Sandra Geisler

Dr. Sandra Geisler


Research Focus & Metrics

Academic Career Length

17Years (2010-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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7 January 2013 in BMC Medical Informatics and Decision Making
Verified
Journal Article
Open access
PDF file
RSRobert Schmidt
Robert Schmidt
SGSandra Geisler
Sandra Geisler
CSCord Spreckelsen
Cord Spreckelsen
Elective patient admission and assignment planning is an important task of the strategic and operational management of a hospital and early on became a central topic of clinical operations research. The management of hospital beds is an important subtask. Various approaches have been proposed, involving the computation of efficient assignments with regard to the patients’ condition, the necessity of the treatment, and the patients’ preferences. However, these approaches are mostly based on static, unadaptable estimates of the length of stay and, thus, do not take into account the uncertainty of the patient’s recovery. Furthermore, the effect of aggregated bed capacities have not been investigated in this context. Computer supported bed management, combining an adaptable length of stay estimation with the treatment of shared resources (aggregated bed capacities) has not yet been sufficiently investigated. The aim of our work is: 1) to define a cost function for patient admission taking into account adaptable length of stay estimations and aggregated resources, 2) to define a mathematical program formally modeling the assignment problem and an architecture for decision support, 3) to investigate four algorithmic methodologies addressing the assignment problem and one base-line approach, and 4) to evaluate these methodologies w.r.t. cost outcome, performance, and dismissal ratio.

23 December 2021 in Journal of Data and Information Quality
Verified
Journal Article
Open access
SGSandra Geisler
Sandra Geisler
MVMaria-Esther Vidal
Maria-Esther Vidal
CCCinzia Cappiello
Cinzia Cappiello
BLBernadette Farias Lóscio
Bernadette Farias Lóscio
AGAvigdor Gal
Avigdor Gal
JRJakob Rehof
Jakob Rehof
A data ecosystem (DE) offers a keystone-player or alliance-driven infrastructure that enables the interaction of different stakeholders and the resolution of interoperability issues among shared data. However, despite years of research in data governance and management, trustability is still affected by the absence of transparent and traceable data-driven pipelines. In this work, we focus on requirements and challenges that DEs face when ensuring data transparency. Requirements are derived from the data and organizational management, as well as from broader legal and ethical considerations. We propose a novel knowledge-driven DE architecture, providing the pillars for satisfying the analyzed requirements. We illustrate the potential of our proposal in a real-world scenario. Last, we discuss and rate the potential of the proposed architecture in the fulfillmentof these requirements.

1 November 2020
Verified
Book Chapter
Closed access
PDF file
SBSebastian R. Bader
Sebastian R. Bader
JPJaroslav Pullmann
Jaroslav Pullmann
CMChristian Mader
Christian Mader
STSebastian Tramp
Sebastian Tramp
Christoph QuixChristoph Quix
Christoph Quix
CLChristoph Lange
Christoph Lange

6 October 2016 in Journal of Data and Information Quality
Verified
Journal Article
Open access
SGSandra Geisler
Sandra Geisler
Christoph QuixChristoph Quix
Christoph Quix
SWSven Weber
Sven Weber
MJMatthias Jarke
Matthias Jarke
Data Stream Management Systems (DSMS) provide real-time data processing in an effective way, but there is always a tradeoff between data quality (DQ) and performance. We propose an ontology-based data quality framework for relational DSMS that includes DQ measurement and monitoring in a transparent, modular, and flexible way. We follow a threefold approach that takes the characteristics of relational data stream management for DQ metrics into account. While (1) Query Metrics respect changes in data quality due to query operations, (2) Content Metrics allow the semantic evaluation of data in the streams. Finally, (3) Application Metrics allow easy user-defined computation of data quality values to account for application specifics. Additionally, a quality monitor allows us to observe data quality values and take counteractions to balance data quality and performance. The framework has been designed along a DQ management methodology suited for data streams. It has been evaluated in the domains of transportation systems and health monitoring.

1 August 2012 in Transportation Research Part C: Emerging Technologies
Verified
Journal Article
Closed access
SGSandra Geisler
Sandra Geisler
Christoph QuixChristoph Quix
Christoph Quix
Stefan SchifferStefan Schiffer
Stefan Schiffer
MJMatthias Jarke
Matthias Jarke

18 June 2023
Verified
Conference Paper
Open access
TSTarek Stolz
Tarek Stolz
IKIstván Koren
István Koren
LTLiam Tirpitz
Liam Tirpitz
SGSandra Geisler
Sandra Geisler
With the increasing prevalence of IoT environments, the demand for processing massive distributed data streams has become a critical challenge. Data Stream Processing on the Edge (DSPoE) systems have emerged as a solution to address this challenge, but they often struggle to cope with the heterogeneity of hardware and platforms. To address this issue, we propose a new hybrid DSPoE architecture named GALOIS, which is based on WebAssembly (Wasm) and is hardware-, platform-, and language-agnostic. GALOIS employs a multi-layered approach that combines P2P and master-worker concepts for communication between components. We present experimental results showing that operators executed in Wasm outperform those in Docker in terms of energy and CPU consumption, making it a promising option for streaming operators in DSPoE. We therefore expect Wasm-based solutions to significantly improve the performance and resilience of DSPoE systems.