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ABSTRACT: Emerging broadband mobile cellular networks are inherently heterogeneous due to the co-existence of multiple wireless access technologies. In such a network sudden capacity changes are bound to happen due to inter-system handovers, user mobility and flow dynamics. Existing congestion control protocols are shown to deal sufficiently with capacity drops but tend to reach full link utilization slowly after abrupt capacity increases. In this paper we propose SpeedDetect, a simple, sender-side TCP extension for handling sudden capacity increase. The key idea behind our approach is to improve link utilization by explicitly detecting increased link capacity then triggering the underlying congestion control scheme to an aggressive probing regime. We evaluate the performance of SpeedDetect with testbed experiments and simulations. Our findings suggest that the proposed mechanism can significantly improve the reaction time of TCP by detecting sudden capacity increase quickly and consistently. Furthermore, our approach retains the RTT-fairness of the underlying TCP and exhibits favorable inter-protocol fairness towards standard TCP NewReno.
Next Generation Internet Networks, 2009. NGI '09; 08/2009
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ABSTRACT: Forwarding of user data is suspended for a short time at mobile handovers, but arriving packets are still buffered in the network. The resulting sudden peak in utilization may overflow the buffer, and the subsequent bursty packet loss will cause TCP connections to significantly degrade their throughput. We derive an analytical model for buffer overflow probability calculation, given the congestion window increase function and network parameters. Numeric results for current TCP variants and realistic network parameters show that congestion loss occurs with significant probability, even for very large buffer settings.
IEEE Communications Letters 08/2008; · 0.98 Impact Factor
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ABSTRACT: Superflexible robot programming reduces the profitable batch sizes of industrial robots. The paper presents a new way to determine the trajectory for welding robots based on the Intelligent Space concept. The system uses two cameras and edge detection with other image processing algorithms to find the welding path in the image. The three dimensional trajectory is obtained by stereo vision; afterwards it is transformed to the actual robot language.
Human System Interactions, 2008 Conference on; 06/2008
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G. Nemeth
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ABSTRACT: The next generation of intelligent systems provides information processing, retrieval and transfer services for an arbitrary number of users in a transparent way. The structure of large networks is dynamically changing because of failures and modifications. Besides, it must support user mobility as well. The information to be handled extends beyond the traditional fixed type precise and deterministic information, approximating the ones used in natural languages. Such a system cannot be handled by the classical models. The intelligent system can be modelled as having logical, temporal and topological structures together with operations on these structures. The architecture proposed is based on the demand driven information processing model with static or dynamic task allocation over inhomogeneous or homogeneous resource types and network structures. The processing nodes may employ any mix of the four basic information processing models (control, data, demand and information driven models). Introducing a model time as a partially ordered set of events, an evolutionary system can be considered, both in its capabilities and structure. The services of the intelligent system are provided by intelligent mobile agents.
Software, Telecommunications and Computer Networks, 2007. SoftCOM 2007. 15th International Conference on; 10/2007
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ABSTRACT: Smart mobile devices support web technologies, audio and video playback, integrated extra features and 3rd party development beyond telephony. Multimodal user interfaces are favorable in mobile environments, when the traditional standard modality (keyboard and stylus) is supported by other modalities, primarily by speech input and output. Multimodality increases the usability of applications and makes them accessible for impaired persons, although creating multimodal interfaces on mobile devices is a challenging task. This paper investigates the main problems, briefly examines the upcoming issues of the graphical user interface and introduces the most important challenges of creating speech user interfaces on mobile devices. A new approach of creating multimodal, scaleable user interfaces for mobile devices is shortly discussed and some application scenarios are given, as well.
ELMAR, 2007; 10/2007
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ABSTRACT: Portable smart devices are getting more and more popular. Many people prefer smart solutions over old devices or pen-and-paper. But developing applications for mobile devices is a challenging task. First, it is difficult to create an intuitive, easy to use interface; second as current mobile platforms are not compatible, the application must be rewritten on all of them. Furthermore it is not trivial to design multimodal interfaces (including speech and graphical I/O) which really improve software usability. For these reasons our goal is to create an XML based scalable, cross platform, multimodal user interface description format and the corresponding interpreter software for different platforms. This technology makes development for mobile devices much faster and easier.
Mobile and Wireless Communications Summit, 2007. 16th IST; 08/2007
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G. Nemeth
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ABSTRACT: The recent development In telecom has been the drive towards the integration of computing and phone and data communication. With the constant and fast development of technology the phone companies are trying to get a major share in television and advanced video services as well. At the same time cable services are moving towards phone and data services. The new goal is to provide the "triple play": voice, data and television. The main issues are discussed based on personal view of technological and other problems involved.
Telecommunications, 2007. ConTel 2007. 9th International Conference on; 07/2007
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G. Nemeth
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ABSTRACT: An intelligent network provides information processing, retrieval
and transfer services for an arbitrary number of users in a transparent
way. The architecture proposed is based on the demand-driven information
processing model with static or dynamic task allocation over
inhomogeneous or homogeneous resource types and network structures. Such
a system can be modelled as having logical, temporal and topological
structures, together with operations on these structures. The necessary
mathematical concepts for modelling such a system are parameterised
hierarchical relations, logic functions, hierarchies of variables with
their hierarchical control operators, and neighbourhood/similarity
structures. These concepts are then applied to define a knowledge
module. By composition of knowledge modules and intelligent switches, we
obtain the generic intelligent network. Introducing a model time as a
partially ordered set of events, an evolutionary system can be
considered: both its capabilities and its active structure
Knowledge-Based Intelligent Engineering Systems and Allied Technologies, 2000. Proceedings. Fourth International Conference on; 02/2000
