Mon. - Fri.: 8.30 a.m. - 1.30 p.m. and by appointment

Opening hours of the Dean's Office and Master's Secretariat:

Monday to Wednesday from 9:00 am to 12:00 pm - Other appointments by arrangement!

Thursday - Appointments by arrangement!

Friday - closed

During exam and lecture-free times: Appointments by appointment only!

Visitor address:
Technische Hochschule Mittelhessen,
departement of Business | THM Business School,
Eichgärtenallee 6 - Building C50 | Room 1.03,
35394 Gießen

Postal address:
Technische Hochschule Mittelhessen,
departement Business | THM Business School,
Wiesenstraße 14,
35390 Gießen

Internship in Auditing

https://www.expedition-wirtschaft.de/insightday-plaetze/

08/1991 - 08/1994

University of Applied Sciences for Finance NRW, Nordkirchen; Degree: Diploma in Finance (FH)

08/1994 - 10/1994

Tax inspector in the income tax district of the North Rhine-Westphalia tax administration

 10/1994 - 04/1999

Studied business administration at the Westphalian Wilhelms University of Münster; graduated with a degree in business administration (Diplom-Kaufmann)

 05/1999 - 03/2008

Deloitte, Düsseldorf and Frankfurt am Main, Auditing

04/2002 Appointment as tax advisor

02/2004 Appointment as auditor

07/2008 - 03/2010

PricewaterhouseCoopers (PwC), Frankfurt am Main, Auditing , National Office

06/2009 Dissertation, Technical University of Dortmund

since 04/2010

Technical University of Central Hesse (THM), Department of Economics, Gießen

Office hours by appointment; please send me a short email stating the topic or speak to me personally during the lecture break.

Current research:

(0) Preprints:

- Measuring Bell non-locality in the presence of signaling (March 1, 2026) http://arxiv.org/abs/2603.00984 

(1) International publications with peer-review process: 

- Widdows, D., Pothos, EM, and Gallus, C. Understanding Connections Between Market Price Liquidity and Volatility: Can Quantum-Inspired Models Help? Quantum Economics and Finance, 2026.
https://doi.org/10.1177/29767032261444324

- Zarifian, A., Gallus, C., Overbeck, L., Pothos, EM and Blasiak, P. Using Bell violations as an indicator for financial market crisis. The Journal of Finance and Data Science, 2025.  https://www.sciencedirect.com/science/article/pii/S2405918825000169

- Gallus, C., Pothos, EM, Ebelt, Z., Skouteris, D., and Blasiak, P. Probability Updating in the Classical and the Quantum Model. Quantum Economics and Finance, 2024. https://doi.org/10.1177/29767032241292040

- Blasiak, P. and Gallus, C., Phil. Trans. R. Soc. A, 2024:
https://royalsocietypublishing.org/doi/10.1098/rsta.2023.0005

- Gallus, C., Blasiak, P. and Pothos, EM, Entropy 2023, 25, 824: https://www.mdpi.com/1099-4300/25/5/824 

- Gallus, C., Pothos, EM, Blasiak, P., Yearsley, JM, and Wojciechowski, BW, Scientific Reports 2023, 13, 4394: https://www.nature.com/articles/s41598-023-31441-x

- Gallus, C., Blasiak, P. and Pothos, EM, Entropy 2022, 24 (3), 364: https://www.mdpi.com/1099-4300/24/3/364

- Blasiak, P., Pothos, EM, Yearsley, JM, Gallus, C. and Borsuk, E., PNAS 2021, 118 (17):  https://www.pnas.org/doi/10.1073/pnas.2020569118

(2) German-language introduction, published as volume 16 in the THM university publications: http://digdok.bib.thm.de/volltexte/2021/5382/ 

CV:

During the lecture period: Wed, 1 p.m. - 2 p.m., otherwise by appointment

Please register in advance by email.

I have been a member of the Executive Board since April 2025:

https://www.thm.de/site/hochschule/zentrale-bereiche/praesidium/vizepraesidentin-prof-dr-stephanie-hanrath.html

By appointment - please register by email stating your request.

Wednesdays by prior arrangement via email.

majors :

• Controlling, cost accounting and cost management
• Strategy transmission and strategic controlling
• Digitalization in controlling, in particular its influence on controlling instruments and their use and application
• Controlling effect of controlling instruments

Kachel, 2017, The selection of controlling instruments for strategy transmission in medium-sized family businesses, Shaker Verlag, Aachen.

Hoch/Heupel/Kachel, 2016, Life-Cycle-Costing in corporate practice: techniques, strategic importance, implementation problems, pages 329 - 344, in Becker/Ulrich (eds.), Handbook of Controlling, Springer Gabler Verlag, Wiesbaden.

• Since summer semester 2025: Professor of general business administration and controlling at THM
• 2015 - 2025 Head of Strategic Controlling at Stabilus SE
• 2011 - 2015 Research Assistant at the Chair of Management Accounting at the University of Siegen
• 2009 - 2011 Trainee program in Strategic Controlling at ThyssenKrupp Rasselstein GmbH
• 2005 - 2010 Studies at Koblenz University of Applied Sciences (B.Sc. and M.Sc.)
• 2001 - 2005 Commercial apprenticeship/commercial employee

Office hours by appointment!

Open topics for theses (as of 01.03.2025)

1) Analysis of the current state of research on the use of humanoids and social robots from a behavioral perspective with a focus on the healthcare
goal is a comprehensive research on the current research and development level as well as comparative preparation of relevant literature and studies.

Target group: Bachelor and Master (Madi, Dima, Map)

2) Conducting an acceptance study on social robots for communication and information tasks in inpatient healthcare.
A Furhat robot connected to a generative language model will be operated in the waiting area of ​​Braunfels Hospital. The reactions and acceptance of the participants will be analyzed within the framework of a methodologically sound behavioral study.

Target group: Master (Madi, Maim, Map, dima)

3) Development of an internationally oriented business model for drone- and AI-supported logistics, inspection, and monitoring services in conjunction with Mobile Private Networks in the primary sector and for raw material extraction (already in progress).
Raw material extraction companies often operate in remote regions and therefore have limited IT infrastructure. At the same time, the extraction areas often extend over large and sometimes inaccessible areas. This results in particular challenges, for example, in the inspection of machinery and equipment, their safety monitoring, and in various logistics tasks (e.g., inventory).
The use of AI-supported drones allows parts of these processes to be automated. This generally requires so-called Mobile Private Networks (MPNs) or campus networks based on 5G. The thesis aims to evaluate and design possibilities for developing a corresponding business model. The Business Model Canvas serves as the methodological basis.

Target group: Master (Madi)

4) Development of a business model for the use of the social robot Furhat in conjunction with generative AI models (in progress)
Robotics is considered a promising field of application for AI systems. Currently, many manufacturers are primarily focused Major physical, labor-intensive tasks (e.g., warehouse management or assembly work). The use of robots for communicative service tasks, on the other hand, is still receiving little attention.
This thesis aims to develop a concept for building a corresponding business model using the Business Model Canvas.

Target group: Bachelor and Master (Madi, Dima)

5) Development of a chatbot for communication with an enterprise resource planning (ERP) system as a backend for an online shop (in progress)
The rapid development of generative AI systems will fundamentally change the internet and its use in the near future. In contrast to currently leading systems (Frontier AI), the focus here is on integrating local data sources – while taking data protection into account.
A relevant technological approach is so-called "Retrieval Augmented Generation." This allows local documents to be integrated into on-premises, open-source language models. Initial frameworks already enable the implementation of such systems without in-depth programming knowledge. THM Business School has relevant experience in this area.
Building on previous projects, a thesis will investigate to what extent such a framework can be used to integrate databases from commercial applications. The database of an online shop for dietary supplements can be used as a concrete practical example.

Specific requirements: SQL knowledge (such as that taught in the Business Intelligence module) is required for this topic!

Target group: Master (Madi, Mauf, Dima)

Scharf, P., Keller, S.: PPS implementation in medium-sized production companies. In: VDI-Z 03, Düsseldorf: Springer-VDI-Verlag, 1999

Keller, S.: Development of a method for the integrated modeling of structures and processes in production companies. VDI-Verlag, Düsseldorf (Dissertation). 2000

Keller, S.: eNORM - Standards management for manufacturing companies and industry associations. In: Journal for DIN 40. Beuth-Verlag. Berlin. 2001

Keller, S.: Capacity planning – planning small-batch production efficiently and promptly. In: Maschinenmarkt 24. Vogel-Verlag. Würzburg. 2001

Keller, S.: Holistic e-business strategies for Medium-Sized Companies . In: VDI-Z 08. Springer-VDI-Verlag. Düsseldorf. 2001

Keller, S.: E-Procurement – ​​Current State of Use in Manufacturing Companies. In: Proceedings of the 2nd Siegen Forum for Logistics Electronic Procurement – ​​Application Potentials, Perspectives and Limitations. Siegen. 2002. Keller, S.:

The Plagues of the Digital Age. In: Study and Practice. Giessen. 2003

Keller, S.: Planning and controlling in single-unit and small-batch production. In: Industrieanzeiger 09. Konradin-Verlag, Leinfelden-Echterdingen. 2005

Keller, S., Trayser, B.: Online banking in user testing. bank und markt 03. Knapp & Richardi Publishers, Frankfurt. 2005

Keller, S.: Physician networks and integrated care: Between aspiration and reality. In: Deutsches Ärzteblatt 109, Berlin/Cologne 2012

Keller, S.: Concerted pharmacotherapy in physician networks. In: Health Economics & Quality Management, Issue 3. Thieme-Verlag, Stuttgart, May 2012

Keller, S.: Modern IT developments and their influence on the economy and society; pp. 23–52; in: Digitalization: Data hype with loss of value?: Ethical perspectives for a key technology; Haupt, R. and Schmitz, St. (eds.); SCM-Hänssler 2019

Keller, S., Lorenz, A.: Study on the state of knowledge and use of artificial intelligence in the Central Hessian economy and the adjacent Siegerland region - Analysis of the AI ​​maturity of companies within the framework of a qualitative study; THM University Publications

By appointment, please contact us via email

• Work majors :
  • Business information processing
  • Project management
  • Business process management
  • Use of modeling languages ​​in organization and software/database development
  • Data management, data architecture design
  • Database management systems
  • Software Engineering
• Foreign Affairs Officer of the departement for Great Britain and Ireland
• Member of the THM working group on internationalization to promote the internationalization of the university (across departement )
• Publicly appointed and sworn (ö.buv) experts for information processing - systems and applications
• Member of the Information Processing Expert Committee of the Chambers of Industry and Commerce