• 한국추진공학회지
• /
• 제24권2호
• /
• pp.35-42
• /
• 2020

최근 위성 발사체를 재사용하여 발사비용을 절감하려는 노력이 SpaceX를 비롯한 민간 기업에서 시도되어 많은 성공을 거둠으로써 재사용발사체가 발사체 시장의 큰 흐름이 되고 있다. 그러나 발사비용 측면에서 재사용발사체가 유리한 것인가에 대하여서는 논란의 여지가 여전히 존재하며, 재사용 발사체에 대한 개발 초기 단계에서 이에 대한 면밀한 검토가 필요하다. 본 연구에서는 재사용 발사체의 발사비용에 영향을 미치는 가격인자들에 대하여 발사비용의 민감도 분석을 수행한다. 민감도 분석의 기준은 임무중량 20톤의 소모성 발사체의 발사비용으로 하며, 발사비용의 계산에 사용된 비용추청관계식(CERs)은 TRANSCOST 등의 비용모델을 활용하여 계산한다. 주요 비용인자는 개발비용, 제작비용, 수리비용 및 재사용 가능 횟수로 한다.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권9호
• /
• pp.3741-3745
• /
• 2015

Background: A moderate dose of radiation is the recommended treatment for solitary plasmacytoma (SP), but there is controversy over the role of surgery. Our study aimed at comparing different treatment modalities in the management of SP. Materials and Methods: Data from 38 consecutive patients with solitary plasmacytoma, including 16 with bone plasmacytoma and 22 with extramedullary plasmacytoma, were retrospectively reviewed. 15 patients received radiotherapy alone; 11 received surgery alone, and 12 received both. The median radiation dose was 50Gy. All operations were performed as radical resections. Local progression-free survival (LPFS), multiple myeloma-free survival (MMFS), progression-free survival (PFS) and overall survival (OS) were calculated and outcomes of different therapies were compared. Results: The median follow-up time was 55 months. 5-year LPFS, MMFS, PFS and OS were 87.0%, 80.9%, 69.8% and 87.4%, respectively. Univariate analysis revealed, compared with surgery alone, radiotherapy alone was associated with significantly higher 5-year LPFS (100% vs 69.3%, p=0.016), MMFS (100% vs 51.4%, p=0.006), PFS (100% vs 33.7%, p=0.0004) and OS (100% vs 70%, p=0.041). Conclusions: Radiotherapy alone can be considered as a more effective treatment for SP over surgery. Whether a combination of radiotherapy and surgery improves outcomes requires further study.

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권11호
• /
• pp.6979-6983
• /
• 2013

Background: Oral lichen planus (OLP) is categorized as premalignant lesion although its malignant potential is a matter of controversy. The objective of this study was to investigate Ki67 expression in OLP, oral epithelial dysplasia and oral squamous cell carcinoma (OSCC). Materials and Methods: Expression of Ki67 was evaluated through immunohistochemistry (IHC) in groups of A (17 cases of epithelial hyperplasia), B (16 cases of OLP), C1 (10 cases of mild epithelial dysplasia), C2 (10 cases of severe epithelial dysplasia), D1 (10 cases of well-differentiated OSCC), and D2 (10 cases of poorly-differentiated OSCC). Results: There was a significant difference in Ki67 expression based on quantitative analysis among the six studied groups as well as group B compared bilaterally with groups C2, D1 and D2 (p< 0.0001). However, there was no significant difference between groups B and C1 or between groups D1 and D2 (p> 0.05). Conclusions: Based on the results of the present study it may not be possible to definitely consider malignant transformation potential for OLP. However, expression of Ki67 was significantly higher in OLP than that of epithelial hyperplasia with no significant difference from that of mild epithelial dysplasia. This should be considered by clinicians to carefully and regularly follow up OLP lesions to detect potential subtle changes at an early stage.

• 디지털융복합연구
• /
• 제13권4호
• /
• pp.357-368
• /
• 2015

사람들은 항상 사건들과 접하고 그것을 지각하며 산다. 우리는 이러한 광학 흐름의 결과로 볼 수 있는 사건들을 어렵지 않게 인지한다. 문제는 사람들이 어떻게 이러한 사건들을 인지하며 광학 흐름 중 어떠한 정보가 우리로 하여금 이러한 사건들을 인지하게 만드는 지이다. 운동이론학자들은 인간은 이러한 사건들을 생산함과 동시에 지각하기 때문에 말소리 지각이나 생물학적 운동과 같은 사건들을 지각하는 것에 특별한 감각을 가지고 있다고 주장해왔다. 하지만, 직접지각 접근법 연구자들은 말소리 지각이나 생물학적 운동은 어떠한 다른 사건들을 지각하는 것과 다르지 않다고 제안했다. 이 논문의 목적은 사건지각에 관한 운동이론과 직접지각 접근법의 관점에 대해 설명하고 운동이론을 비판함으로써 이 두 이론을 비교하는 것이다. 점차 발전하고 있는 로봇공학과의 융합에 있어서 이러한 인간의 기본적인 사건 지각 능력을 먼저 이해하는 것이 중요하다.

• 대한기관식도과학회지
• /
• 제15권2호
• /
• pp.36-41
• /
• 2009

Background : Controversy exists whether patients with esophageal carcinoma are best managed with classical Ivor Lewis esophagectomy(ILO) as combined thoracic and abdominal approach or transhiatal esophagectomy(THO). The THO approach is known to be superior with respect to operative time, morbidity and mortality, and length of stay, especially at poor pulmonary function patient, but may represent an inferior cancer operation due to inadequate mediastinal clearance compared with ILO. Accordingly, we estimated the THO role at esophageal cancer to compare each operative approach. Material and Method : From January 2002 to December 2007, we performed a retrospective review of all esophagectomies performed at Keimyung University Dongsan Medical Center; 36 underwent THO, and 11 underwent ILO. Result : There were all men and squamous cell carcinoma but 1 woman at ILO group, 2 women at THO group. There were no significant differences between THO and ILO with age, sex, location of tumor, mean tumor length. There were significant differences at preoperative pulmonary function test(In ILO group, average FEV1 is $2.65{\pm}0.6\;L/min$ and iIn THO group, average FEV1 is $2.07{\pm}0.7\;L/min$). The amount of blood transfusion, hospital stay, leak rates and respiratory complication, hospital mortality rate were not significantly different. Conclusion : There was no significant difference in the post-operative complication, hospital mortality rate, long-term survival of patients of both operative method. THO method had lower mobidity and mortality at poor pulmonary function patient than ILO method. Hence, THO is a valid alternative to ILO for patients with poor general condition or expected post-operative respiratory complication.

• 한국인구학
• /
• 제9권1호
• /
• pp.54-68
• /
• 1986

This study was designed to make a comparative analysis of fertility control policies in developing countries selected from Asia and Latin America. Considering the size and the density of population, the history of the fertility control policy, and the availability of references, eight countries were chosen among Asian developing countries that have adopted the fertility control as an official policy. All of nine countries in Latin America that have adopted family planning as an official policy were included in this study. An attempt was made to formulate an analytical framework to be used for a comparative analysis of fertility control policies. It can be represented by a continuum which consists of individual approaches and structural approaches to fertility control at both extremes. It represents fairly well the controversies between those who advocate family planning and those who advocate measures beyond family planning, but assumes that the two sides of the controversy form a continuum of approaches to fertility control. Various fertility control policies of each country were placed along this continuum and analyzed. The results of the analysis can be summarized as follows: (a) Those countries that have higher population pressure in terms of either the size of population or the population density tend to adopt fertility control policies earlier in time. (b) Those countries that have higher population pressure in terms of either the size of population or the population density tend to adopt more comprehensive measures along the continuum of fertility control policies. (c) Those countries that adopted more comprehensive measures along the continuum seem to have succeeded in reducing their level of fertility more effectively. (d) Developing countries in Asia tend to adopt more comprehensive measures to control fertility than those in Latin American countries. (e) The reduction of fertility in developing countries seems to be associated with both the fertility control policies and the level of socioeconomic development.

• 대한두경부종양학회지
• /
• 제18권1호
• /
• pp.71-75
• /
• 2002

Background and Objectives: The tracheotomy is one of the most essential surgical procedures performed in the intensive care unit (ICU). The tracheal stenosis, as a complication following endotracheal intubation or tracheotomy, has been the subject of considerable recent investigation. Many different methods have been developed to avoid the tracheal stenosis but there is still controversy about the tracheal incisions. We had performed tracheotomy using a vertical elliptical tracheal incision in the ICU to evaluate its efficiency and safety. Materials and Methods: 191 patients who underwent the tracheotomy in the ICU between 1995 and 2000 were reviewed retrospectively by chart records and interviews. Results: The complications were reported such as bleeding, infection, subcutaneous emphysema, pneumothorax, tracheoesophageal fistula and tracheal stenosis. The total numbers of complications were 35 cases (18.3%) and the tracheal stenosis was developed in 4 patients. The characteristics of tracheal stenosis are as follows. Conclusion: The vertical elliptical tracheal incision is the safe and reliable methods in ICU patients compared with other methods, but other factors are also important in preventing the complications.

• 대한두경부종양학회지
• /
• 제20권2호
• /
• pp.143-146
• /
• 2004

Background and Object: The role of fine needle aspiration cytology (FNAC) and frozen section (FS) in management of thyroid neoplasms continues to generate considerable controversy. We reviewed our current experience to determine the clinical utility of FNAC and FS in our surgical management and investigated reliability of FNAC and FS in planning the extent of thyroid resection. Material and Method: 212 patients who had operations for thyroid disease from May 1996 to November 2003 were included our retrospective study. FNAC was undertaken in 175 patients and FS was done in 148 patients. Result: The sensitivity and specificity of FNAC were 72.1% and 100%, respectively, and those of FS were 67.2% and 100%. The results of FNAC were benign (n=72) , malignancy (n=31), indeterminate (n=9), and nondiagnostic (n=63). The results of FS were benign (n=95), and malignancy (n=53). The 9 indeterminate cases on FNAC were benign (n=6) and malignancy (n=3) on final pathology, and benign (n=7) and malignancy (n=2) on FS. The false negative of FNAC were micro papillary carcinoma (n=6) and follicular carcinoma (n=6). The false negative of FS were micropapillary carcinoma (n=10) and follicular carcinoma (n=2). Conclusion: When results of FNAC are interpreted as indeterminate, FS is a valuable tool. FS is helpful in determining the extent of thyroidectomy when results of FNAC were follicular neoplasm. However we always concerned about micropapillary carcinoma and follicular carcinoma although FNAC and FS were benign.

• 보건행정학회지
• /
• 제14권3호
• /
• pp.97-121
• /
• 2004

Recently, human embryonic stem cell research raises exciting public expectation on medical possibilities as well as ethical debate. Embryo management has become an integral part of the management of infertility treatment, researches on embryo and human embryonic stem cells and so on. Britain has permitted the research on stem cells derived from human embryo which made the first nation to allow the cloning of human embryo for the stem cell research. However, new technologies such as the assisted reproductive technologies and human embryonic stem cell research continue to pose an increasing source of ethical dilemmas for physician, scientists, legislators, religious authorities and the general publics to deal with. None the less, the United Kingdom has adopted the most liberal policies regarding human embryo and human embryonic stem cell research. The implication of the British embryo management system are as follows: 1) the development of reproductive technologies and new stem cell research technologies continue to pose legal and ethical debates, since those involve several parties; 2) the UK has taken the legal and institutional approaches to cope with those serious issues; 3) the UK adopted most liberal policies regarding embryonic and human embryonic stem cell researches; 4) the British HFE Act is consistent with the existing Acts related to human embryo management and researches; 5) through amending the HFE Act to accomodate the changes of technologies, the UK try to minimize the legal and ethical burden on undertaking research regarding embryo. The debates about the researches on human embryo and human embryonic stem cells is likely to continue in the Korean society. Because of the controversy and competing ethical values, as well as the evolving technologies, so far no consensus exists in our society. It suggest that it is premature to bring closure by ruling out any particular approaches. Thus our society needs to make an efforts to find a basis which could resolve the societal controversies through enriching the societal conversation about the profound ethical issues regarding embryo management.

• 인터넷정보학회논문지
• /
• 제13권6호
• /
• pp.25-32
• /
• 2012

스마트폰에서 제공되는 방송서비스에 대해 지상파 혹은 케이블 수준의 규제를 적용해야 한다는 입장과 별도의 규제가 필요하지 않다는 입장이 대립하고 있다. 본 연구는 CJ 티빙서비스를 중심으로 스마트폰에서 제공되는 방송서비스에 대해 규제 방안을 제안하는 것이 목적이다. 연구를 위해 방송 및 콘텐츠 기업, 규제기관, 정책연구소, 컨설팅기업 간부급 14명으로 구성된 전문가 인터뷰를 실시했다. 인터뷰 분석 결과 스마트폰 방송서비스는 콘텐츠 형식으로 보면 방송의 형태를 띠고 있지만 당분간 규제가 필요 없다는 것이 공통적인 의견이다. 근거로 규제의 실효성이 낮고, 대부분의 콘텐츠가 이미 다른 플랫폼에서 검증 받았으며, 서비스의 사회적 영향력이 아직 미약하기 때문이다. 따라서 당분간 스마트폰 방송서비스는 인터넷과 같이 자율규제가 적합하며, 현행법에서 전기통신사업법의 부가통신사업으로 분류하는 것이 타당하다고 결론 내렸다.