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Articles 8461 - 8490 of 13826

Full-Text Articles in Operations Research, Systems Engineering and Industrial Engineering

Development Of An Instrument To Assess Capacity For Systems Thinking, Kaitlynn M. Castelle, Raed M. Jaradat Jan 2016

Development Of An Instrument To Assess Capacity For Systems Thinking, Kaitlynn M. Castelle, Raed M. Jaradat

Engineering Management & Systems Engineering Faculty Publications

With the rapid growth and integration in technology and information, the behavior and structure of complex systems presents escalating challenges. Complex systems are marked by high level of ambiguity, uncertainty, and emergence. These conditions impose challenges and difficulties for practitioners responsible to successfully manage and design complex systems. There is a fundamental need to have a cadre of individuals who are capable of dealing with increasingly complex systems and their problems. One response is Systems Thinking, which can provide a holistic thinking paradigm that opens new channels and opportunities to think differently about complex systems as a whole unit. This …

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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 Jan 2016

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 …

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Systemic Analysis Of Complex System Governance For Acquisition, Charles B. Keating, Joseph M. Bradley, Polinpapilinho F. Katina Jan 2016

Systemic Analysis Of Complex System Governance For Acquisition, Charles B. Keating, Joseph M. Bradley, Polinpapilinho F. Katina

Engineering Management & Systems Engineering Faculty Publications

The purpose of this paper is to explore Complex System Governance (CSG) issues related to systemic analysis of acquisition systems. CSG is an emerging field focused on the design, execution, and evolution of the functions necessary to provide continued system performance (stability) in the midst of incessant turbulence and increasing complexity. Integral to this field is the necessity to engage systems to address behavior or performance that is inconsistent with that which is desired. Systemic analysis for CSG serves to examine a system to discover fundamental system issues (e.g. acquisition). Arguably, system acquisition has an unremarkable record of success, ranging …

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Modeling Resilience In System Of Systems Architecture, Paulette Acheson, Cihan H. Dagli Jan 2016

Modeling Resilience In System Of Systems Architecture, Paulette Acheson, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

System of Systems (SoS) can be represented by the SoS architecture which defines the constituent systems and their interfaces. SoS delivers capabilities beyond what the systems working independently can provide. Resiliency of the SoS is becoming increasingly more important and necessary for mission success. Resiliency can be defined as the ability of the SoS architecture to defend against emerging threats. This defense means adapting the SoS architecture to handle the new threat. As a new threat is uncovered, the SoS architecture evolves to a new SoS architecture resilient to the new threat. This paper presents a novel approach to modeling …

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Stimulus And Optode Placement Effects On Functional Near-Infrared Spectroscopy Of Visual Cortex, Nasser H. Kashou, Brenna M. Giacherio Jan 2016

Stimulus And Optode Placement Effects On Functional Near-Infrared Spectroscopy Of Visual Cortex, Nasser H. Kashou, Brenna M. Giacherio

Biomedical, Industrial & Human Factors Engineering Faculty Publications

Functional near-infrared spectroscopy has yet to be implemented as a stand-alone technique within an ophthalmology clinical setting, despite its promising advantages. The present study aims to further investigate reliability of visual cortical signals. This was achieved by: (1) assessing the effects of optode placements using the 10–20 International System of Electrode Placement consisting of 28 channels, (2) determining effects of stimulus size on response, and (3) evaluating response variability as a result of cap placement across three sessions. Ten participants with mean age 23.8 4.8 years (five male) and varying types of hair color and thickness were recruited. Visual stimuli …

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Hand-Grasping And Finger Tapping Induced Similar Functional Near-Infrared Spectroscopy Cortical Responses, Nasser H. Kashou, Brenna M. Giacherio, Ramzi W. Nahhas, Sudarshan R. Jadcherla Jan 2016

Hand-Grasping And Finger Tapping Induced Similar Functional Near-Infrared Spectroscopy Cortical Responses, Nasser H. Kashou, Brenna M. Giacherio, Ramzi W. Nahhas, Sudarshan R. Jadcherla

Biomedical, Industrial & Human Factors Engineering Faculty Publications

Despite promising advantages such as low cost and portability of functional near-infrared spectroscopy (fNIRS), it has yet to be widely implemented outside of basic research. Specifically, fNIRS has yet to be proven as a standalone tool within a clinical setting. The objective of this study was to assess hemodynamic concentration changes at the primary and premotor motor cortices as a result of simple whole-hand grasping and sequential finger-opposition (tapping) tasks. These tasks were repeated over 3 days in a randomized manner. Ten healthy young adults (23.8 4.8 years) participated in the study. Quantitatively, no statistically significant differences were discovered between …

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Finite Element Analysis Of Superior C3 Cervical Vertebra Endplate And Cancellous Core Under Static Loads, Isaac Mabe, Tarun Goswami Jan 2016

Finite Element Analysis Of Superior C3 Cervical Vertebra Endplate And Cancellous Core Under Static Loads, Isaac Mabe, Tarun Goswami

Biomedical, Industrial & Human Factors Engineering Faculty Publications

Subsidence is a type of failure associated with implanted cervical cages or artificial intervertebral discs. It is defined as a loss of postoperative disc height. Actuarial rates show a risk of subsidence at 16 weeks at 70.7 percent. This study examines the changes in the vertebral endplate morphology and the resulting effect on the stresses developed in the endplate and in the vertebral core. A three-dimensional linear elastic model was created from computed tomographic (CT) scans and material properties were assigned according to various studies. Particular care was taken in the superior endplate that was modeled according to experimental measurements. …

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Analysis Of A Clinically Failed, Mechanically Intact, Hemi-Toe Implant, Swetha Varadharajan, Richard T. Laughlin, Tarun Goswami Jan 2016

Analysis Of A Clinically Failed, Mechanically Intact, Hemi-Toe Implant, Swetha Varadharajan, Richard T. Laughlin, Tarun Goswami

Biomedical, Industrial & Human Factors Engineering Faculty Publications

In this case study a clinically failed, mechanically intact, hemi-toe device was investigated. The clinical indication of the failure constitutes radiolucent line indicating loosening of the implant and possible interactions among the bone-implant initiated by osteolysis may become a factor, producing pain, inflammatory reactions, deformity and discomfort. The patient file was not available to determine these parameters. The device was titanium coated, Cobalt Chromium alloy used for making hemi-toe. Degeneration of hemi implant was due to spalling of the coating from the surface, causing loosening of stem from bone. However, pre-removal X-ray films were not available to confirm. Mechanism by …

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A Framework For Quantifying And Managing Overcrowding In Healthcare Facilities, Abdulrahman Albar Jan 2016

A Framework For Quantifying And Managing Overcrowding In Healthcare Facilities, Abdulrahman Albar

Electronic Theses and Dissertations

Emergency Departments (EDs) represent a crucial component of any healthcare infrastructure. In today's world, healthcare systems face growing challenges in delivering efficient and time-sensitive emergency care services to communities. Overcrowding within EDs represents one of the most significant challenges for healthcare quality that adversely impacts clinical outcomes, patient safety, and overall satisfaction. Research in this area has resulted in creating several ED crowding indices, such as National Emergency Department Overcrowding Scale (NEDOCS) and Emergency Department Work Index (EDWIN) that have been developed to provide measures aimed at mitigating overcrowding. Recently, efforts made by researchers to examine the validity and reproducibility …

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A Neuroergonomics Study Of Brain Eeg's Activity During Manual Lifting Tasks, Awad Aljuaid Jan 2016

A Neuroergonomics Study Of Brain Eeg's Activity During Manual Lifting Tasks, Awad Aljuaid

Electronic Theses and Dissertations

Electroencephalography (EEG) has been shown to be a reliable tool in neuroergonomics studies due to the relatively low cost of brain data collection and limited body invasion. The application of EEG frequency bands (including theta, alpha and beta), enjoyed a wide range of interest in physical and cognitive ergonomics. The psychophysical approach has been used for decades to improve safe work practices by understanding human limitations in manual materials handling. The main objective of this research project was to study the brain's EEG activity expressed by the power spectral density during manual lifting tasks related to: 1) the maximum acceptable …

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Cyber-Physical Systems: Complex System Governance As An Integrating Construct, Polinpapilinho F. Katina, Charles B. Keating, Adrian V. Gheorghe Jan 2016

Cyber-Physical Systems: Complex System Governance As An Integrating Construct, Polinpapilinho F. Katina, Charles B. Keating, Adrian V. Gheorghe

Engineering Management & Systems Engineering Faculty Publications

This paper examines contributions of Complex System Governance (CSG) as an integrating construct for the emerging fields of critical cyber-physical systems (CPS). CPS is concerned with physical entities that are controlled by computational elements. The field is relatively new, emerging, and also somewhat fragmented in development. There are multiple agencies, entities, and activities being undertaken to address a nexus of emerging issues (e.g., cybersecurity) in critical infrastructures. However, the development of critical CPS, as a field, albeit with good intentions and efforts, appears to be largely ‘self-organizing.’ In response, we suggest CSG as an organizing construct capable of provided a …

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Using Mavt To Incorporate Public Perception When Choosing A Nuclear Fuel Cycle, Stephen Clement Jan 2016

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 …

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การพัฒนาแนวทางในการปรับยกระดับระบบบริหารคุณภาพจาก Iso 9001:2008 สู่ Iso 9001:2015, อัครพันธ์ จันทร์เสงี่ยม Jan 2016

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

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A Scalable Algorithm For Locating Distribution Centers On Real Road Networks, Saeed Ghanbartehrani, Jose D. Porter Jan 2016

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 …

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Evaluating Transaction Pairing Strategies For Vehicle-Based High-Density Storage Systems, Debjit Roy, Harit Joshie Jan 2016

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.

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Continuous Approximation Of Multi Cycle Time For Multi Aisles Automated Storage And Retrieval Systems., Yassine Boudghene Stambouli, Latefa Ghomri Jan 2016

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 …

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Outsourced Storage And Fulfillment Facility To Enhance The Service Capabilities Of Shopping Mall Tenants, Zachary Montreuil, Mike Ogle Jan 2016

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.

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New Design Guidelines For In-Plant Milk-Run Systems, Thorsten Schmidt, Ingolf Meinhardt, Frank Schulze Jan 2016

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 …

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The Storage Replenishment Problem In Rectangular Warehouses, Haldun Sural, Claudia Archetti, Melih Celik Jan 2016

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 …

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Performance Comparison Of Automated Warehouses Using Simulation, Nand Kishore Agrawal, Sunderesh S. Heragu, Chinnatat Methapatra Jan 2016

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 …

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Job Sequencing In A Miniload System, Lennart Baardman, Kees Jan Roodbergen Jan 2016

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. …

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Dual-Tray Vertical Lift Modules For Fast Order Picking, Daria Battini, Martina Calzavara, Alessandro Persona, Fabio Sgarbossa Jan 2016

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 …

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Throughput Rate Of A Two-Worker Stochastic Bucket Brigade, Yossi Bukchin, Eran Hanany, Eugene Khmelnitsky Jan 2016

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 …

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A Performance Measurement Framework And Solution Approach For The Integrated Facility Layout Problem With Uncertain Demand, Melih Celik, Begun Efeoglu, Haldun Sural Jan 2016

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 …

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Transport Items And Physical Internet Handling Boxes: A Comparison Framework Across Supply Chains, Eric Ballot, Benoit Montreuil Jan 2016

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. …

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Energy And Cycle Time Efficient Warehouse Design For Autonomous Vehicle-Based Storage And Retrieval System, Banu Yetkin Ekren, Tone Lerher Jan 2016

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 …

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Determination Of Cycle Times For Double Deep Storage Systems Using A Dual Capacity Handling Device, Katharina Dorr Jan 2016

Determination Of Cycle Times For Double Deep Storage Systems Using A Dual Capacity Handling Device, Katharina Dorr

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

Double deep storage is an efficient method to improve space utilization in warehouses. Contrary to intuition, it also can be efficient when considering retrieval times, since the aisles of a warehouse with double deep storage may be shorter than comparable warehouses with single deep storage. AS/RS-machines equipped with two load-handling units might further improve the situation, since two storage units (for instance pallets or cases) can be stored and retrieved, effectively allowing quadruple command cycles, bringing in total two storage units into the aisle and retrieving two storage units at the same time. In this paper, we present a method …

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A Simulation Model To Evaluate The Layout For Block Stacking Warehouses, Shahab Derhami, Jeffrey S. Smith, Kevin R. Gue Jan 2016

A Simulation Model To Evaluate The Layout For Block Stacking Warehouses, Shahab Derhami, Jeffrey S. Smith, Kevin R. Gue

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

Storing pallets of Stock Keeping Units (SKU's) on top of another in lanes on a warehouse floor is known as block stacking. This storage system is widely used in manufactoring systems and distribution centers. The arrangement of lanes in the layout of this system significantly impacts utilization of the storage space and transportation costs. Existing research that studies the layout for this system focuses exclusively on determining the optimal lane depth with respect to space utilization and ignores transportation costs. In this study, we develop a stimulation model that computes several performance metrics to evaluate both of these objectives for …

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A Novel Approach To Analyze Inventory Allocation Decisions In Robotic Mobile Fulfillment Systems, Tim Lamballais, Debjit Roy, M.B.M De Koster Jan 2016

A Novel Approach To Analyze Inventory Allocation Decisions In Robotic Mobile Fulfillment Systems, Tim Lamballais, Debjit Roy, M.B.M De Koster

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

The Robotic Mobile Fulfillment System is a newly developed automated, parts-to-picker material handling system. Storage shelves, also known as inventory pods, are moved by robots between the storage area and the workstations, which means that they can be continually repositioned during operations. This paper develops a queueing model for optimizing three key decision variables: (1) the number of pods per product (2) the ratio of the number of pick to the number of replenishment stations, and (3) the replenishment level per pod. We show that too few or too many pods per product leads to unnecessarily long order throughput times, …

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Simulation-Based Energy And Cycle Time Analysis Of Shuttle-Based Storage And Retrieval System, Tone Lerher, Banu Yetkin Ekren, Anil Akpunar Jan 2016

Simulation-Based Energy And Cycle Time Analysis Of Shuttle-Based Storage And Retrieval System, Tone Lerher, Banu Yetkin Ekren, Anil Akpunar

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

This study explores the best warehouse design for shuttle-based storage and retrieval system (SBS/RS) minimizing average energy consumption per transaction and average cycle time per transaction, simultaneously. For that we provided average energy consumption per transaction versus average cycle time per transaction graphs, for different design scenarios of the studied SBS/RS warehouse. In the design concept, we considered, rack design in terms of number of bays, number of tiers, number of aisles, as well as velocity profiles of lifts in the system. We completed 144 number of experiments by simulation to see the trade-offs based on the design scenarios and …

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