Development and Evaluation of a Multistatic Ultrawideband Random Noise Radar

This research studies the AFIT noise network (NoNET) radar node design and the feasibility in processing the bistatic channel information of a cluster of widely distributed noise radar nodes. A system characterization is used to predict theoretical localization performance metrics. Design and integration of a distributed and central signal and data processing architecture enables the Matlab®-driven signal data acquisition, digital processing and multi-sensor image fusion. Experimental evaluation of the monostatic localization performance reveals its range measurement error standard deviation is 4.8 cm with a range resolution of 87.2(±5.9) cm. The 16-channel multistatic solution results in a 2-dimensional localization error of 7.7(±3.1) cm and a comparative analysis is performed against the netted monostatic solution. Results show that active sensing with a low probability of intercept (LPI) multistatic radar, like the NoNET, is capable of producing sub-meter accuracy and near meter-resolution imagery

MATTERS OF GRAVITY, a newsletter for the gravity community, Number 3

Table of contents Editorial Correspondents Gravity News: Open Letter to gravitational physicists, Beverly Berger A Missouri relativist in King Gustav's Court, Clifford Will Gary Horowitz wins the Xanthopoulos award, Abhay Ashtekar Research briefs: Gamma-ray bursts and their possible cosmological implications, Peter Meszaros Current activity and results in laboratory gravity, Riley Newman Update on representations of quantum gravity, Donald Marolf Ligo project report: December 1993, Rochus E. Vogt Dark matter or new gravity?, Richard Hammond Conference reports: Gravitational waves from coalescing compact binaries, Curt Cutler Mach's principle: from Newton's bucket to quantum gravity, Dieter Brill Cornelius Lanczos international centenary conference, David Brown Third Midwest relativity conference, David GarfinkleComment: Number 3, Plain Tex, 37 page

Circuit Techniques for Low-Power and Secure Internet-of-Things Systems

The coming of Internet of Things (IoT) is expected to connect the physical world to the cyber world through ubiquitous sensors, actuators and computers. The nature of these applications demand long battery life and strong data security. To connect billions of things in the world, the hardware platform for IoT systems must be optimized towards low power consumption, high energy efficiency and low cost. With these constraints, the security of IoT systems become a even more difficult problem compared to that of computer systems. A new holistic system design considering both hardware and software implementations is demanded to face these new challenges. In this work, highly robust and low-cost true random number generators (TRNGs) and physically unclonable functions (PUFs) are designed and implemented as security primitives for secret key management in IoT systems. They provide three critical functions for crypto systems including runtime secret key generation, secure key storage and lightweight device authentication. To achieve robustness and simplicity, the concept of frequency collapse in multi-mode oscillator is proposed, which can effectively amplify the desired random variable in CMOS devices (i.e. process variation or noise) and provide a runtime monitor of the output quality. A TRNG with self-tuning loop to achieve robust operation across -40 to 120 degree Celsius and 0.6 to 1V variations, a TRNG that can be fully synthesized with only standard cells and commercial placement and routing tools, and a PUF with runtime filtering to achieve robust authentication, are designed based upon this concept and verified in several CMOS technology nodes. In addition, a 2-transistor sub-threshold amplifier based "weak" PUF is also presented for chip identification and key storage. This PUF achieves state-of-the-art 1.65% native unstable bit, 1.5fJ per bit energy efficiency, and 3.16% flipping bits across -40 to 120 degree Celsius range at the same time, while occupying only 553 feature size square area in 180nm CMOS. Secondly, the potential security threats of hardware Trojan is investigated and a new Trojan attack using analog behavior of digital processors is proposed as the first stealthy and controllable fabrication-time hardware attack. Hardware Trojan is an emerging concern about globalization of semiconductor supply chain, which can result in catastrophic attacks that are extremely difficult to find and protect against. Hardware Trojans proposed in previous works are based on either design-time code injection to hardware description language or fabrication-time modification of processing steps. There have been defenses developed for both types of attacks. A third type of attack that combines the benefits of logical stealthy and controllability in design-time attacks and physical "invisibility" is proposed in this work that crosses the analog and digital domains. The attack eludes activation by a diverse set of benchmarks and evades known defenses. Lastly, in addition to security-related circuits, physical sensors are also studied as fundamental building blocks of IoT systems in this work. Temperature sensing is one of the most desired functions for a wide range of IoT applications. A sub-threshold oscillator based digital temperature sensor utilizing the exponential temperature dependence of sub-threshold current is proposed and implemented. In 180nm CMOS, it achieves 0.22/0.19K inaccuracy and 73mK noise-limited resolution with only 8865 square micrometer additional area and 75nW extra power consumption to an existing IoT system.PHDElectrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/138779/1/kaiyuan_1.pd

The development and implementation of a single-line intelligent digital telephone answering unit on a personal computer

ThesisCommercial telephone answering machines are limited to some extent by one or more of the following factors: • limited facilities • difficult to upgrade • nonstandard telephone interfacing • expensive • lack of user-friendliness • lack of dialogue and intelligence The purpose of this study is to design an intelligent digital telephone system which will overcome as many of the above-mentioned problems as possible. The following features are proposed and will be discussed: The use of a commonly available, but powerful, personal computer processor and memory instead of the elementary and rigid processor and magnetic tape storage units of the commercial telephone answering machine . This allows the quick storage and retrieval of digitized messages, each with its individual name, time and date stamp. Using the personal computer's hardware and not duplicating the processor and memory units allows a more cost-effective system upgrade. Upgrades mainly consist of software changes and minor hardware changes. This means that an upgrade does not implicate a total hardware redesign. Standards as prescribed by the local switching network standards and the Department of Post and Telecommunications, apply to this design and are applicable for licensing of the product. It is evident that the cost of this project and design is kept minimal by not duplicating expensive components like the microprocessor and the memory units, although these are used in the design. In this respect upgrades are software orientated to further limit the costs. The personal computer is equipped with a display which allows the user to make easy selections in order to execute the required instructions or to obtain information by using the help functions. This real-time help function eliminates the need for a user manual. Dialogue between user and personal computer over the telephone network offers a simple method of delivering information without the need for any extra equipment such as modems, keyboards or display units. The software used on the personal computer is designed in such a way that the system is intelligent and capable of decision making. Communication from the public telephone network is possible by using the telephone keypad and Dual Tone Multifrequency (DTMF) signalling

Polarization techniques for mitigation of low grazing angle sea clutter

Maritime surveillance radars are critical in commerce, transportation, navigation, and defense. However, the sea environment is perhaps the most challenging of natural radar backdrops because maritime radars must contend with electromagnetic backscatter from the sea surface, or sea clutter. Sea clutter poses unique challenges in very low grazing angle geometries, where typical statistical assumptions regarding sea clutter backscatter do not hold. As a result, traditional constant false alarm rate (CFAR) detection schemes may yield a large number of false alarms while objects of interest may be challenging to detect. Solutions posed in the literature to date have been either computationally impractical or lacked robustness. This dissertation explores whether fully polarimetric radar offers a means of enhancing detection performance in low grazing angle sea clutter. To this end, MIT Lincoln Laboratory funded an experimental data collection using a fully polarimetric X-band radar assembled largely from commercial off-the-shelf components. The Point de Chene Dataset, collected on the Atlantic coast of Massachusetts’ Cape Ann in October 2015, comprises multiple sea states, bandwidths, and various objects of opportunity. The dataset also comprises three different polarimetric transmit schemes. In addition to discussing the radar, the dataset, and associated post-processing, this dissertation presents a derivation showing that an established multiple input, multiple output radar technique provides a novel means of simultaneous polarimetric scattering matrix measurement. A novel scheme for polarimetric radar calibration using a single active calibration target is also presented. Subsequent research leveraged this dataset to develop Polarimetric Co-location Layering (PCL), a practical algorithm for mitigation of low grazing angle sea clutter, which is the most significant contribution of this dissertation. PCL routinely achieves a significant reduction in the standard CFAR false alarm rate while maintaining detections on objects of interest. Moreover, PCL is elegant: It exploits fundamental characteristics of both sea clutter and object returns to determine which CFAR detections are due to sea clutter. We demonstrate that PCL is robust across a range of bandwidths, pulse repetition frequencies, and object types. Finally, we show that PCL integrates in parallel into the standard radar signal processing chain without incurring a computational time penalty