Earticle

This study shows a variance regularization method in order to obtain the stable optimal solutions, when a numerical method accelerating design variables is used for material topology optimization algorithm. Since a moved and regularized Heaviside function used in the accelerated method is composed of nonlinear concave and convex functions in a given design domain between 0 and 1, design variables below 0.5 can move fast toward the value of 0 and those over 0.5 are rapidly located to the value of 1. However optimal solutions may be not stable due to singularity of element stiffness, while the accelerated design variables are too closed to value 0. In particular this instability may occur to the accelerated method-based material topology optimization algorithms much repeating the moved and regularized Heaviside function. In order to resolve the problem, in this study, a variance regularization is formulated within a linear governing equation for structural analyses of optimization procedures. Numerical examples for topologically optimally modeling a linear elastostatic MBB-beam verify that the accelerated method of design variables take numerical stability of topological optimal solutions by being associated with the variance regularization method.

본 연구는 골프장 농약잔류량조사에서 가압용매추출장치를 이용한 시료전처리 개선방안을 찾고자 하였다. 가압용매추 출장치의 조건은 압력 1,500 psi, 온도 100oC, 추출용매 조성은 디클로로메탄과 아세톤의 1:1(v/v)이다. 다성분 농약의 추 출방법별 회수율을 비교해 본 결과 가압용매추출방법은 78.1 ~ 105.9%였으며, Liquid-Liquid 용매추출법의 회수율은 78.1 ~ 104.5%로 평균회수율은 차이가 없었으며, 유효회수율 범위인 70 ~ 120%을 만족하였다. 가압용매추출방법이 시료 의 추출 및 정제 단계의 시료 전처리 시간을 감소시킬 수 있고, 사용되는 용매 사용량 또한 감소시킬 수 있음을 알 수 있었다.

In this study, ASE (accelerated solvent extraction) analysis was developed to reduce sample preparation time in analysis of pesticides residues of Golf field. In the condition of 1,500 psi and 100oC, the 1:1 (v/v) ratio of dichloromethane to acetone was used as an extraction solvent. The extraction and purification efficiency of ASE (78.1-105.9%) was similar to liquid-liquid solvent extraction (70 ~ 106%). And it satisfies the requirements of effective recovery rate ranges 78.1 ~ 104.5% This results shows that ASE method can reduce sample preparation time as the extraction and purification steps were combined, and the extraction solvent was significantly reduced.

In this study, we investigated the degradation characteristics of KIV, HIV, and HFIX cables according to the temperature and humidity by using accelerated temperature humidity testing method. In order to identify the degradation properties, cables were put into the oven with two different conditions, only temperature stress at 130oC, and temperature-humidity stress at 90oC with 45% RH. the changes in weight, thickness, char length and insulation resistance were measured. Although HFIX cables had weakness of moisture, the insignificant change in weight, length and insulation resistance were measured in the samples under the temperature-humidity stress condition. Therefore, extra experiments including the effects of external condition should proceed in the next research.

보증데이터의 분석 목적은 크게 세 가지로 분류할 수 있다. 첫째 현상파악이다. 현 상파악은 각 부품별 보증클레임데이터를 이용하여 각부품의 현수준을 분석하는 방법 으로 단변량 분석방법이다. 즉 부품의 현 수명(신뢰도)를 분석할 수 있는 생명표법, 카 랜마이어 방법이 대표적이라고 할 수 있다. 둘째, 고장원인분석이다. 부품의 고장에 다 양한 인자가 영향을 줄 것이다. 생산부터 고객의 사용조건까지 다양할 것이다. 이처럼 단순히 사용시간을 가지고 분석하는 것이 아닌 다양한 원인변수를 통해서 원인을 파 악하는 다변량 방법이다. 셋째, 단변량이 아닌 다변량 수명예측방법으로 그 모형의 구 조에 따라 비례적 위험함수 모형 (proportional hazards)의 가정을 적용하는 COX 모형 과 가속화 시간 (accelerated failure time)을 적용하는 AFT 모형으로 분류할 수 있다. 본 연구에서는 예측에 적합한 AFT모형을 통해서 생존 시간 자체에 대한 설명변수 의 효과를 모형화하고 각 부품의 수명을 예측하고자 한다. 이 방법을 제시하는 이유는 COX모형의 경우 준 모수적 방법으로 위험함수의 모수적 유형을 지정하지 않아도 된 다는 장점을 가지고 있지만, 위험 함수 보다는 설명변수의 효과를 추정에 그 주 목적 이 있기 때문에 모형의 결과를 수명예측에 사용하기에는 부적합하다. 본 논문에서는 다양한 인자를 고려하여 부품의 수명 및 수명에 대한 설명변수의 효 과를 모형화 하여 보증데이터를 분석하는 AFT 모형을 제시 하였고 실제 보증데이터 를 통해서 AFT 모형의 활용성을 확인하였다.

The matrix completion problem is to reconstruct an unknown matrix with low-rank or approximately low-rank constraints from its partially known samples. Most methods to solve the rank minimization problem are relaxing it to the nuclear norm regularized least squares problem. Recently, there have been some simple and fast algorithms based on hard thresholding operator. In this paper, we propose an accelerated iterative hard thresholding method for matrix completion (AIHT). Then we report numerical results for solving noiseless and noisy matrix completion problems and image reconstruction. The numerical results suggest that significant improvement can be achieved by our algorithm compared to the other reported methods, especially in terms of CPU time.

Glycated hemoglobin ($HbA_{1c}$) has been commonly used to screen and diagnose for patients with diabetes mellitus. Here the accelerated procedure of microwave-assisted sample treatment from acid hydrolysis to enzyme digestion followed by isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) was optimized and applied to measure $HbA_{1c}$ in an effort to speed up analysis time. First, two signature peptides of $HbA_{1c}$ and hemoglobin $A_0$ were certified with amino acid analysis by setting optimized acid hydrolysis conditions to $150^{\circ}C$, 1.5 h and $10{\mu}M$ sample concentration in 8 M hydrochloric acid. Consequently, the accurate certified peptides above were used as calibration standards to implement the proteolytic procedure with endoproteinase Glu-C at $37^{\circ}C$, 700 W for 6 h. Compared to the traditional method, the microwave heating not only shortened dramatically sample preparation time, but also afforded comparable recovery yields. The optimized protocol and analytical conditions in this study are suitable for a primary reference method of $HbA_{1c}$ quantification with full SI-traceability and other similar proteins in complex biological samples.

The CSPE cables are used for three years in nuclear power plant. The accelerated thermal aging of chloro sulfonate polyethylene(CSPE) jacket of test cables were carried out for the period equal to 10, 20 and 30 years in air at 90 and $100^{\circ}C$, respectively. The electrical volume resistivity, density, XPS, FE-SEM, EDS and XRF of the accelerated thermal aging of CSPE were measured. The validation of condition monitering method of accelerated thermal aging CSPE was estimated by them. The best validation of condition monitoring method of accelerated aging CSPE is electrical volume resistivity because change thermal of the specimen showed distinction.

Generation of optimum planar B-spline curve in terms of minimum deviation and required fairness to approximate a target shape defined by a strip-shaped unorganized 2D point cloud is studied. It is proposed to use the location of control points as variables within the geometric optimization framework of point distance minimization. An adaptive simulated annealing heuristic optimization algorithm is developed to iteratively update an initial approximate curve towards the target shape. The new implementation comprises an adaptive cooling procedure in which the temperature change is adaptively dependent on the objective function evolution. It is shown that the proposed method results in an improved convergence speed when compared to the standard simulated annealing method. A couple of examples are included to show the applicability of the proposed method in the surface model reconstruction directly from point cloud data.

저압 개폐기는 에어컨, 냉동기, 산업용 청소기, 전기온수기, 공조기, 펌프, 콤프레션 등의 모터제어 및 히터와 조명기기의 개폐 둥에 광범위하게 이용되는 개폐장치이다. 저압 전자개폐기는 수 천회에서 수백만회까지 빈번한 개폐 사용조건으로 인해 시험 규격에서는 개폐시험을 통해 제품의 수명을 검증하도록 되어 있으며 과다한 시간이 소요된다. 따라서 시험 시간을 단축하기 위한 가속수명 시험이 필요하게 되었으며 가속 스트레스인 과도 회복전압(TRV)의 피크비율(factor ${\gamma}$) 변화에 따라 저압개폐기의 전기적 수명 시험을 실시하였으며 시험결과를 바탕으로 가속 수명 시험을 하기 위한 가속계수를 산출하였다.

In the previous study, the inverse perturbation method was used to identify structural damages. Because all unmeasured DOFs were considered as unknown variables, considerable computational effort was required to obtain reliable results. Thus, in the present study, a system condensation method is used to transform the unmeasured DOFs into the measured DOFs, which eliminates the remaining unmeasured DOFs to improve computational efficiency. However, there may still arise a numerically ill-conditioned problem, if the system condensation is not adequate for numerical Programming or if the system condensation is not recalibrated with respect to the structural changes. This numerical problem is resolved in the present study by adopting more accurate accelerated improved reduced system (AIRS) as well as by updating the transformation matrix at every step. The criterion on the required accuracy of the condensation method is also proposed. Finally, numerical verification results of the present accelerated inverse perturbation method (AIPM) are presented.

In this paper, an accelerated lifetime test method of MgO thin film is suggested. The most important test factors are surface temperature of the PDP, gas pressure, the applied voltage and frequency. The standard test conditions are $50^{\circ}C$, 400Torr, 20% over voltage and 300kHz ,respectively. The accelerated lifetime of MgO is significantly varied with the MgO preparing conditions.

In this work, the friction and wear behavior under' various lubrication regimes were investigated. The objective of this work is to develop an Accelerated Life Test (ALT) method for the durability evaluation of a machine element which is operated under lubrication. Electric contact resistance and frictional forces were measured with respect to a wide range of the loads and speeds under various lubrication regimes using a pin-on-disk type tribotester. From the experimental results, it could be found that an effective and reliable ALT method could be achieved by controlling the lubrication regime through the measurements of friction coefficient and contact resistance with respect to load and sliding speed.

In this paper we present an adaptive method for accelerating conventional Maximum Entropy Method (MEM) for restoration of Passive Millimeter-Wave (PMMW) image from its blurred and noisy version. MEM is nonlinear and its convergence is very slow. We present a new method to accelerate the MEM by using an exponent on the correction ratio. In this method the exponent is computed adaptively in each iteration, using first-order derivatives of deblurred image in previous two iterations. Using this exponent the accelerated MEM emphasizes speed at the beginning stages and stability at later stages. In accelerated MEM the non-negativity is automatically ensured and also conservation of flux without additional computation. Simulation study shows that the accelerated MEM gives better results in terms of RMSE, SNR, moreover, it takes only about 46% lesser iterations than conventional MEM. This is also confirmed by applying this algorithm on actual PMMW image captured by 94 GHz mechanically scanned radiometer.

미꾸라지에서의 Nitrofuran계 대사물질인3-amino-2-oxazolidone(AOZ), 5-morpholinomethyl-3-amino-2-oxazolidinone(AMOZ), 1-ammino-hydantoin (AHD)와 semicarbazide(SEM)의 잔류량을 검사하기 위해HPLC-MS/MS를 이용한 신속한 정량법이 개발되었다. 2-nitrobenzaldehyde (2-NBA)를 이용해 $50^{\circ}C$에서 1시간 동안 산 가수분해와 유도체화 과정을 거친 뒤에, 액-액 분배로 정제와 추출을 하였다. 회수율은 음성시료에 3가지 농도 0.5, 1.0, $2.0{\mu}g/kg$의 표준액을 첨가하여 평가하였고 평균 회수율은 75.1-108.1% 이었다. 정밀성(%RSD)은 일내 8.7% 이하, 일간 8.5% 이하였다. 직선성은 NBAOZ는 $0.2-20{\mu}g/Kg$, NBAMOZ는 $0.8-20{\mu}g/Kg$, NBAHD는 $0.2-20{\mu}g/Kg$, NBSEM 는 $0.1-20{\mu}g/Kg$ 범위에서 모두 상관계수 0.99이상이었다. 검출한계(LOD)는 NBAOZ $0.06{\mu}g/Kg$, NBAMOZ $0.24{\mu}g/Kg$, NBAHD $0.06{\mu}g/Kg$, NBSEM $0.03{\mu}g/Kg$이었고, 정량한계(LOQ)는 NBAOZ $0.2{\mu}g/Kg$, NBAMOZ $0.8{\mu}g/Kg$, NBAHD $0.2{\mu}g/Kg$, NBSEM $0.1{\mu}g/Kg$ 이었다. 가수분해 및 유도체화 소요시간을 1시간으로 줄여 만든 신속 간편한 이 시험법이 미꾸라지 중 nitrofuran metabolites잔류량 분석에 적합함을 확인할 수 있었다.

A rapid method using HPLC-MS/MS has been developed for quantitative determination of the metabolites of nitrofurans, namely 3-amino-2-oxazolidone (AOZ), 5-morpholinomethyl-3-amino-2-oxazolidinone (AMOZ), 1-ammino-hydantoin (AHD) and semicarbazide (SEM) in loach. The extraction procedure was founded on simultaneous acidic hydrolysis and derivatization using 2-nitrobenzaldehyde (2-NBA) for 1 hour at $50^{\circ}C$, followed by purification with liquid-liquid extraction. Recovery was evaluated by spiking standards into blank samples at three levels (0.5, 1.0 and $2.0{\mu}g/kg$), and the mean recovery was 75.1-108.1%. Precision values expressed as the relative standard deviation (%RSD) were ${\leq}8.7%$ and ${\leq}8.5%$ for intra-day and inter-day precision, respectively. Linearity was studied in the range of $0.2-20{\mu}g/Kg$ for NBAOZ, $0.8-20{\mu}g/Kg$ for NBAMOZ, $0.2-20{\mu}g/Kg$ for NBAHD, and $0.1-20{\mu}g/Kg$ for NBSEM, and the obtained coefficient correlations (r) were ${\geq}0.99$ for all compounds. Limits of detection (LODs) for the derivatized nitrofuran metabolites were established at $0.06{\mu}g/Kg$ for NBAOZ, $0.24{\mu}g/Kg$ for NBAMOZ, $0.06{\mu}g/Kg$ for NBAHD, and $0.03{\mu}g/Kg$ for NBSEM. Limits of quantification (LOQs) were established at $0.2{\mu}g/Kg$ for NBAOZ, $0.8{\mu}g/Kg$ for NBAMOZ, $0.2{\mu}g/Kg$ for NBAHD, and $0.1{\mu}g/Kg$ for NBSEM. This simplified rapid method for reducing the derivatization and hydrolysis times can be applied to the determination of nitro-furan residues in loach.

Although a large number of genetic variants have been identified to be associated with common diseases through genome-wide association studies, there still exits limitations in explaining the missing heritability. One approach to solving this missing heritability problem is to investigate gene-gene interactions, rather than a single-locus approach. For gene-gene interaction analysis, the multifactor dimensionality reduction (MDR) method has been widely applied, since the constructive induction algorithm of MDR efficiently reduces high-order dimensions into one dimension by classifying multi-level genotypes into high- and low-risk groups. The MDR method has been extended to various phenotypes and has been improved to provide a significance test for gene-gene interactions. In this paper, we propose a simple method, called accelerated failure time (AFT) UM-MDR, in which the idea of a unified model-based MDR is extended to the survival phenotype by incorporating AFT-MDR into the classification step. The proposed AFT UM-MDR method is compared with AFT-MDR through simulation studies, and a short discussion is given.

A new method of dose calculation algorithm, called GPU-accelerated Monte Carlo and collapsed cone Convolution (GMCC) was developed to improve the calculation speed of BNCT treatment planning system. The GPU-accelerated Monte Carlo routine in GMCC is used to simulate the neutron transport over whole energy range and the Collapsed Cone Convolution method is to calculate the gamma dose. Other dose components due to alpha particles and protons, are calculated using the calculated neutron flux and reaction data. The mathematical principle and the algorithm architecture are introduced. The accuracy and performance of the GMCC were verified by comparing with the FLUKA results. A water phantom and a head CT voxel model were simulated. The neutron flux and the absorbed dose obtained by the GMCC were consistent well with the FLUKA results. In the case of head CT voxel model, the mean absolute percentage error for the neutron flux and the absorbed dose were 3.98% and 3.91%, respectively. The calculation speed of the absorbed dose by the GMCC was 56 times faster than the FLUKA code. It was verified that the GMCC could be a good candidate tool instead of the Monte Carlo method in the BNCT dose calculations.

The microstructure and compressive strength of a 0.38 water-to-cement mass ratio (w/c) cement paste when subjected to accelerated-curing by microwave energy and autoclave curing were compared with a normal curing method by soaking in saturated-lime deionized water at 25 oC. The morphology, atom ratio of Si/Ca versus Al/Ca, phase composition by XRD, and compressive strength were measured in this study. The results indicate the presence of needle-like ettringite (Aft) in pastes that had been cured using the autoclave method. However, the saturated-lime deionized water cured paste showed lath-like or plate-like shapes and did not appear to produce ettringite (Aft). In addition, the microwave-cured paste indicated some evidence of ettringite. The range of Si/Ca and Al/Ca ratios of the autoclave-cured paste were 0.039? 0.052, and 0.207 ? 0.234,respectively, while in the microwave-cured paste the ratio shifted to 0.079? 0.091. The compressive strength of the autoclavecured cement paste showed an increase in strength at an early age, while the strength decreased after 7 days of hydration.