1,721,013 research outputs found
- Frequency Sharing of Wi-Fi/LTE-U -
Get PDF학위논문 (석사) -- 서울대학교 대학원 : 공과대학 협동과정 기술경영·경제·정책전공, 2020. 8. Jorn Altmann .5세대(5G) 이동통신 확산을 위하여 정부는 '비면허 5G' 주파수 대역인 6GHz 대역폭에 최대 1.2㎓ 폭을 공급할 예정이다. 4차 산업에 대응하여 기업이 스마트 공장에 적합한 맞춤형 5G망을 구축하기 위한 목적이다. 과학기술정보통신부(MSIT)는 6㎓ 대역 대상으로 비면허 주파수 대역의 5G 연구반을 가동, 주파수 분배 방안 수립과 기술 기준 제정에 착수한 것으로 확인됐다. 비면허 5G(NR-U)는 정부가 개방한 비면허 주파수 대역에 5G 코어망과 기지국 등 표준 기술을 적용해 초저지연초고속 성능을 구현하는 기술로, 6월 국제민간표준화기구(3GPP) 상용화를 앞두고 있다. 그러나 5/6GHz 대역의 주파수는 와이파이와 LTE-LAA가 공존하게 될 영역으로 이해관계자들의 주장이 엇갈리고 있다. LBT (Listen-Before-Talk)는 비면허 주파수를 공유하는 방법으로 기술적/행정적 방안으로, 채널을 분석하여 데이터를 전송하기 가장 적절한 주파수대역을 선출하는 방법중에 하나이다. 이 대역을 선출하기 위한 기술 방법은 CCA (Clear Channel Assessment)라고 한다. 이 기술은 LTE 통신사업자들이 개발한 기술로 구체화된 기술표준을 요구하고 있다. 하지만, 이 기술을 와이파이 사업자 입장에서는 이 기술의 실제 실용가능 여부에 대해 의구심을 갖고 있다. 그 이유는 해당 기술이 지나치게 LTE 통신사업자들에게 유리하게 개발된 기술이라는 논쟁이 있기 때문이다. 이에 통신기술정책 결정자는 양측이 공존할 수 있는 법 제정방안을 강구해야 하며, 이 논문에서는 기존 와이파이 사용자들을 보호하며 통신 사업자들 역시 주파수를 공유할 수 있는 제도 정책의 방법을 정책자 입장에서 연구해보자 한다. 비면허 주파수를 개방하게 되었을 때 채널 사용자 비율과 라이선스 배부 비율 사이의 효율성에 대해 연구하였다. 그리고, 사용 가능한 채널을 비교하는 방법을 기존연구를 통해 비교하고 새로운 모델을 개발 했다. 또 기술 표준으로 이미 제정 된 노이즈 한계치가 실제 공유가 됐을 때 어떤식으로 작용되는 지를 알아보기 위해 시뮬레이션 분석을 통해 예측해 보았다.A spectrum-sharing policy is yet to be established for unlicensed bands. There are several controversies related to providing 5-GHz (5G) band service with the coexistence of Wi-Fi and LTE–LAA (License Assisted Access). LTE–LAA is a technical and political scheme for sharing spectrum bands. Using this technique, the channel can be evaluated, and a proper channel can be selected before data transmission. This mechanism is called listen before talk (LBT), and the channel selection procedure is called clear channel assessment (CCA). LTE service providers suggest standardizing this technology using an unlicensed band. However, existing Wi-Fi users are skeptical about the sharing process. In this paper, we describe proper spectrum-sharing mechanisms based on policy-based channel selection algorithms. Based on the results, proper regulation of the 5G LTE-U is required to avoid conflicts among service providers. This work uses a policy-based mechanism to understand the role of the government in managing these bands. The main idea is that stricter sharing-policy regulations and higher thresholds must be implemented to protect the rights of existing users.1. Introduction 1
1.1 Research Background 1
1.2 Problem Description 2
1.2.1 Controversies on Wi-Fi and LTE-U Coexistence 2
1.3 Research Question 4
1.3.1. Fairness and Efficiency of Sharing Policy 4
1.3.2. Evaluation and Simulation of Sharing Technology 5
1.4 Contribution 5
2. Literature Review 6
2.1 Spectrum-Sharing Policy 6
2.1.2 Case of South Korea 8
2.2 Spectrum-Sharing Technologies 10
2.2.1 Licensed Assisted Access (LAA) 11
2.2.2 Listen Before Talk (LBT) 13
2.2.2.1 Qualcomm Evaluation 13
2.2.2.2 3GPP Evaluation 16
2.3 Comparison with Previous Work 17
3. Modeling 20
3.1 General Assumption 22
3.2 Flow Chart 23
3.2.1 License Type Evaluation (Guard Interval Evaluation) 23
3.2.2 Energy Detection Evaluation 26
4. Simulation 29
4.1 Parameter setting 29
4.2 Simulation Result 31
5. Conclusion 36
5.1 Overall Implication 36
5.2 Limitation 37
5.3 Further study 37
Appendix 39
Bibliography 47
Abstract (Korean) 50Maste
A Social Network System for Analyzing Publication Activities of Researchers
No full textSocial networks play an increasingly important role in knowledge management, information retrieval, and collaboration. In order to leverage the full potential of social networks, social networks need to be supported through technical systems. Within this paper, we introduce such a technical system. It is called AcaSoNet. It is a system for identifying and managing social networks of researchers. In particular, AcaSoNet employs a combination of techniques to extract co-author relationships between researchers and to detect groups of persons with similar interest. Past systems have used either search engines to extract information about social networks from the Web (Web mining) or have required people¡¯s effort to enter their relationships to others into the system (as being done by most social network services). AcaSoNet, instead, uses a combination of these two types, thereby achieving data reliability and scalability. It extracts and collects data of researchers from the Web but allows researchers to modify the data. In the current version, our system can identify the social network based on publication lists and evaluate the publication activities of users within an academic community.Social network systems, academic community, co-author relationship, publication analysis, productivity analysis, knowledge sharing, knowledge transfer, Web mining, performance analysis, and social network analysis.
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
주요 융합 기술과 R&D 주체의 동적 네트워크 분석을 통한 ICT-자동차 제조업 융합에 관한 연구
Get PDF학위논문 (석사)-- 서울대학교 대학원 : 기술경영·경제·정책전공, 2017. 2. Jorn Altmann.This paper aims to identify convergence between automobile manufacturing and ICT sectors in Koreas national R&D network. Although several studies have analyzed the technology convergence or cooperative alliances in R&D networks, network analysis specifically on Auto manufacturing-ICT convergence that contributes to identifying both important convergence technology and R&D actors over time is lacking. In an effort to bridge this gap, this study employs network analysis of patent information of the auto manufacturing and ICT sectors from 2008 to 2014. The dynamic changes of the two key subjects of interest, important convergence technology and R&D actors, are then examined together in groups of important technology identified as hubs, cores, and bridges. The analysis results are expected to help identify priority areas and actors for R&D policies on auto manufacturing-ICT convergence as part of an effort to prepare for the ICT-driven manufacturing paradigm shift taking place today.Chapter 1. Introduction 1
1.1 Background 1
1.2 Research Objective 2
1.3 Overview 2
Chapter 2. Literature Review 3
2.1 Literature Review on R&D Networks 3
2.2 Problem Description 3
2.3 Research Questions 3
Chapter 3. Model 5
3.1 Analysis Process 5
3.2 Collection of Patent Data 5
3.3 Extraction and Classification of Patent IPC Codes 6
3.4 Formulation and Analysis of the IPC Co-occurrence Network 7
Chapter 4. Data 11
4.1 Data 11
Chapter 5. Analysis results 12
5.1 Change in the Measures of the Entire Cumulative IPC Co-occurrence Network 12
5.2 Change of Important Technology and R&D Actors over Time 15
5.2.1 Important ICT-related Technology 15
5.2.2 Important R&D Actors over Time 17
Chapter 6. Conclusion 20
6.1 Key Findings and Implications 20
6.2 Contribution 21
6.3 Limitations and Future Study 21
Bibliography 23
Appendix 1: Full Version of Table 6 on Network Positions of ICT-related IPCs in Auto Manufacturing including the Column "Periphery" (2008-2014) 25
Appendix 2: Change in the Total Number of Applied Patents by Combination of R&D Actors for ICT-related hub IPCs 27
Abstract (Korean) 30Maste
Consumers Willingness-to-pay for Security in E-commerce Payment Systems
Get PDF학위논문 (석사)-- 서울대학교 대학원 : 협동과정 기술경영경제정책전공, 2015. 7. Jorn Altmann.For accessing Internet shopping mall websites, online banking websites, and e-government websites, due to the Digital Signature Act of Korea, which was in force from 1999 to March 2015, South Korean consumers had to use a two-sided digital authentication mechanism (TSDAM) to prove their identities. Although the use of TSDAM in e-commerce is not required anymore, today, lots of e-commerce payment systems are still based on TSDAM. This raises the question how consumers perceive this security feature of e-commerce systems. To answer this question, we estimated consumers willingness-to-pay for different e-commerce attributes by using a conjoint analysis method. In detail, we investigated the stated preferences of individuals with respect to ease-of-use, compatibility, TSDAM, and additional security mechanisms (e.g., confidentiality, none-replay) of e-commerce payment services. The results show that only compatibility and additional security mechanisms are significant attributes for Korean Internet users. Korean consumers are not willing to pay for TSDAM despite its widespread use. The implications of these research results are twofold: First, poorly designed e-commerce security regulation frameworks can be perceived by consumers as insufficient, consequently limiting the success of e-commerce. Second, consumers are willing to pay for security mechanisms, if the security mechanism (e.g., confidentiality) helps protecting their e-commerce transactions.Table of contents
Abstract i
Table of contents iv
List of figures and tables vii
Chapter 1. Introduction 1
Chapter 2. State-of-the-art
2.1. E-Commerce Payment Systems 8
2.2. Pricing of Payment Services 9
2.3. Two-sided Digital Authentication System 11
2.4. Acceptance of E-Commerce Payment Systems 13
Chapter 3. Proposed Acceptance Model for E-Commerce Payment Systems
3.1. Experiment Design 17
3.1.1. TSDAM 18
3.1.2. Compatibility 19
3.1.3. Ease of Use 20
3.1.4. Security 21
3.1.5. Price 23
3.2. Methodology 24
Chapter 4. Analysis
4.1. Data Collection 28
4.1.1. Collection Process 28
4.1.2. Descriptive Statistics 29
4.2. Model Estimation 30
4.3. WTP Analysis 33
Chapter 5. Discussion and Implications
5.1. Discussion 34
5.2. Implications 37
Chapter 6. Conclusion
6.1. Summary 41
6.2. Limitations 43
References 44
Appendix: 54Maste
죄수의 딜레마 게임 측면에서의 개인의 경제행동과 사회 상호작용 분석: 시뮬레이션 방법을 이용하여
Get PDF학위논문 (석사)-- 서울대학교 대학원 : 기술경영·경제·정책전공, 2017. 2. Jorn Altmann.개인의 의사 결정 과정에 대한 전통적인 미시 경제 개념에서 시작하여 선택은 합리적인 행동과 효용 극대화의 개념에 기초하여 이루어진다. 그러나 행동 경제학 분야의 여러 연구에서 의사 결정 과정을 더 잘 이해하고 대표하기 위해이 전통적인 모델과 보완 이론에 의문을 제기했다.
이 연구는 의사 결정 과정에 존재하는 제한된 합리성과 관련된 행동 경제학의 진술을 분석하고 개인적 관점에서 집단적 차원으로 바라보고자, 다중 에이전트 기반 모델링과 같은 전산 경제학 기법, 사회 및 경제 네트워크, 죄수의 딜레마 게임의 수정 버전을 사용한 모델을 제시한다. 소셜 네트워크 시뮬레이션에서 에이전트 기반 모델은 게임 성능 및 결과에 관한 특수성을 연구 할 목적으로 개인의 경제적 행동과 사회적 상호 작용을 모방 할 수있게 한다.
본 연구의 결과는 인공 환경에서 개인의 비합리적 행동을 재창조하고 사회 시나리오에서의 합리적 행동과 비교할 수 있는 가증성을 제시한다. 연구 결과에 따르면 게임의 결과는 임계점, 전환 시간 및 지배 전략의 전환과 관련하여 합리적이고 비합리적인 행동의 차이가 있음을 시사한다. 이 연구의 향후 응용 방안은 정책 설계를 개선하고 사회에 미치는 영향 분석이다.Starting from the traditional microeconomic concept of the individuals decision process, choices are made based on the concepts of rational behavior and utility maximizationhowever, several studies from the field of behavioral economics have questioned this traditional model and proposed complementary theories in order to understand and represent the decision-making process better.
To analyze the statements of behavioral economics related to bounded rationality present in the decision-making process and looking from individual to collective levels, this research offers a model using the techniques of computational economics, such as multi-agent based modeling, and the concepts of social and economic networks. The proposed model recreates a scenario of the game on networks using a modified version of the Prisoners Dilemma game. The agent-based model in a social network simulation allows us to emulate individuals economic behavior and social interactions with the purpose of studying particularities concerning game performance and outcomes.
The results of the present research demonstrate that in an artificial environment, it is possible to recreate the irrational behavior of individuals and compare it with rational behavior in a social scenario. The findings show that the outcome of the game has differences between rational and irrational behavior in terms of threshold point, conversion time, and transition of the dominant strategy. The application of this research can improve the design of policies and analyze their impact on the society.Chapter 1. Introduction 1
1.1. Motivation and Background 1
1.2. Problem Description 2
1.3. Research Questions 3
1.4. Objectives 4
1.5. Methodology 4
1.6. Contributions 5
1.7. Overview of the Rest of the Paper 6
Chapter 2. Fundamentals of the Model 8
2.1. Perspectives of Economics 8
2.2. Economic Representations 9
2.2.1. Preferences, Choices, and Utility 9
2.2.2. Uncertainty and Risk in Economic Behavior 11
2.2.3. Expected Utility 12
2.2.4. Prospect Theory 13
2.3. Networks 17
2.4. Game Theory 19
2.4.1. Definition of Games in Normal Form 19
2.4.2. Games Classification 20
2.4.3. Nash Equilibrium and Pareto Optimal 22
2.4.4. Pure and Mixed Strategy 23
2.4.5. Repeated Games 24
2.4.6. The Prisoners Dilemma Game 25
2.4.7. Games on Networks 28
2.5. Agent-Based Computational Economics 29
2.5.1. Concept, Characteristics, and Principles 29
2.5.2. Interactions, Emergent Patterns and Adaptive Behaviors 31
2.6. Literature Review of Games on Networks and the Prisoners Dilemma Game 32
Chapter 3. Model Description 35
3.1. Game Model Framework 35
3.1.1. Decision Process 35
3.1.2. Interaction Process 37
3.1.3. Game on Network Process 38
3.2. Example Analysis 45
Chapter 4. Simulation and Results 49
4.1. Agent-Based Model Description 49
4.1.1. Purpose 49
4.1.2. Entities, State Variables, and Scales 50
4.1.3. Process Overview and Scheduling 51
4.1.4. Design Concepts 51
4.1.5. Initialization 53
4.1.6. Input Data 54
4.1.7. Submodels 54
4.2. Expected Utility and Prospect Theory Outcome Analysis 56
4.3. Network Structures Performance Analysis 59
4.4. Model Application 65
Chapter 5. Conclusions and Recommendations 67
5.1. Conclusions 67
5.2. Recommendations 69
5.3. Model Limitations and Future Research 70
References 71
Appendix A 75
초록 82Maste
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
잠재적 소비자의 관점으로 자율주행자동차에 대한 혁신저항 분석 : 잠재적인 리스크와 소비자 태도가 미치는 영향을 중심으로
Get PDF학위논문 (석사)-- 서울대학교 대학원 공과대학 협동과정 기술경영·경제·정책전공, 2017. 8. Jorn Altmann.Because of developed technology in artificial intelligence (AI), robots can replace human work and reduce time and resources. One of the main technological applications of AI is in autonomous (self-driving) cars which are expected to be driven by robots and AI systems instead of human drivers. The National Highway Traffic Safety Administration (NHTSA) have presented five degrees of autonomous car level employing Advanced Driver Assistance Systems (ADASs). From non-autonomous to fully autonomous cars, the functions carried out by an ADAS are added sequentially. Currently, vehicles in level 2, which includes two primary function junctions, are available on the automobile industry market, so the need for research into self-driving cars is obvious to investigate the gap between the market situation and customer perspective toward autonomous cars.
In previous literature, a technology acceptance model (TAM) has only emphasized technological aspects and their effect on customers positive adoption, and innovation has always been seen as a positive aspect. However, the concept of innovation resistance has given new insight into accepting innovation in the psychological area. Therefore, in this paper, the focus is on innovation resistance and its factors, which are customer attitude and perceived resistance, with regard to different levels of autonomy based on Rams (1987) innovation model, but with extended variables of perceived risk and customer attitude.
The data were collected from 335 samples from online surveys, the participants of which ranged in age from 20 to 60the data were distributed uniformly by age and gender groups. The target participants for the survey were individuals who were willing to buy a car within 10 years and had a drivers license. The model was analyzed with a multiple regression model using dependent variables of innovation resistance and intention to adopt. Potential risks were shown to have a positive impact whereas customer attitudes were shown to have a negative impact on innovation resistance. In addition, we found that customer attitude and potential risk factors had different effects on innovation resistance and innovation acceptance. As a result, while the risk of social and physical risks influenced innovation resistance, consumer attitudes such as economic risk, pleasure, and rigidity were more influential on the intention to adopt.Chapter 1. Introduction 1
1.1 Introduction 1
1.2 Problem Description 1
1.3 Research Objective 3
Chapter 2. Literature Review 4
2.1 Self-Driving Car 4
2.1.1 Definitions of Self-Driving Car 4
2.1.2 Five levels of Self-driving car 5
2.1.3 Current state of Self-driving car in a market 8
2.1.4 Challenges of Self-driving car 9
2.2 Innovation Resistance 11
2.2.1 Two different views for innovation 11
2.2.2 Factors of innovation resistance 14
2.2.3 The relationship between innovation resistance and intention to adoption 17
2.2.4 Highlights gaps from previous research 19
Chapter 3. Methodology 19
3.1 Research Model 19
3.2 Variables 21
3.2.1 Dependent Variable 22
3.2.2 Explanatory Variables 23
3.3 Survey Procedure and Sampling 29
3.4 Data Distribution 31
3.5 Data Quality 37
3.6 Methodology 40
3.6.1 Multiple regression model 40
Chapter 4. Analysis Result 43
4.1 Multiple regression Model 43
4.1.1 Model 1: Innovation resistance 43
4.1.2 Model 2 : Intention to Adoption 49
4.1.3 Comparison results between innovation resistance and intention to adoption 56
4.1.4 Outliers 57
4.2 Additional Analysis 58
4.2.1 Customer group descriptions 59
Chapter 5. Conclusion 77
Appendix 1: Survey questions conducted in this study 93Maste
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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