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The Korean government funded 12.8 billion USD to 652 research and development (R&D) projects supported by 20 ministries in 2019. Every year, various organizations are supported to conduct R&D projects focusing on selected core technologies by evaluating emerging technologies which industries are planning to develop. To manage the whole cycle of national R&D projects, information sharing on national R&D projects is very essential. The blockchain technology is considered as a core solution to share information reliably and prevent forgery in various fields. For efficient management of national R&D projects, we enhance and analyse the Perfect Sharing Project (PSP)-Platform based on a new blockchain-based platform for information sharing and forgery prevention. It is a shared platform for national ICT R&D projects management with excellent performance in preventing counterfeiting. As a consensus algorithm is very important to prevent forgery in blockchain, we survey not only architectural aspects and examples of the platform but also the consensus algorithms. Considering characteristics of the PSP-Platform, we adopt an atomic proof (POA) consensus algorithm as a new consensus algorithm in this paper. To prove the validity of the POA consensus algorithm, we have conducted experiments. The experiment results show the outstanding performance of the POA consensus algorithm used in the PSP-Platform in terms of block generation delay and block propagation time.

The Korean government funded 12.8 billion USD to 652 research and development (R&D) projects supported by 20 ministries in 2019. Every year, various organizations are supported to conduct R&D projects focusing on selected core technologies by evaluating emerging technologies which industries are planning to develop. To manage the whole cycle of national R&D projects, information sharing on national R&D projects is very essential. The blockchain technology is considered as a core solution to share information reliably and prevent forgery in various fields. For efficient management of national R&D projects, we enhance and analyse the Perfect Sharing Project (PSP)-Platform based on a new blockchain-based platform for information sharing and forgery prevention. It is a shared platform for national ICT R&D projects management with excellent performance in preventing counterfeiting. As a consensus algorithm is very important to prevent forgery in blockchain, we survey not only architectural aspects and examples of the platform but also the consensus algorithms. Considering characteristics of the PSP-Platform, we adopt an atomic proof (POA) consensus algorithm as a new consensus algorithm in this paper. To prove the validity of the POA consensus algorithm, we have conducted experiments. The experiment results show the outstanding performance of the POA consensus algorithm used in the PSP-Platform in terms of block generation delay and block propagation time.

학위논문 (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) 50 ; Master

This study examines algorithm effects on user opinion, utilizing a real-world recommender algorithm of a highly popular video-sharing platform, YouTube. We experimentally manipulate user search/watch history by our custom programming. A controlled laboratory experiment is then conducted to examine whether exposure to algorithmically recommended content reinforces and polarizes political opinions. Results suggest that political self-reinforcement, as indicated by the political emotion-ideology alignment, and affective polarization are heightened by political videos–selected by the YouTube recommender algorithm–based on participants' own search preferences. Suggestions for how to reduce algorithm-induced political polarization and implications of algorithmic personalization for democracy are discussed.

Although they are believed to be unsolvable in general, tractability results suggest that some practical NP-hard problems can be efficiently solved. Combinatorial search algorithms are designed to efficiently explore the usually large solution space of these instances by reducing the search space to feasible regions and using heuristics to efficiently explore these regions. Various mathematical formalisms may be used to express and tackle combinatorial problems, among them the constraint satisfaction problem (CSP) and the propositional satisfiability problem (SAT). These algorithms, or constraint solvers, apply search space reduction through inference techniques, use activity-based heuristics to guide exploration, diversify the searches through frequent restarts, and often learn from their mistakes.In this book the author focuses on knowledge sharing in combinatorial search, the capacity to generate and exploit meaningful information, such as redundant constraints, heuristic hints, and performance measures, during search, which can dramatically improve the performance of a constraint solver. Information can be shared between multiple constraint solvers simultaneously working on the same instance, or information can help achieve good performance while solving a large set of related instances. In the first case, information sharing has to be performed at the expense of the underlying search effort, since a solver has to stop its main effort to prepare and communicate the information to other solvers; on the other hand, not sharing information can incur a cost for the whole system, with solvers potentially exploring unfeasible spaces discovered by other solvers. In the second case, sharing performance measures can be done with little overhead, and the goal is to be able to tune a constraint solver in relation to the characteristics of a new instance – this corresponds to the selection of the most suitable algorithm for solving a given instance. The book is suitable for researchers, practitioners, and graduate students working in the areas of optimization, search, constraints, and computational complexity.

Presented at the National data integrity conference: data sharing: the how, why, when and when not to share held on June 2-3, 2016 at University of Colorado, Denver, Colorado. The National Data Integrity Conference is a gathering of people sharing new challenges and solutions regarding research data and integrity. This conference aims to provide attendees with both an understanding of data integrity issues and impart practical tools and skills to deal with them. Topics addressed will include data privacy, openness, policy, education and the impacts of sharing data, how to do it, when to do it, and when not to. Speakers and audience members come from diverse fields such as: Academic Research; Information Technology; Quality Assurance; Regulatory Compliance; Private Industry; Grant Funding; Government. ; PowerPoint presentation during Lightning Talks given on June 3, 2016. ; Includes bibliographical references.