Rupture of carotid artery pseudoaneurysm in the modern era of definitive chemoradiation for head and neck cancer: Two case reports

BACKGROUND Carotid blowout syndrome (CBS) is a rupture of the carotid artery and is mainly caused by radiation and resection of head and neck cancers or direct tumor invasion of the carotid artery wall. It is a life-threatening clinical situation. There is no established and effective mode of management of CBS. Furthermore, there is no established preceding sign or symptom; therefore, preventive efforts are not clinically meaningful. CASE SUMMARY We described two cases of CBS that occurred in patients with head and neck cancer after definitive chemoradiotherapy (CRT) using three-dimensional conformal intensity-modulated radiation therapy. Two men aged 61 and 56 years with locally advanced head and neck cancer were treated with definitive CRT. After completing CRT, both of them achieved complete remission. Subsequently, they had persistent severe pain in the oropharyngeal mucosal region and the irradiated neck despite the use of opioid analgesics and rehabilitation for relief of contracted skin. However, continuous follow-up imaging studies showed no evidence of cancer recurrence. Eleven to twelve months after completing CRT, the patients visited the emergency room complaining about massive oronasal bleeding. Angiograms showed rupture of carotid artery pseudoaneurysms on the irradiated side. Despite attempting to secure hemostasis with carotid arterial stent insertion and coil embolization, both patients died because of repeated bleeding from the pseudoaneurysms. CONCLUSION In patients with persistent pain in irradiated sites, clinicians should be suspicious of progressing or impending CBS, even in the three-dimensional conformal intensity-modulated radiation therapy era.ope

대한적십자사 직원을 중심으로

학위논문(석사) -- 서울대학교대학원 : 행정대학원 공기업정책학과, 2023. 8. 전영한.This study, which aim was to derive policy directions and prescriptive insights for the establishment of effective strategies for human resource management, endeavored to analyze the effect of public sector employees' perception of human resource management on their job attitudes. To this end, a research model was devised, with training and development, performance evaluation, job rotation, and promotion systems as the four independent variables, and job satisfaction and organizational commitment as the dependent variables. By conducting a survey among employees of the Korean Red Cross, the study thoroughly examined the significant relationships between the proposed model and the pertinent variables. The analysis results and implications can be summarized as follows. Firstly, the correlation analysis reveals that human resource management exhibits a positive effect on job satisfaction and organizational commitment. This demonstrates the considerable potential of utilizing human resource management systems as part of a comprehensive approach to enhance the overall performance of public sector organizations. Secondly, the regression analysis elucidates that among the constituent elements of human resource management, training and development as well as job rotation wield a noteworthy effect on job satisfaction and organizational commitment, surpassing the effect of other factors. This implies that through the active utilization of these two facets, organizations can yield superior outcomes not only in terms of job satisfaction and organizational commitment but also in the realm of overall performance. By providing practical and efficacious training programs that facilitate career development and expertise acquisition, coupled with a well-structured job rotation system that enables individuals to continually manifest their augmented capabilities, organizations can contribute not only to the satisfaction and commitment of their members but also to the advancement of organizational performance. Thirdly, the study discloses that performance evaluation and promotion systems, both integral components of human resource management, do not exert a significant effect on job satisfaction and organizational commitment. This observation suggests the existence of inherent skepticism or discontent among employees concerning the operation of these systems. Consequently, there arises a pressing need to refine the performance evaluation system, ensuring equitable evaluations grounded in individual efforts, job performance, and levels of responsibility, facilitated by comprehensive and methodical procedures. Likewise, regarding promotion, meticulous preparations encompassing fairness, transparency, and appropriateness within the system are imperative. However, it is important to acknowledge the limitations and future prospects of this study. Firstly, the study's purview is confined to employees of the Korean Red Cross, constraining the generalizability of its findings. Future research endeavors should endeavor to validate the postulates posited herein by incorporating data from diverse organizations, thereby enhancing the objectivity of the research. Secondly, the study cannot completely evade the issue of common method bias, arising from the interrelation between the measured variables due to the adoption of self-report surveys conducted simultaneously. Hence, future investigations should strive to surmount this limitation by employing multifaceted methodologies encompassing preliminary surveys, interviews, and diverse data collection techniques. Finally, while the study chiefly focuses on quantitative research relying on surveys to gauge organizational members' perceptions, it is indispensable to supplement this approach with qualitative research encompassing extensive examination of organizational documents, in-depth interviews with relevant stakeholders, and comprehensive analysis. This integration of qualitative research will engender a profound comprehension of the research problem at hand.본 연구는 인적자원관리에 대한 공기업 구성원의 인식이 직무태도에 미치는 영향을 분석, 효과적인 인적자원관리 전략을 수립하기 위한 정책방향 및 처방적 시사점을 도출하고자 하였다. 이를 위해 교육훈련, 근무평가, 보직관리, 승진제도 등의 네 가지 인적자원관리 요소를 독립변수로 하고 직무만족과 조직몰입을 종속변수로 하는 연구모형을 설정, 대한적십자사 직원들을 대상으로 한 설문조사 결과를 토대로 본 연구에서 설정한 모형과 이에 필요한 변수들 간의 유의미한 관계가 있는지를 구체적으로 분석하였다. 분석결과와 시사점을 요약하면 다음과 같다. 첫째, 상관관계 분석결과, 인적자원관리가 직무만족 및 조직몰입에 정(+)의 영향을 미치는 것으로 나타났는데, 이는 조직의 성과향상을 위한 공기업의 경영전략적 차원에서도 인적자원관리 제도를 활용할 유인이 충분하다는 것을 보여준다. 둘째, 회귀분석 결과 인적자원관리의 구성요소 중 교육훈련과 보직관리가 다른 요소들에 비해 직무만족 및 조직몰입에 유의미한 영향을 미치는 것으로 나타났는데, 이는 이 두 요소를 적극 활용할 경우 결국 조직의 성과 측면에서도 보다 향상된 결과를 얻을 수 있음을 시사한다. 즉, 구성원의 경력개발, 전문성 확보 등에 도움이 되는 실효성 있는 교육훈련을 제공하고, 교육훈련을 통해 향상된 자신의 역량을 지속적으로 발휘할 수 있도록 보직관리가 합리적으로 운영된다면 이는 구성원들의 직무만족 및 조직몰입은 물론 나아가 조직의 성과 향상에도 기여할 수 있을 것이다. 셋째, 인적자원관리의 요소 중 근무평가, 승진제도는 직무만족 및 조직몰입에 유의미한 영향을 주지 못하는 것으로 나타났는데, 이는 근무평가 및 승진제도의 운영에 대해 구성원들의 불신이나 불만 등이 잠재되어 있음을 보여준다. 따라서 종합적이고 체계적인 절차를 통해 개인의 노력, 업무성과, 책임수준 등에 따른 공정한 평가를 받을 수 있도록 근무평가 시스템을 개선할 필요가 있으며, 승진에 있어서는 적정성 및 공정성, 투명성 확보 등 제도의 합리적 운영과 관련한 준비를 철저히 할 필요가 있다. 다만, 본 연구는 다음과 같은 한계 및 향후과제를 가지고 있다. 첫째, 연구대상의 범위가 대한적십자사 직원으로 한정되어 있어 결과의 일반화에 한계가 있는 바, 향후 연구에서는 타 기관에 대한 자료를 토대로 본 연구에서 설정한 가설의 타당성 여부도 검증해본다면 연구의 객관성을 높일 수 있을 것이라 생각된다. 둘째, 본 연구는 동일한 시점에 자기보고식(self-report) 설문을 통해 두 개 이상의 변수를 측정했다는 점에서 측정변수 간 상관관계가 왜곡되어 나타나는 동일방법편의(common method bias)의 문제로부터 자유로울 수 없다는 한계가 있다. 따라서 향후 연구에서는 응답자의 자기보고식 설문뿐만 아니라 예비조사 및 면접조사 등의 방식을 통해 이를 극복할 필요가 있다. 마지막으로 본 연구는 조직구성원들의 인식조사를 통한 양적연구에 초점을 맞춘 관계로 향후 심도 있는 질적 연구의 보완이 필요하다. 즉, 조직에 대한 문서자료 수집 및 분석, 관계자의 심층 인터뷰 등을 통한 질적 연구도 함께 진행되면 연구문제에 대한 보다 심층적인 이해가 가능할 것이다.제1장 서론 1 제1절 연구의 배경 및 목적 1 1. 연구의 배경 1 2. 연구의 목적 및 필요성 3 제2절 연구의 대상 및 범위 4 제2장 이론적 논의와 선행연구 검토 5 제1절 직무만족 5 1. 직무만족의 개념 5 2. 직무만족의 중요성 6 제2절 조직몰입 7 1. 조직몰입의 개념 7 2. 조직몰입의 중요성 9 제3절 인적자원관리 10 1. 인적자원관리의 개념 10 2. 인적자원관리의 구성요소 11 3. 대한적십자사의 인적자원관리 14 제4절 선행연구 검토 및 가설설정 19 1. 인적자원관리와 직무만족 19 2. 인적자원관리와 조직몰입 20 제3장 연구설계 22 제1절 연구모형 22 제2절 변수의 정의 및 측정 23 1. 종속변수: 직무만족 23 2. 종속변수: 조직몰입 23 3. 독립변수: 인적자원관리 24 4. 통제변수 25 제3절 연구대상 및 자료수집 26 제4절 분석방법 26 제4장 연구결과 28 제1절 연구대상의 인구통계학적 특성 분석 28 제2절 측정도구의 타당성 및 신뢰도 분석 29 1. 독립변수의 타당성 및 신뢰도 분석 30 2. 종속변수의 타당성 및 신뢰도 분석 31 제3절 기술통계 분석 32 제4절 인구통계학적 특성에 따른 변수의 차이 검증 33 1. 연령에 따른 변수의 차이 검증 33 2. 성별에 따른 변수의 차이 검증 36 3. 소속기관에 따른 변수의 차이 검증 37 4. 계급에 따른 변수의 차이 검증 39 제5절 변수들 간의 상관관계 분석 43 제6절 가설검증 44 1. 인적자원관리에 대한 인식이 직무만족에 미치는 영향 44 2. 인적자원관리에 대한 인식이 조직몰입에 미치는 영향 45 제5장 결론 47 제1절 연구결과 요약 및 시사점 47 1. 연구결과 요약 47 2. 연구의 의의 및 시사점 50 제2절 연구의 한계 및 향후과제 51 참고문헌 54석

Complications of Cranioplasty Following Decompressive Craniectomy: Risk Factors of Complications and Comparison Between Autogenous and Artificial Bones

Objectives: Craniectomy is widely performed to lower the intracranial pressure in various conditions, such as traumatic brain injury, stroke, or brain swelling. Several complications can occur after craniectomy and cranioplasty, which significantly affect the prognosis of the patients after surgery. We studied the complications of craniectomy and cranioplasty and the factors affecting prognosis after the operation. Methods: Patients who underwent cranioplasty after craniectomy at Daejeon St. Mary's Hospital from 2015 to 2021 were included. We retrospectively reviewed their medical records and images. All patients were classified according to their sex, age, clinical grade, and diagnosis. Complications after craniectomy and cranioplasty were investigated for 1 year after surgery. The complications included postoperative hemorrhage, infection, hydrocephalus, and bone resorption. Results: This study included 104 patients. Complications after decompressive craniectomy were significantly frequent in patients with hypertension history (p=0.03). In contrast, complications of cranioplasty were significantly frequent in patients with history of diabetes mellitus, hepatic failure, or trauma (p=0.03, p<0.01, and p=0.01, respectively). Artificial bones were used more frequently than autologous bones in patients with trauma (p=0.03); however, there was no difference in the incidence of complications between them (p=0.64). Conclusion: Hypertension is a significant risk factor for decompressive craniectomy complications, especially rebleeding. Diabetes, hepatic failure, and trauma are significant risk factors for cranioplasty complications. There was no statistical difference in the incidence of complications between the use of autologous and artificial bones.ope

Role of Transarterial Embolization in the Treatment of Life-Threatening Hemorrhage in Patients With Maxillofacial Injury

Life-threatening hemorrhage following maxillofacial injury (MFI) is rare but can be fatal. Conventional measures for hemostasis including nasal packing, balloon tamponade, and surgical ligation of bleeding points may not be effective or efficient in patients at risk of hypovolemic shock. Advantages of transarterial embolization (TAE) include rapid identification of the bleeding focus and its access, direct obstruction of the culprit vessels, ability to control multiple bleeding sites, and no requirement of general anesthesia. The internal maxillary artery is the most frequently targeted vessel for embolization. Several studies have demonstrated that TAE was technically successful at rates between 79.4% and 100% and was associated with good clinical outcomes. However, major complications such as tongue necrosis or facial nerve palsy have rarely been reported (0%-7%), probably because of rich collaterals in the maxillofacial region, and failure to diagnose complications in patients who are severely disabled or died. Traditionally, Gelfoam and coils have been widely used as embolic materials. Polyvinyl alcohol particles and n-butyl-cyanoacrylate are also favored, and newer embolic materials, such as Onyx or precipitating hydrophobic injectable liquid, are available for use. Operators should be familiar with the distinctive characteristics of each embolic material. Early treatment with TAE for intractable hemorrhage may improve outcomes in patients with MFI, and further studies are necessary to develop a treatment algorithm to define when to initiate TAE in cases of severe oronasal hemorrhage following MFI.ope

RNF213 R4810K Variant in Suspected Unilateral Moyamoya Disease Predicts Contralateral Progression

Background Early-stage unilateral moyamoya disease (MMD) is difficult to discriminate from isolated intracranial atherosclerotic stenosis, and identification of contralateral progression may aid in the diagnosis of MMD. The RNF213 (ring finger protein 213) R4810K variant is a strong genetic susceptibility factor for MMD; however, the role of contralateral progression in unilateral MMD is unknown. Methods and Results Patients who had undergone RNF213 R4810K genotyping with suspected unilateral MMD between January 2017 and August 2021 from 2 tertiary university hospitals were retrospectively reviewed. We compared the clinical features and radiographic outcomes of patients with and without this variant. The risk factors of contralateral progression in patients with suspected unilateral MMD were evaluated. The RNF213 R4810K variant was observed in 72 of 123 patients with suspected unilateral MMD, all of which were heterozygous. The allele frequency of the R4810K variant was significantly higher in the suspected unilateral MMD group compared with the historical control group (29.3% versus 1.2%; P<0.0001). Family history of MMD was significantly more common in patients with the variant than in those without (17% versus 4%; P=0.003). Eleven of 72 patients with the variant developed contralateral progression, whereas only 1 of 51 patients without the variant developed contralateral progression during a median follow-up period of 28 months (log-rank test; P=0.03). The presence of the RNF213 R4810K variant significantly correlated with contralateral progression (adjusted odds ratio, 6.39 [95% CI, 1.11-36.63]; P=0.04). Conclusions Contralateral progression is more likely to occur in patients with suspected unilateral MMD with the RNF213 R4810K variant than in those without the variant. However, because our study used a small sample size, this finding should be carefully interpreted and requires further studies with more patients and longer follow-up periods.ope

Delays in Intracerebral Hemorrhage Management Is Associated with Hematoma Expansion and Worse Outcomes: Changes in COVID-19 Era

Purpose: The coronavirus disease 2019 (COVID-19) pandemic disrupted the emergency medical care system worldwide. We analyzed the changes in the management of intracerebral hemorrhage (ICH) and compared the pre-COVID-19 and COVID-19 eras. Materials and methods: From March to October of the COVID-19 era (2020), 83 consecutive patients with ICH were admitted to four comprehensive stroke centers. We retrospectively reviewed the data of patients and compared the treatment workflow metrics, treatment modalities, and clinical outcomes with the patients admitted during the same period of pre-COVID-19 era (2017-2019). Results: Three hundred thirty-eight patients (83 in COVID-19 era and 255 in pre-COVID-19 era) were included in this study. Symptom onset/detection-to-door time [COVID-19; 56.0 min (34.0-106.0), pre-COVID-19; 40.0 min (27.0-98.0), p=0.016] and median door to-intensive treatment time differed between the two groups [COVID-19; 349.0 min (177.0-560.0), pre-COVID-19; 184.0 min (134.0-271.0), p<0.001]. Hematoma expansion was detected more significantly in the COVID-19 era (39.8% vs. 22.1%, p=0.002). At 3-month follow-up, clinical outcomes of patients were worse in the COVID-19 era (Good modified Rankin Scale; 33.7% in COVID19, 46.7% in pre-COVID-19, p=0.039). Conclusion: During the COVID-19 era, delays in management of ICH was associated with hematoma expansion and worse outcomes.ope

속성 비집중과 후회 최소화 모형을 이용한 소비자의 이질적 의사 결정 구조 연구

학위논문(박사)--서울대학교 대학원 :공과대학 협동과정 기술경영·경제·정책전공,2019. 8. 이종수.Understanding consumer taste heterogeneity is always a crucial part of establishing marketing activities. The distributional approaches of consumer preferences have played an important role in statistical marketing applications. These statistical approaches have evolved in various ways, and this dissertation adds diversity to the field of consumer heterogeneity studies. This study proposes a series of models that capture consumer heterogeneous decision-making strategies as a perspective of consumer heuristic behavior by adopting a Bayesian stochastic search variable selection model. The proposed models in this dissertation are two fold. First, this study suggests a model for explaining consumers attribute non-attendance behavior with consumer characteristics. When consumers face complex decision-making situations, they are possibly attracted to or ignore one or more attributes while processing the information on offer, which cannot be explained with the usual random utility maximization model. Previous studies attempt to explain this attribute non-attendance behavior by questioning respondents directly or stochastically estimating a considered subset. However, these models do not explain the relationship between consumer non-attendance behavior and individual characteristics. This dissertation suggests a method for capturing respondents attribute non-attendance behavior based on their individual socio-demographic characteristics. Second, distinguishing agents decision-making strategies is also a critical issue for understanding consumer heterogeneity. Previous research suggests various alternative decision-making strategies and demonstrates consumer decision-making strategy with the latent class model or with comparison of model fit measures such as Akaike Information Criteria or Bayesian Information Criteria. These approaches may possibly classify consumer decision-making strategies but they do not fully identify individual heterogeneity for individual decision-making strategy. Among suggested alternative decision strategies, this dissertation focuses on random regret minimization, which is conceptually opposite to random utility maximization. This dissertation proposes a model for identifying individual decision-making behavior heterogeneity between random utility maximization and random regret minimization using the Bayesian stochastic search methods. The empirical analysis was conducted with three high-tech durable goods: a zero-energy house, a telecommunications bundle, and a vehicle choice behavior. High-tech durable goods were chosen for empirical analysis because high-tech durable goods have many attributes in comparison with other goods categories, and therefore, respondents face complex, uncertain decision-making situations while decision making process. The empirical results illustrated these attribute non-attendance and complex decision-making behaviors well. The suggested model in this dissertation has two main implications. First, from the perspective of the new product design process, manufacturers in the product planning stage should identify consumer consideration of product attributes. Next, setting up a marketing strategy based on segmentation, targeting, and positioning require classification of consumer characteristics based on consumer choices. The models suggested in this dissertation effectively organize consumer heterogeneity with reference to consumer socio-demographic traits.소비자의 이질성은 오랜 기간 동안 통계적 마케팅 선택모형 연구의 핵심적인 부분이었다. 소비자 이질성을 도출하기 위하여 다양한 확률적 접근방법들이(distributional approaches) 존재했고, 소비자 선호에 분포을 부여하여 소비자의 취향 이질성을 도출을 통해 소비자 이질성을 도출하는 방법론들이 제시되어 왔다. 본 연구는 소비자의 의사결정 전략을 확률적 변수 선택 모형 (Stochastic Search Variable Selection) 을 이용하여 포착하는 방법론을 제시한다. 제안하는 첫 번째 모형은 소비자의 대안 선택 시의 속성 비집중 (Attribute Non-Attendance) 행태를 소비자의 특성을 통하여 설명하는 모형이다. 소비자들은 복잡한 의사결정 상황에서 제공되는 모든 정보를 이용하지 못하고 의사결정 결과를 도출하게 된다. 선행 연구에서는 이러한 행태를 속성 비집중 이라는 용어로 설명하고 있고, 이에 대한 분석을 직접 응답자에게 묻거나, 고려대상이 되는 부분정보집합을 통계적으로 추론하는 방법론을 이용한다. 하지만 이러한 모형들은 개개인의 특성과 변수선택간의 관계를 소비자 특성과 연관 지어 설명하지 못한다. 본 연구에서 제안하고자 하는 모형은 소비자들의 attribute non-attendance 행태를 소비자의 특성과 연관 지어 설명할 수 있는 모형을 제시하고자 한다. 두 번째 모형은 소비자의 이질적인 의사결정구조를 효용 최대화(Random Utility Maximization)와 후회 최소화(Random Regret Minimization)의 관점에서 설명하는 모형이다. 기존 연구는 소비자의 대안적 휴리스틱 의사결정 모형을 결정하기 위하여 AIC, BIC와 같은 모형추정적합도를 비교를 하여 소비자의 대안적 휴리스틱 의사결정 모형을 설명했다. 본 연구는 소비자의 개별적 의사결정 행태의 이질성을 효용 최대화와 후회 최소화 관점에서 베이지안 변수탐색 모형을 이용하여 분석하는 방법론을 제시하고자 한다. 실증분석은 제로에너지 하우스 선택 상황, 방송통신 결합상품 선택 상황, 그리고 차량 구매 상황의 세 가지 첨단기술 내구재에 대한 소비자 선호 분석을 이용하였다. 소비재와는 달리 첨단 기술 내구재의 선택에 있어 소비자는 많은 정보를 처리해야 하고, 소비자의 특정 선호에 대한 확실한 개인 선호가 반영되기 때문이다. 또한 소비자는 내구재 선택에 있어 복잡한 의사결정 상황에 마주하고 있기 때문에 다양한 의사결정 구조 이질성을 가지고 있기 때문이다. 실증 분석 결과는 이러한 소비자의 복합적 의사결정 구조와 특정 대안에 대한 고려를 잘 보여주고 있다. 본 연구에서 제안한 모형은 두 가지 함의가 있다. 첫번째로 제품생산단계에서 제품기획단계의 생산자는 소비자의 제품 특성 고려에 대한 이질성을 도출하는 것을 필요로 한다. 두 번째로, 시장세분화, 표적시장 선점, 위상정립 마케팅 (STP Marketing) 측면에서 소비자들의 특성에 따라 확실한 시장 세분화를 필요로 한다. 본 연구에서 제안하는 모형은 이러한 문제들을 해결할 수 있는 모형이다.Chapter 1. Introduction 1 1.1 Research Background 1 1.2 Research Objectives 5 1.3 Research Outline 7 Chapter 2. Literature Review 9 2.1 Discrete Choice Models 9 2.1.1 Multinomial Logit Model 10 2.1.2 Consumer Heterogeneity in Choice Model 14 2.2 Stochastic Search Variable Selection Model 19 2.3 Decision Heuristics and Alternative Decision Rules 24 2.3.1 Decision Heuristics in a Choice Model 25 2.3.2 Attribute Processing Behavior 30 2.3.3 Random Regret Model 32 2.4 Limitations of Previous Research and Research Motivation 43 Chapter 3. Model 45 3.1 Methodological Framework 45 3.2 Heterogeneous Variable Selection Choice Model with Respondent Covariates 50 3.3 Heterogeneous Choice Model for Respondent Decision Heuristics Strategy 55 3.4 Model Validation 61 3.4.1 Bayesian Model Fitness Measure: WAIC and LOO 62 3.4.2 Model validation (I): Heterogeneous Variable Selection Choice Model with Respondent Covariates 64 3.4.3 Model validation (II): Heterogeneous Choice Model for Respondent Decision Heuristics Strategy 73 Chapter 4. Empirical Studies 82 4.1 The Study on Consumer Choice Behaviors in High-Tech Goods 1 – Zero Energy House (ZEH) 82 4.1.1 Introduction 82 4.1.2 Data Descriptions 86 4.1.3 Empirical Results 91 4.1.4 Discussions 112 4.2 The Study on Consumer Choice Behaviors in High-Tech Goods 2 – Telecommunication Bundling Choice (TBC) 114 4.2.1 Introduction 114 4.2.2 Data Descriptions 118 4.2.3 Empirical Results 122 4.2.4 Discussions 139 4.3 The Study on Consumer Choice Behaviors in High-Tech Goods 3 – Vehicle Choice (VC) 141 4.3.1 Introduction 141 4.3.2 Data Description 144 4.3.3 Empirical Results 147 4.3.4 Discussion 152 Chapter 5. Summary and Conclusion 154 5.1 Concluding Remarks and Contribution 154 5.2 Limitation and Future Studies 155 Bibliography 158 Appendix 1: Survey Questionnaires for ZEH 174 Appendix 2: Survey Questionnaires for TBC 180 Appendix 3: Survey Questionnaires for VC 184 Appendix 4: Structural Similarities of Dummy in RRM and RUM 189 Appendix 5: Full Empirical results of Empirical studies (Chapter 4) 193 Abstract (Korean) 208Docto

인천국제공항 3단계 건설 추진과정 중심으로

학위논문(석사)--서울대학교 대학원 :행정대학원 공기업정책학과,2019. 8. 최태현.우리나라 경제발전사는 국책사업의 발전과 그 궤를 같이 한다고 말 할 수 있을 정도로 관(官) 주도, 정부(政府) 주도의 성장전략으로 발전을 이룩했다. 그 중심에는 정부와 민간 사이의 중간자 역할을 수행했던 공기업의 역할과 함께 그러한 공기업이 추진한 국책사업이 있었기에 가능했다. 하지만 아쉽게도 국책사업이 국가경제 발전에 큰 역할을 수행했음에도 국민들이 국책사업을 바라보는 시선은 부정적인 경우가 많았다. 이는 성공보다는 실패한 사례가 집중적으로 언론에 부각되어 노출되었기 때문이며, 국책사업에 대한 국민들의 기대 또한 상당해 실패에 대한 실망감이 증폭되었기 때문이었다. 본 연구에서는 국민들의 기대감이 크고 전체 사회적 후생 증가에 영향을 미치는 국책사업이 성공하기 위해서는 어떠한 요인이 필요하며, 이를 실증적으로 분석하기 위한 사례로써 인천공항 3단계 건설 사업을 제시했다. 이를 위해 먼저 선행연구 분석을 통해 실패 및 성공사업을 고찰했으며, 이를 통해 국책사업 실패 및 성공요인을 도출했다. 먼저 선행연구를 통해 도출된 국책사업 실패요인은 환경적 요인(지대추구, 정치사업 등), 제도적 요인(형식적 견제장치 등), 행태적 요인(계획오류 등)으로 구분 할 수 있었으며, 국책사업 성공요인은 사업의 합목적성 확보(공익 부합여부)와 절차적 정당성 확보(객관적 검증제도, 협력적 거버넌스 등) 측면으로 구분 할 수 있었다. 이러한 실패 및 성공요인들을 인천공항 3단계 건설 사업에 적용하여 살펴본 결과 먼저 실패한 국책사업에서 나타났던 지대추구, 계획오류, 제도적 견제장치(예비타당성 조사 등) 미흡 등의 실패요소가 3단계 건설사업에서는 부정적으로 표출되지 않았으며, 사업으로 인한 사회적 후생증대, 목표에 의한 사업관리, 추진과정에서의 이해관계자 참여를 통한 다양한 검증절차 확립 등이 강점요인으로 나타났다. 또한 성공한 국책사업 에서 나타났던 사업의 합목적성과 절차적 정당성 확보 측면도 인천공항 3단계 건설 사업에는 긍정적으로 작용되었다. 사업의 합목적성 측면에서는 1990년 공항건설 당시부터 현재까지 보수, 진보 정권에 관계없이 사업이 지속되고 있는 점을 감안 할 때 사업 타당성이 확보되었다 볼 수 있었으며 현재까지 안정적 운영을 지속하여 정책적 효과성 측면에서도 좋은 평가를 받고 있는 것으로 나타났다. 절차적 정당성 확보 측면에서는 公社의 의사결정을 객관적인 외부시각 으로 검증 할 수 있는 제도적 장치가 여러 단계로 구축되어 있었고, 다양한 이해관계자 또한 사업단계 별로 충분한 피드백을 제공하고 있었다. 아울러 단순히 피드백에만 그치는 것이 아니라 실제 의견이 기본계획에 반영되어 수정 고시 되는 등의 의사결정 및 협력체계가 잘 구축되어 있었다. 앞서 설명한 성공한 국책사업의 두 가지 특징인 사업의 합목적성, 절차적 정당성 확보 이외에도 인천공항 3단계 건설 사업은 원활한 사업추진을 위한 긍정적인 요인들을 보유하고 있었다. 그것은 바로 학습-실행 메커니즘 구축인데, 과거에 추진되었던 건설 및 운영과정에서 발생한 미흡한 점을 끊임없이 학습하고 차기 사업에 반영시키는 실행 프로세스가 존재했으며 실제 터미널 시설설계 및 운영에 동 사항이 반영되어 서비스 개선에 활용되었다. 본 연구의 정책적 함의는 크게 3가지로 제시될 수 있다. 국책사업이 성공하기 위해서는 왜 사업을 해야 하는지, 사업을 통해 국민편익이 얼마나 증대되는지를 판단하는 사업의 합목적성 확보, 이러한 사업의 합목적성을 강화하고 외부적 시각으로 사업을 평가하고 바라보는 절차적 정당성 확보 그리고 과거 동일 혹은 유사 사업에 대한 충분한 학습을 통해 실패의 전철을 밟지 않는 학습-실행 메커니즘 구축이 바로 그 것이다. 마지막으로 사업의 합목적성은 시대적 가치에 따라 변화는 동태적 개념이므로, 합목적성도 국책사업 성공에 중요한 요인이지만 향후 절차적 정당성 측면에서 좀 더 깊게 사업을 고찰한다면 협력적 거버넌스가 확대되는 시대 흐름에 부합되는 좀 더 의미 있는 연구결과를 도출할 수 있을 것이다.Korea's economic development history has achieved development through government-led growth strategies to the extent that it can be said that it is in line with the development of national project. At its core was the role of public corporations, which played the middleman role between the government and the private sector, as well as national project promoted by such state-run companies. Unfortunately, however, the public has often taken a negative view of national project, even though they played a big role in the development of the national economy. This was not because of success, but because the media was heavily exposed to the failed cases, and the public's expectations for national project were considerable, leading to mounting disappointment over the failure. In this study, the third stage construction project at Incheon International Airport was proposed as an example of how the government needs to succeed in a national project that has high public expectations and affects the overall increase in social wellbeing. To this end, the government first considered failure and success projects through prior research analysis, and derived the factors for failure and success of national project. First, the failure factors of the national project, which were derived through prior research, could be divided into environmental factors (e.g., zone pursuit, political projects,etc.) and institutional factors (type checking devices, etc.) and behavioral factors (planning errors, etc.) while the success factors of the national project could be distinguished by securing the project's relevance (objective verification system, cooperative governance, etc.). The application of these failures and success factors to the third stage construction project at Incheon International Airport revealed that the failure factors, such as rent seeking, planning fallacy, the lack of institutional check-up system(such as a preliminary feasibility study), were not negatively expressed in the third stage construction project, and the establishment of various verification procedures through the social welfare increase due to the project, management of the project by the goal, and participation of stakeholders in the project. Also, the feasibility and procedural justification aspects of the project, which were shown in the successful state project, were positively influenced by the Incheon International Airport's third stage construction project. In terms of project relevance, it has been shown that project feasibility has been secured considering that the project has continued to be carried out regardless of the conservative and liberal administrations since the airport was built in 1990, and that the project has been well received in terms of policy effectiveness as it has continued its stable operation to date. In terms of securing procedural legitimacy, institutional devices were built in several stages to verify Incheon International Airport corporation's decision with objective external vision, and various stakeholders were also providing sufficient feedback at each stage of the project. In addition, the decision-making and cooperative system was well established, with actual opinions reflected in the basic plan and revised. In addition to securing the project's relevance and procedural legitimacy, the two characteristics of the successful national project described earlier, the Incheon International Airport's third stage construction project had positive factors for the smooth promotion of the project. It was the establishment of a learning-execution mechanism, in which a continuous learning process existed to reflect the deficiencies of the construction and operation processes that had been implemented in the past and the implementation process was reflected in the actual design and operation of the terminal facilities and was utilized for the improvement of the actual service. The policy implications of this study can be presented in three main ways. They include securing the project's relevance in determining why the national project should be successful, how much people's benefit is increased through the project, securing procedural justification for enhancing the project's relevance and assessing and viewing the project from an external perspective, and establishing a learning-practice mechanism that does not follow in the footsteps of failure through sufficient learning of the same or similar projects in the past. Finally, since the relevance of the project is dynamic, it is important for the success of the national project, but further consideration of the project in terms of procedural justification in the future may lead to more meaningful research that conforms to the trend of the era in which cooperative governance is expanded.제 1 장 서 론 ···························································1 제 1 절 연구목적 및 필요성 ··············································1 제 2 절 연구대상 및 방법 ···················································7 제 2 장 이론적 배경 및 선행연구 검토 ············· 8 제 1 절 이론적 배경 ·····························································8 1. 환경적 영향요인 관련 이론 ···············································8 2. 제도적 영향요인 관련 이론 ···············································10 3. 행태적 영향요인 관련 이론 ···············································12 제 2 절 선행연구 분석 ·························································14 1. 국책사업 실패사례 ·······························································14 2. 국책사업 성공사례 ·······························································23 3. 기존 선행연구와 차별성 ·····················································37 제 3 장 연구의 설계 ·················································38 제 1 절 선행연구 통한 사업실패 및 성공요인 도출 ··· 38 제 2 절 연구모형 ···································································44 제 4 장 인천공항 건설사업 개관 ·························· 47 제 1 절 인천공항 태동 ························································· 47 제 2 절 1단계 공항건설 ······················································· 53 제 3 절 2단계 공항건설 ······················································· 56 제 4 절 3단계 공항건설 ······················································· 60 1. 사업 추진배경 및 필요성··················································· 60 2. 사업개요 및 추진내용 ························································· 63 제 5 장 인천공항 3단계 건설 Case Study ······· 67 제 1 절 연구모형을 통한 전체 사업프레임 분석 ······· 67 제 2 절 실패요인 관점에서 바라본 인천공항 ············· 73 제 3 절 성공요인 관점에서 바라본 인천공항 ············· 83 제 4 절 사업에 긍정적 영향을 끼친 추가요인 ··········· 97 제 6 장 결 론 ······························································ 104 제 1 절 연구요약 ································································· 104 제 2 절 정책적 함의 ··························································· 107 제 3 절 연구의 한계 ··························································· 109 참고문헌 ········································································ 110 Abstract ········································································ 115Maste

Human aminoacyl-tRNA synthetase의 결합인자인 p43의 다양한 생물활성과 의약학적 응용

Thesis(doctoral)--서울대학교 대학원 :제약학과 미생물약품화학전공,2005.Docto

프론트홀이 제한된 클라우드 기지국에서의 거대 다중안테나 기법

학위논문 (박사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2015. 8. 박세웅.To satisfy the ever-increasing capacity demand and quality of service (QoS) requirements of users, massive MIMO (multiple-input multipleoutput) has been attracted as a promising technique in next generation wireless networks. Employing large-scale antennas, however, at remote radio heads (RRHs) generates heavy traffic to be carried through fronthaul links in cloud radio access networks (C-RANs). In this dissertation, we investigate C-RAN architecture, fronthauling methods, and multiple-input multiple-output (MIMO) transmission strategies to overcome explosive fronthaul traffic while maintaining the potential of C-RAN and massive MIMO to the fullest. Firstly, we proposed a partially-centralized C-RAN (PC-RAN) architecture where precoder, data symbol, and channel state information (CSI) are separately transported in fronthaul links. With the proposed PC-RAN, fronthaul traffic can be remarkably reduced with no or marginal performance degradation, compared with the conventional fully-centralized C-RAN (FC-RAN). Secondly, we mathematically evaluated the performance of zero-forcing based large-scale MIMO. We derive wireless performance and fronthaul traffic taking account of cooperative processing among RRHs in C-RAN environments. Through extensive simulations, we confirmed the accuracy of our analytical model and provided intuition on trade-off between wireless performance and fronthaul traffic volume. Thirdly, we investigated a joint beamforming and resource allocation problem of a single RRH for a constrained fronthaul capacity. We provide a heuristic algorithm to decide beamforming configuration and bandwidth allocation for each beamforming technique. The simulation results show that the proposed algorithm further improves the wireless sum-rates and achieves near optimal performance in our proposed partially-centralized C-RANs. Lastly, we investigated the performance of ZF and MRT with two fronthauling methods in fronthaul-constrained C-RANs. We provide an algorithm to decide the optimal fronthauling method and beamforming strategy to maximize the wireless sum-rate under a limited capacity of fronthaul link. Numerical results confirm that the sumrate gain is greater when both fronthauling solutions are available.Contents 1 Introduction 1 1.1 Motivation and Background . . . . . . . . . . . . . . . 1 1.2 Contributions and Outline . . . . . . . . . . . . . . . . 5 2 A Partially-centralized C-RAN Architecture for Mas- sive MIMO 7 2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . 7 2.2 System Architecture and Challenging Issues . . . . . 10 2.2.1 Heterogeneous Cloud Radio Access Network with Large-scale Antennas . . . . . . . . . . . . . . . 10 2.2.2 Challenging Issues in Massive MIMO on H-CRAN 12 2.3 Fully Centralized C-RAN and Fronthaul Transport Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.3.1 Radio over Fiber . . . . . . . . . . . . . . . . . 16 2.3.2 Digitized IQ Data Transport . . . . . . . . . . 17 2.4 Partially Centralized C-RAN for Massive MIMO . . . 19 2.4.1 Basic Concept . . . . . . . . . . . . . . . . . . 21 2.4.2 Centralized and Distributed Precodings . . . . 23 2.4.3 CSI Estimation and Report . . . . . . . . . . . 27 2.4.4 Operation of Centralized/Distributed Precoding 28 2.4.5 Performance Evaluation & Discussion . . . . . 31 2.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . 36 3 Performance Analysis of Large-scaleMIMO in C-RANs 37 3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . 37 3.2 System Model . . . . . . . . . . . . . . . . . . . . . . 41 3.2.1 Deployment and Operation Scenario . . . . . . 41 3.2.2 Interference and Desired Signal . . . . . . . . . 42 3.3 Analytical Model using Stochastic Geometry . . . . . 43 3.3.1 User Distribution . . . . . . . . . . . . . . . . . 44 3.3.2 Interference . . . . . . . . . . . . . . . . . . . 48 3.3.3 Desired Signal . . . . . . . . . . . . . . . . . . 50 3.3.4 Signal to Interference Ratio . . . . . . . . . . . 51 3.3.5 Fronthaul Traffic Analysis . . . . . . . . . . . . 53 3.4 Simulations . . . . . . . . . . . . . . . . . . . . . . . . 54 3.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . 57 4 Large-scale ZF and MRT Beamforming in Partially-centralized C-RANs with Limited Fronthaul Capacity 59 4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . 59 4.2 Motivation and Proposed Architecture . . . . . . . . . 64 4.2.1 Cloud Radio Access Networks . . . . . . . . . . 64 4.2.2 Partially-centralized C-RAN for Massive MIMO 65 4.3 System Model . . . . . . . . . . . . . . . . . . . . . . . 68 4.3.1 Massive MIMO Scenario . . . . . . . . . . . . . 68 4.3.2 Required Transmission Rate for MIMO Operation 70 4.4 Operation Strategy . . . . . . . . . . . . . . . . . . . . 73 4.4.1 Problem Formulation . . . . . . . . . . . . . . 74 4.4.2 Heuristic Algorithm : Beamforming Configuration and Subchannel Allocation . . . . . . . . . 76 4.5 Performance Evaluation and Discussion . . . . . . . . 78 4.5.1 Scenario . . . . . . . . . . . . . . . . . . . . . . 78 4.5.2 Optimality and Performance Ratio . . . . . . . 79 4.5.3 Simulation Results . . . . . . . . . . . . . . . . 82 4.5.4 Discussion . . . . . . . . . . . . . . . . . . . . . 87 4.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . 89 5 Before/After PrecodedMassiveMIMO in C-RANs with Fronthaul Capacity Limitation 91 5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . 91 5.2 Notation . . . . . . . . . . . . . . . . . . . . . . . . . . 96 5.3 System model . . . . . . . . . . . . . . . . . . . . . . . 98 5.3.1 Channel Estimation and Multi-user Beamforming 98Docto