• Journal of Institute of Control, Robotics and Systems
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• v.18 no.8
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• pp.774-779
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• 2012

We design and implement a RTT (Round Trip Time) based TCP (Transmission Control Protocol) for USN (Ubiquitous Sensor Network). We adopt a basic update algorithm for window size from FAST TCP that uses the queuing delay at link as the congestion measure. The designed TCP estimates the queuing delay at link from the measured RTT in the network layer, and updates the window size based on the estimated queuing delay. The designed TCP allows to utilize the full capacity of USN links and avoids the waste of the given link capacity that is common without the flow control in the transport layer. The experiment results show that the window size of the sender converges within a small range of variations without any packet loss, and verify the stability and performance of the designed TCP.

• Convergence Security Journal
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• v.19 no.3
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• pp.3-12
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• 2019

BGP is the most important protocol among routing protocols that exchange routing information to create routing tables and update changed information so that users on the Internet can send information to destination systems. This paper analyzes how to prevent malicious attacks and problems caused by network administrator's mistakes by using vulnerabilities in BGPv4 that are currently used. We analyzed the attack methods by performing the actual attack experiment on the AS-PATH attack, which is the attack method for BGP's representative security vulnerability, and proposed the algorithm to identify the AS-PATH attack.

• Journal of Communications and Networks
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• v.17 no.2
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• pp.203-209
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• 2015

Although mobile applications are an essential characteristic of wireless sensor networks, most existing media access control (MAC) protocols focus primarily on static networks. In these protocols, fixed periodic neighbor discovery and schedule updating are used to connect and synchronize neighbors to provide successful data transmission; however, they cannot adapt to mobile speed variation and degrade the network performance dramatically. In this paper, we propose a mobile-supporting mechanism for MAC protocols, in which the decision to update the neighbors of a mobile node is made adaptively according to the mobile speed. Analysis and simulation results demonstrate that the mechanism efficiently avoids the disconnection of amobile node from its neighbors and achieves a better performance as compared with fixed periodic neighbor discovery.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.1
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• pp.155-161
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• 2012

The firmware upgrade, which is remotely performed, is an essential function in smart metering or AMI (Advanced Metering Infrastructure). In other words, the AMI software and firmware can be switched for maintaining and improvement without replacement of H/W devices in AMI environment. Also, if number and type of devices are increase, the demand of remote update service will be increased. Through the firmware upgrade service remotely, the electric power corporation may be able to benefit various fields. For example, there are to adapt more easily in many environments, real-time service and to cut maintenance costs. In this paper, we proposed to design an international level FUMS(Firmware Upgrade Management System) which includes requirement function, architecture and protocol related with DCU, Smart Meter.

• Proceedings of the KAIS Fall Conference
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• 2007.11a
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• pp.205-208
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• 2007

본 논문에서 마이크로 및 피코 셀 환경에 적합한 인증된 바인딩 업데이트 프로토콜을 제안한다. 제안하는 프로토콜은 CGA (Cryptographically Generated Address) 기반의 티켓 방식을 이용한다. 이 방식은 호스트의 공개키와 서브넷 프리픽스를 이용하여 생성한다. 또한 초기통신 시에 대응노드는 이동 노드에게 홈 에이전트를 통한 티켓을 발행한다. 이는 이동노드와 대응노드 간에 직접 바인딩 갱신을 할 수 있도록 도와준다. 또한 대응노드는 티켓 확인을 통한 이동노드를 인증하고 바인딩 업데이트를 안전하게 수행한다. 몇 가지 공격 시나리오를 통한 프로토콜의 안전성을 분석한다. 마지막으로 결론 및 향후 연구 방향에 대해서 제시한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.04a
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• pp.699-701
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• 2010

스마트폰, PDA와 같은 다양한 무선통신 단말들이 출현하면서 차량 내에서도 인터넷 서비스를 사용하려는 사용자들이 증가하고 있다. 이에 따라 이동중인 차량 내에서 인터넷 엑세스를 위해, 그리고 차량이 다른 서브넷 사이를 이동하더라도 시그널링 오버헤드가 크지 않게 하기 위해, network mobility basic support (NEMO BS) protocol이 제안되었다. 그러나 차량 내의 노드들에게 QoS를 지원하기 위해서 session admission 기법 등이 필요하다. 이 때, 차량 내에서 발생하는 세션은 new session과 handoff session으로 구분할 수 있는데, new session의 봉쇄보다 handoff session의 봉쇄가 서비스 만족도 측면에서 더 큰 임팩트를 가진다. 따라서 본 논문에서는 차량 외부에서 차량으로 이동한 노드들의 handoff session 봉쇄확률을 줄이기 위한 늦은 바인딩 업데이트 기법을 제안한다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.49 no.4
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• pp.218-222
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• 2023

Re-ankylosis is a common postoperative complication of temporomandibular joint (TMJ) ankylosis surgery. Various surgical options to prevent re-ankylosis, both with and without interpositional material, have been discussed in the literature. However, no standardized protocol has been suggested for management or prevention of TMJ ankylosis. This paper discusses the probable causes behind TMJ re-ankylosis and presents a case of unilateral TMJ re-ankylosis, which was managed by gap arthroplasty using an autologous abdominal dermal fat graft as an interpositional material and closely monitored for signs of relapse. Autologous fat graft acted as an effective barrier between the glenoid fossa and mandibular condyle, thus preventing dead space, hematoma and heterotrophic bone formation. A brief review of the literature and update on TMJ re-ankylosis are also presented.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.05a
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• pp.55-58
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• 2021

우주 네트워크는 고지연성, 저신뢰성 등 기존의 지상 네트워크와는 차별화된 특성을 가진다. 또한 높은 예산이 투입되는 우주 임무 특성상 지상 시험 시 발견되지 않은 소프트웨어 버그가 막대한 비용을 초래할 수 있다. 그러나 현재까지 우주 네트워크 환경에 특화된 소프트웨어 업데이트 관련 연구는 부족한 실정이다. 따라서 본 연구에서는 Asynchronous Management Protocol(AMP)을 기반으로 원격 소프트웨어 업데이트 프레임워크를 새롭게 제안한다. 해당 프레임워크는 Interplanetary Overlay Network(ION) 소프트웨어를 사용하여 프로토타입을 구현하였으며, 실제 업데이트 케이스를 적용하여 기능 및 실사용성을 검증하였다.

• Journal of the Korea Convergence Society
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• v.7 no.1
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• pp.49-55
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• 2016

In a delegate authentication, a user can lend his/her own authentication data to the third parties to let them be authenticated instead of himself/herself. The user authentication schemes based on the memory of unique data such as password, are vulnerable to this type of attack. Biometric authentication could minimize the risk of delegate authentication since it uses the biometric data unique by each person. Group authentication scheme is used to prove that each group member belongs to the corresponding group. For applications such as an electronic voting or a mobile meeting where the number of group members is changing dynamically, a new group authentication method is needed to reflect the status of group in real time. In this paper, we propose biometric authentication based dynamic group signature scheme. The proposed scheme is composed of biometric key generation, group public key creation, group signature generation, group signature verification and member update protocols. The proposed member update protocol is secure against colluding attacks of existing members and could reflect group status in real time.

• Journal of the Korea Society of Computer and Information
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• v.12 no.6
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• pp.235-242
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• 2007

Network Mobility Basic Support protocol reduces location-update signaling by making network movements transparent to the mobile nodes (MNs) behind the mobile router (MR), but causes some problems such as sub-optimal routing and multiple encapsulations. This paper proposes an Route Optimization Employing HMIP Extension for Mobile Networks (ROHMIP) scheme for nested nubile networks support which introduces HMIP concept with relation information between MNNs behind a MR and the MR in order to localize handoff, to optimize routing and especially reduce handoff signal overhead. With ROHMIP, a mobile network node (MNN) behind a MR performs route optimization with a correspondent node (CN) as the MR sends a binding update message (BU) to mobility anchor point (MAP) via root-MR on behalf of all active MNNs when the mobile network moves. This paper describes the new mechanisms and provides simulation results which indicate that our proposal reduces transmission delay, handoff latency and signaling overhead.