Claver Diallo

Verified

Claver verified their affiliation via an institutional email.

Learn more

Verified

Claver verified their affiliation via an institutional email.

Learn more

• PhD, MASc, PEng
• Professor (Full) at Dalhousie University

This paper presents a multi-period multi-objective distributionally robust optimization framework for enhancing the resilience of personal protective equipment (PPE) supply chains against disruptions caused by pandemics. The research is motivated by and addresses the supply chain challenges encountered by a Canadian provincial healthcare provider d...

It is common for sellers to markdown product prices late in a selling season which prompts consumers to strategically manage their purchase timing. Facing consumers' strategic behaviour, the manufacturer should decide the prices for products carefully to ensure its profit. This paper explores the manufacturer's optimal pricing decisions in a closed...

In many settings, fleets of assets must perform series of missions with in-between finite breaks. For such fleets, a widely used maintenance strategy is the fleet selective maintenance (FSM). Under resource constraints, the FSM problem selects an optimal subset of feasible maintenance actions to be performed on a subset of components to minimise th...

This paper offers a novel and significant extension of the Fleet Selective Maintenance Problem (FSMP) by considering asynchronous maintenance breaks and resource-constrained maintenance planning. This constitutes a significant shift from the conventional focus on synchronous breaks for the FSMP formulated to plan maintenance for fleets of mission-c...

Critical network infrastructures such as power grids, telecommunications, and transportation are considered critical for both the development and functioning of modern-day societies. Due to the complexity and interconnectedness of these network infrastructures, potential stress and disaster events can have serious impacts and cause wide-spread disr...

This paper addresses the problem of optimising the spatial and temporal distribution and allocation of vaccines among different groups in an epidemic situation that minimizes the sourcing and shipping costs and epidemiological impacts (e.g., infections or deaths). The problem combines a combinatorial distribution model with a discrete-time, continu...

Rising concerns about sustainability underscore the importance of efficient closed-loop supply chains, especially for energy-intensive materials like glass. Despite being fully recyclable, a significant amount of glass waste ends up in landfills. Recent studies have highlighted the potential of recycled glass as a supplementary cementitious materia...

Maintenance plans for production assets must balance the cost of maintenance against failures/downtime penalties. For marine renewable energy (MRE) generators, this trade-off can be achieved by minimizing the levelized cost of energy (LCOE) which includes operation and maintenance costs. This paper presents a novel optimization model to minimize LC...

Increasing value and complexity in warranty contract design has made warranty policy optimization necessary for manufacturers. This paper investigates a one-dimensional, non-renewing hybrid warranty policy with "as-good-as-new" (AGAN) replacements. The warranty contract spans two periods. AGAN remanufactured secondhand units are used as replacement...

Green hydrogen (GH), produced via electrolysis powered by renewable energy sources (RESs), offers a sustainable energy storage solution. Designing GH production networks is challenging due to the variability introduced by the intermittency of RESs and the reliability of interdependent system components. This study uses optimization to aid GH system...

Vaccines play a crucial role in containing infectious disease outbreaks, as evidenced in the recent COVID-19 pandemic. However, during the early stages of vaccination campaigns, policymakers are often faced with the difficult task of deciding where to distribute the limited available quantities of vaccines and how to allocate them to different popu...

The ability of closed-loop supply chains (CLSC) and reverse logistics (RL) to improve the triple bottom line (economic, social and environmental values) has increased the development of design and management models for CLSCs and RL. Consequently, there exists an extensive body of literature dedicated to exploring these supply and logistics issues....

Recent studies highlight the advantages of integrating production and maintenance planning decisions in manufacturing-distribution systems. Beyond these aspects, it is crucial to consider quality control, ethical sourcing, and decarbonization in the overall decision-making processes. Furthermore, recent advancements in large-scale optimization, rob...

The selective maintenance problem (SMP) arises in many settings where systems perform sequences of missions separated by maintenance breaks. The SMP aims to identify the optimal subset of maintenance actions that will maximize the system reliability for the next mission. This paper addresses the SMP when the durations of the break and maintenance a...

Remanufacturing processes such as refurbishing and reconditioning of used products is one pillar of sustainable manufacturing as, not only, it provides financial opportunities, but also allows manufacturers to engage in sustainable practices. The remanufactured products are typically used as spare parts in maintenance or as replacement products to...

A bidirectional long short-term memory (Bi-LSTM) model is developed to predict a multi-faceted bearing health characteristic using time series vibration measurements from the Case Western Reserve University (CWRU) seeded fault test data. A maximal amount of data is applied with minimal preprocessing to test the model's capabilities and several hype...

Managing uncertainties and risks is always a difficult but fascinating task in fresh fruit supply chains, especially when dealing with the strategy for the production and conveyance of fresh fruit in Vietnam. Following the COVID-19 outbreak, the confluence of economic recession and persistent adverse weather conditions has exacerbated challenges fa...

Maintenance task duration estimations help manage shipyard resource usage and allow planners to decide on maintenance priorities within a limited time frame. Better estimated task durations help produce more robust resource schedules, perform more tasks in facilities such as shipyards, reduce resource idling time and increase ship operational avail...

The fast-food industry currently relies on frozen ingredients to reduce the cost of procurement of raw materials. In recent years, consumers have started to curb their habit of eating out from fast-food chain restaurants due to the growing concerns for unhealthy menu choices made primarily from highly processed and/or frozen food ingredients. To ad...

Selective maintenance is a crucial condition-based strategy for maintaining system reliability over a specific mission length while utilizing optimal resources such as manpower, cost, and time. Achieving an optimal strategy for selective maintenance requires a fair distribution of these resources, which can be achieved by incorporating balancing co...

Drones or Unmanned Aerial Vehicles (UAVs) have the potential to modernize and transform the logistics industry. They are compact, highly mobile, economical to operate, and most importantly, have a significantly smaller carbon footprint than traditional means of transportation. As a result, they have the capability to navigate our increasingly conge...

The joint selective maintenance and repairperson assignment problem with uncertain duration of maintenance actions is studied in this paper. This problem arises in mission-oriented assets that perform sequences of missions interspersed with scheduled pauses to allow maintenance activities. The goal is to find the optimal subset of components to mai...

In the majority of industrial sectors, manufacturing systems represent a significant portion of the capital. For the design, operation and management of these systems, integrated approaches have been well recognized to be effective and have hence attracted researchers from reliability, availability, and maintainability (RAMS), and operational resea...

The selective maintenance problem (SMP) arises in many mission-oriented multi-component systems that are operated for consecutive missions interspersed with finite breaks, during which only limited component repairs can be performed due to constrained resources. This NP-hard problem decides which components to maintain and to what levels of repair...

This paper studies the optimization of the joint selective maintenance and repairperson assignment problem when the quality of maintenance actions is uncertain, thus leading to uncertain post-maintenance reliability of system components. This situation is common in practice since maintenance actions are never perfect and are affected by several fac...

La prise de conscience grandissante de la nécessité de protéger les ressources de la planète et les objectifs de développement durable obligent les fabricants à récupérer et à remettre à neuf leurs produits usagés dans le cadre de programmes de responsabilité élargie des producteurs (REP). Afin de prolonger leur cycle de vie, les produits remanufac...

The COVID-19 pandemic has struck health service providers around the world with dire shortages, inflated prices, and volatile demand of personal protective equipment (PPE). This paper discusses supply chain resilience in the context of a Canadian provincial healthcare provider during the COVID-19 pandemic. A multi-period multi-objective mixed-integ...

This paper presents a novel column-generation-based approach for solving large-scale instances of the joint selective maintenance and repairperson assignment problem (JSM-RAP) for mission-oriented systems in industrial settings. Such systems perform consecutive missions separated by scheduled finite-duration breaks during which some of their compon...

Global supply chains have been undergoing profound changes, driven by economic, political, social, and technological factors. On the one hand, the growing concerns about environmental and social issues, e.g., climate change and environmental justice, have intensified consumers’ calls for action by governments and corporations toward more environmen...

This paper introduces and solves the joint maintenance and orienteering problem with an application to offshore wind farms. The quest for sustainable energy production is fueling the growth of offshore wind electricity generation. Energy producing offshore wind turbines are typically dispersed across several remote wind farms and must be maintained...

Many systems are required to perform a series of missions with finite breaks between successive missions. For such systems, one of the most widely used maintenance strategies is selective maintenance (SM). Under certain maintenance constraints, the SM problem (SMP) consist in selecting an optimal subset of feasible maintenance actions to maximize t...

The selective maintenance problem (SMP) arises in many multi-component systems that are operated for consecutive missions interspersed with finite breaks during which only a selected set of component repairs or replacements can be carried out due to limited time, budget, or resources. This NP-hard problem decides which components to select and whic...

Some agricultural industries such as livestock and poultry farming produce “growing items” whose weight and value constantly increase over time. Growing items and their related industries are vital in supplying the needed food and fiber for the world population. More importantly, concerns for the preservation of natural resources have led to sustai...

Extended warranties are widely adopted and accepted in the marketplace by manufacturers and retailers as it helps to enhance the customers' post-sale satisfaction. In closed-loop supply chains, the extended warranty not only generates profit for the manufacturer, but also provides warranty returns of the new products for remanufacturing. In this pa...

This paper introduces a solution method for the multimission selective maintenance problem (SMP) that combines column generation and genetic algorithms. The multimission SMP is an optimisation problem that arises when a system performs a sequence of missions separated by breaks of finite duration. During these finite breaks only a subset of possibl...

Mission-oriented industrial systems are designed to operate a sequence of alternate missions and scheduled breaks. During breaks, maintenance tasks are usually carried out to improve the system's performance for the next missions. Given the limited length of breaks as well as other maintenance resources, only a subset of components set can be maint...

Industrial environments such as manufacturing and transportation industries usually involve fleets of identical systems that must carry out several missions interspersed with scheduled finite breaks. Given the limited amount of maintenance resources and time available, only a restricted number of maintenance actions can be performed on selected com...

The fresh fruit agricultural and distribution sector is faced with risks and uncertainties from climate change, water scarcity, land-use increase for industrial and urban development, consumer behavior, and price volatility. The planning framework for production and distribution is highly complex as a result. Mathematical models have been developed...

Effective management of cotton production logistics (CPL) against volatile environmental conditions while maintaining product quality and yield at acceptable costs has become challenging due to increasing global population and consumption and climate change. In CPL, the harvesting, processing, and storage of cotton are all linked, prone to various...

With the growing awareness for sustainability, organizations have engaged in multiple initiatives to recover, remanufacture and extend the lifecycle of their products. The resulting closed-loop supply chains (CLSC) have been considerably studied under various conditions. This paper proposes an integrated model for the design of a multi-component mu...

In response to heightened pressure from customers who embrace sustainability, and in compliance with the Sustainable Development Goals set by the United Nations, an increasing number of organizations have implemented, mostly within their supply chains, initiatives to reduce their environmental impacts while enhancing their social responsibilities a...

In many industrial settings, there are systems designed to perform consecutive missions interspersed with finite breaks during which only a set of component repairs can be carried out due to limited time, budget, or resources. The decision maker then has to decide which components to repair in order to ensure a given performance level of the system...

This paper addresses the joint selective maintenance and repairperson assignment problem in multicomponent systems operating under random operating environments (OE). The systems carry out consecutive missions separated by scheduled breaks of finite length within which maintenance actions are performed. Current selective maintenance (SM) models ass...

The development of information technologies and e-commerce has allowed many companies to set up online platforms to sell their products in dual-channel supply chain (SC) networks. The double competition between new and remanufactured products within channels and across competing channels affects manufacturer and retailer pricing decisions. However,...

This paper presents a new variant of the selective maintenance problem (SMP) to jointly optimize the maintenance planning and resource allocation problems for multiple missions. The classical SMP deals with components and maintenance level selection with the aim of maximizing the system reliability given limited budget and break duration. Of the fe...

We present an optimization model for dragon fruit plantations in Vietnam. The timing of cultivating and harvesting decisions are taken into account as the dragon fruit plant has an approximately ten-year life cycle with maximum average yield in the fourth year. Another consideration also included is the prevalence of forward-buying contracts with l...

Due to its economic and environmental benefits, the remanufacturing industry has become vital and popular worldwide. The demand for remanufactured products highly depends on their price and warranty coverage offered, as these two features are the two most important to customers for signaling value and quality of the remanufactured products. This pa...

In closed-loop supply chain (CSLC) networks, low return quality reduces the number of usable cores and hence affects the strategic decision of facility location and sizing. This problem can be overcome by adding presorting centers in the CLSC network since presorting costs are typically lower than the costs incurred at subsequent processing stages....

The global agriculture sector faces many challenges in its mission to meet the increasing demand for food and fiber. Climate change, increasing population growth, emergence of crop diseases, damage to crops from rodents and critters, and shrinking farming land in some regions are among these challenges. Application of agrochemicals has proven to be...

This paper deals with the problem of the selective maintenance (SM) optimization for a series-parallel system. The system performs several missions with breaks between consecutive missions. To improve the system reliability during the next mission, its components are maintained during the breaks. Current models in the SM literature usually assume t...

This paper develops a bi-objective imperfect selective maintenance optimization model for a multicomponent system, which carries out missions interspersed with scheduled breaks. Imperfect maintenance (IM) actions are performed on the components during the break to increase the system reliability during the following mission. The level of maintenanc...

This paper addresses the joint selective maintenance and repairperson assignment problem (JSM--RAP) for complex multicomponent systems. The systems perform consecutive missions separated by scheduled finite duration breaks and are imperfectly maintained during the breaks. Current selective maintenance (SM) models usually assume that only one repair...

Remanufacturing is a sustainable development strategy for recovering product value and extending original item lifetimes through collection, inspection, testing, and restoration activities. Remanufacturing activities are typically carried out on products that have been returned by consumers, and the increasingly high flow of products spontaneously...

Application of agrochemicals on crops is important for plants protection. Multiple factors influence the application of agrochemicals on plants such as climatic conditions, crop characteristics and spraying system design. There is a need for reliable methods to investigate these properties more precisely with low cost and in reasonable time. In the...

Purpose Condition-based maintenance (CBM) has become a central maintenance approach because it performs more efficient diagnoses and prognoses based on equipment health condition compared to time-based methods. CBM models greatly inform maintenance decisions. This research examines three CBM fault prognostics models: logical analysis of data (LAD),...

This paper deals with the problem of the selective maintenance (SM) optimization for a series-parallel system. The system performs several missions with breaks between consecutive missions. To improve the system reliability during the next mission, its components are maintained during the breaks. Current models in the SM literature usually assume t...

This paper develops a bi-objective imperfect selective maintenance optimization model for a multicomponent system, which carries out missions interspersed with scheduled breaks. Imperfect maintenance (IM) actions are performed on the components during the break to increase the system reliability during the following mission. The level of maintenanc...

This paper addresses the maintenance optimization problem in a multicomponent system, carrying out several missions interspersed with scheduled finite breaks. Due to limited time, budget, or resources, maintenance actions can be only carried out on a limited set of components. The decision maker then has to decide which components to maintain to en...

The management of remanufactured products has become an important issue for manufacturers due to the associated economic benefits and the increase of sustainability awareness worldwide. Pricing is used as a control mechanism in remanufacturing management to adjust demand for new and remanufactured products and the potential market share cannibaliza...

This paper investigates the problem of optimally integrating production quality and condition-based maintenance in a stochastically deteriorating single- product, single-machine production system. Inspections are periodically performed on the system to assess its actual degradation status. The system is considered to be in ‘fail mode’ whenever its...

This paper addresses the joint selective maintenance and repairperson assignment problem (JSM–RAP) for complex multicomponent systems. The systems perform consecutive missions separated by scheduled finite duration breaks and are imperfectly maintained during the breaks. Current selective maintenance (SM) models usually assume that only one repair...

Growing awareness for sustainability and green legislation being implemented worldwide are forcing manufacturers and other organizations to recover and remanufacture used products to extend their lifecycles. These remanufactured products are send back to the marketplace or used in maintenance or used as replacement products to honour warranty offer...

This paper proposes a novel condition-based selective maintenance model for a multi-component system running multiple missions interspersed with scheduled intermission breaks. Each component in the system degrades according to a time-dependent stochastic process and fails whenever its degradation level reaches a pre-specified threshold. Failures of...

The selective maintenance problem (SMP) arises in many large multicomponent systems which are operated for consecutive missions interspersed with finite breaks during which only a selected set of component repairs or replacements can be carried out due to limited time, budget, or resources. The problem is to decide which components and degree of re...

Distribution of agro-chemicals through sprayer nozzles is very important because there is a significant loss of agro-chemicals such as pesticides during spraying due to non-uniformity of droplet and off-target drift. Improving the efficiency of spray pattern would reduce energy, costs and also minimize environmental pollution. In this paper, we exa...

Condition-based maintenance (CBM) has become a central maintenance approach because it performs more efficient diagnoses and prognoses based on equipment health condition compared to time-based methods. CBM models greatly inform maintenance decisions. This research examines three CBM fault prognostics models: Logical Analysis of Data (LAD), Artific...

In many industrial settings, there are systems designed to perform consecutive missions interspersed with finite breaks during which only a set of component repairs can be carried out due to limited time, budget, or resources. The decision maker then has to decide which components to repair in order to guarantee a given performance level. This is k...

This paper proposes a new integrated economic production quantity (EPQ) and condition-based maintenance (CBM) model for a stochastically deteriorating production system. Inspections are performed periodically to measure the real time degradation. The system fails (out-of-control) whenever its degradation is beyond a critical threshold level. In the...

It is common in many industrial settings to have large multicomponent systems perform consecutive missions interspersed with finite breaks during which a limited set of component repairs or replacements can be carried out due to limited time, budget, or resources. The decision maker then has to decide which components to repair in order to guarante...

The clearing function models the non-linear relationship between work-in-process and throughput and has been proposed for production planning in environments with queuing (congestion) effects. One approach in multi-product, multi-stage environments has been to model the clearing function at the bottleneck machine only. However, since the bottleneck...

Abstract

The design of reverse logistics and remanufacturing processes and the recovery of end-of-life products have been well-studied in the literature. Quality, reliability, maintenance and warranty for recovered products and the remanufacturing activities that extend their life are integral issues in reverse logistics. This paper reviews recent and relev...

The aim of this paper is to present a new closed-loop supply chain (CLSC) network design model for multi-component and multi-product systems. This integrated model is more representative of industrial operations and takes into account the following important design factors: multi-component products, design for disassembly, existence of a secondary...

This paper investigates the optimal age replacement policy for second-hand systems or products which start they second life-cycle in a more severe environment with an initial age that is uncertain. This uncertain age is modeled as a random variable following continuous probability distributions. A mathematical model is developed to minimize the tot...

With the increased awareness for sustainability, many engineered products are being recovered and reconditioned for secondary useful lives. These second-hand products can serve as replacement products to honour warranty pledges. This paper presents two mathematical models to determine the optimal combination rebate warranty policy when refurbished...

This paper deals with the selective maintenance problem for a multi-component system performing consecutive missions separated by scheduled breaks. To increase the probability of successfully completing its next mission, the system components are maintained during the break. A list of potential imperfect maintenance actions on each component, rangi...

Upgrade operations are improvement actions that can be carried out on recovered end-of-life systems to rejuvenate them and make them fit for subsequent lifecycles. These operations are costly but improve the reliability of these second-hand systems and consequently can reduce their maintenance costs. In this paper, a mathematical model for the join...

This paper deals with the selective maintenance problem for a multi-component system performing consecutive missions separated by scheduled breaks. To increase the probability of successfully completing its next mission, the system components are maintained during the break. A list of potential imperfect maintenance actions on each component, rangi...

The aim of this paper is to present a new closed-loop supply chain (CLSC) network design model for multi-component and multi-product systems. This integrated model is more representative of industrial operations and takes into account the following important design factors: multi-component products, design for disassembly, existence of a secondary...

The process of remanufacturing is attractive economically and environmentally for both manufacturers and customers. This paper addresses a problem in the repairable spare parts remanufacturing industry to find the cost-optimal production strategy incorporating reconditioned components. New and reconditioned components are used to carry out replacem...

The clearing function models the non-linear relationship between WIP and through-put and has been proposed for production planning in environments with queuing (congestion) effects. However, incorporating clearing function concept in multi-product manufacturing networks is challenging. The traditional approach has been to model the clearing functio...

Remanufacturing processes such as refurbishing and reconditioning can extend the life of a product returned from the field. This provides financial opportunities and allows manufacturers to engage in sustainable practices. However, the inability to access a sufficient quantity of reconditioned components from end-of-life products can force the conc...

The problem of makespan minimization for parallel machine scheduling with multiple non-availability periods for non-resumable, semi-resumable and resumable jobs is considered in this paper. The discussion of this problem is very limited in the current state of the literature, with most cases only considering a small subset of the problem such as a...

As municipal and regional initiatives for the collection of recyclable products, such as plastic, metal, glass, paper, etc., are increasing across the globe, designing collection networks to minimize collection costs and reduce associated greenhouse gas emissions are becoming important. In this study, a two-phase mathematical decomposition model fo...

The clearing function models the non-linear relationship between WIP and throughput and has been proposed for production planning in environments with queuing (congestion) effects. However, incorporating clearing function concept in multi-product manufacturing networks is challenging. The traditional approach has been to model the clearing function...

This paper addresses the selective maintenance optimization problem for a multi-mission series-parallel system. Such a system experiences several missions with breaks between successive missions. To improve the reliability of the system, preventive maintenance actions are performed during breaks. Each preventive maintenance action is characterized...

This paper addresses the selective maintenance optimization problem for a multi-mission series-parallel system. Such a system experiences several missions with breaks between successive missions. To improve the reliability of the system, preventive maintenance actions are performed during breaks. Each preventive maintenance action is characterized...

This paper investigates the preventive age replacement policy (ARP) for a system subject to random failures. Unlike most maintenance models in the literature, our model considers a system that is exploited under different operating environments each characterized by its own degree of severity. The system lifetimes follow a different distribution de...

For complex systems operating in critical environments, original equipment manufacturers, operators and/or regulators often specify replacement intervals for major components before failure can occur. The fixed costs to teardown the overall system can be an important constituent of the total costs. Thus, when a preventive maintenance is scheduled t...

Closed-loop supply chain network (CLSCN) design aims to incorporate environmental considerations into the traditional supply chain design by including recycling, disassembly and reuse activities. A CLSCN incorporates the use and reuse of environmentally friendly products and materials supported by the design of an appropriate recovery, disassembly,...

The collection and recovery of end-of-life products has been a very successful research area especially around the design of reverse logistics and remanufacturing processes. Unfortunately, there is very little work on the issues of quality, reliability, maintenance & warranty for these recovered products and the remanufacturing activities that will...