On alternative approach for verifiable secret sharing

Secret sharing allows split/distributed control over the secret (e.g. master key). Verifiable secret sharing (VSS) is the secret sharing extended by verification capacity. Usually verification comes at the price. We propose "free lunch", the approach that allows to overcome this inconvenience.Comment: This is poster that was presented on ESORICS2002 conference in Zurich. It consists of 4 color pages, with proposal and flowchart

Controlled Deflection Approach for Rotor Crack Detection

Atransverse shaft crack is a serious malfunction that can occurdue to cyclic loading, creep, stress corrosion, and other mechanismsto which rotating machines are subjected. Though studied for manyyears, the problems of early crack detection and warning arestill in the limelight of many researchers. This is dueto the fact that the crack has subtle influence onthe dynamic response of the machine and still there areno widely accepted, reliable methods of its early detection. Thispaper presents a new approach to these problems. The methodutilizes the coupling mechanism between the bending and torsional vibrationsof the cracked, nonrotating shaft. By applying an external lateralforce of constant amplitude, a small shaft deflection is induced.Simultaneously, a harmonic torque is applied to the shaft inducingits torsional vibrations. By changing the angular position of thelateral force application, the position of the deflection also changesopening or closing of the crack. This changes the waythe bending and torsional vibrations are being coupled. By studyingthe coupled lateral vibration response for each angular position ofthe lateral force one can assess the possible presence ofthe crack. The approach is demonstrated with a numerical modelof a rotor. The model is based on the rigidfinite element method (RFE), which has previously been successfully appliedfor the dynamic analysis of many complicated, mechanical structures. TheRFE method is extended and adopted for the modeling ofthe cracked shafts. An original concept of crack modeling utilizingthe RFE method is presented. The crack is modeled asa set of spring-damping elements (SDEs) of variable stiffness connectingtwo sections of the shaft. By calculating the axial deformationsof the SDEs, the opening/closing mechanism of the crack isintroduced. The results of numerical analysis demonstrate the potential ofthe suggested approach for effective shaft crack detection

Auxiliary State Variables for Rotor Crack Detection

In the present study, a new model-based method for rotor crack detection and crack location is proposed. The finiteelement model of the rotor-bearing system accounts for the breathing mechanism of the crack. The model of the rotor system is augmented with an auxiliary single-degree-of-freedom oscillator. The observer is designed and the estimates of its two auxiliary state variables are proposed as crack indicators. The crack location along the shaft is determined by designing a set of observers, which calculate the values of these indicators for different possible crack locations along the shaft. The proposed method is validated numerically and the results prove its capability to detect and locate the crack. Further study will include experimental and numerical investigations to make the approach more robust

Projektowanie i optymalizacja systemów telekomunikacyjnych dla rozproszonej grupy farm fotowoltaicznych o mocy 1MW w Polsce

TFG (en Polonia conocido como "Bachelor of Engineering Thesis") del alumno Witold Bąk en su universidad de origen, la Lodz University of Technology. El alumno fue previamente alumno Erasmus en la Universidad de Alicante. El TFG ha sido cotutorizado por profesores de ambas universidades y ha sido redactado en inglés.After several months of work at I+D Energias, I learned about the construction process of photovoltaic farms in Poland from the perspective of an EPC (Engineering, Procurement and Construction) company. I had the opportunity to work with excellent people on various issues related to construction of the photovoltaic farm, mainly for communication needs. We have introduced optimization of farm monitoring & CCTV systems, which reduces costs and improves the quality of systems. The purpose of the project was to detect and define existing problems in communication needs in a scattered group of 109 photovoltaic farms in Poland of 1 MW each (43 for Energija dossier and 66 for Lords dossier). We optimised monitoring and CCTV systems, we improved the solution for the gateway to the Internet, comparing Energija and Lords dossier, and we introduced a new solution for inverter’s architecture for Lords dossier based on PLC technology, more convenient and compatible with Huawei inverters. All the new solutions and specific technologies presented in this thesis made the construction process a photovoltaic farm in Poland cheaper and faster.I+D Energías y Engineering Services Polsk