Practical experience is an important component of the educational process. However, the time and economical resources often required for the setting up and construction of scientific laboratories is outside the scope ...
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ISBN:
(纸本)0387240462
Practical experience is an important component of the educational process. However, the time and economical resources often required for the setting up and construction of scientific laboratories is outside the scope of many institutions. A solution to this problem could be found in the adaptation of the Virtual Reality technology, which could allow the creation of Virtual Laboratories, which will simulate the processes and actions that could take place in real laboratories. In particular, this paper, based on the expertise and motivation gained by the VirRAD-IST project, proposes and describes such an educational virtual laboratory, which aims to meet the requirements of a teal laboratory and furthermore to support communication and collaboration services. We propose a web-based system, which allows users to perform experiments on educational fields, such as Physics or Chemistry in 3D multi-user worlds where users are represented by avatars and they are offered a wide range of communication and collaboration services in. order to simulate efficiently a real learning experimental process.
Unicast mechanisms for the adaptive transmission of multimedia data can be used for the transmission of multimedia data over heterogeneous networks, like the Internet with the use of one unicast stream for each receiv...
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Open Hypermedia have come up with several systems, which can provide services to software developers. This paper argues that usability is a critical attribute that should be taken into consideration during the develop...
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In this paper, we present the design principles for virtual spaces and two different tools as solutions for supporting e-collaboration and multi-user communication in web-based learning communities. The first solution...
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In this paper a quantum computer based on the recombination processes happening in semiconductor devices is presented. A "data element" and a "computational element" are derived based on Schokley-R...
In this paper we survey the most well known and widely used indexing structures for handling spatial information using both main memory and secondary media. We focus on the presentation of spatial object indexing stru...
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In this paper we survey the most well known and widely used indexing structures for handling spatial information using both main memory and secondary media. We focus on the presentation of spatial object indexing structures and then we cite a number of applications that they can be used. We have paid attention to the variety of queries that each of these structures can answer and their price in computational time and memory space occupation.
In this paper we address the problem of estimating the number of stations in a wireless network. Under the assumption that each station can detect collisions, we show that it is possible to estimate the number station...
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This paper presents our work in the framework of the 6NET project, regarding the design, implementation and testing of a QoS service in a large-scale IPv6 network. The DiffServ mechanism for providing QoS guarantees, ...
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ISBN:
(纸本)9781622763504
This paper presents our work in the framework of the 6NET project, regarding the design, implementation and testing of a QoS service in a large-scale IPv6 network. The DiffServ mechanism for providing QoS guarantees, is generally preferred over IntServ. However, the current support for QoS mechanisms in IPv6 implementations still lags behind QoS support in IPv4. Furthermore, the new Internet Protocol introduces a different network environment in many aspects and therefore the QoS services should be specifically designed and evaluated for IPv6. In order to evaluate this different behaviour, large-scale experiments have been carried out within the scope of the 6NET project. This paper describes the results from the experimentation with the DiffServ mechanism on a large-scale native IPv6 network that aims to service aggregates of real time traffic with minimum delay, jitter and packet loss.
UNITS, the successor of GSM, is evolving toward a future wireless all-IP network. In this paper we present how it supports real-time IP multimedia services, as these services are expected to drive the adoption of wire...
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ISBN:
(纸本)0780390199
UNITS, the successor of GSM, is evolving toward a future wireless all-IP network. In this paper we present how it supports real-time IP multimedia services, as these services are expected to drive the adoption of wireless all-IP networks. The scheme of real time streaming video is one of the newcomers in wireless data communication and in particular in UNITS, raising a number of novel requirements in both telecommunication and data communication systems. This scheme applies when the mobile user is experiencing real time multimedia content. In this paper, we describe the design and the implementation of a decision feedback scheme, which is based on real time protocols and it is used for streaming video over UNITS transport channels. The decision feedback scheme uses a friendly, to the mobile users, congestion control mechanism to control the transmission rate of the real time video sequence. Furthermore, we evaluate this mechanism through a number of experiments. During these experiments we demonstrate the friendly behavior of the decision feedback scheme to TCP and UDP data streams that coexist in the same channel with the video sequence.
In science learning, cognitive concepts that are distinguished for the complexity of their structure and operation can be understood by using successful metaphors. Conventional instruction is ineffective in dealing wi...
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ISBN:
(纸本)0889864802
In science learning, cognitive concepts that are distinguished for the complexity of their structure and operation can be understood by using successful metaphors. Conventional instruction is ineffective in dealing with misconceptions. We propose a semantic learning interventions management system that utilizes web services technology. The proposed system aims to be an integrated educational solution that offers interoperable, web service-based, cross-platform learning services. It extends the available educational logic and content by publishing and consuming educational web services. Additionally, the combination of Web Services and Semantic Web offers sophisticated capabilities including automated discovery, composition, invocation, and monitoring.
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