• Investigative Magnetic Resonance Imaging
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• 제19권1호
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• pp.19-30
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• 2015

Purpose: A new compressed sensing technique by iterative truncation of small transformed coefficients (ITSC) is proposed for fast cardiac CINE MRI. Materials and Methods: The proposed reconstruction is composed of two processes: truncation of the small transformed coefficients in the r-f domain, and restoration of the measured data in the k-t domain. The two processes are sequentially applied iteratively until the reconstructed images converge, with the assumption that the cardiac CINE images are inherently sparse in the r-f domain. A novel sampling strategy to reduce the normalized mean square error of the reconstructed images is proposed. Results: The technique shows the least normalized mean square error among the four methods under comparison (zero filling, view sharing, k-t FOCUSS, and ITSC). Application of ITSC for multi-slice cardiac CINE imaging was tested with the number of slices of 2 to 8 in a single breath-hold, to demonstrate the clinical usefulness of the technique. Conclusion: Reconstructed images with the compression factors of 3-4 appear very close to the images without compression. Furthermore the proposed algorithm is computationally efficient and is stable without using matrix inversion during the reconstruction.

• Journal of Biosystems Engineering
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• 제37권5호
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• pp.327-334
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• 2012

Purpose: The color changes in red pepper during far infrared drying were studied in order to establish a color change model. Methods: The far infrared drying experiments of red pepper were conducted at two temperature levels of 60, $70^{\circ}C$ and two air velocity levels of 0.6 and 0.8 m/s. The results were compared with the hot-air drying method. The surface color changes parameters of red pepper were measured qualitatively based on L (lightness), a (redness), b (yellowness) and total color changes (${\Delta}E$). The goodness of fit of model was estimated using the coefficient of determination ($R^2$), the root mean square error (RMSE), the mean relative percent error (P) and the reduced chi-square (${\chi}^2$). Results: The results show that an increase in drying temperature and air velocity resulted in a decrease in drying time, the values of L (lightness) and a (redness) decreased with drying time during far infrared drying. The developed model showed higher $R^2$ values and lower RMSE, P and ${\chi}^2$ values. Conclusions: The model in this study could be beneficial to describe the color changes of red pepper by far infrared drying.

• 간호행정학회지
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• 제16권1호
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• pp.86-100
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• 2010

Purpose: This study was done to examine the relationship of job satisfaction and organizational commitment of perioperative nurses. Method: The subjects of this study were 500 perioperative nurses from 11 hospitals. The data were collected by self-reporting questionnaires from Sep. 19 to Sep. 27, 2009. Results: There was statistically significant relationship among the five variables. The analyses of covariance of these five variables revealed overall significant (p<.05). Stepwise linear multiple regression analyses were used to examine the influence of these five variables. Results indicated that the variables for verbal abuse (p<.01), workplace climate (p<.01), internal marketing (p<.001), and job transfer (p<.001) contributed significantly to the job satisfaction (adjusted R square=.426), while the verbal abuse (p<.01), internal marketing (p<.01), leadership style (p<.001) and workplace climate (p<.001) did to the organizational commitment (adjusted R square=.351). Canonical correlation analyses revealed that internal marketing and workplace climate contributed most significantly both to job satisfaction and organizational commitment. Conclusion: This study found that all these five nursing managerial factors were important influential on both job satisfaction and organizational commitment of perioperative nurses. Addressing these factors with further research will surely improve the commitment of these nurses and ultimately lead to better perioperative nursing care.

• Archives of Pharmacal Research
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• 제27권10호
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• pp.1009-1015
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• 2004

Quantitative Structure-Resolution Relationship (QSRR) using the Comparative Molecular Field Analysis (CoMFA) software was applied to predict the chromatographic behaviors of chiral drugs with an amine moiety on the chiral cellobiohydrolase (CBH) columns. As a result of the Quantitative CoMFA-Resolution Relationship study, using the partial least square method, prediction of the behavior of drugs with amine moiety upon chiral separation became possible from their three dimensional molecular structures. When a mixed mobile phase of 10 mM aqueous phosphate buffer (pH 7.0) - isopropanol (95 : 5) was employed, the best Quantitative CoMFA-Resolution Relationship, derived from the study, provided a cross-validated $q^2$ = 0.933, a normal $r^2$ = 0.995, while the best Quantitative CoMFA-Separation Factor Relationship, also derived from the study, yielded a cross-validated $q^2$ = 0.939, a normal $r^2$ = 0.991. When all of these results are considered, this QSRR-CoMFA analysis appears to be a very useful tool for the preliminary prediction on the chromatographic behaviors of drugs with an amine moiety inside chiral CBH columns.

• 한국의학물리학회지:의학물리
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• 제33권4호
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• pp.158-163
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• 2022

Purpose: We subjected scanning electron microscopic (SEM) images of the active layer of EBT3 film to texture analysis to determine the dose-response curve. Methods: Uncoated Gafchromic EBT3 films were prepared for direct surface SEM scanning. Absorbed doses of 0-20 Gy were delivered to the film's surface using a 6 MV TrueBeam STx photon beam. The film's surface was scanned using a SEM under 100× and 3,000× magnification. Four textural features (Homogeneity, Correlation, Contrast, and Energy) were calculated based on the gray level co-occurrence matrix (GLCM) using the SEM images corresponding to each dose. We used R-square to evaluate the linear relationship between delivered doses and textural features of the film's surface. Results: Correlation resulted in higher linearity and dose-response curve sensitivity than Homogeneity, Contrast, or Energy. The R-square value was 0.964 for correlation using 3,000× magnified SEM images with 9-pixel offsets. Dose verification was used to determine the difference between the prescribed and measured doses for 0, 5, 10, 15, and 20 Gy as 0.09, 1.96, -2.29, 0.17, and 0.08 Gy, respectively. Conclusions: Texture analysis can be used to accurately convert microscopic structural changes to the EBT3 film's surface into absorbed doses. Our proposed method is feasible and may improve the accuracy of film dosimetry used to protect patients from excess radiation exposure.

• 비파괴검사학회지
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• 제35권1호
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• pp.1-11
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• 2015

본 연구에서는 온라인 감염 씨감자 비파괴선별 시스템을 구축하고 감염 씨감자 선별을 위한 통계적 모델을 개발하여 적용함으로써 선별시스템의 성능을 평가하였다. 선별모델 개발을 위해 토양병 및 잠복 감염의 대표적인 병원성 세균인 pectobacteruim atrosepticum을 인위적으로 씨감자에 감염시켜 씨감자 내부에 병징이 발현되도록 하여 실험하였다. 구축된 선별시스템을 통해 감염 및 정상 씨감자의 투과스펙트럼을 획득한 후 최소자승판별법(partial least square-discriminant analysis)을 이용하여 감염 씨감자 검출모델을 개발하였다. 개발된 모델의 검정결정계수는($R^2$) 0.943이었고 분류의 정확도는 99%(n=80) 이상으로 우수한 선별성능을 보였다. 개발된 온라인 감염 씨감자 선별시스템은 씨감자 선별뿐만 아니라 다양한 농산물의 감염을 검출하는 기반기술로 응용이 가능할 것으로 판단된다.

• Asian-Australasian Journal of Animal Sciences
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• 제30권4호
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• pp.546-553
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• 2017

Objective: An experiment was conducted to determine digestible energy (DE) and metabolizable energy (ME) of different byproduct feed ingredients fed to growing pigs, and to generate prediction equations for the DE and ME in feed ingredients. Methods: Twelve barrows with an initial mean body weight of 31.8 kg were individually housed in metabolism crates that were equipped with a feeder and a nipple drinker. A $12{\times}10$ incomplete Latin square design was employed with 12 dietary treatments, 10 periods, and 12 animals. A basal diet was prepared to mainly contain the corn and soybean meal (SBM). Eleven additional diets were formulated to contain 30% of each test ingredient. All diets contained the same proportion of corn:SBM ratio at 4.14:1. The difference procedure was used to calculate the DE and ME in experimental ingredients. The in vitro dry matter disappearance for each test ingredient was determined. Results: The DE and ME values in the SBM sources were greater (p<0.05) than those in other ingredients except high-protein distillers dried grains. However, DE and ME values in tapioca distillers dried grains (TDDG) were the lowest (p<0.05). The most suitable regression equations for the DE and ME concentrations (kcal/kg on the dry matter [DM] basis) in the test ingredients were: $DE=5,528-(156{\times}ash)-(32.4{\times}neutral\;detergent\;fiber\;[NDF])$ with root mean square error = 232, $R^2=0.958$, and p<0.001; $ME=5,243-(153 ash)-(30.7{\times}NDF)$ with root mean square error = 277, $R^2=0.936$, and p<0.001. All independent variables are in % on the DM basis. Conclusion: The energy concentrations were greater in the SBM sources and were the least in the TDDG. The ash and NDF concentrations can be used to estimate the energy concentrations in the byproducts from oil-extraction and distillation processes.

• 한국통신학회논문지
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• 제29권11A
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• pp.1244-1252
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• 2004

본 논문에서는 Alamouti의 시공간블록부호화를 적용한 다중화 시스템에서 선형 검출기 (zero forcing 또는 minimum mean square error)의 특성을 유도하고 이를 이용하여 수신기의 복잡도를 줄일 수 있는 방안을 제시한다. MMSE 검출기를 적응형으로 설계할 경우 계산해야 하는 가중치 벡터들의 수는 공간 다중화하여 전송한 심볼들의 수만큼 필요하지만 유도한 특성을 이용하면 STBC블록들의 수로 줄어든다. 적응형 알고리즘으로 RLS 알고리즘을 적용해 보았고 복잡도를 50%이상 줄일 수 있었다. 또한 V-Blast검출방법의 복잡도를 줄이기 위해 제안된 정렬QR분해 검출기를 본 시스템에 적용할 때 동일한 특성이 유니타리 행렬 Q와 상위삼각행렬 R에 나타나는 것을 확인하였고, 이 경우에도 성능의 저하 없이 복잡도를 50%까지 줄일 수 있었다.

• International Journal of Ocean System Engineering
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• 제1권2호
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• pp.95-101
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• 2011

Perforated plates with cutouts (or holes) are widely used in structural members. These cutouts provide stress concentration in plates. Extensive studies have been carried out on stress concentration in perforated plates, which consider cutout shapes, boundary conditions, bluntness of cutouts, and more. This study presents stress concentration analyses of perforated plates with not only various cutouts and bluntness but also different cutout orientations. Especially, the effect of cutout orientation on stress concentration is emphasized since structural members have become more complicated recently. To obtain stress concentration patterns, a finite element program, ANSYS, is used. For the designated goal, three parameters are considered as follows: the shapes of polygonal cutouts (circle, triangle, and square), bluntness (a counter measure of radius ratio, r/R), and rotation of cutouts (${\theta}$). From the analyses, it is shown that, in general, as bluntness increases, the stress concentration increases, regardless of the shape and rotation. A more important finding is that the stress concentration increases as the cutouts become more oriented from the baseline, which is the positive horizontal axis (+x). This fact demonstrates that the orientation is also a relatively significant design factor to reduce stress concentration. In detail, in the case of the triangle cutout, orienting one side of the triangle cutout to be perpendicular to the applied tensile forces is preferable. Similarly, in the case of the square cutout, it is more advantageous to orient two sides of square cutout to be perpendicular to the applied tensile force. Therefore, at the design stage, determining the direction of a major tensile force is required. Then, by aligning those polygon cutouts properly, we can reduce stress concentration.

• 한국항공우주학회지
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• 제39권4호
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• pp.321-331
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• 2011

본 연구는 theta 투영법을 이용하여 터보제트 터빈 블레이드 크리프 특성을 파악하는데 목적이 있다. Theta 투영법은 우수한 정확성을 지니고 있어 폭넓게 사용되고 있다. 크리프 특성을 파악하기 위해 고온 크리프 시험을 수행하였으며, 시험 조건은 터보제트 엔진 운용조건과 소재의 비선형 특성을 고려하여 선정하였으며, four theta 모델의 적합성을 평가하기 위해 크리프 시험 결과와 비교하였다. 크리프 시험결과를 활용하여 크리프 곡선은 four theta model을 이용하여 생성하였다. 반복적인 계산을 통하여 비선형 최소자승법을 이용하여 시험 결과에 대해 최적의 theta 값을 도출하였다. Theta 투영법을 이용하여 크리프 곡선을 생성한 결과 $R^2$값이 0.95이상의 우수한 정확성을 지니는 것을 확인하였다. 또한 four theta 모델의 검정을 위해 수행한 시험 결과와 비교하여 예측된 theta 값이 90.0%의 정확도를 가지어, theta 투영법은 크리프 거동을 예측하여 설계목적에 이용하기 위해 유용하게 사용될 수 있다.