• International Journal of Computer Science & Network Security
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• 제23권6호
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• pp.181-192
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• 2023

Blockchain system brought innovation in the area of accounting, credit monitoring and trade secrets. Consensus algorithm that considered the central component of blockchain, significantly influences performance and security of blockchain system. In this paper we presented four consensus protocols specifically as Proof of Work (PoW), Proof of Stake (PoS), Delegated Proof of Stake (DPoS) and Practical Byzantine Fault-Tolerance (PBFT), we also reviewed different security threats that affect the performance of Consensus Protocols and precisely enlist their counter measures. Further we evaluated the performance of these Consensus Protocols in tabular form based on different parameters. At the end we discussed a comprehensive comparison of Consensus protocols in terms of Throughput, Latency and Scalability. We presume that our results can be beneficial to blockchain system and token economists, practitioners and researchers.

• Journal of Korean Neurosurgical Society
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• 제66권3호
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• pp.308-315
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• 2023

Recent updates in genomic-integrated glioma classification have caused confusion in current clinical practice, as management protocols and health insurance systems are based on evidence from previous diagnostic classifications. The Korean Brain Tumor Society conducted an electronic questionnaire for society members, asking for their ideas on risk group categorization and preferred treatment for each individual diagnosis listed in the new World Health Organization (WHO) classification of gliomas. Additionally, the current off-label drug use (OLDU) protocols for glioma management approved by the Health Insurance Review and Assessment Service (HIRA) in Korea were investigated. A total of 24 responses were collected from 20 major institutes in Korea. A consensus was reached on the dichotomic definition of risk groups for glioma prognosis, using age, performance status, and extent of resection. In selecting management protocols, there was general consistency in decisions according to the WHO grade and the risk group, regardless of the individual diagnosis. As of December 2022, there were 22 OLDU protocols available for the management of gliomas in Korea. The consensus and available options described in this report will be temporarily helpful until there is an accumulation of evidence for effective management under the new classification system for gliomas.

• 한국데이타베이스학회:학술대회논문집
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• 한국데이타베이스학회 1999년도 국제컨퍼런스 디지털컨텐츠 활용을 통한 지식경영의 확산
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• pp.25-66
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• 1999

Focus on Interoperability: There will not be consensus on hardware platforms; There will not be consensus on operating systems; There will not be consensus on network protocols; There will not be consensus on application formats. (omitted)

• 제어로봇시스템학회논문지
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• 제21권5호
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• pp.434-441
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• 2015

In this paper, we propose an inverse optimal distributed protocol for the formation and velocity consensus of nonholonomic mobile robots. The communication among mobile robots is described by a simple undirected graph, and the mobile robots' kinematics are considered. The group of mobile robots driven by the proposed protocols asymptotically achieves the desired formation and group velocity in an inverse optimal fashion. The design of the protocols is based on dynamic feedback linearization and the proposed linear quadratic (LQ) inverse optimal second-order consensus protocol. A numerical simulation is given to verify the effectiveness of the proposed scheme.

• 한국정보과학회논문지:시스템및이론
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• 제27권1호
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• pp.34-43
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• 2000

중복 데이타는 분산 시스템에서 결함을 포용하는 방법 중 하나로 여러 복사본들의 일관성을 유지하기 위하여 복제 제어 프로토콜(replica control protocol)을 필요로 한다. 복제 제어 프로토콜 중 정 족수 동의 기법(quorum consensus method)은 정족수 이상의 동의를 얻어서 데이타에 접근하는 방법이다. 그런데 사이트나 통신 링크의 실패로 인하여 정족수 이상의 동의를 얻을 수 없으면 데이타 접근이 불가능하게 되므로 부족한 정족수를 고스트(ghost)로 대치하는 방법이 필요하다. 고스트는 메타 데이타(meta data)에 상태 정보만을 저장한 프로세스이기 때문에 생성과 관리의 비용을 줄이려면 메타 데이타를 간략화 시키는 것이 중요하다. 따라서 본 논문에서는 동료 집합을 이용하여 메타 데이타를 구성하는 방법을 제안한다. 제안된 방법은 2N+logN 비트만으로 메타 데이타를 구성할 수 있게 하고 동료 집합만을 이용하는 프로토콜이나 동적 선형 보우팅 프로토콜보다 향상된 가용성을 나타낸다. 제안된 방법의 가용성은 마코브 모델(Markov model)을 이용하여 측정하고 그 결과를 다른 프로토콜들과 비교 분석한다.

• Journal of Information Processing Systems
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• 제15권2호
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• pp.251-260
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• 2019

In order to ensure second-order multi-agent systems (MAS) realizing consensus more quickly in a limited time, a new protocol is proposed. In this new protocol, the gradient algorithm of the overall cost function is introduced in the original protocol to enhance the connection between adjacent agents and improve the moving speed of each agent in the MAS. Utilizing Lyapunov stability theory, graph theory and homogeneity theory, sufficient conditions and detailed proof for achieving a finite-time consensus of the MAS are given. Finally, MAS with three following agents and one leading agent is simulated. Moreover, the simulation results indicated that this new protocol could make the system more stable, more robust and convergence faster when compared with other protocols.

• 산업융합연구
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• 제20권6호
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• pp.37-45
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• 2022

사물인터넷(IoT)의 발달과 함께 관련 네트워크 인프라는 외부 해킹과 같은 위협을 보호할 수 있는 새로운 기술이 요구되고 있다. 본 연구는 블록체인 합의 알고리즘을 기반으로 IoT 네트워크를 보호할 수 있는 L-PBFT 합의 알고리즘을 제안한다. 소규모 네트워크에 적합한 블록체인(Private) 모델을 설계하고, 초소형/저전력 IoT 장치를 대상으로 처리 성능을 테스트하고 안정성을 검증했다. 성능 분석 결과 L-PBFT는 노드 수가 적어도 합의 알고리즘의 동작(최소 14%, 최대 29%)을 준수하고, 기존 보안 프로토콜과 다른 신뢰 네트워크(보안 채널 분리)를 구축함을 증명하였다. 본 연구는 4차 산업 융합연구로써 향후 IoT 장치 보안 제품 개발에 도움이 되는 기반 기술이 될 것이다.

• International Journal of Computer Science & Network Security
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• 제21권4호
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• pp.255-263
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• 2021

Smart grid is a fully-automated, bi-directional, power transmission network based on the physical grid system, which combines sensor measurement, computer, information communication, and automatic control technology. Blockchain technology, with its security features, can be integrated with Smart Grids to provide secure and efficient power management and transmission. This paper dicusses the deployment of Blockchain technology in Smart Grid. It presents application areas and protocols in which blockchain can be applied to in securing smart grid. One application of each area is explored in detail, such as efficient peer-to-peer transaction, lower platform costs, faster processes, greater flexibility in power generation to transmission, distribution and power consumption in different energy storage systems, current barriers obstructing the implementation of blockchain applications with some level of maturity in financial services but concepts only in energy and other sectors. Wide range of energy applications suggesting a suitable blockchain architecture in smart grid operations, a sample block structure and the potential blockchain technicalities employed in it. Also, added with efficient data aggregation schemes based on the blockchain technology to overcome the challenges related to privacy and security in the smart grid. Later on, consensus algorithms and protocols are discussed. Monitoring of the usage and statistics of energy distribution systems that can also be used to remotely control energy flow to a particular area. Further, the discussion on the blockchain-based frameworks that helps in the diagnosis and maintenance of smart grid equipment. We have also discussed several commercial implementations of blockchain in the smart grid. Finally, various challenges have been discussed for integrating these technologies. Overall, it can be said at the present point in time that blockchain technology certainly shows a lot of potentials from a customer perspective too and should be further developed by market participants. The approaches seen thus far may have a disruptive effect in the future and might require additional regulatory intervention in an already tightly regulated energy market. If blockchains are to deliver benefits for consumers (whether as consumers or prosumers of energy), a strong focus on consumer issues will be needed.

• 융합보안논문지
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• 제23권1호
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• pp.63-68
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• 2023

본 연구에서는 블록체인 프로토콜과 네트워크 보안에 관련해서 MITM공격 및 DoS/DDoS 공격 등에 강한 대응수준을 갖출 수 있도록 블록체인 구성과 스마트 컨트랙트 상의 암호화 키 관리 방안과 에 대해 연구한다. 암호화 통신 프로토콜과 인증강화를 통한 중간자 공격(MITM)등의 데이터보안 위협에 대응, 노드간의 로드밸런싱과 분산화 된 방식으로 DDoS 공격 대응, 안전한 코딩과 취약점 검사, 안전한 합의알고리즘에 의한 스마트 컨트랙트 보안 강화, 사용자 인증과 권한 부여 강화를 통한 액세스 제어 및 인증, 블록체인 코어 및 노드의 보안성 강화, 기타 블록체인 프로토콜 업데이트 및 보안 강화를 위한 모니터링 시스템 구축 등을 통해 보안성이 강화된 블록체인 기술을 활용할 수 있을 것으로 기대된다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제46권5호
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• pp.358-360
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• 2020

The management of odontogenic keratocysts (OKC) remains a hotly debated topic in oral and maxillofacial surgery. Despite numerous studies and systematic reviews on treatment options, there is a lack of consensus and no accepted protocol on the management of OKC. Hence, the aim of this study was to briefly summarize all large systematic reviews in the literature on the management of OKC and formulate an evidence-based management protocol. Data from five large systematic reviews were combined to calculate the mean recurrence rate for each technique. Decompression followed by enucleation along with adjuvant methods such as application of Carnoy's solution and peripheral ostectomy can result in very low recurrence and is an acceptable first line treatment. The surgical approach should be determined by lesion size, patient age, proximity to vital structures, accessibility, soft tissue/cortical perforation, and if the lesion is recurrent.