1,720,970 research outputs found
PENGARUH IONOSFER PADA AKURASI PENENTUAN POSISI ABSOLUT DENGAN GPS SINGLE FREQUENCY PADA SAAT TERJADI BADAI MATAHARI
Full text linkThe effect of the ionosphere on the propagation of signals emitted from GPS satellites at an altitude of about 20,000 km is in the form of code delay or carrier advance of the signal propagation time which depends on the Total Electron Content (TEC) and the GPS signals frequency. Coronal Mass Ejections (CMEs) occurred during October 28 and 29, 2003 solar storms have caused ionosphere disturbances called ionospheric storms. The ionospheric storms have degraded the accuration of single frequency GPS absolute positioning to more than 400%. Mitigation of ionospheric storms effect on the single frequency GPS absolute positioning by using Klobuchar model can not produce a significant increase in accuracy. Hence during the ionospheric storms, the regional ionospheric TEC model is needed for ionospheric correction of single frequency GPS absolute point positioning.Pengaruh ionosfer pada propagasi sinyal yang dipancarkan dari satelit GPS pada ketinggian sekitar 20.000 km adalah berupa penundaan waktu propagasi sinyal kode atau percepatan propagasi face GPS yang tergantung pada Total Electron Content (TEC) dan frekuensi sinyal GPS. Coronal Mass Ejections (CMEs) yang terjadi selama badai Matahari pada tanggal 28 dan 29 Oktober 2003 telah menyebabkan gangguan ionosfer, disebut badai ionosfer. Badai ionosfer tersebut telah menyebabkan penurunan akurasi penentuan posisi absolut dengan GPS frekuensi tunggal sampai lebih dari 400%. Mitigasi efek badai ionosfer pada penurunan akurasi posisi tersebut menggunakan model Klobuchar tidak dapat menghasilkan peningkatan akurasi yang signifikan. Oleh karena itu pada saat ada badai ionosfer diperlukan model TEC ionosfer regional untuk koreksi posisi GPS frekuensi tunggal.hal. 70-8
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
HISTERESIS IONOSFER SELAMA SIKLUS MATAHARI KE 23 DARI GLOBAL IONOSPHERIC MAP [IONOSPHERIC HYSTERESIS DURING SOLAR CYCLE 23 FROM GLOBAL IONOSPHERIC MAP]
Full text linkModel-model yang digunakan untuk prediksi ionosfer jangka panjang belum mempertimbangkan efek histeresis ionosfer. Beberapa hasil penelitian pengaruh histeresis ionosfer pada pemodelan ionosfer jangka panjang memberikan kesimpulan yang kontradiktif. Data Total Electron Content (TEC) yang diperoleh dari Global Ionosphere Maps (GIM) telah digunakan untuk penelitian variabilitas spasial dan diurnal histeresis ionosfer selama siklus matahari 23. Besar histeresis diestimasi sebagai perbedaan antara rata-rata TEC selama fase turun dengan rata-rata TEC selama fase naik dari siklus matahari. Histeresis ionosfer memiliki variabilitas spasial yang mirip dengan variabilitas anomali ionisasi ionosfer ekuator, dimana nilai terbesarnya terjadi di daerah puncak anomali ionisasi ionosfer ekuator, dan ada ketidaksimetrissan arah lintang dan bujur. Histeresis ionosfer ekuator dan lintang rendah memiliki pola kejadian yang sistematis baik secara spasial maupun temporal sehingga memungkinkan untuk memasukkan efek histeresis dalam model ionosfer jangka panjang. Histeresis ionosfer di daerah lintang rendah bisa menyebabkan kesalahan dari model linier ionosfer sampai 49 %. Oleh karena itu dalam pemodelan ionosfer lintang rendah hendaknya mempertimbangkan efek histeresis dengan menggunakan formulasi yang berbeda untuk fase naik dan fase turun dari siklus mataharihal. 15-2
PENGUJIAN TEKNIK KORELASI UNTUK DETEKSI PENGARUH AKTIVITAS GEMPA BUMI BESAR PADA IONOSFER [EXAMINATION OF CORRELATION TECHNIQUE FOR DETECTING THE INFLUENCE OF GREAT EARTHQUAKE ACTIVITIES ON IONOSPHERE]
Full text linkTeknik korelasi telah digunakan untuk penelitian deteksi pengaruh aktivitas gempa bumi dari data ionosfer, tetapi penelitian tersebut masih terbatas pada beberapa kasus karena keterbatasan data ionosfer dan kejadian gempa bumi besar. Teknik korelasi belum diuji menggunakan data ionosfer yang lebih luas cakupan spasialnya dan belum menerapkan nilai ambang batas anomali ionosfer. Data ionosfer di atas lokasi terdekat dengan episenter gempa bumi diperoleh dari Global Ionosphere Maps (GIM). Dengan asumsi gempa bumi besar dengan kekuatan ? 8 SR dapat menimbulkan anomali di ionosfer, teknik korelasi dengan penerapan nilai ambang batas anomali ionosfer telah diuji untuk deteksi pengaruh gempa bumi pada ionosfer. Hasil pengujian menunjukkan bahwa mayoritas besar gempa bumi besar tersebut dapat diketahui prekursornya, dan sebagian besar efek gempa bumi tidak dapat dideteksi dari anomali ionosfer. Deteksi prekursor dan efek gempa bumi besar pada ionosfer hanya efektif jika sebelum atau sesudah gempa bumi tidak terjadi badai geomagnet moderat atau lebih kuat. Oleh karena itu penerapan teknik korelasi untuk deteksi pengaruh gempa bumi besar pada ionosfer perlu didukung dengan data aktivitas geomagnet, data geofisika dan atmosfer lainnya jika akan digunakan untuk mendukung sistem peringatan dini gempa bumi besar.hal. 87-10
SELEKSI PARAMETER MASUKAN MODEL TEC IONOSFER DI DAERAH LINTANG RENDAH [INPUT PARAMATERS SELECTION OF IONOSPHERIC TEC MODEL AT LOW LATITUDE REGION]
Full text linkhal. 104-11
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
Ionospheric single station TEC short term prediction at low latitude region in Indonesia using RBF neural network
Full text link18th EISCAT symposium
Session E7: Space weather and modelling
May 27 (Sat), Poster Sessionconference objec
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
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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