• Journal of applied mathematics & informatics
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• v.40 no.5_6
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• pp.1089-1103
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• 2022

This paper focuses on the existence and uniqueness outcome for fractional integro-differential equation (FIDE) among impulsive edge condition and Hyers-Ulam-Rassias Stability (HURS) by using fractional calculus and some fixed point theorem in some weak conditions. The outcome procured in this paper upgrade and perpetuate some studied solutions.

• Bulletin of the Korean Mathematical Society
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• v.61 no.2
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• pp.479-488
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• 2024

Convergence to a steady state in the long term limit is established for global weak solutions to a chemotaxis model with degenerate local sensing and consumption, when the motility function is C¹-smooth on [0, ∞), vanishes at zero, and is positive on (0, ∞). A condition excluding that the large time limit is spatially homogeneous is also provided. These results extend previous ones derived for motility functions vanishing algebraically at zero and rely on a completely different approach.

• Korean Chemical Engineering Research
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• v.57 no.2
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• pp.164-171
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• 2019

The protonation parameters, dissociation constants ($pK_{BH^+}$) of conjugate acid, slope values (m, ${\phi}$ and $m^*$) and correlation coefficients (r) of hydroxamic acids were determined by Hammett acidity function method, Bunnett-Olsen method and excess acidity method in hydrochloric and perchloric acid solutions. Effect of acid concentration on partition and percentage protonation was also studied. $pK_{BH^+}$ values show that hydroxamic acids do not behave as Hammett bases, but hydroxamic acids behave as weak bases in strong acidic solutions. The values of $pK_{BH^+}$ obtained through Bunnett-Olsen method and excess acidity method were compared with the Hammett acidity function. ChemAxon's MarvinSketch 6.1.5 software was also used for determining $pK_a$, pI and microspecies distribution (%) of hydroxamic acids with pH. Hydrogen donor and acceptor values and logD were also obtained. The results show that N-p-chlorophenyl-4-bromobenzohydroxamic acid has the highest $pK_a$ and lowest logD values. On the contrary, N-phenyl-3,5-dinitrobenzohydroxamic acid has lowest the $pK_a$ and highest logD values.

• Journal of Information Processing Systems
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• v.15 no.4
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• pp.904-919
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• 2019

Many security systems rely solely on solutions based on Artificial Intelligence, which are weak in nature. These security solutions can be easily manipulated by malicious users who can gain unlawful access. Some security systems suggest using fingerprint-based solutions, but they can be easily deceived by copying fingerprints with clay. Image-based security is undoubtedly easy to manipulate, but it is also a solution that does not require any special training on the part of the user. In this paper, we propose a multi-factor security framework that operates in a three-step process to authenticate the user. The motivation of the research lies in utilizing commonly available and inexpensive devices such as onsite CCTV cameras and smartphone camera and providing fully secure user authentication. We have used technologies such as Argon2 for hashing image features and physically unclonable identification for secure device-server communication. We also discuss the methodological workflow of the proposed multi-factor authentication framework. In addition, we present the service scenario of the proposed model. Finally, we analyze qualitatively the proposed model and compare it with state-of-the-art methods to evaluate the usability of the model in real-world applications.

• Geomechanics and Engineering
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• v.30 no.4
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• pp.363-372
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• 2022

One of the most frequent issues in tunnel excavation is the collapse of rock blocks and the dropping of rock fragments from the tunnel face. The tunnel face can be reinforced using a number of techniques. One of the most popular and affordable solutions is the use of face longitudinal dowels, which has benefits including high strength, flexibility, and ease of cutting. In order to examine the reinforced face, this work shows the longitudinal deformation profile and ground response curve for a tunnel face. This approach is based on assumptions made during the analysis phase of problem solving. By knowing the tunnel face response and dowel behavior, the interaction of two elements can be solved. The rock element equation derived from the rock bolt method is combined with the dowel differential equation to solve the reinforced ground response curve (GRC). With a straightforward and accurate analytical equation, the new differential equation produces the reinforced displacement of the tunnel face at each stage of excavation. With simple equations and a less involved computational process, this approach offers quick and accurate solutions. The FLAC3D simulation has been compared with the suggested analytical approach. A logical error is apparent from the discrepancies between the two solutions. Each component of the equation's effect has also been described.

• Steel and Composite Structures
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• v.46 no.5
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• pp.709-718
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• 2023

The absence of an important portion of the web plate in steel beams with multiple circular perforations, cellular beams, causes the web plate to undergo distortions prior to and during lateral torsional buckling (LTB). The conventional LTB equations in the codes and literature underestimate the buckling moments of cellular beams due to web distortions. The present study is an attempt to develop analytical methods for estimating the elastic buckling moments of cellular beams. The proposed methods rely on the reductions in the torsional and warping rigidities of the beams due to web distortions and the reductions in the weak-axis bending and torsional rigidities due to the presence of web openings. To test the accuracy of the analytical estimates from proposed solutions, a total of 114 finite element analyses were conducted for six different standard IPEO sections and varying unbraced lengths within the elastic limits. These analyses clearly indicated that the LTB solutions in the AISC 360-16 and AS4100:2020 codes overestimate the buckling loads of cellular beams within elastic limits, particularly at shorter span lengths. The LDB solutions in the literature and the Eurocode 3 LTB solution, on the other hand, provided conservative buckling moment estimates along the entire range of elastic buckling.

• Korea Trade Review
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• v.46 no.6
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• pp.127-142
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• 2021

The Pohang Youngilman Port is the only international trade port in the Daegu-Gyeongbuk region, but its cargo throughput has been stagnated since its opening. Finding out ways to revitalize the port has been a big issue in the region, taking its potential business effects on the surrounding areas into consideration. This study, therefore, aimed to critically evaluate the government policies and empirically analyze business environments of the Pohang Youngilman Port as a fundamental to reach solutions for its revitalization. The policy evaluation showed that there are discrepancies in viewing contexts, implementations and mechanisms of the port at each government level, which resulted in implementing various but inconsistent solutions. Also, the interview results were analyzed to point out the fundamental problems, such as limited cargo volume due to weak hinterland development, lack of shuttle shipping between Busan New Port and Pohang Youngilman Port, and lack of large shippers to diverse the shipping network. This study has academic and managerial implications in suggesting measures for facilitation of the Pohang Youngilman Port by amalgamating various viewpoints of governments and stakeholders, which can be used for policy development as well as practical solutions for the port.

• Journal of the Korean Society for Heat Treatment
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• v.37 no.5
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• pp.221-227
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• 2024

The damping capacities in the strain-amplitude dependent and strain-amplitude independent regions were comparatively investigated for pure Mg and Mg-X%Al solid solutions (X : 1, 2 at%) to clarify the role of Al solute in the damping properties of Mg-Al binary solid solution. In order to rule out the effect of grain size on damping capacity, grain sizes of the samples were adjusted to an almost similar level by changing the heat-treatment or solution treatment times at 683 K (12 h, 24 h and 32 h for pure Mg, Mg-1%Al and Mg-2%Al alloys, respectively). The damping capacities of the heat-treated pure Mg and Mg-X%Al solid solutions exhibited a decreasing tendency with an increase in Al concentration both in the strain-amplitude dependent and strain-amplitude independent regions. The observed damping trends depending on strain-amplitude were analyzed and discussed in association with decreasing length between weak pinning points (Al solutes) in Granato-Lücke model.

• Bulletin of the Korean Chemical Society
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• v.31 no.6
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• pp.1561-1567
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• 2010

In this study, we have developed a new detection method using Si field effect transistor (FET)-type biosensors, which enables the direct monitoring of antigen-antibody binding within very high-ionic-strength solutions such as 1$\times$PBS and human serum. In the new method, as no additional dilution or desalting processes are required, the FET-type biosensors can be more suitable for ultrasensitive and real-time analysis of raw sample solutions. The new detection scheme is based on the observation that the strength of antigen-antibody-specific binding is significantly influenced by the ionic strength of the reaction solutions. For a prostate specific antigen (PSA), in some conditions, the binding reaction between PSA and anti-PSA in a low-ionic strength reaction solution such as 10 ${\mu}M$ phosphate buffer is weak (reversible), while that in high-ionic strength reaction solutions such as 1$\times$PBS or human serum is strong.

• The KIPS Transactions:PartB
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• v.11B no.7 s.96
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• pp.841-848
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• 2004

Evolutionary a1gorithms are well-suited for multi-objective optimization problems involving several, often conflicting objectives. Pareto-based evolutionary algorithms, in particular, have shown better performance than other multi-objective evolutionary algorithms in comparison. However, generalized evolutionary multi-objective optimization algorithms have a weak point, in which the distribution of solutions are not uni-formly distributed onto Pareto optimal front. In this paper, we propose an evolutionary a1gorithm for multi-objective optimization which uses seed individuals in order to overcome weakness of algorithms Published. Seed individual means a solution which is not located in the crowded region on Pareto front. And the idea of our algorithm uses seed individuals for reproducing individuals for next generation. Thus, proposed a1go-rithm takes advantage of local searching effect because new individuals are produced near the seed individual with high probability, and is able to produce comparatively uniform distributed pareto optimal solutions. Simulation results on five testbed problems show that the proposed algo-rithm could produce uniform distributed solutions onto pareto optimal front, and is able to show better convergence compared to NSGA-II on all testbed problems except multi-modal problem.