistors. Different numerical examples are presented, showing that accurate modeling of high-frequency devices should incorporate the effect of EM-wave propagation and electron-wave interactions within and around the device. Moreover, high-frequency advantages of multifinger transistors over single-finger transistors are underlined through numerical examples. To our knowledge, this is the first time in the literature a fully numerical EM-physics-based simulator for accurate modeling of high-frequency multifinger transistors is introduced and implemented.  相似文献   

8.
This paper presents a simple heuristic technique to arrive at the optimal redundancy allocation. There is a drastic reduction in the number of steps because of the criterion evolved, which allows for the addition of one or more units, simultaneously, at more than one stage. Examples have been provided to demonstrate the effectiveness of the technique.  相似文献   

9.
It is shown that cubic-spline interpolation (CSI) can be performed by a fast and efficient computation for the encoding and decoding processes of image coding. It requires substantially fewer additions and multiplications than the original CSI algorithm. Furthermore, a new type of overlap-save scheme is utilized to solve the boundary-condition problems that occur between two neighboring subimages in the actual image. It is also shown that a very efficient nine-point Winograd discrete Fourier transform (WDFT) can be used to replace the fast Fourier transform (FFT) needed to implement the CSI scheme in the modified JPEG encoder. Finally, the proposed fast new CSI algorithm with a compression ratio of 9:1 is used along with the JPEG standard to speed up the modified JPEG encoder-decoder and still obtain a better quality of reconstructed image for higher compression ratios  相似文献   

10.
A multi-input Muller C-element has frequently been used for joining signal transitions or completion time detection in self-timed circuits. An n-input Muller C-element design which uses the multilevel logic design technique and has a symmetric format for any integer n ⩾2 is presented. In comparison with series-parallel MOS structure implementations and C-element tree implementations, the present design has fewer restrictions in terms of n, less path delay, less delay variance from inputs to output, and less area consumption. Experimental validation based on an industrial standard cell library is presented  相似文献   

11.
The two protection methods wrapping and steering used in IEEE 802.17 resilient packet ring (RPR) provide fast but very inefficient and limited network failure recovery. Due to the increased length of the backup path, RPR suffers from high traffic loss, a decreased throughput-delay performance, and the lack of resilience against multiple link and/or node failures. To achieve an improved resilience, interconnecting a subset of the ring nodes by means of a dark-fiber single-hop star wavelength division multiplexing (WDM) network is proposed. In doing so, the ring network is divided into separate domains, each being fully recoverable from a single link or node failure without losing full network connectivity. A novel hybrid fault recovery technique, termed protectoration, is proposed and examined by means of probabilistic analysis and simulation in terms of stability, channel utilization, and throughput-delay performance. The proposed protectoration technique 1) combines the fast recovery time of protection and the bandwidth efficiency of restoration, 2) provides full recovery from multiple link and node failures, 3) builds on both wrapping and steering protection methods of RPR and, thus, allows for an evolutionary upgrade of existing RPR networks, and 4) does not require the convergence of routing protocols in response to failures and, thus, improves the routing stability and network availability. Numerical investigations in this paper show that the location of failures has a strong impact on the network performance. For a given failure location, the protectoration technique is able to accommodate multiple ring failures without significant performance loss.  相似文献   

12.
A technique is presented which measures the number of fast states (/cm2) between (flat band) φs = 0 and φs = 2φB using a high frequency C ? V and d.c. ramp I ? V tracing of any MIS capacitor. For cases where fast state densities near flat band are insignificant, the true flat band point V(φs = 0) is obtained from the high frequency C ? V curve. Then from the (I ? V) curve the V(φs = 2φB) point is obtained by graphically measuring off an area = Imax (2kT/q) ln (NB/ni) between V = VFB, V = V1, I = Imax, and I ? V curve. Then the fast state density (NFS(/cm2)), is obtained from the expression: s = 2φB ? Vφs = 0 = 2φB + qCins[Nsi + NFS] where all values are known. For cases where significant fast states exist near flat band, the true flat band point can be obtained graphically from the I ? V tracing using any value of surface potential near mid gap calculated from the high frequency capacitance.  相似文献   

13.
The authors present a very efficient minimum mean-squared error (MMSE) encoding method useful for vector quantization. Using this method results in a considerable reduction in the number of multiplications and additions. The increase in the number of comparisons is moderate, and therefore the overall saving in the number of operations is still considerable. Very little precomputation and extra storage is required  相似文献   

14.
With aggressive scaling of CMOS technology, it is essential to consider chip temperature in all design levels of digital systems to improve chip reliability and leakage power consumption. In this paper, we present a two phase fixed-outline floorplanning framework that attempts to reduce the peak-temperature of the chip. The first phase distributes evenly the available dead space between the floorplan blocks of a chip, so as to reduce the peak-temperature. The second phase employs a two-stage convex optimization formulation to perform fixed-outline floorplanning such that minimizes the peak-temperature while satisfying physical constraints. To mitigate the time and computational complexity of capturing the temperature behavior, we present a less computational expensive analogous formulation that approximates the temperature of a block by its corresponding power density. Although, the corresponding power density formulation exhibits lower complexity the experimental results demonstrate its high degree of accuracy. Moreover, this formulation manages to achieve significant improvements in terms of peak-temperature and runtime for almost all of the test cases. We investigate the trade-off between peak-temperature and area as well and provide conditions that result in a reasonable reduction of peak-temperature with minimum increase of the dead space.  相似文献   

15.
We propose a fast and efficient image retrieval system based on color and texture features. The color features are represented by color histograms and texture features are represented by block difference of inverse probabilities (BDIP) and block variation of local correlation coefficients (BVLC). It is observed that color features in combination with the texture features derived on the brightness component provides approximately similar results when color features are combined with the texture features using all three components of color, but with much less processing time. An analysis of various distance measures reveals that the square-chord distance measure outperforms the other prominent distance measures for the proposed method. Detailed experimental analysis is carried out using precision and recall on four datasets: Corel-5K, Corel-10K, UKbench and Holidays. The time analysis is also performed to compare processing speeds of the proposed method with the existing similar best methods.  相似文献   

16.
随着移动互联网的发展和4G网络的成熟,移动视频业务已逐步成为主流业务,移动视频已成为互联网企业抢占的制高点,运营商在其中如何定位需要深入思考。本研究首先立足网络本身,在4G环境下研究视频感知监测、缓存、动态转码等一系列技术手段,建立视频质量优化与保障体系。在此基础上,探索构建3GPP标准的AAC架构,结合PCC功能,通过标准接口将网络QoS能力向互联网公司开放,参与视频的业务调度过程,进而具备分享业务价值链的能力。  相似文献   

17.
A new fuzzy logic and histogram based algorithm for enhancing low contrast color images has been proposed here. The method is computationally fast compared to conventional and other advanced enhancement techniques. It is based on two important parameters M and K, where M is the average intensity value of the image, calculated from the histogram and K is the contrast intensification parameter. The given RGB image is converted into HSV color space to preserve the chromatic information contained in the original image. To enhance the image, only the V component is stretched under the control of the parameters M and K. The proposed method has been compared with conventional contrast enhancement techniques as well as with advanced algorithms. All the above techniques were based on the principle of transforming the skewed histogram of the original image into a uniform histogram. The performance of the different contrast enhancement algorithms are evaluated based on the visual quality, Tenengrad, CII and the computational time. The inter comparison of different techniques was carried out on different low contrast color images. Based on the performance analysis, we advocate that our proposed Fuzzy Logic method is well suited for contrast enhancement of low contrast color images.  相似文献   

18.
We propose a quality-driven cross-layer optimization scheme for wireless direct sequence code division multiple access (DS-CDMA) visual sensor networks (VSNs). The scheme takes into account the fact that different nodes image videos with varying amounts of motion and determines the source coding rate, channel coding rate, and power level for each node under constraints on the available bit rate and power. The objective is to maximize the quality of the video received by the centralized control unit (CCU) from each node. However, since increasing the power level of one node will lead to increased interference with the rest of the nodes, simultaneous maximization of the video qualities of all nodes is not possible. In fact, there are an infinite number of Pareto-optimal solutions. Thus, we propose the use of the Nash bargaining solution (NBS), which pinpoints one of the infinite Pareto-optimal solutions, based on the stipulation that the solution should satisfy four fairness axioms. The NBS results in a mixed-integer optimization problem, which is solved using the particle swarm optimization (PSO) algorithm. The presented experimental results demonstrate the advantages of the NBS compared with alternative optimization criteria.  相似文献   

19.
This paper presents an efficient ear recognition technique which derives benefits from the local features of the ear and attempt to handle the problems due to pose, poor contrast, change in illumination and lack of registration. It uses (1) three image enhancement techniques in parallel to neutralize the effect of poor contrast, noise and illumination, (2) a local feature extraction technique (SURF) on enhanced images to minimize the effect of pose variations and poor image registration. SURF feature extraction is carried out on enhanced images to obtain three sets of local features, one for each enhanced image. Three nearest neighbor classifiers are trained on these three sets of features. Matching scores generated by all three classifiers are fused for final decision. The technique has been evaluated on two public databases, namely IIT Kanpur ear database and University of Notre Dame ear database (Collections E). Experimental results confirm that the use of proposed fusion significantly improves the recognition accuracy.  相似文献   

20.
A fast adaptive frequency calibration (AFC) technique with self-calibration for fast-locking phase-locked loops is presented with frequency-selecting switches. The proposed AFC directly calculates the proper switch states of the voltage-controlled oscillator (VCO). It requires only six clock cycles of the reference oscillator regardless of the number of VCO switches to reach the final switch state in the ideal case. The proposed method counts the number of VCO cycles per reference clock period for the minimum VCO frequency (MIN) and the maximum VCO frequency (MAX) during the first four-clock periods. For the following two-clock periods, the proper states of the VCO switches are set to the calculated value from MIN, MAX and the desired division ratio for a target frequency (EST). A frequency synthesiser with the proposed AFC was implemented on a 0.18?µm CMOS process. The AFC time decreased from 40 to 0.4?µs employing the proposed scheme such that the total lock time is 40?µs with the loop bandwidth of 40?kHz.  相似文献   

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