Humans:the missing link in manufacturing simulation?

Computer based discrete event simulation (DES) is one of the most commonly used aids for the design of automotive manufacturing systems. However, DES tools represent machines in extensive detail, while only representing workers as simple resources. This presents a problem when modelling systems with a highly manual work content, such as an assembly line. This paper describes research at Cranfield University, in collaboration with the Ford Motor Company, founded on the assumption that human variation is the cause of a large percentage of the disparity between simulation predictions and real world performance. The research aims to improve the accuracy and reliability of simulation prediction by including models of human factors.

Analytical approximations to predict performance measures of manufacturing systems with job failures and parallel processing

Parallel processing is prevalent in many manufacturing and service systems. Many manufactured products are built and assembled from several components fabricated in parallel lines. An example of this manufacturing system configuration is observed at a manufacturing facility equipped to assemble and test web servers. Characteristics of a typical web server assembly line are: multiple products, job circulation, and paralleling processing. The primary objective of this research was to develop analytical approximations to predict performance measures of manufacturing systems with job failures and parallel processing. The analytical formulations extend previous queueing models used in assembly manufacturing systems in that they can handle serial and different configurations of paralleling processing with multiple product classes, and job circulation due to random part failures. In addition, appropriate correction terms via regression analysis were added to the approximations in order to minimize the gap in the error between the analytical approximation and the simulation models. Markovian and general type manufacturing systems, with multiple product classes, job circulation due to failures, and fork and join systems to model parallel processing were studied. In the Markovian and general case, the approximations without correction terms performed quite well for one and two product problem instances. However, it was observed that the flow time error increased as the number of products and net traffic intensity increased. Therefore, correction terms for single and fork-join stations were developed via regression analysis to deal with more than two products. The numerical comparisons showed that the approximations perform remarkably well when the corrections factors were used in the approximations. In general, the average flow time error was reduced from 38.19% to 5.59% in the Markovian case, and from 26.39% to 7.23% in the general case. All the equations stated in the analytical formulations were implemented as a set of Matlab scripts. By using this set, operations managers of web server assembly lines, manufacturing or other service systems with similar characteristics can estimate different system performance measures, and make judicious decisions - especially setting delivery due dates, capacity planning, and bottleneck mitigation, among others.

Analytical Approximations to Predict Performance Measures of Manufacturing Systems with Job Failures and Parallel Processing

Parallel processing is prevalent in many manufacturing and service systems. Many manufactured products are built and assembled from several components fabricated in parallel lines. An example of this manufacturing system configuration is observed at a manufacturing facility equipped to assemble and test web servers. Characteristics of a typical web server assembly line are: multiple products, job circulation, and paralleling processing. The primary objective of this research was to develop analytical approximations to predict performance measures of manufacturing systems with job failures and parallel processing. The analytical formulations extend previous queueing models used in assembly manufacturing systems in that they can handle serial and different configurations of paralleling processing with multiple product classes, and job circulation due to random part failures. In addition, appropriate correction terms via regression analysis were added to the approximations in order to minimize the gap in the error between the analytical approximation and the simulation models. Markovian and general type manufacturing systems, with multiple product classes, job circulation due to failures, and fork and join systems to model parallel processing were studied. In the Markovian and general case, the approximations without correction terms performed quite well for one and two product problem instances. However, it was observed that the flow time error increased as the number of products and net traffic intensity increased. Therefore, correction terms for single and fork-join stations were developed via regression analysis to deal with more than two products. The numerical comparisons showed that the approximations perform remarkably well when the corrections factors were used in the approximations. In general, the average flow time error was reduced from 38.19% to 5.59% in the Markovian case, and from 26.39% to 7.23% in the general case. All the equations stated in the analytical formulations were implemented as a set of Matlab scripts. By using this set, operations managers of web server assembly lines, manufacturing or other service systems with similar characteristics can estimate different system performance measures, and make judicious decisions - especially setting delivery due dates, capacity planning, and bottleneck mitigation, among others.

Melhoria de uma linha de montagem pela aplicação da filosofia Lean

Este relatório descreve o desenvolvimento de um projecto de melhoria numa linha de montagem de autocarros, numa das empresas do Grupo Salvador Caetano: a CaetanoBus. Sustentado teoricamente pelos pressupostos da filosofia lean, o projecto visou sobretudo uma organização mais eficiente dos recursos humanos e materiais, de modo a alcançar uma redução do lead time e, por conseguinte, uma diminuição simultânea de desperdícios associados ao processo e do número de colaboradores afectos a determinado modelo de autocarro. A metodologia adoptada envolveu fundamentalmente operações relativas ao estudo de tempos, balanceamento e estabelecimento de standard works. Por outro lado, outros conceitos associados ao lean, como kaizen e yamazum chart, integraram igualmente a linha estruturante de pensamento que orientou o campo das acções. Um plano de melhorias baseado no uso das ferramentas lean sugere ganhos produtivos, muito embora o término da produção do modelo, alvo de análise, tivesse impedido a sua confirmação prática nesta matéria.

Desenvolvimento de solenóides para eletroválvulas hidráulicas

Os solenóides para eletroválvulas, em conjunto com outros produtos e equipamentos, permitem a automação dos sistemas de distribuição de águas não potáveis, como, por exemplo, em sistemas de rega. Deste modo é possível controlar diversos parâmetros, como o caudal e a pressão da água que passa na válvula, podendo estes ser fiscalizados à distância. Neste trabalho, foram desenvolvidos solenóides para acoplar a válvulas que se destinam à rega agrícola, comercializadas pela empresa JPrior, Fábrica de Plásticos, Lda. Para o efeito, foram definidos vários processos necessários para a criação de uma linha piloto de pré industrialização destes dispositivos. Etapas como a conceção do dispositivo, prototipagem, testes de temperatura, consumo de corrente, estabilidade eletromecânica e testes de desempenho associados a diferentes valores de pressão e de caudal de funcionamento, foram essenciais para este desenvolvimento, assim como, análises estruturais e morfológicas do material que constitui o núcleo dos solenóides. Além disso, procurou-se responder às necessidades do mercado numa perspetiva mais completa do que a existente. Para isso, foram produzidos dois tipos de solenóides de 24 V AC, com pressões máximas de funcionamento de 4 bar e de 12 bar.

Measured Time: Imposing a Temporal Metric toClassificatory Structures

Describes three units of time helpful for understanding and evaluating classificatory structures: long time (versions and states of classification schemes), short time (the act of indexing as repeated ritual or form), and micro-time (where stages of the interpretation process of indexing are separated out and inventoried). Concludes with a short discussion of how time and the impermanence of classification also conjures up an artistic conceptualization of indexing, and briefly uses that to question the seemingly dominant understanding of classification practice as outcome of scientific management and assembly line thought.

Lo que los trabajadores quieren vs. lo que las empresas necesitan. Implementación de las anclas de carrera de Edgar Schein en un contact centre

El compromiso laboral entre los trabajadores y las organizaciones es uno de los activos con mayor poder explicativo para consolidar un alto desempeño e incrementar la productividad. Para lograr eso es fundamental conocer cuáles son las vocaciones de los trabajadores actuales y futuros y de qué manera estas motivaciones de carrera encuentran articulación con la misión y la visión de la compañía. El problema es que las empresas fallan sistemáticamente en este proceso. El modelo de anclas de carrera (ac) de Edgar Schein es una metodología que permite conocer cuáles son las motivaciones de carrera de los individuos. Este documento tiene como propósito establecer un vínculo entre las ac y los procesos de selección, vinculación, y retención del capital humano en un contact centre que se desempeña en Bogotá, Colombia. Para alcanzar este propósito, se implementó el modelo de ac en una muestra de 116 trabajadores del área de gestión de esta compañía. El informe presenta el análisis de resultados y las propuestas sugeridas por los autores a la gerencia de la compañía.

Comparison between 5G private network and Wifi6 in industrial environment

Industry 4.0 refers to the 4th industrial revolution and at its bases, we can see the digitalization and the automation of the assembly line. The whole production process has improved and evolved thanks to the advances made in networking, and AI studies, which include of course machine learning, cloud computing, IoT, and other technologies that are finally being implemented into the industrial scenario. All these technologies have in common a need for faster, more secure, robust, and reliable communication. One of the many solutions for these demands is the use of mobile communication technologies in the industrial environment, but which technology is better suited for these demands? Of course, the answer isn’t as simple as it seems. The 4th industrial revolution has a never seen incomparable potential with respect to the previous ones, every factory, enterprise, or company have different network demands, and even in each of these infrastructures, the demands may diversify by sector, or by application. For example, in the health care industry, there may be e a need for increased bandwidth for the analysis of high-definition videos or, faster speeds in order to have analytics occur in real-time, and again another application might be higher security and reliability to protect patients’ data. As seen above, choosing the right technology for the right environment and application, considers many things, and the ones just stated are but a speck of dust with respect to the overall picture. In this thesis, we will investigate a comparison between the use of two of the available technologies in use for the industrial environment: Wi-Fi 6 and 5G Private Networks in the specific case of a steel factory.

Implementazione della metodologia lean nella realizzazione di una nuova linea di assemblaggio per bruciatori residenziali. il caso Riello.

L'elaborato proposto illustra l'implementazione della metodologia di Lean Manufacturing nella progettazione di una linea di assemblaggio destinata alla realizzazione di bruciatori residenziali. Vengono messi in evidenza i principali strumenti avanzati dal Toyota Production System e viene condotta un'analisi sull'influenza di tale approccio sulle maggiori aziende del settore Automotive degli ultimi decenni. Il caso di studio mette a confronto la linea di produzione in oggetto a monte e a valle dell'implementazione Lean presso l'azienda Riello S.p.a. di Legnago (VR). Si evidenziano i benefici apportati in termini di output produttivo giornaliero e riduzione dei costi di manodopera attraverso il miglioramento continuo del processo, l'adozione di nuovi utensili e l'applicazione del metodo Yamazumi nel ribilanciamento delle operazioni manuali.

Translation and assembly of HLA-DR antigens in Xenopus oocytes injected with mRNA from a human B-cell line.

HLA-DR antigens are polymorphic cell surface glycoproteins, expressed primarily in B lymphocytes and macrophages, which are thought to play an important role in the immune response. Two polypeptide chains, alpha and beta, are associated at the cell surface, and a third chain associates with alpha and beta intracellularly. RNA isolated from the human B-cell line Raji was injected in Xenopus laevis oocytes. Immunoprecipitates of translation products with several monoclonal antibodies revealed the presence of HLA-DR antigens similar to those synthesized in Raji cells. One monoclonal antibody was able to bind the beta chain after dissociation of the three polypeptide chains with detergent. The presence of all three chains was confirmed by two-dimensional gel electrophoresis. The glycosylation pattern of the three chains was identical to that observed in vivo, as evidenced in studies using tunicamycin, an inhibitor of N-linked glycosylation. The presence of alpha chains assembled with beta chains in equimolar ratio was further demonstrated by amino-terminal sequencing. An RNA fraction enriched for the three mRNAs, encoding alpha, beta, and intracellular chains, was isolated. This translation-assembly system and the availability of monoclonal antibodies make it possible to assay for mRNA encoding specific molecules among the multiple human Ia-like antigens.

The t(10;11)(p13;q14) in the U937 cell line results in the fusion of the AF10 gene and CALM, encoding a new member of the AP-3 clathrin assembly protein family.

The translocation t(10;11)(p13;q14) is a recurring chromosomal abnormality that has been observed in patients with acute lymphoblastic leukemia as well as acute myeloid leukemia. We have recently reported that the monocytic cell line U937 has a t(10;11)(p13;q14) translocation. Using a combination of positional cloning and candidate gene approach, we cloned the breakpoint and were able to show that AF10 is fused to a novel gene that we named CALM (Clathrin Assembly Lymphoid Myeloid leukemia gene) located at 11q14. AF10, a putative transcription factor, had recently been cloned as one of the fusion partners of MLL. CALM has a very high homology in its N-terminal third to the murine ap-3 gene which is one of the clathrin assembly proteins. The N-terminal region of ap-3 has been shown to bind to clathrin and to have a high-affinity binding site for phosphoinositols. The identification of the CALM/AF10 fusion gene in the widely used U937 cell line will contribute to our understanding of the malignant phenotype of this line.

Expression of human inducible nitric oxide synthase in a tetrahydrobiopterin (H4B)-deficient cell line: H4B promotes assembly of enzyme subunits into an active dimer.

Murine inducible nitric oxide (NO) synthase (iNOS) is catalytically active only in dimeric form. Assembly of its purified subunits into a dimer requires H4B. To understand the structure-activity relationships of human iNOS, we constitutively expressed recombinant human iNOS in NIH 3T3 cells by using a retroviral vector. These cells are deficient in de novo H4B biosynthesis and the role of H4B in the expression and assembly of active iNOS in an intact cell system could be studied. In the absence of added H4B, NO synthesis by the cells was minimal, whereas cells grown with supplemental H4B or the H4B precursor sepiapterin generated NO (74.1 and 63.3 nmol of nitrite per 10(6) cells per 24 h, respectively). NO synthesis correlated with an increase in intracellular H4B but no increase in iNOS protein. Instead, an increased percentage of dimeric iNOS was observed, rising from 20% in cytosols from unsupplemented cells to 66% in H4B-supplemented cell cytosols. In all cases, only dimeric iNOS displayed catalytic activity. Cytosols prepared from H4B-deficient cells exhibited little iNOS activity but acquired activity during a 60- to 120-min incubation with H4B, reaching final activities of 60-72 pmol of citrulline per mg of protein per min. Reconstitution of cytosolic NO synthesis activity was associated with conversion of monomers into dimeric iNOS during the incubation. Thus, human iNOS subunits dimerize to form an active enzyme, and H4B plays a critical role in promoting dimerization in intact cells. This reveals a post-translational mechanism by which intracellular H4B can regulate iNOS expression.

Report to the Illinois General Assembly on the issue of expanding public water supply loan eligibility to privately owned community water supplies /

"August 1998."