Misha Filip

Integration of Fade Mitigation within centrally managed MF-TDMA/DVB-RCS networks

This paper addresses the integration of a Fade Mitigation Technique FMT within a centrally managed MF-TDMA satellite network in the context of guaranteed QoS delivery. Burst Length Control BLC is introduced as a suitable FMT and the methodology of its design and implementation within the existing DVB-RCS standard is described and simulated. The proposed technique provides compensation for rain attenuation at the expense of capacity utilisation. Within any fixed partition of the MF-TDMA space, by considering the space-time properties of rain attenuation, suitable geographical multiplexing of rain-attenuated and non-attenuated links allows the optimisation of the channel capacity utilisation while still exploiting the statistical multiplexing of the sources on the return channels.

Loop-Back Detection Technique for Uplink Power Control

We present a novel detection technique for uplink power control on satellite links that avoids the use of models of the frequency scaling of rain attenuation. The proposed method is then shown to outperform classical ULPC techniques. The technique is particularly applicable to the real-time detection/compensation of rain attenuation for feeder satellite links. Nomenclature A = 1 ^ ) ( u cnr the clear-sky up-link carrier-to-noise ratio for the link Hub1-to-Satellite u A , d A = uplink, downlink rain attenuation in dB u a , d a = uplink, downlink rain attenuation in ratio B = 1 ^ ) ( d cnr the clear-sky down-link carrier-to-noise ratio for Satellite-to-Hub1 B′ = 2 ^ ) ( d cnr the clear-sky down-link carrier-to-noise ratio for Satellite-to-Hub2 t CNR) ( = the total carrier-to-noise ratio in dB 1 ) ( t cnr = the total carrier-to-noise ratio in ratio for link1 (Hub1-to-Satellite-to-Hub1) 2 ) ( t cnr = the total carrier-to-noise ratio in ratio for link2 (Hub1-to-Satellite-Hub2) 1

Towards a cost-effective design of a meat supply chain: A multi-criteria optimization model

This paper presents a developed multi-criteria optimization model aiming to obtain a cost-effective design for a meat supply chain network with respect to minimization of total implementation and operational cost, and maximization of customer satisfaction and product quality. Moreover, the aim of this work intends to solve the facility location-allocation problem along with the quantities of products transported between facilities. Two solution approaches were employed to obtain two sets of Pareto solutions and a decision-making algorithm was developed to select the superior solution approach in terms of each of values of the three criteria, respectively. A case study was applied to examine the applicability of the developed model and the performance of the proposed solution approaches. Results are offered and discussed in order to determine a trade-off solution among the considered criteria for solving the meat supply chain network design problem. The developed tri-criteria optimization model can be used as an aided tool by decision makers for designing and optimizing food supply chain networks.

Drafting a fuzzy TOPSIS-multi-objective approach for a sustainable supplier selection

In spite of the increasing awareness apparent in the literature regarding the selection of sustainable suppliers, there are limitations in incorporating the sustainable performance in terms of traditional, environmental and social aspects in supplier selection and order allocation. Thus, an integrated fuzzy TOPSIS-multi objective optimization (MOO) approach was developed to integrate sustainable performance into the evaluation and ranking of two-stage supplier selection in conjunction with the optimal order allocation in a meat supply chain. The sustainable performance of suppliers based on traditional, environmental and social criteria was evaluated by using fuzzy TOPSIS. The optimal quantity of products to be ordered from each supplier was determined through a development of multi-objective optimization model. To obtain a set of Pareto solutions derived from the multi-objective optimization model, the LP-metrics method was employed. The quality of the obtained Pareto solutions was evaluated using the global criterion approach aiming to select the final Pareto solution. To examine the applicability of the developed integrated fuzzy TOPSIS-multi-objective approach, a case study was applied.

The Implementation of wideband Cyclostationary Feature Detector with receiver constraints

Cognitive radio system is a context-aware technology in communications. Spectrum sensing is an important function in the implementation of cognitive radio systems by detecting the presence or absence of primary users within the frequency spectrum and makes available free channels for secondary users. Cyclostationary Feature Detector is capable of detecting signals at low signal to noise ratios relying on the signals features such as cyclic frequency, symbol rate, carrier frequency and modulation type. Local oscillator frequency offsets, Doppler effects and jitter produce cyclic and sampling clock offsets at the receiver which will degrade the performance. We propose a multi-slot cyclostationary feature detector that reduces the effects of the offsets by deriving the pair of slot and fast Fourier transform sizes that can be used for implementation. Consequently, this pair was used to show that these offsets can be reduced and also compared the detection performance scenarios with and without offsets.

COST 280: propagation impairment mitigation for millimetre wave radio systems. Results on channel modelling

This paper gives an overview of the Action, its scope and organisation. It also highlights some of the results achieved thus far in the field of channel modelling. The COST Action 280 takes its roots from a previous action, COST 255, and started on the June 2001 with the participation of universities, research institutes, agencies and industries from sixteen European countries. The action focus has been set to the following issues: 1. Channel modelling for satellite and terrestrial systems with particular regard to fade dynamics (fade slopes, fade durations, frequency scaling and scintillations), spatial properties and channel models for application to transfer function or time-series generation. 2. Propagation impairment mitigation techniques (PIMTs) for fixed terrestrial and satellite systems, PIMT resource management algorithms and simulation of systems with PIMT