• 아태비즈니스연구
• /
• 제14권4호
• /
• pp.233-254
• /
• 2023

Purpose - This study aims to verify whether the effect of tax avoidance on corporate value is non-linear in the Korean financial markets. Design/methodology/approach - This study believes that the cause of the inconsistent empirical analysis results of previous studies that verified the relationship between tax avoidance and firm value may be an error in assuming linearity, and verifies whether a nonlinear relationship exists. The sample company in this study is a December settlement corporation listed on the Korean stock market, and the analysis period is from 2000 to 2021. In the empirical analysis model, Tobin's Q is used as a proxy for corporate value, tax avoidance is used as the main independent variable, and a regression model is designed with corporate size, growth rate, and debt ratio set as control variables. Findings - As a result of the empirical analysis, it can be confirmed that there is an inverted U-shaped nonlinear relationship between tax avoidance and corporate value. In the additional analysis using Ohlson (1995) firm valuation model for the robustness of the results of the empirical analysis, the same nonlinear value relationship between tax avoidance can be confirmed. Research implications or Originality - This study is considered to be meaningful in that it verifies the non-linear relationship of tax avoidance, which has not been attempted in previous studies. The meaning of the inverted U-shaped nonlinear relationship presented in this study is that corporate tax avoidance acts as a factor that increases corporate value up to a certain level, but rather becomes a factor that decreases corporate value when it exceeds a critical point. These results are expected to provide new perspectives and perspectives on tax avoidance to companies belonging to the Korean capital market.

• Journal of Pharmaceutical Investigation
• /
• 제35권3호
• /
• pp.137-142
• /
• 2005

A rapid, selective and sensitive reversed-phase HPLC method for the determination of glipizide in human serum was validated and applied to the pharmacokinetic study of glipizide. Glipizide and internal standard, tolbutamide, were extracted from human serum by liquid-liquid extraction with benzene and analyzed on a Nova Pak $C_{18}\;60{\AA}$ column with the mobile phase of acetonitrile-potassium dihydrogen phosphate (10 mM, pH 3.5) (4:6, v/v). Detection wavelength of 275 nm and flow rate of 0.7 ml/min were fixed for the study. The assay robustness for the changes of mobile phase pH, organic solvent content, and flow rate was confirmed by $3^3$ factorial design using a fixed glipizide concentration (500 ng/ ml) with respect to its peak area and retention time. And also, the ruggedness of this method was investigated at three different laboratories using same quality control (QC) samples. This method showed linear response over the concentration range of 10-1000 ng/ml with correlation coefficient greater than 0.999. The lower limit of quantitation using 0.5 ml of serum was 10.0 ng/ml, which was sensitive enough for pharmacokinetic studies. The overall accuracy of the quality control samples ranged from 82.6 to 105.0% for glipizide with overall precision (% C.V.) being 1.13-13.20%. The percent recovery for human serum was in the range of 85.2 93.5%. Stability studies showed that glipizide was stable during storage, or during the assay procedure in human serum. The peak area and retention time of glipizide were not significantly affected by the changes of mobile phase pH, organic solvent content, and flow rate under the conditions studied. This method showed good ruggedness (within 15% C.V.) and was successfully used for the analysis of glipizide in human serum samples for the pharmacokinetic studies at three different laboratories, demonstrating the suitability of the method.

• Journal of Pharmaceutical Investigation
• /
• 제35권6호
• /
• pp.437-443
• /
• 2005

A rapid, selective and sensitive reversed-phase HPLC method for the determination of a major metabolite of terfenadine, fexofenadine, in human serum was developed, validated, and applied to the pharmacokinetic study of terfenadine. Fexofenadine and internal standard, haloperidol were extracted from human serum by liquid-liquid extraction with acetonitrile and analyzed on a $Symmetry^{TM}$ C8 column with the mobile phase of 1% triethylamine phosphate (pH 3.7)-acetonitrile (67:33, v/v, adjusted to pH 5.6 with triethylamine). Detection wavelength of 230 nm for excitation, 280 nm for emission and flow rate of 1.0 mL/min were fixed for the study. The assay robustness for the changes of mobile phase pH, organic solvent content, and flow rate was confirmed by $3^{3}$ factorial design using a fixed fexofenadine concentration (50 ng/mL) with respect to its peak area and retention time. In addition, the ruggedness of this method was investigated at three different laboratories using same quality control (QC) samples. This method showed linear response over the concentration range of 10-500 ng/mL with correlation coefficients greater than 0.999. The lower limit of quantification using 0.5 mL of serum was 10 ng/mL, which was sensitive enough for the pharmacokinetic studies of terfenadine. The overall accuracy of the quality control samples ranged from 95.70 to 114.58% for fexofenadine with overall precision (% C.V.) being 3.53-14.39%. The relative mean recovery of fexofenadine for human serum was 90.17%. Stability studies (freeze-thaw, short-term, extracted serum sample and stock solution) showed that fexofenadine was stable during storage, or during the assay procedure in human serum. However, the storage at $-70^{\circ}C$ for 4 weeks showed that fexofenadine was not stable. The peak area and retention time of fexofenadine were not significantly affected by the changes of mobile phase pH, organic solvent content, and flow rate under the conditions studied. This method showed good ruggedness (within 15% C.V.) and was successfully used for the analysis of fexofenadine in human serum samples for the pharmacokinetic studies of orally administered Tafedine tablet (60 mg as terfenadine) at three different laboratories, demonstrating the suitability of the method.

• Journal of Pharmaceutical Investigation
• /
• 제35권4호
• /
• pp.265-271
• /
• 2005

A rapid, selective and sensitive reversed-phase HPLC method for the determination of etodolac in human serum was developed, validated, and applied to the pharmacokinetic study of etodolac. Etodolac and internal standard, ibuprofen were extracted from human serum by liquid-liquid extraction with hexane/isopropanol (95:5, v/v) and analyzed on a Luna C18(2) column with the mobile phase of 1% aqueous acetic acid-acetonitrile (4:6, v/v). Detection wavelength of 227 nm and flow rate of 1.0 mL/min were fixed for the study. The assay robustness for the changes of mobile phase pH, organic solvent content, and flow rate was confirmed by $3^3$ factorial design using a fixed etodolac concentration $(1\;{\mu}g/mL)$ with respect to its peak area and retention time. And also, the ruggedness of this method was investigated at three different laboratories using same quality control (QC) samples. This method showed linear response over the concentration range of $0.05-40\;{\mu}g/mL$ with correlation coefficients greater than 0.999. The lower limit of quantification using 0.5 mL of serum was 0.05 ${\mu}g/mL$, which was sensitive enough for pharmacokinetic studies. The overall accuracy of the quality control samples ranged from 92.00 to 110.00% for etodolac with overall precision (% C.V.) being 1.08-10.11%. The percent recovery for human serum was in the range of 76.73-115.30%. Stability studies showed that etodolac was stable during storage, or during the assay procedure in human serum. The peak area and retention time of etodolac were not significantly affected by the changes of mobile phase pH, organic solvent content, and flow rate under the conditions studied. This method showed good ruggedness (within 15% C.V.) and was successfully used for the analysis of etodolac in human serum samples for the pharmacokinetic studies of orally administered Lodin XL tablet (400 mg as etodolac) at three different laboratories, demonstrating the suitability of the method.

• Journal of Pharmaceutical Investigation
• /
• 제35권6호
• /
• pp.423-429
• /
• 2005

A selective and sensitive reversed-phase HPLC method for the determination of fenoprofen in human serum was developed, validated, and applied to the pharmacokinetic study of fenoprofen calcium. Fenoprofen and internal standard, ketoprofen, were extracted from human serum by liquid-liquid extraction with diethyl ether and analyzed on a Luna C18(2) column with the mobile phase of acetonitrile-3 mM potassium dihydrogen phosphate (32:68, v/v, adjusted to pH 6.6 with phosphoric acid). Detection wavelength of 272 nm and flow rate of 0.25 mL/min were fixed for the study. The assay robustness for the changes of mobile phase pH, organic solvent content, and flow rate was confirmed by $3^{3}$ factorial design using a fixed fenoprofen concentration $(2\;{\mu}g/mL)$ with respect to its peak area and retention time. And also, the ruggedness of this method was investigated at three different laboratories using same quality control (QC) samples. This method showed linear response over the concentration range of $0.05-100\;{\mu}g/mL$ with correlation coefficients greater than 0.999. The lower limit of quantification using 1 mL of serum was $0.05\;{\mu}g/mL$, which was sensitive enough for pharmacokinetic studies. The overall accuracy of the quality control samples ranged from 92.27 to 109.20% for fenoprofen with overall precision (% C.V.) being 5.51-11.71 %. The relative mean recovery of fenoprofen for human serum was 81.7%. Stability (freeze-thaw, short and long-term) studies showed that fenoprofen was not stable during storage. But, extracted serum sample and stock solution were allowed to stand at ambient temperature for 12 hr prior to injection without affecting the quantification. The peak area and retention time of fenoprofen were not significantly affected by the changes of mobile phase pH, organic solvent content, and flow rate under the conditions studied. This method showed good ruggedness (within 15% C.V.) and was successfully used for the analysis of fenoprofen in human serum samples for the pharmacokinetic studies of orally administered Fenopron tablet (600 mg as fenoprofen) at three different laboratories, demonstrating the suitability of the method.

• Journal of Pharmaceutical Investigation
• /
• 제36권1호
• /
• pp.45-51
• /
• 2006

A rapid, selective and sensitive reversed-phase HPLC method for the determination of dipyridamole in human serum was developed, validated, and applied to the pharmacokinetic study of dipyridamole. Dipyridamole and internal standard, loxapine, were extracted from human serum by liquid-liquid extraction with diethyl ether and analyzed on a Nova Pak $C_{I8}$ column with the mobile phase of 40 mM ammonium acetate:methanol:acetonitrile (35:35:30)(v/v/v, pH 7.8). Detection wavelength of 280 nm and flow rate of 1.0 mL/min were fixed for the study. The assay robustness for the changes of mobile phase pH, organic solvent content, and flow rate was confirmed by $3^3$ factorial design using a fixed dipyridamole concentration (50 ng/mL) with respect to its peak area and retention time. And also, the ruggedness of this method was investigated at three different laboratories using same quality control (QC) samples. This method showed linear response over the concentration range of 2-2000 ng/mL with correlation coefficients greater than 0.999. The lower limit of quantification using 0.5 mL of serum was 2 ng/mL, which was sensitive enough for pharmacokinetic studies of dipyridamole. The overall accuracy of the quality control samples ranged from 103.94 to 105.86% for dipyridamole with overall precision (% C.V.) being 4.60-11.49%. The relative mean recovery of dipyridamole for human serum was 97.64%. Stability studies showed that dipyridamole was stable during storage, or during the assay procedure in human serum. The peak area and retention time of dipyridamole were not significantly affected by the changes of mobile phase pH, organic solvent content, and flow rate under the conditions studied. This method showed good ruggedness (within 15% C.V.) and was successfully used for the analysis of dipyridamole in human serum samples for the pharmacokinetic studies of orally administered Dimor tablet (75 mg as dipyridamole) at three different laboratories, demonstrating the suitability of the method.

• Journal of Pharmaceutical Investigation
• /
• 제36권1호
• /
• pp.23-29
• /
• 2006

A rapid, selective and sensitive reversed-phase HPLC method for the determination of promethazine in human serum was developed, validated, and applied to the pharmacokinetic study of promethazine. Promethazine and internal standard, chlorpromazine, were extracted from human serum by liquid-liquid extraction with n-hexane containing 0.8% isopropanol and analyzed on a Capcell Pak CN column with the mobile phase of acetonitrile-0.2 M potassium dihydrogen phosphate (42:58, v/v, adjusted to pH 6.0 with 1 M NaOH). Detection wavelength of 251 nm and flow rate of 0.9 mL/min were fixed for the study. The assay robustness for the changes of mobile phase pH, organic solvent content, and flow rate was confirmed by $3^{3}$ factorial design using a fixed promethazine concentration (10 ng/mL) with respect to its peak area and retention time. In addition, the ruggedness of this method was investigated at three different laboratories using same quality control (QC) samples. This method showed linear response over the concentration range of 1-40 ng/mL with correlation coefficients greater than 0.999. The lower limit of quantification using 1 mL of serum was 1 ng/mL, which was sensitive enough for pharmacokinetic studies. The overall accuracy of the quality control samples ranged from 96.15 to 105.40% for promethazine with overall precision (% C.V.) being 6.70-11.22%. The relative mean recovery of promethazine for human serum was 63.54%. Stability (freeze-thaw and short-term) studies showed that promethazine was stable during storage, or during the assay procedure in human serum. However, the storage at $-80^{\circ}C$ for 4 weeks showed that promethazine was not stable. Extracted serum sample and stock solution were not allowed to stand at ambient temperature for 12 hr prior to injection. The peak area and retention time of promethazine were not significantly affected by the changes of mobile phase pH, organic solvent content, and flow rate under the conditions studied. This method showed good ruggedness (within 15% C.V.) and was successfully used for the analysis of promethazine in human serum samples for the pharmacokinetic studies of orally administered Himazin tablet (25 mg as promethazine hydrochloride) at three different laboratories, demonstrating the suitability of the method.

• 한국건설관리학회논문집
• /
• 제14권5호
• /
• pp.35-43
• /
• 2013

최근 상당기간과 공사비를 최소화할 수 있는 비정형 건축물의 설계와 시공이 새로운 기술로 구현되고 있다. 이는 비정형 건축물의 최적화 설계와 부재화를 통한 공장 생산 시스템과 현장 조립 및 설치 기술로 가능하다. 비정형 건축물의 구현을 위한 연구가 진행되어 왔으나 여전히 비정형 건축물 시공은 설계오류와 시공자의 도면이해 부족, 시공경험 및 공법의 부재 등으로 인하여 시공 품질과 공기, 공사비 증가 등의 잠재적 리스크를 포함하고 있다. 비정형 건축물의 시공품질 향상과 공기단축 및 시공비 상승의 문제점을 해결하기 위한 3D 디지털 설계와 제작 기술을 적용하는 것이 중요하다. 이에 본 연구는 비정형 구조물의 시공성을 고려한 3차원 디지털 설계 최적화 프로세스를 제안한다. 궁극적으로 본 연구는 비정형 구조물의 구조검토, CNC(Computerized Numerical Control) 가공에 의한 부재의 정밀제작, 설치, 시공의 오차관리로 최적 시공의 근간이 되는 비정형 건축물 외피 시스템 구현을 위한 최적화 설계 프로세스를 제시한다.본 연구는 비정형 건축물을 구현한 사례를 살펴보고 디지털 설계 프로세스와 적용 프로그램을 살펴본다. 비정형 건축물의 설계도의 3D 디지털 데이터 구축과 디지털 최적화 구현 사례로 4대강 대표 물문화관(The ARC)을 중심으로 설계단계에서 적용된 최적화 기법을 순차적으로 분석하여 비정형 건축물의 3차원 좌표제어에 대한 방법론을 제시한다.

• 경영정보학연구
• /
• 제14권3호
• /
• pp.75-97
• /
• 2012

온라인 뱅킹 서비스의 성공을 위해서는 이용 고객의 신뢰를 제고하는 것이 필수적이다. 현재까지 인터넷 뱅킹 이용자들의 신뢰를 제고하는 보안 메커니즘으로 공인인증 서비스가 가장 유력한 대안으로 사용되어 왔다. 그러나 최근 공인인증서를 통한 보안 메커니즘은 해커 등 악의적인 사용자의 침입에 취약할 수 있다는 주장이 제기되고 있다. 본 연구에서는 온라인 뱅킹 보안 메커니즘의 견고성을 높이기 위한 추가적인 대안으로 공인인증서 사용과 관련된 과정의 투명성과 결과 피드백의 투명성이라는 두 가지 요소를 제안하였다. 과정의 투명성은 거래과정에 대한 정보를 이용자에게 제공함으로써 거래 과정을 통제할 수 있도록 하는 것이다. 결과 피드백은 거래결과를 이용자에게 알려줌으로써 이용자가 거래가 의도한 대로 완료되었음을 확인할 수 있도록 하는 것이다. 정보의 투명성에 관한 선행 연구에 따르면, 거래과정과 결과에 대한 정보를 제공하여 투명성을 제고하면 정보시스템 이용자의 의사결정 품질이 제고된다. 거래과정에 대한 정보의 투명성이 확보되면, 정보시스템 이용자들은 거래가 원활하게 수행되고 있는지를 확인할 수 있게 되고, 거래 과정과 결과를 자신이 의도한 대로 통제할 수 있게 되기 때문에, 이용자들의 거래 위험을 감소시킬 수 있다. "구조기반 신뢰" 에 대한 연구에 따르면, 정보시스템 이용자들은 자신들이 성공적으로 거래를 할 수 있도록 구조적인 요소를 제공하는 서비스 제공자들을 보다 신뢰하는 속성이 있다. 거래과정과 거래결과를 확인할 수 있는 정보의 투명성은 정보시스템 이용자가 거래를 원활하게 추진할 수 있는 구조적 기반을 제공하므로 서비스 제공자에 대한 신뢰는 증가하게 된다. 거래 위험이 감소하고 신뢰가 증가되면, 이용자들은 제공되는 서비스에 대해 보다 만족하게 되고, 따라서 서비스 제공자에 대해 충성도가 제고되거나 서비스에 대해 지불 의사를 가지게 될 것이다. 본 연구에서는 실험실 실험을 통해 연구 가설 및 연구 모델을 실증적으로 검증하고자 하였다. 실험설계는 과정의 투명성과 결과의 투명성이라는 두 가지 요인에 따라 $2{\times}2$ 집단으로 구성하여 진행하였다. 공인인증서 사용과 관련된 과정의 투명성과 결과 피드백 요소가 현재 온라인 뱅킹 사이트에서 제공되고 있지 않기 때문에 가상의 온라인 뱅킹 사이트를 구축하여 실험을 진행하였다. 총 138개의 유효한 자료를 실험을 통해 수집하였으며 PLS 알고리즘을 활용하여 분석을 진행하였다. 분석 결과, 과정의 투명성은 온라인 뱅킹 거래의 위험을 줄이고 온라인 뱅킹 사이트에 대한 신뢰를 증가시키는 것으로 나타났다. 결과 피드백은 온라인 뱅킹 사이트에 대한 신뢰를 증가시키는 것으로 나타났다. 이렇게 증가된 신뢰와 감소된 거래위험은 서비스 만족도를 증가시킴으로써 온라인 뱅킹 서비스 이용 고객의 서비스에 대한 지불의도와 온라인 뱅킹 사이트에 대한 충성도를 증가시키는 것으로 조사되었다. 본 연구에서는 온라인 뱅킹 서비스의 보안이라는 주제에 대해 정보의 투명성이 보안에 미치는 영향을 실증자료를 통해 분석함으로써 온라인 보안 메커니즘 연구의 범위를 확대하였을 뿐만 아니라 실제 구현이 가능한 보안 메커니즘에 대한 효과를 검증함으로써 실무적 측면에서의 동헌도가 있다고 판단된다.

• 전자공학회논문지
• /
• 제52권5호
• /
• pp.225-234
• /
• 2015

가상발전소(Virtual Power Plant)는 비상발전(DG), 열병합발전(CHP), 에너지 저장 장치(ESS), 부하(Load)등과 같은 분산 에너지 자원을 ICT기반의 기술로 연계하여 하나의 단일 발전소와 같이 운영하는 기술이다. 지금까지의 가상발전소는 하나의 가상발전 플랫폼을 통하여 광범위하게 산재해 있는 다양한 분산 에너지 자원을 네트워크로 연결하는 구조를 기반으로 개발되고 실증되었다. 그러나 분산 에너지 자원 종류 및 수가 지속적으로 증가할 경우 이러한 분산 에너지 자원과 관련된 데이터 또한 기하급수적으로 증가할 수밖에 없으며 분산 에너지 자원의 분포가 광범위한 지역에 분포되어 있는 경우 하나의 가상발전 플랫폼으로 이들 모든 자원에 대한 네트워크를 중앙 집중형으로 가져가는 것은 네트워크 구성을 위한 기술적, 비용적 측면에서 매우 비효율적이다. 따라서 본 논문에서는 광범위한 지역에 분포되어 있는 분산 에너지 자원을 효율적으로 관리함으로써 시스템 부하에 따른 오류 확률을 낮추고, 분산 에너지 자원과의 데이터 교환의 견고성과 가상발전소의 확장성을 확보할 수 있는 대단위 가상 발전소 구성 방법을 제안한다. 또한 대단위 가상 발전소 구성 시 분산 에너지 자원을 직접적으로 제어하고 모니터링하는 소단위 가상발전 플랫폼에서 가변 및 민감성 부하를 고려한 최적의 자원 스케줄링 방법 또한 시뮬레이션을 통해 그 결과의 유효성을 검증한다.