University of Mannheim

About: University of Mannheim is a education organization based out in Mannheim, Germany. It is known for research contribution in the topics: Context (language use) & Politics. The organization has 4448 authors who have published 12918 publications receiving 446557 citations. The organization is also known as: Uni Mannheim & UMA.

Local-lag and timewarp: providing consistency for replicated continuous applications

Abstract: In this paper, we investigate how consistency can be established for replicated applications changing their state in reaction to user-initiated operations as well as the passing of time. Typical examples of these applications are networked computer games and distributed virtual environments. We give a formal definition of the terms consistency and correctness for this application class. Based on these definitions, it is shown that an important tradeoff relationship exists between the responsiveness of the application and the appearance of short-term inconsistencies. We propose to exploit the knowledge of this tradeoff by voluntarily decreasing the responsiveness of the application in order to eliminate short-term inconsistencies. This concept is called local-lag. Furthermore, a timewarp scheme is presented that complements local-lag by guaranteeing consistency and correctness for replicated continuous applications. The computational complexity of the timewarp algorithm is determined in theory and practice by examining a simple networked computer game. The timewarp scheme is then compared to the well-known dead-reckoning approach. It is shown that the choice between both schemes is application-dependent.

The Role of Non-Financial Factors in Internal Credit Ratings

Abstract: Internal credit ratings are expected to gain in importance because of their potential use for determining regulatory capital adequacy and banks' increasing focus on the risk-return profile in commercial lending. Whereas the eligibility of financial factors as inputs for internal credit ratings is widely accepted, the role of non-financial factors remains ambiguous. Analyzing credit file data from four major German banks, we find evidence that the combined use of financial and non-financial factors leads to a more accurate prediction of future default events than the single use of each of these factors.

Learning more about the underground economy: a case-study of keyloggers and dropzones

Abstract: We study an active underground economy that trades stolen digital credentials In particular, we investigate keylogger-based stealing of credentials via dropzones, anonymous collection points of illicitly collected data Based on the collected data from more than 70 dropzones, we present an empirical study of this phenomenon, giving many first-hand details about the attacks that were observed during a seven-month period between April and October 2008 We found more than 33 GB of keylogger data, containing stolen information from more than 173,000 victims Analyzing this data set helps us better understand the attacker's motivation and the nature and size of these emerging underground marketplaces