• The Korean Journal of Nuclear Medicine
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• v.34 no.6
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• pp.487-496
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• 2000

Purpose: The aim of this study is to investigate the reproducibility of the quantitative assessment of segmental wall motion and systolic thickening provided by an automatic quantitation algorithm. Materials and Methods: Tc-99m-MIBI gated myocardial SPECT with dipyridamole stress was performed in 31 patients with known or suspected coronary artery disease (4 with single, 6 with two, 11 with triple vessel disease; ejection fraction $51{\pm}14%$) twice consecutively in the same position. Myocardium was divided into 20 segments. Segmental wall motion and systolic thickening were calculated and expressed in mm and % increase respectively, using $AutoQUANT^{TM}$ software. The reproducibility of this quantitative measurement of wall motion and thickening was tested. Results: Correlations between repeated measurements on consecutive gated SPECT were excellent for wall motion (r=0.95) and systolic thickening (r=0.88). On Bland-Altman analysis, two standard deviation was 2 mm for repeated measurement of segmental wall motion, and 20% for that of systolic thickening. The weighted kappa values of repeated measurements were 0.807 for wall motion and 0.708 for systolic thickening. Sex, perfusion, or segmental location had no influence on reproducibility. Conclusion: Segmental wall motion and systolic thickening quantified using $AutoeUANT^{TM}$ software on gated myocardial SPECT offers good reproducibility and is significantly different when the change is more than 2 mm for wall motion and more than 20% for systolic thickening.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.11
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• pp.2106-2115
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• 1994

As a pre processing for an edge detection process. edge preserving smoothing algorithm is proposed. For this purpose we used the interpolation method using B-spline basis function and scaling of digital images. By approximation of continuous function from descrete data using B-spline basis function. undetermined data between two sample can be computed. so that they smooth the surfaces of objects. Some edges having mainly low frequency components are detected using down scaling of the images. Edge maps from proposed pre processed images are hardly affected by the varying space constants($\sigma$) and threshold values used in detecting zero-crossing.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.5
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• pp.1304-1312
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• 1993

The buoyancy effects on mixed convection heat transfer over a flat plate surface with unheated starting length is reported. The governing equations are solved by a finite difference method using Patankar scheme and the solution was numerically obtained for various mixed convection parametr $Gr_{x}/Re_{x}^3$, and Prandtl number of 0.7 Local heat flux was measured by using Schilieren Interferometer. The local heat transfer results show that the presence of the unheated starting length can significantly accentuate the effects of buoyancy. The degree of accentuation of the buoyancy effects is strongly influenced by the magnitude of $Gr_{x}/Re_{x}^3$. When the parameter is larger than the order of $10^{-3}$, the contribution of natural convection to the heat transfer coefficients increased significantly due to the unheated starting length. In contrast, when $Gr_{x}/Re_{x}^3$ is smaller then about $10^{-5}$ , the buoyancy contribution is essentially unaffected by the unheated starting length. The shape of the velocity profile is also found to be highly responsive to the interaction between the buoyancy and the starting length.

• Journal of Energy Engineering
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• v.17 no.1
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• pp.1-7
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• 2008

The present study has been conducted to understand the heat and mass transfer characteristics of humid airflow in frosting conditions. A flat plate of aluminum was used for the simulation of flat surface part of the fin of the heat exchanger. The aluminum surface temperatures were measured and analyzed to clarify the heat and mass transfer characteristics under frosting conditions. Also, the pressure drops were measured to clarify the air-blocking effect of frost in the mini channel of the air-side hoot exchangers. A data reduction method was developed far the analysis of local characteristics of humid air under frosting conditions.

• The KIPS Transactions:PartC
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• v.12C no.4 s.100
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• pp.535-542
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• 2005

This paper proposes an on-demand ad hoc routing protocol, Node Density Based Routing (NDBR), which enhances the routing performance applying a new method to establish alternate patlis. It is important to reserve alternate paths for the route from source to destination in mobile ad hoc networks that are susceptible to failure due to the movement or the power exhaustion of mobile nodes. NDBR aims to establish a route that contains more alternate paths toward the destination by involving intermediate nodes with relatively more adjacent nodes in a possible route, and introduces a new routing criterion called 'node density.' This approach can localize the effects of route failures, and reduce control traffic overhead and route reconfiguration time by enhancing the reachability to the destination node without source-initiated route re-discoveries at route failures. This paper describes the route setup procedure using node density and the route re-configuration procedures employing alternate path information at the intermediate nodes. We show the performance of our routing schemes through a series of simulations using the Network Simulator 2 (ns-2).

• Korean Journal of Psychosomatic Medicine
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• v.9 no.1
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• pp.37-48
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• 2001

Objectives : The purpose of this study was to evaluate the difference of psychometric analysis among patients with Post-traumatic organic mental disorder according to the lesion of MRI finding of traumatic brain injury. Methods : We divided 35 patients into 4 groups according to the lesion of MRI finding of brain injury. We evaluated the difference of the subscales of MMPI and K-WAIS among 4 groups with Post-traumatic organic mental disorder by ANOVA. Results : We found no significant difference of all subscales of MMPI and K -WAIS among 4 groups by ANOVA. Compared Rt hemispheric injury group with Lt hemispheric injury group by independent t-test, the depression scale in MMPI scored significantly higher in Lt hemispheric injury group, and the block design in K-WAIS scored significantly lower in Rt hemispheric injury group. Conclusion : This study suggests that Lt hemispheric injury be significantly related to depression, and Rt hemispheric injury be significantly related to visuospatial ability.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.6 s.237
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• pp.671-686
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• 2005

The transient nature and complex geometries of two-phase gas-liquid flows cause fundamental difficulties when measuring flow velocity using an electromagnetic flowmeter. Recently, a current-sensing flowmeter was introduced to obtain measurements with high temporal resolution (Ahn et al.). In this study, current-sensing flowmeter theory was applied to measure the fast velocity transients in slug flows. The velocity fields of axisymmetric gas-liquid slug flow in a vertical pipe were obtained using Volume-of-Fluid (VOF) method, and the virtual potential distributions for the electrodes of finite size were also computed using the finite volume method for simulating slug flow. The output signal prediction for slug flow was carried out from the velocity and virtual potential (or weight function) fields. The flowmeter was numerically calibrated to obtain the cross-sectional liquid mean velocity at an electrode plane from the predicted output signal. Two calibration parameters are proposed for this procedure: a flow pattern coefficient and a localization parameter. The flow pattern coefficient was defined by the ratio of the liquid resistance between the electrodes for two-phase flow with respect to that for single-phase flow, and the localization parameter was introduced to avoid errors in the flowmeter readings caused by liquid acceleration or deceleration around the electrodes. These parameters were also calculated from the computed velocity and virtual potential fields. The results can be used to obtain the liquid mean velocity from the slug flow signal measured by a current-sensing flowmeter.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1982.05a
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• pp.15.2-15
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• 1982

Inverted papilloma arising from mucous membrane of the nasal cavity and paranasal sinuses is very rare benign neoplasm. Ward first described nasal papilloma in 1854, but its infrequent occurrence has delayed accurate understanding. This tumor was histologically benign neoplasm and clinically malignant, because it is locally invasive with extensive bone erosion at times and it shows a high incidence of local recurrence, and change of squamous cell carinoma was sometimes found. Recently, the authors have experienced a case of inverted pailloma with focal squamous cell carcinoma change which occupied the right side of the nsal cavity and maxillary sinus in a 48-year-old male. The tumor mass was removed surgically through intranasal and Caldwell-Luc's approach, and then was treated with systemic administration of Bleomycin, local spray of 5-FU and radiotherapy ($Co^{60}$). We report our case with review of current literatures.

• Journal of the Korean Magnetics Society
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• v.15 no.4
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• pp.217-220
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• 2005

The electronic structure and magnetism of Fe chain along the [110] direction on Ag(001) were investigated by using the all-electron full-potential linearized augmented plane wave (FLAPW) method within generalized gradient approximation (GGA). The magnetic moment of Fe atom in Fe chain is calculated to be $3.02\;{\mu}_B$, which is slightly larger than that ($2.99\;{\mu}_B$) of the Fe[110] chain on Cu(001). The reduced coordination number for the Fe chain induced the Fe-d band narrowing and exchange-splitting enhancement, which are responsible for the large magnetic moment of the Fe chain. The calculated band width of the Fe-d band and the exchange-splitting are 1.7 eV and 3.2 eV, respectively.

• Childhood Kidney Diseases
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• v.11 no.1
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• pp.100-105
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• 2007

Cockayne syndrome is a rare autosomal recessive disorder characterized by cachectic dwafism, mental retardation, loss of facial subcutaneous adipose tissue, microcephaly and photosensitive dermatitis. It is associated with renal abnormalities characterized by hyalinization of glomeruli, atrophy of tubules and interstitial fibrosis. To our knowledge, this is the first report of a case of Cockayne syndrome with FSGS in Korea. A 7-year old boy was admitted for evaluation of hypertension and proteinuria, which were detected 2 month ago. He was followed for short stature(<3 percentile), mental retardation(IQ 55), strabismus and dental caries since 3 years ago. He also showed microcephaly, a bird-like face and relatively large hands and feet. Laboratory findings showed decreased creatinine clearance($C_{Cr}$ 76.1 mL/min/$1.73m^2$) and proteinuria(1,548 mg/day). Renal biopsy demonstrated focal segmental glomerulosclerosis of the hilar type with large hyaline deposits, moderate tubular atrophy and interstitial fibrosis. His cardinal features, mental retardation, and renal biopsy findings were consistent with Cockayne syndrome. We report here a very rare case of Cockayne syndrome with FSGS presenting with proteinuria and hypertension.