平面连杆机构的优化设计

利用单变参数（辅助角）按最佳传动角及最大行程速度变化系数对曲柄摇杆机构进行优化设计，提高了机构设计质量，方法实用可行。     

Statistical Inference under Symmetry

We explore the consequences of adjoining a symmetry group to a statistical model. Group actions are first induced on the sample space, and then on the parameter space. It is argued that the right invariant measure induced by the group on the parameter space is a natural non-informative prior for the parameters of the model. The permissible sub-parameters are introduced, i.e., the subparameters upon which group actions can be defined. Equivariant estimators are similarly defined. Orbits of the group are defined on the sample space and on the parameter space; in particular the group action is called transitive when there is only one orbit. Credibility sets and confidence sets are shown (under right invariant prior and assuming transitivity on the parameter space) to be equal when defined by permissible sub-parameters and constructed from equivariant estimators. The effect of different choices of transformation group is illustrated by examples, and properties of the orbits on the sample space and on the parameter space are discussed. It is argued that model reduction should be constrained to one or several orbits of the group. Using this and other natural criteria and concepts, among them concepts related to design of experiments under symmetry, leads to links towards chemometrical prediction methods and towards the foundation of quantum theory.     

Inventory ordering policies of delayed deteriorating items under permissible delay in payments

The existing literature on inventory of deteriorating items considers deterioration to begin as soon as the items are stocked. However, there are several deteriorating items that do not start deteriorating immediately they are held in stock. Some farm produce like potatoes, yams and even some fruits and vegetables have this property. Depletion of these items as soon as they are stocked will depend on demand, and when deterioration begins, it will depend on both demand and deterioration. In this paper, we develop a mathematical model on the inventory of deteriorating items that do not start deteriorating immediately they are stocked. The model also takes into cognizance the fact that in business activities nowadays customers are given some allowed period within which to settle for the goods supplied to them. They can use the accrued money from sales of the supplied goods to earn interest within the allowed period. They are charged interest only when they fail to settle the amount they owe the supplier at the end of the allowed period.