• Journal of Korean Neurosurgical Society
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• v.57 no.2
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• pp.108-113
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• 2015

Objective : Although the L5-S1 has distinct structural features in comparison with other lumbar spine segments, not much is known about adjacent segment degeneration (ASD) at the L5-S1 segment. The aim of study was to compare the incidence and character of ASD of the cephalad and L5-S1 segments after L5 floating lumbar fusion. Methods : From 2005 to 2010, 115 patients who underwent L5 floating lumber fusion were investigated. The mean follow-up period was 46.1 months. The incidence of radiological and clinical ASD of the cephalad and the L5-S1 segments was compared using survival analysis. Risk factors affecting ASD were analyzed using a log rank test and the Cox proportional hazard model. Results : Radiological ASD of the L5-S1 segment had a statistically significant higher survival rate than that of the cephalad segment (p=0.001). However, clinical ASD of the L5-S1 segment was significantly lower survival rates than that of the cephalad segment (p=0.038). Risk factor analysis showed that disc degeneration of the cephalad segment and preoperative spinal stenosis of the L5-S1 segment were risk factors. Conclusion : In L5 floating fusion, radiological ASD was more common in the cephalad segment and clinical ASD was more common in the L5-S1 segment. At the L5-S1 segment, the degree of spinal stenosis appears to be the most influential risk factor in ASD incidences, unlike the cephalad segment.

• Korean Journal of Veterinary Research
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• v.30 no.4
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• pp.383-394
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• 1990

The gastrointestinal endocrine cells of the Pond tortoise, Amyda sinensis were studied immunohistochemically, and somatostatin-, gastrin/cholecystokinin(GAS/CCK)-, glucagon-, 5-hydroxytryptamine(5-HT)-, insulin- and chromogranin-immunoreactive cells were revealed. The characteristic findings of the regional distribution and relative frequency of these immunoreative cells in the gastrointestinal tract of the Pond tortoise were as follows; A few somatostatin-immunoreactive cells were distributed from the segment I to the segment V. GAS/CCK-immunoreactive cells were found from the segment III to the segment VII. These cells were numerous in the segment III and a few in the other segments. A few glucagon-immunoreactive cells were found in the segment I and rare in the segment II. 5-HT-immunoreactive cells were found throughout the gastrointestinal tract. Numerous numbers of them were found in the segment I, while moderate or a few in the other segments. Insulin-immunoreactive cells were distributed from the segment II to the segment IX. Moderate numbers of them were found in the segment VIII and IX, while a few in the other segments. Chromogranin-immunoreactive cells were found from the segment III to the segment VI. Moderate numbers of these cells were found in the segment IV and V, while a few in the other segments. BPP-immunoreactive cells were not observed throughout the gastrointestinal tract of the Pond tortoise, Amyda sinensis.

• Physical Therapy Korea
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• v.10 no.1
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• pp.63-76
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• 2003

This research was performed to compare spinal segment motion angle between low back pain (LBP) group and painless group during trunk flexion-extension and to investigate the effect of transversus abdominis strengthening exercise on spinal segment motion angle in LBP group. Nine subjects with LBP and ten subjects without LBP participated. Transversus abdominis strengthening exercise was performed in LBP group for three weeks, and spinal segment motion angles were compared before and after the exercise performance. Spinal segment motion angles were measured both in sitting and standing position. Results were as followed: 1) Subjects' average age was 24.79 years, height was 167.84 cm, and weight was 59.95 kg. 2) Spinal segment motion angle of T10/l1 was significantly higher in LBP group compared with painless group (p<.05) in sitting position during trunk flexion-extension. 3) In sitting position, whereas entire lumbar segment motion angles were lower in LBP group compared with painless group (p<.05), angle of L4/5 was higher in LBP group compared with painless group (p<.05). 4) There was no significant difference in thoracic segment motion angle in standing position. 5) After three weeks of transversus abdominis strengthening exercise, thoracic segment motion angle increased both in sitting and standing position (p<.05). 6) In painless group, there was no significant difference in entire spinal segment motion angles in sitting and standing position (p>.05). When spinal segment motion angles were compared between sitting and standing position, there were slight differences. In sitting position, there was no difference in spinal segment motion angle between LBP group and painless group while hip joint motion angle and sacral inclination angle of LBP group was lower than those of painless group (p<.05). In standing position, lumbar segment motion angle was significantly lower in LBP group than that of painless group. Transversus abdominis strengthening exercise influenced thoracic segment motion angle more significantly than lumbar segment motion angle.

• Polymer(Korea)
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• v.31 no.6
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• pp.543-549
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• 2007

We synthesized various polyurethanes(PU) haying different hard segments with different molecular weights of the soft segment to explore the effect of structure on the dispersion of silver particle in the phase of synthesized polyurethanes matrix. The thermal stability was increased by increasing the number of aromatic compound, while the degree of dispersion for silver particle was decreased. Silver particles showed better dispersion in the PU matrix having aromatic compounds when the soft segments were held constant. On the contrary, when the hard segment was held constant, silver particles on the PU matrix haying low $M_w$ of soft segment showed better dispersion than high $M_w$ of soft segment because poor chain mobility of low $M_w$ of soft segment restricted re-aggregation of silver particle. A sheet resistance of composite materials showed different aspects. In this case, the inter connection between silver particles was more important than its dispersion. In this study, the NDI-PEG 900/silver particle composite film showed the best thermal stability and electro conductivity.

• Journal of Information Processing Systems
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• v.16 no.2
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• pp.406-420
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• 2020

In order to make up the deficiencies of the existing research results which cannot effectively deal with the nearest neighbor query based on the line segments in obstacle space, the k nearest neighbor query method of line segment in obstacle space is proposed and the STA_OLkNN algorithm under the circumstance of static obstacle data set is put forward. The query process is divided into two stages, including the filtering process and refining process. In the filtration process, according to the properties of the line segment Voronoi diagram, the corresponding pruning rules are proposed and the filtering algorithm is presented. In the refining process, according to the relationship of the position between the line segments, the corresponding distance expression method is put forward and the final result is obtained by comparing the distance. Theoretical research and experimental results show that the proposed algorithm can effectively deal with the problem of k nearest neighbor query of the line segment in the obstacle environment.

• Journal of Korean Neurosurgical Society
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• v.59 no.2
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• pp.129-136
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• 2016

Objective : The purpose of this study was to figure out the radiologic findings and risk factors related to adjacent segment degeneration (ASD) after anterior cervical discectomy and fusion (ACDF) using 3-year follow-up radiography, computed tomography (CT), and magnetic resonance image (MRI). Methods : A retrospective matched comparative study was performed for 64 patients who underwent single-level ACDF with a cage and plate. Radiologic parameters, including upper segment range of motion (USROM), lower segment range of motion (LSROM), upper segment disc height (UDH), and lower segment disc height (LDH), clinical outcomes assessed with neck and arm visual analogue scale (VAS), and risk factors were analyzed. Results : Patients were categorized into the ASD (32 patients) and non-ASD (32 patients) group. The decrease of UDH was significantly greater in the ASD group at each follow-up visit. At 36 months postoperatively, the difference for USROM value from the preoperative one significantly increased in the ASD group than non-ASD group. Preoperative other segment degeneration was significantly associated with the increased incidence of ASD at 36 months. However, pain intensity for the neck and arm was not significantly different between groups at any post-operative follow-up visit. Conclusion : The main factor affecting ASD is preoperative other segment degeneration out of the adjacent segment. In addition, patients over the age of 50 are at higher risk of developing ASD. Although there was definite radiologic degeneration in the ASD group, no significant difference was observed between the ASD and non-ASD groups in terms of the incidence of symptomatic disease.

• Phonetics and Speech Sciences
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• v.2 no.4
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• pp.59-65
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• 2010

In this paper, we investigate acoustic characteristics of Korean /s/ when it is followed by both a high front and a round segment regardless of their order to one another. We show that Korean /s/ in this environment has characteristics of a labio-palatalized segment, being affected by both a high front and a round segment if they occur within the domain of a syllable. In the experiment, we show that Korean /s/ before a high front and a round segment shows a spectral shape different from that in other environments. Specifically, it is different from /s/ before a high front segment only, showing peaks around 2.5 kHz. Furthermore, it shows a rapid decrease of amplitude in 4-5 kHz, and sometimes another plateau of high peaks in 5-6 kHz. We also examined center of gravity frequency and band energy difference. Based on the results of this experiment, we argue that Korean /s/ is affected by the following segments within the domain of coarticulation, a syllable and that the degree of coarticulation is different from language to language.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.3
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• pp.99-105
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• 2011

In this paper, we proposed a method for estimating an accurate gamut based on segment maxima method. According to the number of segments in the segment maxima, a local concavity is generated in the vicinity of lightness axis or a gamut is reduced in high chroma region. It induces artifacts or deterioration of the image quality. To remove these artifacts, the number of segment is determined according to the number of samples. and a local concavity is modified by extending a detected concave point to the line connecting two adjacent boundary points. Experimental results show that the contours in a uniform color region and speckle artifacts from the conventional segment maxima algorithm are removed.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.6
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• pp.695-702
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• 2015

Recently, the improvement of mechanical and theoretical issues in geo-centrifuge test enhances the applicability and accuracy of the test. Geo-centrifuge test is appropriate to simulate the behaviors of underground structures like tunnel, since tunnel interacts with the soil and/or rock around it and the test can embody the in-situ stress conditions effectively. In this study, the seismic behaviors of twin tunnel were analyzed based on geo-centrifuge test. Flexible segment to mitigate seismic acceleration were implemented in the model with thin and thick thickness. Based on the test results, it was found that flexible segment can decrease the peak acceleration generally, however, thin flexible segment was not able to reduce peak acceleration in short-period seismic wave. Thick flexible segment was more effective in case of high bedrock acceleration condition. Additionally, 3-dimensional numerical analysis was performed to verify the characteristics of seismic behavior and the effect of flexible segment. Consequently, the numerical analysis result showed good agreement with the test result.

• Journal of Korean Neurosurgical Society
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• v.41 no.2
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• pp.88-94
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• 2007

Objective : The aim of this study is to investigate predictable risk factors for radiologic degeneration of adjacent segment after lumbar fusion and preoperative radiologic features of patients who underwent additional surgery with adjacent segment degeneration. Methods : Between January 1995 and December 2002, 201 patients who underwent lumbar fusion for degenerative conditions of lumbar spine were evaluated. We studied radiologic features, the method of operation, the length of fusion, age, sex, osteoporosis, and body mass index. Special attention was focused on, preoperative radiologic features of patients who required additional surgery were studied to detect risk factors for clinical deterioration. Results : Follow-up period ranged from 3 to 11 years. In our study, 61 [30%] patients developed adjacent segment degeneration, and 15 [7%] patients required additional surgery for neurologic deterioration. Age, the postoperative delay, facet volume, motion range, laminar inclination, facet tropism, and preexisting disc degeneration of adjacent segment considered as possible risk factors. Among these, laminar inclination and preexisting disc degeneration of adjacent segment were significantly correlated with clinical deterioration. Conclusion : The radiologic degeneration of adjacent segment after lumbar fusion can be predicted in terms of each preoperative radiologic factor, age and the postoperative delay. Laminar inclination and preexisting disc degeneration of adjacent segment have shown as strong risk factors for neurologic deterioration. Thus, careful consideration is warranted when these risk factors are present.