排序方式: 共有15条查询结果,搜索用时 46 毫秒
1.
2.
Neural networks (NNs) are appropriate to use in time series analysis under conditions of unfulfilled assumptions, i.e., non‐normality and nonlinearity. The aim of this paper is to propose means of addressing identified shortcomings with the objective of identifying the NN structure for inflation forecasting. The research is based on a theoretical model that includes the characteristics of demand‐pull and cost‐push inflation; i.e., it uses the labor market, financial and external factors, and lagged inflation variables. It is conducted at the aggregate level of euro area countries from January 1999 to January 2017. Based on the estimated 90 feedforward NNs (FNNs) and 450 Jordan NNs (JNNs), which differ in variable parameters (number of iterations, learning rate, initial weight value intervals, number of hidden neurons, and weight value of the context unit), the mean square error (MSE), and the Akaike Information Criterion (AIC) are calculated for two periods: in‐the‐sample and out‐of‐sample. Ranking NNs simultaneously on both periods according to either MSE or AIC does not lead to the selection of the ‘best’ NN because the optimal NN in‐the‐sample, based on MSE and/or AIC criteria, often has high out‐of‐sample values of both indicators. To achieve the best compromise solution, i.e., to select an optimal NN, the preference ranking organization method for enrichment of evaluations (PROMETHEE) is used. Comparing the optimal FNN and JNN, i.e., FNN(4,5,1) and JNN(4,3,1), it is concluded that under approximately equal conditions, fewer hidden layer neurons are required in JNN than in FNN, confirming that JNN is parsimonious compared to FNN. Moreover, JNN has a better forecasting performance than FNN. 相似文献
3.
4.
Tea Chieli Daniela Cocchi G. B. Fregnan E. E. Müller 《Cellular and molecular life sciences : CMLS》1980,36(4):463-465
Summary Oral administration of 2 neuroleptic drugs, haloperidol and LR511 induced in male rats a marked, dose-dependent and sustained rise of plasma prolactin. 相似文献
5.
C. Bertazzoli T. Chieli M. Grandi G. Ricevuti 《Cellular and molecular life sciences : CMLS》1970,26(4):389-390
Riassunto Si è studiato sperimientalmente la tossicologia acuta e subacuta dell'adriamicina, un nuovo antibiotico antitumorale con struttura simile a quella della daunomicina, rilevandone l'attività depressiva sulla riproduzione cellulare. 相似文献
6.
7.
8.
Riassunto La 2-sulfanilamido, 3-metossi-pirazina, a differenza della 2-sulfanilamido, 4-6-dimetossi-pirimidina, non induce malformazioni dentarie nella prole, qualora venga somministrata al ratto durante la gestazione. 相似文献
9.
Lordkipanidze D Jashashvili T Vekua A Ponce de León MS Zollikofer CP Rightmire GP Pontzer H Ferring R Oms O Tappen M Bukhsianidze M Agusti J Kahlke R Kiladze G Martinez-Navarro B Mouskhelishvili A Nioradze M Rook L 《Nature》2007,449(7160):305-310
The Plio-Pleistocene site of Dmanisi, Georgia, has yielded a rich fossil and archaeological record documenting an early presence of the genus Homo outside Africa. Although the craniomandibular morphology of early Homo is well known as a result of finds from Dmanisi and African localities, data about its postcranial morphology are still relatively scarce. Here we describe newly excavated postcranial material from Dmanisi comprising a partial skeleton of an adolescent individual, associated with skull D2700/D2735, and the remains from three adult individuals. This material shows that the postcranial anatomy of the Dmanisi hominins has a surprising mosaic of primitive and derived features. The primitive features include a small body size, a low encephalization quotient and absence of humeral torsion; the derived features include modern-human-like body proportions and lower limb morphology indicative of the capability for long-distance travel. Thus, the earliest known hominins to have lived outside of Africa in the temperate zones of Eurasia did not yet display the full set of derived skeletal features. 相似文献
10.