• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.74-79
• /
• 2005

In this paper, we propose a novel approach to decentralized motion planning and conflict-resolution for multiple mobile agents working in an environment with unexpected moving obstacles. Our proposed motion planner has two characteristics. One is a real-time collision prognosis based on modified collision map. Collision map is a famous centralized motion planner with low computation load, and the collision prognosis hands over these characteristics. And the collision prognosis is based on current robots status, maximum robot speeds, maximum robot accelerations, and path information produced from off-line path planning procedure, so it is applicable to motion planner for multiple agents in a dynamic environment. The other characteristic is that motion controller architecture is based on potential field method, which is capable of integrating robot guidance to the goals with collision avoidance. For the architecture, we define virtual obstacles making delay time for collision avoidance from the real-time collision prognosis. Finally the results obtained from realistic simulation of a multi-robot environment with unknown moving obstacles demonstrate safety and efficiency of the proposed method.

• Journal of Chest Surgery
• /
• v.18 no.2
• /
• pp.341-344
• /
• 1985

Carcinosarcoma is an unusual and rarest neoplasm in man, consisting of carcinomatous parenchyme and sarcomatous stroma. Two clinical types of carcinosarcoma were present. One type of tumor was centrally located [endobronchial type], infrequent metastasis, and better prognosis than parenchymal type. The other type was peripherally located [parenchymal type], frequent metastasis, and poor prognosis. The histogenesis of carcinosarcoma is many hypothesis, but controversial; 1] sarcomatous degeneration of stroma, 2] intermingling of simultaneously arising carcinoma & sarcoma, 3] multiple primary tumor, 4] blastomatous changes in hamartoma, 5] stromal reaction to squamous cell carcinoma, 6] true & collision carcinosarcoma. In this case, 52 year-old male patient was hospitalized due to intermittent hemoptysis & known pulmonary lesions. Since 1968, chest PA showed round haziness within cyst & multiple cyst on RUL & RLL. Radical pneumonectomy was performed and histopathology showed carcinosarcoma, surrounded by bronchial epithelium. The patient maintain general well-being without clinical evidence of recurrence till now.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.37 no.3
• /
• pp.328-337
• /
• 2010

The purpose of this study was to research the traumatized primary teeth and investigate following factors: sex, age, cause, place and time(of the year) of injury, elapsed time, area and type of injury, dental treatment and prognosis. The analysis includes total of 1533 traumatized primary teeth from 758 children aging from 6 months to 6 years(mean age: 2.8) from 2003 to 2007. The result follows : 1. The children of age between 1-2 and 2-3 were involved in the largest number of injuries in both sexes with boy/girl ratio of 1.77:1(p<0.001). 2. Fall and collision were the main causes of traumatic dental injury, especially in younger children(p<0.05). Places of injury occurrence varied: home, outdoors, and kindergarten. Warm climate accounts for frequent outdoor injuries in May, September and October(p<0.001). 3. Most of the children visited dental clinic within 24 hours of the injury(77.6%). From March to September, dental trauma occurrences were distributed evenly, except for Winter period(p<0.001). 4. Upper central incisors were the most commonly affected teeth, and the injuries usually involved 1 tooth or 2 teeth. 5. Periodontal tissue injuries dominated and subluxation was the most common type. Lateral luxation, enamel fracture, intrusion and root fracture followed.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.28 no.4
• /
• pp.600-612
• /
• 2001

The purpose of this study is concerned with an investigation of the actual condition of traumatic injuries of teeth and supporting structures in children to set up possible criteria for prevention and treatment of injured teeth. The materials consisted of the clinical records of 431 traumatically injured teeth of 212 children, accumulated during two years from the first of April in 1998 to the end of March in 2000, supplied from the Dept. of Pediatric Dentistry, Chonbuk National University Hospital. The incidence of injuries in boys was extremely high for permanent teeth, twice as high as in girls. Accidents to primary teeth were most common from 1 to 2 years of age and to permanent teeth were most from 8 to 9 years of age. The most common cause of trauma was a fall for both primary and permanent teeth, followed by collision. The anterior teeth in maxilla was most frequently affected by trauma in both the primary and permanent teeth. The most common type of trauma were loosening for the primary teeth, followed by luxation types which included the intrusion, displacement and extrusion and complete avulsion types. For the permanent teeth, the most common type of trauma were tooth fracture. The most common trauma of soft tissue was laceration of upper lip, lower lip and gingiva of maxilla Concerning treatment at the first visit, primary teeth with only loosening and concussion were not usually treated. Permanent teeth were often treated by crown restorations for crown fractures and by endodontic procedures for pulpal exposure. Though we could elucidate actual condition of traumatic injuries of teeth in children, we should make a follow-up survey to ensure the prognosis of injured teeth and establish the most desirable criteria for traumatized teeth in children.