| 979401. |
- Papaioannou, Georgios, et al.
(författare)
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Proceedings of ISMA 2018 - International Conference on Noise and Vibration Engineering and USD 2018 - International Conference on Uncertainty in Structural Dynamics
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this work is to present a comparison of the main semi-active suspension systems for a passenger car using Logical Control. Their comparison will be conducted after having optimized them in respect with ride comfort and road holding. In this work, the semi active suspensions studied are comfort oriented and consist of (a) two versions of Skyhook control (SH-2 and SH-L, two states and linear approximation damper respectively), (b) the acceleration driven damper (ADD), (d) one version of the combination of Skyhook and ADD (SH-ADD) and (e) a second version implemented with the use of a sensor. Thus, a half car model, with a passenger and a seat, was excited by a random road profile of class C. The model was optimized using genetic algorithms (GA). This study, firstly, aims to highlight how the optimization of the vehicle model could lead to the best compromise between ride comfort and road holding, and secondly, the test of an alternative approach in the operational conditions of the control algorithms.
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| 979402. |
- Papaioannou, Georgios, et al.
(författare)
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Reducing Tyre Wear Emissions of Automated Articulated Vehicles through Trajectory Planning †
- 2024
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Ingår i: Sensors. - : Multidisciplinary Digital Publishing Institute (MDPI). - 1424-8220. ; 24:10
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Tidskriftsartikel (refereegranskat)abstract
- Effective emission control technologies and eco-friendly propulsion systems have been developed to decrease exhaust particle emissions. However, more work must be conducted on non-exhaust traffic-related sources such as tyre wear. The advent of automated vehicles (AVs) enables researchers and automotive manufacturers to consider ways to further decrease tyre wear, as vehicles will be controlled by the system rather than by the driver. In this direction, this work presents the formulation of an optimal control problem for the trajectory optimisation of automated articulated vehicles for tyre wear minimisation. The optimum velocity profile is sought for a predefined road path from a specific starting point to a final one to minimise tyre wear in fixed time cases. Specific boundaries and constraints are applied to the problem to ensure the vehicle’s stability and the feasibility of the solution. According to the results, a small increase in the journey time leads to a significant decrease in the mass loss due to tyre wear. The employment of articulated vehicles with low powertrain capabilities leads to greater tyre wear, while excessive increases in powertrain capabilities are not required. The conclusions pave the way for AV researchers and manufacturers to consider tyre wear in their control modules and come closer to the zero-emission goal.
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| 979403. |
- Papaioannou, Georgios, et al.
(författare)
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Skyhook control strategy for vehicle suspensions based on the distribution of the operational conditions
- 2021
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part P. - : SAGE Publications. - 1754-3371 .- 0954-4070 .- 2041-2991.
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Tidskriftsartikel (refereegranskat)abstract
- In this work, a novel distribution-based control strategy of semi-active vehicle suspensions is tested under different conditions. The novelty lies in the use of an appropriate threshold in the operational condition of the control algorithm, with which the operational conditions severity is quantified and the state of the damper is controlled according to the magnitude of the operational conditions and not their sign. The value of the threshold depends on the vibrations induced to the sprung mass by the road profile. In order to be evaluated, the operational conditions of the algorithm are fitted to a t-student distribution. The cumulative distribution function of this distribution is used in order to decrease the fraction of the sample operating with the damper’s stiff state. The strategy is applied to traditional SH control algorithms and is tested using a quarter car model excited by different road excitations. A sensitivity analysis for various threshold values is performed, investigating the impact of adopting the cumulative distribution functioned (CDF) controller to various performance metrics. The results illustrate an increase of up to 13% in the ride comfort of the passengers and increase of 6% in the road holding of the vehicle. Both are achieved by minimizing the switches of the damping ratio up to 80%
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| 979404. |
- Papaioannou, Konstantinos-Georgios, 1983-, et al.
(författare)
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Benefits of Fruit and Vegetable Consumption on Prevalence of Metabolic Syndrome Are Independent of Physical Activity Behaviors in Older Adults
- 2022
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Ingår i: Nutrients. - : MDPI. - 2072-6643. ; 14:2
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Tidskriftsartikel (refereegranskat)abstract
- Although consumption of fruits and vegetables (FV) is suggested to reduce metabolic risk, there is a paucity of studies taking advantage of objectively assessed physical activity (PA) behaviors when exploring links between FV intake and metabolic syndrome (MetS) in older adults. The aim of the present study was to determine the relationship between FV intake and MetS prevalence in a population of older community-dwelling adults, while considering time spent being sedentary and health-enhancing PA. Prevalence of MetS was determined in a population of 93 men and 152 women (age: 65-70 years). FV intake was determined by self-report and PA behaviors (time spent in moderate-to-vigorous PA (MVPA) and in sedentary) were assessed by accelerometry. Likelihood of having MetS by FV intake was determined using logistic regression with stepwise backward elimination including age, sex, educational level, total energy intake, adherence to MVPA guideline and total sedentary time as covariates. A main finding was that lower FV intakes were significantly related to higher prevalence of MetS (odds ratio [OR]: 1.23; 95% confidence interval [CI]: 1.03-1.47) after considering potential influences by covariates. Additionally, we found that lower intake of vegetables but not fruits was significantly related to higher prevalence of MetS (OR: 1.47; 95%CI: 1.04-2.07). In conclusion, lower intakes of FV in general, and of vegetables in particular, significantly increased likelihood of MetS, regardless of time spent sedentary and adherence to the MVPA guideline. From a public health perspective, our findings emphasize adequate intakes of FV as an independent contributor to metabolic health status in older adults.
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| 979405. |
- Papaioannou, Konstantinos Georgios, 1983-, et al.
(författare)
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Consumption of Vegetables Is Associated with Systemic Inflammation in Older Adults
- 2022
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Ingår i: Nutrients. - Basel : MDPI. - 2072-6643. ; 14:9
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Tidskriftsartikel (refereegranskat)abstract
- It is hypothesized that healthy diets rich in fruits and vegetables (FV) can modulate the inflammatory status in older adults. However, to determine the actual impact of FV on inflammatory status, adiposity level and objectively assessed physical activity (PA) behaviors need to be considered. The aim of the present study was to explore associations between FV intake and biomarkers of systemic inflammation in older adults. Based on a sample of 233 older adults (65-70 years old), the following inflammatory biomarkers were assessed: C-reactive protein (CRP), fibrinogen, interleukin-6 (IL-6), IL-10, IL-18, and monocyte chemoattractant protein-1 (MCP-1). FV intake was assessed by self-report, and PA behaviors encompassing time spent sedentary and in moderate-to-vigorous PA (MVPA) were determined using accelerometers. Associations between FV intake and inflammatory biomarkers were analyzed using stepwise linear regression models while adjusting for several covariates, including health-related food groups, adherence to the MVPA guidelines, total sedentary time, and waist circumference. While no significant associations were observed for the total FV intake, the vegetable intake was inversely associated with levels of IL6 (β = -0.15; p < 0.05). In contrast, fruit intake was not associated with any inflammatory biomarker. In conclusion, our findings indicate beneficial associations between vegetable intake and levels of a pro-inflammatory biomarker in older adults, which strengthens public health efforts to promote vegetable-rich diets in older adults to mitigate age-related systemic inflammation.
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| 979406. |
- Papaioannou, Konstantinos-Georgios, 1983-
(författare)
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Diet and physical activity behaviors for healthy aging
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The process of aging is characterized by physiological changes in various body systems and biological functions, that affect health and functional capacity. Adopting healthy lifestyle behaviors could be an effective, accessible, and lowcost strategy to delay age-related functional changes. Dietary habits, including both patterns and amounts of specific food items, and physical activity (PA)are two lifestyle factors that may have an impact on several age-related health aspects. The overall aim of this thesis was to determine the links between diet, physical activity behaviors, and biological markers of healthy aging, including muscle health, metabolic health, and systemic inflammation in older adults.The findings of the present work collectively highlight the role of diet and physical activity behaviors on biological markers of healthy aging in older adults. Daily amounts of sedentary time were detrimentally associated with the systemic inflammatory environment, with sex-specific alterations in proand anti-inflammatory biomarkers. In term of dietary habits, higher intakes of vegetables were associated with lower levels of the pro-inflammatory biomarker IL-6 in older adults, regardless of intakes of other health-related food groups, physical activity behaviors, and adiposity level. Moreover, lower intakes of fruit and vegetables (FV) in general, and of vegetables in particular, increased the likelihood of having metabolic syndrome (MetS) in older adults, which was evident even after considering time spent in sedentary behavior and adherence to the moderate-to-vigorous physical activity (MVPA) guideline. Finally, healthy eating was beneficially associated with lower sarcopenia risk in physically active older men and women, even when engagement in musclestrengthening activities and adherence to guidelines for protein intake were considered. Overall, the present thesis demonstrates the detrimental impact of excessive amounts of sedentary time on markers of systemic inflammation and highlights the beneficial effects of healthy eating on biological determinants of healthy aging regardless of the potential confounding effects of physical activity behaviors.
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| 979407. |
- Papaioannou, Konstantinos Georgios, 1983-, et al.
(författare)
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Healthy Diets Rich in Vegetables and Systemic Inflammation in Older Adults
- 2022
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Ingår i: Biology and Life Sciences Forum. - : MDPI. - 2673-9976. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to explore links between dietary habits and biomarkers of systemic inflammation in older adults. In a sample of 233 community-dwelling older adults (65–70 years), dietary habits were assessed by a food-frequency questionnaire. Physical activity and sedentary time were assessed using accelerometry. Inflammatory biomarkers were assessed from blood samples. The results showed that intake of vegetables was inversely related to levels of systemic inflammation (p < 0.05), independently of physical activity level. The present study strengthens public health efforts to promote vegetable-rich diets in older adults to mitigate age-related systemic inflammation.
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| 979408. |
- Papaioannou, Stylianos, et al.
(författare)
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Advantages, Pitfalls, and Developments of All Optical Interrogation Strategies of Microcircuits in vivo
- 2022
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Ingår i: Frontiers in Neuroscience. - : Frontiers Media S.A.. - 1662-4548 .- 1662-453X. ; 16
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Forskningsöversikt (refereegranskat)abstract
- The holy grail for every neurophysiologist is to conclude a causal relationship between an elementary behaviour and the function of a specific brain area or circuit. Our effort to map elementary behaviours to specific brain loci and to further manipulate neural activity while observing the alterations in behaviour is in essence the goal for neuroscientists. Recent advancements in the area of experimental brain imaging in the form of longer wavelength near infrared (NIR) pulsed lasers with the development of highly efficient optogenetic actuators and reporters of neural activity, has endowed us with unprecedented resolution in spatiotemporal precision both in imaging neural activity as well as manipulating it with multiphoton microscopy. This readily available toolbox has introduced a so called all-optical physiology and interrogation of circuits and has opened new horizons when it comes to precisely, fast and non-invasively map and manipulate anatomically, molecularly or functionally identified mesoscopic brain circuits. The purpose of this review is to describe the advantages and possible pitfalls of all-optical approaches in system neuroscience, where by all-optical we mean use of multiphoton microscopy to image the functional response of neuron(s) in the network so to attain flexible choice of the cells to be also optogenetically photostimulated by holography, in absence of electrophysiology. Spatio-temporal constraints will be compared toward the classical reference of electrophysiology methods. When appropriate, in relation to current limitations of current optical approaches, we will make reference to latest works aimed to overcome these limitations, in order to highlight the most recent developments. We will also provide examples of types of experiments uniquely approachable all-optically. Finally, although mechanically non-invasive, all-optical electrophysiology exhibits potential off-target effects which can ambiguate and complicate the interpretation of the results. In summary, this review is an effort to exemplify how an all-optical experiment can be designed, conducted and interpreted from the point of view of the integrative neurophysiologist.
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| 979409. |
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| 979410. |
- Papaioannou, Stylianos, et al.
(författare)
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Goal-dependent tuning of muscle spindle receptors during movement preparation
- 2021
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 7:9
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Tidskriftsartikel (refereegranskat)abstract
- Voluntary movements are believed to undergo preparation before they are executed. Preparatory activity can benefit reaction time and the quality of planned movements, but the neural mechanisms at work during preparation are unclear. For example, there are no overt changes in muscle force during preparation. Here, using an instructed-delay manual task, we demonstrate a decrease in human muscle afferent activity (primary spindles) when preparing to reach targets in directions associated with stretch of the spindle-bearing muscle. This goal-dependent modulation of proprioceptors began early after target onset but was markedly stronger at the latter parts of the preparatory period. Moreover, whole-arm perturbations during reach preparation revealed a modulation of stretch reflex gains (shoulder and upper arm muscles) that reflected the observed changes in spindle activity. We suggest that one function of central preparatory activity is to tune muscle stiffness according to task goals via the independent control of muscle spindle sensors.
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