• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1994.11a
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• pp.99-107
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• 1994

For the secure control of the communication satellite, security mechanisms should be employed on the ground station as well as on the spacecraft. In this paper, we present a security architecture fur the spacecraft command security of the communication satellite. An authentication mechanism is also proposed using message authentication code (MAC) based on the Data Encryption Standard (DES) cryptosystem.

• Journal of information and communication convergence engineering
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• v.9 no.6
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• pp.625-628
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• 2011

Dynamic sensor network(DSN) technology which is based on swarming flight type air node offers analyzed and acquired information on target data gathered by air nodes in rotation flight or 3 dimension array flight. Efficient operation of dynamic sensor network based on air node is possible when problems of processing time, data transmission reliability, power consumption and intermittent connectivity are solved. Delay tolerant network (DTN) can be a desirable alternative to solve those problems. DTN using store-and-forward message switching technology is a solution to intermittent network connectivity, long and variable delay time, asymmetric data rates, and high error rates. However, all processes are performed at the bundle layer, so high power consumption, long processing time, and repeated reliability technique occur. DSN based on swarming flight type air node need to adopt store-and-forward message switching technique of DTN, the cancelation scheme of repeated reliability technique, fast processing time with simplified layer composition.

• IEMEK Journal of Embedded Systems and Applications
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• v.10 no.3
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• pp.119-127
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• 2015

In the IoT(Internet of Things) environment, methods that user can access sensor node directly to collect sensing data or manage sensor in a gateway have a limitations. To solve this problem, cloud based sensor network architectures are proposed. In this paper, we proposed CoAP based IoT architecture that a lightweight gateway is used for data gathering instead of using a heavy traditional one and users can request sensing data through IoT applications running in the cloud environment and analyze signaling message cost. By doing so, our system can reduce message cost compared to the traditional gateway based system.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.133-136
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• 2005

EAI(Enterprise Application Integration : 전사적 애플리케이션 통합)는 기업간 또는 기업 내부의 다양하고 이질적인 시스템과 애플리케이션 그리고 비즈니스 프로세서를 통합 하는것[1]이며, 본 논문에서는 기존의 데이타 처리에서 발생하는 문제점인 수신측 장애시 데이터의 손실이 발생하는 것을 방지하기 위한 방법으로 C.M(Certificate Message)방식을 제안하였으며 이를 증명하기 위하여 Ledger File에 Confirm 되지않은 메시지를 보관하여 수신측의 장애 이거나 네트워크 장애에도 Data 손실을 방지하는, Review Ledger File 방식을 적용한 C API 프로그램으로 구현하여 증명함 으로써 수신측 상태가 정상적으로 된 경우에 송신측의 Ledger File 다시 읽어서 재송신하여 그 어떤 장애 상황에도 Data 손실됨을 방지하여 실시간 트랜잭션의 처리에 획기적인 방법을 제시하였고, 기존 EAI 시스템 개발시에 문제점으로 대두된 표준화된 개발 방법이 부재하여 개발 및 유지보수에 많은 비용이 발생한 것에 대하여 본 논문은 표준화 방법을 통하여 해결책을 제시하였고, 또한 Ledger File 및 데이타에 대한 모니터링 방법을 Cobol API 프로그램을 통하여 구현하여 실시간 장애 모니터링 방법을 제시하였다. 마지막으로 결론에서 앞으로의 발전방향에 대하여 논의한다.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.8
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• pp.765-772
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• 2006

The L2 Civil Signal (L2CS) will be transmitted by modernized IIR(IIR-M), IIF and all subsequent GPS satellites. It contains two codes of different length; CM code contains 10,230chips, repeats every 20milliseconds and is modulated with message data, and CL code contains 767,250chips, repeats every 1.5second Z-count and has no data modulation. And the message data is encoded for Forward Error Correction(FEC). The long code length is useful for weak signal, but it also requires very long acquisition time. Therefore, the structure of GPS Ll/L2C Correlator and the fast acquisition scheme are proposed in this paper.

• Journal of IKEEE
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• v.21 no.2
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• pp.115-122
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• 2017

In vehicular safety service, every vehicle broadcasts Basic Safety Message (BSM) periodically to inform neighbor vehicles of host vehicle information. However, this can cause network congestion in a region that is crowded with vehicles resulting in a reduction in the message delivery ratio and an increase in the end-to-end delay. Therefore, it could destabilize the vehicular safety service system. In this paper, in order to improve the congestion control and to consider the hidden node problem, we propose a congestion control scheme using entire network congestion level estimation combined with transmission power control, data rate control and time slot based transmission control algorithm. The performance of this scheme is evaluated using a Qualnet network simulator. The simulation result shows that our scheme mitigates network congestion in heavy traffic cases and enhances network capacity in light traffic cases, so that packet error rate is perfectly within 10% and entire network load level is maintained within 60~70%. Thus, it can be concluded that the proposed congestion control scheme has quite good performance.

• The Journal of Information Technology
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• v.4 no.2
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• pp.1-23
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• 2001

The purpose of this paper is to study the send and receive of the Message in the Bolero System. Bolero System is the business processes and methods, together with the digital information system, which are provided by Bolero International for communicating Messages and Documents and facilitating business transactions, as well as the Bolero Rulebook and Operating Rules governing their use. The advantage of bolero.net include speed, cost and efficiency. First, bolero.net moves cirtical information and transactions more quickly than paper can move. Second, a message costs much less to transmit through bolero.net than via couriers and other paper means. Third, because bolero.net logs and tracks all transactions centrally, less data gets lost and fewer data entry errors occur. Bolero International is the certifier for all certificates used in the Bolero System at present. It takes significant responsibility and liability for the certificates that it issues in each Operational Service Contract. In the future, Bolero International may devolve the task of serving as certifier to one or more other qualified institutions.

• Journal of Ocean Engineering and Technology
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• v.20 no.4 s.71
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• pp.76-82
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• 2006

The large-eddy simulation(LES) technique, based an a message passing interface method(MPI), was applied to investigate the turbulent flaw phenomena around a ship. The Smagorinski model was used in the present LES simulation to simulate the turbulent flaw around a ship. The SPMD(sidsngle program multiple data) technique was used for parallelization of the program using MPI. All computations were performed an a 24-node PC cluster parallel machine, composed of 2.6 GHz CPU, which had been installed in the Advanced Ship Engineering Research Center(ASERC). Numerical simulations were performed for the Wigley hull, and the Series 60 hull(CB=0.6) using 1/4-, 1/2-, 1- and 2-million grid systems and the computational results had been compared to the experimental ones.

• Journal of Korea Society of Digital Industry and Information Management
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• v.16 no.4
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• pp.9-17
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• 2020

When IoT sensor nodes are deployed in areas where data collection is challenging, sensors must be relocated if sensing holes occur due to improper placement of sensors or energy depletion, and data collection is impossible. The sensing hole's cluster header transmits a request message for sensor relocation to an adjacent cluster header through a specific relay node. However, since a specific relay node is frequently used, a member sensor located in a specific cluster area adjacent to the sensing hole can continuously receive the movement message. In this paper, we propose a method that avoids the situation in which the sensing hole cluster header monopolizes a specific relay node and allows the cluster header to use multiple relay nodes fairly. Unlike the existing method in which the relay node immediately responds to the request of the header, the method proposed in this paper solves a ping-pong problem and a problem that the request message is concentrated on a specific relay node by applying a method of responding to the request of the header using a timer. OMNeT++ simulator was used to analyze the performance of the proposed method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.5
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• pp.1446-1465
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• 2022

Diversified SaaS applications allow users more choices to use, according to their own preferences. However, the diversification of SaaS applications also makes it impossible for users to choose the best one. Furthermore, users can't take advantage of the functionality between SaaS applications. In this paper, we propose a platform that provides an SaaS mashup service, by extracting interoperable service functions from SaaS-based applications that independent vendors deploy and supporting a customized service recommendation function through log data binding in the cloud environment. The proposed SaaS mashup service platform consists of a SaaS aggregation framework and a log data binding framework. Each framework was concreted by using Apache Kafka and rule matrix-based recommendation techniques. We present the theoretical basis of implementing the high-performance message-processing function using Kafka. The SaaS mashup service platform, which provides a new type of mashup service by linking SaaS functions based on the above technology described, allows users to combine the required service functions freely and access the results of a rich service-utilization experience, using the SaaS mashup function. The platform developed through SaaS mashup service technology research will enable various flexible SaaS services, expected to contribute to the development of the smart-contents industry and the open market.