Research on Joint Optimization of Level of Repair Analysis and Spare Parts Stocks

2014 ◽  
Vol 668-669 ◽  
pp. 1633-1636
Author(s):  
Li Xu ◽  
Qing Min Li ◽  
Hua Li
Keyword(s):  
Optimization Method ◽  
Spare Parts ◽  
Joint Optimization ◽  
Variable Cost ◽  
Fixed Cost ◽  
Invasive Weed ◽  
Equipment Availability ◽  
Investment Cost ◽  
Level Of Repair Analysis ◽  
Margin Analysis

According to the real background of repair and supply of spare parts, aims to reasonably plan that how to and where to repair the failure parts, where to deploy the repair resources and develop the initial spares configuration program such that the availability target of equipment is achieved with the lowest investment cost, the joint optimization model for level of repair analysis (LORA) and spare parts stocks is established consisting of variable cost and fixed cost that produced in maintenance as well as the equipment availability, and a new joint optimization method for the model is proposed combined Invasive Weed optimization (IWO) and margin analysis, then the optimization is realized. In a given example, the optimization result is gotten, through which the validity of the model and method is proved.

scholarly journals Joint Optimization Method of Spare Parts Stocks and Level of Repair Analysis Considering the Multiple Failure Modes

2021 ◽  
Vol 11 (16) ◽  
pp. 7254
Author(s):  
Ruiqi Wang ◽  
Guangyu Chen ◽  
Jie Wu ◽  
Wei Zhou ◽  
Zheng Huang
Keyword(s):  
Optimization Model ◽  
Failure Modes ◽  
Optimization Method ◽  
Spare Parts ◽  
Joint Optimization ◽  
Multiple Failure Modes ◽  
System Availability ◽  
Spare Parts Inventory ◽  
Maintenance Decisions ◽  
Level Of Repair Analysis

For the repair level and spare parts stocking problems, generally METRIC type methods and Level of repair analysis (LORA) are used separately. Since LORA does not consider the availability of capital goods, solving LORA and spare parts stocking problems sequentially may lead to suboptimal solutions. On these considerations, this study presents a joint optimization method to minimize the service logistics cost under the constraints of system availability. Maintenance capability factor and maintenance decisions are introduced into the joint optimization model to express the influence of multiple failure modes on repair level and spare parts stocking. Thus, we establish the bridge relationship between LORA and METRIC models. The joint optimization model is solved by an improved iterative algorithm, and a typical fleet system is taken as an example to verify the correctness and effectiveness of the model and the algorithm. Compared with the optimization of spare parts inventory and maintenance level independently, the joint optimization method could effectively reduce the service logistic system cost.

scholarly journals Joint optimization of level of repair analysis and spare parts stocks

2012 ◽  
Vol 222 (3) ◽  
pp. 474-483 ◽  
Author(s):  
R.J.I. Basten ◽  
M.C. van der Heijden ◽  
J.M.J. Schutten
Keyword(s):  
Spare Parts ◽  
Joint Optimization ◽  
Level Of Repair Analysis

EDITORIAL: Migration and competitiveness: Japan and the United States

2013 ◽  
Vol 10 (2) ◽  
pp. 115-124
Author(s):  
Philip L. Martin
Keyword(s):  
United States ◽  
The United States ◽  
Variable Cost ◽  
Fixed Cost ◽  
Special Issue ◽  
Science And Engineering ◽  
The Past ◽  
Past Half Century ◽  
Key Sectors ◽  
Past Half

Japan and the United States, the world’s largest economies for most of the past half century, have very different immigration policies. Japan is the G7 economy most closed to immigrants, while the United States is the large economy most open to immigrants. Both Japan and the United States are debating how immigrants are and can con-tribute to the competitiveness of their economies in the 21st centuries. The papers in this special issue review the employment of and impacts of immigrants in some of the key sectors of the Japanese and US economies, including agriculture, health care, science and engineering, and construction and manufacturing. For example, in Japanese agriculture migrant trainees are a fixed cost to farmers during the three years they are in Japan, while US farmers who hire mostly unauthorized migrants hire and lay off workers as needed, making labour a variable cost.

scholarly journals Marketing and Socioeconomics Aspects of Large Cardamom Production in Tehrathum, Nepal

2018 ◽  
Vol 4 ◽  
pp. 79-85
Author(s):  
Nirajan Bhandari ◽  
Thaneshwar Bhandari
Keyword(s):  
Farmyard Manure ◽  
Variable Cost ◽  
Fixed Cost ◽  
Selling Price ◽  
Farmers Market ◽  
The Status ◽  
Production Area ◽  
Benefit Cost ◽  
Agriculture Development ◽  
Large Cardamom

A survey was conducted in November 2015 in one of the pocket area of large cardamom production in Teharthum District, eastern Nepal with aim to investigate the status of cardamom enterprises. The parameters used were cardamom production area, type of manure used, drying facilities, technical skills of farmers, market channels and variable cost etc. We purposively selected 30 cardamom producers and stakeholders for interview pre-designed questionnaires. The result showed that average area, production and productivity of large cardamom per household were 0.86 ha, 200 kg and 232 kg.ha-1, respectively, with the average farming experience of 22 years. It was revealed that 13% farmers used farmyard organic manure, the use of 1.5 kg/plant farmyard manure might produce 28.5% higher yield cardamom compared to without using any manure or fertilizers. It was also revealed among the responded only 7% had received improved drying machine from District Agriculture Development Office (DADO) at 50% subsidy, while only 23% of farmers received training and technical services from DADO. The study showed that per hectare average total cost of large cardamom production, selling price and gross revenue were NRs. 2,36,705 ($2255), NRs. 5,50,305 ($5240) and NRs. 3,13,600 ($2985), respectively, with benefit/cost (B/C) ratio of 2 after the completion of gestation period of 4 years. Our survey showed that predominant marketing approach was by direct sell to the traders located at district headquarter. The productivity of large cardamom was influenced by various factors, such as nearly 75.2% of the variation in productivity was explained by the number of active family members, farming period, area, intercultural operations, variable cost and depreciated fixed cost.

Hybrid Elman Neural Network and an Invasive Weed Optimization Method for Bridge Defect Recognition

2020 ◽  
pp. 036119812096794
Author(s):  
Eslam Mohammed Abdelkader ◽  
Osama Moselhi ◽  
Mohamed Marzouk ◽  
Tarek Zayed
Keyword(s):  
Neural Network ◽  
Prediction Models ◽  
Statistical Significance ◽  
Optimization Method ◽  
Bridge Management ◽  
Invasive Weed Optimization ◽  
Invasive Weed ◽  
Elman Neural Network ◽  
Existing Bridges ◽  
Value Decomposition

Existing bridges are aging and deteriorating, raising concerns for public safety and the preservation of these valuable assets. Furthermore, the transportation networks that manage many bridges face budgetary constraints. This state of affairs necessitates the development of a computer vision-based method to alleviate shortcomings in visual inspection-based methods. In this context, the present study proposes a three-tier method for the automated detection and recognition of bridge defects. In the first tier, singular value decomposition ([Formula: see text]) is adopted to formulate the feature vector set through mapping the most dominant spatial domain features in images. The second tier encompasses a hybridization of the Elman neural network ([Formula: see text]) and the invasive weed optimization (I[Formula: see text]) algorithm to enhance the prediction performance of the ENN. This is accomplished by designing a variable optimization mechanism that aims at searching for the optimum exploration–exploitation trade-off in the neural network. The third tier involves validation through comparisons against a set of conventional machine-learning and deep-learning models capitalizing on performance prediction and statistical significance tests. A computerized platform was programmed in C#.net to facilitate implementation by the users. It was found that the method developed outperformed other prediction models achieving overall accuracy, F-measure, Kappa coefficient, balanced accuracy, Matthews’s correlation coefficient, and area under curve of 0.955, 0.955, 0.914, 0.965, 0.937, and 0.904, respectively as per cross validation. It is expected that the method developed can improve the decision-making process in bridge management systems.

scholarly journals Economics analysis of Seed Yam production in Aeroponic system

2020 ◽  
Vol 56 (2) ◽  
Author(s):  
Patricia Pinamang Acheampong ◽  
Marian Dorcas Quain ◽  
David Appiah-Kubi ◽  
Jonas Osei-Adu ◽  
Stella Ama Ennin ◽  
...  
Keyword(s):  
Tissue Culture ◽  
Private Sector ◽  
Production Costs ◽  
Variable Cost ◽  
Fixed Cost ◽  
Cost Ratio ◽  
Total Cost ◽  
Benefit Cost Ratio ◽  
Short Period ◽  
Using Data

The supply of seed yams for intensive yam production is hindered by many constraints, including diseases and pest infestations as well as the unavailability of quality planting material. The combination of tissue culture and aeroponics system is perceived to be the way towards clean and adequate supply of seed yam for enhanced yam production. However, the system is considered as expensive for any individual to implement. In order to encourage private sector to participate in this venture, the economic analysis determining the feasibility and viability of using aeroponics in seed yam production was performed. Using data from established tissue culture and aeroponics system in Ghana, the fixed cost and variable cost parameters as well as production costs were obtained. Results revealed that total cost of building aeroponics structure amounted to GH₵ 94,178.00 (USD 17,938.70). Annual cost of aeroponics structure was GH₵ 9,417.82 (USD 1,793.87). Annual total cost of production totalled GH₵ 204,391.75 (USD 38,931.61). Annual net revenue was GH₵ 75,888.00 (USD 14,454.86). Payback period was 15 months and benefit cost ratio was 1.4. Aeroponics system for seed yam production is therefore profitable since short period would be needed to recoup investment. For food security and creation of workplaces, government could partner with the private sector in the establishment of aeroponics systems to increase yam production and export.

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