3-D Audio in Mobile Communication Devices: Methods for Mobile Head-Tracking

Future generations of mobile communication devices will serve more and more as multimedia platforms capable of reproducing high quality audio. In order to achieve a 3-D sound perception the reproduction quality of audio via headphones can be significantly increased by applying binaural technology. To be independent of individual head-related transfer functions (HRTFs) and to guarantee a good performance for all listeners, an adaptation of the synthesized sound field to the listener's head movements is required. In this article several methods of head-tracking for mobile communication devices are presented and compared. A system for testing the identified methods is set up and experiments are performed to evaluate the prosand cons of each method. The implementation of such a device in a 3-D audio system is described and applications making use of such a system are identified and discussed.

3-D Audio in Mobile Communication Devices: Effects of Self-Created and External Sounds on Presence in Auditory Virtual Environments

This article describes a series of experiments which were carried out to measure the sense of presence in auditory virtual environments. Within the study a comparison of self-created signals to signals created by the surrounding environment is drawn. Furthermore, it is investigated if the room characteristics of the simulated environment have consequences on the perception of presence during vocalization or when listening to speech. Finally the experiments give information about the influence of background signals on the sense of presence. In the experiments subjects rated the degree of perceived presence in an auditory virtual environment on a perceptual scale. It is described which parameters have the most influence on the perception of presence and which ones are of minor influence. The results show that on the one hand an external speaker has more influence on the sense of presence than an adequate presentation of one’s own voice. On the other hand both room reflections and adequately presented background signals significantly increase the perceived presence in the virtual environment.

3-β-d-Glucopyranosyl-6-methoxy-2-benzoxazolinone (MBOA-N-Glc) is an insect detoxification product of maize 1,4-benzoxazin-3-ones

In order to defend themselves against arthropod herbivores, maize plants produce 1,4-benzoxazin-3-ones (BXs), which are stored as weakly active glucosides in the vacuole. Upon tissue disruption, BXs come into contact with β-glucosidases, resulting in the release of active aglycones and their breakdown products. While some aglycones can be reglucosylated by specialist herbivores, little is known about how they detoxify BX breakdown products. Here we report on the structure of an N-glucoside, 3-β-d-glucopyranosyl-6-methoxy-2-benzoxazolinone (MBOA-N-Glc), purified from Spodoptera frugiperda faeces. In vitro assays showed that MBOA-N-Glc is formed enzymatically in the insect gut using the BX breakdown product 6-methoxy-2-benzoxazolinone (MBOA) as precursor. While Spodoptera littoralis and S. frugiperda caterpillars readily glucosylated MBOA, larvae of the European corn borer Ostrinia nubilalis were hardly able to process the molecule. Accordingly, Spodoptera caterpillar growth was unaffected by the presence of MBOA, while O. nubilalis growth was reduced. We conclude that glucosylation of MBOA is an important detoxification mechanism that helps insects tolerate maize BXs.

Kundmachung: Mit Bezug auf die hierortigen Kundmachungen vom 29. v. M. und 3. d. M. betreffend die Wahl des neuen Gemeinderathes für die Stadt Wien ...

Welsch (Projektbearbeiter): Bekanntgabe der Wahlbezirke und -lokale anläßlich der Wahl des neuen Wiener Gemeinderates am 25. und 27. September 1848

Structural studies of proteinase entrapment by human alpha 2-macroglobulin using 3-D electron microscopy

Human a2 -macroglobulin ( a2 M; homotetramer, Mr 720 kDa) is an essential scavenger of proteinases in the serum. Each of its four subunits has a ‘bait region’, with cleavage sequences for almost all endo-proteinases, an unusual thiol ester moiety and a receptor-binding domain (RBD). Bait region cleavage in native a2 M ( a2 M-N) by a proteinase results in rapid thiol ester breakage, with a large-scale structural transformation, in which a2 M uniquely entraps the proteinase in a cage-like structure and exposes receptor-binding domains for rapid endocytosis. Transformed a2 M ( a2 M-TR) contains up to two proteinases, which remain active to small substrates. 3-D electron microscopy is optimally suited to study this unusual structural change at resolutions near (1/30) Å−1. ^ The structural importance of the thiol esters was demonstrated by a genetically-engineered a2 M, with the cysteines involved in thiol ester formation mutated to serines, which appeared structurally homologous to a2 M-TR. This demonstrates that the four highly labile thiol esters alone maintain the a2 M-N structure, while the ‘closed trap’ formed by a2 M-TR is a more stable structural form. ^ Half-transformed a2 M ( a2 M-HT), with cleaved bait regions and thiol esters in only two of its four subunits, provides an important structural link between a2 M-N and a2 M-TR. A comparison with a2 M-N showed the two proteinase-entrapping domains were above and below the plane bisecting the long axis. Both a2 M-N and a2 M-TR consist of two dense, oppositely twisted strands with significant interconnections, indicating that the structural change involves a rotation of these strands. In a2 M-HT these strands were partially untwisted with large central openings, revealing the manner in which the proteinase enters the internal cavity of a2 M. ^ In reconstructions of a2 M-N, a2 M-HT and a2 M-TR labeled with a monoclonal Fab, the Fabs were located on distal ends of each constitutive strand, demonstrating an anti-parallel arrangement of the subunits. Separation between the top and bottom pairs of Fabs was nearly the same on all structures, but the pairs were rotated about the long axis. Taken together, these results indicate that upon proteinase cleavage the two strands in a2 M-N separate. The proteinase enters the structure, while the strands re-twist to encage it. In a2 M-TR, which displays receptor-binding arms, more than two subunits are transformed as strands in the transformed half of a2 M-HT were not separated. ^

A 3-D CT assisted Monte Carlo evaluation of intracavitary brachytherapy implants

Intracavitary brachytherapy (ICB) combined with external beam irradiation for treatment of cervical cancer is highly successful in achieving local control. The M.D. Anderson Cancer Center employs Fletcher Suit Delclos (FSD) applicators. FSD applicators contain shields to limit dose to critical structures. Dosimetric evaluation of ICB implants is limited to assessing dose at reference points. These points serve as surrogates for treatment intensity and critical structure dose. Several studies have mentioned that the ICRU38 reference points inadequately characterize the dose distribution. Also, the ovoid shields are rarely considered in dosimetry. ^ The goal of this dissertation was to ascertain the influence of the ovoid shields on patient dose distributions. Monte Carlo dosimetry (MCD) was applied to patient computed tomography(CT) scans. These data were analyzed to determine the effect of the shields on dose to standard reference points and the bladder and rectum. The hypothesis of this work is that the ICRU38 bladder and rectal points computed conventionally are not clinically acceptable surrogates for the maximum dose points as determined by MCD. ^ MCD was applied to the tandem and ovoids. The FSD ovoids and tandem were modeled in a single input file that allowed dose to be calculated for any patient. Dose difference surface histograms(DDSH) were computed for the bladder and rectum. Reference point doses were compared between shielded and unshielded ovoids, and a commercial treatment planning system. ^ The results of this work showed the tandem tip screw caused a 33% reduction in dose. The ovoid shields reduced the dose by a maximum of 48.9%. DDSHs revealed on average 5% of the bladder surface area was spared 53 cGy and 5% of the rectal surface area was spared 195 cGy. The ovoid shields on average reduced the dose by 18% for the bladder point and 25% for the rectal point. The Student's t-test revealed the ICRU38 bladder and rectal points do not predict the maximum dose for these organs. ^ It is concluded that modeling the tandem and ovoid internal structures is necessary for accurate dose calculations, the bladder shielding segments may not be necessary, and that the ICRU38 bladder point is irrelevant. ^

Visualizing the Simulation of 3-D Underwater Sensor Networks

The majority of sensor network research deals with land-based networks, which are essentially two-dimensional, and thus the majority of simulation and animation tools also only handle such networks. Underwater sensor networks on the other hand, are essentially 3D networks because the depth at which a sensor node is located needs to be considered as well. Due to that additional dimension, specialized tools need to be used when conducting simulations for experimentation. The School of Engineering’s Underwater Sensor Network (UWSN) lab is conducting research on underwater sensor networks and requires simulation tools for 3D networks. The lab has extended NS-2, a widely used network simulator, so that it can simulate three-dimensional networks. However, NAM, a widely used network animator, currently only supports two-dimensional networks and no extensions have been implemented to give it three-dimensional capabilities. In this project, we develop a network visualization tool that functions similarly to NAM but is able to render network environments in full 3-D. It is able to take as input a NS-2 trace file (the same file taken as input by NAM), create the environment, position the sensor nodes, and animate the events of the simulation. Further, the visualization tool is easy to use, especially friendly to NAM users, as it is designed to follow the interfaces and functions similar to NAM. So far, the development has fulfilled the basic functionality. Future work includes fully functional capabilities for visualization and much improved user interfaces.

Modelo de ISING en 3-d. aplicación a sensores magnéticos

El modelo de Ising es un problema de física estadística que tiene solución exacta en dos dimensiones, para el caso de tres dimensiones es preciso utilizar procedimientos de simulación. En este trabajo se ha utilizado un método de Monte Carlo para estudiar el comportamiento del sistema en distintas situaciones, siendo de especial interés el estudio del paso por la transición de fase a la temperatura crítica (Temperatura de Curie, Tc). Se ha estudiado la cinética de los dominios magnéticos, considerando la estructura de los dominios desde el punto de vista de la energía, y en consecuencia, hemos tenido en cuenta la energía de canje que tiende a mantener alineados los espines de los electrones en los materiales ferromagnéticos. Este término contribuye a hacer mayor el espesor de la pared, por la tendencia a que los espines de los átomos vecinos se mantengan alineados. Se ha considerado el ferromagnetismo desde el punto de vista cuántico y basado en las propiedades de simetría de las funciones de onda de los electrones, que se manifiestan en variaciones de la energía electrostática de un sistema en función de la orientación de sus espines. Se han estudiado los efectos de histéresis que resultan al aplicar un campo magnético externo a la red y la orientación de los espines de la misma a lo largo de su evolución. Para la determinación de las propiedades de los materiales ferromagnéticos se utiliza el ciclo de histéresis aunque algunas de las propiedades magnéticas, como la dirección de anisotropía, no pueden ser deducidas directamente de esta manera. Se utilizan distintos métodos para la determinación de la anisotropía de las muestras. El acoplamiento entre la magnetización en zonas próximas a la superficie y la magnetización en zonas internas de la muestra puede ser utilizado para obtener un ciclo de histéresis, que permita obtener sensores magnéticos adaptados a las medidas que se quieran realizar. Mediante el control del campo coercitivo y la susceptibilidad se abre una línea de investigación para el desarrollo de sensores magnéticos

Automatic mesh generation processor for 3-D parabolic boundary discretization

An automatic Mesh Generation Preprocessor for BE Programs with a considerable of capabilities has been developed. This program allows almost any kind of geometry and tipology to be defined with a small amount of external data, and with an important approximation of the boundary geometry. Also the error checking possibility is very important for a fast comprobation of the results.

A Case Study of Geometric Modelling via 3-D Point Interpolation for the Bathymetry of the Rabasa Lakes (Alicante, Spain)

The interpolation of points by means of Information Technology programs appears as a technical tool of some relevancy in the hydrogeology in general and in the study of the humid zones in particular. Our approach has been the determination of the 3-D geometry of the humid zones of major depth of the Rabasa Lakes. To estimate the topography of the lake bed, we proceed to acquire information in the field by means of sonar and GPS equipment. A total of 335 points were measured both on the perimeter and in the lake bed. In a second stage, this information was used in a kriging program to obtain the bathymetry of the wetland. This methodology is demonstrated as one of the most reliable and cost-efficient for the 3-D analysis of this type of water masses. The bathymetric study of the zone allows us to characterize the mid- and long-term hydrological evolution of the lakes by means of depth-area-volume curves.

B.I.E.M.in 3-D elasto-plastic problems

In this paper we present the application of BIEM to elastoplastic axysimetric problems. After a brief presentation of the basic integral formulation we introduce the discretizing and iterative process for its resolution. Simple problems are compared in order to test the possibilities of the method and we finish commenting on future research needs.