51 research outputs found
Measuring the Mobile User Experience: Conceptualization and Empirical Assessment
User experience is commonly considered important for IT adoption and use. However, a formal measure that captures a user’s holistic experience obtained through the use of an IT artifact has not been developed. In this study, we propose a new measure of user experience and examine its validity using the data collected from over 240 smartphone mobile users in South Korea. Based on prior research on brand experience in marketing, we conceptualize user experience as a second order construct with four sub-dimensions. The convergent and discriminant validity of the measurement items of mobile user experience is examined along with the established measurement items of the cognitive absorption, which is similar to the proposed construct in that both capture what a user has experienced while interacting with an IT artifact. Further, we examine the effects of the proposed construct on perceived usefulness, satisfaction, and continuous intention
Oiling-out Crystallization of Beta-Alanine onSolid Surfaces Controlled by Solvent Exchange
Droplet formation in oiling-out crystallization has important implication for
separation and purification of pharmaceutical active ingredients by using an
antisolvent. In this work, we report the crystallization processes of
oiling-out droplets on surfaces during solvent exchange. Our model ternary
solution is beta-alanine dissolved in isopropanol and water mixture. As the
antisolvent isopropanol displaced the alanine solution pre-filled in a
microchamber, liquid-liquid phase separation occurred at the mixing front. The
alanine-rich subphase formed surface microdroplets that subsequently
crystallized with progression of solvent exchange. We find that the flow rates
have significant influence on the droplet size, crystallization process, and
growth rate, and final morphology of the crystals. At fast flow rates the
droplets solidified rapidly and formed spherical-cap structures resembling the
shape of droplets, in contrast to crystal microdomains or thin films formed at
slow flow rates. On a highly hydrophilic surface, the crystals formed thin film
without droplets formed on the surface. We further demonstrated that by the
solvent exchange crystals can be formed by using a stock solution with a very
low concentration of the precursor, and the as-prepared crystals can be used as
seeds to trigger crystallization in bulk solution. Our results suggest that the
solvent exchange has the potential to be an effective approach for controlling
oiling-out crystallization, which can be applied in wide areas, such as
separation and purification of many food, medical, and therapeutic ingredients.Comment: Advanced Materials Interfaces (2020
Compact Implementations of LEA Block Cipher for Low-End Microprocessors
In WISA\u2713, a novel lightweight block cipher named LEA
was released. This algorithm has certain useful features for hardware
and software implementations, i.e., simple ARX operations, non-S-box
architecture, and 32-bit word size. These features are realized in several
platforms for practical usage with high performance and low overheads.
In this paper, we further improve 128-, 192- and 256-bit LEA encryption
for low-end embedded processors. Firstly we present speed optimization
methods. The methods split a 32-bit word operation into four byte-wise
operations and avoid several rotation operations by taking advantages of
efficient byte-wise rotations. Secondly we reduce the code size to ensure
minimum code size.We nd the minimum inner loops and optimize them
in an instruction set level. After then we construct the whole algorithm
in a partly unrolled fashion with reasonable speed. Finally, we achieved
the fastest LEA implementations, which improves performance by 10.9%
than previous best known results. For size optimization, our implemen-
tation only occupies the 280B to conduct LEA encryption. After scaling,
our implementation achieved the smallest ARX implementations so far,
compared with other state-of-art ARX block ciphers such as SPECK and
SIMON
Binary Field Multiplication on ARMv8
In this paper, we show efficient implementations of binary field multiplication over ARMv8.
We exploit an advanced 64-bit polynomial multiplication (\texttt{PMULL}) supported by ARMv8
and conduct multiple levels of asymptotically faster Karatsuba multiplication.
Finally, our method conducts binary field multiplication within 57 clock cycles for B-251.
Our proposed method on ARMv8 improves the performance by a factor of times than previous techniques on ARMv7
Secure Binary Field Multiplication
Binary eld multiplication is the most fundamental building block of binary eld Elliptic Curve Cryptography (ECC) and Galois/Counter Mode (GCM). Both bit-wise scanning and Look-Up Table (LUT) based methods are commonly used for binary eld multiplication. In terms of Side Channel Attack (SCA), bit-wise scanning exploits insecure branch operations which leaks information in a form of timing and power consumption. On the other hands, LUT based method is regarded as a relatively secure approach because LUT access can be conducted in a regular and atomic form. This ensures a constant time solution as well. In this paper, we conduct the SCA on the LUT based binary eld multiplication. The attack exploits the horizontal Correlation Power Analysis (CPA) on weights of LUT. We identify the operand with only a power
trace of binary eld multiplication. In order to prevent SCA, we also suggest a mask based binary eld multiplication which ensures a regular and constant time solution without LUT and branch statements
Effect of Inclination Angle on the Air-Side Performance of Aluminum Parallel Flow Heat Exchangers Under Wet Conditions
Construction of Efficient and Secure Pairing Algorithm and its Application
Abstract. The randomized projective coordinate (RPC) method applied to a pairing computation algorithm is a good solution that provides an efficient countermeasure against side channel attacks. In this study, we investigate measures for increasing the efficiency of the RPC-based countermeasures and construct a method that provides an efficient RPCbased countermeasure against side channel attacks. We then apply our method to the well-known ηT pairing algorithm over binary fields and obtain an RPC-based countermeasure for the ηT pairing; our method is more efficient than the RPC method applied to the original ηT pairing algorithm
- …