Selective photofacilitated transport of sodium ions through liquid membranes: key factors in experimental design, transport results and comparison with a mathematical model

2003 ◽  
Vol 212 (1-2) ◽  
pp. 225-235 ◽  
Author(s):  
Michelle L. Goyette ◽  
Teresa L. Longin ◽  
Richard D. Noble ◽  
Carl A. Koval
2002 ◽  
Vol 21 (1) ◽  
pp. 139-151 ◽  
Author(s):  
Peter J. Vander Nat ◽  
William W. Keep

A specific form of direct selling, multilevel marketing (MLM), experienced significant international growth during the 1990s, facilitated in part by the development of the Internet. A corresponding increase in the investigation and prosecution of illegal pyramid schemes occurred during the same period. These parallel activities led to increased uncertainty among marketing managers who used or wished to use the MLM approach. The authors examine similarities between the multilevel approach to marketing and activities associated with illegal pyramid schemes. A mathematical model is used to differentiate between the two on the basis of previous pyramid scheme cases and current U.S. law. The results of the model suggest key factors that marketers interested in MLM will need to consider when developing this type of distribution channel.


2021 ◽  
pp. 107815522199284
Author(s):  
Ana C Riestra ◽  
Carmen López-Cabezas ◽  
Marion Jobard ◽  
Mertxe Campo ◽  
María J Tamés ◽  
...  

Introduction The aim of this study is to compare productivity of the KIRO Oncology compounding robot in three hospital pharmacy departments and identify the key factors to predict and optimize automatic compounding time. Methods The study was conducted in three hospitals. Each hospital compounding workload and workflow were analyzed. Data from the robotic compounding cycles from August 2017 to July 2018 were retrospectively obtained. Nine cycle specific parameters and five productivity indicators were analysed in each site. One-to-one differences between hospitals were evaluated. Next, a correlation analysis between cycle specific factors and productivity indicators was conducted; the factors presenting a highest correlation to automatic compounding time were used to develop a multiple regression model (afterwards validated) to predict the automatic compounding time. Results A total of 2795 cycles (16367 preparations) were analysed. Automatic compounding time showed a relevant positive correlation (ǀrs|>0.40) with the number of preparations, number of vials and total volume per cycle. Therefore, these cycle specific parameters were chosen as independent variables for the mathematical model. Considering cycles lasting 40 minutes or less, predictability of the model was high for all three hospitals (R2:0.81; 0.79; 0.72). Conclusion Workflow differences have a remarkable incidence in the global productivity of the automated process. Total volume dosed for all preparations in a cycle is one of the variables with greater influence in automatic compounding time. Algorithms to predict automatic compounding time can be useful to help users in order to plan the cycles launched in KIRO Oncology.


Author(s):  
Valery KURGANOV ◽  
Mikhail GRYAZNOV ◽  
Egor TIMOFEEV ◽  
Liliya POLYAKOVA

The results of this study on the loss of live poultry at various stages of delivery from the farm to the processing plant by road are given. A factor analysis of the reasons for the loss of livestock delivered from the farm to the processing plant was carried out. The dependencies of livestock losses on loading delays and the duration of the movement of the loaded poultry farm to the processing plant were established. Methodological recommendations for rationing the number of injuries observed during delivery were developed. The study of losses of live birds during delivery to the processing plant from the density of stocking in shipping boxes was carried out; the economic and mathematical model for optimizing the landing of live birds in shipping boxes was proposed. The calculation of the economic impact of the implementation of the results of the study is given.


2020 ◽  
pp. 55-57
Author(s):  
M.G. Galkin ◽  
A.S. Smagin ◽  
A.S. Pupyireva

An algorithm for the development of a mathematical model of cutting processing, as a multifactorial process, which determines the influence of significant parameters of the cutting mode on the roughness of the processed surface, is proposed. In the development of the algorithm, the method of extreme experimental design is used. Keywords cutting, mode, manufacturing process, surface roughness, mathematical model. [email protected]


1977 ◽  
Vol 14 (3) ◽  
pp. 189-212 ◽  
Author(s):  
John W. Cotton ◽  
John P. Gallagher ◽  
Sandra P. Marshall

The definition of hierarchical structure is reviewed, together with psychometric and experimental evidence regarding the existence of specific structures. Exceptions to hierarchical ordering are frequent enough to merit consideration of an assumption that skill on an item may simply transfer to the next higher item rather than being fully prerequisite to it. In some cases an alternate route hierarchy may occur, with persons either learning an item and then the next item or learning both at the same time. A mathematical model including hierarchical and nonhierarchical options fir a two-component task is presented; an experimental design appropriate to testing the model and related transfer hypotheses is also presented.


2022 ◽  
Author(s):  
Xavier Moreau ◽  
Magalie Claeys-Bruno ◽  
Jean-Pascal Andraud ◽  
Hervé Macarie ◽  
Daniel E Martínez ◽  
...  

Abstract Chlordecone (CLD), an obsolete insecticide, used in the French West Indies between 1972 and 1993, is persistent in the environment but can be dechlorinated either chemically or under the action of microorganisms. Therefore, if soil remediation programs based on these processes are implemented in areas still contaminated today, those will see their concentrations of dechlorinated derivatives increase and these compounds will be also found in freshwater by streaming, leaching and erosion processes. The purpose of the present study was to evaluate, at environmental concentrations, the toxic effects of mixtures of chlordecone and a three-chlorine substituted byproduct. A hydra clone, which has been confirmed to be Hydra vulgaris Pallas, 1766 has been retained for bioassays where the toxicity has been evaluated by regeneration capacity during exposure. Exposure to mixtures is complex to investigate by classical methods, therefore, an experimental design associated to a mathematical model has been used to predict the effects of all the mixtures and to detect the toxic influence of each compound. The predictive model is discussed regarding the stochastic “endocrine disruptor effect” of CLD. At probable environmental concentrations of the compounds in the mixture, results show that impairment of regeneration capacity is explained mostly by the presence of CLD in the mixtures and support the implementation of remediation programs aimed at dechlorination of this persistent organochlorine pesticide.


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Peng Wang ◽  
Jingcai Li ◽  
Lin Han

Tool design is one of the key factors that restrict the development of gear skiving technology since the design principle does not correspond to the cutting principle. The existing skiving tool cannot achieve ideal machining accuracy and reasonable cutting angles. In view of this, some research has been done in this paper. Firstly, the skiving principle is investigated essentially according to the skiving motions. Then, the principle of tool design is analyzed based on the theory of conjugate surface, and a new tool design method is proposed to match the skiving principle. For this, all the skiving patterns for various kinds of workpieces are enumerated and summarized to abstract a normalized skiving model. Based on this, the mathematical model of the conjugate surface is then derived to lay the foundation for tool design. Then, the design methods of cutting edge, rake face, and flank face are proposed. An example is presented at last, and the cutting simulation is conducted. The result proves that the proposed methods are correct and valid. The theoretical research in this paper could promote the improvement of skiving tools.


Author(s):  
Chiao Yi Yang ◽  
Frederick Kin Hing Phoa ◽  
Yen-Sheng Chiang

Transitivity is one of the most important mechanisms to form a social network in a human society, but it remains unclear how such behavior is quantified and affected by some key factors, including the social environment and the participants' characters. This study investigates the sharing behavior based on the notion of transitivity and an experiment is conducted on a variety of populations from kindergarteners to teenagers. The key effects that have high impacts to the sharing behavior are identified from the statistical analysis of the experimental results. A mathematical model is built for the experimental results and its performance compared with other models is also illustrated.


Author(s):  
Fa Zhang ◽  
Shi-Hui Wu ◽  
Zhi-Hua Song

Multi-agent based simulation (MABS) is an important approach for studying complex systems. The Agent-based model often contains many parameters, these parameters are usually not independent, with differences in their range, and may be subjected to constraints. How to use MABS investigating complex systems effectively is still a challenge. The common tasks of MABS include: summarizing the macroscopic patterns of the system, identifying key factors, establishing a meta-model, and optimization. We proposed a framework of experimental design and data mining for MABS. In the framework, method of experimental design is used to generate experiment points in the parameter space, then generate simulation data, and finally using data mining techniques to analyze data. With this framework, we could explore and analyze complex system iteratively. Using central composite discrepancy (CCD) as measure of uniformity, we designed an algorithm of experimental design in which parameters could meet any constraints. We discussed the relationship between tasks of complex system simulation and data mining, such as using cluster analysis to classify the macro patterns of the system, and using CART, PCA, ICA and other dimensionality reduction methods to identify key factors, using linear regression, stepwise regression, SVM, neural network, etc. to build the meta-model of the system. This framework integrates MABS with experimental design and data mining to provide a reference for complex system exploration and analysis.


Author(s):  
Deshun Sun ◽  
Li Duan ◽  
Jianyi Xiong ◽  
Daping Wang

Abstract To forecast the spread tendency of the COVID-19 in China and provide effective strategies to prevent the disease, an improved SEIR model was established. Parameters of our model were estimated based on collected data that issued by the National Health Commission of China (NHCC) from January 10 to March 3. The model was used to forecast the spread tendency of the disease. The key factors influencing the epidemic were explored through modulation of parameters, including the removal rate, the average number of the infected contacting the susceptible per day and the average number of the exposed contacting the susceptible per day. The correlation of the infected is 99.9% between established model data in this study and issued data by NHCC from January 10 to February 15. The correlation of the removed is 99.8%. The average forecasting error rates of the infected and the removed are 0.78% and 0.75%, respectively, from February 16 to March 3. The peak time of the epidemic forecast by our established model coincided with the issued data by NHCC. Therefore, our study established a mathematical model with high accuracy. The aforementioned parameters significantly affected the trend of epidemic, suggesting that the exposed and the infected population should be strictly isolated. If the removal rate increases to 0.12, the epidemic will come to an end on May 25. In conclusion, the proposed mathematical model accurately forecast the spread tendency of COVID-19 in China and the model can be applied for other countries with appropriate modifications.


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