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261.
The dark adaptation behaviors of rod-driven and cone-driven horizontal cells were exam-ined by analyzing their light responses recorded intracellularly in the intact, immobilizedcarp, and compared with that of the electroretinographic b--wave recorded simultaneously.Like the b--wave, the light responsiveness of rod horizontal cells increased gradually withtime in the dark and attained a steady level at 60 min. On the other hand, cone horizontalcells initially increased in light responsiveness in the first 10 min, but thereafter decreasedsteadily so that the response amplitudes of these cells to bright light flashes were only 3--5 mV.The results suggest that cone horizontal cells are strongly suppressed in prolonged darkness. 相似文献
262.
G. Kjellström 《Journal of Optimization Theory and Applications》1991,71(3):589-597
Gaussian Adaptation (GA) is a stochastic process that adapts a Gaussian distribution to a region or set of feasible points in parameter space. As a result of the adaptation, GA becomes a maximum dispersion process extending the sampling over the largest possible volume in parameter space while keeping the probability of finding feasible points at a suitable level. For such a process, a general measure of efficiency is defined and an efficiency theorem is proved. 相似文献
263.
Juan?L.?NievesEmail author Eva?Valero Javier?Hernández-Andrés Javier?Romero 《Optical Review》2003,10(4):221-230
We report on experiments in which observers judged colour appearance within the context of time-varying colour adaptation. We used pairs of contextual images consisting of a rapid succession of colour surfaces reproduced under different illuminants to analyse the effect of temporal colour adaptation rather than a spatial context on asymmetric matching and also to judge its influence upon the cone excitation components. We used adaptation colour distributions along the red-green and yellow-blue axes (selective conditions) and random colour distributions (non-selective condition). The results of observers’ matches for both conditions showed approximate colour-constant appearance. Although light adaptation did not fully compensate the colour changes, we obtained average colour-constancy index values of 0.6. The results for the two opponent conditions showed similar contextual effects. No significant differences between each condition were found for the L- and S-cone mechanisms and the three test illuminants. On the contrary, some degree of interaction between the comparison-field cone excitations and the colour axis can be seen when the colour mechanisms are analysed separately. This seems to be more pronounced for the S-cone mechanism and suggests that the selective condition of the adaptation sequence may well affect the observer’s chromatic matching response. 相似文献
264.
Pontawee Pungrassamee Mitsuo Ikeda Pichayada Katemake Aran Hansuebsai 《Optical Review》2005,12(3):211-218
The color appearance was measured for a test patch which was placed in a test room illuminated by daylight lamps and was looked at from a subject room illuminated by one of four colored illuminations, red, yellow, green and blue, through windows of various sizes. When the window was small so that only the test patch was seen within the window the color of the test patch appeared almost opponent to the illumination color, but as soon as something was seen within the window of a larger size the color returned to the original color of the test patch. To recognize the test room as a space was essential to perceive the real color of the test patch. The results were explained by the concept of the recognized visual space of illumination. 相似文献
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提出全同粒子模型进一步解释视网膜与视皮层之间的联系,根据辐射与物质相互作用的时间量子理论研究全同粒子系统的辐射跃迁.模型显示,全同粒子系统的亚辐射态对外界没有响应,超辐射态的辐射跃迁几率是粒子数的非线性函数.对视觉细胞与视色素各自的相干性和视觉明暗适应中视网膜与视皮层之间协同作用的初步解释支持全同粒子模型.因此,全同粒子模型对视觉适应成立,它与Retinex理论的结合将为视觉适应的进一步研究提供新的线索. 相似文献
269.
Stock investors usually make their short-term investment decisions according to recent stock information such as the late market news, technical analysis reports, and price fluctuations. To reflect these short-term factors which impact stock price, this paper proposes a comprehensive fuzzy time-series, which factors linear relationships between recent periods of stock prices and fuzzy logical relationships (nonlinear relationships) mined from time-series into forecasting processes. In empirical analysis, the TAIEX (Taiwan Stock Exchange Capitalization Weighted Stock Index) and HSI (Heng Seng Index) are employed as experimental datasets, and four recent fuzzy time-series models, Chen’s (1996), Yu’s (2005), Cheng’s (2006) and Chen’s (2007), are used as comparison models. Besides, to compare with conventional statistic method, the method of least squares is utilized to estimate the auto-regressive models of the testing periods within the databases. From analysis results, the performance comparisons indicate that the multi-period adaptation model, proposed in this paper, can effectively improve the forecasting performance of conventional fuzzy time-series models which only factor fuzzy logical relationships in forecasting processes. From the empirical study, the traditional statistic method and the proposed model both reveal that stock price patterns in the Taiwan stock and Hong Kong stock markets are short-term. 相似文献
270.
Ritesh Kumar Dubey Prabhat Mishra 《Numerical Methods for Partial Differential Equations》2023,39(1):108-132
It is well known that on uniform mesh classical higher order schemes for evolutionary problems yield an oscillatory approximation of the solution containing discontinuity or boundary layers. In this article, an entirely new approach for constructing locally adaptive mesh is given to compute nonoscillatory solution by representative “second” order schemes. This is done using modified equation analysis and a notion of data dependent stability of schemes to identify the solution regions for local mesh adaptation. The proposed algorithm is applied on scalar problems to compute the solution with discontinuity or boundary layer. Presented numerical results show underlying second order schemes approximate discontinuities and boundary layers without spurious oscillations. 相似文献