Dionisis Kandris | University of West Attica / Πανεπιστήμιο Δυτικής Αττικής (original) (raw)

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Papers by Dionisis Kandris

The occurrence of congestion has an extremely deleterious impact on the performance of Wireless S... more The occurrence of congestion has an extremely deleterious impact on the performance of Wireless Sensor Networks (WSNs). This article presents a novel protocol, named COALA (COngestion ALleviation and Avoidance), which aims to act both proactively, in order to avoid the creation of congestion in WSNs, and reactively, so as to mitigate the diffusion of upcoming congestion through alternative path routing. Its operation is based on the utilization of an accumulative cost function, which considers both static and dynamic metrics in order to send data through the paths that are less probable to be congested. COALA is validated through simulation tests, which exhibit its ability to achieve remarkable reduction of loss ratios, transmission delays and energy dissipation. Moreover, the appropriate adjustment of the weighting of the accumulative cost function enables the algorithm to adapt to the performance criteria of individual case scenarios.

ICECS'99. Proceedings of ICECS '99. 6th IEEE International Conference on Electronics, Circuits and Systems (Cat. No.99EX357), 1999

This paper proposes a simple yet effective technique for increasing the capacity and sharing the ... more This paper proposes a simple yet effective technique for increasing the capacity and sharing the control task of any PLC through the use of multi-rate scanning. The I/O binary signals are grouped according to anticipated switching rates to be operated on at different scanning rates. An application example is also presented

Computers and Electronics in Agriculture, 2015

ABSTRACT Many agricultural activities can be highly enhanced by using digital technologies. One o... more ABSTRACT Many agricultural activities can be highly enhanced by using digital technologies. One of these activities is the regulation of the quantity of water in cultivated fields, a process which is directly interwoven with the sustainability and the productivity of crops, since insufficient or excessive irrigation may not only be obstructive, but also destructive. This paper proposes a scheme based on the collaboration of an integrated system for automated irrigation management with an advanced novel routing protocol for Wireless Sensor Networks (WSNs), named ECHERP (Equalized Cluster Head Election Routing Protocol). At its core, the proposed system aims at efficiently managing water supply in cultivated fields in an automated way. The system takes into consideration the historical data and the change on the climate values to calculate the quantity of water that is needed for irrigation. In case that the change on the collected values is above a threshold more frequent data collection is proposed to minimize the necessary quantity of water. On the other hand, in case that the change of the values is below a preset threshold then the time interval to collect data can increase to save sensor energy, leading to a prolonged sensor lifetime. The results show that network lifetime using ECHERP is improved up to 1825 min and if a round is 110 s the model provides energy efficiency using smaller water quantities.

Advances in Mechanical Engineering, 2014

The Scientific World Journal, 2014

2009 17th Mediterranean Conference on Control and Automation, 2009

— Congestion has an utterly detrimental influence in the performance of Wireless Sensor Networks ... more — Congestion has an utterly detrimental influence in the performance of Wireless Sensor Networks (WSNs). Many of the causes of congestion in WSNs are different than the causes of congestion in wired networks. Hence, new research has to be developed for the avoidance and control of congestion in WSNs. This article proposes a scheme which aims to both forecast imminent congestion and prevent its further diffusion in WSNs. The prediction of forthcoming congestion is based on the computation of a suitably built cost function, which considers a set of metrics related with the popularity of the alternate nodes and routing paths. The prevention of congestion diffusion is carried out through multi hop/path routing, by utilizing nodes and routes which are less probable to be congested. Simulation tests performed evaluate the efficacy of the proposed scheme.

— The domain of Wireless Sensor Networks (WSNs) is one of the most rapidly growing scientific fie... more — The domain of Wireless Sensor Networks (WSNs) is one of the most rapidly growing scientific fields. This is because not only the technological advances have enabled the development of advanced sensor nodes with extremely low cost but the potential applications of such structures are ever growing too. WSNs differ from traditional wireless communication networks in several of their characteristics. One of them is power awareness, due to the fact that the batteries of sensor nodes have a restricted lifetime and are difficult to be replaced. Therefore, all protocols must be designed in such a way as to minimize energy consumption and preserve the longevity of the network. That is why, routing protocols in WSNs aim mainly to accomplish power conservation while in traditional networks they focus primarily on the Quality of Service (QoS). Recent advances in WSNs have led to many new protocols specifically designed for sensor networks where energy awareness is an essential issue. This work suggests the development of such hierarchical routing protocol, named SHPER (Scaling Hierarchical Power Efficient Routing), which proves to be particularly effective.

Objectives. In this work, a simple technique to assess the image quality characteristics of the p... more Objectives. In this work, a simple technique to assess the image quality characteristics of the postprocessed image is developed and an easy to use figure of image quality (FIQ) is introduced. This FIQ characterizes images in terms of resolution and noise. In addition information capacity, defined within the context of Shannon's information theory, was used as an overall image quality index. Materials and Methods. A digital mammographic image was postprocessed with three digital filters. Resolution and noise were calculated via the Modulation Transfer Function (MTF), the coefficient of variation, and the figure of image quality. In addition, frequency dependent parameters such as the noise power spectrum (NPS) and noise equivalent quanta (NEQ) were estimated and used to assess information capacity. Results. FIQs for the " raw image " data and the image processed with the " sharpen edges " filter were found 907.3 and 1906.1, correspondingly. The information capacity values were 60.86 × 10 3 and 78.96 × 10 3 bits/mm 2. Conclusion. It was found that, after the application of the postprocessing techniques (even commercial nondedicated software) on the raw digital mammograms, MTF, NPS, and NEQ are improved for medium to high spatial frequencies leading to resolving smaller structures in the final image.

Modern scientific advances have enabled remarkable efficacy for photovoltaic systems with regard ... more Modern scientific advances have enabled remarkable efficacy for photovoltaic systems with regard to the exploitation of solar energy, boosting them into having a rapidly growing position among the systems developed for the production of renewable energy. However, in many cases the design, analysis, and control of photovoltaic systems are tasks which are quite complex and thus difficult to be carried out. In order to cope with this kind of problems, appropriate software tools have been developed either as standalone products or parts of general purpose software platforms used to model and simulate the generation, transmission, and distribution of solar energy. The utilization of this kind of software tools may be extremely helpful to the successful performance evaluation of energy systems with maximum accuracy and minimum cost in time and effort. The work presented in this paper aims on a first level at the performance analysis of various configurations of photovoltaic systems through computer-aided modelling. On a second level, it provides a comparative evaluation of the credibility of two of the most advanced graphical programming environments, namely, Simulink and LabVIEW, with regard to their application in photovoltaic systems.

Abstract: -Blow Molding is a process used in industry in order to manufacture uniform finished pr... more Abstract: -Blow Molding is a process used in industry in order to manufacture uniform finished products that do not need to be joined together in any way. One of the most common industrial quality control problems, which are involved in manufacturing of plastic molded ...

Proceedings - 2011 Panhellenic Conference on Informatics, PCI 2011, 2011

2012 16th Panhellenic Conference on Informatics, 2012