150 research outputs found
Glocalization and Religious Communication in the Roman Empire: Two Case Studies to Reconsider the Local and the Global in Religious Material Culture
No full textOver the period in which the ancient Roman empire grew to its greatest extent, religion in the provinces underwent change. In this article, the author argues that glocalization as an explicit modern conceptual framework has added value to the analysis of religious material culture. First, the glocalization model is discussed in the context of a wider debate on the biased concept of Romanization. Second, a rationale is presented for interpreting Roman religious change with a glocalization perspective. Third, two concrete bodies of archaeological source material are re-interpreted within the glocalization framework: first the little studied rural sanctuary of Dhronecken near ancient Trier and second a particular form of religious gifts that appeared on an empire-wide scale as a ritual with respect to the salus, the well-being of the emperor. Based on the application of the glocalization framework to these sources, the author concludes that religious material culture in these cases can be seen as a process in which new forms of religious communication were created out of an interrelated and ongoing process of local and global cultural expressions
New Product Development Portfolios: Identifying the antecedents and consequences of decision-making processes
No full textProduct Innovatie ManagementIndustrial Design Engineerin
PRIDE: A Privacy-Preserving Decentralised Key Management System
No full textThere is an increase in interest and necessity for an interoperable and efficient railway network across Europe, creating a key distribution problem between train and trackside entities’ key management centres (KMC). Train and trackside entities establish a secure session using symmetric keys (KMAC) loaded beforehand by their respective KMC using procedures that are not scalable and prone to operational mistakes. A single system would simplify the KMAC distribution between KMCs; nevertheless, it is difficult to place the responsibility for such a system for the whole European area within one central organization. A single system could also expose relationships between KMCs, revealing information, such as plans to use an alternative route or serve a new region, jeopardizing competitive advantage. This paper proposes a scalable and decentralised key management system that allows KMC to share cryptographic keys using transactions while keeping relationships anonymous. Using non-interactive proofs of knowledge and assigning each entity a private and public key, private key owners can issue valid transactions while all system actors can validate them. Our performance analysis shows that the proposed system is scalable when a proof of concept is implemented with settings close to the expected railway landscape in 2030.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Cyber Securit
Estimating the impact of single and multiple freezes on video quality
No full textThis paper studies the impact of freezing of video on quality as experienced by users. Two types of freezes are investigated. First a freeze where the image pauses, so no frames were lost (frame halt). In the second type of freeze, the image freezes and skips that part of the video (frame drop). Measuring Mean Opinion Score (MOS) was done by subjective tests. Video sequences of 20 seconds were displayed for four types of content, to a total of 23 test subjects. We conclude there is no difference in the perceived quality between frame drops and frame halts. Therefore one model for single freezes was constructed. According to this model the acceptable freezing time (MOS>3.5) is 0.36 seconds. Pastrana – Vidal et al. (2004) suggested a relations ip between the probability of detection and the duration of the dropped frames. They also found that it is important to consider not only the duration of the freeze but also the number of freeze occurrences. Using their relationship between the total duration of the freeze and the number of occurrences, we propose a model for multiple freezes, based upon our model for single freeze occurrences. A subjective test was designed to evaluate the performance of the model for multiple freezes. Good performance was found on this data i.e a correlation higher than 0.9.TelecommunicationsElectrical Engineering, Mathematics and Computer Scienc
Efficient Crawling of Community Structures in Online Social Networks
No full textOnline social networks showed an enormous growth in the last decade. With the rise of online social networks such as Twitter and Facebook, researchers got the opportunity to access the data of social behavior of millions of people, whereas in the past it was limited to hundreds of people. For these researchers and marketeers it is of great interest to find communities within these large networks, as this is one of the opportunities to see how people behave in groups on a large scale. The most common approach of analyzing community structures in online social networks is to gather the network by downloading the user profiles one by one (crawling) and afterwards partition the network into groups or communities by community detection algorithms. However, crawling an entire social network is very time consuming and analyzing the networks with community detection algorithms can be computationally expensive. To overcome these problems, in this thesis a method is proposed for crawling nodes using the community structure of a network. It enables the researcher to start the analysis before completing the crawl. This new method performs between 66% and 480% better than existing crawling techniques such as Breadth First Search (BFS) and Depth First Search (DFS), because a smaller portion of the networks has to be crawled in order to crawl entire communities. The computer-generated networks used in this thesis were created using a new network generator which uniquely combines three features; it creates networks with explicit community structure, arbitrary degree distributions and adaptable community strength.TelecommunicationsElectrical EngineeringElectrical Engineering, Mathematics and Computer Scienc
Spatial distribution of wave overtopping
No full textThe goal of this master thesis is to describe the spatial distribution of the wave overtopping discharge over and behind the crest of a coastal defence structure. The influence of the most relevant parameters on this process is explored. This research has been performed by means of a physical model. The following relevant parameters were varied during the experiments to consider their influence on the spatial distribution of the wave overtopping discharge: wave height, wave steepness, water depth, crest height and wave spectrum. Four different types of wave overtopping discharges were measured in this research: total wave overtopping discharge, wave overtopping discharge directly behind the crest, wave overtopping discharge over impermeable backfill and wave overtopping discharge over permeable backfill. Based on the equality of the comparison between the experiment results and existing theoretical methods to calculate the total wave overtopping; further experiment results are considered as acceptable and reliable and can be used to derive the relation for the spatial distribution of the wave overtopping discharge. The total overtopping discharge flows over the crest of the breakwater and is divided in two components: the infiltrated discharge into the crest and the overtopping discharge directly behind the crest. A method to describe this distribution is defined. This method includes the influence of the wave height, wave length and crest height. The spatial distribution of the wave overtopping discharge behind the crest depends on the permeability of the backfill. For an impermeable backfill with a slope of 3% towards the breakwater, the overtopping discharge at every point behind the breakwater is divided in two parts: one part flows back over the impermeable backfill under the influence of gravity and the other part passes the point and travels further away from the breakwater. The final relation between the reduction factor (ratio between the overtopping discharge at a certain distance behind the crest and the overtopping discharge directly behind the crest) and the distance behind the crest was found to depend on a dimensionless presentation of the wave energy flux. For a permeable backfill, the overtopping discharge at every point behind the breakwater is divided in two parts: one part infiltrates into the backfill and the other part passes the point and travels further away from the breakwater. The influence of the wave energy flux on the relation between the reduction factor and the distance behind the crest was found to be smaller than for an impermeable backfill.Hydraulic EngineeringCivil Engineering and Geoscience
Dynamische verweking
No full textIn deze thesis komt het onderwerp dynamische verweking aan bod, er wordt onderzoek gedaan naar het verschijnsel, waarbij is vastgehouden aan de volgende hoofdvraag: “hoe zit het verschijnsel dynamische verweking precies in elkaar, welke parameters hebben invloed op het verschijnsel, wanneer treedt het fenomeen op en hoe is dit te voorspellen?” deze hoofdvraag zal in deze thesis worden ontleed om zo stap voor stap antwoord te geven en het verschijnsel te kunnen verklaren.Civil EngineeringGeo-EngineeringCivil Engineering and Geoscience
SImulatie MOdellen voor de NAtte waterstaat: Technical documentation WAQUA : version 1.0
No full text- …
