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Displaying 1-50 out of 68 total
Processing Reporting Function Views in a Data Warehouse Environment
Found in: Data Engineering, International Conference on
By Wolfgang Lehner, Wolfgang Hümmer, Lutz Schlesinger
Issue Date:March 2002
pp. 0176
Reporting functions reflect a novel technique to formulate sequence-oriented queries in SQL. They extend the classical way of grouping and applying aggregation functions by additionally providing a column-based ordering, partitioning, and windowing mechani...
 
fAST Refresh using Mass Query Optimization
Found in: Data Engineering, International Conference on
By Wolfgang Lehner, Bobbie Cochrane, Hamid Pirahesh, Markos Zaharioudakis
Issue Date:April 2001
pp. 0391
Abstract: Automatic Summary Tables (ASTs), more commonly known as materialized views, are widely used to enhance query performance, particularly for aggregate queries. Such queries access a huge number of rows to retrieve aggregated summary data while perf...
 
Forecasting the data cube: A model configuration advisor for multi-dimensional data sets
Found in: 2013 IEEE International Conference on Data Engineering (ICDE 2013)
By Ulrike Fischer,Christopher Schildt,Claudio Hartmann,Wolfgang Lehner
Issue Date:April 2013
pp. 853-864
Forecasting time series data is crucial in a number of domains such as supply chain management and display advertisement. In these areas, the time series data to forecast is typically organized along multiple dimensions leading to a high number of time ser...
 
SAP HANA distributed in-memory database system: Transaction, session, and metadata management
Found in: 2013 IEEE International Conference on Data Engineering (ICDE 2013)
By Juchang Lee,Yong Sik Kwon,Franz Farber,Michael Muehle,Chulwon Lee,Christian Bensberg,Joo Yeon Lee,Arthur H. Lee,Wolfgang Lehner
Issue Date:April 2013
pp. 1165-1173
One of the core principles of the SAP HANA database system is the comprehensive support of distributed query facility. Supporting scale-out scenarios was one of the major design principles of the system from the very beginning. Within this paper, we first ...
 
Adaptive Index Buffer
Found in: 2012 IEEE International Conference on Data Engineering Workshops (ICDEW)
By Hannes Voigt,Tobias Jaekel,Thomas Kissinger,Wolfgang Lehner
Issue Date:April 2012
pp. 308-314
With rapidly increasing datasets and more dynamic workloads, adaptive partial indexing becomes an important way to keep indexing efficiently. During times of changing workloads, the query performance suffers from inefficient tables scans while the index tu...
 
SMIX Live -- A Self-Managing Index Infrastructure for Dynamic Workloads
Found in: Data Engineering, International Conference on
By Thomas Kissinger,Hannes Voigt,Wolfgang Lehner
Issue Date:April 2012
pp. 1225-1228
As databases accumulate growing amounts of data at an increasing rate, adaptive indexing becomes more and more important. At the same time, applications and their use get more agile and flexible, resulting in less steady and less predictable workload chara...
 
F2DB: The Flash-Forward Database System
Found in: Data Engineering, International Conference on
By Ulrike Fischer,Frank Rosenthal,Wolfgang Lehner
Issue Date:April 2012
pp. 1245-1248
Forecasts are important to decision-making and risk assessment in many domains. Since current database systems do not provide integrated support for forecasting, it is usually done outside the database system by specially trained experts using forecast mod...
 
Private Table Database Virtualization for DBaaS
Found in: Utility and Cloud Computing, IEEE Internatonal Conference on
By Tim Kiefer,Wolfgang Lehner
Issue Date:December 2011
pp. 328-329
Growing number of applications store data in relational databases. Moving database applications to the cloud faces challenges related to flexible and scalable management of data. The obvious strategy of hosting legacy database management systems (DMBSs) on...
 
Evolving Ensemble-Clustering to a Feedback-Driven Process
Found in: Data Mining Workshops, International Conference on
By Martin Hahmann, Dirk Habich, Wolfgang Lehner
Issue Date:December 2010
pp. 401-408
Data clustering is a highly used knowledge extraction technique and is applied in more and more application domains. Over the last years, a lot of algorithms have been proposed that are often complicated and/or tailored to specific scenarios. As a result, ...
 
Using Cloud Technologies to Optimize Data-Intensive Service Applications
Found in: Cloud Computing, IEEE International Conference on
By Dirk Habich, Wolfgang Lehner, Sebastian Richly, Uwe Assmann
Issue Date:July 2010
pp. 19-26
The role of data analytics increases in several application domains to cope with the large amount of captured data. Generally, data analytics are data-intensive processes, whose efficient execution is a challenging task. Each process consists of a collecti...
 
Database as a service (DBaaS)
Found in: Data Engineering, International Conference on
By Wolfgang Lehner, Kai-Uwe Sattler
Issue Date:March 2010
pp. 1216-1217
Modern Web or “Eternal-Beta” applications necessitate a flexible and easy-to-use data management platform that allows the evolutionary development of databases and applications. The classical approach of relational database systems following strictly the A...
 
Global Slope Change Synopses for Measurement Maps
Found in: Data Mining, IEEE International Conference on
By Frank Rosenthal, Ulrike Fischer, Peter B. Volk, Wolfgang Lehner
Issue Date:December 2009
pp. 956-961
Quality control using scalar quality measures is standard practice in manufacturing. However, there are also quality measures that are determined at a large number of positions on a product, since the spatial distribution is important. We denote such a map...
 
How to Optimize the Quality of Sensor Data Streams
Found in: Computing in the Global Information Technology, International Multi-Conference on
By Anja Klein, Wolfgang Lehner
Issue Date:August 2009
pp. 13-19
Present data stream management systems allow the automatic recording and processing of huge data volumes to guide any kind of process control or business decision. However, a crucial problem is posed by data quality deficiencies due to imprecise sensors, e...
 
Standing Processes in Service-Oriented Environments
Found in: Services, IEEE Congress on
By Steffen Preißler, Dirk Habich, Wolfgang Lehner
Issue Date:July 2009
pp. 115-122
Current realization techniques for service-oriented architectures (SOA) and business process management (BPM) cannot be efficiently applied to any kind of application scenario. For example, an important requirement in the finance sector is the continuous e...
 
Clustering Uncertain Data with Possible Worlds
Found in: Data Engineering, International Conference on
By Peter Benjamin Volk, Frank Rosenthal, Martin Hahmann, Dirk Habich, Wolfgang Lehner
Issue Date:April 2009
pp. 1625-1632
The topic of managing uncertain data has been explored in many ways. Different methodologies for data storage and query processing have been proposed. As the availability of management systems grows, the research on analytics of uncertain data is gaining i...
 
Exploiting Graphic Card Processor Technology to Accelerate Data Mining Queries in SAP NetWeaver BIA
Found in: Data Mining Workshops, International Conference on
By Christoph Weyerhaeuser, Tobias Mindnich, Franz Faerber, Wolfgang Lehner
Issue Date:December 2008
pp. 506-515
Within Business Intelligence contexts, the importance of data mining algorithms is continuously increasing, particularly from the perspective of applications and users that demand novel algorithms on the one hand and an efficient implementation exploiting ...
 
Poster session: Constrained dynamic physical database design
Found in: Data Engineering Workshops, 22nd International Conference on
By Hannes Voigt, Wolfgang Lehner, Kenneth Salem
Issue Date:April 2008
pp. 63-70
Physical design has always been an important part of database administration. Today’s commercial database management systems offer physical design tools, which recommend a physical design for a given workload. However, these tools work only with static wor...
 
RiTE: Providing On-Demand Data for Right-Time Data Warehousing
Found in: Data Engineering, International Conference on
By Christian Thomsen, Torben Bach Pedersen, Wolfgang Lehner
Issue Date:April 2008
pp. 456-465
Data warehouses (DWs) have traditionally been loaded with data at regular time intervals, e.g., monthly, weekly, or daily, using fast bulk loading techniques. Recently, the trend is to insert all (or only some) new source data very quickly into DWs, called...
 
DIPBench Toolsuite: A Framework for Benchmarking Integration Systems
Found in: Data Engineering, International Conference on
By Matthias Bohm, Dirk Habich, Wolfgang Lehner, Uwe Wloka
Issue Date:April 2008
pp. 1596-1599
So far the optimization of integration processes between heterogeneous data sources is still an open challenge. A first step towards sufficient techniques was the specification of a universal benchmark for integration systems. This DIPBench allows to compa...
 
Designing Random Sample Synopses with Outliers
Found in: Data Engineering, International Conference on
By Philipp Rosch, Rainer Gemulla, Wolfgang Lehner
Issue Date:April 2008
pp. 1400-1402
Random sampling is one of the most widely used means to build synopses of large datasets because random samples can be used for a wide range of analytical tasks. Unfortunately, the quality of the estimates derived from a sample is negatively affected by th...
 
Error-Aware Density-Based Clustering of Imprecise Measurement Values
Found in: Data Mining Workshops, International Conference on
By Dirk Habich, Peter B. Volk, Wolfgang Lehner, Ralf Dittmann, Clemens Utzny
Issue Date:October 2007
pp. 471-476
Manufacturing process development is under constant pressure to achieve a good yield for stable processes. The development of new technologies, especially in the field of photomask and semiconductor development, is at its phys- ical limits. In this area, d...
 
Data-Grey-BoxWeb Services in Data-Centric Environments
Found in: Web Services, IEEE International Conference on
By Dirk Habich, Steffen Preissler, Wolfgang Lehner, Sebastian Richly, Uwe Assmann, Mike Grasselt, Albert Maier
Issue Date:July 2007
pp. 976-983
In data-centric environments, for example, in the field of scientific computing, the transmission of large amount of structured data to Web services is required. In serviceoriented environments (SOA), the Simple Object Access Protocol (SOAP) is commonly us...
 
QDM: A Generic QoS-Aware Data Model for Real-Time Data Stream Processing
Found in: Digital Telecommunications, International Conference on
By Sven Schmidt, Benjamin Schlegel, Wolfgang Lehner
Issue Date:July 2007
pp. 31
Data Stream processing addresses a huge variety of application, ranging from processing complex-structured business events to high-volume RFID tag info streams. Some application areas, especially in telecommunication or manufacturing, require guarantees wi...
 
Data-aware SOA for Gene Expression Analysis Processes
Found in: Services, IEEE Congress on
By Dirk Habich, Sebastian Richly, Wolfgang Lehner, Uwe Assmann, Mike Grasselt, Albert Maier, Christian Pilarsky
Issue Date:July 2007
pp. 138-145
In the context of genome research, the method of gene expression analysis has been used for several years. Related microarray experiments are conducted all over the world, and consequently, a vast amount of microarray data sets are produced. Having access ...
 
Representing Data Quality for Streaming and Static Data
Found in: Data Engineering Workshops, 22nd International Conference on
By Anja Klein, Hong-Hai Do, Gregor Hackenbroich, Marcel Karnstedt, Wolfgang Lehner
Issue Date:April 2007
pp. 3-10
In smart item environments, multitude of sensors are applied to capture data about product conditions and usage to guide business decisions as well as production automation processes. A big issue in this application area is posed by the restricted quality ...
 
Shrinked Data Marts Enabled for Negative Caching
Found in: Database Engineering and Applications Symposium, International
By Maik Thiele, Wolfgang Lehner
Issue Date:December 2006
pp. 148-157
Data marts storing pre-aggregated data, prepared for further roll-ups, play an essential role in data warehouse environments and lead to significant performance gains in the query evaluation. However, in order to ensure the completeness of query results on...
 
Optimistic Coarse-Grained Cache Semantics for Data Marts
Found in: Scientific and Statistical Database Management, International Conference on
By Maik Thiele, Jens Albrecht, Wolfgang Lehner
Issue Date:July 2006
pp. 311-320
Data marts and caching are two closely related concepts in the domain of multi-dimensional data. Both store precomputed data to provide fast response times for complex OLAP queries, and for both it must be guaranteed that every query can be completely proc...
 
Materialized Views in the Presence of Reporting Functions
Found in: Scientific and Statistical Database Management, International Conference on
By Dirk Habich, Wolfgang Lehner, Michael Just
Issue Date:July 2006
pp. 159-168
Materialized views are a well-known optimization strategy with the potential for massive improvements in query processing time, especially for aggregation queries over large tables. To realize this potential, the query optimizer has to know how and when to...
 
Real-Time Scheduling for Data Stream Management Systems
Found in: Real-Time Systems, Euromicro Conference on
By Sven Schmidt, Thomas Legler, Daniel Schaller, Wolfgang Lehner
Issue Date:July 2005
pp. 167-176
Quality-aware management of data streams is gaining more and more importance with the amount of data produced by streams growing continuously. The resources required for data stream processing depend on different factors and are limited by the environment ...
 
Database Support for 3D-Protein Data Set Analysis
Found in: Scientific and Statistical Database Management, International Conference on
By Alexander Hinneburg, Wolfgang Lehner
Issue Date:July 2003
pp. 161
The progress in genome research demands for an adequate infrastructure to analyse the data sets. Database systems reflect a key technology to organize data and speed up the analysis process.<div></div> This paper discusses the role of a relatio...
 
On Solving the View Selection Problem in Distributed Data Warehouse Architectures
Found in: Scientific and Statistical Database Management, International Conference on
By Andreas Bauer, Wolfgang Lehner
Issue Date:July 2003
pp. 43
The use of materialized views in a data warehouse installation is a common tool to speed up mostly aggregation queries. The problems coming along with materialized aggregate views have triggered a huge variety of proposals, such as picking the optimal set ...
 
Building a real Data warehouse for Market Research
Found in: Database and Expert Systems Applications, International Workshop on
By Jens Albrecht, Wolfgang Lehner, Michael Teschke, Thomas Kirsche
Issue Date:September 1997
pp. 651
This paper reflects the results of the evaluation phase of building a data production system for the retail research division of the GfK, Europe's largest market research company. The application specific requirements like end-user needs or data volume are...
 
Cinderella — Adaptive online partitioning of irregularly structured data
Found in: 2014 IEEE 30th International Conference on Data Engineering Workshops (ICDEW)
By Kai Herrmann,Hannes Voigt,Wolfgang Lehner
Issue Date:March 2014
pp. 284-291
In an increasing number of use cases, databases face the challenge of managing irregularly structured data. Irregularly structured data is characterized by a quickly evolving variety of entities without a common set of attributes. These entities do not sho...
   
Improving in-memory database index performance with Intel ® Transactional Synchronization Extensions
Found in: 2014 IEEE 20th International Symposium on High Performance Computer Architecture (HPCA)
By Tomas Karnagel,Roman Dementiev,Ravi Rajwar,Konrad Lai,Thomas Legler,Benjamin Schlegel,Wolfgang Lehner
Issue Date:February 2014
pp. 476-487
The increasing number of cores every generation poses challenges for high-performance in-memory database systems. While these systems use sophisticated high-level algorithms to partition a query or run multiple queries in parallel, they also utilize low-le...
   
An Approach for Incremental Semi-supervised SVM
Found in: Data Mining Workshops, International Conference on
By Wael Emara, Mehmed Kantardzic Marcel Karnstedt, Kai-Uwe Sattler, Dirk Habich, Wolfgang Lehner
Issue Date:October 2007
pp. 539-544
In this paper we propose an approach for incremental learning of semi-supervised SVM. The proposed approach makes use of the locality of radial basis function kernels to do local and incremental training of semi-supervised support vector machines. The algo...
 
Maintenance of cube automatic summary tables
Found in: Proceedings of the 2000 ACM SIGMOD international conference on Management of data (SIGMOD '00)
By Hamid Pirahesh, Richard Sidle, Roberta Wolfgang Cochrane, Wolfgang Lehner
Issue Date:May 2000
pp. 245-253
Materialized views (or Automatic Summary Tables---ASTs) are commonly used to improve the performance of aggregation queries by orders of magnitude. In contrast to regular tables, ASTs are synchronized by the database system. In this paper, we present techn...
     
DeExcelerator: a framework for extracting relational data from partially structured documents
Found in: Proceedings of the 22nd ACM international conference on Conference on information & knowledge management (CIKM '13)
By Julian Eberius, Lars Dannecker, Christoper Werner, Katrin Braunschweig, Maik Thiele, Wolfgang Lehner
Issue Date:October 2013
pp. 2477-2480
Of the structured data published on the web, for instance as datasets on Open Data Platforms such as data.gov, but also in the form of HTML tables on the general web, only a small part is in a relational form. Instead the data is intermingled with formatti...
     
Efficient forecasting for hierarchical time series
Found in: Proceedings of the 22nd ACM international conference on Conference on information & knowledge management (CIKM '13)
By Gregor Hackenbroich, Lars Dannecker, Philipp Rösch, Robert Lorenz, Wolfgang Lehner
Issue Date:October 2013
pp. 2399-2404
Forecasting is used as the basis for business planning in many application areas such as energy, sales and traffic management. Time series data used in these areas is often hierarchically organized and thus, aggregated along the hierarchy levels based on t...
     
pEDM: online-forecasting for smart energy analytics
Found in: Proceedings of the 22nd ACM international conference on Conference on information & knowledge management (CIKM '13)
By Gordon Gaumnitz, Gregor Hackenbroich, Lars Dannecker, Philipp Rösch, Ulrike Fischer, Wolfgang Lehner
Issue Date:October 2013
pp. 2411-2416
Continuous balancing of energy demand and supply is a fundamental prerequisite for the stability of energy grids and requires accurate forecasts of electricity consumption and production at any point in time. Today's Energy Data Management (EDM) systems al...
     
pcApriori: scalable apriori for multiprocessor systems
Found in: Proceedings of the 25th International Conference on Scientific and Statistical Database Management (SSDBM)
By Benjamin Schlegel, Thomas Kissinger, Tim Kiefer, Wolfgang Lehner
Issue Date:July 2013
pp. 1-12
Frequent-itemset mining is an important part of data mining. It is a computational and memory intensive task and has a large number of scientific and statistical application areas. In many of them, the datasets can easily grow up to tens or even several hu...
     
SMIX: self-managing indexes for dynamic workloads
Found in: Proceedings of the 25th International Conference on Scientific and Statistical Database Management (SSDBM)
By Hannes Voigt, Thomas Kissinger, Wolfgang Lehner
Issue Date:July 2013
pp. 1-12
As databases accumulate growing amounts of data at an increasing rate, adaptive indexing becomes more and more important. At the same time, applications and their use get more agile and flexible, resulting in less steady and less predictable workload chara...
     
Forecasting in hierarchical environments
Found in: Proceedings of the 25th International Conference on Scientific and Statistical Database Management (SSDBM)
By Benjamin Schlegel, Gregor Hackenbroich, Lars Dannecker, Philipp Rösch, Robert Lorenz, Wolfgang Lehner
Issue Date:July 2013
pp. 1-4
Forecasting is an important data analysis technique and serves as the basis for business planning in many application areas such as energy, sales and traffic management. The currently employed statistical models already provide very accurate predictions, b...
     
Publish-time data integration for open data platforms
Found in: Proceedings of the 2nd International Workshop on Open Data (WOD '13)
By Julian Eberius, Katrin Braunschweig, Maik Thiele, Patrick Damme, Wolfgang Lehner
Issue Date:June 2013
pp. 1-6
Platforms for publication and collaborative management of data, such as Data.gov or Google Fusion Tables, are a new trend on the web. They manage very large corpora of datasets, but often lack an integrated schema, ontology, or even just common publication...
     
Sample-based forecasting exploiting hierarchical time series
Found in: Proceedings of the 16th International Database Engineering & Applications Sysmposium (IDEAS '12)
By Frank Rosenthal, Ulrike Fischer, Wolfgang Lehner
Issue Date:August 2012
pp. 120-129
Time series forecasting is challenging as sophisticated forecast models are computationally expensive to build. Recent research has addressed the integration of forecasting inside a DBMS. One main benefit is that models can be created once and then repeate...
     
Identifying and weighting integration hypotheses on open data platforms
Found in: Proceedings of the First International Workshop on Open Data (WOD '12)
By Julian Eberius, Katrin Braunschweig, Maik Thiele, Wolfgang Lehner
Issue Date:May 2012
pp. 22-29
Open data platforms such as data.gov or opendata.socrata. com provide a huge amount of valuable information, publicly available to anyone. This data has the potential to drive innovation and lead to a more democratic and transparent society. Still, the pla...
     
Data management in the MIRABEL smart grid system
Found in: Proceedings of the 2012 Joint EDBT/ICDT Workshops (EDBT-ICDT '12)
By Andreas Doms, Bogdan Filipič, Erik Dovgan, Lars Dannecker, Laurynas Šikšnys, Matthias Boehm, Tea Tušar, Torben Bach Pedersen, Ulrike Fischer, Wolfgang Lehner, Yoann Pitarch
Issue Date:March 2012
pp. 95-102
Nowadays, Renewable Energy Sources (RES) are attracting more and more interest. Thus, many countries aim to increase the share of green energy and have to face with several challenges (e.g., balancing, storage, pricing). In this paper, we address the balan...
     
Memory-efficient frequent-itemset mining
Found in: Proceedings of the 14th International Conference on Extending Database Technology (EDBT/ICDT '11)
By Benjamin Schlegel, Rainer Gemulla, Wolfgang Lehner
Issue Date:March 2011
pp. 461-472
Efficient discovery of frequent itemsets in large datasets is a key component of many data mining tasks. In-core algorithms---which operate entirely in main memory and avoid expensive disk accesses---and in particular the prefix tree-based algorithm FP-gro...
     
How to juggle columns: an entropy-based approach for table compression
Found in: Proceedings of the Fourteenth International Database Engineering & Applications Symposium (IDEAS '10)
By Alexander Zeier, Christian Lemke, Hasso Plattner, Jens Krueger, Kai-Uwe Sattler, Marcus Paradies, Wolfgang Lehner
Issue Date:August 2010
pp. 205-215
Many relational databases exhibit complex dependencies between data attributes, caused either by the nature of the underlying data or by explicitly denormalized schemas. In data warehouse scenarios, calculated key figures may be materialized or hierarchy l...
     
Cherry picking in database languages
Found in: Proceedings of the Fourteenth International Database Engineering & Applications Symposium (IDEAS '10)
By Bernhard Jaecksch, Franz Faerber, Wolfgang Lehner
Issue Date:August 2010
pp. 117-122
To avoid expensive round-trips between the application layer and the database layer it is crucial that data-intensive processing and calculations happen close to where the data resides -- ideally within the database engine. However, each application has it...
     
Indexing forecast models for matching and maintenance
Found in: Proceedings of the Fourteenth International Database Engineering & Applications Symposium (IDEAS '10)
By Frank Rosenthal, Matthias Boehm, Ulrike Fischer, Wolfgang Lehner
Issue Date:August 2010
pp. 26-31
Forecasts are important to decision-making and risk assessment in many domains. There has been recent interest in integrating forecast queries inside a DBMS. Answering a forecast query requires the creation of forecast models. Creating a forecast model is ...
     
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