We study supplier–buyer relationships in smallholder agri-food supply chains with equity concerns and under stakeholder engagement. We develop a game theoretic model to study the impact of these socially responsible practices in investment and pricing decisions. We model this as a Stackelberg game and study the impacts of the power structure in the outcomes. Our work was motivated by the business model

Workload control (WLC) is a lean oriented system that reduces queues and waiting times, by imposing a cap to the workload released to the shop floor. Unfortunately, WLC performance does not systematically outperform that of push operating systems, with undersaturated utilizations levels and optimized dispatching rules. To address this issue, many scientific works made use of complex job-release mechanisms

Overcrowding at emergency departments in Hong Kong has been a critical issue for hospital managers recently. In this study, we focus on optimizing the medical staff configuration to alleviate overcrowding. According to the service requirements proposed by the Hong Kong government, 90% of urgent patients should receive treatment within 30 min. However, this condition is rarely satisfied in the practical

The cargo fare class mix (CFCM) problem aims to find the optimal fare class mix for a given intermodal transportation network based on known client demands. It is based on a revenue management problem for aviation passengers, the fare class mix problem, but considering intermodal cargo transportation, two major differences apply. Firstly, the CFCM’s premise is that long-term commitments to customers

To improve the efficiency of the container terminals, we propose a simulation optimization iteration approach to integrate the yard allocation problem (YAP) with the vehicle congestion problem. YAP is formulated as a mixed integer programming model to reduce the total job travel time. A discrete event simulation model is developed to simulate the terminal operation and traffic movement within the terminal

Increased customization has strengthened the importance of make-to-order companies. The advent of lean management and the introduction of smart and flexible technologies has enabled many of these companies to create flow shop routings. Order review and release (ORR) research, which originally focused on job shops, has started paying attention to flow shops. However, the results have not provided clarity

We consider the problem of designing a logistics system to assure efficient urban construction processes for an innovative urban building area in the city of Vienna. We address the challenges of coordinating workers and the timely delivery and storage of material with the objective of optimizing resource-efficiency as well as reducing traffic related to construction tasks. The problem is formulated

Emergency departments (EDs) are continuously exploring opportunities to improve their efficiency. A new opportunity lies in revising the patient–physician assignment process by limiting the number of patients simultaneously assigned to a single physician, which is defined as the application of a case manager approach with limited caseloads. The potential of introducing a case manager approach with

The manufacturing industry has evolved in the past few years due to the competitive global economy where the performance of its assembly line operations is primarily dependent upon optimum resource utilization. The assembly line operations are balanced among the available resources to obtain an equal amount of workload to achieve optimum resource utilization, called the assembly line balancing (ALB)

Conventional approaches to layout design of block stacked warehouses assume perfect staggering of product inflow leading to perfect sharing of space among products. Since such an assumption is seldom true, we argue that warehouses designed using the conventional approach may result in choking situations with large quantities of inventory waiting outside the storage areas. On the other hand, liberal

The size of container ships and the number of containers being transshipped at container terminals have steadily increased over the years. Consequently, it is important to make efficient use of the hinterland capacity. A concept that is used to do this is synchromodal transportation, in which at the very last moment the mode of transportation for a container is decided. Unfortunately, some deep-sea

The drying of sawn lumber is one of the major processing steps in sawmills with high production volumes. Existing publications on kiln drying analyse and improve technological conditions, while this paper focuses on the scheduling and loading planning with time availability of the individual dried packages. To improve dry kiln scheduling for multiple and identical kilns in large softwood processing

Over the past decades, container transportation has achieved considerable growth, and maritime trade now constitutes 80% of the global trade. The vessel sizes increased in parallel, up to 21,400 TEU (Twenty-foot-equivalent unit container). Accordingly, global containerized trade reached up to 150 million TEU in 2017 (UNCTAD 2018). This growth brings the need to use scientific methods to manage and

Supply chain system experiences variance amplification in order replenishment and inventory level, leading to severe inefficiencies of the system. Information distortion is universally known as a fundamental reason for the variance amplification phenomenon. The purpose of this paper is to study the effect of demand information sharing in reducing bullwhip effect and improving the robustness of supply

In this paper, we analyze the impact of indirect network effects and competition on two firms each offering two complementary products. We first formulate the pricing game with general network effects and show that it is neither a supermodular nor a submodular game. We then derive the closed-form Nash equilibrium with linear demand functions. Furthermore, we examine a model with two symmetric firms

Building robust logistics networks against facility disruptions has been gaining more attention from both researchers and practitioners. However, in pursuit of high built-in network robustness, one usually has to increase the network redundancy and complexity, which adds to the difficulty of management and induces additional operating costs. In this paper, we aim to balance the trade-off between robustness

Shift design is an essential step in workforce planning in which staffing requirements must be obtained for a set of shifts which best cover forecasted demand given as a demand pattern. Existing models for this challenging optimization problem perform well when these demand patterns fluctuate around an average without any strong variability in demand. However, when demand is irregular, these models

In this paper, we study a service parts inventory management system for a single product at a parts distribution center serving two priority-demand classes: critical and non-critical. Distribution center keeps a common inventory pool to serve the two demand classes, and provides differentiated levels of service by means of inventory rationing. We assume a continuous review one-for-one ordering policy

Remanufacturing capacities are constrained by the collected amount of end-of-life (EOL) products resulting in the make-from-stock model for remanufacturing industries. Remanufacturers may select quality choices in a strategic manner to improve their remanufacturing capacities. Thus, we examine a Cournot duopoly in which an original equipment manufacturer (OEM) sells new products and an independent

This paper develops an integrated imperfect production-inventory system consisting of a retailer and a manufacturer who produces breakable items. As breakable items are very sensitive to transport, in this paper, to stimulate the retailer, the manufacturer offers (1) free transportation subject to the condition that the retailer must have to order a minimum replenishment quantity specified by the manufacturer

The purpose of this paper is to explore the cooperation issues in a consignment supply chain with complementary products under Online to Offline Business Mode (O2O mode). The centralized, decentralized and cooperative game-theoretic decision models are developed, analyzed and compared for a generic consignment supply chain with complementary products under O2O mode. Similar models are also developed

In this study, we address safety stock positioning when demand per period is a known constant but supply is uncertain. The supply is either available or not available, while the setting is that of a periodically reviewed, serial system following a base stock policy. Each stage is allowed to operate according to the guaranteed or stochastic service model. We use a Discrete Time Markov Chain model for

In radiotherapy, treatment needs to be delivered in time. Long waiting times can result in patient anxiety and growth of tumors. They are often caused by inefficient use of radiotherapy equipment, the linear accelerators (LINACs). However, making an efficient schedule is very challenging, especially when we have multiple types of patients, having different service requirements and waiting time constraints

Maintenance and production are frequently managed as separate activities although they do interact. Disruptive events such as machine failures may find the company unready to repair the machine immediately leading to time waste. Preventive Maintenance may be carried out and maintenance time reduced to the effective task duration, in order to prevent time waste. Companies and researchers have been focusing

Cost-effectiveness analysis is an important topic in public health, which can provide valuable information for medical decisions. Several modeling methods are available for conducting cost-effectiveness analysis. However, it is difficult when the data is incomplete. To solve this problem, a Markov model is proposed to model patients’ health states transition, and two hybrid metaheuristics are proposed

This article presents a new model for constructing annual schedules for medical residents based on the regulations of a German teaching hospital as well as the program restrictions of the German Medical Association. Since resident programs of physicians do not only vary between disciplines but also between countries, it is essential to evaluate the main characteristics of the program. The main difference

This paper addresses a permutation flowshop scheduling problem, with the objective of minimizing total weighted squared tardiness. The focus is on providing efficient procedures that can quickly solve medium or even large instances. Within this context, we first present multiple dispatching heuristics. These include general rules suited to various due date-related environments, heuristics developed

Reacting quickly to changing market demands and new variants by improving and adapting industrial systems is an important business advantage. Changes to systems are costly; especially when those systems are already in place. Resources invested should be targeted so that the results of the improvements are maximized. One method allowing this is the combination of discrete event simulation, aggregated

This paper is concerned with stochastic scheduling of production and maintenance activities in a permutation flow shop setting. We present a two-stage stochastic mixed-integer program (SMIP) that adapts the conventional permutation flow shop scheduling problem for incorporating multiple preventive maintenance activities with various meter-based intervals. The model handles uncertainties in both processing

This paper proposes a new ant colony optimization (ACO) algorithm suitable for integrated process planning and scheduling (IPPS) that optimizes both process planning and scheduling simultaneously. The IPPS covered in this study, when compared to the conventional IPPS, is more flexible and complicated because sequence-dependent setups and tool-related capacity constraints are additionally considered

Nowadays the successful operation of a company is unimaginable without fast and reliable communication. As a result, so-called Communication Service Providers play an important role in today’s business life. Their orders have to be carried out promptly and dependably, let them be requests for new installations, modifications, or maintenance tasks. These orders have to be performed at different locations

This paper deals with the evaluation of the expected shortfall or the conditional value-at-risk for the makespan in scheduling problems represented as temporal networks under incomplete and uncertain information. We consider temporal activity network representations of scheduling problems affected by uncertainties related to the activity durations and we assume that for these uncertainties only incomplete

In this paper, we present a simulation-based headway optimization for urban mass rapid transit networks. The underlying discrete event simulation model contains several stochastic elements, including time-dependent demand and turning maneuver times as well as direction-dependent vehicle travel and passenger transfer times. Passenger creation is a Poisson process that uses hourly origin–destination-matrices

Appointment scheduling systems represent a method to manage patient waiting lists effectively. This work advances an innovative quantitative approach for the outpatient appointment scheduling problems, based on an optimization model, to manage outpatient Day Service operations. It focuses on outpatient appointment scheduling. We start from earlier works in the literature to design models with the objective

This article considers a closed-loop green supply chain with both forward and reverse dual-channels, where a manufacturer produces and sells a single green product to the potential customers through both the direct online channel (e-tail/internet) and the traditional retail channel in the forward dual-channel, and collects the used products for remanufacturing from the customers through both the retail

This study investigates the operations of a healthcare alliance, where two types of independent hospitals [general hospitals (GHs) and community healthcare centers (CHCs)] collaborate in capacity allocation and revenue management to improve efficiency and revenue. Specifically, the GH allocates part of its capacity to establish a dedicated green channel for referral patients from the CHC based on a

Two-echelon vehicle routing problems which contain synchronization between vehicles can be deeply impacted by time uncertainty, because one vehicle’s delay can propagate to other vehicles. In this paper, we evaluate the deterministic solution of such a problem based on simulated travel time scenarios. The information obtained by simulation is incorporated in the optimization procedure iteratively.

In acute care, a patient’s clinical deterioration is often a precursor to serious and often fatal outcomes. To reduce the severity and frequency of negative outcomes, care providers need to response rapidly by providing quick evaluation, triage, and treatment to patients with declining conditions. However, a provider’s availability to respond can be constrained when multiple patients are deteriorating

Supply chain networks in the photovoltaic sector were faced with a rapid decline in prices during the past few years, which is predicted to go on in the following years. These circumstances force related companies to coordinate production, distribution and transportation planning of all their network sites thoroughly. Moreover, continuous-time scheduling of processes is required to determine times

In this article an improved multi-commodity network flow (MCNF) model is introduced to holistically assess a multi modal transportation system and to identify the optimal flows achievable. The principal innovation of this model, that distinguishes it from recent approaches, is the inclusion of flow reduction functions (FRF) to automatically scale the flows on specific parts of the network. Reduced

Public-interest goods benefit consumers and also generate external benefits boosting societal welfare. Despite this characteristic of these goods, their level of consumption or production are generally well below the socially desirable levels without intervention. Motivated by influenza vaccine market, this paper examines the intervention design problem for a public-interest good facing yield uncertainty

This paper investigates the problem of inter-terminal movements of containers and vehicles within a port area in order to achieve an integrated and effective transport within the port and towards the hinterland. Containers from different port terminals are first moved to a rail yard and then delivered to the hinterland by rail. To provide insights for stakeholders such as port authority and terminal

This paper examines the berth allocation problem under uncertainty. We use uncertainty sets to describe the possible scenarios without depending on probabilistic information. Then we adopt a two-stage robust optimization approach where baseline schedule is made before and the recovery operation is made after the disruptions are known. Three two-stage robust models are constructed to generate less conservative

Motivated by challenges faced by a biopharmaceutical firm, we extend the traditional process flexibility modeling literature by integrating inventory storage capabilities into these models, and develop general guidelines on how to design an effective supply chain network in this setting. Given the expense of inventory storage in the biopharmaceutical industry, the firm is considering incorporating

To ensure that patients are appropriately prepared for surgical procedures in a welcoming environment, the Sir Mortimer B. Davis Jewish General Hospital, a McGill University affiliated teaching hospital located in Montreal, is redesigning and relocating its existing presurgical screening clinic so that it provides additional services and is more patient friendly. Given the services being added, limited

We compare the optimal buffer allocation of a manufacturing flow line operating under three different production control policies: installation buffer (IB), echelon buffer (EB), and CONWIP (CW). IB is the conventional policy where each machine may store the parts that it produces only in its immediate downstream buffer if the next machine is occupied. EB is a more flexible policy where each machine

Home health care (HHC) consists of care services provided to patients at their domicile rather than in hospitals or other health facilities. HHC human resources are largely studied in the optimization literature, to improve service quality and efficiency. However, the growth of complex HHC services that include the delivery of devices and disposable materials makes it necessary to include them in the

Appointment overbooking has been commonly adopted for the mitigation of the adverse consequences of patient no-shows, such as reduced resource utilization and revenue. However, if there are more patients showing up than expected, the resource overtime and patient waiting time can increase. Due to the theoretical interest and the practical importance of the problem, there has been much research on the

We study the problem of the integrated scheduling of drayage operations and long-haul transport in synchromodality. Although different in time span and characteristics of execution, these two processes have an impact on each other and their interaction has a direct influence on the overall performance of the transport network over time. We propose a simulation based integration of a Mixed-Integer Linear

A methodology is proposed to provide a guided process for modularization of manufacturing system components within the broader design process. The application focus is on manufacturing systems, including flow processes. Component clusters are formed by simultaneously considering physical-functional and strategic drivers that are fundamental to a more holistic partitioning of the system. The clustering

Trucking companies deliver a large number of containers every day to container terminals at hub ports. Truck drivers for the delivery operation can experience long waiting times when they arrive at peak hours. This study proposes a scheduling method for appointments that considers the cost of trucks staying in the terminal, demurrage cost, container delivery cost, number of appointments allowed at

High-tech industries are experiencing accelerated technological change, which causes rapid obsolescence of invested manufacturing equipment. In such environment, the impact of the new technologies must be carefully considered while making decisions involved in resource acquisition or replacement. In this study, we consider a capacity planning problem with the presence of uncertain magnitude and timing

Failure-prone manufacturing systems facing dynamical market conditions that result in demand variations are considered. The combined production and corrective maintenance optimization problem for a one-machine-one-product system is addressed. Repairing the machine after the failure, the manager has to solve the dilemma: to choose an inexpensive (but lower) repair rate, or to use the higher, (but more

We consider the question whether or not high volume automotive production sites can be transformed to the basic concept of stabilized production. The problem is motivated by the necessity of car producers to transform their existing plants to this production system in order to deal with the increasing complexity of the manufacturing process. To successfully answer this question the long term stability

A modelling methodology is presented for assembly/disassembly systems with general processing time distributions and finite buffers. The approach combines the distributions discretization and a decomposition technique to analyze large manufacturing systems in a reasonable computational time and with good accuracy. In the decomposition technique, the system is decomposed into two station subsystems

Managing patient to bed allocations is an everyday task in hospitals which in recent years has moved into focus due to a general rise in occupancy levels and the resulting need to efficiently manage tight hospital bed-capacities. This holds true especially when being faced with high volatility and uncertainty regarding patient arrivals and lengths of stay. In our work with a large German hospital we

The Emergency Department (ED) management presents a really high complexity due to the admissions of patients with a wide variety of diseases and different urgency, which require the execution of different activities involving human and medical resources. This can have an impact on ED overcrowding that may affect the quality and access of health care. In this paper we propose an ad hoc process mining

Empirical studies show that the inter-event times of a production system are correlated. However, most of the analytical studies for the analysis and control of production systems ignore correlation. In this study, we show that real-time data collected from a manufacturing system can be used to build a Markovian arrival processes (MAP) model that captures correlation in inter-event times. The obtained

This paper addresses the solution methods for the stochastic home-caregiver scheduling and routing problem which arises in many service industries such as home care and home health care. In the problem, the caregiver’s travel times and service times for customers are stochastic. A chance constraint is introduced to ensure the on-time service probability for the customers. Such stochastic travelling

In this paper we propose a heuristic approach that computes the order in which patients will be treated in an ambulatory chemotherapy center. Each patient follows an individual treatment plan that fixes dates for series of drug injections separated by recovery periods. The daily care process has three steps: consultation with the oncologist, drug preparation in the pharmacy and drug injection in medical