A block Hankel generalized confluent Vandermonde matrix

Vandermonde matrices are well known. They have a number of interesting properties and play a role in (Lagrange) interpolation problems, partial fraction expansions, and finding solutions to linear ordinary differential equations, to mention just a few applications. Usually, one takes these matrices square, $q\times q$ say, in which case the $i$-th column is given by $u(z_i)$, where we write $u(z)=(1,z,...,z^{q-1})^\top$. If all the $z_i$ ($i=1,...,q$) are different, the Vandermonde matrix is non-singular, otherwise not. The latter case obviously takes place when all $z_i$ are the same, $z$ say, in which case one could speak of a confluent Vandermonde matrix. Non-singularity is obtained if one considers the matrix $V(z)$ whose $i$-th column ($i=1,...,q$) is given by the $(i-1)$-th derivative $u^{(i-1)}(z)^\top$. We will consider generalizations of the confluent Vandermonde matrix $V(z)$ by considering matrices obtained by using as building blocks the matrices $M(z)=u(z)w(z)$, with $u(z)$ as above and $w(z)=(1,z,...,z^{r-1})$, together with its derivatives $M^{(k)}(z)$. Specifically, we will look at matrices whose $ij$-th block is given by $M^{(i+j)}(z)$, where the indices $i,j$ by convention have initial value zero. These in general non-square matrices exhibit a block-Hankel structure. We will answer a number of elementary questions for this matrix. What is the rank? What is the null-space? Can the latter be parametrized in a simple way? Does it depend on $z$? What are left or right inverses? It turns out that answers can be obtained by factorizing the matrix into a product of other matrix polynomials having a simple structure. The answers depend on the size of the matrix $M(z)$ and the number of derivatives $M^{(k)}(z)$ that is involved. The results are obtained by mostly elementary methods, no specific knowledge of the theory of matrix polynomials is needed

A Riemannian Take on Human Motion Analysis and Retargeting

Dynamic motions of humans and robots are widely driven by posture-dependent nonlinear interactions between their degrees of freedom. However, these dynamical effects remain mostly overlooked when studying the mechanisms of human movement generation. Inspired by recent works, we hypothesize that human motions are planned as sequences of geodesic synergies, and thus correspond to coordinated joint movements achieved with piecewise minimum energy. The underlying computational model is built on Riemannian geometry to account for the inertial characteristics of the body. Through the analysis of various human arm motions, we find that our model segments motions into geodesic synergies, and successfully predicts observed arm postures, hand trajectories, as well as their respective velocity profiles. Moreover, we show that our analysis can further be exploited to transfer arm motions to robots by reproducing individual human synergies as geodesic paths in the robot configuration space.Comment: Accepted for publication in IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) 202

On the Design of Region-Avoiding Metrics for Collision-Safe Motion Generation on Riemannian Manifolds

The generation of energy-efficient and dynamic-aware robot motions that satisfy constraints such as joint limits, self-collisions, and collisions with the environment remains a challenge. In this context, Riemannian geometry offers promising solutions by identifying robot motions with geodesics on the so-called configuration space manifold. While this manifold naturally considers the intrinsic robot dynamics, constraints such as joint limits, self-collisions, and collisions with the environment remain overlooked. In this paper, we propose a modification of the Riemannian metric of the configuration space manifold allowing for the generation of robot motions as geodesics that efficiently avoid given regions. We introduce a class of Riemannian metrics based on barrier functions that guarantee strict region avoidance by systematically generating accelerations away from no-go regions in joint and task space. We evaluate the proposed Riemannian metric to generate energy-efficient, dynamic-aware, and collision-free motions of a humanoid robot as geodesics and sequences thereof.Comment: Accepted for publication in IEEE/RSJ Intl. Conf. on Intelligent Robots and Systems (IROS) 2023. 8 pages, 7 figures, accompanying video at https://youtu.be/qT43XgYOlU

Efeito do laser de CO2 na inibição de carie em esmalte adjacente a restaurações de resina composta : estudo in vitro

Orientador : Marines Nobre dos Santos UchoaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: A presente pesquisa objetivou investigar in vitro o efeito do laser de dióxido de carbono (CO2) sobre a inibição da desmineralização do esmalte ao redor de restaurações de resina composta. Para isto, 60 blocos de esmalte dental humano obtidos de terceiros molares retidos foram aleatoriamente divididos em seis grupos, de acordo com tratamentos da interface esmalte-restauração: I (controle) - cavidade preparada com ponta diamantada + condicionamento ácido + adesivo + restauração com resina; II (controle) - igual ao grupo I menos o condicionamento ácido e -o adesivo; III - igual ao grupo I + 1 Watt; IV -igual ao grupo II + 1 Watt; V - igual ao grupo I + 2 Watts e VI - igual ao grupo 11 + 2 Watts. Após este procedimento, os blocos de esmalte foram submetidos às ciclagens térmica e de pH para simular um alto desafio térmico e cariogênico. A desmineralização do esmalte ao redor das restaurações de resina composta de acordo com os diferentes tratamentos foi quantificada pela análise de microdureza. A perda mineral expressa como ^Z (volume% x µm) e a porcentagem de inibição de cárie dos grupos foi analisada estatisticamente pela análise de variância e teste de Tukey, que inicialmente mostrou que o sistema adesivo não teve nenhum efeito em inibir a perda de mineral próximo à interface dente-restauração. As porcentagens de inibição de cárie para os grupos controle, 1 e 2 Watts a 50 e 100µm foram respectivamente: 42,79%; 46.12%; 53,84% e 57,12%. Concluindo, o uso do laser de CO2 (10,6µm) foi efetivo em inibir a cárie dental adjacente a restaurações de resina composta mesmo em situações de alto desafio cariogênicoAbstract: The present research aimed at investigating the ín vítro effect of a carbon dioxide (CO2) laser on the inhibition of enamel demineralization around composite restoration. For this purpose, 60 human enamel blocks obtained from unerupted third molars were randomly divided into six groups, according to the enamel-restoration interface treatments: I (control) - cavity preparation performed with bur + acid conditioning + adhesive + composite restoration; II (control) ¿ same as I minus acid conditioning and adhesive; III - same as group I + 1 Watt; 'V - same as group 11 + 1 Watt; V - same as group, + 2 Watt; and VI - same as group 11 + 2 Watt. After this procedure, the enamel blocks were submitted to a thermal and pH cycling models to simulate a high thermal and cariogenic challenge. The enamel demineralization around composite resin restorations according to the enamel-restoration interface treatments, was quantified by microhardness analysis. The mineral loss as ^Z (volume % x µm) and percentage of caries inhibition for the groups were statistically analyzed by ANOVA and Tukey test that initially showed that the adhesive system had no effect in inhibiting mineral loss at the enamel-restoration interface. The percentages of caries inhibition for groups control, 1 Watt and 2 Watt at 50µm and 100µm were respectively: 42.79%; 46.12%; 53.84% and 57.12%. In conclusion, the use of a CO2 laser (10.6µm) was effective in inhibiting caries in the enamel adjacent to composite resin restorations even in situations of high cariogenic challengeMestradoCariologiaMestre em Odontologi

The Certification of the Mass Concentrations of Aluminium, Selenium and Zinc in Human Serum, BCR-637, BCR-638, BCR-639.

Abstract not availableJRC.D-Institute for Reference Materials and Measurements (Geel

Costs of Persons with Dementia Living in Nursing Homes in The Netherlands

BACKGROUND: Disease modifying treatments (DMTs) currently under development for Alzheimer's disease, have the potential to prevent or postpone institutionalization and more expensive care and might delay institutionalization of persons with dementia. OBJECTIVE: The current study estimates costs of living in a nursing home for persons with dementia in the Netherlands to help inform economic evaluations of future DMTs. METHODS: Data were collected during semi-structured interviews with healthcare professionals and from the financial administration of a healthcare organization with several nursing homes. Personnel costs were calculated using a bottom-up approach by valuing the time estimates. Non-personnel costs were calculated using information from the financial administration of the healthcare organization. RESULTS: Total costs of a person with dementia per 24 hours, including both care staff and other healthcare providers, were € 151 for small-scale living wards and € 147 for independent living wards. Non-personnel costs were € 37 per day. CONCLUSION: This study provides Dutch estimates for total healthcare costs per day for institutionalized persons with dementia. These cost estimates can be used in cost-effectiveness analyses for future DMTs in dementia.</p

The Certification of the Mass Concentrations of Lead and Cadmium in Reconstituted Human Blood. BCR-634, BCR-635, BCR-636.

Abstract not availableJRC.D-Institute for Reference Materials and Measurements (Geel

The Certification of a European Reference Plasma for Factor VIII, BCR-629.

Abstract not availableJRC.D-Institute for Reference Materials and Measurements (Geel