Abstract. In a survey of the inner part of the Galaxy, performed with the H.E.S.S. Instrument (High energy stereoscopic system) in 2004 and 2005, a large number of new unidentified very high energy (VHE) γ-ray sources above an energy of 100 GeV was discovered. Often the γ-ray spectra in these sources reach energies of up to ∼ 10 TeV. These are the highest energy particles ever attributed to sin...

Power grids are facing new challenges as a consequence of an increase in the use of renewable energy sources (RES). The fluctuation in power supply from these energy sources results in insecure and unstable operating points. Furthermore, the integration of distributed energy resources (DER), as well as distributed information systems, poses serious stability and security challenges in power net...

putin’s policies have had significant impact on russian foreign policy after the cold war. despite the fact that putin sought for increasing russia’s power to the same level as the cold war, however; he was aware that the nature of the international system has undergone serious changes. therefore, some specific factors including close collaboration with the united states, an energy-oriented for...