Universidad del Norte, Colombia

About: Universidad del Norte, Colombia is a education organization based out in Barranquilla, Colombia. It is known for research contribution in the topics: Population & Context (language use). The organization has 3562 authors who have published 4355 publications receiving 37861 citations. The organization is also known as: University of the North, Colombia & Uninorte.

STM study of large organic molecules adsorption on Si(100)-2 × 1

Abstract: The adsorption of large organic molecules, including tetracene and perylene, on clean Si(100) is followed by scanning tunnelling microscopy (STM) in an ultra high vacuum environment. Different adsorption sites have been observed for these organic molecules. Two types of tetracene adsorption are indicated by filled state images but three types can be distinguished in empty state images. Molecules aligned both along and perpendicular to the silicon dimer rows can be observed. Measurements of the length of this molecule in all configurations indicate that the molecule stays intact during the adsorption process. High resolution of STM images reveal that the perylene molecules bond to the substrate in a vertical orientation and forming packs of perylene aligned perpendicular to the silicon dimmer rows. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

High variability geographical obfuscation for location privacy

Abstract: In the last few years, the number of applications that use the location of the users in order to provide a more personalized service have been increasing, mainly due to easy access to low cost smartphones, geographical positioning systems and other factors, like social networking. The concern of protecting this information is also increasing due to the capabilities than an eventual attacker could have if the location information is obtained. Some protection techniques have been proposed in the literature; for example, location obfuscation which slightly alters the location to hide the real one. However, this technique could be filtered out with time series-based mechanisms. In this work, the Pinwheel obfuscation technique is proposed in order to reduce the possibility of EMA-based filtering based on high variability and asymmetry of the induced noise. The results show that the level of filtered noise is reduced from 35% in N-RAND and 30% in θ-Rand obfuscation techniques, to 15% in Pinwheel, with asymmetric scenarios, while preserving a long final average distance from the original path after a filtering attack.