• Journal of the Institute of Electronics Engineers of Korea CI
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• v.39 no.4
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• pp.38-49
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• 2002

In this paper, we propose a solution for random time-delay in teleoperation via internet using QoS, and show the experimental results of our proposed method. By ensuring a constant bandwidth required for the specific telecontrolled system, we change irregular random time-delay to a predictable time-delay, and so we can control the system with the time-delay shorter than the specified time-delay. Through the experimental results, we show the effectiveness of our proposed method.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.70.3-70.3
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• 2018

외계행성 탐색시스템의 망원경-카메라 제어 시스템 및 소프트웨어 구성과 관측 유틸리티에 대해 소개한다. 망원경 제어 소프트웨어는 천문 위치보정, 포인팅, 돔 회전 등을 담당하는 PC-TCS 프로그램, 망원경 적경-적위 축 서보 제어를 담당하는 full-closed loop PID 컨트롤 프로그램, 포커서, 필터박스, 돔 셔터, 주경냉각, 온도 모니터 등의 보조 시스템을 제어하는 AUX controls 프로그램으로 구성된다. 카메라 제어 소프트웨어는 모자이크로 구성된 여러 CCD를 각각 독립적으로 제어하는 IC(Instrument Control) 패키지와 이들을 총괄 제어하는 ICS(IC Science) 패키지로 구성되며 망원경과 카메라 소프트웨어의 인터페이스 역할을 하는 TCS Agent 프로그램이 포함된다. 관측 진행을 돕는 유틸리티로서 관측제어 명령어 입력 및 관측 스크립트 구동 기능을 제공하는 OBS Agent 프로그램과 가이드 CCD를 이용한 시상 모니터링 및 자동초점조정 프로그램을 개발하여 활용하고 있다. 각 소프트웨어는 UDP, TCP/IP, RS-232, Redis server 등 다양한 인터페이스를 통하여 서로 통신하며, CCD 영상 자료 전달을 위해 RAM(Random Access Memory) 디스크와 Network File System(NSF)을 이용하고 있다.

• Journal of the Korea Institute of Military Science and Technology
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• v.8 no.4 s.23
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• pp.58-67
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• 2005

To overcome limitations of test scope, schedule and cost, M&S(Modeling & Simulation) technique has been applied for T&E(Test and Evaluation) of the state-of-art weapon systems. This paper proposes an air defense simulation software framework to reduce both redundancy an[1 programming errors in system simulator. The proposed framework consists of a 'model' and a 'middleware' The 'middleware' is a reliable communication service layer that supports not only HLA(High Level Architecture) which is an international standard in M&S but also TCP/IP, UDP and etc. The main role of 'model' is to schedule and to run the real-time distributed simulation. The proposed framework has been applied to M-SAM(Middle range Surface to Air Missile) system simulator. The proposed framework's scheduling and communication performance results are satisfactory and were measured by hardwired NTP(Network Timer Protocol) time-stamp with GPS(Global Positioning System) timer for better precision.

• Journal of Convergence for Information Technology
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• v.7 no.6
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• pp.173-179
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• 2017

Recently, with the development of IoT, there have been increasing cases of transmitting and receiving data by connecting more than one devices supporting various communication methods. In this paper, we propose a multi-terminal emulator supporting various communication methods. The system supports multiple channel connections for each communication method, schedules data transmission, collects communication statistics, represents them into graphs, and stores log records. By using this system, it is possible to test the communication connection between multiple devices, and it is expected to provide convenience for IoT system development.

• Journal of Korea Society of Industrial Information Systems
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• v.10 no.2
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• pp.67-75
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• 2005

In this paper, we design and implement real time IP security packet analyzer on IPv4 and IPv6 network. This packet analyzer sniffs and analyzes the packets generated by the protocols that are used by IPsec, IKE, IPv4 and IPv6 such as AH, ESP, ISAKMP, IP, ICMP and so on. The purpose of this analyzer is to check current security status of the network automatically. In this paper we provide implementation details and the examples of security evaluation by using our security packet analyzer system.

• Journal of Korea Society of Digital Industry and Information Management
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• v.15 no.1
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• pp.21-28
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• 2019

Internet of Things(IoT) is a technology or environment that collects data by attaching sensors to objects and transmits the collected information to each other through wired / wireless communication in real time. It is expected that when the Internet of objects is activated, many objects can identify and recognize each other by themselves and provide various services to facilitate our lives through mutual information exchange. In addition, the internet market for things is growing rapidly each year, and various IT technologies are expected to converge. In the Internet environment of objects, data exchange technology between object devices, that is, message protocol, is classified as one of important technologies. In this paper, we examine various lightweight message protocols suitable for the Internet environment of objects, and compare the reliability of the CoAP protocol structure with the MQTT protocol for a limited environment. Finally, we confirm the reliability of TCP / TLS and WebSockets-based CoAP transmission protocol of IETF's CoRE WG that can use various transport layers other than UDP in Internet environment including cloud infrastructure.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1233-1236
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• 2009

현재 다량의 네트워크 대역폭을 소모하는 응용 프로그램 트래픽을 확인하고 분류하는데 많은 방법들이 사용되고 있지만 정통적인 트래픽 분류 방법론인, 포트 번호, ip 등 등의 헤더 정보만으로는 응용 프로그램의 트랙픽을 정확하게 분류하지 못한다. 최근 동적인 포트 번호를 사용하는 새로운 트래픽 응용의 등장과 방화벽을 통과하기 위한 포트번호 변경으로 인하여 전통적인 TCP/UDP 헤더 기반의 트랙픽 분류 방법은 부정확해지고 있다. 이러한 트래픽을 정확하게 식별하고 분류하기 위해서는 패킷의 페이로드 내용에 대한 조사도 병행되어야 하고 시그니처 기반의 식별 방법을 사용하여야 한다. 하지만 이 방법은 정확도가 높은 반면 시그니처의 목록을 매번 최신 상태로 유지하여야 하는 단점과 길어지는 탐색 시간에 따른 시스템 부하의 문제를 가지고 있다. 본 연구에서는 이러한 단점을 향상시키는 목적으로 새로운 시그니처 기반의 해쉬 테이블에 캐시를 이용한 방법론인 효율적인 알고리즘을 제안하고 시그니처의 자료구조와 실제 패킷과 시그니처의 비교 방식을 수정함으로써 효율성을 높이는데 목적을 두고 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.12
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• pp.1134-1149
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• 2013

Pub/sub system enables data users to access any necessary data without knowledge of the data producer and synchronization with the data producer. It is widely used as the middleware technology for the data-centric services. DDS (Data Distribution Service) is a standard middleware supported by the OMG (Object Management Group), one of global standardization organizations. It is considered quite useful as a standard middleware for US military services. However, it is well-known that it takes considerably long time in searching the Participants and Endpoints in the system, especially when the system is booting up. In this paper, we propose a discovery scheme to reduce the latency when the participants and Endpoints are densely distributed in a small area. We propose to modify the standard DDS discovery process in three folds. First, we integrate the Endpoint discovery process with the Participant discovery process. Second, we reduce the number of connections per participant during the discovery process by adopting the concept of successors in Distributed Hashing scheme. Third, instead of UDP, the participants are connected through TCP to exploit the reliable delivery feature of TCP. We evaluated the performance of our scheme by comparing with the standard DDS discovery process. The evaluation results show that our scheme achieves quite lower discovery latency in case that the Participants and the Endpoints are densely distributed in a local network.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.1
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• pp.78-85
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• 2014

The Mu-communication board supported by hybrid communication is designed with Cortex M3, which is a low power energy consumption 32-bit microcontroller. The Cortex M3 microcontroller has UART(Universal asynchronous receiver/transmitter) ports which can set appropriately using the command line interpreter (CLI) program with each port. URAT ports are used for hybrid communication modems, GPS modules, etc. When the socket type was compared with the short message service type, the socket type was proven to be better. By improving the receiving performance in the control and management system of the AtoN, data loss was minimized. During the testing of the socket and SMS, data was collected from each buoy for 12 hours every 1 minute and the receiving rate of the data was found to be more than 98.58 % and 99.42 % respectively.

• Journal of KIISE:Information Networking
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• v.34 no.1
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• pp.16-26
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• 2007

It is well known that, in the near future, the lifetime of the IPv4 address space will be limited and available 32-bit IP network addresses will not be left my more. In order to solve such IPv4 address space problem in an effective way, the transition to the new version using IPv6 architecture is inevitably required. This paper presents the design and implementation of IPv4/IPv6 dual stack at the GSM Phone based on Linux Kernel 2.4 IPv6 Protocol Stack. It designs appropriately in GSM Phone environment and it is tested by a network of Linux IPv4/IPv6 dual stack on PPP. The test was processed with a test scenario and it was found that the results were successful.