Area and Energy Optimizations in ASIC Implementations of AES and PRESENT Block Ciphers

When small, modern-day devices surface with neoteric features and promise benefits like streamlined business processes, cashierless stores, and autonomous driving, they are all too often accompanied by security risks due to a weak or absent security component. In particular, the lack of data privacy protection is a common concern that can be remedied by implementing encryption. This ensures that data remains undisclosed to unauthorized parties. While having a cryptographic module is often a goal, it is sometimes forfeited because a device's resources do not allow for the conventional cryptographic solutions. Thus, smaller, lower-energy security modules are in demand. Implementing a cipher in hardware as an application-specific integrated circuit (ASIC) will usually achieve better efficiency than alternatives like FPGAs or software, and can help towards goals such as extended battery life and smaller area footprint. The Advanced Encryption Standard (AES) is a block cipher established by the National Institute of Standards and Technology (NIST) in 2001. It has since become the most widely adopted block cipher and is applied in a variety of applications ranging from smartphones to passive RFID tags to high performance microprocessors. PRESENT, published in 2007, is a smaller lightweight block cipher designed for low-power applications. In this study, low-area and low-energy optimizations in ASICs are addressed for AES and PRESENT. In the low-area work, three existing AES encryption cores are implemented, analyzed, and benchmarked using a common fabrication technology (STM 65 nm). The analysis includes an examination of various implementations of internal AES operations and their suitability for different architectural choices. Using our taxonomy of design choices, we designed Quark-AES, a novel 8-bit AES architecture. At 1960 GE, it features a 13% improvement in area and 9% improvement in throughput/area² over the prior smallest design. To illustrate the extent of the variations due to the use of different ASIC libraries, Quark-AES and the three analyzed designs are also synthesized using three additional technologies. Even for the same transistor size, different ASIC libraries produce significantly different area results. To accommodate a variety of applications that seek different levels of tradeoffs in area and throughput, we extend all four designs to 16-bit and 32-bit datawidths. In the low-energy work, round unrolling and glitch filtering are applied together to achieve energy savings. Round unrolling, which applies multiple block cipher rounds in a combinational path, reduces the energy due to registers but increases the glitching energy. Glitch filtering complements round unrolling by reducing the amount of glitches and their associated energy consumption. For unrolled designs of PRESENT and AES, two glitch filtering schemes are assessed. One method uses AND-gates in between combinational rounds while the other used latches. Both methods work by allowing the propagation of signals only after they have stabilized. The experiments assess how energy consumption changes with respect to the degree of unrolling, the glitch filtering scheme, the degree of pipelining, the spacing between glitch filters, and the location of glitch filters when only a limited number of them can be applied due to area constraints. While in PRESENT, the optimal configuration depends on all the variables, in a larger cipher such as AES, the latch-based method consistently offers the most energy savings

Towards Precision Supermassive Black Hole Masses using Megamaser Disks

Megamaser disks provide the most precise and accurate extragalactic supermassive black hole masses. Here we describe a search for megamasers in nearby galaxies using the Green Bank Telescope (GBT). We focus on galaxies where we believe that we can resolve the gravitational sphere of influence of the black hole and derive a stellar or gas dynamical measurement with optical or NIR observations. Since there are only a handful of super massive black holes (SMBH) that have direct black hole mass measurements from more than one method, even a single galaxy with a megamaser disk and a stellar dynamical black hole mass would provide necessary checks on the stellar dynamical methods. We targeted 87 objects from the Hobby-Eberly Telescope Massive Galaxy Survey, and detected no new maser disks. Most of the targeted objects are elliptical galaxies with typical stellar velocity dispersions of 250 km/s and distances within 130 Mpc. We discuss the implications of our non-detections, whether they imply a threshold X-ray luminosity required for masing, or possibly reflect the difficulty of maintaining a masing disk around much more massive (>10^8 Msun) black holes at low Eddington ratio. Given the power of maser disks at probing black hole accretion and demographics, we suggest that future maser searches should endeavour to remove remaining sample biases, in order to sort out the importance of these covariant effects.Comment: 9 pages, 5 figures, Apj, updated to match the accepted versio

Refining the M_BH-V_c scaling relation with HI rotation curves of water megamaser galaxies

Black hole - galaxy scaling relations provide information about the coevolution of supermassive black holes and their host galaxies. We compare the black hole mass - circular velocity (MBH - Vc) relation with the black hole mass - bulge stellar velocity dispersion (MBH - sigma) relation, to see whether the scaling relations can passively emerge from a large number of mergers, or require a physical mechanism, such as feedback from an active nucleus. We present VLA H I observations of five galaxies, including three water megamaser galaxies, to measure the circular velocity. Using twenty-two galaxies with dynamical MBH measurements and Vc measurements extending to large radius, our best-fit MBH - Vc relation, log MBH = alpha + beta log(Vc /200 km s^-1), yields alpha = 7.43+/-0.13, beta = 3.68+1.23/-1.20, and intrinsic scatter epsilon_int = 0.51+0.11/-0.09. The intrinsic scatter may well be higher than 0.51, as we take great care to ascribe conservatively large observational errors. We find comparable scatter in the MBH - sigma relations, epsilon_int = 0.48+0.10/-0.08, while pure merging scenarios would likely result in a tighter scaling with the dark halo (as traced by Vc) than baryonic (sigma) properties. Instead, feedback from the active nucleus may act on bulge scales to tighten the MBH - sigma relation with respect to the MBH - Vc relation, as observed.Comment: 27 pages, 15 figures, ApJ accepte

Many Uninsured Children Qualify for Medi-Cal or Healthy Families

Examines the public health insurance eligibility of children in California who did not have health insurance coverage for some or all of the year in 2002, to highlight the geographic variations in children's uninsured eligibility rates

Robustness of Utilizing Feedback in Embodied Visual Navigation

This paper presents a framework for training an agent to actively request help in object-goal navigation tasks, with feedback indicating the location of the target object in its field of view. To make the agent more robust in scenarios where a teacher may not always be available, the proposed training curriculum includes a mix of episodes with and without feedback. The results show that this approach improves the agent's performance, even in the absence of feedback.Comment: Accepted at the ICRA Workshop for Communicating Robot Learning across Human-Robot Interactio

Targeted DNA demethylation of the Arabidopsis genome using the human TET1 catalytic domain.

DNA methylation is an important epigenetic modification involved in gene regulation and transposable element silencing. Changes in DNA methylation can be heritable and, thus, can lead to the formation of stable epialleles. A well-characterized example of a stable epiallele in plants is fwa, which consists of the loss of DNA cytosine methylation (5mC) in the promoter of the FLOWERING WAGENINGEN (FWA) gene, causing up-regulation of FWA and a heritable late-flowering phenotype. Here we demonstrate that a fusion between the catalytic domain of the human demethylase TEN-ELEVEN TRANSLOCATION1 (TET1cd) and an artificial zinc finger (ZF) designed to target the FWA promoter can cause highly efficient targeted demethylation, FWA up-regulation, and a heritable late-flowering phenotype. Additional ZF-TET1cd fusions designed to target methylated regions of the CACTA1 transposon also caused targeted demethylation and changes in expression. Finally, we have developed a CRISPR/dCas9-based targeted demethylation system using the TET1cd and a modified SunTag system. Similar to the ZF-TET1cd fusions, the SunTag-TET1cd system is able to target demethylation and activate gene expression when directed to the FWA or CACTA1 loci. Our study provides tools for targeted removal of 5mC at specific loci in the genome with high specificity and minimal off-target effects. These tools provide the opportunity to develop new epialleles for traits of interest, and to reactivate expression of previously silenced genes, transgenes, or transposons

Resveratrol Demonstrates Antimicrobial Effects Against Propionibacterium acnes In Vitro

IntroductionResveratrol (3,5,4'-trihydroxystilbene) is an antioxidant that has multiple biologic effects including antimicrobial properties. Acne vulgaris is a disease of the pilosebaceous unit, characterized by an inflammatory host immune response to the bacteria Propionibacterium acnes (P. acnes). This study sought to determine whether resveratrol may be a potential treatment for acne vulgaris.MethodsColony-forming unit (CFU) assays together with transmission electron microscopy using P. acnes treated with resveratrol or benzoyl peroxide were used to assess antibacterial effects. Blood was drawn from healthy human volunteers, and 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assays were used to assess cytotoxicity in monocytes and keratinocytes.ResultsResveratrol demonstrated sustained antibacterial activity against P. acnes, whereas benzoyl peroxide, a commonly used antibacterial treatment for acne, demonstrated a short-term bactericidal response. A combination of resveratrol and benzoyl peroxide showed high initial antibacterial activity and sustained bacterial growth inhibition. Electron microscopy of P. acnes treated with resveratrol revealed altered bacterial morphology, with loss of membrane definition and loss of well-defined extracellular fimbrial structures. Resveratrol was less cytotoxic than benzoyl peroxide.ConclusionThe sustained antibacterial activity and reduced cytotoxicity versus benzoyl peroxide demonstrated by resveratrol in this study highlight its potential as a novel therapeutic option or adjuvant therapy in the treatment of acne vulgaris

Teachers’ and Students’ Views of Using an AI-Aided Educational Platform for Supporting Teaching and Learning at Chinese Schools

In Chinese schools in less advanced places, there is an urgent need to improve the quality of education and educational equity. This study aims to investigate how an AI-aided educational platform can be used to provide additional teaching and learning resources to serve this need. The AI-aided educational platform used in this study is called Smart-Learning Partner (SLP), which is based on AI technology to provide new opportunities for personalized learning and more educational resources. A qualitative research method was applied in this study. We interviewed and surveyed 98 students and 32 teachers at 9 Chinese schools located in less developed areas. We used content analysis to interpret the findings based on students’ and teachers’ experiences of using the SLP platform. The data demonstrated that this kind of AI-aided educational platform was viewed by students and teachers as a useful tool in students’ learning and teachers’ work. It provided additional possibilities to students and teachers with its rich assessment tools, personalized and overall student learning analysis reports, plentiful high-quality mini-lecture videos, and recommendations from the platform based on the students’ needs for further enhancement study. However, challenges still exist. Adequate electronic devices for students are needed, especially in schools in less developed areas. Students and teachers called for user-friendly interfaces and features, social interaction aspects, and gamification mechanisms with recent online learning platforms. We conclude that based on the teachers’ and students’ views, AI-aided education platforms are useful tools for supporting teaching and learning in Chinese school