• 한국도로학회논문집
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• 제15권5호
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• pp.123-133
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• 2013

PURPOSES : The present paper is to compare vehicles' $CO_2$ emissions in roundabouts and signalized intersections. METHODS : The present paper uses the SIDRA software with variables of traffic and road conditions. RESULTS : The results of the study are as follows : First, when entering traffic volumes are more than 1600pcph, vehicle's $CO_2$ emissions in roundabouts are lower than those of signalized intersections regardless of the left turn ratio. Second, When entering traffic volumes are more than 2800pcph, vehicles's $CO_2$ emissions in 2-lane approaches are lower than those of 1-lane approaches in signalized intersection. Third, when entering traffic volumes are more than 1600pcph, vehicle's $CO_2$ emissions of CASE B are lowest. (CASE B is the condition with one exclusive left-turn lane and one exclusive straight lane and one shared straight lane with right-turn.) Also, CASE A is the condition that vehicle's $CO_2$ emissions in roundabouts are lower than those of signalized intersections between 1600pcph and 3600pcph. (CASE A is the condition with one exclusive left-turn lane and one shared straight lane with right-turn.) But, when entering traffic volumes are more than 4000pcph, vehicle's $CO_2$ emissions in signalized intersections is lower than those of roundabouts. CONCLUSIONS : It may be concluded that vehicle's $CO_2$ emissions on roundabouts are much lower than those of signalized intersections, especially, when entering traffics volumes are between 1600pcph and 3600pcph in 1-lane or 2-lane approaches.

• 소음진동
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• 제8권2호
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• pp.336-345
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• 1998

The dynamic instability of cylindrical shell with clamped-free boundary condition subjected to constant follower force or $P_0 + P_1cos {\Omega}_t$ type pulsating follower force is analyzed. The motion of shell is modeled using the shell theory considering rotary inertia and shear deformation, and analyzed with finite element method. In case of constant follower force, the changes of eigenvalues dependent on the magnitude of applied load are investigated and the critical loads are obtained. In case pulsating follower force, instability regions of exicitation frequency are obtained by modal transform with right and left modal matrix and by multiple scales method. The effects of thickness ratio and aspect ratio on the instability of shell are studied.

• 치과방사선
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• 제7권1호
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• pp.5-8
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• 1977

The author has observed 906 full mouth roentgenograms in Korean young man who had the impacted and supernumerary teeth. Impacted and supernumerary teeth were analysed upon several items, such as incidences and positions in the dental arch. The result were as follows; 1. The incidences of impacted teeth were 59.05% and the ratio of upper jaw to lower one was 1:3. 2. The frequency of the supernumerary teeth were 5.52% and the ratio of maxilla to mandible was 49:1. 3. No significant differences between right and left side in both jaws, but incidence rate of the supernumerary teeth was 74% in the maxillary central incisor area. 4. The positions of impacted and supernumerary teeth were vertical and inverted shapes in maxilla, whereas horizontal and mesio-angular forms in mandible.

• 대한핵의학회지
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• 제31권3호
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• pp.365-371
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• 1997

The aim of this study is to evaluate the efficiency of the pulmonary perfusion scan(Pp scan) in the experimental animal single lung transplantation. Eight left lung transplanted mongrel dogs were included in this study. The serial Pp scan with 111MBq $^{99m}TC-MAA$ were done at the periods of immediate postoperative period, POD 3 days, and POD 10-14 days and finally autopsy was done in each cases. The transplanted lung perfusion was analysed as a percentage radioactivity of trans planted/native lung(T/N) ratio. The Pp scan of a donor mongrel dog was used as a reference(left/right lung (T/N) ratio 85.2%). The average T/N ratio of all cases on immediate postoperative state(reperfusion injury) : 19.2%, three acute rejections. 12.6%, three bronchial dehiscences 6.1% and two pulmonary thromboses : 2.0%. Two cases showed moderate improvement of reperfusion injury as increasing the T/N ratio in POD 3 days Pp scan. The T/N ratio showed sequentially decreased in six cases. As a conclusion, the Pp scan could be a non-invasive method in the evaluation of the experimental one-lung transplanted mongrel dog.

• Geomechanics and Engineering
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• 제32권2호
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• pp.193-207
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• 2023

In general, the numerous classical approaches available in the literature can anticipate the settlement of shallow foundations. As long as the footings are not in close proximity to other subsurface buildings, the findings achieved using these methods are legitimate and acceptable. However, due to increased urbanisation and land scarcity, footings are frequently built close together. As a result, these footings' settlement behaviour differs from those of isolated footings. A simpler approach for assessing the settlement behaviour of two square or rectangular footings placed in close proximity is presented in this work. A Parametric study has been carried out to examine the interference effect on the settlement of these footings placed in close vicinity on the surface of a homogeneous, isotropic and elastic soil medium. The interaction factors are examined by varying the different aspect ratios (L/B), clear spacing ratio (S/B) and intensity of loading on the right footing with respect to the left footing. Further, variation of the settlement ratio (δ/B) with respect to embedment depth ratio D_f/B is examined. For square and rectangular footings, the interference settlement profile is also investigated by varying the clear spacing ratio (S/B) and the degree of loading. The results were compared to 3D finite element analysis and experimental data that were available.

• Tuberculosis and Respiratory Diseases
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• 제38권4호
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• pp.340-346
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• 1991

Tuberculous tracheobronchitis is defined as a specific inflammation of the trachea or major bronchi caused by the tubercle bacillus and recognized as one of the most common and serious complication of pulmonary tuberculosis. It had been a diagnostic challenge in prebronchoscopic era and since 1968, fiberoptic bronchoscopy has been accepted as a safe and valuable diagnostic procedure of tuberculous tracheobronchitis. Now, it remains a troublesome therapeutic problem due to its sequelae such as bronchostenosis, bronchiectasis and bronchial deformity. The authors analyzed the clinical features, radiological findings and bronchoscopic findings with pathologic and bacteriologic study on 61 cases of tuberculous tracheobronchitis and following results were obtained. 1) The peak incidence was in the fourth decade and male to female ratio was 1:3.4. 2) The most common symptom was cough (86.9%) and followed by sputum (49.2%), dyspnea (27.9%), fever (19.8%), weight loss (11.5%), hemoptysis (6.6%), hoarseness (6.6%) and chest discomfort (3.3%) and localized wheezing was heard in 18%. 3) In chest X-ray, consolidation with collapse was observed in 70.5%, and followed by consolidation only (18.0%), mediastinal node enlargement (8.2%), cavitary lesion (6.6%), suspicious hilar mass (3.3%) and miliary lesion (1.6%) and there was no abnormal findings in 4.9%. 4) Bronchoscopy showed hyperplastic lesion in 67.2%, mucosal lesion (18.0%), ulcerative lesion (9.8%) and stenotic lesion (4.9%). The most common site of bronchial lesion was right upper bronchus (36.1%) and followed by right main bronchus (34.4%), left main bronchus (29.5%), left upper bronchus (16.4%), right middle bronchus (8.2%), right lower bronchus (6.6%) and left lower bronchus (3.3%). 5) Chronic granulomatous inflammation with or without caseation necrosis on microscopic examination was confirmed in 69.7%, bronchial washing AFB stain was positive in 34.1%, prebronchoscopic sputum AFB stain was positive in 88.1% and postbronchoscopic sputum AFB stain was positive in 30.1%.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.367-369
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• 2002

We have designed ramp profile excitation pulse based on the Shinnar-Le Roux (SLR) algorithm. The algorithm provides many advantages to pulse designers. The first advantage is the freedom of deciding the amplitudes, frequencies, and ripple sizes of stopband, passband, and transition band of pulse profile. The second advantage is the freedom of deciding the pulse phase, more specifically, minimum phase, linear phase, maximum phase, and any phase between them. The minimum phase pulse is the best choice in the case of 3D TOF, because it minimizes the echo time, which implies the best image quality in the same MR examination condition. In addition, the half echo technique is slightly modified in our case. In general, using the half echo technique means that the acquired data size is half and the rest part can be filled with complex conjugate of acquired data. But in our case, the echo center is just shifted to left, which implies the reduction of echo time, and the acquired data size is the same as the one without using the half echo technique. In this case, the increase of right part of data leads to improvement of the resolution and the decrease of left part of data leads to decrease of signal to noise ratio. Since in the case of 3D TOF, the signal to noise ratio is sufficiently high and the resolution is more important than signal to noise ratio, the proposed method appears to be significantly affective and gives rise to the improved high resolution angiograms.

• 한국방사선학회논문지
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• 제13권2호
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• pp.217-225
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• 2019

본 연구의 목적은 CT와 3.0T MRI 기기를 이용하여 간문맥을 묘출하는데 있어서 신호대 잡음비와 대조 도대 잡음비의 정량적인 수치를 비교 분석 하여 최적의 영상장치를 알아보고자 하였다. 2018년 2월부터 2018년 4월까지 C대학교병원에서 CT와 3.0T MRI 간 검사를 시행한 20명의 환자를 대상으로 의료영상저장전송시스템로 전송된 데이터를 무작위로 선정하였다. 정량적 평가를 위하여 간문맥의 4부위(주문맥, 우문맥, 좌문맥, 중간문맥)의 동일한 관심영역을 선정 후 신호평균값과 표준편차를 측정하여 SNR과 CNR값을 평가하였다. 평가결과 SNR은 CT에서 우문맥 : $9.18{\pm}0.72$, 좌문맥 : $9.41{\pm}0.84$, 중간문맥 : $9.54{\pm}0.59$, 주문맥 : $9.55{\pm}0.75$이고 3.0T MRI에서 우문맥 : $22.29{\pm}2.03$, 좌문맥 : $25.89{\pm}3.19$, 중간문맥 : $24.39{\pm}2.87$, 주문맥 : $26.64{\pm}2.30$으로 측정되었다(p<0.05). CNR은 CT에서 우문맥 : $3.75{\pm}0.66$, 좌문맥 : $3.44{\pm}0.65$, 중간문맥 : $3.71{\pm}0.39$, 주문맥 : $3.79{\pm}0.68$이고 3.0T MRI에서 우문맥 : $9.49{\pm}0.65$, 좌문맥 : $11.00{\pm}01.90$, 중간문맥 : $12.70{\pm}1.75$, 주문맥 : $10.01{\pm}0.98$으로 3.0T MRI가 CT보다 높은 수치로 측정되었다(p<0.05). 결론적으로 4부위의 간문맥을 분석한 결과 SNR과 CNR값이 3.0T MRI에서 높은 것으로 나타났다. 따라서 CT와 3.0T MRI에서 간문맥을 묘출하기 위한 최적의 영상장비는 비전리 방사선을 이용하는 3.0T MRI가 우위로 나타났다.

• Clinical and Experimental Pediatrics
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• 제53권2호
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• pp.190-194
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• 2010

목 적 : 애성 및 음성 변동은 심장병 환자에서 관찰될 수 있는데 이러한 음성 변동 정도를 음향학적 지표의 평가로 분석하여, 소아에서 선천성 심장병 종류에 따른 음성 변동을 음향학적 요소로 분석하고자 하였다. 방 법 : 수술 전 선천성 심장병 환아 94명을 연구 대상으로 하였고 심실 중격 결손, 동맥관 개존, 심방 중격 결손, 폐동맥 협착, 활로 사징이 포함되었으며, 음성 변동을 조사하기 위한 음향 지표 분석은 통증 자극을 통하여 얻어진 음성 자료를 multi-dimensional voice program system을 이용하여 평가하였다. 연구에 사용된 음향 지표로 average fundamental frequency, length of analyzed sample, jitter percent, shimmer, noise to harmonic ratio를 분석하였다. 결 과 : 음향 지표인 average fundamental frequency은 동맥관 개존, 심실 중격 결손, 활로 사징 경우에서 유의한 감소를 나타냈으며, length of analyzed sample은 연구 대상 선천성 심장병 환아에서 대조군에 비해 의미있는 차이를 나타내지 않았다. Jitter percent, shimmer, noise to harmonic ratio는 심실 중격 결손, 동맥관 개존, 심방 중격 결손에서 대조군에 비해 증가되었다. 이러한 음성 변동은 연구 대상 선천성 심장병 중 동맥관 개존에서 음도변이, 강도변이, 음성의 소음 정도가 가장 뚜렷하게 나타났으며, 동맥관 개존, 심실 중격 결손, 심방 중격 결손 순으로 그 음성 변동의 특징을 나타냈다. 결 론 : 수술 전 선천성 심장병 환아에서 음성을 음향학적 지표로 비교 분석한 결과 음향학적 지표들이 심장 질환의 유형별 차이를 보이는데 좌우 단락 심질환군에서 현저한 비정상적 음향학적 지표를 나타냈다.

• 대한토목학회논문집
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• 제36권1호
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• pp.97-104
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• 2016

우리나라의 인구 10만명당 차대사람 사망자 수는 OECD평균보다 약 3배 높고, 특히 생활도로에서 60% 이상 발생하고 있다. 따라서 본 연구에서는 보행자 및 차량의 통행실태 조사를 통해 사고원인을 분석하여 생활도로의 실질적인 안전성 증진방안을 도출하고자 하였다. 최근 보행환경은 우측보행 비율이 증가하고, 보행 중 스마트폰 사용자가 증가하는 등 많은 변화가 일어나고 있다. 통행실태 조사결과, 우측보행이 65%로 높고, 보행중 스마트폰 사용율도 17%로 나타났다. Eye Camera 실험을 통한 운전자의 운전부하량은 생활도로가 도시부 도로에 비해 4배 이상 높게 나타났으며, 속도조사 결과 30km/h이상 주행하는 차량이 62%로 높게 나타났다. 생활도로의 사고특성은 가장자리 통행사고 비율이 전체도로 대비 2.3배 높으며, 우측보행 시 사고가 좌측보행 시에 비해 2.5배 더 많고 우측에서 좌측으로 횡단할 때 더 위험한 것으로 분석되었다. 사고원인은 대부분 안전운전불이행(84.4%)이고, 차량이 좌회전할 때 사고가 우회전대비 2.3배 높고 후진사고의 비율이 14%로 높게 나타났다. 생활도로에서는 운전자가 일반도로에 비해 4배 이상 많은 운전집중력을 가져야하기 때문에 차량을 등지고 보행하거나 부주의한 행동을 하는 것은 사고로 이어질 개연성이 큰 것으로 분석되었다.