• Journal of Korean Neurosurgical Society
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• 제59권3호
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• pp.276-281
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• 2016

Objective : Although trunk muscles in the lumbar spine preserve spinal stability and motility, little is known about the relationship between trunk muscles and spinal fusion rate. The aim of the present study is to evaluate the correlation between trunk muscles cross sectional area (MCSA) and fusion rate after posterior lumbar interbody fusion (PLIF) using stand-alone cages. Methods : A total of 89 adult patients with degenerative lumbar disease who were performed PLIF using stand-alone cages at L4-5 were included in this study. The cross-sectional area of the psoas major (PS), erector spinae (ES), and multifidus (MF) muscles were quantitatively evaluated by preoperative lumbar magnetic resonance imaging at the L3-4, L4-5, and L5-S1 segments, and bone union was evaluated by dynamic lumbar X-rays. Results : Of the 89 patients, 68 had bone union and 21 did not. The MCSAs at all segments in both groups were significantly different (p<0.05) for the PS muscle, those at L3-4 and L4-5 segments between groups were significantly different (p=0.048, 0.021) for the ES and MF muscles. In the multivariate analysis, differences in the PS MCSA at the L4-5 and L5-S1 segments remained significant (p=0.048, 0.043 and odds ratio=1.098, 1.169). In comparison analysis between male and female patients, most MCSAs of male patients were larger than female's. Fusion rates of male patients (80.7%) were higher than female's (68.8%), too. Conclusion : For PLIF surgery, PS muscle function appears to be an important factor for bone union and preventing back muscle injury is essential for better fusion rate.

• 대한방사선기술학회지:방사선기술과학
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• 제46권5호
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• pp.427-433
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• 2023

This study aimed to quantitatively compare the diameters measured directly from the coronal plane or sagittal plane of 2D digital subtraction angiography (DSA) and the cross-sectional area-converted diameters calculated from contrast-enhanced MR (CE-MR) imaging. A retrospective analysis was conducted on 20 patients who underwent both 2D DSA and CE-MR imaging. Firstly, the venous diameters of the superior sagittal sinus (SSS) and transverse sinus (TS) were directly measured from 2D DSA. Subsequently, the axial planes for SSS diameter and the sagittal plane for TS in CE-MR imaging were utilized to calculate cross-sectional area-based converted diameters. The numerical values obtained from 2D DSA and CE-MR imaging were compared pairwise at each location. For SSS, the diameter measured by 2D DSA was 27% larger than the conversion-based diameter from CE-MR imaging (9.8±1.4 mm vs. 7.1±1.3 mm, P<0.05). Similarly, for the right TS, the difference was 16% (8.8±3.2 mm vs. 7.4±2.0 mm, P<0.05), and for the left TS, the difference was 22% (8.4±2.8 mm vs. 6.6±1.3 mm, P<0.05). In conclusion, the diameter measured directly in conventional 2D DSA may be larger than the diameter converted based on the cross-sectional area. Therefore, when selecting the size of the stent, it is crucial to make precise determinations while keeping this fact in mind.

• Restorative Dentistry and Endodontics
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• 제49권2호
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• pp.18.1-18.13
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• 2024

Objectives: This study was conducted to evaluate the mechanical properties of relined and non-relined fiberglass posts when cemented to root canal dentin using a conventional dual-cure resin cement or a self-adhesive resin cement. Materials and Methods: Two types of resin cements were utilized: conventional and self-adhesive. Additionally, 2 cementation protocols were employed, involving relined and non-relined fiberglass posts. In total, 72 bovine incisors were cemented and subjected to push-out bond strength testing (n = 10) followed by failure mode analysis. The cross-sectional microhardness (n = 5) was assessed along the root canal, and interface analyses (n = 3) were conducted using scanning electron microscopy (SEM). Data from the push-out bond strength and cross-sectional microhardness tests were analyzed via 3-way analysis of variance and the Bonferroni post-hoc test (α= 0.05). Results: For non-relined fiberglass posts, conventional resin cement exhibited higher pushout bond strength than self-adhesive cement. Relined fiberglass posts yielded comparable results between the resin cements. Type II failure was the most common failure mode for both resin cements, regardless of cementation protocol. The use of relined fiberglass posts improved the cross-sectional microhardness values for both cements. SEM images revealed voids and bubbles in the incisors with non-relined fiberglass posts. Conclusions: Mechanical properties were impacted by the cementation protocol. Relined fiberglass posts presented the highest push-out bond strength and cross-sectional microhardness values, regardless of the resin cement used (conventional dual-cure or self-adhesive). Conversely, for non-relined fiberglass posts, the conventional dual-cure resin cement yielded superior results to the self-adhesive resin cement.

• 기술혁신연구
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• 제23권2호
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• pp.33-54
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• 2015

국가차원의 슈퍼컴퓨팅 성능수요 예측은 슈퍼컴퓨터를 활용하는 계산과학분야의 연구자나 연구개발 인프라를 구축 운영하고 있는 전문기관, 과학기술 인프라구축을 주도할 정부기관에 있어서 매우 중요한 정보이다. 본 연구는 그동안 진행되었던 슈퍼컴퓨터 성능관련 예측활동 분석을 통해 과학기술 역량에 영향을 미치는 요인들을 도출하고 이를 슈퍼컴퓨터 기술진보 추세에 적용한 복합 예측모형을 제안하였다. 횡단면분석에서는 슈퍼컴퓨팅 성능에 영향을 미칠 것으로 판단되는 GDP, GERD, 연구원수, SCI논문수를 고려한 다중회귀분석을 수행하였다. 그리고 횡단면분석 결과에 Top500 자료의 성능(Rmax)값을 이용한 시계열분석을 통해 도출된 기간별 기술진보율을 곱하여 슈퍼컴퓨터의 성능을 예측하였다. 제안된 예측모형을 바탕으로 세계 슈퍼컴퓨터 500위의 시계열자료를 이용하여 한국이 2016년에 보유해야 할 슈퍼컴퓨터 성능규모를 예측하였다. 횡단면분석과 기술진보율을 적용하여 2016년 한국의 슈퍼컴퓨팅 성능수요를 예측해본 결과 현재의 추세를 이용할 경우 15~30PF 정도, 목표 국가수준의 추세를 이용할 때 20~40PF 정도의 컴퓨팅 역량이 필요할 것으로 예측되었다. 이 결과는 단순 회귀분석을 적용한 결과인 9.6PF와 횡단면분석을 적용한 결과인 2.5PF와 큰 차이를 나타내었다.

• 제어로봇시스템학회논문지
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• 제12권2호
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• pp.113-118
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• 2006

A new last design approach based on the Limb line FFD (LFFD) and Scale factor FFD (SFFD) is presented in this paper. The proposed last design method utilizes the dynamic trimmed parametric patches for the measured foot 3D data and last 3D data. Furthermore, the proposed last data generation system utilizes cross sectional data extracted obtained from the measured 3D foot data. First, the last design rule of the LFFD is constructed on the FFD lattice based on foot last shape analysis. Secondly, SFFD is constructed on the LFFD new lattice based on scale factor deformation. The scale factor is constructed on the boundary edges of polygonized patch and the cross section last data boundary edge of the polygon object. Suppose the two boundary curves have been preprocessed so that they run in the same direction and they forms the SF(Scale Factor). In addition, the control points of FFD lattice are derived with cross. sectional data interpolation methods from a finite set of 3D foot data.

• Structural Engineering and Mechanics
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• 제37권3호
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• pp.309-320
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• 2011

As a new type of large-span space structure, suspendome is composited of the upper single-layer reticulated shell and the lower cable-strut system. It has better mechanical properties compared to single-layer reticulated shell, and the overall stiffness of suspendome structure increases greatly due to the prestress of cable. Consequently, it can cross a larger span reasonably, economically and grandly with high rigidity, good stability and simple construction. For a better assessment of the advantages of mechanical characteristic of suspendome quantitatively, the static behavior of Kiewitt6 suspendome was studied by using finite element method, and ADINA was the software application to implement the analysis. By studying a certain suspendome, the internal forces, deformation and support constrained forces of the structure were obtained in this paper. Furthermore, the influences of parameters including prestress, stay bar length, cross-sectional area and rise-to-span ratio were also discussed. The results show that the increase of prestress and vertical stay bar length can improve the stiffness of suspendome; Cross-sectional area has nearly no impact on the static behavior, and the rise-to-span ratio is the most sensitive parameter.

• Journal of Chest Surgery
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• 제32권5호
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• pp.442-447
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• 1999

서론: 성장기에서 기관의 성장양상에 관한 이해는 수많은 기관질병의 관리나 선천성 기관협착증에서 기관 성형술 등에서 매우 중요한 지표가 된다. 그러나 이에 관한 국내의 연구례가 거의없는 실정이다. 본 연구는 한국인 소아에서 기관의 내경과 단면적을 후향적으로 분석하여 기관질환의 치료에 기초자료를 제공하고자 한다. 대상 및 방법: 1996년 5월부터 1998년 8월까지 흉부전산화 단층촬영을 시행한 0세부터 20세까지 106명의 환자를 대상으로 하였는데 기관의 내경이나 단면적에 영향을 줄 수 있는 기관질환, 과거에 개흉술을 받은 경우, 종격동 종양, 폐쇄성 폐질환이 있는 경우는 본 연구에서 제외시켰다. 남자가 69명, 여자가 37명이었으며 기관의 종단내경과 횡단내경은 흉부유입부와 대동맥궁 부위에서 각각 측정하였다. 기관의 형태는 각 부위의 단면에서 원형, 타원형, 말발굽형으로 구분하였으며 단면적은 A = 1/4$\pi$ab (A: 단면적, $\pi$: 3.14, a: 종단내경, b: 횡단내경)의 공식으로 계산하여 각 부위의 내경과 연령 및 성별에 따른 단면적을 비교 분석하였다. 통계처리에서 p값이 0.05이하일 때 통계적 의미가 있는 것으로 간주하였다. 결과: 5세이하에서는 level I과 II 모두에서 기관의 형태가 원형을 이루고 있었으며 두 부위간의 단면적의 차이는 없었다. 성장함에 따라 level I의 형태는 타원형으로 변해가는 반면 level II에서는 그대로 원형을 유지하고 있었으며 level I의 단면적이 level II 보다 크다(p=0.020). 기관의 내경과 단면적은 성장함에 따라 직선관계로 증가한다는 것이 확인되었고(r>0.9), 5세이하의 소아에서는 여자가 남자보다 기관의 단면적이 크고 (p=0.020) 15세가 넘으면 반대로 남자가 더 크다 (p=0.002). 결론: 이상의 결과에서 흉부전산화 단층촬영은 기관의 내경과 단면적을 측정하는데 있어 안전하고 확실한 방법이며 성장기의 한국인에서 기관의 내경과 단면적에 대한 지표가 되고자 한다.

• EDISON SW 활용 경진대회 논문집
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• 제4회(2015년)
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• pp.184-190
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• 2015

On wide variety of fields, studies on active twist control are becoming more active. For effective twist control, blades have to have low torsional stresses with high torsional deformations to the same magnitude of torque acting on its cross-section. In this study, 2D sectional analysis and 3D finite element analysis were made for 5 different blades with each having different cross - sections which have different spars. The results from 2D sectional analysis, were then put into 3D blade deformation and stress calculations which lead to analysis. Outcomes from 2D and 3D analysis, showed that on the same torque and concentrated load conditions, the blade with 'C' shaped spar was the best of all the blades which were used in this study.

• 한국철도학회논문집
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• 제14권3호
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• pp.285-294
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• 2011

R&D 투자로 인한 기술의 축적, 경제적 성과 및 파급효과에 대한 분석이 거시적인 측면과 타 부문에서는 다양하게 이루어지고 있으나 철도산업에 대한 분석은 미흡한 실정이다. 본 연구에서 성과목표 설정에 대해서는 선행연구에 대한 조사분석을 통하여 과학기술적 성과에 대한 공통지표로 지식재산권, 특허, 논문을 설정하고 성공적으로 종료된 철도 R&D 11개 사업의 과학기술적 성과에 대한 적정성을 검증하였다. 선행연구에서 투입요소로 투자금액에 의한 성과목표를 설정하였으나 정확도를 향상시키기 위해 투입요소로, 투자금액(RI), 자본적 투자금액(RCI), 인당 내부인건비(LCPM)를 적용하였으며 철도 R&D 11개 사업에 대한 횡단면 분석과 잔차 분석을 통하여 성과목표 모형을 설정하고 타 과제 분석을 통하여 실증분석과 타당성을 검증하였다.

• 전산구조공학
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• 제24권1호
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• pp.43-48
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• 2011