This research aims to explore new ways of assessing energy performance within housing units. The mainobjective of this work is to propose a heat dynamics model based on monitoring data, to contribute towardsan energy-efficient transition in the building sector. An extensive study on the available mathematical and statistical tools is described in order to determine aholistic solution, found in grey-box models. This model approach offers the possibility of understandingmultivariate systems, which can be applied to a housing-unit heat flow dynamics. Through the iterative process of testing each possible model, this work determines the one with bestexplanatory power, defining the thermal characteristics of the studied housing unit. This method allows thedetection of underperforming dwellings among constructions with high energy-efficiency standards. This investigation reflects the feasibility of employing grey-box models to predict the dynamics of heatrelated systems. Moreover, it sets the basis for new ways of employing the monitoring data of dwellings. / Denna forskning syftar till att utforska nya sätt att bedöma energiprestanda inom bostäder. Huvudsyftetmed detta arbete är att föreslå en värmedynamikmodell baserad på övervakningsdata för att bidra till enenergieffektiv övergång inom byggsektorn. En omfattande studie av tillgängliga matematiska och statistiska verktyg beskrivs för att bestämma enhelhetslösning, som finns i gråboxmodeller. Denna modellstrategi ger möjlighet att förstå multivariatasystem, som kan tillämpas på en hushålls värmedynamik. Genom den iterativa processen att testa varje möjlig modell bestämmer detta arbete den med bästförklarande kraft, och definierar de studerade husenhetens termiska egenskaper. Denna metod gör detmöjligt att upptäcka underpresterande bostäder bland anläggningar med hög energieffektivitetsstandard. Denna undersökning återspeglar möjligheten att använda gråboxmodeller för att förutsäga dynamiken ivärmerelaterade system. Dessutom lägger den grunden för nya sätt att använda övervakningsdata förbostäder.

Hole deviation is one of the most significant problems in drilling applications. Deviated holes result in inefficient blasting and have severe economic impacts due to increased equipment consumption. Conversely, straighter holes help in increasing production scales and reduce operational costs. The reason for hole deviations could range from anisotropic behavior of the rocks being drilled to the behavior of the drill string under the action of imposed forces. Deviations caused due to rock anisotropy are complex in nature and non-controllable to some extent but deviations due to mechanics of drill strings can be controlled as they lie in the operator’s area of influence. In this thesis, a 2D mathematical model is constructed which predicts the bending behavior of the drill rod and the model is further extended to predict the buckled profile of the entire drill string. Two bit state parameters are defined which help in better characterization of hole deviation and understanding of deflected state of the drill bit. Epiroc’s drilling data is inserted in the model developed and the buckled profile of the drill string is studied. The developed model is used to further understand the effect of various drilling parameters like bit thrust, angle of inclination, hole length, etc. on hole deviation. Through the results it was concluded that the bending stiffness of the drill rods is the most critical parameter influencing hole deviation for Epiroc’s drilling data and drill string setup. Finally, potential improvements and techniques to validate results obtained from the mathematical model are proposed. / Hålavvikelse är ett av de mest avgörande problemen i borrapplikationer. Hålavvikelse resulterar i ineffektiv sprängning och får allvarliga ekonomiska konsekvenser på grund av ökad utrustningskonsumtion. Omvänt hjälper rakare hål att öka produktionsskalorna och minska driftskostnaderna. Anledningen till hålavvikelser variera från anisotropi hos bergformationerna som borras till borrsträngens beteende under påverkan av pålagda krafter. Avvikelser orsakade på grund av berganisotropi är komplexa till sin natur och kan inte kontrolleras till viss del, men avvikelser på grund av mekanik i borrsträngar kan kontrolleras eftersom de ligger i operatörens inflytandeområde. I denna avhandling konstrueras en matematisk 2D-modell som förutsäger borrstångens böjningsbeteende och modellen utökas ytterligare för att förutsäga den böjda profilen för hela borrsträngen. Två olika borrkroneparametrar definieras för att bättre karakterisera hålavvikelsen och förstå borrkronans böjning. Epirocs borrsträngsdata används i den utvecklade modellen och borrsträngens böjda profil studeras. Den utvecklade modellen används för att ytterligare förstå effekten av hålavvikelse för olika borrparametrar som kraften på borrkronan, lutningsvinkel, hållängd etc. Utifrån resultaten drogs slutsatsen att borrsträngens böjstyvhet är den mest kritiska parametern som påverkar hålavvikelsen för Epirocs borrdata och borrsträngsinstallation. Slutligen föreslås potentiella förbättringar och tekniker för att validera resultat som erhållits från den matematiska modellen.

No / Narrowband path loss measurements are reported for the vehicle-to-vehicle channel between a transmitting antenna 50 cm above the ground and a car-roof-mounted receiver array. Calibration procedures and measurement results are reported for typical urban, suburban and rural-motorway environments and compared with existing mobile channel models to give insight into the large-scale fading behavior in the vehicle-to-vehicle channel.

Selbstreproduktion ist eines der Kennzeichen aller lebenden Organismen. Der Zellzyklus dient der Selbstreproduktion in einzelligen Organismen. In mehrzelligen Organismen ist der Zellzyklus darüber hinaus für andere lebenswichtige Prozesse, einschließlich Immunreaktionen, unerlässlich. In dieser Arbeit wird eine Methode entwickelt mit der die Dauer der Zellzyklus Phasen bestimmt werden kann. Kenntnis über die Zellzyklusphasendauer ermöglicht vorherzusagen, wie schnell eine Population von proliferierenden Zellen wachsen wird, oder wie viele neue Zellen pro Stunde in einem Gewebe geboren werden. Im Kapitel 1 dieser Arbeit wird ein Zellzyklusmodell aufgestellt und mit experimentellen Bromdesoxyuridin Daten verglichen. Die Analyse zeigt, dass das Modell gut die experimentelle Kinetik beschreibt, hebt jedoch auch hervor dass einige der Parameter nicht identifiziert werden können. Dieses Problem wird in Kapitel 2 bearbeitet, wo zwei Ansätze erforscht werden, um den Informationsgehalt der Experimente zu erhöhen. In einem ersten Ansatz wird die Theorie der Versuchsplanung angewendet, um optimale Versuchspläne zu bestimmen. In einem zweiten Ansatz wird das übliche Bromdesoxyuridin Protokoll durch ein zweites Nukleosid erweitert. Beide Methoden verbessern in silico erheblich die Genauigkeit und Präzision der Abschätzungen. Im dritten Kapitel wird die Methodik in der Analyse der Keimzentrumsreaktion angewendet. Ein erheblicher Zufluss von Zellen in die dunkle Zone von Keimzentren wird vorhergesagt, und die Ansicht einer extrem schellen Zellteilung im Keimzentrum erscheint in dem Modell als ein Artefakt der Zellmigration. / Self-reproduction is one of the distinguishing marks of living organisms. The cell cycle is the underlying process by which self-reproduction is accomplished in single-celled organisms. In multi-cellular organisms, the cell cycle is in addition indispensable for other vital processes, including immune reactions. In this thesis a method is developed that allows to estimate the time it takes for a dividing cells to complete the CC phases. Knowledge of the CC phase durations allows to predict, for example, how fast a population of proliferating cells will grow in size, or how many new cells are born per hour in a given tissue. In Chapter 1 of this thesis, a cell cycle model with delays and variability in the completion times of each phase is developed. Analytical solutions are derived to describe a common experimental technique used for cell cycle analysis, namely pulse labeling with bromodeoxyuridine (BrdU). Comparison with data shows that the model reproduces closely measured cell cycle kinetics, however also reveals that some of the parameter values cannot be identified. This problem is addressed in Chapter 2. In a first approach, the framework of D-optimal experimental designs is employed, in order to choose optimal sampling schemes. In a second approach, the prevailing protocol with a single nucleoside is modified by adding a second nucleoside analog pulse. Both methods are tested and the results suggest that experimental design can significantly improve parameter estimation. In Chapter 3, the model is applied to the germinal center reaction. A substantial influx of cells into the dark zone of germinal centers is predicted. Moreover the wide-held view of rapid proliferation in germinal centers, appears, under this model, as an artifact of cell migration.

Foot-and-mouth disease virus (FMDV) is a highly infectious virus affecting cloven-hoofed animals. The most prominent of its clinical signs is the development of vesicular lesions on the feet and in or around the mouth, which are a consequence of extensive FMDV-induced epithelial cell death. Currently, there is no certain biological knowledge on why extensive epithelial cell death occurs in some FMDV-infected tissues, but not in others. Using the epithelial tissues of tongue and dorsal soft palate as examples of a tissue where lesions occur and one that does not visibly exhibit FMDV-induced cell death, this work aims to identify the potential drivers of epithelial cell death and survival. A partial differential equation (PDE) model informed by experimental data on epithelial structure, is used to test epithelium thickness and cell layer structure as potential determinants. A second PDE model investigates FMDV-interferon (IFN) dynamics and their impact on the levels of cell death and survival, while an experimental study is undertaken to provide data for model validation. The work carried out casts light on the important role of a variety of factors including FMDV replication, IFN production and release, and IFN antiviral action.

Thesis (MSc)--Stellenbosch University, 2015 / ENGLISH ABSTRACT : In this study we look at the syndemic of substance abuse and drug-related crime in the Western Cape province of South Africa. The intent of this study is to provoke critical thinking about the possibilities systems thinking and system dynamics posses for social and health challenges in a diverse and complex environment like that of South Africa, especially the Western Cape. This study ventures into cross-discipline work between Epidemiology, Biomathematics and System Dynamics, with the hope of encouraging researchers from different fields to collaborate in order to curb the scourge of substance abuse and drug-related crime in South Africa. Substance abuse and the associated health and social hazards such as drug-related crime is a major problem in the Western Cape. Drug-related crime cases reported by the South African Police Services (SAPS) for the Western Cape exhibited a 311.5% growth in the past decade. This highlights how the reduction of substance abuse and drug-related crime within theWestern Cape province, will be an elixir for the safety and development of the communities. The fight against substance abuse has been driven by a multi-sectorial approach involving several government departments, non-governmental organisations and communities. With systems thinking the assumption is that the world is systemic, which means that phenomena is understood to be an emergent property of the interrelated whole. Firstly, using non-linear ordinary differential equations, we formulate a deterministic mathematical model for the substance abuse and drug-related crime syndemic, evaluate the threshold number and use sensitivity analysis to analyze the model. Secondly, a dynamic system, called the Substance Abuse and Drug-related Crime in theWestern Cape (SADC-WC) system is constructed using the STELLA in order to explore and classify the underlying relationships and structures within the substance abuse and drug-related crime system. Both the sensitivity analysis, and the simulations of the SADC-WC system indicate that an increase of successful convictions will have a significant influence on the syndemic, and promise to reduce drug-related crime cases. / AFRIKAANSE OPSOMMING : In hierdie studie ondersoek on die syndemie (‘syndemic’) van dwelmmisbruik en dwelmverwante misdaad in die Wes-Kaap provinsie, in Suid-Afrika. Die moontlikhede wat sistemiese denke en dinamiese sisteme inhou vir sosiale en gesondheid kwale in ’n diverse en komplekse omgewing soos Suid-Afrika, word ondersoek. Hierdie studie waag interdisiplinêre werk tussen Epidemiologie, Biowiskunde en Dinamiese sisteme, met die hoop om navorsers van verskillende velde aan te moedig om saam te werk om die plaag van dwelmmisbruik en dwelm-verwante misdaad in Suid-Afrika te bekamp. Dwelmmisbruik en die gepaardgaande gesondheid en maatskaplike gevare soos dwelmverwante misdaad is ’n groot probleem in dieWes-Kaap. Die SAPD se vermelde dwelmverwante midaad het ’n groei van 311,5% ondergaan in die afgelope dekade, en is aanduidend vir hoe die beheer en beperking van dwelmmisbruik en dwelm-verwante misdaad in die Wes-Kaap provinsie bevordering van beide die veiligheid en ontwikkeling van die gemeenskap sal verseker. Dit beklemtoon hoe die vermindering van dwelmmisbruik en dwelm-verwante misdaad in dieWes-Kaapland, sal ’n elikser vir die veiligheid en ontwikkeling van die gemeenskappe. Die stryd teen dwelmmisbruik is gedryf deur ’n multi-sektorale benadering waarby verskeie regeringsdepartemente, nie-regerings organisasies en gemeenskappe. Stelsels denke en dinamiese sisteme is gebasseur op die aanname, dat die wÃłreld is sistemiese en dat verskynsels verstaan word ten opsigte van die ontluikende eienskap van die omvattende geheel. Eerstens stel ons ’n kompartementele model op wat deur nie-liniêre gewone differensiële vergelykings beskryf kan word vir die dwelmmisbruik en dwelm-verwante misdaad epidemies. Ons evalueer die drumpel getal en gebruik sensitiwiteitsanalise om die parameters van die model te analiseer. Tweedens, is ’n dinamiese sisteem genaamd die Middelmisbruik en dwelmverwante misdaad in dieWes-Kaap (SADC-WC) stelsel gebou met behulp van die STELLA platform om te verken en klassifiseer die onderliggende verhoudings en strukture binne die dwelmmisbruik en dwelm-verwante misdaad stelsel. Beide die sensitiwiteitsanalise, en die simulasies van die SADC-WC stelsel dui aan dat ’n toename in suksesvolle vonisse ’n beduidende invloed op die epidemies sal hê; en beloof om sake van dwelmverwante misdaad te verminder.

<p>In order to understand how the brain functions, under normal as well as pathological conditions, it is important to study the mechanisms underlying information integration. Depending on the nature of an input arriving at a synapse, different strategies may be used by the neuron to integrate and respond to the input. Naturally, if a short train of high-frequency synaptic input arrives, it may be beneficial for the neuron to be equipped with a fast mechanism that is highly sensitive to inputs on a short time scale. If, on the contrary, inputs arriving with low frequency are to be processed, it may be necessary for the neuron to possess slow mechanisms of integration. For example, in certain working memory tasks (e. g. delay-match-to-sample), sensory inputs may arrive separated by silent intervals in the range of seconds, and the subject should respond if the current input is identical to the preceeding input. It has been suggested that single neurons, due to intrinsic mechanisms outlasting the duration of input, may be able to perform such calculations. In this work, I have studied a mechanism thought to be particularly important in supporting the integration of low-frequency synaptic inputs. It is mediated by a cascade of events that starts with activation of group I metabotropic glutamate receptors (mGlu1/5), and ends with a membrane depolarization caused by a current that is mediated by canonical transient receptor potential (TRPC) ion channels. This current, denoted I_TRPC, is the focus of this thesis.</p><p>A specific objective of this thesis is to study the role of I_TRPC in the integration of synaptic inputs arriving at a low frequency, < 10 Hz. Our hypothesis is that, in contrast to the well-studied, rapidly decaying AMPA and NMDA currents, I_TRPC is well-suited for supporting temporal summation of such synaptic input. The reason for choosing this range of frequencies is that neurons often communicate with signals (spikes) around 8 Hz, as shown by single-unit recordings in behaving animals. This is true for several regions of the brain, including the entorhinal cortex (EC) which is known to play a key role in producing working memory function and enabling long-term memory formation in the hippocampus.</p><p>Although there is strong evidence suggesting that I_TRPC is important for neuronal communication, I have not encountered a systematic study of how this current contributes to synaptic integration. Since it is difficult to directly measure the electrical activity in dendritic branches using experimental techniques, I use computational modeling for this purpose. I implemented the components necessary for studying I_TRPC, including a detailed model of extrasynaptic glutamate concentration, mGlu1/5 dynamics and the TRPC channel itself. I tuned the model to replicate electrophysiological in vitro data from pyramidal neurons of the rodent EC, provided by our experimental collaborator. Since we were interested in the role of I_TRPC in temporal summation, a specific aim was to study how its decay time constant (τ_decay) is affected by synaptic stimulus parameters.</p><p>The hypothesis described above is supported by our simulation results, as we show that synaptic inputs arriving at frequencies as low as 3 - 4 Hz can be effectively summed. We also show that τ_decay increases with increasing stimulus duration and frequency, and that it is linearly dependent on the maximal glutamate concentration. Under some circumstances it was problematic to directly measure τ_decay, and we then used a pair-pulse paradigm to get an indirect estimate of τ_decay.</p><p>I am not aware of any computational model work taking into account the synaptically evoked I_TRPC current, prior to the current study, and believe that it is the first of its kind. We suggest that I_TRPC is important for slow synaptic integration, not only in the EC, but in several cortical and subcortical regions that contain mGlu1/5 and TRPC subunits, such as the prefrontal cortex. I will argue that this is further supported by studies using pharmacological blockers as well as studies on genetically modified animals.</p> / QC 20101005

Baigiamajame magistro darbe nagrinėjamos statinės ir dinaminės jėgos veikiančios tiesiaeigiame žingsniniame variklyje (TŽV). Apžvelgiami žingsninių variklių tipai, jų savybės ir charakteristikos. Analizuojamos variklio postūmio ir traukos jėgos bei matematinio modelio sudarymas. Tiriamojoje dalyje tiesiaeigiuose žingsniniuose varikliuose veikiančios jėgos tiriamos sudarant matematinius modelius, visi skaičiavimai atlikti naudojant programinį paketą MATHCAD. Ekperimento metu gautų rezultatų apdorojimui naudojamas programinis paketas DynaMax. Gautos statinės jėgos dedamųjų Fx, veikiančios išilgai judėjimo krypties, ir Fy, veikiančios vertikaliąja ašimi, priklausomybės nuo polių postūmio danties atžvilgiu, keičiant įvairius parametus (poliaus ir danties pločių santykį, magnetinę įtampą, oro tarpą). Taip pat atlikti tyrimai, parodantys kaip kinta dinaminė jėga, esant skirtingoms apvijos maitinimo įtampoms. Teoriniai skaičiavimai palyginti su eksperimentiniais tyrimo rezultatais. Išnagrinėjus teorinius ir praktinius matavimus pateikiamos baigiamojo darbo išvados ir pasiūlymai. Darbą sudaro 6 dalys: įvadas, teorinė dalis, tiriamoji dalis, išvados ir pasiūlymai, literatūra, priedai. Darbo apimtis – 70 psl. teksto be priedų, 45 iliustr., 14 lent., 14 bibliografiniai šaltiniai, 11 internetinių prieigų. Atskirai pridedami darbo priedai. / At the final Master's work dealt with the static and dynamic forces acting linear stepper motor (LSM). Overview of types of stepping motors, their properties and characteristics. Examines the push and pull the engine and the power of the mathematical model. The exploratory part of rectilineal stepping motors operating in the force under investigation for the mathematical models, all calculations performed using the software package MathCAD. Experimentation of the results of treatment using the software package DynaMax. The resulting static force added Fx, acting along the direction of movement, and the Fy in the vertical axis of dependence on the poles pull the tooth, the modification of various parameters (polarity, and the tooth width ratio, magnetic tension, the air space). Studies also showing changes in dynamic forces at different supply voltage windings. Theoretical calculations compared with experimental test results. The examination of the theoretical and practical measurements are presented on the final conclusions and proposals. Structure: introduction, theoretical part, searching part, conclusions and suggestions, references, appendix. Thesis consist of: 70 p. text without extras, 45 pictures, 14 tables, 14 bibliographical entries and 11 internet entries. Appendixes included.

Baigiamajame magistro darbe nagrinėjama iešmo elektros pavara su tiesiaeigiu asinchroniniu cilindriniu varikliu. Programiniu paketu ,,Matlab“ yra sudaryti pavaros matematiniai modeliai α, β koordinačių sistemoje. Uždaviniai – tiesiaeigės iešmo elektros pavaros kompiuterinio modelio sudarymas, tyrimas ir dinaminių charakteristikų imitavimas. Literatūros analizės dalyje išnagrinėtos tiesiaeigės elektros pavaros, jų taikymo sritys bei valdymo būdai. Magistro darbo teorinėje dalyje pateikiamos tiesiaeigių elektros pavarų skaičiavimo ir valdymo metodikų analizės. Tiriamoji dalis apima iešmo elektros pavaros su tiesiaeigiu cilindriniu asinchroniniu varikliu matematinių modelių sudarymą ir dinaminių charakteristikų tyrimą programiniu paketu ,,Matlab“. Matematiniai modeliai yra sudaromi pavarai veikiant skirtingais darbo režimais (pavara perjungiama neapkrauta, pavara perjungiama apkrovus nominalia apkrova ir iešmą perjungiant pabaigoje ir pradžioje trukdant papildomai pasipriešinimo jėgai) ir tyrimo rezultatai pateikiami grafiškai. Gauti rezultatai yra palyginami ir apibendrinami. Išnagrinėjus teorinius tiesiaeigės iešmo elektros pavaros su asinchroniniu cilindriniu varikliu darbo režimų aspektus, pateikiamos išvados ir pasiūlymai. Tyrimo rezultatai gali būti panaudoti iešmo elektros pavaros su tiesiaeigiu asinchroniniu varikliu racionaliam ir optimaliam realizavimui geležinkelio transporto automatinio valdymo sistemose. Darbą sudaro 9 dalys: santrumpos ir simboliai, įvadas... [toliau žr. visą tekstą] / The final Bachelor thesis analyses point electric drive with cylinder-type linear asynchronous motor. Software package ,,Matlab“ was used to prepare mathematical models of the drive in α, β coordinate system. Objectives: preparing and analyzing a computer model of linear point electric drive, simulation of dynamic characteristics. The analysis of literary sources deals with linear electric drives, their application areas and methods of control. Theoretical part of the Master thesis presents analyses of calculation and control methods of linear electric drives. The analytical part of the thesis includes mathematical models of point electric drive with cylinder-type linear asynchronous motor and the analysis of dynamic characteristics using software package ,,Matlab“. Mathematical models were prepared when the drive operated in different modes (the drive switched without load, the drive switched with nominal load, the switch connected at the end or beginning, thereby blocking additional resistance force). Research results were presented in a graphical form. Obtained results were compared and summarized. Following the analysis of the theoretical aspects of operating modes of linear point electric drive with cylinder-type asynchronous motor, conclusions and recommendations were presented. Research results can be used for rational and optimal realization of point electric drive with linear asynchronous motor in automatic railway control systems. The thesis consists of nine parts:... [to full text]

Plant cell and tissue cultivations are of growing interest for the production of structurally complex and expensive plant-derived products, especially in pharmaceutical production. Problems with up-scaling, low yields and high-priced process conditions result in an increased demand for models to provide comprehension, simulation, and optimization of production processes. In the last 25 years, many models have evolved in plant biotechnology; the majority of them are specialized models for a few selected products or nutritional conditions. In this article we review, delineate, and discuss the concepts and characteristics of the most commonly used models. Therefore, the authors focus on models for plant suspension and submerged hairy root cultures. The article includes a short overview of modeling and mathematics and integrated parameters, as well as the application scope for each model. The review is meant to help researchers better understand and utilize the numerous models published for plant cultures, and to select the most suitable model for their purposes.