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- Amplifier (4)
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- Small Spacecraft (3)
- Wireless Networks (3)
- Balanced LNA (2)
- Balanced amplifier (2)
- COLLECTOR (2)
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- Eavesdropping (2)
- SMART GRID (2)
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- Security of Wireless Networks (2)
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- Bat Syllable; Bayesian Analysis; Chirp/ Data Registration; Functional Data Analysis; Functional Mixed Model; Isomorphic Transformation; Nonstationary Time Series; Registration (1)
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Articles 1 - 30 of 30
Full-Text Articles in Systems and Communications
Openorbiter Ground Station Software, Alexander Lewis, Jacob Huhn, Jeremy Straub, Travis Desell, Scott Kerlin
Openorbiter Ground Station Software, Alexander Lewis, Jacob Huhn, Jeremy Straub, Travis Desell, Scott Kerlin
Jeremy Straub
OpenOrbiter is a student project at the University of North Dakota to design and build a low cost1 and open-hardware / open-source software CubeSat2. The Ground Station is the user interface for operators of the satellite. The ground station software must manage spacecraft communications, track its orbital location , manage task assignment, provide security and retrieve the data from the spacecraft. This will be presented via a graphical user interface that allows a user to easily perform these tasks.
Work On A Software Defined Radio (Sdr) For A Cubesat-Class Spacecraft, Michael Wegerson, Jeremy Straub, Sima Noghanian
Work On A Software Defined Radio (Sdr) For A Cubesat-Class Spacecraft, Michael Wegerson, Jeremy Straub, Sima Noghanian
Jeremy Straub
A Software Defined Radio (SDR) will be used for OpenOrbit-er satellite to ground communications. The use of SDR al-lows for a smaller, more versatile radio then what a stand-ard hardware radio can provide; perfect for the unpredicta-ble environment Open Orbiter will be exposed to. Current implementation uses a simple $20 USB TV decoder for the receiver and the open-source program GNU Radio for soft-ware decoding. Broadband FM transmissions have been re-ceived and decoded successfully and on-going experimen-tation for receiving satellite communications are yielding promising results.
Pre-Amplifiers For A 15-Tesla Magnetic Resonance Imager, Chin-Leong Lim, Peter Serano, Jerome L. Ackerman
Pre-Amplifiers For A 15-Tesla Magnetic Resonance Imager, Chin-Leong Lim, Peter Serano, Jerome L. Ackerman
Chin-Leong Lim
High-field magnetic resonance imagers (MRI) give better signal-to-noise ratio (SNR) and image contrast. However clinical MRIs are currently limited to 3 Tesla (T) magnetic field strength. To create an uncommon 15 T scanner for research use, we evaluated several low-cost, intended for wireless communication, GaAs enhancement-mode pseudomorphic high electron mobility transistors (ePHEMT) in the critical preamplifier slot. This paper reports the experimental results that were obtained at both module and system levels. When evaluated in our prototype 15 T scanner front-end’s preamplifier slot, the candidate devices’ sub 1dB noise figures enabled image SNR ~ 110 in a water phantom (test …
Limiting And Transient Performances Of A Low Loss Pin-Schottky Limiter, Chin-Leong Lim
Limiting And Transient Performances Of A Low Loss Pin-Schottky Limiter, Chin-Leong Lim
Chin-Leong Lim
The main cause of loss in the PIN-Schottky limiter is the diodes’ parasitic capacitances. Techniques to counter the parasitic capacitances include using bare chip, air cavity packaging, diode stacking, mesa construction, isolating the Schottky diode from the signal path and connecting the diodes to a low impedance node. But the aforementioned techniques either sacrifice cost, manufacturability, size, performances or thermal ruggedness. To reduce loss in the PIN-Schottky limiter, we re-configured its parasitics into a low pass ladder network. This paper reports on the new configuration’s changed large signal and transient performances. We observed improved isolation at 0.9 and 2.4 GHz, …
Efficient Superposition Of Communication And Radar Waveforms (Raytheon), Anton Frolenkov, Vidie Pong, Sasha Sproch, Amy Whitcombe
Efficient Superposition Of Communication And Radar Waveforms (Raytheon), Anton Frolenkov, Vidie Pong, Sasha Sproch, Amy Whitcombe
Sasha A Sproch
The goal of the Raytheon-Olin SCOPE team was to identify pairs of communication and radar waveforms that could be superimposed through a single nonlinear amplifier while still fulfilling primary communications and radar functions. The team investigated candidate performance using hardware experimentation and industry-standard simulation. The results of this study begin to define the conditions for successful simultaneous communications and radar transmission through a single non-linear amplifier.
Balanced Uhf Lna Simplifies Cell Towers, Chin-Leong Lim
Balanced Uhf Lna Simplifies Cell Towers, Chin-Leong Lim
Chin-Leong Lim
Cellular basestations' low noise amplifiers (LNA) must have input impedances that are closely matched to the antennas. Unfortunately, the amplifier devices cannot be conjugate matched without sacrificing their noise performances. Current solutions such as the isolator and the balanced LNA can satisfactorily solve the matching problem but at the expense of increased cost, weight and size. On the other hand, the confined space atop cellular towers makes the current solutions unattractive. To shrink the balanced LNA for cellular infrastructure service, we pair a highly integrated dual-amplifier MMIC with miniature multilayer couplers. This MMIC also achieves the distinction of being the …
Brief Comparison Between 8051 And Avr, Ata Jahangir Moshayedi
Brief Comparison Between 8051 And Avr, Ata Jahangir Moshayedi
Ata Jahangir Moshayedi
Brief comparison between 8051 and AVR
Innovation, Proximity, And Knowledge Gatekeepers –Is Proximity A Necessity For Learning And Innovation?, Deogratias Harorimana Dr
Innovation, Proximity, And Knowledge Gatekeepers –Is Proximity A Necessity For Learning And Innovation?, Deogratias Harorimana Dr
Dr Deogratias Harorimana
Organisational desire for innovation and growth can be best achieved when they are in proximity. Geographical or technological proximity represent network structure in which a focal organisation is embedded, which has structural, cognitive and relational dimensions. Proximity influences innovation indirectly by its influence on agents’ ability to exchange and combine knowledge in four related ways: by giving access to exchange partners that provide opportunities for learning, increasing the anticipation of value, increasing the motivation to exchange, and by giving access to resources necessary for committing exchanges.
National Infrastructure Protection Priorities For Nuclear Electromagnetic Pulse (Emp) And Solar Storm Geomagnetic Disturbance Catastrophes, George H. Baker Iii
National Infrastructure Protection Priorities For Nuclear Electromagnetic Pulse (Emp) And Solar Storm Geomagnetic Disturbance Catastrophes, George H. Baker Iii
George H Baker
The Commission to Assess the Threat to the United States from Electromagnetic Pulse Attack has provided a compelling case for protecting civilian infrastructure against the effects of EMP and geomagnetic disturbances (GMD) caused by severe solar storms. Similar to protecting critical infrastructure against any hazard, it will be important to take a risk-based priority approach for these two electromagnetic threats, recognizing that it will be fiscally impracticable to protect everything. In this regard, EMP and GMD are particularly challenging in that they interfere with electrical and electronic data, control, transmission, and communication systems organic to nearly all critical infrastructures, simultaneously, …
Adaptive Control Of Apache Web Server, Erik Reed, Abe Ishihara, Ole J. Mengshoel
Adaptive Control Of Apache Web Server, Erik Reed, Abe Ishihara, Ole J. Mengshoel
Ole J Mengshoel
Wireless Transmission Network : A Imagine, Radhey Shyam Meena Engineer, Neeraj Kumar Garg Asst.Prof
Wireless Transmission Network : A Imagine, Radhey Shyam Meena Engineer, Neeraj Kumar Garg Asst.Prof
Radhey Shyam Meena
World cannot be imagined without electrical power. Generally the power is transmitted through transmission networks. This paper describes an original idea to eradicate the hazardous usage of electrical wires which involve lot of confusion in particularly organizing them. Imagine a future in which wireless power transfer is feasible: cell phones, household robots, mp3 players, laptop computers and other portable electronic devices capable of charging themselves without ever being plugged in freeing us from that final ubiquitous power wire. This paper includes the techniques of transmitting power without using wires with an efficiency of about 95% with non-radioactivemethods. In this paper …
The Development Of Payload Software For A Small Spacecraft, Kyle Goehner, Christoffer Korvald, Jeremy Straub, Ronald Marsh
The Development Of Payload Software For A Small Spacecraft, Kyle Goehner, Christoffer Korvald, Jeremy Straub, Ronald Marsh
Jeremy Straub
The OpenOrbiter project is a multi-department effort to design and build a small spacecraft which will demonstrate the feasibility of the Open Prototype for Educational NanoSats (OPEN) framework. This framework will reduce cost of small spacecraft creation by providing design plans for free. The focus of the payload software group is to design and implement an onboard task processing and image processing service. Currently the project is in the development phase and most large design decisions have been made. This poster presents the major design decisions that have been made for the payload software and how they will affect the …
Battery Energy Storage System In Solar Power Generation, Radhey Shyam Meena Er., Deepa Sharma
Battery Energy Storage System In Solar Power Generation, Radhey Shyam Meena Er., Deepa Sharma
Radhey Shyam Meena
Grid-connected solar PV dramatically changes the load profile of an electric utility customer. The expected widespread adoption of solar generation by customers on the distribution system poses significant challenges to system operators both in transient and steady state operation, from issues including voltage swings, sudden weather-induced changes in generation, and legacy protective devices designed with one-way power flow in mind
A Human Proximity Operations System Test Case Validation Approach, Justin Huber, Jeremy Straub
A Human Proximity Operations System Test Case Validation Approach, Justin Huber, Jeremy Straub
Jeremy Straub
A Human Proximity Operations System (HPOS) poses numerous risks in a real world environment. These risks range from mundane tasks such as avoiding walls and fixed obstacles to the critical need to keep people and processes safe in the context of the HPOS’s situation-specific decision making. Validating the performance of an HPOS, which must operate in a real-world environment, is an ill posed problem due to the complexity that is introduced by erratic (non-computer) actors. In order to prove the HPOS’s usefulness, test cases must be generated to simulate possible actions of these actors, so the HPOS can be shown …
Balanced Amplifier Aims For Low Noise, Chin-Leong Lim
Balanced Amplifier Aims For Low Noise, Chin-Leong Lim
Chin-Leong Lim
Cellular basestations' low noise amplifiers (LNA) must have input impedances that are closely matched to the antennas. Unfortunately, the amplifier devices cannot be conjugate matched without sacrificing their noise performances. Current solutions such as the isolator and the balanced LNA can satisfactorily solve the matching problem but at the expense of increased cost, weight and size. On the other hand, the confined space atop cellular towers makes the current solutions unattractive. To shrink the balanced LNA for cellular infrastructure service, we pair a highly integrated dual-amplifier MMIC with miniature multilayer couplers. This MMIC also has the distinction of being the …
Low Mismatch Uhf Lna For Cellular Infrastructure, Chin-Leong Lim
Low Mismatch Uhf Lna For Cellular Infrastructure, Chin-Leong Lim
Chin-Leong Lim
Cellular basestations' low noise amplifiers (LNA) must have input impedances that are closely matched to the antennas. Unfortunately, the amplifier devices cannot be conjugate matched without sacrificing their noise performances. Current solutions such as the isolator and the balanced LNA can satisfactorily solve the matching problem but at the expense of increased cost, weight and size. On the other hand, the confined space atop cellular towers makes the current solutions unattractive. To shrink the balanced LNA for cellular infrastructure service, we pair a highly integrated dual-amplifier MMIC with miniature multilayer couplers. This MMIC also achieves the distinction of being the …
A Study Of Mexican Free-Tailed Bat Chirp Syllables: Bayesian Functional Mixed Modeling Of Nonstationary Time Series Data With Time-Dependent Spectra, Josue G. Martinez, Kirsten M. Bohn, Raymond J. Carroll, Jeffrey S. Morris
A Study Of Mexican Free-Tailed Bat Chirp Syllables: Bayesian Functional Mixed Modeling Of Nonstationary Time Series Data With Time-Dependent Spectra, Josue G. Martinez, Kirsten M. Bohn, Raymond J. Carroll, Jeffrey S. Morris
Jeffrey S. Morris
We describe a new approach to analyze chirp syllables of free-tailed bats from two regions of Texas in which they are predominant: Austin and College Station. Our goal is to characterize any systematic regional differences in the mating chirps and assess whether individual bats have signature chirps. The data are analyzed by modeling spectrograms of the chirps as responses in a Bayesian functional mixed model. Given the variable chirp lengths, we compute the spectrograms on a relative time scale interpretable as the relative chirp position, using a variable window overlap based on chirp length. We use 2D wavelet transforms to …
Super-High-Frequency Two-Port Aln Contour-Mode Resonators For Rf Applications, Matteo Rinaldi, Chiara Zuniga, Chengjie Zuo, Gianluca Piazza
Super-High-Frequency Two-Port Aln Contour-Mode Resonators For Rf Applications, Matteo Rinaldi, Chiara Zuniga, Chengjie Zuo, Gianluca Piazza
Matteo Rinaldi
This paper reports on the design and experimental verification of a new class of thin-film (250 nm) superhigh- frequency laterally-vibrating piezoelectric microelectromechanical (MEMS) resonators suitable for the fabrication of narrow-band MEMS filters operating at frequencies above 3 GHz. The device dimensions have been opportunely scaled both in the lateral and vertical dimensions to excite a contourextensional mode of vibration in nanofeatures of an ultra-thin (250 nm) AlN film. In this first demonstration, 2-port resonators vibrating up to 4.5 GHz have been fabricated on the same die and attained electromechanical coupling, kt^2, in excess of 1.5%. These devices are employed to …
On Spectrum Probing In Cognitive Radio Networks: Does Randomization Matter, Chao Chen, Zesheng Chen, Todor Cooklev, Carlos Pomalaza-Ráez
On Spectrum Probing In Cognitive Radio Networks: Does Randomization Matter, Chao Chen, Zesheng Chen, Todor Cooklev, Carlos Pomalaza-Ráez
Todor Cooklev
In cognitive radio networks, dynamic spectrumaccess is achieved by allowing secondary users (SUs) to probethe spectrum and utilize available channels opportunistically.Spectrum probing mechanisms should be efficient and fast toavoid harmful interference with primary users (PUs). Periodicprobing has been commonly adopted as a default spectrumprobing mechanism. In this paper, we attempt to study differentspectrum probing mechanisms and evaluate a performance metriccalled the probing delay, i.e., how quickly a probing mechanismcan detect a channel change. We find that randomization in theprobing strategy does affect the probing delay. Specifically, in theindependent sensing scenario, periodic probing indeed achievesthe smallest probing delay. In the cooperative …
Uwb-Fsk: Performance Tradeoffs For High And Low Complexity Receivers, Todor Cooklev, Fernando Ramirez-Mireles, G. A. Paredes-Orozco
Uwb-Fsk: Performance Tradeoffs For High And Low Complexity Receivers, Todor Cooklev, Fernando Ramirez-Mireles, G. A. Paredes-Orozco
Todor Cooklev
In this work we explore flexible modulations toallow demodulation using receivers with different complexityand cost. More specifically, we study pulse-based ultrawideband (UWB) communications over channels with densemultipath effects using frequency shift keying (FSK) datamodulation. Our aim is to explore the performance tradeoffsbetween high and low complexity receivers. For this purposewe determine the performance of coherent, non-coherent andmismatched (e.g., non-coherent detection using templatesconsisting of a single path) demodulators. We take intoaccount the influence of the frequency response of the antennasystem and the effects of the frequency selectivity of themultipath channel. Given a specific channel condition, wederive expressions for the bit error …
Describing Radio Hardware And Software Using Owl For Over-The-Air Software Download, Todor Cooklev, Stanchev, David Clendenen
Describing Radio Hardware And Software Using Owl For Over-The-Air Software Download, Todor Cooklev, Stanchev, David Clendenen
Todor Cooklev
Recently, several researchers have discovered the need for radios to use description techniques. Previous research describes information such as the current frequency band, waveform, and so on. However, this information is presented at a level that is not sufficient to determine software/hardware compatibility for over-the-air software download. For example, a device should not attempt to download a wideband waveform if its radio front-end is only narrowband, or if its baseband hardware cannot provide the required MIPS for the new waveform. Over-the-air software download is one of the most interesting features of software-defined radios. The compatibility between software and hardware prior …
Greek Patent Protection System And The Impacts Of Information Technology Industry, Emmanouil Alexander Zografakis Ez
Greek Patent Protection System And The Impacts Of Information Technology Industry, Emmanouil Alexander Zografakis Ez
Emmanouil Alexander Zografakis EZ
Our era can be characterized as the era of knowledge proliferation and bountifulness. That has marked our era as the era following the pace of the Information Society Development. Information Society has also brought about a remarkable IT development pace over countries. Thereby, it is greatly important all that raw knowledge to become mind figments, ideas and even inventions and innovations. It is also essential to highlight that such a beneficial process will ensure the continuity of the IT development. The only way to achieve that goal is to find a way to secure all that aforementioned knowledge which is …
Battery Energy Storage System In Solar Power Generation, Radhey Shyam Meena Er.
Battery Energy Storage System In Solar Power Generation, Radhey Shyam Meena Er.
Radhey Shyam Meena
As solar photovoltaic power generation becomes more commonplace, the inherent intermittency of the solar resource poses one of the great challenges to those who would design and implement the next generation smart grid. Specifically, grid-tied solar power generation is a distributed resource whose output can change extremely rapidly, resulting in many issues for the distribution system operator with a large quantity of installed photovoltaic devices. Battery energy storage systems are increasingly being used to help integrate solar power into the grid. These systems are capable of absorbing and delivering both real and reactive power with sub-second response times. With these …
Robust Pci Planning For Long Term Evolution Technology, Ekta Gujral Miss
Robust Pci Planning For Long Term Evolution Technology, Ekta Gujral Miss
Ekta Gujral Miss
Long Term Evolution is one part of the 4G technology which targets the radio network Evolution. LTE is specified from Release 8 and 3GPP release 13 is available now days. The goal of LTE is to speed up the network and increase the capacity. The features of LTE technology is high data rates (DL > 100Mbps and UL > 50 Mbps). Spectral efficiency (1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15MHz, 20 MHz) make LTE robust. It is simple technology because of less signaling. The eNodeB is auto configurable. Every eNodeB have its own PCI (Physical Cell ID). According to 3GPP …
Connectivity Of Wireless Ad Hoc Networks: Impacts Of Antenna Models, Qiu Wang, Hong-Ning Dai, Qinglin Zhao
Connectivity Of Wireless Ad Hoc Networks: Impacts Of Antenna Models, Qiu Wang, Hong-Ning Dai, Qinglin Zhao
Hong-Ning Dai
This paper concerns the impact of various antenna models on the network connectivity of wireless ad hoc networks. Existing antenna models have their pros and cons in the accuracy reflecting realistic antennas and the computational complexity. We therefore propose a new directional antenna model called Approx-real to balance the accuracy against the complexity. We then run extensive simulations to compare the existing models and the Approx-real model in terms of the network connectivity. The study results show that the Approx-real model can better approximate the best accurate existing antenna models than other simplified antenna models, while introducing no high computational …
On Busy-Tone Based Mac Protocol For Wireless Networks With Directional Antennas, Hong-Ning Dai, Kam-Wing Ng, Min-You Wu
On Busy-Tone Based Mac Protocol For Wireless Networks With Directional Antennas, Hong-Ning Dai, Kam-Wing Ng, Min-You Wu
Hong-Ning Dai
The application of directional antennas in wireless ad hoc networks offers numerous benefits, such as the extended communication range, the increased spatial reuse, the improved capacity and the suppressed interference. However, directional antennas can cause new location-dependent carrier sensing problems, such as new hidden terminal and deafness problems, which can severely degrade the network performance. Recently, a few schemes have been proposed to address these problems. However, most of these existing methods can only partially solve the hidden terminal and deafness problems. Some of them even bring significant performance overhead. In this paper, we propose a novel MAC protocol, in …
Eavesdropping Security In Wireless Ad Hoc Networks With Directional Antennas, Qiu Wang, Hong-Ning Dai, Qinglin Zhao
Eavesdropping Security In Wireless Ad Hoc Networks With Directional Antennas, Qiu Wang, Hong-Ning Dai, Qinglin Zhao
Hong-Ning Dai
The eavesdropping security of wireless ad hoc networks has attracted considerable attention recently. However, most of current studies only consider OMN networks, where each node is mounted with a single omni-directional antenna, which radiates radio signals in all directions and consequently leads to the high eavesdropping possibility. Compared with an omnidirectional antenna, a directional antenna can concentrate the radio signals on some desired directions so that it can potentially reduce the eavesdropping possibility. This paper investigates the eavesdropping security of wireless ad hoc networks equipped with directional antennas. In particular, we study the eavesdropping possibility of OMN networks, SDA networks …
An Overview Of Using Directional Antennas In Wireless Networks, Hong-Ning Dai, Kam-Wing Ng, Min-You Wu
An Overview Of Using Directional Antennas In Wireless Networks, Hong-Ning Dai, Kam-Wing Ng, Min-You Wu
Hong-Ning Dai
Compared with omni-directional antennas, directional antennas have many merits, such as lower interference, better spatial reuse, longer transmission range and the improved network capacity. Directional antennas enable numerous emerging outdoor and indoor applications, which have been addressed in many recent studies. Despite the advances in wireless networks with directional antennas (DAWNs), there are many research challenges in all layers of DAWNs. This paper presents a detailed study on recent advances and open research issues on DAWNs. Firstly, we briefly introduce the classification of directional antennas, antenna radiation patterns, antenna modes as well as the challenges in the physical layer of …
Channel Allocation In Wireless Networks With Directional Antennas, Hong-Ning Dai, Kam-Wing Ng, Min-You Wu
Channel Allocation In Wireless Networks With Directional Antennas, Hong-Ning Dai, Kam-Wing Ng, Min-You Wu
Hong-Ning Dai
In this paper, we study the channel allocation in multi-channel wireless ad hoc networks with directional antennas. In particular, we investigate the problem: given a set of wireless nodes equipped with directional antennas, how many channels are needed to ensure collision-free communications? We derive the upper bounds on the number of channels, which heavily depend on the node density and the interference ratio (i.e., the ratio of the interference range to the transmission range). We construct several scenarios to examine the tightness of the derived bounds. We also take the side-lobes and back-lobes as well as the signal path loss …
On Eavesdropping Attacks In Wireless Sensor Networks With Directional Antennas, Hong-Ning Dai, Qiu Wang, Dong Li, Raymond Chi-Wing Wong
On Eavesdropping Attacks In Wireless Sensor Networks With Directional Antennas, Hong-Ning Dai, Qiu Wang, Dong Li, Raymond Chi-Wing Wong
Hong-Ning Dai
The eavesdropping attack is a serious security threat to a wireless sensor network (WSN) since the eavesdropping attack is a prerequisite for other attacks. Conventional WSNs consist of wireless nodes equipped with omnidirectional antennas, which broadcast radio signals in all directions and are consequently prone to the eavesdropping attacks. Different from omnidirectional antennas, directional antennas radiate radio signals on desired directions and potentially reduce the possibility of the eavesdropping attacks. In this paper, we propose a model to analyze the eavesdropping probability in both single-hop WSNs and multihop WSNs with omnidirectional antennas and directional antennas. We verify the correctness of …