• Bulletin of the Korean Mathematical Society
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• v.54 no.6
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• pp.2165-2182
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• 2017

Let G be a group and $\mathbb{C}$ the field of complex numbers. Suppose ${\sigma}:G{\rightarrow}G$ is an endomorphism satisfying ${{\sigma}}({{\sigma}}(x))=x$ for all x in G. In this paper, we first determine the central solution, f : G or $G{\times}G{\rightarrow}\mathbb{C}$, of the functional equation $f(xy)+f({\sigma}(y)x)=2f(x)+2f(y)$ for all $x,y{\in}G$, which is a variant of the quadratic functional equation. Using the central solution of this functional equation, we determine the general solution of the functional equation f(pr, qs) + f(sp, rq) = 2f(p, q) + 2f(r, s) for all $p,q,r,s{\in}G$, which is a variant of the equation f(pr, qs) + f(ps, qr) = 2f(p, q) + 2f(r, s) studied by Chung, Kannappan, Ng and Sahoo in [3] (see also [16]). Finally, we determine the solutions of this equation on the free groups generated by one element, the cyclic groups of order m, the symmetric groups of order m, and the dihedral groups of order 2m for $m{\geq}2$.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.9
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• pp.867-873
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• 2008

Model based virtual Flight Control System construction is essential for Fly-by-Wire Flight Control System verification & validation(V&V) of concurrent engineering base. We researched the concept of dual-architecture system for virtual system construction, and analyzed Flight Control System that is applied to high altitude long endurance(HAE) UAS. Finally, we constructed the model based virtual Flight Control System with system analysis and achieved system verification about flight critical failure modes. Analysis target is RQ-4A.

• KSBB Journal
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• v.29 no.4
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• pp.263-270
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• 2014

This study reports significant improvement of atopic dermatitis condition as a result of experiment using Xanthium strumarium L. extract (XS-E) at the dorsal skin of induced atopic dermatitis Nc/Nga mice. Skin clinical score has decreased ($2.75{\pm}0.85$, *p<0.05), showing visible change of skin condition. IgE (***p<0.001) and IgG1 ($2522.00{\pm}32.80$, ***p<0.001) in plasma also decreased significantly. mRNA (gene expression) level increased ($RQ=2.75{\pm}0.10$, ***p<0.001) within skin tissue of CD4+CD25+Foxp3+ Treg cell that's activated by XS-E dosage, thereby discovering that there is an effect of suppressing proliferation and viability of Th2 cell, eosinophils, mast cell and inflammatory cell. Upon examining cells permeated with H&E and toluidine blue staining technique, thickness of epidermis and mast cell's permeation decreased, and the result of examining the distribution of CCR 3+ eosinophils within ALN showed that it's level fell down to that of wild type (normal group, NC/Nga-WT). By such results, it is suggested that XS-E is highly effective on atopic dermatitis, and it is considered that continued quantitative research and case study of clinical research such as effect of cell number in individual tissues or change of total cell number are necessary.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.10
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• pp.275-281
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• 2020

This study aims to explore a new approach of relationship assessment by partially employing attitudinal commitment to measure the influence on perception of cooperation within the Vietnamese rice supply chains, which begins from commercial enterprises up to the retailers in the Vietnamese market. The quantitative research is first built around the measurement instruments for the constructs of relationship quality (RQ) and its dimensions; next, a questionnaire is designed; finally, we deal with sample issues and analyze the data to answer the research questions. The truncated sampling technique and Likert-scale survey is a suitable method for analyzing Vietnamese rice retailers and data collection. The preliminary test was conducted using SPSS Statistics; the main test was, then, carried out to evaluate the proposed model and test the hypotheses. Appropriately, the results point to a significant influence of attitudinal factors on trust and satisfaction. In addition, with the involvement of perceived trust and satisfaction, that combination showed the mediating effect between the attitudinal factors and the relationship quality. The ad-hoc analysis indicated the significant role of the two mediators. To be more specific, the high degree of trust and satisfaction has a positive impact on the formation of the relationship between participants in the sector.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.2
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• pp.264-270
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• 2006

In this paper we verified that the window based TCP performance of throughput can be improved by the traffic connection efficiency. and have studied the performance of traffic congestion control that is controlling transmission rate. In wireless network, the bidirectional node is run by estimating the usage rate of link of error control idle and the throughput is shown by transmitting segments. The throughput rate shows almost no delay due to the bidirectional traffic connection efficiency up to the allowable point as increasing the transport rate by the critical value, depending on the size of end-to-end node queue of the increase of transport rate. This paper reports the performance improvement as the number of feedback connection traffic congestion control increases because of the increase of the number of asynchronous transport TCP connections.

• Bulletin of the Korean Mathematical Society
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• v.56 no.5
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• pp.1187-1198
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• 2019

Let R be a domain with its field Q of quotients. An R-module M is said to be weak w-projective if $Ext^1_R(M,N)=0$ for all $N{\in}{\mathcal{P}}^{\dagger}_w$, where ${\mathcal{P}}^{\dagger}_w$ denotes the class of GV-torsionfree R-modules N with the property that $Ext^k_R(M,N)=0$ for all w-projective R-modules M and for all integers $k{\geq}1$. In this paper, we define a domain R to be w-Matlis if the weak w-projective dimension of the R-module Q is ${\leq}1$. To characterize w-Matlis domains, we introduce the concept of w-Matlis cotorsion modules and study some basic properties of w-Matlis modules. Using these concepts, we show that R is a w-Matlis domain if and only if $Ext^k_R(Q,D)=0$ for any ${\mathcal{P}}^{\dagger}_w$-divisible R-module D and any integer $k{\geq}1$, if and only if every ${\mathcal{P}}^{\dagger}_w$-divisible module is w-Matlis cotorsion, if and only if w.w-pdRQ/$R{\leq}1$.

• Journal of Auto-vehicle Safety Association
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• v.12 no.4
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• pp.31-38
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• 2020

This study is to develop the prediction model for the HIC15 in frontal vehicle crash tests. The 28 frontal impact test results of the MY2019 and MY2020 USNCAP are utilized. The metrics for evaluating the crash pulse severity such as moving average acceleration, Restraint Quotient (RQ) and ride-down efficiency are reviewed to find out whether the metrics can predict the HIC15. It is observed that the R² values based on the linear regression of all pairs between the existing metrics and the occupant injuries such as the HIC15, 3 ms chest g's and chest deflection are very low. In this study, using the vehicle crash pulses, the linear regression model for estimating the HIC15 is developed. The vehicle crash pulse is splitted seven 10 ms intervals in 70 ms after impact for extracting the average accelerations in each intervals. The prediction model can predict effectively not only the HIC15 but also the maximum head g's, chest deflection and 3 ms chest g's of 13 vehicles out of 28 vehicles.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.2
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• pp.115-120
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• 2021

In this study, composite transparent electrodes were fabricated either from a conductive polymer poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) or silver nanowire (AgNW). Three transparent electrodes such as PEDOT:PSS, PEDOT:PSS and AgNW mixture, and AgNW were fabricated. As for a transparent electrode, measured sheet resistance values were 89.6, 60.6 and 28.6 Ω/sq, and the transmittance values were 80.2, 82.0 and 83.8% while surface roughness (Rq) values were 4.1, 8.1, 20.4 nm for PEDOT:PSS, PEDOT:PSS and AgNW mixture, and AgNW, respectively. To verify the overall performance of these composite electrodes, we applied these electrodes to the top electrode of the solution-processed organic solar cells (OSCs). PEDOT:PSS provided the best performance with a fill factor (FF) of 51.2% and a photoconversion efficiency (PCE) of 2.2%, while traditional metal top electrode OSC provided FF of 60.5% and PCE of 3.1%.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.29 no.2
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• pp.36-46
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• 2021

The purpose of this study is to ensure safety by proactively identifying hazards that could be derived from changes in mission form and environment as the advanced aircraft such as F-35A stealth fighter, KC-330 Multi-role transport and tanker, RQ-4B high altitude unmanned reconnaissance aircraft, etc are introduced that the Republic of Korea Air Force(ROKAF) has never been operated so far. To this end, the safety management methods based on proactive and predictive approaches used in advanced countries(US Air Force, UK Royal Air Force, Royal Australian Air Force) operating aircraft types same or similar things being newly powered by the ROKAF were reviewed. In addition, the direction for improvement of the safety management methods operating in the ROKAF and the measures necessary for establishment of the new safety management techniques to be applied were suggested.

• Korea Trade Review
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• v.47 no.2
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• pp.89-101
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• 2022

International remittances play a crucial role in the economic management of each country, especially in developing countries. Its functions are diverse, including procurement of foreign currency, serving as a cushion for the balance of payments and foreign exchange reserves by reducing the adverse external shocks, driving economic growth, easing the gap between the rich and the poor, and maintaining macroeconomic stability. However, previous studies on remittances have mainly focused on macro-and micro-economic aspects to analyze the determinants. Therefore, this study attempts to identify the determinants of remittances in 122 countries over the past 25 years from macroeconomic and educational aspects as well as institutional qualities. In addition, given the fact that almost all of the world's top 10 recipient countries in terms of GDP and total remittance size are developing countries, developed and developing countries are separated and analyzed for comparison, assuming that there may be a difference between the two groups. Results show that the coefficients of developed and developing countries are different in four areas: Control of Corruption (CC), Rule of Law (RL), Voice and Accountability (VA), and Regulatory Quality (RQ) among the six institutional variables of interest in this study. These results implicate that even the same institutions and policies should be applied and implemented differently depending on the circumstances of each country. In addition, as suggested by the World Bank, policymakers in all countries should double their policy efforts to lower the costs of remittance and improve access to the financial system for immigrants or dispatched workers to ensure a steady inflow of remittances.