Mobile video streaming has become an essential application in mobile wireless networks,making up most of the mobile data of today’s Internet traffic. Studies have shown that mobile video data is projected to make up about 78 percent of the global mobile data traffic, and that global mobile data traffic is...
Several frequency and amplitude estimation algorithms are presented for balanced and unbalanced three-phase power grid systems. All the estimators are dynamic in nature and are implemented in the complex domain by transforming the three-phase power signals using Clarke’s transform. Specifically, we first construct a non-linear dynamic model of the complex...
The need to detect trace amounts of target molecules is great, particularly when it comes to biosensing. With the early detection of a disease, the odds of the successful treatment of an individual increases significantly. To enhance the capability of biomolecular detection, we have created an optical biosensor capable of...
The electrical stability of amorphous indium-gallium-zinc oxide (a-IGZO) thinfilmtransistors (TFTs) is investigated for flat-panel display applications. Althoughproducts incorporating a-IGZO TFT backplanes are already commercially available,e.g., iMac with 5K retina display, technical challenges need to be addressed for nextgenerationapplications, e.g., active-matrix organic light-emitting diode displays.Device stability is one crucial issue. The...
The internet-of-things is a growing market segment which is based on an arrayof portable communication devices with high power efficiency. Advanced semiconductortechnology can easily improve their digital performance, but the samecannot be said for the analog blocks which are vital to their operation. Highperformance analog circuits continue to use conventional...
We demonstrated a low-cost and high-sensitivity DNA detection method using quantum dot-fullerene based molecular beacons (MBs) and magnetic nanoparticles. The MB tethered magnetic nanoparticles can be well dispersed in analytes for efficient DNA capture and concentrated by an external magnetic field for enhanced fluorescence signal detection. The detection requires only...
Energy consumption has become a great deal for cloud service providers due to financial as well as environmental concerns. Studies show that cloud servers operate, most of the time, at only between 10% and 50% of their maximal utilizations. These same studies also show that servers that are kept ON...
Cognitive radio technology emerges as a promising solution for overcoming shortage and inefficient use of spectrum resources. In cognitive radio networks, secondary users, which are users equipped with cognitive radios, can opportunistically access spectrum assigned to primary users, the spectrum license holders. Although it improves spectrum utilization efficiency, this opportunistic...
The rapid scaling of network bandwidth and data center throughput has motivated the wide adoption of high speed transceivers. Silicon photonics (Si-Photonic) is one of the most promising techniques to realize tightly integrated optical transceivers for next-generation high speed I O standards. This dissertation focuses on the design techniques of...
In this work, an alternating current (ac) magnetic susceptometer is designed and implemented to track the Brownian relaxation time of magnetic nanoparticles that are suspended in a liquid medium. The detection technique based on the Brownian relaxation time of magnetic nanoparticles has found its way in a variety of biosensing...
Back end of line (BEOL) metal-insulator-metal capacitors (MIMCAPs) have become a core passive component in modern integrated circuits. International Technology Roadmap for Semiconductors (ITRS) projections for scaling of analog/mixed-signal MIMCAP applications require simultaneously increasing capacitance density while maintaining low leakage current density and low voltage nonlinearity (characterized by the quadratic...
Triangulateration uses geometric distance to estimate the location of user by employing techniques like received signal strength (RSS), time-of-arrival (TOA), time-difference-of-arrival (TDOA) and image processing.
Radio frequency (RF) signal positioning using TOA or TDOA techniques generally requires timing synchronization of the anchors and/or the anchors and targets. If the desired...
We explored an optofluidic sensing mechanism from inkjet-printed droplets on diatom biosilica using surface-enhanced Raman scattering (SERS). Our study revealed a new biosensing strategy that combines the microscopic fluidic flow induced by the droplet evaporation and the photonic crystal effects of diatom frustules, which can provide an ultra-sensitive, cost-effective biosensing...
Coverage algorithms for deployment of WiFO - a hybrid femtocell architecture based on WiFi and Free Space Optical (FSO) technologies are studied to significantly increase wireless throughput of existing WiFi networks. In contrast with existing WiFi networks, WiFO incorporates small cell size, line of sight transmissions, and the Gaussian attenuation...
Massive Multiple-User Miltiple-Input Multiple-Output (MU-MIMO) wireless communication systems incorporate promising advanced strong technologies for upcoming 5G communications. To obtain some of the high spectrum and energy e ciencies bonuses brought by MU-MIMO systems, the ability to obtain Channel State information, especially on the receiver side (CSI), is important. To minimize...
Hyperthermia is a cancer therapy that relies on the local heating of a cancerous tumor to kill cancer cells and disrupt the future growth of the tumor. While hyperthermia is capable of killing tumors separately, physicians often combine it with other treatment methods, typically radiation therapy, for its synergistic effects...
With explosive growth of Internet access from smart phones and tablets, increasing bandwidth for WIFI system is badly needed. Depending on two years’ research, we produced a novel communication system called WIFO system, which integrates both RF (Radio Frequency) and FSO (Free Space Optical) techniques. WIFO system can significantly increase...
In college transmission lines courses, students are expected to understand how different circuit configurations affect the signals on a transmission line. Having a way to visualize these signals can greatly improve their learning experience. This thesis details the development of an open source, interactive learning tool used to illustrate fundamental...
The majority of power system cascading models assume that system operators will
react perfectly and timely to an electrical event. However, as evidenced by several
blackouts in the last decades, the inadequate system operators’ situation awareness
and response can contribute significantly to the severity of an electrical disturbance.
Under these...
Wireless power transfer (WPT) is a way to transfer power from one device to another without any wire or cable connections. Although the technology has been around for more than 100 years, it is gaining popularity in recent years due to the ever-increasing demand for faster and more frequent charging...
Due to a lack of grain boundaries, an amorphous metal thin film (AMTF) possesses advantageous mechanical properties and enhanced chemical stability that is potentially useful for thermal inkjet (TIJ) printing applications. The use of an AMTF as a TIJ resistor or cavitation plate could lead to a thinner TIJ cavitation...
As the CMOS process scales down to submicron, digital circuit performance improves, while reduced supply voltage and lower transistor intrinsic gain make it difficult to implement analog circuits in a power efficient manner. Therefore, it has become advantageous to shift more analog signal processing functions conventionally realized in voltage (analog)...
Recent sensor System-on-Chips (SoC) have enabled significant advances in energy-efficiency by incorporating various micro-powered building blocks. Unfortunately, most of these sensor systems do not address the high power cost associated with data storage and transmission, which in some cases vastly exceeds the power consumed by the rest of the SoC....
Spintronics is an emerging field of research wherein the electron spin instead of, or along with, the conventional electron charge may be utilized in developing next generation logic devices. One of the most promising aspects of spintronics is that information transfer may be achieved by spin waves in logic devices,...
Recently, there has been peaked interest in developing high energy producing and optimized power take-off topologies for Wave Energy Converters (WEC). As large as the potential of the oceans may seem, harnessing that energy and effectively converting it to electricity in significant amounts is a challenge. Currently, there are no...
The current state of research on gossip techniques for wireless broadcasting is very limited because past research efforts have mostly focused on using gossip techniques for multicast communication. On the other hand, those research efforts that have focused on using gossip techniques for wireless broadcast communications ignore energy efficiency and...
It has been estimated that data traffic from the different mobile devices that range from smartphones to machine-to-machine (M2M) devices will exceed 15.9 exabyte per month by the year 2018. With this immense data growth, the current wireless communication systems suffer from the scarcity of the radio spectrum and eventually...
In bioacoustics, automatic animal voice detection and recognition from audio recordings is an emerging topic for animal preservation. Our research focuses on bird bioacoustics, where the goal is to segment bird syllables from the recording and predict the bird species for the syllables. Traditional methods for this task addresses the...
This dissertation presents a phase domain in-loop-bandwidth spread-spectrum clock generation technique. In this proposed technique, a charge-based discrete-time loop filter is proposed to enable the phase domain in-loop-bandwidth spread-spectrum modulation without a delta-sigma modulator or time-to-digital converter. The in-loop-bandwidth modulation technique maximizes the loop bandwidth to improve phase noise suppression...
This dissertation focuses on the development of ultra-compact optical devices for free-space modulation. We propose a surface-normal modulator using metallic photonic crystals for free-space optical interconnects. The active control of light intensity is achieved by engineering the Fano resonances in metallic photonic crystals. Both thermo-optic modulation and electro-optic modulation of...
This project is a custom output stage for a two-channel signal source design project at Oregon State. Starting in January, I began leading a team tasked with the development of an arbitrary waveform generator via the CreateIT Collaboratory at OSU. Undergraduate students interview into the CreateIT Collaboratory and are assigned...
Incremental ADCs (IADCs) have found wide applications in sensor interface circuitry since, compared to ∆Σ ADCs, they provide low-latency high-accuracy conversion and easy multiplexing among multiple channels. On the other hand, continuous-time ∆Σ ADCs (CTDSM) have been receiving more and more attention as a power-efficient solution in targeting medium to...
In wireless communication, channel state information (CSI) is essential for data detection. Fast fading coefficients estimation is important in order to acquire accurate CSI. Kalman filters (KF) are widely used for real time parameter estimation and can be used to estimate the fast fading coefficients of a mobile communication channel....
Deep learning has greatly improved visual recognition in recent years. However, recent research has shown that there exist many adversarial examples that can negatively impact the performance of such an architecture. Different from previous perspectives that focus on improving the classifiers to detect the adversarial examples, this work focuses on...
Massive MIMO is a promising technique for future 5G communications due to its high spectrum and energy efficiency. To realize its potential performance gain, accurate channel state information at transmitter side (CSIT) is essential. Frequency division duplex (FDD) is widely employed by the most cellular systems today. However, it requires...
Transparent conductive oxides (TCOs), primarily indium doped tin oxide, have been widely used in numerous fields since decades ago, such as solar cells, displays, OLEDs and ‘smart windows’ etc. Owing to the scarcity of indium, there is a great demand for new alternative materials. Metal/insulator/metal (MIM) diodes are a critical...
Magnetic thin films have potential to improve devices such as on-chip inductors, and enable new technologies such as magnetic random access memory (MRAM).
The use of magnetic cores in on-chip inductors is typically limited to applications well under 1 GHz. At higher frequencies, the performance of the magnetic core is...
As scaling of silicon (Si) based devices approaches fundamental limits, thin film metal-insulator-metal (MIM) tunnel diodes are attracting interest due to their potential for high speed operation. Because operation of these devices is based on tunneling, electrode / interfacial roughness is critical. Recently, it was shown that combining ultra-smooth bottom...
The National Conference of State Legislatures NCSL declares that 29 states have
been active in adopting and increasing renewable portfolio standards. Present
renewable portfolio standards require utilities to increase integration of renewable
energy sources such as photovoltaic (PV). The increased penetration of PV systems
is expected to destabilize the power...
Disaster response robots need to be simultaneously able to survive extreme environment and complete the mission efficiently and robustly. One of the determinants is the performance of the actuators in each joint, which drive the robot to the desired motion accurately. In robotics society, people usually build their robots directly...
Inkjet printing offers a cost effective, highly customizable method for rapid manufacturing of functional devices with minimal material waste. Although this method has been used for a variety of composites, little work has been done in the area of 3D printing magnetic composites. Presented here is a process for inkjet...
As the price of broadband access service becomes more affordable, the number of homes with WiFi and public WiFi hotspots in the US are projected to increase significantly in the next few years. However, limited capacity of existing WiFi networks fail to provide adequate bandwidth for densely populated areas. Therefore,...
This work presents the design and implementation of a low power phased-array receiver frontend at 28 GHz in 65 nm CMOS. The frontend incorporates a low- power low-noise amplifier(LNA) and a passive reflection-type phase shifter (RTPS) capable of providing 360° phase shift with 5-bit phase resolution and low loss variation....
Modern variable speed machine drive (VSMD) systems are used for a variety of purposes including generation, propulsion, pumps and compressors. They employ high switching frequency power electronics to drive the electric machine. The machine is subject to large voltage overshoot if long power cables, are used, called Reflected Wave Phenomena...
Recent opportunities for new hydropower generation in the United States have often been in non-powered dams and run-of-river type flows occurring in low-impact natural areas and unregulated conduits. At the same time, a changing water resource paradigm is challenging some existing generation in drought stricken areas where supply reservoirs behind...
Hybrid automatic repeat request (HARQ) schemes combine packet retransmission with forward error correction to ensure a reliable communications. In multiple-input multiple output (MIMO) systems, interference cancellation (IC) detection is widely used where the detection and cancellation steps of the simultaneously transmitted data streams occur. In principle, the signal stream estimated...
Wireless localization of objects is useful for several applications that require the knowledge
of position of objects or people. Additionally, power extraction from wireless
signals eliminates the need for wires or any physical connections for charging. This
project is based on system-level testing of an integrated circuit (IC) that combines...
Diabetes is a pandemic that affects nearly 29.1 million Americans and the fourth leading cause of mortality in the US. Type 1 diabetes is a chronic condition which occurs due to little to no production of insulin by the pancreas. This form of diabetes requires constant monitoring of blood glucose...
Threshold-based time of arrival (TOA) estimation is a technique for high-precision indoor localization. Existing threshold selection methods, such as xed thresh- old and normalized threshold methods, do not consider the signal-to-noise radio (SNR) value at the receiver. This is not desired for high-precision positioning. A proper threshold value depends on...
Optical wireless communication (OWC) is an alternative to radio frequency (RF)communication with a signi cantly larger and unregulated spectrum. In OWC systems, optical orthogonal frequency division multiplexing (O-OFDM) with intensity modulation and direct detection (IM/DD) is commonly used. There are two common signal structures in most OWC systems based on...