A Lean transportation approach for improving emergency medical operations

Abstract

This paper extends the approach of Lean transportation to improve the performance of emergency medical processes (EMP) by adapting its main concepts into the main characteristics of the EMP environment. The paper is based on an inductive theory-building process initiated from a case study in the field of emergency medical services. The development of the suggested performance improvement approach triggered from an exhaustive analysis of a process involved and an exploratory review of the existing improvement approaches available. The process of concern can be described as a specialized transportation process, where human lives are at risk. Its characteristics led to a natural application of Lean transportation. The results include, a novel approach for improving the agility and efficient EMS processes. This is validated with an application for improving ambulance response times and turnaround times of the Red Cross operations located in Monterrey, Mexico. The approach proved to be an integrated scheme for identifying waste opportunities at a systems level. This characteristic is important to let operations management prioritize improvement efforts in a limited budget situation. This work suggests the application of the emerging Lean transportation approach for increasing the agility performance of EMS processes.     

Applying a longitudinal interpretive multi-case research method to study the employee impact of operations management systems in a micro firm setting

Abstract

While many operations management journals are now publishing interpretive studies, there is still a need for more material on how to carry out such work under the interpretive gestalt. By offering a research account of a longitudinal interpretive multi-case study, this paper seeks to contribute to the literary gap in ‘how to do it [interpretive research]’. The purpose of this paper is to document a longitudinal operations management study in three micro-firms, where the catalyst for this study is the implementation of an electronic operations management system in each case. The paper chronicles the authors’ experience in a four-year multi-case study, and as such provides insight into design, development and execution of longitudinal interpretive operations management research, and the building of a theoretical model. While blueprints are not the purpose of such reflections, they can provide insight and advice to researchers, which is the underlying goal of this paper.     

On step fixed-charge transportation problem

The fixed-charge problem is a nonlinear programming problem of practical interest in business and industry. One of its variations is the fixed-charge transportation problem (FCTP) where fixed cost is incurred for every route that is used in the solution, along with the variable cost that is proportional to the amount shipped. That cost structure causes the value of the objective function Z to also behave like a step function. Each time we open or close a route the objective function jumps a step. The step fixed-charge transportation problem (SFCTP) is a variation of the FCTP where the fixed cost is in the form of a step function dependent on the load in a given route. While the value of the objective function Z in the FCTP is a step function, the introduction of the step fixed cost in the SFCTP results in the objective function Z being itself a step function with many more steps. Fixed-charge problems are usually solved using sophisticated analytical or computer software. This paper discusses the theory of SFCTP and presents a computationally simple heuristic algorithm for solving small SFCTPs.     

Improving throughput for an electronic assembly line using a constraint analysis methodology

Electronic assembly operations are vital to industries such as telecommunications, computers and consumer electronics. This paper presents a constraint analysis methodology for planning and improving electronic assembly operations that draws on concepts from queueing theory, simulation and production planning. The proposed methodology identifies the operational bottleneck and predicts the utilization, throughput and lead time of the assembly line. It also quantifies the relationship between yields and utilization for the assembly operations. A case study is presented that applies the methodology at an Ericsson, Inc., telecommunications equipment assembly facility. The constraint analysis methodology provided valuable decision support as the managers of Ericsson evaluated the costs and benefits of additional production capacity. Although the focus of this paper is electronic assembly operations, the methodology can be applied to general flow line assembly systems with feedback loops for test and rework under dedicated high-volume production.     

Flow shop scheduling by transportation model

This paper describes the classical problem of scheduling n jobs on m machines in a flow shop. A schedule evaluation algorithm is presented, which for job-pairs, generates a schedule evaluation matrix. The matrix is the input data to a transportation problem, the solution of which gives near-optimal jobsequence and makespan. The performance of the algorithm is discussed.     

供需未匹配的多车场多车型多货品可拆分取送货车辆路径问题

取送货车辆路径问题在多点调拨系统普遍存在,属于NP-hard问题。该问题研究通常需考虑车场数、车型种类、货品种类、客户服务次数等诸多因素,已有文献多假设客户间供需已匹配、单车场、单车型、单货品和取送货需求一次性满足,优化目标多设置为总路径最短。而从企业运营实践来看,运输方案不仅要规划客户间访问路径,还需进行客户间供需匹配;运输成本不仅与运距有关,还涉及运输货品的重量和派车成本;运输网络中多车场、多车型和多货品更加常见,且客户需求量往往大于车辆装载能力。因此,本文首次尝试基于"运距×运量"的车辆路径成本和基于额定吨位的固定派车成本之和最小为优化目标,建立同时考虑多车场、多车型、多货品、客户间供需未匹配和需求可拆分的取送货车辆路径问题模型,并设计基于大规模邻域搜索的迭代局部搜索求解算法。该算法采用基于运输效率提升的贪婪思想来快速构建高质量初始可行解,并通过引入四种移除算子、两种修复算子和车场车型调整优化策略形成大规模可行搜索邻域以增强全局寻优能力。基于18个文献算例和6个企业实例的数值实验结果表明：1）本文提出的算法在求解质量和求解效率方面均优于相关文献中的算法;2）相对人工调拨方案,本文设计的方案能够帮助企业节约33%的运输成本和21%的车次。本研究不仅可拓展取送货车辆路径问题现有理论,而且可为企业实际运营提供决策支持。     

Best routes selection in multimodal networks using multi-objective genetic algorithm

In this study, we propose a bi-level multi-objective Taguchi genetic algorithm for a multimodal routing problem with time windows. The mathematic model is constructed, which is featured by two optimal objectives, multiple available transportation manners and different demanded delivery times. After thoroughly analyzing the characteristics of the formulated model, a corresponding bi-level multi-objective Taguchi genetic algorithm is designed to find the Pareto-optimal front. At the upper level, a genetic multi-objective algorithm simultaneously searches the Pareto-optimal front and provides the most feasible routing path choices for the lower level. After generalizing the matrices of costs and time in a multimodal transportation network, the \(k\) -shortest path algorithm is applied to providing some potential feasible paths. A multi-objective genetic algorithm is proposed at the lower level to determine the local optimal combination of transportation manners for these potential feasible paths. To make the genetic algorithm more robust, sounder and faster, the Taguchi (orthogonal) experimental design method is adopted in generating the initial population and the crossover operator. The case study shows that the proposed algorithm can effectively find the Pareto-optimal front solutions and offer series of transportation routes with best combinations of transportation manners. The shipper can easily select the required shipping schemes with specified demands.     

Contextualist-retroductive case study design for strategic asset management research

Abstract

This paper develops a tailored case study design for strategic asset management research. It draws on the notions of ‘contextualist approach’ and ‘retroductive strategy’ used in case study research, and follows the multiple embedded-case design advocated within qualitative research. Using a published asset management research study as a primer, it demonstrates the application of the proposed research design and its methodological rigour. This research design could serve as a reference framework, as well as a research instrument, for guiding asset management research. As such, it facilitates the development of theory that accounts for the multi-faceted nature and current priorities of asset management. Overall, this research design helps determine what activities to be incorporated into an asset management program to enhance an organization’s ability to capture value from its operations system. In so doing, it promotes a holistic perspective on asset management that is currently lacking in the literature.     

基于时间价值的交通出行方式选择行为研究

通勤出行是城市居民最基本和最重要的出行目的,通勤出行时间价值是评价通勤出行者对交通方式选择的重要参数之一,以累积前景理论为基础,将通勤出行时间价值引入广义出行成本函数中,以权重函数和改进的广义出行成本函数作为交通方式选择模型的依据,并在模型中自定义广义出行成本参考点,选择累积前景值最大的前景作为出行者最优决策。分别基于“期望效用最大化理论”和“累积前景理论”对通勤出行者在三种不同出行场景下进行仿真模拟,研究最优交通方式选择行为。研究结果表明:期望效用理论框架下,通勤出行者的交通方式选择行为不受出行场景的影响,累积前景理论更适用于出行方式选择行为的研究。构建以通勤出行时间价值为核心变量的交通方式选择模型,可帮助通勤出行者选择合理的交通方式,并为政府及相关部门制定交通管理规划和实施缓解交通拥堵政策提供依据。     

Coordinated Logistics: Joint Replenishment with Capacitated Transportation for a Supply Chain

In this study, we consider the integrated inventory replenishment and transportation operations in a supply chain where the orders placed by the downstream retailer are dispatched by the upstream warehouse via an in‐house fleet of limited size. We first consider the single‐item single‐echelon case where the retailer operates with a quantity based replenishment policy, (r,Q), and the warehouse is an ample supplier. We model the transportation operations as a queueing system and derive the operating characteristics of the system in exact terms. We extend this basic model to a two‐echelon supply chain where the warehouse employs a base‐stock policy. The departure process of the warehouse is characterized in distribution, which is then approximated by an Erlang arrival process by matching the first two moments for the analysis of the transportation queueing system. The operating characteristics and the expected cost rate are derived. An extension of this system to multiple retailers is also discussed. Numerical results are presented to illustrate the performance and the sensitivity of the models and the value of coordinating inventory and transportation operations.     

Vehicle Replacement in the International Committee of the Red Cross

This article studies 4 × 4 vehicle replacement within the International Committee of the Red Cross (ICRC), one of the largest humanitarian organizations. ICRC policy sets the replacement of vehicles at 5 years or 150,000 km, whichever comes first. Using field data collected at the ICRC headquarters and national level we study the ICRC policy. Our results suggest that the organization can make considerable savings by adjusting its replacement policy. This study contributes to the area of logistics and transportation research in humanitarian operations.     

Bi-objective multi-resource scheduling problem for emergency relief operations

Abstract

Resource scheduling for emergency relief operations is complex as it has many constraints. However, an effective allocation and sequencing of resources are crucial for the minimization of the completion times in emergency relief operations. Despite the importance of such decisions, only a few mathematical models of emergency relief operations have been studied. This article presents a bi-objective mixed integer programming (MIP) that helps to minimize both the total weighted time of completion of the demand points and the makespan of the total emergency relief operation. A two-phase method is developed to solve the bi-objective MIP problem. Additionally, a case study of hospital network in the Melbourne metropolitan area is used to evaluate the model. The results indicate that the model can successfully support the decisions required in the optimal resource scheduling of emergency relief operations.     

Supporting collaboration in humanitarian supply chains – insights from a design science project

Abstract

The growing number of large-scale relief operations and humanitarian aid initiatives is stretching the resources – financial, material and human – of humanitarian actors to their limits. Challenges to collaborate both within international humanitarian organizations, and among their direct and indirect supply chain partners often contribute to the inefficient use of resources, or ineffective operations. In this research, we discuss collaboration in humanitarian supply chains, and analyze causes of their dysfunctional operations. Furthermore, we develop an experiential learning approach that can sensitize humanitarian supply chain actors to causes of information distortion. The simulation approach was implemented in the field and instructional design cycles yielded insights into how staff apply their learnings under the specific conditions of humanitarian relief work.     

Manufacturing cycle time reduction using balance control in the semiconductor fabrication line

In semiconductor manufacturing, wafer fabrication is the most complicated and important process, and is composed of several hundred process steps and involves several hundred machines. The productivity of the manufacturing process depends mainly on controlling the balance of WIP (work-inprogress) flow to achieve maximum throughput under short manufacturing cycle times. This paper discusses how to determine the proper WIP level for operations, against which balance status can be measured. Balance measurement can be applied in mathematical modelling for bottleneck scheduling and operations management of the fabrication line. Performances are evaluated through computational experiments to show that balance driven management leads to 15-33% more production in 21% shorter manufacturing cycle time than production driven management.     

Kanban optimization by simulation and evolution

The problem of the optimal design of multistage systems with Kanban control mechanism is investigated. The optimization problem generalizes those from literature by considering a general criterion function and including the lot sizes as decision variables. Since no analytical solutions can be expected simulation combined with a genetic algorithm is used. The simulator KaSimIR as well as the optimization tool LEO are briefly described. Some examples demonstrate the usability of the approach.     

A Preliminary Laboratory Evaluation: Effects of Consequence Quality and Ratio-Schedule Arrangements on Staff Performance

ABSTRACT

Supplementary, contingent pay arrangements can result in improved employee productivity and increased job satisfaction. We examined the effects of four stimulus delivery arrangements on performance in a computer-based task in a simulated work context. Three participants entered hypothetical client data onto a Microsoft Excel® invoice and earned gift-cards for task completion according to the following conditions: (a) fixed-ratio/high-preference stimuli (FR/HiP), (b) variable-ratio/high-preference stimuli (VR/HiP), (c) fixed-ratio/varied stimuli (FR/Var), and (d) variable-ratio/varied stimuli (VR/Var). For two of three participants varied reinforcers produced similar levels of responding to high-preference stimuli regardless of schedule type, whereas varied reinforcers did not support responding for the third participant. All participants preferred working under conditions of access to high-preference reinforcers. Results are discussed in light of creating efficient performance improvement plans in organizational settings.     

Evaluation of safety stock methods in multilevel material requirements planning (MRP) systems

This paper evaluates alternative methods of establishing the safety stock level taking into consideration of historical measures of forecasting accuracy and the needs for master production scheduling and material requirement planning under a rolling time horizon. A computer model is used to simulate the forecasting, master production scheduling and material planning activities in a company that produces to stock and the production activities are managed by multilevel MRP systems. The simulation output is analysed to evaluate the impact of safety stock methods on MRP system performance. The result of the study shows that using safety stock can help to reduce total cost, schedule instability and improve service level in the MRP systems. Guidelines are developed to help managers select methods to determine safety stock in MRP system operations.     

Product architecture,global operations networks,and operational performance: an exploratory study

Abstract

This paper investigates the relationships between product architectures and global operations networks and their impact on operational performance, based on survey data from 82 Swedish manufacturers. We find that modular and integral product architectures are associated with different characteristics of the global operations network, and that global operations network designs are characterised by three dimensions: network, plant and supply chain. The key aspects are network structure (configuration as well as coordination), plant focus (scale or scope) and the locus of supply chain capabilities (internal or external).     

Cardiac measures of stress in British prison officers

Abstract

Previous research has found that alternative employment arrangements are associated with both impaired and improved well-being. Since such inconsistencies are likely to derive from the type of employment contract as well as the characteristics of the job, this paper compares permanent full-time work with forms of alternative employment (permanent part-time, fixed-term and on-call work) in order to investigate how different employment contracts and perceptions of job conditions relate to individual well-being. This study contributes to the literature by addressing several questions. Different forms of alternative employment are distinguished and individual background characteristics that might be intertwined with the employment contract are controlled for. Moreover, the scope of this study extends to the effects of perceived job conditions, and possible interactive effects with type of employment are tested. Analyses of questionnaire data from 954 Swedish healthcare workers show that perceptions of the job (job insecurity, job control and demands), but not the type of employment contract, predicted health complaints. However, type of employment interacted with perceptions of job insecurity, in that insecurity was associated with impaired well-being among permanent full-time workers, while no relationship was found for on-call or core part-time employees. Despite the absence of interactions between employment contract and job demands or job control, it can be concluded that knowledge about the relationship between alternative employment arrangements and the well-being of workers can be enhanced when the combined effects of employment contract and job conditions are studied.