• 한국학교보건학회지
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• 제1권1호
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• pp.148-159
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• 1988

For the evaluation of physical assessment by school nurses, this study was designed in two steps physical assessment. The first step is the primary health screening by school health nurses. The second step is the Physicians' physical examination of ill health students selected by school nurses. This study was conducted on a total of 3,525 students of three primary schools located in urban, township, and rural area during the period from May to June, 1987, all data were collected through direct observation & survey method. The main findings are as follows 1. The number of ill health students selected by two step method was more than that of one step method by the physician. 2. The types of ill health students selected by two step method had more diversity than that of one step method by the physician. 3. Budgets and time consumption for two step method were more reductive than that of one step method by the physician.

• 생명과학회지
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• 제31권4호
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• pp.385-388
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• 2021

벼 육종을 위한 약 배양은 기존 육종 방법을 사용하여 새로운 품종을 개발하는데 최소 6세대에 필요한 시간을 크게 줄여 동형접합자를 신속하게 생산하는 방법이다. 이 약 배양기술은 방법론적 관점에서 더 많은 녹색 식물을 얻을 기회를 제공하며, 약 배양에서 시간과 노력을 절약하는 배양의 효율성을 높이기 때문에 중요하다. 본 연구에서는 배양액과 배양 방법이 다른 1단계와 2 단계 배양의 캘러스 유도율과 녹색 식물 재분화율로 비교하였다. 1단계 배양은 하나의 배지에서 캘러스 유도 및 식물 재생을 허용하는 반면, 2 단계 배양은 두 개의 다른 배지에서 유도 및 식물 재분화가 필요하다. 이 연구에서는 1 단계 및 2 단계 배양으로 벼 꽃밥의 캘러스 유도와 식물 재생률을 비교했다. 캘러스 형성률은 1 단계 배양의 경우 13.0 %, 2 단계 배양의 경우 8.6%로 2 단계 배양보다 1 단계 배양에서 4.4% 더 높았다. 식물 재분화율은 1 단계 배양에서 1.0%, 2 단계 배양에서 3.0 %로 1 단계 배양보다 2단계 배양에서 식물체 재분화율이 3배 더 높았다. 이것은 2 단계 배양이 반수체 생산을 위한 1 단계 배양보다 더 효율적임을 시사한다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 제5회 박판성형 SYMPOSIUM
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• pp.49-54
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• 2006

During most of manufacturing processes of auto-body panels, the trimming line should be designed in advance prior to flanging. It is an important task to find a feasible trimming line to obtain a precise final part shape after flanging. This paper proposes a new fast method to find feasible trimming line based on one-step analysis. The basic idea of the one-step analysis is to seek for the nodal positions in the initial blank from the final part, and then the distribution of strain, stress and thickness in the final configuration can be calculated by comparing the nodal position in the initial blank sheet with the one of the final part. The one-step analysis method is able to predict the trimming line before flanging since the desired product shape after flanging can be defined from the final configuration and most of strain paths are simple during the flanging process. Finally, designers can obtain a discrete trimming line from the boundary of the developed meshes after one-step analysis and import it into CAD system in the early design stage. The proposed method has been successfully applied to two basic curve flanging processes demonstrating many advantages.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.240-247
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• 2006

Piezoelectric sensor-based health monitoring technique using a two-step support vector machine (SYM) classifier is discussed for damage identification of a railroad track. An active sensing system composed of two PZT patches was investigated in conjunction with both impedance and guided wave propagation methods to detect two kinds of damage of the railroad track (one is a hole damage of 0.5cm in diameter at web section and the other is a transverse cut damage of 7.5cm in length and 0.5cm in depth at head section). Two damage-sensitive features were extracted one by one from each method; a) feature I: root mean square deviations (RMSD) of impedance signatures and b) feature II: wavelet coefficients for $A_0$ mode of guided waves. By defining damage indices from those damage-sensitive features, a two-dimensional damage feature (2-D DF) space was made. In order to minimize a false-positive indication of the current active sensing system, a two-step SYM classifier was applied to the 2-D DF space. As a result, optimal separable hyper-planes were successfully established by the two-step SYM classifier: Damage detection was accomplished by the first step-SYM, and damage classification was also carried out by the second step-SYM. Finally, the applicability of the proposed two-step SYM classifier has been verified by thirty test patterns.

• 전기학회논문지
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• 제56권3호
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• pp.465-471
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• 2007

The one step type pole and two step type pole are used in KEPCO's distribution system. The neutral current increases in three-phase four-wire distribution system due to unbalanced load. Usually, power line and communication line are installed at contiguity by effect of topography in Korea. To this end, the damages such as electrostatic induction, electromagnetic induction and harmonic induction generated by induced voltage and current are occured in power line and communication line. This paper calculates the neutral current in KEPCO's distribution system using EMTP by composing various simulated conditions. Also, these results are verified by vector analysis.

• 한국수자원학회논문집
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• 제44권4호
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• pp.275-283
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• 2011

미래 기온변화 정보를 제공하는 General Circulation Model (GCM) 자료, 즉 광역 기온자료를 이용하여 우리나라의 국지 수온변화를 추정하는 연구를 수행하였다. 국지수온 추정은 마산만, 시화호, 낙동강 하구를 대상으로 Two-step 접근방법과 One-step 접근방법을 적용하여 각각의 추정오차를 비교 분석하였다. Two-step 추정방법은 광역 기온으로 국지기온을 추정하는 제1단계에서는 선형회귀분석 기법을 적용하였으며, 모든 지점에서 결정계수가 0.98~0.99 정도로 매우 높게 나타났다. 그리고 국지기온으로 국지수온을 추정하는 제2단계에서는 S-형태함수의 비선형 회귀분석기법을 적용하였으며 이 경우 RMS(Root-mean squared) 오차는 마산만에서 2.07 (온도 증가시기), 1.93 (온도 감소시기), 시화호에서는 2.59, 낙동강 하구에서는 1.58로 파악되었다. 반면 동일한 S-형태함수를 이용한 비선형 회귀분석기법으로 광역기온자료로부터 바로 국지 수온을 추정하는 One-step 접근방법을 적용한 경우, RMS 오차는 마산만이 2.28 (온도증가시기), 1.89 (온도감소시기), 시화호에서는 2.55, 낙동강하구는 1.52로 Two-step 접근방법과 비슷한 수준의 오차를 보이는 것으로 파악되었다. 따라서 광역 기온자료를 이용하여 국지 수온을 추정하는 경우에는 One-step 접근방법도 유용하고 실용적인 것으로 판단된다.

• 한국세라믹학회지
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• 제50권1호
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• pp.70-74
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• 2013

Dependence of microwave dielectric properties on the crystallization behaviors of $CaMgSi_2O_6$ (diopside) glass-ceramics was investigated with different heat treatment methods (one and/or two-step). The crystallization behaviors of the specimens, crystallite size and degree of crystallization, were evaluated by differential thermal analysis (DTA), scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis by combined Rietveld and reference intensity ratio (RIR) methods. With an increase in heattreatment temperature, the dielectric constant (K) and the quality factor (Qf) increased due to the increase of the crystallite size and degree of crystallization. The specimens heat-treated by the two-step method had a higher degree of crystallization than the specimens heat-treated by the one-step method, which induced improvement in the quality factor (Qf) of the specimens.

• 대한치과보철학회지
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• 제48권4호
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• pp.243-250
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• 2010

연구 목적: 본 연구는 잘 맞는 임플란트 상부구조물에서 서로 다른 나사조임순서와 조임방법이 나사의 풀림토크값에 미치는 영향을 평가하였다. 연구 재료 및 방법: 서로 수동적 적합 관계를 갖는 완전 무치악 하악 주모형과 네 개의 평행한 임플란트 (Astra Tech)에 직접 연결되는 금속구조물을 제작하였다. 금속구조물과 잘 맞는 실험모형을 위해 주모형에서 연결인상법을 이용하여 여섯 개의 경석고 모형을 얻었다. 20 Ncm로 조인 후 나사의 풀림토크값을 두 번 측정하였다. 세 가지 나사조임순서 (1-2-3-4, 2-4-3-1, 그리고 2-3-1-4)와 두 가지 나사조임방법 (two-step과 one-step)에 대한 나사의 풀림토크값과 최소풀림토크값을 유의수준 .05에서 각각 다원분산분석법 (multi-way ANOVA)과 이원분산분석법 (two-way ANOVA)을 이용하여 통계분석 하였다. 결과: 나사조임순서에 대한 나사의 평균 풀림토크값은 12.8 Ncm (2-4-3-1)에서 13.1 Ncm (2-3-1-4)의 값을 보였고, 나사조임방법에 대한 값은 13.1 Ncm (two-step)와 11.8 Ncm (one-step)였다. 나사조임순서에 대한 나사의 평균 최소풀림토크값은 11.1 Ncm (1-2-3-4)와 11.2 Ncm (2-4-3-1과 2-3-1-4)였고, 나사조임방법에 대한 값은 11.2 Ncm (two-step)와 9.9 Ncm (one-step)였다. 나사의 풀림토크값과 최소풀림토크값은 세 가지 나사조임순서 간에 통계학적으로 유의성 있는 차이가 없었다. 그러나 두 가지 나사조임방법 간에는 두 값 모두 통계학적으로 유의성 있는 차이가 있었다. 나사를 두 단계로 나누어 조이는 방법이 한 번에 조이는 방법보다 더 큰 풀림토크값 (P = .0003)과 더 큰 최소풀림토크 값 (P = .0035)을 보였다. 결론: 본 연구와 같은 조건하에서, 연결인상법으로 얻은 잘 맞는 임플란트 상부구조물에 있어서 나사조임순서는 나사의 풀림토크값에 영향을 미치는 중요한 요소는 아니었다. 그러나 나사를 두 단계로 나누어 조이는 방법은 한 번에 조이는 방법보다 더 큰 풀림토크값을 보였다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 춘계학술대회 논문집
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• pp.154-160
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• 1998

This study describes a theoretical and experimental investigation of gas wave propagation in the pipe system. Most calculations of compressible flows in the pipe have been based on the method of characteristics. This technique has propensity to truncate waves and is difficult to apply to non-perfect gas. A method that describes the application of a two-step Lax-Wendroff acheme to solution of the unsteady one-dimentional flow in the pipe was developed. Theoretical calculations using both the method of characteristics and the two-step Lax-Wendroff method are presented including a realistic model for heat transfer and friction processes. In the present work, account is taken of the nonlinear behavior. For sections of parallel pipe, an one dimensional unsteady homentropic analysis is employed, and a numerical solution is obtained with the aid of a digital computer, using the method of characteristics and two-step Lax-Wendroff method. This analysis is then combined with boundary models, based on a quasi-steady flow approach, to give a complete treatment of the flow behavior in the pipe system.

• 핵의학기술
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• 제28권1호
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• pp.81-87
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• 2024

Purpose: CA 19-9 is the most widely used tumor marker for the diagnosis of digestive system tumor, especially pancreatic and biliary tract cancer. This study was conducted to improve the result value near reference range by comparing the reagents of CA 19-9 one step method and two step method. In addition, it was intended to establish a standard for selecting reagents. Material and Methods: 120 patients who visited the National Cancer Center in 2023 were selected as subjects for this study. The reagents used in the study were CA 19-9 IRMA kits (Shinjin, Korea) and three types of reagents were compared. Two step method reagent that is currently being used (A), one step method reagent (B) and two step method reagent improved by request (C) were compared and regression analysis was performed on their data. And we also performed recovery test, linearity test and hook effect test for each reagent. Result: There were 46 cases of reagent B in which the concentration value was lower than the result measured in reagent A that was previously used, and 77 cases of reagent C. As a result of regression analysis of reagents A, B, and C, the coefficients of determination of reagents A and B, reagents A and C, and reagents B and C were 0.653, 0.577, and 0.875. In the recovery rate test and the linearity test, the results of all reagents were good, and in the hook effect test, reagent B showed a hook effect at a low value. Conclusion: The improved reagent C appears to have been improved based on the concentration value of reagent B, which the manufacturer judged to be more stable at low concentrations. The hook effect in reagent B can be a fatal reason for disqualification when selecting reagents in general patient samples which high-concentration samples appear frequently. The first improved reagent C will be able to be used once it is confirmed that it has more stability for various concentration values.