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71.
One of the most complicated ANN models, the neocognitron (NC), is adapted to an efficient all-digital implementation for VLSI. The new model, the digi-neocognitron (DNC), has the same pattern recognition performance as the NC. The DNC model is derived from the NC model by a combination of preprocessing approximation and the definition of new model functions, e.g., multiplication and division are eliminated by conversion of factors to powers of 2, requiring only shift operations. The NC model is reviewed, the DNC model is presented, a methodology to convert NC models to DNC models is discussed, and the performances of the two models are compared on a character recognition example. The DNC model has substantial advantages over the NC model for VLSI implementation. The area-delay product is improved by two to three orders of magnitude, and I/O and memory requirements are reduced by representation of weights with 3 bits or less and neuron outputs with 4 bits or 7 bits. 相似文献
72.
For heat treating cylindrical metal billets, their lay-out in a furnace usually resembles that of an in-line heat-exchanger tube bank, with the air flows orthogonal to the billets. For maximum effectiveness of transferring thermal energy from the forced convecting air to the billets, the optimal horizontal pitch-to-diameter ratio for the billets should be 1·33 ± 0·05. For this same purpose it is advantageous to employ a vertical spacing (between the billets) as large as can be permitted for a given load of billets. 相似文献
73.
The conditioned cue preference (CCP) task was used to study the information required to discriminate between spatial locations defined by adjacent arms of an 8-arm radial maze. Normal rats learned the discrimination after 3 unreinforced preexposure (PE) sessions and 4 food paired-unpaired training trials. Fimbria-fornix lesions made before, but not after, PE, and hippocampus lesions made at either time, blocked the discrimination, suggesting that the 2 structures processed different information. Lateral amygdala lesions made before PE facilitated the discrimination. This amygdala-mediated interference with the discrimination was the result of a conditioned approach response that did not discriminate between the 2 arm locations. A hippocampus/fimbria-fornix system and an amygdala system process different information about the same learning situation simultaneously and in parallel. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
74.
75.
W J Cole P J Eppard B G Boysen K S Madsen R H Sorbet M A Miller R L Hintz T C White W E Ribelin B G Hammond 《Journal of dairy science》1992,75(1):111-123
Eighty-two lactating Holstein cows in their first, second, or third lactation received either one, three, or five concurrent i.m. injections of a unit dose (.6 g) of zinc methionyl bST (sometribove) or five doses of the vehicle. Injections were given at 14-d intervals from 60 +/- 3 d postpartum until the end of lactation or necropsy. Thirty-eight animals were continued on treatment for a 2nd yr. Sometribove did not affect the incidence of ketosis, milk fever, tetany, or pneumonia. Digestive disorders, primarily cows going off feed, were increased by bST during yr 1 only. The incidence of lameness was increased by bST in some time frames because of an increase in the 3.0-g bST group. Lameness was not associated with treatment-specific histopathologic changes or with abnormalities in cartilage or bone. Reproductive health generally was unaffected by treatment, but delayed conception and increased incidence of abortion were noted. Incidence of cystic ovaries was unaffected by bST. Pregnancy rates were decreased during the 100-d breeding interval of yr 1 but not during the 215-d interval of yr 2. The incidence of clinical mastitis was increased by bST, primarily at the 3.0-g dose. During the 2-yr study, 0, 3, 3, and 2 cows died or became moribund on 0, .6, 1.8, and 3.0 g of bST, respectively. Health issues identified for further evaluation included lameness and clinical mastitis for the 3.0-g group and early removal from the herd and decreased reproductive performance for all bST groups. Bovine somatotropin caused no treatment-specific toxic effects in dairy cows even at 3.0 g every 14 d. 相似文献
76.
Mercado L.L. White J. Sarihan V. Lee T.-Y.T. 《Components and Packaging Technologies, IEEE Transactions on》2003,26(3):509-516
Anisotropic conductive film (ACF) consists of an adhesive polymer matrix with dispersed conductive particles. In flip-chip technology, ACF has been used in place of solder and underfill for chip attachment to glass or organic substrates. The filler particles establish the electrical contacts between the interconnecting areas. ACF flip-chip bonding provides finer pitch, higher package density, reduced package size and improved lead-free compatibility. Nevertheless, the interconnection is different from traditional solder joints, the integrity and durability of the ACF interconnects have major concerns. Failures in anisotropic conductive film (ACF) parts have been reported after temperature cycling, moisture preconditioning and autoclave. The failures have not been well understood and have been attributed to a wide variety of causes. This paper investigates the failure mechanism of ACF using finite element simulation. From a failure-initiation point of view, the response of ACF packages to environmental (temperature and humidity) exposure is very different from standard underfilled packages. These differences cause the ACF package to fail in different ways from an underfilled package. Simulation results have shown that moisture-induced ACF swelling and delamination is the major cause of ACF failure. With moisture absorption, the loading condition at the interface is tensile-dominant, which corresponds to lower interface toughness (or fracture resistance). This condition is more prone to interface delamination. Therefore, the reliability of ACF packages is highly dependent on the ACF materials. The paper suggests a new approach toward material selection for reliable ACF packages. This approach has very good correlation with experimental results and reliability testing of various ACF materials. 相似文献
77.
CP Van Schayck 《Canadian Metallurgical Quarterly》1996,46(404):193-197
There may be an overlap between the clinical pictures of asthma and chronic obstructive pulmonary disease which hampers a clear distinction between the two diseases. Most symptoms presented by patients do not clearly belong exclusively to either asthma or chronic obstructive pulmonary disease. By the nature of their discipline and training, general practitioners focus mainly on symptoms presented, which do not give a decisive answer in the differential diagnosis between the two diseases. Therefore, general practitioners must rely on objective parameters, such as determining the presence and degree of reversibility of airway obstruction, diurnal peak flow variability, bronchial hyper-responsiveness and allergy. This paper puts forward a pragmatic, primary care definition of asthma and chronic obstructive pulmonary disease. 相似文献
78.
One hundred and seven consecutive patients presenting with significant peptic ulcer haemorrhage were randomised to endoscopic injection with 3-10 ml of 1:100,000 adrenaline (55 patients, group 1) or to a combination of adrenaline and 5% ethanolamine (52 patients, group 2). All had major stigmata of haemorrhage and endoscopic injection was undertaken by a single endoscopist. The groups were well matched with regard to risk factors. Rebleeding occurred in eight of the group 1 patients and seven in the group 2 patients; surgical operation rates, median blood transfusion requirements, and hospital stay were similar in both groups. The efficacy of either form of injection was similar whether patients presented with active bleeding or a non-bleeding visible vessel. No complications occurred. In patients presenting with significant peptic ulcer bleeding, the addition of a sclerosant confers no advantage over injection with adrenaline alone. 相似文献
79.
80.
The fumonisins are inhibitors of de novo sphingolipid biosynthesis in vitro and in vivo and thus possibly interfere with the regulation of cell growth, differentiation, and neoplastic transformation. In addition, the ratio of free sphinganine (Sa) to free sphingosine (So) has been proposed as a marker of exposure for animals or humans consuming feed or food contaminated by these toxins. A method to analyze these sphingolipid bases has been proposed [Merrill et al., 1988: Anal Biochem 171:373-381; Riley et al., 1994a: JAOAC 77:533-540] but involves numerous steps and consequently is not ideally suited to the analysis of large numbers of samples, as is often required in epidemiological studies. A new method was therefore developed for the analysis of the Sa/So ratio in tissues as well as human and rat urine. Briefly, the method involves isolation of exfoliated cells from as little as 0.5 ml of rat urine or 2 ml of human urine followed by a rapid and efficient extraction of sphingolipid bases in ethyl acetate, an optimized derivatization step with o-phthaldialdehyde and a high-pressure liquid chromatography separation on a 250 mm x 4.6 mm. 5 microns Kromasil C18 column, with a 4-step phosphate buffer/methanol gradient. Fluorescence was monitored at 340 nm excitation, 455 nm emission, and retention times for So, Sa, and C-20 Sa were about 11, 14, and 22 min, respectively. The method was adapted to tissue analysis by partially digesting approximately 30 mg tissue with trypsin to permit isolation of a cell pellet before extraction of the sphingolipids as described above. The method was applied to the analysis of So and Sa in urines and tissues of fumonisin B1 (FB1) treated and untreated male BDIV rats. The Sa/So ratio in urine of untreated rats varied from 0.1 to 0.7, and for treated rats (between 1-5 mg FB1/kg body weight daily by gavage), the ratio was between 1.2-10. In kidney, the ratio was 0.1 in control rats and varied from 4 to 10.3 in treated rats. In human urine, measurements could easily be made in 2 ml of urine in females, but in males much larger volumes were required due to the low levels of sphingolipid bases. 相似文献