• Journal of Trauma and Injury
• /
• 제34권4호
• /
• pp.279-283
• /
• 2021

Traumatic spinal cord infarction is a rare condition that causes serious paralysis. The regulation of spinal cord blood flow in injured spinal cords remains unknown. Spinal cord infarction or ischemia has been reported after cardiovascular interventions, scoliosis correction, or profound hypotension. In this case, a 52-year-old man revisited the emergency center with motor and sensory abnormalities in all four extremities 56 hours after a motor vehicle collision. Despite the clinical presentation and imaging examination, there were no specific findings on the patient's first visit to the trauma center. Cervical spine computed tomography angiography showed a narrow vertebral artery, and diffusion-weighted imaging revealed spinal cord infarction from C3 to C5 with high signal intensity. It should be kept in mind that delayed-onset spinal cord infarction may occur in minor or major trauma patients as a result of head and neck injuries.

• 한국도로학회논문집
• /
• 제11권2호
• /
• pp.195-203
• /
• 2009

본 연구는 교통사고의 발생 유형과 교통사고 심각도(Severity)와의 관계를 규명함으로써 위험유형을 제시하고, 운전자 특성과 교통사고의 관계를 규명하고자 하였다. 교통사고 유형을 여덟 가지로 세분하고, 결과의 객관성 확보를 위해 안전벨트 착용여부를 추가하여 상해정도와의 관계를 분석하였으며, 위험그룹의 분류를 위한 운전자의 특성은 성별, 차종, 연령 등을 대상으로 하였다. 카테고리 자료의 분석을 위하여 로그-선형 모형 및 로짓 모형을 사용하였다. 분석결과 사고유형과 심각도와의 관계에서는 정면충돌 사고와 앞지르기시, 우회전시 사고가 부상 또는 사망사고에 연루될 가능성이 높았다. 위험그룹 분석에서는 20세 미만의 이륜차 운전자, 41세에서 50세까지의 택시 운전자가 가장 위험한 집단으로 분석되었으며 또한 남자보다는 여자가 승용차와 중형화물 등에 관계되었을 때 더 위험한 것으로 분석되었다. 따라서 교통사고 발생시 인명 피해를 줄이기 위해서는 정면충돌 사고와 앞지르기시, 우회전시 발생하는 사고를 줄일 수 있는 방안이 연구되어야 하고, 교통사고 취약계층으로 분석된 위험그룹에 대한 교통안전 교육 및 단속이 강화되어야 할 것이다.

• 대한기계학회논문집A
• /
• 제39권10호
• /
• pp.1063-1068
• /
• 2015

본 논문에서는 도시철도차량의 타고오름 평가를 위한 충돌시뮬레이션 기법을 제안하였다. 시뮬레이션모델은 대차의 동적 거동을 표현하는 대차 동역학 모델과 붕괴거동을 표현할 수 있는 차체 유한요소 모델로 구성된다. 유럽 및 국내 충돌안전규정의 타고오름 평가를 위해 40 mm 오프셋 정면충돌 사고 각본에 따른 시뮬레이션을 수행하여 충돌 후 차체의 구조적 거동과 차체와 연계된 대차 모델의 동적 거등을 확인하였으며 타고오름 판단기준인 윤축의 상승거리로 타고오름을 평가하였다. 최종적으로 본 연구에서 제안한 시뮬레이션 기법을 적용하면 도시철도차량 충돌안전규정에 따라 충돌사고 시 타고오름에 대하여 평가할 수 있음을 확인하였다.

• 한국자동차공학회논문집
• /
• 제22권4호
• /
• pp.10-19
• /
• 2014

Despite the movement of safe traffic by the Korean government to reduce deaths in traffic accidents, the casualties increase year by year. In particular, more and more accidents and casualties are reported from car collisions from the back of the vehicles parked for managing traffic accidents on the road, cleaning main roads and medial strips, repairing roads. In order to response to these accidents, the government should take protective measures for road users. In the last decade, seventy-one cases have been reported to occur during highway repair and maintenance. As a result, eight persons were killed and seventy-six were injured, showing the high death rate of 11.3 percent. Therefore, it seems urgent to take some actions against it. The United States and European countries legislate that vehicles of road repair and maintenance should be mandatorily equipped with shock absorber at the back. Korea, however, does not have such legislative measures, which are needed at this time to protect workers on the road. This study compares the performance of the traditional shock absorber for road maintenance vehicles with that of the rear safety guard using air bag, manufactured in accordance with related laws in Korea. Based on the results of the 60km/h rear collision test, this paper proposes improvements in related laws and regulations in an attempt to reduce casualties.

• 한국정밀공학회지
• /
• 제25권8호
• /
• pp.80-87
• /
• 2008

This paper investigated into the impact characteristics of the stainless sheet with thickness of 0.7 mm on the stretching boundary condition through three-dimensional finite element analysis. High speed tensile tests were carried out to obtain strain-stress relationships with the effects of the strain rate. The FE analysis was performed by the ABAQUS explicit code. In order to improve an accuracy of the FE analysis, the hyper-elastic model and the damping factor were introduced. Through the comparison of the results of the FE analyses and those of the impact tests, a proper FE model was obtained. The results of the FE analyses showed that the absorption rate of energy maintains almost 82.5-83.5% irrespective of the impact energy level and the diameter of the impact head. From the results of FE analyses, variations of stress, strain, dissipation energy, strain energy density, and local deformation characteristics in the stainless sheet during the collision and the rebound of the impact head were quantitatively examined. In addition, it was shown that the fracture of the specimen occurs when the plastic strain is 0.42 and the maximum value of the plastic dissipation energy of the specimen is nearly 1.83 J.

• 한국항행학회논문지
• /
• 제13권4호
• /
• pp.551-558
• /
• 2009

에너지 효율성 초점이 맞추어진 대부분의 클러스터링 기법에서 클러스터 내에서 단일의 클러스터를 채용함으로써 클러스터 헤드의 에너지 소비가 급격히 증가 할 수 있다. 최근, 이러한 단점을 개선하기 위해 데이터 병합 기능 헤드와 데이터 전송 기능 헤드로 구분하는 2-계층 클러스터 기법은 클러스터 내에서 클러스터 헤드의 에너지 소비를 분산시켰다. 그러나 이러한 구조는 한 클러스터 내에 존재하는 두 개 헤드 사이에 독립적인 영역구분이 없는 단지 논리적인 영역이므로 많은 메시지 충돌과 전송 지연이 발생한다. 이러한 문제점을 해결하기 위해, 본 논문에서는 노드의 위치정보와 클러스터 반경을 이용해 한 클러스터에 속한 두 계층을 독립적으로 명확히 분할할 수 있는 분리된 2-계층 라우팅기법을 제시한다. 제안하는 스킴에서는 각 계층에 속하는 멤버노드 수에 대한 균등분포를 통해 부하의 분산을 보장한다. 제안한 기법은 기존의 DLS 기법보다 메시지 충돌문제를 50% 개선하였고, 네트워크의 수명도 DLS와 LEACH 등에 비해 약 10% 개선하였다.

• 한국응용과학기술학회지
• /
• 제23권2호
• /
• pp.147-152
• /
• 2006

The accidents occurred by unstable material which is easily exploded or burnt up were caused by heat and collision under the condition of relatively low temperature without oxygen, have been reported frequently. However, the amount of the unstable material is getting higher by development of fine ceramic research area even though its dangerous characteristic is disregarded. This research studied a heat stability and measured boiling point of various carpet material. Carpet has been used in home as well as general indoor usage. Now a day, carpet material which is hardly burnt has been on commercial, but its detailed unstable conditions is not mentioned. This research reports the measurement of the initial temperature of generation heat and heat-radiation change on differential scanning calorimeter (DSC). The DSC data of nylon bulked continuous filament (N-BCF) yam 100%, nylon (NY), poly propylene (PP), and a new material named polytrimethylene terephthalate (PTT) are studied and researched about the effect of them using TGA, furnace, and direct-burning experiment.

• 한국도로학회논문집
• /
• 제15권4호
• /
• pp.135-146
• /
• 2013

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.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2014년도 추계학술대회
• /
• pp.245-246
• /
• 2014

This paper suggests the navigation information display system which is based on augmented reality technology and especially focuses on image analysis technology. Navigator has to always confirm the information from marine electronic navigation devices and then they compare with the view of outside targets of the windows. During this 'head down' posture, they feel uncomfortable and sometimes it cause near-accidents such as collision or missing objects, because he or she cannot keep an eye on the front view of windows. Augmented reality can display both of information of virtual and real in a single display. Therefore we tried to adapt the AR technology to help navigators and have been studied and developed image pre-processing module as a previous research already. To analysis the outside view of the bridge window, we have extracted navigational information from the camera image by using image processing. This paper mainly describes about recognizing ship feature by haar-like feature and filtering region of interest area by AIS data, which are to improve accuracy of the image analysis.

• 천문학회보
• /
• 제39권2호
• /
• pp.89-89
• /
• 2014

While the current consensus view holds that galaxy mergers are commonplace, it is sometimes speculated that Globular Clusters (GCs) may also have undergone merging events, possibly resulting in massive objects with a strong metallicity spread such as Omega Centauri. Galaxies are mostly far, unresolved systems whose mergers are most likely wet, resulting in observational as well as modeling difficulties, but GCs are resolved into stars that can be used as discrete dynamical tracers, and their mergers might have been dry, therefore easily simulated with an N-body code. It is however difficult to determine the observational parameters best suited to reveal a history of merging based on the positions and kinematics of GC stars, if evidence of merging is at all observable. To overcome this difficulty, we investigate the applicability of supervised and unsupervised machine learning to the automatic reconstruction of the dynamical history of a stellar system. In particular we test whether statistical clustering methods can classify simulated systems into monolithic versus merger products. We run direct N-body simulations of two identical King-model clusters undergoing a head-on collision resulting in a merged system, and other simulations of isolated King models with the same total number of particles as the merged system. After several relaxation times elapse, we extract a sample of snapshots of the sky-projected positions of particles from each simulation at different dynamical times, and we run a variety of clustering and classification algorithms to classify the snapshots into two subsets in a relevant feature space.