Operational Research Commons^™

Contingency Workload Demand Forecast Techniques For Cargo And Flying Hours, Calvin J. Bradshaw Iii

Theses and Dissertations

Accurate forecasting of contingency workload demand for USTRANSCOM (USTC) is a herculean effort. Transportation Working Capital Fund (TWCF) managers rely on various subject matters outside and within the combatant command to estimate future workload. Since rates are set annually, when TWCF activities use incorrect or incomplete projections of workload, this leads to erroneous price structures and misaligned customer billing rates. The USTC leadership lacks the ability to accurately forecast workload demand, which is a key driver for service provider rate-setting. As a result, some customers perceive spiked rates and seek service from other competitors, which generates lost revenue, customer dissatisfaction …

Application Of Smart Factory Design In Nuclear Energy Industry With Focus On Safety, Olivia Crasta, Cem Yilmaz

Engagement & Service-Learning Summit

No abstract provided.

A Simulation Model For Decision Support In Business Continuity Planning, Marissa Anne Mosunich

Master's Theses

Enterprises with a global supply network are at risk of lost revenue as a result of disruptive disasters at supplier locations. Various strategies exist for addressing this risk, and a variety of types of research has been done regarding the identification, assessment and response to the risk of disruption in a supply chain network.

This thesis establishes a decision model to support Business Continuity Planning at the first-tier supplier level. The decision model incorporates discrete-event simulation of supply chain networks (through Simio software), Monte Carlo simulation, and risk index optimization. After modeling disruption vulnerability in a supply chain network, costs …

Exploring Maintenance And Facility Operations Strategies For California Community Colleges, Virginia Parras Grande

Walden Dissertations and Doctoral Studies

California community college leaders are looking for strategies to sustain facilities and maintenance operations because the governor only approved the allocation of $87.5 million in the 2014-2015 Budget Act for facilities maintenance operations. Guided by the change and strategy theories, the purpose of this multicase study was to explore the strategies that a select group of college leaders have used to sustain or improve their facilities maintenance operations. The data collection process included a review of college planning documents and semistructured interviews with 10 senior administrators from 3 large California community colleges who have used strategies to address sustaining or …

Why Are All The Softies In Europe? A Discussion Of The Lack Of Penetration Of Soft Or In The Us, Andrew J. Collins, Patrick T. Hester

Engineering Management & Systems Engineering Faculty Publications

Soft Operations Research (OR) methods are used for a variety of real-world problems due to their focus on qualitative or interpretative problem formulation and analysis. Analysts use Soft Systems Methodology for problem structuring, drama theory for understanding conflicts, and morphological analysis for decision support. These techniques have an advantage over their quantitative counterparts because they can be used to tame wicked problems. So why is the use of soft OR not widespread in the US? In this paper, we discuss the systems and forces in place that limit soft OR within the US' higher education system and, by extension, the …

Using Mavt To Incorporate Public Perception When Choosing A Nuclear Fuel Cycle, Stephen Clement

Theses and Dissertations

Nuclear energy is a source of carbon free power. With many countries striving to make deep carbon cuts in their energy sectors, nuclear energy could be a large part of the solution. One of the main obstacles standing in the way of the use of nuclear energy is the issue of used nuclear fuel disposal. According to the NEI, the U.S. creates about 2000 metric tons of used nuclear fuel per year and has generated around 76,000 metric tons of used nuclear fuel over the last 4 decades. While there are technical problems that need to be solved, it is …

การพัฒนาแนวทางในการปรับยกระดับระบบบริหารคุณภาพจาก Iso 9001:2008 สู่ Iso 9001:2015, อัครพันธ์ จันทร์เสงี่ยม

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้มีจุดมุ่งหมายเพื่อประยุกต์การบริหารการเปลี่ยนแปลงในการปรับเปลี่ยนระบบบริหารคุณภาพ ISO 9000 ซึ่งปัจจุบันได้มีการปรับเปลี่ยนจากระบบบริหารคุณภาพ ISO 9001:2008 มาเป็นระบบบริหารคุณภาพ ISO 9001:2015 การเปลี่ยนแปลงนี้เป็นการเปลี่ยนแปลงที่เกิดจากภายนอกองค์กร (External Change) โดยองค์กรที่ได้รับการรับรองระบบ ISO หรือองค์กรที่ต้องการต่อใบรับรองต้องดำเนินการให้เหมาะสม งานวิจัยนี้เป็นการประยุกต์ใช้ขั้นตอนเพื่อการบริหารการเปลี่ยนแปลงให้บรรลุเป้าหมาย 8 ประการ ดังนี้ 1) สร้างสำนึกความจำเป็นเร่งด่วนที่ต้องเปลี่ยนแปลง 2) สร้างขุมพลังในการนำการเปลี่ยนแปลง 3) กำหนดวิสัยทัศน์และแผนการเปลี่ยนแปลงเชิงกลยุทธ์ 4) สื่อสารวิสัยทัศน์เพื่อสร้างการสนับสนุน 5) การดำเนินการเพื่อขจัดอุปสรรคของการเปลี่ยนแปลง 6) กำหนดเป้าหมายระยะสั้น และวางแผนเพื่อให้บรรลุเป้าหมาย 7) เสริมแรงการเปลี่ยนแปลงเพื่อการพัฒนาอย่างยั่งยืน 8) ปลูกฝังสิ่งที่เปลี่ยนแปลงให้เป็นส่วนหนึ่งของวัฒนธรรมบริษัท โดยแต่ละขั้นตอนได้นำเอาแนวคิดและทฤษฎีที่เกี่ยวกับการบริหารการเปลี่ยนแปลง เช่น แนวคิดเกี่ยวกับการต้านทานการเปลี่ยนแปลง (Force Field Analysis) การทดสอบความพร้อมในการเปลี่ยนแปลง (TROPICS Test) การศึกษาสภาพแวดล้อมองค์กร การวางแผนกลยุทธ์องค์กร การประเมินความเสี่ยง เป็นต้น มาประยุกต์ใช้เพื่อให้เกิดการเปลี่ยนแปลงได้อย่างมีประสิทธิผล และในงานวิจัยนี้ยังได้นำกระบวนการบริหารการเปลี่ยนแปลงของระบบบริหารคุณภาพนี้ ไปประยุกต์ใช้กับบริษัทกรณีศึกษาบริษัทผลิตโคมไฟ ซึ่งเป็นบริษัทผลิตโคมไฟลำดับแรกๆของประเทศ โดยผลของการประยุกต์ใช้ในครั้งนี้ส่งผลให้สามารถพัฒนากรอบการบริหารการเปลี่ยนแปลงเพื่อปรับเปลี่ยนระบบบริหารคุณภาพได้อย่างมีประสิทธิภาพ

A Scalable Algorithm For Locating Distribution Centers On Real Road Networks, Saeed Ghanbartehrani, Jose D. Porter

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

The median problem is a type of network location problem that aims at finding a node with the total minimum demand weighted distance to a set of demand nodes in a weighted graph. In this research, an algorithm for solving the median problem on real road networks is proposed. The proposed algorithm, referred to as the multi-threaded Dijkstra’s (MTD) algorithm, is then used to optimally locate Wal-Mart distribution centers on the 28-million node road network of the United States with the objective of minimizing the total demand weighted transportation cost. The resulting optimal location configuration of Wal-Mart distribution centers improves …

Evaluating Transaction Pairing Strategies For Vehicle-Based High-Density Storage Systems, Debjit Roy, Harit Joshie

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

Vehicle-based storage and retrieval systems present an attractive choice for distribution center automation because it provides the flexibility in managing demand fluctuations without affecting transaction throughput times. In this research, we contend that while dual-command cycles can reduce the vehicle travel times for processing transactions, it may not be the best policy for reducing transaction throughput times when transactions arrive at random time instants. We develop stochastic models to test the transaction throughput time performance with multiple pairing strategies and present operational insights.

Continuous Approximation Of Multi Cycle Time For Multi Aisles Automated Storage And Retrieval Systems., Yassine Boudghene Stambouli, Latefa Ghomri

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

Knowing that, in an automated storage and retrieval system, the travel time of the storage/retrieval machine is an important parameter which affects the whole system performances, several works were dedicated to its evaluation and its modeling, in single, dual and multi command. These models were proposed for different configurations of AS/RS; such as unit load, multi-aisles and Mobile Racks. These models are based mainly on a discrete approach and the analytical expressions represent the system functioning exactly. In this paper we present a general approach for analytical modeling of multi command cycle time by giving particularly the modeling of the …

Outsourced Storage And Fulfillment Facility To Enhance The Service Capabilities Of Shopping Mall Tenants, Zachary Montreuil, Mike Ogle

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

This paper proposes development of an Inventory and Fulfillment Center (IFC) that will provide a new range of outsourced, centralized storage and services for shopping mall tenants. The paper describes the competitive issues faced by shopping mall tenants, the requirements and features of a centralized, outsourced storage and fulfillment facility, and development of an agent-based model in AnyLogic® to demonstrate the concept. The range of research and business challenges introduced by this new concept are also presented.

New Design Guidelines For In-Plant Milk-Run Systems, Thorsten Schmidt, Ingolf Meinhardt, Frank Schulze

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

Tugger trains became a popular means of supply in material handling intensive production systems. In contrast to forklift trucks they interlink a supermarket with multiple delivery locations along a transport route in a milk-run. But the efficiency gain (higher transport capacity, reduced labor costs) has its price: Compared to forklift trucks, planning and dimensioning of in-plant milk-run systems is more complicated. The paper discusses features and drawbacks of a recent standardization approach of the Association of German Engineers (VDI) and highlights the variety of technical restrictions which have to be considered when a milkrun system is designed. It shows, that …

The Storage Replenishment Problem In Rectangular Warehouses, Haldun Sural, Claudia Archetti, Melih Celik

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

In warehouses, storage replenishment operations involve the transportation of items to capacitated item slots in forward storage area from reserve storage. These items are later picked from these slots as their demand arises. While order picking constitutes the majority of warehouse operating costs, replenishment operations might be as costly in warehouses where pick lists generally consist of only a few lines (e.g., order fulfillment warehouses). In this study, we consider the storage replenishment problem in a parallel-aisle warehouse, where replenishment and order picking operations are carried out in successive waves with time limits. The aim is to determine the item …

Performance Comparison Of Automated Warehouses Using Simulation, Nand Kishore Agrawal, Sunderesh S. Heragu, Chinnatat Methapatra

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

The purpose of this study is to compare the performance of two types of warehouses, both of which use autonomous vehicles (AVs). One warehouse uses movable racks (MR) for storing mini-loads, whereas the other uses fixed racks (FR). In general, warehouse automation not only increases the speed of the fulfillment process but also makes the picking process more accurate. We simulate three scenarios for the MR and FR systems using Simio. Four performance measures are considered for the comparison – the average order processing time (WR), the average utilization of AVs (U), the average order processing queue length (Nq) and …

Job Sequencing In A Miniload System, Lennart Baardman, Kees Jan Roodbergen

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

More and more warehouses shift towards the use of automated systems. One such system is a miniload system. In this system, a crane retrieves bins from their storage locations and brings the bins to the picking station, where a worker takes the requested products from the retrieved bins. After a product has been picked, the bin is put back by the crane in its original location. A buffer is present at the picking station to absorb fluctuations in speed between the picker and the crane. The problem of scheduling jobs in this system has received little attention in the literature. …

Dual-Tray Vertical Lift Modules For Fast Order Picking, Daria Battini, Martina Calzavara, Alessandro Persona, Fabio Sgarbossa

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

In the last years, new solutions for order picking systems have been developed both from industry and academics, especially for small items. They include innovative flexible automatic parts-to-picker systems and optimized picker-to-parts ones. One of these solutions consists in the use of Vertical Lift Modules (VLMs), a storage column in which small items are stored in extractable trays. In this paper, we study a new system composed by dual-tray VLMs where the operators perform picking and sorting activities. We propose several actions in order to improve the productivity of the entire system: 1) class based storage assignment of items inside …

Throughput Rate Of A Two-Worker Stochastic Bucket Brigade, Yossi Bukchin, Eran Hanany, Eugene Khmelnitsky

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

Work-sharing in production systems is a modern approach that improves throughput rate. Work is shifted between cross-trained workers in order to better balance the material now in the system. When a serial system is concerned, a common work-sharing approach is the Bucket-Brigade (BB), by which downstream workers sequentially take over items from adjacent upstream work- ers. When the workers are located from slowest-to-fastest and their speeds are deterministic, it is known that the line does not suffer from blockage or starvation, and achieves the maximal theoretical throughput rate (TR). Very little is known in the literature on stochastic self-balancing systems …

A Performance Measurement Framework And Solution Approach For The Integrated Facility Layout Problem With Uncertain Demand, Melih Celik, Begun Efeoglu, Haldun Sural

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

The integrated facility layout problem (IFLP) focuses on the simultaneous determination of the relative locations of multiple copies of capacitated equip- ment or machinery in a facility, as well as the material ow between these units. In this paper, we consider the IFLP in the existence of uncertain demand for the products of the facility. Motivated by the framework for next generation facility layouts by Benjaafar et al. (2002), we extend the approaches in the lit- erature for distributed facility layouts to the case of dynamic demand and the possibility of relayouts, and propose a heuristic solution approach to minimize …

Transport Items And Physical Internet Handling Boxes: A Comparison Framework Across Supply Chains, Eric Ballot, Benoit Montreuil

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

Pallets, cardboard boxes, and plastic crates are widely used tools to operate supply chains. As such they have many impacts on handling effort, shipment protection, transport mean utilization as well as repositioning and recycling efforts and they represent billions of assets spread all over the world. The historical and local origins of the designs and the sharing among many stakeholders do not ensure at all any kind of global optimization. The purpose of this paper is to define and explain a research effort to better measure and evaluate the efficiencies and inefficiencies for supply chain stakeholders for themselves and globally. …

Energy And Cycle Time Efficient Warehouse Design For Autonomous Vehicle-Based Storage And Retrieval System, Banu Yetkin Ekren, Tone Lerher

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

This study explores the best warehouse design for an autonomous vehicle based storage and retrieval system (AVS/RS) minimizing average energy consumption per transaction and average cycle time per transaction, simultaneously. In the design concept, we consider, rack design in terms of number of bays, number of tiers, number of aisles; number of resources, namely number of autonomous vehicles and lifts and; velocity profiles of lifts and autonomous vehicles in the AVS/RS. We completed 1,296 number of experiments in simulation to obtain Pareto solutions representing the “average energy consumption per transaction” and “average cycle time per transaction” trade-offs based on designs …