• International Journal of Precision Engineering and Manufacturing
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• 제5권2호
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• pp.5-15
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• 2004

A telecooperation system supports synchronous cooperation among all the product development partners and enables compensation of deficits concerning traditional information/communication technologies. By analyzing the product development processes and communication scenarios of a company manufacturing automobile parts, the specifications for the suitable telecooperation system were defined. An integrated telecooperation platform that combines the commercial softwares with the new developed modules for customer-oriented functionalities was created as a product development guideline. Future work is strongly required in order to define the best way to improve the integrated platform, based on the functionality of ERP and PDM systems.

• Nuclear Engineering and Technology
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• 제30권4호
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• pp.298-307
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• 1998

In order to design mutual communication between a distributed control system and a function test facility, we used the Inter-Process Communication(IPC) in two systems and Transmission Control Protocol/Internet Protocol(TCP/IP) protocol. The data from the function test facility are put in the shared memory using an IPC, which is then accessed by the distributed control system through an Application Program Interface(API). The server in the function test facility includes two processes(one for sending and one for receiving), which are generated by the fork function from the client signal. The client in the distributed control system includes two separate programs(one for receiving and one for sending).

• Journal of Positioning, Navigation, and Timing
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• 제5권1호
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• pp.29-36
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• 2016

In this paper, performance on receivers of multilateration (MLAT) system that uses ADS-B signal, which is recently becoming popular, was analyzed to overcome shortcomings of existing aircraft flight control systems or reinforce the capabilities. A link budget was analyzed using a channel model in the airport environment with regard to Local Area Multilateration (LAM) for ground-controlled landing around the airport. In order to detect signals that arrived at the receiver successfully, sensitivity of receiver was analyzed using a signal-to-noise ratio (SNR) worksheet, and a method that improves accuracy of the distance measurement was proposed by adopting a peak estimation using sampling signals. Through simulations, optimum specifications of receivers were analyzed to have high precision positioning of LAM, and accuracy of LAM distance measurements was presented.

• Journal of Astronomy and Space Sciences
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• 제40권4호
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• pp.237-245
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• 2023

Laser communication has been considered as a novel method for earth observation satellites with generation of high data volume. It offers faster data transmission speeds compared to conventional radio frequency (RF) communication due to the short wavelength and narrow beam divergence. However, laser beams are refracted due to atmospheric turbulence between the ground and the satellite. Refracted laser beams, upon reaching the receiver, result in angle-of-arrival (AoA) fluctuation, inducing image dancing and wavefront distortion. These phenomena hinder signal acquisition and lead to signal loss in the course of laser communication. So, precise alignment between the transmitter and receiver is essential to guarantee effective and reliable laser communication, which is achieved by pointing, acquisition, and tracking (PAT) system. In this study, we simulate the effectiveness of tip/tilt compensation for more efficient laser communication in the satellite-ground downlink. By compensating for low-order terms using tip/tilt mirror, we verify the alleviation of AoA fluctuations under both weak and strong atmospheric turbulence conditions. And the performance of tip/tilt correction is analyzed in terms of the AoA fluctuation and collected power on the detector.

• 전력전자학회논문지
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• 제17권6호
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• pp.471-477
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• 2012

In this paper, in order to use module integrated converter using cascaded buck-boost converter for a low battery charger in stand-alone system, a charging algorithm which considers photovoltaic and battery status and PWM controllers which are changed according to charging modes are proposed. The proposed algorithm consists of constant current mode, constant voltage mode and maximum power point tracking mode which enables the battery to charge with maximum power rate. This paper also presents design of cascaded buck-boost converter that is the photovoltaic charger system. A 150W prototype system is built according to verify proposed the charger system and the algorithm.

• 전자공학회논문지
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• 제49권11호
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• pp.97-102
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• 2012

최근 지중 시설물은 공간적 제약에 의하여 관리가 쉽지 않기 때문에 무선 통신 센서 네트워크를 도입하려는 시도가 이루어지고 있다. 수백 MHz ~ 수 GHz 대역의 전자기파를 이용한 통신을 사용할 경우 불균질한 물질에서의 통신 성능의 급격한 변화로 인하여 원활한 통신이 어려운 상황이다. 본 연구에서는 이러한 단점을 극복하기 위하여 자기장을 이용한 통신 시스템을 구축하였다. 3m 토압 및 물의 침투를 막을 수 있는 시설물을 제작하여 무선 통신 센서 네트워크 시스템를 설치하였다. 3m 깊이로 땅을 파서 시설물을 매립한 뒤 통신 성능 테스트를 진행하였다. 그 결과 흙, 돌, 물 등이 불균일하게 분포되어 있는 지중에서도 무선 통신이 원활하게 이루어짐을 확인하였다. 따라서 자기장을 이용한 통신 시스템은 지중 시설물 및 연약 지반 관리, 환경 오염 관리 등에서 활용될 수 있을 것으로 기대된다.

• Journal of Information Technology Applications and Management
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• 제22권2호
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• pp.149-169
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• 2015

This study tried to find out how to overcome multicollinearity problems in the structural equation model by creating a hierarchical construct model about the repurchase intention of social commerce. This study selected, as independent variables, price, quality, service, and social influence, based on literature review about social commerce, and then, as detailed variables of independent variables, selected system quality, information quality, transaction safety, order fulfillment and after-sales service, communication, subjective norms, and reputation. As results of empirical analysis about hierarchical construct model, all the independent variables were accepted having a significant impact on repurchase intention of social commerce. Next, this study analyzed the competition model that eight independent variables of price, system quality, information quality, transaction safety, order fulfillment and after-sales service, communication, subjective norm, and reputation directly influence the repurchase intention of social commerce. As results of empirical analysis, system quality, information quality, transaction safety, communication appeared to be insignificant. This study showed that hierarchical construct model is useful to overcome the multicollinearity problem in structural equational model and to increase explanatory power.

• 한국멀티미디어학회논문지
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• 제24권2호
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• pp.199-207
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• 2021

It is very important to support real-time on the inspection equipment based on Windows. In particular, in the system using MIL-STD-1553B communication, which is widely used in military weapon systems, real-time is required for inspection equipment that uses mostly platforms based on Windows such as Industrial PCs. However, in order to use a complete real-time operating system such as VxWorks, the purchase cost is expensive and the implementation is complicated on the system, so it is not suitable for inspection equipment that requires simple functions to just check go or no-go. Therefore, in this paper, a Real-Time implanted Kernel(RTiK) in the Windows kernel is implanted in order to improve these defects, and real-time performance is implemented for periodically MIL-STD-1553B communication by Deferred Procedure Call(DPC) of Windows. Also, it was verified that the period of up to 2ms was guaranteed with a RDTSC into the EDX:EAX registers for measuring the periodicity.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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• pp.81-84
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• 2005

Various design schemes for network using wireless sensor nodes have been widely studied on the several application areas ranging from the real world information collection to environmental monitor. Currently, the schemes are focused on the design of sensor network for low power consumption, power-aware routing protocol, micro miniature operating system and sensor network middleware. The indoor localization system that identifies the location of the distributed nodes in a wireless sensor network requires features dealing with mobility, plurality and other environmental constraints of a sensor node. In this paper, we present an efficient location system to cope with mobility of multiple mobile nodes by designing a location handler that processes location information selectively depending on the nodes' density in a specific region. In order to resolve plurality of multiple mobile nodes, a routing method for the location system is also proposed to avoid the occurrence of overlapped location data.

• 한국인터넷방송통신학회논문지
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• 제13권6호
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• pp.269-274
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• 2013

본 논문에서는 기존의 피킹 (Picking) 시스템이 가지는 인건비 문제와 유지보수 비용이 많이 드는 단점을 해결하기 위해 지그비 무선 통신을 이용한 피킹 시스템 설계 및 구현방법을 제안한다. 지그비 (Zigbee)를 이용한 신뢰성 있는 데이터 전송을 하기 위해 멀티 라우터 기반 스타-트리 토폴로지를 기본 라우팅 토폴로지로 설정하고 이를 위한 ID 설정 방법과 데이터 송수신 방법에 대해 정의하였다. 실험을 통해 멀티 라우터 기반 피킹 시스템의 데이터 전송 성공률이 최대 20% 더 높다는 것을 확인하였다.