The objectives of this study were to develop and subsequently demonstrate a parameter prediction approach for estimating black spruce (Picea mariana (Mill.) BSP) diameter frequency distributions within the context of a stand density management diagram (SDMD). The approach consisted of three sequential steps: (1) obtaining maximum likelihood estimates for the location, scale and shape parameters of the Weibull probability density function for 153 empirical diameter frequency distributions; (2) developing and evaluating parameter prediction equations in which the Weibull parameter estimates were expressed as functions of stand-level variables based on stepwise regression and seemingly unrelated regression techniques; and (3) explicitly incorporating the parameter prediction equations into the SDMD modelling framework. The results indicated that the Weibull function was successful in characterizing the diameter distributions within the sample stands: the fitted distributions exhibited no significant (p ≤ 0.05) differences in relation to their corresponding observed distributions, based on the Kolmogorov-Smirnov test. The parameter prediction equations described 94, 94 and 89% of the variation in the location, scale and shape parameter estimates, respectively. Furthermore, evaluation of the recovered distributions in terms of prediction error indicated minimal biases and acceptable accuracy. As demonstrated, incorporating the parameter prediction equations into an algorithmic version of the SDMD enabled the prediction of the temporal dynamics of the diameter frequency distribution by initial density regime and site quality. Additionally, an executable version of the resultant algorithm with instructions on acquiring it via the Internet is provided.Key words: 3-parameter Weibull probability density function, stepwise and seemingly unrelated regression, predictive error, product value, algorithm, Internet Les objectifs de cette étude étaient de développer et par la suite d'utiliser une approche de récupération de paramètres pour estimer les distributions de fréquence de diamètre de l'épinette noire (Picea mariana (Mill.) BSP) dans le cadre d'un diagramme d'aménagement de la densité d'un peuplement (SDMD). L'approche comportait trois étapes séquentielles : (1) l'obtention du maximum vraisemblable d'estimés pour les paramètres du site, de l'échelle et de la forme de la fonction de probabilité de densité de Weibull pour 153 distributions empiriques de fréquence de diamètre; (2) le développement et l'évaluation des équations de récupération des paramètres dans lesquelles les estimés des paramètres selon Weibull étaient exprimés en tant que fonctions des variables du peuplement selon des techniques de régressions par étape et d'autres techniques de régression apparemment sans rapport, et (3) l'intégration explicite des équa-tions de récupération des paramètres dans le cadre du travail de modélisation SDMD. Les résultats démontrent que la fonction Weibull a réussi à représenter les caractéristiques des distributions de diam...

Concrete distributor is one of the key equipment for the industrial production of concrete product parts. Its performance directly affects the product quality and production efficiency of precast concrete components, which in turn affects the level of architecture industrialization of China. At present, the domestic concrete distributor has a low degree of automation and a simple mechanical structure. There is too much manual intervention in the production. It is impossible to achieve a real automatic distribution. Also, BIM data cannot be shared with the control system, resulting in low production efficiency. This paper summarized these problems which are in the context of big data, internet of things and intelligence, and proposed the upgrade ideas for precast concrete components production equipment. In order to break through the bottleneck that restricts the stability, refinement and intelligent development of precast concrete components distribution. The research and exploration in BIM data analysis mechanical structure optimization and control system upgrade were conducted. Then the overall development of mechanical equipment that meets construction standards of China will be promoted.