scholarly journals Multi-Echelon Inventory Allocation of Civil Aircraft Spare Parts Considering Maintenance Ratio

2018 ◽  
Vol 36 (3) ◽  
pp. 582-589 ◽  
Author(s):  
Yunwen Feng ◽  
Cheng Lu ◽  
Xiaofeng Xue ◽  
Yuchang Liu
Keyword(s):  
Spare Parts ◽  
Analysis Method ◽  
Marginal Analysis ◽  
Allocation Model ◽  
Inventory Optimization ◽  
Civil Aircraft ◽  
Reasonable Cost ◽  
Inventory Allocation ◽  
The Cost ◽  
The Mathematical Model

A multi-echelon inventory allocation technique with maintenance ratio for civil aircraft spare parts was proposed in this paper. Multi-echelon inventory allocation model was established, which integrates maintenance rate into METRIC (Multi-echelon technique for recoverable item control) model, and then marginal analysis method was applied to solve this model and accomplish multi-echelon inventory allocation of spare parts. Firstly, the theory of multi-echelon inventory allocation model with maintenance ratio was elaborated, and the mathematical model was established with the fleet availability as the optimization objective, the cost and the safeguard probability as the constraints. Secondly, the procedure of solving multi-echelon inventory allocation model considering the influence of maintenance ratio is discussed based on the marginal analysis method. Thirdly, landing gear LRU (Line repairable units) of a typical civil aircraft were selected as the research object, multi-echelon inventory allocation was investigated by considering maintenance ratio. The analysis results show that the minimum safeguard cost and fleet availability are respectively 2759833 dollars and 0.9806, and the number of LRU of multi echelon inventory allocation are obtained under the condition of satisfying the constrained optimization. The feasibility and effectiveness of the developed method are verified by comparing the traditional analysis method. This paper provides guidance for the accurate allocation of multi echelon inventory optimization for maintenance resources on the premise of reasonable cost reduction.

scholarly journals Research on Configuration Optimization of Civil Aircraft Spare Parts with Lateral Transshipments and Maintenance Ratio

2018 ◽  
Vol 36 (6) ◽  
pp. 1059-1068 ◽  
Author(s):  
Yunwen Feng ◽  
Yuchang Liu ◽  
Xiaofeng Xue ◽  
Cheng Lu
Keyword(s):  
Spare Parts ◽  
Inventory Model ◽  
Inventory System ◽  
Marginal Analysis ◽  
Allocation Model ◽  
Total Cost ◽  
Inventory Optimization ◽  
Theoretical Support ◽  
Civil Aircraft ◽  
Inventory Allocation

A research method for multi-echelon inventory allocation of civil aircraft spare parts with lateral transshipments and maintenance ratio is proposed in this paper, and the maintenance rate is considered into the inventory model, aiming at the problem of multi-echelon inventory allocation with lateral transshipments for civil aircraft spare parts. Firstly, the principle of the multi-echelon inventory model with lateral transshipments and maintenance ratio is proposed. Then, by considering the fleet availability and the satisfaction ratio as the constraints, a mathematical model is built with the inventory system total cost as the optimization objective. Secondly, the procedure of solving multi-echelon inventory allocation model considering the influence of lateral transshipments and maintenance ratio is discussed based on the marginal analysis method. Finally, some components of Boeing 737 are selected as the research objects, the multi-echelon inventory allocation is investigated by considering lateral transshipments and maintenance ratio. The analysis results in this paper show the best number of multi echelon inventory allocation, the minimum inventory system total cost and the fleet availability are 1.205 million dollars and 0.9909 respectively. Comparing the traditional inventory model without considering lateral transshipments and maintenance ratio, and the model which only considers the maintenance ratio, the results indicate that the model offered in this paper could reduce the total cost of inventory system significantly, and provides theoretical support and method guidance for the accurate allocation of multi echelon inventory optimization for civil aircraft spare parts.

scholarly journals Combining regional to local restoration goals in the Brazilian Atlantic forest

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Cassia M.G. Lemos ◽  
Pedro R. Andrade ◽  
Ricardo R. Rodrigues ◽  
Leticia Hissa ◽  
Ana P. D. Aguiar
Keyword(s):  
Cost Effectiveness ◽  
Atlantic Forest ◽  
Natural Regeneration ◽  
Regional Level ◽  
Target Area ◽  
Brazilian Atlantic Forest ◽  
Regeneration Potential ◽  
Allocation Model ◽  
Alternative Scenarios ◽  
The Cost

AbstractTo achieve regional and international large-scale restoration goals with minimum costs, several restoration commitments rely on natural regeneration, a passive and inexpensive strategy. However, natural regeneration potential may vary within the landscape, mainly due to its historical context. In this work, we use spatially explicit restoration scenarios to explore how and where, within a given region, multiple restoration commitments could be combined to achieve cost-effectiveness outcomes. Our goal is to facilitate the elaboration of forest restoration plans at the regional level, taking into consideration the costs for active and passive restoration methods. The approach includes (1) a statistical analysis to estimate the natural regeneration potential for a given area based on alternative sets of biophysical, land cover, and/or socioeconomic factors and (2) the use of a land change allocation model to explore the cost-effectiveness of combining multiple restoration commitments in a given area through alternative scenarios. We test our approach in a strategic region in the Brazilian Atlantic Forest Biome, the Paraiba Valley in São Paulo State. Using the available data for 2011, calibrated for 2015, we build alternative scenarios for allocating natural regeneration until 2025. Our models indicate that the natural regeneration potential of the region is actually very low, and the cost-effectiveness outcomes are similar for all scenarios. We believe our approach can be used to support the regional-level decision-making about the implementation of multiple commitments aiming at the same target area. It can also be combined with other approaches for more refined analysis (e.g., optimization models).

scholarly journals An Optimized Mathematical Model for Items Supplies Planning of a Logistic System

2016 ◽  
Vol 10 (10) ◽  
pp. 133
Author(s):  
Mohammad Ali Nasiri Khalili ◽  
Mostafa Kafaei Razavi ◽  
Morteza Kafaee Razavi
Keyword(s):  
Mathematical Model ◽  
Mixed Integer ◽  
Logistics System ◽  
Proposed Model ◽  
Multiple Objective Decision Making ◽  
System Requirements ◽  
Purchasing Logistics ◽  
The Cost ◽  
The Mathematical Model ◽  
First Time

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.

Theoretical and methodological approaches to the calculation of planned costs for maintenance of service vehicles of the road works customer

2021 ◽  
Vol 2021 (23) ◽  
pp. 20-30
Author(s):  
Taras Pechonchyk ◽  
◽  
Vitaliy Ivanchenko ◽  
Keyword(s):  
Customer Service ◽  
Planning Process ◽  
Spare Parts ◽  
Cost Estimates ◽  
The Road ◽  
Fleet Composition ◽  
Cost Planning ◽  
Methodological Approaches ◽  
The Cost ◽  
Service Vehicles

AbstractIntroduction. Effective management of road indstry is particularly important in conditions of limited funding, as it is not possible to provide adequate funding of the economic entity that has the functions of a customer service. The cost of the customer service maintenance depends directly on the compliance with applicable regulations for these works cost determination. One of the aspects that form a considerable part of the costs of customer service is the maintenance of service vehicles.Problem Statement. Road services in the regions (hereinafter RSR) are the recipients and managers of the funds from the State Budget of Ukraine that are directed for the development and maintenance of public roads of state importance, being as well the asset holders of these roads. To perform their functions, the RSR have vehicles on their balance, the use of which involves a number of costs, including fuel and lubricants, repair, maintenance, replacement of tires, etc. The most important of the steps involved in setting the costs of vehicle maintenance is the process of cost planning. Planning has to be based on the structure of the vehicle fleet (own or leased), functional responsibilities and scope of road works.Planning is carried out for vehicles on the balance of the RSR, as well as for leased vehicles. In the case of leasing, the costs mentioned above are added by the vehicles leasing costs. These costs must be forecasted, justified and performed within the approved cost estimates of the customer service expenses.Purpose. The purpose of the article is to highlight the theoretical and methodological approaches to the calculation of planned costs for the maintenance of service vehicles of the road works customer.Materials and methods. Dialectical methods of knowledge, such as analysis and synthesis of fleet composition characteristics and approaches to cost planning methods, as well as induction, were used in writing the article to explore some aspects of the process of calculating the planned cost of maintenance of the road works customer's service vehicles.Results. The study highlights and describes the main approaches to the calculation of planned costs for the maintenance of service vehicles of the road works customer. The methodology of calculation of planned costs for the maintenance of service vehicles is explored.Conclusions. The introduction of a clear methodology and analytical toolkit for calculating all necessary expenditure items for the maintenance of the road works customer's vehicles in the cost planning process will establish the implementation of a clear mechanism for calculating the planned costs of maintenance of the road works customer's vehicles. It will also provide an automated information-analytical complex for planning of cost estimates, with information entry and reporting in standard forms and possibility of prompt response to changes in fleet composition, needs for spare parts, repairs or other expenses for the maintenance of service vehicles and making changes in cost estimates.Keywords: motor vehicles, costs, cost planning, customer service, maintenance of service vehicles

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