In this article we introduce the notion of strongly ${\rm KC}$-spaces, that is, those spaces in which countably compact subsets are closed. We find they have good properties. We prove that a space $(X, \tau )$ is maximal countably compact if and only if it is minimal strongly ${\rm KC}$, and apply this result to study some properties of minimal strongly ${\rm KC}$-spaces, some of which are not possessed by minimal ${\rm KC}$-spaces. We also give a positive answer to a question proposed by O. T. Alas and R. G. Wilson, who asked whether every countably compact ${\rm KC}$-space of cardinality less than $c$ has the ${\rm FDS }$-property. Using this we obtain a characterization of Katětov strongly ${\rm KC}$-spaces and finally, we generalize one result of Alas and Wilson on Katětov-${\rm KC}$ spaces.
Biomechanical simulation activities are seen to undergo considerable growth in volume and scope. More complex and more complete models are now being generated. Biomechanical simulations are considered and extended well into the fields of transport vehicle occupant safety, biomedicine and virtual surgery, ergonomics and into the fields of leisure and sports article manufacture.
For an impact application like a car to pedestrian impact, correct modeling of a knee joint is important for description of the global response and dynamics after the impact. It is also useful for description of possible injuries. Based on the large research of available sources done in [3] in order to create an adequate knee joint, a simple articulated rigid body knee model is introduced. The model is based on the nonlinear joint accommodating flexion-extension and lateral rotation and translation. Joint characteristics are based on public experimental data. Dynamical validation of the new model is provided. The model is implemented into existing human articulated rigid body model ROBBY2 [2] and the frontal impact of a van versus a pedestrian is simulated including comparison to experiment.
The pre-crash activity of the human body is also essential from the point of influencing the global body motion. Hence, the influence of active muscles on the impact kinematics is investigated and comparison to passive model is provided. and Obsahuje seznam literatury
For an $\ell $-cyclically ordered set $M$ with the $\ell $-cyclic order $C$ let $P(M)$ be the set of all monotone permutations on $M$. We define a ternary relation $\overline{C}$ on the set $P(M)$. Further, we define in a natural way a group operation (denoted by $\cdot $) on $P(M)$. We prove that if the $\ell $-cyclic order $C$ is complete and $\overline{C}\ne \emptyset $, then $(P(M), \cdot ,\overline{C})$ is a half cyclically ordered group.
We present an existence theorem for monotonic solutions of a quadratic integral equation of Abel type in C[0, 1]. The famous Chandrasekhar’s integral equation is considered as a special case. The concept of measure of noncompactness and a fixed point theorem due to Darbo are the main tools in carrying out our proof.
The set of points of upper semicontinuity of multi-valued mappings with a closed graph is studied. A topology on the space of multi-valued mappings with a closed graph is introduced.
If $Q$ is a quasigroup that is free in the class of all quasigroups which are isotopic to an Abelian group, then its multiplication group $\mathop {\mathrm Mlt}Q$ is a Frobenius group. Conversely, if $\mathop {\mathrm Mlt}Q$ is a Frobenius group, $Q$ a quasigroup, then $Q$ has to be isotopic to an Abelian group. If $Q$ is, in addition, finite, then it must be a central quasigroup (a $T$-quasigroup).
We reduce the problem on multiplicities of simple subquotients in an $\alpha $-stratified generalized Verma module to the analogous problem for classical Verma modules.
A vertex k-coloring of a graph G is a multiset k-coloring if M(u) ≠ M(v) for every edge uv ∈ E(G), where M(u) and M(v) denote the multisets of colors of the neighbors of u and v, respectively. The minimum k for which G has a multiset k-coloring is the multiset chromatic number χm(G) of G. For an integer l ≥ 0, the l-corona of a graph G, corl (G), is the graph obtained from G by adding, for each vertex v in G, l new neighbors which are end-vertices. In this paper, the multiset chromatic numbers are determined for l-coronas of all complete graphs, the regular complete multipartite graphs and the Cartesian product Kr K2 of Kr and K2. In addition, we show that the minimum l such that χm(corl (G)) = 2 never exceeds χ(G) − 2, where G is a regular graph and χ(G) is the chromatic number of G.