• Title/Summary/Keyword: Area under the curve (AUC)

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Seasonal Effects Removal of Unsupervised Change Detection based Multitemporal Imagery (다시기 원격탐사자료 기반 무감독 변화탐지의 계절적 영향 제거)

  • Park, Hong Lyun;Choi, Jae Wan;Oh, Jae Hong
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.36 no.2
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    • pp.51-58
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    • 2018
  • Recently, various satellite sensors have been developed and it is becoming more convenient to acquire multitemporal satellite images. Therefore, various researches are being actively carried out in the field of utilizing change detection techniques such as disaster and land monitoring using multitemporal satellite images. In particular, researches related to the development of unsupervised change detection techniques capable of extracting rapidly change regions have been conducted. However, there is a disadvantage that false detection occurs due to a spectral difference such as a seasonal change. In order to overcome the disadvantages, this study aimed to reduce the false alarm detection due to seasonal effects using the direction vector generated by applying the $S^2CVA$ (Sequential Spectral Change Vector Analysis) technique, which is one of the unsupervised change detection methods. $S^2CVA$ technique was applied to RapidEye images of the same and different seasons. We analyzed whether the change direction vector of $S^2CVA$ can remove false positives due to seasonal effects. For the quantitative evaluation, the ROC (Receiver Operating Characteristic) curve and the AUC (Area Under Curve) value were calculated for the change detection results and it was confirmed that the change detection performance was improved compared with the change detection method using only the change magnitude vector.

The Effect of Circadian Rhythm on the Pharmacokinetics of Acebutolol after Intravenous Administration to Rabbits (가토에서 정맥투여시 생체리듬이 아세부토롤의 약물동태에 미친영향)

  • Choi, Jun Shik
    • Korean Journal of Clinical Pharmacy
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    • v.11 no.2
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    • pp.57-61
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    • 2001
  • The effect of circadian rhythm on the pharmacokinetics of acebutolol was studied in rabbits administered intravenous 5 mg/kg dose of acebutolol at 09:00 in the morning (a.m) and 22:00 in the evening (p.m). A significant effect of circadian rhythm of pbarmacokinetic parameters as a function of time of day was noted in rabbits, showing lower total body clearance (CLt), higher plasma concentration and the area under the plasma concentration time curve (AUC) when acebutolol was given in the evening. The plasma concentration of acebutolol was increased significantly (p<0.05) at 12-24 hr after dosing in the evening. The AUC was greater in the evening $(111\%)$ than that in the morning and $CL_t$, was higher when acebutolol was given in the morning ($1.12\pm0.24$ ml/hr) versus in the evening ($1.01\pm0.22$ ml/hr), but those were not significant. Therefore, It is reasonable to consider individual circadian rhythm for effective dosage regimen of acebutolol in clinical chronotherapeutics.

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Feature selection-based Risk Prediction for Hypertension in Korean men (한국 남성의 고혈압에 대한 특징 선택 기반 위험 예측)

  • Dashdondov, Khongorzul;Kim, Mi-Hye
    • Proceedings of the Korea Information Processing Society Conference
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    • 2021.05a
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    • pp.323-325
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    • 2021
  • In this article, we have improved the prediction of hypertension detection using the feature selection method for the Korean national health data named by the KNHANES database. The study identified a variety of risk factors associated with chronic hypertension. The paper is divided into two modules. The first of these is a data pre-processing step that uses a factor analysis (FA) based feature selection method from the dataset. The next module applies a predictive analysis step to detect and predict hypertension risk prediction. In this study, we compare the mean standard error (MSE), F1-score, and area under the ROC curve (AUC) for each classification model. The test results show that the proposed FIFA-OE-NB algorithm has an MSE, F1-score, and AUC outcomes 0.259, 0.460, and 64.70%, respectively. These results demonstrate that the proposed FIFA-OE method outperforms other models for hypertension risk predictions.

A Novel Ocular Delivery System for Phenylephrine Hydrochloride

  • Durrani, A.M.;Jamshaid, M.;Kellaway, I.W.
    • Archives of Pharmacal Research
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    • v.19 no.5
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    • pp.386-389
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    • 1996
  • The in vivo behaviour of phenylephrine hydrochloride in different vehicles like gels of Carbopol $907^circledR$, Carbopol $934P^circledR$ and latex system of cellulose acetate hydrogen phthalate(CAHP) was evaluated by measuring the reduction in intraocular pressure and the mydriatic activity. The parameters that haave been utilised to assess the performance of the formulations were the area under the curve (AUC), the maximum mydriasis $(I_{max})$, ethe time of maximum response $(T_{max})$ and the duration of activity (D). The influence of viscosity and mucoadhesion on the bioavailability parameters has also been investigated. Carbopol 934P and CAHP formulations showed prolonged duration of action and greater AUC compared to Carbopol 907 aqueous solution(P<0.05).

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Use of Artificial Bee Swarm Optimization (ABSO) for Feature Selection in System Diagnosis for Coronary Heart Disease

  • Wiharto;Yaumi A. Z. A. Fajri;Esti Suryani;Sigit Setyawan
    • Journal of information and communication convergence engineering
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    • v.21 no.2
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    • pp.130-138
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    • 2023
  • The selection of the correct examination variables for diagnosing heart disease provides many benefits, including faster diagnosis and lower cost of examination. The selection of inspection variables can be performed by referring to the data of previous examination results so that future investigations can be carried out by referring to these selected variables. This paper proposes a model for selecting examination variables using an Artificial Bee Swarm Optimization method by considering the variables of accuracy and cost of inspection. The proposed feature selection model was evaluated using the performance parameters of accuracy, area under curve (AUC), number of variables, and inspection cost. The test results show that the proposed model can produce 24 examination variables and provide 95.16% accuracy and 97.61% AUC. These results indicate a significant decrease in the number of inspection variables and inspection costs while maintaining performance in the excellent category.

Applying a modified AUC to gene ranking

  • Yu, Wenbao;Chang, Yuan-Chin Ivan;Park, Eunsik
    • Communications for Statistical Applications and Methods
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    • v.25 no.3
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    • pp.307-319
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    • 2018
  • High-throughput technologies enable the simultaneous evaluation of thousands of genes that could discriminate different subclasses of complex diseases. Ranking genes according to differential expression is an important screening step for follow-up analysis. Many statistical measures have been proposed for this purpose. A good ranked list should provide a stable rank (at least for top-ranked gene), and the top ranked genes should have a high power in differentiating different disease status. However, there is a lack of emphasis in the literature on ranking genes based on these two criteria simultaneously. To achieve the above two criteria simultaneously, we proposed to apply a previously reported metric, the modified area under the receiver operating characteristic cure, to gene ranking. The proposed ranking method is found to be promising in leading to a stable ranking list and good prediction performances of top ranked genes. The findings are illustrated through studies on both synthesized data and real microarray gene expression data. The proposed method is recommended for ranking genes or other biomarkers for high-dimensional omics studies.

Preparation and Pharmacokinetic evaluation of Captopril Matrix Tablets with Polyethylene Oxide (폴리에틸렌옥시드를 이용한 캅토프릴 매트릭스 정제의 제조 및 약물동력학적 평가)

  • Jiang, Ge;Baek, Myoung-Ki;Jee, Ung-Kil
    • Journal of Pharmaceutical Investigation
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    • v.29 no.1
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    • pp.7-12
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    • 1999
  • The captopril matrix tablets composed of polyethylene oxide(PEO) was prepared and administered to beagle dogs. Captopril matrix tablets were prepared using direct compressed method and wet granulation compressed method with various ratios of drug to PEO. The diffusion rate of captopril matrix tablets followed on the Higuchi's diffusion model. With increasing hardness of captopril matrix tablets, release rate was decreased. Each formulation was evaluated by the area under the curve (AUC) and time course of plasma captopril concentration after oral administration to beagle dogs. The $AUC_{0-12}$ were $9.126\;{\mu}g\;h/ml$ and $6.417\;{\mu}g\;h/ml$ for the matrix tablets and conventional tablets, respectively. Therefore, the bioavailability of captopril matrix tablets was greater than that of commercial product. It is suggested that captopril matrix tablets using PEO is a useful sustained release formulation.

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Pharmacokinetics of Lithium Carbonate in Rabbits with Experimental Renal Failure (실험적(實驗的) 신장장애(腎臟障害) 가토(家兎)에서 탄산리튬의 약물동태학적(藥物動態學的) 연구(硏究))

  • Burm, Jin-Pil;Kim, Yong-Hyun
    • Journal of Pharmaceutical Investigation
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    • v.15 no.3
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    • pp.113-120
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    • 1985
  • The pharmacokinetics of lithium carbonate were investigated in rabbits with folate-induced renal failure. The blood level, the area under the blood concentration curve (AUC) and the biological half·life were increased significantly, and the urinary excretion was decreased significantly compared with those of normal rabbits. Correlation of serum creatinine concentration and AUC, biological half-life, and correlation of creatinine clearance and renal clearance of lithium carbonate have linear relationship respectively. In short, dosage regimen of lithium carbonate is considered to be adjusted in the dose size and the dosing interval by degree of experimental renal failure.

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Pharmacokinetic Interaction of Vancomycin and Probenecid in Rabbits (반코마이신과 프로베네시드의 약물동태학적 상호작용)

  • Lee, Do-Nil;You, Jae-Sin;Burm, Jin-Pil;Choi, Jun-Shik
    • Journal of Pharmaceutical Investigation
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    • v.27 no.1
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    • pp.51-56
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    • 1997
  • This study was attempted to investigate the pharmacokinetic interaction of vancomycin (10 mg/kg, i.v.) and probenecid (7.5. 15, and 30 mg/kg, oral) in rabbits. The area under curve (AUC) of plasma vancomycin concentration was significantly increased (p<0.01) in rabbits when the probenecid was coadministrated. Volume of distribution (Vd) was significantly decreased (p<0.05) in rabbits coadministrated with probenecid (15 and 30 mg/kg) and total body clearance (CLt) was decreased significantly (p<0.05. p<0.01) in rabbits coadministrated with probenecid (7.5, 15 and 30 mg/kg). There was significant correlation between AUC and probenecid dose. From the results of this experiment, it is desirable to adjust dosage regimen of vancomycin for reduction of side or toxic effect when the probenecid is coadministered in clinical practice.

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Usefulness of four commonly used neuropathic pain screening questionnaires in patients with chronic low back pain: a cross-sectional study

  • Gudala, Kapil;Ghai, Babita;Bansal, Dipika
    • The Korean Journal of Pain
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    • v.30 no.1
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    • pp.51-58
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    • 2017
  • Background: Recently symptoms-based screening questionnaires have gained attention for screening for a neuropathic pain component (NePC) in various chronic pain conditions. The present study assessed the usefulness of four commonly used NePC screening questionnaires including the Self-completed douleur neuropathique 4 (S-DN4), the ID Pain, the painDETECT questionnaire (PDQ), and the Self-completed Leeds Assessment of neuropathic Symptoms and Signs (S-LANSS) questionnaire in patients with chronic low back pain (CLBP) to assess the presence of NePC. Methods: This is a single-center cross-sectional study where patients with CLBP, with or without leg pain, were included. Participants were initially screened for NePC presence by a physician according to the regular practice, and later assessed using screening questionnaires. The diagnostic accuracy of these questionnaires was compared assuming the physician-made diagnosis as the gold standard. Results: A total of 215 patients with CLBP of which 164 (76.3%, 95% CI, 70.2-81.5) had a NePC were included. S-DN4, ID Pain, and PDQ have an area under the curve (AUC) > 0.8 indicating excellent discrimination. However, S-LANSS has an AUC of 0.69 (0.62-0.75), indicating low discrimination. S-DN4 has a significantly higher AUC as compared to ID Pain (d(AUC) = 0.063, P < 0.01) and S-LANSS (d(AUC) = 0.197, P < 0.01). But the AUC of S-DN4 does not significantly differ from that of PDQ (d(AUC) = 0.013, P = 0.62). Conclusions: S-DN4, ID Pain, and PDQ, but not S-LANSS, have good discriminant validity to screen for NePCs in patients with CLBP. Despite using all the tests, 20-30% of patients with an NePC were missed. Thus, these questionnaires can only be used as an initial clue in screening for NePCs, but do not replace clinical judgment.