Application of artificial intelligence techniques to the smart control of sheet metal forming processes

The present research work aims at evaluating the economical feasibility and the technological viability of implementing intelligent control systems in complex industrial manufacturing processes; in this case forming processes. Forming processes are manufacturing processes that use force and pressure in order to modify the shape of a material part until getting the final product. The wide range of non-linear factors (material properties, tool geometry, machine parameters and lubrication variables) that determine the final quality of the parts manufactured by these processes makes them to be inherently quite unstable. Thus, the control made by human operators is still essential nowadays. On the other hand, although human operators have demonstrated to be a very successful strategy when controlling this type of processes, the actual market evolution towards the fabrication of more complex parts, made of lower formability materials at higher production rates is decreasing their capacity of reaction when solving the daily problems. Therefore, the development of new automatic and global control systems based, not on traditional control techniques and mathematical models but on the control strategy that has been successfully used for many years, the control through the experience and knowledge, is now even more necessary. In the present research work, two intelligent control systems based on AI techniques have been developed and evaluated. The main purpose of these intelligent control systems is to identify the process failures at forming processes and to propose the right solutions that should lead to their solution, all this in a quick and reliable way. Following this strategy, the solution of the process failures is considerably simplified because, after any process failure of defective part detection, human operators find a report where an explanation of the incidence, as well as its causes and the way to solve it, are displayed. This has the inherent advantage of decreasing the length of the downtimes at the manufacturing facilities and thus increasing the number of parts produced. Together with the previously described core of the global control systems, two monitoring systems have been developed and implemented in a forming facility too. The purpose of these monitoring systems is to work as the senses of the intelligent control systems. The first one, an artificial vision system, is aimed at evaluating the quality of the produced parts by carrying out a 100% quality control at the end of the forming process. This will assure the right quality of all the products shipped to the customer. The second one, a sensors based process monitoring system, is aimed at detecting any process failure at the forming facility by means of force and acoustic emissions measurements. This will reduce the internal defective and will assure the security of the forming facility. Both systems are in charge of detecting any process failure and defective part and of reporting about them to the intelligent control system. Since the aim of the research work was to evaluate the feasibility of implementing global intelligent control systems in the industry, all the developments and results achieved through the present research work have been carried out in an industrial environment. The research work is principally divided into three main parts; 1) the development and implementation of the sensors based process monitoring system, 2) the development and implementation of the AV monitoring system and 3) the development of the intelligent control systems. At the end, a summary of all the results and conclusions achieved through the development of the previous mentioned systems is given too.Ikerkuntza lan honen helburua sistema adimendunak fabrikazio prozesu konplexuak kontrolatzeko erabiltzearen bideragarritasuna aztertzea da, bai ekonomikoki eta teknologikoki. Kasu honetan, konformazio prozesuetan inplementatutako sistema adimenduak ikertu dira. Konformazio prozesuak, amaierako produktua lortzeko, hasierako materialari esfortzu edo presioen bidez forma geometrikoa aldatzean datzate. Konformaturiko piezen amaierako kalitatea finkatzen duten aldagai ez-linealen ugaritasun zabalak (materialen propietateak, lanabesen geometriak, makinen parametroak eta/edo lubrifikazioa) prozesu hauek ezegonkorrak izatea ondorioztatzen du. Hori dela medio, gaur egun ere, prozesu hauen kontrola giza-langile bidez egiten da. Langileak prozesu hauek modu eraginkorrean kontrolatzeko gai direla erakutsi du esperientziak. Dena den, deformagarritasun txikiagoko materialez eginiko pieza konplexuagoak kadentzia altuagoetan fabrikatzeko gaur egungo joerak, langileek ezustekoen aurrean erantzuteko duten gaitasuna gutxitu du. Ondorioz, prozesua gainbegiratu eta kontrolatzen duten sistema automatiko eta adimendu berrien garapena beharrezkoa bihurtu da. Sistema hauek ez daude kontrol teknika tradizional edo eredu matematikoetan oinarrituak. Sistema hauen kontrola ezagutza eta esperientzian oinarriturik dago, zeinak azken urteetan emaitza onak eman dituen. Ikerkuntza lan honetan adimen artifizial tekniketan oinarrituriko bi kontrol sistema adimendun garatu eta baloratu dira. Sistema hauen helburu nagusia konformazio prozesuetan emaniko akatsak identifikatu eta automatikoki ebazpenproposamenak aurkeztea da, modu azkar eta sendoan. Estrategia hau jarraituz, prozesuko akatsen ebazpena errazten da, pieza akastunak atzematean edo makinaren geldialdi baten aurrean, sistemak langilea eman beharreko pausuak azaltzen dizkion txosten batez hornituko baitu. Makinaren geldialdiaren murriztea eta ondorioz, produktibitatea igotzea da honen abantaila nagusia, akatsen identifikazioa berehalakoa baita. Kontrol sistema garatzeaz gain, puntzonaketa instalakuntza batean bi monitorizazio sistema martxan jarri dira. Bi monitorizazio sistema hauen helburua prozesuaren informazioa jaso eta kontrol sistemari bidaltzea da. Lehenengoa ikuspen artifizialeko sistema bat da, zeinaren helburua ekoiztutako piezen %100aren kalitatea aztertzea den. Honenbestez, bezeroei bidalitako piezen kalitate egokia bermatzen da. Bigarrena sentsoreetan oinarrituriko prozesuen monitorizazio sistema bat da. Bere helburua prozesuan emaniko edozein akats antzematea da. Honek akastun piezen kantitatea gutxitzen du eta instalakuntzak prozesuen ezegonkortasunetatik babesten ditu. Ondorioz, bi sistemen helburua prozesuan izandako arazo edo pieza akastunak antzematea eta kontrol sistemari hauen berri ematea da. Lan honen helburua aurrez aipaturiko sistemen gaitasuna industri ingurunean ebaluatzea denez, aurkezturiko garapen eta emaitzak enpresa batean burutu dira. Hiru atal nagusi bereiz daitezke lan honetan: 1) sentsoreetan oinarrituriko monitorizazio sistema baten garapen eta inplementazioa; 2) ikuskapen artifizialeko sistemaren garapen eta inplementazioa; eta 3) adimendun kontrolean oinarrituriko sistemen garapena.El presente trabajo de investigación tiene como objetivo evaluar en qué condiciones es económicamente viable y tecnológicamente factible la implementación de sistemas inteligentes de control en procesos de fabricación complejos; en este caso procesos de conformado. Los procesos de conformado son procesos de fabricación basados en la aplicación de esfuerzos o presiones sobre componentes con el objetivo de modificar su forma geométrica hasta conseguir un producto final. El gran abanico de variables no lineales (propiedades de materiales, geometría de herramientas, parámetros de máquinas y/o lubricación) que determinan la calidad final de las piezas conformadas hacen que estos procesos sean inherentemente inestables. Por ello, aun hoy en día, el control de estos procesos se realiza mediante operarios humanos. Por otro lado, aunque la experiencia ha demostrado que los operarios son capaces de controlar estos procesos de manera eficiente, la actual tendencia hacia la fabricación de piezas más complejas, fabricadas en materiales menos deformables y todo ello a cadencias de fabricación mayores, ha hecho que la capacidad de los operarios para reaccionar ante imprevistos se haya visto mermada. Por lo tanto, el desarrollo de nuevos sistemas automáticos e inteligentes de supervisión y control basados, no en técnicas tradicionales de control o en modelos matemáticos, sino en la estrategia de control que ha dado buenos resultados a lo largo de los años, el control basado en la experiencia y el conocimiento, es cada vez más necesario. En el presente trabajo de investigación, se han desarrollado y evaluado dos sistemas inteligentes de control basados en técnicas de inteligencia artificial. El principal objetivo de estos sistemas es ser capaces de identificar los fallos de proceso en procesos de conformado así como de plantear, automáticamente, las instrucciones para su resolución, todo ello de una manera rápida y robusta. Siguiendo esta estrategia, la resolución de los fallos de proceso se simplifica ya que, tras una parada de máquina o la detección de piezas defectuosas, el sistema proporciona al operario un informe donde se detallan las acciones a llevar a cabo. Esto tiene como ventaja una reducción en los tiempos de parada de máquina (y por lo tanto aumento en la cantidad de piezas producidas) ya que la identificación de los fallos es inmediata. Junto con el núcleo del sistema global de control, se han desarrollado e implementando en una instalación de corte progresivo dos sistemas de monitorización. El objetivo de estos dos sistemas de monitorización es recoger información sobre el proceso y enviársela al sistema de control. El primero, un sistema de visión artificial, tiene como objetivo analizar la calidad del 100% de las piezas fabricadas. Esto asegura la correcta calidad de todas las piezas enviadas a los clientes. El segundo, un sistema de monitorización de procesos basado en sensores, tiene como objetivo la detección de cualquier fallo de proceso. Esto reduce el defectivo interno y protege a las instalaciones frente a anomalías de proceso. Por lo tanto, ambos sistemas tienen como misión la detección de cualquier anomalía de proceso o pieza defectiva así como informar al sistema de control sobre las mismas. Puesto que el objetivo de este trabajo es evaluar la capacidad de los sistemas anteriormente citados en el entorno industrial, todos los desarrollos y resultados obtenidos a lo largo del mismo se han llevado a cabo en una empresa. El trabajo se puede dividir en tres partes: 1) el desarrollo e implementación del sistema de monitorización basado en sensores, 2) el desarrollo e implementación del sistema de visión artificial y 3) el desarrollo de los sistemas de control inteligentes

The Effect of Architectural Variation in Habitat on a Spider Community: An Experimental Field Study -- with Special Reference to Resource Partitioning

Spider community acceptance of, and segregation by, architectural configuration was investigated for the spiders of Green Canyon in northern Utah. Modular habitat units consisting of 30.48 centimeter (1 foot) cubes of chicken wire supporting internal strands of macrame jute tied in different orthogonal configurations were used. Configurations including all three axes were tested at two strand densities. The primary null hypothesis tested, that spider species use structures independent of architecture, was rejected in favor of the alternate hypothesis that spider species differentially use structures dependent upon architecture. Of the eight most abundant species, two showed preferences for horizontal substrata and one chose vertical substrata. All spiders strongly responded to the amount of jute available in each module. The two most abundant jumping spiders were biased toward modules with widely spaced jute, while the two most abundant web-builders preferred closely spaced jute. Of the eight most abundant species, two species fell within each of the following four hunting guilds: jumpers, ambushers, pursuers, and web-builders. Within each pair of species, juveniles of the larger species emerged earlier in each of the two field seasons studied. In three of the species pairs, the body lengths were sufficiently different to fulfill theoretical requirements for their coexistence based upon differential prey size use. The remaining species pair, ambushers, had sufficiently different cryptic coloration and abundance patterns to suggest that their coexistence was determined by a combination of microhabitat and seasonal separation

Forecasting stock price movements using neural networks

Includes bibliographical references (p. 99-101).The prediction of security prices has shown to be one of the most important but most difficult tasks in financial operations. Linear approaches failed to model the non-linear behaviour of markets and non-linear approaches turned out to posses too many constraints. Neural networks seem to be a suitable method to overcome these problems since they provide algorithms which process large sets of data from a non-linear context and yield thorough results. The first problem addressed by this research paper is the applicability of neural networks with respect to markets as a tool for pattern recognition. It will be shown that markets posses the necessary requirements for the use of neural networks, i.e. markets show patterns which are exploitable

A study of the reaction of hydrated lime with pure clay (kaolin) in clay stabilization

The work presented is the investigation of the reaction of pure Kaolinite clay with hydrated lime in clay stabilization. Pure Kaolin clay, ranging from one micron to five microns in size, was mixed with calcium hydroxide in the form of a paste. These mixtures were permitted to react for varying periods of time. An attempt was made to separate the lime from clay lime mixture by density separation using a mixed solution of carbon tetrachloride and tetrabromoethane. Since the above method failed because of the formation of a yellow gelatinous suspension, the lime was removed by washing the clay lime mixture in a concentrated solution of ammonium chloride and finally in water. Electron photographs of clay before and after the treatment were compared for changes in edge sharpness or corner erosion. No notable changes ware observed by comparison of the photographs. The clay lime mixtures were also tested in the Geiger counter X-ray spectrometer. These tests gave no indication of formation of new products of reaction between the clay and lime additives. It is concluded that the reaction is a surface phenomenon only --Abstract, page 2

La cultura dei servizi di accoglienza migranti in Italia. Una ricerca esplorativa [The culture of migrant reception services in Italy. An exploratory research]

Italy has a long history of immigration, which has become part of the country’s landscape in a complex and varied way, and has led to significant changes in important contexts such as in the school, the work place, and in the provision of welfare services. And yet, immigration policies still consist in emergency measures that do not recognize the phenomenon in its long -standing and structural dimension. In addition, public opinion is concerned as a result of the alarmist distortion of this issue, as shown by the gapbetween data on immigration and perceived immigration. Since in this research we take into consideration collusively shared experiences, these misunderstandings can not be corrected by providing more information on the real data; we posit that the emotional scope must be recognized in order to address this issue. In particular, we asked ourselves how this context -changes brought by immigration, public opinion, and government policies -is repre sented within the migrant Accordingly, we interviewed a group of reception staff from the Roman area on the type of service that they think they are offering. The results show how, in their experience, this complex reality of immigration is not evoked: the experience within the services is isolated from the Italian narrative and context. However, the voice of migrants and their point of view, emerge as a resource within these services, as openness rather than isolation

Identification and predictability of soil quality indicators from conventional soil and vegetation classifications

The physical, chemical and biological attributes of a soil combined with abiotic factors (e.g. climate and topography) drive pedogenesis and some of these attributes have been used as proxies to soil quality. Thus, we investigated: (1) whether appropriate soil quality indicators (SQIs) could be identified in soils of Great Britain, (2) whether conventional soil classification or aggregate vegetation classes (AVCs) could predict SQIs and (3) to what extent do soil types and/ or AVCs act as major regulators of SQIs. Factor analysis was used to group 20 soil attributes into six SQI which were named as; soil organic matter (SOM), dissolved organic matter (DOM), soluble N, reduced N, microbial biomass, DOM humification (DOMH). SOM was identified as the most important SQI in the discrimination of both soil types and AVCs. Soil attributes constituting highly to the SOM factor were, microbial quotient and bulk density. The SOM indicator discriminated three soil type groupings and four aggregate vegetation class groupings. Among the soil types, only the peat soils were discriminated from other groups while among the AVCs only the heath and bog classes were isolated from others. However, the peat soil and heath and bog AVC were the only groups that were distinctly discriminated from other groups. All other groups heavily overlapped with one another, making it practically impossible to define reference values for each soil type or AVC. The two-way ANOVA showed that the AVCs were a better regulator of the SQIs than the soil types. We conclude that conventionally classified soil types cannot predict the SQIs defined from large areas with differing climatic and edaphic factors. Localised areas with similar climatic and topoedaphic factors may hold promise for the definition of SQI that may predict the soil types or AVCs

Comparison of the epifaunal assemblage of an invasive and native macroalga

The rapid spread of introduced seaweeds is of essential concern, as they can have a deleterious impact on coastal native seaweed and seagrass communities. However, non-indigenous species can generate mixed responses when introduced to native assemblages, and increase habitat complexity, depending on the spatial and ecological context. By taking advantage of the cooccurrence of the native Ulva seaweeds and the non-native Agarophyton vermiculophyllum in the Clonakilty estuary (Cork, Ireland) we aim to assess the differences of the epifaunal community of the native and invasive macroalgal species and how epifaunal biodiversity may be affected by the invasive. In four locations over four sampling occasions, a total of 253 quadrants of algae and epifaunal biomass were sampled. The Ulva dominated sections mainly contained macroalgae with tubular morphotypes and some sporadic patches of laminar Ulva rigida. The average algal biomass of both species was similar, however, the biomass of the red seaweed was highly variable throughout the seasons. The native algal canopy hosted up to four times more epifaunal biomass compared to the invasive rhodophyte. Moreover, the epifaunal community of both canopies differed substantially, whereas deposit-feeding organisms had a higher abundance in Ulva spp. canopies and the carnivorous crab, Carcinus maenas, was much more abundant in A. vermiculophyllum samples. The native green macroalgae hosted more invertebrate taxa, however no difference in biodiversity was found. Increased predation on deposit-feeders and grazers, as well as, the structural and chemical resistance of A. vermiculophyllum against grazing and overgrowth by epiphytes may reduce the trophic transfer from primary production toward higher trophic levels.As introduções de espécies exóticas ocorrem já há vários séculos, de forma intencional para ganho comercial ou involuntariamente, maioritariamente por transporte marítimo como passageiros escondidos em águas de lastro ou agarrados ao casco do navio. A rápida dispersão de algas não-indígenas é uma preocupação básica, já que podem ter impactos nocivos nas comunidades algas e ervas marinhas costeiras indígenas e são, juntamente com as alterações climáticas, um dos fatores de stress mais significativos dos ecossistemas de hoje. Estes impactos incluem a modificação da estrutura da comunidade da fauna, redução de biodiversidade e alteração das dinâmicas de nutrientes estuarinas, que podem, em última instância, acelerar a mudança de macrófitas de crescimento lento para macroalgas efémeras, aumentando o risco de afloramentos de macroalgas. No entanto, as espécies não-indígenas podem gerar respostas mistas quando introduzidas em agrupamentos nativos, e aumentar a complexidade do habitat, dependendo do contexto espacial e ecológico. Os factores de stress antropogénicos como o aumento dos níveis de nutrientes podem intensificar a magnitude de tais eventos e aumentar a sua frequência. A referida eutrofização aparente de sistemas costeiros pode fomentar as invasões de macrófitas, assim como a sua resistência a grazing o que aumenta ainda mais a probabilidade de afloramentos de macroalgas. Duas espécies indígenas de forma laminar (Ulva rigida e Ulva gigantea) e duas espécies indígenas de forma tubular (Ulva prolifera e Ulva compressa) do género Ulva bem como a rodófita não-indígena A.vermiculophyllum foram identificadas no estuário de Clonakilty (Condado de Cork, Irlanda) e estão a formar canópias distintas próximas umas das outras. A identificação de efeitos positivos ou negativos de uma espécie não-indígena em ecossistemas estuarinos e a forma como é controlada teria implicações notáveis nas estratégias de gestão de espécies invasivas fundacionais. Os vários impactos ecológicos na diversidade da epifauna e a utilização de nutrientes precisam de ser avaliados, especialmente no contexto do sobre-enriquecimento de nutrientes antropogénico local e a mudança global para reconhecer e recomendar uma estratégia apropriada (activa ou passiva). Ao tirar proveito da co-ocorrência de algas indígenas e não-indígenas neste estuário, tivemos como objectivos: (i) a comparação de padrões espaciais e temporais na estrutura de comunidades de epifauna em ambas as algas; (ii) caracterizar o seu papel na formação de habitats de ambas as espécies e as suas implicações em diferentes taxa da fauna; (iii) explorar implicações ecológicas para diferentes guildas alimentares e discutir o impacto em cascadas tróficas; e (iv) a avaliação da biodiversidade da epifauna e a riqueza das espécies de macroalgas.(…