Метод трёхстороннего слияния онтологий на языке OWL 2

Предложен алгоритм трёхстороннего слияния онтологий при многопользовательском редактировании путём попарного сравнения онтологий, основанный на выявлении совпадающих и конфликтующих изменений. Разработана программная реализация алгоритма

Влияние насыщения на индуктивность пазового рассеяния обмотки статора ударного генератора

На основе расчета нелинейного магнитного поля в пазу статора ударного генератора методом конечных разностей получены значения коэффициентов проводимости пазового рассеяния и по коронкам зубцов при различных соотношениях ширины зубца к зубцовому делению

Viscosity and Density of Reference Fluid

The viscosity and density of bis(8-methylnonyl) benzene-1,2- dicarboxylate {diisodecyl phthalate (DIDP)}, with a nominal viscosity at T = 298 K and p = 0.1 MPa of 87 mPa•s, have been measured at temperatures from (298.15 to 423.15) K and pressures from (0.1 to 70) MPa. A vibrating wire viscometer, with a wire diameter of about 0.15 mm, was utilised for the viscosity measurements and the results have an expanded uncertainty, (k = 2), including the error arising from the pressure measurement, of between ±(2 and 2.5) % The density was determined with two vibrating tube densimeters one for operation at p≈0.1 MPa with an expanded uncertainty (k = 2) of about ±0.1 %, the other that used at pressures up to 70 MPa, with an estimated expanded uncertainty (k = 2) of about ±0.3 %. Measurements of density and viscosity were performed on three samples of DIDP each with different purity stated by the supplier and as a function of water mass fraction. The measured viscosity and density are represented by interpolating expressions with differences between the experimental and calculated values that are comparable with the expanded (k = 2) uncertainties. The obtained viscosities at p = 0.1 MPa agree with values reported in the literature within the combined expanded (k = 2) uncertainties of the measurements while our densities differ by no more than 1.5 %. Viscosity data at p > 0.1 MPa deviate systematically from the literature values in the range of -10 % to 10 %. An apparatus capable of simultaneously measuring the solubility of a gas dissolved in a liquid and the viscosity and the density of the resulting mixture over a wide temperature and pressure range was constructed and tested. Preliminary results have been reported

Half a World Away: Contemporary Migration from the European Union to Canterbury, New Zealand

As a traditional country of immigration, New Zealand has often looked outside of its borders for its population composition and as a result 19 percent of New Zealand's current population were born overseas. In recent times, immigration has been used by successive governments as a means of countering severe skills shortages and off-setting a declining birth rate. While attention in the media, public and to some extent in academic circles has been largely focused on the increasing volume of immigrants to New Zealand from Asian countries, migration from Europe has often been overlooked and yet it remains an important component of the New Zealand's migration flows. This thesis explores this stream of migration - from the member states of the European Union to New Zealand - by examining the specific case study of contemporary European Union migration to the Canterbury region, incorporating migrants who live, work and study in Canterbury. The thesis used surveys and in-depth interviews in addition to secondary data to investigate the composition of the European Union migrant population in Canterbury, as well as exploring the motivations and experiences of these migrants. Conceptualising the motivations of contemporary migrants from the EU to New Zealand is difficult, due to a multiplicity of theories and frameworks surrounding the topic of migration. As such, this thesis suggests a three level framework drawn from in order to better understand the motivations of target population. Although the experiences of the surveyed migrants were largely positive, some difficulties were noted, particularly while seeking work and building friendships with New Zealanders. Finally, this thesis proposes a number of recommendations at a policy and academic level which may assist in furthering understandings of the important but often ignored group of European Union migrants in New Zealand

A 3D Data Intensive Tele-immersive Grid

International audienceNetworked virtual environments like Second Life enable distant people to meet for leisure as well as work. But users are represented through avatars controlled by keyboards and mouses, leading to a low sense of presence especially regarding body language. Multi-camera real-time 3D modeling offers a way to ensure a significantly higher sense of presence. But producing quality geometries, well textured, and to enable distant user tele-presence in non trivial virtual environments is still a challenge today. In this paper we present a tele-immersive system based on multi-camera 3D modeling. Users from distant sites are immersed in a rich virtual environment served by a parallel terrain rendering engine. Distant users, present through their 3D model, can perform some local interactions while having a strong visual presence. We experimented our system between three large cities a few hundreds kilometers apart from each other. This work demonstrate the feasibility of a rich 3D multimedia environment ensuring users a strong sense of presence

PetaFlow: a global computing-networking-visualisation unitwith social impact

International audienceThe PetaFlow application aims to contribute to the use of high performance computational resources forthe benefit of society. To this goal the emergence of adequate information and communication technologies withrespect to high performance computing-networking-visualisation and their mutual awareness is required. Thedeveloped technology and algorithms are presented and applied to a real global peta-scale data intensive scientificproblem with social and medical importance, i.e. human upper airflow modelling

Low latency technology for interactive virtual environments

Minimizing system latency is a traditionally important topic for the development of multi-modal Virtual Environments (VE). Human perception thresholds have to be met in order to create immersive environments with a high degree of believability. The system latency has to be in the range of milliseconds, indicating the need for fast interfaces and low system overhead. This thesis provides a comprehensive approach to the creation of multi-modal VEs with high requirements on low latencies, abstract and flexible, yet real-time capable interfaces for device data handling and versatile application support mechanisms. In that sense it offers a stable software and conceptual basis for the development of appealing multi-modal environments. The “Virtueller Kopfhörer” (VirKopf) system is a representative of a demanding multi-modal environment that was developed as a joint research project between the Institute of Technical Acoustics and the VR Group at the Department of Computer Science at RWTH Aachen University. It features binaural acoustics, which enables the placing of virtual sounds at arbitrary 3-D positions within the scene, even very close to the user's head. Headphone-less reproduction is supported by dynamic crosstalk cancellation (CTC). The system is designed for immersive CAVE-like environments. As a cost for this comprehensive system, the requirements for a precise setup and accurate data processing have to be respected very carefully. For example, delivering the correct tracking data with a low latency is most crucial for the successful application of the dynamic CTC. By using CTC, a sweet spot is created, providing a correct sound field impression for the user. In a dynamic system, where the user is free to move arbitrarily, this sweet spot is constantly updated to the current position of the ears of the user, which in term is determined by a tracking device. Due to the discrete processing, a misalignment between the assumed and real position of the user's ears can occur. A misalignment between these positions of above 1 cm is enough to cause audible artefacts for the listener, disrupting the 3-D impression of the auralized scene. This is a severe constraint, as practically the runtime of the sound waves from the loudspeakers to the user's ears can take several milliseconds, and this can not be compensated by faster tracking hardware. Predictive tracking can be used to estimate a future position of the user's ears based on observations from the past. However, these algorithms can not forecast arbitrarily into the future and a low latency system support is a mandatory precondition for a successful application. Low latency processing is not only important for the VirKopf system, but a general requirement on VR software, especially for device and interaction handling. A versatile, flexible and runtime optimal VR device driver architecture is introduced. This architecture enables the parallel low-latency data access for multi-modal data streams and enhanced interaction algorithms as it supports driver-level histories. Additionally, the architecture suggests enhanced transformation and application stages which simplify the application development for the field of VR. The resulting misalignment of the estimation of the user's head in the virtual scene is lowered by an adaptive predictive tracking algorithm. The suggested solution features an on-line update strategy based solely on the local development of the tracking sensor's velocity. The coupling of a visual VR system with its acoustic counterpart as a network communication architecture is defined and its capabilities explained. The cost of end-to-end latency with respect to this audio-visual coupling architecture is inspected and discussed in detail. In addition to the optimized system behavior, an application architecture for multi-modal VEs is described. This approach models VEs as a collection of communicating agents, enabling the building of versatile interactive, multi-modal virtual worlds. A cluster rendering scheme based on a hybrid master-slave architecture is introduced. This approach is furthermore optimized for a minimal latency state processing from master to slave

Low latency technology for interactive virtual environments

Minimizing system latency is a traditionally important topic for the development of multi-modal Virtual Environments (VE). Human perception thresholds have to be met in order to create immersive environments with a high degree of believability. The system latency has to be in the range of milliseconds, indicating the need for fast interfaces and low system overhead. This thesis provides a comprehensive approach to the creation of multi-modal VEs with high requirements on low latencies, abstract and flexible, yet real-time capable interfaces for device data handling and versatile application support mechanisms. In that sense it offers a stable software and conceptual basis for the development of appealing multi-modal environments. The “Virtueller Kopfhörer” (VirKopf) system is a representative of a demanding multi-modal environment that was developed as a joint research project between the Institute of Technical Acoustics and the VR Group at the Department of Computer Science at RWTH Aachen University. It features binaural acoustics, which enables the placing of virtual sounds at arbitrary 3-D positions within the scene, even very close to the user's head. Headphone-less reproduction is supported by dynamic crosstalk cancellation (CTC). The system is designed for immersive CAVE-like environments. As a cost for this comprehensive system, the requirements for a precise setup and accurate data processing have to be respected very carefully. For example, delivering the correct tracking data with a low latency is most crucial for the successful application of the dynamic CTC. By using CTC, a sweet spot is created, providing a correct sound field impression for the user. In a dynamic system, where the user is free to move arbitrarily, this sweet spot is constantly updated to the current position of the ears of the user, which in term is determined by a tracking device. Due to the discrete processing, a misalignment between the assumed and real position of the user's ears can occur. A misalignment between these positions of above 1 cm is enough to cause audible artefacts for the listener, disrupting the 3-D impression of the auralized scene. This is a severe constraint, as practically the runtime of the sound waves from the loudspeakers to the user's ears can take several milliseconds, and this can not be compensated by faster tracking hardware. Predictive tracking can be used to estimate a future position of the user's ears based on observations from the past. However, these algorithms can not forecast arbitrarily into the future and a low latency system support is a mandatory precondition for a successful application. Low latency processing is not only important for the VirKopf system, but a general requirement on VR software, especially for device and interaction handling. A versatile, flexible and runtime optimal VR device driver architecture is introduced. This architecture enables the parallel low-latency data access for multi-modal data streams and enhanced interaction algorithms as it supports driver-level histories. Additionally, the architecture suggests enhanced transformation and application stages which simplify the application development for the field of VR. The resulting misalignment of the estimation of the user's head in the virtual scene is lowered by an adaptive predictive tracking algorithm. The suggested solution features an on-line update strategy based solely on the local development of the tracking sensor's velocity. The coupling of a visual VR system with its acoustic counterpart as a network communication architecture is defined and its capabilities explained. The cost of end-to-end latency with respect to this audio-visual coupling architecture is inspected and discussed in detail. In addition to the optimized system behavior, an application architecture for multi-modal VEs is described. This approach models VEs as a collection of communicating agents, enabling the building of versatile interactive, multi-modal virtual worlds. A cluster rendering scheme based on a hybrid master-slave architecture is introduced. This approach is furthermore optimized for a minimal latency state processing from master to slave