• Journal of the Korea Computer Graphics Society
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• v.24 no.4
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• pp.29-38
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• 2018

In this paper, we propose an automatic segmentation method of meniscus in knee MR images by automatic meniscus localization, multi-atlas-based locally-weighted voting, and patch-based edge feature classification. First, after segmenting the bone and knee articular cartilage, the volume of interest of the meniscus is automatically localized. Second, the meniscus is segmented by multi-atlas-based locally-weighted voting taking into account the weights of shape and intensity distribution in the volume of interest of the meniscus. Finally, to remove leakage to the collateral ligaments with similar intensity, meniscus is refined using patch-based edge feature classification considering shape and distance weights. Dice similarity coefficient between proposed method and manual segmentation were 80.13% of medial meniscus and 80.81 % for lateral meniscus, and showed better results of 7.25% for medial meniscus and 1.31% for lateral meniscus compared to the multi-atlas-based locally-weighted voting.

• Smart Structures and Systems
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• v.11 no.5
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• pp.435-451
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• 2013

High-rise buildings are a common feature of urban cities around the world. These flexible structures frequently exhibit large vibration due to strong winds and earthquakes. Structural control has been employed as an effective means to mitigate excessive responses; however, structural control mechanisms that can be used in tall buildings are limited primarily to mass and liquid dampers. An attractive alternative can be found in outrigger damping systems, where the bending deformation of the building is transformed into shear deformation across dampers placed between the outrigger and the perimeter columns. The outrigger system provides additional damping that can reduce structural responses, such as the floor displacements and accelerations. This paper investigates the potential of using smart dampers, specifically magnetorheological (MR) fluid dampers, in the outrigger system. First, a high-rise building is modeled to portray the St. Francis Shangri-La Place in Philippines. The optimal performance of the outrigger damping system for mitigation of seismic responses in terms of damper size and location also is subsequently evaluated. The efficacy of the semi-active damped outrigger system is finally verified through numerical simulation.

• Korean Journal of Food Science and Technology
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• v.53 no.2
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• pp.195-203
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• 2021

Aureobasidium pullulans, a black yeast, produces pullulan, a linear α-glucan composed of maltotriose repeating units linked by α(1→6)-glycosidic linkages. Pullulan can be widely used in food, cosmetic, and biotechnology industries. In this study, we isolated eight strains of A. pullulans from Forsythia koreana, Magnolia kobus DC., Spiraea prunifolia var. simpliciflora, Cornus officinalis, Cerasus, and Hippophae rhamnoides. Among them, A. pullulans MR was selected as the best pullulan producer. The effects of a carbon source, a nitrogen source, and pH on pullulan production were examined. The optimal cultivation conditions for pullulan production by A. pullulans MR were determined by response surface methodology as 15% sucrose, 0.4% soy peptone, and an initial pH of 7 at 26℃. Under these conditions, the predicted pullulan production was 47.6 g/L, which was very close to the experimental data (48.9 g/L).

• Toxicological Research
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• v.21 no.2
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• pp.135-140
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• 2005

Although the pathogenesis of cerebral cavernous malformation (CCM) is unknown, a familial predisposition has been recognized, with up to $55\%$ of patients having an affected relatives. Genetic linkage studies have recently mapped a gene causing CCM to a segment of the long arm of chromosome 7 (7q). We report herein a genetic linkage analysis conducted on a Korean three generation family with CCM. It's first report in Korean family. A Korean family in which one member had undergone surgery for ubtracerebrak hematoma (ICH) and confirmed the CCM, was evaluated. They were examined clinically (n=18) and by magnetic resonance (MR) imaging (n=10). Polymorphic markers (D7S1813, D7S1789) spanning the CCM1 locus on 7q were genotyped by the polymerase chain reaction and analysis of linkage was performed in this family (n=17). Six had multiple lesions on brain MR image, one of them being symptomatic, and five were asymptomatic. Seven remaining members were asymptomatic and refused MR image study. One had died of ICH from presumed CCM. Analysis of the pedigree was consistent with an autosomal dominant pattern of inheritance. All affected patients were linked to CCM1. Linkage to CCM1 can account for inheritance of CCM in this family. They had some striking features with a low clinical penetrance and the presence of multiple lesions. These findings have implications for genetic testing of this disorder and represent an important step toward identification of the gene responsible for the pathogenesis of this disease.

• Smart Structures and Systems
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• v.23 no.1
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• pp.91-106
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• 2019

Adopting sloped rolling-type isolation devices underneath a raised floor system has been proved as one of the most effective approaches to mitigate seismic responses of the protected equipment installed above. However, pounding against surrounding walls or other obstructions may occur if such a base-isolated raised floor system is subjected to long-period excitation, leading to adverse effects or even more severe damage. In this study, real-time hybrid simulation (RTHS) is adopted to assess the control performance of a smart base-isolated raised floor system as it is an efficient and cost-effective experimental method. It is composed of multiple sloped rolling-type isolation devices, a rigid steel platen, four magnetorheological (MR) dampers, and protected high-tech equipment. One of the MR dampers is physically tested in the laboratory while the remainders are numerically simulated. In order to consider the effect of input excitation characteristics on the isolation performance, the smart base-isolated raised floor system is assumed to be located at the roof of a building and the ground level. Four control algorithms are designed for the MR dampers including passive-on, switching, modified switching, and fuzzy logic control. Six artificial spectrum-compatible input excitations and three slope angles of the isolation devices are considered in the RTHS. Experimental results demonstrate that the incorporation of semi-active control into a base-isolated raised floor system is effective and feasible in practice for high-tech industry.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.2
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• pp.224-233
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• 2012

The limiting sequence and relative ratio of lysine (Lys), methionine (Met), and threonine (Thr) for calves about 2 mo of age fed milk replacers (MR) containing soy protein are not clearly defined. The objective of the study was to investigate the effect of supplementing MR containing 22% CP, half from soy protein concentrate (SPC, 40.56% CP, flour) and half from whey proteins, with Lys, Met, and Thr to estimate amino acid (AA) sequence and their relative ratio for calves about 2 mo of age. A method of partial deduction of AA was adopted. Twenty-four newborn calves (half males and half females, $40.7{\pm}0.9$ kg of BW) were fed 1 of 4 MR diets for 56 d (n = 6/diet). The diets were supplemented with all (positive control) or with 2 of the 3 AAs: Lys, Met and Thr, (i.e., PC (22% CP, 2.34% Lys, 0.72% Met and 1.80% Thr), PC-Lys (22% CP, 1.64% Lys, 0.72% Met and 1.80% Thr), PC-Met (22% CP, 2.34% Lys, 0.50% Met and 1.80% Thr), and PC-Thr (22% CP, 2.34% Lys, 0.72% Met and 1.26% Thr)). Calves were fed thrice daily; starter (20% CP, 1.03% Lys, 0.30% Met and 0.69% Thr), hay (3.23% CP, 0.29% Lys, 0.12% Met and 0.23% Thr) and water were offered free choice. Starter and hay were only offered beginning on d 36 (after 5 wk) and d 43 (after 6 wk), respectively. BW, body size and blood samples measures were taken every two weeks. Three-day total collection of feed refusals, feces, and urine were recorded starting at d 33 and d 54 of age, respectively. From the results, the limiting sequence and relative ratio between the 3 AAs in calves with different diet structures were calculated. The limiting sequence of the 3 AAs were ranked as Lys, Met and Thr; the proper ratio was 100:29:70 for MR-only diet and 100:30:60 for diets consisted of MR, starter and hay. Nitrogen digestion and utilization and nutrient digestibility were negatively affected by AA deletion treatments. From the evidence of this experiment, it did not appear that the AA limiting sequence was selectively altered by differences in diet structures such as would be encountered in practice. The relative ratio between the 3 AAs varied with the offer of starter and hay to calves, and the average ratio was 100:29.5:65 for calves during 2 to 10 wk of age.

• Korean Journal of Radiology
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• v.20 no.4
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• pp.641-648
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• 2019

Objective: The purpose of this study was to investigate whether three-dimensional (3D) magnetic resonance imaging could improve diagnostic accuracy for suspected posterior ligamentous complex (PLC) disruption. Materials and Methods: We used 20 freshly harvested goat spine samples with 60 segments and intact surrounding soft tissue. The animals were aged 1-1.5 years and consisted of 8 males and 12 females, which were sexually mature but had not reached adult weights. We created a paraspinal contusion model by percutaneously injecting 10 mL saline into each side of the interspinous ligament (ISL). All segments underwent T2-weighted sagittal and coronal short inversion time inversion recovery (STIR) scans as well as coronal and sagittal 3D proton density-weighted spectrally selective inversion recovery (3D-PDW-SPIR) scans acquired at 1.5T. Following scanning, some ISLs were cut and then the segments were rescanned using the same magnetic resonance (MR) techniques. Two radiologists independently assessed the MR images, and the reliability of ISL tear interpretation was assessed using the kappa coefficient. The chi-square test was used to compare the diagnostic accuracy of images obtained using the different MR techniques. Results: The interobserver reliability for detecting ISL disruption was high for all imaging techniques (0.776-0.949). The sensitivity, specificity, and diagnostic accuracy of the coronal 3D-PDW-SPIR technique for detecting ISL tears were 100, 96.9, and 97.9%, respectively, which were significantly higher than those of the sagittal STIR (p = 0.000), coronal STIR (p = 0.000), and sagittal 3D-PDW-SPIR (p = 0.001) techniques. Conclusion: Compared to other MR methods, coronal 3D-PDW-SPIR provides a more accurate diagnosis of ISL disruption. Adding coronal 3D-PDW-SPIR to a routine MR protocol may help to identify PLC disruptions in cases with nearby contusion.

• Journal of Power Electronics
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• v.17 no.4
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• pp.991-1003
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• 2017

The conventional sliding mode control (CSMC) has a number of problems. It may cause dc output voltage ripple and it cannot guarantee the robustness of the whole system for a matrix rectifier (MR). Furthermore, the existence of a filter can decrease the input power factor (IPF). Therefore, a novel global sliding mode control (GSMC) based on a hyperbolic tangent function with IPF compensation for MRs is proposed in this paper. Firstly, due to the reachability and existence of the sliding mode, the condition of the matrix rectifier's robustness and chattering elimination is derived. Secondly, a global switching function is designed and the determination of the transient operation status is given. Then a SMC compensation strategy based on a DQ transformation model is applied to compensate the decreasing IPF. Finally, simulations and experiments are carried out to verify the correctness and effectiveness of the control algorithm. The obtained results show that compared with CSMC, applying the proposed GSMC based on a hyperbolic tangent function for matrix rectifiers can achieve a ripple-free output voltage with a unity IPF. In addition, the rectifier has an excellent robust performance at all times.

• Investigative Magnetic Resonance Imaging
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• v.26 no.2
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• pp.104-116
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• 2022

The purpose of this study is to systematically determine an optimal percentile cut-off in histogram analysis for calculating the mean parameters obtained from a non-Gaussian continuous-time random-walk (CTRW) diffusion model for differentiating individual glioma grades. This retrospective study included 90 patients with histopathologically proven gliomas (42 grade II, 19 grade III, and 29 grade IV). We performed diffusion-weighted imaging using 17 b-values (0-4000 s/mm²) at 3T, and analyzed the images with the CTRW model to produce an anomalous diffusion coefficient (D_m) along with temporal (𝛼) and spatial (𝛽) diffusion heterogeneity parameters. Given the tumor ROIs, we created a histogram of each parameter; computed the P-values (using a Student's t-test) for the statistical differences in the mean D_m, 𝛼, or 𝛽 for differentiating grade II vs. grade III gliomas and grade III vs. grade IV gliomas at different percentiles (1% to 100%); and selected the highest percentile with P < 0.05 as the optimal percentile. We used the mean parameter values calculated from the optimal percentile cut-offs to do a receiver operating characteristic (ROC) analysis based on individual parameters or their combinations. We compared the results with those obtained by averaging data over the entire region of interest (i.e., 100th percentile). We found the optimal percentiles for D_m, 𝛼, and 𝛽 to be 68%, 75%, and 100% for differentiating grade II vs. III and 58%, 19%, and 100% for differentiating grade III vs. IV gliomas, respectively. The optimal percentile cut-offs outperformed the entire-ROI-based analysis in sensitivity (0.761 vs. 0.690), specificity (0.578 vs. 0.526), accuracy (0.704 vs. 0.639), and AUC (0.671 vs. 0.599) for grade II vs. III differentiations and in sensitivity (0.789 vs. 0.578) and AUC (0.637 vs. 0.620) for grade III vs. IV differentiations, respectively. Percentile-based histogram analysis, coupled with the multi-parametric approach enabled by the CTRW diffusion model using high b-values, can improve glioma grading.

• The Journal of Advanced Prosthodontics
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• v.16 no.4
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• pp.212-220
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• 2024

PURPOSE. This cone-beam computed tomography (CBCT) study aimed to analyze the anatomical characteristics of alveolar bone at mandibular first molar (MFM) and their implications for immediate implant placement surgery. MATERIALS AND METHODS. 100 patients with 140 MFMs were reviewed retrospectively. We first performed a 3D reconstruction of the patient's CBCT data to determine a reference plane with ideal implant placement and orientation. The following parameters of MFM region were analyzed: mesial-distal socket size (MDSS), buccal-lingual socket size (BL-SS), root furcation fornix to inferior alveolar nerve (IAN) distance (RF-I), interradicular bone thickness (IRB), mesial/distal root apex to the IAN distance (MRA-I/DRA-I), thickness of the buccal/lingual bone of the mesial root (MR-B/MR-L), thickness of the buccal/lingual bone of the distal root (DR-B/DR-L). RESULTS. The MD-SS of MFM was 8.74 ± 0.76 mm, and the BLSS was 8.26 ± 0.72 mm. The MR-B, DR-B was 1.01 ± 0.40 mm and 1.14 ± 0.50 mm, and the difference was statistically significant (P = .001). The values of the MR-L, DR-L were 2.71 ± 0.78 mm and 3.09 ± 0.73 mm, and the difference was also statistically significant (P < .001). The mean distance of RF-I was 15.68 ± 2.13 mm, and the MRA-I was 7.06 ± 2.22 mm, which was greater than that of DRA-I (6.48 ± 2.30 mm, P < .001). The IRB at 2 mm, 4 mm apical from the furcation fornix, and at apex level was 2.81 ± 0.50 mm, 3.30 ± 0.62 mm, and 4.44 ± 1.02 mm, respectively. CONCLUSION. There is relatively sufficient bone mass in interradicular bone in height, but an adequate width is lacking for the bone between the mesial and distal root after the extraction of the MFM for immediate implantation. The thickness of the MFM buccal bone is relative thin, especially for the mesial root.