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排序方式: 共有2777条查询结果,搜索用时 15 毫秒
51.
52.
Guillaume F. Remy Hassan B. Kazemian Phil Picton 《Neural computing & applications》2011,20(6):879-887
This paper is to introduce an application of Computational Intelligence (CI) to Moving Picture Expert Group-4 (MPEG-4) video
compression over IEEE.802.15.1 wireless communication, known as Bluetooth 1.2, in order to improve picture quality. The 2.4 GHz
Industrial, Scientific and Medical frequency band is used for the IEEE.802.15.1 standard. IEEE.802.15.1 can be affected by
noise and interference due to other neighboring wireless devices sharing the same frequency carrier. The noise and interference
create difficulties in ascertaining an accurate real-time transmission rate at the receiving end. Furthermore, the MPEG-4
codec is an object-oriented compression system and demands a high bandwidth. It is therefore difficult to avoid excessive
delay, image quality degradation and/or data loss during MPEG-4 video transmission over standard systems. A new buffer entitled
‘buffer added’ has been introduced at the input of the Bluetooth 1.2 device. This buffer is controlled by a Rule-Based Fuzzy
(RBF) logic controller at the input and a neural-fuzzy controller (NFC) at the output. The two new fuzzy rules manipulate
and supervise the flow of video over the Bluetooth 1.2 standard. The computer simulation results illustrate the comparison
between a non-CI video transmission over Bluetooth 1.2 and the proposed design, confirming that the applications of RBF and
NFC do improve the image quality, reduce data loss and reduce time delay. 相似文献
53.
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
54.
55.
Isa Ebtehaj Hossein Bonakdari Shahaboddin Shamshirband 《Engineering with Computers》2016,32(4):691-704
The minimum velocity required to prevent sediment deposition in open channels is examined in this study. The parameters affecting transport are first determined and then categorized into different dimensionless groups, including “movement,” “transport,” “sediment,” “transport mode,” and “flow resistance.” Six different models are presented to identify the effect of each of these parameters. The feed-forward neural network (FFNN) is used to predict the densimetric Froude number (Fr) and the extreme learning machine (ELM) algorithm is utilized to train it. The results of this algorithm are compared with back propagation (BP), genetic programming (GP) and existing sediment transport equations. The results indicate that FFNN-ELM produced better results than FNN-BP, GP and existing sediment transport methods in both training (RMSE = 0.26 and MARE = 0.052) and testing (RMSE = 0.121 and MARE = 0.023). Moreover, the performance of FFNN-ELM is examined for different pipe diameters. 相似文献
56.
This paper presents sliding mode control and model reference adaptive control strategies for the tape transport mechanism. A nonlinear multivariable MIMO model of the process, consisting of take-up and supply reel servos for tape tension control and capstan servo for speed control is considered. The sliding mode control is applied for the nonlinear dynamic model of the process, while the model reference adaptive control deals with the linearized one. Moreover, in order to associate with the realistic model of system, design of controllers is accomplished with respect to parametric uncertainties. It is shown that both control strategies can guarantee asymptotic stability of the closed-loop system and tracking of desired outputs with the appropriate pace in the presence of uncertainties. Finally, simulation results demonstrate the effectiveness of the proposed controllers. 相似文献
57.
This paper presents a new multi-stage genetic programming (MSGP) strategy for modeling nonlinear systems. The proposed strategy is based on incorporating the individual effect of predictor variables and the interactions among them to provide more accurate simulations. According to the MSGP strategy, an efficient formulation for a problem comprises different terms. In the first stage of the MSGP-based analysis, the output variable is formulated in terms of an influencing variable. Thereafter, the error between the actual and the predicted value is formulated in terms of a new variable. Finally, the interaction term is derived by formulating the difference between the actual values and the values predicted by the individually developed terms. The capabilities of MSGP are illustrated by applying it to the formulation of different complex engineering problems. The problems analyzed herein include the following: (i) simulation of pH neutralization process, (ii) prediction of surface roughness in end milling, and (iii) classification of soil liquefaction conditions. The validity of the proposed strategy is confirmed by applying the derived models to the parts of the experimental results that were not included in the analyses. Further, the external validation of the models is verified using several statistical criteria recommended by other researchers. The MSGP-based solutions are capable of effectively simulating the nonlinear behavior of the investigated systems. The results of MSGP are found to be more accurate than those of standard GP and artificial neural network-based models. 相似文献
58.
Network-on-chip-based multiprocessor systems-on-chip are considered as future embedded systems platforms. One of the steps in mapping an application onto such a parallel platform involves scheduling the communication on the network-on-chip. This paper presents different scheduling strategies that minimize resource usage by exploiting all scheduling freedom offered by networks-on-chip. It also introduces a technique to take the dynamism in applications into account when scheduling the communication of an application on the network-on-chip while minimizing the resource usage. Our experiments show that resource-utilization is improved when compared to existing techniques. 相似文献
59.
Alireza Rahimi-Vahed Ali Hossein Mirzaei 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2008,12(5):435-452
Flow shop problems as a typical manufacturing challenge have gained wide attention in academic fields. In this paper, we consider
a bi-criteria permutation flow shop scheduling problem, where the weighted mean completion time and the weighted mean tardiness
are to be minimized simultaneously. Due to the complexity of the problem, it is very difficult to obtain optimum solution
for this kind of problems by means of traditional approaches. Therefore, a new multi-objective shuffled frog-leaping algorithm
(MOSFLA) is introduced for the first time to search locally Pareto-optimal frontier for the given problem. To prove the efficiency
of the proposed algorithm, various test problems are solved and the reliability of the proposed algorithm, based on some comparison
metrics, is compared with three distinguished multi-objective genetic algorithms, i.e. PS-NC GA, NSGA-II, and SPEA-II. The
computational results show that the proposed MOSFLA performs better than the above genetic algorithms, especially for the
large-sized problems. 相似文献
60.
Hydrological Drought Assessment in Northwestern Iran Based on Streamflow Drought Index (SDI) 总被引:7,自引:3,他引:4
Hossein Tabari Jaefar Nikbakht P. Hosseinzadeh Talaee 《Water Resources Management》2013,27(1):137-151
Drought is a natural and worldwide phenomenon that occurs when water availability is significantly below normal levels during a significant period of time and cannot meet demand. This work focused on the hydrologic drought defined by the streamflow drought index (SDI) for overlapping periods of 3, 6, 9 and 12 months at 14 hydrometric stations in the northwest of Iran over the period 1975–2009. It was found that some of the streamflow volume series did not follow the normal distribution. The ability of the log-normal, exponential and uniform probability distributions was examined in order to choose the most suitable distribution, and the log-normal distribution was used to fit the long-term streamflow data. The results of the hydrological drought analysis based on the SDI showed that almost all the stations suffered from extreme droughts during the study period. Additionally, extreme droughts occurred most frequently in the last 12 years from 1997–1998 to 2008–2009. 相似文献