• The korean journal of orthodontics
• /
• v.25 no.2 s.49
• /
• pp.153-163
• /
• 1995

In this study, Receiver Operating Characteristic(ROC) analysis was used to evaluate the ability of cephalometric measurements to identify patients with Class III malocclusions. ROC analysis is the method for determining the validity of a diagnostic measure and for evaluating the relative value of diagnostic tests. The sample consisted of 496 patients with malocclusion. Class III malocclusion is defined as the dental relationship for which The mesiobuccal groove of the lower first molar is deviated mesially from the mesiobuccal cusp of the upper first molar. Of the total sample of 496 patients, 245 had Class III malocclusions. 16 cephalometric measurements were selected, each of which was treated as a diagnostic test. The ROC curves were generated for each cephalometric measurement with intervals of $1.0^{\circ}$ for angular measurements, 1.0mm for linear measurements. The area under the ROC curves was measured for direct comparison among different diagnostic tests. The results were as follows; 1. The 'Wits' appraisal was found to be a better diagnostic criterion for the presence of Class III malocclusion than any other commonly'used cephalometric measurement. 2. AB plane angle, ANB angle, App-Bpp distance, AF-BF distance, APDI, Distance of point A and Pog to N perpendicular, maxillomandibular differential had high diagnostic value. 3. Cephalometric measurements which evaluate the position of the mandible had moderate diagnostic value. 4. Cephalometric measurements related to the maxilla discriminated least between patients with and without Class III malocclusion.

• Geotechnical Engineering
• /
• v.14 no.2
• /
• pp.41-54
• /
• 1998

Predictions of consolidation settlement and time must be always erroneous because of heterogeneity of soil media. errors associated with the measurement of soil parameters, drawback of consolidation theories and so on. When filling is done on compressible soils, the observational procedure is a useful means in practice of evaluating the final consolidation settlement and time. However, the existing observational procedures including some disadvantages such as the difficulty of ending the linearity in the settlement curves, the unavoidable personal error, and so on. A new observational procedure($\sqrt{s}$ method) is suggested here for the consolidation analysis in field. As the results of applying the $\sqrt{s}$ method with other methods to two field data. the fecal settlements predicted by the s method as well as by the Asaoka'$\sqrt{s}$ method agreed well with the measured values. However, results obtained from the hyperbolic method(Tan, 1991) were always overestimated. and there happened many cases not to be predicted by the Hoshino's method. In the settlement curve from the $\sqrt{s}$method, the linearity between 60 and 90 eye of the average degree of consolidation is shown. and then the possibility of a personal error seems to be unusual. The final consolidation times(at $U_{95}$) predicted by the $\sqrt{s}$ method agreed well with the measured ones. but the ones by Asaoka and Tan(1996) methods were very much underestimated or overestimated. where $U_{95}$, is the average degree of consolidation of 95%. The big errors of these two methods seem to result from unconsidering the effect of stage construction.

• Korean Journal of Poultry Science
• /
• v.9 no.2
• /
• pp.63-101
• /
• 1982

A study was conducted to investigate the possibility of improving the effectiveness of the existing method(s) to estimate the edible meat weight in live broiler chicken. Four. breeds of chicken, white Cornish broiler chicks(parent stock), Single Comb White Leghorn(SCWL) egg strain chicks (parent stock), and two reciprocal cross breds of these parent stocks were employed in this study. A total of 480 birds, 60 male and 60 female chicks for each breed, were used. Ten male and 10 female chicks from each breed were randomly sacrificed at 0, 2, 4, 6, 8 and 10 weeks of ages in order to measure the body weight, edible meat weight of breast and 1eg(thigh and drum-stick), various components of body weight and various body shape measurements. In addition, chemical analyses of edible meat were carried out. Results obtained from this sturd were summarized as follows. 1. The average body weights of White Cornish broiler chicks and SCWL egg strain chicks were 1.82${\pm}$0.048kg(X${\pm}$S.E.) and 0.67${\pm}$0.029 kg. respectively, at 8 weeks of age. The feed to gain ratio for White Cornish and SCWL chicks were 2.24 and 3.28, respectively, for 0 to 8 weeks of age. The reciprocal cross bred chicks (White Cornish ${\times}$ SCWL) showed intermediate values in both parameters.

• Korean Journal of Soil Science and Fertilizer
• /
• v.16 no.4
• /
• pp.301-304
• /
• 1983

Effects of the clay content on soil chemical properties and rice productivity were studied to evaluate the optimum range of clay content from 42 NPK trials conducted by the provincial ORD in 1979. Nutrients content and CEC of the paddy soils were increased with the increase of clay content in paddy soils. Rice yields without NPK application showed a positive linear regression with respect to surface clay content in the paddies, while the relationship between rice yield and clay content with optimun fertilization showed a curvilinear regression, which indicated the maximum yield was observed in loam soils. However, the yield of rice was not significantly different in the range of clay content from 14 to 38%. It implies that the clay content more than 15% may be secondary constraint in determining the soil productivity.

• Analytical Science and Technology
• /
• v.25 no.1
• /
• pp.83-90
• /
• 2012

The objective of the study was to estimate the measurement uncertainty associated with determination of creatinine (Cr) in urine samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Centrifuged urine samples (10 ${\mu}L$) were diluted with 390 ${\mu}L$ of distilled water. To 20 ${\mu}L$ aliquots of diluted urine samples, 30 ${\mu}L$ of internal standard solution (Cr-$d_3$, 5 ${\mu}g/mL$) and 10 ${\mu}L$ of acetonitrile were added and filtered. The samples (1 ${\mu}L$) were introduced into LC-MS/MS with no further pretreatment. Cr was separated on a multi-mode ODS column (Scherzo SM-C18, 75 ${\times}$ 2.0 mm I.D., 3 ${\mu}m$) and quantified by LC-MS/MS operating in MRM mode (Cr, m/z 114.0${\rightarrow}$ 86.0; Cr-$d_3$, m/z 117.0${\rightarrow}$ 89.1). The four factors that contribute uncertainty to the final result were extracted and evaluated. The principal factors of contribution to combined standard uncertainty were sample dilution, calibration curve and repeatability, while the preparation of standard solution was only a minor factor. Relative extended uncertainty of the measured concentration was 14.2% in a real urine sample.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2007.05a
• /
• pp.1214-1218
• /
• 2007

댐 하류로 탁수를 선택적으로 배제하기 위해서는 방류 탁수가 하류에 미치는 영향을 정확히 예측할 수 있는 하천 탁도 예측 및 관리시스템 구축이 필요하다. 낙동강과 반변천의 합류부에서의 이차원적인 혼합에 관한 수치해석 결과는 완전혼합을 가정하는 일차원 수질모델링의 초기 입력자료에 사용됨으로써 낙동강 본류 전체구간의 탁도 모의결과의 정확성을 높이는 데 사용될 수 있다. 본 연구는 낙동강의 중상류에 위치한 반변천 합류부에 평면 이차원 비정상 수치모형인 KU-RLMS 모형을 적용하여 탁도 변화 특성을 규명할 목적으로 수행하였다. KU-RLMS 모형은 하천 및 저수지의 국부적인 수리, 수질, 유사이동 해석을 위해 개발된 평면 이차원 비정상 수치모형이다. 직사각형 격자를 사용하는 유한차분법의 단점을 보완하기 위해, 수심적분된 2차원 연속방정식, 운동량방정식, 이송확산방정식을 불규칙한 경계를 현실적으로 모사할 수 있는 직교곡선 좌표계로 변환한 방정식을 사용한다. 이 모형은 흐름, 농도, 지형변화를 조합하여 계산할 수 있는 모형으로서 점착성 및 비점착성 유사의 이동을 모의할 수 있다. 수치모형 적용을 위한 현황분석으로 안동 및 임하 조정지댐의 방류량, 안동 수위관측소의 수위, 법흥교 및 포진교 지점의 탁도 자료를 분석하였다. 이송확산모형의 보정을 위해, 안동대교 지점의 탁도 횡분포 측정 자료를 사용하여 확산계수에 대한 매개변수 추정 및 검증을 수행하였다. 또한, 안동조정지댐과 임하조정지댐의 방류량 및 방류탁도을 고려하여 수치모의조건을 결정하였으며, 각 조건에 대한 탁도 변화 특성을 분석하였다.된 주변국이 될 수밖에 없을 것이다. 21세기 문화산업에서 우리가 판단하게 될 디자인의 가치는 계몽의 원리에 대한 '역사성'과 '현재성'의 변증법에 달려있는 것이며, 새로운 철학, 새로운 문명, 새로운 세계를 열어가는 것이다.r$ (地理志)에는 추현리와 이미 외리를 언급하면서 상주의 자기제작의 위상을 짐작하는 기록이 언급되면서 전국의 상품의 절반을 담당하고 있었음을 알 수 있었다. $\ulcorner$경상도지리지$\lrcorner$(慶尙道地理志)에는 상주가 8곳으로 1/3의 자기 생산을 담당하고 있었다. $\ulcorner$경상도지리지$\lrcorner$(慶尙道地理志)에는 $\ulcorner$세종실록$\lrcorner$(世宗實錄) $\ulcorner$지리지$\lrcorner$(地理志)와 동년대에 동일한 목적으로 찬술되었음을 알 수 있다. $\ulcorner$경상도실록지리지$\lrcorner$(慶尙道實錄地理志)에는 $\ulcorner$세종실록$\lrcorner$(世宗實錄) $\ulcorner$지리지$\lrcorner$(地理志)와의 비교를 해보면 상 중 하품의 통합 9개소가 삭제되어 있고, $\ulcorner$동국여지승람$\lrcorner$(東國與地勝覽) 에서는 자기소와 도기

• Analytical Science and Technology
• /
• v.24 no.1
• /
• pp.1-9
• /
• 2011

We described an estimation of measurement uncertainty in quantitative analysis of 11-nor-9-carboxy-${\Delta}^9$-tetrahydrocannabinol (THC-COOH), the metabolite of ${\Delta}^9$-tetrahydrocannabinol, in hair samples by using the bead-assisted liquid-liquid extraction and gas chromatography-tandem mass spectrometric (GC-NCI-MS/MS) detection. Traceability of measurement was established through the use of reference materials, calibrated volumetric tubes, volume measuring devices, and measuring instruments. The analytical results were compared and the different contributions to the uncertainty were evaluated. Inter-day variation was performed by using statistical analysis of several indicative factors. Measurement uncertainty associated with the analyte in real forensic hair samples were estimated using QC data. The major factor of contribution to combined standard uncertainty was inter-day repeatability, while those associated with preparation of analytical standard and also sample of weight were insignificant considering the degree of contribution. Relative uncertainty of relative extended standard uncertainty divided into the measured concentration of the analyte was 17% in a hair sample. The uncertainty of result evaluation will be invaluable to improve quality of the analysis.

• Economic and Environmental Geology
• /
• v.38 no.1
• /
• pp.45-55
• /
• 2005

Traditional GIS-based probabilistic spatial data integration models for landslide susceptibility analysis have failed to provide the theoretical backgrounds and effective methods for integration of different types of spatial data such as categorical and continuous data. This paper applies two spatial data integration models including non-parametric empirical estimation and parametric predictive discriminant analysis models that can directly use the original continuous data within a likelihood ratio framework. Similarity rates and a prediction rate curve are computed to quantitatively compare those two models. To illustrate the proposed models, two case studies from the Jangheung and Boeun areas were carried out and analyzed. As a result of the Jangheung case study, two models showed similar prediction capabilities. On the other hand, in the Boeun area, the parametric predictive discriminant analysis model showed the better prediction capability than that from the non-parametric empirical estimation model. In conclusion, the proposed models could effectively integrate the continuous data for landslide susceptibility analysis and more case studies should be carried out to support the results from the case studies, since each model has a distinctive feature in continuous data representation.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.993-999
• /
• 2008

A girder height limitation is the critical parameter for rapid construction of bridge deck and construction space limitation especially in urban area such as high population area and high density habitats. A standard post-tensioned I-shaped concrete girder usually demands relatively higher girder height in order to retain sufficient moment arm between compression force and tensile force. To elaborate this issue, a small U-shaped section with wide flanges can be used as a possible replacement of I-shaped standard girder. This prestressed concrete box girder allows more flexible girder height adjustment rather than standard I-shaped post-tensioned girder plus additional torsion resistance benefits of closed section. A 30m-long, 1.7m-high and 3.63m-wide actual small prestressed concrete box girder is designed and a laboratory test for its static behaviors by applying 6,200kN amount of load in the form of 4-point bending test was performed. The load-deflection curve and crack patterns at different loading stage are recorded. In addition, to extracting the dynamic characteristics such as natural frequency and damping ratio of this girder, several excitation tests with artificial mechanical exciter with un-symmetric mass are carried out using operational frequency sweep-up. Nonlinear finite element analysis of this 4 point bending test under monotonic static load is investigated and discussed with aids of concrete damaged plasticity formulation using ABAQUS program.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.23 no.5
• /
• pp.84-95
• /
• 2019

This paper reports the process of seismic fragility analysis for the rahman-type continuous bridge system. The target structure was the five span highway bridge with maximum pier hight of 72m. OpenSees software was used for the nonlinear time history analysis. In this study, 50 ground motions are considered for nonlinear time history analysis. For each ground motion, PGA was scaled from 0.1g to 2.0g with intervals of 0.1g in order to consider a wide range of the seismic intensity measure. In addition, yield displacement and ultimate displacement of each pier were calculated through section analysis. Based on the result of non linear time history analysis and section analysis, damage condition of target bridge was classified according to the definition of damage condition proposed by Barbat et al. As a result, it was predicted that Extensive Damage occurred at P1 when 0.731 g earthquake occurred in the longitudinal direction. Based on the seismic fragility analysis results, it is found that the probability of occurrence of Extensive Damage in the 4,800 - year period earthquake was about 4.2%. Therefore the target bridge has enough safety for earthquake.