• Title/Summary/Keyword: Over-Sampling

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A High-resolution Numerical Simulation and Evaluation of Oak Pollen Dispersion Using the CMAQ-pollen Model (CMAQ-pollen 모델을 이용한 참나무 꽃가루 확산 고해상도 수치모의 및 검증)

  • Oh, Inbo;Kim, Kyu Rang;Bang, Jin-Hee;Lim, Yun-Kyu;Cho, Changbum;Oh, Jae-Won;Kim, Yangho;Hwang, Mi-Kyoung
    • Journal of Korean Society for Atmospheric Environment
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    • v.33 no.1
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    • pp.31-44
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    • 2017
  • The aim of this study is to evaluate the accuracy and variability of the oak pollen concentrations over the Seoul metropolitan region (SMR) simulated by the Community Multiscale Air Quality (CMAQ)-based pollen dispersion model, which is the CMAQ-pollen model integrated with the improved oak pollen emission model(PEM-oak). The PEM-oak model developed is based on hourly emission flux parameterization that includes the effects of plant-specific release, meteorological adjustment, and diurnal variations of oak pollen concentrations. A 33 day-run for oak pollen simulation was conducted by the CMAQ-pollen model with a 3 km spatial resolution for the SMR during the 2014 spring pollen season. Modeled concentrations were evaluated against the hourly measurements at three Burkard sampling sites. Temporal variations of oak concentrations were largely well represented by the model, but the quantitative difference between simulations and measurements was found to be significant in some periods. The model results also showed that large variations in oak pollen concentrations existed in time and space and high concentrations in the SMR were closely associated with the regional transport under strong wind condition. This study showed the effective application of the CMAQ-pollen modeling system to simulate oak pollen concentration in the SMR. Our results could be helpful in providing information on allergenic pollen exposure. Further efforts are needed to further understand the oak pollen release characteristics such as interannual variation of the oak pollen productivity and its spatio-temporal flowering timing.

Bioequivalence of Two Nilvadipine Tablet (닐바디핀 정제에 대한 생물학적 동등성 평가)

  • 김종국;이사원;최한곤;고종호;이미경;김인숙
    • Biomolecules & Therapeutics
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    • v.6 no.3
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    • pp.289-295
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    • 1998
  • The bioequivalence of two nilvadipine products was evaluated in 16 normal male volunteers (age 22-32 yr, body weight 57-80 kg) following sidle oral dose. Test product was Overca $l_{R}$ tablet (Choong-Wae Pharm. Corp., Korea) and reference product was Nivadi $l_{R}$ tablet (Hyundai Pharm. Corp., Korea). Both products contain 4 mg of nilvadipine. One tablet of the test or the reference product was administered to the volunteers, respectively, by randomized two period cross-over study (2$\times$2 Latin square method). The determination of nilvadipine was accomplished using a validated capillary column GC with electron-capture detection. As a result of the assay validation, the quantiflcation of nilvadipine in human plasma by this technique was possible down to 0.5 ng/ml using 1 ml of plasma. Absolute overall recovery from five replicate analyses of nilvadipine-spiked sample were 88.4$\pm$ 10.24% (mean$\pm$ 5.D.) for human plasma of 10 ng/ml. The coefficients of variation (C.V.) were less than 20% and the actual concentration of nilvadipine measured by GC ranged from 80 to 99% in all plasma. Average drug concentrations at each sampling time and pharmacokinetic parameters calculated were not significantly different between two products (p>0.05); the area under the curve from time zero to 8 hr (AUCo-$_{8 hr}$) (22.8$\pm$5.90 vs 22.2$\pm$6.10 ng . hr/ml), maximum plasma concentration ( $C_{max}$) (10.0$\pm$2.85 vs 9.3$\pm$3.28 ng/ml) and time to reach maximum plasma concentration ( $T_{max}$) (1.2$\pm$0.31 vs 1.3 $\pm$0.47 hr). The differences of mean AU $Co_{8hr}$ $C_{max}$, and $T_{max}$ between the two products (2.25, 7.65, and 10.30%, respectively) were less than 20%. The power (1-$\beta$) and treaeent difference (7) for AU $Co_{8hr}$, and $C_{max}$ were more than 0.8 and less than 0.2, respectively. Although the power for Tmax was under 0.8, Tm\ulcorner of the two products was not significantly different from each other (p>0. 05). These results suggest that the bioavailability of Overeat tablet is not significantly different from that of Nivadil tablet. Therefore, two products are bioequivalent based on the current results.sults.lts.lts.lts.

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A Nationwide Survey on the Prevalence of Intestinal Parasitic Infections in the Republic of Korea, 2004

  • Kim, Tong-Soo;Cho, Shin-Hyeong;Huh, Sun;Kong, Yoon;Sohn, Woon-Mok;Hwang, Seung-Sik;Chai, Jong-Yil;Lee, Soon-Hyung;Park, Yun-Kyu;Oh, Dae-Kyu;Lee, Jong-Koo;Working Groups in National Institute of Health, Working Groups in National Institute of Health;Korea Association of Health Promotion, Korea Association of Health Promotion
    • Parasites, Hosts and Diseases
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    • v.47 no.1
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    • pp.37-47
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    • 2009
  • National surveys on the prevalence of intestinal parasitic infections have been carried out every 5-7 years since 1971 in the Republic of Korea in order to establish control measures. The present nationwide survey was conducted from June to December 2004. The 10% population sampling data of Population and Housing Census by the Korean government in 2000 was used as the survey population. One sample was selected randomly from each of the 22,858 registered subjects, and a total of 20,541 people were ultimately included in this survey. Fecal examinations were performed by the cellophane thick smear and saturated brine flotation techniques. Pinworm infection was examined by cello-tape anal swab method. This survey also included a questionnaire study for a socioeconomic analysis. The total helminth egg positive rate was 3.7%, and the estimated total positive number among nationwide people was 1,780,000. The rates in urban and rural areas were 3.1% and 6.8%, respectively. As the total egg positive rate in the 6th survey in 1997 was 2.4%, the present survey showed that there was a considerable degree of increase in the prevalence rate of intestinal parasitic infections over the 7-year period following the 6th survey. The largest increases occurred in the egg positive rates of Clonorchis sinensis and heterophyids including Metagonimus yokogawai.

Epidemiologic Study of Clonorchis Sinensis Infestation in a Rural Area of Kyongsangnam-do, South Korea (경상남도 일부 농촌지역의 간흡충 감염에 대한 역학적 연구)

  • Ju, Young-Hee;Oh, Jin-Kyoung;Kong, Hyun-Joo;Sohn, Woon-Mok;Kim, Yoon-Gyu;Kim, Jung-Il;Jung, Kap-Yeol;Shin, Hai-Rim
    • Journal of Preventive Medicine and Public Health
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    • v.38 no.4
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    • pp.425-430
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    • 2005
  • Objectives : To investigate the prevalence of Clonorchis Sinensis infestation and to determine the associated risk factors among a population in a part of the rural area of Gyeongsangnam-do, Korea, which is an area known to have a high mortality from liver cancer and a high infection of C. sinensis. Methods : The study populat ion consisted of those people who have lived in rural areas and who were over 40 years old. This study was performed in 5 areas during the period from 1999 to 200 3. Informed consents were obtained from the 2,381 study participants, and these people were interviewed about their life style habits with using the structured questionnaire that was administered by trained staff members. The subjects underwent blood sampling and their stool specimens were examined by using the Formalin-ether sedimentation technique. Results : Among the study subjects (N=2,381), the positivity for C. sinensis in the stool was 34.4% (95% CI=36.3-42.5); it was 39.4% (95% CI=36.3-42.5) in the males and 30.9% (95% CI=28.5-33.3) in the females . The positivity for C. sinensis was associated with current alcohol drinking (odds ratio=1.8, 95% CI: 1.5-2.1) and raw fish consumption (odds ratio 1.2, 95% CI: 0.9-1.6). Conclusion : The present study confirmed the high prevalence of C. sinensis in the study subjects. It is necessary to establish consistent medical management and education programs for the treatment and prevention of C. sinensis infestation in the rural inhabitants of Korea.

Development of Prediction Model of Financial Distress and Improvement of Prediction Performance Using Data Mining Techniques (데이터마이닝 기법을 이용한 기업부실화 예측 모델 개발과 예측 성능 향상에 관한 연구)

  • Kim, Raynghyung;Yoo, Donghee;Kim, Gunwoo
    • Information Systems Review
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    • v.18 no.2
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    • pp.173-198
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    • 2016
  • Financial distress can damage stakeholders and even lead to significant social costs. Thus, financial distress prediction is an important issue in macroeconomics. However, most existing studies on building a financial distress prediction model have only considered idiosyncratic risk factors without considering systematic risk factors. In this study, we propose a prediction model that considers both the idiosyncratic risk based on a financial ratio and the systematic risk based on a business cycle. Ultimately, we build several IT artifacts associated with financial ratio and add them to the idiosyncratic risk factors as well as address the imbalanced data problem by using an oversampling technique and synthetic minority oversampling technique (SMOTE) to ensure good performance. When considering systematic risk, our study ensures that each data set consists of both financially distressed companies and financially sound companies in each business cycle phase. We conducted several experiments that change the initial imbalanced sample ratio between the two company groups into a 1:1 sample ratio using SMOTE and compared the prediction results from the individual data set. We also predicted data sets from the subsequent business cycle phase as a test set through a built prediction model that used business contraction phase data sets, and then we compared previous prediction performance and subsequent prediction performance. Thus, our findings can provide insights into making rational decisions for stakeholders that are experiencing an economic crisis.

Study of Particle Emission Contour Construction & Characteristics and Reduction Efficiency of Exhaust-Treatment System of Diesel Engine (승용 디젤 엔진의 후처리 시스템 적용에 따른 나노입자 배출 맵 구축 및 저감특성에 관한 연구)

  • Ko, A-Hyun;Hwang, In-Goo;Myung, Cha-Lee;Park, Sim-Soo;Choi, Hoi-Myung
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.34 no.8
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    • pp.755-760
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    • 2010
  • In this study, we mainly focused on the PM (Particulate Matter) emission characteristics of a diesel engine. To analyze particle behavior in the tail-pipe, particle emission was measured on the engine-out (downstream of turbocharger), each upstream and downstream both of DOC (Diesel Oxidation Catalyst) and DPF (Diesel Particulate Filter). Moreover, particle emission contours on each sampling point were constructed. The reduction efficiency of particle number concentration and mass through the DOC and DPF was studied. Parameters such as EGR (Exhaust Gas Recirculation) and the main injection timing were varied in part load conditions and evaluated using the engine-out emissions. The DMS500 (Differential Mobility Spectrometer) was used as a particle measurement instrument that can measure particle concentrations from 5 nm to 1000 nm. Nano-particles of sizes less than 30 nm were reduced by oxidation or coagulated with solid particles in the tail-pipe and DOC. The DPF has a very high filtration efficiency over all operating conditions except during natural regeneration of DPF.

Analysis of Burn Severity in Large-fire Area Using SPOT5 Images and Field Survey Data (SPOT5영상과 현장조사자료를 융합한 대형산불지역의 피해강도 분석)

  • Won, Myoungsoo;Kim, Kyongha;Lee, Sangwoo
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.16 no.2
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    • pp.114-124
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    • 2014
  • For classifying fire damaged areas and analyzing burn severity of two large-fire areas damaged over 100 ha in 2011, three methods were employed utilized supervised classification, unsupervised classification and Normalized Difference Vegetation Index (NDVI). In this paper, the post-fire imageries of SPOT were used to compute the Maximum Likelihood (MLC), Minimum Distance (MIN), ISODATA, K-means, NDVI and to evaluate large-scale patterns of burn severity from 1 m to 5 m spatial resolutions. The result of the accuracy verification on burn severity from satellite images showed that average overall accuracy was 88.38 % and the Kappa coefficient was 0.8147. To compare the accuracy between burn severity and field survey at Uljin and Youngduk, two large fire sites were selected as study areas, and forty-four sampling plots were assigned in each study area for field survey. The burn severities of the study areas were estimated by analyzing burn severity (BS) classes from SPOT images taken one month after the occurrence of the fire. The applicability of composite burn index (CBI) was validated with a correlation analysis between field survey data and burn severity classified by SPOT5, and by their confusion matrix. The result showed that correlation between field survey data and BS by SPOT5 were closely correlated in both Uljin (r = -0.544 and p<0.01) and Youngduk (r = -0.616 and p<0.01). Thus, this result supported that the proposed burn severity analysis is an adequate method to measure burn severity of large fire areas in Korea.

Hematuria among Benzidine Dye Industry Workers (벤지딘 염료공장 노동자들의 혈뇨)

  • Son, Mi-A.;Paek, Do-Myung;Choi, Jung-Kun;Park, Su-Kyeong;Park, Jung-Soon;Oh, Se-Min;Park, Jung-Sun;Park, Dong-Ook
    • Journal of Preventive Medicine and Public Health
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    • v.28 no.1 s.49
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    • pp.225-243
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    • 1995
  • Benzidine Industry in Korea has started after Japan has banned its production in early 1970's, and it has been in operation in Korea for over 20 years. However, it is not known yet whether any bladder cancer has developed from benzidine exposure. This study was done to screen benzidine-exposed workers for bladder cancer, and to examine the feasibility of employing screening test at the workplace. All the workplaces that manufacture or use benzidine for more than 20 years in Korea have been covered in this study, and they include 2 benzidine manufacturing factories, 5 benzidine using factories, as well as 2 benzidine free factories as an outside control. In total, 516 workers were screened with urine stick test and urine cytology test for the evidence of hematuria and abnormal urothelial cells. Each worker was also asked about risk factors and symptoms of bladder cancer including past medical history, smoking, medication and occupational history Benzidine in the air was measured by personal and area sampling. Out of 516 screened workers, 84(16.3%) workers showed positive hematuria in urine stick test, and 7(1.4%) workers showed degenerative cells in urine cytology tests. Those workers with abnormal urine test results who have been exposed to benzidine fo more than 10 years were further screened, and, in total, 23 workers were examined with intra-venous pyelography and cystoscopy. None of those screened had any evidence of bladder cancer When workers with only past hematuria history were included in the positive hematuria group, 96(18.5%) had positive hematuria. On the multiple logistic regression analysis, positive hematuria was significantly associated with benzidine exposure, history of other occupations with elevated bladder cancer risk, pyuria and glycosuria. The association got stronger as direct benzidine exposure was accounted through individual task analysis, and as exposure duration was accounted with tenure analysis. For those with benzidine exposure with more than 10 years of tenure, the odds of having positive hematuria was elevated 2.14(95%C.I is 1.08 to 4.25) times more than for those without exposure. Even though bladder cancer was not detected for several limitations including short observation period, majority of studied workers with short latency, healthy worker effect, and low sensitivity of single screening test in a cross-sectional study, the study results suggest that hematuria screening is a feasible and very useful test for bladder cancer screening among benzidine exposed workers.

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Effect on Body Guards Task Stress has in ferment of enzyme (경호원의 직무스트레스가 항산화효소에 미치는 영향)

  • Roh, Sun-Pyo
    • Korean Security Journal
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    • no.18
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    • pp.21-37
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    • 2009
  • The purpose of study were the effect of stress levels and duty type of guarder on 8-OHdG(hydroxydeoxyguanosin), Immunoglobin, T-cell, NK-cell and antioxidant enzyme. The subject of this study is people who have the guard's career over 2 years. A group of object sample consists of sixty guards carrying the guardbusiness. The group division and distribution of the number of persons a group divided into the guard group of international factor(N=23), private guard group(N=23),and the others(N=14) as a group following the guardbusiness. The group following a stress level divided into 3groups as their score of stress measure; low stress group(N=14), middle stress group(N=26),and high stress group(N=20). In the office type, the experiment sampling the blood, analysing result of following the office type and stress had a conclusion after measuring stress as the followings. The stress level in the office type of guard showed highly in the guard group of international factor(p<.05). Finally we knew that the guard have different stress levels in the office type, even the immune function and the activation of superoxide dismutase affected them in the stress level. Stress showing in the guard career can do them an injury so it is desirable for the guard themselves to participate in the activities settling their stresses and in the development of exercise programs.

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Identification of Factors Affecting Errors of Velocity Calculation on Application of MLSPIV and Analysys of its Errors through Labortory Experiment (MLSPIV를 이용한 유속산정시 오차요인 규명 및 실내실험을 통한 유속산정오차 분석)

  • Kim, Young-Sung;Lee, Hyun-Seok
    • Journal of Korea Water Resources Association
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    • v.43 no.2
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    • pp.153-165
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    • 2010
  • Large-Scale Particle Image Velocimetry (LSPIV) is an extension of particle image velocimetry (PIV) for measurement of flows spanning large areas in laboratory or field conditions. LSPIV is composed of six elements - seeding, illumination, recording, image transformation, image processing, postprocessing - based on PIV. Possible error elements at each step of Mobile LSPIV (MLSPIV), which is a mobile version of LSPIV, in field applications are identified and summarized the effect of the errors which were quantified in the previous studies. The total number of elemental errors is 27, and five error sources were evaluated previously, seven elemental errors are not effective to the current MLSPIV system. Among 15 elemental errors, four errors - sampling time, image resolution, tracer, and wind - are investigated through an experiment at a laboratory to figure out how those errors affect to velocity calculation. The analysis to figure out the effect of the number of images used for image processing on the velocity calculation error shows that if over 50 images or more are used, the error due to it goes below 1 %. The effect of the image resolution on velocity calculation was investigated through various image resolution using digital camera. Low resolution image set made 3 % of velocity calculation error comparing with high resolution image set as a reference. For the effect of tracers and wind, the wind effect on tracer is decreasing remarkably with increasing the flume bulk velocity. To minimize the velocity evaluation error due to wind, tracers with high specific gravity is favorable.