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1

Beam Pattern Optimization Via Unequal Ascending Clusters

Abdulqader Ahmed Jameel, Mohammed Jafar Ramadhan, Mohammad Ali Yessar E.

Journal of Telecommunications and Information Technology

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2023

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nr 1

1--7

EN

In this paper, two different architectures based on completely and sectionally clustered arrays are proposed to improve the array patterns. In the wholly clustered arrays, all elements of the ordinary array are divided into multiple unequal ascending clusters. In the sectionally clustered arrays, two types of architectures are proposed by dividing a part of the array into clusters based on the position of specific elements. In the first architecture of sectionally clustered arrays, only those elements that are located on the sides of the array are grouped into unequal ascending clusters, and other elements located in the center are left as individual and unoptimized items (i.e. uniform excitation). In the second architecture, only some of the elements close the center are grouped into unequal ascending clusters, and the side elements were left individually and without optimization. The research proves that the sectionally clustered architecture has many advantages compared to the completely clustered structure, in terms of the complexity of the solution. Simulation results show that PSLL in the side clustered array can be reduced to more than −28 dB for an array of 40 elements. The PSLL was −17 dB in the case of a centrally clustered array, whereas the complexity percentage in the wholly clustered array method was 12.5 %, while the same parameter for the partially clustered array method equaled 10%.

2

Numerical Study of the Effect of Furrows on Biosonar Beamforming in Aselliscus Stoliczkanus Bat

He W., Feng J., Gao L., Zhang Z., Lu H.

Archives of Acoustics

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2017

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Vol. 42, No. 3

395--399

EN

The Aselliscus Stoliczkanus bat, studied here, has intricately shaped structures surrounding the nostrils. These structures are hypothesised to have influence on animals’ acoustic radiation patterns. Using micro-tomography scanning technique, a 3D digital model of the noseleaf is reconstructed and biosonar beam pattern is analysed using a finite element method based on the 3D noseleaf model. The present research focuses on the conspicuous furrows in noseleaf, and our analysis allows to conclude the followings: a) structural details in noseleaf of Aselliscus Stoliczkanus bat can produce acoustic effects even if it is not adjacent to the nostrils, b) the furrows possess frequency-selective characteristics, c) the furrows have the function to manipulate the direction and width of the outgoing ultrasound wave.

3

Badania porównawcze samochodowych żarówek reflektorowych

Targosiński T.

Prace Instytutu Elektrotechniki

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2012

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Z. 256

211-222

PL

Na rynku oferowanych jest wiele odmian samochodowych żarówek reflektorowych. Teoretycznie ich parametry są określone wymaganiami regulaminów homologacyjnych. W ciągu ostatnich lat wzrasta i poszerzana jest oferta żarówek określanych przez producentów jako dające "więcej światła" i oznaczane np. +30% +90% itd. Żarówki te posiadają homologację, jednak konstrukcyjnie nieco różnią się od żarówek typowych. W artykule opisano badania porównawcze tego typu żarówek i żarówek "podstawowych" różnych producentów oraz właściwości wiązki świetlnej reflektorów wytwarzanej przy wykorzystaniu takich żarówek. Badania wykonano za pomocą Analizatora Świateł, a dotyczyły one wybranych parametrów wiązki świetlnej reflektora, które zmieniały się wraz z badaną żarówką.

EN

Market offer many varieties of car headlight bulbs. Theoretically, the parameters are specified by type approval requirements. In recent years, increased and extended the offer of halogen bulbs defined by the manufacturers as offering "more light" e.g. +30%, +90% etc. These bulbs are type approved, but structurally slightly different from conventional light bulbs. This paper describes comparative tests of this type of bulbs of the various manufacturers and headlight beam characteristics produced using such bulbs. The tests was performer using the headlights analyzer AS, and they concerned the beam performance, which have changed with the tested bulb.

4

Objective tests of headlamps in exploitation conditions from traffic safety point of view

Targosiński T.

Journal of KONES

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2007

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Vol. 14, No. 2

493-504

EN

From many years the only exploitation activity regarding headlamps is visual aiming on the base of cut-off line. From one side there are many advanced headlamp designs with excellent performance including gas discharge devices or LED's as light source. In last few years there are many efforts towards to work out laboratory objective quality assessment methods. An example is works of technical committee CIE TC4-45. But in exploitation significant numbers of vehicles are equipped with low quality headlamps installed after repairs. Also many plastic lenses are scratched and tarnished and inside parts of headlamp are dusty. Results of this problems are not noticed during simple periodical technical inspection. In Motor Transport Institute headlight analyzer was worked out. It utilizes CCD camera and computer image analysis and allows test detailed characteristics of beam pattern in garage conditions in objective way. Using these device measurements of many vehicles in exploitation conditions was done. There was find out that significant percentage of headlamps in use does not meet minimum type approval requirements. In paper results of tests are presented and main factors responsible for difference between type approval and exploitation are described.