• Journal of the Korean Mathematical Society
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• v.57 no.2
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• pp.429-450
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• 2020

We prove that wave operators for Schrödinger operators with multi-center local point interactions are scaling limits of the ones for Schrödinger operators with regular potentials. We simultaneously present a proof of the corresponding well known result for the resolvent which substantially simplifies the one by Albeverio et al.

• Journal of Computing Science and Engineering
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• v.3 no.4
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• pp.218-237
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• 2009

Interactions are intrinsic part of what we do. We interact when we work, when we learn, when we visit a doctor, and when we play. With the advent of information and communications technology we can collect rich data (video, audio, and various transcripts including text chat) about such interactions. This opens an opportunity to monitor the dynamics of interactions and to get deeper insights of how they unfold and deliver this information to the interacting parties. This paper presents the design of a technology for visualising information about the dynamics of unfolding of interactions and presenting it in an ambient display on mobile devices. The purpose of this technology is the delivery of such information to the point of decision making.

• East Asian mathematical journal
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• v.34 no.3
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• pp.317-330
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• 2018

We develop a mathematical model for the obesity dynamics to investigate the long term obesity trend with the consideration of psychological and social factors due to the increasing prevalence of obesity around the world. Many mathematical models for obesity dynamics adopted the modeling idea of infectious disease and treated overweight and obese people infectious and spreading obesity to normal weight. However, this modeling idea is not proper in obesity modeling because obesity is not an infectious disease. In fact, weight gain and loss are related to social interactions among different weight groups not only in the direction from overweight/obese to normal weight but also the other way around. Thus, we consider these aspects in our model and implement personal weight gain feature, a psychological factor such as body image dissatisfaction, and social interactions such as positive support on weight loss and negative criticism on weight status from various weight groups. We show that the equilibrium point with no normal weight population will be unstable and that an equilibrium point with positive normal weight population should have all other components positive. We conduct computer simulations on Korean demography data with our model and demonstrate the long term obesity trend of Korean male as an example of the use of our model.

• Elastomers and Composites
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• v.41 no.2
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• pp.116-124
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• 2006

Cloud-point data to $160^{\circ}C$ and 1,000 bar are presented with poly(ethylene-co-15.3 mole% octene) copolymers ($PEO_{15}$) in pure 1-octene and mixtures of ethylene - 1-octene. The cloud-point curves for $PEO_{15}$ - ethylene - 1-octene mixture dramatically increase in pressure to as high as 1,000 bar with an increasing ethylene concentration. At ethylene concentrations less than 18 wt%, the ternary mixture has bubble- and cloud-point curves. As the ethylene concentration of the ternary mixture increases, the bubble-point curve and the single-phase region reduce. The reduction in the single phase region with increasing ethylene concentrations is the result of reduced dispersion interactions between $PEO_{15}$ and the mixed solvent. The single-phase region decreases with increasing temperatures when ethylene concentrations are lower than 36 wt%, whereas the single-phase region increases with temperatures at ethylene concentrations greater than 50 wt%. At ethylene concentrations greater than 50 wt% the effect of the polar interactions of the mixed solvent, which is unfavorable to dissolve PEO, is greater than the effect of the density of the mixed solvent. Therefore, the cloud-point pressures increase with a decreasing temperature. However, at ethylene concentrations less than 50 wt%, the cloud-point pressures decrease with temperature, because the effect of the polar interactions is less than the density effect.

• Smart Structures and Systems
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• v.33 no.4
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• pp.281-290
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• 2024

This work investigates the mechanical energy harvesting from smart and adaptive devices using magnetic interactions. The energy harvester is built from an elastic beam connected to an electric circuit by a magnetostrictive material that promotes energy transduction. Besides, magnetic interactions define the system stability characterizing multistable configurations. The adaptiveness is provided by magnets that can change their position with respect to the beam, changing the system configuration. A mathematical model is proposed considering a novel model to describe magnetic interactions based on the single-point magnet dipole method, but employing multiple points to represent the magnetic dipole, which is more effective to match experimental data. The adaptive behavior allows one to alter the system stability and therefore, its dynamical response. A nonlinear dynamics analysis is performed showing the possibilities to enhance energy harvesting capacity from the magnet position change. The strategy is to perform a system dynamical characterization and afterward, alter the energetic barrier according to the environmental energy sources. Results show interesting conditions where energy harvesting capacity is dramatically increased by changing the system characteristics.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09b
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• pp.122-130
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• 2010

In recent days, the foundations of huge structures in general and mega foundations of grand bridges in particular are required in geotechnical engineering. However, previous design method based on virtual fixed point theory cannot adequately predict Pile-Bent structure‘s physical behavior. Therefore, this paper describes a new analysis and design of Pile-Bent structure for grand bridges. A detailed analysis was performed for column-pile interactions using FB-Pier program and Midas program. As a result, the behavior of a column-pile is estimated and highlighted. Moreover, based on this study, it is found that the minimum reinforcement ratio(=0.4%) is applicable for plastic behavior of columns.

• Journal of the Korean Home Economics Association
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• v.42 no.6
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• pp.123-136
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• 2004

The purposes of this study were to investigate the qualities of infant day-care centers and the caregivers' interactions with infants. Forty-six day-care centers from Seoul, Daejeon, and Daegu were enrolled in this study. Two kinds of methods were used for data collection; one was the Assessment Scale for Infant/Toddler Care Center developed by Choi and the other was the Qualitative Rating Scale for Caregiver used in the NICHD Early Child Care Project. Frequency, percentile, Crollbach's, one-way ANOVA, and Pearson's correlation were calculated for data analysis. Qualities on 5 factors of infant day-care centers were ranged from 3.44∼4.35, the highest with health managing and the lowest with support system in the Likert 5-point scales. Sensitivity, developmental stimulation and positive regard to child, which are the caregiver's positive interactions with infants were rated minimally or usually characteristic. In addition, intrusiveness, detachment, negative regard to child and flatness, which are negative interactions with infants were rated never or minimally characteristic. Finally, some suggestions for good quality and facilitation of infant care were made.

• Korean Journal of Biological Psychiatry
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• v.7 no.1
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• pp.3-13
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• 2000

There is nothing that is harmless ; the dose alone decides that something is no poison(Paracelsus, 1493-1541). So, in a point of view to maximize the therapeutic efficacy of drug therapy in a way that minimize the drug toxicity, the knowledges of the drug-ineractions as well as the pharmacokinetic and pharmacodynamic principles of every therapeutic drug used in the medical clinic cannot be emphasized too much. Many drug interactions can be predicted if the pharmacokinetic properties, pharmacodynamic mechanisms of action of the interacting drugs are known, and most adverse interactions can be avoided. In this paper, the clinical importance, classification, and general principles of clinical drug-interactions are presentated with a few explanatory examples.

• Elastomers and Composites
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• v.38 no.1
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• pp.51-56
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• 2003

Cloud-point and bubble-point data to $170^{\circ}C$ and 50 bar are presented for four different solvents, normal pentane. n-hexane, n-heptane, and n-octane with poly(ethylene-co-42 wt% octene) ($PEO_{42}$) copolymer. The pressure-concentration isotherms measured for $PEO_{42}$ - normal pentane have maximums at around 5 wt% of the copolymer concentrations in the solution. $PEO_{42}$- normal pentane system exhibits LCST-type phase behavior at temperatures greater than $130^{\circ}C$. Below $120^{\circ}C$, bubble-point type transitions are observed. However, the binary mixtures for $PEO_{42}$ in n-hexane, n-heptane, and n-octane have only bubble-point type transitions at the pressure-temperature region investigated in this study. The single-phase region of PEO - alkane mixtures increases with the molecular size of alkane solvent due to the increasing dispersion interactions between PEO and the alkane.

• Journal of the Korean Chemical Society
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• v.51 no.4
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• pp.375-386
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• 2007

The purpose of this study is to investigate the aspects of verbal interactions of teacher?small group students by categorizing those interactions which affect students' thinking thus to improve teacher's interaction. First, verbal interactions of teacher-small group students were divided into two categories ?Behaviors related to problem-solving, and Others. Behaviors related to problem-solving were also classified into two elements?Receiving opinion based on the students' thinking process, and Giving help based on the teacher's thinking process. Receiving opinion consists of agreement, question, correction, objection while giving help consists of information, hint, question, summary, and ask & answer. Most of teacher-small group students' interactions were in the form of teacher's questions and students' answers, and teacher's questions tended to require simple answers rather than answers from deep thought. In addition, there was a tendency that the teacher focused more on her own thinking process than students' and that she interacted with only a couple of students who gave correct answers. As a result, even after teacher's scaffolding, many students were often unable to understand the particular contents. However, through the interactions, the teacher made students to have confidence by restating their opinions and agreeing or praising them. She also created an atmosphere where students can give their opinions freely. From the observation of interactions, we can find that students' thinking process is affected by the characteristics of teacher's interactions such as expression of agreement and encouragement, hint giving rise to thought, interactions based on the students' thinking process, permission of students' activities and questions, allowing time for students' thought, and correction of wrong opinions. At this point, educational implications of teacher-small group students' interactions were drawn.