Resource-Constrained Scheduling for Multi-Robot Cooperative 3D Printing

2021 ◽  
pp. 1-29
Author(s):  
Laxmi Poudel ◽  
Wenchao Zhou ◽  
Zhenghui Sha
Keyword(s):  
3D Printing ◽  
Case Studies ◽  
Parallel Operation ◽  
Modified Genetic Algorithm ◽  
Novel Approach ◽  
And Performance ◽  
Printed Materials ◽  
Crossover And Mutation ◽  
Multi Robot

Abstract Cooperative 3D printing (C3DP) – a representative realization of cooperative manufacturing – is a novel approach that utilizes multiple mobile 3D printing robots for additive manufacturing. It makes the make-span much shorter compared to the traditional 3D printing due to parallel printing. In C3DP, collision-free scheduling is critical to the realization of cooperation and parallel operation among mobile printers. In the extant literature, there is a lack of methods to schedule multi-robot C3DP with limited resources. This study addresses this gap with two methods. The first method, dynamic dependency list algorithm (DDLA), uses constraint satisfaction to eliminate solutions that could result in collisions between robots and collisions between robots with already-printed materials. The second method, modified genetic algorithm (GA), uses chromosomes to represent chunk assignments and utilizes GA operators, such as the crossover and mutation, to generate diverse print schedules while maintaining the dependencies between chunks. Three case studies, including two large rectangular bars in different scales and a foldable SUV, are used to demonstrate the effectiveness and performance of the two methods. The results show that both methods can effectively generate valid print schedules using a specified number of robots while attempting to minimize the make-span. The results also show that both methods generate a print schedule with equal print time for the first two case studies with homogeneous chunks. In contrast, the modified GA outperforms the DDLA in the third case study, where the chunks are heterogeneous in volume and require different time to print.

Enabling Multi-Robot Cooperative Additive Manufacturing: Centralized vs. Decentralized Approaches

2021 ◽  
Author(s):  
Saivipulteja Elagandula ◽  
Laxmi Poudel ◽  
Wenchao Zhou ◽  
Zhenghui Sha
Keyword(s):  
3D Printing ◽  
Large Scale ◽  
Small Scale ◽  
Scale Problem ◽  
Problem Case ◽  
Large Scale Problem ◽  
First Case ◽  
Novel Approach ◽  
Multi Robot

Abstract This paper presents a decentralized approach based on a simple set of rules to carry out multi-robot cooperative 3D printing. Cooperative 3D printing is a novel approach to 3D printing that uses multiple mobile 3D printing robots to print a large part by dividing and assigning the part to multiple robots in parallel using the concept of chunk-based printing. The results obtained using the decentralized approach are then compared with those obtained from the centralized approach. Two case studies were performed to evaluate the performance of both approaches using makespan as the evaluation criterion. The first case is a small-scale problem with four printing robots and 20 chunks, whereas the second case study is a large-scale problem with ten printing robots and 200 chunks. The result shows that the centralized approach provides a better solution compared to the decentralized approach in both cases in terms of makespan. However, the gap between the solutions seems to shrink with the scale of the problem. While further study is required to verify this conclusion, the decrease in this gap indicates that the decentralized approach might compare favorably over the centralized approach for a large-scale problem in manufacturing using multiple mobile 3D printing robots. Additionally, the runtime for the large-scale problem (Case II) increases by 27-fold compared to the small-scale problem (Case I) for the centralized approach, whereas it only increased by less than 2-fold for the decentralized approach.

Interactive Models for Virtual Enterprises

2011 ◽  
pp. 316-333
Author(s):  
Håvard D. Jorgensen ◽  
John Krogstie
Keyword(s):  
Case Studies ◽  
Ad Hoc ◽  
Virtual Enterprises ◽  
Major Result ◽  
Research Projects ◽  
Model Driven ◽  
Visual Model ◽  
Novel Approach ◽  
Interactive Models ◽  
And Performance

This chapter presents a novel approach to the development, integration, and operation of virtual enterprises (VEs). The approach is based on the idea of interactive models. An interactive model is a visual model of enterprise aspects that can be viewed, traversed, analyzed, simulated, adapted, and executed by the participants of the VE. The approach has been developed in several research projects, where experiences from industrial case studies are used as a basis for validation and further enhancement. A major result of this work is the model-driven infrastructure that integrates and supports VEs. The main innovative contributions of this infrastructure include concurrent modelling, metamodelling, management and performance of work, integrated support for ad hoc and structured processes, and customizable model- and process-driven integration.

scholarly journals Exhibiting Music

Ethnologies ◽  
2017 ◽  
Vol 37 (1) ◽  
pp. 153-173
Author(s):  
Ameera Nimjee
Keyword(s):  
Case Studies ◽  
South Asian ◽  
Critical Inquiry ◽  
The South ◽  
Royal Ontario Museum ◽  
History Of ◽  
And Performance ◽  
Visual Engagement ◽  
Future Project

Museums have long been thought of as “quiet” spaces, in which visitors walk slowly through galleries to look at material cultures in glass cases. Music and sound have begun to pervade the quiet spaces of museums in the forms of aural installations and performance-based programs. They are no longer galleries for solely visual engagement, but loud spaces in which visitors and audiences listen to recordings, experience live performances, and participate by themselves singing and playing in workshops, classes, installations, and impromptu demonstrations. This article explores three case studies in exhibiting music. The first is the exhibition Ragamala: Garland of Melodies, which was on display at the Royal Ontario Museum and sought to demonstrate the fluidity between the South Asian arts. The second is an investigation of some of the formal and informal performance-based programming at the Aga Khan Museum. The last case study focuses on a future project, in which collectors of Indian audio cultures will submit contributions to help construct a history of sound in India. Each case study is motivated by a series of central questions: what constitutes “exhibiting music”? What are the broader implications of and consequences for exhibiting music in each case? How does exhibiting music in a museum impact a visitor’s experience? What kinds of new stories are told in exhibiting music and sound? The three case studies respond to these questions and provoke issues and possibilities for further critical inquiry. They show that museums are dynamic spaces with incredible potential to inspire multi-experiential engagement.

Interactive Models for Virtual Enterprises

2008 ◽  
pp. 715-730 ◽  
Author(s):  
Håvard D. Jorgensen ◽  
John Krogstie
Keyword(s):  
Case Studies ◽  
Ad Hoc ◽  
Virtual Enterprises ◽  
Major Result ◽  
Research Projects ◽  
Model Driven ◽  
Visual Model ◽  
Novel Approach ◽  
Interactive Models ◽  
And Performance

This chapter presents a novel approach to the development, integration, and operation of virtual enterprises (VEs). The approach is based on the idea of interactive models. An interactive model is a visual model of enterprise aspects that can be viewed, traversed, analyzed, simulated, adapted, and executed by the participants of the VE. The approach has been developed in several research projects, where experiences from industrial case studies are used as a basis for validation and further enhancement. A major result of this work is the model-driven infrastructure that integrates and supports VEs. The main innovative contributions of this infrastructure include concurrent modelling, metamodelling, management and performance of work, integrated support for ad hoc and structured processes, and customizable model- and process-driven integration.

New Approaches to the Study of the Regulation of Work

Living Wage ◽  
2019 ◽  
pp. 39-50
Author(s):  
Shelley Marshall
Keyword(s):  
Political Economy ◽  
Case Studies ◽  
Historical Institutionalism ◽  
Case Study Methodology ◽  
The Third ◽  
New Approaches ◽  
Novel Approach ◽  
Comprehensive Picture ◽  
Study Methodology

This book attempts to implement a novel approach to the study of the regulation of work in order to generate new insights into the ways that regulation can help to improve the lives of workers. It adopts historical institutionalism and political economy approaches to build a comprehensive picture of the varied dynamics that contributed to the growth of a precarious, informal workforce in four very different countries. The first section of Chapter 3 describes the overarching case-study methodology employed in this book. The second section describes the primary approach deployed in the case studies: historical institutionalism. The third section describes additional methods and disciplines used to put together stories that span macro and micro scales.

Computational Design of Scheduling Strategies for Multi-Robot Cooperative 3D Printing

2019 ◽  
Author(s):  
Laxmi Poudel ◽  
Wenchao Zhou ◽  
Zhenghui Sha
Keyword(s):  
3D Printing ◽  
Computational Design ◽  
Geometric Constraints ◽  
Computational Framework ◽  
Novel Approach ◽  
Dependency Tree ◽  
Scheduling Strategies ◽  
Evaluation Metric ◽  
Printing Time

Abstract Cooperative 3D printing (C3DP) is a novel approach to additive manufacturing, where multiple printhead-carrying mobile robots work together cooperatively to print a desired part. The core of C3DP is the chunk-based printing strategy in which the desired part is first split into smaller chunks, and then the chunks are assigned to individual printing robots. These robots will work on the chunks simultaneously and in a scheduled sequence until the entire part is complete. Though promising, C3DP lacks proper framework that enables automatic chunking and scheduling given the available number of robots. In this study, we develop a computational framework that can automatically generate print schedule for specified number of chunks. The framework contains 1) a random generator that creates random print schedule using adjacency matrix which represents directed dependency tree (DDT) structure of chunks; 2) a set of geometric constraints against which the randomly generated schedules will be checked for validation; and 3) a printing time evaluation metric for comparing the performance of all valid schedules. With the developed framework, we present a case study by printing a large rectangular plate which has dimensions beyond what traditional desktop printers can print. The study showcases that our computation framework can successfully generate a variety of scheduling strategies for collision-free C3DP without any human interventions.

Textile-integrated three-dimensional printed and embroidered structures for wearable wireless platforms

2018 ◽  
Vol 89 (4) ◽  
pp. 541-550 ◽  
Author(s):  
Han He ◽  
Xiaochen Chen ◽  
Leena Ukkonen ◽  
Johanna Virkki
Keyword(s):  
3D Printing ◽  
Radio Frequency Identification ◽  
Three Dimensional ◽  
Cyclic Strain ◽  
Elastic Band ◽  
Novel Approach ◽  
Frequency Identification ◽  
Permanent Effect ◽  
3D Printed ◽  
And Performance

In this paper, we present fabrication and performance evaluation of three-dimensional (3D) printed and embroidered textile-integrated passive ultra high frequency radio frequency identification (RFID) platforms. The antennas were manufactured by 3D printing a stretchable silver conductor directly on an elastic band. The electric and mechanical joint between the 3D printed antennas and microchips was formed by gluing with conductive epoxy glue, by printing the antenna directly on top of the microchip structure, and by embroidering with conductive yarn. Initially, all types of fabricated RFID tags achieved read ranges of 8–9 meters. Next, the components were tested for wetting as well as for harsh cyclic strain and bending. The immersing and cyclic bending slightly affected the performance of the tags. However, they did not stop the tags from working in an acceptable way, nor did they have any permanent effect. The epoxy-glued or 3D printed antenna–microchip interconnections were not able to endure harsh stretching. On the other hand, the tags with the embroidered antenna–microchip interconnections showed excellent wireless performance, both during and after a 100 strong stretching cycles. Thus, the novel approach of combining 3D printing and embroidery seems to be a promising way to fabricate textile-integrated wireless platforms.

scholarly journals Planning and performance measurement in higher education: three case studies of operational research application

2021 ◽  
Author(s):  
Juan G. Villegas ◽  
Carolina Castañeda P. ◽  
Eric Castañeda-Gómez
Keyword(s):  
Higher Education ◽  
Performance Measurement ◽  
Case Studies ◽  
Operational Research ◽  
Teaching Staff ◽  
Analysis Tool ◽  
Engineering School ◽  
New Curriculum ◽  
And Performance

In this work, we illustrate the application of a wide variety of Operations/operational research (OR) tools in higher education through three case studies based on practical applications conducted in the Engineering School of the Universidad de Antioquia. These case studies focus, respectively, on capacity planning, resource allocation, and performance measurement. In the first case study, we model and predict the flow of students enrolled in the industrial engineering program through the new curriculum using system dynamics and algebraic modeling of dropout rates, finding the number of sections for the courses, and the corresponding number of faculty positions needed to support the program structure. The second case study is a course covering model for the new curriculum that considers preferences and capacities of the teaching staff in an integer programming model, to find the uncovered courses of the new curriculum. Finally, the third case study presents a data envelopment analysis tool currently used to evaluate and rank the faculty of the Engineering School according to their teaching performance. The case studies presented in this work showcase how helpful OR tools are to rationalize the decision-making process in higher education institutions.

Patientenbezogene Komplexität in der Pflege – Kollektive Case Studies im Akutspital

Pflege ◽  
2018 ◽  
Vol 31 (5) ◽  
pp. 237-244 ◽  
Author(s):  
Caroline Gurtner ◽  
Rebecca Spirig ◽  
Diana Staudacher ◽  
Evelyn Huber
Keyword(s):  
Case Studies ◽  
Study Designs

Zusammenfassung. Hintergrund: Die patientenbezogene Komplexität der Pflege ist durch die Merkmale „Instabilität“, „Unsicherheit“ und „Variabilität“ definiert. Aufgrund der reduzierten Aufenthaltsdauer und der steigenden Zahl chronisch und mehrfach erkrankter Personen erhöht sich die Komplexität der Pflege. Ziel: In dieser Studie untersuchten wir das Phänomen patientenbezogener Komplexität aus Sicht von Pflegefachpersonen und Pflegeexpertinnen im Akutspital. Methode: Im Rahmen eines kollektiven Case-Study-Designs schätzten Pflegefachpersonen und Pflegeexpertinnen die Komplexität von Pflegesituationen mit einem Fragebogen ein. Danach befragten wir sie in Einzelinterviews zu ihrer Einschätzung. Mittels Within-Case-Analyse verdichteten wir die Daten induktiv zu Fallgeschichten. In der Cross-Case-Analyse verglichen wir die Fallgeschichten hinsichtlich deduktiv abgeleiteter Merkmale. Ergebnisse: Die Ausprägung der Komplexität hing in den vier Cases im Wesentlichen davon ab, ob klinische Probleme kontrollierbar und prognostizierbar waren. Je nach individuellen Ressourcen der Patientinnen und Patienten stieg bzw. sank die Komplexität. Schlussfolgerungen: Komplexe Patientensituationen fordern von Pflegefachpersonen Fachwissen, Erfahrung, kommunikative Kompetenzen sowie die Fähigkeit zur Reflexion. Berufsanfänger und Berufsanfängerinnen werden zur Entwicklung dieser Fähigkeiten idealerweise durch erfahrene Berufskolleginnen oder -kollegen unterstützt und beraten.

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