Mathematical Modeling of Manufacturing Lines with Distribution by Process: A Markov Chain Approach

Today, there are a wide variety of ways to produce goods in a manufacturing company. Among the most common are mass or line production and process production, both of which are antagonists. In an online production system, materials move from station to station, receiving added value on a well-defined layout. In a production line by process, the materials randomly visit a set of machines strategically located in order to receive a treatment, almost always through metalwork machines, according to the final product of which they will be part. In this case, there is not a predefined layout, as the incoming materials are sectioned and each piece forms a continuous flow through different workstations to receive some process. This activity depends on the function of the product and its final destination as a component of a finished product. In this proposal, Markov chain theory is used to model a manufacturing system by process in order to obtain the expected values of the average production per machine, the total expected production in all the facilities, the leisure per machine and the total productive efficiency of the system, among other indicators. In this research, we assume the existence of historical information about the use of the equipment, its failures, the causes of failure and their repair times; in any factory, this information is available in the area of manufacturing engineering and plant engineering. From this information, statistical frequency indicators are constructed to estimate transition probabilities, from which the results presented here are derived. The proposal is complemented with a numerical example of a real case obtained from a refrigerator factory established in Mexico in order to illustrate the results derived from this research. The results obtained show their feasibility when successfully implemented in the company.

TAKT TIME E BALANCEAMENTO NO FORMATO DA PROGRAMAÇÃO DE LINHA DE PRODUÇÃO

Produzir mais, empregando menos tempo e menos recursos, é o sonho de qualquer empresa. Diante disso, este estudo busca resolver problemas de utilização da capacidade e de desnivelamentos de produção. Dessa maneira, o objetivo consiste em propor um formato de programação que otimize a utilização dos recursos e resulte em maior equilíbrio na produção de uma empresa do ramo metalúrgico, produtora de implementos rodoviários e localizada na região Sul do Brasil. Por meio de um estudo de caso, identificaram-se a forma de trabalho e a situação da programação da empresa. A partir disso, criou-se um modelo de um novo formato de produção, voltado à minimização das variações de volumes e fundamentado, basicamente, na utilização dos conceitos de takt time e de balanceamento das linhas. Conclui-se que o modelo proposto permitirá um ritmo continuado na produção, sendo capaz de estabilizá-la. Ademais, conforme for aplicado nas linhas da empresa, evidenciará os pontos ao longo do fluxo que precisam de melhoria, identificando gargalos e ociosidades. A soma de tais fatores proporcionará o aprimoramento contínuo dos processos da empresa e a otimização dos recursos disponíveis para a produção. Palavras-Chave: Linha de produção. Programação de produção. Takt time. Balanceamento de linha. Capacidade produtiva. Abstract: Producing more, using less time and fewer resources, is the dream of any company. Therefore, this study seeks to solve problems of capacity utilization and production unevenness. Thus, the objective is to propose a programming format that optimizes the use of resources and results in greater balance in the production of a company in the metallurgical sector, producer of road implements and located in the southern region of Brazil. Through a case study, the way of working and the situation of the company's programming were identified. From this, a model of a new production format was created, aimed at minimizing volume variations and basically based on the use of the concepts of takt time and line balancing. It is concluded that the proposed model will allow a continued pace in production, being able to stabilize it. Furthermore, as applied to the company's lines, it will highlight the points along the flow that need improvement, identifying bottlenecks and idleness. The sum of these factors will provide the continuous improvement of the company's processes and the optimization of the resources available for production. Keywords: Production line. Production schedule. Takt time. Line balancing. Productive capacity.

Philosophy of Technoscience: From Cis-Continental to Trans-Continental

The previous chapters explored how four (interacting and overlapping) continental approaches (dialectics, dialectical materialism, psychoanalysis and phenomenology) offer hints and guidance for coming to terms with the revolutionary dynamics and disruptive impact of contemporary technoscience. Hegelian dialectics provides a conceptual scaffold for developing a comprehensive view of the terrestrial system and even for addressing the Cambrian explosion currently unfolding in laboratories around the globe, as a result of technoscientific developments such as synthetic biology and CRISP-Cas9. Dialectical materialism likewise offers a conceptual framework for addressing the rapidly aggravating disruption of the metabolism between nature and global civilisation, and the ongoing convergence of biosphere and technosphere, exemplified by the synthetic cell. Francophone psychoanalysis, closely aligned with dialectical thinking, adds to our understanding of the specificity of technoscience, both as a practice and as a discourse, where technoscientific research emerges as a questionable vocation driven by a desire to control, but at the same time ostensibly out of control. The dialectical methodology of psychoanalysis was exemplified with the help of case histories, moreover, involving Majorana particles, gene drives, malaria mosquitoes and nude mice. The latter represent technoscientific commodities, exemplifying the assembly-line production of human-made organisms (the commodification of life as such). Subsequently, we demonstrated how Heideggerian phenomenology entails important methodological hints for understanding technoscientific artefacts against the backdrop of technoscience as a mobilising force and as a global enterprise. And finally, we outlined how Teilhard’s views on the genesis of consciousness, self-consciousness and hyperconsciousness retrieve the historical (dialectical) dimension of phenomenology, thus allowing us to assess the present as a global unfolding of the noosphere.

Analysis of make-to-stock queues with general processing times and start-up and lost sales costs

We consider a make-to-stock environment with a single production unit that corresponds to a single machine or a line. Production and hence inventory are controlled by the two-critical-number policy. Production times are independent and identically distributed general random variables and demands are generated according to a stationary Poisson process. We model this production-inventory system as an M/G/1 make-to-stock queue. The main contribution of the study is to extend the control of make-to-stock literature by considering general production times, lost sales and fixed production costs at the same time. We characterize the long-run behaviour of the system and also propose a simple but very effective approximation to calculate the control parameters of the two-critical-number policy. An extensive numerical study exhibits the effects of the production time distribution and the system parameters on the policy control levels and average system cost.

The production of 4,182 mouse lines identifies experimental and biological variables impacting Cas9-mediated mutant mouse line production

The International Mouse Phenotyping Consortium (IMPC) is generating and phenotyping null mutations for every protein-coding gene in the mouse1,2. The IMPC now uses Cas9, a programmable RNA-guided nuclease that has revolutionized mouse genome editing3 and increased capacity and flexibility to efficiently generate null alleles in the C57BL/6N strain. In addition to being a valuable novel and accessible research resource, the production of >3,300 knockout mouse lines using comparable protocols provides a rich dataset to analyze experimental and biological variables affecting in vivo null allele engineering with Cas9. Mouse line production has two critical steps – generation of founders with the desired allele and germline transmission (GLT) of that allele from founders to offspring. Our analysis identified that whether a gene is essential for viability was the primary factor influencing successful production of null alleles. Collectively, our findings provide best practice recommendations for generating null alleles in mice using Cas9; these recommendations may be applicable to other allele types and species.

Development of an Efficient Cement Production Monitoring System Based on the Improved Random Forest Algorithm

Strengthening production plants and process control functions contribute to a global improvement of manufacturing systems because of their cross-functional characteristics in the industry. Companies established various innovative and operational strategies and there is increasing competitiveness among them and increase companies’ value. Machine Learning (ML) techniques have become an intelligent enticing option to address industrial issues in the current manufacturing sector since the emergence of Industry 4.0, and the extensive integration of paradigms such as big data, cloud computing, high computational power, and enormous storage capacity. Implementing a system that can identify faults early to avoid critical situations in the line production and environment is crucial. Therefore, one of the powerful machine learning algorithms is Random Forest (RF). The ensemble learning algorithm is performed to fault diagnosis and SCADA real-time data classification and predicting the state of the line production. Random Forests proved to be a better classifier with a 95% accuracy. Comparing to the SVM model, the accuracy is 94.18%, however, the K-NN model accuracy is about 93.83%, an accuracy of 80.25% is achieved using the logistic regression model, finally, about 83.73% is obtained by the decision tree model. The excellent experimental results achieved on the Random Forest model showed the merits of this implementation in the production performance, ensuring predictive maintenance, and avoid wasting energy.

Group Technology for Optimizing Manufacturing Facility Layout

In recent years, the process of cellular manufacturing and group technology have received a lot of attention and popularity in many developed countries. By applying Group Technology (GT), many benefits of flow-line production can be attained in a batch production system. GT improves material handling significantly by reducing material flow time, distance, and setup times. In this paper, an earnest investigative attempt was made to provide valuable information regarding the use of Group Technology by applying to a real world jobshop system. The proposed GT model has the flexibility of choosing the number of cells required, which is very useful in examining different manufacturing cell configurations; or in case the workshop or factory prefers a certain number of work cells. The GT model results were found satisfactory and superior to other techniques in some cases.

Whole genome analysis for 163 guide RNAs in Cas9 edited mice reveals minimal off-target activity

The Knockout Mouse Phenotyping Program (KOMP2) uses CRISRPR/Cas9 for high-throughput mouse line production to generate null alleles in the inbred C57BL/6N strain for broad-based in vivo phenotyping. In order to assess the risk of spurious S. pyogenes Cas9-induced off-target mutagenesis, we applied whole genome sequencing to compare the genomes of 50 Cas9-derived founder mice representing 163 different gRNAs to 28 untreated inbred control mice. Our analysis pipeline detected 28 off-target sequence variants associated with 21 guides. These potential off-targets were identified in 18/50 (36%) founders with 9/28 (32%) independently validated corresponding to 8 founder animals. In total, only 4.9% (8/163) of all guides exhibited off-target activity resulting in a rate of 0.16 Cas9 off-target mutations per founder analyzed. In comparison, we observed ~1225 unique variants in each mouse regardless of whether or not it was exposed to Cas9. These findings indicate that Cas9-mediated off-target mutagenesis is rare in founder knockout mice generated using guide RNAs designed to minimize off-target risk. Overall, bona fide off-target variants comprise a small fraction of the genetic heterogeneity found in carefully maintained colonies of inbred strains.