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1. Comparing the Performance of Recurrent Neural Network and Some Well-Known Statistical Methods in the Case of Missing Multivariate Time Series Data

Author

Zahmatkesh, Samira, Zech, Philipp, Goos, Gerhard, Series Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Lemaire, Vincent, editor, Ifrim, Georgiana, editor, Bagnall, Anthony, editor, Guyet, Thomas, editor, Malinowski, Simon, editor, Schäfer, Patrick, editor, and Tavenard, Romain, editor

Published
2025
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2. Coupled Requirements-driven Testing of CPS: From Simulation To Reality

Author

Agrawal, Ankit, Zech, Philipp, and Vierhauser, Michael

Subjects
Computer Science - Software Engineering
Abstract

Failures in safety-critical Cyber-Physical Systems (CPS), both software and hardware-related, can lead to severe incidents impacting physical infrastructure or even harming humans. As a result, extensive simulations and field tests need to be conducted, as part of the verification and validation of system requirements, to ensure system safety. However, current simulation and field testing practices, particularly in the domain of small Unmanned Aerial Systems (sUAS), are ad-hoc and lack a thorough, structured testing process. Furthermore, there is a dearth of standard processes and methodologies to inform the design of comprehensive simulation and field tests. This gap in the testing process leads to the deployment of sUAS applications that are: (a) tested in simulation environments which do not adequately capture the real-world complexity, such as environmental factors, due to a lack of tool support; (b) not subjected to a comprehensive range of scenarios during simulation testing to validate the system requirements, due to the absence of a process defining the relationship between requirements and simulation tests; and (c) not analyzed through standard safety analysis processes, because of missing traceability between simulation testing artifacts and safety analysis artifacts. To address these issues, we have developed an initial framework for validating CPS, specifically focusing on sUAS and robotic applications. We demonstrate the suitability of our framework by applying it to an example from the sUAS domain. Our preliminary results confirm the applicability of our framework. We conclude with a research roadmap to outline our next research goals along with our current proposal.

Published
2024

3. Towards a Success Model for Automated Programming Assessment Systems Used as a Formative Assessment Tool

Author

Sauerwein, Clemens, Antensteiner, Tobias, Oppl, Stefan, Groher, Iris, Meschtscherjakov, Alexander, Zech, Philipp, and Breu, Ruth

Subjects
Computer Science - Software Engineering
Abstract

The assessment of source code in university education is a central and important task for lecturers of programming courses. In doing so, educators are confronted with growing numbers of students having increasingly diverse prerequisites, a shortage of tutors, and highly dynamic learning objectives. To support lecturers in meeting these challenges, the use of automated programming assessment systems (APASs), facilitating formative assessments by providing timely, objective feedback, is a promising solution. Measuring the effectiveness and success of these platforms is crucial to understanding how such platforms should be designed, implemented, and used. However, research and practice lack a common understanding of aspects influencing the success of APASs. To address these issues, we have devised a success model for APASs based on established models from information systems as well as blended learning research and conducted an online survey with 414 students using the same APAS. In addition, we examined the role of mediators intervening between technology-, system- or self-related factors, respectively, and the users' satisfaction with APASs. Ultimately, our research has yielded a model of success comprising seven constructs influencing user satisfaction with an APAS.

Published
2023
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4. A Requirements Study on Model Repositories for Digital Twins in Construction Engineering

Author

Zech, Philipp, Fröch, Georg, Breu, Ruth, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Sellami, Mohamed, editor, Vidal, Maria-Esther, editor, van Dongen, Boudewijn, editor, Gaaloul, Walid, editor, and Panetto, Hervé, editor

Published
2024
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8. Action Representations in Robotics: A Taxonomy and Systematic Classification

Author

Zech, Philipp, Renaudo, Erwan, Haller, Simon, Zhang, Xiang, and Piater, Justus

Subjects
Computer Science - Robotics
Abstract

Understanding and defining the meaning of "action" is substantial for robotics research. This becomes utterly evident when aiming at equipping autonomous robots with robust manipulation skills for action execution. Unfortunately, to this day we still lack both a clear understanding of the concept of an action and a set of established criteria that ultimately characterize an action. In this survey we thus first review existing ideas and theories on the notion and meaning of action. Subsequently we discuss the role of action in robotics and attempt to give a seminal definition of action in accordance with its use in robotics research. Given this definition we then introduce a taxonomy for categorizing action representations in robotics along various dimensions. Finally, we provide a systematic literature survey on action representations in robotics where we categorize relevant literature along our taxonomy. After discussing the current state of the art we conclude with an outlook towards promising research directions., Comment: 36 pages, 4 figures, 7 tables, submitted to the International Journal of Robotics Research (IJRR)

Published
2018

9. BIMReason: Validating BIM model correctness.

Author

Zech, Philipp, Burger, Peter, Hammes, Sascha, Geisler‐Moroder, David, and Breu, Ruth

Subjects
*BUILDING information modeling, *SEMANTIC Web, *CONSTRUCTION projects, *DATA modeling, *CRITICAL analysis
Abstract

Compliance inspections and building analysis are critical to the success of any construction project. At present, such assessments are primarily conducted manually by experts in the architecture, engineering and construction (AEC) sector resulting in a tedious, labor‐intensive, and generally inefficient undertaking. Yet, with the gradual adoption of Building Information Modeling (BIM), automated building analysis and compliance checking become feasible. The Industry Foundation Classes (IFC) has received a lot of traction in the AEC industry as a vendor‐neutral data model. Its well‐defined semantics can be exploited by reasoning engines that allow for semantic reasoning on building models, the core mechanism required for automated compliance checking and building analysis. In this paper, a general‐purpose model checking framework for IFC building models, as well as an appropriate specification layout are introduced. Model checking via semantic reasoning is realized using various technologies from the Semantic Web. To present and evaluate our implementation, a sample specification is developed and tested on two IFC building models. [ABSTRACT FROM AUTHOR]

Published
2024
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10. ROSSINI: RobOt kidS deSIgn thiNkIng

Author

Haller-Seeber, Simon, Renaudo, Erwan, Zech, Philipp, Westreicher, Florian, Walzthöni, Markus, Strappler, Stefan, Vidovic, Cornelia, Piater, Justus, Kacprzyk, Janusz, Series Editor, Pal, Nikhil R., Advisory Editor, Bello Perez, Rafael, Advisory Editor, Corchado, Emilio S., Advisory Editor, Hagras, Hani, Advisory Editor, Kóczy, László T., Advisory Editor, Kreinovich, Vladik, Advisory Editor, Lin, Chin-Teng, Advisory Editor, Lu, Jie, Advisory Editor, Melin, Patricia, Advisory Editor, Nedjah, Nadia, Advisory Editor, Nguyen, Ngoc Thanh, Advisory Editor, Wang, Jun, Advisory Editor, Lepuschitz, Wilfried, editor, Merdan, Munir, editor, Koppensteiner, Gottfried, editor, Balogh, Richard, editor, and Obdržálek, David, editor

Published
2021
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11. Active and Transfer Learning of Grasps by Sampling from Demonstration

Author

Zech, Philipp and Piater, Justus

Subjects
Computer Science - Robotics
Abstract

We guess humans start acquiring grasping skills as early as at the infant stage by virtue of two key processes. First, infants attempt to learn grasps for known objects by imitating humans. Secondly, knowledge acquired during this process is reused in learning to grasp novel objects. We argue that these processes of active and transfer learning boil down to a random search of grasps on an object, suitably biased by prior experience. In this paper we introduce active learning of grasps for known objects as well as transfer learning of grasps for novel objects grounded on kernel adaptive, mode-hopping Markov Chain Monte Carlo. Our experiments show promising applicability of our proposed learning methods., Comment: 6 pages, 3 figures, 3 tables, technical report. arXiv admin note: substantial text overlap with arXiv:1611.06366

Published
2016

12. Grasp Learning by Sampling from Demonstration

Author

Zech, Philipp and Piater, Justus

Subjects
Computer Science - Robotics
Abstract

Robotic grasping traditionally relies on object features or shape information for learning new or applying already learned grasps. We argue however that such a strong reliance on object geometric information renders grasping and grasp learning a difficult task in the event of cluttered environments with high uncertainty where reasonable object models are not available. This being so, in this paper we thus investigate the application of model-free stochastic optimization for grasp learning. For this, our proposed learning method requires just a handful of user-demonstrated grasps and an initial prior by a rough sketch of an object's grasp affordance density, yet no object geometric knowledge except for its pose. Our experiments show promising applicability of our proposed learning method., Comment: 6 pages, 3 figures, 2 tables, technical report. arXiv admin note: substantial text overlap with arXiv:1611.06367

Published
2016

13. Active and Transfer Learning of Grasps by Kernel Adaptive MCMC

Author

Zech, Philipp, Xiong, Hanchen, and Piater, Justus

Subjects
Computer Science - Robotics
Abstract

Human ability of both versatile grasping of given objects and grasping of novel (as of yet unseen) objects is truly remarkable. This probably arises from the experience infants gather by actively playing around with diverse objects. Moreover, knowledge acquired during this process is reused during learning of how to grasp novel objects. We conjecture that this combined process of active and transfer learning boils down to a random search around an object, suitably biased by prior experience, to identify promising grasps. In this paper we present an active learning method for learning of grasps for given objects, and a transfer learning method for learning of grasps for novel objects. Our learning methods apply a kernel adaptive Metropolis-Hastings sampler that learns an approximation of the grasps' probability density of an object while drawing grasp proposals from it. The sampler employs simulated annealing to search for globally-optimal grasps. Our empirical results show promising applicability of our proposed learning schemes., Comment: 6 pages, 4 figures, 3 tables, technical report

Published
2016

18. ROSSINI: RobOt kidS deSIgn thiNkIng

Author

Haller-Seeber, Simon, primary, Renaudo, Erwan, additional, Zech, Philipp, additional, Westreicher, Florian, additional, Walzthöni, Markus, additional, Strappler, Stefan, additional, Vidovic, Cornelia, additional, and Piater, Justus, additional

Published
2021
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23. Security Risk Analysis by Logic Programming

Author

Zech, Philipp, Felderer, Michael, Breu, Ruth, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Kobsa, Alfred, Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, Bauer, Thomas, editor, Großmann, Jürgen, editor, Seehusen, Fredrik, editor, Stølen, Ketil, editor, and Wendland, Marc-Florian, editor

Published
2014
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24. A Generic Platform for Model-Based Regression Testing

Author

Zech, Philipp, Felderer, Michael, Kalb, Philipp, Breu, Ruth, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, and Margaria, Tiziana, editor

Published
2012
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28. Recreational Exercising and Self-Reported Cardiometabolic Diseases in German People Living with HIV: A Cross-Sectional Study

Author

Pérez Chaparro, Camilo Germán Alberto, Schuch, Felipe Barreto, Zech, Philipp, Kangas, Maria, Rapp, Michael Armin, Heißel, Andreas, Ermolao, Andrea (Prof. Dr. med.), Neunhaeuserer, Daniel (Dr. med.), and Battista, Francesca

Subjects
exercise, HIV, HIV Infections, metabolic disease, Article, Extern, cardiovascular diseases, Cross-Sectional Studies, sedentary, Medicine, Humans, Self Report, ddc:610, Humanwissenschaftliche Fakultät, 610 Medizin und Gesundheit
Abstract

Exercise is known for its beneficial effects on preventing cardiometabolic diseases (CMDs) in the general population. People living with the human immunodeficiency virus (PLWH) are prone to sedentarism, thus raising their already elevated risk of developing CMDs in comparison to individuals without HIV. The aim of this cross-sectional study was to determine if exercise is associated with reduced risk of self-reported CMDs in a German HIV-positive sample (n = 446). Participants completed a self-report survey to assess exercise levels, date of HIV diagnosis, CD4 cell count, antiretroviral therapy, and CMDs. Participants were classified into exercising or sedentary conditions. Generalized linear models with Poisson regression were conducted to assess the prevalence ratio (PR) of PLWH reporting a CMD. Exercising PLWH were less likely to report a heart arrhythmia for every increase in exercise duration (PR: 0.20: 95% CI: 0.10–0.62, p &lt, 0.01) and diabetes mellitus for every increase in exercise session per week (PR: 0.40: 95% CI: 0.10–1, p &lt, 0.01). Exercise frequency and duration are associated with a decreased risk of reporting arrhythmia and diabetes mellitus in PLWH. Further studies are needed to elucidate the mechanisms underlying exercise as a protective factor for CMDs in PLWH.

Published
2022

31. Real-Time Order Tracking of Gear Mesh Vibration in High Speed Planetary Gearboxes

Author

Plöger Daniel Fritz, Zech Philipp, and Rinderknecht Stephan

Subjects
Engineering (General). Civil engineering (General), TA1-2040
Abstract

Possible approaches to real-time order tracking are discussed. Two methods for real-time order tracking are developed and validated experimentally for the entire audible spectrum. An adaptive heterodyne filter bank is compared to a direct integral transform. The performance of both methods is adequate for usage in an active vibration control (AVC) algorithm. Vold-Kalman filters are not suitable for AVC. The vibration data of three different planetary gearboxes is analyzed using order tracking. While some of the existing research could be reproduced, the data contradicts statements made by several authors. Lastly, the architecture of a novel AVC algorithm is sketched out.

Published
2018
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35. Effects of exercise on different parameters in people living with HIV

Author

Zech, Philipp (Dipl.)

Subjects
Department Psychologie, ddc:150
Abstract

Hintergrund. Personen, die mit der chronischen Erkrankung HIV leben (PWH), müssen ihr Leben lang die sog. antiretrovirale Therapie (ART) einnehmen, um einen Ausbruch der Erkrankung in das Vollbild AIDS (Akquiriertes Immun-Defizienz-Syndrom) zu vermeiden. Gleichzeitig ist die ART und HIV selbst assoziiert mit dem Auftreten zusätzlicher Erkrankungen (Komorbiditäten) kardiovaskulärer oder psychologischer Natur. Die Prävalenz von Komorbiditäten und schlechter Lebensqualität ist im Vergleich zu HIV-negativen Personen deutlich höher. Methoden. Es wurden zwei Metaanalysen zu sportlicher Betätigung, PWH und (1) kardiovaskulären und (2) psychologischen Parametern sowie eine Querschnittsstudie (HIBES-Studie, HIV-Begleiterkrankungen und Sport) durchgeführt. Für die Auswertung der metaanalytischen Daten wurde der Review Manager 5.3, für die Auswertung der Daten der HIBES-Studie das Analyseprogramm „R“ verwendet. In den Metaanalysen wurden, neben den Hauptanalysen verschiedener Parameter, erstmals spezifische Subgruppenanalysen durchgeführt. Die HIBES-Studie untersuchte Unterschiede zwischen kumulativen (2-3 verschiedenen Sportarten pro Woche) und einfachen (eine Sportart pro Woche) Freizeitsport und analysiert die Zusammenhänge von Parametern des Freizeitsports (Trainingshäufigkeit, -Minuten und –Intensität), Komorbiditäten und der Lebensqualität. Ergebnisse. Ausdauer- und Krafttraining haben einen mittel-starken bis starken positiven Effekt auf die maximale Sauerstoffaufnahme (SMD= 0.66, p< .00001), den 6-Minuten-Walk-Test (6MWT) (SMD= 0.59, p= .02), die maximale Watt Zahl (SMD= 0.80, p= .009). Kein Effekt wurde bei der maximalen Herzfrequenz und dem systolischen sowie diastolischen Blutdruck gefunden. Subgruppenanalysen zu ≥3 Einheiten/Woche, ≥150 Min./Woche ergaben hohe Effektstärken in der maximalen Watt Zahl und 6MWT. Ausdauer- und Krafttraining zusammen mit Yoga haben einen starken Effekt auf Symptome der Depression (SMD= -0.84, p= .02) und Angststörungen (SMD= -1.23, p= .04). Die Subanalyse der Depression zu professioneller Supervision und sportlicher Betätigung wiesen einen sehr starken Effekt (SMD= -1.40, p= .03). Die HIBES-Studie wies ein sehr differenziertes Bild im Sportverhalten von PWH in Deutschland auf. 49% der Teilnehmer übten mehr als eine Sportart pro Woche aus. Es wurden keine Unterschiede zwischen kumuliertem (CTE) und einfachem Sport (STE) in der Lebensqualität gefunden. Die Freizeitsportparameter (Häufigkeiten/Woche, Minuten/Woche, Intensität/Woche) waren in der CTE-Gruppe deutlich höher als in der STE-Gruppe. Trainingsminuten und die -Intensität zeigten beim Vorhandensein einer Komorbidität einen großen Zusammenhang mit der Lebensqualität. Die Minuten und die Intensität des durchgeführten Sportes zeigten einen prädiktiven Zusammenhang mit der Lebensqualität. Konklusion: Sportliche Betätigung verbessert die maximale Sauerstoffaufnahme und Symptome der Depression und Angststörungen. Die Aussagekraft der Subanalysen ist aufgrund der geringen Studienzahl, vorsichtig zu interpretieren. Erhöhte Trainingsparameter finden sich eher bei PWH, die mehr als eine Sportart pro Woche treiben. Daher kann kumulierter Sport als mediierender Faktor zur Steigerung der Lebensqualität interpretiert werden; zumindest bei PWH mit einer psychologischen Komorbidität.

Published
2021

36. Life is swell - exposure to the beach, effects on well-being and HR implications

Author

Zech, Philipp and Sim, Samantha

Subjects
Wellbeing, Restoration, Blue space, HR-intervention, Ciências Sociais::Economia e Gestão [Domínio/Área Científica]
Abstract

The following paper analyses the role of nature for the restoration of attention and well being of university students. Draw ing on theories of Attention Restoration, Cognition and Well being an integration of blue spaces asa HR intervention was proposed. Apre/post two group design was employed, in which the condition group was ledin their class break to a mindfulness walk along side the ocean, where as the control group walk edinan urban setting. A significant in crease of positive affect and de crease of a rousal was found.However, a significant in crease of cognitive performance was not found.

Published
2020

37. Exercise, Comorbidities, and Health-Related Quality of Life in People Living with HIV: The HIBES Cohort Study

Author

Zech, Philipp, Schuch, Felipe, Pérez-Chaparro, Camilo, Kangas, Maria, Rapp, Michael, and Heissel, Andreas

Subjects
Adult, Male, lcsh:R, lcsh:Medicine, HIV, HIV Infections, Middle Aged, Article, Cohort Studies, comorbidity, Cross-Sectional Studies, exercise intensity, quality of life, Humans, Female, Exercise
Abstract

(1) Background: People with HIV (PWH) may perform more than one type of exercise cumulatively. The objective of this study is to investigate recreational exercise and its association with health-related quality of life (HRQOL) and comorbidities in relation to potential covariates. (2) Methods: The HIBES study (HIV-Begleiterkrankungen-Sport) is a cross-sectional study for people with HIV. The differences between non-exercisers versus exercisers (cumulated vs. single type of exercises) were investigated using regression models based on 454 participants. (3) Results: Exercisers showed a higher HRQOL score compared to non-exercisers (Wilcox r = 0.2 to 0.239). Psychological disorders were identified as the main covariate. Participants performing exercise cumulatively showed higher scores in duration, frequency, and intensity when compared to participants performing only one type of exercise. The mental health summary score was higher for the cumulated and single type of exercise if a psychological disorder existed. Duration and intensity were associated with an increase of HRQOL, whilst a stronger association between psychological disorders and exercise variables were evident. Exercise duration (minutes) showed a significant effect on QOL (standardized beta = 0.1) and for participants with psychological disorders (standardized beta = 0.3), respectively. (4) Conclusions: Psychological disorders and other covariates have a prominent effect on HRQOL and its association with exercise. For PWH with a psychological disorder, a stronger relationship between HRQOL with exercise duration and intensity emerged. However, differentiation of high-HRQOL individuals warrants further investigation by considering additional factors., Postprints der Universität Potsdam : Humanwissenschaftliche Reihe, 661

Published
2020

38. Exercise, Comorbidities, and Health-Related Quality of Life in People Living with HIV

Author

Zech, Philipp, Schuch, Felipe, Pérez-Chaparro, Camilo, Kangas, Maria, Rapp, Michael Armin (Prof. Dr. Dr.), and Heissel, Andreas (Dr.)

Subjects
ddc:690, Department Sport- und Gesundheitswissenschaften, ddc:610
Abstract

(1) Background: People with HIV (PWH) may perform more than one type of exercise cumulatively. The objective of this study is to investigate recreational exercise and its association with health-related quality of life (HRQOL) and comorbidities in relation to potential covariates. (2) Methods: The HIBES study (HIV-Begleiterkrankungen-Sport) is a cross-sectional study for people with HIV. The differences between non-exercisers versus exercisers (cumulated vs. single type of exercises) were investigated using regression models based on 454 participants. (3) Results: Exercisers showed a higher HRQOL score compared to non-exercisers (Wilcox r = 0.2 to 0.239). Psychological disorders were identified as the main covariate. Participants performing exercise cumulatively showed higher scores in duration, frequency, and intensity when compared to participants performing only one type of exercise. The mental health summary score was higher for the cumulated and single type of exercise if a psychological disorder existed. Duration and intensity were associated with an increase of HRQOL, whilst a stronger association between psychological disorders and exercise variables were evident. Exercise duration (minutes) showed a significant effect on QOL (standardized beta = 0.1) and for participants with psychological disorders (standardized beta = 0.3), respectively. (4) Conclusions: Psychological disorders and other covariates have a prominent effect on HRQOL and its association with exercise. For PWH with a psychological disorder, a stronger relationship between HRQOL with exercise duration and intensity emerged. However, differentiation of high-HRQOL individuals warrants further investigation by considering additional factors.

Published
2020

43. Effects of exercise on depression and anxiety in persons living with HIV: A meta-analysis

Author

Heissel, Andreas (Dr.), Zech, Philipp, Rapp, Michael Armin, Schuch, Felipe B., Lawrence, Jimmy B., Kangas, Maria, and Heinzel, Stephan

Subjects
Department Psychologie, ddc:610
Abstract

Objective: The purpose of this systematic review and meta-analysis was to examine the effects of exercise on depression and anxiety in people living with HIV (PLWH), and to evaluate, through subgroup analysis, the effects of exercise type, frequency, supervision by exercise professionals, study quality, and control group conditions on these outcomes. Method: A literature search was conducted through four electronic databases from inception to February 2019. Considered for inclusion were randomized controlled trials (RCTs) investigating exercise interventions and depression or anxiety as outcomes in people living with HIV (>= 18 years of age). Ten studies were included (n = 479 participants, 49.67% females at baseline), and the standardized mean difference (SMD) and heterogeneity were calculated using random-effect models. An additional pre-post meta-analysis was also conducted. Results: A large effect in favor of exercise when compared to controls was found for depression (SMD = -0.84, 95%CI = [-1.57, -0.11], p = 0.02) and anxiety (SMD = -1.23, 95%CI = [-2.42, 0.04], p = -0.04). Subgroup analyses for depression revealed large effects on depression for aerobic exercise only (SMD = -0.96, 95%CI = [-1.63, -0.30], p = 0.004), a frequency of >= 3 exercise sessions per week (SMD = -1.39, 95%CI = [-2.24, -0.54], p < 0.001), professionally supervised exercise (SMD = -1.40, 95%CI = [-2.46, -0.17], p = 0.03]), and high-quality studies (SMD = -1.31, 95%CI = [-2.46, -0.17], p = 0.02). Conclusion: Exercise seems to decrease depressive symptoms and anxiety in PLWH, but other larger and high-quality studies are needed to verify these effects.

Published
2019

44. Aktive Reduktion modulierter Zahneingriffsvibrationen von Planetengetrieben

Author

Zech, Philipp

Abstract

Der Forschungsbeitrag ist motiviert durch die vermehrte Anwendung von Planetengetrieben in neuen Technologien wie Getriebefan-Triebwerken. Das Ziel der Arbeit besteht darin, die Luft- und Körperschallemissionen von Planetengetrieben mithilfe eines Systems zur aktiven Schwingungsreduktion (ASR) zu reduzieren. Dies ermöglicht einerseits Komfortsteigerungen für Menschen durch Lärmreduktion und andererseits den Schutz empfindlicher Bauteile vor schädigenden Vibrationen. Eine Literaturrecherche macht Herausforderungen in Bezug auf Modellbildung, Regelalgorithmen und Aktorik durch den hohen Frequenzbereich des Zahneingriffs deutlich. ASR-Produkte nach dem aktuellen Stand der Technik funktionieren nur für deutlich tiefere Frequenzen. Zur messtechnischen Charakterisierung des Anregungsverhaltens von Planetengetrieben in der Leistungsklasse bis 10kW erfolgt der Aufbau eines Prüfstands. Dieser erlaubt die Ermittlungvon technischen und psychoakustischen Anforderungen an das zu entwickelnde ASR-System. Vier ausgewählte modellfreie Regelalgorithmen werden zur Kompensation modulierter Vibrationen aus Planetengetrieben weiterentwickelt. Eine einheitliche Simulationsumgebung erlaubt die Gegenüberstellung der Algorithmen. Der schmalbandig wirkende Simultaneous-Equations-Algorithmus wird ausgewählt. Eine Methode zur Auslegung von piezoelektrischen Inertialmassenaktoren (IMA) wird vorgestellt und angewendet. Zur Realisierung des ASR-Systems werden verschiedene Konzepte vorgeschlagen und diskutiert. Ein Konzept mit vier IMA in tangentialer Anordnung am Getriebegehäuse wird ausgelegt, konstruiert und am Prüfstand als Aktormodul aufgebaut. In Prüfstandsversuchen wird der entwickelte modellfreie Regelalgorithmus validiert. Er erzielt vergleichbare Regelgüten wie der modellbasierte FxLMSAlgorithmus, bei gleichzeitig größerer Robustheit gegenüber Regelstreckenänderungen. Das entwickelte Aktormodul ermöglicht signifikante Reduktionen verschiedener Regelgrößen wie Schalldruck, Beschleunigung oder Kraft. In den meisten untersuchten Konfigurationen ergeben sich deutliche Reduktionen der Regelgrößen, während andere Schwingungsgrößen verschlechtert werden. Die akustische Abstrahlung einer mit dem Getriebe verbundenen Platte kann auf Restamplituden von 18% verringert werden. Durch eine Reduktion von Lautheit und Tonhaltigkeit wird das Getriebegeräusch angenehmer wahrgenommen. Eine Diskussion von Potentialen und Aufwänden des ASR-Systems schließt die Arbeit ab.

Published
2019

45. Effects of Aerobic and Resistance Exercise on Cardiovascular Parameters for People Living With HIV

Author

Zech, Philipp, Perez-Chaparro, Camilo, Schuch, Felipe, Wolfarth, Bernd, Rapp, Michael Armin (Prof. Dr.), and Heissel, Andreas (Dr. phil.)

Subjects
Department Sport- und Gesundheitswissenschaften, ddc:610
Abstract

People living with HIV (PLWH) have limited exercise capacity because of anemia, neuromuscular disorders, and pulmonary limitations. We used a meta-analysis to examine the effect of aerobic and resistance exercise alone and in combination on cardiovascular parameters. Subgroup meta-analyses were conducted and long-term effects of exercise were investigated. A systematic literature search was conducted up to July/August 2017. The Physiotherapy Evidence Database-scale was used to rate quality and assess the risk of bias on the papers. Standardized mean differences (SMDs) were calculated to assess the effect of exercise. Posttreatment comparison between the exercise and control groups revealed moderate and large effect sizes in favor of the intervention group for VO2max (SMD50.66, p < .0001) and the 6-minute walk test (SMD = 1.11, p = .0001). Exercise had a positive effect on cardiovascular parameters in PLWH. Exercise can be a prevention factor for PLWH dealing with multiple comorbidities.

Published
2019

46. Recreational exercise is associated with lower prevalence of depression and anxiety and better quality of life in German people living with HIV.

Author

Pérez-Chaparro, Camilo, Kangas, Maria, Zech, Philipp, Schuch, Felipe B., Rapp, Michael, and Heissel, Andreas

Subjects
HIV-positive persons, CROSS-sectional method, RECREATION, EXERCISE, MENTAL depression, QUALITY of life, DESCRIPTIVE statistics, ANXIETY
Abstract

Sedentarism is a risk factor for depression and anxiety. People living with the human immunodeficiency virus (PLWH) have a higher prevalence of anxiety and depression compared to HIV-negative individuals. This cross-sectional study (n = 450, median age 44 (19–75), 7.3% females) evaluates the prevalence rates and prevalence ratio (PR) of anxiety and/or depression in PLWH associated with recreational exercise. A decreased likelihood of having anxiety (PR=0.57; 0.36-0.91; p = 0.01), depression (PR=0.41; 0.36-0.94; p=0.01), and comorbid anxiety and depression (PR = 0,43; 0.24-0.75; p=0.002) was found in exercising compared to non-exercising PLWH. Recreational exercise is associated with a lower risk for anxiety and/or depression. Further prospective studies are needed to provide insights on the direction of this association. [ABSTRACT FROM AUTHOR]

Published
2022
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47. Added value in mechanized tunnelling by intelligent systems.

Author

Flora, Matthias, Weiser, Torsten, Zech, Philipp, Fontana, Adrian, Ruepp, Anna, and Bergmeister, Konrad

Subjects
ARTIFICIAL intelligence, BUILDING sites, CONSTRUCTION projects, TECHNOLOGICAL progress, DIGITAL technology, CONSTRUCTION industry, TUNNEL design & construction, NETWORK neutrality
Abstract

Copyright of Geomechanik und Tunnelbau is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2021
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48. Effects of aerobic and resistance exercise alone or combined on strength and hormone outcomes for people living with HIV

Author

Pérez Chaparro, Camilo Germán Alberto, Zech, Philipp, Schuch, Felipe, Wolfarth, Bernd, Rapp, Michael Armin (Prof. Dr. med. Dr. phil.), and Heiβel, Andreas (Dr. phil.)

Subjects
ddc:610, Humanwissenschaftliche Fakultät
Abstract

Background: Infection with human immunodeficiency virus (HIV) affects muscle mass, altering independent activities of people living with HIV (PLWH). Resistance training alone (RT) or combined with aerobic exercise (AE) is linked to improved muscle mass and strength maintenance in PLWH. These exercise benefits have been the focus of different meta-analyses, although only a limited number of studies have been identified up to the year 2013/4. An up-to-date systematic review and meta-analysis concerning the effect of RT alone or combined with AE on strength parameters and hormones is of high value, since more and recent studies dealing with these types of exercise in PLWH have been published. Methods: Randomized controlled trials evaluating the effects of RT alone, AE alone or the combination of both (AERT) on PLWH was performed through five web-databases up to December 2017. Risk of bias and study quality was attained using the PEDro scale. Weighted mean difference (WMD) from baseline to post-intervention changes was calculated. The I2 statistics for heterogeneity was calculated. Results: Thirteen studies reported strength outcomes. Eight studies presented a low risk of bias. The overall change in upper body strength was 19.3 Kg (95% CI: 9.8±28.8, p< 0.001) after AERT and 17.5 Kg (95% CI: 16±19.1, p< 0.001) for RT. Lower body change was 29.4 Kg (95% CI: 18.1±40.8, p< 0.001) after RT and 10.2 Kg (95% CI: 6.7±13.8, p< 0.001) for AERT. Changes were higher after controlling for the risk of bias in upper and lower body strength and for supervised exercise in lower body strength. A significant change towards lower levels of IL-6 was found (-2.4 ng/dl (95% CI: -2.6, -2.1, p< 0.001). Conclusion: Both resistance training alone and combined with aerobic exercise showed a positive change when studies with low risk of bias and professional supervision were analyzed, improving upper and, more critically, lower body muscle strength. Also, this study found that exercise had a lowering effect on IL-6 levels in PLWH.

Published
2018

49. Physical activity protects from incident anxiety: A meta‐analysis of prospective cohort studies

Author

Schuch, Felipe B., primary, Stubbs, Brendon, additional, Meyer, Jacob, additional, Heissel, Andreas, additional, Zech, Philipp, additional, Vancampfort, Davy, additional, Rosenbaum, Simon, additional, Deenik, Jeroen, additional, Firth, Joseph, additional, Ward, Philip B., additional, Carvalho, Andre F., additional, and Hiles, Sarah A., additional

Published
2019
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