Suomalainen yhdistys haavoitettujen ja sairaitten sotilasten hoitamista varten: Suomen Punainen Risti

Naantal

Failing Food Supply: Permaculture\u27s Potential

Conventional agriculture is the currently leading production method to grow crops in the western hemisphere. Long-term sustainability of the system and all the components is secondary to producing high yields each growing season, which leads to issues such as erosion and reduced soil quality. Other agricultural production methods such as permaculture aim to build soil and improve quality every growing season. This experiment intends to look at the potential of permaculture to improve soil quality on small-scales at the end of each growing season. The parameters to gauge success are a larger concentration of macronutrients at the end of the growing season and a pH within the ideal 6.0-7.0 range. Replication of two experimental and control plots were implemented to test the potential of permaculture on small-scales, with control plot plants separated into rows to mimic conventional agriculture and experimental plot plants in the permaculture beds were placed by each other to enhance plant connections. Each bed received two applications of either organic or conventional fertilizer on the same date. Statistical analysis of the data showed that the only macronutrient successfully impacted by the permaculture methods was sulfur. The pH for both treatments was not improved and increased well above the ideal 6.0 – 7.0 range

Performance of Concrete with Different Cement Finenesses and Nano-activators

The excessive shrinkage in modern concrete is the result of the construction industry in its quest to complete the job as soon as possible. In order to accomplish this, the fineness of cement was increased significantly in recent decades for a faster rate of strength gain. To combat the cement fineness and reverse the trend of shrinkage, the usage of coarse cements and nanoparticles should be strongly considered. The coarse cement is used to reduce the shrinkage of concrete, while the nanoparticle increases the early strength, alleviating the original concerns of reduced early strength when using coarse cement. Work in this study provides enough evidence toward coarse cement and nanoparticle use being extremely beneficial to concrete. In particular, the coarse cement reduces the shrinkage, while the incorporation of nanoparticles not only improves the initial strength gain, but also further decreases the shrinkage. At the age of seven days, the mixtures using coarse cement with nanoparticles show a compressive strength greater than the Type I/II mixtures used as reference. Regarding shrinkage, the use of nanoparticles in mixtures with coarse cement outperformed the coarse cement by itself. Thus, the use of nanoparticles as an activator in coarse cement concrete is considered a viable option for applications where low shrinkage and long-term durability are desirable. Advisor: Jiong H

Exploited or Engaged? Dark Game Design Patterns in Clicker Heroes, FarmVille 2, and World of Warcraft

publishedVersio

Finding shared RSA factors in the Certificate Transparency logs

When generating RSA keys, proper random generators are crucial. If the generators are not truly random, keys may be generated with the same factors, making them vulnerable to compromise. Doing a simple greatest common divisor computation would reveal the secret factors. We collected over 159 million unique RSA public keys from the Certificate Transparency logs, which is, to our knowledge, the largest set used for such an analysis so far. Our goal was to check if any of these keys shared factors, thus allowing us to compute the private keys easily. To do this, we implemented a batch greatest common divisor algorithm used for this purpose in previous studies. Our result from checking the 159 million RSA keys was that we factored eight keys, all of which were issued by the same certificate authority. We then gathered more than 700,000 keys from that particular certificate authority, of which we were able to factor 355 keys. We reached out to the issuer of the broken certificates, and they launched an investigation into our findings. Their investigation concluded that all broken keys were generated by a single user who they claim had abused their system.Masteroppgave i informatikkINF399MAMN-PROGMAMN-IN

Projective 3D-reconstruction of Uncalibrated Endoscopic Images

The most common medical diagnostic method for urinary bladder cancer is cystoscopy. This inspection of the bladder is performed by a rigid endoscope, which is usually guided close to the bladder wall. This causes a very limited field of view; difficulty of navigation is aggravated by the usage of angled endoscopes. These factors cause difficulties in orientation and visual control. To overcome this problem, the paper presents a method for extracting 3D information from uncalibrated endoscopic image sequences and for reconstructing the scene content. The method uses the SURF-algorithm to extract features from the images and relates the images by advanced matching. To stabilize the matching, the epipolar geometry is extracted for each image pair using a modified RANSAC-algorithm. Afterwards these matched point pairs are used to generate point triplets over three images and to describe the trifocal geometry. The 3D scene points are determined by applying triangulation to the matched image points. Thus, these points are used to generate a projective 3D reconstruction of the scene, and provide the first step for further metric reconstructions

Introduction: Playful Transgressions

Research Council of NorwaypublishedVersio

Intrusive media and knowledge work: how knowledge workers negotiate digital media norms in the pursuit of focused work

This article analyses how knowledge workers experience and reflect upon intrusions from digital media in the pursuit of focused work. As a multitude of digital media technologies have become integral to working life, scholars have observed a connectivity paradox in which these technologies are experienced as both helpful and hindering, as integral to but also intruding upon focus and concentration. To understand this important and widespread ambivalence in digital society, we analyze qualitative interviews with knowledge workers in a range of professions. With a theoretical framework drawing on domestication theory, sociology of work and critiques of digital modernity, we highlight how workers negotiate spatial, temporal, and technological conditions, and the conflicted norms that are activated in the process. Our findings indicate that negotiations about digital media technologies come to represent psychological, cultural and social dilemmas that go beyond the individual worker, but are nevertheless experienced as individual cross-pressures to be managed.publishedVersio

Abrasive Waterjet Turning of High Performance Materials

AbstractThe cutting of high performance materials requires specific machine tools and cutting tools. The wear resistance of cutting tools is important for turning of hypereutectic aluminium silicon or titanium aluminide alloys. Abrasive waterjet turning has been shown to be a suitable cutting process for these challenging materials. The tool life time of at least 10hours combined with a material removal rate of up to 0.8cm3/min and low process temperatures give this cutting technology a very high potential. Furthermore the material close to the cutting surface is less modified compared to conventional rough turning. The same effects are of particular interest with regard to the functional capability of waterjet turned γ-TiAl-alloys