• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.325-333
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• 2020

This study compares the rapidity and subjective convenience of T-AED and SC-AED for health care providers and the general public. Subjects were randomly allocated to T-AED (n=77) and SC-AED (n=79) groups. Each group conducted defibrillation, with subsequent measurement of the rapidity of defibrillation in peri-shock pause, pre-shock pause, hesitation pause, and post-shock pause. Defibrillation and chest compression delay times for both equipment were analyzed by t-test. On conclusion of the experiment, subjects answered a questionnaire on the subjective convenience of defibrillation, as measured for confidence, convenience, and clear decision. Comparisons of subjective convenience analyzed by t-test revealed significantly shortened peri-shock pause (11.22s), pre-shock pause (11.04s), and hesitation pause (2.15s) in the SC-AED group, as compared to the T-AED group (p<0.001). However, no significant differences were observed for post-shock pause values. Comparing subjective convenience, confidence (T-AED: 7.62±1.25VAS vs. SC-AED: 7.80±0.98VAS, p=0.358) was not significant, whereas convenience (T-AED: 7.05±1.36VAS vs. SC-AED: 8.95±0.89VAS, p<0.001) and clear decision (T-AED: 6.58±1.73VAS vs. SC-AED: 9.08±0.98VAS, p=0.001) showed statistically significant differences. Our results indicate that compared to T-AED, SC-AED has significantly shortened pauses. Moreover, it is more convenient for the user, and significantly aids in clear decisions.

• Journal of the Microelectronics and Packaging Society
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• v.18 no.4
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• pp.11-18
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• 2011

The quantitative interfacial adhesion energy of the Cu-Cu direct bonding layers was evaluated in terms of the bonding temperature and Ar+$H_2$ plasma treatment on Cu surface by using a 4-point bending test. The interfacial adhesion energy and bonding quality depend on increased bonding temperature and post-annealing temperature. With increasing bonding temperature from $250^{\circ}C$ to $350^{\circ}C$, the interfacial adhesion energy increase from $1.38{\pm}1.06$ $J/m^2$ to $10.36{\pm}1.01$ $J/m^2$. The Ar+$H_2$ plasma treatment on Cu surface drastically increase the interfacial adhesion energy form $1.38{\pm}1.06$ $J/m^2$ to $6.59{\pm}0.03$ $J/m^2$. The plasma pre-treatment successfully reduces processing temperature of Cu to Cu direct bonding.

• The Journal of Engineering Geology
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• v.24 no.1
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• pp.23-38
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• 2014

The composition of carbonate sands from a sabkha at Ruwais in the UAE differs from that of silica sand, and these sands are crushed easily under low compression pressures. Accordingly, particle crushing of carbonate sand occurs under high pressure, which results in additional settlement and reduces the shear strength. In this study, consolidation and triaxial tests were conducted to analyze the characteristics of carbonate sands following particle crushing. The unusual shear strength graphs of the carbonate sands result from the degree of particle pre-crushing. For the range at p' > p in the p (p')-q diagram, negative (-) excess porewater pressures occur if the axial pressure causes particle crushing that induces exposure of the inner voids. In addition, the q value decreased after particle crushing. In conclusion, the unusual characteristics of the carbonate sands were induced by particle crushing. The triaxial tests revealed that the degree of particle pre-crushing influenced the excess porewater pressure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.303-308
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• 2019

Non-traumatic acute myelopathy caused by cervical disc herniation is rare. To date, no case has been reported to be caused by extrusion cervical disc herniation, unrelated to patient posture during surgery. Here, we report the case of a 65-year-old male patient with cervical myelopathy who underwent subsequent arthroscopic rotator cuff surgery under general anesthesia; non-cervical spine surgery. Ed. Notes: I am unable to understand the insertion of the highlighted phrase. Please delete if not required, or revise the sentence appropriately. Patient showed acute postoperative tetraplegia in spite of optimal anesthetic management. He showed no limitation of neck movement at pre-operative airway evaluation, and had no history of trauma to the cervical spine. During surgery, there had been no overextension or twisting of the neck, including at the time of anesthetic induction by tracheal intubation. However, cervical disc herniation causing spinal canal cord compression was detected in the postoperative magnetic resonance imaging, which probably resulted in tetraplegia of the patient. Motor and sensory functions were recovered after 21 days of conservative treatment, including steroid pulse intravenous therapy without any surgical intervention. In this report, the disease is described after reviewing other reported cases; furthermore, we also discuss the pathophysiology of the disease. Based on our report, we propose that under general anesthesia, clinicians should pay attention to the possibility of pre-existing cervical disease, even in non-cervical spine surgeries of geriatric patients.

• The Journal of Engineering Geology
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• v.31 no.2
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• pp.135-148
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• 2021

Ground subsidence risk ratings obtained from the site investigation during pre-excavation stages could be changed depending on the parameters revealed during construction activities. A method of correcting the pre-excavation ground subsidence risk ratings based on the site conditions observed in the field is suggested in this study. The elevation of groundwater table during the excavation may be different from the predicted value depending on the application of waterproofing methods and construction conditions. The drastic drawdown of groundwater table during the excavation could cause ground subsidence due to soil volume decrease related to consolidation or compression of the ground, whereas the rising of groundwater table caused by the intense rainfall may result in a high potential for ground subsidence due to heaving or boiling of the excavation bottom. Excessive displacements of retaining walls or ground settlements may cause ground subsidence, which also results in a high risk of ground subsidence caused by the destruction of buried pipelines. Reevaluation of ground subsidence risk ratings is suggested considering the fluctuation of groundwater table, condition of groundwater leakage, measured ground displacements, and soil types. Finally, the ground subsidence risk rating system is improved for better evaluation by using 12 factors in 5 categories.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.7
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• pp.1172-1179
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• 2006

Recently, the H.264/AVC, which was standardized jointly by ISO/IEC and ITU-T, has been expanding its applications in various areas. This standard includes many advanced component techniques compared to the existing MPEG techniques. Intra prediction which is to predict the spatial data in an intra frame in one of them. But it has a serious defect that it needs large amount of calculation. To overcome this defect, this paper proposed a method to reduce about 60% of the amount of calculation with only O.02dB of image quality degradation. This method determines the calculation directly without much pre-calc cluation process by referring the left block(s) and upper blocks(s) that were processd already. Comparing to the exi sting methods, its image quality degradation is so small that it is expected to be used in many areas. Especially in the wireless appliances such as DMB phone which has restricted power source, we expect it would be used efficiently.

• Structural Engineering and Mechanics
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• v.14 no.3
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• pp.287-306
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• 2002

The assessment of structural performance of transfer structures under potential seismic actions is presented. Various seismic assessment methodologies are used, with particular emphasis on the accurate modelling of the higher mode effects and the potential development of a soft storey effect in the mega-columns below the transfer plate (TP) level. Those methods include response spectrum analysis (RSA), manual calculation, pushover analysis (POA) and equivalent static load analysis (ESA). The capabilities and limitations of each method are highlighted. The paper aims, firstly, to determine the appropriate seismic assessment methodology for transfer structures using these different approaches, all of which can be undertaken with the resources generally available in a design office. Secondly, the paper highlights and discusses factors influencing the response behaviour of transfer structures, and finally provides a general indication of their seismic vulnerability. The representative Hong Kong building considered in this paper utilises a structural system with coupled shear walls and moment resisting portal-frames, above and below the TP, respectively. By adopting the wind load profile stipulated in the Code of Practice on Wind Effects: Hong Kong-1983, all the structural members are sized and detailed according to the British Standards BS8110 and the current local practices. The seismic displacement demand for the structure, when built on either rock or deep soil sites, was determined in a companion paper. The lateral load-displacement characteristic of the building, determined herein from manual calculation, has indicated that the poor ductility (brittle nature) of the mega-columns, due mainly to the high level of axial pre-compression as found from the analysis, cannot be effectively alleviated solely by increasing the quantity of confinement stirrups. The interstorey drift demands at lower and upper zones caused by seismic actions are found to be substantially higher than those arising from wind loads. The mega-columns supporting the TP and the coupling beams at higher zones are identified to be the most vulnerable components under seismic actions.

• The Journal of the Acoustical Society of Korea
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• v.31 no.7
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• pp.427-434
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• 2012

The overlap-add technique based on waveform similarity (WSOLA) method is known to be an efficient high-quality algorithm for time scaling of speech signal. The computational load of WSOLA is concentrated on the repeated normalized cross-correlation (NCC) calculation to evaluate the similarity between two signal waveforms. To reduce the computational complexity of WSOLA, this paper proposes a fast NCC computation method, in which NCC is obtained through pre-calculated sum tables to eliminate redundancy of repeated NCC calculations in the adjacent regions. While the denominator part of NCC has much redundancy irrespective of the time-scale factor, the numerator part of NCC has less redundancy and the amount of redundancy is dependent on both the time-scale factor and optimal shift value, thereby requiring more sophisticated algorithm for fast computation. The simulation results show that the proposed method reduces about 40%, 47% and 52% of the WSOLA execution time for the time-scale compression, 2 and 3 times time-scale expansions, respectively, while maintaining exactly the same speech quality of the conventional WSOLA.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.1
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• pp.47-52
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• 2018

In this study, a collimator composed of multi-dielectric structures is designed using the phase field design method, a kind of topology optimization methods. It is also purposed to improve the mechanical-structural performance of a collimator by replacing previously used air regions with another dielectric material. Polypropylene and paraffin are selected as the dielectric materials for the design process taking manufacturability into account. The design objective is formulated by integrating the intensity of the electromagnetic field in the pre-determined target area to realize the collimating performance. The model for accurate numerical analysis was derived from the final result obtained from the design process through the simple cut-off method and it shows the improved performance of 105% compared with the free space wave propagation. For the designed model, the possibility of reverse transformation, the mechanical durability evaluation under the compression load, and the electromagnetic performance in the X-band range were also evaluated.

• Journal of Korean Neurosurgical Society
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• v.29 no.8
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• pp.1080-1084
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• 2000

Spinal neurenteric cyst results from the persistence of an abnormal communication between endodermal and ne-uroectodermal layer. Embryologically, neurenteric cyst is derived from endoderm that is fused with the developing notochord during the third week of gestation. It is a rare malformation that lead to spinal cord compression. The patient is 19-year-old male presented with chest pain, paresthesia and progressive weakness in his low extremities(grade II/II). Preoperative MR imaging revealed intradural extramedullary cyst with intracystic hemorrhage in T1 and T2 level that is ventrally located and compressed the spinal cord. Involved vertebral bodies were scalloped and fused. The cystic tumor were totally removed through costotransversectomy approach. Postoperatively, motor weakness of the low extremities were improved to the level of grade IV/V. And chest pain and paresthesia were gradually disappeared. Postoperative MR imaging showed the decompression of the thoracic spinal cord. Histologic examination revealed a ciliated columnar epithelial neurenteric cyst. The pre- and postoperative clinical, radiological features of a case of upper thoracic neurenteric cyst is described with review of literature.