Development of the TanDEM-X Calibration Concept: Analysis of Systematic Errors

The TanDEM-X mission, result of the partnership between the German Aerospace Center (DLR) and Astrium GmbH, opens a new era in spaceborne radar remote sensing. The first bistatic satellite synthetic aperture radar mission is formed by flying the TanDEM-X and TerraSAR-X in a closely controlled helix formation. The primary mission goal is the derivation of a high-precision global digital elevation model (DEM) according to High-Resolution Terrain Information (HRTI) level 3 accuracy. The finite precision of the baseline knowledge and uncompensated radar instrument drifts introduce errors that may compromise the height accuracy requirements. By means of a DEM calibration, which uses absolute height references, and the information provided by adjacent interferogram overlaps, these height errors can be minimized. This paper summarizes the exhaustive studies of the nature of the residual-error sources that have been carried out during the development of the DEM calibration concept. Models for these errors are set up and simulations of the resulting DEM height error for different scenarios provide the basis for the development of a successful DEM calibration strategy for the TanDEM-X mission

User-defined Machine Learning Functions

[EN] In Data Science practices it is commonly assumed and accepted to abstract and slice big data architectures into functional layers, in particular a triad of governance-, data analysis- and persistence layer. However, moving input data to analysis, which is required when abstracting a data persistence layer from a data analysis layer, needs to be considered as highly expensive at large scale. Especially in Machine Learning (ML), the data analytics layer module requires intense data movements during preprocessing, data integration, preparation and analytics steps. Therefore, we propose to consider an application of User-defined functions (UDFs) with ML capabilities directly at the data persistence layer, i.e. at the database. We observed that it might be overall most efficient in traditional on-premise (i.e. non-cloud) RDBMS environments to apply ML UDFs if only singular and self-contained ML tasks should be integrated. Whereas the availability of ML functions in databases was predominantly owned by proprietary solutions in the past, there are now entirely new opportunities to integrate Python ML libraries with open source RDBMS. Whilst considering Python as one dominant language for ML applications in Data Science, the now achieved facilitation of Python ML UDFs consequently opens a broad range of opportunities to add Python ML capabilities to already existing persistence layers - without having to build an additional data analysis layer and related pipeline. With this presentation we deliver preliminary results of our industry research about database centric ML applications, and we open source code for the application of (un)supervised learning models.Herrmann, M.; Fiedler, M. (2020). User-defined Machine Learning Functions. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/149581OC

Der Markt für Öko-Eier in Deutschland

Einige Monate nach der Nitrofenkrise 2002 hat sich der Markt für Bio-Eier wieder stabilisiert. Doch gibt es immer noch jede Menge Herausforderungen für die Bio-Geflügelhalter. Diese reichen von der Umsetzung der 100-%igen Bio-Fütterung über die Züchtung von an die Bedürfnisse des Öko-Landbaus angepassten Hühnerrassen bis hin zu einem erfolgreichen Marketing im Kontext einer angespannten gesamtwirtschaftlichen Situation

SecMon: End-to-End Quality and Security Monitoring System

The Voice over Internet Protocol (VoIP) is becoming a more available and popular way of communicating for Internet users. This also applies to Peer-to-Peer (P2P) systems and merging these two have already proven to be successful (e.g. Skype). Even the existing standards of VoIP provide an assurance of security and Quality of Service (QoS), however, these features are usually optional and supported by limited number of implementations. As a result, the lack of mandatory and widely applicable QoS and security guaranties makes the contemporary VoIP systems vulnerable to attacks and network disturbances. In this paper we are facing these issues and propose the SecMon system, which simultaneously provides a lightweight security mechanism and improves quality parameters of the call. SecMon is intended specially for VoIP service over P2P networks and its main advantage is that it provides authentication, data integrity services, adaptive QoS and (D)DoS attack detection. Moreover, the SecMon approach represents a low-bandwidth consumption solution that is transparent to the users and possesses a self-organizing capability. The above-mentioned features are accomplished mainly by utilizing two information hiding techniques: digital audio watermarking and network steganography. These techniques are used to create covert channels that serve as transport channels for lightweight QoS measurement's results. Furthermore, these metrics are aggregated in a reputation system that enables best route path selection in the P2P network. The reputation system helps also to mitigate (D)DoS attacks, maximize performance and increase transmission efficiency in the network.Comment: Paper was presented at 7th international conference IBIZA 2008: On Computer Science - Research And Applications, Poland, Kazimierz Dolny 31.01-2.02 2008; 14 pages, 5 figure

09192 Abstracts Collection -- From Quality of Service to Quality of Experience

From 05.05. to 08.05.2009, the Dagstuhl Seminar 09192 ``From Quality of Service to Quality of Experience\u27\u27 was held in Schloss Dagstuhl~--~Leibniz Center for Informatics. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available

09192 Executive Summary -- From Quality of Service to Quality of Experience

From May 05 to May 08, 2009, the Dagstuhl Seminar 09192 ``From Quality of Service to Quality of Experience \u27\u27 was held in Schloss Dagstuhl~--~Leibniz Center for Informatics. The notion of emph{Quality of Service} has served as a central research topic in communication networks for more than a decade, however, usually starting from a rather technical view on service quality. Therefore, recently the notion of emph{Quality of Experience} has emerged, redirecting the focus towards the end user and trying to quantify her subjective experience gained from using a service. The goal of this Dagstuhl seminar is to discuss this important paradigm shift in an interdisciplinary international community of key researchers, to investigate innovative research methodologies and to deepen the scientific understanding of this topic which is highly relevant for the economic success of future mobile and fixed communication services

Socio-economic issues in future generation internet

Socio-Economic Issues in Future Generation Interne