Bin picking de objetos polimórficos convexos usando perceção 3D

O bin picking é um processo de grande interesse na indústria, uma vez que permite maior automatização, aumento da capacidade de produção e redução dos custos. Este tem vindo a evoluir bastante ao longo dos anos e essa evolução fez com que sistemas de perceção 3D começassem a ser implementados. Este trabalho tem como principal objetivo desenvolver um sistema de bin picking usando apenas perceção 3D. O sistema deve ser capaz de determinar a posição e orientação de objetos com diferentes formas e tamanhos, posicionados aleatoriamente numa superfície de trabalho. Os objetos utilizados para fazer os testes experimentais, são esferas, cilindros e prismas, uma vez que abrangem as formas geométricas existentes em muitos produtos submetidos a bin picking. Após a identi cação e seleção do objeto a apanhar, o manipulador deve autonomamente posicionar-se para fazer a aproximação e recolha do mesmo. A aquisição de dados é feita através de uma câmara Kinect. Dos dados recebidos apenas são trabalhados os referentes à profundidade, centrando-se assim este trabalho na análise e tratamento de nuvem de pontos. O sistema desenvolvido cumpre com os objetivos estabelecidos. Consegue localizar e apanhar objetos em várias posições e orientações. Além disso apresenta uma velocidade de processamento compatível com a aplicação em causa.

Exploiting the bin-class histograms for feature selection on discrete data

In machine learning and pattern recognition tasks, the use of feature discretization techniques may have several advantages. The discretized features may hold enough information for the learning task at hand, while ignoring minor fluctuations that are irrelevant or harmful for that task. The discretized features have more compact representations that may yield both better accuracy and lower training time, as compared to the use of the original features. However, in many cases, mainly with medium and high-dimensional data, the large number of features usually implies that there is some redundancy among them. Thus, we may further apply feature selection (FS) techniques on the discrete data, keeping the most relevant features, while discarding the irrelevant and redundant ones. In this paper, we propose relevance and redundancy criteria for supervised feature selection techniques on discrete data. These criteria are applied to the bin-class histograms of the discrete features. The experimental results, on public benchmark data, show that the proposed criteria can achieve better accuracy than widely used relevance and redundancy criteria, such as mutual information and the Fisher ratio.

Otimização da atividade de picking num armazém de peças – um caso de estudo

Mestrado em Engenharia Mecânica – Gestão Industrial

A mathematical model for supermarket order picking

Order picking consists in retrieving products from storage locations to satisfy independent orders from multiple customers. It is generally recognized as one of the most significant activities in a warehouse (Koster et al, 2007). In fact, order picking accounts up to 50% (Frazelle, 2001) or even 80% (Van den Berg, 1999) of the total warehouse operating costs. The critical issue in today’s business environment is to simultaneously reduce the cost and increase the speed of order picking. In this paper, we address the order picking process in one of the Portuguese largest companies in the grocery business. This problem was proposed at the 92nd European Study Group with Industry (ESGI92). In this setting, each operator steers a trolley on the shop floor in order to select items for multiple customers. The objective is to improve their grocery e-commerce and bring it up to the level of the best international practices. In particular, the company wants to improve the routing tasks in order to decrease distances. For this purpose, a mathematical model for a faster open shop picking was developed. In this paper, we describe the problem, our proposed solution as well as some preliminary results and conclusions.

Otimização da operação de picking em armazéns

A Logística, vista como uma perspetiva integradora entre os parceiros de negócio, com objetivos comuns de proporcionar ao cliente mais-valias e aspetos diferenciadores perante os outros concorrentes, contribui em muito na manutenção das empresas na globalização atual, que se torna cada vez mais flexível. Através de uma boa gestão de processos críticos de negócio, boa localização dos materiais, sejam eles quais forem, produtos finais, matérias-primas ou produtos em vias de fabrico e através do transporte a logística cria utilidade temporal e diferenciadora. De facto, a logística poderá assumir um papel fundamental em proporcionar valor acrescentado ao disponibilizar, a tempo, os serviços que os clientes necessitam ou esperam. Enquadrando-se na temática de gestão dos armazéns, o presente projeto consistiu no estudo de operações de picking com a finalidade de otimização dos processos de picking no armazém do operador logístico AR – Serviços de Logística, localizado em Ribeirão, Vila Nova de Famalicão. O trabalho inicial passou pelo levantamento do funcionamento das operações do processo de picking na empresa e posteriormente confrontá-los com as tecnologias e procedimentos atuais no mercado. Com base nos resultados obtidos, foi possível definir e implementar métricas enquadradas nas finalidades estratégicas e operacionais do operador logístico. As soluções passaram também pela melhoria da aplicação de gestão de armazéns (WMS), reavaliação dos indicadores previamente estabelecidos e na aquisição de equipamentos para automatização das operações picking e localizações. Os registos e informações relacionadas com os módulos fulcrais são armazenados e tratados na base de dados de suporte à aplicação com contributo de melhoria contínua aos procedimentos logístico da empresa e sua relação com os stakeholders na estratégia global de negócio com o operador logístico. Finalmente, foi possível analisar os resultados obtidos em modo real em relação as estimativas calculadas e definidas na fase de implementação e desenvolvimento.

Análise e melhoria do processo de order-picking num sistema produtivo: caso de estudo

Dissertação para obtenção do Grau de Mestre em Engenharia e Gestão Industrial

A skin-picking disorder case report: a psychopathological explanation

We describe the case of a 44-year-old woman, without known previous psychiatric history, hospitalized after a significant hemorrhage caused by self-inflicted deep facial dermal lesions (with muscle exposition). Psychopathological possible explanations of this case, as in similar reviewed ones, are related to frustration, aggression, and impulsivity.

Picking the Right Budget Constraint for Scotland

This position paper considers the devolution of further fiscal powers to the Scottish Parliament in the context of the objectives and remit of the Smith Commission. The argument builds on our discussion of fiscal decentralization made in our previous published work on this topic. We ask what sort of budget constraint the Scottish Parliament should operate with. A soft budget constraint (SBC) allows the Scottish Parliament to spend without having to consider all of the tax and, therefore, political consequences, of that spending, which is effectively the position at the moment. The incentives to promote economic growth through fiscal policy – on both the tax and spending sides are weak to non-existent. This is what the Scotland Act, 1998, and the continuing use of the Barnett block grant, gave Scotland. Now other budget constraints are being discussed – those of the Calman Commission (2009) and the Scotland Act (2012), as well as the ones offered in 2014 by the various political parties – Scottish Conservatives, Scottish Greens, Scottish Labour, the Scottish Liberal Democrats and the Scottish Government. There is also the budget constraint designed by the Holtham Commission (2010) for Wales that could just as well be used in Scotland. We examine to what extent these offer the hard budget constraint (HBC) that would bring tax policy firmly into the realm of Scottish politics, asking the Scottish electorate and Parliament to consider the costs to them of increasing spending in terms of higher taxes; or the benefits to them of using public spending to grow the tax base and own-sourced taxes? The hardest budget constraint of all is offered by independence but, as is now known, a clear majority of those who voted in the referendum did not vote for this form of budget constraint. Rather they voted for a significant further devolution of fiscal powers while remaining within a political and monetary union with the rest of the UK, with the risk pooling and revenue sharing that this implies. It is not surprising therefore that none of the budget constraints on offer, apart from the SNP’s, come close to the HBC of independence. However, the almost 25% fall in the price of oil since the referendum, a resource stream so central to the SNP’s economic policy making, underscores why there is a need for a trade off between a HBC and risk pooling and revenue sharing. Ranked according to the desirable characteristic of offering something approaching a HBC the least desirable are those of the Calman Commission, the Scotland Act, 2012, and Scottish Labour. In all of these the ‘elasticity’ of the block grant in the face of failure to grow the Scottish tax base is either not defined or is very elastic – meaning that the risk of failure is shuffled off to taxpayers outside of Scotland. The degree of HBC in the Scottish Conservative, Scottish Greens and Scottish Liberal Democrats proposals are much more desirable from an economic growth point of view, the latter even embracing the HBC proposed by the Holtham Commission that combines serious tax policy with welfare support in the long-run. We judge that the budget constraint in the SNP’s proposals is too hard as it does not allow for continuation of the ‘welfare union’ in the UK. We also consider that in the case of a generalized UK economic slow requiring a fiscal stimulus that the Scottish Parliament be allowed increased borrowing to be repaid in the next economic upturn.

Comparing population distributions from bin-aggregated sample data: an application to historical height data from France

This paper develops a methodology to estimate the entire population distributions from bin-aggregated sample data. We do this through the estimation of the parameters of mixtures of distributions that allow for maximal parametric flexibility. The statistical approach we develop enables comparisons of the full distributions of height data from potential army conscripts across France's 88 departments for most of the nineteenth century. These comparisons are made by testing for differences-of-means stochastic dominance. Corrections for possible measurement errors are also devised by taking advantage of the richness of the data sets. Our methodology is of interest to researchers working on historical as well as contemporary bin-aggregated or histogram-type data, something that is still widely done since much of the information that is publicly available is in that form, often due to restrictions due to political sensitivity and/or confidentiality concerns.

Implementació d'un algorisme d'optimització de rutes de Picking i reposició de magatzems

Implementar un algorisme per a l'optimització de rutes de Picking i de reposició de magatzems. Estudi i anàlisi de dos magatzems on es realitzaran proves mitjançant l'algorisme per saber quin és el millor.