Abstract
In this work, the evaluation of the performance of a small-size photovoltaic plant, with 15 kWp of capacity, is made and some proposals for its optimization are presented. The plant consists of a grid-connected centralized system, where the output power is consumed in the same building. The PV plant production data of the last couple of years are analysed, filtering the periods of inoperation. To obtain an accurate prediction of the efficiency and power output, the characteristics of all plant components were introduced in SAM software. The results obtained through the simulations and the measured output power values were compared. (C) 2018 The Authors. Published by Elsevier Ltd.

Abstract
In a witness hiding protocol the prover tries to convince the verifier that he knows a witness to an instance of an NP problem without revealing the witness. We propose a new look at witness hiding based on the information conveyed in each particular instance of the protocol. We introduce the concept of individual witness hiding (IWH) and prove that zero-knowledge protocols for classical problems like HAM are not IWH. On the other hand, we show that all FewP problems have an IWH protocol. Finally, by introducing a Kolmogorov string commitment protocol we can show that all FewP problems have an IWH protocol that is zero-knowledge relative to an oracle.

Abstract
In the last decade blended learning activities become increasingly popular in the education. According to the current assumption that blended learning equates to the mixture of on-line conferencing and traditional face-to-face learning and contacting. This approach is useful as well as for teaching at institutions as well as for the mobility of students and teachers. Technological possibilities are especially important, while they enable the mobility of students and teachers, in the cases like economic reasons, time constraints, family needs or any other reasons. Without technological supported mobility, those participants would not be able to experience exchange. By mixing technologies and different learning approaches, much has changed in education. Among the new additional challenges of today's education are cross cultural challenges and preparation. Considering this awareness, project experiences and practices in various projects related to blended learning and cultural issues, we will present our suggestions and lessons learned in cross cultural preparation.

Abstract

Abstract
Indoor localization systems typically determine a position using either ranging measurements, inertial sensors, environmental-specific signatures or some combination of all of these methods. Given a floor plan, inertial and signature-based systems can converge on accurate locations by slowly pruning away inconsistent states as a user walks through the space. In contrast, range-based systems are capable of instantly acquiring locations, but they rely on densely deployed beacons and suffer from inaccurate range measurements given non-line-of-sight (NLOS) signals. In order to get the best of both worlds, we present an approach that systematically exploits the geometry information derived from building floor plans to directly improve location acquisition in range-based systems. Our solving approach can disambiguate multiple feasible locations taking into account a mix of LOS and NLOS hypotheses to accurately localize with significantly fewer beacons. We demonstrate our geometry-aware solving approach using a new ultrasonic beacon platform that is able to perform direct time-of-flight ranges on commodity smartphones. The platform uses Bluetooth Low Energy (BLE) for time synchronization and ultrasound for measuring propagation distance. We evaluate our system's accuracy with multiple deployments in a university campus and show that our approach shifts the 80% accuracy point from 4-8m to 1m as compared to solvers that do not use the floor plan information. We are able to detect and remove NLOS signals with 91.5% accuracy.

Abstract
The negotiation is one of the most important phase of the process of buying and selling energy in electricity markets. Buyers and sellers know about their own trading behavior or the quality of their products. However, they can also gather data directly or indirectly from them through the exchange information before or during negotiation, even negotiators should also gather information about past behavior of the other parties, such as their trustworthiness and reputation. Hence, in this scope, reputation models play a more important role in decision-making process in the undertaken bilateral negotiation. Since the decision takes into account, not only the potential economic gain for supported player, but also the reliability of the contracts. Therefore, the reputation component represents the level of confidence that the supported player can have on the opponent’s service, i.e. in this case, the level of assurance that the opponent will fulfil the conditions established in the contract. This paper proposes a reputation computational model, included in DECON, a decision support system for bilateral contract negotiation, in order to enhance the decision-making process regarding the choice of the most suitable negotiation parties. © 2018, Springer International Publishing AG, part of Springer Nature.