• 한국전기전자재료학회논문지
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• 제26권6호
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• pp.457-461
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• 2013

In this paper, a novel method based on geometrical optics is proposed to calculate the optical characteristics of an electric field driven liquid crystal (ELC) lens. For an optimally designed ELC lens, effective refractive index is calculated and then ray tracing is carried out using Huygens' principle. From the results, the intensity distribution at the optimum viewing distance (OVD) is obtained. To confirm the validity of our work, the result is compared with that calculated by the extended Jones matrix method (EJMM). As a result, it turns out that the novel method provides more simple and rigorous simulation results than the EJMM.

• Journal of Preventive Medicine and Public Health
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• 제27권2호
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• pp.226-229
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• 1994

In hypertensives, electrocardiographic left ventricular hypertrophy (LVH) is an independent risk factor for cardiovascular disease. Animal and human studies suggest an association between left ventricular mass and dietary sodium (Na) intake. This study determined if dietary Na intake in a homogenous ethnic population is associated with electrocardiographic LVH (S in Vl + R in $V5{\geq}5.5 mV$). Blood pressure (BP), body mass index, EKG, and 24 hour urine Na and potassium (K) excretion were determined in 40 otherwise healthy Korean patients with untreated essential hypertension on the standard Korean diet. Among these variables, only Na excretion (mmol/day) was significantly different between those with and without LVH $[LVH+:357{\pm}50,\;LVH-;\;268{\pm}25(p=0.04]$. Thus, dietary sodium intake may be predictive of electrocardiographic LVH.

• 한국산업융합학회 논문집
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• 제27권2_2호
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• pp.467-473
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• 2024

Metaheuristics' impact is profound across many fields, yet domestic financial portfolio optimization research falls short, particularly in asset allocation. This study delves into metaheuristics for portfolio optimization, examining theoretical and practical benefits. Findings indicate portfolios optimized via metaheuristics outperform the Dow Jones Index in Sharpe ratios, underscoring their potential to enhance risk-adjusted returns significantly. Tabu search, in comparison to Simulated Annealing, demonstrates superior performance by efficiently navigating the search space. Despite these advancements, practical application remains challenging due to the complexities in metaheuristic implementation. The study advocates for broader algorithmic exploration, including population-based metaheuristics, to refine asset allocation strategies further. This research marks a step towards optimizing portfolios from an extensive array of financial assets, aiming for maximum efficacy in investment outcomes.

• 디지털융복합연구
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• 제18권1호
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• pp.121-127
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• 2020

본 연구는 벤처기업들이 내부통제운영시스템을 안정적으로 운영하는 경우 회계정보에 긍정 혹은 부정적인 영향과 같은 상호 밀접한 관련성이 있는지를 검증하기 위해 GEM상장기업을 대상으로 분석하였다. 홍콩의 GEM상장기업은 한국의 KOSDAQ시장과 유사한 상장기업으로 한국의 기업들도 상장을 진행하고 있는 증권 시장이다. 본 연구를 수행하기 위해 내부통제시스템의 운영을 평가할 수 있는 내부통제 지수와 회계정보의 질을 평가할 수 있는 재량적 발생액을 통해 회귀분석을 진행하였다. 이익의 조정은 재량적 발생액을 통해 이루어지기 때문에 기업이 인위적으로 미래의 이익을 실현하기 위해 경영자가 의도적으로 변형했는지를 확인하기 위해 수정된 존스(Jones)모형을 이용하였다. 실증 분석에서는 내부통제지수와 회계정보의 질을 평가할 수 있는 재량적 발생액과의 관계정도를 분석 하였으며 상호관련성은 매우 밀접한 것으로 나타났다. 본 연구는 향후 벤처기업의 이익조정 형태와 기업 가치를 평가하는데 유용한 지침을 제공할 수 있으며, 신흥 벤처기업들의 재무적 환경을 이해하는데 도움이 될 것으로 기대된다.

• 한국컴퓨터정보학회논문지
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• 제25권5호
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• pp.47-56
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• 2020

주가지수는 한 국가의 경제 지표뿐만 아니라 투자판단의 지표로도 활용되므로 이를 예측하는 연구가 지속해서 진행되고 있다. 주가지수 예측을 하는 작업은 기술적, 경제적 및 심리적 요인 등이 반영된 것으로 예측의 정확도를 위해서는 복합적 요인을 고려해야 한다. 따라서 지수의 변동에 영향을 미치는 요인들을 선별하여 반영한 주가지수 예측모델연구가 필요하다. 이와 관련한 기존 연구에서는 시장의 변동을 만들어 내는 뉴스 정보 또는 거시 경제 지표를 각각 이용하거나, 몇 가지의 지표 조합만을 반영한 예측 연구가 대부분이었다. 따라서 본 연구에서는 미국 다우존스지수 예측을 위해 뉴스 정보의 감성 분석과 다양한 거시경제지표를 고려하여 효과적인 지표 조합을 제시하고자 한다. 뉴스 정보의 감성 분석은 최신 자연어처리 기법인 BERT와 NLTK VADER를 사용하고, 예측모델은 주가예측모델로 적합하다고 알려진 딥러닝 예측모델 LSTM을 적용하여 가장 효과적인 지표 조합을 제시했다.

• Tribology and Lubricants
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• 제19권4호
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• pp.230-236
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• 2003

In applications such as MEMS and NEMS devices, the adhesion force and contact load may be of the same order of magnitude and the static friction coefficient can be very large. Such large coefficient may result in unacceptable and possibly catastrophic adhesion, stiction, friction and wear. To obtain the static friction coefficient of contacting real surfaces without the assumption of an empirical coefficient value, numerical simulations of the contact load, tangential force, and adhesion force are preformed. The surfaces in dry contact are statistically modeled by a collection of spherical asperities with Gaussian height distribution. The asperity micro-contact model utilized in calculation (the ZMC model), considers the transition from elastic deformation to fully plastic flow of the contacting asperity. The force approach of the modified DMT model using the Lennard-Jones attractive potential is applied to characterize the intermolecular forces. The effect of the surface topography on the static friction coefficient is investigated for cases rough, intermediate, smooth, and very smooth, respectively. Results of the static friction coefficient versus the external force are presented for a wide range of plasticity index and surface energy, respectively. Compared with those obtained by the GW and CEB models, the ZMC model is more complete in calculating the static friction coefficient of rough surfaces.

• 천문학회보
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• 제42권2호
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• pp.69.1-69.1
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• 2017

According to structure formation simulations, weak shocks with typical Mach number, M<3, are expected to form in merging galaxy clusters. The presence of such shocks has been indicated by X-ray and radio observations of many merging clusters. In particular, diffuse radio sources known as radio relics could be explained by synchrotron-emitting electrons accelerated via diffusive shock acceleration (Fermi I) at quasi-perpendicular shocks. Here we also consider possible roles of stochastic acceleration (Fermi II) by compressive MHD turbulence downstream of the shock. Then we explore a puzzling discrepancy that for some radio relics, the shock Mach number inferred from the radio spectral index is substantially larger than that estimated from X-ray observations. This problem could be understood, if shock surfaces associated with radio relics consist of multiple shocks with different strengths. In that case, X-ray observations tend to pick up the part of shocks with lower Mach numbers and higher kinetic energy flux, while radio emissions come preferentially from the part of shocks with higher Mach numbers and higher cosmic ray (CR) production. We also show that the Fermi I reacceleration model with preexisting fossil electrons supplemented by Fermi II acceleration due to postshock turbulence could reproduce observed profiles of radio flux densities and integrated radio spectra of two giant radio relics. This study demonstrates the CR electrons can be accelerated at collisionless shocks in galaxy clusters just like supernova remnant shock in the interstellar medium and interplanetary shocks in the solar wind.

• 디지털산업정보학회논문지
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• 제19권4호
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• pp.179-192
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• 2023

ESG is the hottest topic in recent business management or business administration. In particular, with the release of the IPCC's 6th comprehensive report in 2023, environmental issues have been further raised around the world, and ESG management for sustainable and permanent companies is accelerating by improving social and governance structures, including the environment, and thereby enhancing corporate value. This case study is analyzed based on the theory of sustainable growth, creating shared value, and corporate social responsibility. This study focuses on the case of Samsung Biologics, which is pursuing sustainable growth and management through ESG management. Samsung Biologics is the first Korean company to win the "Terra Carta Seal" award, part of a sustainable market initiative to respond to climate change, and externally, it has acquired the Dow Jones Sustainability Index, acquired the KCGS ESG comprehensive evaluation A grade, acquired the CDP B grade, and acquired the EcoVadis Gold grade. It has joined the Sustainable Market Initiative launched by King Charles III since the World Economic Forum in 2020 to chair the Supply Chain. It has joined RE100, TCFD, and UN Global Compact to lead sustainable management through ESG activities. Therefore, we would like to take a practical approach to ESG management strategies for sustainable growth through the example of this company.

• Archives of Reconstructive Microsurgery
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• 제24권2호
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• pp.62-67
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• 2015

Purpose: Pollicization typically involves surgical migration of the index finger to the position of the thumb. This procedure facilitates the conversion of a useless hand into a well-functioning one in patients who are not amenable to the toe-to-hand transfer. However, middle finger pollicization has been rarely reported. Materials and Methods: We reconstructed a thumb by immediate pollicization of the remnants of the middle finger in two patients who sustained a tumor and a trauma, respectively. The former, after cancer ablation was performed, has not been reported literally, and the latter involved free devitalized pollicization of the middle finger using a microsurgical anastomosis. The distal third extensor communis tendon was sutured to the proximal extensor pollicis longus tendon and the distal flexor digitorum superficialis and profundus were sutured to the proximal flexor pollicis longus. The abductor pollicis brevis tendon was sutured to the distal end of the first palmar interosseous muscle. Coaptation of the third digital nerve and the superficial radial nerve branch was performed. Results: Patients showed uneventful postoperative courses without complication such as infection or finger necrosis. Based on the principles of pollicization, a wide range of pinch and grasp movements was successfully restored. They were pleased with the functional and cosmetic results. Conclusion: Although the index finger has been the digit of choice for pollicization, we could also use the middle finger on specific occasions. This procedure provides an excellent option for the reconstruction of a mutilated thumb and could be performed advantageously in a single step.

• 한국융합학회논문지
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• 제9권11호
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• pp.307-313
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• 2018

본 연구는 급변하는 비즈니스 환경에서 기업의 내부통제시스템의 도입과 운영이 기업의 회계정보에 미치는 영향을 분석하였다. 본 연구를 수행하기 위해 내부통제와 회계정보의 유용성에 관한 선행연구를 종합적으로 분석하여 본 연구 목적에 맞게 연구모델을 적용하여 실증분석을 실시하였다. 본 연구는 중국기업을 대상으로 내부통제시스템의 구성 요소를 중심으로 내부통제평가지수를 이용하여 수정된 존스(Jones) 모형의 재량적 발생액을 기본으로 변수간의 관계정도를 분석하였다. 실증분석에서는 내부통제의 운영이 회계정보의 유용성 대용변수인 재량적 발생액에 음의 영향관계가 있는 것으로 분석되었다. 또한 내부통제시스템의 위험관리 요인도 회계정보의 유용성에 음의 상관관계가 있는 것으로 분석되었다. 이러한 결과는 재량적 발생액이 적정하고 유의적으로 조정되어 회계정보의 유용성에 긍정적인 영향을 주고 있는 주요 요인으로 추정 할 수 있다. 본 연구 결과는 내부통제의 도입과 운용이 중요해지고 있는 많은 기업에 내부통제시스템의 긍정적인 기능을 제시할 수 있으며, 외국계 기업의 내부통제의 운용과 재량적 발생액과의 관계연구에도 유용한 지침을 제공할 수 있을 것으로 기대된다.