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Carrier confinement effect enhanced by AlGaN/GaN multi-quantum barrier in AlInGaN based high power blue-violet laser diodes

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Physica Status Solidi (C) Current Topics in Solid State Physics 2006年第6期3卷 2215-2218页

作者： Lee, Sung-Nam Cho, S.Y. Ha, K.H. Choi, K.K. Jang, T. Chae, S.H. Kim, H.K. Paek, H.S. Sung, Y.J. Sakong, T. Son, J.K. Ryu, H.Y. Kim, Y.H. Yoon, E. Nam, O.H. Park, Y. Photonics Program Team Samsung Advanced Institute of Technology Suwon Korea Republic of Communication Module Lab. Samsung Electronics Suwon Korea Republic of CSEL School of Materials Science and Engineering Seoul National University Seoul Korea Republic of

AlGaN/GaN multi-quantum barriers (MQBs) were firstly introduced into violet AlInGaN laser diodes with InGaN multi-quantum wells structure, resulting in drastic improvements in lasing performance. Comparing with conventional AlGaN single electron blocking layer (EBL), lower threshold current and higher slope efficiency at room temperature could be achieved by AlGaN/GaN multiquantum barrier. It can be explained that p-type AlGaN/GaN MQBs is more effective to suppress the overflow of electron than single p-type AlGaN EBL by the increase of effective barrier heights due to the quantum effect of MQB and the enhancement of p-type doping efficiency. Additionally, the strain effect in InGaN multi-quantum wells (MQWs) from single p-type AlGaN EBL can be reduced by forming the AlGaN/GaN super lattice structure. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

关键词： Aluminum gallium nitride

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Low loss LTCC passive transmission line at Millimeter-wave frequency

Low loss LTCC passive transmission line at Millimeter-wave f...

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Asia-Pacific Conference on Applied Electromagnetics, APACE

作者： Mohd Fadzil Amiruddin Salizul Jaafar Suhandi Bujang Azzemi Ariffin Azlan Sulaiman Noor Aisyah Mohd Akib Young Chul Lee System Technology Program TM Innovation Centre TM Research and Development Sdn. Bhd. Cyberjaya Selangor Darul Ehsan Malaysia Division of Marine Electronics and Communication Engineering Mokpo National University Mokpo Jeonnam South Korea

60 GHz band has advantages in terms of broadband, frequency reuse, dimension of circuit, size of layout, and power. A wide bandwidth available in 60 GHz band is ideal for the high data rate transmission. It is also advantage of 60 GHz band that the passive circuit can be made very small. Due to those advantages, this band now is applied to Millimeter-wave (MM-wave) video transmission, outdoor and indoor wireless system, wireless Gigabit Ethernet link, and 60 GHz wireless LAN application. A low temperature co-fired ceramic (LTCC) becomes a technology of choice when it comes to MM-wave band. However, LTCC shows several issues on integration of MM-wave circuits such as; attenuation, resonance and isolation of passive circuits. This paper described the design techniques for an efficient low loss LTCC passive transmission lines. LTCC passive transmission line was design in the 6-layers of LTCC dielectric substrate, using Advance System Design (ADS) and Computer Simulation Technology (CST) for EM simulation. Analysis and measurement of transmission lines using different substrate height of 100 μm and 114 μm was also presented. The proposed structure is validated by full-wave simulation, and experimental measurements. The analyses of fabricated modules with 100 μm and 114 μm shows the passive transmission lines achieved the insertion loss less than -1dB and return loss less than -10dB.

关键词： Coplanar waveguides Transmission line measurements Substrates Power transmission lines Propagation losses Resonant frequency Dielectric measurements

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Data Warehouse-Based Ad Archive for Media Analysis

Data Warehouse-Based Ad Archive for Media Analysis

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International Conference on Edge Computing and Applications (ICECAA)

作者： G. Indra B. Praveen Kumar G. Hemanth Kumar MS Srikanth Department of Computer Science and Engineering R.M.K. College of Engineering and Technology Chennai Tamil Nadu India Department of Computer Science and Engineering KL University Vijayawada Andhra Pradesh India School of Electronics and Communication Engineering REVA University Bengaluru Karnataka India Program Specialist TNS India Foundation Bangalore Karnataka India

Media influence's public opinion and decision-making today. Advertisements especially affect audience perceptions, actions, and purchases. A comprehensive data library on commercials and their performance is needed to understand how media affects society. Ad content, placement, and performance are stored in a data warehouse-based ad archive. The archive can evaluate marketing campaigns and discover media trends. Ad servers, social media platforms, and media monitoring tools may build the data warehouse-based ad archive. A dimensional data model helps retrieve and analyze data. Structured Query Language (SQL) queries, Online Analytical Processing (OLAP) cubes, and data visualization tools may access the archive. Media academics, marketers, and politicians may study the media environment using the data warehouse-based ad archive. Media academics may utilize the collection to study the marketing campaigns, media trends and media's influence on society. The archive may help advertisers analyze their ad campaigns, optimize media placement, and understand their target demographic. Policymakers may use the archive to monitor media outlets' advertising compliance and assess policy changes' media landscape effects.

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Modified Turnstile Antenna Design for Multi-Band and Broadband Applications

Modified Turnstile Antenna Design for Multi-Band and Broadba...

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USNC-URSI Radio Science Meeting (Joint with AP-S Symposium)

作者： I-Fong Chen Chia-Mei Fei-Lung Wu Jian-An Xie Dept. of Computer and Communication School of Electronics and Electrical Engineering Dongguan Polytechnic Jinwen University of Science and Technology New Taipei City Taiwan Department of Communications Engineering Feng Chia University Taichung City Taiwan Ph.D. Program of Electrical and Communications Engineering Feng Chia University Taichung City Taiwan

ISBN: (数字)9789463968119

ISBN: (纸本)9798350359497

The proposed antenna with a size of 90 mm x 90 mm, and the ground portion is 64 mm x 64 mm, which material is FR4 glass epoxy substrate with the thickness of 1.6 mm, relative permittivity of 4.3 and loss tangent of 0.023, consists of four modified dipole elements and four power dividers, as shown in Figure. 1. For the multi-band and broadband operation, three dipole antennas were shunted to be a dipole element. The electrical-length of the dipole element can be determined from the one quarter-wave length at the 2.45 GHz, 5.5 GHz and 6.525 GHz, for covering 2400 MHz-2500 MHz, 5150 MHz-5850 MHz and 5925 MHz-7125 MHz. In order to operates in various modes such as normal mode and axial mode, the modified four port triple-band microstrip series power divider was designed. In normal mode, it radiates horizontally polarized waves where as in axial mode, it radiates circularly polarized waves. The radiated patterns of the proposed antenna as shown in Figure. 2. The features of the proposed antenna are shown in the Table I. Impressive radiated gains and efficiencies are obtained.

关键词： Power dividers Dipole antennas Conferences Glass Broadband communication Broadband antennas Microstrip

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Multicharged optical vortices induced in a dissipative atomic vapor system

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Physical Review A 2013年第1期88卷 013847-013847页

作者： Yiqi Zhang (张贻齐) Milivoj Belić Zhenkun Wu (吴振坤) Chenzhi Yuan (袁晨智) Ruimin Wang (王瑞敏) Keqing Lu (卢克清) Yanpeng Zhang (张彦鹏) Key Laboratory for Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Information Photonic Technique Xi'an Jiaotong University Xi'an 710049 China Science Program Texas A&M University at Qatar P.O. Box 23874 Doha Qatar School of Information and Communication Engineering Tianjin Polytechnic University Tianjin 300160 China

We investigate numerically the dynamics of optical vortex beams carrying different topological charges, launched in a dissipative three-level ladder-type nonlinear atomic vapor. We impose the electromagnetically induced transparency (EIT) condition on the medium. Linear, cubic, and quintic susceptibilities, considered simultaneously with the dressing effect, are included in the analysis. Generally, the beams slowly expand during propagation and new vortices are induced, commonly appearing in oppositely charged pairs. We demonstrate that not only the form and the topological charge of the incident beam but also its growing size in the medium greatly affect the formation and evolution of vortices. We formulate common rules for finding the number of induced vortices and the corresponding rotation directions, stemming from the initial conditions of various incident beams, as well as from the dynamical aspects of their propagation. The net topological charge of the vortex is conserved during propagation, as it should be, but the total number of charges is not necessarily the same as the initial number, because of the complex nature of the system. When the EIT condition is lifted, an enhancement region of beam dynamics is reached, in which the dynamics and the expansion of the beam greatly accelerate. In the end, we discuss the liquid-like behavior of light evolution in this dissipative system and propose a potential experimental scheme for observing such a behavior.

关键词： MULTIPLY charged ions OPTICAL vortices ENERGY dissipation VAPORS ELECTROMAGNETISM OBSERVATION (Scientific method)

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Hyperspectral band referencing based on correlation structure

Hyperspectral band referencing based on correlation structur...

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IEEE International Conference on Control System, Computing and engineering (ICCSCE)

作者： Ayman Mahmoud Ahmed Salwa ElRamly Mohamed El. Sharkawy Egyptian Space Program National Authority for Remote Sensing and Space Sciences Cairo Egypt Egyptian Space Program National Authorty for Remote Sensing and Space science Cairo Egypt Department of Electronics and Communication Engineering Ain-Shams University Cairo Egypt E-JUST–Egypt-Japan University of science and technology Alexandria Egypt

Hyperspectral imaging has been widely studied in many applications; notably in climate changes, vegetation, and desert studies. However, such kind of imaging brings a huge amount of data, which requires transmission, processing, and storage resources for both airborne and space borne imaging. Compression of hyperspectral data cubes is an effective solution for these problems. Lossless compression of the hyperspectral data usually results in low compression ratio, which may not meet the available resources; on the other hand, lossy compression may give the desired ratio, but with a significant degradation effect on object identification performance of the hyperspectral data. Moreover, most hyperspectral data compression techniques exploits the similarities in spectral dimensions; which requires bands reordering or regrouping, to make use of the spectral redundancy. In this paper, we analyze the spectral cross correlation between bands for AVIRIS and Hyperion hyperspectral data; spectral cross correlation matrix is calculated, assessing the strength of the spectral matrix, and finally, we propose new technique to find highly correlated groups of bands in the hyperspectral data cube based on “inter band correlation square” referencing.

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Any Bluetooth device can be hacked. Know how?

Cyber Security and Applications

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Cyber Security and Applications 2024年 2卷

作者： Muraleedhara, Prathibha Christo, Mary Subaja J, Jaya Yuvasini  D College of Technology – Information Security and Program Management University of Houston 77204 TX United States Department of Networking and Communication School of Computing SRM Institute of Science and Technology Kantankulathur Chennai India Department of Electronics and Communication Engineering Hindustan College of Engineering and Technology India Assistant Professor Department of Computer Science and Business Systems Thiagarajar College of Engineering Madurai 625015 India

In today's world, Bluetooth technology is integrated into almost every device we use, from wireless headsets, mice, and keyboards to cars and smart home devices. But with the convenience of this technology comes the risk of privacy and security breaches. Each Bluetooth device has potential vulnerabilities that cybercriminals can exploit and take advantage of. It is important to create awareness about various Bluetooth vulnerabilities, exploits, and ways to prevent them. This article examines the dark side of Bluetooth technology by explaining how hackers can find ways to bypass the advanced security features of laptops, phones, cars, or smart home devices to compromise the devices and steal personal sensitive data. Whether it is a casual user of Bluetooth technology or a business owner with multiple devices, understanding these risks is crucial to protecting yourself and your information. This article begins by explaining the basics of Bluetooth technology and how it works. Followed by a list of security risks involved while using Bluetooth and finally, it highlights the best practices to protect the devices and the data they contain. © 2024

关键词： Ad hoc networks and security risk Bluetooth Exploit Threat Vulnerability

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Ultra-Reliable Device-Centric Uplink communications in Airborne Networks: A Spatiotemporal Analysis

arXiv

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arXiv 2023年

作者： Nabil, Yasser ElSawy, Hesham Al-Dharrab, Suhail Attia, Hussein Mostafa, Hassan Department of Electronics and Communication Engineering Cairo University Giza12613 Egypt School of Computing Queen’s University KingstonON Canada Dhahran31261 Saudi Arabia University of Science and Technology Nanotechnology and Nanoelectronics Program Zewail City of Science and Technology Giza12578 Egypt

This paper proposes an ultra-reliable device-centric uplink (URDC-UL) communication scheme for airborne networks. In particular, base stations (BSs) are mounted on unmanned aerial vehicles (UAVs) that travel to schedule UL transmissions and collect data from devices. To attain an ultra-reliable unified device-centric performance, the UL connection is established when the UAV-BS is hovering at the nearest possible distance from the scheduled device. The performance of the proposed URDC-UL scheme is benchmarked against a stationary UAV-centric uplink (SUC-UL) scheme where the devices are scheduled to communicate to UAV-BSs that are continuously hovering at static locations. Utilizing stochastic geometry and queueing theory, novel spatiotemporal mathematical models are developed, which account for the UAV-BS spatial densities, mobility, altitude, antenna directivity, ground-to-air channel, and temporal traffic, among other factors. The results demonstrate the sensitivity of the URDC-UL scheme to the ratio between hovering and traveling time. In particular, the hovering to traveling time ratio should be carefully adjusted to maximize the harvested performance gains for the URDC-UL scheme in terms of link reliability, transmission rate, energy efficiency, and delay. Exploiting the URDC-UL scheme allows IoT devices to minimize transmission power while maintaining unified reliable transmission. This preserves the device’s battery and addresses a critical IoT design challenge. Copyright © 2023, The Authors. All rights reserved.

关键词： Internet of things

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Computer-controlled equipment testing: Speed, accuracy and improved analysis

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NAVAL ENGINEERS JOURNAL 1998年第1期110卷 207-215页

作者： Smith, JJ Greene, WC John J. Smith is a senior field engineer with the Electrmics Systems Division (ESD) of TRACOR System Technologies Inc. As the technical supervisor fm the Impact and Feasibility Studies group of the E nginemang Department he provides engineering support to the Ships Communication Systems Operation Branch Naval Air Warfare Center Aircraft Division Patuxent River St. Inigoes Maryland. This support entails the integration of radio communication systems on USS Arleigh Burke (DDG 51)-class AEGIS destrqvers and special engineering projects. During 23 years of Naval service as an electronics technician he sewed as electronics division officer for the repair division (R-4) on board USS Ghore (AS IS) homeported in La Maddalena Sardinia. His last duty station was NAVCOMSTA Roosevelt Road Puerto Rico where he sewed as muster chief-in-charge of electronic communications repair the island-wide communications quality control chiel the contract administrator to the operations and maintenance contractor supporting Mystic Star transmitter and receiver facilities for Air Fme One communications the Naval transmitter station and 16 interconnecting remote mimowave sites. Wilhemina C. Greene is a Supervisory Electronics Engineer with the Combatant Engineering and Integration Section at NAWCAD. As the team leader directs the effots of Civilian and contractors personnel responsible for delivering a fully integrated and tested Radio Communication Systems for surfme cmnbatant ships. The team also pvovida the Nay's only system level training on RCS for all AEGIS Pre-Communits. As part ofthis eflort she is responsible for the operation and maintenance of the Satellite Production Test Centq a facility housing the RCS test beds. Ms. Greene has over 20 years of government service 13 years on the AEGIS RCS program. She has a BSEE degree from Tennessee State University.

As shipboard radio communication systems (RCSs) become more complex and crew size continues to be reduced, the requirement for an automated, condition-based maintenance system is imperative. Personal computers can be programmed to provide full equipment testing that is capable of digital interface as well as automated and semi-automated testing of equipment that is not buss-controllable. Some of the advantages of computer-controlled equipment testing (CCET) include increased accuracy repeatability, and data-collection capability for in-depth analysis. However, the paramount advantage of CCET is speed. This paper will describe various methods of remote testing, including using a LAN, the Internet, and the telephone system. It will detail application software developed to test the Aegis-class destroyers' RCS equipment. This paper examines CCET as it is presently applied to the Aegis Board of Inspection and Survey (INSURV) support program. Additionally, the condition-based maintenance (CBM) application developed for over-the-air system testing of the Navy's UHF line-of-sight (LOS) system installed on the USS Yorktown (CG 48) as part of the Smart Ship project will be described. This paper will also describe CCET methods to use charged-coupled device (CCD) miniature cameras to read analog meters, gauges, or entire gauge boards.

关键词： Electronic ship equipment

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Sensory Perception of Haptic Rendering in Surgical Simulation

Sensory Perception of Haptic Rendering in Surgical Simulatio...

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International Conference on Computing and Networking Technology (ICCNT)

作者： Rohit Kaushik Rachit Sachdeva Chirag Vashisht Krishan Kant Choudhary CS and Mathematics Department Data Analytics Program University of Illinois Springfield USA Electronics and Communication Engineering Department Dr. Akhilesh Das Gupta Institute of Technology and Management New Delhi India Information Technology and Engineering Department Dr. Akhilesh Das Gupta Institute of Technology and Management New Delhi India

The essential ideas behind haptic technology, including haptic interface and haptic rendering methods, as well as its application to surgical simulation, medical education, and other diverse topics, are presented in this paper. In empirical psychology and physiology, this refers to the sense of contact. The process of analyzing and developing capabilities in response to user interactions with virtual entities is elaborated as haptic rendering. Haptic may indicate haptic transmission, haptic perception, and haptic technology. Humans and other animals can respond to one another by using their feelings through haptic technology. Haptic perception is the process of recognizing objects through *** implies tactile response, which means it delivers feedback in the state of sensation as we may sense the material properties and motions of virtual objects devised by a computer. The use of haptic technology in the medical profession has proven extremely beneficial, and it has a wide range of applications in many different industries. Providing effective exchange via virtual reality helps to ease the surgeon’s obligations. Amplify a person’s experience in the virtual environment. The haptics ability ranges from computer graphics to psychophysics, cognitive science, and neurosciences.

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