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Search Results: 1 - 10 of 1443 matches for " optimizing wire configuration "
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Investigating the effect of modifying the EEG cap lead configuration on the gradient artifact in simultaneous EEG-fMRI
Karen J. Mullinger,Muhammad E. H. Chowdhury
Frontiers in Neuroscience , 2014, DOI: 10.3389/fnins.2014.00226
Abstract: EEG data recorded during simultaneous fMRI are contaminated by large voltages generated by time-varying magnetic field gradients. Correction of the resulting gradient artifact (GA) generally involves low-pass filtering to attenuate the high-frequency voltage fluctuations of the GA, followed by subtraction of a GA template produced by averaging over repeats of the artifact waveforms. This average artifact subtraction (AAS) process relies on the EEG amplifier having a large enough dynamic range to characterize the artifact voltages and on invariance of the artifact waveform over repeated image acquisitions. Saturation of the amplifiers and changes in subject position can leave unwanted residual GA after AAS. Previous modeling work suggested that modifying the lead layout and the exit position of the cable bundle on the EEG cap could reduce the GA amplitude. Here, we used simulations and experiments to evaluate the effect of modifying the lead paths on the magnitude of the GA and on the residual artifact after AAS. The modeling work showed that for wire paths following great circles, the smallest overall GA occurs when the leads converge at electrode Cz. The performance of this new cap design was compared with a standard cap in experiments on a spherical agar phantom and human subjects. Using gradient pulses applied separately along the three Cartesian axes, we found that the GA due to the foot-head gradient was most significantly reduced relative to a standard cap for the phantom, whereas the anterior-posterior GA was most attenuated for human subjects. In addition, there was an overall 37% reduction in the RMS GA amplitude produced by a standard EPI sequence when comparing the two caps on the phantom. In contrast, the subjects showed an 11% increase in the average RMS of the GA. This work shows that the optimal design reduces the GA on a spherical phantom however; these gains are not translated to human subjects, probably due to the differences in geometry.
SM-PSO Algorithm-Based Configuration Optimal Design of Distributed SAR Satellite System

Zhang Jin-xiu,Wang Ji-he,Cao Xi-bin,Lan Sheng-chang,

电子与信息学报 , 2008,
Abstract: Aimed at the distributed SAR satellite system consisting of more than three satellites, SM-PSO algorithm-based configuration optimal design is proposed in this paper. The mean orbital elements differences of among satellites are given and the normal configuration design flow of distributed SAR satellite system is presented. In order to realize exactly and fleetly system configuration design faced to mission requirements, the SM-PSO algorithm-based configuration optimal design method is developed. The configuration optimal design is completed in terms of configuration stability, limited by effective baseline range, working time and ground coverage area. It is indicated that the system configuration initial parameters from this method can meet with ground converge and relative steady effective baseline requirements.
Hydrogenation of Polycrystalline SiGe Thin Films by Hot Wire Technique

Zhang Jianjun,Hu Zengxin,Gu Shibin,Zhao Ying,Geng Xinhua,

半导体学报 , 2007,
Abstract: An optimized condition for defect passivation by the hot-wire technique was established.Effects of hydrogenation for polycrystalline SiGe (poly-Si1-xGex) thin films were estimated by investigating the dark conductivity and activation energy that derive from the conductivity as a function of the temperature.The results show that this technique can effectively reduce defects present in poly-Si1-xGex films.By optimizing the substrate and filament temperatures,the treatment can be accomplished in a short time of 20~30min,which is considerably shorter than other hydrogenation techniques.
Studies of implosion processes of nested tungsten wire-array Z-pinch

Ning Cheng,Ding Ning,Liu Quan,Yang Zhen-Hua,
宁 成
,丁 宁,刘 全,杨震华

物理学报 , 2006,
Abstract: Nested wire-array is a kind of promising structured-load because it can improve the quality of Z-pinch plasma and enhance the radiation power of X-ray source. Based on the zero-dimensional model, the assumption of wire-array collision, and the criterion of optimized load (maximal load kinetic energy), optimization of the typical nested wire-array as a load of Z machine at Sandia Laboratory was carried out. It was shown that the load has been basically optimized. The Z-pinch process of the typical load was numerically studied by means of one-dimensional three-temperature radiation magneto-hydrodynamics (RMHD) code. The obtained results reproduce the dynamic process of the Z-pinch and show the implosion trajectory of nested wire-array and the transfer process of drive current between the inner and outer array. The experimental and computational X-ray pulse was compared, and it was suggested that the assumption of wire-array collision was reasonable in nested wire-array Z-pinch at least for the current level of Z machine.
Computation of the Strand Resistance Using the Core Wire Strain Measurement  [PDF]
Keunhee Cho, Sung Tae Kim, Sung Yong Park, Young-Hwan Park
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.511103

This paper proposes a method enabling to compute the prestressing strand resistance using the strain measured on only one core wire. Numerical analysis is conducted considering the pitch length of the strand and the diameters of the core wire and helical wires as parameters. The results verify that the relation between the stresses of the core wire and helical wires can be expressed in terms of the helical angle. Based on this observation, a formula computing directly the prestress force in the strand from the strain measured in the core wire is suggested. Owing to the recently developed measurement method for the core wire strain, the proposed formula can be exploited to determine the prestress of the strand.

Optimal operation of Petlyuk distillation: Steady-state behavior
Ivar J. Halvorsen,Sigurd Skogestad
Modeling, Identification and Control , 2001, DOI: 10.4173/mic.2001.3.3
Abstract: The "Petlyuk" or "dividing-wall" or "fully thermally coupled" distillation column is an interesting alternative to the conventional cascaded binary columns for separation of multi-component mixtures. However, the industrial use has been limited, and difficulties in operation have been reported as one reason. With three product compositions controlled, the system has two degrees of freedom left for on-line optimization. We show that the steady-state optimal solution surface is quite narrow, and depends strongly on disturbances and design parameters. Thus it seems difficult to achieve the potential energy savings compared to conventional approaches without a good control strategy. We discuss candidate variables which may be used as feedback variables in order to keep the column operation close to optimal in a "self-optimizing" control scheme.
Research of Neuron Growth Prediction and Influence of Its Geometric Configuration  [PDF]
Tao Sun, Liang Lin, Qiaoyu Huang
Applied Mathematics (AM) , 2011, DOI: 10.4236/am.2011.27121
Abstract: The neuron growth will bring series variation to the neuron characteristics of geometric configuration. Especially the growth of dendrite and axon can obviously change the space characteristic and geometric characteristic of neuron. This article is to build the prediction model of neuron growth through knowing the statistics rules of neuron geometric characteristics, better imitate the neuron growth, and clearly analyze the growth influence of geometric configuration.
Configuration Mode of Ornamental Plants in Norbulingka of Tibet and Application of Landscape Color  [PDF]
Wenbo Li, Zhen Xing, Zhenji Suolang, Jiangping Fang
Current Urban Studies (CUS) , 2018, DOI: 10.4236/cus.2018.62016
The application of plant landscape color has a great effect on the landscape of the scenic spot. By colorful foliage and ornamental plants with high color recognition, visitors can deepen their impressions, and thus increase the landscape aesthetic expectations and psychological recognition of the landscape sense. The plants in Norbulingka were taken as research object in this paper. Via field investigation and consulting a lot of data, color characters of ornamental plants from each genus and family were identified from the angle of plant characteristics of arbor, shrub and herb. CMYK color card value was used to collect color data of leaves, flowers and fruits from different plants, and quantitative analysis on color difference of leaves, flowers and fruits from ornamental plants was conducted, to obtain evaluation method and reasoning basis of plant color design in Norbulingka. The results showed that: 1) in color values of leaves, percentage of purple herb = red shrub; cyan herb > light green herb, dark green arbor > grass green arbor, yellow shrub > jade green shrub, bitter orange arbor < bottle green arbor; 2) in color values of flowers, percentage of bitter orange herb < blue shrub, cyan herb > light green herb, dark green arbor > grass green arbor, yellow shrub > jade green shrub, bitter orange arbor < bottle green arbor; 3) in color values of fruits, percentage of purple shrub > yellow shrub, yellow arbor > red arbor, blue herb = green arbor, red shrub < green shrub.
Optimizing the Teaching Strategies of the Novice, Proficient and Expert College English Teachers  [PDF]
Jiafeng Liu, Qingshun He
Creative Education (CE) , 2014, DOI: 10.4236/ce.2014.513126

The teaching strategy plays an important part in the effectiveness of the college English teaching. After comparing the current college English teaching strategies in China, this paper attempts to analyze the process teaching strategies and the cognitive teaching strategies of the novice, the proficient and the expert college English teachers at different teaching stages of teaching and proposes the optimizing path of the teaching strategies. This helps make up for the lack of research of enhancing the college English teaching strategies inChina.

Quantum-Inspired Bee Colony Algorithm  [PDF]
Guorui Li, Mu Sun, Panchi Li
Open Journal of Optimization (OJOp) , 2015, DOI: 10.4236/ojop.2015.43007
Abstract: To enhance the performance of the artificial bee colony optimization by integrating the quantum computing model into bee colony optimization, we present a quantum-inspired bee colony optimization algorithm. In our method, the bees are encoded with the qubits described on the Bloch sphere. The classical bee colony algorithm is used to compute the rotation axes and rotation angles. The Pauli matrices are used to construct the rotation matrices. The evolutionary search is achieved by rotating the qubit about the rotation axis to the target qubit on the Bloch sphere. By measuring with the Pauli matrices, the Bloch coordinates of qubit can be obtained, and the optimization solutions can be presented through the solution space transformation. The proposed method can simultaneously adjust two parameters of a qubit and automatically achieve the best match between two adjustment quantities, which may accelerate the optimization process. The experimental results show that the proposed method is obviously superior to the classical one for some benchmark functions.
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