• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.10
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• pp.2307-2314
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• 2015

This paper focuses on the generation algorithm of BeiDou pseudorange correction (PRC) and simulation based performance verification for design of Differential Global Navigation Satellite System (DGNSS) reference station and integrity monitor (RSIM) in order to prepare for recapitalization of DGNSS. First of all, it discusses the International standard on DGNSS RSIM, based on the interface control document (ICD) for BeiDou, estimates the satellite position using satellite clock offset and user receiver clock offset, and the system time offset between Global Positioning System (GPS) and BeiDou. Using the performance verification platform interfaced with GNSS (GPS/BeiDou) simulator, it calculates the BeiDou pseudorange corrections , compares the results of position accuracy with GPS/DGPS. As the test results, this paper verified to meet the performance of position accuracy for DGNSS RSIM operation required on Radio Technical Commission for Maritime Services (RTCM) standard.

• Journal of Navigation and Port Research
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• v.26 no.4
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• pp.419-426
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• 2002

The conventional RTK-GPS technique has many problems which are permission using RF wireless modem, influence of geographic obstacle using radio wave, frequency interference, finiteness of frequency resources. To solve these problems, in this paper, we designed the DGPS correction message transmission system as a method to substitute the RF wireless modem of RTK-DGPS receiver. Then the interface module was designed and implemented for linkage of GPS receiver and mobile phone. As a result worked differential surveying using receiving correction message using RS-232C and communication control, users of mobile station were worked differential surveying correction between mobile phones. Interface module system was received the same result of precision which was compared RF wireless modem system.

• Journal of KIISE:Information Networking
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• v.35 no.5
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• pp.415-424
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• 2008

In this paper, we compare the QoS performance enhancement schemes according to the network architecture of mobile WiMAX system in order to improve the end-to-end QoS performance and propose QoS parameter mapping method and IP packet scheduling algorithm. To evaluate the end-to-end QoS performance, we implemented an end-to-end simulator of mobile WiMAX system using OPNET. Simulation results show that the proposed QoS parameter mapping scheme reduces the average delay of VoIP packet and improves uplink resource efficiency. And also, when the proposed IP packet scheduling algorithm is applied to the system, the end-to-end packet transmission delay of VoIP service can be reduced by 44-67 percent compared to FIFO and WRR scheduler.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.6
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• pp.1155-1160
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• 2017

This paper describes a system implementation for the automatic inspection on the ventilating electronic device based on the reliability improvement. To be enhancement, the inspection error is minimized by the automatic inspection system on the ventilating apparatuses against the manual inspecting system. The system consists of the control system, software structure and monitoring system to be scanning the inspection processing. The inspection system for reliability improvement is evaluated in Gage Repeatability and Reproducibility. The experimental results are improved about 2 times inspecting speed, measured error ${\pm}0.02V$, effectiveness of discriminating performance 15%, missing probability 17% and false alarm probability 12% respectively in comparing with the manual inspection based on the wind pressure sensor. The system will be also improved more by making database and product bar codes for the total quality control system to the effective reliability enhancement in the future.

• Journal of KIISE:Software and Applications
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• v.33 no.4
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• pp.388-401
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• 2006

A tool for analyzing and testing software in real-time is required for the efficient development of highly reliable real-time mobile embedded software This too] requires various technologies, such as source code based white-box test and real-time system monitoring and control. The tool also should be designed to improve reusability and portability by considering the interaction with other kinds of real-time system. This paper identifies and analyzes the functional requirements for the test tool on real-time mobile embedded software and suggests an adequate tool architecture based on the collected requirements. It also suggests the specific implementation technology and architecture design pattern to support the tool's expandability and portability.

• Journal of the Korea Society of Computer and Information
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• v.20 no.5
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• pp.99-106
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• 2015

This research is focused on the development of the proprietary database embedded in the OTT device, which is used for searching and indexing video contents, and also the development of the search algorithm in the form of the critical components of the interface application with the OTT's database to provide video query searching, such as remote control smartphone application. As the number of available channels has increased to anywhere from dozens to hundreds of channels, it has become increasingly difficult for the viewer to find programs they want to watch. To address this issue, content providers are now in need of methods to recommend programs catering to each viewer's preference. the present study aims provide of the algorithm which recommends contents of OTT program by analyzing personal watching pattern based on one's history.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.197-200
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• 2002

The current Inn technique is many problems that is permission of radio station using RF Wireless Modem, that is influence of geographic obstacle using radio wave, that is frequency interference, that is finiteness of frequency resources. In this paper, we are solved many elements, IM replaces RF Wireless Modem, we suggest transmission technique of correction message using mobile phone, we researched Interface Module development which is linkage of DGPS receiver and mobile phone. IM can transmit correction message passing RS-232 port and modem communication control. IM of base station is initialized RS-232 port and modem to move station for correction message transmission, IM waited response mode. IM of move station is initialized RS-232 port and modem, IM requests hand shaking to base station, completed connection establishment. Users are worked Differential surveying using receiving correction message between mobile phones.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.4
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• pp.405-418
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• 2014

Fuel cells are suitable for a power plant of a unmanned aerial vehicle (UAV) as it is not only environmentally friendly and quiet but also more efficient than an internal combustion engine. A fuel cell hybrid UAV has better performance in endurance than a fuel cell only or battery only UAV. One of the key purposes of making fuel cell hybrid UAVs is having long endurance and now maximum 26 hours of flight is possible. Because optimal design and control methods for fuel cell hybrid UAVs are absolutely needed for their long endurance we have to check the methods. The aircraft made by using application-integrated design method has less BOP mass and better performances. The optimal design and control methods are generally based on computer simulations or Hardware-In-The-Loop simulations by using dynamic models for their design and control. The Hardware-In-The-Loop simulation (HILS) is to use a hardware device like a fuel cell stack as well as a simulation program and it allows for making optimally designed applications. This paper introduce efficient methods of design, control and evaluation for the fuel cell hybrid UAVs.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.7
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• pp.949-955
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• 2018

Hardware-in-the-loop (HIL) simulation is a technique that can be employed for developing and testing complex real-time embedded systems. HIL simulation provides an effective platform for verifying power management system (PMS) performance of liquefied natural gas carriers, which are high value-added vessels such as offshore plants. However, HIL tests conducted by research institutes, including domestic shipyards, can be protracted. To address the said issue, this study proposes a field programmable gate array (FPGA) based PMS-HIL simulator that comprises a power supply, consumer, control console, and main switchboard. The proposed HIL simulation platform incorporated actual equipment data while conducting load sharing PMS tests. The proposed system was verified through symmetric, asymmetric, and fixed load sharing tests. The proposed system can thus potentially replace the standard factory acceptance tests. Furthermore, the proposed simulator can be helpful in developing additional systems for vessel automation and autonomous operation, including the development of energy management systems.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.11-11
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• 2023

2020년 기준 우리나라 전체 지하수 시설은 총 1,659천개소, 이용량은 2,916백만m³/년, 년간 지하수 개발가능량은 130억m³대비 22.3%이다(환경부 등, 2021). 단위면적당 지하수 시설수와 이용량은 16.8개소/km², 29,168m³/년/km²(81.1m3/일/km²)이다. 이러한 자료는 가뭄 대응시 신규 관정 개발도 필요하지만, 기존에 개발된 관정들을 최대한 효율적으로 활용하는 방안을 우선적으로 고려해야 한다는 것을 시사한다. 관정들을 상호 연계하게 되면 여러 개의 관정에서 나오는 물을 합하여 총량을 늘릴 수 있기 때문에, 가뭄 등 비상시에 일시적으로 다량의 물을 공급할 수 있다. 또한, 평상시에도 적절한 양수량 조절을 통해 지하수 자원의 손실을 막고 수위 저하에 의한 문제를 최소화할 수 있다. 관정연계시스템(well network system, WNS)은 기존 관정들을 가상의(virtually) 또는 물리적(physical) 연계를 하여, 최적의 지하수를 공급할 수 있는 시스템으로 정의할 수 있다. 가뭄 대응 및 효율적 지하수 자원 활용을 위한 관정연계시스템 개발과 실증을 위해 홍성군 서부면 양곡리 일대에 양수제어, 관로시설, 물탱크 등 물리적인 시설을 시험 설치하여 운영하고 있다. 또한, 관정연계시스템은 ICT 기술과 지하수관리 기법을 연동하여 지하수 관정들을 연계하고 최적으로 운영할 수 있는 하나의 의사결정시스템으로서 관정연계 플랫폼을 개발하였다. 관정연계 플랫폼은 웹기반으로 개발되었으며, 대수층의 수리지질 특성, 수요에 기반한 물공급량 평가, 관정 연계 시나리오 및 최적 운영 알고리즘, 지하수 모델링 등이 가능하도록 각각의 모듈들이 구성 및 통합·운영 되도록 설계되었다. 본 시스템 개발을 통해 가뭄 발생시 현장에서 신속히 지하수로 물을 공급할 수 있으며, 신규 관정 개발에 드는 비용을 절약할 수 있고, 기존 시설을 활용하기 때문에 새로운 수자원 건설 인프라 구축 비용도 절감할 수 있을 것이다. 또한, 개별관정에 대한 이용률 제고와 지하수관리도 보다 체계적, 과학적으로 할 수 있을 것으로 기대한다. 하지만, 이러한 시스템이 제대로 운영 및 보급되기 위해서는 관정연계와 관련한 법제도적 보완과 함께, 지역사회의 공적자원으로서의 지하수에 대한 인식개선과 지하수의 개발 및 보전, 적합한 합리적 배분·이용 등 적극적인 협조가 이루어져야 한다.