Coordination and Control of Autonomous Mobile Robots Swarms by using Particle Swarm Optimization Algorithm and Consensus Theory

This thesis presents some different techniques designed to drive a swarm of robots in an a-priori unknown environment in order to move the group from a starting area to a final one avoiding obstacles. The presented techniques are based on two different theories used alone or in combination: Swarm Intelligence (SI) and Graph Theory. Both theories are based on the study of interactions between different entities (also called agents or units) in Multi- Agent Systems (MAS). The first one belongs to the Artificial Intelligence context and the second one to the Distributed Systems context. These theories, each one from its own point of view, exploit the emergent behaviour that comes from the interactive work of the entities, in order to achieve a common goal. The features of flexibility and adaptability of the swarm have been exploited with the aim to overcome and to minimize difficulties and problems that can affect one or more units of the group, having minimal impact to the whole group and to the common main target. Another aim of this work is to show the importance of the information shared between the units of the group, such as the communication topology, because it helps to maintain the environmental information, detected by each single agent, updated among the swarm. Swarm Intelligence has been applied to the presented technique, through the Particle Swarm Optimization algorithm (PSO), taking advantage of its features as a navigation system. The Graph Theory has been applied by exploiting Consensus and the application of the agreement protocol with the aim to maintain the units in a desired and controlled formation. This approach has been followed in order to conserve the power of PSO and to control part of its random behaviour with a distributed control algorithm like Consensus.

The postantibiotic effect in the treatment of experimental meningitis caused by Streptococcus pneumoniae in rabbits

The relevance of a postantibiotic effect in the treatment of pneumococcal meningitis was evaluated in a rabbit model. After administration of a single intravenous bolus of ampicillin at various dosages, such an effect was observed in all animals. The duration of this effect in vivo (2.5-18 hr) was consistently longer than that in vitro (1-4.3 hr); however, in rabbits the postantibiotic effect was eliminated by the administration of intravenous plus intracisternal beta-lactamase. In an assessment of the potential therapeutic benefit of the postantibiotic effect, the efficacy to two regimens of treatment with different intervals between doses was compared. One group of animals received ampicillin every 4 hr and another every 12 hr. With sufficiently high doses, drug concentrations in cerebrospinal fluid exceeded the minimal bactericidal concentration for most of the 4-hr interval but for only about one-third of the 12-hr interval. The rate of cure was similar for the two regimens and approximated 100% when peak drug concentrations in cerebrospinal fluid exceeded the minimal bactericidal concentration by at least 10-fold.

Comparison of a new, minimally invasive strabismus surgery technique with the usual limbal approach for rectus muscle recession and plication

AIM: To present a novel, minimally invasive strabismus surgery (MISS) technique for rectus muscle operations. METHODS: In this prospective study with a non-concurrent, retrospective comparison group, the first 20 consecutive patients treated with MISS were matched by age, diagnosis and muscles operated on, with 20 patients with a limbal opening operated on by the same surgeon at Kantonsspital, St Gallen, Switzerland. A total of 39 muscles were operated on. MISS is performed by applying two small radial cuts along the superior and inferior muscle margin. After muscle separation from surrounding tissue, a recession or plication is performed through the resulting tunnel. Alignment, binocular single vision, variations in vision, refraction, and number and types of complications during the first 6 postoperative months were registered. RESULTS: Visual acuity decreased at postoperative day 1 in both groups. The decrease was less pronounced in the group operated on with MISS (difference of decrease 0.14 logMAR, p<0.001). An abnormal lid swelling at day 1 was more frequent in the control group (21%, 95% confidence interval (CI) 9% to 41%, 5/24 v 0%, 95% CI 0 to 13%, 0/25, p<0.05). No significant difference was found for final alignment, binocular single vision, other visual acuities, refractive changes or complications (allergic reactions, dellen formation, abnormal conjuctival findings). A conversion to a limbal opening was necessary in 5% (95% CI 2% to 17%, 2/39) of muscles. CONCLUSIONS: This study shows that this new, small-incision, minimal dissection technique is feasible. The MISS technique seems to be superior in the direct postoperative period as better visual acuities and less lid swelling were observed. Long-term results did not differ in the two groups.

Class II treatment by extraction of maxillary first molars or Herbst appliance: dentoskeletal and soft tissue effects in comparison

AIM To compare dentoskeletal and soft tissue treatment effects of two alternative Class II division 1 treatment modalities (maxillary first permanent molar extraction versus Herbst appliance). METHODS One-hundred-fifty-four Class II division 1 patients that had either been treated with extractions of the upper first molars and a lightwire multibracket (MB) appliance (n = 79; 38 girls, 41 boys) or non-extraction by means of a Herbst-MB appliance (n = 75; 35 girls, 40 boys). The groups were matched on age and sex. The average age at the start of treatment was 12.7 years for the extraction and for 13.0 years for the Herbst group. Pretreatment (T1) and posttreatment (T2) lateral cephalograms were retrospectively analyzed using a standard cephalometric analysis and the sagittal occlusal analysis according to Pancherz. RESULTS The SNA decrease was 1.10° (p = 0.001) more pronounced in the extraction group, the SNB angle increased 1.49° more in the Herbst group (p = 0.000). In the extraction group, a decrease in SNB angle (0.49°) was observed. The soft tissue profile convexity (N-Sn-Pog) decreased in both groups, which was 0.78° more (n. s.) pronounced in the Herbst group. The nasolabial angle increased significantly more (+ 2.33°, p = 0.025) in the extraction group. The mechanism of overjet correction in the extraction group was predominantly dental (65% dental and 35% skeletal changes), while in the Herbst group it was predominantly skeletal (58% skeletal and 42% dental changes) in origin. CONCLUSION Both treatment methods were successful and led to a correction of the Class II division 1 malocclusion. Whereas for upper first molar extraction treatment more dental and maxillary effects can be expected, in case of Herbst treatment skeletal and mandibular effects prevail.

Nonlinear quasi-static finite element simulations predict in vitro strength of human proximal femora assessed in a dynamic sideways fall setup

Osteoporotic proximal femur fractures are caused by low energy trauma, typically when falling on the hip from standing height. Finite element simulations, widely used to predict the fracture load of femora in fall, usually include neither mass-related inertial effects, nor the viscous part of bone's material behavior. The aim of this study was to elucidate if quasi-static non-linear homogenized finite element analyses can predict in vitro mechanical properties of proximal femora assessed in dynamic drop tower experiments. The case-specific numerical models of thirteen femora predicted the strength (R2=0.84, SEE=540 N, 16.2%), stiffness (R2=0.82, SEE=233 N/mm, 18.0%) and fracture energy (R2=0.72, SEE=3.85 J, 39.6%); and provided fair qualitative matches with the fracture patterns. The influence of material anisotropy was negligible for all predictions. These results suggest that quasi-static homogenized finite element analysis may be used to predict mechanical properties of proximal femora in the dynamic sideways fall situation.

New non-reorientational optical nonlinear effect in MBBA

A new effect producing self-focusing of light in a nematic MBBA film is reported. This effect produces a static diffraction pattern composed of circular rings which is different from the ones arising from self-focusing previously reported. The influence of the cell thickness, the optical intensity, and the wavelength is studied. Once the nematic is distorted by a láser beam, the effect produced in other light beam passing through the modified región is independent of its polarization. This isotropic behavior shows that a molecular reorientation has not been produced. The origin of this effect seems to be the same of that of the effect which produces a randomly oscillating diffraction pattern previously reported by our group. Some possible causes such as thermal indexing, convective instabilities and self-induced transparency are discussed.

Using O2 to probe membrane immersion depth by 19F NMR

A fluorinated detergent, CF3(CF2)5C2H4-O-maltose, was reconstituted into a lipid bilayer model membrane system to demonstrate the feasibility of determining solvent accessibility and membrane immersion depth of each fluorinated group by 19F NMR. Apolar oxygen, which is known to partition with an increasing concentration gradient toward the hydrophobic membrane interior, exhibits a range of paramagnetic relaxation effects on 19F nuclei, depending on its depth in the membrane. This effect, which is predominately associated with spin-lattice relaxation rates (R1) and chemical shifts, can be amplified greatly with minimal line broadening by increasing the partial pressure of O2 at least 100-fold (i.e., PO2 greater than 20 bar). The differences of longitudinal relaxation rates at 20 bar of oxygen pressure to those under ambient pressure (R120bar − R10) are largest for those fluorine groups expected to be most deeply buried in the membrane bilayer. This result contrasts with the reverse trend, which is observed on addition of a membrane surface-associated paramagnetic species, 4-(N,N-dimethyl-N-hexadecyl) ammonium-2,2,6,6-tetramethylpiperidine-1-oxyl iodide (CAT-16) at ambient pressures. Thus, differential relaxation rates may be observed in 19F-labeled membrane-associated molecules resulting from the addition of apolar oxygen under high pressure. The results demonstrate that the degree of solvent accessibility and membrane immersion depth of specific fluorinated species in membrane-associated macromolecules can be probed by 19F NMR.

Blood glucose self-monitoring in non-insulin-treated type 2 diabetes:a qualitative study of patients' perspectives

Background: Self-monitoring of blood glucose is controversial in the management of type 2 diabetes. Some research suggests that self-monitoring improves glycaemic control, whereas other research is sceptical about its value for people with type 2 diabetes who are not on insulin. Although blood glucose meters are widely available and used by this group, patients' own views are absent from the debate. Aim: To explore the pros and cons of glucose monitoring from the patients' perspectives. Design of study: Qualitative repeat-interview study. Setting: Patients were recruited from 16 general practices and three hospital clinics within four local healthcare cooperatives in Lothian, Scotland. Method: Interview data from 40 patients diagnosed with type 2 diabetes within the previous 6 months were analysed using thematic analysis informed by grounded theory. We report findings from round 1 and round 2 interviews. Results: Glucose monitoring can heighten patients' awareness of the impact of lifestyle; for example, dietary choices, on blood glucose levels. Glucose monitoring amplifies a sense of 'success' or 'failure' about self-management, often resulting in anxiety and self-blame if glucose readings remain consistently high. Moreover, monitoring can negatively effect patients' self-management when readings are counter-intuitive. Conclusion: Our analysis highlights the importance of understanding the meanings that newly diagnosed patients attach to glucose self-monitoring. To maximise the positive effects of self-monitoring, health professionals should ensure that patients understand the purpose of monitoring and should clarify with patients how readings should be interpreted. © British Journal of General Practice.

A deficit in encoding the order of visual sequences in developmental dyslexia: a non -phonological deficit

The present thesis tested the hypothesis of Stanovich, Siegel, & Gottardo (1997) that surface dyslexia is the result of a milder phonological deficit than that seen in phonological dyslexia coupled with reduced reading experience. We found that a group of adults with surface dyslexia showed a phonological deficit that was commensurate with that shown by a group of adults with phonological dyslexia (matched for chronological age and verbal and non-verbal IQ) and normal reading experience. We also showed that surface dyslexia cannot be accounted for by a semantic impairment or a deficit in the verbal learning and recall of lexical-semantic information (such as meaningful words), as both dyslexic subgroups performed the same. This study has replicated the results of our published study that surface dyslexia is not the consequence of a mild retardation or reduced learning opportunities but a separate impairment linked to a deficit in written lexical learning, an ability needed to create novel lexical representations from a series of unrelated visual units, which is independent from the phonological deficit (Romani, Di Betta, Tsouknida & Olson, 2008). This thesis also provided evidence that a selective nonword reading deficit in developmental dyslexia persists beyond poor phonology. This was shown by finding a nonword reading deficit even in the presence of normal regularity effects in the dyslexics (when compared to both reading and spelling-age matched controls). A nonword reading deficit was also found in the surface dyslexics. Crucially, this deficit was as strong as in the phonological dyslexics despite better functioning of the sublexical route for the former. These results suggest that a nonword reading deficit cannot be solely explained by a phonological impairment. We, thus, suggested that nonword reading should also involve another ability relating to the processing of novel visual orthographic strings, which we called 'orthographic coding'. We then investigated the ability to process series of independent units within multi-element visual arrays and its relationship with reading and spelling problems. We identified a deficit in encoding the order of visual sequences (involving both linguistic and nonlinguistic information) which was significantly associated with word and nonword processing. More importantly, we revealed significant contributions to orthographic skills in both dyslexic and control individuals, even after age, performance IQ and phonological skills were controlled. These results suggest that spelling and reading do not only tap phonological skills but also order encoding skills.

Finite Groups as the Union of Proper Subgroups

2000 Mathematics Subject Classification: 20D60,20E15.

Rank and k-nullity of contact manifolds

We prove that the dimension of the 1-nullity distribution N(1) on a closed Sasakian manifold M of rankl is at least equal to 2l−1 provided that M has an isolated closed characteristic. The result is then used to provide some examples of k-contact manifolds which are not Sasakian. On a closed, 2n+1-dimensional Sasakian manifold of positive bisectional curvature, we show that either the dimension of N(1) is less than or equal to n+1 or N(1) is the entire tangent bundle TM. In the latter case, the Sasakian manifold Mis isometric to a quotient of the Euclidean sphere under a finite group of isometries. We also point out some interactions between k-nullity, Weinstein conjecture, and minimal unit vector fields.

Generalized cluster states based on finite groups

We define generalized cluster states based on finite group algebras in analogy to the generalization of the toric code to the Kitaev quantum double models. We do this by showing a general correspondence between systems with CSS structure and finite group algebras, and applying this to the cluster states to derive their generalization. We then investigate properties of these states including their projected entangled pair state representations, global symmetries, and relationship to the Kitaev quantum double models. We also discuss possible applications of these states.

Strong shift equivalence, algebraic K-theory, and isolating zero-dimensional dynamics on manifolds

We study the relations of shift equivalence and strong shift equivalence for matrices over a ring $\mathcal{R}$, and establish a connection between these relations and algebraic K-theory. We utilize this connection to obtain results in two areas where the shift and strong shift equivalence relations play an important role: the study of finite group extensions of shifts of finite type, and the Generalized Spectral Conjectures of Boyle and Handelman for nonnegative matrices over subrings of the real numbers. We show the refinement of the shift equivalence class of a matrix $A$ over a ring $\mathcal{R}$ by strong shift equivalence classes over the ring is classified by a quotient $NK_{1}(\mathcal{R}) / E(A,\mathcal{R})$ of the algebraic K-group $NK_{1}(\calR)$. We use the K-theory of non-commutative localizations to show that in certain cases the subgroup $E(A,\mathcal{R})$ must vanish, including the case $A$ is invertible over $\mathcal{R}$. We use the K-theory connection to clarify the structure of algebraic invariants for finite group extensions of shifts of finite type. In particular, we give a strong negative answer to a question of Parry, who asked whether the dynamical zeta function determines up to finitely many topological conjugacy classes the extensions by $G$ of a fixed mixing shift of finite type. We apply the K-theory connection to prove the equivalence of a strong and weak form of the Generalized Spectral Conjecture of Boyle and Handelman for primitive matrices over subrings of $\mathbb{R}$. We construct explicit matrices whose class in the algebraic K-group $NK_{1}(\mathcal{R})$ is non-zero for certain rings $\mathcal{R}$ motivated by applications. We study the possible dynamics of the restriction of a homeomorphism of a compact manifold to an isolated zero-dimensional set. We prove that for $n \ge 3$ every compact zero-dimensional system can arise as an isolated invariant set for a homeomorphism of a compact $n$-manifold. In dimension two, we provide obstructions and examples.

Modelling the development of an online learning resource by health care professionals

The aim of this study was to model the process of development for an Online Learning Resource (OLR) by Health Care Professionals (HCPs) to meet lymphoedema-related educational needs, within an asset-based management context. Previous research has shown that HCPs have unmet educational needs in relation to lymphoedema but details on their specific nature or context were lacking. Against this background, the study was conducted in two distinct but complementary phases. In Phase 1, a national survey was conducted of HCPs predominantly in community, oncology and palliative care services, followed by focus group discussions with a sample of respondents. In Phase 2, lymphoedema specialists (LSs) used an action research approach to design and implement an OLR to meet the needs identified in Phase 1. Study findings were analysed using descriptive statistics (Phase 1), and framework, thematic and dialectic analysis to explore their potential to inform future service development and education theory. Unmet educational need was found to be specific to health care setting and professional group. These resulted in HCPs feeling poorly-equipped to diagnose and manage lymphoedema. Of concern, when identified, lymphoedema was sometimes buried for fear of overwhelming stretched services. An OLR was identified as a means of addressing the unmet educational needs. This was successfully developed and implemented with minimal additional resources. The process model created has the potential to inform contemporary leadership theory in asset-based management contexts. This doctoral research makes a timely contribution to leadership theory since the resource constraints underpinning much of the contribution has salience to current public services. The process model created has the potential to inform contemporary leadership theory in asset-based management contexts. Further study of a leadership style which incorporates cognisance of Cognitive Load Theory and Self-Determination Theory is suggested. In addition, the detailed reporting of process and how this facilitated learning for participants contributes to workplace education theory