• 디지털융복합연구
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• 제19권5호
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• pp.241-247
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• 2021

본 연구는 1990년도부터 2019년까지 거래소에 상장된 기업들을 대상으로 발생액 추정모형의 설명력 변화를 분석하였다. 기존의 발생액 추정모형에 사용된 재무적 변수들이 특성이 시간이 지남에 따라 변화하거나, 전체 발생액 중에서 재량적 발생액의 비중이 변화하면 모형의 설명력에도 변화가 있을 것으로 기대하고 이를 가설화하여 분석하였다. 회귀 분석결과 수정 Jones 모형(1995)은 시간의 경과에 따라 그 설명력이 점차 낮아짐을 발견하였다. 이는 발생액 자체의 증가와 모형에 포함된 변수들의 분포가 변화함에 기인하는 것으로 추정된다. 본 연구의 시계열적 분석 결과는 이익조정 연구 등 학술적인 면이나 회계 정보를 이용하는 이용자에게 중요한 시사점을 제공할 것으로 기대된다.

• 응용통계연구
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• 제14권1호
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• pp.25-37
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• 2001

세 처리, 세 기간을 갖는 3$\times$3 교차실험에서 c($\geq$3)개의 범주를 가진 자료의 분석에 사용될 수 있는 주변확률모형을 제안한다. 이 모형은 Kenward and Jones(1991)의 결합확률 모형의 대조물 (counterpart)로 사용될 수 있고 2항 변수를 갖는 3$\times$3 교차실험에서 처리 효과를 분석하기 위한 Balagtas et al(1995)의 일변량주변로지트모형의 일반화이다. 세 종류의 링크변화를 사용하여 주변확률모형방정식의 구성된다. 링크변환행렬과 모형행렬을 구성하는 방법이 주어지고, 모수의 추정이 논의된다. 제안된 모형을 Kenward and Jones 자료의 분석에 응용한다.

• 유통과학연구
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• 제17권12호
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• pp.5-12
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• 2019

Purpose - In this paper, we examine the effect of accrual earnings management and real earnings management on the corporate value of retail corporations. Research design, data, and Methodology - The sample cover firms whose settlement is December among retail companies listed on the Korea Stock Exchange's securities market and KOSDAQ market from 2001 to 2016. Of these, the targets were companies with operating profit and equity capital of zero or higher and with sales data. The secondary data was collected through KIS-VALUE data base. The Jones model and the modified Jones model were used for the calculating the accrual-based earnings management and the real earnings management. Result - According to the empirical results, the relationship between accrual earnings management, real earnings management and firm value is positively significant in the retail industry as in manufacturing industry. These results are also significant when controlling the size, profitability, investment, debt ratio, dividend, and growth potential of a company. Conclusions - The characteristics of the distribution business can be identified and the influence of the various kinds of earnings management, which is being researched around the manufacturing industry, can be studied in the distribution industry to give practical implications to investors.

• Communications for Statistical Applications and Methods
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• 제27권3호
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• pp.301-311
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• 2020

Schwarz's Bayesian information criterion (BIC) is one of the most popular criteria for model selection, that was derived under the assumption of independent and identical distribution. For correlated data in longitudinal studies, Jones (Statistics in Medicine, 30, 3050-3056, 2011) modified the BIC to select the best linear mixed effects model based on the effective sample size where the number of parameters in covariance structure was not considered. In this paper, we propose an extended Jones' modified BIC by considering covariance parameters. We conducted simulation studies under a variety of parameter configurations for linear mixed effects models. Our simulation study indicates that our proposed BIC performs better in model selection than Schwarz's BIC and Jones' modified BIC do in most scenarios. We also illustrate an example of smoking data using a longitudinal cohort of cancer patients.

• Journal of Microbiology and Biotechnology
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• 제31권8호
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• pp.1115-1122
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• 2021

Rotavirus (RV), as the main cause of diarrhea in children under 5 years, contributes to various childhood diseases. Valeriana jatamansi Jones is a traditional Chinese herb and possesses antiviral effects. In this study we investigated the potential mechanisms of V. jatamansi Jones in RV-induced diarrhea. MTT assay was performed to evaluate cell proliferation and the diarrhea mice model was constructed using SA11 infection. Mice were administered V. jatamansi Jones and ribavirin. Diarrhea score was used to evaluate the treatment effect. The enzyme-linked immunosorbent assay was performed to detect the level of cytokines. Western blot and quantitative reverse transcription-PCR were used to determine protein and mRNA levels, respectively. Hematoxylin-eosin staining was applied to detect the pathological change of the small intestine. TdT-mediated dUTP nick-end labeling was conducted to determine the apoptosis rate. The results showed V. jatamansi Jones promoted MA104 proliferation. V. jatamansi Jones downregulated phosphatidylinositol 3-kinase (PI3K) and protein kinase B (AKT) in protein level, which was consistent with the immunohistochemistry results. Moreover, V. jatamansi Jones combined with ribavirin regulated interleukin-1β (IL-1β), interferon γ, IL-6, tumor necrosis factor α, and IL-10, and suppressed secretory immunoglobulin A secretion to remove viruses and inhibit dehydration. V. jatamansi Jones + ribavirin facilitated the apoptosis of small intestine cells. In conclusion, V. jatamansi Jones may inhibit RV-induced diarrhea through PI3K/AKT signaling pathway, and could therefore be a potential therapy for diarrhea.

• 한국전자통신학회논문지
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• 제14권1호
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• pp.147-154
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• 2019

이 연구에서는 분자들이 노즐과 터빈내부에서 운동하는 거동을 모사하기 위해 분자동력학 시뮬레이션 시스템의 모델을 설계하고 개발하였다. Lennard-Jones Potential 모델을 이용하여 분자들간에 상호 작용을 계산하고, Verlet 알고리듬을 뉴턴의 운동 방정식을 적산하기 위한 수치해석 방법으로 사용하였다. Lennard-Jones Potential 함수를 계산하기 위해, 분자 개수 N에 대해 $O(N^2)$ 계산량을 cutoff $r_c$를 이용하여 O(N)으로 줄여서 계산하여 CPU 시간을 절약할 수 있도록 구현하였다.

• 유통과학연구
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• 제17권4호
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• pp.5-16
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• 2019

Purpose - This study examines whether price cartel firms perform downward earnings management to avoid or minimize penalty surcharges levied by the Korea Fair Trade Commission and analyzes such earnings management in distribution industry. Research design, data, and methodology - We use 247 firms from 64 price cartel cases in the period of 2011-2016, and collect data from 3 years before to 3 years after the start of price cartel. Earnings management is measured by discretionary accruals. Three discretionary accrual estimation models are employed; modified Jones model, ROA adjusted modified Jones model and CFO-adjusted modified Jones model. For pre- and post-cartel periods, one year, two year, and three year windows are used. Additional empirical analyses are performed for distribution industry sub-sample of 25 cartel firms. Result - The regression results show that cartel firms' discretionary accruals are significantly lower in the period after the start of price cartel than before. And discretionary accruals are lower in cartel firms than in non-cartel firms during the cartel period. Cartel firms in distribution industry also show the earnings management similar to those in other industries. Conclusions - These two findings lead to the conjecture that managers of cartel firms manage their earnings downward. This behavior is indistinguishable between firms in distribution industry and other industries.

• Structural Engineering and Mechanics
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• 제89권2호
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• pp.135-153
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• 2024

In this study, the impact response of a nanobeam with a moving nanoparticle is investigated. Timoshenko beam theory is used to model the nanobeam behavior and nonlocal elasticity theory is used to consider the effects of small dimensions. The interaction between the nanoparticle and nanobeam has been described using Lennard-Jones potential theory and the equations are discretized by the radial basis meshless method and a mathematical model is presented for the nanobeam-nanoparticle system. Validation of the proposed model is achieved by comparing the obtained natural frequencies with reference values, demonstrating good agreement. Dimensionless frequency analysis reveals a decrease with increasing nonlocal parameter, pointing out a toughening effect in nanobeam. The dynamic response of the nanobeam and nanoparticle is obtained by time integration of equations of motion using Newmark and Wilson-𝜃 methods. A comparative analysis of the two methods is conducted to determine the most suitable approach for this study. As a distinctive aspect in this study, the analysis incorporates the deformation of the nanobeam resulting from the nanoparticle-nanobeam interaction when calculating the Lennard-Jones force in the nanobeam-nanoparticle system. The numerical findings explore the impact of various factors, including the nonlocal parameter, initial velocity, nanoparticle mass, and boundary conditions.

• 한국분무공학회지
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• 제13권1호
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• pp.34-41
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• 2008

Molecular dynamic simulations have been carried out to study the effect of the nano-structure substrate and its temperature on cluster laminating. The interaction between substrate molecules and liquid molecules was modeled in the molecular scale and simulated by the molecular dynamics method in order to understand behaviors of the liquid cluster on nano-structure substrate. In the present model, the Lennard-Jones potential is applied to mono-atomic molecules of argon as liquid and platinum as nano-structure substrate to perform simulations of molecular dynamics. The effect of wettability on a substrate was investigated for the various beta of Lennard-Jones potential. The behavior of the liquid cluster and nano-structure substrate depends on interface wettability and function of molecules force, such as attraction and repulsion, in the collision progress. Furthermore, nano-structure substrate temperature and beta of Lennard-Jones potential have effect on the accumulation ratio. These results of simulation will be the foundation of coating application technology for micro fabrication manufacturing.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 학술대회
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• pp.208-214
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• 2008

The equilibrium molecular-dynamic simulations have been performed to estimate the properties of the three kinds of fluids (the Lennard-Jones fluid, water and aqueous sodium-chloride solution) confined between two plates that are separated by 1.086 nm; included in the equilibrium properties are the density distribution and the static structure, and the diffusivity in the dynamic property. Three kinds of fluids considered in this study are. The water molecules are modeled by using the SPC/E model and the ions by the charged Lennard-Jones particle model. To treat the water molecules, we combined the quaternion coordinates with Euler angles. We also proposed a plausible algorithm to assign the initial position and direction of molecules. The influence of polarization of water molecules as well as the presence of ions in the solution on the properties will be addressed in this study. In addition, we performed the non-equilibrium molecular-dynamic simulation to compute the flow velocity for the case with the gravitational force acting on molecules.