PURPOSES : This study aims to perform a quantitative analysis of Forward Collision Warning and crash frequency using heavy vehicle driving data collected in expressway driving environments, and to classify the driving environments where Forward Collision Warnings of heavy vehicles occur for accident-prone areas and analyze their occurrence characteristics. METHODS : A bivariate Gaussian mixture model based on inter-vehicle distance gap and speed-acceleration parameters is used to classify the environment in which Forward Collision Warning occurs for heavy vehicles driving on expressways. For this analysis, Probe Vehicle Data of 80 large trucks collected by C-ITS devices of Korea Expressway Corporation from May to June 2022. Combined with accident information from the past five years, a detailed analysis of the classified driving environments is conducted. RESULTS : The results of the clustering analysis categorizes Forward Collision Warning environments into three groups: Group I (highdensity, high-speed), Group II (high-density, low-speed), and Group III (low-density, high-speed). It reveals a positive correlation between Forward Collision Warning frequency and accident rates at these points, with Group I prevailing. Road characteristics at sites with different accident incidences showed that on-ramps and toll gates had high occurrences of both accidents and warnings. Furthermore, acceleration deviation at high-accident sites was significant across all groups, with variable speed deviations noted for each warning group. CONCLUSIONS : The Forward Collision Warning of heavy vehicles on expressways is classified into three types depending on the driving environment, and the results of these environmental classifications can be used as a basis for building a road environment that reduces the risk of crashes for heavy vehicles.

PURPOSE: 본 연구의 목적은 둥근어깨자세(round shoulder posture)와 전방머리자세 (forward head posture)에 따라 폐활량 측정과 산소포화도 및 횡격막 움직임 크기의 상관관계를 알아보는 것이다. METHODS: 연구의 대상은 만성 심장질환 및 호흡기 질환을 가지고 있거나, 정신적, 인지적 장애가 있는 자, 척추옆굽음증(scoliosis)이 있는 자, 목과 갈비뼈 손상이나 수술 병력이 없는 50명의 자원한 사람으로 선정되었습니다. 통계분석은 피어슨(Pearson)의 상관분석을 실시한다. RESULTS:둥근어깨자세는 FVC,FEV1,FEV1/FVC%,PEF 에 대해 양의 상관계수를 보이고 이중 PEF가 가장 상관성이 높았다(p<.05). 횡격막 움직임의 크기(DMD)에 대해서도 양의 상관계수를 보였다. 그러나 TAD(table acromion distance)와는 음의 상관관계를, SPO2는 PM/C7~acro, TAD(table acromion distance) 둘다 음의 상관관계가 나타났다(P>.05). 전방머리자세는 CVA와 CRA 모두 FVC,FEV1,FEV1/FVC, PEF 비율에 대해 유의한 상관관계가 없다(p>.05). CRA와 DMD에는 유의한 차이가 있는 음의 상관관계가 나타났지만(p<.05), CVA와 DMD에는 유의한 상관관계가 발견되지 않았다. 또한 CVA와 CRA 모두 SPO2에 대해 유의한 상관관계가 없다(p>.05). CONLUSION: 결론적으로 전방머리자세의 각도와 둥근어깨 자세에 따라 폐활량과 횡격막 움직임에 영향을 미친다는 것을 확인 할 수 있었다. 하지만 좀더 많은 인원과 대상자들의 경직된 자세에 대해 제한할 방법을 추가적으로 찾을 필요가 있다.

Recently, due to the rapid increase in vehicle accidents, research on improving seat belts and restraint system are being actively on going to solve the problems in vehicle for passengers. The characteristics of lap belt load and pelvic displacement were simulated through MADYMO program using Hybrid III 50th percentile male dummy to analyze the submarining by changing the collision speed and seat back angle by applying the forward collision pulse form accident scenario. As a result, the submarining occurred when the seat-back angle was 60° or higher at the collision speed of 50km/h or higher. Lastly, using the characteristics of the lap belt load and pelvic displacement when the anti-submarining belt (ANSB) system adapted, the pelvic displacement was reduced as well as submarining.

목적 : 한국 성인에서 성별과 연령에 따른 전안부 계측치(전방깊이와 전방각)를 평가하고자 하였다. 방법 : 평균 연령 35.38±15.75(20∼68)세의 92명 160안을 대상으로 하였다. 회전 샤임플러그 카메라(Pentacam, Oculus, Wetzlar, German)를 이용하여 안구 전안부를 측정하였다. 촬영된 샤임플러그 이미지에서 전방깊이와 전 방각의 평균값과 네 지점(상측, 하측, 코측, 그리고 귀측)에서의 방향별 측정값을 평가하였다. 결과 : 전체 대상자의 전방깊이는 평균 2.97±0.39 mm로 연령이 증가할수록 전방깊이가 얕아졌다. 코측(1.87± 0.39 mm)과 상측(1.85±0.39 mm)은 귀측(2.29±0.40 mm)과 하측(2.20±0.41 mm)보다 통계적으로 유의하게 얕 은 전방깊이를 보였으며, 4방향에서 모두 20대에서 60대로 갈수록 점차 전방깊이가 얕아졌다. 전방각은 평균 36.44± 6.76°로 연령이 증가할수록 전방각이 좁아졌다. 상측(34.23±7.52°)과 하측(33.27±6.76°)은 코측(38.28±7.28°) 과 귀측(39.98±7.13°)보다 통계적으로 유의하게 좁은 전방각을 보였으며, 4방향에서 모두 20대에서 60대로 갈수 록 점차 전방각이 좁아졌다. 결론 : 연령이 증가함에 따라 전방깊이는 얕아지고 전방각은 좁아졌으며, 연령증가에 따른 방향별 감소의 경향 이 다르게 나타났다.

층류 경계층 내 반구에 의해 유기되는 말굽와류를 흡입 제어했을 때 후류영역에서의 마찰저항 변화를 측정하였다. 이를 위해 회류수조에서 유동가시화를 실시하여 최적의 자유유속, 반구 크기 및 흡입제어 구멍 크기를 결정하였고, 반구 후류영역에 설치된 평판과 연결된 동력계로 표면 마찰저항 감소를 측정하는 실험을 수행하였다. 평판에 설치된 반구 전방에는 유입 유동에 의해 반구를 감싸는 말굽와류가 생성되며 그 주위 와도 방향에 의해 후류영역으로는 빠른 유속의 유동이 유입되어 머리핀 와류 생성을 촉진시킨다. 따라서 반구 전방에 생성되는 말굽와류 세기를 흡입 제어에 의해 약화시킴으로써 반구 좌우측으로 길게 형성된 유속방향 와류가 후류영역으로 공급하는 에너지는 감소하게 된다. 즉, 반구 전방의 말굽와류를 제어함으로써 후류영역으로부터 생성되는 헤어핀 와류 발생 주파수가 줄어 들게 된다. 염료 주입을 이용한 유동 가시화 영상을 해석한 결과로 머리핀 와류의 발생 빈도가 흡입제어에 의해 36.4 % 감소되었고, 후류 영역에서 측정된 표면 마찰저항은 2.3 % 감소되는 것으로 나타났다.

Background: Limitations in hip flexion caused by tight hamstrings lead to excessive lumbar flexion and low back pain. Accordingly, many studies have examined how to stretch the hamstring muscle. However, no study has focused on the effect of hamstring eccentric exercise for tight hamstrings on trunk forward bending. Objects: We compared the short-term effect of hamstring eccentric exercise (HEE) and hamstring static stretching (HSS) on trunk forward bending in individuals with tight hamstrings. Methods: Thirty individuals with tight hamstrings participated in the study. The subjects were randomly allocated to either a HEE or HSS group. To determine whether the hamstrings were tight, the active knee extension (AKE) test was performed, and the degree of hip flexion was measured. To assess trunk forward bending, subjects performed the fingertip to floor (FTF) and modified modified Schober tests, and the degree of trunk forward bending was measured using an inclinometer. We used paired t-tests to compare the values before and after exercise in each group and independent t-tests to compare the two groups on various measures Results: The FTF test results were improved significantly after the exercise in both groups, and AKE for both legs increased significantly in both groups. There was no significant difference in the hip angles, mmS test results, or degree of trunk forward bending between groups after the exercise. No test results differed significantly between the two groups at baseline or after the exercise. Both groups increased hamstring flexibility and trunk forward bending. Conclusion: HSS and the HEE groups increased hamstring flexibility and trunk forward bending. However, HEE has additional benefits, such as injury prevention and muscle strengthening.

난류경계층이 유지되기 위한 에너지 공급은 경계층 내 구조물인 와류들의 상호작용으로 끊임없이 이루어진다. 이러한 난류 유동은 수송분야의 마찰저항 및 해양구조물의 침식 및 진동을 유발하기 때문에 유동 제어를 위한 연구가 활발히 진행되고 있다. 이러한 제어의 극대화를 위해서는 난류 에너지 전달이 어떻게 이루어지는지에 대한 메카니즘 규명이 필수적이고, 이를 위해서는 층류경계층 내 유동현상으로 파악하는 것이 명확하고 용이하다는 장점이 있다. 따라서, 본 연구에서는 층류경계층 내 평판에 반구를 설치하여 역압력구배을 발생시킴으로써 교란된 유동현상의 상호작용을 분석하였다. 즉, 반구를 둘러싼 목걸이 와류와 반구 표면의 유동 박리에 의한 후류영역에서 머리핀 와류가 생성되어 상호 유기적으로 영향을 주고받는다. 이 과정에서 목걸이 와류는 후류영역으로 높은 운동량의 유체를 유입시켜 머리핀 와류의 발생 주파수를 증가시킨다. 반구 전방에 구멍을 뚫어 국부적인 흡입제어로 목걸이 와류의 와도를 감소시킴으로써 그 영향이 완화되는 과정을 유동 가시화 및 열선유속계로 측정하여 정성 및 정량적으로 분석하였다.

목적: 라섹수술 후 잠재적인 각막의 형상 변화 여부를 확인하기 위해서 Pentacam을 이용 하여 수술 후의 각막 및 전방의 변화를 관찰하였다. 방법: 라섹수술을 시행한 38명(76안)을 대상으로 수술 전과 수술 6개월 후에 Pentacam Oculus, Germany)을 이용하여 각막 전면과, 후면의 비구면도, 각막높이, 중심각막두께, 전방 깊이, 전방 부피를 측정하였다. 통계분석은 SPSS version 18.0을 사용하여 각막 전면과 후면의 비구면도(Q-value), 중심 상승(Central elevation), 중심각막두께, 전방깊이, 전방각, 전방부피를 Paired t-test를 사용하여 비교하였다. p<0.05를 통계적으로 유의한 결과로 보았다. 결과: 라섹수술에 의해 각막 전면의 비구면도는 수술 전 –0.2236 ± 0.1012 ㎛ 에서 수술 후 0.872 ± 0.467 ㎛ 으로 변하여 prolate 형태가 oblate 형태로 변했고, 중심 상승은 수술 전 2.14 ± 1.73 ㎛에서 수술 후 –31.75 ± 14.41 ㎛로 감소했으며, 중심각막두께는 수 술 전 556 ± 31.32 ㎛에서 수술 후 462 ± 40.14 ㎛로 감소하였다. 각막 후면은 수술 후 변화가 없었지만 전방 깊이, 전방각 및 전방부피는 각각 0.085 mm , 0.973° , 7.216 ㎣ 만큼 유의하게 감소하였다(p=0.000). 결론: Pentacam을 이용하여 라섹수술 전과 후 각막 후면은 변화를 보이지 않았지만 전방 깊이, 전방각 및 전방 부피가 감소하는 변화를 보여 장기간 추적 관찰이 필요할 것으로 생각된다.

With increasing demands of transportation services for disabled or aged people, who need wheelchairs, it is recommended to install wheelchairs inside automotive vehicles. However, wheelchairs are not effectively safe devices during car crash unless they are properly fixed. So far, few data have been found related to wheelchair safety or characteristics during car crash, therefore, frontal crash simulations have been carried out based on the FE models of a dummy and a conventional wheelchair including the wheelchair fixing belts and the install plate in the present study. Head injury criteria (HIC) and motion criteria (MC) are investigated and the optimum value of the design variable was found by the Robust design.

Odontomas are mixed odontogenic tumors in which both the epithelial and mesenchymal components have undergone functional differentiation. Two types of odonotma are histomorphologically recognized: complex and compound. Complex odontomas have little or no morphologic similarity to normal tooth formation, and they commonly found in the posterior mandible. They are typically asymptomatic, and the most common presenting symptom is usually lack of eruption of a permanent tooth. The recommended treatment for an odontoma is conservative surgical excision. No tendency for recurrence has been noted. An eight-year-old girl was presented with swollen mouth floor. Radiographically, there were radiopaque mass on anterior mandible with impacted lower left central incisor. Under midazolam intraoral sedation and N2O-O2 inhalation sedation, the odontomas were surgically removed. The diagnosis was complex odontoma. After follow-up of 28 months period, there was no recurrence. The impacted tooth erupted spontaneously and the space for the erupted tooth was regained orthodontically.

This study investigated the effect of a load of 15% body weight on trunk, pelvis and hip joint coordination and angle variability in subjects with and without chronic low back pain (CLBP) during an anterior load carriage task. Thirty volunteers participated in the study (15 without CLBP, 15 with CLBP). All participants were asked to perform an anterior carriage task with a load of 15% body weight. The outcome measures included the means and standard deviations for measurements of three-dimensional coordination and angle variability of the trunk, pelvis and hip joint. As CLBP patient group .06, control group .70, the correlation coefficient between the groups showed a significant difference only in trunk-pelvic in the sagittal plane (p<.05). Angle variability of CLBP patient group increased significantly in the trunk in frontal plane, the pelvis in all sagittal plane, frontal plane, transverse plane, and the hip in sagittal plane, the hip in frontal plane than angle variability of control group (p<.05). This results mean that the CLBP patient group showed a disconnected coordination pattern in the trunk-pelvis in the sagittal plane, an increased pelvic angle variability in all three planes, and hip angle variability in the sagittal, and frontal planes. The CLBP patient group may have developed a compensatory movement of the pelvis and hip joint arising from the changed stability due to the abnormal coordination patterns of the trunk-pelvic in the sagittal plane. Therefore, CLBP symptoms can potentially worsen in the pelvis and adjacent hip joint in CLBP patients who perform weight-related behaviors in their daily lives. Further research is needed to determine the three-dimensional characteristics of the electromyography and neuromuscular aspects of subjects with CLBP.

목적:전방에서 군 생활을 했던 예비역들이 겪었던 고통의 구조를 알아보고자 하였다.연구방법:전방에서 군 생활을 했던 경험이 있던 예비역 10명과 2013년 3월부터 5월까지 두 달간 1~2회 대화를 실시하였다. 참여자들이 전방에서 경험했던 고통체험에 대하여 반복되는 이야기나 더 이상 새로운 내용이 나오지 않는 포화상태까지 자료를 수집하였다. 자료수집 및 분석은 Parse의 인간되어감 이론의 절차에 따라 이루어졌다.결과:연구결과 전방에서 군 생활을 하며 겪었던 고통은 혹독한 추위 속에서의 생활, 자유가 박탈된 감옥 같은 생활, 북한이 언제든 공격할 것이라는 생각 등으로 나타났다. 이 고통체험들은 시간이 지나고 사회생활을 하면서 자신의 인생에 밑거름이 되었고 기분 좋은 추억으로 남았다. 결론:군대에 정신보건 작업치료사들이 전문인력으로 배치되면 군인들의 심리적, 정신보건적인 부분에 긍정적인 영향을 미쳐 군 생활에 잘 적응하고 느끼는 고통을 줄이며, 나아가 자살을 예방할 수 있을 것이다.

PURPOSES : This study aimed to analyze the impact the operation of pre-signals at 4-leg signalized intersections and present primary environmental factors of roads that need to be considered in the installation of pre-signals. METHODS : Shift of proportions safety effectiveness evaluation method which assesses shifts in proportions of target collision types to determine safety effectiveness was applied to analyze traffic crash by types. Also, Empirical Bayes before/after safety effectiveness evaluation method was adapted to analyze the impact pre-signal installation. Negative binomial regression was conducted to determine SPF(safety performance function). RESULTS : Pre-signals are effective in reducing the number of head on, right angle and sideswipe collisions and both the total number of personal injury crashes and severe crashes. Also, it is deemed that each factor used as an independent variable for the SPF model has strong correlation with the total number of personal injury crashes and severe crashes, and impacts general traffic crashes as a whole. CONCLUSIONS: This study suggests the following should be considered in pre-signal installation on intersections. 1) U-turns allowed in the front and rear 2) A high number of roads that connect to the intersection 3) Many right-turn traffic flows 4) Crosswalks installed in the front and rear 5) Insufficient left-turn lanes compared to left-turn traffic flows or no left-turn-only lane.

Small cell osteosarcoma of bone, which was first described in 1979, is an unusual variant of osteosarcoma. Osteoid production by tumor cells is frequently focal or minimal, making the differential diagnosis with other small round cell tumors of bone difficult. Here, we present a rare case of small cell osteosarcoma of the mandible appearing as bony bulging mass in 31-year-old male who has neither tenderness nor paresthesia. Histologically, the tumor contains hypercellular cartilage and abnormal osteoid associated with small round to ovoid malignant cells. Awareness of small cell osteosarcoma should be emphasized because it has worse prognosis than both other small round cell tumor and conventional osteosarcoma.

During the laser-assited endoscopic surgery, the laser light is delivered to the deep tissue or the internal organ using a light transmitting delivery system. It is necessary to modify the direction of the light emission at the distal end of fiber tip for some application of in laser-assisted surgery. The homemade diffusing fiber and the forward firing fiber are used for the endoscopic delivery system of the continuous IR laser into the water rich tissue. The beam emission and the laser-assisted ablation and coagulation pattern were compared for two distinctive fiber systems. The diffusing fiber produced cavity and coagulation zone more or less a circular shape, while the forward fiber produced an elongated cavity and coagulation region. The diffusing fiber produced wider and shorter coagulation and cavity zone compared to that of forward-firing fiber

The ossifying fibroma (OF), with the microscopic features of trabuclae or spherules of bone or cementum-like material in a cellular fibrous connective tissue stroma, is one of the most common benign fibro-osseous lesions in the jaw bones. The OF often occurs in patients from 20 to 40 years of age, which is a definite female predilection. The mandibles are involved far more often than the maxillas, especially the pre-molar and molar regions. It is slow-growing, bone producing, asymptomatic and well-demarcated. The OF is a disorder of odontogenesis or osteogenesis ascribed to bone marrow stroma cells (BMSCs) abnormality. However, the detailed mechanisms of OF’s oncogenesis, cytodifferentiation, and tumor progression remain unknown. In this article, we reported a huge central OF on the anterior mandible. The lesion was enucleated and peripheral ostectomy was done via intraoral approach and reconstructed with vascularized iliac block bone graft. After 25 months of follow up, the tumor had not recurred. This case shows that OF may be successfully treated by conservative surgical enucleation and peripheral ostectomy.

본 연구에서는 선박 안전 운항을 위해 개발된 실시간으로 전방 관측 항해 장비의 개발 결과와 해상 시운전 결과를 기술한다. 개발된 장비는 Pan/ Tilt에 고성능 카메라와 레이져 거리 측정기를 장착하여 선박 항해 구간 내 주간 위해 요소의 관측하여 사람 시야 형태의 화상 데 이터로 모니터 할 수 있다. 개발된 항해 장비는 선급 성능 검증을 위해 실습선 새유달호 장착하여 해상 시운전을 수행하였고, 그 결과를 바탕으 로 선급 인증을 위한 환경 평가와 성능 평가안을 제시하였다.