Optimal number and allocation of controls among serial production stages

1994 ◽  
Vol 9 (6) ◽  
pp. 398-407 ◽  
Author(s):  
Helman I. Stern ◽  
Shaul P. Ladany
2017 ◽  
Vol 44 (3) ◽  
pp. 475-488 ◽  
Author(s):  
Massoud Khazabi ◽  
Nguyen Van Quyen

Purpose The purpose of this paper is to extend a theoretical framework for analyzing competition and innovation in the presence of horizontal spillovers. Design/methodology/approach A theoretical analysis approach is adopted to drive the paper’s findings. Findings It is shown that when firms behave non-cooperatively in both the R&D and production stages, the degree of spillover has a negative relationship with the effective and respective R&D expenditures of each firm as well as the level of social welfare. An inverted-U relationship between competition and social welfare also holds. When firms behave cooperatively in the R&D stage, and non-cooperatively in the production stage the relationship between the R&D expenditure of the joint research lab and the number of firms in the market is negative. Originality/value In the literature on R&D spillovers and process innovation, efforts are mostly focused on the comparative R&D expenditures and the relative social welfare between non-cooperative and cooperative R&D. The question of the effectiveness of R&D technology on the optimal number of firm, however, is not explicitly addressed. The paper is intended to address this lacuna.


Author(s):  
I. C. Dima

Polyservicing the workplaces takes into account the cycle of processing the benchmarks by machine tools and their features and implies a thorough analysis of the technical, organisational, and economic aspects. It is thus intended to efficiently use the machines and machine tools including the worker’s working time. Grouping the processing operations by machine tools will be done depending on the technological structure of each operation, given the use index of the machines, the effective use index of labour, the structure and duration of the operations necessary to make the product, the type of the machine tools used. Polyservicing the machine-tools is featured by a series of parameters: the duration of the working cycle of a machine, the duration of the polyservicing cycle, optimal number of machines that can be services, the coefficient to use the performer’s working time, etc. Combining the operations to be done on various machine tools is based on the types of technological processes and is done separately for manufacturing unique products, serial production, and mass production. Establishing the optimal production conditions for polyservicing can be done by using the theory of “waiting queues” and “Markov chain,” which is based on three elements, namely: input into the process, the servicing mechanism, and the type and way of servicing. Optimising the polyservice of machines can be done using the “Takacs and Runnenburg model,” which basically solves the issue of the general distribution of servicing times and the “method of the mechanisation coefficient,” which takes into account the influence of cost on the number of polyserviced machines.


2013 ◽  
Vol 221 (3) ◽  
pp. 145-159 ◽  
Author(s):  
Gerard J. P. van Breukelen

This paper introduces optimal design of randomized experiments where individuals are nested within organizations, such as schools, health centers, or companies. The focus is on nested designs with two levels (organization, individual) and two treatment conditions (treated, control), with treatment assignment to organizations, or to individuals within organizations. For each type of assignment, a multilevel model is first presented for the analysis of a quantitative dependent variable or outcome. Simple equations are then given for the optimal sample size per level (number of organizations, number of individuals) as a function of the sampling cost and outcome variance at each level, with realistic examples. Next, it is explained how the equations can be applied if the dependent variable is dichotomous, or if there are covariates in the model, or if the effects of two treatment factors are studied in a factorial nested design, or if the dependent variable is repeatedly measured. Designs with three levels of nesting and the optimal number of repeated measures are briefly discussed, and the paper ends with a short discussion of robust design.


Author(s):  
M. Novokhatskyi ◽  
◽  
V. Targonya ◽  
T. Babinets ◽  
O. Gorodetskyi ◽  
...  

Aim. Assessment of the impact of the most common systems of basic tillage and biological methods of optimization of nutrition regimes on the realization of the potential of grain productivity of soybean in the Forest-Steppe of Ukraine. Methods. The research used general scientific (hypothesis, experiment, observation) and special (field experiment, morphological analysis) methods Results. The analysis of the results of field experiments shows that the conservation system of soil cultivation, which provided the formation of 27.6 c/ha of grain, is preferable by the level of biological yield of soybean. The use of other systems caused a decrease in the biological yield level: up to 26.4 c/ha for the use of the traditional system, up to 25.3 c/ha for the use of mulching and up to 23.0 c/ha for the use of the mini-till. With the use of Groundfix, the average biological yield of soybean grain increases to 25.6 c / ha for application rates of 5 l/ha, and to 28.2 c/ha for application rates of 10 l/ha when control variants (without the use of the specified preparation) an average of 22.6 c/ha of grain was formed with fluctuations in soil tillage systems from 21.0 (mini-bodies) to 25.8 c/ha (traditional).The application of Groundfix (10 l/ha) reduced the seed abortion rate from 11.0% (average without biofertilizer variants) to 8.0%, forming the optimal number of stem nodes with beans, increasing the attachment height of the lower beans and improving other indicators of biological productivity soybeans. Conclusions. It has been found that the use of the canning tillage system generates an average of 27.6 cent soybean grains, which is the highest indicator among the main tillage systems within the scheme of our research. The use of Groundfix caused a change in this indicator: if the variants with a conservative system of basic tillage without the use of biological preparation (control) were formed on average 24.1 c/ha, the use of Ground Licks caused the increase of biological productivity up to 29.4 c/ha, and at a dose of 10 l/ha biological yield was 32.2 c/ha. It was found that both the use of Groundfix and the basic tillage system influenced the elements of the yield structure: the density of the plants at the time of harvest depended more on the tillage system than on the use of Groundfix; the use of Groundfix and increasing its dose within the scheme of our studies positively reflected on the density of standing plants; the height of attachment of the lower beans and reduced the abortion of the seeds.


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