Custom Integrated Circuits

Contains reports on ten research projects.Analog Devices, Inc.IBM CorporationNational Science Foundation/Defense Advanced Research Projects Agency Grant MIP 88-14612Analog Devices Career Development Assistant ProfessorshipU.S. Navy - Office of Naval Research Contract N0014-87-K-0825AT&TDigital Equipment CorporationNational Science Foundation Grant MIP 88-5876

Dynamically Adjusted and Peripheral Visualization of Reverse Optical Flow for VR Sickness Reduction

Sickness is a major obstacle in the wide adoption of virtual reality (VR). Providing low-resolution peripheral “countervection” visualization could mitigate VR sickness. Herein, we present an extension/improvement to this work, in which the reverse optical flow of the scene features is mixed in, and the extent of the periphery is dynamically adjusted simultaneously. We comparatively evaluated the effects of our extension versus the two notable sickness reduction techniques, (1) the original peripheral countervection flow using the simple stripe pattern (with a fixed field of view and peripheral extent) and (2) the dynamic field of view adjustment (with no added visualization). The experimental results indicated that the proposed extension exhibits competitive or better sickness reduction effects and less user-perceived content intrusion, distraction, and breaks in immersion/presence. Furthermore, we tested the comparative effect of visualizing the reverse optical flow only in the lower visual periphery, which further reduced the content intrusion and lowered the sense of immersion and presence. The test indicated that using just the low visual periphery could achieve a comparable level of sickness reduction with significantly less computational effort, making it suitable for mobile applications

PSR: Practical Synchronous Rendezvous in Low-duty-cycle Wireless Networks

Low-duty-cycle radio operations have been proposed for wireless networks facing severe energy constraints. Despite energy savings, duty-cycling the radio creates transient-available wireless links, making communication rendezvous a challenging task under the practical issue of clock drift. To overcome limitations of prior work, this paper presents PSR, a practical design for synchronous rendezvous in low-duty-cycle wireless networks. The key idea behind PSR is to extract timing information naturally embedded in the pattern of radio duty-cycling, so that normal traffic in the network can be utilized as a “free” input for drift detection, which helps reduce (or even eliminate) the overhead of traditional time-stamp exchange with dedicated packets or bits. To prevent an overuse of such free information, leading to energy waste, an energy-driven adaptive mechanism is developed for clock calibration to balance between energy efficiency and rendezvous accuracy. PSR is evaluated with both test-bed experiments and extensive simulations, by augmenting and comparing with four different MAC protocols. Results show that PSR is practical and effective under different levels of traffic load, and can be fused with those MAC protocols to improve their energy efficiency without major change of the original designs

Characterization, Antioxidant Activities, and Functional Properties of Mucilage Extracted from Corchorus olitorius L.

This study extracted the mucilage from Corchorus olitorius L. to observe its chemical and functional properties and suggest its possible applications in various fields. Corchorus olitorius L. mucilage was isolated by hot water extraction. FT-IR and HPAEC-PAD were used to describe the chemical composition, and the functional properties and antioxidant activities of the mucilage were also examined. The mucilage was mainly composed of uronic acid (34.24%, w/w). The solubility was 79.48 ± 1.08% at 65 °C, the swelling index was 29.01 ± 2.54% at 25 °C, and the water-holding capacity and oil-binding capacity were 28.66 ± 1.48 and 8.423 ± 0.23 g/g, respectively. The mucilage viscosity increased from 4.38 to 154.97 cP in a concentration-dependent manner. Increasing the concentration decreased the emulsion activity and increased the emulsion stability, most likely because of the corresponding increase in surface tension and viscosity. Results from antioxidant assays confirmed that the in-vitro radical scavenging activity of the mucilage increased with concentration. This study shows that C. olitorius L. can be utilized as a new hydrocolloid source, with potential applications in fields ranging from foods to cosmetics and pharmaceuticals

Single-User SFLC-OFDM System Realization Based on Channel Reciprocity Recovery

This paper demonstrates the implementation of a space–frequency line coded-orthogonal frequency-division multiplexing (SFLC-OFDM) system. The SFLC-OFDM system utilizes downlink channel state information at the transmitter, which can be obtained from uplink channel estimation under channel reciprocity assumption between uplink-and-downlink channels. However, in practical implementations, channel reciprocity is violated due to the imperfect synchronization and radio frequency chain mismatch between transceivers. To recover the channel reciprocity, frequency-domain signal processing methods are proposed. Furthermore, a low computational complexity single-instruction multiple-data method is implemented to meet the time constraints in real-time operating systems. The experimental results demonstrate that channel reciprocity can be effectively recovered in the implemented SFLC-OFDM system, resulting in practical communication performance regarding the symbol error rate

Vision Aided Dynamic Exploration of Unstructured Terrain with a Small-Scale Quadruped Robot

Abstract— Legged robots have been highlighted as promising mobile platforms for disaster response and rescue scenarios because of their rough terrain locomotion capability. In cluttered environments, small robots are desirable as they can maneuver through small gaps, narrow paths, or tunnels. However small robots have their own set of difficulties such as limited space for sensors, limited obstacle clearance, and scaleddown walking speed. In this paper, we extensively address these difficulties via effective sensor integration and exploitation of dynamic locomotion and jumping. We integrate two Intel RealSense sensors into the MIT Mini-Cheetah, a 0.3 m tall, 9 kg quadruped robot. Simple and effective filtering and evaluation algorithms are used for foothold adjustment and obstacle avoidance. We showcase the exploration of highly irregular terrain using dynamic trotting and jumping with the smallscale, fully sensorized Mini-Cheetah quadruped robot

A Therapeutic Nanovaccine that Generates Anti-Amyloid Antibodies and Amyloid-specific Regulatory T Cells for Alzheimer's Disease

Alzheimer's disease (AD), the most common cause of dementia, is a complex condition characterized by multiple pathophysiological mechanisms including amyloid-beta (A beta) plaque accumulation and neuroinflammation in the brain. The current immunotherapy approaches, such as anti-A beta monoclonal antibody (mAb) therapy, A beta vaccines, and adoptive regulatory T (Treg) cell transfer, target a single pathophysiological mechanism, which may lead to unsatisfactory therapeutic efficacy. Furthermore, A beta vaccines often induce T helper 1 (Th1) cell-mediated inflammatory responses. Here, a nanovaccine composed of lipid nanoparticles loaded with A beta peptides and rapamycin is developed, which targets multiple pathophysiological mechanisms, exhibits the combined effects of anti-A beta antibody therapy and adoptive A beta-specific Treg cell transfer, and can overcome the limitations of current immunotherapy approaches for AD. The Nanovaccine effectively delivers rapamycin and A beta peptides to dendritic cells, produces both anti-A beta antibodies and A beta-specific Treg cells, removes A beta plaques in the brain, alleviates neuroinflammation, prevents Th1 cell-mediated excessive immune responses, and inhibits cognitive impairment in mice. The nanovaccine shows higher efficacy in cognitive recovery than an A beta vaccine. Unlike anti-A beta mAb therapy and adoptive Treg cell transfer, both of which require complicated and costly manufacturing processes, the nanovaccine is easy-to-prepare and cost-effective. The nanovaccines can represent a novel treatment option for AD.N