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21.
Contrary to popular belief, biologists discovered that worker ants are really not all hardworking. It has been found that in three separate 30-strong colonies of black Japanese ants (Myrmecina nipponica), about 20% of worker ants are diligent, 60% are ordinary, and 20% are lazy. That is called 20:60:20 rule. Though they are lazy, biologists suggested that lazy worker ants could be contributing something to the colony that is yet to be determined. In our last research, we used CHC (cross generational elitist selection, heterogeneous recombination, and cataclysmic mutation) with the worker ants’ rule (WACHC) aiming at solving optimization problems in changing environments. CHC is a nontraditional genetic algorithm (GA) which combines a conservative selection strategy that always preserves the best individuals found so far with a radical (highly disruptive) recombination operator. In our last research, we verified that WACHC performs better than CHC in only one case of fully changing environment. In this paper, we further discuss our proposed WACHC dealing with changing environment problems with varying degree of difficulty, compare our proposal with hypermutation GA which is also proposed for dealing with changing environment problems, and discuss the difference between our proposal and ant colony optimization algorithms. 相似文献
22.
Masuda N 《Neural computation》2006,18(1):45-59
Firing rates and synchronous firing are often simultaneously relevant signals, and they independently or cooperatively represent external sensory inputs, cognitive events, and environmental situations such as body position. However, how rates and synchrony comodulate and which aspects of inputs are effectively encoded, particularly in the presence of dynamical inputs, are unanswered questions. We examine theoretically how mixed information in dynamic mean input and noise input is represented by dynamic population firing rates and synchrony. In a subthreshold regime, amplitudes of spatially uncorrelated noise are encoded up to a fairly high input frequency, but this requires both rate and synchrony output channels. In a suprathreshold regime, means and common noise amplitudes can be simultaneously and separately encoded by rates and synchrony, respectively, but the input frequency for which this is possible has a lower limit. 相似文献
23.
The radiance and degree of linear polarization of the upward radiation emerging from the top of the terrestrial atmosphere bounded by a ruffled ocean surface are computed in the wavelength region ranging from 0.40 to 0.80 microm with the aid of the adding method. The ruffled ocean surface is treated as an interacting interface, where the radiation transmitted diffusely from below the ocean surface into the atmosphere is also taken into account. Computational results show that the simultaneous measurement of radiance and polarization degree from space makes it possible to derive atmospheric and oceanic parameters. 相似文献
24.
The relationship between striation spacing and fatigue crack propagation rate up to 70 m/cycle was investigated for a ductile structural steel, qualified as JIS SM58Q. A modified compact-type specimen 400 mm wide and a centre-cracked specimen 200 mm wide were tested at a stress ratio, R, of 0 and 0.8. The fracture surface of the specimen was examined in detail under a scanning electron microscope. The crack propagation rate was expressed by a power function of the range of stress intensity factor from 0.1 to 70 m/cycle for R=0 and to 0.5 m/cycle for R=0.8. The striation spacing coincided with the fatigue crack propagation rate over the range 0.1 to 70 m/cycle. The profile of striation was found to be a ridge and valley type, and the ridges on one fracture surface coincided with those on the matching surface. It is suggested that the striation is formed by a plastic blunting mechanism. 相似文献
25.
Periodic flooding alters riverine vegetation community composition; moderate flood disturbance maintains communities at an early seral stage, whereas severe floods may remove entire communities. After disturbance, plants may recolonize riverbeds from refugia.Here, we investigated the morphological characteristics of refugia where riverine plants survived large floods. At three sites, plant communities growing on cobble-bars were surveyed, and the hydraulic characteristics of each site were analyzed. The populations of an indicator plant, Anaphalis margaritacea sub-species yedoensis (Franch. et Savat.) were assessed after major floods in 2004 and 2009. At each survey, the particle size and bed composition were measured, and the critical shear-stress required to move particles at each site was calculated. A one-dimensional flow and the average and local shear-stress at ten different discharges, including that of the largest flood were calculated. The results demonstrate that the A. margaritacea community is maintained at locations where the local shear-stress at peak discharge in large-floods does not exceed a critical value. These conditions were achieved in locations with particular morphological characteristics, where the river is not constrained by levees and is restricted by a downstream narrow-pass; in this reach river width increases with discharge thus limiting the increase in water depth with increasing discharge and allowing the establishment of refugia where plant species may survive large floods.Flooding and reestablishment from refugia maintain a characteristic riverbed community in equilibrium. 相似文献
26.
The field dependence of the magnetic susceptibility at low temperatures was investigated in a single crystal of Cs2NaHoCl6. The result is well explained by the second-order Zeeman splitting of the electronic ground state with a nonmagnetic 3 doublet. Enhanced nuclear cooling experiments were carried out. Antiferromagnetic ordering of the enhanced nuclear spin system was observed at about 1.5 mK. 相似文献
27.
28.
Reiji Hattori Shuhei Yamada Yoshitomo Masuda Norio Nihei 《Journal of the Society for Information Display》2004,12(1):75-80
Abstract— We have developed new powder materials that exhibit liquid behavior, which can lead to the realization of novel bistable and reflective displays having paper‐white appearance, high contrast, and quick response. Two types of display were demonstrated, one had 160 × 160 array of pixels and the other had 320 × 320 in a 3.1‐in.‐diagonal viewable image size corresponding to 66 and 132 dpi, respectively. These displays were driven by passive‐matrix addressing. The displays showed a reflectivity of more than 41%, a contrast more than 1:10, and a pixel response time of less than 0.2 msec. The seven‐segment display for use in clocks was also demonstrated. 相似文献
29.
研究了粉末冶金机械零件使用的烧结材料的杨氏模量、切变模量及泊松比与孔隙度的关系.制备了三种钢粉,在不同条件下进行了压制、烧结与热处理.孔隙度对杨氏模量、切变模量及泊松比的影响最大.特别是泊松比还受孔隙形状的影响,而孔隙形状随粉末类型、烧结温度与烧结气氛及热处理条件而变化.对于大部分实际应用的粉末组成来说,烧结气氛对经烧结和热处理后材料的泊松比影响不大.对于部分预合金化粉末(Fe4%Ni1.5%Cu0.5%Mo)+0.8%石墨,只有在孔隙度低于20%时,烧结温度对泊松比与孔隙度的关系才有影响.在这种情况下.提出了烧结与热处理试样泊松比与孔隙度关系的较简单近似方程:在烧结温度1 423K下,v=0.300-0.266P+0.579P2;在烧结温度1 523K下,v=0.304-0.264P+0.548P2. 相似文献
30.
A Ozaki M Kitano N Itoh K Kuroda N Furusawa T Masuda H Yamaguchi 《Canadian Metallurgical Quarterly》1998,36(9-10):811-817
Five synthetic food colours Food Red Nos 3, 40 and 102 and Food Blue Nos 1 and 2, and their UV irradiated products were tested for mutagenic activity by means of the Ames test using Salmonella typhimurium strains TA98 and TA100. Food colours were irradiated with UV light for 14 days. Food Red Nos 3, 40 and 102 and Food Blue No. 1 were non-mutagenic before and after irradiation. UV irradiated products of Food Blue No. 2 were mutagenic in TA98 with or without S-9 mix. The mutagenic activity increased with increasing irradiation period, reached maximum potency on day 6, and then decreased. Moreover, Food Blue No. 2 showed DNA-damaging activity after 14 days of irradiation in rec-assay using Bacillus subtilis strains H17 and M45. The capillary electrophoresis was applied for the analysis of UV irradiated products of Food Blue No. 2. The original peak of Food Blue No. 2 was decomposed into seven peaks after UV irradiation. 相似文献