The development of research on the maximum power point tracking (MPPT) controller has increased significantly in this decade. The MPPT technique, however, is still demanding because of the ease and simplicity of implementing tracking technique on the maximum power point (MPP). In this paper, MPPT techniques and their modifications from various literature are classified and examined in detail. The discussions are focused on the main objective of obtaining the best possible MPPT technique with the best results at a low cost. The assessment for the selection of MPPT techniques is based on assessments from the previous literature. The discussion of the MPPT technique assessment is divided into two parts. In Part I, the MPPT technique based on constant parameters, and trial-and-error will be discussed in detail, along with its algorithm development in recent times.

The non-linear analysis of hollow-core concrete slabs requires the use of advanced numerical techniques, proper constitutive models both for concrete and steel as well as particular computational skills. If prestressing, cracking, crack opening, material softening, etc. are also to be taken into account, then the computational task can far exceed the capabilities of an ordinary engineer. In order for the calculations to be carried out in a traditional design office, simplified calculation methods are needed. They should be based on the linear finite element (FE) method with a simple approach that takes into account material nonlinearities. In this paper the simplified analysis of hollow-core slabs based on the generalized nonlinear constitutive law is presented. In the proposed method a simple decomposition of the traditional iterative linear finite element analysis and the non-linear algebraic analysis of the plate cross-section is used. Through independent analysis of the plate cross-section in different deformation states, a degraded plate stiffness can be obtained, which allows for iterative update of displacements and rotations in the nodes of the FE model. Which in turn allows to update the deformation state and then correct translations and rotations in the nodes again. The results obtained from the full detailed 3D nonlinear FEM model and from the proposed approach are compared for different slab cross-sections. The obtained results from both models are consistent.

The main object of this article is to present the history of the establishing legal regulations in Poland concerning additional place names and other official signs in the languages of national minorities. This process has been always very difficult, because as it teaches the experience of many European countries, it affects issues related the national identity, the role of the national language in the state and the tradition of recognizing linguistic diversity in a given country. In the article, I will try to show that the introduction of such regulations in Poland has been with the one hand an important, perhaps even historical, change in the functioning of the Polish society and administration which consisted of official admission of other languages into the public sphere thus violating the dominant tradition of Polish language dominance in the country. From the other hand, the presence of a minority place-names indicates a change in the way in which minority groups publicly present their ethnic identities. It takes place not only through maintaining national cultures and learning the mother tongue but also through increased visual presence in the public sphere.