The purpose of this research was to develop a new approach in determination of overhaul and maintenance cost of loading equipment in surface mining. Two statistical models including univariate exponential regression (...The purpose of this research was to develop a new approach in determination of overhaul and maintenance cost of loading equipment in surface mining. Two statistical models including univariate exponential regression (UER) and multivariate linear regression (MLR) were used in this study. Loading equipment parameters such as bucket capacity, machine weight, engine power, boom length, digging depth, and dumping height were considered as variables. The results obtained by models and mean absolute error rate indicate that these models can be applied as the useful tool in determination of overhaul and maintenance cost of loading equipment. The results of this study can be used by the decision-makers for the specific surface mining operations.展开更多
The motivation for cost-effective management of highway pavements is evidenced not only by the massive expenditures associated with these activities at a national level but also by the consequences of poor pavement co...The motivation for cost-effective management of highway pavements is evidenced not only by the massive expenditures associated with these activities at a national level but also by the consequences of poor pavement condition on road users.This paper presents a state-of-the-art review of multi-objective optimization(MOO)problems that have been formulated and solution techniques that have been used in selecting and scheduling highway pavement rehabilitation and maintenance activities.First,the paper presents a taxonomy and hierarchy for these activities,the role of funding sources,and levels of jurisdiction.The paper then describes how three different decision mechanisms have been used in past research and practice for project selection and scheduling(historical practices,expert opinion,and explicit mathematical optimization)and identifies the pros and cons of each mechanism.The paper then focuses on the optimization mechanism and presents the types of optimization problems,formulations,and objectives that have been used in the literature.Next,the paper examines various solution algorithms and discusses issues related to their implementation.Finally,the paper identifies some barriers to implementing multi-objective optimization in selecting and scheduling highway pavement rehabilitation and maintenance activities,and makes recommendations to overcome some of these barriers.展开更多
Aircraft on ground or down-time for its maintenance is a clear loss in revenue for an airline operation. With never ending competition and growing operating costs of aircraft, airlines continuously need to explore opp...Aircraft on ground or down-time for its maintenance is a clear loss in revenue for an airline operation. With never ending competition and growing operating costs of aircraft, airlines continuously need to explore opportunities to reduce the aircraft down-time in order to remain sustainable. Due to round the clock operation feature of scheduled airlines, aircraft maintenance operations are generally carried out using traditional management methodologies instead of considering it as a project. Though aircraft heavy maintenance checks consist of several major tasks that can last from few weeks to a year, the maintenance organisations do not adopt modern project management methodologies. Therefore, this paper models a heavy maintenance check of an Airbus aircraft as a typical project and adopts contemporary project management methodology to explore the possibility of reducing the downtime. To this end, a case study has been done at an aircraft maintenance company to analyse the potential of this project management method in aircraft maintenance industry.展开更多
Petty maintenance projects cost lowly relative to other projects, project time limit is short. The characteristics such as form much shape also have particularity for its audit. This paper the existent actual conditio...Petty maintenance projects cost lowly relative to other projects, project time limit is short. The characteristics such as form much shape also have particularity for its audit. This paper the existent actual condition in scattered project settlement combination own working experience, put forward some methods for petty maintenance project audit.展开更多
PBMC(performance-based maintenance contracts)provides incentives and/or disincentives to the contractor to achieve desired outcomes or results.In other words,the concept of PBMC is to pay a contractor based on the act...PBMC(performance-based maintenance contracts)provides incentives and/or disincentives to the contractor to achieve desired outcomes or results.In other words,the concept of PBMC is to pay a contractor based on the actual results(performance or LOS(level of service)),not on the performed work.PBMC does not detail to the contractor how,when,or where to do the work.Instead,it specifies performance standards or targets for measurable outcomes and sometimes outputs.There are several benefits from implementing PBMC.Higher LOS,i.e.,better quality,potential reduction in agency costs and downsized maintenance workforce are among these benefits.Also,there are several challenges facing the implementation of PBMC.One of the most complex challenges that relates to both the agency and contractor,and in some cases to the public,is how to manage LOS in an objective manner and to demonstrate that policy goals and objectives regarding quality of life expectancy are achieved without any increase in the LCC(life cycle cost)of the assets.This challenge,along with many other challenges,can be addressed through the adoption of an AM(asset management)approach.AM approach facilitates the long-term planning based on the current and future conditions and desired LOS.In addition,AM provides the necessary tools to objectively monitor LOS,and hence the contractor performance,which will contribute to the success of the implementation of PBMC.展开更多
文摘The purpose of this research was to develop a new approach in determination of overhaul and maintenance cost of loading equipment in surface mining. Two statistical models including univariate exponential regression (UER) and multivariate linear regression (MLR) were used in this study. Loading equipment parameters such as bucket capacity, machine weight, engine power, boom length, digging depth, and dumping height were considered as variables. The results obtained by models and mean absolute error rate indicate that these models can be applied as the useful tool in determination of overhaul and maintenance cost of loading equipment. The results of this study can be used by the decision-makers for the specific surface mining operations.
基金This work is supported by the Next Generation Transportation Systems Center(NEXTRANS),USDOT's Region 5 University Transportation CenterThe work is also affiliated with Purdue University College of Engineering's Institute for Control,Optimization,and Networks(ICON)and Center for Intelligent Infrastructure(CII)initiatives.
文摘The motivation for cost-effective management of highway pavements is evidenced not only by the massive expenditures associated with these activities at a national level but also by the consequences of poor pavement condition on road users.This paper presents a state-of-the-art review of multi-objective optimization(MOO)problems that have been formulated and solution techniques that have been used in selecting and scheduling highway pavement rehabilitation and maintenance activities.First,the paper presents a taxonomy and hierarchy for these activities,the role of funding sources,and levels of jurisdiction.The paper then describes how three different decision mechanisms have been used in past research and practice for project selection and scheduling(historical practices,expert opinion,and explicit mathematical optimization)and identifies the pros and cons of each mechanism.The paper then focuses on the optimization mechanism and presents the types of optimization problems,formulations,and objectives that have been used in the literature.Next,the paper examines various solution algorithms and discusses issues related to their implementation.Finally,the paper identifies some barriers to implementing multi-objective optimization in selecting and scheduling highway pavement rehabilitation and maintenance activities,and makes recommendations to overcome some of these barriers.
文摘Aircraft on ground or down-time for its maintenance is a clear loss in revenue for an airline operation. With never ending competition and growing operating costs of aircraft, airlines continuously need to explore opportunities to reduce the aircraft down-time in order to remain sustainable. Due to round the clock operation feature of scheduled airlines, aircraft maintenance operations are generally carried out using traditional management methodologies instead of considering it as a project. Though aircraft heavy maintenance checks consist of several major tasks that can last from few weeks to a year, the maintenance organisations do not adopt modern project management methodologies. Therefore, this paper models a heavy maintenance check of an Airbus aircraft as a typical project and adopts contemporary project management methodology to explore the possibility of reducing the downtime. To this end, a case study has been done at an aircraft maintenance company to analyse the potential of this project management method in aircraft maintenance industry.
文摘Petty maintenance projects cost lowly relative to other projects, project time limit is short. The characteristics such as form much shape also have particularity for its audit. This paper the existent actual condition in scattered project settlement combination own working experience, put forward some methods for petty maintenance project audit.
文摘PBMC(performance-based maintenance contracts)provides incentives and/or disincentives to the contractor to achieve desired outcomes or results.In other words,the concept of PBMC is to pay a contractor based on the actual results(performance or LOS(level of service)),not on the performed work.PBMC does not detail to the contractor how,when,or where to do the work.Instead,it specifies performance standards or targets for measurable outcomes and sometimes outputs.There are several benefits from implementing PBMC.Higher LOS,i.e.,better quality,potential reduction in agency costs and downsized maintenance workforce are among these benefits.Also,there are several challenges facing the implementation of PBMC.One of the most complex challenges that relates to both the agency and contractor,and in some cases to the public,is how to manage LOS in an objective manner and to demonstrate that policy goals and objectives regarding quality of life expectancy are achieved without any increase in the LCC(life cycle cost)of the assets.This challenge,along with many other challenges,can be addressed through the adoption of an AM(asset management)approach.AM approach facilitates the long-term planning based on the current and future conditions and desired LOS.In addition,AM provides the necessary tools to objectively monitor LOS,and hence the contractor performance,which will contribute to the success of the implementation of PBMC.