1,720,973 research outputs found
Ultrasonic detection of partial discharge and patterns identification using fast fourier transform and wavelet analysis for insulation failure / Pusparini Dewi Abd. Aziz
No full textThis thesis proposes about the method for locating the source of ultrasonic signals and to detect the different types of partial discharges (PD) i.e. external and internal discharges on cable insulation. PD are the electric discharges in insulating material that does not bridge a pair of electrodes completely. The magnitude of PD is small, but, it can cause deterioration and may lead to breakdown. External PD was created by removing some of the portion of the insulation midway along the length of 5 meters RF Uniradio cable exposing the braid to the air. Internal PD was created by piercing small holes (0.8, 1, 2 and 3 milimetres) on the middle layer of a three parallel sheet of wacker silicone rubber so that it creates void at the inner part of the insulation. The external and internal PD test setup were subjected to a voltage supply of 5kV to 20kV in 2.5 kV level increment, and lkV to 6kV in lkV increment, respectively. The voltage is supplied to the test jigs from low voltage then increased gradually to observe the PD activity in the insulation. The voltage is stopped as the discharges becoming audible and the existence of the spark at the insulation started to occur. The emitted sounds of the external and internal PD are laudable to naked ears at 12.5kV and 5kV respectively. The ultrasonic waves emitted by the PD detector by ultrasonic detector known as the Ultraprobe 2000, where it translate the ultrasonic signal into electrical signal and with the aid of signal converter, the signal can be recorded in the PC. These signals emitted from the discharges are known as faulty signals. The ultrasonic waves of the samples prior to the creation of the holes were also recorded in similar manner. These signals are known as healthy signals. The Fast Fourier Transform (FFT) and Wavelet Analysis (WA) were employed for analysis. With FFT, the signals are represented in frequency-domain and the trend of signal the PD can be detected and be located. There are significant changes in FFT plots for faulty signals when comparing with the FFT plots for healthy signals. The peak magnitude lies on the low frequency range if the signal is healthy, meanwhile, if the signal is faulty, then the peak magnitude lies at the high frequency range. WA analyzes signal in time-domain in order to search for basic or commonly recurring pattern. Here, WA employed the dyadic down sampling technique in the analyses where the procedures taken in order to determine the suitable mother wavelet and its number of level. Each resulting signal produced from the dyadic is compared to the original signal. With different void sizes, it shows that the discharges at larger void size, the lower the peak frequency i.e 4 kV, just before the discharges become audible. It was found that these analyses are able to predict the patterns of faulty signals clearer than the original ultrasonic signals. For the case of external PD, it was found that the suitable mother wavelet is Daubechies at the number of level 7 (db7). For internal PD, the best mother wavelet is Symlet with the number of level 3 (sym3)
Development on micro hydro power generator design using rainwater
No full textthe price of local electrical supply is expected to soar time to time. Furthermore, the
water energy is the clean energy. It has low carbon emissions, therefore the water energy is considered as
green and environment friendly. However, the output will be varies based on the heaviness of the rain since
our country, Malaysia has two seasonsdry and raining season. Micro hydropower generator can generate less
than 100kW of power. The purpose of this project is the development of micro hydropower generator using
rainwater for domestic usage. Basically, rainwater is used as a prime mover of water energy. Firstly, the
rainwater will be stored in a tank before flowing into the turbine. Then, the turbine will rotate and the
electricity will be generated. The recycle water from the turbine will be flowing back into the tank. So, the
water could be reused. The AC voltage and current generated by the generator is converted to DC to suits the
load
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Implementasi Low Power System Untuk Pengambilan Dan Pengiriman Data Berdasarkan Kehadiran Manusia
Full text linkPada zaman modern ini, kemajuan teknologi semakin berkembang pesat
dan kebutuhan akan sumber daya pun semakin meningkat sehingga
meningkatkan pemborosan terhadap sumber daya listrik, dan kehadiran manusia
pada suatu tempat tertentu yang kurang terjangkau menjadi suatu masalah
keaman tersendiri. Dengan munculnya masalah terhadap penggunaan sumber
daya energi listrik dan kemanan suatu tempat tertentu, maka dibutuhkan suatu
alat yang bertujuan untuk menghemat daya yang digunakan yang bertujuan
untuk melakukan pengambilan dan pengiriman data berdasarkan kehadiran
manusa. Dimana merupakan sistem yang dapat digunakan untuk mengamankan
suatu lingkungan tertentu atau pun hanya sebagai pendeteksi kehadiran manusia
dengan penggunaan daya yang rendah, karena sistem tersebut hanya akan
menyala ketika sensor mendeteksi kehadiran manusia. Sistem ini menggunakan
sensor pir sebagai pendeteksi kehadiran manusia dan menggunakan kamera
VC0706 untuk proses pengambilan gambarnya, kemudian gambar disimpan pada
sd card yang terhubung dengan modul Ethernet. Dengan menggunakan
mikrokontroler Arduino Uno sebagai pengolah data yang dihasilkan baik dari
sensor pir maupun kamera. Setelah sistem ini melakukan pengambilan data
gambar maka data yang didapatkan akan dikirimkan kepada orang yang ingin
mengetahui kondisi tempat tertentu dengan cara mengakses alamat IP jaringan
lokal yang telah diatur pada modul Ethernet untuk ditampilkan pada halaman
web browser. Sistem dibuat dengan menggunakan metode low power sleep
mode, dimana ketika sensor tidak mendeteksi apapun maka arus secara otomatis
akan diminalisasi, dengan menggunakan sleep mode besar daya yang dihemat
sebesar 0.010 ampere sampai 0.025 ampere
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