316 research outputs found

    The block cipher NSABC (public domain)

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    We introduce NSABC/w -- Nice-Structured Algebraic Block Cipher using w-bit word arithmetic, a 4w-bit analogous of Skipjack [NSA98] with 5w-bit key. The Skipjack's internal 4-round Feistel structure is replaced with a w-bit, 2-round cascade of a binary operation (x,z)\mapsto(x\boxdot z)\lll(w/2) that permutes a text word x under control of a key word z. The operation \boxdot, similarly to the multiplication in IDEA [LM91, LMM91], bases on an algebraic group over w-bit words, so it is also capable of decrypting by means of the inverse element of z in the group. The cipher utilizes a secret 4w-bit tweak -- an easily changeable parameter with unique value for each block encrypted under the same key [LRW02] -- that is derived from the block index and an additional 4w -bit key. A software implementation for w=64 takes circa 9 clock cycles per byte on x86-64 processors.Comment: 22 pages, 4 figure

    Self-Centering Prestressed Concrete Pier Considering the Effect of Vertical Earthquake Motions with External Aluminum Dissipators

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    A prototype self-centering prestressed concrete (SCPC) bridge pier and conventional reinforced concrete (RC) pier with similar backbone curves are designed and modeled. The objective of this study is to investigate the seismic performance of the SCPC bridge pier considering the effect of vertical earthquake ground motions. Under a severe vertical earthquake motion, the RC pier damage is much greater than the SCPC pier. The SCPC bridge pier shows a great capability in reducing residual drift at the top of the structure, therefore, the probability of bridge survival is increased. In this study, the external aluminum bars were used to reduce the seismic energy impacts on the bridge pier structure. In addition, The averages of the maximum and residual drifts of bridge piers under a set of 20 earthquake ground motion records impact with different vertical-to-horizontal peak acceleration ratios on the bridge seismic response are presented. The results are compared with the case of horizontal-only excitations, to clarify the effect of the vertical earthquake on the SCPC and RC bridge pier. Hence, the designers can find good solutions for structures in earthquakes resistance

    THE APPLICATION OF GENERAL ENDURANCE EXERCISES TO IMPROVE 3000-METER ARMED RUNS OF MALE MILITIA FORCES AGED 25-28 IN HO CHI MINH CITY, VIETNAM

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    A 3000-meter run with guns, a common physical exercise to train endurance in military force, is one of the training and competition contents for male soldiers of the Vietnam People's Armed Forces in general and militia forces in particular. The purpose of this study was to build up a general endurance exercise for male militia forces aged 25-28 in Ho Chi Minh City. Independent samples t-test was used to compare the difference between the experimental and control groups, while Paired sample t-test was used to identify the difference between the pre- and post-experimental. By using the general methods in sport, 12 general endurance exercises were selected and applied for male militia forces in 3000-meter armed runs. Besides, the result showed that there was a significant difference between the two groups (the experimental group had higher scores when compared with the control one) after eight weeks of training.  Article visualizations

    Abelian charge inspired by family number

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    Quark has an electric charge either −1/3-1/3 or 2/32/3 and a baryon number 1/31/3, where the divisions 33's match the color number. Although the electric charge and the baryon number have a nature distinct from the color charge, the matching is necessary for the standard model or a relevant B−LB-L extension consistent at quantum level, since the relevant anomaly [SU(2)L]2U(1)A[SU(2)_L]^2U(1)_A for A=YA=Y or B−LB-L must vanish. If elementary particles have a new U(1)U(1) charge differently from AA, such anomaly is not cancelled for each family. However, if we demand that the anomaly is cancelled over all families, this relates the color number to the family number instead of the electric charge and baryon number, and interestingly the family number guides us to a novel U(1)U(1) theory. We will discuss the implication of this theory for neutrino mass, recent WW-boson mass anomaly, FCNC, and particle colliders.Comment: 20 pages, 2 figure

    How Foreign Ownership and Competition Affect the Credit Growth of Commercial Banks: Evidence from A Transitional Economy

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    This study examines the relationship between foreign ownership and market competition, proxied by bank market power, affecting the credit growth of 32 commercial banks in Vietnam from 2010 to 2020. The Random Effects Model and the Dynamic System Generalized Method of Moments were used to analyze an unbalanced panel of 278 annual observations. The findings report that foreign ownership reduces credit growth, with each percentage increase in foreign ownership reducing credit growth by 0.74%. The results indicate an inverse U-shaped relationship between competitive advantage and credit growth, with a turning point of 0.46. The main findings were found to be robust after employing an alternative market power proxy. The study recommends that bank managers and policymakers limit foreign ownership and control commercial banks’ market power to promote sustainable credit growth

    Catalytic Dye Oxidation over CeO2 Nanoparticles Supported on Regenerated Cellulose Membrane

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    A novel regenerated cellulose (RC) membrane containing cerium oxide (CeO2) nanoparticles is described in detail. In this work, CeO2 nanoparticles with high surface area and mesoporosity were prepared by a modified template-assisted precipitation method. Successful synthesis was achieved using cerium nitrate as a precursor, adjusting the final pH solution to around 11 by ammonium hydroxide and ethylene diamine, and annealing at 550 °C for 3 hours under a protective gas flow. This resulted in a surface area of 55.55 m².g–1 for the nanoparticles. The regenerated cellulose membrane containing CeO2 particles was synthesized by the novel and environmentally friendly method. The catalyst CeO2 and cellulose/CeO2 membrane were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Electron paramagnetic resonance (EPR), and Brunauer-Emmett-Teller (BET) measurements. The g-value of 2.276 has confirmed the presence of the surface superoxide species of CeO2 nanoparticles in EPR. The photocatalytic activity of the catalyst and the membrane containing the catalyst was evaluated through the degradation of methylene blue under visible light irradiation by UV-VIS measurements. The cellulose/CeO2 membrane degraded 80% of the methylene blue solution in 120 minutes, showing a better photocatalytic activity than the CeO2 catalyst, which degraded approximately 62% in the same period. It has been proven that the RC membrane is not only a good transparent supporting material but also a good adsorption for high-performance of CeO2 catalyst. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

    Genetic diversity of two successive generations of selection in bighead catfish (Clarias macrocephalus) populations

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    Selective programs associated with domestication can improve fish production but also can have an impact on broodstock’s genetic diversity. In this study, the genetic diversity of original sources (G0) from wild and cultured bighead catfish populations, as well as the two successive generations (G1 and G2) subjected to selection experiments, was assessed. G0 wild adults were collected in Ca Mau conservation area and G0 cultured fish were from a hatchery in Can Tho. The G1 fish included pure crosses and crossbreeds of G0, while G2 was the offspring of the selected G1. Fin clips from 27 to 29 individuals of each fish group were randomly sampled for genetic analysis. The amplification results using six ISSR primers showed that the genetic diversity was relatively higher in G0 (effective number of alleles Ne from 1.43 to 1.49; heterozygosity He from 0.265 to 0.290) than in G1 (Ne = 1.32±0.04; He = 0.201±0.023) and G2 (Ne = 1.34±0.04; He = 0.216±0.023). Genetic differences increased between the original populations and the descending generations. To reduce the detrimental impacts of low genetic diversity in domesticated bighead catfish in the Mekong Delta, it is recommended that broodstock in later generations should be produced in a larger..

    RESEARCH ON THE MANUFACTURING MAGNESIUM FROM THANHHOA DOLOMITE BY PIDGEON PROCESS

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    The magnesium and magnesium alloys has applied widely in different industrial aspects in Vietnam in the modern life. Especially, the products from magnesium alloys implementing in the automotive have increased rapidly since the car elements tend to be generated by the light alloys in order to save the fuel. However, in the current time, Vietnam has no factories to produce the magnesium to adapt the domestic demand although it owns an enrich resource of raw materials. This research indicates the possibility of using the dolomite ore in Thanhhoa – Vietnam to make the magnesium as well as evaluate the primary factors like recovering temperature, reducing agent rate, recovering time having effect on the reduction efficiency of Thanhhoa dolomite by metallothermic method in vacuum (Pidgeon Process). This is basic process, low investment and suitable for the small and medium scales in Vietnam. The experiment includes heating, indicating the chemical ingredients and recovering experiment on the dolomite after calcination (dolime) by using ferrosilicon. The thermodynamic model is created to estimate the recovering efficiency in the Pidgeon. The result shows that the CaO/MgO molar ratio of calcination dolomite in Thanhhoa is nearly 1.5 which is suitable to produce magnesium in the case of highly-required efficiency and pureness. Besides, the result from the furnace of the experiment is lower than the one in the model. The samples are set up to check the influence of the rate of ferrosilicon in the compound. The result indicates that the ideal efficiency reaches 85 % with 30 % ferrosilicon. Moreover, the study confirms that the optimal operating conditions in this process are recovering during three hours at 1200 °C and 100 Pa pressure. This result proves the potential application of Thanhhoa dolomite in the industry suitable with the current condition in Vietna

    HUPSMT: AN EFFICIENT ALGORITHM FOR MINING HIGH UTILITY-PROBABILITY SEQUENCES IN UNCERTAIN DATABASES WITH MULTIPLE MINIMUM UTILITY THRESHOLDS

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    The problem of high utility sequence mining (HUSM) in quantitative se-quence databases (QSDBs) is more general than that of frequent sequence mining in se-quence databases. An important limitation of HUSM is that a user-predened minimum tility threshold is used commonly to decide if a sequence is high utility. However, this is not convincing in many real-life applications as sequences may have diferent importance. Another limitation of HUSM is that data in QSDBs are assumed to be precise. But in the real world, collected data such as by sensor maybe uncertain. Thus, this paper proposes a framework for mining high utility-probability sequences (HUPSs) in uncertain QSDBs (UQS-DBs) with multiple minimum utility thresholds using a minimum utility. Two new width and depth pruning strategies are also introduced to early eliminate low utility or low probability sequences as well as their extensions, and to reduce sets of candidate items for extensions during the mining process. Based on these strategies, a novel ecient algorithm named HUPSMT is designed for discovering HUPSs. Finally, an experimental study conducted in both real-life and synthetic UQSDBs shows the performance of HUPSMT in terms of time and memory consumption

    The Nonlinearity of Working Capital and Cross-Sectional Stock Returns: Does Financial Constraints Matter?

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    This study is the first to examine the impacts of working capital (WC) and financial constraints on cross-sectional stock returns in Taiwan. The findings indicate a non-linear relationship between WC and stock returns. Moreover, the nonlinearity between WC and cross-sectional stock returns is robust after controlling for financial constraints, risk, and growth factors, before the Covid-19 pandemic. In contrast, there is no evidence of nonlinearity between WC and stock returns throughout the Covid-19 outbreak. In addition, the study shows that any deviations from the minimum WC level enhance the stock returns cross-sectionally. It is found that a positive Deviation effect exists in the Taiwan stock exchange before the Covid-19 pandemic by employing portfolio sorting methodologies. The return difference of the long buying highest Deviation and short selling lowest Deviation portfolios earn from 0.6% to 0.9% per month after controlling for financial constraints, risks, and growth factors. Interestingly, it is determined that the deviation effect becomes negative for small stocks during the Covid-19 pandemic, implying that investors prefer small stocks to maintain minimum working capital. The results support the trade-off theory and liquidity preference theory. Finally, the study provides insights into working capital management for managers, and investment strategies for investors during the pandemic
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