Splat-based surface reconstruction from defect-laden point sets

We introduce a method for surface reconstruction from point sets that is able to cope with noise and outliers. First, a splat-based representation is computed from the point set. A robust local 3D RANSAC-based procedure is used to filter the point set for outliers, then a local jet surface - a low-degree surface approximation - is fitted to the inliers. Second, we extract the reconstructed surface in the form of a surface triangle mesh through Delaunay refinement. The Delaunay refinement meshing approach requires computing intersections between line segment queries and the surface to be meshed. In the present case, intersection queries are solved from the set of splats through a 1D RANSAC procedure

Propriedades estruturais e microestruturais de manganitas dopadas com cobre

We report a structural study on polycrystalline La0.86Sr0.14Mn1-y Cu yO3+delta samples (y = 0, 0.05, 0.10, 0.15, 0.20) using refinement of powder X-ray diffraction data and analysis of scanning electron microscopy images. It is found that the structure remains rhombohedral through the whole series, with a decrease in the average Mn-Mn bond distances, slight variations in Mn-O-Mn angle and reduction in the unit cell volume with increasing Cu amounts. The values of Mn-Mn distances suggest compact structures with d within ±1%. Scanning electron microscopy images reveal homogeneous microstructure in all samples, besides a trend for smaller grains and larger porosity with increasing Cu content.

Síntese da hidroxiapatita e refinamento estrutural por difração de raios-x

A sample of hydroxyapatite was synthesized and its crystalline structure was analyzed by X-ray diffraction by means of the Rietveld method. Two functions were used to fit the peak profiles, modified Voigt (TCHZ) and Pearson VII. The occupational factors and lattice parameters obtained by both models show that the sample does not contain relevant cationic substitutions. The interatomic distances from Ca1 to oxygens O1, O2 and O3 were adequate for a pure hydroxyapatite without defect at site Ca1. Besides, the use of multiple lines in planes (300) and (002) associated with the model Pearson VII resulted in good agreement with the TCHZ model with respect to the size-strain effectswith an ellipsoidal shape of crystallites. In conclusion, the procedures adopted in the synthesis of hydroxyapatite produced a pure and crystalline material. The experimental results of transmission electron microscopy confirmed the predicted shape of crystals.

Análise cristalográfica da solução sólida com estrutura tipo Tungstênio Bronze de niobato de potássio e estrôncio dopado com ferro

Solid solution of iron doped potassium strontium niobate with KSr2(FeNb4)O15-Δ stoichiometry was prepared by high efficiency ball milling method. Structural characterization was carried out by X-ray diffraction. Crystalline structure was analyzed by the Rietveld refinements using the FullProf software. The results showed a tetragonal system with the tetragonal tungsten bronze structure - TTB (a = 12.4631 (2) Å and c = 3.9322 (6) Å, V = 610.78 (2) ų). In this work, the sites occupancy by the K+, Sr2+ and Fe3+ cations on the TTB structure were determined. NbO6 polihedra distortion and its correlation with the theoretical polarization are discussed.

Síntese e caracterização de CaZrO3 e BaZrO3 nanoestruturados

In this work, nanostructured samples of barium zirconate (BaZrO3) and calcium zirconate (CaZrO3) were synthesized by the gel-combustion method, using glycine as fuel. The ceramic powders were calcined at 550 °C for 2 h and subsequently heat treated at 1350 °C for 10 min (fast-firing). The X-ray diffraction technique was employed to identify and characterize the crystalline phases present in the synthesized powders, using the Rietveld method. Monophasic nanostructured samples of BaZrO3 and CaZrO3 presenting average crystallite sizes of around 8.5 and 10.3 nm, respectively, were found after fast-firing.

A regra de Bent contextualiza a força da ligação de hidrogênio em clusters trimoleculares

This article presents a theoretical study of the molecular properties of trimolecular clusters of CnHm∙∙∙HCN∙∙∙HX formed by the ϖ∙∙∙H and n∙∙∙H hydrogen bonds. The interaction strengths of these interactions are in line with the variations in s-character, and independently, the red-shift rise whether stronger or weaker bound systems are carried out. This behavior was justified via NBO analysis and supported by Bent´s rule, wherein the greater variations in s-character of X are in good agreement with larger red-shifts and vice-versa. To conclude, the refinement of the supermolecule approach and NBO binding energies also corroborate in this regard.

ATRIBUIÇÃO DA ESTEREOQUÍMICA DA α-SANTONINA ATRAVÉS DAS MEDIDAS DO ACOPLAMENTO DIPOLAR RESIDUAL

The measurement of nuclear magnetic resonance parameters in an anisotropic media, such as residual dipolar coupling (RDC), has proven to be an excellent methodology for the refinement of chemical structures, being used as a complementary tool in the determination of the relative configuration, conformation, and constitution of organic compounds. In this study, we applied this methodology to determine the relative configuration of α-santonin, a natural product with four stereocenters, while assigning its prochiral methylene protons using only the RDCs obtained in a polyacrylonitrile polymer gel swollen in DMSO-d6.

CFD Simulation of Two-phase and Three-phase Flows in Internal-loop Airlift

Airlift reactors are pneumatically agitated reactors that have been widely used in chemical, petrochemical, and bioprocess industries, such as fermentation and wastewater treatment. Computational Fluid Dynamics (CFD) has become more popular approach for design, scale-up and performance evaluation of such reactors. In the present work numerical simulations for internal-loop airlift reactors were performed using the transient Eulerian model with CFD package, ANSYS Fluent 12.1. The turbulence in the liquid phase is described using κ- ε the model. Global hydrodynamic parameters like gas holdup, gas velocity and liquid velocity have been investigated for a range of superficial gas velocities, both with 2D and 3D simulations. Moreover, the study of geometry and scale influence on the reactor have been considered. The results suggest that both, geometry and scale have significant effects on the hydrodynamic parameters, which may have substantial effects on the reactor performance. Grid refinement and time-step size effect have been discussed. Numerical calculations with gas-liquid-solid three-phase flow system have been carried out to investigate the effect of solid loading, solid particle size and solid density on the hydrodynamic characteristics of internal loop airlift reactor with different superficial gas velocities. It was observed that averaged gas holdup is significantly decreased with increasing slurry concentration. Simulations show that the riser gas holdup decreases with increase in solid particle diameter. In addition, it was found that the averaged solid holdup increases in the riser section with the increase of solid density. These produced results reveal that CFD have excellent potential to simulate two-phase and three-phase flow system.

Numerical Investigation of Flow Past a Circular Cylinder and in a Staggered Tube Bundle Using Various Turbulence Models

Transitional flow past a three-dimensional circular cylinder is a widely studied phenomenon since this problem is of interest with respect to many technical applications. In the present work, the numerical simulation of flow past a circular cylinder, performed by using a commercial CFD code (ANSYS Fluent 12.1) with large eddy simulation (LES) and RANS (κ - ε and Shear-Stress Transport (SST) κ - ω! model) approaches. The turbulent flow for ReD = 1000 & 3900 is simulated to investigate the force coefficient, Strouhal number, flow separation angle, pressure distribution on cylinder and the complex three dimensional vortex shedding of the cylinder wake region. The numerical results extracted from these simulations have good agreement with the experimental data (Zdravkovich, 1997). Moreover, grid refinement and time-step influence have been examined. Numerical calculations of turbulent cross-flow in a staggered tube bundle continues to attract interest due to its importance in the engineering application as well as the fact that this complex flow represents a challenging problem for CFD. In the present work a time dependent simulation using κ – ε, κ - ω! and SST models are performed in two dimensional for a subcritical flow through a staggered tube bundle. The predicted turbulence statistics (mean and r.m.s velocities) have good agreement with the experimental data (S. Balabani, 1996). Turbulent quantities such as turbulent kinetic energy and dissipation rate are predicted using RANS models and compared with each other. The sensitivity of grid and time-step size have been analyzed. Model constants sensitivity study have been carried out by adopting κ – ε model. It has been observed that model constants are very sensitive to turbulence statistics and turbulent quantities.

Romanssien ja runouden aikakausi. Thomas Warton keskiaikaa määrittelemässä 1750–1790

Tutkimukseni käsittelee keskiajan nousua historian tärkeäksi periodiksi 1700-luvun Englannissa näkökulmanaan Thomas Wartonin (1726–1790) kirjoitukset. Warton oli Oxfordin yliopistossa toiminut oppinut antikvaari. Wartonin pääteos History of English Poetry (1774–1781) ei nimestään huolimatta ollut moderni kirjallisuushistoria vaan 1000–1500-luvun kirjoitettua kulttuuria laajasti käsitellyt vernakulaariin kirjallisuuteen pohjautunut esitys. Warton ja hänen lähipiiriinsä kuuluneet tutkijat tarjoavat erityisen mahdollisuuden tarkastella, miten käsitys keskiajasta omana aikakautenaanmuodostui 1700-luvun lopulla. Tutkin Wartonin ja hänen aikalaistensa toisen vuosituhannen alusta kirjoittamia arvioita Michel de Certeaun historiografisen operaation käsitteen avulla. Se koostuu kolmesta vaiheesta: Alue määrittelee sosiaaliset riippuvuussuhteet ja vaikuttimet, jotka ohjaavat tutkimusta. Käytäntö viittaa siihen, miten historioitsija valitsee materiaalinsa ja muokkaa siitä historiankirjoituksena hahmottuvan kokonaisuuden. Lopuksi kirjoitus konkreettisena ja fyysisenä ilmiönä luo illuusion lopullisuudesta ja huonosti sopivien osien yhteenkuuluvuudesta. de Certeaun teoria soveltuu paremmin vanhemman historiankirjoituksen ja oppineisuuden tarkasteluun kuin historiantutkimuksen narratiiveja analysoivat teokset, koska se kontekstualisoi laajemmin historiankirjoitukseen vaikuttavat ilmiöt. Thomas Warton ja muut 1700-luvun puolivälin oppineet määrittelivät keskiajan fiktiivisten tekstien avulla. Warton tutustui tarkasti romansseihin ja kronikoihin. Erityisen suuri merkitys keskiajan hahmottamisen kannalta oli Geoffrey Monmouthilaisen kronikalla Historia regum britanniae, joka esitteli Englannin myyttisen varhaisen historian yhdistämällä Rooman ja oman kansallisen perinteen. Geoffreyn kronikan avulla Warton huomasi keskiaikaisten tarinoiden laajan vaikutuksen; hän kirjoitti erityisesti kuningas Arthuriin liittyneiden kertomusten merkityksestä, joka jatkui aina 1500-luvulle asti. Näin Warton löysi antiikin perinteelle haastajan keskiaikaisesta kulttuurista. Wartonin tapa esitellä keskiaikaa perustui osittain valistusajan sulavasti kirjoitetuille universaalihistorioille, osittain oppineelle luettelomaiselle esitystavalle. Käytännössä Wartonin pitkät johdantotutkielmat kuitenkin johdattavat lukijaa keskeisiin teemoihin. Niitä ovat mielikuvituksen väheneminen uusimmassa kirjallisuudessa ja toisaalta hienostuneisuuden ja tiedon kasvu. Warton ei missään vaiheessa kerro, liittyvätkö nämä teemat yhteen, mutta tulkintani mukaan ne liittyivät. Warton ajatteli kirjallisuuden menettäneen olennaisen mielikuvituksen samaan aikaan, kun yhteiskunta oli kehittynyt. Tämä auttaa hahmottamaan koko kirjallisuuden historiaa: Warton etsi alkuperäistä mielikuvitusta niin antiikin Kreikasta, Orientista kuin muinaisesta Skandinaviasta. History of English Poetry ei pohtinut vain kirjallisuuden ja yhteiskunnan suhdetta, sillä Warton ajatteli voivansa tutkia keskiajan yhteiskuntaa kronikoiden ja romanssien avulla. Hänen käsityksensä feodalismista, hovien elämästä ja keskiaikaisista tavoista perustuivat niihin. Warton ei huomannut, että hänen käyttämänsä lähteet olivat tietoisia kirjallisia konstruktioita vaan hän piti niitä totuudenmukaisina kuvauksina. Toisaalta Wartonin tulkintaan heijastuivat myös 1700-luvun käsitykset yhteiskunnasta. Keskiajan lähteiden kuvaukset ja 1700-luvun ideaalit vaikuttivat lopulta siihen, millaiseksi populaari kuva keskiajasta kehittyi.

Spare part business analysis and development

The purpose of this Thesis was to comprehensively analyze and develop the spare part business in Company Oy’s five biggest product groups by searching development issues related to single spare parts’ supply chains as well as the spare part business process, make implementation plans for them and implement the plans when possible. The items were classified based on special characteristics of spare parts and on their actual sales volumes. The created item classes were examined for finding improvement possibilities. Management strategies for classified items were suggested. Vendors and customers were analyzed for supporting the comprehensive supply network development work. The effectiveness of the current spare part business process was analyzed in co-operation with the spare part teams in three business unit locations. Several items were taken away from inventories as uselessly stocked items. Price list related to core items with one of the main product group’s core item manufacturer was suggested to be expanded in Town A. Refinement equipment seal item supply chain management was seen important to develop in Town B. A new internal business process model was created for minimizing and enhancing the internal business between Company’s business units. SAP inventory reports and several other features were suggested to be changed or developed. Also the SAP data material management was seen very important to be developed continuously. Many other development issues related to spare parts’ supply chains and the work done in the business process were found. The need for investigating the development possibilities deeper became very clear during the project.

Methods for construction and analysis of computational models in systems biology : applications to the modelling of the heat shock response and the self-assembly of intermediate filaments

Systems biology is a new, emerging and rapidly developing, multidisciplinary research field that aims to study biochemical and biological systems from a holistic perspective, with the goal of providing a comprehensive, system- level understanding of cellular behaviour. In this way, it addresses one of the greatest challenges faced by contemporary biology, which is to compre- hend the function of complex biological systems. Systems biology combines various methods that originate from scientific disciplines such as molecu- lar biology, chemistry, engineering sciences, mathematics, computer science and systems theory. Systems biology, unlike “traditional” biology, focuses on high-level concepts such as: network, component, robustness, efficiency, control, regulation, hierarchical design, synchronization, concurrency, and many others. The very terminology of systems biology is “foreign” to “tra- ditional” biology, marks its drastic shift in the research paradigm and it indicates close linkage of systems biology to computer science. One of the basic tools utilized in systems biology is the mathematical modelling of life processes tightly linked to experimental practice. The stud- ies contained in this thesis revolve around a number of challenges commonly encountered in the computational modelling in systems biology. The re- search comprises of the development and application of a broad range of methods originating in the fields of computer science and mathematics for construction and analysis of computational models in systems biology. In particular, the performed research is setup in the context of two biolog- ical phenomena chosen as modelling case studies: 1) the eukaryotic heat shock response and 2) the in vitro self-assembly of intermediate filaments, one of the main constituents of the cytoskeleton. The range of presented approaches spans from heuristic, through numerical and statistical to ana- lytical methods applied in the effort to formally describe and analyse the two biological processes. We notice however, that although applied to cer- tain case studies, the presented methods are not limited to them and can be utilized in the analysis of other biological mechanisms as well as com- plex systems in general. The full range of developed and applied modelling techniques as well as model analysis methodologies constitutes a rich mod- elling framework. Moreover, the presentation of the developed methods, their application to the two case studies and the discussions concerning their potentials and limitations point to the difficulties and challenges one encounters in computational modelling of biological systems. The problems of model identifiability, model comparison, model refinement, model inte- gration and extension, choice of the proper modelling framework and level of abstraction, or the choice of the proper scope of the model run through this thesis.

On the impact of rigorous approaches on the quality of development

Software systems are expanding and becoming increasingly present in everyday activities. The constantly evolving society demands that they deliver more functionality, are easy to use and work as expected. All these challenges increase the size and complexity of a system. People may not be aware of a presence of a software system, until it malfunctions or even fails to perform. The concept of being able to depend on the software is particularly significant when it comes to the critical systems. At this point quality of a system is regarded as an essential issue, since any deficiencies may lead to considerable money loss or life endangerment. Traditional development methods may not ensure a sufficiently high level of quality. Formal methods, on the other hand, allow us to achieve a high level of rigour and can be applied to develop a complete system or only a critical part of it. Such techniques, applied during system development starting at early design stages, increase the likelihood of obtaining a system that works as required. However, formal methods are sometimes considered difficult to utilise in traditional developments. Therefore, it is important to make them more accessible and reduce the gap between the formal and traditional development methods. This thesis explores the usability of rigorous approaches by giving an insight into formal designs with the use of graphical notation. The understandability of formal modelling is increased due to a compact representation of the development and related design decisions. The central objective of the thesis is to investigate the impact that rigorous approaches have on quality of developments. This means that it is necessary to establish certain techniques for evaluation of rigorous developments. Since we are studying various development settings and methods, specific measurement plans and a set of metrics need to be created for each setting. Our goal is to provide methods for collecting data and record evidence of the applicability of rigorous approaches. This would support the organisations in making decisions about integration of formal methods into their development processes. It is important to control the software development, especially in its initial stages. Therefore, we focus on the specification and modelling phases, as well as related artefacts, e.g. models. These have significant influence on the quality of a final system. Since application of formal methods may increase the complexity of a system, it may impact its maintainability, and thus quality. Our goal is to leverage quality of a system via metrics and measurements, as well as generic refinement patterns, which are applied to a model and a specification. We argue that they can facilitate the process of creating software systems, by e.g. controlling complexity and providing the modelling guidelines. Moreover, we find them as additional mechanisms for quality control and improvement, also for rigorous approaches. The main contribution of this thesis is to provide the metrics and measurements that help in assessing the impact of rigorous approaches on developments. We establish the techniques for the evaluation of certain aspects of quality, which are based on structural, syntactical and process related characteristics of an early-stage development artefacts, i.e. specifications and models. The presented approaches are applied to various case studies. The results of the investigation are juxtaposed with the perception of domain experts. It is our aspiration to promote measurements as an indispensable part of quality control process and a strategy towards the quality improvement.

Siirtohinnoitteluperiaatteet johtamisen apuvälineenä: case-tutkimus

Tämä tutkimus tarkastelee siirtohinnoittelun periaatteita ja sen taustalla vaikuttavia tekijöitä. Tutkielman tavoitteena on tutkia kohdeyrityksen nykyistä siirtohinnoittelua ja laatia sille periaatteet sen yksiköiden väliselle sisäiselle kaupalle. Tarkoituksena on kehittää siirtohinnoitteluperiaatteet, jotka auttavat johtoa liiketoiminnan eteenpäin viemisessä niin, että nuo periaatteet ovat samalla oikeudenmukaiset kohdeyrityksen eri osapuolille. Tutkimus on luonteeltaan kvalitatiivinen, teoreettinen ja kuvaileva case-tutkimus. Se tuo esille teoriaosuudessa eri siirtohinnoitteluvaihtoehtoja ja pohtii analyyttisesti niiden hyötyjä ja haittoja. Teoriaosuus perustuu kattavalle kirjallisuudelle, jonka avulla otetaan huomioon tekijöitä, jotka vaikuttavat siirtohinnoitteluprosessin taustalla. Tutkielman empiirinen aineisto kerättiin haastattelemalla kohdeyrityksen ylintä johtoa. Haastatteluiden rakenne oli luonteeltaan puolistrukturoitu. Lisäksi käytiin aiheeseen liittyvää keskustelua useaan otteeseen kohde-yrityksen talouspäällikön kanssa sekä tehtiin tutustumiskäynti erääseen osuuskuntaan, jossa kohdeyritys on osakkaana. Vierailu perustui osuuskunnan talouspäällikön pitämään esitykseen ja sen aikana käytyyn keskusteluun. Haastattelut tehtiin kevään 2012 aikana. Tutkimuksen perusteella siirtohinnoittelu on monimutkainen prosessi, jossa samanaikaisesti ei voida saavuttaa kaikkia siltä vaadittuja tavoitteita. Siirtohinnoitteluperiaatteita laadittaessa tulee ottaa etenkin huomioon 1) organisaation liiketoiminnan luonne 2) yksiköiden luonne, 3) vaihdettavien tuotteiden luonne, 4) erilaisten hintojen saatavuus sekä 5) suorituskyvyn mittaus ja arviointi. Tämä tutkimus suosittelee kohdeyrityksen tulos-yksiköille yleisesti mukautetun markkinaperusteisen siirtohinnoittelu-vaihtoehdon käyttöönottoa. Jalostustoimintaa vaativien tuotteiden sisäiselle kaupalle tutkimus suosittelee kustannusperusteisen vaihtoehdon noudattamista.

Scheduling of guarded command based models

Formal methods provide a means of reasoning about computer programs in order to prove correctness criteria. One subtype of formal methods is based on the weakest precondition predicate transformer semantics and uses guarded commands as the basic modelling construct. Examples of such formalisms are Action Systems and Event-B. Guarded commands can intuitively be understood as actions that may be triggered when an associated guard condition holds. Guarded commands whose guards hold are nondeterministically chosen for execution, but no further control flow is present by default. Such a modelling approach is convenient for proving correctness, and the Refinement Calculus allows for a stepwise development method. It also has a parallel interpretation facilitating development of concurrent software, and it is suitable for describing event-driven scenarios. However, for many application areas, the execution paradigm traditionally used comprises more explicit control flow, which constitutes an obstacle for using the above mentioned formal methods. In this thesis, we study how guarded command based modelling approaches can be conveniently and efficiently scheduled in different scenarios. We first focus on the modelling of trust for transactions in a social networking setting. Due to the event-based nature of the scenario, the use of guarded commands turns out to be relatively straightforward. We continue by studying modelling of concurrent software, with particular focus on compute-intensive scenarios. We go from theoretical considerations to the feasibility of implementation by evaluating the performance and scalability of executing a case study model in parallel using automatic scheduling performed by a dedicated scheduler. Finally, we propose a more explicit and non-centralised approach in which the flow of each task is controlled by a schedule of its own. The schedules are expressed in a dedicated scheduling language, and patterns assist the developer in proving correctness of the scheduled model with respect to the original one.