Mos Research Papers - Academia.edu (original) (raw)
Two-dimensional transition metal dichalcogenides have attracted much attention in the field of optoelectronics due to their tunable bandgaps, strong interaction with light and tremendous capability for developing diverse van der Waals... more
Two-dimensional transition metal dichalcogenides have attracted much attention in the field of optoelectronics due to their tunable bandgaps, strong interaction with light and tremendous capability for developing diverse van der Waals heterostructures with other nanomaterials.
""Este libro brinda una introducción a la electrónica en semiconductores –también llamada de estado sólido? para carreras de Ingeniería en electrónica, electricidad, computadoras, comunicaciones, control y sistemas. Provee una... more
""Este libro brinda una introducción a la electrónica en semiconductores –también llamada de estado sólido? para
carreras de Ingeniería en electrónica, electricidad, computadoras,
comunicaciones, control y sistemas. Provee una explicación de los mecanismos de conducción eléctrica en Silicio, que luego se utiliza para el desarrollo de cuatro dispositivos fundamentales de la electrónica actual: el diodo de juntura, el capacitor Metal-Óxido-Semiconductor (MOS), el transistor MOS y el transistor bipolar de juntura.
Esta obra conduce al estudiante a entender el funcionamiento
de cada uno de los dispositivos, partiendo de sus principios
fundamentales y que, a partir de allí, comprenda, en profundidad, los diferentes modelos eléctricos que puede utilizar para representarlo, sus alcances y limitaciones.
El objetivo principal es que el estudiante conozca y sepa emplear los distintos modelos de los dispositivos electrónicos, de acuerdo al rango de amplitud y frecuencia, para su futura utilización en el diseño y análisis de circuitos""
Este libro brinda una introducción a la electrónica en semiconductores -también llamada de estado sólido- para carreras de ingeniería en electrónica, electricidad, computadoras, comunicaciones, control y sistemas. Provee una explicación... more
Este libro brinda una introducción a la electrónica en semiconductores -también llamada de estado
sólido- para carreras de ingeniería en electrónica, electricidad, computadoras, comunicaciones, control y sistemas. Provee una explicación de los mecanismos de conducción eléctrica en Silicio,
que luego se utiliza para el desarrollo de cuatro dispositivos fundamentales de la electrónica actual: el diodo de juntura, el capacitor Metal-Oxido-Semiconductor (MOS), el transistor MOS, y el transistor bipolar de juntura. El libro conduce al estudiante a que entienda el funcionamiento de cada dispositivo, partiendo de sus principios fundamentales, y que a partir de allí, comprenda en profundidad los diferentes modelos eléctricos que puede utilizar para representarlo, sus alcances y limitaciones. El objetivo último es que el estudiante conozca y sepa utilizar los distintos modelos de los dispositivos electrónicos, de acuerdo al rango de amplitud y frecuencia, para su utilización futura en el diseño y análisis de circuitos.
- by Pedro Julian
- •
- Argentina, VLSI, Electronica, Ingeniería
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Druckausgabe Softcover Ladenpreis ▶ *39,99 € (D) | 41,11 € (A) | CHF 50.00 eBook Erhältlich bei Ihrer Bibliothek oder ▶ springer.com/shop Reihe: Veröffentlichungen der Sektion Religionssoziologie der Deutschen Gesellschaft für Soziologie € (D) sind gebundene Ladenpreise in Deutschland und enthalten 7% MwSt; € (A) sind gebundene Ladenpreise in Österreich und enthalten 10% MwSt. Die mit * gekennzeichneten Preise für Bücher und die mit ** gekennzeichneten Preise für elektronische Produkte sind unverbindliche Preisempfehlungen und enthalten die landesübliche MwSt. Programm-und Preisänderungen (auch bei Irrtümern) vorbehalten. Es gelten unsere Allgemeinen Liefer-und Zahlungsbedingungen.
Voice over IP is a major trend in applications for wireless networks, but even so it is not immune to the risks usually related with IP networks. Proposed solutions for VoIP security are already in the market, but these solutions must... more
Voice over IP is a major trend in applications for wireless networks, but even so it is not immune to the risks usually related with IP networks. Proposed solutions for VoIP security are already in the market, but these solutions must take into account the real-time constraint of voice service and their mechanisms should address possible attacks and overhead associated with it. One of these solutions is to use IETF IPSec
to guarantee confidentiality in order to address security design
holes of wireless VoIP networks. This article performs an experimental comparison of the impact of encryption mechanisms on voice speech quality in widely deployed wireless technologies: 802.11 and Bluetooth. Evaluates the upper bound on number of simultaneous VoIP calls which can be placed in a single cell of both networks when security is applied and uses the computational model E-Model to assess quantitatively the quality of service.
- by Edjair Mota
- •
- Voip, VOIP security, Mos, Wlan
^Äëíê~ÅíK Hydrodesulfurization (HDS) and Hydrodearomatization (HDA) of a real Straight Run Gas Oil (SRGO) were investigated over CoMo-S sulfide catalyst in a high-pressure fixed-bed integral reactor. The effect of the key process... more
^Äëíê~ÅíK Hydrodesulfurization (HDS) and Hydrodearomatization (HDA) of a real Straight Run Gas Oil (SRGO) were investigated over CoMo-S sulfide catalyst in a high-pressure fixed-bed integral reactor. The effect of the key process parameters on the quality of product was studied by varying the temperature (200-370 o C), pressure (20 to 50 bar) and space velocity (1 to 4.7h -1 ). Experimental results revealed that HDS,% activity improved up to 81% when the temperature was increased up to 370 o C but reduced to 60% with increase of space velocity up to 4.7 h -1 . It has been also found that the rate of HDA, % activity enhanced up to 40.6% by increasing pressure up to 50 bar. The Cetane index underwent an increase of 1-3 degrees and gravity increased by 1-1.7 o API. The implication of these results on refining industry is that mild hydrotreating of diesel fuels using the single-stage technology will not enable local refineries to produce diesel fuel meeting the current specifications (<15 ppmwt) except with severe/deep once-through desulfurization or twostage once-through desulfurization with or without splitting the first reactor effluent. = hÉóïçêÇëW Diesel fuel; hydrodesulfurization; hydrodearomatization; CoMo-S/ Al2O3 catalyst =^Ä ëíê~âK Penyahsulfuranhidro (dirujuk sebagai HDS) dan penyaharomatikanhidro (dirujuk sebagai HDA) bagi Minyak Mentah Ringan telah dijalankan menggunakan pemangkin sulfida CoMo-S di dalam reaktor integral mangkin padat bertekanan tinggi. Kesan daripada parameterparameter proses utama terhadap kualiti produk telah dikaji dengan mempelbagaikan suhu (200-370 o C), tekanan (20 ke 50 bar) dan halaju ruang (1 hingga 4.7 h -1 ). Keputusan eksperimen menunjukkan, % aktiviti HDS dipertingkatkan sehingga 81% apabila suhu dinaikkan sehingga 370 o C tetapi berkurang sehingga 60% dengan pertambahan halaju ruang sehingga 4.7 h -1 . Selain itu, keputusan juga menunjukkan bahawa kadar % aktiviti HDA dipertingkatkan sehingga 40.6% apabila tekanan dinaikkan hingga mencecah 50 bar. Indeks setana menunjukkan peningkatan 1&2
- by Fawzi Elfghi
- •
- Mos, HDS, Mixed Oxides
Molybdenum Disulfide (MoS 2 ) is a potential low cost, alternative sunlight harvester for a possible replacement of the conventional photovoltaic materials. It is a suitable photovoltaic absorber material mainly due to its optimum optical... more
Molybdenum Disulfide (MoS 2 ) is a potential low cost, alternative sunlight harvester for a possible replacement of the conventional photovoltaic materials. It is a suitable photovoltaic absorber material mainly due to its optimum optical and electrical properties. In this work, we numerically analyze both hetero-junction and homo-junction device structures of MoS 2 by 1D-Solar Cell Capacitance Simulator (SCAPS). Both n-ZnO/n-CdS/p-MoS 2 and n-MoS 2 /p-MoS 2 show the conversion efficiencies above 19%. We also study various window layer materials to optimize the performance of the hetero-junction structure. The analysis includes the device stability as well operating temperature. The analyzed results indicate the feasible fabrication of high efficiency MoS 2 based solar cells.
Efecto de la temperatura. Efecto de Backgate. Transistor PMOS
Ultrathin (0.3−3 nm) metal dichalcogenides exhibit confinement of carriers, evolution of band-structure and photophysical properties with thickness, high on/off rectification (in MoS 2 , WS 2 , and so forth) and high thermal absorption.... more
Ultrathin (0.3−3 nm) metal dichalcogenides exhibit confinement of carriers, evolution of band-structure and photophysical properties with thickness, high on/off rectification (in MoS 2 , WS 2 , and so forth) and high thermal absorption. Here, we leverage the stable sulfur/nobel-metal binding to incorporate highly capacitive gold nanoparticles (Au NPs) onto MoS 2 to raise the effective gate-voltage by an order of magnitude. Functionalization is achieved via both diffusion limited aggregation and instantaneous reaction arresting (using microwaves) with selective deposition on crystallographic edges (with 60°displacement). The electrical, thermal, and Raman studies show a highly capacitive interaction between Au NP and MoS 2 flakes (C Au-MoS2 = 2.17 μF/cm 2), a low Schottky barrier (14.52 meV), a reduced carrier-transport thermal-barrier (253 to 44.18 meV after Au NP functionalization), and increased thermal conductivity (from 15 to 23 W/mK post NP deposition). The process could be employed to attach electrodes to heterostructures of graphene and MoS 2 , where a gold film could be grown to act as an electron-tunneling gateelectrode connected to MoS 2 .
The development of the world capital market and especially in Indonesia from the beginning of 2020 is very gloomy. It happened because since the end of December 2019 the Covid-19 pandemic occurred which caused panic among capital market... more
The development of the world capital market and especially in Indonesia from the beginning of 2020 is very gloomy. It happened because since the end of December 2019 the Covid-19 pandemic occurred which caused panic among capital market players so that the Composite Stock Price Index (JCI) until at the end of March 2020 had fallen by -36.67%. There was a correction of -38,04% for the average share price of 669 issuers. Conditions like this for long-term investors will be an opportunity to buy up shares, while short-term investors or speculators leave the market. The calculation of the intrinsic value of shares in this study uses the Dividend Discount Model (DDM). It will take a sample of 49 companies that distributed dividends regularly during the period 2014 - 2019 and have never suffered a loss. Based on the research results, we can see that there are 42 companies (86%) that are in an undervalued condition, and only seven companies are overvalued (14%). Meanwhile, seen from the Margin of Safety (MOS) using the market price basis as of September 30, 2020, 35 companies are worth buying because their MOS is above 30% and seven companies have MOS less than 30%. Furthermore, from 35 companies that are eligible to be purchased, there are seven companies, namely HMSP, AALI, ASCII, BMRI, BBRI, ITMG and PTBA.
- by IAEME Publication
- •
- Mos, Intrinsic Value, Ddm
In this study, a concatenative text-to-speech system for Turkish is built. The system uses simple techniques and the concatenation units are obtained from the atomic units. This approach is very well suited for Turkish language structure... more
In this study, a concatenative text-to-speech system for Turkish is built. The system uses simple techniques and the concatenation units are obtained from the atomic units. This approach is very well suited for Turkish language structure and it is flexible enough to allow the synthesis of all types texts. The Turkish TTS system is tested considering the naturalness and intelligibility criterion. It is evaluated by using MOS, DRT and CT. Naturalness and intelligibility of the Turkish TTS system is tested by MOS and CT-DRT, respectively. Although the system uses simple techniques, it provides promising results for Turkish TTS, since the selected concatenative method is very well suited for Turkish language structure.
VoIP adalah suatu sistem yang menggunakan jaringan internet untuk mengirimkan data paket suara dari suatu tempat ke tempat lainnya menggunakan perantara protokol IP. Dengan adanya teknologi VoIP biaya telepon bisa lebih murah terutama... more
VoIP adalah suatu sistem yang menggunakan jaringan internet untuk mengirimkan data paket suara dari suatu tempat ke tempat lainnya menggunakan perantara protokol IP. Dengan adanya teknologi VoIP biaya telepon bisa lebih murah terutama untuk berkomunikasi ke luar negeri karena voice dan data menggunakan jaringan yang sama yaitu jaringan internet. VoIP merupakan layanan yang sangat rentan terhadap delay sedangkan jaringan akses yang ada saat ini memberikan delay yang cukup besar untuk VoIP. Salah satu alternatif jaringan yang dapat digunakan untuk mengatasi masalah tersebut adalah dengan memakai teknologi WiMAX karena WiMAX dapat memberikan layanan data berkecepatan hingga 70 Mbps. Dari hasil penelitian diperoleh hasil bahwa nilai one way delay, jitter dan packet loss masih berada pada nilai yang direkomendasikan oleh ITU-T, yaitu nilai maksimum one way delay yang didapat dari pengukuran adalah 159,87 ms, untuk jitter 7,52 ms dan untuk packet loss adalah 3,175 %. One way delay dan packet loss dari hasil pengukuran digunakan untuk mencari nilai MOS yang merupakan nilai kualitas dari VoIP. Rentang nilai MOS yang didapat dari perhitungan yaitu 3,6 sampai 4,2 yang berarti VoIP layak untuk di aplikasikan ke dalam jaringan WIMAX. Sedangkan nilai maksimal throughput bisa mencapai 2,8 Mbps untuk downlink dan 0,575 Mbps untuk uplink. Dari penilitian didapat juga bahwa nilai SQI yang berada di atas nilai standar perangkat akan memberikan nilai SNR yang cukup tinggi, sedangkan semakin tinggi nilai SQI maka nilai RSSI-nya juga semakin besar.
- by hadratul hendra
- •
- RSSI, Wimax, Throughput, Mos
A Steganographic method for embedding textual information in WAV audio is discussed here. In the proposed method each audio sample is converted into bits and then the textual information is embedded in it. In embedding process , first the... more
A Steganographic method for embedding textual information in WAV audio is discussed here. In the proposed method each audio sample is converted into bits and then the textual information is embedded in it. In embedding process , first the message character is converted into its equivalent binary. The last 4 bits of this binary is taken into consideration and applying redundancy of the binary code the prefix either 0 or 1 is used. To identify the uppercase, lower case, space ,and number the control symbols in the form of binary is used. By using proposed LSB based algorithm, the capacity of stego system to hide the text increases. The performance evaluation is done on the basis of MOS by taking 20 samples and comparison of SNR values with some known and proposed algorithm.
Layered semiconductors based on transition-metal chalcogenides usually cross from indirect bandgap in the bulk limit over to direct bandgap in the quantum (2D) limit. Such a crossover can be achieved by peeling off a multilayer sample to... more
Layered semiconductors based on transition-metal chalcogenides usually cross from indirect bandgap in the bulk limit over to direct bandgap in the quantum (2D) limit. Such a crossover can be achieved by peeling off a multilayer sample to a single layer. For exploration of physical behavior and device applications, it is much desired to reversibly modulate such crossover in a multilayer sample. Here we demonstrate that, in a few-layer sample where the indirect bandgap and direct bandgap are nearly degenerate, the temperature rise can effectively drive the system toward the 2D limit by thermally decoupling neighboring layers via interlayer thermal expansion. Such a situation is realized in few-layer MoSe 2 , which shows stark contrast from the well-explored MoS 2 where the indirect and direct bandgaps are far from degenerate. Photoluminescence of few-layer MoSe 2 is much enhanced with the temperature rise, much like the way that the photoluminescence is enhanced due to the bandgap crossover going from the bulk to the quantum limit, offering potential applications involving external modulation of optical properties in 2D semiconductors. The direct bandgap of MoSe 2 , identified at 1.55 eV, may also promise applications in energy conversion involving solar spectrum, as it is close to the optimal bandgap value of single-junction solar cells and photoelechemical devices.
Abstract-VoIP services are getting more and more popular day by day. In order to meet the users demand for such services irrespective of users location requires wide area wireless coverage.To this extent, wireless mesh networks have been... more
Abstract-VoIP services are getting more and more popular day by day. In order to meet the users demand for such services irrespective of users location requires wide area wireless coverage.To this extent, wireless mesh networks have been considered as practical and inexpensive solution.In order to improve the performance of VoIP services, techniques like packet aggregation are done. This paper focuses on finding the effect of packet aggregation on various parameters like aggregation delay, end to end delay and MOS etc. Results obtained through simulations done on Qualnet Simulator concludes that packet aggregation is justified upto a certain extent only as after that most of the users get dissatisfied.
- by Khyati Marwah
- •
- Voip, Mos, Qualnet, WMN
Many researchers have discussed various topics in universal mobile telecommunication system (UMTS) networks: the process of switching from one cell to another for the subscriber and the impact of the quality of the connection during the... more
Many researchers have discussed various topics in universal mobile telecommunication system (UMTS) networks: the process of switching from one cell to another for the subscriber and the impact of the quality of the connection during the transition process, quality of services (QoS), the quality of the uplink and downlink carrier line, the various types of code for the voice transmitted through the Internet, especially the research that discussed voice over internet protocol (VoIP) technology as voice travels from cell to cell in mobile networks, depending on the type of delivery. In this paper, a proposed scenario of a UMTS network was implemented to evaluate the multicellular VoIP movement; the proposed UMTS network was simulated using the OPNET 14.5 simulator. The calculation and analysis of the different parameters of the user while moving from one cell to another with different movement speeds considered, the best mean opinion score (MOS) value (3.19) registered for the scenario (soft handover) comparing with another type of handover (3.00).
We utilize density functional theory to calculate the edge energy and edge stress for monolayer MoS_2 nanoribbons. In contrast to previous reports for graphene, for both armchair and zigzag chiralities, the edge stresses for MoS_2... more
We utilize density functional theory to calculate the edge energy and edge stress for monolayer MoS_2 nanoribbons. In contrast to previous reports for graphene, for both armchair and zigzag chiralities, the edge stresses for MoS_2 nanoribbons are found to be tensile, indicating that their lowest energy configuration is one of compression in which Mo-S bond lengths are shorter than those in a bulk, periodic MoS_2 monolayer. The edge energy and edge stress is found to converge for both chiralities for nanoribbon widths larger than about 1 nm.
The role of an epitaxial growth technique in the performance of metal oxide semiconductor (MOS) devices was investigated. Using a pioneering method like selective epitaxy, the performance and integration of MOS devices found to be... more
The role of an epitaxial growth technique in the performance of metal oxide semiconductor (MOS) devices was investigated. Using a pioneering method like selective epitaxy, the performance and integration of MOS devices found to be improved significantly. It is also seen that epitaxy is essential for realizing modern semiconductor device like FinFETs. The cheap and improved semiconductor structure like vertical MOSFET also required service of epitaxy technique. The stringent control of the epitaxial process was necessary for achieving the superlative performance and desiredstructures.
Efecto de la temperatura. Efecto de Backgate. Transistor PMOS
This paper presents an empirical investigation of the impact of Secure RTP (SRTP) on VoIP calls over wireless networks: 802.11 and Bluetooth. For the purpose of evaluating this impact we developed an analysis tool based on E-Model and... more
This paper presents an empirical investigation of the impact of Secure RTP (SRTP) on VoIP calls over wireless networks: 802.11 and Bluetooth. For the purpose of evaluating this impact we developed an analysis tool based on E-Model and security aspects of SRTP which attempts to determine the balance of quality of service versus security.
This article presents a voice quality measurement tool based on the ITU-T E-Model. Firstly, the ITU-T and ETSI specifications of E-Model are briefly reviewed and some errors found in these documents are pointed. After, a measurement tool... more
This article presents a voice quality measurement tool based on the ITU-T E-Model. Firstly, the ITU-T and ETSI specifications of E-Model are briefly reviewed and some errors found in these documents are pointed. After, a measurement tool based on the
corrections is described. VoIP calls through the Brazilian National Education and Research Network (RNP) backbone were used to verify the tool operation.
- by José Neuman Souza and +1
- •
- Multimedia Communications, Voip, QoS, Mos
The present work proposes an adaptive solution to provide quality of service in Voice over IP communications. This solution is based on three components that interact in order to achieve higher quality in voice communication. The first... more
The present work proposes an adaptive solution to provide quality of service in Voice over IP communications. This solution is based on three components that interact in order to achieve higher quality in voice communication. The first two consist in changing the codec and the transport protocol in real-time during a conversation; the third consists in using a Forward Error Correction mechanism to recover from loss packets. To demonstrate the voice quality obtained by this solution, a VoIP client application was developed, compatible with other VoIP clients, to implement the proposed quality of service algorithm and control the voice quality during a conversation. The results of the experimental measurements and simulations performed demonstrate that this solution is viable and significantly increases the voice quality of VoIP communication.
- by Mario Nunes
- •
- Voip, QoS, Mos, SIP
We review vibrational and electronic properties of single and a few layer MoS 2 relevant to understand their resonant and non-resonant Raman scattering results. In particular, the optical modes and low frequency shear and layer breathing... more
We review vibrational and electronic properties of single and a few layer MoS 2 relevant to understand their resonant and non-resonant Raman scattering results. In particular, the optical modes and low frequency shear and layer breathing modes show significant dependence on the number of MoS 2 layers. Further, the electron doping of the MoS 2 single layer achieved using top-gating in a field effect transistor renormalizes the two optical modes A 1g and E 1 2g differently due to symmetry-dependent electron-phonon coupling. The issues related to carrier mobility, the Schottky barrier at the MoS 2-metal contact pads and the modifications of the dielectric environment are addressed. The direct optical transitions for single layer-MoS 2 involve two excitons at K-point in the Brillouin zone and their stability with temperature and pressure has been reviewed. Finally, the Fermi-level dependence of spectral shift for a quasiparticle, called trion, has been discussed.
- by Achintya Bera
- •
- Mos
As environmental regulations increase, more selective transition metal sulfide (TMS) catalytic materials for hydrotreating applications are needed. Highly active TMS catalysts become more and more desirable triggering new interest for... more
As environmental regulations increase, more selective transition metal sulfide (TMS) catalytic materials for hydrotreating applications are needed. Highly active TMS catalysts become more and more desirable triggering new interest for unsupported Co-promoted ...
The effect of annealing temperature on the properties of c-Si wafer/SiO x interface (x = 1.15 and 1.3) is studied by Transmission Electron Microscopy and Capacitance/Conductance-Voltage measurements. Furnace annealing for 60 min at 700... more
The effect of annealing temperature on the properties of c-Si wafer/SiO x interface (x = 1.15 and 1.3) is studied by Transmission Electron Microscopy and Capacitance/Conductance-Voltage measurements. Furnace annealing for 60 min at 700 and 1000 o C is used to grow amorphous or crystalline Si nanoparticles. The high temperature process leads to an epitaxial overgrowth of the Si wafer and an increase of the interface roughness, 3-4 monolayers at 700 o C and 4-5 monolayers at 1000 o C. The increased surface roughness is in correlation with the higher density of electrically active interface states.
- by Benjamin Valdez Salas and +3
- •
- Nanotechnology, Nanoscience, TEM, Mos
System does not own arrangement to traffic passing through it, all packets assumed equal. If VOIP packets queue up together with data packet at this system hence the delay yielded will be very big. A correct queue method needed to improve... more
System does not own arrangement to traffic passing through it, all packets assumed equal. If VOIP packets queue up together with data packet at this system hence the delay yielded will be very big. A correct queue method needed to improve network delay characteristic and improve Quality of Service (QOS) of VoIP. One QOS management method on VoIP which can be used is CBQ (Class Based Queuing) queue method. CBQ represent scheduling mechanism providing link-sharing among classes using same physical link. This is the method enable division of bandwidth allocation from router output port as according to traffic type and priority. In the event of congestion, traffic with high priority will accept minimum bandwidth allocations as which have previous reservation. At the simulated scenario and network topology, CBQ queue method able to meet the requirement of maximum delay according to ITU recommendation G.114. Based on calculation conversion R factor value to MOS by using E-Model, CBQ can assign MOS value more than 4 (four), meaning its value is good. So that VoIP service is competent to be implemented.
Interactive video services, like video telephony, social TV or on-line gaming, are about to become a significant part of the service portfolio for telecommunication service providers. As the future commercial success of these services... more
Interactive video services, like video telephony, social TV or on-line gaming, are about to become a significant part of the service portfolio for telecommunication service providers. As the future commercial success of these services will depend essentially on their end-to-end quality as perceived by the end user, appropriate Quality-of-Experience (QoE) measurement methods are of paramount importance. The aim of this paper is to provide an application-oriented re-evaluation of actual QoE metrics for these services and to design a test methodology for evaluating user perceived experience which goes beyond standard Mean Opinion Score (MOS) metrics. To this end, we describe a specific test scenario designed for assessing the currently recommended question sets from two ITU recommendations. We determine the goodness of fit of these question sets to the user perceived quality dimension. Altogether, the resulting reduced set of items (questions) provides a significant step towards a more realistic methodology for assessing audio-visual quality perception.
- by Peter Reichl and +1
- •
- Mos, Conversational Interactivity, Speech quality, Test Methodology
Nickel–MoS2 composite coatings were obtained by electrodeposition from a nickel electrolyte containing suspended MoS2 particles. The coating composition, morphology, crystalline structure, microhardness, and frictional behavior were... more
Nickel–MoS2 composite coatings were obtained by electrodeposition from a nickel electrolyte containing suspended MoS2 particles. The coating composition, morphology, crystalline structure, microhardness, and frictional behavior were studied as a function of MoS2 concentration. The results obtained in this study revealed that the codeposited lubricant particles strongly influenced the composite nickel coating properties. It was found that increasing codeposited MoS2 decreases the average grain size of nickel crystallites and leads to the formation of clusters which, in turn, lead to rough coatings with a high and variable thickness. The results of tribological response indicated that the reduction of friction coefficient and the improvement of wear resistance were performed until an optimal value of MoS2 concentration, which provided the best condition that promoted the tribo-layer stability and maintained the matrix integrity. A comparison of tribological and micromechanical propert...
Although extensive knowledge has rapidly developed in the synthesis and processing of silicon quantum dots (zero-dimensional) and silicon nanowires (one-dimensional), the twodimensional (2D) allotropic form of silicon has been hardly... more
Although extensive knowledge has rapidly developed in the synthesis and processing of silicon quantum dots (zero-dimensional) and silicon nanowires (one-dimensional), the twodimensional (2D) allotropic form of silicon has been hardly accessed and only recently few attempts have targeted 2D silicon nanosheets (NSs) akin to graphene. In this context, a 2D honeycomb crystalline form of silicon, the so-called "silicene", has recently afforded great appeal as a novel graphene-like material. [ 1-11 ] Until now, free standing silicene has never been observed, because a 2D sp 2 Si crystal is chemically unstable in ambient conditions. [ 4 ] Nevertheless, quasi-2D honeycomb Si layers grown by molecular beam epitaxy (MBE) can be stabilized by a supporting substrate, as shown in recent pioneering experiments. [ 5 ] To date, buckled silicene structures have been experimentally reported on substrates with metallic character, including Ag(111), [ 6-8 ] Ir(111), [ 9 ] and ZrB 2. [ 10 ] However, accessing the electronic functionalities of the silicene necessarily demands to bypass of the metallic support. The purpose of this paper is to look for a non-metallic substrates which can concomitantly favor a local 2D growth of Si with hexagonal crystal symmetry. To this scope, layered graphite-like materials [ 12 ] with hexagonal atomic arrangement are expected to be promising candidates. Importantly, cleavage of the layered compounds does not create dangling bonds and, therefore, these materials are ideally suited as inert substrates for van der Waals epitaxy of weakly interacting fi lms in the monolayer regime. [ 13-15 ] The electronic properties as well as the structural and chemical characteristics of layered materials make them appealing for a variety of applications and suitable for the synthesis of hybrid devices based on 2D materials. [ 16-18 ]
Analogue speech signal is one of the most natural means used by humans for communication purposes. The emergence of digital modulation and coding techniques has made the transmission of analogue speech (as digital content) over various... more
Analogue speech signal is one of the most natural means used by humans for communication purposes. The emergence of digital modulation and coding techniques has made the transmission of analogue speech (as digital content) over various conduits possible, albeit with inevitable signal degradation as a result of errors inherent in the conversion process. A need naturally arises for determining the quality of speech received at the information sink, with a view to enhancing its robustness to degradation suffered in transit over the communication channel. We present in this paper analytic methods of qualitative assessment of the quality of recovered digitally transmitted speech. A methodology for determining the intelligibility of speech by using segmental SNR gotten by dividing the speech signal into M integer segments is proposed. This methodology has the following advantages: a) it allows for assessing the dynamics of change of speech quality in real-time through statistical modeling, b) it obviates the need for expensive, yet subjective experimental approaches like MOS, and c) it takes into consideration not only the signal power, but also its spectral characteristics which is a step above the use of Modulated Noise Reference Units (MNRUs). Using the obtained results, a procedure for analysis of speech intelligibility by means of statistical modeling is developed.
- by Adeyemi alatishe
- •
- Speech Processing, Mos, PCM, SNR
Speech quality evaluation is one of the fundamental aspects of telecommunications which has been frequently discussed since the inception of Internet telephony. Voice services providers should ensure adequate connection quality to end... more
Speech quality evaluation is one of the fundamental aspects of telecommunications which has been frequently discussed since the inception of Internet telephony. Voice services providers should ensure adequate connection quality to end users. Using speech quality evaluation, they try to identify possible issues and to prevent service quality degradation as early as when the network is being designed. This article focuses on a non-intrusive method of speech quality evaluation in accordance with ITU-T recommendation G.107, known as the E-model. Real measurements that were carried out depending on codec tandeming in the communication system and causing the packet loss in IP telephony differed from results obtained using the PESQ method. This lead the authors to carry out an experiment in which the given scenario would be measured, its results assessed and a correction function that would fine-tune the E-model for tandeming was drafted.
The surface morphology and phase composition of the coatings obtained by magnetron sputtering of Cu-MoS2 composite targets have been studied by X-ray diffraction, scanning electron microscopy and X-ray spectral microanalysis. X-ray... more
The surface morphology and phase composition of the coatings obtained by magnetron sputtering of Cu-MoS2 composite targets have been studied by X-ray diffraction, scanning electron microscopy and X-ray spectral microanalysis. X-ray diffraction studies of coatings show presence of two crystalline phases, namely Cu with face-centered cubic lattice and CuMo6S8 with a rhombohedral lattice. Studies of the surface morphology in Cu-CuMo6S8 coatings revealed two types of structures. One of the structures is realized in the form of globular formations, while the second is similar to the structure that had single-component Cu coating. X-ray spectral microanalysis showed that globular formations have higher Mo and S contents in comparison with other type of surface structure. The ratio between these elements is close to that in CuMo6S8. However, the Cu content is many times higher than the calculated amount for this compound. This suggests that globular formations are heterostructural where on...
Lithium niobate is the archetypical ferroelectric material and the substrate of choice for numerous applications including surface acoustic wave radio frequencies devices and integrated optics. It offers a unique combination of... more
Lithium niobate is the archetypical ferroelectric material and the substrate of choice for numerous applications including surface acoustic wave radio frequencies devices and integrated optics. It offers a unique combination of substantial piezoelectric and birefringent properties, yet its lack of optical activity and semiconducting transport hamper application in optoelectronics. Here we fabricate and characterize a hybrid MoS2/LiNbO3 acousto-electric device via a scalable route that uses millimetre-scale direct chemical vapour deposition of MoS2 followed by lithographic definition of a field-effect transistor structure on top. The prototypical device exhibits electrical characteristics competitive with MoS2 devices on silicon. Surface acoustic waves excited on the substrate can manipulate and probe the electrical transport in the monolayer device in a contact-free manner. We realize both a sound-driven battery and an acoustic photodetector. Our findings open directions to non-inva...
A sensor based on Pd/SiO 2 /Si MOS capacitor was fabricated on p type <100> (1-6 ΩCm) Si with thermal oxide layer of thickness about 200 A˚. The sensor showed sensitivity to Xyelene (C 8 H 10) vapour and was characterized at Xyelene... more
A sensor based on Pd/SiO 2 /Si MOS capacitor was fabricated on p type <100> (1-6 ΩCm) Si with thermal oxide layer of thickness about 200 A˚. The sensor showed sensitivity to Xyelene (C 8 H 10) vapour and was characterized at Xyelene concentrations ranging from (500ppm-16,000ppm) at different operating temperatures (room temperature,70˚C and 120˚C), in air. It was found that sensitivity of the sensor was maximum at an operating temperature of 70˚C. Keywords-MOS (metal-oxide-semiconductor) structure, gas sensor, Palladium (Pd), sensitivity, C-V and G-V characteristics.