2019 IEEE International Conference on Computational Science and Engineering (CSE) and IEEE International Conference on Embedded and Ubiquitous Computing (EUC)
We present a lightweight convolutional neural network model for street view house numbers recogni... more We present a lightweight convolutional neural network model for street view house numbers recognition and classification. Our ultimate goal is to build a high performance, compact and memory efficient deep learning model for classifying digits of real-wo
A 3D stereoscopic image is generated by interdigitating every scene with video editing tools that... more A 3D stereoscopic image is generated by interdigitating every scene with video editing tools that are rendered by two cameras' views in 3D modeling tools, like Autodesk MAX® and Autodesk MAYA®. However, the depth of object from a static scene and the continuous stereo effect in the view of transformation, are not represented in a natural method. This is because after choosing the settings of arbitrary angle of convergence and the distance between the modeling and those two cameras, the user needs to render the view from both cameras. So, the user needs a process of controlling the camera's interval and rendering repetitively, which takes too much time. Therefore, in this paper, we will propose the 3D stereoscopic image editing system for solving such problems as well as exposing the system's inherent limitations. We can generate the view of two cameras and can confirm the stereo effect in real-time on 3D modeling tools. Then, we can intuitively determine immersion of 3D stereoscopic image in real-time, by using the 3D stereoscopic image preview function.
Recently, while 3D sports game increases, the research that it recognizes the operation of the re... more Recently, while 3D sports game increases, the research that it recognizes the operation of the real user actively progresses. Most of all, the research about the golf is active. In this paper, the camera acquiring in a high-speed multi-exposure image measures the flight data of the golf ball through the image processing. While photographing, the high-speed camera, using this system, exposes an image at regular intervals. And line scan camera checks whether the golf ball passed or not. After the location information of the calculated golf ball calculates a speed and a direction by using the physical formula, it applies the golf simulation. After, this system is possible the measurement of the physical element of the spherical object.
This study was carried out to evaluate ecological growth characteristics of forty castor bean col... more This study was carried out to evaluate ecological growth characteristics of forty castor bean collections for biodiesel utilization. The emergence date and it's rate of collections was 15-16 days and 82.5%, respectively. It took 63-68 days from emergence to flowering. Stem length was ranged from 173 to 251 cm with an average 211.8 cm. The average stem diameter was 24.2 cm, and showed the high occurrence as 52.5% at the 20.4-24.9 cm. The node number was widely distributed as 13-22 and the average node number was 18.9. The seed numbers were widely distributed as 7-33ea, and the average liter weight of seed was 502.9 g of which minimum weight was 432.3 g and maximum weight was 572.5 g, and the gap between maximum and minimum was 140.2 g. It showed high difference. The 100 grain weight was distributed as 20.3 g-38.3 g which showed high differences between small grain and large grain collections. The seed numbers per plant were varied as 72 at the minimum and 1,011 at the maximum number, and average seed number was 465.2. The total yields of seed per plant were varied as 20 g-266.2 g, and the average yields were 128.1 g.
Journal of the Korea Industrial Information System Society, 2015
In recent years, the advance on the high-end converging technology has improved to the changes on... more In recent years, the advance on the high-end converging technology has improved to the changes on digital signage technology in many ways. Digital signage has to be designed to give information through systemed structure among the constituent for developing the information delivery responding to the environmental conversion, not feeding user information. Therefore, this paper proposes a smart contents platform which supplies various from of digital signage contents. In the digital signage circumstance, the smart contents platform is a way for an effective information transmission, game and the advertising interface by recognizing user interaction and the environmental information. This platform is composed of base hardware, middleware and middle device. Each component module is managed by the smart contents platform. Furthermore, it serves various live contents experiences via gathering and analyzing user and environmental information with linking various sensors and devices. It is a new way of information delivery which serves contents producing and providing circumstances in parallel.
The coefficient of lateral stress at rest K 0 is a state soil variable, yet is well correlated to... more The coefficient of lateral stress at rest K 0 is a state soil variable, yet is well correlated to strength. As different types of friction angles can be defined, it is important to examine the applicability of K 0-strength correlation and further clarify the mechanism of K 0-stress state. In this study, the values of K 0 were experimentally investigated for different types of granular materials, focusing on its correlation to material strength and the effect of particle shape and surface roughness. For this purpose, laboratory tests were conducted to directly measure K 0 of natural sand, spherically shaped glass bead, and surface-etched glass bead packings under various stress and soil conditions. Triaxial and other basic property tests were also conducted to characterize the test granular materials. It was revealed that the effect of material density on K 0 differed depending on the stress history whereas the effect of particle surface roughness, within the range considered in this study, was relatively small. Test results highlight that the values of the friction angle employed into Jaky's K 0 equation to match measured K 0 values are not unique, showing a statedependent aspect. Inter-particle stress analysis was introduced to assess the correlation of K 0 to the friction angle as postulated by Jaky's K 0 equation.
We propose FTIR (Frustrated Total Internal Reflection) based on the multi-touch display system fo... more We propose FTIR (Frustrated Total Internal Reflection) based on the multi-touch display system for playing the AR (Augmented Reality) card game. Existing card games request simple input in the form of a button to interact with a user and to show information that varies with the information or the position of the card. In order to overcome the limitation of these interactions, we present a tangible user interface by applying the multi-touch screen system which can input the pattern of the various forms. In this way we can offer more
International Journal of Advanced Computer Science and Applications, 2013
Nowadays interactive displays are capable of offering a great variety of interactions to users th... more Nowadays interactive displays are capable of offering a great variety of interactions to users thanks to advancement of ubiquitous computing technologies. Although many methods of interactions have been researched, usability of the devices is still limited and they are offered only to a single user at a time. This paper proposes a spatial multi-interaction interface that can provide various interactions to many users in an ambient environment. An interaction surface is created for users to interact through IR-LEDs Array Bar. The coordinate information of the hand is extracted by detecting the area of the hand of a user in the interaction surface. Then users can experience various interactions through "spatial touches" on the interaction surface. In our paper a usability evaluation is carried out for our new interface which gives the emphasis to the interaction interface. The usability of our new interface is shown to be significantly better through statistical testing using t-testing. Finally, users can perform various interactions with natural hand motions only without the aid of devices that have to be operated manually.
The purpose of this study was to evaluate whether bright vessel appearance on arterial spin label... more The purpose of this study was to evaluate whether bright vessel appearance on arterial spin labeling (ASL) MRI can help localize arterial occlusion sites in patients with acute ischemic stroke. Patients who underwent MRI for suspected acute ischemic stroke, as identified by an area of restricted diffusion, were included. All images were visually analyzed for the presence or absence of (1) arterial occlusion on time-of-flight MR angiography, (2) bright vessel appearance on ASL images, and (3) susceptibility vessel sign. McNemar 2-tailed test was used to compare the sensitivities of ASL and susceptibility-weighted imaging for the detection of arterial occlusion, using MR angiography as the reference standard. ASL bright vessel appearance was significantly more common in the group with occlusion than in the group without occlusion (94% [33 of 35] versus 21% [17 of 82], respectively; P<0.001). The bright vessel appearance, when present, was seen proximal or distal to the occlusion si...
Background: Non-alcoholic fatty liver disease is common in patients with insulin resistance. Ster... more Background: Non-alcoholic fatty liver disease is common in patients with insulin resistance. Sterol regulatory element binding protein-1c (SREBP-1c) is a member of a family of transcription factors that have been recognized as key regulators for lipid accumulation in the liver that activate enzymes involved in the fatty acid biosynthetic pathway. This study was designed to evaluate whether alpha-lipoic acid (ALA) inhibits insulin-stimulated SREBP-1c expression. Methods: We investigated the effects of ALA on insulin-stimulated SREBP-1c expression in a human hepatoma cell line (HepG2 cells) using Northern and Western blot analysis. We also examined the effect of ALA on the promoter activity of the SREBP-1c gene to examine whether ALA can affect SREBP-1c expression at the transcriptional level. To discern the mechanism by which ALA inhibits SREBP-1c expression, we examined the role of AMP-activated protein kinase (AMPK). Results: Insulin increased the expression of SREBP-1c mRNA and protein in HepG2 cells in a dose depended manner. Co-treatment with ALA inhibited the insulin increased SREBP-1c expression in a dose-dependent manner. ALA also inhibited insulin-stimulated activation of the SREBP-1c promoter activity, indicating that ALA inhibited SREBP-1c expression at the transcriptional level. ALA increased phosphorylation of AMPK in HepG2 cells. Inhibition of the AMPK activity by compound C markedly reversed the inhibitory effects of ALA for insulin-stimulated SREBP-1c expression. These results suggest that ALA-induced suppression of SREBP-1c expression is at least in part mediated via AMPK activation. Conclusion: The present study suggests that ALA has an inhibitory effect on insulin-stimulated SREBP-1c expression. Therefore, further studies on the effects of ALA on hepatic steatosis in an animal model need to be performed.
Background: The highly developed endoplasmic reticulum (ER) structure is one of the characteristi... more Background: The highly developed endoplasmic reticulum (ER) structure is one of the characteristic features of pancreatic β-cells. Recent study showed that ER stress causes β-cell dysfunction. However, little is known about the effects of high glucose concentration on induction of ER stress in pancreatic β-cells. Therefore, this study was designed to evaluate whether exposure of high glucose concentration in rat insulinoma cell line, INS-1 cell induces ER stress and whether ER stress decreases insulin gene expression. Methods: The effect of 30 mM glucose on insulin expression and secretion in INS-1 cells was evaluated by Northern blot analysis and glucose-stimulated insulin secretion (GSIS). Cell viability was evaluated by XTT assay. The effect of 30 mM glucose on phosphorylation of eIF2α and CHOP expression, which are markers of ER stress were evaluated by Western blot analysis. RT-PCR analysis was performed to determine whether high glucose concentration induces XBP-1 splicing. To investigate whether ER stress decreases insulin gene expression, the effect of tunicamycin on insulin mRNA expression was evaluated by Northern blot analysis. Results: The prolonged exposure of INS-1 cells with the 30 mM glucose concentration decreased insulin mRNA expression in a time dependent manner and impaired GSIS while did not influence on cell viability. 30 mM glucose increased phosphorylation of eIF2α, XBP-1 splicing and CHOP expression in INS-1 cells. Tunicamycin-treated INS-1 increased XBP-1 splicing and decreased insulin mRNA expression in a dose dependent manner. Conclusion: This study showed that prolonged exposure of INS-1 with high glucose concentration induces ER stress and ER stress decreases insulin gene expression. Further studies about underlying molecular mechanism by which ER stress induces β-cell dysfunction are needed.
The Journal of Thoracic and Cardiovascular Surgery, 2010
Objective: Efficacy of the maze procedure for atrial fibrillation associated with advanced mitral... more Objective: Efficacy of the maze procedure for atrial fibrillation associated with advanced mitral disease not amenable to repair has not been determined. This study investigated whether type of mitral surgery affects maze outcome. Methods: From January 1999 to January 2007, a total of 435 patients underwent the maze procedure and concomitant mitral operation. Of these, 226 underwent mitral repair and 209 underwent mitral replacement. Results: Median follow-up was 40.6 months (0.4-111.3 months), with 25 deaths and 6 strokes. Nineteen patients did not regain normal sinus rhythm. There were no significant intergroup differences in survival, stroke incidence, or sinus rhythm restoration rate. Among 427 early survivors, 64 had late atrial fibrillation recurrence. Five-year atrial fibrillation-free rates were 80.9% AE 3.7% in the repair group and 77.3% AE 4.1% in the replacement group (P ¼ .099). By multivariate analysis, age at surgery older than 60 years (P ¼ .045), fine atrial fibrillation wave pattern (P ¼ .033), and preoperative left atrial dimension greater than 60 mm (P ¼ .019) were independent risk factors for atrial fibrillation recurrence, whereas type of mitral surgery was not (P ¼ .573). Although transmitral A-wave prevalence did not differ significantly between groups beyond the early postoperative period, A-wave velocity was faster in the repair group through the entire postoperative period (P < .001). Conclusions: Maze outcomes were acceptable regardless of type of mitral surgery. Late atrial fibrillation recurrence was mainly affected by age, unfavorable electrocardiographic characteristics of atrial fibrillation, and larger preoperative left atrial size.
The physical characteristics of hydrate-bearing sediments sampled by pressure coring from the Ull... more The physical characteristics of hydrate-bearing sediments sampled by pressure coring from the Ulleung Basin in the Sea of Japan (East Sea) were investigated using an instrumented chamber capable of testing recovered natural sediments that have never left the methane hydrate stability field. The heterogeneous distribution of segregated hydrate veins and lens structures in sediments results in highly variable geophysical and geomechanical properties. The scaled production test was conducted by controlled depressurization of pressure cores while dissociation and gas production were concurrently monitored using various sensors in the instrumented chamber. The hydrate saturation was estimated to be ∼19.5% in the pore space. Data show a sharp reduction in sediment shear and bulk stiffnesses during hydrate dissociation. Relatively fast gas migration was observed, probably along high-conduction planes left behind as hydrate veins dissociated. The spatial distribution of hydrates in sediment was analyzed based on 3-D image processing. The phenomena relevant to the production test and sampling effects during pressure coring are discussed.
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2011
Although the clinical applications of (18)F-FDG PET/CT and diffusion-weighted MRI (DWI) are simil... more Although the clinical applications of (18)F-FDG PET/CT and diffusion-weighted MRI (DWI) are similar to each other in head and neck cancer, the image acquisition methods in the 2 modalities are significantly different. (18)F-FDG PET/CT traces glucose metabolism, a nonspecific process essential for tumor growth. On the other hand, DWI provides information on Brownian motion of water molecules in tissues, which represents cellularity. The aim of our study was to investigate whether apparent diffusion coefficient (ADC) values at b = 1,000 (ADC(1,000)) and 2,000 (ADC(2,000)) s/mm(2) or whether the change (ADC(ratio)) of ADC values from b = 1,000 to 2,000 s/mm(2) has any significant correlation with the standardized uptake value (SUV) in patients with head and neck squamous cell carcinoma (HNSCC).
2019 IEEE International Conference on Computational Science and Engineering (CSE) and IEEE International Conference on Embedded and Ubiquitous Computing (EUC)
We present a lightweight convolutional neural network model for street view house numbers recogni... more We present a lightweight convolutional neural network model for street view house numbers recognition and classification. Our ultimate goal is to build a high performance, compact and memory efficient deep learning model for classifying digits of real-wo
A 3D stereoscopic image is generated by interdigitating every scene with video editing tools that... more A 3D stereoscopic image is generated by interdigitating every scene with video editing tools that are rendered by two cameras' views in 3D modeling tools, like Autodesk MAX® and Autodesk MAYA®. However, the depth of object from a static scene and the continuous stereo effect in the view of transformation, are not represented in a natural method. This is because after choosing the settings of arbitrary angle of convergence and the distance between the modeling and those two cameras, the user needs to render the view from both cameras. So, the user needs a process of controlling the camera's interval and rendering repetitively, which takes too much time. Therefore, in this paper, we will propose the 3D stereoscopic image editing system for solving such problems as well as exposing the system's inherent limitations. We can generate the view of two cameras and can confirm the stereo effect in real-time on 3D modeling tools. Then, we can intuitively determine immersion of 3D stereoscopic image in real-time, by using the 3D stereoscopic image preview function.
Recently, while 3D sports game increases, the research that it recognizes the operation of the re... more Recently, while 3D sports game increases, the research that it recognizes the operation of the real user actively progresses. Most of all, the research about the golf is active. In this paper, the camera acquiring in a high-speed multi-exposure image measures the flight data of the golf ball through the image processing. While photographing, the high-speed camera, using this system, exposes an image at regular intervals. And line scan camera checks whether the golf ball passed or not. After the location information of the calculated golf ball calculates a speed and a direction by using the physical formula, it applies the golf simulation. After, this system is possible the measurement of the physical element of the spherical object.
This study was carried out to evaluate ecological growth characteristics of forty castor bean col... more This study was carried out to evaluate ecological growth characteristics of forty castor bean collections for biodiesel utilization. The emergence date and it's rate of collections was 15-16 days and 82.5%, respectively. It took 63-68 days from emergence to flowering. Stem length was ranged from 173 to 251 cm with an average 211.8 cm. The average stem diameter was 24.2 cm, and showed the high occurrence as 52.5% at the 20.4-24.9 cm. The node number was widely distributed as 13-22 and the average node number was 18.9. The seed numbers were widely distributed as 7-33ea, and the average liter weight of seed was 502.9 g of which minimum weight was 432.3 g and maximum weight was 572.5 g, and the gap between maximum and minimum was 140.2 g. It showed high difference. The 100 grain weight was distributed as 20.3 g-38.3 g which showed high differences between small grain and large grain collections. The seed numbers per plant were varied as 72 at the minimum and 1,011 at the maximum number, and average seed number was 465.2. The total yields of seed per plant were varied as 20 g-266.2 g, and the average yields were 128.1 g.
Journal of the Korea Industrial Information System Society, 2015
In recent years, the advance on the high-end converging technology has improved to the changes on... more In recent years, the advance on the high-end converging technology has improved to the changes on digital signage technology in many ways. Digital signage has to be designed to give information through systemed structure among the constituent for developing the information delivery responding to the environmental conversion, not feeding user information. Therefore, this paper proposes a smart contents platform which supplies various from of digital signage contents. In the digital signage circumstance, the smart contents platform is a way for an effective information transmission, game and the advertising interface by recognizing user interaction and the environmental information. This platform is composed of base hardware, middleware and middle device. Each component module is managed by the smart contents platform. Furthermore, it serves various live contents experiences via gathering and analyzing user and environmental information with linking various sensors and devices. It is a new way of information delivery which serves contents producing and providing circumstances in parallel.
The coefficient of lateral stress at rest K 0 is a state soil variable, yet is well correlated to... more The coefficient of lateral stress at rest K 0 is a state soil variable, yet is well correlated to strength. As different types of friction angles can be defined, it is important to examine the applicability of K 0-strength correlation and further clarify the mechanism of K 0-stress state. In this study, the values of K 0 were experimentally investigated for different types of granular materials, focusing on its correlation to material strength and the effect of particle shape and surface roughness. For this purpose, laboratory tests were conducted to directly measure K 0 of natural sand, spherically shaped glass bead, and surface-etched glass bead packings under various stress and soil conditions. Triaxial and other basic property tests were also conducted to characterize the test granular materials. It was revealed that the effect of material density on K 0 differed depending on the stress history whereas the effect of particle surface roughness, within the range considered in this study, was relatively small. Test results highlight that the values of the friction angle employed into Jaky's K 0 equation to match measured K 0 values are not unique, showing a statedependent aspect. Inter-particle stress analysis was introduced to assess the correlation of K 0 to the friction angle as postulated by Jaky's K 0 equation.
We propose FTIR (Frustrated Total Internal Reflection) based on the multi-touch display system fo... more We propose FTIR (Frustrated Total Internal Reflection) based on the multi-touch display system for playing the AR (Augmented Reality) card game. Existing card games request simple input in the form of a button to interact with a user and to show information that varies with the information or the position of the card. In order to overcome the limitation of these interactions, we present a tangible user interface by applying the multi-touch screen system which can input the pattern of the various forms. In this way we can offer more
International Journal of Advanced Computer Science and Applications, 2013
Nowadays interactive displays are capable of offering a great variety of interactions to users th... more Nowadays interactive displays are capable of offering a great variety of interactions to users thanks to advancement of ubiquitous computing technologies. Although many methods of interactions have been researched, usability of the devices is still limited and they are offered only to a single user at a time. This paper proposes a spatial multi-interaction interface that can provide various interactions to many users in an ambient environment. An interaction surface is created for users to interact through IR-LEDs Array Bar. The coordinate information of the hand is extracted by detecting the area of the hand of a user in the interaction surface. Then users can experience various interactions through "spatial touches" on the interaction surface. In our paper a usability evaluation is carried out for our new interface which gives the emphasis to the interaction interface. The usability of our new interface is shown to be significantly better through statistical testing using t-testing. Finally, users can perform various interactions with natural hand motions only without the aid of devices that have to be operated manually.
The purpose of this study was to evaluate whether bright vessel appearance on arterial spin label... more The purpose of this study was to evaluate whether bright vessel appearance on arterial spin labeling (ASL) MRI can help localize arterial occlusion sites in patients with acute ischemic stroke. Patients who underwent MRI for suspected acute ischemic stroke, as identified by an area of restricted diffusion, were included. All images were visually analyzed for the presence or absence of (1) arterial occlusion on time-of-flight MR angiography, (2) bright vessel appearance on ASL images, and (3) susceptibility vessel sign. McNemar 2-tailed test was used to compare the sensitivities of ASL and susceptibility-weighted imaging for the detection of arterial occlusion, using MR angiography as the reference standard. ASL bright vessel appearance was significantly more common in the group with occlusion than in the group without occlusion (94% [33 of 35] versus 21% [17 of 82], respectively; P<0.001). The bright vessel appearance, when present, was seen proximal or distal to the occlusion si...
Background: Non-alcoholic fatty liver disease is common in patients with insulin resistance. Ster... more Background: Non-alcoholic fatty liver disease is common in patients with insulin resistance. Sterol regulatory element binding protein-1c (SREBP-1c) is a member of a family of transcription factors that have been recognized as key regulators for lipid accumulation in the liver that activate enzymes involved in the fatty acid biosynthetic pathway. This study was designed to evaluate whether alpha-lipoic acid (ALA) inhibits insulin-stimulated SREBP-1c expression. Methods: We investigated the effects of ALA on insulin-stimulated SREBP-1c expression in a human hepatoma cell line (HepG2 cells) using Northern and Western blot analysis. We also examined the effect of ALA on the promoter activity of the SREBP-1c gene to examine whether ALA can affect SREBP-1c expression at the transcriptional level. To discern the mechanism by which ALA inhibits SREBP-1c expression, we examined the role of AMP-activated protein kinase (AMPK). Results: Insulin increased the expression of SREBP-1c mRNA and protein in HepG2 cells in a dose depended manner. Co-treatment with ALA inhibited the insulin increased SREBP-1c expression in a dose-dependent manner. ALA also inhibited insulin-stimulated activation of the SREBP-1c promoter activity, indicating that ALA inhibited SREBP-1c expression at the transcriptional level. ALA increased phosphorylation of AMPK in HepG2 cells. Inhibition of the AMPK activity by compound C markedly reversed the inhibitory effects of ALA for insulin-stimulated SREBP-1c expression. These results suggest that ALA-induced suppression of SREBP-1c expression is at least in part mediated via AMPK activation. Conclusion: The present study suggests that ALA has an inhibitory effect on insulin-stimulated SREBP-1c expression. Therefore, further studies on the effects of ALA on hepatic steatosis in an animal model need to be performed.
Background: The highly developed endoplasmic reticulum (ER) structure is one of the characteristi... more Background: The highly developed endoplasmic reticulum (ER) structure is one of the characteristic features of pancreatic β-cells. Recent study showed that ER stress causes β-cell dysfunction. However, little is known about the effects of high glucose concentration on induction of ER stress in pancreatic β-cells. Therefore, this study was designed to evaluate whether exposure of high glucose concentration in rat insulinoma cell line, INS-1 cell induces ER stress and whether ER stress decreases insulin gene expression. Methods: The effect of 30 mM glucose on insulin expression and secretion in INS-1 cells was evaluated by Northern blot analysis and glucose-stimulated insulin secretion (GSIS). Cell viability was evaluated by XTT assay. The effect of 30 mM glucose on phosphorylation of eIF2α and CHOP expression, which are markers of ER stress were evaluated by Western blot analysis. RT-PCR analysis was performed to determine whether high glucose concentration induces XBP-1 splicing. To investigate whether ER stress decreases insulin gene expression, the effect of tunicamycin on insulin mRNA expression was evaluated by Northern blot analysis. Results: The prolonged exposure of INS-1 cells with the 30 mM glucose concentration decreased insulin mRNA expression in a time dependent manner and impaired GSIS while did not influence on cell viability. 30 mM glucose increased phosphorylation of eIF2α, XBP-1 splicing and CHOP expression in INS-1 cells. Tunicamycin-treated INS-1 increased XBP-1 splicing and decreased insulin mRNA expression in a dose dependent manner. Conclusion: This study showed that prolonged exposure of INS-1 with high glucose concentration induces ER stress and ER stress decreases insulin gene expression. Further studies about underlying molecular mechanism by which ER stress induces β-cell dysfunction are needed.
The Journal of Thoracic and Cardiovascular Surgery, 2010
Objective: Efficacy of the maze procedure for atrial fibrillation associated with advanced mitral... more Objective: Efficacy of the maze procedure for atrial fibrillation associated with advanced mitral disease not amenable to repair has not been determined. This study investigated whether type of mitral surgery affects maze outcome. Methods: From January 1999 to January 2007, a total of 435 patients underwent the maze procedure and concomitant mitral operation. Of these, 226 underwent mitral repair and 209 underwent mitral replacement. Results: Median follow-up was 40.6 months (0.4-111.3 months), with 25 deaths and 6 strokes. Nineteen patients did not regain normal sinus rhythm. There were no significant intergroup differences in survival, stroke incidence, or sinus rhythm restoration rate. Among 427 early survivors, 64 had late atrial fibrillation recurrence. Five-year atrial fibrillation-free rates were 80.9% AE 3.7% in the repair group and 77.3% AE 4.1% in the replacement group (P ¼ .099). By multivariate analysis, age at surgery older than 60 years (P ¼ .045), fine atrial fibrillation wave pattern (P ¼ .033), and preoperative left atrial dimension greater than 60 mm (P ¼ .019) were independent risk factors for atrial fibrillation recurrence, whereas type of mitral surgery was not (P ¼ .573). Although transmitral A-wave prevalence did not differ significantly between groups beyond the early postoperative period, A-wave velocity was faster in the repair group through the entire postoperative period (P < .001). Conclusions: Maze outcomes were acceptable regardless of type of mitral surgery. Late atrial fibrillation recurrence was mainly affected by age, unfavorable electrocardiographic characteristics of atrial fibrillation, and larger preoperative left atrial size.
The physical characteristics of hydrate-bearing sediments sampled by pressure coring from the Ull... more The physical characteristics of hydrate-bearing sediments sampled by pressure coring from the Ulleung Basin in the Sea of Japan (East Sea) were investigated using an instrumented chamber capable of testing recovered natural sediments that have never left the methane hydrate stability field. The heterogeneous distribution of segregated hydrate veins and lens structures in sediments results in highly variable geophysical and geomechanical properties. The scaled production test was conducted by controlled depressurization of pressure cores while dissociation and gas production were concurrently monitored using various sensors in the instrumented chamber. The hydrate saturation was estimated to be ∼19.5% in the pore space. Data show a sharp reduction in sediment shear and bulk stiffnesses during hydrate dissociation. Relatively fast gas migration was observed, probably along high-conduction planes left behind as hydrate veins dissociated. The spatial distribution of hydrates in sediment was analyzed based on 3-D image processing. The phenomena relevant to the production test and sampling effects during pressure coring are discussed.
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2011
Although the clinical applications of (18)F-FDG PET/CT and diffusion-weighted MRI (DWI) are simil... more Although the clinical applications of (18)F-FDG PET/CT and diffusion-weighted MRI (DWI) are similar to each other in head and neck cancer, the image acquisition methods in the 2 modalities are significantly different. (18)F-FDG PET/CT traces glucose metabolism, a nonspecific process essential for tumor growth. On the other hand, DWI provides information on Brownian motion of water molecules in tissues, which represents cellularity. The aim of our study was to investigate whether apparent diffusion coefficient (ADC) values at b = 1,000 (ADC(1,000)) and 2,000 (ADC(2,000)) s/mm(2) or whether the change (ADC(ratio)) of ADC values from b = 1,000 to 2,000 s/mm(2) has any significant correlation with the standardized uptake value (SUV) in patients with head and neck squamous cell carcinoma (HNSCC).
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Papers by Tae Soo Yun