1,720,965 research outputs found
PERANCANGAN OPTIMASI DAN IMPLEMENTASI ANTENA HORN SEKTORAL BIDANG-E PADA FREKUENSI BAND-X
No full textDalam makalah ini disajikan tentang antena horn sektoral bidang-E, perancangan optimasi dan implementasinya pada frekuensi gelombang mikro (microwave) band-X,tepatnya 9.000 MH
OPTIMASI PENGARAHAN PANCARAN KE SATELIT KOMUNIKASI BERBASIS ANTENA ARRAY 10 X 10 ELEMEN DENGAN PENGATURAN PENCATU FASA MENGGUNAKAN ALGORITMA GENETIKA
Full text linkPada malakah ini, dikembangkan konsep dasar antena array fasa 10 x 10 elemen dengan mengoptimasi arah pancaran utamanya (elevasi dan azimuth) ke satelit komunkasi yang dituju, dan sekaligus menekan adanya sinyal gangguan yang datang dari arah-arah lain, menggunakan algoritma genetika (AG). Algoritma ini berfungsi untuk mencari nilai koefisien beda fasa pencatu pada setiap elemen antena array, sehingga menghasilkan pola pancaran yang mengoptimasi kualitas sinyal, yakni perbandingan antara level sinyal pada arah satelit komunikasi dan jumlah level-level sinyal pada arah-arah gangguan.Dalam simulasi, elemen antena array diasumsikan sebagai antena isotropis dengan konfigurasi berbentuk planar 10 x 10 elemen, dan jarak antar elemen setengah panjang gelombang. Parameter AG ditentukan: jumlah populasi 100; jumlah generasi 100; probabilitas pindah-silang (cross over) 0,85 dan probabilitas mutasi 0,1.Sebagai ilustrasi, berturut-turut pancaran utama antena diarahkan ke arah satelit (elevasi=0o, azimuth=0o) dengan arah gangguan (40o, 40o); pancaran utama (-30o, -30o) dengan arah gangguan (10o, 10o); pancaran utama (30o, 30o) dengan arah gangguan (-20o, -20o) dihasilkan kualitas sinyal optimal 61,60 dB; 64,55 dB; 64,94 dB.Dari hasil analisa diperoleh kesimpulan, bahwa telah dikembangkan konsep dasar antena array fasa 10 x 10 elemen sebagai pangarahan arah optimum ke satelit komunikasi dan masing-masing menghasilkan kualitas sinyal 61,60 dB; 64,55 dB dan 64,94 dB (di atas 50 dB). Bila diimplementasikan, perlu dipertimbangkan tentang karakteristik propagasi sinyal RF sebenarnya, juga banyaknya elemen antena array yang digunakan dan sistem kontrol pencatuan fasa yang handal
OPTIMASI PENGARAHAN PANCARAN KE SATELIT KOMUNIKASI BERBASIS ANTENA ARRAY 10 X 10 ELEMEN DENGAN PENGATURAN PENCATU FASA MENGGUNAKAN ALGORITMA GENETIKA
Full text linkPada malakah ini, dikembangkan konsep dasar antena array fasa 10 x 10 elemen dengan mengoptimasi arah pancaran utamanya (elevasi dan azimuth) ke satelit komunkasi yang dituju, dan sekaligus menekan adanya sinyal gangguan yang datang dari arah-arah lain, menggunakan algoritma genetika (AG). Algoritma ini berfungsi untuk mencari nilai koefisien beda fasa pencatu pada setiap elemen antena array, sehingga menghasilkan pola pancaran yang mengoptimasi kualitas sinyal, yakni perbandingan antara level sinyal pada arah satelit komunikasi dan jumlah level-level sinyal pada arah-arah gangguan.Dalam simulasi, elemen antena array diasumsikan sebagai antena isotropis dengan konfigurasi berbentuk planar 10 x 10 elemen, dan jarak antar elemen setengah panjang gelombang. Parameter AG ditentukan: jumlah populasi 100; jumlah generasi 100; probabilitas pindah-silang (cross over) 0,85 dan probabilitas mutasi 0,1.Sebagai ilustrasi, berturut-turut pancaran utama antena diarahkan ke arah satelit (elevasi=0o, azimuth=0o) dengan arah gangguan (40o, 40o); pancaran utama (-30o, -30o) dengan arah gangguan (10o, 10o); pancaran utama (30o, 30o) dengan arah gangguan (-20o, -20o) dihasilkan kualitas sinyal optimal 61,60 dB; 64,55 dB; 64,94 dB.Dari hasil analisa diperoleh kesimpulan, bahwa telah dikembangkan konsep dasar antena array fasa 10 x 10 elemen sebagai pangarahan arah optimum ke satelit komunikasi dan masing-masing menghasilkan kualitas sinyal 61,60 dB; 64,55 dB dan 64,94 dB (di atas 50 dB). Bila diimplementasikan, perlu dipertimbangkan tentang karakteristik propagasi sinyal RF sebenarnya, juga banyaknya elemen antena array yang digunakan dan sistem kontrol pencatuan fasa yang handal
STUDI PERBANDINGAN EFISIENSI BAHAN PADA PEMBUATAN ANTENA HORN SEKTORAL BIDANG MEDAN LISTRIK (E)
No full textPada penelitian ini dilakukan studi perbandingan efisiensi bahan pada pembuatan Antena Horn Sektoral Bidang Medan Listrik (Bidang-E). Metodenya, antena-antena tersebut dibuat dari beberapa bahan konduktor, yakni dari bahan seng, almunium, dan tembaga, dengan ukuran yang sama, dan masing-masing diukur direktivitas dan gainnya. Rasio antara direktivtas dan gain merupakan nilai efisiensi dari masing-masing antena. Ketiga antena tersebut dirancang untuk dapat beroperasi pada jaringan wireless LAN 2,4 GHz. Dari hasil pengukuran direktivitas masing-masing antena dari bahan seng, almunium, dan tembaga, berturut-turut diperoleh direktivitas sebesar 13,48 dB, 14,01 dB, dan 14,69 dB. Selanjutnya dengan pengukuran gain dengan metode pembanding, diperoleh gain dari ketiga antena dari bahan seng, almunium dan tembaga sebesar 10,15 dB, 12,15 dB dan 13,15 dB. Sehingga diperoleh efisiensi bahan dari pembutan antena Antena Horn Sektoral Bidang-E dari bahan seng, almunium dan tembaga, masing-masing sebesar 46,45 %, 65,15 %, dan 69,97 %
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Perbandingan Efisiensi Antena Horn Konikal dengan Berbagai Bahan Untuk Aplikasi Wireless LAN 2,4 GHz
No full textConical horn antenna is aperture antenna which is based circular waveguide, while its duct flare to electric field (E) and magnetic field (H) until its final shape resembles conical. In this Final Project, Conical Horn Antenas were designed and made in 2,4 GHz frequency. Three antennas wich had been made in this Final Project have the same size (diameter = 9 cm), but they were made from different materials, which are aluminium, zinc, and copper. Those three different antennas had been compared the efficiencies by measuring the directivity and gain of each antenna. Then, they were implemented on WLAN 2,4 GHz. The driver of the antenna is USB Adapter WiFi. The radiation patterns that resulted in this Final Project had form which were much the same to each other. The HPBWs werre 250 at H-plane and 240 at E-plane. The value of directivity measurement was 18,37 dB for all of the antennas. Gain measurement which had been yielded were 16,15 dB (for copper antenna), 14,15 dB (for aluminium antenna), and 10,15 dB (for zinc antenna). So that the efficiencies were 59,94% for copper antenna, 37,82% for aluminium antenna, and 15,05% for zinc antenna. Based on the value of the QoS parameter measurement, delay increased in the day time. The value of delay, jitter, and throughput measurements were suitable according to the ITU standart, so that those three antennas were competent for video conference. Keyword : Conical Horn Antenna, circular waveguide, wireless LAN (WLAN) 2,4 GHz, USB Adapter WiF
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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