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排序方式: 共有858条查询结果,搜索用时 31 毫秒
21.
22.
Pandian Vasant Nader Barsoum 《Engineering Applications of Artificial Intelligence》2009,22(4-5):767-777
Many engineering, science, information technology and management optimization problems can be considered as non-linear programming real-world problems where all or some of the parameters and variables involved are uncertain in nature. These can only be quantified using intelligent computational techniques such as evolutionary computation and fuzzy logic. The main objective of this research paper is to solve non-linear fuzzy optimization problem where the technological coefficient in the constraints involved are fuzzy numbers, which was represented by logistic membership functions using the hybrid evolutionary optimization approach. To explore the applicability of the present study, a numerical example is considered to determine the production planning for the decision variables and profit of the company. 相似文献
23.
The assumption of proportional hazards (PH) fundamental to the Cox PH model sometimes may not hold in practice. In this paper, we propose a generalization of the Cox PH model in terms of the cumulative hazard function taking a form similar to the Cox PH model, with the extension that the baseline cumulative hazard function is raised to a power function. Our model allows for interaction between covariates and the baseline hazard and it also includes, for the two sample problem, the case of two Weibull distributions and two extreme value distributions differing in both scale and shape parameters. The partial likelihood approach can not be applied here to estimate the model parameters. We use the full likelihood approach via a cubic B-spline approximation for the baseline hazard to estimate the model parameters. A semi-automatic procedure for knot selection based on Akaike’s information criterion is developed. We illustrate the applicability of our approach using real-life data. 相似文献
24.
Sobhani AM Amini SR Tyndall JD Azizi E Daneshtalab M Khalaj A 《Journal of molecular graphics & modelling》2006,25(4):459-469
Azolylalkylquinolines (AAQs) are a family of quinolines with varying degrees of cytotoxic activity (comparable or moderately superior to adriamycin in some cases) developed in the past decade in our group where their exact mode of action is still unclear. In this study the most probable DNA binding mode of AAQs was investigated employing a novel flexible ligand docking approach by using AutoDock 3.0. Forty-nine AAQs with known experimental inhibitory activity were docked onto d(CGCAAATTTGCG)(2), d(CGATCG)(2) and d(CGCG)(2) oligonucleotides retrieved from the Protein Data Bank (PDB IDs: 102D, 1D12 and 1D32, respectively) as the representatives of the three plausible models of interactions between chemotherapeutic agents and DNA (groove binding, groove binding plus intercalation and bisintercalation, respectively). Good correlation (r(2)=0.64) between calculated binding energies and experimental inhibitory activities was obtained using groove binding plus intercalation model for phenyl-azolylalkylquinoline (PAAQ) series. Our findings show that the most probable mode of action of PAAQs as DNA binding agents is via intercalation of quinolinic moiety between CG base pairs with linker chain and azole moiety binding to the minor groove. 相似文献
25.
The contribution of this paper is three empirical evaluations of a reference model for the practice of software reuse. Our
research thesis is that software development based upon a software reuse reference model improves quality of products, productivity
of processes and product time‐to‐market for many software development enterprises. The definition and investigation of such
a model has been carried out using three steps. First, the reference model is developed based on existing software reuse concepts.
Second, this reference model is empirically evaluated using three studies: one using a survey method, one using a case studies
method, and one using a legacy studies method. Third, the impact of the reference model on software development productivity,
quality, and time‐to‐market is empirically derived.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
26.
The authors examined the effect of learning on multiple encounters with sources of social ambiguity in individuals with generalized social phobia (GSP). The authors modified G. B. Simpson and H. Kang's (1994) paradigm and presented prime-target word pairs to individuals with GSP and nonanxious controls (NACs) to prime threat and nonthreat meanings of homographs and examine the effect of this priming on later encounters with that homograph. Consistent with previous research, NACs showed faster response latencies naming a target primed by a homograph with the same meaning activated in two successive trials than naming the same target primed by an unrelated word. Furthermore, NACs showed slower response latencies naming a target when a different meaning of the homograph prime was activated in successive trials than naming a target primed by an unrelated word. GSP participants did not show this pattern in learning a nonthreat meaning of a homograph. These results support the hypothesis that a faulty learning mechanism may be involved in social anxiety. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
27.
Two nonlinear control techniques are proposed for an atomic force microscope system. Initially, a learning-based control algorithm is developed for the microcantilever-sample system that achieves asymptotic cantilever tip tracking for periodic trajectories. Specifically, the control approach utilizes a learning-based feedforward term to compensate for periodic dynamics and high-gain terms to account for non-periodic dynamics. An adaptive control algorithm is then developed to achieve asymptotic cantilever tip tracking for bounded tip trajectories despite uncertainty throughout the system parameters. Simulation results are provided to illttstrate the efficacy and performance of the control strategies. 相似文献
28.
In this contribution, we discuss the possibility of applying the scattering-cancellation-based plasmonic cloaking technique to reduce the scattering from a sensing device, lowering its disturbance on sensing without affecting its ability to measure and “sense” the external world. The plasmonic cloak, while allowing the external fields to penetrate into the cover, may be able to suppress the scattering without necessarily shielding its interiors from the impinging light, which may be of great use if we wish to “sense” the external world, or receive an external signal, from inside the cloak. Our results may provide a unique sensing system that may receive and transmit signals, while its presence may not be perceived by the surrounding. This may be of great importance in a wide range of biological, optical, physical and engineering applications. 相似文献
29.
Enhancement of immune response in mice fed with Streptococcus thermophilus and Lactobacillus acidophilus 总被引:1,自引:0,他引:1
G Perdigon M E Nader de Macias S Alvarez G Oliver A A Pesce de Ruiz Holgado 《Journal of dairy science》1987,70(5):919-926
Swiss mice, fed for 8 consecutive d with 50 micrograms/d of viable cultures of Lactobacillus acidophilus and Streptococcus thermophilus, showed significant variation in their immune system. In order to study this phenomenon assays for macrophage and lymphocyte function were carried out. Both lactic acid bacteria enhanced significantly the enzymatic and phagocytic activity of peritoneal macrophages as checked against the controls and also accelerated the phagocytic function of the reticuloendothelial system as revealed by the carbon clearance test. On the 2nd d (100 micrograms), L. acidophilus reached a peak of K = .271, which remained high. Streptococcus thermophilus was effective only on the 2nd d and then decreased. The lymphocytic activity studied by immunoglobulin secreting cells was assayed by Jerne's method of plaque-forming cells (PFC). This activity also was increased by the two microorganisms. Streptococcus thermophilus proved more effective than L. acidophilus. Lactobacillus acidophilus and S. thermophilus activated macrophages and lymphocytes and produced the same increase in the immune response of mice whether administered orally or intraperitoneally. 相似文献
30.
Hadi Kalani Alireza Akbarzadeh S. Nader Nabavi Sahar Moghimi 《Intelligent Service Robotics》2018,11(2):187-205
Human mastication is a complex and rhythmic biomechanical process which is regulated by a brain stem central pattern generator (CPG). Masticatory patterns, frequency and amplitude of mastication are different from person to person and significantly depend on food properties. The central nervous system controls the activity of muscles to produce smooth transitions between different movements. Therefore, to rehab human mandibular system, there is a real need to use the concept of CPG for development of a new methodology in jaw exercises and to help jaw movements recovery. This paper proposes a novel method for real-time trajectory generation of a mastication rehab robot. The proposed method combines several methods and concepts including kinematics, dynamics, trajectory generation and CPG. The purpose of this article is to provide a methodology to enable physiotherapists to perform the human jaw rehabilitation. In this paper, the robotic setup includes two Gough–Stewart platforms. The first platform is used as the rehab robot, while the second one is used to model the human jaw system. Once the modeling is completed, the second robot will be replaced by an actual patient for the selected physiotherapy. Gibbs–Appell’s formulation is used to obtain the dynamics equations of the rehab robot. Then, a method based on the Fourier series is employed to tune parameters of the CPG. It is shown that changes in leg lengths, due to the online changes of the mastication parameters, occur in a smooth and continuous manner. The key feature of the proposed method, when applied to human mastication, is its ability to adapt to the environment and change the chewing pattern in real-time parameters, such as amplitudes as well as jaw movements velocity during mastication. 相似文献