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The task of the Center for Language Research is to provide content-based English language instruction for students of computer science and engineering. As such, we find ourselves at the confluence of many of the streams currently running through the English Language Teaching profession, including English for Science and Technology (EST), English for Academic Purposes (EAP), English for Specific Purposes (ESP), Computer-assisted language learning (CALL), content-based instruction, and multimedia applications in foreign language pedagogy. This paper describes our initial attempts to construct a number of World Wide Web pages where students will be able to study EST, EAP, and computer science topics on their own in a multimedia environment.
Education at the University of Aizu is focussed upon computer science. Besides being the subject matter of many courses, however, the computer also plays a vital role in the educational process itself, both in the distribution of instructional media, and in providing students with valuable practical experience. All students have unlimited access (24-hours-a-day) to individual networked workstations, most of which are multimedia-capable (even video capture is possible in two exercise rooms). Without software and content tailored for computer-aided instruction, the hardware becomes an expensive decoration. In any case, there is a need to better educate the instructors and students in the use of the equipment. In the interest of facilitating effective, collaborative use of network-based computers in teaching, this article explores the impact that a network environment can have on such activities. First, as a general overview, and to examine the motivation for the use of a network environment in teaching, this article reviews a range of different styles of collaboration. Then the article shows what kind of tools are available for use, within the context of what has come to be called Computer-Supported Cooperative Work (CSCW).
Broader use of virtual reality environments and sophisticated animations spawn a need for spatial sound. Until now, spatial sound design has been based very much on experience and trial and error. Most effects are hand-crafted, because good design tools for spatial sound do not exist. This paper discusses spatial sound authoring and its applications, including shared virtual reality environments based on VRML. New utilities introduced by this research are an inspector for sound sources, an interactive resource manager, and a visual soundscape manipulator. The tools are part of a sound spatialization framework and allow a designer/author of multimedia content to monitor and debug sound events. Resource constraints like limited sound spatialization channels can also be simulated.
The Sound Spatialization Framework is a C++ toolkit and development environment for providing advanced sound spatialization for virtual reality and multimedia applications. The Sound Spatialization Framework provides many powerful display and user-interface features not found in other sound spatialization software packages. It provides facilities that go beyond simple sound source spatialization: visualization and editing of the soundscape, multiple sinks, clustering of sound sources, monitoring and controlling resource management, support for various spatialization backends, and classes for MIDI animation and handling.
Many different cell types are able to migrate by formation of a thin actin-based cytoskeletal extension. Recently, it became evident that this extension consists of two distinct substructures, designated lamellipodium and lamellum, which differ significantly in their kinetic and kinematic properties as well as their biochemical composition. We developed a stochastic two-dimensional computer simulation that includes chemical reaction kinetics, G-actin diffusion, and filament transport to investigate the formation of growing actin networks in migrating cells. Model parameters were chosen based on experimental data or theoretical considerations. In this work, we demonstrate the system's ability to form two distinct networks by self-organization. We found a characteristic transition in mean filament length as well as a distinct maximum in depolymerization flux, both within the first 1-2 microm. The separation into two distinct substructures was found to be extremely robust with respect to initial conditions and variation of model parameters. We quantitatively investigated the complex interplay between ADF/cofilin and tropomyosin and propose a plausible mechanism that leads to spatial separation of, respectively, ADF/cofilin- or tropomyosin-dominated compartments. Tropomyosin was found to play an important role in stabilizing the lamellar actin network. Furthermore, the influence of filament severing and annealing on the network properties is explored, and simulation data are compared to existing experimental data.
The construction of a basis of a certain lattice of interest is a basic tool in many fields of algorithmic number theory. All too often we can not compute with the original lattices because of irrational numbers involved but have to work with approximations of them. While helpful bounds were shown about the reduction of lattice bases in cite{buchmann94reducing}, here we introduce the notion of a $(epsilon,delta)$-constructable basis of a lattice and determine the precision of vectors that is necessary to extend a set to a $(epsilon,delta)$-constructable basis.
Increasing global awareness of the benefits of electromobility has brought about the need for new concepts in terms of the acoustic design of future vehicle generations. This includes both the creative design process and the development of suitable methods for the evaluation of target sounds by trial participants. The main difference between e-car sound surveys and those carried out on familiar sound categories is the potential consumer’s lack of experience with electric vehicles. Thus the consumer has no, or very unspecific, expectations in this regard. Several studies have consequently shown that many subjects have to construct their personal frame of reference for evaluation within the listening experiment. However, this is possibly at odds with experience-based expectations relating to the sounds of conventional combustion engines. The result is a conflict of objectives between the traditional and the modern, familiarity and strangeness and not least between driving freedom and ecological awareness. In this context, the authenticity of the sound and the subjective interpretability of the sound information also appear as moderator variables. Moreover, associations with other vehicle categories, for example streetcars, also influence the perceived sound quality. In the course of this contribution, these factors will be expounded and their influence on the evaluation of interior noise discussed.
Design of domestic soundscapes - Evaluation of household appliances in laboratory and reality
(2011)
Despite its impressive complexity the cytoskeleton succeeds to persistently organize itself and thus the cells' interior. In contrast to classical man-made machines, much of the cellular organization originates from inherent self-assembly and self-organization allowing a high degree of autonomy for various functional units. Recent experimental and theoretical studies revealed numerous examples of cytoskeleton components that arrange and organize in a self-regulative way. In the present review we want to shortly summarize some of the principle mechanisms that are able to inherently trigger and regulate the cytoskeleton organization. Although taken individually most of these regulative principles are rather simple with intuitively predictable consequences, combinations of two or more of these mechanisms can quickly give rise to very complex, unexpected behavior and might even be able to explain the formation of different functional units out of a common pool of available building blocks.
Cell migration is associated with the dynamic protrusion of a thin actin-based cytoskeletal extension at the cell front, which has been shown to consist of two different substructures, the leading lamellipodium and the subsequent lamellum. While the formation of the lamellipodium is increasingly well understood, organizational principles underlying the emergence of the lamellum are just beginning to be unraveled. We report here on a 1D mathematical model which describes the reaction-diffusion processes of a polarized actin network in steady state, and reproduces essential characteristics of the lamellipodium-lamellum system. We observe a steep gradient in filament lengths at the protruding edge, a local depolymerization maximum a few microns behind the edge, as well as a differential dominance of the network destabilizer ADF/cofilin and the stabilizer tropomyosin. We identify simple and robust organizational principles giving rise to the derived network characteristics, uncoupled from the specifics of any molecular implementation, and thus plausibly valid across cell types. An analysis of network length dependence on physico-chemical system parameters implies that to limit array treadmilling to cellular dimensions, network growth has to be truncated by mechanisms other than aging-induced depolymerization, e.g., by myosin-associated network dissociation at the transition to the cell body. Our work contributes to the analytical understanding of the cytoskeletal extension's bisection into lamellipodium and lamellum and sheds light on how cells organize their molecular machinery to achieve motility.
The Soundtrack Of Your Life
(2012)
Test environments in sound quality research often significantly differ from human’s everyday world. Hence the claim for ecological validity of such experiments is reasonable, but too vague in its bare formulation. The estimation of ecological validity requires theoretical knowledge about the meaning and the totality of factors influencing everyday listening and their interaction. Therefore the influence of “reality factors” on the sound evaluation of household appliances was investigated within the framework of nine experiments. These tests were performed in four different settings with varied reality degrees. The psychological realism and the perceived face validity of the tests were examined by means of interviews. The results reveal, on the one hand, that stimuli are perceived as more pleasant in everyday-like environments. The analysis of the relative judgments shows, on the other hand, that the influence of the experimental realism is moderated by a number of factors. These are the saliency and meaning of the sounds, differences between the assessed devices, and personality traits. The correlation and regression analysis confirms that the perceived sound character is widely independent from experimental realism. However, there is great empirical evidence, that valid assessments of sound quality require the reconstruction of everyday attention and action processes.
The conductor's philosophy
(2013)
Mobile virtual archery
(2013)
Despite their overwhelming complexity, living cells display a high degree of internal mechanical and functional organization which can largely be attributed to the intracellular biopolymer scaffold, the cytoskeleton. Being a very complex system far from thermodynamic equilibrium, the cytoskeleton's ability to organize is at the same time challenging and fascinating. The extensive amounts of frequently interacting cellular building blocks and their inherent multifunctionality permits highly adaptive behavior and obstructs a purely reductionist approach. Nevertheless (and despite the field's relative novelty), the physics approach has already proved to be extremely successful in revealing very fundamental concepts of cytoskeleton organization and behavior. This review aims at introducing the physics of the cytoskeleton ranging from single biopolymer filaments to multicellular organisms. Throughout this wide range of phenomena, the focus is set on the intertwined nature of the different physical scales (levels of complexity) that give rise to numerous emergent properties by means of self-organization or self-assembly.
To power dynamic processes in cells, the actin and microtubule cytoskeletons organize into complex structures. Although it is known that cytoskeletal coordination is vital for cell function, the mechanisms by which cross-linking proteins coordinate actin and microtubule activities remain poorly understood. In particular, it is unknown how the distinct mechanical properties of different actin architectures modulate the outcome of actin-microtubule interactions. To address this question, we engineered the protein TipAct, which links growing microtubule ends via end-binding proteins to actin filaments. We show that growing microtubules can be captured and guided by stiff actin bundles, leading to global actin-microtubule alignment. Conversely, growing microtubule ends can transport, stretch and bundle individual actin filaments, thereby globally defining actin filament organization. Our results provide a physical basis to understand actin-microtubule cross-talk, and reveal that a simple cross-linker can enable a mechanical feedback between actin and microtubule organization that is relevant to diverse biological contexts.