Clemens Lutz

dblp:165/8314 · DBLP profile ↗
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9ranked-venue papers
3as first author
5since 2021 · last 2025
0000-0002-6193-4734ORCID · corroborated

Domains — the database's venue-derived domains; a paper can count in several

Databases, data management, data science and information retrieval · 7 · 3 first-author · 4 since 2021Artificial intelligence and machine learning · 1 · 1 since 2021Systems, architecture and hardware · 1Graphics, computer vision, multimedia, augmented reality and games · 1 · 1 since 2021
YearPublicationVenuePosition
2025 Efficiently Indexing Large Data on GPUs with Fast Interconnects
Josef Schmeißer, Clemens Lutz, Volker Markl
EDBT2
2024 Benchmarking Stream Join Algorithms on GPUs: A Framework and its Application to the State-of-the-art
Dwi P. A. Nugroho, Philipp M. Grulich, Steffen Zeuch, Clemens Lutz, Stefano Bortoli, Volker Markl
EDBT4
2024 Temporal Co-Registration of Simultaneous Electromagnetic Articulography and Electroencephalography for Precise Articulatory and Neural Data Alignment
abstract
This study presents a temporal co-registration method combining electromagnetic articulography (EMA) and electroencephalography (EEG) to capture the neural planning and execution phases of speech with high precision. Traditional EEG alignment based on acoustic vocal onset is often inaccurate due to the variable lag between articulatory and acoustic onsets. Our approach synchronizes EMA-derived speech kinematics with EEG data, addressing these challenges. We also examined the interaction between EMA and EEG systems, focusing on the integrity of EMA signals in the presence of EEG equipment and the electromagnetic influence of EMA on EEG signal quality. The method achieved a mean alignment delay of 2.7 ms (SD = 0.4 ms), enabling detailed analysis of pre-articulatory brain activities. Additionally, our evaluations confirmed the robustness of EMA signals and EEG event-related potentials, supporting the method's precision, feasibility, and reliability for speech planning research.
Daniel Friedrichs, Monica Lancheros, Sam Kirkham, Lei He 0021, Clemens Lutz, Volker Dellwo, Steven Moran
INTERSPEECH6
2022 Triton Join: Efficiently Scaling to a Large Join State on GPUs with Fast Interconnects
abstract
Database management systems are facing growing data volumes. Previous research suggests that GPUs are well-equipped to quickly process joins and similar stateful operators, as GPUs feature high-bandwidth on-board memory. However, GPUs cannot scale joins to large data volumes due to two limiting factors: (1)~large state does not fit into the on-board memory, and (2)~spilling state to main memory is constrained by the interconnect bandwidth. Thus, CPUs are often the better choice for scalable data processing.
Clemens Lutz, Sebastian Breß, Steffen Zeuch, Tilmann Rabl, Volker Markl
SIGMOD Conference1
2021 An Energy-Efficient Stream Join for the Internet of Things
abstract
The Internet of Things (IoT) combines large data centers with (mobile, networked) edge devices that are constrained both in compute power and energy budget. Modern edge devices contribute to query processing by leveraging accelerated processing units with multicore CPUs or GPUs. Therefore, data processing in the IoT presents the challenges of 1) minimizing the energy consumed while sustaining a given query throughput, and 2) processing increasingly complex queries within a given energy budget.
Adrian Michalke, Philipp M. Grulich, Clemens Lutz, Steffen Zeuch, Volker Markl
DaMoN3
2020 Pump Up the Volume: Processing Large Data on GPUs with Fast Interconnects
abstract
GPUs have long been discussed as accelerators for database query processing because of their high processing power and memory bandwidth. However, two main challenges limit the utility of GPUs for large-scale data processing: (1) the on-board memory capacity is too small to store large data sets, yet (2) the interconnect bandwidth to CPU main-memory is insufficient for ad hoc data transfers. As a result, GPU-based systems and algorithms run into a transfer bottleneck and do not scale to large data sets. In practice, CPUs process large-scale data faster than GPUs with current technology. In this paper, we investigate how a fast interconnect can resolve these scalability limitations using the example of NVLink 2.0. NVLink 2.0 is a new interconnect technology that links dedicated GPUs to a [email protected] The high bandwidth of NVLink 2.0 enables us to overcome the transfer bottleneck and to efficiently process large data sets stored in main-memory on GPUs. We perform an in-depth analysis of NVLink 2.0 and show how we can scale a no-partitioning hash join beyond the limits of GPU memory. Our evaluation shows speed-ups of up to 18x over PCI-e 3.0 and up to 7.3x over an optimized CPU implementation. Fast GPU interconnects thus enable GPUs to efficiently accelerate query processing.
Clemens Lutz, Sebastian Breß, Steffen Zeuch, Tilmann Rabl, Volker Markl
SIGMOD Conference1
2019 Analyzing Efficient Stream Processing on Modern Hardware
abstract
Modern Stream Processing Engines (SPEs) process large data volumes under tight latency constraints. Many SPEs execute processing pipelines using message passing on shared-nothing architectures and apply a partition-based scale-out strategy to handle high-velocity input streams. Furthermore, many state-of-the-art SPEs rely on a Java Virtual Machine to achieve platform independence and speed up system development by abstracting from the underlying hardware. In this paper, we show that taking the underlying hardware into account is essential to exploit modern hardware efficiently. To this end, we conduct an extensive experimental analysis of current SPEs and SPE design alternatives optimized for modern hardware. Our analysis highlights potential bottlenecks and reveals that state-of-the-art SPEs are not capable of fully exploiting current and emerging hardware trends, such as multi-core processors and high-speed networks. Based on our analysis, we describe a set of design changes to the common architecture of SPEs to scale-up on modern hardware. We show that the single-node throughput can be increased by up to two orders of magnitude compared to state-of-the-art SPEs by applying specialized code generation, fusing operators, batch-style parallelization strategies, and optimized windowing. This speedup allows for deploying typical streaming applications on a single or a few nodes instead of large clusters.
Steffen Zeuch, Sebastian Breß, Tilmann Rabl, Bonaventura Del Monte, Jeyhun Karimov, Clemens Lutz, Manuel Renz, Jonas Traub, Volker Markl
Proc. VLDB Endow.6
2018 Efficient k-means on GPUs
abstract
k-Means is a versatile clustering algorithm widely-used in practice. To cluster large data sets, state-of-the-art implementations use GPUs to shorten the data to knowledge time. These implementations commonly assign points on a GPU and update centroids on a CPU.
Clemens Lutz, Sebastian Breß, Tilmann Rabl, Steffen Zeuch, Volker Markl
DaMoN1
2015 RStore: A Direct-Access DRAM-based Data Store
abstract
Distributed DRAM stores have become an attractive option for providing fast data accesses to analytics applications. To accelerate the performance of these stores, researchers have proposed using RDMA technology. RDMA offers high bandwidth and low latency data access by carefully separating resource setup from IO operations, and making IO operations fast by using rich network semantics and offloading. Despite recent interest, leveraging the full potential of RDMA in a distributed environment remains a challenging task. In this paper, we present RDMA Store or RStore, a DRAM-based data store that delivers high performance by extending RDMA's separation philosophy to a distributed setting. RStore achieves high aggregate bandwidth (705 Gb/s) and close-to-hardware latency on our 12-machine testbed. We developed a distributed graph processing framework and a Key-Value sorter using RStore's unique memory-like API. The graph processing framework, which relies on RStore for low-latency graph access, outperforms state-of-the-art systems by margins of 2.6 -- 4.2× when calculating Page Rank. The Key-Value sorter can sort 256 GB of data in 31.7 sec, which is 8× better than Hadoop TeraSort in a similar setting.
Animesh Trivedi, Patrick Stuedi, Bernard Metzler, Clemens Lutz, Martin L. Schmatz, Thomas R. Gross
ICDCS4