Academic literature on the topic 'Magnitudo di coda'

Pada Jumat, 28 September 2018, pukul 17.02.44 WIB terjadi gempabumi yang berpotensi tsunami di daerah Donggala. BMKG mengeluarkan parameter gempabumi dengan magnitudo 7.7, lokasi 0.18 LS dan 119.85BT atau 26 km dari Utara Donggala. Gempabumi dengan kedalaman 10 km tersebut terjadi dengan mekanisme sesar mendatar akibat aktivitas sesar Palu-Koro dan diikuti oleh ratusan gempabumi susulan. Sesar Palu-Koro melintang dari Selat Makasar sampai pantai utara Teluk Bone memotong jantung kota Palu hingga ke sungai Lariang, Donggala. Studi ini akan merelokasi hiposenter gempabumi Donggala beserta gempabumi pendahulu dan susulannya menggunakan metode hypoRelocate. Relokasi ini menggunakan waktu tempuh mutlak dari 599 gempabumi, beda waktu tempuh relatif dari 2.492 pasangan gempabumi dan waktu dari 11 tumpukan coda cross-correlogram untuk selanjutnya diinversi dengan simulated annealing. Metode ini memiliki kelebihan berupa berupa pengurangan ketergantungan hasil relokasi pada lokasi absolut katalog dengan menyisir waktu tempuh mutlak, pembatasan jarak relatif antargempabumi dengan menggunakan perbedaan waktu tempuh dan koreksi jarak antargempabumi berdasarkan tumpukan coda cross-correlogram. Hasil relokasi menunjukan episenter gempabumi lebih mengumpul atau terfokus daripada posisi awal dan membentuk kluster yang berwujud sebuah bidang dengan luas sekitar 250 km × 85 km. Sebagian besar episenter setelah direlokasi bergeser dengan jarak 15‒20 km dan perubahan kedalaman gempabumi dominan kurang dari 10 km. Arah pergeseran episenter tersebar merata secara acak namun arah barat lebih sedikit dominan. Relokasi menggunakan hypoRelocate menunjukkan peningkatan kualitas yang cukup baik dengan turunnya nilai total residual setelah relokasi. Hasil validasi relokasi hypoRelocate dengan peta citra satelit ALOS-2 mode ScanSAR dan ALOS-2 PALSAR-2 menunjukan bahwa hasil relokasi berada pada bidang sesar akibat gempabumi.

AbstrakPerencanaan struktur bangunan gedung tahan gempa sangat penting di Indonesia, mengingat sebagian besar wilayahnya terletak dalam wilayah gempa dengan intensitas moderat hingga tinggi. SNI gempa telah mengalami banyak perubahan dari waktu ke waktu. Semenjak diterbitkannya peraturan gempa Indonesia SNI 03-1726-2012, Indonesia telah mengalami beberapa kejadian gempa yang amat besar antara lain seperti gempa Mentawai pada tahun 2016 dengan kekuatan 7,8 magnitudo, gempa Lombok 2018 dengan kekuatan 7,0 magnitudo, gempa Palu 2018 dengan kekuatan 7,4 Magnitudo, dan gempa-gempa lainnya, sehingga standar peraturan gempa di Indonesia mengalami pembaharuan menjadi SNI 03-1726-2019. Penelitian ini bertujuan mengetahui pengaruh gaya gempa berdasarkan peraturan SNI 03-1726-2012 dan SNI 03-1726-2019 dengan meninjau besar gaya geser dasar, simpangan dan simpangan antar lantai. Hasil analisis menunjukkan bahwa perbandingan gaya geser dasar yang terjadi adalah sebesar 47% untuk arah Y dan 69% untuk arah X, perbandingan simpangan maksimum yang terjadi sebesar 1.17% untuk arah X dan 0.92% untuk arah Y, serta peningkatan simpangan antar lantai maksimum terjadi sebesar 0.6-1.2%. AbstractThe design of earthquake resistant building structure is very important in Indonesia, considering that most of the area is located in eartquakes areas with moderate to high intensity. Indonesian Code for earthquake has undergone many changes from time to time. Since Indonesian earthquake code SNI 03-1726-2013 has been published, Indonesia has experienced several large earthquakes, such as Mentawai eatchquake with magnitude of 7.8 in 2016, Lombok earthquake with magnitude of 7.0 in 2018, Palu earhquake with magnitude of 7.0 and 7.4 in 2018 and others, so that the earthquake code in Indonesia has been updated to SNI 03-1726-2019. This study aims to determine the effect of earthquake load based on SNI 03-1726-2019 and SNI 03-1726-2012 by observing the base-shear forces, drift and story drift. The result show that the differences of base shear forces are 47% for Y direction and 69% for X-direction, the maximum drift differences are 1.17% for X direction and 0.92% for Y direction, the increase percentage of story drift is 0.6-1.2%.

Beberapa metode ekstraksi fitur untuk sistem identifikasi pembicara memiliki kelemahan yaitu ketika dilingkungan berderau hasil akurasinya menurun. Metode ekstraksi fitur Mel-Frequency Cepstral Coefficient (MFCC) merupakan metode ekstraksi sinyal suara yang peka terhadap derau. Metode MFCC menghasilkan akurasi yang tinggi ketika dilingkungan yang bersih. Sebaliknya ketika di lingkungan yang berderau akurasi yang dihasilkan turun drastis. Penelitian ini mengusulkan metode ekstraksi fitur menggunakan MFCC digabung dengan algoritma deteksi endpoint. Algoritma deteksi endpoint memisahkan daerah speech dan nonspeech. Daerah nonspeech biasanya lebih banyak berisi derau sehingga bisa dijadikan informasi derau. Informasi derau diekstrak dan menghasilkan magnitude frekuensi derau. Uji coba metode yang diusulkan menghasilkan nilai akurasi yang lebih tinggi pada semua tipe derau dan tingkat SNR. Akurasi yang dihasilkan oleh metode yang diusulkan lebih tinggi 14.69% dibanding metode MFCC, 6.4% dibanding metode MFCC+wiener, dan 2.74% dibanding metode MFCC+Spectral Subtraction (SS).

In this paper, a drive-by damage detection methodology for high-speed railway (HSR) bridges is addressed, to appraise the application of Mel-frequency cepstral coefficients (MFCC) to extract the Damage Index (DI). A finite element (FEM) 2D VTBI model that incorporates the train, ballasted track and bridge behavior is presented. The formulation includes track irregularities and a damaged condition induced in a specified structure region. The feasibility of applying cepstrum analysis components to the indirect damage detection in HSR by on-board sensors is evaluated by numerical simulations, in which dynamic analyses are performed through a code implemented in MATLAB. Different damage scenarios are simulated, as well as external excitations such as measurement noises and different levels of track irregularities. The results show that MFCC-based DI are highly sensitive regarding damage detection, and robust to the noise. Bridge stiffness can be recognized satisfactorily at high speeds and under different levels of track irregularities. Moreover, the magnitude of DI extracted from MFCC is related to the relative severity of the damage. The results presented in this study should be seen as a first attempt to link cepstrum-based features in an HSR drive-by damage detection approach.

Abstract Local tri-directional pattern (LtriDP) is a method of extracting local intensity features from each pixel based on direction. However, this method has not been able to provide good performance in extracting features for image retrieval. One reason that makes image retrieval performance worse is the effect of lighting. Lighting can cause large variations between images. This study proposed utilization of Histogram Equalization (HE). Histogram equalization is a functional method of stretching gray degrees and expanding image contrast. This will make variations in the gray level of the original image can be controlled. There are several main stages in this study, firstly query image and image dataset will be preprocessed with histogram equalization. After that, the image is extracted by a tri-directional pattern and magnitude pattern are searched. A tri-directional pattern will produce two histograms, while a magnitude pattern produces one histogram. The three histograms are combined or joint histogram is performed. Histogram that has been joint is a feature vector. The feature vector will be calculated using a similarity measurement Canberra. After that, an image similar to the query image will be obtained. The experiment was conducted using 3 face datasets namely ORL, BERN, and YALE. The average recall value was 0.422 for the ORL dataset, 0.50 for the BERN dataset, and 0.63 for the YALE dataset. The evaluation show, the proposed method can be used as a process of improving the quality of image datasets in the image retrieval system. Keywords: Image retrieval system, Local tri-directional pattern, Streching Image, Histogram Equalization, Similarity Measurement Canberra. Abstrak Local tri-directional pattern (LtriDP) merupakan salah satu metode ekstraksi fitur intensitas lokal dari setiap piksel berdasarkan arah. Namun, metode ini belum mampu memberikan performa yang baik dalam mengekstrak fitur untuk temu kembali citra. Salah satu alasan yang membuat performa temu kembali citra tidak baik adalah pengaruh pencahayaan. Pencahayaan dapat menyebabkan variasi besar antar citra. Penelitian ini mengusulkan pemanfaatan Histogram Equalization (HE). HE merupakan metode fungsional dalam peregangan derajat keabuan dan memperluas kontras citra. Hal ini akan membuat variasi level keabuan dari citra asli dapat terkendali. Ada beberapa tahapan utama dalam penelitian ini, yang pertama citra query dan citra dataset akan terlebih dahulu di preprocessing dengan histogram equalization. Setelah itu, citra tersebut diekstrak fiturnya, dicari pola tri-directional dan pola magnitude. Pola tri-directional akan menghasilkan dua histogram, sedangkan pola magnitude menghasilkan satu histogram. Ketiga histogram tersebut kemudian disatukan atau dilakukan joint histogram. Histogram yang telah dijoint merupakan vektor fitur. Vektor fitur tersebut akan dihitung rankingnya menggunakan pengukuran jarak canberra. Setelah itu, akan didapatkan citra yang mirip dengan citra query. Uji coba dilakukan dengan menggunakan 3 dataset wajah yaitu ORL, BERN, dan YALE. Nilai rata-rata recall yang di dapatkan 0,422 untuk dataset ORL, 0,50 untuk dataset BERN, dan 0,63 untuk dataset YALE. Dari hasil evaluasi tersebut, dapat disimpulkan metode yang diusulkan dapat digunakan sebagai proses peningkatan kualitas dataset citra pada system temu kembali citra. Keywords: Sistem Temu Kembali Citra, Local tri-directional pattern, Peregangan Kontras, Histogram Equalization, Perhitungan Jarak Canberra.

ABSTRACTThis research is based on the magnitude of children's interest in smartphone until they ignore to study. Most children who play smartphone are only for watching videos and playing games which are attractive to them. Therefore, the researcher designed an educative game Android-based application so they can play smartphone by not ignoring the development of reading skill. The purpose of this research is to describe the design of development, appropriateness, and product testing.This research uses the Design Based Research (DBR) method developed by Reeves. Data collection is done by observation, expert judgment, and documentation techniques. The setting and subject of this research are 6 kindergarten children in group B Nyimas Oyoh Kindergarten and 2 children from the researcher’s home. The Educative game android-based application development uses Adobe Flash Player for the main software. After validating, phase I trial, revision, and phase II trial, this educative game is appropriate to be used to facilitate reading skill of children aged 5-6 years.The research produced product that is an educative game learning with Uvi in application installed at smartphone with a minimum version of Jelly Bean, and a guide book on educative game learning with Uvi. Penelitian ini dilatarbelakangi karena besarnya ketertarikan anak pada smartphone sehingga mengabaikan belajar. Kebanyakan anak yg bermain smartphone hanya untuk menonton video-video dan bermain permainan yang menarik bagi anak. Oleh karena itu, peneliti merancang educative game berbasis aplikasi android agar anak dapat bermain smartphone dengan tidak mengabaikan perkembangan keterampilan membacanya. Tujuan dari penelitian ini yaitu mendeskripsikan rancangan pengembangan, kelayakan, dan uji coba produk. Penelitian ini menggunakan metode Design Based Research (DBR) yang dikembangkan oleh Reeves. Pengumpulan data dilakukan dengan teknik observasi, expert judgment, dan dokumentasi. Setting dan subjek penelitian ini adalah 6 orang anak kelompok B TK Nyimas Oyoh dan 2 orang anak dari lingkungan rumah. Pengembangan Educative game berbasis aplikasi android ini menggunakan Adobe Flash Player sebagai software utamanya. Setelah melakukan validasi, uji coba tahap I, revisi, dan uji coba tahap II, educative game ini layak digunakan dalam memfasilitasi keterampilan membaca anak usia 5-6 tahun. Penelitian ini menghasilkan produk berupa educative game belajar Bersama Uvi dalam bentuk aplikasi yang dapat digunakan di perangkat keras berupa smartphone dengan versi minimal Jelly Bean, dan buku panduan penggunaan educative game belajar bersama Uvi.

AbstrakPenelitian ini bertujuan untuk mengetahui besarnya hubungan Kepercayaan Diri Siswa Dengan Hasil Belajar PAK Di Kelas VII SMP Negeri 4 Sumbul Kabupaten Dairi Tahun Pembelajaran 2020/2021, dengan hipotesis terdapat hubungan yang positif dan signifikan antara Kepercayaan Diri Siswa Dengan Hasil Belajar PAK Di Kelas VII SMP Negeri 4 Sumbul Kabupaten Dairi Tahun Pembelajaran 2020/2021. Penelitian ini menggunakan pendekatan kuantitatif deskriptif inferensial, dengan populasi seluruh siswa kelas VII SMP Negeri 4 Sumbul yang berjumlah 86 orang dengan sampel berjumlah 65 orang. Data dikumpulkan dengan angket tertutup sebanyak 31 item yang disusun oleh penulis berdasarkan indikator variabel sesuai teori ahli. Uji coba angket dilakukan kepada 21 siswa yang bukan responden penelitian, dan telah diuji validitas dan reliabilitasnya. Hasil analisis data menunjukkan bahwa terdapat hubungan yang positif dan signifikan antara Kepercayaan Diri Siswa Dengan Hasil Belajar PAK Di Kelas VII SMP Negeri 4 Sumbul Kabupaten Dairi Tahun Pembelajaran 2020/2021 dengan koefisien korelasi rhitung rtabel atau 0,612 0,244 dan uji signifikan hubungan diperoleh thitungttabel sebesar 6,148 2,000, dengan demikiandapat disimpulkan Ho ditolak dan Ha diterima .Katakunci : Hasil belajar, Kepercayaan diri Abstract This study aims to determine the magnitude of the relationship between Student Confidence and PAK Learning Outcomes in Class VII Sumbul, Dairi District, 2020/2021 Learning Year, with the hypothesis that there is a positive and significant relationship between Student Confidence and PAK Learning Outcomes in Class VII SMP Negeri 4 Sumbul Regency. Dairi Academic Year 2020/2021. This study used an inferential descriptive quantitative approach, with a population of all students of class VII SMP Negeri 4 Sumbul, totaling 86 people with a sample of 65 people. Data were collected using a closed questionnaire of 31 items compiled by the author based on variable indicators according to expert theory. Questionnaire trials were conducted on 21 students who were not research respondents, and had tested their validity and reliability. The results of data analysis show that there is a positive and significant relationship between Student Confidence and PAK Learning Outcomes in Class VII SMP Negeri 4 Sumbul Dairi Regency 2020/2021 Learning Year with a correlation coefficient r count r table or 0.612 0.244 and a significant correlation test is obtained t count t table of 6, 148 2,000, thus it can be concluded that Ho is rejected and Ha is accepted.Keywords: Learning Outcomes, Self-Confidence

Abstract. The Italian earthquake waveform data are collected here in a dataset suited for machine learning analysis (ML) applications. The dataset consists of nearly 1.2 million three-component (3C) waveform traces from about 50 000 earthquakes and more than 130 000 noise 3C waveform traces, for a total of about 43 000 h of data and an average of 21 3C traces provided per event. The earthquake list is based on the Italian Seismic Bulletin (http://terremoti.ingv.it/bsi, last access: 15 February 2020​​​​​​​) of the Istituto Nazionale di Geofisica e Vulcanologia between January 2005 and January 2020, and it includes events in the magnitude range between 0.0 and 6.5. The waveform data have been recorded primarily by the Italian National Seismic Network (network code IV) and include both weak- (HH, EH channels) and strong-motion (HN channels) recordings. All the waveform traces have a length of 120 s, are sampled at 100 Hz, and are provided both in counts and ground motion physical units after deconvolution of the instrument transfer functions. The waveform dataset is accompanied by metadata consisting of more than 100 parameters providing comprehensive information on the earthquake source, the recording stations, the trace features, and other derived quantities. This rich set of metadata allows the users to target the data selection for their own purposes. Much of these metadata can be used as labels in ML analysis or for other studies. The dataset, assembled in HDF5 format, is available at http://doi.org/10.13127/instance (Michelini et al., 2021).

Seismic status in Bangladesh has been investigated using earthquake data recorded by the global network of USGS during 1980 to 2016. Seismicity parameters such as magnitude completeness Mc, b-value and a-value are being estimated. It has observed that the overall b-value in and around Bangladesh is of 0.84 which is seemed to be seismically active zone. As, reliable b-value assessment can lead to better seismic hazard analysis, reliable magnitude of completeness Mc can lead to b-value assessment of an area, this work has dealt and estimated magnitude of completeness Mc using various techniques for the whole region for a reliable estimation. Estimated Mc is obtained to be around 3.9-4.7, which lead to b-value of 0.93. Spatial variations of Mc and b-value have been investigated for 1ox1o horizontal and vertical rectangular regions for the study area between 18-29°N and 84-95°E. Estimated Mc and b-value along with b-value are then averaged for the common regions in the pair of horizontal and vertical regions. Results are then being presented in the form of maps. The findings resemble as, the Mc is low at the border line of N-W Bangladesh, and a line from Cox’s bazaar to Sylhet through Hill tracts. Remain parts belong to the Mc value of 4.1-4.2, thus the b-value obtained is varying from 0.68 to 1.2, where, the value is higher at region in Chittagong and Barisal division that extends toward north through part of Dhaka to Sylhet and lower at Rajshahi, Rangpur and part of Khulna division, while a-value is varying from 5.0 to 7.2 mostly from west to east.ReferencesAbercrombie R.E., and Brune J.N., 1994. Evidence for a constant b-value above magnitude 0 in the southern San Andreas, San Jacinto, and San Miguel fault zones and at the Long Valley caldera, California. Geophys. Res. Lett., 21(15), 1647-1650.Aki K., 1965. Maximum likelihood estimate of b in the formula log N=a-b M and its confidence limits. Bull. Earthquake Res Inst., Tokyo Univ., 43, 237-239.Aki S., 1987. On nonparametric tests for symmetry. Ann. Inst. Statist. Math., 39, 457-472.Al-Hussaini T.M., 2006. Seismicity and Seismic Hazard Assessment in Bangladesh: Reference to Code Provisions. Meeting on Seismic Hazard in Asia ICTP, Trieste, Dec. 4-8.Amorese D., 2007. Applying a change-point detection method on frequency-magnitude distributions. Bull. Seismol. Soc. Am., 97(5), 1742-1749. Doi:10.1785/0120060181.Banglapedia, 2012. The National Encyclopedia of Bangladesh. http://en.banglapedia.org/index.php?title=Tectonic_Framework, retrieved on 31 Aug 2017.Cao A.M., and Gao S.S., 2002. Temporal variations of seismic b-values beneath northeastern Japan island arc. Geophys. Res. Lett., 29(9), 481-483. Doi:10.1029/2001GL013775.Das R., Wason H.R., and Sharma M.L., 2012. Temporal and spatial variations in the magnitude of completeness for homogenized moment magnitude catalogue for northeast India. J. Earth Syst. Sci., 121(1), 19-28.Felzer K.R., 2008. Simulated aftershock sequences for a M 7.8 earthquake on the southern San Andreas fault. Seismol. Res. Lett., 80, 21-25.GSB, 2018. Seismic Zone Map of Bangladesh. http://gsb.portal.gov.bd/sites/default/files/files/gsb.portal.gov.bd/common_document/a6e75ad2_5acd_4fe3_911d_c9d25a7e349e/BD_Sciesmic-zonemap(NBC).pdf, retrieved on 31 March 2018.Gutenberg B., and Richter C.F., 1944. Frequency of earthquakes in California, Bull. Seismol. Soc. Am., 34, 184-188.Gutenberg B., and Richter C.F., 1956. Earthquake magnitude, intensity, energy and acceleration (second paper). Bull. Seismol Soc. Am., 46(2), 105-145.Hafiez H.E.A., 2015. Estimating the magnitude of completeness for assessing the quality of earthquake catalogue of the ENSN. Egypt. Arab J. Geosci., 8(1), 9315-9323. 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Doi:10.1007/s11069-011-9898-1.Lomnitz-Adler J., and Lomnitz C., 1979. A modified form of the Gutenberg-Richter magnitude-frequency relation. Bull. Seism. Soc. Am., 69(4), 1209-1214.Marsan D., 2003. Triggering of seismicity at short timescales following Californian earthquakes. J. Geophys. Res., 108, B5, 2266. Doi:10.1029/2002JB001946.Mignan A., 2011. Retrospective on the Accelerating Seismic Release (ASR) hypothesis: Controversy and new horizons. Tectonophysics, 505(1), 1-16. Doi:10.1016/j.tecto.2011.03.010.Mignan A., and Woessner J., 2012. Estimating the magnitude of completeness for earthquake catalogs, Community Online Resource for Statistical Seismicity Analysis. Swiss Seismological Service, ETH Zurich, 145p. Doi:10.5078/corssa-00180805. Available at http://www.corssa.org.Naylor M., Orfanogiannaki, K., and Harte D., 2010. Exploratory data analysis: magnitude, space, and time. Community Online Resource for Statistical Seismicity Analysis, 42p. Doi:10.5078/corssa-92330203. Available at http://www.corssa.org.Ogata Y., and Katsura K., 1993. Analysis of temporal and spatial heterogeneity of magnitude frequency distribution inferred from earthquake catalogues. Geophys. J. Int., 113(3), 727-738. Doi:10.1111/j.1365-246X.1993.tb04663.x.Ogata Y., and Katsura K., 2006. Immediate and updated forecasting of aftershock hazard. Geophys. Res. Lett., 33, 10, L10305. Doi:10.1029/2006GL025888.Rashid H., 1991. Geography of Bangladesh, University Press Ltd, Bangladesh; 2nd edition, 545p.Reimann K.U., 1993. Geology of Bangladesh. Gerbruder Bornt Ramerg, Berlin, Germany, 160p.Siddique S., 2015. Gutenberg-Richter recurrence law to seismicity analysis of Bangladesh. IABSE-JSCE Joint Conference on Advances in Bridge Engineering-III, August 21-22, Dhaka, Bangladesh.Shi Y., and Bolt B.A., 1982. The standard error of the magnitude-frequency b-value. Bull. Seismol. Soc. Am., 72(5), 1667-1687.USGS, 2012. 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Learning in the 21st century requires students to have skills, knowledge and abilities in the fields of technology, media and information. This research is a development research that aims to see the magnitude of the increase in student learning outcomes who are taught using Prezi-based learning media with the ASSURE model. This development research has produced a product in the form of Prezi-based learning media that has been validated by experts and users. Learning resources are designed according to student characteristics and based on user needs analysis. The results of content validation in the field of study for Prezi media are 96 percent, in the very appropriate category, 98 percent in learning design experts in the very appropriate category, linguists 94 percent in the very appropriate category. Educator user test of 80 percent product is very feasible. The average small group learning outcomes for the pre-test was 48.50, while the post-test was 83.50. In the field test, the average learning outcomes for the pre-test were 47.14 while the post-test was 85.71. So it can be concluded that there was an increase in learning outcomes in the small group by 72.2 percent with high qualifications and in the field trial an increase in learning outcomes by 82 percent with very high qualifications. The conclusion from the research and development of Prezi-based learning media is feasible to use and proven to improve student learning outcomes. Recommendations made based on the results of this study are the use of technology-based media so as to improve student learning outcomes. Pembelajaran di abad 21 menuntut siswa untuk memiliki keterampilan, pengetahuan dan kemampuan di bidang teknologi, media dan informasi. Penelitian ini merupakan penelitian pengembangan yang bertujuan untuk melihat besarnya peningkatan hasil belajar siswa yang diajar menggunakan media pembelajaran berbasis Prezi dengan model ASSURE. Penelitian pengembangan ini telah menghasilkan produk berupa media pembelajaran berbasis Prezi yang telah divalidasi oleh ahli dan pengguna. Sumber belajar dirancang sesuai dengan karakteristik siswa dan berdasarkan analisis kebutuhan pengguna. Hasil validasi isi bidang kajian untuk media Prezi adalah 96 persen, pada kategori sangat sesuai, ahli desain pembelajaran 98 persen pada kategori sangat sesuai, ahli bahasa 94 persen pada kategori sangat sesuai. Uji pengguna pendidik produk 80 persen sangat layak. Rata-rata hasil belajar kelompok kecil untuk pre-test adalah 48,50, sedangkan post-test adalah 83,50. Pada uji lapangan rata-rata hasil belajar pre-test 47,14 sedangkan post-test 85,71. Sehingga dapat disimpulkan terjadi peningkatan hasil belajar pada kelompok kecil sebesar 72,2 persen dengan kualifikasi tinggi dan pada uji coba lapangan terjadi peningkatan hasil belajar sebesar 82 persen dengan kualifikasi sangat tinggi. Kesimpulan dari penelitian dan pengembangan media pembelajaran berbasis Prezi layak digunakan dan terbukti dapat meningkatkan hasil belajar siswa. Rekomendasi yang dibuat berdasarkan hasil penelitian ini adalah penggunaan media berbasis teknologi sehingga dapat meningkatkan hasil belajar siswa.

2009/2010
Questa tesi di dottorato va a descrivere un lavoro che comprende due diverse parti: scenari di pericolosità sismica e stima degli effetti di sito e magnitudo di coda. La prima parte tratta di scenari di pericolosità sismica in un’area che copre la regione Friuli Venezia Giulia, la parte occidentale della Slovenia e la parte orientale del Veneto. Poichè parte della tesi è stata svolta nell’ambito del progetto Interreg Italia-Austria, Hareia, "Historical and recent earthquakes in Italy and Austria", è stato trattato anche un evento localizzato nella regione Trentino Alto Adige. La pericolosità sismica, espressa in termini di accelerazione o velocità massima attesa sul territorio, è stata dedotta in base al calcolo di molteplici scenari realistici di scuotimento del suolo con eventi connessi a faglie segnalate in letteratura come le più significative dell’area in esame. Questo approccio permette di ottenere una buona stima sull’eventuale pericolosità dell’area, importante per mitigare gli effetti di potenziali terremoti futuri. Le sorgenti sismogenetiche prese in esame sono state tredici. Tutti i calcoli sono stati eseguiti usando un modello di faglia estesa, applicando un modello di velocita’ di propagazione della rottura costante e variando la posizione dell’epicentro lungo la superficie di faglia. La distribuzione del momento sismico è stata considerata sia omogenea che, applicando il modello k², non uniforme. In questo modo, per ogni modello di faglia, possono essere calcolati diversi scenari. I sismogrammi sintetici sono stati calcolati con una frequenza massima di 1 Hz e per ogni punto di una densa griglia di ricevitori posizionati in modo equidistante dal centro della sorgente. Quindi, da ognuno di questi ricevitori, e’ stato possibile ottenere il valore massimo dell’accelerazione e delle velocità del sismogramma, poi plottato sulla mappa finale. Nella seconda parte della tesi, proprio perchè nella metodologia adottata gli scenari di scuotimento del suolo non tengono conto degli effetti di sito, si è applicata la metodologia di Mayeda et al. (2003), per poter ottenere, a diverse strette bande di frequenza, la risposta delle varie stazioni sismiche prese in esame. Il risultato potrà essere usato in futuro per “correggere” le stime di pericolosità calcolate su roccia. Come input a questa metodologia, è stato scelto un database costituito da 200 eventi avvenuti fra il 2006 ed il 2009, con magnitudo locale da 2.5 a 4, registrati da 25 stazioni slovene, austriache ed italiane. Di questi terremoti è stata infine calcolata anche la magnitudo da momento di coda. I valori di magnitudo così ottenuti sono risultati coerenti con le stime ottenute da altri Autori usando metodologie diverse.
XXII Ciclo
1981

Abstract Due to the wide spectrum of turbulent and chemical length- and time scales occurring in a HSDI diesel engine, capturing the correct physics and chemistry underlying combustion poses a tremendous modeling challenge. The processes related to the two-phase flow in a DI diesel engine add even more complexity to the total modeling effort. The Representative Interactive Flamelet (RIF) model has gained widespread attention owing to its ability of correctly describing ignition, combustion and pollutant formation phenomena. This is achieved by incorporating very detailed chemistry for the gas phase as well as the soot particle growth and oxidation, without imposing any significant computational penalty. The model, which is based on the laminar flamelet concept, treats a turbulent flame as an ensemble of thin, locally one-dimensional flame structures, whose chemistry is fast. A potential explanation for the significant underprediction of part load soot observed in previous studies applying the model is the neglect of wall heat losses in the flamelet chemistry model. By introducing an additional source term in the flamelet temperature equation, directly coupled to the wall heat transfer predicted by the CFD-code, flamelets exposed to walls are assigned heat losses of various magnitudes. Results using the model in three-dimensional simulations of the combustion process in a small-bore direct injection diesel engine indicate that the experimentally observed emissions of soot may have their origin in flame quenching at the relatively cold combustion chamber walls.