1,721,735 research outputs found
An analysis of the effectiveness of digital tools for marketing nutritional supplements for recreational athletes
No full textRestoring the radiating performances of shortened horn antennas over a broad frequency range
No full text"We propose a flat metamaterial-based lens to be applied to the aperture of a shortened horn antenna in order to achieve gain performances similar to the ones of the corresponding optimum horn over a broad frequency range. In order to achieve an uniform phase distribution at the horn aperture and maximizing, thus, the gain, the central part of the lens consists of a conventional epsilon-positive material and the part closest to the metallic edges of the horn consists of an epsilon-near-zero material, i.e. a wire-medium. Due to the different phase delay of the field at the edges of the aperture on the E- and H-plane, two different wire-mediums are properly designed in order to compensate the phase delay on both planes and achieve the highest possible gain enhancement. As an example, we report the design of the proposed lens for a C-band pyramidal horn. The length of the horn is half the length of the optimum horn, while the obtained gain performances are similar to the ones of the optimal horn over the entire mono-modal frequency band of operation of the feeding waveguide. This result may open the door to several interesting applications in satellite and radar systems.
Unification of segments of guidance lamellas for state roads
No full textUsmerjevalne lamele so del turistične in druge obvestilne signalizacije, ki se postavljajo
predvsem na cestah v naseljih z namenom vodenja pomembnejših objektov in turističnih
ciljev. Postavljajo se v sklopih, in sicer do največ sedem usmerjevalnih lamel v posameznem
sklopu.
Slovenska regulativa vsebuje le splošna določila glede izgleda usmerjevalnih lamel, kar pa je
občutno premalo za vzpostavitev enotnih lamelnih sistemov po vsej državi.
V magistrskem delu so predvsem na osnovi zakonitosti zaznave prometnih znakov
(človeškega faktorja) s strani udeležencev v cestnem prometu obdelani in podani konkretni
predlogi rešitev za naslednje segmente usmerjevalnih lamel: oblika in mere, pisava,
usmerjevalne puščice in simboli. Definirana je tudi siva barva za usmerjevalne lamele
komercialnih vsebin.
Za 50 simbolov, ki so predpisani za uporabo na usmerjevalnih lamelah, je bila s pomočjo
ankete izvedena preveritev njihove prepoznavnosti med vozniki v slovenskem prostoru.
Izsledek kaže na to, da je določene simbole treba spremeniti ali celo ukiniti.
Preverjalo se je tudi največje dopustno število usmerjevalnih lamel v posameznem sklopu, ki
vozniku še omogoča ustrezno zaznavo. Raziskava je bila izvedena s pomočjo teoretičnega
izračuna in opravljenih meritev voznikov na terenu.Guidance lamellas are part of tourist information signs, which are positioned mostly on the
roads in urban areas with the purpose of guiding to important buildings and tourist
destinations. They are set up in sets, up to seven guidance lamellas in the individual set at the
most.
Slovenian regulations comprise of only general provisions regarding guidance lamellas, which
are definitely in sufficient for establishing a unified lamellar system throughout the country.
In the MSc Thesis were above all on the basis of rules of perceiving traffic signs (human
factor) by the participants in road traffic studied and proposed practical solutions for the
following segments of the guidance lamellas: shapes and sizes, fonts, direction arrows and
symbols. Grey colour for guidance lamellas with commercial contents has also been defined.
For 50 symbols, legislated for the use on the guidance lamellas, the verification was
performed by a survey to verify their recognition among the drivers in Slovenia. The finding
indicates that certain symbols should be changed or even abolished.
The maximum permissible number of guidance lamellas in the individual set, which enables
adequate perception to the driver has also been verified. The verification was done by
theoretical method and time measurements of drivers reactions in the field
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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