• Kyungpook Mathematical Journal
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• v.64 no.1
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• pp.133-159
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• 2024

In a previous work we studied generalized Stirling numbers of the second kind S^{(a₂,b₂,p₂)}_a1,b1 (p₁, k), where a₁, a₂, b₁, b₂ are given complex numbers, a₁, a₂ ≠ 0, and p₁, p₂ are non-negative integers given. In this work we use these generalized Stirling numbers to define Bernoulli polynomials in two variables B_p1,p2 (x₁, x₂), and Euler polynomials in two variables E_p1p2 (x₁, x₂). By using results for S^{(1,x₂,p₂)}_1,x1 (p₁, k), we obtain generalizations, to the bivariate case, of some well-known properties from the standard case, as addition formulas, difference equations and sums of powers. We obtain some identities for bivariate Bernoulli and Euler polynomials, and some generalizations, to the bivariate case, of several known identities for Bernoulli and Euler numbers and polynomials of the standard case.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.3
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• pp.263-276
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• 2015

Purpose: The current study aimed to evaluate the reliability for the combined refractive power when a spherical lens and a cylindrical lens were overlapped in a trial frame. Methods: The refractive powers, central thickness and peripheral thickness of spherical trial lenses and cylindrical lenses with negative power were measured. The combined refractive power of the spherical and cylindrical lenses was measured by auto lens meter. Measurement was repeated by changing the insertion order, and their results were further compared with the calculated combined refractive power. Results: There was no correlation between the variation of central and peripheral thickness in trial lenses and that of the lens power. Among 79 trial lenses, 3 trial lenses wasn't met the international standard. The refractive power calculated by Gullstrand's formula that could compensate vertex distance had smaller difference with the estimated power when compared with that calculated by thin lens formula however, it was significantly different from the estimated power. The refractive powers were generally apparent regardless of the insertion order of a spherical lens and a cylindrical lens: thin lens formula > actual measurements > Gullstrand's formula. The error was only found in cylindrical power calculated by Gullstrand's formula when inserted a spherical lens inside and a cylindrical lens outside however, the error was found in both of cylindrical and spherical powers calculated by Gullstrand's formula when inserted as a opposite order. By comparing actual measurements of equivalent spherical power, the accuracy was higher and the possibility of over-correction was lower when inserted a spherical lens inside and a cylindrical lens outside. Conclusions: From the results, those were revealed that the combined refractive power is influenced by the factors other than the vertex distance and the refractive power varies in accordance with the insertion order of a spherical lens and a cylindrical lens. Thus, it can be suggested that the establishment of standard for these is neccesaty.

• Research in Community and Public Health Nursing
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• v.13 no.1
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• pp.171-181
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• 2002

Purpose: To provide the basic data for nursing intervention to improve the psychosocial adaptation of unemployed homeless by examining the degree of self-esteem, depression. and hope, and the relation of these variables. Method: The subjects were a volunteer sample of 218 unemployed homeless residing at 2 shelters in Seoul and Suwon, Korea. The instruments for this study were Rosenberg's self-esteem scale, Beck's depression inventory, and Miller and Powers's hope scale. Using the SPSS program, the data were analysed by frequency, percentage, t-test, ANOVA, Duncan test and Pearson Correlation Coefficient. Result: 1) The degree of self-esteem is, on average, 23.72 points, depression is 24.41 points, and hope is 124.72 points. 2) The degree of self-esteem in the general characteristics of the subjects showed a significant difference by age, marital status, and contact with family. 3) The degree of depression in the general characteristics of the subjects showed a significant difference by age, marital status, and contact with family. 4) The degree of hope in the general characteristics of the subjects showed a significant difference by contact with family. 5) There was a significant positive correlation between the variables of self-esteem and hope, while there was a significant negative correlation between the variables of self-esteem and depression, and hope and depression. Conclusion: 1) The study identifies psychological characteristics of the homeless. 2) It is required not only to develop nursing intervention programs to improve the degree of self-esteem and hope, and alleviate depression but also to testify the effect of the program. 3) It is needed to develop nursing intervention programs to prevent chronic homelessness.

• The Korean Journal of Physiology and Pharmacology
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• v.9 no.1
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• pp.17-22
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• 2005

We examined whether the abnormal EEG state by NMDA receptor blocker MK-801 can be reversed by typical and atypical antipsychotics differentially by comparing their spectral profiles after drug treatment in rats. The spectral profiles produced by typical antipsychotics chlorpromazine (5 mg/kg, i.p.) and haloperidol (0.5 mg/kg, i.p.) were differ from that by atypical antipsychotic clozapine (5 mg/kg, i.p.) in the rats treated with or without MK-801 treatment (0.2 mg/kg, i.p.) which produce behavioral abnormalities like hyperlocomotion and stereotypy. The dissimilarity between the states produced by antipsychotics and the control state was examined with the distance of the location of the canonical variables calculated by stepwise discriminant analysis with the relative band powers as input variables. Although clozapine produced more different state from normal state than typical antipsychotics, clozapine could reverse the abnormal schizophrenic state induced by MK-801 to the state closer to the normal state than the typical antipsychotics. The results suggest that atypical anesthetic can reverse the abnormal schizophrenic state with negative symptom to the normal state better than typical antipsychotic. The results indicate that the multivariate discriminant analysis using the spectral parameters can help differentiate the antipsychotics with different actions.

• Journal for History of Mathematics
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• v.24 no.3
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• pp.109-143
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• 2011

Augustus De Morgan became to be deeply interested in the education of pure mathematics since he came to teach in UCL because of the specific nature of natural philosophy lectures, the academical knowledge and reasoning powers of the students, and the negative attitudes of London society on mathematics. During his long tenure, he really tried his best to make his students understand the important concepts and the principles of pure mathematics, and logically explain the processes of inducing and proving the laws of pure mathematics. When he could not stay as a mere researcher, he had to concern himself with and pay attention to the problems of educating students. And then his teaching style was constructed in a specific way by the various attitudes about mathematics, the boundary relationship between the adjacent academical branches, and the social and systematic nature of UCL.

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.3
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• pp.348-363
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• 2013

The use of I-Core sandwich panel has increased in cruise ship deck structure since it can provide similar bending strength with conventional stiffened plate while keeping lighter weight and lower web height. However, due to its thin plate thickness, i.e. about 4~6 mm at most, it is assembled by high power $CO_2$ laser welding to minimize the welding deformation. This research proposes a volumetric heat source model for T-joint of the I-Core sandwich panel and a method to use shell element model for a thermal elasto-plastic analysis to predict welding deformation. This paper, Part I, focuses on the heat source model. A circular cone type heat source model is newly suggested in heat transfer analysis to realize similar melting zone with that observed in experiment. An additional suggestion is made to consider negative defocus, which is commonly applied in T-joint laser welding since it can provide deeper penetration than zero defocus. The proposed heat source is also verified through 3D thermal elasto-plastic analysis to compare welding deformation with experimental results. A parametric study for different welding speeds, defocus values, and welding powers is performed to investigate the effect on the melting zone and welding deformation. In Part II, focuses on the proposed method to employ shell element model to predict welding deformation in thermal elasto-plastic analysis instead of solid element model.

• International Journal of Advanced Culture Technology
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• v.7 no.4
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• pp.63-68
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• 2019

Recently, the United States and China have declared a 25% retaliatory tariff for the partner country products of 50 billion dollar scale. "Trade war" is getting full swing. Such conflicts between economic powers may spread to Japan like the domino phenomenon following the EU (European Union) and become bigger in the global trade war. As a result, Korea has an economic system with a high degree of external dependence, and there is an expert's analysis that it will become the largest victim of the global trade war. If the WTO Dispute Settlement Authority approves this US 301 retaliation measure in the same way as the past case (US-EU hormone-treated beef imports), the United States will not import any Chinese imported products Chinese products) can be imposed. If the US launches a special 301 or super 301, which is stronger than the regular 301, then China is very likely to enforce US retaliation against it, and the trade war between the two countries could become a reality. This phenomenon is likely to have a negative impact on Korean companies. In particular, Korea, which is highly reliant on intermediate goods exports to China, is expected to suffer a great deal of damage. Therefore, Korea needs flexible response at home and abroad, it is necessary to enhance the autonomy of companies and protect export industries. Adjusting corporate tax rate as well as domestic industry height will be one way. The long-term (21 months) trade war between the United States and China has resulted in economic uncertainty. The resulting damage must be compensated. It is necessary to prepare the compensation through the economic council between countries. In the future, the punitive damage compensation system should be introduced.

• Analyses & Alternatives
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• v.3 no.2
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• pp.59-85
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• 2019

The Hong Kong's Anti-Ordinance Amendment Movement is the most serious radical social movement since the 1997 return, which has served as the promotion of the 2014 Occupy Central Movement and broken through the violence baseline. The movement came from a criminal case committed in Taiwan,which gave a good reason and motivation for the HK government to amend the Fugitive Offenders Ordinance. The HK government has responded to the protests by strictly limiting the legal scope and transfer procedure, even giving up the legislative motion. But the protests still say no and develop into the constantly violent activities. Many of the protests have committed the crimes in HK laws,part of whom have been arrested,prosecuted and under judicially judged. It is necessary for the offenders to be punished to protect the authority of rule of law in HK. Two different paths for HK have fought against each other since the 1997 return: one is the "democratic-welfare" path taken by the Pan-Democratic Camp, the other is the "Legal-development" path taken by the Pan-Establishment Camp. The second path shares some nuclear characteristics of the so-called The China Model mainly shaped from the 40-years Reforms and Openness. However, the HK people can't understand the China Model very well and show great fear and distrust on the judicial system of Mainland China. The foreign powers such as US and UK have illegally interfered the HK issues which are deemed to be the domestic affairs of China. The so-called Sino-UK Joint Declaration can't serve as the legal basis for the interference. Taiwan, as a part of China, also plays a negative role in this movement for its electoral and political interest. Up to now, the movement has gone down and the HK government has the legal capacity to solve the problems under the supports from the central government and the HK people. The HK people love its rule of law and order under the constitutional framework of One Country Two System. After the movement,One Country Two Systems will be go on, and the integrated development under the policies of the central government will be the main stream. However, the relevant problems exposed by this movement muse be checked and solved legally and strictly,especially concerning the social inequality and youth development.

• Current Optics and Photonics
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• v.7 no.6
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• pp.738-744
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• 2023

Graphene-based saturable absorbers (SAs) are widely used as laser mode-lockers at various laser oscillators. In particular, transmission-type graphene-SAs with ultrabroad spectral coverage are typically manufactured on transparent substrates with low nonlinearity to minimize the effects on the oscillators. Here, we developed two types of transmitting graphene SAs based on CaF₂ and ZnSe. Using the graphene-SA based on CaF₂, a passively mode-locked mid-infrared Cr:ZnS laser delivers relatively long 540 fs pulses with a maximum output power of up to 760 mW. In the negative net cavity dispersion regime, the pulse width was not reduced further by inhomogeneous group delay dispersion (GDD) compensation. In the same laser cavity, we replaced only the graphene-SA based on CaF₂ with the SA based on ZnSe. Due to the additional self-phase modulation effect induced by the ZnSe substrate with high nonlinearity, the stably mode-locked Cr:ZnS laser produced Fourier transform-limited ~130 fs near 2,340 nm. In the stable single-pulse operation regime, average output powers up to 635 mW at 234 MHz repetition rates were achieved. To our knowledge, this is the first attempt to achieve shorter pulse widths from a polycrystalline Cr:ZnS laser by utilizing the graphene deposited on the substrate with high nonlinearity.

• The Journal of the Convergence on Culture Technology
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• v.10 no.1
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• pp.193-203
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• 2024

In a situation where news usage through YouTube is rapidly increasing, this study investigated which attributes of issues news producers prominently report on based on the two-stage agenda setting theory to empirically investigate the influence of various news producers on YouTube. Through the research results, we confirmed that broadcasters have the influence to set the agenda and form public opinion on YouTube, and discovered the possibility of a two-stage agenda setting effect occurring in the YouTube environment. We criticized whether news producers abuse emotional words due to their partisanship when reporting political issues, and discussed that an emotional approach to political issues can have a negative impact on news users' perception of reality.