• 한국건축시공학회지
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• 제24권1호
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• pp.109-120
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• 2024

성공적인 방수 시공을 위해서는 건축에 사용되는 방수재료의 재질적 성능뿐만 아니라 시공 품질을 확보하는 것이 매우 중요하다. 건설경기 침체에 따른 장기적인 원가절감 정책으로 인해 대부분의 건설사에서는 명확한 품질관리 기준이 없는 고급 방수 자재보다는 일반 저가의 방수 자재를 사용하고 있으며, 건설에 대한 명확한 교육 없이 건설 활동에만 의미를 두고 건설을 진행하고 있다. 또한, 복합적으로 적용되는 방수공법은 시공공법이 복잡하여 시공 품질이 부족하고 방수 불량으로 누수가 발생하는 상황에 놓여있으며, 성공적인 방수공사를 위해서는 품질관리 방안(설계, 자재, 시공)을 검토하고, 파생되는 문제점을 개선하여 안정적인 방수공사가 이루어질 수 있도록 하는 것이 필요하다. 건축물의 누수방지 효과를 기대하기 위해서는 먼저 설계단계에서 건축물의 각 부분과 환경에 적합한 자재를 선정하여야 하며, 선정된 자재는 한국산업규격(KS)의 모든 항목을 만족하여야 한다. 둘째, 방수시고의 품질을 확보하기 위해서는 작업자의 성실한 시공이 요구된다. 본 논문에서는 자재 선정 후 품질관리 대책으로 "방수 설계 검토", "시공자 교육", "현장실사", "비평(수정/보완)"에관한 현장점검 체크리스트를 제시하여 현장에서 안전 및 고품질의 방수공사확보를 위한 개선방안을 제시하였습니다.

• 지질공학
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• 제31권2호
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• pp.135-148
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• 2021

굴착 전 지반조사 결과를 활용한 지반함몰 위험등급 분류는 시공 과정에서 들어나는 인자들에 따라 평가 결과가 다르게 나타날 수 있다. 본 연구에서는 기존 연구에서 제안된 굴착 전 지반조사 결과를 활용한 지반함몰 위험등급 분류 방법을 현장상황을 고려하여 보정하는 방법을 제시하였다. 굴착 진행 중 지하수위는 차수공법의 적용 여부나 시공 상태에 따라 유출되는 정도가 시공 전 예측결과와 다르게 나타난다. 굴착 중 급격한 지하수위 하강은 압밀이나 압축 등의 체적 감소로 지반함몰을 유발하고 집중 호우 등에 의한 수위 상승은 굴착 저면의 히빙이나 보일링을 발생시켜 지반함몰 위험도를 높인다. 굴착 중 흙막이 벽체의 과도한 변위나 지반침하는 지반함몰의 원인이 될 수 있으며, 매설된 관로의 파손을 야기하여 지반함몰 위험도를 높인다. 본 연구에서는 굴착 중 지하수 변동 및 유출상태, 지반변위, 흙의 종류 등을 고려하여 지반함몰 영향인자를 재평가하는 방법을 제안하였다. 최종적으로 지반함몰 평가의 영향인자를 5개 카테고리의 12개 영향인자로 평가할 수 있도록 개선하였다.

• Journal of Chest Surgery
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• 제26권8호
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• pp.595-603
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• 1993

We analysed 60 consecutive patients who got Senning operation for transposition of the great arteries [TGA] with or without ventricular septal defects [VSD]. There were 41 simple TGA [group I] and 19 TGA with VSD [Group II], the operative mortality was 20 % [in group I 4.9 %, group II 52.6 %]. Among the survivors [n=48], the mean follow-up period was 7 years [range, 1 year to 13.5 years] and the actuarial survival rate at 13 years were 95 % in group I and 42 % in group II. Preoperative high left ventricular pressure and high pulmonary arterial pressure affected the surviving [p<0.01]. There occurred various type of arrhythmia like junctional rhythm, first degree atrioventricular [AV] block, sick sinus syndrome and complete AV block, and we inserted 2 permanent pacemakers for these patients. The incidence of arrhythmia were 28.2 % [11/39] in group I and 55.6 % [5/9] in group II, and the actuarial freedom from arrhythmia at 13 years after operation was 66 % [71 % in group I, 44 % in group II]. Increased aortic cross clamping time had affected the development of arrhythmia [p<0.05] which meant the complexity of the operation. The total incidence of left ventricular outflow tract obstruction [LVOTO] was 31.3 % [15/48], but only 3 patients [6.25 %] showed the significant gradient requiring reoperation. The pulmonary venous pathway obstruction [PVO] were found in 3 patients, all in group I, and among them only one required the reoperation. The estimated freedom from PVO was 89 % at 13 years [87 % in group I, 100 % in group II], but we couldn`t find any significant systemic venous obstruction in our series. There occurred 27.1 % [13/48] mild degree tricuspid valve regurgitation without necessary surgical correction. We experienced 14.6 % [7/48] reoperation rate: 3 residual VSD, 3 LVOTO, 1 PVO, 3 atrial baffle leakage. For this high incidence of complication rate after Senning operation and high mortality in TGA with VSD, We do not use this kind of surgical modality any more and do the Jatene operation for all the TGA patients since several years ago.

• Journal of Korean Neurosurgical Society
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• 제58권1호
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• pp.54-59
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• 2015

Objective : The aim of this prospective study was to evaluate the efficacy of bone cement-augmented percutaneous short segment fixation for treating Kummell's disease accompanied by severe osteoporosis. Methods : From 2009 to 2013, ten patients with single-level Kummell's disease accompanied by severe osteoporosis were enrolled in this study. After postural reduction for 1-2 days, bone cement-augmented percutaneous short segment fixation was performed at one level above, one level below, and at the collapsed vertebra. Clinical results, radiological parameters, and related complications were assessed preoperatively and at 1 month and 12 months after surgery. Results : Prior to surgery, the mean pain score on the visual analogue scale was $8.5{\pm}1.5$. One month after the procedure, this score improved to $2.2{\pm}2.0$ and the improvement was maintained at 12 months after surgery. The mean preoperative vertebral height loss was $48.2{\pm}10.5%$, and the surgical procedure reduced this loss to $22.5{\pm}12.4%$. In spite of some recurrent height loss, significant improvement was achieved at 12 months after surgery compared to preoperative values. The kyphotic angle improved significantly from $22.4{\pm}4.9^{\circ}$ before the procedure to $10.1{\pm}3.8^{\circ}$ after surgery and the improved angle was maintained at 12 months after surgery despite a slight correction loss. No patient sustained adjacent fractures after bone cement-augmented percutaneous short segment fixation during the follow-up period. Asymptomatic cement leakage into the paravertebral area was observed in one patient, but no major complications were seen. Conclusion : Bone cement-augmented percutaneous short segment fixation can be an effective and safe procedure for Kummell's disease.

• 전력전자학회논문지
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• 제21권3호
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• pp.224-230
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• 2016

In this study, a single-power-conversion series-resonant ac-dc converter with high efficiency and high power factor is proposed. The proposed ac-dc converter consists of single-ended primary-inductor converter with an active-clamp circuit and a voltage doubler with series-resonant circuit. The active-clamp circuit clamps the surge voltage and provides zero-voltage switching of the main switch. The series-resonant circuit consists of leakage inductance $L_{lk}$ of the transformer and resonant capacitors $ C_{r1}$ and $ C_{r2}$. This circuit also provides zero-current switching of output diodes $D_1$ and $D_2$. Thus, the switching loss of switches and reverse-recovery loss of output diodes are considerably reduced. The proposed ac-dc converter also achieves high power factor using the proposed control algorithm without the addition of a power factor correction circuit and a dc-link electrolytic capacitor. A detailed theoretical analysis and the experimental results for a 1kW prototype are discussed.

• The Korean Journal of Pain
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• 제19권1호
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• pp.56-62
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• 2006

Background: Balloon kyphoplasty is the new technique that helps to decrease the pain and improve mobility as well as restore the vertebral body height and kyphotic curve in fractured vertebrae. We evaluated the outcome of balloon kyphoplasty in the reduction of vertebral body height, kyphotic curve and clinical improvement in the patients with painful vertebral compression fractures. Methods: From July 2002 to February 2005, 84 levels of vertebral compression fractures in 66 patients were treated with balloon kyphoplasty. The assessment criteria were the changes over time in visual analogue scale (VAS) and mobility score. We evaluated the vertebral body height and kyphotic curve at preoperative 1 day and postoperative 1 day. Results: Procedures were performed in 66 patients with a total of 84 affected vertebral bodies. The anterior wall height was restored in 74 / 84 (88%) levels with a mean increment of 2.9 mm, and the mid-vertebral body height was restored in 79 / 84 (94%) levels with a mean increment of 4.2 mm. Kyphosis correction was achieved in 60 / 84 (71.4%) from 10.1 degrees to 7.5 degrees. Pain intensity reduced by 60% in one day after operation and by 75-85% in later time. Mobility scores of all patients were improved immediately after the procedure. Cement leakage occurred in 3 levels but there was no clinical problem. Conclusions: Kyphoplasty is an efficient and safe treatment of painful vertebral compression fracture in pain relief, mobility improvement, and reduction of deformity.

• Journal of Korean Neurosurgical Society
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• 제42권1호
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• pp.6-10
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• 2007

Objective : The purpose of this study was to determine the effect of bone cement augmentation of pedicular screwing in severe osteoporotic spondylolisthetic patients. Methods : Twenty patients with spondylolisthesis (8 : spondylolytic spondylolisthesis 12 : degenerative spondylolisthesis) who had undergone pedicular screwing and interbody fusion for osteoporotic lumbar spine (T-score on bone mineral density<-3.0) from 2002 to 2005 were reviewed. Mean age was 62.3 years with 3 male and 17 female patients. Average follow-up period was 14 months. Average T-score on bone mineral density (BMD) was -3.62. After decompression of neural elements, about 6cc of polymethylmethacrylate (PMMA) was injected into the each vertebral body through transpedicular route. All patients underwent one level interbody fusion and pedicular screw fixation. Clinical outcome was assessed using Oswestry Disability Index (ODI) on the last clinical follow-up. In addition, a modified MacNab's grading criteria was used to objectively assess patient's outcome postoperatively. Radiographic analysis of sagittal contour was assessed preoperatively, immediately postoperatively, and at final follow-up including fusion rate. Results : Eighteen of 20 patients were graded as excellent or good according to the modified MacNab's criteria. An significant improvement of ODI was achieved in both groups. Mean sagittal angle at the preoperative state, postoperative state and at the last follow-up state was $11.0^{\circ},\;20.1^{\circ}$ and $18.3^{\circ}$, respectively, with mean sagittal angle correction gain $7.3^{\circ}$. Firm fusion was achieved in all patients. There were one compression fracture above the fused segment after 6 months follow-up and one case of seroma. But there were no postoperative complications related to bone cement leakage and pedicular screwings such as screw pullout or screw cut-up. Conclusion : Bone cement augmentation of pedicular screwing can be an effective procedure for osteoporotic lumbar spine in spondylolisthetic patients.

• Journal of Korean Neurosurgical Society
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• 제41권5호
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• pp.291-294
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• 2007

Objective : The purpose of this retrospective clinical study was to describe a treatment for osteoporotic burst fracture in the setting of severe fractures involving fragmentation of the posterior wall and neural compromise with symptoms of cord compression. Methods : Indication for microscopic decompression and open kyphoplasty were intractable pain at the level of a known osteoporotic burst fractures involving neural compression or posterior wall fragmentation. A total of 18 patients [mean age, 74.6 years] with osteoporotic thoracolumbar burst fractures [3 males, 15 females] were included in this study. In all cases, microscopic decompressive laminectomy was followed by open kyphoplasty. Clinical outcome using VAS score and modified MacNab's grade was assessed on last clinical follow up [mean 6.7 months]. Radiological analysis of sagittal alignment was assessed preoperatively, immediately postoperatively, and at final follow up. Results : One level augmentation and 1.8 level microscopic decompression were performed. Mean blood loss was less than 100 ml and there were no major complications. The mean pain score before operation and at final follow up was 7.2 and 1.9, respectively. Fourteen of 18 patients were graded as excellent and good according to the modified MacNab's criteria. Overall, 6.0 degrees of sagittal correction was obtained at final follow-up. Conclusion : The combined thoracolumbar microscopic decompression and open kyphoplasty for severe osteoporotic fractures involving fragmentation of posterior wall and neural compromise provide direct visualization of neural elements, allowing safe cement augmentation of burst fractures. Decompressive surgery is possible and risk of epidural cement leakage is controlled intraoperatively.

• 디지털융복합연구
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• 제12권7호
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• pp.1-10
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• 2014

대한변호사협회는 2014년 2월 변호사윤리장전을 개정하면서 변호사의 개인정보 보호 의무에 관한 규정을 신설하였다. 최근 빈번한 개인정보 유출로 개인정보 보호의 중요성이 어느 때보다도 강하게 인식되고 있는 상황에서, 개인정보 보호의무의 신설은 기존의 변호사의 비밀유지 의무로 보호되지 못하는 의뢰인이외 제3자의 개인정보를 보호하고 비밀의 누설 이외 수집, 기록, 보유, 가공, 편집, 검색, 출력 등의 각종 처리에 관하여 규율할 수 있다는 점에서 적지 않은 의의를 발견할 수 있다. 특히 주민등록번호와 같은 고유 식별정보의 암호화는 변호사가 보관 중인 각종 민감정보 유출로 인한 피해를 방지하기 위한 필수적인 조치라고 볼 수 있고, 정보주체의 접근 보장은 자기 정보에 대한 자기 결정권 등 헌법적 가치가 반영된 것으로서 시대의 요청이라고 할 것이다. 이 글에서는 현재 변호사윤리장전이 개인정보 보호의무의 구체적인 내용을 밝히고 있지 않은 가운데, 변호사의 개인정보 보호의무의 일반적인 내용을 살펴보고, 향후 구체적으로 개인정보의 처리가 문제될 수 있는 몇 가지 경우를 살펴본다. 해당 논의가 변호사의 개인정보 보호에 관한 논의에 작으나마 기여하기를 바란다.

• 전기학회논문지
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• 제62권6호
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• pp.798-802
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• 2013

In a conventional DC power supply used for CO2 laser, the circuit elements such as a rectifier bridge, a current-limiting resistor, a high voltage switch, energy storage capacitors ans a high-voltage isolation transformer using high turn ratio are necessary. Consequently, those supplies are expensive and require a large space. Thus, laser resonator and power supply should be optimally designed. In this paper, we propose a new power supply using high frequency resonance phenomena for CW(Continuous wave) CO2 laser (maximum output of 23W with discharge length of 450mm). It consists of a transformer including leakage inductance, magnetizing inductance and half-bridge converter, a three-stage Cockcroft-Walton and PFC(Power factor correction) circuit. The output ripple voltage can be controlled the minimum of 0.24% under the high frequency switching of 231kHz. Furthermore, the output efficiency was improved to 16.4% and the laser output stability of about 5.6% was obtained in this laser system.