917 resultados para model-based clustering
Resumo:
Sähkönsiirtoyritysten kunnossapidon taloudellinen malli eli SKUTMA, on sähköverkkoyhtiöille suunniteltu luotettavuuspohjainen kunnossapitomalli, mikä priorisoi ja ajoittaa sähkönjakeluverkon komponenttien huolto- ja investointiajankohdat. Malli hyödyntää dynaamisen optimoinnin algoritmia kustannusminimien löytämiseksi tarkastelujaksolta ja simuloi komponenttien rappeutumasta rappeutumismallin avulla. Tässä diplomityössä on kehitetty kunnossapito-ohjelma SKUTMA-mallin pohjalta, minkä avulla tutkitaan mallin toimivuutta oikeilla johtolähdöillä ja sen hyödyntämistä sähköverkkojen kunnossapidon suunnittelussa. Työssä käydään läpi myös kunnossapitoohjelman laskenta metodiikkaa ja sen ominaisuuksia. Tämän työn lopputuloksena saadaan selkeä kuva mallin toiminnasta, käytettävyydestä ja jatkokehityspotentiaalista.
Resumo:
High levels of substrate-based 1,5-stereoinduction are obtained in the boron-mediated aldol reactions of beta-oxygenated methyl ketones with achiral and chiral aldehydes. Remote induction from the boron enolates gives the 1,5-anti adducts, with the enolate pi-facial selectivity critically dependent upon the nature of the beta-alkoxy protecting group. This 1,5-anti aldol methodology has been strategically employed in the total synthesis of several natural products. At present, the origin of the high level of 1,5-anti induction obtained with the boron enolates is unclear, although a model based on a hydrogen bonding between the alkoxy oxygen and the formyl hydrogen has been recently proposed.
Resumo:
Testaustapausten valitseminen on testauksessa tärkeää, koska kaikkia testaustapauksia ei voida testata aika- ja raharajoitteiden takia. Testaustapausten valintaan on paljon eri menetelmiä joista eniten esillä olevat ovat malleihin perustuva valinta, kombinaatiovalinta ja riskeihin perustuva valinta. Kaikkiin edellä mainittuihin menetelmiin testaustapaukset luodaan ohjelman spesifikaation perusteella. Malleihin perustuvassa menetelmässä käytetään hyväksi ohjelman toiminnasta olevia malleja, joista valitaan tärkeimmät testattavaksi. Kombinaatiotestauksessa testitapaukset on muodostettu ominaisuuspareina jolloin yhden parin testaamisesta päätellään kahden ominaisuuden toiminta. Kombinaatiotestaus on tehokas löytämään virheitä, jotka johtuvat yhdestä tai kahdesta tekijästä. Riskeihin perustuva testaus pyrkii arvioimaan ohjelman riskejä ja valitsemaan testitapaukset niiden perusteella. Kaikissa menetelmissä priorisointi on tärkeässä roolissa, jotta testauksesta saadaan riittävä luotettavuus ilman kustannusten nousua.
Resumo:
Raw measurement data does not always immediately convey useful information, but applying mathematical statistical analysis tools into measurement data can improve the situation. Data analysis can offer benefits like acquiring meaningful insight from the dataset, basing critical decisions on the findings, and ruling out human bias through proper statistical treatment. In this thesis we analyze data from an industrial mineral processing plant with the aim of studying the possibility of forecasting the quality of the final product, given by one variable, with a model based on the other variables. For the study mathematical tools like Qlucore Omics Explorer (QOE) and Sparse Bayesian regression (SB) are used. Later on, linear regression is used to build a model based on a subset of variables that seem to have most significant weights in the SB model. The results obtained from QOE show that the variable representing the desired final product does not correlate with other variables. For SB and linear regression, the results show that both SB and linear regression models built on 1-day averaged data seriously underestimate the variance of true data, whereas the two models built on 1-month averaged data are reliable and able to explain a larger proportion of variability in the available data, making them suitable for prediction purposes. However, it is concluded that no single model can fit well the whole available dataset and therefore, it is proposed for future work to make piecewise non linear regression models if the same available dataset is used, or the plant to provide another dataset that should be collected in a more systematic fashion than the present data for further analysis.
Modelagem termodinâmica por extração por solvente de metais divalentes em meio sulfato usando D2EHPA
Resumo:
The extraction of divalent metals (Mn2+, Ni2+, Co2+ and Cu2+) in the system MSO4 - H2SO4 - H2O - D2EHPA in isoparaffin (17/21) was studied by a thermodynamic model based on chemical equilibria with mass and charge balance equations. The activity coefficients of all solutes in the aqueous phase were calculated by Davies equation. By applying this model, the equilibrium concentrations of solutes were calculated from de concentration of divalent metals and pH. The predicted distribution coefficients for the divalents metals were in good agreement with experimental results.
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The application of multivariate analysis to spectrophotometric (UV) data was explored for distinguishing extracts of cachaça woods commonly used in the manufacture of casks for aging cachaças (oak, cabreúva-parda, jatobá, amendoim and canela-sassafrás). Absorbances close to 280 nm were more strongly correlated with oak and jatobá woods, whereas absorbances near 230 nm were more correlated with canela-sassafrás and cabreúva-parda. A comparison between the spectrophotometric model and the model based on chromatographic (HPLC-DAD) data was carried out. The spectrophotometric model better explained the variance data (PC1 + PC2 = 91%) exhibiting potential as a routine method for checking aged spirits.
Resumo:
Glycerol, a co-product of biodiesel production, was used as a carbon source for the kinetics studies and production of biosurfactants by P. aeruginosa MSIC02. The highest fermentative parameters (Y PX = 3.04 g g-1; Y PS = 0.189 g g-1, P B = 31.94 mg L-1 h-1 and P X = 10.5 mg L-1 h-1) were obtained at concentrations of 0.4% (w/v) NaNO3 and 2% (w/v) glycerol. The rhamnolipid exhibited 80% of emulsification on kerosene, surface tension of 32.5 mN m-1, CMC = 28.2 mg L-1, C20 (concentration of surfactant in the bulk phase that produces a reduction of 20 dyn/cm in the surface tension of the solvent) = 0.99 mg L-1, Γm (surface concentration excess) = 2.4 x 10-26 mol Å-2 and S (surface area) = 70.4 Ų molecule-1 with solutions containing 10% NaCl. A mathematical model based on logistic equation was considered to representing the process. Model parameters were estimated by non-linear regression method. This approach was able to give a good description of the process.
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This report describes a simple, inexpensive and highly effective instructional model based on the use of a tablet device to enable the real-time projection of the instructor's digitally handwritten annotations to teach chemistry in undergraduate courses. The projection of digital handwriting allows the instructor to build, present and adapt the class contents in a dynamic fashion and to save anything that is annotated or displayed on the screen for subsequent sharing with students after each session. This method avoids the loss of continuity and information that often occurs when instructors switch between electronic slides and white/chalk board during lessons. Students acknowledged that this methodology allows them to follow the instructor's cognitive process and the progressive development of contents during lectures as the most valuable aspect of the implemented instructional model.
Resumo:
Varastoihin sitoutuu yrityksissä paljon arvokasta pääomaa ja varastojen hallinnan osaaminen on noussut yhdeksi kilpailueduksi liiketoiminnassa. Varastoinnilla pyritään suojautumaan puutetilanteilta ja ylläpitämään haluttu palveluaste. Tutkielmassa selvitetään case yrityksen varastojen hallinnan nykytila ja nostetaan esille varastojen hallinnan ongelmatilanteet. Työn tavoitteena on muodostaa organisaation johdolle kokonaiskuva case yrityksen varastoista ja varastoinnin nykytilasta. Työ toteutetaan tapaustutkimuksena, ja aineisto kerätään organisaation henkilökunnasta valituille henkilöille suoritetuilla haastatteluilla. Haastatteluilla saadaan selville varastojen hallinnan toimintamallit ja toiminnan ongelmakohdat varastopaikkakunnilla. Työn tuloksena muodostetaan kokonaiskuva yrityksen varastotoiminnoista ja saadaan selville ongelmien taustalla olevat syyt. Ongelmien perusteella luodaan malli kehitystyön etenemiselle. Lopuksi työssä esitetään toimenpide- ehdotuksia varastojen hallinnan toimintojen jatkokehittämiseen.
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Tässä diplomityössä tarkastellaan tietomallintamista eng. BIM (Building Information Modeling) LVI-suunnittelun näkökulmasta sekä esitellään tietomallintamisen vaikutuksia ja hyötyjä suunnitteluprosessiin. Tietomallintaminen mahdollistaa esimerkiksi LVI-suunnittelijan tuottaman määräluettelon 3D-mallista, jonka seurauksena eri toimijoiden väliset rajapinnat tulevat luultavasti kokemaan muutoksia. Työssä vertaillaan käsin laskettuja ja 3D-mallista tuotettuja määräluetteloita toisiinsa. Työhön sisällytetään myös urakoitsijoiden haastatteluja, joissa pyritään selvittämään heidän näkemyksiään suunnittelijan tuottamiin määrätietoihin.
Resumo:
The topic of this thesis is the simulation of a combination of several control and data assimilation methods, meant to be used for controlling the quality of paper in a paper machine. Paper making is a very complex process and the information obtained from the web is sparse. A paper web scanner can only measure a zig zag path on the web. An assimilation method is needed to process estimates for Machine Direction (MD) and Cross Direction (CD) profiles of the web. Quality control is based on these measurements. There is an increasing need for intelligent methods to assist in data assimilation. The target of this thesis is to study how such intelligent assimilation methods are affecting paper web quality. This work is based on a paper web simulator, which has been developed in the TEKES funded MASI NoTes project. The simulator is a valuable tool in comparing different assimilation methods. The thesis contains the comparison of four different assimilation methods. These data assimilation methods are a first order Bayesian model estimator, an ARMA model based on a higher order Bayesian estimator, a Fourier transform based Kalman filter estimator and a simple block estimator. The last one can be considered to be close to current operational methods. From these methods Bayesian, ARMA and Kalman all seem to have advantages over the commercial one. The Kalman and ARMA estimators seems to be best in overall performance.
Resumo:
Tämän tutkimuksen tavoitteena oli rakentaa kustannuslaskentamalli, jota hyödynne-tään varastopalvelutoimintojen kustannusten tarkastelussa. Tavoitteena oli määrittää ”hintalaput” varaston eri toiminnoille eli selvittää minkä tyyppisiä resursseja toiminnot kuluttavat ja kuinka paljon. Lisäksi mallin tuloksien perusteella pyrittiin kartoittamaan tekijöitä joihin puuttumalla varastopalveluiden kustannustehokkuutta voitaisiin ke-hittää. Rakennettava laskentamalli perustui toimintolaskentaan. Tutkimus jakautui teoria- ja empiiriaosuuteen. Teoriaosuudessa käytiin läpi perinteistä kustannuslaskentaa ja toi-mintolaskentaa sekä verrattiin niitä keskenään. Teoriaosuudessa käytiin läpi myös toimintoperusteiden kustannuslaskentamallin rakentamisen vaiheet sekä perehdyttiin yleisimpiin varastopalvelutoimintoihin ja niiden kustannuslajeihin. Empiiriaosuudessa tutustuttiin Case-yrityksen varastointitoimintoihin, sen kustannuslaskennan nyky-tilaan ja kehityskohteisiin. Lopuksi laskentamallia testattiin yrityksen varastotoimin-toihin. Tutkimuksen tuloksena rakennetun laskentamallin todettiin antavan ymmärrettävää ja analyyttistä tietoa toimintojen ja laskentakohteiden kustannuksista. Laskentamallin tuloksien perusteella päästiin paremmin kiinni kustannusten aiheuttajiin ja tuloksia todettiin voitavan hyödyntää kustannustehokkuuden kehittämisessä. Suurena etuna voitiin täten pitää lisääntynyttä kustannustietoisuutta.
Resumo:
There are small amounts of valuable metals, such as indium, gallium and germanium, in zinc process solutions. Their solvent extraction was studied in this work in sulphate solutions containing zinc and other metals present in industrial solutions. It was discovered, that a commercial bis(2-ethylhexyl)phosphate (D2EHPA) extractant can be used to extract indium and gallium. Indium was extracted separately at a higher acid concentration than gallium. Zinc was co-extracted faster than gallium and almost as much as gallium at the same pH. However, the scrubbing of zinc was possible using a dilute sulphuric acid and a short contact time while gallium losses were small. Both indium and gallium were stripped with sulphuric acid. Germanium was extracted with 5,8-diethyl-7-hydroxydodecane-6-oxime with the commercial name of LIX 63. Unlike other metals in the solution the extraction of germanium increased with different extractants as the acidity increased. Germanium extraction isotherm was measured for a 125 g/L sulfuric acid solution. The loaded organic phase was washed with pure water. It removed the co-extracted acid and part of the germanium and extracted impurities such as iron and copper. Germanium was stripped using a NaOH solution. A process model utilizing own experimentally determined extraction, scrubbing and stripping isotherms was made with HSC Sim software developed by Outotec Oyj. The model based on McCabe–Thiele diagrams was used in sizing the necessary amount of stages and phase ratios in a recovery process. It was concluded, that indium, gallium and germanium can be recovered in the process from a feed where their concentrations are low (<300 ppm). In an example case the feed contained also more than 20 g/L zinc and 2–8 g/L iron, aluminium and copper. The recoveries of indium, gallium and germanium were more than 90 % when 1–3 stages were used in each extraction, scrubbing and stripping section. Since the number of stages is small mixer-settlers would be well suited for this purpose.
Resumo:
The objective of the work has been to study why systems thinking should be used in combination with TQM, what are the main benefits of the integration and how it could best be done. The work analyzes the development of systems thinking and TQM with time and the main differences between them. The work defines prerequisites for adopting a systems approach and the organizational factors which embody the development of an efficient learning organization. The work proposes a model based on combination of an interactive management model and redesign to be used for application of systems approach with TQM in practice. The results of the work indicate that there are clear differences between systems thinking and TQM which justify their combination. Systems approach provides an additional complementary perspective to quality management. TQM is focused on optimizing operations at the operational level while interactive management and redesign of organization are focused on optimization operations at the conceptual level providing a holistic system for value generation. The empirical study demonstrates the applicability of the proposed model in one case study company but its application is tenable and possible also beyond this particular company. System dynamic modeling and other systems based techniques like cognitive mapping are useful methods for increasing understanding and learning about the behavior of systems. The empirical study emphasizes the importance of using a proper early warning system.
Resumo:
In this Thesis the interaction of an electromagnetic field and matter is studied from various aspects in the general framework of cold atoms. Our subjects cover a wide spectrum of phenomena ranging from semiclassical few-level models to fully quantum mechanical interaction with structured reservoirs leading to non-Markovian open quantum system dynamics. Within closed quantum systems, we propose a selective method to manipulate the motional state of atoms in a time-dependent double-well potential and interpret the method in terms of adiabatic processes. Also, we derive a simple wave-packet model, based on distributions of generalized eigenstates, explaining the finite visibility of interference in overlapping continuous-wave atom lasers. In the context of open quantum systems, we develop an unraveling of non-Markovian dynamics in terms of piecewise deterministic quantum jump processes confined in the Hilbert space of the reduced system - the non-Markovian quantum jump method. As examples, we apply it for simple 2- and 3-level systems interacting with a structured reservoir. Also, in the context of ion-cavity QED we study the entanglement generation based on collective Dicke modes in experimentally realistic conditions including photonic losses and an atomic spontaneous decay.