1,720,987 research outputs found
Kit Preparation with Cobot-Supported Sorting in Mixed Model Assembly
Full text linkKitting is a common approach of materials supply with mixed-model assembly, by which components are supplied to the assembly process in pre-sorted kits. With kitting, the kit preparation is a labour intensive process and order batching is often applied to enhance efficiency. Here, improved quality and efficiency by means of automation is desirable, but knowledge of the potential of collaborative robots to support kit preparation with order batching is lacking. The purpose of this paper is to identify the potential of cobots to support time-efficient kit preparation with order batching, when the pick task is performed manually and a cobot carries out the sort task. A modelling approach is applied with experimental data from laboratory experiments to compare the cycle time between fully manual and cobot-supported kit preparation with order batching. The findings suggest that a cobot-supported sort task leads to a comparable average cycle time, with less variability of the cycle time, when compared to the fully manual setup. The paper contributes several insights on the application of cobots to support kit preparation, and the model developed in the paper can be used by practitioners to assess the potential of cobots to support their processes for kit preparation. (C) 2019, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved
Kit preparation for mixed-model assembly: efficiency impact of confirmation methods
No full textPurpose – Confirmations are applied in kit preparation for mixed-model assembly to promote quality, but research that explains the impact on time efficiency has been lacking. The purpose of this paper is to determine the extent to which the type of confirmation method relates to time-efficient kit preparation when order batching is applied.Design/methodology/approach – An industrially relevant laboratory experiment is applied, simulating kit preparation with order batching for mixed-model assembly. The time efficiency is studied as associated with four confirmation methods – barcode ring scanner, button presses, voice commands and RFID-reading wristbands – when applied as pick-from and place-to confirmation. Furthermore, the paper also considers the quality outcome.Findings – Efficiency is promoted by methods that minimise interrupting the picker’s motions when performing pick-from confirmations and with methods that allow each hand to place components and perform place-to confirmations simultaneously – here represented by button presses and RFID-reading wristbands. Moreover, combining various methods for the tasks of pick-from or place-to confirmation can benefit efficiency.Research limitations/implications – Pickers at an early stage of the learning curve (one shift of training) were considered.Practical implications – The findings promote the customised applications of picking information systems in industry.Social implications – Combining various methods for the tasks of pick-from and place-to confirmation can provide more fitting applications that better align with the picker’s preferences.Originality/value – Combinations of various methods when applied as either pick-from or place-to confirmation, or both, are studied
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Materials preparation handbook Guidelines for choice of materials preparation design
Full text linkMaterials preparation is increasingly applied with mixed model assembly as means of support to the assembly process. With materials preparation, components are sorted at a picking area before reaching the assembly process. This is required when, for example, materials are supplied to the assembly process by kitting or part sequencing approaches. When presented to the assembler, prepared materials shorten the walking distance and simplifies the search for components in the assembly process compared to other approaches, and promotes the assembly’s performance. However, to best support the assembly process, the materials preparation must be carried out cost effectively with satisfactory quality, flexibility, productivity, and ergonomics, with respect to the current context. Previous research and practitioner experience has shown that the materials preparation design can greatly affect the performance outcome. There is a multitude of decisions involved with the choice of materials preparation design, and choosing an appropriate design that fulfils the performance expectations with respect to the context can be a complicated task. The aim of this handbook is to present previous research and practitioner knowledge regarding how to design materials preparation processes in assembly systems, and to consolidate the various decisions associated with materials preparation design into a framework that can be applied by practitioners and academics dealing with materials preparation design.The handbook presents the various aspects related to the design, context and performance of materials preparation, in form of guidelines for how these aspects may be considered in the design process. The guidelines focus on how to design manual picking processes where a single worker carries out the picking work. The context in which the guidelines are presented is mixed model assembly, but much of the content would also find applicability in other contexts, for example warehouse order picking in distribution or e-commerce settings. The guidelines presented in the handbook are based on the outcome of a research project which was a joint venture between academia and industry, and included partners from both the manufacturing and distribution sectors. The perspective taken on the design problem of materials preparation processes in the current handbook is to view the design as a set of design variables, for which the aim is to find suitable settings to achieve the desired performance outcome. For each design variable, a number of typical options are presented and the effects on the performance, and the influence of the context when making the choice, are explored and discussed based on the findings from the research project. The first chapter of the handbook introduces the scope and aim of the book, and provides an overview of the chapters to come. In the second, third and fourth chapters, the various aspects and typical options with respect to the materials preparation performance (chapter 2), context (chapter 3), and the design (chapter 4) are presented and discussed. In the fifth chapter, a design process is outlined and guidelines for achieving the performance objectives by means of the design and with respect to the context are provided. In the sixth chapter, a set of examples of materials preparation design from industry and from the research studies are presented to give a hands-on view of what can be done and what should be avoided. In the final chapter, the book is concluded along with an outlook of future opportunities and challenges related to materials preparation design.This handbook is intended for readers interested about the design of picking systems. The book is written for readers from both academia, for example researchers or students, and from industry, for example engineers, managers or consultants. The book’s structure permits easy access to referential reading about various aspects of the materials preparation design, and although the book certainly could be read from start to finish, it would serve the reader to start with a set of questions already in mind. Materials preparation is carried out for supporting the assembly process, and this book supports the decision process when choosing a materials preparation design
Materials Handling in Production Systems: Design and Performance of Kit Preparation [Elektronisk resurs]
No full textThis thesis focuses on processes for kit preparation, which are applied with the materials supply principle of kitting in production systems for mixed-model assembly. With kitting, assembly processes are supplied with portions of pre-sorted components, and each portion makes up a kit that holds the components needed for one assembly object at one or several assembly processes. When kitting is applied, picking activities, which are otherwise performed at assembly processes, are instead carried out in a process for kit preparation. Kit preparation involves collecting components designated for a particular assembly object into a single unit load that is delivered to assembly. Kitting is widely seen as beneficial for quality and flexibility in assembly processes when there are a large variety of components. Performance effects in assembly processes normally associated with kitting largely depend on the performance of kit preparation. Previous research indicates that a picking system’s design greatly impacts its performance. While research that has dealt with kit preparation points out several design aspects that can affect its performance, the available knowledge is far from exhaustive. The purpose of this thesis is to contribute to the knowledge of how kit preparation design aspects govern kit preparation performance. Case research, experiments, and modelling have been used to study how flexibility, kit quality and man-hour efficiency are affected by kit preparation design aspects related to work organisation, layout, policies, packaging, equipment, picking information, automation and control. Two case research studies respectively address kit preparation flexibility and kit quality, identifying how kit preparation design aspects can be configured to support these two performance areas. Two experiments focus on how picking information systems and confirmation methods affect kit preparation man-hour efficiency. One modelling study focuses on how collaborative robots can support man-hour efficient kit preparation. Through involvement in three research projects and an extensive review of the literature, this research has been guided by the needs of industry and by previously established knowledge. This thesis contributes to theory and to practice in the form of knowledge about relationships between kit preparation design aspects and the performance areas flexibility, kit quality and manhour efficiency. The theoretical contribution consists of building upon and underpinning the limited knowledge about the topic that has been previously available, while also adding new knowledge. This includes, for example, glasses with integrated computer displays, RFID-scanning wristbands, and collaborative robots, and how they are linked to kit preparation performance. The practical contribution consists of concise yet holistic descriptions of relationships between kit preparation design and performance, which industry can readily adopt with some consideration to the situation’s characteristics
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