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Data schemas of noSQL stores for the storage of sensor data
No full textIn this thesis we are concerned with the storage of sensor data. Sensor data can also be characterized as time series data. The exponential increase of sensor data exposes the scalability issues of relational databases. noSQL databases are a new type of data stores, which are built with scalability and availability in mind. The capabilities provided by these databases, makes them a good candidate for the storage of time series data.
The purpose of this thesis is to compare different data schemas for noSQL databases and their applicability for the storage of sensor data. An overview of noSQL database taxonomies is presented. Also, various data schemas used by experts in production are researched and presented. This gives an insight on which data schemas are appropriate for the storage of time series.
Next, we perform load tests using Cassandra, which is a noSQL database suitable for the storage of sensor data. The tests are performed with regard to performance of different data schemas for the storage of sensor data. A test structure and scennarios are defined and different data schemas are tested on the basis of throughput and latency. The results are expected to provide suggestions for the suitable noSQL data schemas to use in different situations when storing time series data.
A candidate therapeutic vaccine against hepatitis C virus infection : use of a recombinant alphavirus vector
No full textPeng Peng Ip beschrijft in dit proefschrift haar onderzoek naar de ontwikkeling van een immuuntherapie gericht tegen hepatitis C virus infecties.
Wereldwijd zijn ongeveer 150 miljoen mensen chronisch besmet met hepatitis C virus (HCV) en jaarlijks sterven 350.000 mensen aan een HCV-gerelateerde leverziekte zoals cirrose of leverkanker. In Nederland zijn ongeveer 60.000 mensen besmet met HCV, vaak nog zonder het te weten.
Het doel van het promotie onderzoek was om een vaccin tegen HCV infectie te ontwikkelen. De basis van het vaccin is afgeleid van een knaagdiervirus, het Semliki Forest virus (SFV). SFV kan zodanig veranderd worden dat het eiwitten naar keuze gaat produceren. Een cel die geïnfecteerd wordt met zo’n recombinant virusdeeltje zal een grote hoeveelheid van dit eiwit aanmaken en vervolgens afsterven. Deze afstervende cel wordt daarna opgenomen door antigeen-presenterende cellen die het eiwit presenteren aan andere cellen van het immuunsysteem. Het immuunsysteem maakt daarop afweercellen die HCV-geïnfecteerde cellen kunnen herkennen en doden, zogenaamde cytotoxische T cellen (CTL).
De SFV vaccins die ontworpen zijn wekken een sterke afweer op. Verder is een nieuwe methode ontwikkeld om de rSFV vaccins verder te verbeteren waardoor een nog sterkere afweer opgewekt wordt. Tot slot laten we zien dat de keuze van het antigeen wat ingebouwd moet worden in een vaccin voorspeld kan worden door mathematische algoritmen.
De ontwikkeling van een HCV vaccin voor het behandelen van HCV patiënten is van groot belang, de kennis verkregen en beschreven in dit proefschrift brengt dit weer een kleine stap dichterbij.
Hepatitis C virus (HCV) is a human tumor-associated virus that is transmitted by blood and infects the human liver. The majority of HCV-infected patients (> 70%) does not clear the infection naturally and develops chronic hepatitis, which is associated with the development of liver cirrhosis, liver failure and hepatocellular carcinoma. In patients with a chronic HCV infection a poor and narrow-spectrum cellular immune response against HCV is often observed while in patients who recovered from acute infection the immune responses are broader. Thus, boosting the host’s immune response would be a fundamental therapeutic strategy to eradicate the persisting viruses and halt associated liver diseases.
In this thesis, we studied the development of HCV therapeutic vaccines including (i) generation of HCV vaccines based on a potent viral vector, Semliki Forest virus (SFV), (ii) enhancing the vaccine efficacy the SFV vector and (iii) selection of antigens for a precise vaccine design. We generated three HCV vaccines expressing all or parts of the HCV nonstructural proteins (nsPs) and demonstrated that vaccination with these SFV-based HCV vaccines induced a robust cellular immune response against one nsP. Next, in order to induce strong response against other nsPs, we generated SFV-based vaccines with the inclusion of a carrier protein. We showed that the carrier protein efficiently enhanced the efficacy of the SFV-based vaccines. Last, we identified antigen candidates for vaccine design by using multiple prediction algorithms. Taken together, studies described in this thesis provide a fundamental understanding on the design of highly potent therapeutic HCV vaccines.
Elastic anomalies associated with structural and magnetic phase transitions in single crystal hexagonal YMnO3
No full textResonant ultrasound spectroscopy has been used to measure the elastic and anelastic behaviour through known structural and magnetic phase transitions in single crystal hexagonal YMnO3. Anomalous elastic behaviour is observed at the high temperature structural transition at ~1260 K, with a discontinuity in the elastic constants and nonlinear recovery below Tc, consistent with λeQs^2 coupling. There is no change in dissipation associated with this high temperature transition, and no evidence in the elastic or anelastic behaviour for any secondary transition at ~920 K, thus supporting the thesis of a single high temperature transformation. Elastic stiffening is observed on cooling through TN, in accordance with previous studies, and the excess elastic constant appears to scale with the square of the magnetic order parameter. The strains incurred at TN are a factor of ~20 smaller than those at the structural transition, implying very weak λeQm^2 coupling and a dominant contribution to the variation in the elastic constants from λe2Qm^2. The increased acoustic dissipation above TN is consistent with an order–disorder process.
From Radio Pulse to Elusive Particle
No full textKosmische deeltjes zijn mysterieuze en zeer energetische deeltjes uit de ruimte. Men kan nog veel leren over deze ongrijpbare deeltjes. Wanneer een deeltje de atmosfeer van de aarde raakt worden er miljoenen tot miljarden nieuwe deeltjes gecreëerd: een deeltjesregen. Deze deeltjesregen beweegt zich naar het aardoppervlak waar de detectoren van het Pierre Auger Observatorium het registreert. Het observatorium bestaat 1600 detectoren die verspreid staan over een gebied zo groot als Friesland.
Sinds enige jaren heeft het Pierre Auger Observatorium een extra techniek ontwikkeld om kosmische deeltjes met behulp van radioantennes te meten. De antennes meten radiopulsen die door de deeltjesregens ontstaan.
Dit werk richt zich op de detectie-technieken en het oplossen van technische problemen bij het detecteren van deze pulsen. Detectie is niet makkelijk omdat de pulsen van zeer korte duur zijn en nauwelijks boven de galactische achtergrondruis uitkomen. Het probleem word nog lastiger gemaakt door menselijke stoorzenders. Een nieuwe methode, gebaseerd op lineaire predictie, is ontwikkeld om deze stoorzenders weg te filteren. Het blijkt dat deze methode met name geschikt is bij directe detectie in de geïntegreerde software van de radio detectoren.
Verder zijn twee verschillende fysische processen die voor het ontstaan van deze radio pulsen zorgen geïdentificeerd en ontrafeld door een vergelijking te maken van de eerste metingen met zes verschillende software simulaties. Dit breng ons dichter bij het begrijpen van de radio emissies van kosmische deeltjesregens.
Cosmic rays are mysterious and very energetic particles from space. There is much to be learnt about the origin an nature of these elusive particles. When a cosmic ray hits the earth's atmosphere this creates a cascade of millions to billions of secondary particles: an air shower. This air shower travels towards the earth's surface and is detected the Pierre Auger Observatory in Argentina. This observatory consists of a 1600 particle detectors which are spread out over an area as large as Washington.
Recently, the Pierre Auger Collaboration has developed an additional technique to measure cosmic rays by using radio antennas. The antennas measure radio pulses which are created by these air showers.
The work focuses on the detection techniques and tackles some technical problems involving the detection of these pulses. Detection is difficult because the pulses are very short-lived and barely register above the galactic background noise. The situation is exacerbated by the effects of human made radio interference. A novel method based on linear prediction is developed to filter out (some of) the human made background noise. It turns out that the method based on linear prediction is especially useful for applications in real-time data taking in the embedded software of the radio detectors.
Additionally, two physical processes involved in the creation of these pulses are identified and disentangled by comparing the first measurements with simulations from six different software packages. This brings us closer to a deeper understanding of the physics of radio emissions from cosmic-ray-induced air-showers.
On the calculation of safety stocks
No full textIn forecasting and inventory control textbooks and software applications, the variance of the cumulative lead-time forecast error is, almost invariably, taken as the sum of the error variances of the individual forecast intervals. For stationary demand and a constant lead time, this implies multiplying the single period variance (or Mean Squared Error) by the lead-time. This standard approach is shown in this paper to always underestimate the true lead-time demand variability, resulting in too low safety stocks and poor service. For two of the most widely applied forecasting techniques (Single Exponential Smoothing and Simple Moving Average) we present corrected expressions and show that the error in the standard approach is often considerable. The same fundamental problem exists for all forecasting techniques and all demand processes, and so this issue deserves wider recognition and offers ample opportunities for further research.
Application of metal triflate catalysts for the trans-esterification of Jatropha curcas L. oil with methanol and higher alcohols
No full textThis paper describes an experimental study on the application of metal triflate salts for the (trans-) esterification of fatty esters (triolein, methyl oleate, methyl linoleate), fatty acid (oleic acid), as well as Jatropha curcas L. oil with methanol and higher alcohols (ethanol, n-propanol, iso-propanol, iso-butanol, tert-butanol). The effect of the metal type (scandium, bismuth, aluminium, lanthanum, copper, zinc) and process conditions on reaction performance were evaluated. Highest conversions were obtained with Al(OTf)3. Reaction of triolein with methanol gave 99 mol% conversion at 165 °C for 1 h and the main product was the methyl ester. In addition, partial methoxylation of the carbon–carbon double bonds in the fatty acid chains was observed, though their fraction in the mixture was less than 20 mol%. The trans-esterification reaction was also successfully performed using higher alcohols, giving >95 % conversions for ethanol, n-propanol, iso-propanol and iso-butanol, whereas tert-butanol was not reactive. For the reaction of oleic acid with methanol, quantitative esterification, partial methoxylation of the carbon–carbon double bonds and the formation of small amounts of a lactone was observed. The methodology using Al(OTf)3 was successfully performed on the trans-esterification reaction of JO (FFA content of 2.1 wt%) with various alcohols. Key properties (viscosity, pour point and cloud points) of the (branched) Jatropha esters were determined. The best cold-flow properties were obtained for the iso-propyl esters of JO, with cloud point and pour point of -3 and -24 °C, respectively.
Expression differences in lipid metabolism genes with high-fat diet, calorie restriction, and exercise in livers of mice
No full textDe begeleider en/of auteur heeft geen toestemming gegeven tot het openbaar maken van de scriptie.
The supervisor and/or the author did not authorize public publication of the thesis.
Processing lignocellulosic biomass to biofuels: an overview
No full textAll around the world the energy demand is rising and the availability of fuels is decreasing, thus a solution must be found, which is also environmentally friendly. Lignocellulosic biomass is a potential answer to the problem described above, it contains a lot of energy in the form of sugars, and the methods to process this material, to for example ethanol, are available. In addition, lignocellulosic biomass is the most abundant renewable resource in the world. It is regarded as a promising starting material for biofuel production, because it is inexpensive, renewable and has favorable environmental properties. However, it must be cost effective and have the highest yield for industrial applications. This thesis highlights the obstacles to overcome; methods that could be used to process lignocellulose and suggests what processes could be used best.
On the theory of collisional orbits in the two center problem.
No full textThe two center problem or Euler's three body problem, concerns motion of a mass around two fixed centers of attraction. In this paper, we will specifically look at one-parameter families of non-collisional orbits in the planar case of the two center problem. The system is integrable and hence, by the Liouville-Arnold theorem, the phase space is foliated by invariant 2-tori. To find these 2-tori we make use of elliptic coordinates. Orbits lying on a 2-torus and are either periodic or quasi-periodic. Quasi-periodic orbits will densely fill the torus, so no one-parameter families of non-collisional orbits exist. We will show that in the case of periodic orbits, there can be at most two distinct collisional orbits and there exist one-parameter families of non-collisional orbits.
