Auto-tuning of PID Controllers for Robotic Manipulators Using PSO and MOPSO

This work proposes two approaches to automatic tuning of PID position controllers based on different global optimization strategies. The chosen optimization algorithms are PSO and MOPSO, i. e. the problem is handled as a single objective problem in the first implementation and as a multiobjective problem in the second one. The auto-tuning is performed without assuming any previous knowledge of the robot dynamics. The objective functions are evaluated depending on real movements of the robot. Therefore, constraints guaranteeing safe and stable robot motion are necessary, namely: a maximum joint torque constraint, a maximum position error constraint and an oscillation constraint. Because of the practical nature of the problem in hand, constraints must be observed online. This requires adaptation of the optimization algorithm for reliable observance of the constraints without affecting the convergence rate of the objective function. Finally, Experimental results of a 3-DOF robot for different trajectories and with different settings show the validity of the two approaches and demonstrate the advantages and disadvantages of every method

Beneficial effects of an intergenerational exercise intervention on health-related physical and psychosocial outcomes in Swiss preschool children and residential seniors: a clinical trial

Background. Intergenerational exercise possesses the potential to becoming an innovative strategy for promoting physical activity in seniors and children. Although this approach has gained attraction within the last decade, controlled trials on physical and psychosocial effects have not been performed yet. Methods. Sixty-eight healthy preschool children (age: 4.9 y (SD 0.7)) and 47 residential seniors (age: 81.7 y (7.1)) participated in this five-armed intervention study. All participants were assigned to either an intergenerational (IG), peer (PG) or a control group (CON). Children were tested on gross motor skills (TGMD-2), jump performance and handgrip strength. Social-emotional skills questionnaires (KOMPIK) were assessed by kindergarten teachers. Seniors performed the Short Physical Performance Battery (SPPB), including gait speed. Arterial stiffness parameters were also examined. Questionnaires assessing psychosocial wellbeing were filled in with staff. IG and PG received one comparable exercise session a week lasting 45 minutes for 25-weeks. CON received no intervention. Measurements were performed before and after the intervention. Results. In children: IG improved all measured physical parameters. When adjusted for baseline values, large effects were observed in favor of IG compared to CON in TGMD-2 (Cohen's d=0:78 [0.33;1.24]) and in handgrip strength (d=1.07 [0.63;1.51]). No relevant differences were found in KOMPIK between groups (-0.38<d≤0.14). In seniors: IG showed moderate to very large improvements in all main physical performance (0.61<d≤2.53) and psychosocial parameters (0.89<d≤1.20) compared to CON. Conclusion. IG children showed large benefits in motor skills compared to CON while IG seniors benefit especially in psychosocial wellbeing and functional mobility necessary for everyday life. Intergenerational exercise is comparable and in certain dimensions superior to peer group exercise and a promising strategy to integratively improve mental health as well as physical fitness in preschool children and residential seniors

Femtosecond laser inscribed advanced calibration phantom for optical coherence tomography (OCT)

Optical coherence tomography (OCT) has developed rapidly and is widely used in different fields such as biomedicine and optometry. The characterization and calibration of OCT systems is essential when testing the system and during normal use to ensure that there is no misalignment or distortion that could affect clinical decisions. Imaging distortion is a significant challenge for OCT systems when viewing through non-planar surfaces. Here we present a new multi-purpose plano-convex OCT phantom which is designed to be used for OCT characterization and calibration as well as to validate the post-processing algorithm for the imaging distortion of the OCT systems. A femtosecond laser direct writing technique is used to fabricate this phantom which consists of a landmark layer with radial lines at a 45-degree angular spacing inscribed at 50μm in apparent depth (AD) underneath the planar surface. Below that there are a further 8 layers of a spherical inscription pattern which has a 150μm (in AD) separation between each layer. The first spherical layer is located at 150μm (in AD) underneath the planar surface. Due to the laser power loss when travelling through the deeper layer, an increased power is applied to the deeper layers. The spherical pattern overcomes orientation issues seen with existing calibration phantoms. The landmark layer is applied so that it can easily tell the exact location when scanning which will also benefit the image distortion correction process

A comparative analysis of formulations for the Hamiltonian p-Median Problem

Tese de Mestrado, Estatística e Investigação Operacional , 2022, Universidade de Lisboa, Faculdade de CiênciasIn this dissertation we study the Hamiltonian p-Median Problem, a combinatorial optimization problem in which, given an undirected graph G = (V, E) and a cost for each edge, the objective is to find the cheapest way to partition the set of nodes into p subsets with each subset being connected by a single cycle. This is a problem which may therefore be seen as a generalization of the Travelling Salesman Problem (TSP). When working with MILP models for the TSP, sets of constraints to prevent feasible solutions with more than one cycle are added to an assignment formulation. Similarly, when working with such models for the HpMP, sets of constraints to prevent feasible solutions with more than p cycles can also be added to an assignment formulation, and these are often very similar to sets of constraints already used in models for the TSP, albeit with some modifications. However, these sets are not sufficient to guarantee every feasible solution has exactly p cycles, since it may have fewer than p cycles. To this end, additional sets of constraints for preventing solutions with less than p cycles may be introduced, and these will be the focal point of this work. The work begins with a brief introduction to the problem and some literature review. After that, several compact formulations for this problem are presented. The presentation of these models will be split into three parts. In the first part, a model upon which all other models are built is presented. The second part focuses on a model used to prevent solutions with more than p cycles, while the third part focuses on two models used to prevent solutions with less than p cycles (in which nodes are assigned to depots or cycles), accompanied by some valid inequalities. Finally, some of the models presented in this work are tested and the results and possibilities for future work are discussed

Microbial Growth Dynamics in Minced Meat Enriched with Plant Powders

Plant powders with antimicrobial properties can be used in food manufacturing and must comply with the demands of consumers regarding microbiological safety, nutritional value, and sensory properties of foods. The present study aimed to assess the microbial growth inhibitory ability of different plant powders, including by-products of horticultural primary processing (e.g., pomace) in raw and cooked minced pork. The total counts of aerobic mesophilic bacteria, pseudomonads, yeasts, and moulds were studied to assess the microbial growth dynamics in meat samples. Additionally, for the plant powders, which were able to suppress the microbial growth in a total counts dynamics study, the growth potential of Listeria monocytogenes in ready-to-eat (RTE) minced meat samples was estimated by challenge testing. The results showed that the most effective combinations of plant powders in raw minced pork, in relation to the total counts of microorganisms, were 3% apple+1% onion+2% blackcurrant berries (Apple+On+BCber); 3% apple+1% garlic+2% tomato (Apple+Ga+Tom); and 3% apple+2% tomato+1% rhubarb petioles (Apple+Tom+Rhub). However, challenge tests revealed that some plant powders were unable to inhibit the growth of L. monocytogenes. The lowest L. monocytogenes growth potential (δ = 2.74 log cfu/g) was determined for cooked minced pork samples enriched with 2% rhubarb petioles, followed by Apple+On+BCber (δ = 3.63 log cfu/g) and Apple+Tom+Rhub (δ = 3.74 log cfu/g). In minced pork samples without plant additives, the L. monocytogenes growth potential was 7.30 log cfu/g. In conclusion, blends of plant powders may have good potential for developing meat products with acceptable microbiological quality

Noncanonical Hydrogen Bonding In Nucleic Acids. Benchmark Evaluation Of Key Base-phosphate Interactions In Folded Rna Molecules Using Quantum-chemical Calculations And Molecular Dynamics Simulations

RNA molecules are stabilized by a wide range of non canonical interactions that are not present in DNA. Among them, the recently classified base phosphate (BPh) interactions belong to the most important ones. Twelve percent of nucleotides in the ribosomal crystal structures are involved in BPh interactions. BPh interactions are highly conserved and provide major constraints on RNA sequence evolution. Here we provide assessment of the energetics of BPh interactions using MP2 computations extrapolated to the complete basis set of atomic orbitals and corrected for higher-order electron correlation effects. The reference computations are compared with DFT-D and DFT-D3 approaches, the SAPT method, and the molecular mechanics force field. The computations, besides providing the basic benchmark for the BPh interactions, allow some refinements of the original classification, including identification of some potential doubly bonded BPh patterns. The reference computations are followed by analysis of some larger RNA fragments that consider the context of the BPh interactions. The computations demonstrate the complexity of interaction patterns utilizing the BPh interactions in real RNA structures. The BPh interactions are often involved in intricate interaction networks. We studied BPh interactions of protonated adenine that can contribute to catalysis of hairpin ribozyme, the key BPh interaction in the S-turn motif of the sarcin ricin loop, which may predetermine the S-turn topology and complex BPh patterns-from the glmS riboswitch. Finally, the structural stability of BPh interactions in explicit solvent molecular dynamics simulations is assessed. The simulations well preserve key BPh interactions and allow dissection of structurally/functionally important water-meditated BPh bridges, which could not be considered in earlier bioinformatics classification of BPh interactions

Generations on the move: intergenerational exercise and health promotion

Background In light of demographic and societal changes as well as increasing inactivity within the last decades, the intergenerational exercise setting has been gaining attraction as it possesses the potential to becoming an innovative strategy to promote physical activity in children and seniors. Nevertheless, the effects of such intergenerational exercise programs on physical and psychosocial health have not been examined yet. Aim This PhD project aimed to examine the effects of an intergenerational exercise intervention on physical and psychosocial health-outcomes in preschool children and residential seniors. In this regard, the effects of the exercise setting were compared to peer-group exercise and control conditions in both generations. Furthermore, specific research on the relationship between various health outcomes and physical activity in children and seniors were evaluated. Methods The Generations on the Move Study is a five-armed controlled trial with a 25-week physical exercise training intervention and pre- and post-intervention assessments. Six kindergartens with 68 healthy children and five senior homes with 47 residential seniors from Basel-Stadt and surroundings participated in this study. The kindergartens and senior homes were assigned either to an intergenerational (IG), a peer (PG) or a control group (CON). Children were assessed in gross motor skills (TGMD-2), jump performance, handgrip strength as well as micro- and macrovascular health. Social-emotional skills were assessed by kindergarten teachers with a questionnaire (KOMPIK). Seniors performed the Short Physical Performance Battery (SPPB), including gait speed. Central hemodynamics as well as arterial stiffness were also examined. Questionnaires assessing psychosocial wellbeing (SF-36; FES; AQoL-8) were filled in with staff. IG and PG received one comparable exercise session a week lasting 45 minutes for 25 weeks. The training sessions were conducted in the respective institutions, whereby IG children were accompanied to their partnering residence home. Both CON groups received no intervention and were asked to uphold daily habits. Measurements were performed before and after the intervention. Between group differences were calculated using linear regression models. Results Children: Our analyses show at least moderate improvements of IG over CON in most main physical performance parameters (0.45<d≤1.07) and no relevant differences in social-emotional skills (-0.12<d≤0.14). Compared to PG, IG showed moderate effects in gross motor skills (TGMD-2: d=0.58 [0.13;1.03]) and handgrip strength (d=0.66 [0.26;1.07]). Small effects for IG over PG were found in all social-emotional dimensions (0.25<d≤0.40). Seniors: Moderate to very large improvements in IG compared to CON were found in all physical performance parameters (0.76<d≤2.53) as well as in markers of cardiovascular health (0.35<d≤0.56). Small to large differences in favor of IG over CON are compatible with data in all questionnaires (SF-36: d=0.94 [0.28;1.59]; FES: d=0.89 [0.21;1.58]; AQoL-8: d=1.20 [0.62;1.79]). Data comparing IG to PG show compatibility with trivial to at least moderate effects in favor of IG in SPPB (d=0.45 [0.04;0.86]), single task gait speed (d=0.40; [0.05;0.74]) and blood pressure (0.58<d≤0.63). IG showed moderate effects in general health score (d=0.68 [0.07;1.29]) and small to moderate effects over PG in all AQoL-8 dimensions (0.23<d≤0.51) whereby data is compatible with small to large effects. Conclusion Children in the intergenerational group show largest improvements in motor skills while intergenerational seniors benefit especially in functional mobility necessary for everyday life and psychosocial wellbeing. The intergenerational exercise setting is comparable and in certain dimensions superior to peer-group training and is, therefore, a promising strategy to promote physical performance parameters essential for lifelong fitness and health in children while simultaneously challenging their social-emotional learning skills. The maintenance and, more importantly, the improvements in physical health in seniors are very promising insights, speaking in favor of this setting, especially in combination with the improvements in mental health and quality of life. Future fields of research should examine the underlying mechanisms, long-term effects as well as different populations of children and seniors

Growth and persistence of 17 annual medic (Medicago spp.) accessions on clay soils in central Queensland

Seventeen accessions of annual medics were evaluated on clay soil sites at Emerald, Theodore, Biloela and Mundubbera, central Queensland. Successful medics could have a role in both permanent and ley pastures. However, these are marginal areas for medics with winter (June-August) rainfalls of 80-100 mm. The accessions were selected on the basis of results in southern Queensland, a more favoured area for medics. There were 9 accessions of Medicago truncatula (barrel medic), 4 of M. scutellata (snail medic), 2 of M. polymorpha (burr medic) and 1 each of M. aculeata (keg medic) and M. orbicularis (button medic). Lucerne (M. sativa) cv. Trifecta was sown at 3 sites. All sites except Theodore were irrigated in the year of establishment (1993). The medic seedlings at Theodore died in 1993 and the trial was resown in 1994. Measurements were made of seed set in the first year and whenever it occurred in later years, seedling density in most years and yield when there was adequate growth. Selected measurements were made of soil seed reserves. Measurements ceased in 1998