• 한국의학물리학회지:의학물리
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• 제21권1호
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• pp.70-77
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• 2010

골다공증 환자를 대상으로 이중 에너지 X선 흡수(DEXA) 방법을 이용한 골밀도 영상에서는 T-score를 측정하고 자기공명영상 기법 중 확산강조영상에서는 신호대 잡음비와 현성 확산 계수를 측정한 다음 T-score변화에 따라 신호대 잡음비와 현성 확산 계수가 어떻게 변화하는지 알아보았다. 골다공증이 없는 건강한 사람 30명과 2009년 1월부터 2009년 12월까지 허리 통증으로 내원한 환자 중 단순 방사선 촬영에서 골다공증 소견이 보이는 환자 30명을 대상으로 Dual Energy X-ray Absorptiometry (DEXA)를 이용하여 척추 L1-L4부위의 T-score를 측정 후 각각의 척추에 대해서 골감소증, 골다공증으로 분류하였다. 1.5T MR scanner를 이용하여 b value를 $400\;s/mm^2$으로 획득한 확산강조영상에서는 L1-L4 네 부위에서 신호 강도(signal intensity)측정을 하였고 현성 확산 계수(apparent diffusion coefficient; ADC) map 영상에서는 현성 확산 계수를 측정하였다. 정량적 분석방법으로 관심영역의 T-score와 신호대 잡음비(signal to noise ratio)와 ADC를 구하고 평균화 하여 관심영역에서 T-score변화에 따른 신호대 잡음비와 현성확산계수의 변화를 비교하였고 T-score에 의해 골감소증, 골다공증으로 분류하여 그룹별로 신호대 잡음비와 현성확산계수의 변화도 비교하였다. 정성적인 분석방법은 육안적으로 건강한 그룹과 골감소증, 골다공증그룹의 T1강조 시상면 영상에서 요추체중 L4 부위에서의 신호강도 차이를 알아보았다. 정량적 분석에서 골감소증 그룹과 골다공증그룹은 T-score가 감소함에 따라 확산강조영상에서의 신호대 잡음비가 감소하여 나타났으며 골다공증 그룹에서 신호대 잡음비가 가장 크게 감소하였다. ADC map영상에서는 골감소증그룹과 골다공증 그룹은 T-score가 감소함에 따라 현성 확산 계수는 감소해서 나타났고 건강한 그룹과 골감소증 및 골다공증 그룹의 경우 현성 확산 계수 차이는 골다공증 그룹에서 현성 확산 계수가 가장 낮게 나타났다. 정성적 분석에서는 건강한 그룹과 골감소증 및 골다공증 그룹에서 L4 부위의 신호강도는 건강한 그룹에서 가장 낮게 나타났고 골다공증그룹에서 높게 나타났다. 골다공증이 진행 될수록 신호대 잡음비와 현성 확산계수는 감소하고 T1강조 영상에서는 신호강도가 증가 하는 결과를 얻었고 자기공명검사가 골다공증 진단에 유용함을 알 수 있었다.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2002년도 Current Trends in Toxicological Sciences
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• pp.110-110
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• 2002

15-Deoxy-$\Delta$12, 14-prostaglandin J2 (15-deoxy-PGJ2), a naturally occurring ligand activates the peroxisome proliferator-activated receptor-$\gamma$(PPAR-$\gamma$). It was known to have promoting ability of nerve growth factor(NGF)-induced neurite extension. However, it is not clear yet as to what signaling pathway is involved in its promoting ability of neurite extension.(omitted)

• Journal of applied mathematics & informatics
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• 제4권2호
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• pp.477-485
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• 1997

Let E be a smooth Banach space. Suppose T:$E \rightarrow E$ is a strongly accretive map. It is proved that each of the two well known fixed point iteration methods (the Mann and ishikawa iteration methods), under suitable conditions converges strongly to a solution of the equation $T_x=f$.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.141-142
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• 2010

• Journal of Yeungnam Medical Science
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• 제39권1호
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• pp.24-30
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• 2022

Background: Texture analysis has been used as a method for quantifying image properties based on textural features. The aim of the present study was to evaluate the usefulness of magnetic resonance imaging (MRI) texture analysis for the evaluation of viable ovarian tissue on the perfusion map of ovarian endometriosis. Methods: To generate a normalized perfusion map, subtracted T1-weighted imaging (T1WI), T1WI and contrast-enhanced T1W1 with sequences were performed using the same parameters in 25 patients with surgically confirmed ovarian endometriosis. Integrated density is defined as the sum of the values of the pixels in the image or selection. We investigated the parameters for texture analysis in ovarian endometriosis, including angular second moment (ASM), contrast, correlation, inverse difference moment (IDM), and entropy, which is equivalent to the product of area and mean gray value. Results: The perfusion ratio and integrated density of normal ovary were 0.52±0.05 and 238.72±136.21, respectively. Compared with the normal ovary, the affected ovary showed significant differences in total size (p<0.001), fractional area ratio (p<0.001), and perfusion ratio (p=0.010) but no significant differences in perfused tissue area (p=0.158) and integrated density (p=0.112). In comparison of parameters for texture analysis between the ovary with endometriosis and the contralateral normal ovary, ASM (p=0.004), contrast (p=0.002), IDM (p<0.001), and entropy (p=0.028) showed significant differences. A linear regression analysis revealed that fractional area had significant correlations with ASM (r²=0.211), IDM (r²=0.332), and entropy (r²=0.289). Conclusion: MRI texture analysis could be useful for the evaluation of viable ovarian tissues in patients with ovarian endometriosis.

• 한국멀티미디어학회논문지
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• 제17권6호
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• pp.733-740
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• 2014

With the development and spread of 3D display, users can easily experience an augmented reality with 3D features. Therefore, the demand for content of an augmented reality is exponentially growing in various fields. A traditional augmented reality environment was generally created by CG(Computer Graphics) modelling production tools. However, this method takes too much time and efforts to create an augmented environment. To create an augmented environment similar to the real world, everything in the real world should be measured, gone through modeling, and located in an augmented environment. But the time and efforts spent in the creation don't produce the same environment as the real world, making it hard for users to feel the sense of reality. In this study, multi-scale 3D panorama content augmented system is suggested by using a depth-map. By finding matching features from images to add 3D features to an augmented environment, a depth-map is derived and embodied as panorama, producing high-quality augmented content system with a sense of reality. With this study, limits of 2D panorama technologies will be overcome and a sense of reality and immersion will be provided to users with a natural navigation.

• Investigative Magnetic Resonance Imaging
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• 제25권2호
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• pp.118-128
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• 2021

Purpose: To investigate the value of MR textural analysis, including use of diffusion-weighted imaging (DWI) to differentiate malignant from benign soft-tissue tumors on 3T MRI. Materials and Methods: We enrolled 69 patients (25 men, 44 women, ages 18 to 84 years) with pathologically confirmed soft-tissue tumors (29 benign, 40 malignant) who underwent pre-treatment 3T-MRI. We calculated MR texture, including mean, standard deviation (SD), skewness, kurtosis, mean of positive pixels (MPP), and entropy, according to different spatial-scale factors (SSF, 0, 2, 4, 6) on axial T1- and T2-weighted images (T1WI, T2WI), contrast-enhanced T1WI (CE-T1WI), high b-value DWI (800 sec/mm²), and apparent diffusion coefficient (ADC) map. We used the Mann-Whitney U test, logistic regression, and area under the receiver operating characteristic curve (AUC) for statistical analysis. Results: Malignant soft-tissue tumors had significantly lower mean values of DWI, ADC, T2WI and CE-T1WI, MPP of ADC, and CE-T1WI, but significantly higher kurtosis of DWI, T1WI, and CE-T1WI, and entropy of DWI, ADC, and T2WI than did benign tumors (P < 0.050). In multivariate logistic regression, the mean ADC value (SSF, 6) and kurtosis of CE-T1WI (SSF, 4) were independently associated with malignancy (P ≤ 0.009). A multivariate model of MR features worked well for diagnosis of malignant soft-tissue tumors (AUC, 0.909). Conclusion: Accurate diagnosis could be obtained using MR textural analysis with DWI and CE-T1WI in differentiating benign from malignant soft-tissue tumors.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제30권2호
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• pp.109-129
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• 2023

In this paper, we introduce a second order linear differential operator ^T□: C^∞ (M) → C^∞ (M) as a natural generalization of Cheng-Yau operator, [8], where T is a (1, 1)-tensor on Riemannian manifold (M, h), and then we show on compact Riemannian manifolds, divT = divT^t, and if divT = 0, and f be a smooth function on M, the condition ^T□ f = 0 implies that f is constant. Hereafter, we introduce T-energy functionals and by deriving variations of these functionals, we define T-harmonic maps between Riemannian manifolds, which is a generalization of L_k-harmonic maps introduced in [3]. Also we have studied fT-harmonic maps for conformal immersions and as application of it, we consider fL_k-harmonic hypersurfaces in space forms, and after that we classify complete fL₁-harmonic surfaces, some fL_k-harmonic isoparametric hypersurfaces, fL_k-harmonic weakly convex hypersurfaces, and we show that there exists no compact fL_k-harmonic hypersurface either in the Euclidean space or in the hyperbolic space or in the Euclidean hemisphere. As well, some properties and examples of these definitions are given.

• Journal of Animal Science and Technology
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• 제51권3호
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• pp.249-254
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• 2009

돈분뇨 부숙과정에서의 Mg원 첨가에 따른 MAP 크리스탈 결정체 형성과 부숙과정에 미치는 영향을 조사하였다. 돈분뇨내 수용성인산 기준 1.2M비로 Mg원을 첨가하여 부숙시킨 경우와 첨가하지 않고 부숙한 경우를 비교하여 실험한 결과 Mg원 첨가에 의한 부숙과정에서의 유기물분해 저해 현상은 관찰되지 않았다. Mg원을 첨가한 경우 분뇨 내 $NH_4$와 $PO_4$가 함께 반응하여 MAP 크리스탈 결정체를 형성함에 따라 $NH_4$-N의 함량이 낮아졌으며 이는 부숙과정에서의 암모니아 가스 형태로의 질소소실을 낮추어주는 결과가 됨을 알 수 있었다. 수용성인의 함량 또한 Mg원을 첨가한 경우에 낮아져 최종 부숙퇴비의 총인중 수용성인의 비율이 감소함을 알 수 있었다. 따라서 부숙과정에서의 Mg원 첨가는 최종 부숙퇴비의 비료성분 보존과 완효도 증가효과가 있음을 알 수 있었다. 최종퇴비의 X-Ray Diffraction 시험결과 부숙과정에서 MAP 결정체가 형성됨을 알 수 있었으며 2.8 mm 이하의 입자크기에서 형성된 결정체가 많음을 알 수 있었다. 또한 입자크기별 질소와 인 성분 분포율을 비교한 결과 2.8 mm 이하의 입자크기에 질소와 인성분의 2/3 이상이 분포해 있음을 알 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제15권9호
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• pp.1257-1262
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• 2002

The objective was to identify the appropriate form of progesterone, which exhibits compact reproductive responses in Awassi ewes during mid to late seasonal anestrous period. Forty-eight Awassi ewes were randomly allocated into four groups to be treated with 60 mg medroxyprogesterone acetate (MAP), 30 mg fluorogestone acetate (FGA), 40 mg FGA, or 600 mg progesterone sponges. After a 12 day period, sponges were removed and ewes were administered i.m. with 600 IU PMSG (d 0, 0 h). Five harnessed Awassi rams were turned-in with the ewes to detect heat. Ewes were checked for breeding marks at 6 h intervals for 5 days. Blood samples were collected from all ewes for analysis of progesterone concentrations. Pretreatment (d -13 and -12) progesterone concentrations were ${\leq}0.2ng/mL$ among all ewes and were indicative of seasonal anestrous period. On d 0, progesterone concentrations were elevated to $1.4{\pm}0.1ng/mL$ in ewes received progesterone sponges only and were higher (p<0.0001) than those (${\leq}0.2ng/mL$) administered MAP or FGA sponges. Progesterone concentrations returned to their basal values of <0.2 ng/mL within 24 h of sponge removal and were similar (p>0.1) among all ewes. Incidence of estrus was similar (p>0.1) among the four groups and occurred in 75% (9/12), 82% (9/11), 67% (8/12) and 58% (7/12) of the ewes receiving MAP, 30 mg FGA, 40 mg FGA and progesterone sponges, respectively. Estrous responses occurred 14.7, 20 and 13.6 h earlier in progesterone-sponge-treated ewes than those of MAP- (p<0.04), 30 mg FGA- (p<0.01) and 40 mg FGA-treated (p=0.06) ewes, respectively. Induced estrus conception rates were 50% (6/12), 55% (6/11), 50% (6/12) and 42% (5/12), out of which 4/6, 4/6, 3/6 and 3/5 lambed 151 days following d 0, and were similar (p>0.1) among ewes of the four treatment groups. Ewes that returned to estrus 16 to 20 days following d 0 were 5/12, 5/11, 6/12 and 4/12 ewes treated with MAP, 30 mg FGA, 40 mg FGA and progesterone sponges, respectively, and all lambed 169 days later. Overall lambing rates were 75% (9/12), 82% (9/11), 75% (9/12) and 58% (7/12) ewes treated with MAP, 30 mg FGA, 40 mg FGA and progesterone sponges, respectively. Results demonstrate that applications of MAP, 30 mg FGA, 40 mg FGA and progesterone sponges Awassi ewes were equally effective in induction of estrus and tended to favor both types of FGA and MAP in overall lambing rates over progesterone sponges during the seasonal anestrous period.