Ultra-Low-Power Embedded SRAM Design for Battery- Operated and Energy-Harvested IoT Applications

Internet of Things (IoT) devices such as wearable health monitors, augmented reality goggles, home automation, smart appliances, etc. are a trending topic of research. Various IoT products are thriving in the current electronics market. The IoT application needs such as portability, form factor, weight, etc. dictate the features of such devices. Small, portable, and lightweight IoT devices limit the usage of the primary energy source to a smaller rechargeable or non-rechargeable battery. As battery life and replacement time are critical issues in battery-operated or partially energy-harvested IoT devices, ultra-low-power (ULP) system on chips (SoC) are becoming a widespread solution of chip makers’ choice. Such ULP SoC requires both logic and the embedded static random access memory (SRAM) in the processor to operate at very low supply voltages. With technology scaling for bulk and FinFET devices, logic has demonstrated to operate at low minimum operating voltages (VMIN). However, due to process and temperature variation, SRAMs have higher VMIN in scaled processes that become a huge problem in designing ULP SoC cores. This chapter discusses the latest published circuits and architecture techniques to minimize the SRAM VMIN for scaled bulk and FinFET technologies and improve battery life for ULP IoT applications

Violating privacy through walls by passive monitoring of radio windows

pre-printWe investigate the ability of an attacker to passively use an otherwise secure wireless network to detect moving people through walls. We call this attack on privacy of people a "monitoring radio windows" (MRW) attack. We design and implement the MRW attack methodology to reliably detect when a person crosses the link lines between the legitimate transmitters and the attack receivers, by using physical layer measurements. We also develop a method to estimate the direction of movement of a person from the sequence of link lines crossed during a short time interval. Additionally, we describe how an attacker may estimate any artificial changes in transmit power (used as a countermeasure), compensate for these power changes using measurements from sufficient number of links, and still detect line crossings. We implement our methodology on WiFi and ZigBee nodes and experimentally evaluate the MRW attack by passively monitoring human movements through external walls in two real-world settings. We find that achieve close to 100% accuracy in detecting line crossings and determining direction of motion, even through reinforced concrete walls

Detecting receiver attacks in VRTI-based device free localization

pre-printVariance-based Radio Tomographic Imaging (VRTI) is an emerging technology that locates moving objects in areas surrounded by simple and inexpensive wireless sensor nodes. VRTI uses human motion induced variation in RSS and spatial correlation between link variations to locate and track people. An artificially induced power variations in the deployed network by an adversary can introduce unprecedented errors in localization process of VRTI and, given the critical applications of VRTI, can potentially lead to serious consequences including loss of human lives. In this paper, we tackle the problem of detecting malicious receivers that report false RSS values to induce artificial power variations in a VRTI system. We use the term "Receiver Attack" to refer to such malicious power changes. We use a combination of statistical hypothesis testing and heuristics to develop real-time methods to detect receiver attack in a VRTI system. Our results show that we can detect receiver attacks of reasonable intensity and identify the source(s) of malicious activity with very high accuracy

Adiabatic charge pumping through a dot at the junction of N quantum wires

We study adiabatic charge pumping through a quantum dot placed at the junction of $N$ quantum wires. We explicitly map out the pattern of pumped charge as a function of the time-varying tunneling parameters coupling the wires to the dot and the phase between any two time varying parameters controlling the shape of the dot. We find that with $N-2$ time-independent well-coupled leads, the maximum pumped charge in the remaining two leads is strongly suppressed with increasing $N$, leading to the possibility of tuning of the pumped charge, by modulating the coupling of the $N-2$ leads.Comment: 5 pages, 6 figures, version to be published in PR

Recent Advances on Design and Synthesis of Chiral Imidazolium Ionic Liquids and their Applications in Green Asymmetric Synthesis

Over the past decade, catalysis by ionic liquids (ILs) has experienced a tremendous growth in the context of “Green Chemistryâ€, and there are numerous examples of a variety of catalytic reactions that have been successfully carried out in such neoteric media.The great enthusiasm for catalysis in ILs is not only driven by the curiosity of chemists, but also due to the growing awareness of developing greener reactions or process media in catalytic science and greener catalytic technologies due their advantages of unique physical and chemical properties as compared to traditional volatile organic solvents.Recently, development of chiral ionic liquids and their applications in asymmetric synthesis have attracted much attention as these reactions have widespread applications in the synthesis of chiral drugs and pharmaceutical industries. Asymmetric induction is mainly achieved by the use of chiral substrates or reagents, chiral catalysts or enzymes. Owing to the vast number of structurally different room temperature ILS that have been synthesized, this review focuses on imidazolium ionic liquids that possess chirality either in the imidazolium moiety or in the anion moiety. The aim of this review is to highlight the recent breakthrough of Chiral ILs in chirality transfer or chiral recognition when used as solvent or co-solvent: the case of task specific ionic liquids is beyond the scope of this review. In the first part, the synthesis of of CILs has been presented and the second part of the review has been devoted on the applications of such CILs in green asymmetric synthesis as well as various pharmaceutical industries

Possible detection of interstellar glycine in the hot molecular core G10.47+0.03

Amino acids are the essential keys in chemistry that contribute to the study of the formation of life. The complex organic molecule glycine (NH$_{2}$CH$_{2}$COOH) is the simplest amino acid that has been investigated in the interstellar medium for a long period to search for a potential connection between the Universe and the origin of life. In the last forty years, several attempts have failed to detect the interstellar glycine in the hot molecular cores and star-forming regions. We report the possible detection of the rotational emission lines of interstellar glycine with conformer I and II in the hot molecular core G10.47+0.03 between the frequency range of $\nu$ = 158.6$-$160.4 GHz with Atacama Large Millimeter/Submillimeter Array (ALMA) observation. Under the Local Thermodynamic Equilibrium (LTE) condition, we apply the rotational diagram method to estimate the column density ($N$) and rotational temperature ($T_{rot}$) of the detected amino acid glycine. Using rotational diagram, we find the column density of glycine $N$(NH$_{2}$CH$_{2}$COOH) = 2.8$\times$10$^{18}$ cm$^{-2}$ with rotational temperature $T_{rot}$ = 115.9 K. We also apply the Levenberg$-$Marquardt algorithm to extract the line parameters of detected emission lines of glycine.Comment: Comments are welcom

Higher-order topological corner and bond-localized modes in magnonic insulators

We theoretically investigate a novel two-dimensional decorated honeycomb lattice framework to realize a second-order topological magnon insulator (SOTMI) phase featuring distinct corner-localized modes. Our study emphasizes the pivotal role of spin-magnon mapping in characterizing bosonic topological properties, which exhibit differences from their fermionic counterparts. We employ a symmetry indicator topological invariant to identify and characterize this SOTMI phase, particularly for systems respecting time-reversal and ${\sf{C}}_6$ rotational symmetry. Using a spin model defined on a honeycomb lattice geometry, we demonstrate that introducing "kekule" type distortions yields a topological phase. In contrast, anti-kekule" distortions result in a non-topological magnonic phase. The presence of kekule distortions manifests in two distinct topologically protected bosonic corner modes - an "intrinsic" and a "pseudo", based on the specific edge terminations. On the other hand, anti-kekule distortions give rise to bond-localized boundary modes, which are non-topological and reliant on particular edge termination. We further investigate the effects of random out-of-plane exchange anisotropy disorder on the robustness of these bosonic corner modes. The distinction between SOTMIs and their fermionic counterparts arises due to the system-specific magnonic onsite energies, a crucial feature often overlooked in prior literature. Our study unveils exciting prospects for engineering higher-order topological phases in magnon systems and enhances our understanding of their unique behavior within decorated honeycomb lattices.Comment: 4.5 Pages, 4 PDF Figures (main text) + 3 Pages, 3 PDF Figures (Supplementary Material), Comments are welcom