• 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.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제37권2호
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• pp.109-113
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• 2011

Introduction: To correct the facial asymmetry by mandibular jaw surgery, it is important to know the anatomy of the mandible including the mandibular canal positioning of patients with facial asymmetry. This study was performed to evaluate the differences in the cross-sectional surface in the body of the mandible between the deviated side and opposite side in patients with facial asymmetry. Materials and Methods: The study was conducted on 37 adult patients composed of 2 groups, the asymmetry group (n=20) and non-asymmetry group (n=17). Using the cross-sectional computed tomography (CT) images, the distance from the buccal aspect of the mandibular canal to the outer aspect of the buccal cortex, distance from the buccal aspect of the mandibular canal to the inner aspect of the buccal cortex, distance from the inferior aspect of the mandibular canal to the inferior border of the mandible, thickness of the mandible, and cross-sectional surface area of the mandible were measured in each side of the mandible Results: The cross-sectional area of the mandible including the mandibular canal positioning in the deviated side was not statistically different from the opposite side in the asymmetry group. Only the distance from the inferior aspect of the mandibular canal to the inferior border of the mandible in the ramus area of the deviated side was significantly longer than opposite side. On the other hand, the bucco-lingual width of the asymmetry group was thinner than the non-asymmetry group. Conclusion: The cross-sectional area including the mandibular canal of the mandible did not appear to be modified by the facial asymmetry.

• Journal of Korean Biological Nursing Science
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• 제13권2호
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• pp.179-184
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• 2011

Purpose: The purpose of this study was to examine the effect of short-term undernutrition on muscle weight and Type I and II fiber cross-sectional area of hindlimb muscles in undernourished rats. Methods: Adult male Sprague-Dawley rats were randomly assigned to one of two groups: The undernourished (UN) group (n=9) and the control (C) group (n=9). A control group was allowed to have water and pellet ad libitum for 5 days. Undernutrition was induced by providing 32% of total intake of the control group for 5 days. Body weight of two groups and food intake of the control group were measured every day. At 6 days all rats were anesthetized and soleus, plantaris and gastrocnemius muscles, and liver were dissected. Body weight, food intake, muscle weight, liver weight and cross-sectional area were determined. Results: The UN group at 6 days after undernutrition showed significant decreases, as compared to the control group in body weight, liver weight, muscle weight of soleus, plantaris, and gastrocnemius, and Type I fiber cross-sectional area of soleus and gastrocnemius muscles and Type II fiber cross-sectional area of plantaris and gastrocnemius muscles. Conclusion: Hindlimb muscle atrophy occurs from the short-term undernutrition.

• 제어로봇시스템학회논문지
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• 제7권3호
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• pp.246-254
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• 2001

In this paper, we described an approach to the automation of visual inspection of BGA solder joint defects of surface mounted components on printed circuit board by using neural network. Inherently, the BGA solder joints are located underneath its own package body, and this induces a difficulty of taking good image of the solder joints by using conventional imaging systems. To acquire the cross-sectional image of BGA sol-der joint, X-ray cross-sectional imaging method such as laminography and digital tomosynthesis has been cur-rently utilized. However, the cross-sectional image obtained by using laminography or DT methods, has inher-ent blurring effect and artifact. This problem has been a major obstacle to extract suitable features for classifi-cation. To solve this problem, a neural network based classification method is proposed int his paper. The per-formance of the proposed approach is tested on numerous samples of printed circuit boards and compared with that of human inspector. Experimental results reveal that the method provides satisfactory perform-ance and practical usefulness in BGA solder joint inspection.

• 대한기계학회논문집B
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• 제28권7호
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• pp.850-856
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• 2004

When a shock wave arrives at the open end of a tube, an impulsive wave is discharged from the tube exit and causes serious noise and vibration problems. In the current study, the effect of the cross-sectional area of a circular tube on the impulsive wave is investigated using computational methods. Marten-Yee's TVD scheme was employed to solve axisymmetric, unsteady, compressible Euler equations. With a change in the cross-sectional area of the tube, the Mach number of an incident shock wave is varied between 1.01 and 1.50. The results obtained show that the magnitude of the impulsive wave strongly depends upon the Mach number of the incident shock wave and the cross-sectional area of the tube. It is also found that for a given cross-sectional area of the tube, the impulse wave has strong directivity to the tube axis.

• 한국구조물진단유지관리공학회 논문집
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• 제27권5호
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• pp.89-96
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• 2023

본 연구에서는 강봉댐퍼의 변위의존성 평가, 강도 및 에너지소산능력을 평가하였다. 실험 변수는 단면형상 및 형상비이며, 총 6개의 실험체를 제작하였다. 실험 결과, 설계기준에서 제시한 변위 의존성 조건을 모든 실험체가 만족하는 것으로 평가되었다. 그리고 단면형상에 따른 강도 영향은 미비하였다. 결과적으로, 형상비 13.7의 강도 및 에너지소산능력이 우수한 것으로 평가되었다.

• Fibers and Polymers
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• 제4권4호
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• pp.199-203
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• 2003

In order to investigate the effects of cross-sectional shapes on the sound characteristics of polyester fibers, 10 specimens were woven into a twill structure made of round, hollow, triangular, u-shape, cruciform, and composite cross-sectional (▲/▲ ,()/▲, Y/Y) fibers. Their rustling sounds were recorded, and their sound spectra were obtained from FFT analysis. Physical sound parameters (LPT, ΔL, Δf) and Zwicker's psychoacoustic parameters of the loudness(Z), sharpness(Z), roughness(Z), and fluctuation strength(Z) were calculated from the sound spectra. According to noncircular cross-section fibers, the hollow shaped fiber had the highest value of LPT, ΔL, loudness(Z), and fluctuation strength(Z). The triangular shaped fiber had a lower value of LPT, ΔL, loudness(Z), and roughness(Z) than those of the round shaped fiber. Among composite cross-section fibers, C1(▲/▲) and C3 (Y/Y) had higher values of LPT, ΔL, Δf and loudness(Z) but C2(()/▲) had lower values. Also the LPT, ΔL, sharpness(Z), and roughness(Z) values of different denier were similar to each other, but the Δf and loudness(Z) values increased as the denier increased.

• 아태비즈니스연구
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• 제11권4호
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• pp.243-254
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• 2020

Purpose - This paper explores whether overnight returns measured from the last closing price to today's opening price explain the cross-section of stock returns. Design/methodology/approach - This study is conducted using the Korean stock market data from 1998 to 2018, obtained from DataGuide database. The analysis begins with portfolio-level tests, followed by firm-level cross-sectional regressions. Findings - First, when decile portfolios sorted on the daily average of overnight returns in the previous months, the highest decile portfolio exhibits a significant negative risk-adjusted return. This suggests that stocks with higher average overnight returns are temporarily overvalued due to buying pressure from investors. Second, at least 6 months of persistence exists in average overnight returns, which is in line with the results reported by Barber, Odean and Zhu (2009) that investor sentiment persists over several weeks. Finally, Fama-MacBeth cross-sectional regression of expected returns after controlling for a variety of firm characteristic variables such as firm size, book-to-market ratio, market beta, momentum, liquidity, short-term reversal, the slope coefficient for overnight returns remains negative and statistically significant. Research implications or Originality - Overall, the evidence consistently suggests that overnight return is considered as a new priced factor in the cross-section of expected returns. The findings of this paper not only adds to finance literature, but also could be useful to practitioners in making stock investment decision.

• 한국콘텐츠학회논문지
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• 제13권11호
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• pp.288-296
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• 2013

본 연구의 목적은 수근관증후군 뇌졸중 환자에서 경직정도에 따른 정중신경 단면적, 신경전도속도 및 상지기능 차이를 알아보고자 하였다. 연구대상은 성인 뇌졸중 환자 42명에서 CTS군 21명과 Non-CTS군 21명으로 선정하였다. 측정방법으로는 정중신경 단면적, 신경전도속도, GST, FMAS, CTS-FSS로 측정하였다. 연구결과, CTS군과 Non-CTS군 간 각 등급에서 정상측(p<.001)과 마비측(p<.001)의 정중신경 단면적, 정중 운동신경과 감각신경 기시잠시는 통계학적으로 유의한 차이가 있었다. CTS군과 Non-CTS군 간 각 등급에서 GST(p<.05), FMAS(p<.05), CTS-FSS(p<.001)는 통계학적으로 유의한 차이가 있었다. 본 연구는 수근관에 대한 병리역학적 내용을 제시함으로서 뇌졸중 환자의 상지기능훈련 시 고려해야할 내용 중 하나임을 제시하였다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제34권1호
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• pp.34-40
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• 2012

Purpose: The study was performed to compare patients with anatomical variations in facial asymmetry with patients in the normal range using cone-beam computed tomography (CBCT) and to take the preoperative condition into consideration in the case of a sagittal split ramus osteotomy (SSRO). Methods: The study was conducted on 46 adult patients composed of 2 subdivided groups, an asymmetry group (n=26) and a symmetry group (n=20). The asymmetry group was divided between patients with hemimandibular hyperplasia (HH, n=8) and hemimandibular elongation (HE, n=18). Using cross-sectional computed tomography images, the thickness of cancelleous bone in the buccal area of the mandible, thickness of buccal cortex in the buccal aspect of the mandible, thickness of cancellous bone in the inferior aspect of the mandible, thickness of buccal cortex in the inferior aspect of the mandible, and cross-sectional surface area of the mandible were measured. Results: In the asymmetry group, the cross-sectional area of the mandible including the inferior alveolar nerve positioned on the affected side was significantly different from the symmetry group. Thickness of cancelleous bone in the buccal aspect of the mandible, thickness of cancelleous bone in the inferior aspect of the mandible, and cross-sectional surface area of the mandible in the affected site of hemimandibular hyperplasia was significantly smaller than in the symmetry group. Conclusion: The inferior alveolar nerve runs lower and in a more buccal direction and shows a smaller cross-sectional surface of the mandible in the hemimandibular hyperplasia patients with asymmetry.