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Recently, standardization bodies such as IEEE and ITU addressed, independently, standards for the medium access control (MAC) and physical layer specification of PLCs. MAC designers develop coexistence mechanisms irrespectively of the physical layer. Power line channel behavior changes every time a modem sends/receives on the channel. Changing the channel behavior influences the communication between nodes. As a consequence, the MAC coexistence mechanisms are affected. Power line impedance is a very important parameter on the design of PLC architecture. The changed channel behavior is a result of changing the impedance values between sending and receiving states. Transmitter and receiver nodes behave simultaneously on the power line. Transmitter nodes transmit although other nodes receive at the same time. Changing states from the MAC layer simultaneously between send and receive for the different nodes influence the channel behavior, as a consequence, influence the physical layer and the coexistence between the different nodes even when the systems are separated in frequency. In this paper, we discuss the coexistence of the NB-PLC applications considering the communication requirements. We then investigate the impedance problem of the power line by providing a typical transmission scenario and simulation results on the CENELEC frequency bands. Finally, we introduce a transmission model which overcomes the impedance problem and optimizes the communications between the non-interoperable nodes.
Pedestrian movement analysis at airports - videobased analysis across multiple camera systems
(2013)
In this paper, we describe a method to model human clothes for a later recognition by the use of RGB- and SWIR-cameras. A basic model is estimated during people detection and tracking. This model will be refined if the recognition is triggered. For the refining, several saliency maps are used to extract individual features. These individual features are located separately for any human body parts. The body parts are estimated by the use of a silhouette extraction combined with a skeleton estimation. In this way, the model describes the human clothes in a compact manner which allows the use of a simple and fast comparison method for people recognition. Such models can be used in security and service applications.
It is common to have a large noise and/or a strong interference around the frequency band of a Power Line Communication (PLC) system due to the fact that the PLC channel is not designed for communication. If there are no efficient operations at the receiver to suppress this out-of-band noise and interference to some extent, the Signal-to-Noise Ratio (SNR) will decrease and system will suffer performance loss consequently. Normally, the effort of Analog Front End (AFE) on the suppression of out-of-band interference is finite and it is uneconomic to change the AFE structure to make a performance improvement. Therefore, an appropriate structure of Digital Front End (DFE) at the receiver is necessary to reduce the impact of out-of-band noise and interference furthermore. In this paper, three different kinds of DFE structure at the receiver are introduced: classic DFE, time domain Nyquist windowing and Equivalent Complex Baseband (ECB) approach. The performance of these DFE structures is compared, not only from the aspect of out-of-band suppression, but also from the system overhead they need.
The use of Web Services in modern software development is widely accepted and provides (integrated in an according architecture) a fast, flexible and scalable way for the implementation of modern software products. On the other hand, the development of mobile applications, so called apps, becomes more and more important. While using Web Services also from mobile devices is an already accepted scheme in the development of mobile apps, there is not much work done yet for providing Web Services on mobile devices. Therefore, this paper presents a new perspective to Web Services that could be run on mobile devices and, by this, become mobile Web Services.
One of the technical building blocks of Cloud Computing infrastructures are Web Services. With respect to mobile devices their role as Web Service consumers is widely accepted and today a large number of mobile applications already consume Web Services in order to fulfill their task. Still, not much research is conducted, as yet, to allow deploying Web Services on mobile devices and thus uses these kinds of devices as Web Service providers. This paper presents an analysis of one already implemented approach for provisioning mobile Web Services with respect to energy/battery consumption. Here, after shortly presenting the implementation for the provisioning of mobile Web Services an evaluation of the battery consumption that results in using the approach is presented. Last but not least, an improvement with respect to the battery consumption is presented. The performance test shows that the improved approach provides a reasonable way to introduce Web Service provisioning for mobile devices.
The term “Cloud Computing” does not primarily specify new types of core technologies but rather addresses features to do with integration, inter-operability and accessibility. Although not new, virtualization and automation are cor features that characterize Cloud Computing. In this paper, we intend to explore the possibility of integrating cloud services with educational scenarios without re-defining neither the technology nor the usage scenarios from scratch. Our suggestion is based on certain solutions that have already been implemented and tested for specific cases.