Sensor data integration for indoor human tracking

A human tracking system based on the integration of the measurements from an inertial motion capture system and a UWB (Ultra-Wide Band) location system has been developed. On the one hand, the rotational measurements from the inertial system are used to track precisely all limbs of the body of the human. On the other hand, the translational measurements from both systems are combined by three different fusion algorithms (a Kalman filter, a particle filter and a combination of both) in order to obtain a precise global localization of the human in the environment. Several experiments have been performed to compare their accuracy and computational efficiency.     

Line planning on tree networks with applications to the Quito Trolebús system

We discuss an optimization model for the line planning problem in public transport in order to minimize operation costs while guaranteeing a certain level of quality of service, in terms of available transport capacity. We analyze the computational complexity of this problem for tree network topologies as well as several categories of line operations that are important for the Quito Trolebús system. In practice, these instances can be solved quite well, and significant optimization potentials can be demonstrated.     

Real-time collaboration of virtual laboratories through the Internet

Web-based learning environments are becoming increasingly popular in higher education. One of the most important web-learning resources is the virtual laboratory (VL), which gives students an easy way for training and learning through the Internet. Moreover, on-line collaborative communication represents a practical method to transmit the knowledge and experience from the teacher to students overcoming physical distance and isolation. Considering these facts, the authors of this document have developed a new dynamic collaborative e-learning system which combines the main advantages of virtual laboratories and collaborative learning practices. In this system, the virtual laboratories are based on Java applets which have embedded simulations developed in Easy Java Simulations (EJS), an open-source tool for teachers who do not need complex programming skills. The collaborative e-learning is based on a real-time synchronized communication among these Java applets. Therefore, this original approach provides a new tool which integrates virtual laboratories inside a synchronous collaborative e-learning framework. This paper describes the main features of this system and its successful application in a distance education environment among different universities from Spain.     

Arity and alternation: a proper hierarchy in higher order logics

We study the effect of simultaneously bounding the maximal-arity of the higher-order variables and the alternation of quantifiers in higher-order logics, as to their expressive power on finite structures (or relational databases). Let $\mathit{AA}^i(r,m)$ be the class of (i?+?1)-th order logic formulae where all quantifiers are grouped together at the beginning of the formulae, forming m alternating blocks of consecutive existential and universal quantifiers, and such that the maximal-arity (a generalization of the concept of arity, not just the maximal of the arities of the quantified variables) of the higher-order variables is bounded by r. Note that, the order of the quantifiers in the prefix may be mixed. We show that, for every i?≥?1, the resulting $\mathit{AA}^i(r,m)$ hierarchy of formulae of (i?+?1)-th order logic is proper. This extends a result by Makowsky and Pnueli who proved that the same hierarchy in second-order logic is proper. In both cases the strategy used to prove the results consists in considering formulae which, represented as finite structures, satisfy themselves. As the well known diagonalization argument applies here, this gives rise, for each order i and each level of the $\mathit{AA}^i(r,m)$ hierarchy of arity and alternation, to a class of formulae which is not definable in that level, but which is definable in a higher level of the same hierarchy. We then use a similar argument to prove that the classes of $\Sigma^i_m \cup \Pi^i_m$ formulae in which the higher-order variables of all orders up to i?+?1 have maximal-arity at most r, also induce a proper hierarchy in each higher-order logic of order i?≥?3. It is not known whether the correspondent hierarchy in second-order logic is proper. Using the concept of finite model truth definitions introduced by M. Mostowski, we give a sufficient condition for that to be the case.     

Selective isolation of reversible cold sensitive variants from Chinese hamster ovary cell cultures

The fine structure and cellular associations of the large pigment cells (LPC's) of the compound eye of the house fly were studied with high voltage and conventional electron microscopy. Depending on the sector of the compound eye, the facets are either rectangular or hexagonal. The underside of each facet has indentations exactly aligned with those on top into which inserts an angulated sleeve of LPC's. Under the rectangular lens facet 6 or 8 small compact (in cross section) LPC's join four elongate LPC's. Clusters of compact cells alternate in this ring with elongate ones. Compact cells compress together and become quadrangular (in cross section) several microns below their insertion into the lens and form "building block" corners while elongate cells form "side rails" for the rectangular type of distal pseudocone enclosure. Beneath hexagonal facets all LPC's are rather elongate with out corner cells. In both facet types LPC's enclose the pseudocone for a longitudinal distance of 4 mum and then are displaced as bordering cells by a sleeve of two corneal pigment cells (CPC's), each of which encloses half of the proximal pseudocone. For the following 6 mum of longitudinal distance these concentric sleeves of CPC's and LPC's form a double layer around the pseudocone. At about 10 mum below lens base the two sleeves separate; LPC's become attenuated and extend cable-like to the basement membrane and CPC's enclose the proximal pseudocone, Semper cells and distal retinula. The junction between lens and LPC's has critical structural value in that (1) this is the sole anchorage to the lens by the lengthy remainder of the ommatidium, and (2) LPC's enclose the semiliquid pseudocone in the most distal portion of the pseudocone. In addition to vertical support, the LPC's send out numerous lateral processes that make structural contact among themselves, with the corneal pigment cells and the photoreceptor cells. The structural features of this array are discussed relative to possible physiological roles.     

From a Conceptual Framework for Agents and Objects to a Multi-Agent System Modeling Language

In this paper we propose a multi-agent system modeling language (MAS-ML) that extends UML (Unified Modeling Language) based on structural and dynamic properties presented in a conceptual framework (metamodel) called Taming Agents and Objects (TAO). Our focus is the adaptation according to TAO concepts of the static Class diagram and the interaction Sequence diagram proposed by UML. These two diagrams have been chosen because they are the most commonly used and because it is possible to use them to illustrate both the structural and dynamic aspects of TAO metamodel. We propose a conservative extension of the UML metamodel, which includes agent-related notions that are part of the TAO conceptual framework while preserving all object-related concepts, which constitute the UML metamodel. The main difference between our approach and the others presented in the literature is the clear definition and representation of the elements that compose MASs and their corresponding behavior. In order to extend UML with TAO non-object concepts, it is not possible to use only the three basic extensions mechanisms provided by UML and new metaclasses and stereotypes have been created and associated with the UML metamodel.     

Bacterial polymers as materials for the development of micro/nanoparticles

Bacterial polysaccharides and polyhydroxyalkanoates present physical and chemical characteristics that impart them diverse functional properties, including the ability to produce structures from nano- to macroscale (e.g., spheres, capsules, beads). Such structures may be specially designed to fulfill the requirements of specific applications in different areas, either alone or conjugated with other polymers by means of ionic interactions, hydrogen bonding, or chemical reactions. The interest on using such biomaterials has been increasing due to their unique functional properties, nontoxicity, biodegradability, and biocompatibility. The fields of application of bacterial polymers-based structures include drug delivery, biomedicine, food products, environment, and agriculture, among others.     

True Density and Apparent Density During the Drying Process for Vegetables and Fruits: A Review

Abstract: This review presents the concepts involved in determining the density of foodstuffs, and summarizes the volumetric determination techniques used to calculate true density and apparent density in foodstuffs exposed to the drying process. The behavior of density with respect to moisture content (X) and drying temperature (T) is presented and explained with a basis in changes in structure, conformation, chemical composition, and second‐order phase changes that occur in the processes of mass and heat transport, as reported to date in the literature. A review of the empirical and theoretical equations that represent density is presented, and their application in foodstuffs is discussed. This review also addresses cases with nonideal density behavior, including variations in ρ_s and ρ_w as a function of the inside temperature of the material, depending on drying conditions (X, T). A compilation of studies regarding the density of dehydrated foodstuffs is also presented.