• The Journal of Asian Finance, Economics and Business
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• 제8권4호
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• pp.339-347
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• 2021

This study aims to forecast the exchange rate by a combination of different models as proposed by Poon and Granger (2003). For this purpose, we include three univariate time series models, i.e., ARIMA, Naïve, Exponential smoothing, and one multivariate model, i.e., NARDL. This is the first of its kind endeavor to combine univariate models along with NARDL to the best of our knowledge. Utilizing monthly data from January 2011 to December 2020, we predict the Pakistani Rupee against the US dollar by a combination of different forecasting techniques. The observations from M1 2020 to M12 2020 are held back for in-sample forecasting. The models are then assessed through equal weightage and var-cor methods. Our results suggest that NARDL outperforms all individual time series models in terms of forecasting the exchange rate. Similarly, the combination of NARDL and Naïve model again outperformed all of the individual as well as combined models with the lowest MAPE value of 0.612 suggesting that the Pakistani Rupee exchange rate against the US Dollar is dependent upon the macro-economic fundamentals and recent observations of the time series. Further evidence shows that the combination of models plays a vital role in forecasting, as stated by Poon and Granger (2003).

• The Journal of Asian Finance, Economics and Business
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• 제8권1호
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• pp.599-608
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• 2021

The oil and gas industry is widely known as a vital engine of Vietnam development, stimulating researchers to examine the association of various factors with this industry. The aim of this study is to identify the relationship between different variables affecting profitability of the firms in the oil and gas sector in Vietnam. The total of 203 samples were collected from 29 companies listed on Vietnam Stock Market during a 6-year period from 2012 to 2018. Informed by prior research, this investigation employs financial leverage (FL), government ownership (GOV), dividend payout (DIV), fixed assets to total assets (FA) and exchange rate (EXR) as independent variables, while the profit is described by return-on-assets (ROA). The study results show that there are four factors that have an impact on ROA, namely, leverage, government ownership, dividend, and exchange rate. Whereas leverage and exchange rate have negative influence on ROA, government ownership and dividend payment have a positive effect. The findings of this study suggest that high debt ratio in capital structure and the negative effect of exchange rate on their companies' efficiency can adversely affect the profit of enterprises. Also, plausible extent of government ownership and dividend payment could also be considered to optimize corporate performance.

• Journal of Ginseng Research
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• 제42권3호
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• pp.389-399
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• 2018

Background: The antioxidant effects of Panax ginseng have been reported in several articles; however, little is known about the antimelanogenesis effect, skin-protective effect, and cellular mechanism of Panax ginseng, especially of P. ginseng calyx. To understand how an ethanol extract of P. ginseng berry calyx (Pg-C-EE) exerts skin-protective effects, we studied its activities in activated melanocytes and reactive oxygen species (ROS)-induced keratinocytes. Methods: To confirm the antimelanogenesis effect of Pg-C-EE, we analyzed melanin synthesis and secretion and messenger RNA and protein expression levels of related genes. Ultraviolet B (UVB) and hydrogen peroxide ($H_2O_2$) were used to induce cell damage by ROS generation. To examine whether this damage is inhibited by Pg-C-EE, we performed cell viability assays and gene expression and transcriptional activation analyses. Results: Pg-C-EE inhibited melanin synthesis and secretion by blocking activator protein 1 regulatory enzymes such as p38, extracellular signal-regulated kinases (ERKs), and cyclic adenosine mono-phosphate response element-binding protein. Pg-C-EE also suppressed ROS generation induced by $H_2O_2$ and UVB. Treatment with Pg-C-EE decreased the expression of matrix metalloproteinases, mitogen-activated protein kinases, and hyaluronidases and increased the cell survival rate. Conclusion: These results suggest that Pg-C-EE may have antimelanogenesis properties and skin-protective properties through regulation of activator protein 1 and cyclic adenosine monophosphate response element-binding protein signaling. Pg-C-EE may be used as a skin-improving agent, with moisture retention and whitening effects.

• 보건의료산업학회지
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• 제7권3호
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• pp.287-296
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• 2013

The aim of this study was to compare the regional difference of death from intentional self-harm. The analysis was based on data of intentional self-harm deaths (31,450) from the 2010-2011 vital statistics of Korea. The suicide rate (per 100,000 population) was 46.2 in male and 22.3 in female. Gender ratio (male / female) of suicide rate was 2.07, and Jeju province had the lowest gender ratio (1.82), and Chungbuk province had the highest gender ratio (2.42). In the age-gender standardized death rate (per 100,000) of self-harm by region, the highest suicide rate was observed in Gangwon province (44.8) and Chungnam province (44.3), and the lowest in Seoul metropolitan city (28.9) and Ulsan metropolitan city (29.2). There was a significant increase in the rate of suicide in city areas (odds ratio: 1.11, 95% CI: 1.08-1.13), county areas (1.62, 1.56-1.67) as compared with the rate of suicide in metropolitan areas. The commonest methods of suicide were hanging (53.7 percent), self-poisoning by pesticides (16.8 percent) and jumping from a height (14.3 percent). The methods used for suicide differed between rural (county) and urban areas (metropolitan city and city). In county areas, 43 percent of suicides used pesticides as compared to only 7-18 percent of those in urban areas. In urban areas, jumping was more common (13-17 percent vs. 6 percent). There were no difference in hanging between urban and rural areas. The odds ratio of death by pesticides was 9.86 in rural areas compared with death rate of metropolitan areas. The odds ratio of death by jumping was 0.59 in rural compared with death rate of metropolitan areas.

• 한국임상수의학회지
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• 제25권3호
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• pp.170-175
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• 2008

The present study was performed to investigate the anesthetic or analgesic effect of tiletamine-zolazepam (TZ) and electro acupuncture analgesia (EAA) in cats. Twelve healthy cats were randomly assigned to receive either TZ or EA. TZ group cats with weight of $3.65{\pm}0.48kg$ received 10.0 mg/kg of TZ intramuscularly. EA group cats with weight of $3.62{\pm}0.52kg$ received 5V, 30Hz and 60 minutes of EA. The acupoints used were Tian-ping (GV-5, +), Bai-hui (GV-20, -). Therefore, after and before experiment, some serum chemistry profiles (alkaline phospatase, aspartate aminotransferase, alanine aminotransferase, glucose and total protein) and change of vital signs (rectal temperature, heart rate, respiratory rate) were examined. All cats were examined pre, and 5, 25, 65 and 105 minutes after administration of TZ or operation of EA. The cats in EA group showed a smaller change in rectal temperature, heart rate and respiratory rate than in the TZ group (p<0.05). In both groups, total protein concentration was constant throughout the period of anesthesia, and the serum glucose increased gradually throughout the period of anesthesia. However, the cats in EA group showed a smaller change in alkaline phospatase, aspartate aminotransferase and alanine aminotransferase within the limit of safety than in the TZ group (p<0.05). While coming to induction, the TZ group took a mean $2.4{\pm}0.7$ minutes to achieve sternal recumbency, compared with $10.5{\pm}2.1$ minutes by the EA group, and $3.2{\pm}0.6$ minutes to achieve lateral recumbency, compared with $18.8{\pm}1.9$ minutes by the EA group (p<0.05). When recovering from anesthesia, the TZ group took $164.3{\pm}17.9$ minutes to achieve sternal position time, compared with $67.7{\pm}4.6$ minutes by the EA group, and $202.0{\pm}15.7$ minutes to stand, compared with $73.0{\pm}6.1$ minutes for the EA group (p<0.05). In this study, the cats anesthetized with EA showed a more rapid recovery rather than the cats under TZ anesthesia. Also, there do not appear to be any negative physiologic effects associated with acupuncture-induced surgical analgesia. So, it was considered that EAA may be used effectively in shock, debilitated cats, as compared to TZ.

• 원예과학기술지
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• 제28권5호
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• pp.768-776
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• 2010

본 실험은 thermal units을 이용하여 single-stemmed rose($Rosa$ $hybrida$ L.) 'Vital'의 초장, 생체중 및 총엽면적과 각 생육단계에 도달하는 시간을 예측하고, 장미의 신초발달 모델을 개발하기 위해 수행하였다. 기저온도($T_b$), 적정온도($T_{opt}$), 및 최대온도($T_{max}$)는 신초의 발달율과 평균온도의 회귀를 통해 예측하였다. 삽목에서 정식(CT-TP)까지의 생육단계에 대한 신초의 발달율은 linear 함수인 $R_b(d^{-1})$ = -0.0089 + $0.0016{\cdot}Temp$으로 나타났다. 정식에서 수확(TP-HV)까지의 생육단계에서 신초의 발달율은 parabolic 함수인 $R_h(d^{-1})$ = $-0.0001{\cdot}Temp^2$ + $0.0054{\cdot}Temp$ - 0.0484으로 나타낼 수 있었다. $T_b$, $T_{opt}$ 및 $T_{max}$는 각각 5.56, 27.0, 및 $42.7^{\circ}C$으로 나타났다. Tb값 $5.56^{\circ}C$은 single-stemmed rose의 신초발달에 대한 온도함수인 thermal units 계산에 이용되었다. 엽수, 엽면적 및 엽중은 삽목시기에 상관없이 sigmoid curve를 나타내었다. 엽면적(LA) 모델은 thermal units를 사용하여 sigmoid 함수, LA = 578.7 $[1+(thermal units/956.1)^{-8.54}]^{-1}$로 기술할 수 있었다. 삽목에서 정식(CT-TP)과 정식에서 수확(TP-HV)까지의 생육단계에 있어서 요구되는 평균 thermal units($^{\circ}C{\cdot}d$)는 각각 $426{\pm}42(^{\circ}C{\cdot}d)$과 $783{\pm}24(^{\circ}C{\cdot}d$)였다.

• Imaging Science in Dentistry
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• 제53권4호
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• pp.313-323
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• 2023

Purpose: This study aimed to investigate the potential factors that could affect the reduction rate of odontogenic cysts following decompression using cone-beam computed tomography (CBCT) for 3-dimensional volumetric analysis. Materials and Methods: The study sample consisted of CBCT images of 41 individuals who underwent decompression of odontogenic cysts at the Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Chulalongkorn University, between 2010 and 2022. Preoperative and postoperative CBCT results were collected, and a volumetric analysis was conducted to evaluate the differences in the reduction rate and the percentage of volume reduction of cystic lesions based on different parameters. Correlations between these parameters were analyzed to determine associations. Results: In this study, the average time of decompression for odontogenic cysts was 316 days. Males demonstrated a higher reduction rate than females (P<0.05). The reduction rate was directly proportional to initial cyst volume, with higher reduction rates for cysts with large initial volume than those with small initial volume (P<0.05). Spearman's rank correlation coefficient indicated a weak positive correlation between the initial cyst volume and the duration of decompression. Additionally, a strong positive correlation was observed between the initial volume and the reduction rate. Conclusion: Knowledge of the reduction rate of odontogenic cysts is vital for surgeons to evaluate the duration of decompression before enucleation and to determine a definitive treatment plan. Sex and initial lesion volume had significant effects on the reduction rate.

• 제어로봇시스템학회논문지
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• 제10권12호
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• pp.1305-1311
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• 2004

This study presents a mathematical model and a sliding mode observer of the injection system for common rail diesel engines. The injector model consists of three subsystems: the actuator subsystem, the mechanical subsystem, and the hydraulic subsystem. In the actuator subsystem, the constitutive relations of piezoelectricity are used to model the actuator made up of piezoelectric material. Based on the proposed model, the observer estimates the injection rate and injection timing, and can play a vital role of sensorless control of fuel injection in the near future. The sliding mode theory is applied to the observer design in order to overcome model uncertainties. The injector model and observer are evaluated through the injector experiments. The simulation results of the injector model are in good agreement with the experimental data. The sliding mode observer can effectively estimate the injection timing and the injection rate of the injector.

• 성인간호학회지
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• 제20권2호
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• pp.311-320
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• 2008

Purpose: The study was done to analyze the effects of aroma inhalation method on preoperative anxiety of abdominal surgical patients. Methods: The research design was a nonequivalent control group non-synchronized design. The data were collected from July 25 to October 21, 2005 at C Medical Center in Seoul. The patients were divided into two group of 24 subjects each. In order for measuring the all patient's anxiety before operation and aroma inhalation, Spidlberger(1975) trait anxiety, VAS(visual analogue scale) state anxiety, blood pressure, pulse rate were taken. After experimental group was taken aroma inhalation, VAS state anxiety, blood pressure, pulse rate were measured for two group. Results: After aroma inhalation, VAS state anxiety level, systolic blood pressure, diastolic blood pressure, pulse rate of the experimental group were decreased significantly than those of control group(p = .000, p = .000, p = .030. p = .000). Conclusion: The aroma inhalation method can be considered an effective nursing intervention that relieves the preoperative anxiety of abdominal surgical patients and stabilizes vital signs.

• 재활간호학회지
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• 제6권2호
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• pp.152-163
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• 2003

Purpose; This study was done to investigate the effect of foot reflexology on vital signs, general fatigue, foot fatigue, mood, and blood glucose levels in noninsulin dependent patients. Method: The Research design of this study was nonequivalent control group quasi-experimental design. 18 patients were assigned to the experimental group, 24 patients to the control group. The data were obtained diaberic patients with ambulatory endocrine outpatients clinic patients from 40 years old to 70 years old. Experimental groups received foot reflex massage for 30minutes three times/week every other days, and Control groups did not received foot reflex massage. The dependent variables were blood pressure, pulse rate, visual analogue scale for general fatigue, foot fatigue, mood, and blood sugar levels. Data were analyzed with $X^2$ test, t-test and repeated measure ANOVA at .0.05 level of significance. Results: There were significant difference in the pulse rate, general fatigue, foot fatigue and mood according to group and time between pre and post foot reflexology. But this research did not prove to decrease blood sugar levels. Conclusions : Foot reflexology can imorove pulse rate, general and foot fatigue, and mood status in diabetus patients. So further research need to explore the effect of decreasing of blood sugar levels.