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Articles 151 - 180 of 289

Full-Text Articles in Operations and Supply Chain Management

A Lagrangian Relaxation For Capacitated Single Allocation P-Hub Median Problem With Multiple Capacity Levels, Ching-Jung Ting, Kuo-Rui Lu Jan 2016

A Lagrangian Relaxation For Capacitated Single Allocation P-Hub Median Problem With Multiple Capacity Levels, Ching-Jung Ting, Kuo-Rui Lu

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

In this paper we consider a capacitated single allocation p-hub median problem with multiple capacity levels (CSApHMPMC) in which the decisions are to determine the location of p hubs and their capacity levels, the single allocation of non-hub nodes to hubs in the logistics network. This problem is formulated as an integer programming model with the objective of minimizing the sum of total transportation cost and fixed cost of the selected p hubs with established capacity levels. A Lagrangian relaxation (LR) approach is proposed to solve the CSApHMPMC. The Lagrangian function that we formulated decomposed the original problem into smaller …


Toward An Engineering Discipline Of Warehouse Design, Leon Mcginnis, Timothy Sprock Jan 2016

Toward An Engineering Discipline Of Warehouse Design, Leon Mcginnis, Timothy Sprock

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

Warehouses today are complex dynamic engineered systems, incorporating automation, mechanization, equipment, fixtures, computers, networks, products and people, and they can support the flow of tens or hundreds of thousands of different items to enable fulfilling thousands or tens of thousands of orders daily. In that sense, they represent a design challenge that is not terribly different from the design of other complex dynamic engineered systems, such as a modern passenger airplane, an automobile, or a unique building. What is different is that the design of these other complex dynamic engineered systems typically follows some engineering design discipline. Here, we argue …


Monte Carlo Algorithm To Study Performance Parameters Of Shuttle Systems, Wolfgang Trummer, Dirk Jodin Jan 2016

Monte Carlo Algorithm To Study Performance Parameters Of Shuttle Systems, Wolfgang Trummer, Dirk Jodin

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

Shuttle systems provide alternative solutions in storage technology. Ma-terial flow analyses of these systems are extensive due to complex interac-tion of several shuttles and lift elements. Besides classic cycle time calcu-lation, it also requires advanced analyzing methods. At the Institute of Logistics Engineering (ITL), Graz University of Technology, an innovative, software-based approach has been developed to investigate the performance of shuttle systems. This approach is based on the Monte Carlo method. The software tool takes into account a variety of different systems and operating parameters to reflect operative behavior of shuttle systems.


Spare Parts On Demand Using Additive Manufacturing : A Simulation Model For Cost Evaluation., Stefan Jedeck Dec 2015

Spare Parts On Demand Using Additive Manufacturing : A Simulation Model For Cost Evaluation., Stefan Jedeck

Electronic Theses and Dissertations

Little is known about the impact of additive manufacturing in the spare part supply chain. A few studies are available, but they focus on specific parts and their applications only. A general model, which can be adapted to different applications, is nonexistent. This dissertation proposes a decision making framework that enables an interested practitioner/manager to decide whether using additive manufacturing to make spare parts on demand is economical when compared to conventional warehousing strategy. The framework consists of two major components: a general discrete event simulation model and a process of designing a wide range of simulation scenarios. The goal …


Inventory Management And Control "For A Cause", John Michael Miller May 2015

Inventory Management And Control "For A Cause", John Michael Miller

Graduate Theses and Dissertations

Companies today are changing the culture of business and beginning to involve more than just labor and money in overall decisions. Just as sustainability issues and humanitarian logistics are gaining popularity, so is the idea of using business to make a difference on society in addition to making a profit. As companies position themselves across the globe to make an impact, they employ people in third-world environments that create uncertainties on both the supply and demand sides. Also, the idea of strategically planning work with the goal of minimizing costs has been replaced by companies wanting to give more work …


Using The Triple Bottom Line To Select Sustainable Suppliers For A Major Oil And Gas Company, Pandarinath Adarsh Sunkari May 2015

Using The Triple Bottom Line To Select Sustainable Suppliers For A Major Oil And Gas Company, Pandarinath Adarsh Sunkari

Graduate Theses and Dissertations

Companies have primarily been focusing on the financial bottom line i.e., on increasing profits by increasing revenues and reducing costs. With high energy usage and environmental change posing threats to the environment and business operations, companies are now considering sustainability. Since some global suppliers have low cost labor, Social well-being and human development has also emerged as major goals of a company performing global operations. Focusing on these three goals is termed the "Triple Bottom Line" (TBL). We study and explore the TBL benefits that could be realized by an oil and gas company by focusing on sustainable suppliers. A …


Xiamen Port Bulk Cargo Collection And Distribution Systems Optimization, Juntao Cai Aug 2014

Xiamen Port Bulk Cargo Collection And Distribution Systems Optimization, Juntao Cai

World Maritime University Dissertations

No abstract provided.


Detailed Inventory Record Inaccuracy Analysis, Hayrettin Kaan Okyay May 2014

Detailed Inventory Record Inaccuracy Analysis, Hayrettin Kaan Okyay

Graduate Theses and Dissertations

This dissertation performs a methodical analysis to understand the behavior of inventory record inaccuracy (IRI) when it is influenced by demand, supply and lead time uncertainty in both online and offline retail environment separately. Additionally, this study identifies the susceptibility of the inventory systems towards IRI due to conventional perfect data visibility assumptions. Two different alternatives for such methods are presented and analyzed; the IRI resistance and the error control methods. The discussed methods effectively countered various aspects of IRI; the IRI resistance method performs better on stock-out and lost sales, whereas error control method keeps lower inventory. Furthermore, this …


Positioning Automated Guided Vehicles In A General Guide-Path Layout, Abraham Mendoza, Jose A. Ventura Jan 2014

Positioning Automated Guided Vehicles In A General Guide-Path Layout, Abraham Mendoza, Jose A. Ventura

13th IMHRC Proceedings (Cincinnati, Ohio. USA – 2014)

The locations of dwell points for idle vehicles in an automated guided vehicle (AGV) system determine the response times for pick-up requests and thus affect the performance of automated manufacturing systems. In this study, we address the problem of optimally locating dwell points for multiple AGVs in general guide-path layouts with the objective of minimizing the maximum response time in the system. We propose a mixed integer linear programming (MILP) formulation for the problem. We also develop a generic genetic algorithm (GA) to find near optimal solutions. The MILP model and GA procedure are illustrated using a two-dimensional grid layout …


Integrating Analysis Into A Warehouse Design Workflow, Leon Mcginnis, Timothy Sprock Jan 2014

Integrating Analysis Into A Warehouse Design Workflow, Leon Mcginnis, Timothy Sprock

13th IMHRC Proceedings (Cincinnati, Ohio. USA – 2014)

Supply chain analyses, including those related to material handling systems, are typically purpose-built to answer specific questions and therefore have many different implementations depending on the question, the instance data, and the solver. The purpose-built nature of these models makes it difficult to integrate them into an iterative design workflow. Despite the myriad analysis implementations, the fundamental structure of these systems and their problem domain remains unchanged, suggesting that perhaps analyses could be automatically generated on demand, given an appropriate specification of the particular system to be analyzed. We apply model-based systems engineering (MBSE) methodologies to explore this possibility in …


Throughput Analysis Of S/R Shuttle Systems, Georg Kartnig, Jörg Oser Jan 2014

Throughput Analysis Of S/R Shuttle Systems, Georg Kartnig, Jörg Oser

13th IMHRC Proceedings (Cincinnati, Ohio. USA – 2014)

Shuttle systems are used in high performance automated storage/retrieval unit load systems. Each storage level is serviced by one transfer car travelling in dual command operation. One buffer slot is located at both ends of each level. This decouples horizontal travel from vertical input/output moves, which in this case requires two independent vertical reciprocating lifts at each end of the aisle. Other systems work with only one lift used in lower throughput applications. The content of this paper is treated in the following sections starting with a problem definition and a literature survey. This is followed by a detailed functional …


Variation In Lifting Behavior During A Highly Repetitive Manual Material Task, Steven A. Lavender Jan 2014

Variation In Lifting Behavior During A Highly Repetitive Manual Material Task, Steven A. Lavender

13th IMHRC Proceedings (Cincinnati, Ohio. USA – 2014)

Presenters will provide.


Clickstream Big Data And “Delivery Before Order Making” Mode For Online Retailers, Yeming Yale Gong, Haoxuan Xu Jan 2014

Clickstream Big Data And “Delivery Before Order Making” Mode For Online Retailers, Yeming Yale Gong, Haoxuan Xu

13th IMHRC Proceedings (Cincinnati, Ohio. USA – 2014)

Our research is inspired by a leading online retailer using clickstream big data to estimate customer demand and then ship items to customers or hubs near customers by a mode of “delivery before order making” (DBOM) mode. Using clickstream data to obtain advance demand information in order quantities, we integrate the forecasting with a singleitem uncapacitated dynamic lot sizing problem in a rolling-horizon environment. Using the simulated clickstream data, we evaluate the performance of DBOM mode.


Comparing Industry And Academic Perspectives On Cross-Docking Operations, Paul Buijs, Iris F.A. Vis Jan 2014

Comparing Industry And Academic Perspectives On Cross-Docking Operations, Paul Buijs, Iris F.A. Vis

13th IMHRC Proceedings (Cincinnati, Ohio. USA – 2014)

This paper performs a comparative analysis on the industry and academic perspectives on cross-docking operations. Detailed descriptions are provided for three typical cross-dock settings by means of case illustrations. The purpose of these descriptions is to inspire break-through innovations in future cross-docking research by identifying constraints, decision problems, and performance indicators that are thoroughly anchored in current practice.


Comparison Of Alternative Configurations For Dense Warehousing Systems, Kevin R. Gue, G. Don Taylor Jan 2014

Comparison Of Alternative Configurations For Dense Warehousing Systems, Kevin R. Gue, G. Don Taylor

13th IMHRC Proceedings (Cincinnati, Ohio. USA – 2014)

In heavily constrained environments requiring very high density storage, traditional aisle-based warehousing may not provide viable options. One feasible manifestation of high density storage systems is the ‘puzzle-based’ system, in which unit loads are moved through the system via manipulation of empty (escort) locations to retrieve desired items. Another option would be the use of movable concentric rings, with escorts being utilized to enable lateral movements of unit loads between the rings. In this paper, the authors present analytical results to compare retrieval time performance for these two types of high density storage systems for randomly demanded items under various …


Analysis Of Class-Based Storage Strategies For The Mobile Shelf-Based Order Pick System, Shobhit Nigam, Debjit Roy, Rene De Koster, Ivo J.B.F. Adan Jan 2014

Analysis Of Class-Based Storage Strategies For The Mobile Shelf-Based Order Pick System, Shobhit Nigam, Debjit Roy, Rene De Koster, Ivo J.B.F. Adan

13th IMHRC Proceedings (Cincinnati, Ohio. USA – 2014)

Mobile Shelf-based Order Pick (MSOP) systems are gaining significant in- terest for e-commerce fulfillment due to their rapid deployment capability and dynamic organization of storage pods based on item demand profiles. In this research, we model the MSOP system with class-based storage strategies and alternate pod storage policies using multi-class closed queuing networks. We observe that though closest-open location pod storage policy do not allow to efficiently use the storage spaces in comparison to random location pod storage policy in an aisle, it increases the system throughput for all item classes.


A Two-Level Stochastic Model To Estimate Vessel Throughput Time, Debjit Roy, Vibhuti Dhingra, Rene De Koster Jan 2014

A Two-Level Stochastic Model To Estimate Vessel Throughput Time, Debjit Roy, Vibhuti Dhingra, Rene De Koster

13th IMHRC Proceedings (Cincinnati, Ohio. USA – 2014)

A good estimate of the vessel sojourn time is essential for better planning and scheduling Of container terminal resources,such as berth scheduling,quay crane(qc)assignment And scheduling,and fleet size planning. However,estimating the expected vessel so journ Time is a complex exercise because the time is dependent on several terminal operating Parameters such as the size of the vessel,the number of containers to be loaded and Unloaded,and the through put of the qcs. The through put of the qcs in turn depends On the type and number of transport vehicles,number of stack blocks,the topology of The vehicle travel path,the layout of the terminal,and …


An Empirical Study About The Effectiveness Of Lean Empowerment In Warehouses, Kai Furmans, Payam Dehdari Jan 2014

An Empirical Study About The Effectiveness Of Lean Empowerment In Warehouses, Kai Furmans, Payam Dehdari

13th IMHRC Proceedings (Cincinnati, Ohio. USA – 2014)

Lean Management is well established in production environments. Some empirical evidences are available which suggest that in production systems lean management achieves positive results. For warehousing, some works have already been done, which deal with the application and adaption of lean tools for usage in warehousing. In order to answer the question, whether the application of lean tools leads to a better performance however, no study is available today. Therefore, an empirical study has been conducted, where the effectiveness of lean empowerment has been tested and compared to the performance of warehouse, who continued to work as before.


Performance Comparison Of Various Order Picking Methods In Different Behavioral Contexts, Jelle De Vries, Rene De Koster, Daan Stam Jan 2014

Performance Comparison Of Various Order Picking Methods In Different Behavioral Contexts, Jelle De Vries, Rene De Koster, Daan Stam

13th IMHRC Proceedings (Cincinnati, Ohio. USA – 2014)

Three manual picker-to-parts order picking methods (parallel picking, zone picking, and dynamic zone picking) are employed in an experimental warehouse setup and compared in terms of productivity, quality, and job satisfaction. Participants worked in teams and were subject to either an individual- based, or a team-based incentive scheme. Furthermore, the influence of individual participants’ dominant regulatory focus (promotion or prevention) was taken into account. The outcomes show that in parallel picking an incentive system focused on individual performance is beneficial for productivity and quality compared to an incentive system focused on team performance, whereas team-based incentives are more productive in …


A Framework For The Robust Design Of Unit Load Storage Systems, Marc Goetschalckx, Edward Huang, Pratik Mital Jan 2014

A Framework For The Robust Design Of Unit Load Storage Systems, Marc Goetschalckx, Edward Huang, Pratik Mital

13th IMHRC Proceedings (Cincinnati, Ohio. USA – 2014)

The unit load storage assignment problem determines the assignment of a set of unit loads with known arrival and departure times to a set of unit storage locations in a warehouse. The material handling device(s) can carry at most one unit load at the time. In this research it is assumed that each of the storage locations can be accessed directly without load relocations or rearrangements and that the travel times between the storage locations and from and to the warehousing docks can be computed in advance. The objective is to minimize the total travel time of the material handling …


Modeling Conveyor Merges In Zone Picking Systems, Rene De Koster, Ivo J.B.F. Adan, Jacques Resing Jan 2014

Modeling Conveyor Merges In Zone Picking Systems, Rene De Koster, Ivo J.B.F. Adan, Jacques Resing

13th IMHRC Proceedings (Cincinnati, Ohio. USA – 2014)

In many order picking and sorting systems conveyors are used to transport products through the system and to merge multiple flows of products into one single flow. In practice, conveyor merges are potential points of congestion, and consequently can lead to a reduced throughput. In this paper, we study merges in a zone picking system. The performance of a zone picking system is, for a large part, determined by the performance of the merge locations. We model the system as a closed queueing network that describes the conveyor, the pick zones, and the merge locations. The resulting model does not …


A New Approach For Generating Facility Layouts Using An Algorithmic Approach, Volker Sadowsky, Christian Mosblech Jan 2014

A New Approach For Generating Facility Layouts Using An Algorithmic Approach, Volker Sadowsky, Christian Mosblech

13th IMHRC Proceedings (Cincinnati, Ohio. USA – 2014)

In this paper a new approach is described to automatically create layouts for material flow systems. The current research in progress aiming at adopting the methods and algorithms of the Electronic Design Automation to be used in logistics planning is presented. These methods are already applied to create microchips being multiple times more complex than material flow systems while following the same goal: Functional units have to be placed on a predefined area and are linked by connections weighted differently. This basic requirement can be applied to microchip designs as well as material flow systems. The common condition is to …


Setting Cutoff Times For Picking Systems With Capacity Degradation, Kevin R. Gue Jan 2014

Setting Cutoff Times For Picking Systems With Capacity Degradation, Kevin R. Gue

13th IMHRC Proceedings (Cincinnati, Ohio. USA – 2014)

In the new landscape of e-commerce distribution, firms must offer increasingly aggressive delivery promises and then make good on them. These promises often take the form of a cutoff time, such that orders placed before the cutoff time receive premium service (next-day, same-day, etc.) and those placed afterward do not. Later cutoff times are stronger, of course, but the fulfillment system might not be able to process the order before the deadline. How late is too late? We develop a deterministic model to answer this and related questions when the order fulfillment system batches orders for efficient picking operations and …


Robust Truckload Relay Network Design Under Demand Uncertainty, Hector A. Vergara, Zahra Mokhtari Jan 2014

Robust Truckload Relay Network Design Under Demand Uncertainty, Hector A. Vergara, Zahra Mokhtari

13th IMHRC Proceedings (Cincinnati, Ohio. USA – 2014)

This research addresses the issue of incorporating demand uncertainty in the strategic design of relay networks for truckload transportation. An existing composite variable mathematical model for the design of hybrid relay networks is extended by developing its robust counterpart. The proposed approach considers uncertainty in the number of truckloads to be dispatched between a pair of nodes in the network which is characterized by a symmetric interval around the expected demand value. A two-step heuristic approach is used to solve the robust model. Several numerical experiments are carried out to study the differences between the solutions obtained with the robust …


Experimental Validation Of Travel Time Models For Shuttle-Based Automated Storage And Retrieval System, Zaki Sari, Latefa Ghomri, Banu Y. Ekren, Tone Lerher Jan 2014

Experimental Validation Of Travel Time Models For Shuttle-Based Automated Storage And Retrieval System, Zaki Sari, Latefa Ghomri, Banu Y. Ekren, Tone Lerher

13th IMHRC Proceedings (Cincinnati, Ohio. USA – 2014)

In this paper, we aim to validate travel time models for single and dual command cycle displacements of lifts and shuttles in a shuttle-based automated storage and retrieval system (SBS/RS) by using experimental computer simulation. The models under consideration take into account acceleration and deceleration delays. We use ARENA 12 software for the simulation modeling. By simulation, we emulate the real functioning of the system. Therefore, we assume that the results from the ARENA simulation are equivalent to the onsite experimentation. Simulation results are very close to those obtained by analytical travel time models. This shows the high precision of …


Model And Algorithm For Supply Chain Analysis In Energy-Wood Industry, Thorsten Schmidt, Hannes Hahne Jan 2014

Model And Algorithm For Supply Chain Analysis In Energy-Wood Industry, Thorsten Schmidt, Hannes Hahne

13th IMHRC Proceedings (Cincinnati, Ohio. USA – 2014)

Short rotation coppices are a renewable energy concept based on renewable raw material. This paper proposes a model and calculation method which generates valid supply chains using quantified technological and infrastructural constraints.


Integrate Vehicle Routing And Truck Sequencing In Cross-Docking Operations, Ching-Jung Ting, Ting-Don Chen Jan 2014

Integrate Vehicle Routing And Truck Sequencing In Cross-Docking Operations, Ching-Jung Ting, Ting-Don Chen

13th IMHRC Proceedings (Cincinnati, Ohio. USA – 2014)

Cross-docking is a an important logistics strategy in which freight is unloaded from inbound vehicles and directly loaded into outbound vehicles, with little or no storage in between. This study considers a crossdocking system which combines the vehicle routing problem with crossdocking (VRPCD) for both inbound and outbound operations and truck sequencing problem at docks. The objective is to minimize the logistics center operation costs and transportation costs. We first formulated the integrated problem with a mixed integer programming model. Since VRPCD and sequencing problems are NP-hard, the integrated problem is also an NP-hard problem. We propose an ant colony …


The Cube Per Order Index Slotting Strategy, How Bad Can It Be?, Peter C. Schuur Jan 2014

The Cube Per Order Index Slotting Strategy, How Bad Can It Be?, Peter C. Schuur

13th IMHRC Proceedings (Cincinnati, Ohio. USA – 2014)

A well-known and frequently applied policy to assign stock keeping units (SKUs) to (dedicated) storage locations in a warehouse is the Cube per Order Index (COI) slotting strategy. Basically, COI stores an SKU based on how frequently it is picked per unit of stock space required. Fast movers are located close to the Input-Output points. For single command order picking, COI slotting is well-known to minimize order picking travel time. For multi command this is no longer true. An interesting question is: how bad can it be? In this paper we show that there is no limit to this badness. …


Development Of A Heuristics For A Criteria Based Planning Of Pallet Storage Systems, Detlef Spee, Michael Schmidt, Steffen Schieweck Jan 2014

Development Of A Heuristics For A Criteria Based Planning Of Pallet Storage Systems, Detlef Spee, Michael Schmidt, Steffen Schieweck

13th IMHRC Proceedings (Cincinnati, Ohio. USA – 2014)

Reproducible and quantitative reasoning as the foundation for high-quality planning processes evolves to be key to achieve high quality of speed for logistical processes. This article strives to fulfill this demand by developing a coherent heuristics for the planning of pallet storage systems. The heuristics uses quantitative approaches provided by the available literature. In case of nonexistent sources, the missing components are developed and integrated. To be applicable in an industrial environment, the comparison and assessment of the created implementation alternatives is mainly monetary based. The heuristics follows a modular structure to achieve adaptability and extensibility. It explicitly does not …


Data Model And Software Tools For Modeling Picking Operations, Jeffrey S. Smith Jan 2014

Data Model And Software Tools For Modeling Picking Operations, Jeffrey S. Smith

13th IMHRC Proceedings (Cincinnati, Ohio. USA – 2014)

Presenter will provide.