Articles — Project / Lab Report

Machine learning project report. The project aimed at predicting air quality based on weather and its code is available at https://github.com/annisall/mlproject.

We will study some aspects of the damped driven pendulum. We will see that the trajectory of damped driven pendulum is unpredictable under certain ranges of parameters. Under some conditions, the trajectory behaves like random. A perturbation of initial condition will lead to different result. Several mathematical tools will be introduced in this study.

cryptografische systemen zijn gebaseerd op stellingen uit de getaltheorie. Versleuteling en ontsleutelingen van berichten vragen vaak intensief computerrekenwerk. Bij visuele cryptografie wordt het rekenwerk echter tot een minimum beperkt. Ook hoeft de ontwerper van deze geheimcodes bijna geen gebruik te maken van wiskundige stellingen en eigenschappen. De ontsleuteling van een boodschap kan zelfs gebeuren zonder digitale hulpmiddelen: schuif twee transparanten met onherkenbare afbeeldingen over elkaar en kijk doorheen deze transparanten naar de ontsleutelde boodschap. In dit verslag worden drie technieken voor visuele cryptografie toegellicht. Voor de eerste techniek is er wel wat wiskundige achtergrondkennis nodig. De tweede en derde techniek zijn vlot uitvoerbaar zonder deze achtergrond.

Math project.

Bacterial cells can have DNA damage due to transcriptional error, or through the effect of an antibiotic. The SOS response is a bacterial cell program for coping with DNA damage, in which the cell cycle is arrested, and DNA repair is induced. The repairs have high probability in leading to mutagenesis in the bacteria, which can lead to antibiotic resistance. The RecA protein in bacteria is responsible for the activation of the SOS response; therefore, making it a target for inhibition. I elected to use the ubiquitination system, natively used for apoptosis, as a means of targeted degradation of the RecA protein in bacteria prone to mutations. Polyubiquitination of misfolded proteins leads to the breaking down of the protein with the aid of proteasomes, which break down unnecessary proteins through a chemical reaction known as proteolysis. Using random forest-predictors, I determined a statistically high likelihood of ubiquitination of the RecA protein in MRSA, Tuberculosis, and other high risk bacterial infections. I hypothesized that I could foster ubiquitin-tagging on RecA by forcing the protein to misfold. Chaperones are proteins which interact with each other to prevent specific sets of proteins from misfolding. CHIP (C terminus of HSC70-Interacting Protein) is a biomolecule that inhibits interactions between the chaperones of RecA. Adding CHIP, ubiquitin, and 26s proteasomes into the bacterial system, should theoretically lead to the degradation of the RecA protein inside the bacteria. I tested my hypothesis by conducting an assay for monitoring CHIP-mediated ubiquitination, and conducted analysis on the assay using SDS- Page gel electrophoresis, and Western-blotting. The resulting data showed signs of polyubiquitination on the RecA protein, with chains of five or more ubiquitin, showing high drug potential. Adding an antibody drug conjugate, containing all the necessary components of a CHIP-mediated ubiquitination reaction, to common antibiotics can lead to the inhibition of bacterial mutagenesis, and higher antibiotic drug potency.

A dual energy radiography method using basis decomposition was developed, the process to do it is shown and it is compared against an alternate more direct method of analyzing the data using the logarithm of the original data, concluding that this second method does work but it is not better than basis decomposition.

The decreasing of groundwater quality has been the major issue in Tangerang area. One of the key process is the interaction between groundwater and Cisadane river water, which flows over volcanic deposits of Bojongmanik Fm, Genteng Fm, Tuf Banten, and Alluvial Fan. The objective of this study is to unravel such interactions based on the potentiometric mapping in the riverbank. We had 60 stop sites along the riverbank for groundwater and river water level observations, and chemical measurements (TDS, EC, temp, and pH). Three river water gauge were also analyzed to see the fluctuations. We identified three types of hydrodynamic relationships with fairly low flow gradients: effluent flow at Segmen I (Kranggan - Batuceper) with 0.2-0.25 gradient, perched flow at Segmen II (Batuceper-Kalibaru) with gradient 0.2-0.25, and influent flow at Segmen III (Kalibaru-Tanjungburung) with gradient 0.15-0.20. Such low flow gradient is controlled by the moderate to low morphological slope in the area. The gaining and losing stream model were also supported by the river water fluctuation data. TDS and EC readings increased more than 40% from upstream to downstream. At some points the both measurements were two times higher than the permissible limits, along with the drops of pH values at those areas. This study shows the very close interaction between Cisadane river water and groundwater in the riverbank. Therefore the authorities need to be managed the areas with a very strict regulations related to the small and large scale industries located near by the river.

The aim of the experiment is to study elliptically polarized light using a Fresnel rhomb and to determine the ratio of semi major axis to the semi minor axis of the various elliptically polarised light forms for different angles of plane polarised incidence at the rhomb

The viscosity of a particular fluid is an interesting parameter that plays an important role in fluid dynamics of that fluid. We chose the common household cooking item canola oil. Using a ball drop, we set out to measure viscosity at various temperatures and create a model for the viscosity of canola oil as a function of temperature, as well as an accurate measurement for viscosity at room temperature. It was found that the viscosity between 0 and 40 degrees Celsius can be approximated using an exponential function and that an estimation for viscosity at room temperature was not very difficult to obtain. The precision of this measurement was limited by uncertainty in lab equipment used to measure various quantities as well as the image analysis software we used and the limited frame-rate of our camera.