The need to support various digital signal processing (DSP) and classification applications on energy-constrained devices has steadily grown. Such applications often extensively perform matrix ...multiplications using fixed-point arithmetic while exhibiting tolerance for some computational errors. Hence, improving the energy efficiency of multiplications is critical. In this brief, we propose multiplier architectures that can tradeoff computational accuracy with energy consumption at design time. Compared with a precise multiplier, the proposed multiplier can consume 58% less energy/op with average computational error of \sim 1 %. Finally, we demonstrate that such a small computational error does not notably impact the quality of DSP and the accuracy of classification applications.
Abstract
This paper reports the crystallization kinetics of (Cu
60
Zr
25
Ti
15
)
99.3
Nb
0.7
bulk metallic glass under isothermal conditions. Differential scanning calorimetry (DSC) has been employed ...for isothermal annealing at ten different temperatures prior to the onset of crystallization (
T
o
) temperature. X-ray diffraction and transmission electron microscopy have been used to confirm the amorphous structure of the as cast sample. Crystallized volume fractions (
x
) are calculated from the exothermic peaks of DSC scans. Crystallized volume fractions (
x
) against time show sigmoidal type of curves as well as the curves become steeper at higher annealing temperatures. Continuous heating transformation diagram has been simulated to understand the stability of the bulk metallic glass. Crystallization kinetics parameters are calculated using Arrhenius and Johnson–Mehl–Avrami equations. Activation energy (
E
a
) and Avrami exponential factor (
n
) have exhibited strong correlation with crystallized volume fraction (
x
). The average activation energy for isothermal crystallization is found to be 330 ± 30 kJ/mol by Arrhenius equation. Nucleation activation energy (
E
nucleation
) is found to be higher than that of growth activation energy (
E
growth
). The Avrami exponential factor (
n
) indicates about the diffusion controlled mechanism of the nucleation and three-dimensional growth.
For Pb-free 35B
2
O
3
‒35Bi
2
O
3
‒(30–
x
)TeO
2
‒(
x
)BaO (
x
= 5, 10, 15, 20, and 25 mol%) and (90–
x
)TeO
2
‒10Bi
2
O
3
‒(
x
)BaO (
x
= 10, 15, and 20 mol%) glass systems, gamma and neutron ...(both fast and thermal neutron) radiation shielding features were examined and compared. Within 0.015–15 MeV photon energy, mass attenuation coefficients (
μ
/
ρ
), for all samples, which have been assessed using WinXCOM program are in fair agreement with deduced MCNP5 simulation code
μ/ρ
results. For all selected samples, at the lowest energy,
μ
/
ρ
has bigger values whereas at higher energy regions possess lower values. Furthermore, by employing
μ
/
ρ
values, effective atomic number (
Z
eff
), effective electron density (
N
eff
), half-value layer (HVL), tenth-value layer (TVL), and mean free path (MFP) are figured out for both glass systems. For studied samples, with the gradual replacement of TeO
2
content with BaO, the derived values of
Z
eff
, HVL, TVL, and MFP revealed improved γ-ray shielding potentiality. Besides, within photon energy range of 0.015–15 MeV, exposure build-up factors (EBFs) and energy absorption build-up factors (EABFs) were estimated for all samples by utilizing G‒P fitting method as a function of different penetration depths (0.5, 1, 2, 3, 4, 5, 6, 7, 8, 10, 15, 20, 25, 30, 35, and 40 mfp). The 35B
2
O
3
–35Bi
2
O
3
–5TeO
2
–25BaO (mol%) glass relatively larger
μ
/
ρ
and
Z
eff
values, lower HVL, TVL, and MFP values, and minimal EBF and EABF values confirm its superior γ-ray attenuation competence among all samples. Additionally, in comparison, HVL and MFP values of 35B
2
O
3
–35Bi
2
O
3
–5TeO
2
–25BaO (mol%) sample are lower than the respective values of some commercial γ-ray shielding glasses and different types of standard concretes, signifying its better shielding features than them. Moreover, macroscopic removal cross-section for fast neutrons (
Σ
R
), coherent scattering cross-section (
σ
cs
), incoherent scattering cross-section (σ
ics
), absorption cross-section (
σ
A
), and total cross-section (
σ
T
) for thermal neutrons absorption were derived for both glass systems. Among all selected glasses, 35B
2
O
3
–35Bi
2
O
3
–5TeO
2
–25BaO (mol%) sample possesses relatively higher
Σ
R
(0.106 cm
−1
) and ‘
σ
T
’ (8.809 cm
−1
at 0.0253 eV neutron energy) values for fast and thermal neutrons attenuation, respectively, demonstrating its favorable absorption capability for neutrons.
Gamma-rays and fast and thermal neutron attenuation features of (Bi
2
O
3
)
x
–(TeO
2
)
(100−
x
)
(where
x
= 5, 8, 10, 12, and 15 mol%) and (TeO
2
)
0.7
–(B
2
O
3
)
0.3
(1−
x
)
–(Bi
2
O
3
)
x
...(where
x
= 0.05, 0.10, 0,15, 0.20, 0.25, and 0.3 mol%) glass systems have been explored and compared. For all samples, mass attenuation coefficients (
μ
/
ρ
) are estimated within 0.015–15 MeV photon energy range by MCNP5 simulation code and correlated with WinXCom results, which showed a satisfactory agreement between computed
μ
/
ρ
values by these both methods. Additionally, effective atomic number (
Z
eff
), effective electron density (
N
eff
), half-value layer (HVL), tenth-value layer (TVL), mean free path (MFP), total atomic cross-section (
σ
a
), and total electronic cross-section (
σ
e
) are calculated by utilizing
μ
/
ρ
values. The
μ
/
ρ
,
Z
eff
, and
N
eff
are energy dependent and have higher values at the lowest energy and smaller values at higher energies. Moreover, using the G–P fitting method as a function of penetration depth (up to 40 mfp) and incident photon energy (0.015–15 MeV range), exposure buildup factors (EBFs) and energy absorption buildup factors (EABFs) are evaluated. Both 85TeO
2
–15Bi
2
O
3
(mol%) and 49TeO
2
–21B
2
O
3
–30Bi
2
O
3
(mol%) samples, by possessing higher values of
Z
eff
, exhibit minimum EBF and EABF values. Highest
μ
/
ρ
,
Z
eff
values and lowest HVL, TVL, MFP values of 49TeO
2
–21B
2
O
3
–30Bi
2
O
3
(mol%) sample indicated its better gamma-ray absorption capability among all selected glasses. Further, macroscopic effective removal cross-section for fast neutrons (Σ
R
), coherent scattering cross-section (
σ
cs
), incoherent scattering cross-section (
σ
ics
), absorption cross-section (
σ
A
), and total cross-section (
σ
T
) values for thermal neutron attenuation have been computed. Among all samples, 49TeO
2
–21B
2
O
3
–30Bi
2
O
3
(mol%) glass possesses a better Σ
R
value for fast neutron attenuation, while the largest ‘
σ
T
’ value of 66.5TeO
2
–28.5B
2
O
3
–5Bi
2
O
3
(mol%) sample suggests its good thermal neutron absorption efficiency.
An attempt has been made on a constructive approach to evaluate the performance of snail shell ash (SSA) for its corrosion performance under marine environments. Corrosion performance of steel rebar ...in chloride-contaminated SSA with (0% to 50%) replacement levels of cement extract medium was examined through electrochemical and weight loss techniques. Initially, snail shell powder (SSP) is made by pulverizing and subsequently SSA is by thermal decomposition methods. Both SSP and SSA were characterized by X-ray diffraction, Fourier transforms infrared spectroscopy, scanning electron microscopy, and energy dispersion X-ray spectroscopy. Concrete cubes with 0% to 50% replacement levels of cement by SSA were evaluated for their mechanical properties. A critical level of 20 to 30% SSA improved both corrosion resistance and strength of concrete. Extrapolation modeling for the strength and corrosion rate with respect to later age were made. SSA is a suitable replacement material for natural limestone in cement productions.
Traffic jams often occur without any obvious reasons such as traffic accidents, roadwork, or closed lanes. Under moderate to high traffic density, minor perturbations to traffic flow (e.g., a strong ...braking motion) are easily amplified into a wave of stop-and-go traffic. This is known as a phantom jam. In this paper, we aim to mitigate phantom jams leveraging the three-phase traffic theory and vehicle-to-vehicle (V2V) communication. More specifically, an efficient phantom jam control protocol is proposed in which a fuzzy inference system is integrated with a V2V-based phantom jam detection algorithm to effectively capture the dynamics of traffic jams. Per-lane speed difference under traffic congestion is taken into account in the protocol design, so that a phantom jam is controlled separately for each lane, improving the performance of the proposed protocol. We implemented the protocol in the Jist/SWAN traffic simulator. Simulations with artificially generated traffic data and real-world traffic data collected from vehicle loop detectors on Interstate 880, California, USA, demonstrate that our approach has by up to 9% and 4.9% smaller average travel times (at penetration rates of 10%) compared with a state-of-the-art approach, respectively.
Distracted driving jeopardizes the safety of the driver and others. Numerous solutions have been proposed to prevent distracted driving, but the number of related accidents has not decreased. Such a ...deficiency comes from fragile system designs where drivers are detected exploiting sensory features from strictly controlled vehicle-riding actions and unreliable driving events. We propose a system called ADDICT (Accurate Driver Detection exploiting Invariant Characteristics of smarTphone sensors), which identifies the driver utilizing the inconsistency between gyroscope and magnetometer dynamics and the interplay between electromagnetic field emissions and engine startup vibrations. These features are invariantly observable regardless of smartphone positions and vehicle-riding actions. To evaluate the feasibility of ADDICT, we conducted extensive experiments with four participants and three different vehicles by varying vehicle-riding scenarios. Our evaluation results demonstrated that ADDICT identifies the driver's smartphone with 89.1% average accuracy for all scenarios and >85% under the extreme scenario, at a marginal cost of battery consumption.
Amorphous structures of the as-cast bulk metallic glass samples (BMGs) of Cu
60
Zr
25
Ti
15
and (Cu
60
Zr
25
Ti
15
)
95
Ni
5
alloys are confirmed by X-ray diffraction. Isothermal crystallization ...kinetics of these BMGs are investigated using differential scanning calorimetry. For both the alloys, the apparent activation energy (
E
a
) shows a strong dependency on crystallization volume fraction (
x
). Isothermal crystallization kinetic parameters are calculated by Arrhenius and Johnson–Mehl–Avrami equations. Avrami exponential factor (
n
) is also found to show clear correlation with the crystallization volume fraction (
x
). It is found that the crystallization process is easier in Cu
60
Zr
25
Ti
15
BMG than in (Cu
60
Zr
25
Ti
15
)
95
Ni
5
BMG as the
E
a
decreases constantly for the former alloy though in the case of second alloy, the
E
a
is almost unchanged up to
x
= 60%. For both the alloys, nucleation activation energy (
E
nucleation
) is found to be higher than that of growth activation energy (
E
growth
). This indicates that the growth of crystals during isothermal crystallization in these glasses is easier than nucleation, and the minor addition of Ni causes the higher thermal stability against crystallization in isothermal condition.
In the present study, different contents, i.e., 1–3% of 0.5 M ammonium phosphate mono basic (APMB), were used as corrosion inhibitor to reduce the corrosion of steel rebar. Electrochemical impedance ...spectroscopy (EIS) results showed that up to 24 h of exposure, polarization resistance (Rp) and passive/oxide film resistance (Ro) gradually decreased in simulated concrete pore (SCP) + 3.5 wt.% NaCl solution owing to the reduction in pH of the solution. The steel rebar exposed in 2% inhibitor containing SCP + 3.5 wt.% NaCl solution exhibited 90% inhibition efficiency after 1 h of exposure. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy confirmed the formation of thermodynamically very stable and sparingly soluble goethite (α-FeOOH), maghemite (γ-Fe2O3), and iron phosphate (FePO4) as passive/oxide film onto the steel rebar surface exposed to 2% inhibitor containing SCP + 3.5 wt.% NaCl solution.
With the emergence of smart and converged home services, the need for the secure and easy interplay of various devices has been increased. Push Button Configuration (PBC) is one of the technologies ...proposed for easy set-up of a secure session between IT and consumer devices. Although the Wi-Fi Direct specification explicitly states that all devices must support the PBC method, its applicability is very limited. This is because the security vulnerability of PBC can be maliciously exploited so that attackers can make illegitimate sessions with consumer devices. To address this problem, this paper proposes a novel Security-enhanced PBC (SePBC) scheme with which we can uncover suspicious or malicious devices. The proposed mechanism has several unique features. First, we develop a secure handshake distance measurement protocol by preventing an adversary sitting outside the region from maliciously manipulating its distance to be fake. Second, it is compatible with the original Wi-Fi PBC without introducing a brand-new methodology. Finally, SePBC uses lightweight operations without CPU-intensive cryptography computation and employs inexpensive H/W. Moreover, it needs to incur little overhead when there is no attack. This paper also designs and implements the proposed SePBC in the real world. Our experimental results and analysis show that the proposed SePBC scheme effectively defeats attacks on PBC while minimizing the modification of the original PBC equipment.
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