• Steel and Composite Structures
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• 제39권1호
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• pp.51-64
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• 2021

This paper presents a high-order shear and normal deformation theory for the bending of FGM plates. The number of unknowns and governing equations of the present theory is reduced, and hence makes it simple to use. Unlike any other theory, the number of unknown functions involved in displacement field is only four, as against five or more in the case of other shear and normal deformation theories. Based on the novel shear and normal deformation theory, the position of neutral surface is determined and the governing equilibrium equations based on neutral surface are derived. There is no stretching-bending coupling effect in the neutral surface-based formulation, and consequently, the governing equations of functionally graded plates based on neutral surface have the simple forms as those of isotropic plates. Navier-type analytical solution is obtained for functionally graded plate subjected to transverse load for simply supported boundary conditions. The accuracy of the present theory is verified by comparing the obtained results with other quasi-3D higher-order theories reported in the literature. Other numerical examples are also presented to show the influences of the volume fraction distribution, geometrical parameters and power law index on the bending responses of the FGM plates are studied.

• Safety and Health at Work
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• 제13권1호
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• pp.23-31
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• 2022

Background: Potato is the main crop of Ardabil Plain (accounting for one-fifth of potato production in Iran). Its health hazard risk to farmers is rising due to the increasing rate of pesticide use. The present study analyzes potato farmers' health hazard risk in the use of chemical pesticides. Methods: The rate of pesticide use by farmers (n = 370) was first compared with the recommended dosage (on pesticide label). Then, a composite index was employed to estimate the health hazard risk of farmers during pesticide use, and the variables accounting for pesticide overuse and nonoveruse were analyzed. Safety behavior was examined in four steps, namely of pesticide purchase and storage, preparation, application, and postapplication. Results: It was found that 74.6 percent of potato farmers used pesticides in higher concentrations than the recommended dosage. The higher average rate of pesticide use versus recommendation (label instruction) was related to Chlorpyrifos and Trifluralin, and the highest average health hazard risk among farmers was related to the use of Chlorpyrifos and Metribuzin. Farmers with a higher risk of health hazard displayed much lower safety behavior than the other farmers at all steps of pesticide use. Conclusion: The most important variables discriminating the health hazard risk of farmers' overuse included health behavior identity, attitude, knowledge and awareness, and cues to action. Therefore, using social media, holding local exhibitions, and engaging local leaders and skilled farmers in the region to improve farmers' attitudes and health behavior identity toward the dangers of chemical pesticides can play a significant role in motivating farmers' display of overuse preventive behaviors.

• 문화기술의 융합
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• 제7권4호
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• pp.807-814
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• 2021

코로나-19로 인해 경제 활동이 낮아지고 주식 시장이 침체하면서 주식 투자를 통해 또 다른 소득을 마련하기 위해 많은 사람이 주식 시장에 뛰어들고 있다. 사람들의 관심이 높아지면서 더 많은 수익을 얻기 위한 주가 분석 연구가 많이 진행되고 있다. 주가는 종목별 변동의 흐름이 다르므로 각 주가 종목별로 독립적이며 일관적으로 분석할 필요가 있다. 이러한 문제를 해결하고자 본 논문에서는 강화학습 기법 중 하나인 Asynchronous Advantage Actor-Critic(A3C)를 이용하여 주가를 분석할 수 있는 모델 및 서비스를 설계 및 구현하였다. 주식 시장 데이터로 종목별 주가 및 국채, 코스피와 같은 외부 요인들을 반영하였다. 또한 웹페이지 제작을 통해 시각화한 정보를 제공하여 투자자들이 투자 기업에 대한 재무제표를 비롯하여 국내외 경제 및 정치의 흐름을 모두 분석하지 않고도 안전한 투자를 할 수 있도록 서비스를 제공한다.

• Archives of Plastic Surgery
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• 제49권5호
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• pp.633-641
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• 2022

Introduction In chronic facial palsy, synkinetic muscle overactivity and shortening causes muscle stiffness resulting in reduced movement and functional activity. This article studies the role of multimodal therapy in improving outcomes. Methods Seventy-five facial palsy patients completed facial rehabilitation before being successfully discharged by the facial therapy team. The cohort was divided into four subgroups depending on the time of initial attendance post-onset. The requirement for facial therapy, chemodenervation, or surgery was assessed with East Grinstead Grade of Stiffness (EGGS). Outcomes were measured using the Facial Grading Scale (FGS), Facial Disability Index, House-Brackmann scores, and the Facial Clinimetric Evaluation scale. Results FGS composite scores significantly improved posttherapy (mean-standard deviation, 60.13 ± 23.24 vs. 79.9 ± 13.01; confidence interval, -24.51 to -14.66, p < 0.0001). Analysis of FGS subsets showed that synkinesis also reduced significantly (p < 0.0001). Increasingly, late clinical presentations were associated with patients requiring longer durations of chemodenervation treatment (p < 0.01), more chemodenervation episodes (p < 0.01), increased doses of botulinum toxin (p < 0.001), and having higher EGGS score (p < 0.001). Conclusions This study shows that multimodal facial rehabilitation in the management of facial palsy is effective, even in patients with chronically neglected synkinesis. In terms of the latency periods between facial palsy onset and treatment initiation, patients presenting later than 2 years were still responsive to multimodal treatment albeit to a lesser extent, which we postulate is due to increasing muscle contracture within their facial muscles.

• Steel and Composite Structures
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• 제43권6호
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• pp.821-837
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• 2022

This research is devoted to study the effects of humidity and temperature on the bending behavior of functionally graded (FG) ceramic-metal porous plates resting on Pasternak elastic foundation using a quasi-3D hyperbolic shear deformation theory developed recently. The present plate theory with only four unknowns, takes into account both transverse shear and normal deformations and satisfies the zero traction boundary conditions on the surfaces of the functionally graded plate without using shear correction factors. Material properties of porous FG plate are defined by rule of the mixture with an additional term of porosity in the through-thickness direction. The governing differential equations are obtained using the "principle of virtual work". Analytically, the Navier method is used to solve the equations that govern a simply supported FG porous plate. The obtained results are checked by comparing the results determined for the perfect and imperfect FG plates with those available in the scientific literature. Effects due to material index, porosity factors, moisture and thermal loads, foundation rigidities, geometric ratios on the FG porous plate are all examined. Finally, this research will help us to design advanced functionally graded materials to ensure better durability and efficiency for hygro-thermal environments.

• Steel and Composite Structures
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• 제42권6호
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• pp.805-826
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• 2022

The free and live load-forced vibration behaviour of porous functionally graded (PFG) higher order nanobeams in the thermal and magnetic fields is investigated comprehensively through this work in the framework of nonlocal strain gradient theory (NLSGT). The porosity effects on the dynamic behaviour of FG nanobeams is investigated using four different porosity distribution models. These models are exploited; uniform, symmetrical, condensed upward, and condensed downward distributions. The material characteristics gradation in the thickness direction is estimated using the power-law. The magnetic field effect is incorporated using Maxwell's equations. The third order shear deformation beam theory is adopted to incorporate the shear deformation effect. The Hamilton principle is adopted to derive the coupled thermomagnetic dynamic equations of motion of the whole system and the associated boundary conditions. Navier method is used to derive the analytical solution of the governing equations. The developed methodology is verified and compared with the available results in the literature and good agreement is observed. Parametric studies are conducted to show effects of porosity parameter; porosity distribution, temperature rise, magnetic field intensity, material gradation index, non-classical parameters, and the applied moving load velocity on the vibration behavior of nanobeams. It has been showed that all the analyzed conditions have significant effects on the dynamic behavior of the nanobeams. Additionally, it has been observed that the negative effects of moving load, porosity and thermal load on the nanobeam dynamics can be reduced by the effect of the force induced from the directed magnetic field or can be kept within certain desired design limits by controlling the intensity of the magnetic field.

• 지능정보연구
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• 제28권4호
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• pp.81-94
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• 2022

최근 고액의 실물자산이나 채권을 분할하여 여러 투자자가 공동으로 투자하는 이른바 조각투자가 인기를 얻고 있다. 2016년 설립된 뮤직카우는 음원 유통에 따른 저작권료 참여 청구권을 조각투자할 수 있는 서비스를 세계 최초로 시작하였다. 본 연구에서는 딥러닝 알고리즘 중 하나인 LSTM 모델을 사용하여 뮤직카우에서 거래되는 저작권료 참여 청구권의 가격을 예측하는 연구를 진행하였다. 청구권의 이전 가격과 거래량, 저작권료와 같은 청구권과 관련된 변수 외에도, 음악저작권료 참여 청구권 시장 상황을 나타내는 종합 지표와 경제 상황을 반영하는 환율, 국고채 금리, 한국종합주가지수도 변수로 사용하였다. 연구 결과 상대적으로 거래량이 낮은 조각투자의 사례에서도 LSTM 모델이 거래가격을 잘 예측하는 것을 확인할 수 있었다.

• 반도체디스플레이기술학회지
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• 제21권1호
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• pp.79-84
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• 2022

As various flexible display products are released, the demand for high-performance colorless and transparent polyimide (CPI) film is continuously increasing. The primary purpose of this study is to establish a systematic procedure for optimizing the optical performance of CPI films by applying the response surface method. After selecting three key factors (monomer type, stirring time for varnish synthesis, and maximum temperature of vacuum furnace for film production) affecting optical performance based on experiences and references, CPI films were manufactured according to the experimental sequence designed by the central composite design, and then the yellowness index (YI) and optical transmittance (Tr) of the films were measured. When producing a CPI film by pouring varnish into a petri dish, the change in optical properties according to thickness should be considered, and there was a meaningful linear relationship between YI and Tr. The species of monomer and the maximum temperature were the critical factors that had an influence on YI and Tr, respectively. It is expected that the procedure proposed in this study can serve as a starting point for CPI film optimization studies considering the other factors that were not considered and responses such as thermal properties.

• 아태비즈니스연구
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• 제13권1호
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• pp.153-166
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• 2022

Purpose - ESG(Environmental, Social and Governance) rating is an indicator to predict the sustainable development and long-term value creation of enterprises, which is becoming more and more important. This study divided the ESG rating into each sector(E, S and G) to identify which ESG elements are effective in enhancing enterprise value according to the characteristics of the enterprise, which is different from previous studies. Design/methodology/approach - In this study, Bloomberg ESG Disclosure Score was used to empirically analyze the relationship between ESG ratings and corporate value by taking the listed companies of China's Shanghai Composite Index from 2017 to 2020 as the object. Findings - First, the relationship between ESG ratings and enterprise value shows a statistically significant positive correlation, which supports the results of previous studies. Second, the analysis results from the classification of ownership structure of enterprises (state-owned enterprises and non-state-owned enterprises) show that compared with state-owned enterprises, the ESG ratings of non-state-owned enterprises is more closely related to enterprise value. Third, the analysis of various industries (manufacturing and non-manufacturing) shows that compared with manufacturing, ESG scores of non-manufacturing has a more positive effect on enterprise value. Lastly, the analysis by industry type (heavy-contaminated companies, non-contaminated companies) confirmed that ESG scores of non-contaminated companies has a positive effect on corporate value than heavy-contaminated companies. Research implications or Originality - This study classified ESG evaluation grades(E, S and G) for listed companies in China and analyzed in detail how they affect corporate value according to corporate characteristics, drawing implications for what ESG indicators should be focused on to increase corporate value.

• 동의신경정신과학회지
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• 제33권3호
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• pp.259-266
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• 2022

Objectives: The combination of Harm-Avoidance (HA) and Self-Directedness (SD) of Temperament and Character Inventory (TCI) has been reported pivotal for mental health; however its clinical usefulness in integrative medicine has not sufficiently reported. The purpose of this study was to illustrate multi-phasic mental health of subjective satisfaction with life, emotional well-being, and psychopathology, following the HA-SD profile groups. Methods: A total of 527 Korean university students reported HA and SD scores as to render their HA-SD profile, and multi-phasic mental health characteristics using Satisfaction with Life Scale (SWLS), Positive Affect and Negative Affect Schedule (PANAS), and Beck Depression Inventory (BDI) with composite well-being scales of SC (Sum of Self-Directedness and Cooperativeness score) and HI (Happiness Index, subtraction of Negative Affect (NA) score from Positive Affect (PA) score) as standardized. Pearson's correlation was used to report correlation coefficient, and the ANCOVA with age and sex as covariates, to show significant differences in mental health and well-being between the HA-SD profile groups. Results: The HA-SD profile groups showed distinctive multi-phasic mental health characteristics; health related scores of SWLS, PA, SC and HI decreased following the order of hS (low HA and high SD), HS (high HA and high SD), hs (low HA and low SD) and Hs (high HA and low SD) profile groups; however the non-health related scores of NA and BDI showed contrasting order. Conclusions: The HA-SD profile was found to be clinically useful for examining multi-phasic mental health and well-being status, and the TCI may be an imperative personality inventory for integrative medicine.