• ETRI Journal
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• v.24 no.5
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• pp.381-390
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• 2002

We analyze the performance of a telecommunications management network (TMN) system using models of networks of queues, Jackson's theorem, and simulation. TMN systems for managing public asynchronous transfer mode (ATM) networks generally have a four-level hierarchical structure consisting of a network management system, a few element management systems (EMSs), and several pairs of agents and ATM switches. We construct a Jackson's queuing network and present formulae to calculate its performance measures: distributions of queue lengths and waiting times, mean message response time, and maximum throughput. We perform a numerical analysis and a simulation analysis and compare the results.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04b
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• pp.280-282
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• 2001

인터넷의 발달로 웹에서 제공되는 정보와 서비스의 양이 폭발적으로 증가하고 있다. 따라서 사용자들은 보다 쉽게 빠르게 정보를 찾을 수 있도록 지원해 주는 정보 검색 에이전트에 대한 개발을 요구하고 있다. 본 논문에서는 사용자에게 적합한 도서 정보를 검색 및 추천하는 멀티 에이전트 시스템을 설계한다. 그리고 여러 에이전트 사이의 행동을 제어하는 CA(Coordination Agent) 에이전트의 조정 기능과 각 에이전트간의 통신을 지원하는 KQML처리의 알고리즘을 구현한다. 구현 결과 CA의 Message Queue 비교를 토한 조정 기능은 IEA(Information Extraction Agent)의 중복된 정보검색을 방지하여 보다 빠르고 효율적인 정보 검색의 효과를 얻을 수 있었고, KQML은 JAVA의 클래스로 구현하여 본 시스템에서 사용된 메시지 이외의 모든 KQML 메시지 처리 기능을 포함할 수 있도록 하였다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.07a
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• pp.223-224
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• 2018

Internet of Things (IoT) 특성상 경량 디바이스를 사용하기 때문에 한정된 메모리 용량과 컴퓨팅 파워를 효율적으로 활용하기 위한 경량 통신 프로토콜이 요구된다. 본 논문에서는 IoT 기기에서 사용하는 경량 프로토콜인 MQTT를 이용해 센서 노드들이 보내는 데이터의 양을 최소화하여 트래픽 효율을 높이는 broker 캐싱을 제안한다. Broker 캐싱은 MQTT에서 센서 노드가 보낸 데이터를 broker가 캐싱해두고, 센서 노드로부터 중복 처리형 패킷을 받았을 때 캐싱한 데이터를 subscriber에게 전송한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.04a
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• pp.297-299
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• 2016

기술의 발달과 융합으로 사물인터넷(Internet of Things; IoT)의 시대가 열렸다. 빅 데이터와 센서의 발달로 인해 정보는 전과 달리 더욱 사용자와 밀접해졌고 다양해졌으며 양 또한 많아졌다. 이와 더불어 IoT 환경은 다양한 기술들이 융합된 구조로 기존 기술들이 가지고 있는 보안 취약점뿐만 아니라 보다 복잡한 보안 문제점들이 발생할 수 있다. 본 논문에서는 IoT 환경에서 서비스나 IoT 기기들이 갖춰야할 보안 요구사항들을 확장성(scalability), 상호운용성(interoperability), 최소 자원 필요성(minimum resource necessity)으로 분류 하고 정의하였으며, IoT 서비스를 제공하기 위해 사용하는 대표적 프로토콜인 MQTT(Message Queue Telemetry Transfer)와 CoAP(Constrained Application Protocol)에 초점을 맞춰 각각의 표준 문서에서 권고하고 있는 보안 기술에 대해 살펴본다. 또한 그런 기술들에 있어서 발생 가능한 보안 취약점들을 분석하고 이를 해결하기 위한 방법을 제시한다.

• Proceedings of the Korea Society for Simulation Conference
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• 2005.11a
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• pp.102-107
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• 2005

PMS(Plant Monitoring System) for simulation is the program for training that users such as instructor, operator, and supervisor can operate the plant virtually. Presented in this paper, are some lessons learned from implementation of PMS for simulation. First, this PMS fer simulation is based on LINUX instead of UNIX. These two OS(Operating System) have different platform and compiler version on it, so debugging needs to be done about variable defining part. Second, In LINUX system, the size of shared memory and message queue is already designated as a default value that user has to set up and use the RTAP DB. Third, to decrease the dummy data size, it has to be changed into binary formation. Lastly, PMS software for simulation provides several environments according to the command, so considered should be status monitoring, alarm, system organization, point and group monitoring, history storage and searching function.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05a
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• pp.129-132
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• 2003

그리드와 같은 대규모 컴퓨팅 자원이 연결되어 이용되는 분산처리 환경에서 가장 중요한 기능중에 하나가 자원 탐색(lookup)기능이다. 찾기 기능은 미리 정해진 형태로 지원을 등록하고 이 정보를 중앙에서 관리하는 단일기관이나 소규모로 분산된 컴퓨팅 자원을 공유하는 환경에서는 문제되지 않는다. 그러나 임의로 가입과 탈퇴가 가능하고 대규모로 자원이 연결된 그리드 환경에서는 빠른 자원 탐색이 성능의 기본 요소가 된다. 이 논문에서 그리드 환경에서 자원탐색 방법으로 분산형 자원탐색 방법인 Chord시스템을 이용하고 자원탐색방법을 신뢰성 있게 유지하기 위해 메시지큐를 이용하여 시스템을 모델링하고 시스템을 설계한 내용을 기술하였다. 이를 위하여 Chord시스템에 Message Queue System을 통합하여 응용 프로그램에서 요청한 자원탐색을 메시지 큐에 저장하여 노드가 failure되거나 네트워크가 분할이 되더라도 메시지 큐에 저장된 내용을 바탕으로 일관성을 유지할 수 있는 방법을 제시하였다.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.6
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• pp.25-35
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• 1998

The control system architecture in switching systems have undergone numerous changes to provide various call processing capability needed in telecommunication services. During call processing in a distributed switching control environment, the delay effect due to communication among main processors or peripheral controllers is one of the limiting factors which affect the system performance. In this paper, we propose a performance model for an IPC(Inter Processor Communication) interface hardware block which is required on the ATM cell-based message processing in a distributed ATM exchange system, and analyze the primary causes which affect the processor performance through the simulation. Consequently, It can be shown that the local CPU of the several components(resources) related to the IPC scheme is a bottleneck factor in achieving the maximum system performance from the simulation results, such as the utilization of each processing component according to the change of the input message rate, and the queue length and processing delay according to input message rate. And we also give some useful results such as the maximum message processing capacity according to the change of the performance of local CPU, and the local CPU maximum throughput according to the change of average message length, which is applicable as a reference data for the improvement or expansion of the ATM control system.

• The Transactions of the Korea Information Processing Society
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• v.6 no.4
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• pp.1058-1070
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• 1999

In this paper, we propose a control model which can control the burst input messages of the BSC(Base Station controller) in mobile communication systems more efficiently and reliably, by dividing the input messages characteristically and using multiprocessor system. Using M/M/c/K queueing model, we briefly analyze proposed model to get characteristic parameters which are required to performance improvement. On the base of the results, we compare our proposed model with the conventional one by using SLAM II with regard to the following factors : the call blocking rate of the input message, the distribution of average queue length, the utilization of process controller(server), and the distribution of average waiting time in queue. In addition, we modified our model which has overload control function for burst input messages, and analyzed its performance.

• 전자공학회논문지 IE
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• v.45 no.1
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• pp.50-57
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• 2008

It is applying the various teaming contents to improve learner's studying desire and effect in E-Learning system. In this learning contents, there are text animation, sound and picture etc. But, multimedia teaming contents which has big file size need much transmission service times. In this paper, I proposed a scheduling technique of LMS to be faster and service efficiently the multimedia learning contents which was managed and processed it in LMS. for this purpose, I used message and scheduler at LMS. While loaming was processed, it saved the result information of learning contents request to LMS. In this case, if the learner request loaming contents request, it could be possible to support the learning contents efficiently to use learning contents information in LMS without connecting to LCMS. As application result of this techniques, at the first learning course, existent techniques displayed faster learning contents service than proposal techniques. But the more learning process, proposal technique is faster service than existent.

• The Journal of Korea Robotics Society
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• v.7 no.4
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• pp.292-298
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• 2012

It is a real-time system that the system correctness depends not only on the correctness of the logical result of the computation but also on the result delivery time. Real-time Operating System (RTOS) is a software that manages the time of a microprocessor to ensure that the most important code runs first so that it is a good building block to design the real-time system. The real-time performance is achieved by using real-time mechanisms through data communication and synchronization of inter-task communication (ITC) between tasks. Therefore, test on the response time of real-time mechanisms is a good measure to predict the performance of real-time systems. This paper aims to analysis the response characteristics of real-time mechanisms in kernel space for real-time embedded Linux: RTAI and Xenomai. The performance evaluations of real-time mechanism depending on the changes of task periods are conducted. Test metrics are jitter of periodic tasks and response time of real-time mechanisms including semaphore, real-time FIFO, Mailbox and Message queue. The periodicity of tasks is relatively consistent for Xenomai but RTAI reveals smaller jitter as an average result. As for real-time mechanisms, semaphore and message transfer mechanism of Xenomai has a superior response to estimate deterministic real-time task execution. But real-time FIFO in RTAI shows faster response. The results are promising to estimate deterministic real-time task execution in implementing real-time systems using real-time embedded Linux.