• Journal of Chest Surgery
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• v.42 no.2
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• pp.244-247
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• 2009

A left atrial appendage aneurysm is a very rare medical condition which can develop by an inflammatory reaction or a degenerative change. If there is no accompanying anomaly, a left atrial appendage is considered a congenital disease. The majority of left atrial appendage aneurysms are detected incidentally because they usually do not cause any symptoms. Surgery is indicated, even for asymptomatic patients, because of the risk of life-threatening complications, such as atrial fibrillation, supraventricular tachycardia, systemic embolization, and cardiac arrest. Left atrial appendage aneurysms are usually treated by a median sternotomy with extracorporeal circulation, especially if the aneurysm has a broad base or contains a thrombus, but can treated by thoracotomy without extracorporeal circulation. We report a case of a successfully treated left atrial appendage aneurysm that was misdiagnosed as a partial pericardial defect without extracorporeal circulation in a 13-year old child.

• Journal of Chest Surgery
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• v.39 no.2 s.259
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• pp.162-165
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• 2006

The innominate artery aneurysm is an uncommon entity. A 36-year-old man was transferred to our hospital because of incidental finding of right superior mediastinal mass. He had a history of blunt chest trauma due to automobile accident 16 years earlier. Computed tomography scanning demonstrated 5-cm sized sacular aneurysm with thrombus at the innominate artery. The prosthetic bifurcated bypass grafting from the ascending aorta to the right common carotid artery and right subclavian artery was performed under the moderate hypothermic cardioplumonary bypass. We report a successful surgical treatment for a rare case of the innominate artery aneurysm.

• Journal of Chest Surgery
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• v.29 no.5
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• pp.581-584
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• 1996

Reexpansion pulmonary edema is a rare complication of the treatment of lung collapse secondary to pneumothordx, pleural effusion, or atelectasis but occasionally life threatening. Generally, reexpansion pulmonary edema is believed to o cur only when a chronically collapsed lung is rapidly reexpanded by evacuation or large amounts of air or fluid. This complication is heralded by tachypnea, unilateral rales, and profuse expectoration of frothy secretion within several hours of reexpansion. Increased dur- ation of pneumothorax and the use o( suction are important factors in the generation of reexpansion pulmonary edema. We had experienced 3 cases of reexpansion pulmonary edema. In the two cases the pneumothorax had been present for several days, and, after insertion of a chest tube, pulmonary edema developed unilaterally but improved with supplemental oxygen. In the third case, massive pleural effusion was present. and, after insertion of a chest tube, pulmonary edema developed unilaterally, followed by cardiac arrest. He died of pulmonary edema inspire of resuscitation.

• Journal of KIISE:Databases
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• v.31 no.4
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• pp.384-394
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• 2004

Recently, to relieve the performance degradation caused by the bottleneck between CPU and main memory, cache conscious multi-dimensional index structures have been proposed. The ultimate goal of them is to reduce the space for entries so as to widen index trees and minimize the number of cache misses. The existing index structures can be classified into two approaches according to their entry reduction methods. One approach is to compress MBR keys by quantizing coordinate values to the fixed number of bits. The other approach is to store only the sides of minimum bounding regions (MBRs) that are different from their parents partially. In this paper, we propose a new index structure that exploits the properties of the both techniques. Then, we investigate the existing multi-dimensional index structures for main memory database system through experiments under the various work loads. We perform various experiments to show that our approach outperforms others.

• Journal of Yeungnam Medical Science
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• v.10 no.1
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• pp.179-189
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• 1993

It has recently become possible to record electrical activity originating from abnormally conducting myocardium from the body surface with high - gain amplification and averaging technique. These signals, which result from delayed ventricular activation(late potentials), have been recorded in patients with documented ventricular tachyarrythmia. Several electrode lead system for detecting ventricular late potential were introduced. Pyramidal electrode lead system(PLS) is useful. Also interpretation of SAECG in the young could be of value in detecting those at risk for episodic ventricular tachycardia, but suffer from a lack of data in normal young people. Selection of subjects : For this study, normal healthy young adult volunteers (age: mean 24 years) were recruited from the medical students at Yeungnam University Hospital, Internal Medicine. Twenty fourths male and seventeenths female subjects were selected. All subjects had normal resting ECGs as judged from both the standard 12 channel lead and echocardiography, and none had a history of cardiovascular disease. All subjects were considered to be in good general physical condition. Signal-averaged electrocardiography : In order to obtain low noise recordings with a small number of averaging cycles, all subject ware asked to relax completely in the supine position. Silver/silver chloride electrodes were attached after the skin was cleaned with alcohol, to constitute classic flank lead system(FLS) and pyramidal lead system(PLS). Signals were recorded and processed using a commercially available microprocessor-augmented ECG cart(Marquette Electronics, USA) suitable for portable bedside recording. There was no difference between normal values, determined by FLS and PLS at high pass filtering of 25 Hz and 80 Hz, but significant, difference was found in HFLAD and RMS-40 of 40 Hz(p<0.05). These results will provide a basis for interpretations of SAECG, determined by FLS and PLS in healthy young adults with normal QRS duration.

• 한국HCI학회:학술대회논문집
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• 2007.02b
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• pp.70-77
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• 2007

모바일 IT와 무선인터넷의 발달에 따라 디지털 컨텐츠를 담는 뉴미디어로서의 휴대폰의 가능성은 점차 확대되고 있으며, 모바일 컨텐츠 시장도 급속도로 성장하고 있다. 무선인터넷의 발달은 유선 인터넷 컨텐츠를 무선으로 확장하게 하였으며, 장소기반 관광 정보 (Location Based Information) 서비스가 우선적으로 구축되고 있다. 그러나, 현재 모바일 기기로 서비스되고 있는 대부분의 관광정보는 관광지에 대한 간단한 설명, 교통편, 숙박, 음식점 등 매우 실용적이고 일반적이어서 편리하긴 하지만, 그다지 사용하고 싶은 매력은 없는 정보에 그치고 있다. 본 연구는 기술적으로 진화하고 있는 유비쿼터스 도시 환경에서 모바일을 활용하여 어떠한 새로운 형태의 관광 컨텐츠가 가능해질 수 있을까 하는 질문에서 출발하였다. 본 논문은 정보통신연구 진흥원의 지원을 받아 진행했던 지역의 역사, 문화 정보 전달을 위한 모바일 투어 게임 "타임트렉" 프로토타입 개발에 관한 리서치, 컨셉, 프로세스를 정리한 것이다. "타임트렉" 프로젝트에서 추구했던 방향은 문화적, 역사적으로 중요한 장소를 투어하면서 모바일 미디어를 활용하여 보다 깊은 역사, 문화 정보를 새롭고 재미있는 방법으로 전달하고자 하는 것이었다. 특히, 사용자의 보다 적극적인 참여와 흥미유발을 위해 시간여행 능력을 가진 탐정이 과거로 시간여행을 통해 사건을 해결하는 롤플레잉 스토리 기반 게임과 물리적 장소에서 답을 찾아야 하는 오프라인 퀘스트 게임의 형식을 포함하는 모바일 투어 게임형태로 구축하였다. 이렇게 함으로써 관광객들에게 보다 그 장소에 대해 알고 싶어 하는 흥미를 유도하고 투어를 완료하게 유도함으로써 만족스럽고 새로운 관광 경험을 제공하는 것을 목적으로 하였다. 새로운 타입의 모바일 관광서비스의 프로토타입 개발에 있어 중점을 두었던 부분은 역사적으로 중요한 장소를 워킹 트레일로 구성하고 그 장소가 가지는 기본적인 문화, 역사적 정보에 오락적 요소(스토리와 게임 요소)를 자연스럽게 혼합하여 흥미로운 컨텐츠를 만들는 것이었으며, 또한 모바일이 가진 위치기반 서비스 기능을 활용하여 효과적으로 컨텐츠를 적재적소에 제시하는 인터페이스 구현에 중점을 두었다. 논문에서는 먼저, 기존의 국내외 모바일 관광정보서비스의 사례 및 연구 동향을 분석하고, 이에 따라 설정한 "타임트렉" 프로젝트의 방향성과, "타임트렉" 프로젝트에서 개발했던 프로토타입에 대하여 요약, 설명하였으며, 사용자 테스트 과정을 기술하였다. 그리고 마지막으로, 시장 세분화에 따른 관광 정보 서비스의 엔터테인먼트화 전략에 대해 논의하였다. 본 연구에서 시도했던 지역의 역사, 문화 관광을 위한 LBS 모바일 기술과 스토리, 게임 등 엔터테인먼트 요소의 결합은 관광객들에게 새로운 형태의 즐거운 관광 경험을 창출할 수 있으며, 관광 산업과 모바일 컨텐츠 산업의 결합이라는 새로운 접근의 장을 개척할 수 있을 것이다.

• Journal of Chest Surgery
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• v.35 no.1
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• pp.11-19
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• 2002

Background: Ischemia-reperfusion myocardial injury is an important factor to determine the early and the late mortality of transplanted patients. Recently, modulation of the cytosolic NADH/NAD+ ratio by Pyruvate and aspartate was tested to Protect the heart from ischemia-reperfusion injury. Material and Method: We added pyruvate and aspartate to the University of Wisconsin solution, and evaluated their effect on myocardial protection. We used 16 piglet(age 1 to 3 days) hearts. Eight hearts were arrested with and stored in the University of Wisconsin solution(UW solution) for 24 hours(control group), and the other eight hearts were arrested with and stored in the modified UW solution added pyruvate(3mmol/L) and aspartate(2 mmol/L)(test group). All hearts underwent modified reperfusion with blood cardioplegic solution followed by conversion to a left-sided working model with perfusion from a support pig. And then, we measured stroke work index(SWI), high-energy phosphate stores, and myocardial water content of the hearts. SWI was calculated at left ventricular end-diastolic pressures of 3, 6, 9, and 12 mmHg after 60 and 120 minutes reperfusion, respectively, Result: At 60 minutes and 120 minutes after reperfusion, SWI was higher in the test group than in the control group significantly. The levels of AMP, ADP, ATP of the test group were also higher. But, the creatine phosphate level and myocardial water content were similar in the two groups. Conclusion: From these results, we could Prove that pyruvate and aspartate enhance cardiac contractility and high-energy phosphate stores after ischemia.

• Journal of Chest Surgery
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• v.38 no.1 s.246
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• pp.13-22
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• 2005

It has been known that pulsatile flow is physiologic and more favorable to tissue perfusion than nonpulsatile flow. The purpose of this study is to directly compare the effect of pulsatile versus nonpulsatile blood flow to renal tissue perfusion in extracorporeal circulation by using a tissue perfusion measurement system. Material and Method: Total cardiopulmonary bypass circuit was constructed to twelve Yorkshire swines, weighing 20$\~ $30 kg. Animals were randomly assigned to group 1 (n=6, non pulsatile centrifugal pump) or group 2 (n=6, pulsatile T-PLS pump). A probe of the tissue perfusion measurement system $(QFlow^{TM}-500)$ was inserted into the renal pa­renchymal tissue. Extracorporeal circulation was maintained for an hour at a pump flow of 2 L/min after aortic cross-clamping. Tissue perfusion flow of the kidney was measured at baseline (before bypass) and every 10 minutes after bypass. Serologic parameters were collected at baseline and 60 minutes after bypass. Result: Baseline parameters were not different between the groups. Renal tissue perfusion flow was substantially higher in the pulsatile group throughout the bypass (ranged 48.5$\~$ 64 in group 1 vs. 65.8$\~$88.3 mL/min/100 g in group 2, p=0.026$\~$ 0.45) The difference was significant at 30 minutes bypass $(47.5{\pm}18.3\;in\;group\;1\;vs.\;83.4{\pm}28.5$ mL/min/100 g in group 2, p=0.026). Serologic parameters including plasma free hemoglobin, blood urea nitrogen, and creatinine showed no differences between the groups at 60 minutes after bypass (p=NS). Conclusion: Pulsatile flow is more beneficial to tissue perfusion of the kidney in short-term extracorporeal circulation. Further study is suggested to observe the effects to other vital organs or long-term significance.

• Journal of Chest Surgery
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• v.31 no.9
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• pp.827-836
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• 1998

Background: Effective cardiopulmonary resuscitation (CPR) should provide acceptable hemodynamics for the vital organs during cardiac arrest and early restoration of spontaneous circulation that guarantees long-term, neurologically intact survival. CPR using heart-lung bypass has been suggested as an option for that use. This study was designed to determine the effectiveness of standard CPR techniques, closed-vs. open-chest CPR, which could be used in the future study verifying the role of heart-lung bypass CPR. Material and Method: By using adult mongrel dogs, closed-chest CPR (CCCPR, n=4) and open-chest CPR (OCCPR, n=5) were compared with respects to hemodynamics, restoration of spontaneous circulation(ROSC), and survival. Ventricular fibrillation-cardiac arrest (VF-CA) was induced by electrical shock in all animals. After 4 minutes of cardiac arrest, basic life support (BLS) was applied for 15 minutes and followed by advanced life support (ALS). ALS was maintained until achi ving ROSC but not longer than 30 minutes regardless of the recovery. Resuscitation procedures in either group were standardized by adopting the protocol of American Heart Association. Result: Prearrest baseline hemodynamic data was not different between two groups. During resuscitation, substantially higher systolic pressure was maintained in OCCPR group than in CCCPR group (45$\pm$15 vs. 33$\pm$11 mmHg during BLS, 83$\pm$36 vs. 44$\pm$15 mmHg during ALS; p=NS). Mean pulmonary arterial pressure went up to the level of mean systemic arterial pressures in CCCPR group and to half of that in OCCPR group, and had kept higher in CCCPR group throughout CPR (32$\pm$10 vs. 22$\pm$4 mmHg during BLS and 32$\pm$15 vs. 24$\pm$10 mmHg during ALS; p=NS). ROSC was obtained in 4 of 5 dogs receiving open-chest CPR and 2 of 4 closed-chest CPR. Prolonged survival was noted in all dogs in OCCPR group (6 to 1440 hours) but not in CCPR group (p<.05). Conclusion: These findings indicate that open-chest CPR can be more effective t maintain hemodynamics during cardiac arrest and to obtain restoration of spontaneous circulation and survival. Further experiment will be designed to compare heart-lung bypass CPR with open-chest CPR.

• The Korean Journal of Air & Space Law and Policy
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• v.27 no.2
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• pp.211-241
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• 2012

The Draft International Code of Conduct for Outer Space Activities officially proposed by the European Union on the occasion of the 55th Session of the United Nations Peaceful Uses of the Outer Space last June 2012 in Vienna, Austria is to fill the lacunae of the relevant norms to be applied to the human activities in the outer space and thus has the merit our attention. The missing elements of the norms span from the prohibition of an arms race, safety and security of the space objects including the measures to reduce the space debris to the exchange of information of space activities among space-faring nations. The EU's initiatives, when implemented, cover or will eventually prepare for the forum to deal with such issues of interests of the international community. The EU's initiatives begun at the end of 2008 included the unofficial contacts with major space powers including in particular the USA of which position is believed to have been reflected in the Draft with the aim to have it adopted in 2013. Although the Code is made up of soft law rather than hard law for the subscribing countries, the USA seems to be afraid of the eventuality whereby its strategic advantages in the outer space will be affected by the prohibiting norms, possibly to be pursued by the Code from its current non-binding character, of placing weapons in the outer space. It is with this trepidation that the USA has been opposing to the adoption of the United Nations Assembly Resolutions on the prevention of an arms race in the outer space (PAROS) and in the same context to the setting-up of a working group on the arms race in the outer space in the frame of the Conference on Disarmament. China and Russia who together put forward a draft Treaty on Prevention of the Placement of Weapons in Outer Space and of the Threat or Use of Force against Outer Space Objects (PPWT) in 2008 would not feel comfortable either because the EU initiatives will steal the lime light. Consequently their reactions are understandably passive towards the Draft Code while the reaction of the USA to the PPWT was a clear cut "No". With the above background, the future of the EU Code is uncertain. Nevertheless, the purpose of the Code to reduce the space debris, to allow exchange of the information on the space activities, and to protect the space objects through safety and security, all to maximize the principle of the peaceful use and exploration of the outer space is the laudable efforts on the part of EU. When the detailed negotiations will be held, some problems including the cost to be incurred by setting up an office for the clerical works could be discussed for both efficient and economic mechanism. For example, the new clerical works envisaged in the Draft Code could be discharged by the current UN OOSA (Office for Outer Space Affairs) with minimal additional resources. The EU's initiatives are another meaningful contribution following one due to it in adopting the Kyoto Protocol of 1997 to the UNFCCC (UN Framework Convention on the Climate Change) and deserve the praise from the thoughtful international community.