• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.285-290
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• 2008

Ministry of Land, Transportation and Marine Affairs has implemented Construction CALS project for improving informatization level of construction industry and for making construction production system efficient. Construction CALS project has been implemented since 1998, however, there has been no attempt to measure how high the informatization level of Construction CALS is. This study measured the informatization level of Construction CALS by using the evaluation index proposed in the former studies. For measuring the level, this study made questions and selected samples, did survey, and analyzed the survey results. According to the results, Construction CALS is excellent for the fast rehabilitation of system errors, the web-base environment of system, the application of standard classification system, and the development of information strategic plan. This study will contribute to find out the informatization level of Construction CALS precisely.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.1109-1111
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• 2017

본 논문은 다양한 센서들과 디바이스들이 실시간으로 정보를 주고 산업 IoT 환경에서 실시간 분산 제어 역할을 하는 마스터 노드(Master Node)인 CPS시스템이 시스템장애 또는 내, 외부적인 요인으로 인해 정상적인 수행을 하지 못할 때 일시적으로 마스터 노드의 기능을 수행할 수 있는 싱크노드(Sink Node)를 선정하여 대리 마스터 노드를 결정하는 방안을 제시한다. 산업 IoT환경에서 마스터 노드의 역할로써 중요한 파라미터들을 선정한다. 이 후 상황에 따라 파라미터들의 가중치를 변경하여 우선순위 알고리즘을 통해 지속적으로 싱크 노드들의 우선순위에 대한 정보를 마스터 노드와 싱크노드들 간 공유하게 된다. 마스터 노드의 결함이 발생 시 우선순위가 높은 싱크노드가 마스터 노드의 역할을 대신 수행하여 예기치 못한 상황에도 데이터를 유지할 수 있도록 한다.

• IE interfaces
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• v.9 no.3
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• pp.81-91
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• 1996

현대의 전기 통신망은 통신서비스의 단순한 제공 수단에서 국가적인 사회간접자본으로 그 역할이 변화되고 있다. 이와 같은 통신망의 역할 변화와 함께 초고속화, 집중화 되는 통신망의 안정성에 대한 체계적인 연구의 중요성은 매우 중요한 문제이다. 통신망의 안정성은 시스템 설계의 신뢰성 확보, 재난에 대한 예방 대책, 재난 관리 시스템 운용, 재해 복구 대책, 사업자간 제휴 등으로 예방 및 대처가 부분적으로 가능하지만 망 사업자의 입장에서는 가능한 자원을 최적으로 활용하여 외부 재해나 내부 장애에도 강건한 구조의 통신망으로 계획하고 설계함이 가장 기초적인 안정성 대책이 된다. 본 논문은 이와 같은 통신망의 안정성을 체계적으로 계획하고 이에 맞게 통신망을 설계하는 일관된 과정(Integrated Network Design Process)을 위한 통신망 안정성에 대한 계층적 모형을 설명하고, 유사동기식 전송 기술에서 최근의 동기식 전송 기술로 대체되고, 향후 ATM 전달 모드로의 진화되는 추세를 감안할 때 필수적인 새로운 통신망 안정성 모형을 제시한다. 특히 기존에는 Logical Layer와 Transmission System Layer로 나누어 계획되고 설계되는 일련의 과정들이 동기식 장비들의 개선된 interworking과 ATM의 유연한 망구조의 장점 때문에 통합되어 계획/설계되어야 하는 필요성과 장단점을 설명하고 최근의 최적화 기술은 이와 같은 통합된 설계 모형에도 효율적이 해결 방안을 제공함을 보여준다. 이와 같은 제시된 통합 방법론/모형과 함께 한국통신의 기간 전송망의 계획과 설계에 사용된 사례를 제시하고, 향후 국가적으로 중요한 관심 사항인 초고속통신망/BISDN의 구축에 효율적으로 응용되기 위한 추가적인 연구 주제와 기대성과를 논의한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.11
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• pp.1989-1995
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• 2006

RAID(Redundant mays of inexpensive disks) were proposed as a way to use parallelism between multiple disks to improve aggregate I/O performance. The emerging of intelligent I/O architecture provides a standard for high performance I/O subsystems and introducer intelligence at the hardware level. With an embedded processor, intelligent I/O adaptors can offload the major I/O processing workload from the CPU and, at the same time, increase the I/O performance. This parer addresses the essential issue in the design of disk scheduling for intelligent I/O devices. In this paper we compare with MB throughput per second and maximum I/O respond time in RAID.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.5
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• pp.498-508
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• 2003

In the field of finance, Trading System of Securities is a very vulnerable application when it faces any small problems just for one minute. Since Trading System changes its environment from mainframes to client/server, its safety becomes the most important factor. Even though most If systems are configured by general guidelines currently, Trading System is an exception that it is configured by specific and rather ad hoc guidelines in order to ensure its safe management. In this thesis, I will prove the validity of specific and ad hoc configuration in the environment of Trading Systems where I use both XA interface system and Non-XA interface to configure its system based on 3-Tier Client/server computing environment through middleware, TP-Monitor, in the X/Open DTP Model. In order to validate the Trading System, I will compare and analyze the error of data of an order and ability to restore using both XA and Non-XA interfaces while testing take-over scenario on the assumption of the system's failure.

• The Journal of Korean Institute of Next Generation Computing
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• v.15 no.3
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• pp.7-15
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• 2019

Cloud computing markets are rapidly growing as cost savings and business innovation are being carried out through ICT worldwide. In line with this paradigm, the nation is striving to introduce cloud computing in various areas, including the public sector and defense sector, through various research. In the defense sector, DIDC was established in 2015 by integrating military, naval, air and military computing centers, and it provides cloud services in the form of IaaS to some systems in the center. In DIDC and various future cloud defense systems, It is an important issue to ensure availability in cloud defense systems in the defense sector because system failures such as network delays and system resource failures are directly linked to the results of battlefields. However, ensuring the highest levels of availability for all systems in the defense cloud can be inefficient, and the efficiency that can be gained from deploying a cloud system can be reduced. In this paper, we classify and define the level of availability of defense cloud systems step by step, and propose the strategy of introducing Erasure coding and failure acceptance systems, and disaster recovery system technology according to each level of availability acquisition.

• Journal of KIISE:Databases
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• v.35 no.1
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• pp.17-28
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• 2008

Recently, main memory access is a performance bottleneck for many computer applications. Cache memory is introduced in order to reduce memory access latency. However, it is possible for cache memory to reduce memory access latency, when desired data are located on cache. EST tree is proposed to solve this problem by improving T tree. However, when doing a range search, EST tree has to search unnecessary nodes. Therefore, this paper proposes $CST^+$ tree which has the merit of CST tree and is possible to do a range search by linking data nodes with linked lists. By experiments, we show that $CST^+$ is $4{\sim}10$ times as fast as CST and $CSB^+$. In addition, rebuilding an index Is an essential step for the database recovery from system failure. In this paper, we propose a fast tree index rebuilding algorithm called MaxPL. MaxPL has no node-split overhead and employs a parallelism for reading the data records and inserting the keys into the index. We show that MaxPL is $2{\sim}11$ times as fast as sequential insert and batch insert.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.7
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• pp.421-428
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• 2006

In this paper, the way of remote installation and back-up of 3-tier structure is introduced for efficient utilizing the cluster system resources distributed at several places. Recently, cluster system is constructed as the system of over hundreds nodes under complex network system mixed with public networks and private networks. Therefore, the as installation method suitable for the large scale cluster system and the remote recovery of failure nodes are important. However the previous researches which are based on 2-tier architecture may not provide the efficient cluster installation and image back-up method when the network of cluster system is composed of several private networks and public networks. In this paper, RISE (Remote Installation Service and Environment) based on the 3-tier architecture is proposed to solve this problem. In our approach, the managing node's role is divided into the global master node (GRISE) and the local master node (LRISE) to provide the efficient initial system deployment and remote failure recovery of distributed cluster system under the various network systems. Also, LRISE's availability is ensured under the complex network environments by adopting the auto-synchronization mechanism between GRISE and LRISE. In this work, a 64-node cluster system with gigabit network system is utilized for the experiment. From the experimental result, the system image with 1.86GB data can be obtained in 5 minutes and 53 seconds and the image-based installation of 64-node system can be carried out in 17 minutes and 53 seconds.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.482-482
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• 2021

자동유량측정시스템은 하천 유량을 실시간으로 측정하기 위한 수문조사시설로 전국 하천 64개 주요 지점에 설치·운영 중이며 실시간으로 운영되는 시스템의 특성상 내·외부 요인으로 인해 자료의 결측이 발생할 수 있다. 주요 결측 요인으로는 계측장비의 고장 및 오작동, 낙뢰로 인한 전원부문제, 시스템 컨트롤러 단순 오류 등이며, 현재 이로 인해 결측이 발생한 경우 현장 방문을 통한 조치 외에는 복구가 불가한 실정이다. 본 연구에서는 현장 유지관리 개선을 통해 자료 결측 최소화 방안을 마련하고자 최근 5년간(2015년~2019년) 수행된 유지관리 점검내역을 검토하였다. 현장 유지관리는 정기적으로 수행되는 정기점검, 수중점검과 장애 발생 시 수행되는 현장점검으로 구분되며 최근 5년간 수행된 점검(1,735회) 중 정기적인 점검을 제외한 현장점검의 경우 총 764회(46%) 수행된 것으로 나타났으며 현장점검 중 유지관리 방법 및 장비 개선 적용 사례를 통해 최소 1일~3일 소요되던 점검 시간이 즉시 조치가 가능한 것으로 나타났다. 시스템 확대 및 기존 장비의 노후로 현장점검은 지속적으로 증가하고 있으며 최근 사회적 상황을 고려하였을 때 사물인터넷(IoT)을 활용한 시설물 개선 등으로 비대면 점검 수행이 가능해짐에 따라 점검 소요시간을 단축하여 보다 효율적인 시설물 운영, 예산 절감, 자료의 연속성 확보 등이 가능할 것으로 판단된다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.1
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• pp.49-60
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• 2015

Smart Grid devices are the major components of the Smart Grid. They collect and process a variety informations relating power services and support intelligent power services by exchanging informations with other SG devices or systems. However, If a SG device is attacked, the device can provide attack route to attacker and attacker can attack other SG devices or systems using the route. It may cause problem in power services. So, when cyber incident is happened, we need to acquire and examine digital evidence of SG device quickly to secure availability of SG. In this paper, we designed remote evidence acquisition system to acquire digital evidences from SG devices to response quickly to incidents of SG devices. To achieve this, we analyzed operating environment of SG devices and thought remote digital evidence acquisition system of SG devices will be more effective than remote digital evidence acquisition system targeted general IT devices. So, we introduce design method for SG devices remote evidence acquisition system considered operating environment of SG devices.