439 research outputs found
Buletin Pos dan Telekomunikasi: Vol. 12, No. 2, Juni 2014
No full text1. Analisa Tekno Ekonomi Refarming Frekuensi 2100 MHz dengan Analisis Penggantian / Doan Perdana
2. Evaluasi Kinerja IEEE 802.11e HCCA untuk Dukungan QoS pada WLAN Menggunakan NS-2 / Amry Daulat Gultom
3. Analisis Kesuksesan Sistem Informasi Manajemen Sumber Daya dan Perangkat Pos dan Informatika (SIMS) / Awangga Febian Surya Admaja
4. Studi Standardisasi Sertifikat Elektronik dan Keandalan dalam Penyelenggaraan Sistem Transaksi Elektronik / Ahmad Budi Setiawan
5. Studi Penentuan Spesifikasi Teknik Terminal Wideband Code Division Multiple Access (WCDMA) Frekuensi 900 MHz melalui Uji Laboratorium / Sri Ariyanti
6. Proyeksi Jumlah Pelanggan Telepon Bergerak Seluler di Indonesia / Kasmad Ariansya
Laura Doan, Disturbing Practices History, Sexuality and Women’s Experience of Modern War
Get PDFLaura Doan is professor of cultural history and sexuality studies at the University of Manchester (UK). She is the author of Fashioning Sapphism : The Origins of a Modern English Lesbian Culture (2001). Her latest monograph, Disturbing Practices is a thought provoking innovative book that takes us well beyond the central focus presented in the subtitle: History, Sexuality, and Women’s Experience of Modern War. At the same time a history book and a book on the making of history Disturbing Prac..
Convolutional Autoencoder for the Spatiotemporal Latent Representation of Turbulence
No full textTurbulence is characterised by chaotic dynamics and a high-dimensional state space, which make this phenomenon challenging to predict. However, turbulent flows are often characterised by coherent spatiotemporal structures, such as vortices or large-scale modes, which can help obtain a latent description of turbulent flows. However, current approaches are often limited by either the need to use some form of thresholding on quantities defining the isosurfaces to which the flow structures are associated or the linearity of traditional modal flow decomposition approaches, such as those based on proper orthogonal decomposition. This problem is exacerbated in flows that exhibit extreme events, which are rare and sudden changes in a turbulent state. The goal of this paper is to obtain an efficient and accurate reduced-order latent representation of a turbulent flow that exhibits extreme events. Specifically, we employ a three-dimensional multiscale convolutional autoencoder (CAE) to obtain such latent representation. We apply it to a three-dimensional turbulent flow. We show that the Multiscale CAE is efficient, requiring less than 10% degrees of freedom than proper orthogonal decomposition for compressing the data and is able to accurately reconstruct flow states related to extreme events. The proposed deep learning architecture opens opportunities for nonlinear reduced-order modeling of turbulent flows from data.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Aerodynamic
Functional electrospun fibers for responsive coatings and sacrificial templates
Get PDFAccumulated damage can degrade material properties, such as conductivity in batteries, strength in composites, and barrier effectiveness of coatings. Self-healing materials have the ability to repair or prevent further damage autonomously, where and when it occurs. Autonomous repair can increase the lifetime of materials, thereby reducing the economic and environmental impact of material damage and degradation. A successful strategy for designing self-healing materials relies on microencapsulation of liquid healing agents which are dispersed throughout a bulk polymer or coating.
In this work, we explore the use of electrospun core-shell fibers to sequester healing chemistry for protective coatings. In coaxial electrospinning, two immiscible liquids are pumped through the inner (self-protective core) and outer (polymer shell wall) coaxial needles. A high voltage is applied on the needle tips to electrostatically draw out core-shell fibers (submicron size in diameter). We have developed a polysiloxane based coating for steel containing two types of core-shell fibers. When the coating is mechanically damaged, the two fiber types release their liquid core materials to fill the damaged region, crosslink, and restore the protective coating layer. Characterization of fibers and coating include SEM, TEM, confocal fluorescence microscopy, and FTIR. A self-healing system containing amine and epoxy chemistry is also developed and some advantages and limitations of electrospinning are discussed. Development of new coatings synthesized by core-shell electrospinning will provide corrosion protection to metals, thus increasing material lifetime and performance.
Another popular self-healing strategy is using microvasculature. Microvascular systems employ channels to deliver liquid healing agents to damage sites. One method of fabricating microchannels is embedding a degradable fiber into a polymeric matrix or composite and removing the fiber (through chemical or thermal processing) to create a channel. In this research, we study two polymer systems for use as sacrificial templates for developing microvasculature. Poly(lactic acid) and cyclic poly(phthalaldehyde) fibers are electrospun, embedded into epoxy, and thermally or chemically decomposed to remove the fiber and create channels. Characterization of the fibers and their resultant channels include SEM, TGA, and confocal fluorescence microscopy. Successful evacuation and filling of channels with fluid is confirmed for both polymer systems in different epoxy systems. Finally, a frontal ring-opening metathesis polymerization system with Grubbs’ 2nd generation ruthenium catalyst and cyclic poly(phthalaldehyde) is developed, where concurrent polymerization of bulk polymer and decomposition of sacrificial material to produce vasculature is demonstrated.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2019-12-01The student, Thu Doan, accepted the attached license on 2017-11-21 at 18:33.The student, Thu Doan, submitted this Dissertation for approval on 2017-11-21 at 18:34.This Dissertation was approved for publication on 2017-11-22 at 13:33.DSpace SAF Submission Ingestion Package generated from Vireo submission #11749 on 2018-03-13 at 09:55:50Made available in DSpace on 2018-03-13T15:21:09Z (GMT). No. of bitstreams: 3
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Buletin Pos dan Telekomunikasi: Vol. 13, No. 1, Juni 2015
No full text1. Kebutuhan Frekuensi Pita Lebar Untuk Public Protection and Disaster Relief (PPDR) di Indonesia / Diah Yuniarti
2. Strategi Persaingan Operator Telekomunikasi Seluler / Azwar Aziz
3. Pengaruh Literasi dalam Mendukung Kesuksesan PLIK di Bambanglipuro / Mitra Indriani
4. Kajian Strategi Pengamanan Infrastruktur Sumber Daya Informasi Kritis / Ahmad Budi Setiawan
5. Analisis Kelayakan Implementasi Teknologi LTE 1.8 GHz Bagi Operator Seluler di Indonesia / Sri Ariyanti, Doan Perdana
6. Analisis Unjuk Kinerja Aplikasi VOIP Call Android di Jaringan MANET (Mobile Ad Hoc Network) / Ryan Ari Setyawa
Design Considerations for Brushwood Fences Concerning Bathymetry and Fence Locations
No full textWooden fences are nature-based supporting structures to restore mangroves in the Mekong Delta. The hydraulic functioning of wooden fences was studied in previous studies. However, the role of bathymetry in the dissipation and damping of waves by wooden fences has not been studied yet. Thus, in this study, a numerical approach is used to find the effect of the position of fences and the foreshore bathymetry, including two particular slopes of 1/200 and 1/500, on wave damping due to wooden fences. The results show that the bottom slope significantly influences the dissipation of incoming waves, the so-called pre-dissipation, before damping by the wooden fences. Differences in pre-dissipation occur between fence locations along the cross-shore slopes. The higher pre-dissipation takes place for wooden fences closer to the land, as the depth-limited wave height at the fence reduces. The efficiency in wave damping of wooden fences is also increasing as the freeboard is becoming larger for the fence located closer landward.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Coastal EngineeringHydraulic Structures and Flood Ris
PISA:: Recent developments in offshore wind turbine monopile design
No full textThis paper provides a brief overview of the Pile Soil Analysis (PISA) project, recently completed in the UK. The research was aimed at developing new design methods for laterally loaded monopile foundations, such as those supporting offshore wind turbine structures. The paper first describes the background to the project and briefly outlines the key research elements completed. The paper concludes with a brief description of the anticipated impact of the work and describes initiatives that have followed since.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Geo-engineerin
Vietnamese Genealogy as an Informed Source on Fengshui Discourse during the 19th Century: Records of the Doan Family of Huu Thanh Oai near Hanoi
Get PDFThis article attempts to show that the social and political characteristics of Vietnamese fengshui 風水 are truly informed by genealogical sources, which were written by same Confucian scholars as the theoretical texts of fengshui for promoting their ancestors to gain their favor, thus reflecting socio-political reality.
The Doan Family (Đoàn tộc 段族) from Huu Thanh Oai 右淸威 commune, which differs from the widely researched aristocratic elite founders of state politics and rural communities, in that its influence stemmed from its relationship to the Court of Trinh Lords (Trịnh vương phủ 鄭王府) during the 18th century and became the first elite to establish itself through the 19th century state examination system. The Doan family’s genealogy, Đoàn tộc phả 段族譜, was written by a member who had passed the local examination; and for that reason contains no reference to imperial edicts (letters of appointment) or legends regarding the family as pioneering actors in state or village origins. Instead, the Doan family genealogy is designed to strengthen family bonds through fengshui practices, the rich description of which traces the appearance of fengshui in Vietnam at that time.
Đoàn tộc phả informs us of three characteristic features of early modern Vietnamese fengshui, the first of which is that while the original fengshui masters were Chinese “Northern people” (bắc nhân 北人), native Vietnamese fengshui masters gradually appeared, indicating the penetration of fengshui into rural society. It is clear that the work’s author, a Confucian scholarbureaucrat with a rich knowledge of fengshui, desired to use fengshui ideas rooted in his country’s history, not in China’s.
Secondly, each fengshui episode in Đoàn tộc phả is connected to fengshui theory in order to legitimate the history of the Doan family in each era. And finally, Vietnamese fengshui purports that family descendants can gain favor from matrilineal ancestors. Sons-in-law in fact become interested not only in the funeral and memorial services of their wives’ families, but also in the relocation of their mausolea, which shows incorporation of the Southeast Asian custom of bilateral descent in fengshui practices.journal articl
Analisis Kelayakan Implementasi Teknologi LTE 1.8 GHz Bagi Operator Seluler di Indonesia [Feasibility Analysis of LTE 1.8 GHz for Mobile Operators in Indonesia]
Get PDFPeningkatan kebutuhan layanan data mendorong operator telekomunikasi berusaha mengimplementasikan jaringan akses broadband yang lebih handal. Teknologi LTE merupakan salah satu teknologi dengan kecepatan mencapai tiga kali dibanding teknologi HSDPA, sehingga diharapkan dapat memenuhi kebutuhan pelanggan data mobile. Refarming frekuensi 1.8 GHz untuk penerapan teknologi LTE memberikan efisiensi karena tidak perlu membayar BHP lagi untuk menyewa frekuensi baru. Teknologi 2G GSM selama ini juga semakin ditinggalkan, masyarakat di daerah perkotaan cenderung lebih banyak menggunakan layanan data. Sebelum diterapkannya teknologi LTE pada frekuensi 1.8 GHz perlu adanya kajian untuk mengetahui kelayakan teknologi LTE pada frekuensi 1.8 GHz. Penelitian ini bertujuan untuk melakukan cost-benefit analysis implementasi LTE pada frekuensi 1.8 GHz. Metode penelitian menggunakan pendekatan kualitataif yang didukung dengan data kuantitatif. Hasil penelitian menunjukkan bahwa minimal bandiwdth yang diperlukan agar implementasi LTE layak digunakan adalah 15 MHz. Meskipun tanpa Global Frequency Returning, penggunaan bandwidth 10 MHz tidak layak digunakan untuk implementasi LTE. *****The incresing of data demand drives mobile operators to implement more reliable broadband access network. LTE technology has downlink peak rate up to three times than HSDPA, hence it may fulfill the mobile data user requirement. Frequency 1.8 GHz refarming can be implemented to provide efficiency because They do not need to pay licence fee for leasing new frequency. GSM technology will be abandoned since it is not growing anymore. Besides that, dense urban users tend to use data mobile. Before implementing LTE technology on 1.8 GHz frequency, It is necessary to analysis the feasibility such technology. This research used qualitative method supported by quantitative approach. The result of this research showed that minimum bandwidth to implement 1.8 GHz LTE is 15 MHz. Even without Global Frequency Returning, using bandwidth 10 MHz is not feasible.</p
Intrinsic Determination of the Criticality of a Slow–Fast Hopf Bifurcation
No full textThe presence of slow-fast Hopf (or singular Hopf) points in slow-fast systems in the plane is often deduced from the shape of a vector field brought into normal form. It can however be quite cumbersome to put a system in normal form. In De Maesschalck et al. (Canards from birth to transition, 2020), Wechselberger (Geometric singular perturbation theory beyond the standard form, Springer, New York, 2020) and Jelbart and Wechselberger (Nonlinearity 33(5):2364-2408, 2020) an intrinsic presentation of slow-fast vector fields is initiated, showing hands-on formulas to check for the presence of such singular contact points. We generalize the results in the sense that the criticality of the Hopf bifurcation can be checked with a single formula. We demonstrate the result on a slow-fast system given in non-standard form where slow and fast variables are not separated from each other. The formula is convenient since it does not require any parameterization of the critical curve.This work was supported by the bilateral research cooperation fund of the Research Foundation Flanders (FWO) under Grant No. G0E6618N and the Vietnam National Foundation for Science and Technology (NAFOSTED) under Grant No. FWO.101.2020.01.Wynen, J (corresponding author), Hasselt Univ, Dept Math, Hasselt, Belgium.
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