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1

Performance Evaluation of 60-GHz-WPAN System Distributed Over Multi-Mode Fiber

El Yahyaoui M., El Moussati A., Haddadi K.

International Journal of Electronics and Telecommunications

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2017

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Vol. 63, No. 4

381--387

EN

The manuscript deals with the assessment of Radio over Fiber (RoF) system including pure electrical baseband, pure radio frequency band centered around 60 GHz, and hybrid radiooptical system at the same RF band using a global simulation. In this work we focus on RoF solution to improve the low coverage of the 60 GHz channel caused by high free-space attenuation. A realistic co-simulation of the Wireless Personal Area Network (WPAN) IEEE802.15.3c-RoF was performed in a residential environment for Line-Of-Sight (LOS) and Non-Line-Of-Sight (NLOS). In this work, we demonstrated a 60 GHz radio on Multi-Mode Fiber (MMF) using Optical Carrier Suppression (OCS) modulation. The BER (Bit Error Ratio) performance of this system is measured by varying the following parameters: optical launched power, fiber length, modulation format, Channel coding and Signal to Noise Ratio. We show that the RoF at 60 GHz can reach a minimum of 300 m of MMF without optical amplifiers followed by a 5 m wireless transmission with BER less than 10⁻³ in the LOS and NLOS environments.

2

Comparison of Algorithms for Clustering Incomplete Data

Matyja A, Siminski K

Foundations of Computing and Decision Sciences

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2014

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Vol. 39, No. 2

107--127

EN

The missing values are not uncommon in real data sets. The algorithms and methods used for the data analysis of complete data sets cannot always be applied to missing value data. In order to use the existing methods for complete data, the missing value data sets are preprocessed. The other solution to this problem is creation of new algorithms dedicated to missing value data sets. The objective of our research is to compare the preprocessing techniques and specialised algorithms and to find their most advantageous usage.

3

Comparison of incomplete data handling techniques for neuro-fuzzy systems

Sikora M., Simiński K.

Computer Science

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2014

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Vol. 15 (4)

441--458

EN

Real-life data sets sometimes miss some values. The incomplete data needs specialized algorithms or preprocessing that allows the use of the algorithms for complete data. The paper presents a comparison of various techniques for handling incomplete data in the neuro-fuzzy system ANNBFIS. The crucial procedure in the creation of a fuzzy model for the neuro-fuzzy system is the partition of the input domain. The most popular approach (also used in the ANNBFIS) is clustering. The analyzed approaches for clustering incomplete data are: preprocessing (marginalization and imputation) and specialized clustering algorithms (PDS, IFCM, OCS, NPS). The objective of our research is the comparison of the preprocessing techniques and specialized clustering algorithms to find the the most-advantageous technique for handling incomplete data with a neuro-fuzzy system. This approach is also the indirect validation of clustering.

4

Method of non-functional requirements balancing during service development

Globa L., Kot T., Reverchuk A., Schill A.

Journal of Theoretical and Applied Computer Science

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2012

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Vol. 6, nr 3

50-57

EN

Today, the list of telecom services, their functionality and requirements for Service Execution Environment (SEE) are changing extremely fast. Especially when it concerns requirements for charging as they have a high influence on business. This results in the need for constant adaptation and reconfiguration of Online Charging System (OCS) used in mobile operator networks. Moreover any new functionality requested from a service can have an impact on system behavior (performance, response time, delays) which are in general nonfunctional requirements. Currently, this influence and reconfiguration strategies are poorly formalized and validated. Current state-of-the-art approaches are considered methodologies that can model non-functional or functional requirements but these approaches don’t take into account interaction between functional and nonfunctional requirements and collaboration between services. All these result in time and money consuming service development and testing, and cause delays during service deployment. The balancing method proposed in this paper fills this gap. It employs a well-defined workflow with predefined stages for development and deployment process for OCS. The applicability of this novel approach is described in a separate section which contains an example of GPRS service charging. A tool, based on this method will be developed, providing automation of service functionality influence on non-functional requirements and allowing to provide a target deployment model for a particular customer. The reduction of development time and thus necessary financial input has been proved based on real-world experiments.