• Proceedings of the Korean Society of Computer Information Conference
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• 2016.07a
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• pp.33-36
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• 2016

발사통제시스템의 주요 구성장치인 카운트다운 타임 생성 시스템은 카운트다운 신호를 생성하여 타 시스템에 제공하는 임무를 수행한다. 발사 관련 주요 장비들은 카운트다운 타임 생성 장치로부터 수신한 카운트다운 타임 정보에 따라 기능 수행을 하므로 안정적인 카운트다운 타임의 제공이 필수적이다. 따라서 카운트다운 타임 생성 시스템은 신뢰성과 고장 감내성을 보장하기 위한 설계가 요구된다. 이를 위해서는 시스템의 신뢰성을 보장하기 위한 방안으로 구성 장치들을 이중화하고 고장을 실시간 감시하여 고장 발생시 Active 장치에서 Standby 장치로의 절체 운용에 대한 설계가 필요하다. 본 논문에서는 카운트다운 타임 생성 장치의 이중화 설계에 따른 실시간 고장 감지 및 절체 운용 방법과 기능 시험 결과에 대하여 기술하였다.

• Tunnel and Underground Space
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• v.29 no.6
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• pp.394-406
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• 2019

Difficult ground conditions (e.g., fault zone and mixed grounds) are highly probable to appear in subsea and urban tunnels because of the shallow working depth and alluvial characteristics. TBM usually experienced decrease of penetration rate and increase of downtime when it meets these difficult ground conditions. The problems are usually caused by the adverse geological conditions, and it is preferable to determine the optimal operational parameters of TBM based on the previous operational data obtained while excavating a preceding tunnel. This study carried out for efficient TBM excavation in fault zone and mixed grounds. TBM excavation data from the tunnel site in Singapore and the characteristics of the TBM excavation data was analyzed. The key operational parameters (i.e., thrust, torque, and RPM), penetration rate, and downtime were highly influenced by the presence of fault zones and mixed grounds, and the features was discussed. It is expected that the results and main discussions will be useful information for future tunneling projects in similar geological conditions.

• Journal of Internet Computing and Services
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• v.24 no.6
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• pp.137-144
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• 2023

Cyberattack technology is evolving to an unpredictable degree, and it is a situation that can happen 'at any time' rather than 'someday'. Infrastructure that is becoming hyper-connected and global due to cloud computing and the Internet of Things is an environment where cyberattacks can be more damaging than ever, and cyberattacks are still ongoing. Even if damage occurs due to external influences such as cyberattacks or natural disasters, intelligent self-recovery must evolve from a cyber resilience perspective to minimize downtime of cyber assets (OS, WEB, WAS, DB). In this paper, we propose an intelligent self-recovery technology to ensure sustainable cyber resilience when cyber assets fail to function properly due to a cyberattack. The original and updated history of cyber assets is managed in real-time using timeslot design and snapshot backup technology. It is necessary to secure technology that can automatically detect damage situations in conjunction with a commercialized file integrity monitoring program and minimize downtime of cyber assets by analyzing the correlation of backup data to damaged files on an intelligent basis to self-recover to an optimal state. In the future, we plan to research a pilot system that applies the unique functions of self-recovery technology and an operating model that can learn and analyze self-recovery strategies appropriate for cyber assets in damaged states.

• Journal of Internet Computing and Services
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• v.3 no.5
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• pp.31-39
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• 2002

A rapid growth of internet and sudden increase of multimedia data demands for high-speed transfer media and if optimizec usage from the interface system. To achieve this level of network bandwidth, multiple NICs for support of high-speed network bandwidth have been developed and studied. Furthermore, the use of multiple NICs can provide high-speed LAN environment without large network environment modification, supports backward compatibility of current system and reduce overhead. However. if system failure is caused by SPOF(Single Point of Failure) fault of large-capacity multiple NICs, incredible loss will be met because it services large capacity of multimedia data, Therefore, to prevent loss coming from faults, we describe 'Fault tolerance of multiple NICs', which use the fault prevention mechanism. Considering inefficiency of availability and serviceability that is occurred with existing TMR, Primary-Standby approach and Watchdog time mechanism, we propose and design the efficient fault tolerance mechanism, which minimize down time as changing of detection period dynamically. Consequently, the fault tolerance mechanism proposed for reducing overhead time when the fault is occurred, should minimize system downtime overall.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.219-221
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• 2000

최근 인터넷의 초고속 성장과 멀티미디어 데이터의 급격한 증가로 인해서, 고속의 전송매체와 이를 최적으로 이용하기 위한 인터페이스 시스템이 요구되고 있다. 이에 따라, 이더넷이 기가비트 이더넷으로 발전되어 LAN 인터페이스 시스템의 고속화를 이루고 있다. 그러나, 폭발적으로 증가하는 인터넷 환경에서 기가비트 이상의 고속 네트워크 대역폭을 지원하는 NIC(Network Interface Card)가 요구되고 있다. 이를 해결하고자, 기가비트 이상의 고속의 네트워크 대역폭을 지원하는 다중(Multiple) NIC의 연구가 진행되고 있다. 그러나, 고속의 네트워크 대역폭을 지원하는 다중 NIC를 운영할 때, 단일 NIC 결함으로 인해 시스템 운영이 중단되는 현상이 발생할 수 있다. 따라서, 효율적인 결함허용 기법을 적용하여 신뢰성 있는 시스템 운영을 지원할 필요성이 대두되고 있다. 본 논문에서는 기존의 하드웨어 결함 허용기법인 TMR, Primary-Standby Approach, Watchdog Timer 기법에서 발생되는 자원에 대한 가용성과 내구성의 비효율적인 부분을 고려하여, 동적으로 검출주기를 변환하여 다운타임(Downtime)을 최소화할 수 있는 효율적인 결함 허용 메카니즘을 설계하여 제안하고자 한다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.07a
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• pp.261-262
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• 2019

컨트롤러에 의해서 동작 및 운영되는 시스템들은 시스템의 내외부적인 요인으로 고장이 발생한 경우 정상적으로 작동할 수 없으며, 이 경우 2차 문제 발생 및 시스템 복구비용이 요구된다. 본 논문에서는 시스템 내부의 소프트웨어 오류 발생 시 컨트롤러 내의 감시 타이머를 사용하여 다운타임 시점 이전의 상태로 복구하는 알고리즘과, 하드웨어 오류의 경우 별도의 자동 리셋 기능을 통하여 시스템을 재설정하고 재 동작이 가능하도록 하는 기능을 구현한다. 제안 시스템은 시스템이 외부 지원 없이 자체적으로 반영구적인 동작이 가능하도록 함으로써, 시스템의 안정성과 신뢰성을 제공하고 운영 및 관리비용의 절감 효과를 제공한다.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.359-360
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• 2008

본 논문에서는 유진 로봇에서 제공되는 로봇 모션 command를 이용하여 플래시 툴의 타임라인을 기반으로 동작 가능한 안내용 로봇 콘텐츠의 제작방법을 제시한다. 유진 로봇에서 제공되는 로봇 command에서 안내용 콘텐츠의 필요한 명령어를 추출 하고 명령어 템플릿을 제작 한다. 플래시를 이용하여 콘텐츠 제작을 하고, 플래시의 타임라인에 유진 로봇에서 제공되는 command를 삽입한다. 시뮬레이터를 통하여 테스트하여 검증 한 뒤, 로봇에 직접 다운로드 하여 콘텐츠를 실행한다.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.4
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• pp.751-756
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• 2018

In smart factories and industrial IoT, all facilities in a factory are monitored over the Internet, thereby facility can reduce the downtime and increase the availiability by preventive maintenance before it breaks down. The abnormal conditions of the major facilities in the plant are caused by abnormal temperature rise, vibration, and variations in noise. Consequently, it is critical to develop a very small smart device that is easily installed in a small space to enable real-time monitoring of the vibration status of the facility. In this study, smart devices were developed for smart factory fault prediction and robustness management using ultra small micro-controllers with WiFi capabilities and MEMS acceleration sensors.

• The Journal of the Korea Contents Association
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• v.8 no.4
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• pp.10-16
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• 2008

Quantity of encrypted data that transmitted through the network are increasing by development of encipherment technology. We have many problems; it is caused by technical development and service increase of user requests. It is necessary that create a many encryption key in one web application system. As a result, service quality comes to be low because of increased network traffic and system overload. There must be a system. That should be improved in secure service quality to process data. This paper describes a new approach for design and implementation of distributed encryption key processing for web application system. In this paper, it is based on distributed encipherment key, for the purpose of confidentially, integrity and authentication. It can prevent system degradation from server's data bottleneck and can improve service quality. For distributed encipherment system, we use java object activation technology. It can service while some distributed server are fail.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.6
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• pp.393-402
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• 2021

The first TBM introduced in Korea was the gripper TBM, which was applied to the Gudeok Waterway Tunnel in 1985. In the initial stage of the introduction of the gripper TBM, many applications were mainly focused on waterway tunnels (Tunnel Mechanized Construction Design, 2008). Currently, the construction range of gripper TBM in Korea is widely applied to not only waterway tunnels, but also subways, railway tunnels, and TBM+NATM expansion. Overseas, gripper TBM is generally applied, and even when NATM tunnel is applied, it is applied as an exploration tunnel because of the excellent advance rate of gripper TBM and used as an evacuation tunnel after completion. Due to the fast excavation speed, the application of the gripper TBM in the rock section of weathered rock or higher can minimize the environmental and civil complaints caused by creating a large number of work areas when planning long tunnels or mountain tunnels. In this study, the work process of the general gripper TBM was analyzed by analyzing the construction cycle and the gripper TBM with a diameter of 2.6~5.0 m, which was applied the most in Korea. Downtime was investigated and analyzed.