Konrad Jünemann

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The distributed hash table (DHT) formed by BitTorrent has become very popular as a basis for various kinds of services. Services based on this DHT often assume certain characteristics of the DHT. For instance, for realizing a decentralized bootstrapping service a minimum number of peers running on a certain port are required. However, key characteristics(More)
Distributed Hash Tables (DHTs) prove valuable for distributed architectures by providing distributed information lookup, routing, and data storage while promising good scalability and robustness at the same time. From this point of view, a DHT could be seen as a basic service that can be used to build distributed applications. Whereas today no widely(More)
Outsourcing data to external providers has gained momentum with the advent of cloud computing. Encryption allows data confidentiality to be preserved when outsourcing data to untrusted external providers that may be compromised by attackers. However, encryption has to be applied in a way that still allows the external provider to evaluate queries received(More)
The information quality of email exchanges is often low, and -- as mobile devices are more and more often used for communication -- it becomes increasingly important to try to improve the quality by providing additional information, related to email contents. The field of information extraction (IE) provides relevant tools to recognize objects that could(More)
For cloud-based outsourcing of confidential data, various techniques based on cryptography or data-fragmentation have been proposed, each with its own tradeoff between confidentiality, performance, and the set of supported queries. However, it is complex and error-prone to select appropriate techniques to individual scenarios manually. In this paper, we(More)
The benefits of distributing a network simulation depend on characteristics of the simulated network. Performance improvements reported in the literature are comparatively low for peer-to-peer overlay networks in particular, as the logical topology of these networks can necessitate frequent synchronization between the processors executing the simulation. In(More)
Distributed Hash Tables (DHTs) provide information lookup within a Peer-to-Peer (P2P) network. A multitude of distributed applications leverages DHTs for offering more advanced services such as distributed file systems, web caches or distributed DNS. For such DHT-based applications, lookup performance is highly important. However, lookup performance is(More)
For credibility of simulation results, reproducibility of simulation runs is a must. However, reproducibility requires a thorough management of all data involved in the simulation process. The corresponding management of data can be error-prone and time consuming if performed manually. In this paper we introduce a simulation management approach that ensures(More)