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41.
Mathematical model of vertical electrical sounding by using resistivity method is studied. The model leads to an inverse problem of determination of the unknown leading coefficient (conductivity) of the elliptic equation in R2 in a slab. The direct problem is obtained in the form of mixed BVP in axisymmetric cylindrical coordinates. The additional (available measured) data is given on the upper boundary of the slab, in the form of tangential derivative. Due to ill-conditionedness of the considered inverse problem the logarithmic transformation is applied to the unknown coefficient and the inverse problem is studied as a minimization problem for the cost functional, with respect to the reflection coefficient. The Conjugate Gradient method (CGM) is applied for the numerical solution of this problem. Computational experiments were performed with noise free and random noisy data. 相似文献
42.
Recognizing people by gait promises to be useful for identifying individuals from a distance; in this regard, improved techniques
are under development. In this paper, an improved method for gait recognition is proposed. Binarized silhouette of a motion
object is first represented by four 1-D signals that are the basic image features called the distance vectors. The distance
vectors are differences between the bounding box and silhouette, and extracted using four projections to silhouette. Fourier
Transform is employed as a preprocessing step to achieve translation invariant for the gait patterns accumulated from silhouette
sequences that are extracted from the subjects’ walk in different speed and/or different time. Then, eigenspace transformation
is applied to reduce the dimensionality of the input feature space. Support vector machine (SVM)-based pattern classification
technique is then performed in the lower-dimensional eigenspace for recognition. The input feature space is alternatively
constructed by using two different approaches. The four projections (1-D signals) are independently classified in the first
approach. A fusion task is then applied to produce the final decision. In the second approach, the four projections are concatenated
to have one vector and then pattern classification with one vector is performed in the lower-dimensional eigenspace for recognition.
The experiments are carried out on the most well-known public gait databases: the CMU, the USF, SOTON, and NLPR human gait
databases. To effectively understand the performance of the algorithm, the experiments are executed and presented as increasing
amounts of the gait cycles of each person available during the training procedure. Finally, the performance of the proposed
algorithm is comparatively illustrated to take into consideration the published gait recognition approaches. 相似文献
43.
Mobility path information of cell phone users play a crucial role in a wide range of cell phone applications, including context based search and advertising, early warning systems, city-wide sensing applications such as air pollution exposure estimation and traffic planning. However, there is a disconnect between the low level location data logs available from the cell phones and the high level mobility path information required to support these cell phone applications. In this paper, we present formal definitions to capture the cell phone users’ mobility patterns and profiles, and provide a complete framework, Mobility Profiler, for discovering mobile cell phone user profiles starting from cell based location data. We use real-world cell phone log data (of over 350 K h of coverage) to demonstrate our framework and perform experiments for discovering frequent mobility patterns and profiles. Our analysis of mobility profiles of cell phone users expose a significant long tail in a user’s location-time distribution: A total of 15% of a cell phone user’s time is spent on average in locations that each appears with less than 1% of total time. 相似文献
44.
An assessment of total RMR classification system using unified simulation model based on artificial neural networks 总被引:1,自引:0,他引:1
Engineering design has great importance in the cost and safety of engineering structures. Rock mass rating (RMR) system has
become a reliable and widespread pre-design system for its ease of use and variety in engineering applications such as tunnels,
foundations, and slopes. In RMR system, six parameters are employed in classifying a rock mass: uniaxial compressive strength
of intact rock material (UCS), rock quality designation (RQD), spacing of discontinuities (SD), condition of discontinuities
(CD), condition of groundwater (CG), and orientation of discontinuities (OD). The ratings of the first three parameters UCS,
RQD, and SD are determined via graphic readings where the last three parameters CD, CG, and OD are estimated by the tables
that are composed of interval valued linguistic expressions. Because of these linguistic expresions, the estimated rating
values of the last three become fuzzy especially when the related conditions are close to border of any two classes. In such
cases, these fuzzy situations could lead up incorrect rock class estimations. In this study, an empirical database based on
the linguistic expressions for CD, CG, and OD is developed for training Artificial Neural Network (ANN) classifiers. The results
obtained from graphical readings and ANN classifiers are unified in a simulation model (USM). The data obtained from five
different tunnels, which were excavated for derivation purpose, are used to evaluate classification results of conventional
method and proposed model. Finally, it is noted that more accurate and realistic ratings are reached by means of proposed
model. 相似文献
45.
Detecting and tracking ground targets is crucial in military intelligence in battlefield surveillance. Once targets have been detected, the system used can proceed to track them where tracking can be done using Ground Moving Target Indicator (GMTI) type indicators that can observe objects moving in the area of interest. However, when targets move close to each other in formation as a convoy, then the problem of assigning measurements to targets has to be addressed first, as it is an important step in target tracking. With the increasing computational power, it became possible to use more complex association logic in tracking algorithms. Although its optimal solution can be proved to be an NP hard problem, the multidimensional assignment enjoyed a renewed interest mostly due to Lagrangian relaxation approaches to its solution. Recently, it has been reported that randomized heuristic approaches surpassed the performance of Lagrangian relaxation algorithm especially in dense problems. In this paper, impelled from the success of randomized heuristic methods, we investigate a different stochastic approach, namely, the biologically inspired ant colony optimization to solve the NP hard multidimensional assignment problem for tracking multiple ground targets. 相似文献
46.
In a network, one of the important problems is making an efficient routing decision. Many studies have been carried out on
making a decision and several routing algorithms have been developed. In a network environment, every node has a routing table
and these routing tables are used for making routing decisions. Nowadays, intelligent agents are used to make routing decisions.
Intelligent agents have been inspired by social insects such as ants. One of the intelligent agent types is self a cloning
ant. In this study, a self cloning ant colony approach is used. Self cloning ants are a new synthetic ant type. This ant assesses
the situation and multiplies through cloning or destroying itself. It is done by making a routing decision and finding the
optimal path. This study explains routing table updating by using the self cloning ant colony approach. In a real net, this
approach has been used and routing tables have been created and updated for every node. 相似文献
47.
Elif Derya Übeyli 《Expert systems with applications》2009,36(5):9031-9038
This paper describes the application of adaptive neuro-fuzzy inference system (ANFIS) model for automatic detection of electroencephalographic changes. Decision making was performed in two stages: feature extraction by computation of Lyapunov exponents and classification by the ANFIS trained with the backpropagation gradient descent method in combination with the least squares method. Five types of electroencephalogram (EEG) signals were classified by five ANFIS classifiers. To improve diagnostic accuracy, the sixth ANFIS classifier (combining ANFIS) was trained using the outputs of the five ANFIS classifiers as input data. The proposed ANFIS model combined the neural network adaptive capabilities and the fuzzy logic qualitative approach. Some conclusions concerning the saliency of features on classification of the EEG signals were obtained through analysis of the ANFIS. The performance of the ANFIS model was evaluated in terms of training performance and classification accuracies and the results confirmed that the proposed ANFIS model has potential in classifying the EEG signals. 相似文献
48.
Anthony?Etuk Timothy?J.?Norman Murat??ensoyEmail author Mudhakar?Srivatsa 《Autonomous Agents and Multi-Agent Systems》2017,31(3):531-560
The presence of numerous and disparate information sources available to support decision-making calls for efficient methods of harnessing their potential. Information sources may be unreliable, and misleading reports can affect decisions. Existing trust and reputation mechanisms typically rely on reports from as many sources as possible to mitigate the influence of misleading reports on decisions. In the real world, however, it is often the case that querying information sources can be costly in terms of energy, bandwidth, delay overheads, and other constraints. We present a model of source selection and fusion in resource-constrained environments, where there is uncertainty regarding the trustworthiness of sources. We exploit diversity among sources to stratify them into homogeneous subgroups to both minimise redundant sampling and mitigate the effect of certain biases. Through controlled experiments, we demonstrate that a diversity-based approach is robust to biases introduced due to dependencies among source reports, performs significantly better than existing approaches when sampling budget is limited and equally as good with an unlimited budget. 相似文献
49.
Murat Arcak Author vitae 《Automatica》2011,(6):1219-1229
We present a condition that guarantees spatial uniformity for the asymptotic behavior of the solutions of a reaction–diffusion PDE with Neumann boundary conditions. This condition makes use of the Jacobian matrix of the reaction terms and the second Neumann eigenvalue of the Laplacian operator on the given spatial domain, and eliminates the global Lipschitz assumptions commonly used in mathematical biology literature. We then derive numerical procedures that employ linear matrix inequalities to certify this condition, and illustrate these procedures on models of several biochemical reaction networks. Finally, we present an analog of this PDE result for the synchronization of a network of identical ODE models coupled by diffusion terms. From a systems biology perspective, the main contribution of the paper is to blend analytical and numerical tools from nonlinear systems and control theory to derive a relaxed and verifiable condition for spatial uniformity of biological processes. 相似文献
50.
We extend the traditional notion of passivity to a forced system whose equilibrium is dependent on the control input by defining equilibrium-independent passivity, a system property characterized by a dissipation inequality centered at an arbitrary equilibrium point. We provide a necessary input/output condition which can be tested for systems of arbitrary dimension and sufficient conditions to certify this property for scalar systems. An example from network stability analysis is presented which demonstrates the utility of this new definition. We then proceed to numerical certification of equilibrium-independent passivity using sum-of-squares programming. Finally, through numerical examples we show that equilibrium-independent passivity is less restrictive than incremental passivity. 相似文献