• Steel and Composite Structures
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• v.50 no.6
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• pp.627-641
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• 2024

This paper presents an experimental and numerical study to investigate the behavior of the precast segmental concrete beams (PSCBs) utilizing high-strength concrete (HSC) connected in the zone of the maximum bending moment using steel extended endplate connections (EECs). The experimental study consisted of five beams as follows: The first beam was the control beam for comparison, which was an unconnected one-piece beam made of HSC. The other four other beams consisted of two identical pieces of precast concrete. An important point to be noted is that at the end of each piece, a steel plate was used with a thickness of 10 mm. Moreover, this steel plate was welded to the lower and upper reinforcing bars of the beam. Furthermore, the steel plate was made to connect the two pieces using the technique of EECs. Several variables were taken in these four beams, whether from the shape of the connection or enhancing the behavior of the connection using the post-tensioning technique. EECs without stiffeners were used for some of the tested beams. The behavior of these connections was improved using stiffeners and shear bolts. To get accurate results, a comparison was made between the behaviors of the five beams. Another important point to be noted is that Abaqus and SAP2000 programs were used to investigate the behavior of PSCBs and to ensure the accuracy of the modeling process which showed a good agreement with the experimental results. Additionally, the simplified modeling using SAP2000 was able to model the nonlinear behavior of PSCBs connected using steel EECs. It was found that the steel pre-tensioned bolted EECs, reinforced with steel stiffeners and shear anchors, could be used to connect the precast HSC segmental beams via the internal pre-stressing technique.

• Journal of the Society of Disaster Information
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• v.20 no.2
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• pp.369-378
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• 2024

Purpose: This study aims to verify structural stability by manufacturing a 40m full-scale specimen composed of a segmental U-shaped PSC girder with integrated tensioning systems and a concrete slab, proceeding dynamic behavior tests, and compare the results of the tests with the results of numerical analysis. Method: Dynamic behavior tests were conducted on a full-scale, undamaged specimen using an impact hammer, and the natural frequency and damping ratio were measured and compared with numerical analysis techniques and the general damping ratio of the facilities. Result: The natural frequency of the numerical analysis model consisting of a girder and slab composite section was calculated to be 2.561Hz, the natural frequency of the full-scale specimen was measured to be 2.670Hz, and the damping ratio was calculated to be 0.42~0.68%. Conclusion: The natural frequency of the full-scale specimen was found to be 4.3% larger than that of the numerical analysis model. Since the masses of the full-scale specimen and the numerical analysis model are the same as 99.97%, it can be derived that the stiffness of the full-scale specimen has secured structural safety and stability. As a result, the dynamic behavior stability of the specimen was verified. The measured damping ratio of 0.42~0.68% was found to be a stable dynamic behavior compared to the PSC structures damping ratio of 0.5~1.0% in the elastic region.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.5
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• pp.811-816
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• 2019

This paper first proposes a technique to separate clean speech signals and mixed noise signals by using an independent vector analysis algorithm of frequency band for 4 channel speech source signals with a noise. An improved output speech signal from the proposed independent vector analysis algorithm is obtained by using the cross-correlation between the signal outputs from the frequency domain delay-sum beamforming and the output signals separated from the proposed independent vector analysis algorithm. In the experiments, the proposed algorithm improves the maximum SNRs of 10.90dB and the segmental SNRs of 10.02dB compared with the frequency domain delay-sum beamforming algorithm for the input mixed noise speeches with 0dB and -5dB SNRs including white noise, respectively. Therefore, it can be seen from this experiment and consideration that the speech quality of this proposed algorithm is improved compared to the frequency domain delay-sum beamforming algorithm.

• Journal of Korean Medicine Rehabilitation
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• v.19 no.2
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• pp.289-302
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• 2009

Objectives : This study was performed in order to investigate the relation of body composition analysis and radiological parameter(lumbosacral angle, lumbar lordortic angle, lumbar gravity line). Methods : This study was carried out with the data from comprehensive medical testing. 75 subject aged 20-59 performed the segmental bioelectrical impedance analysis, questionnaire. And lumbosacral angle, lumbar lordortic angle and lumbar gravity line were measured in the standing position x-ray. Then we analyzed the data. Results : Low back pain(LBP) prevalence in high obesity index(Body Mass Index(BMI), Percentage of Body Fat(PBF), Waist Hip Ratio(WHR)) group was higher than LBP prevalence in normal obesity index group(p<0.01). In LBP group, lumbosacral angle, lumbar lordortic angle were significantly lager than Non-LBP group(p<0.001). And 75% of LBP group indicated abnormal lumbar gravity line ratio(0.67 < Normal lumbar gravity line ratio <1.00). When it comes to analyze relation between obesity index and radiological parameter, no-significant change was seen. Conclusions : This study carried as following research after the study on relation of obesity, LBP and trunk muscle strength. Results from this investigation showed positive correlation between obesity and LBP prevalence. But obesity index didn't indicate significant correlation with structural changes of lumbar vertebrae. When considering prior research, trunk muscle strength changes were more related to LBP prevelence in obese people. This results are expected to explain causes of LBP in obese group.

• Childhood Kidney Diseases
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• v.15 no.1
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• pp.38-48
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• 2011

Purpose: Focal segmental glomerulosclerosis (FSGS) is the most common glomerulopathy causing pediatric renal failure. Since specific treatment targeting the etiology and pathophysiology of primary FSGS is yet elusive, the authors explored the pathophysiology of FSGS by transcriptome analysis of the disease using an animal model. Methods: FGS/kist strain, a mouse model of primary FSGS, and RFM/kist strain, as control and the parent strain of FGS/kist, were used. Kidney tissues were harvested and isolated renal cortex was used to extract mRNA, which was run on AB 1700 mouse microarray chip after reverse transcription to get the transcriptome profile. Results: Sixty two genes were differentially expressed in FGS/kist kidney tissue compared to the control. Those genes were related to cell cycle/cell death, immune reaction, and lipid metabolism/vasculopathy, and the key molecules of their networks were TNF, IL-6/4, IFN${\gamma}$, TP53, and PPAR${\gamma}$. Conclusion: This study confirmed that renal cell death, immune system activation with subsequent fibrosis, and lipid metabolism-related early vasculopathy were involved in the pathophysiology of FSGS. In addition, the relevance of methodology used in this study, namely transcriptome profiling, and Korean animal model of FGS/kist was validated. Further study would reveal novel pathophysiology of FSGS for new therapeutic targets.

• Phonetics and Speech Sciences
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• v.6 no.4
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• pp.171-179
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• 2014

Purposes: Speech acceptability means the subjective judgement of listeners regarding the naturalness and normality of the speech. The purpose of this study was to determine the predicting variables for speech acceptabilities of children with cochlear implants. Methods: Twenty seven children with CI participated. They had profound pre-lingual hearing loss without any additional disabilities. The mean of chronological ages was 8;9, and mean of age of implantation was 2;11. Speech samples of reading and spontaneous speech were recorded separately. Twenty college students who were not familiar to the speech of deaf children evaluated the speech acceptabilities using visual analog scale. 1 segmental (articulation) and 6 suprasegmental features (pitch, loudness, quality, resonance, intonation, and speaking rate) of speech were perceptually evaluated by 3 SLPs. Correlation and multiple regression analysis were performed to evaluate the predicting variables. Results: The means of speech acceptability for reading and spontaneous speech were 73.47 and 71.96, respectively. Speech acceptability of reading was predicated by the severity of intonation and articulation. Speech acceptability of spontaneous speech was predicated by the severity of intonation and loudness. Discussion and conclusion: Severity of intonation was the most effective variable to predict the speech acceptabilities of both reading and spontaneous speech. A further study would be necessary to generalize the result and to apply this result to intervention in clinical settings.

• Journal of Korean Physical Therapy Science
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• v.5 no.4
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• pp.763-775
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• 1998

Some segment or segments of the body must compensate for the heel, and the higher the heel the greater the compensation. Such compensation was once generally thought to take place in the lumbar region and therefore to increase the lumbar lordosis. The purpose of this study is to analyze changes of lumbar sagittal curvature in barefoot and 6cm 12cm high-heel stance. We selected 19 subjects(11 males, 8 females} without history of lower back pain, significant spinal abnormality. And lateral view X-ray of lumbar region from T12 to S1 was taken of each individual. On each X-ray film, lumbar lordotic angle lumbosacral angle and lumbar segmental angles were measured by Cobb method. We drew the following interpretations from the analysis of measured variables of the lumbar region. 1. In comparison of barefoot 6cm heel 12cm heel stance, lumbar lordotic angle had a tendency to decrease according as the heel height was higher. The change in lumbar lordosis measured in high-heel stance was inconsistent with clinical forkelord of hyperlordosis in wearers of high-heeled. 2. Lumbar lordotic angle from T12 to L5 showed sex difference, and was more lordotic in female(p<0.05). 3. There was no sex difference in lumbosacral angle and lumbar segmental angles(p>0.05). 4. There was a significant correlation between lumbar lordotic angle and lumbosacral angle(r>0.60).

• Journal of Korean Medicine Rehabilitation
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• v.21 no.2
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• pp.239-252
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• 2011

Objectives : To investigate and compare the curvature of the cervical spine for the neck pain patients and asymptomatic participants. Methods : Clinical study was carried out for 64 neck pain patients in Conmaul oriental hospital and 56 asymptomatic volunteers. Cervical spine curvature was measured by 7 types of measuring methods. Results : Curvature angles of the cervical spine were significantly lower in the patients group(p<0.05). In segmental analysis of curvature, segmental curvature of C3-C4 were significantly lower in the patients group. There is no significant relationship among the classifications by the types of cervical spine curvature in the 2 groups. Conclusions : The results suggest that the cervical spines of neck pain patients are straightened and kyphotic and most of cervical curvature decrease are occurred at middle cervical spine.

• Korean Journal of Bronchoesophagology
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• v.4 no.1
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• pp.27-34
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• 1998

Despite improvement in respiratory care, including use of low pressure and high volume cuffed tubes, tracheal stenosis remains a serious complication after a long-term tracheal intubation and tracheostomy. In such patients, tracheal resection and primary anastomosis is still considered ideal therapeutic modality. Between 1989 and 1997, we performed tracheal resections with end-to-end anastomosis on 14 patients with no operative mortality and some morbidity. Tracheal stenosis was caused by tracheostomy in nine patients, by endotracheal intubation in three patients and by thyroid carcinoma in two patients. The length of stenosis was various from 2cm to 4.5cm. All patient underwent segmental tracheal resection and primary anastomosis(14 patients) and additional procedures were cricoid cartilage reconstruction(2 patients), suprahyoid laryngeal release(3patients), carinal release technique(2 patients) and arytenoidectomy(2 patients). We have nine complications: granulona at anastomosis site in four patients, vocal cord palsy in two patients and restenosis, pneumonia, skin necrosis in each of those patients. The granuloma was removed by bronchoscopic forceps(4 patients). Vocal cord palsy was treated by arytenoidectorny(2 patients), restenosis by T-tube insertion, pneumonia by antibiotics and skin necrosis was treated by skin graft. We reviews our expenence of clinical features of tracheal stenosis and surgical treatment by tracheal one-to-end anastomosis with additional procedures to avoid postoperative complications for sucessful results.

• Bulletin of the Korean Chemical Society
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• v.13 no.3
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• pp.296-306
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• 1992

$^{13}C$ spin-lattice relaxation times were measured for n-alkanes of moderate chain length, ranging from n-octane to n-dodecane, under the condition of proton broad-band decoupling within the temperature range of 248-318 K in order to gain some insight into basic features of segmental motions occurring in long chain ploymeric molecules. The NOE data showed that except for methyl carbon-13 dipole-dipole interactions between $^{13}C$ and directly bonded $^1H$ provide the major relaxation pathway, and we have analyzed the observed $T_1data$ on the basis of the internal rotational diffusion theory by Wallach and the conformational jump theory by London and Avitabile. The results show that the internal rotational diffusion constants about C-C bonds in the alkane backbone are all within the range of $10^9\;-10^10\;sec^{-1}$ in magnitude while the mean lifetimes for rotational isomers are all of the order of $10^{-11}\;-10^{-10}$ sec. Analysis by the L-A theory predicts that activation energies for conformational interconversion between gauche and trans form gradually increase as we move from the chain end toward the central C-C bond and they are within the range of 2-4 kcal/mol for all the compounds investigated.