High-Performance Ideal Lattice-Based Cryptography on 8-Bit AVR Microcontrollers

Liu, Zhe,Pö,ppelmann, Thomas,Oder, Tobias,Seo, Hwajeong,Roy, Sujoy Sinha,Gü,neysu, Tim,Großschä,dl, Johann,Kim, Howon,Verbauwhede, Ingrid Association for Computing Machinery 2017 ACM transactions on embedded computing systems Vol.16 No.4

<P>Over recent years lattice-based cryptography has received much attention due to versatile average-case problems like Ring-LWE or Ring-SIS that appear to be intractable by quantum computers. In this work, we evaluate and compare implementations of Ring-LWE encryption and the bimodal lattice signature scheme (BLISS) on an 8-bit Atmel ATxmega128 microcontroller. Our implementation of Ring-LWE encryption provides comprehensive protection against timing side-channels and takes 24.9ms for encryption and 6.7ms for decryption. To compute a BLISS signature, our software takes 317ms and 86ms for verification. These results underline the feasibility of lattice-based cryptography on constrained devices.</P>

<i>In situ</i> observation of H₂ dissociation on the ZnO (0001) surface under high pressure of hydrogen using ambient-pressure XPS

Mun, Bongjin S.,Liu, Zhi,Motin, Md Abdul,Roy, Probir C.,Kim, Chang Min Elsevier 2018 International journal of hydrogen energy Vol.43 No.18

<P><B>Abstract</B></P> <P>The interaction of H<SUB>2</SUB> molecules with a ZnO (0001) single crystal surface has been studied over a wide pressure (10<SUP>−6</SUP>–0.25 Torr) and temperature (300–600 K) range using ambient pressure X-ray photoelectron spectroscopy (AP-XPS). ZnO is well-known for interstitial hydrogen and hydrogen atoms in ZnO are believed to be incorporated by the dissociative adsorption of H<SUB>2</SUB> molecules in the atmosphere and their subsequent diffusion into the bulk. The dissociative adsorption of H<SUB>2</SUB> has been investigated at elevated pressures because H<SUB>2</SUB> molecules are not dissociated on the ZnO single crystal surface under ultrahigh vacuum (UHV) conditions. When the pressure is increased to several mTorr, the dissociative adsorption of H<SUB>2</SUB> takes place to form OH bonds on the surface. At 0.25 Torr, the ZnO surface is saturated with H atoms and the coverage is estimated to be 1.1 × 10<SUP>15</SUP> atoms/cm<SUP>2</SUP> at 300 K. At higher surface temperatures, the equilibrium between the dissociative adsorption of gas-phase H<SUB>2</SUB> molecules and the associative desorption of surface H atoms is established. While maintaining the equilibrium, the surface has been monitored successfully <I>in situ</I> by utilizing AP-XPS.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Surface OH bond on ZnO under hydrogen environment has been characterized. </LI> <LI> The surface was monitored <I>in situ</I> over a wide pressure range using AP-XPS. </LI> <LI> Pressure plays an import role for the dissociation of H<SUB>2</SUB> on ZnO. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Tissue Expanders in Staged Calvarial Reconstruction: A Systematic Review

Andrea Y. Lo,Roy P. Yu,Anjali C. Raghuram,Michael N. Cooper,Holly J. Thompson,Charles Y. Liu,Alex K. Wong 대한성형외과학회 2022 Archives of Plastic Surgery Vol.49 No.6

Cranioplasties are common procedures in plastic surgery. The use of tissue expansion (TE) in staged cranioplasties is less common. We present two cases of cranioplasties with TE and systematically review literature describing the use of TE in staged cranioplasties and postoperative outcomes. A systematic review was performed by querying multiple databases. Eligible articles include published case series, retrospective reviews, and systematic reviews that described use of TE for staged bony cranioplasty. Data regarding study size, patient demographics, preoperative characteristics, staged procedure characteristics, and postoperative outcomes were collected. Of 755 identified publications, 26 met inclusion criteria. 85 patients underwent a staged cranioplasty with TE. Average defect size was 122 cm2, and 30.9% of patients received a previous reconstruction. Average expansion period was 14.2 weeks. The most common soft tissue closures were performed with skin expansion only (75.3%), free/pedicled flap (20.1%), and skin graft (4.7%). The mean postoperative follow-up time was 23.9 months. Overall infection and local complication rates were 3.53 and 9.41%, respectively. The most common complications were cerebrospinal fluid leak (7.1%), hematoma (7.1%), implant exposure (3.5%), and infection (3.5%). Factors associated with higher complication rates include the following: use of alloplastic calvarial implants and defects of congenital etiology (p¼0.023 and 0.035, respectively). This is the first comprehensive review to describe current practices and outcomes in staged cranioplasty with TE. Adequate soft tissue coverage contributes to successful cranioplasties and TE can play a safe and effective role in selected cases.

Development of devices and methods for simulation of hurricane winds in a full-scale testing facility

Huang, Peng,Chowdhury, Arindam Gan,Bitsuamlak, Girma,Liu, Roy Techno-Press 2009 Wind and Structures, An International Journal (WAS Vol.12 No.2

The International Hurricane Research Center (IHRC) at Florida International University (FIU) is pursuing research to better understand hurricane-induced effects on residential buildings and other structures through full-scale aerodynamic and destructive testing. The full-scale 6-fan Wall of Wind (WoW) testing apparatus, measuring 4.9 m tall by 7.3 m wide, is capable of generating hurricane-force winds. To achieve windstorm simulation capabilities it is necessary to reproduce mean and turbulence characteristics of hurricane wind flows. Without devices and methods developed to achieve target wind flows, the full-scale WoW simulations were found to be unsatisfactory. To develop such devices and methods efficiently, a small-scale (1:8) model of the WoW was built, for which simulation devices were easier and faster to install and change, and running costs were greatly reduced. The application of such devices, and the use of quasiperiodic fluctuating waveforms to run the WoW fan engines, were found to greatly influence and improve the turbulence characteristics of the 1:8 scale WoW flow. Reasonable reproductions of wind flows with specified characteristics were then achieved by applying to the full-scale WoW the devices and methods found to be effective for the 1:8 scale WoW model.

Boosting capacitive performance of manganese oxide nanorods by decorating with three-dimensional crushed graphene

Reaz Akter Hossain,Saha Shimul,Roy Chanchal Kumar,Wahab Md Abdul,Will Geoffrey,Amin Mohammed A.,Yamauchi Yusuke,Liu Shude,Kaneti Yusuf Valentino,Hossain Md. Shahriar,Firoz Shakhawat H. 나노기술연구협의회 2022 Nano Convergence Vol.9 No.10

This work reports the rational design of MnOx nanorods on 3D crushed reduced graphene oxide (MnOx/C-rGO) by chemical reduction of Ni-incorporated graphene oxide (GO) followed by chemical etching to remove Ni. The resulting MnOx/C-rGO composite synergistically integrates the electronic properties and geometry structure of MnOx and 3D C-rGO. As a result, MnOx/C-rGO shows a significantly higher specific capacitance (Csp) of 863 F g−1 than MnOx/2D graphene sheets (MnOx/S-rGO) (373 F g−1) and MnOx (200 F g−1) at a current density of 0.2 A g−1. Furthermore, when assembled into symmetric supercapacitors, the MnOx/C-rGO-based device delivers a higher Csp (288 F g−1) than MnOx/S-rGO-based device (75 F g−1) at a current density of 0.3 A g−1. The superior capacitive performance of the MnOx/C-rGO-based symmetric device is attributed to the enlarged accessible surface, reduced lamellar stacking of graphene, and improved ionic transport provided by the 3D architecture of MnOx/C-rGO. In addition, the MnOx/C-rGO-based device exhibits an energy density of 23 Wh kg−1 at a power density of 113 Wkg−1, and long-term cycling stability, demonstrating its promising potential for practical application.

Development of devices and methods for simulation of hurricane winds in a full-scale testing facility

Peng Huang,Arindam Gan Chowdhury,Girma Bitsuamlak,Roy Liu 한국풍공학회 2009 Wind and Structures, An International Journal (WAS Vol.12 No.2

The International Hurricane Research Center (IHRC) at Florida International University (FIU) is pursuing research to better understand hurricane-induced effects on residential buildings and other structures through full-scale aerodynamic and destructive testing. The full-scale 6-fan Wall of Wind (WoW) testing apparatus, measuring 4.9 m tall by 7.3 m wide, is capable of generating hurricane-force winds. To achieve windstorm simulation capabilities it is necessary to reproduce mean and turbulence characteristics of hurricane wind flows. Without devices and methods developed to achieve target wind flows, the full-scale WoW simulations were found to be unsatisfactory. To develop such devices and methods efficiently, a small-scale (1:8) model of the WoW was built, for which simulation devices were easier and faster to install and change, and running costs were greatly reduced. The application of such devices, and the use of quasiperiodic fluctuating waveforms to run the WoW fan engines, were found to greatly influence and improve the turbulence characteristics of the 1:8 scale WoW flow. Reasonable reproductions of wind flows with specified characteristics were then achieved by applying to the full-scale WoW the devices and methods found to be effective for the 1:8 scale WoW model.

Structural, Electrical, and Optical Properties of CdMnTe Crystals Grown by Modified Floating-Zone Technique

Ge Yang,Genda Gu,Aleksey E. Bolotnikov,Yonggang Cui,Giuseppe S. Camarda,Anwar Hossain,Utpal N. Roy,Nicholas Kivi,Tiansheng Liu,Ralph B. James 대한금속·재료학회 2015 ELECTRONIC MATERIALS LETTERS Vol.11 No.3

Cadmium manganese telluride (CdMnTe or CMT), a compound semiconductor, is considered a promising material for the fabrication of high-performance room-temperature x-ray and gamma-ray detectors. The presence of material defects, e.g., high density of Te inclusions, has been a long-standing issue in CMT crystals grown by various Bridgman methods, since these defects degrade the device performance via charge-trapping. To address this issue, we employed the modified floating-zone method (MFZ) to grow CMT crystals and obtained as-grown crystals free of Te inclusions. This represents a new and distinct feature, absence of Te inclusions, compared to CMT crystals grown by Bridgman methods. White-beam x-ray diffraction topography (WBXDT) measurements demonstrated the existence of a high stress field within the MFZ-grown CMT crystals, which originates from the steep temperature gradient near the growth interface. Furthermore, we achieved a resistivity of 109 Ωcm for the MFZ-grown CMT crystals. The low-temperature photoluminescence (PL) measurements show that the intensity of the dislocation-related Y band is much higher than that of the principal exciton peaks, (D0,X) and (A0,X), confirming that the crystalline quality is affected by the high stress field. A long-term in-situ or post-growth thermal annealing will help to release such stress to improve the crystalline quality.