scholarly journals Effect of Time-Varying Factors on Optimal Combination of Quality Inspectors for Offline Inspection Station

Mathematics ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 51 ◽  
Author(s):  
Muhammad Babar Ramzan ◽  
Shehreyar Mohsin Qureshi ◽  
Sonia Irshad Mari ◽  
Muhammad Saad Memon ◽  
Mandeep Mittal ◽  
...  

With advanced manufacturing technology, organizations like to cut their operational cost and improve product quality, yet the importance of human labor is still alive in some manufacturing industries. The performance of human-based systems depends much on the skill of labor that varies person to person within available manpower. Much work has been done on human resource and management, however, allocation of manpower based on their skill yet not investigated. For this purpose, this study considered offline inspection system where inspection is performed by the human labor of varying skill levels. A multi-objective optimization model is proposed based on Time-Varying factors; inspection skill, operation time and learning behavior. Min-max goal programming technique was used to determine the efficient combination of inspectors of each skill level at different time intervals of a running order. The optimized results ensured the achievement of all objectives of inspection station: the cost associated with inspectors, outgoing quality and inspected quantity. The obtained results proved that inspection performance of inspectors improves significantly with learning and revision of allocation of inspectors with the proposed model ensure better utilization of available manpower, maintain good quality and reduce cost as well.

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Yingchao You ◽  
Guijiang Duan ◽  
Rui Liu ◽  
Taotao Liu ◽  
Mingcong Huang

With the development of smart manufacturing, quality has become an indispensable issue in the manufacturing process. Although there is increasing publication about inspection allocation problems, inspection allocation optimization research considering resource capability is scarce. This paper focuses on the inspection allocation problem with resource constraints in the flexible manufacturing system. Combined with the inspection resource capability model, a bi-objective model is developed to minimize the cost and balance loads of the inspection station. A modified NSGA-II algorithm with adaptive mutation operators is suggested to deal with the proposed model. Finally, a simulation experiment is conducted to test the performance of the modified algorithm and the results demonstrate that modified NSGA-II can obtain acceptable inspection solutions.


2015 ◽  
Vol 33 (6) ◽  
pp. 517-529 ◽  
Author(s):  
Nigokhos Krikorov Kanaryan ◽  
Peter Chuknyisky ◽  
Violeta Kasarova

Purpose – The International Valuations Standards Committee adopts the Capital Asset Pricing Model as a method for estimation of the cost of equity. It has several drawbacks and appraisers in emerging markets need more useful model for cost of equity estimation. The paper aims to discuss these issues. Design/methodology/approach – The proposed model is a modification of the Salomon Smith Barney model for cost of capital determination. The econometric part of the model incorporates the non-synchronous effect, the thin trading effect, the time varying risk nature, and the systematic country risk. Findings – The model estimates the cost of equity of Bulgarian REITs more accurate than the one, who uses the traditional β estimation. Practical implications – The study provides appraisers, business consultants, and investment bankers with a consistent model for cost of equity estimation. The model incorporates most of the features of emerging markets REITs return series and avoids the weaknesses of the single-factor model for cost of equity estimation in emerging markets. Originality/value – The proposed model reflects the following characteristics: the degree of diversification of the particular investor (imperfectly diversified); country risk; and time-varying risk nature. The political risk is incorporated by more objective measure of the systematic country risk.


Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1213
Author(s):  
Ahmed Aljanad ◽  
Nadia M. L. Tan ◽  
Vassilios G. Agelidis ◽  
Hussain Shareef

Hourly global solar irradiance (GSR) data are required for sizing, planning, and modeling of solar photovoltaic farms. However, operating and controlling such farms exposed to varying environmental conditions, such as fast passing clouds, necessitates GSR data to be available for very short time intervals. Classical backpropagation neural networks do not perform satisfactorily when predicting parameters within short intervals. This paper proposes a hybrid backpropagation neural networks based on particle swarm optimization. The particle swarm algorithm is used as an optimization algorithm within the backpropagation neural networks to optimize the number of hidden layers and neurons used and its learning rate. The proposed model can be used as a reliable model in predicting changes in the solar irradiance during short time interval in tropical regions such as Malaysia and other regions. Actual global solar irradiance data of 5-s and 1-min intervals, recorded by weather stations, are applied to train and test the proposed algorithm. Moreover, to ensure the adaptability and robustness of the proposed technique, two different cases are evaluated using 1-day and 3-days profiles, for two different time intervals of 1-min and 5-s each. A set of statistical error indices have been introduced to evaluate the performance of the proposed algorithm. From the results obtained, the 3-days profile’s performance evaluation of the BPNN-PSO are 1.7078 of RMSE, 0.7537 of MAE, 0.0292 of MSE, and 31.4348 of MAPE (%), at 5-s time interval, where the obtained results of 1-min interval are 0.6566 of RMSE, 0.2754 of MAE, 0.0043 of MSE, and 1.4732 of MAPE (%). The results revealed that proposed model outperformed the standalone backpropagation neural networks method in predicting global solar irradiance values for extremely short-time intervals. In addition to that, the proposed model exhibited high level of predictability compared to other existing models.


2016 ◽  
Vol 10 (10) ◽  
pp. 133
Author(s):  
Mohammad Ali Nasiri Khalili ◽  
Mostafa Kafaei Razavi ◽  
Morteza Kafaee Razavi

Items supplies planning of a logistic system is one of the major issue in operations research. In this article the aim is to determine how much of each item per month from each supplier logistics system requirements must be provided. To do this, a novel multi objective mixed integer programming mathematical model is offered for the first time. Since in logistics system, delivery on time is very important, the first objective is minimization of time in delivery on time costs (including lack and maintenance costs) and the cost of purchasing logistics system. The second objective function is minimization of the transportation supplier costs. Solving the mathematical model shows how to use the Multiple Objective Decision Making (MODM) can provide the ensuring policy and transportation logistics needed items. This model is solved with CPLEX and computational results show the effectiveness of the proposed model.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Kai Chang

Under departures from the cost-of-carry theory, traded spot prices and conditional volatility disturbed from futures market have significant impacts on futures price of emissions allowances, and then we propose time-varying hedge ratios and hedging effectiveness estimation using ECM-GARCH model. Our empirical results show that conditional variance, conditional covariance, and their correlation between between spot and futures prices exhibit time-varying trends. Conditional volatility of spot prices, conditional volatility disturbed from futures market, and conditional correlation of market noises implied from spot and futures markets have significant effects on time-varying hedge ratios and hedging effectiveness. In the immature emissions allowances market, market participants optimize portfolio sizes between spot and futures assets using historical market information and then achieve higher risk reduction of assets portfolio revenues; accordingly, we can obtain better hedging effectiveness through time-varying hedge ratios with departures from the cost-of-carry theory.


2021 ◽  
Vol 2021 (23) ◽  
pp. 31-42
Author(s):  
Anatolii Tsynka ◽  
◽  
Andrii Hrinchuk ◽  
Ivan Rakovych ◽  
◽  
...  

Introduction. In the modern conditions of the pricing system in the construction of Ukraine, the key value have the estimated norms, which are presented in separate collections, the main purpose of which is to determine the standard quantity of resources required to perform a particular type of work as a basis for the transition to the cost indicators. In order to determine the cost of road work objectively and accurately, it is essential that the indicators of estimated norms meet the requirements of regulatory documents and modern methods of execution of road works.Problematics. In connection with the active improvement of the regulatory base of the road construction industry, permanent upgrade of road organizations technique fleet, the introduction of new technologies and materials in construction and operation of roads, improving the methods of work there is a discrepancy between the existing resource element of estimated norms and the actual conditions of work in terms of built-up labor costs, the operation time of machines and mechanisms and the range of materials. Accordingly, it affects the reliability and accuracy of determining the cost of road works.Purpose. Improvement and harmonization with actual working conditions and requirements of regulatory documents of industry regulatory and estimate base of resource elementary estimated norms for work performed during construction, reconstruction, repair and operational maintenance of roads and bridges to ensure reliable and valid technical, economic and estimated calculations.Materials and methods. During work performance the analysis of the regulatory documentation, establishing the requirements to the technology of road works and materials has been carried out. A number of chronometric observations with the measurement of time of road works in full-scale conditions was carried out. The obtained data were summarized, averaged and on their basis the indicators of the resource element of the estimated norms were estimated.Results. A review of the main amendments and additions, which came into force after the approval of Amendment No 2 SOU 42.1-37641918-035:2018 [1] and Amendment No 2 SOU 42.1-37641918-071:2018 [2], which were developed to improve the regulatory-estimate base for the calculation of road works, taking into account the requirements and provisions of existing regulatory documents taking into account the current state of scientific and technological progress in the road sector.Conclusions. The above analysis of the amendments that came into force with the approval of [1]. and [2] will systematize the innovations provided by the requirements of current regulatory documents on the calculation of the cost of road works and the development of relevant documents at all stages of the investment process, planning and organization of road works, as well as the writing-off of material resources. Review and systematization of recent improvements in the estimated regulatory documents for road works will provide an opportunity to optimally plan the use of available material, labor and financial resources, often limited.Keywords: public road, operational maintenance, investment documentation, overhaul and current repairs, machine, mechanism, regulatory document, resource element estimate norm, Standard of Organization of Ukraine.


BIOMATH ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 2106147
Author(s):  
Debkumar Pal ◽  
D Ghosh ◽  
P K Santra ◽  
G S Mahapatra

This paper presents the current situation and how to minimize its effect in India through a mathematical model of infectious Coronavirus disease (COVID-19). This model consists of six compartments to population classes consisting of susceptible, exposed, home quarantined, government quarantined, infected individuals in treatment, and recovered class. The basic reproduction number is calculated, and the stabilities of the proposed model at the disease-free equilibrium and endemic equilibrium are observed. The next crucial treatment control of the Covid-19 epidemic model is presented in India's situation. An objective function is considered by incorporating the optimal infected individuals and the cost of necessary treatment. Finally, optimal control is achieved that minimizes our anticipated objective function. Numerical observations are presented utilizing MATLAB software to demonstrate the consistency of present-day representation from a realistic standpoint.


2018 ◽  
Vol 13 (3) ◽  
pp. 244
Author(s):  
Laura Broccardo ◽  
Luisa Tibiletti ◽  
Pertti Vilpas

This study investigates how balancing internal and external financing sources can create economic value. We set a financial scorecard, consisting of the Cost of Debt (COD), Return on Investment (ROI), and the Cost of Equity (COE). We show that COE should be a cap for COD and a floor for ROI in order to increase the Net Present Value at Weighted Average Cost of Capital and the Adjusted Present Value of the levered investment. However, leverage should be carefully monitored if COD and ROI go off the grid. Situations where leverage has the opposite effect on value creation and the Equity Internal Rate of Return are also discussed. Illustrative examples are given. The proposed model aims to help corporate management in financial decisions.


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