105 citations · 231 across the 11 of their papers we have counts for
11 papers
Robust and Scalable Content-and-Structure Indexing (Extended Version)
Kevin Wellenzohn, Michael H. Böhlen, Sven Helmer +2
Frequent queries on semi-structured hierarchical data are Content-and-Structure (CAS) queries that filter data items based on their location in the hierarchical structure and their…
Dynamic Spanning Trees for Connectivity Queries on Fully-dynamic Undirected Graphs (Extended version)
Qing Chen, Oded Lachish, Sven Helmer +1
Answering connectivity queries is fundamental to fully dynamic graphs where edges and vertices are inserted and deleted frequently. Existing work proposes data structures and algor…
Structural Textile Pattern Recognition and Processing Based on Hypergraphs
Vuong M. Ngo, Sven Helmer, Nhien-An Le-Khac +1
The humanities, like many other areas of society, are currently undergoing major changes in the wake of digital transformation. However, in order to make collection of digitised ma…
Cache-Efficient Sweeping-Based Interval Joins for Extended Allen Relation Predicates (Extended Version)
Danila Piatov, Sven Helmer, Anton Dignös +1
We develop a family of efficient plane-sweeping interval join algorithms that can evaluate a wide range of interval predicates such as Allen's relationships and parameterized relat…
Dynamic Interleaving of Content and Structure for Robust Indexing of Semi-Structured Hierarchical Data (Extended Version)
Kevin Wellenzohn, Michael H. Böhlen, Sven Helmer
We propose a robust index for semi-structured hierarchical data that supports content-and-structure (CAS) queries specified by path and value predicates. At the heart of our approa…
A Similarity Measure for Weaving Patterns in Textiles
Sven Helmer, Vuong M. Ngo
We propose a novel approach for measuring the similarity between weaving patterns that can provide similarity-based search functionality for textile archives. We represent textile…
A survey study on major technical barriers affecting the decision to adopt cloud services
Nattakarn Phaphoom, Xiaofeng Wang, Sarah Samuel +2
In the context of cloud computing, risks associated with underlying technologies, risks involving service models and outsourcing, and enterprise readiness have been recognized as p…
Affordable and Energy-Efficient Cloud Computing Clusters: The Bolzano Raspberry Pi Cloud Cluster Experiment
Pekka Abrahamsson, Sven Helmer, Nattakarn Phaphoom +8
We present our ongoing work building a Raspberry Pi cluster consisting of 300 nodes. The unique characteristics of this single board computer pose several challenges, but also offe…
Solving Orienteering with Category Constraints Using Prioritized Search
Paolo Bolzoni, Sven Helmer
We develop an approach for solving rooted orienteering problems with category constraints as found in tourist trip planning and logistics. It is based on expanding partial solution…
Bringing the Cloud to Rural and Remote Areas - Cloudlet by Cloudlet
Pekka Abrahamsson, Sven Helmer, Tosin Daniel Oyetoyan +9
Instead of relying on huge and expensive data centers for rolling out cloud-based services to rural and remote areas, we propose a hardware platform based on small single-board com…
Ordering Selection Operators Using the Minmax Regret Rule
Khaled H. Alyoubi, Sven Helmer, Peter T. Wood
Optimising queries in real-world situations under imperfect conditions is still a problem that has not been fully solved. We consider finding the optimal order in which to execute…