A highly efficient photovoltaic (PV) system requires a maximum power point tracker to extract peak from PV modules. The conventional variable step-size incremental conductance (INC) tracking (MPPT) technique has two main drawbacks. First, it uses pre-set scaling factor, which manual tuning under different irradiance levels. Second, adapts the slope of characteristics curve vary step-size, means...

We describe a new variant of the well known Baby-Step Giant-Step algorithm in the case of some discrete logarithms with a special structure. More precisely, we focus on discrete logarithms equal to products in groups of unknown order. As an example of application, we show that this new algorithm enables to cryptanalyse a variant of the GPS scheme proposed by Girault and Lefranc at CHES 2004 con...

Giant clams (Tridacnidae) are known to live in association with photosynthetic single cell dinoflagellate algae commonly called zooxanthellae. These algae which can be found in the mantle of the clams are capable of transferring part of their photosynthates which become an important source of energy to the host ( apart from filter feeding activity). In order to understand the basic biological p...

Aims. We report on a search for faint (R total magnitude fainter than 21) and low surface brightness galaxies (R central surface brightness fainter than ∼24) (fLSBs) in a 0.72×0.82 deg2 area centered on the Coma cluster. Methods. We analyzed deep B and R band CCD imaging obtained using the CFH12K camera at CFHT and found 735 fLSBs. The total B magnitudes, at the Coma cluster redshift, range fro...

The Giant Sequoia played several crucial roles in the founding of the modern science of tree -ring dating. These included at least two central theoretical constructs and at least two minor ones; however, historical studies of dendrochronology are actively continuing and this list is expected to expand. Second only to the importance of the ponderosa pine (Pinus ponderosa) in the earliest days of...

We review current progress in the study of the stellar populations of early-type galaxies, both locally and at intermediate redshifts. In particular, we focus on the ages of these galaxies and their evolution in hopes of determining the star formation epochs of their stars. Due to serious remaining systematic uncertainties, we are unable to constrain these epochs precisely. We discuss our resul...

The US government accumulated a large amount of debt from WWII. The government debt-to-GDP ratio in the US peaked at 108% in 1946. This ratio dropped dramatically in the following two decades, to 35% in 1966. Simultaneously, the US experienced a massive baby boom. This paper studies the relationship between these two phenomena in a modified version of the Barro-Becker model. In the model, the g...