• Journal of information and communication convergence engineering
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• v.10 no.4
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• pp.321-328
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• 2012

A novel design for a simple rectangular ring with open-ended monopole antenna wireless local area network (WLAN) applications is proposed in this article. The proposed antenna consists of an open-ended rectangular ring, an inverted L-strip, and a rectangular slit in the ground plane, and is fed by a 50 ${\Omega}$ microstrip feed-line. Prototypes of the proposed antenna were designed, fabricated, and tested. Experimental results show that the proposed antenna receives 2.3125-2.775 GHz and 4.8625-6.7125 GHz with a return loss less than -10 dB, covering the required bandwidths of the 2.4/5.2/5.8 GHz WLAN standards. Meanwhile, the 2D radiation patterns and 3D gain performance of the antenna in the operation bands were also observed and discussed.

• Journal of information and communication convergence engineering
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• v.12 no.1
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• pp.1-7
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• 2014

A novel design of a simple circular ring with open-ended monopole antenna for wireless local area network (WLAN) applications is proposed in this article. The proposed antenna consists of an open-ended circular ring and $50-{\Omega}$ microstrip feed-line. The proposed antenna is capable of generating two separate resonant modes with good impedance-matching conditions. A prototype of the proposed antenna is designed, fabricated, and measured. Acceptable agreement between the measurement and simulation results is achieved. Experimental results show that the proposed antenna has operating bandwidths of 1.99-3.04 GHz and 5.08-6.1 GHz with a return loss of less than -10 dB, covering the required bandwidths of the 2.4/5.2/5.8-GHz WLAN standards. This is a microstrip antenna for IEEE 802.11a/b wireless local area networks applications. Meanwhile, the two-dimensional (2D) radiation patterns and three-dimensional (3D) gain performance of the antenna are also observed and discussed.

• Journal of Sensor Science and Technology
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• v.24 no.5
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• pp.299-305
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• 2015

Since the natural disasters such as floods, droughts, heat wave and cold wave are increasing, the need for risk management is necessary to minimize the damage with utilizing IT technology. Also, the monitoring services of disaster response type have been developed and applied. Recently, the open source hardware based on the signal of the sensor, or the monitoring studies have been carried. In this paper, by analyzing a low-cost open source hardware platform such as Beagle board, we examine the utilization of the hardware-based module for sensor monitoring.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.424-426
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• 2012

REST 웹 서비스는 HTTP 프로토콜을 통해 손쉽게 적용 및 배포할 수 있다. 최근 다양한 정보시스템의 데이터베이스가 REST Open API 웹서비스를 통하여 배포되고 있으며, 이는 스마트폰 애플리케이션, 웹(Web) 등의 다양한 분야에서 활용되고 있다. 본 연구는 오픈 API 에 대한 시스템의 성능의 포인트에 서비스 평가를 제공하는 것이다. 본 연구는 REST 오픈 API 의 수행 성능 평가를 통하여 REST 오픈 API 웹 서비스의 확장성에 초점을 둔다. 이를 위해 REST 오픈 API 가 미래에 모바일 클라우드 플랫폼으로써 충분한 성능 및 활용될 수 있는지 검증할 필요가 있다. 본 논문은 큐잉 네트워크(Queueing Network)을 활용하여 REST Open API 웹서비스 서버 시스템을 모델링하고 성능을 분석하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2024.05a
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• pp.381-382
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• 2024

Open RAN(Radio Access Network)을 선도적으로 연구하고 있는 O-RAN Alliance에서는 Open RAN의 E2 인터페이스에서 발생 가능한 보안 위협 중 하나로 MitM(Man-in-the-Middle) 공격을 명시하였다. 그러나 이에 대응하기 위한 보안 요구사항으로는 3계층 보안 프로토콜인 IPsec 사용을 명시하고 있으며, 2계층 공격인 ARP(Address Resolution Protocol) 스푸핑에 대한 요구사항은 명시하고 있지 않다. 따라서 본 논문에서는 MitM 공격 중 하나인 ARP 스푸핑으로부터 E2 인터페이스를 보호하기 위해, Near-RT RIC의 ARP 테이블에서 E2 인터페이스로 연결되는 장비에 대한 MAC 주소를 정적으로 설정할 수 있는 xApp을 제안한다.

• The KIPS Transactions:PartC
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• v.16C no.6
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• pp.747-752
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• 2009

The AUTOSAR(AUTOmotive Open System ARchitecture) is an open software platform for automotive. The AUTOSAR contains the modules of FlexRay that is the next generation automotive network protocol. We have developed the modules including FlexRay State Manager, FlexRay Transport, FlexRay Interface, FlexRay Transceiver Driver and FlexRay Driver based on the standard of the module. This thesis presented not only the result of development but the result of design and implementation. And the developed modules were ported to the microcontroller board and verified.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1987.10a
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• pp.35-35
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• 1987

Consider a job shop that is modelled as an open queueing network of the Jackson(l957) type. All work stations in the shop have the same number of parallel servers. Two problems are studied : the loading of stations and the assignment of servers, which are represented by loading and assingment vectors, respectively. Ma jorization and arrangement orderings are established to order, respectively, the loading and the assignment vectors. It is shown that reducing the loading vector under ma jorizat ion or increasing the assignment vector under arrangement ordering will reduce the congestion in the shop in terms of reducing the total number of jobs(in the sense of likelihood ratio ordering), the maximum queue length(in the sense of stochastic ordering), and the queue-length vector( in the sense of stochastic majorization). The results can be used to supprot production planning in certain job shops, and to aid the desing of storage capacity. (OPEN QUEUEING NETWORK; WJORIZATION; ARRANGEMENT ORDERINC; LIKELIHOOD RATIO ORDERINC; STOCHASTIC ORDERING)

• Journal of the Korean Operations Research and Management Science Society
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• v.22 no.4
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• pp.51-69
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• 1997

Recently Lee et al[5] developed an approximation algorithm for the performance evaluation of the open queueing networks with blocking. This algorithm, which solves the exponential queueing networks with general configuration is developed based on the symmetrical decomposition approach and is reported to have many advantages over the previous algorithmsf. In addition to being very accurate, this algorithm is reported to be quite simple, pretty fast and solves very general configurations. In this study, we show that if a network has a tree-like configurations, the algorithm developed by Lee at al, always converges to the unique solution. To prove the theoretical results pertaining to the algorithm, some properties associated with symmetrical decomposition approach are exploited. The results obtained in this study such as the proofs of convergence of the algorithm as well as uniquences of the solution would contribute to the theoretical study for the non-tandem configurating of open queueing network.

• Electronics and Telecommunications Trends
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• v.29 no.6
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• pp.93-101
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• 2014

기존 하드웨어 중심의 네트워크 인프라를 소프트웨어 중심으로 진화시켜 서비스 유연성과 비즈니스 민첩성을 제고시킬 수 있는 새로운 네트워크 기술로 소프트웨어 정의 네트워킹(SDN: Software-Defined Networking)과 네트워크 기능 가상화(NFV: Network Functions Virtualisation) 기술이 최근 각광을 받고 있다. 빠르게 상용화 단계에 접어든 소프트웨어 정의 네트워킹 기술과 달리, 네트워크 기능 가상화 기술은 표준화 단체를 통한 기술 논의 및 상위 표준문서 작업에 많은 노력이 집중됨에 따라 네트워크 기능 가상화 기술을 개발하고 검증하며 운용할 수 있는 실질적인 플랫폼 개발에 대한 요구가 꾸준히 제기되어 왔다. 본고에서는 최근 Linux Foundation의 Collaborative Project로 발표된 공개 소프트웨어 기반의 네트워크 기능 가상화 플랫폼 개발 프로젝트인 OPNFV(Open Platform for NFV)의 목적과 개발범위 그리고 향후 개발방향을 중심으로 소개한다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.60-63
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• 1997

Recently, factory automation and shop floor control system need a web based remote monitoring technology to control effectively machine tool. This paper describes a web based remote monitoring system which is concerned with open architecture controller for machine tool. The environment of this system consists of a lot of elements such as web server, database, machine tool, pc based controller, client computers and script programs, also which is interconnected by network including intranet or internet. Designed script programs, also which is interconnected by network including intranet or internet. Designed script program service current status and faults information of machine to remote users who want to monitor machine tool. Additionally those have various functions to service we board for q&a, downloading data and information of after-service managers.