ROS Composition에서 페이지 수준 격리를 위한 메모리 할당 방법

학위논문(석사) -- 서울대학교대학원 : 공과대학 전기·정보공학부, 2023. 2. 백윤흥.One of the most widely used middleware in robot application development is the Robot Operating System (ROS). As ROS composition methods have emerged, it has become possible to execute multiple nodes concurrently in a single process. However, when multiple nodes are composed into a single process, multiple independent nodes share the same memory space, and therefore dynamically allocated memory chunks of different nodes are intermixed, regardless of the page boundary. In order to apply page level isolation, this paper introduces a memory allocation method to dynamically allocate memory chunks on separate regions for each node, even on precompiled node binaries. In this method, the memory requests are redirected to a specially designed allocator, and upon a memory request, on which region the memory request must be handled is determined using additional information obtained through tracing the required information.Robot Operating System (ROS)는 로봇 애플리케이션을 만드는데 널리 쓰이는 미들웨어이다. ROS composition 방법이 등장하면서, 하나의 프로세스 내에 여러 개의 노드를 같이 실행하는 것이 가능 해졌다. 그러나, 하나의 프로세스 내에 여러 개의 노드가 존재할 때는 모든 노드가 하나의 메모리 공간을 사용하므로, 각 노드에 동적으로 할당된 메모리 개체들이 페이지의 경계에 상관없이 무질서하게 배열된다. 본 논문에서는 ROS composition 프로세스에서 페이지 수준 격리를 적용하기 위해서, 각 노드에 동적으로 메모리를 할당할 때 서로 다른 영역에 메모리를 할당하도록 하는 메모리 할당 방법을 제안한다. 본 논문에서 제안하는 방법은 기존에 컴파일 된 노드 바이너리에 대해서도 적용이 가능하다. 해당 방법에서는 메모리 할당 및 해제 요청을 특수하게 설계된 메모리 할당자로 보내어 처리한다. 이 때, 어느 영역에서 해당 요청을 처리해야 하는지 결정하기 위해 필요한 정보를 추적하여 확보하며, 이를 이용하여 각 요청을 적절하게 처리한다.제 1 장 Introduction 1 제 2 장 Background 3 제 1 절 Robot Operating System (ROS) 3 제 2 절 Structure of ROS Process 4 제 3 절 Page Level Isolation 5 제 4 절 Memory Allocator 5 제 3 장 Design and Implementation 7 제 1 절 Memory Request Trampoline 8 제 2 절 Porting a Memory Allocator 10 제 3 절 Execution Context Tracer 11 제 4 절 Memory Tracer 12 제 4 장 Evaluation 14 제 1 절 Proof of Concept Experiment 14 제 2 절 Performance Evaluation 16 제 5 장 Conclusion 18 Reference 19 Abstract 20석

Appraisal of prehospital care by 119 squad

의학과/석사[한글] 최근 인구증가, 각종 사고 및 급성질환의 증가로 인한 응급환자의 증가에 따른 응급의료의 수요는 각 국가마다 커다란 사회문제로 대두되고 있다. 즉 증가하는 각종 응급환자에 신속히 대처하며, 초기에 효율적인 응급처치 및 응급후송을 시행할 수 있는 응급의료전달체계가 필요하게 되었다 본 연구의 목적은 서울 광진구에 위치한 2차 대학병원을 대상으로 119 구급대를 통해 내원한 환자의 구급일지와 의무기록 분석과 119 구급대원 대상의 설문을 이용하여 응급의료 체계의 주요 구성 요소인 병원 전 응급처치와 환자 예후 및 결과와의 관계, 구급일지기록의 정확성, 처치의 적정성 여부와 후송 중의 의료적인 문제점을 고찰하여 개선방향을 제안하는 데 있다. 이전의 연구들은 주로 응급의료체계의 현황에 대한 내용을 보고하였지만 본 연구에서는 병원전 처치와 환자 예후와의 관계, 환자의 진료 결과에 대한 되먹임이 구급대원들의 병원전 처치나 구급일지 작성에 미치는 영향을 알아보고, 효과적인 병원전 처치와 정확한 구급일지 작성에 대한 의견을 제시하고자 한다. 병원전 처치는 대부분 시행되고 있으나 제세동, 기관삽관 등의 경우는 대원들에 대한 교육과 법률적으로 응급구조사의 업무를 확실히 하여야 하며 구급일지의 경우는 제대로 기록이 안 되고 있으므로 수정이 필요하다고 보인다. 또한 의학적 관리를 위해서는 인터넷이나 다른 유무선 방식을 개발하여 효과적인 병원전 의사지도가 이루어지도록 해야 할 것이다. [영문]To study the assessment of prehospital care in the EMS system, the author studied 2,484 patients who had been transported by 119 squad from June 2002 to May 2003 and the result were summarized as followings ; 1. Among total 2,484 patients who transported, 1,271 were male(51.2%) and 1,213 were female(48.8%). The peak age was 2nd, 4th, 3rd decade. In the distribution of the happened place for ambulance, 59.4% were house, and the time for call were even distribution. 2. Decision of an chosed hospital is most common in the short distances. The causes of transportation were disease(51.2%), accident(37.7%). In the severity of patients, 36(1.5%) patients were classified into urgent, 671(27.0%) into emergent, 1,068(42.9%) into non-emergent. 3. The Assessment of prehospital treatment by emergency medical technician revealed that emergency treatment was 78.1%. But measuring blood pressure was only 10.2%, checking respiration rate was 19.3%. Prehospital care was limited to airway management, oxygen inhalation and immobilization. There was no case of the notification to emergency department or consultation to doctor. 4. Among 69 119 squad, male were 64(92.7%), female were 5(7.2%) and the peak age was 3rd decade(52.2%). They have experienced chest compression(100%), defibrillation via AED(47.8%) intubation (26.1%) in a year. 119 squads want to know the patients'' outcome(78.3%) but needs for direct medical control were low(56.5%). 5. Number of patients admitted were 731 case(29.4%), operated 60(2.4%), admitted ICU were 227(9.3%). For the patients with 3 grade triage method, 45.0% of emergent patients discharged, with AVPU method, 5.7% of alert patients admitted ICU, with modified ESI method, all of 1st group 62 patients were admitted ICU or expired, DOA. The present level of prehospital emergency care is very low and does not deviate from patients'' transportations. Since prehospital emergency care have an significant effect upon prognosis and lives of patients, the present emergency medical systems leave something to be desired or a new problem about the present emergency medical care is rising.ope

Chest injury following cardiopulmonary resuscitation: A prospective computed tomography evaluation

INTRODUCTION: Traumatic chest injuries may occur following cardiopulmonary resuscitation (CPR). The aim of this study was to address the frequency of injuries, especially rib and sternal fractures, and also to identify factors that contribute to post-CPR trauma. METHODS: This study was a prospective cross-sectional study conducted in the emergency departments (ED) of eight academic tertiary care centers. To evaluate injuries secondary to CPR, we performed chest computed tomography (CT) in patients who were successfully resuscitated from cardiac arrest. Contributing factors that might be related to injuries were also investigated. RESULTS: We enrolled 71 patients between 1 January 2011 and 30 June 2011. Rib and sternal fractures were diagnosed in 22 and 3 patients, respectively. Females were more susceptible to rib fracture (p=0.036). When non-physicians participated as chest compressors in the ED, more ribs were fractured (p=0.048). The duration of CPR and number of compressors were not contributing factors to trauma secondary to CPR. There was a wide variation in the frequency of rib fractures from hospital to hospital (0-83.3%). In high-risk hospitals (in which more than 50% of patients had rib fractures), the average age of the patients was higher, and non-physicians took part in ED CPR more often than they did at low-risk hospitals. CONCLUSION: The incidence of rib fracture following CPR was different in various hospitals. The presence of non-physician chest compressors in the ED was one of the contributing factors to rib fracture. Further studies on the influence of resuscitators and relation between quality of chest compression and CPR-induced injuries are warranted to reduce complications following CPR.ope

Effect of Induced and Spontaneous Hypothermia on Survival Time of Uncontrolled Hemorrhagic Shock Rat Model

We examined the hypothesis that mild hypothermia (rectal temperature 34℃) results in the same survival time, whether induced spontaneously or intentionally, during untreated, lethal, uncontrolled hemorrhagic shock in rats. Sixty-four Sprague-Dawley male rats were randomly assigned to normothermia (Nth) (n=19), spontaneous mild hypothermia (Sp.Hth) (n=25) or controlled mild hypothermia (Con.Hth) (n=20) groups. After blood withdrawal of 3 mL/100 g over 15 minutes, followed by 75% tail amputation under spontaneous breathing and light anesthesia by i.p. injection of pentobarbital sodium, rats were observed without fluid resuscitation or hemostasis for 180 minutes or until death. The initial temperature of the Nth group was artificially maintained throughout the experiment. For the mild hypothermia groups, the Sp.Hth group was exposed to ambient temperature while the Con. Hth group was actively cooled to a target rectal temperature of 34℃. In the Con.Hth group, all rats except one died before 180 minutes. All rats in the Nth group died within 38 minutes, and within 67 minutes in the Sp.Hth group. The average survival time was shortest in the Nth group at 20.3 ± 5.3 minutes, followed by the Sp.Hth group at 30.1 ± 13.5 minutes, and the Con.Hth group at 81.9 ± 39.8 minutes (p < 0.01). Tail bleed out volume was 0.51 ± 0.19, 0.26 ± 0.15 and 0.19 ± 0.12 mL/100 g in the Nth, Sp.Hth and Con.Hth groups, respectively (p < 0.05). In conclusion, spontaneous mild hypothermia did not prolong the survival time as much as controlled mild hypothermia in the rat model for untreated, lethal, uncontrolled hemorrhagic shock.ope