• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.581-584
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• 2018

최근 다양한 분야에서 대량의 데이터를 수집하여 처리하고 분석하는 빅데이터 기술이 활용되고 있다. 빅데이터 분석을 위해서는 데이터 시각화 기술이 필수적이다. 본 논문에서는 REST API를 사용하여 시계열 데이터베이스에 데이터를 질의하고, 응답받은 시계열 데이터를 다양한 형태의 차트로 시각화하는 마이크로서비스(Graphgen)를 설계하고 구현한다. 이 서비스는 데이터의 변동에 따라 실시간으로 시각화 객체를 갱신하며, 대용량 데이터 처리의 성능저하를 최소화하도록 개발된다. Graphgen은 InfluxDB와 OpenTSDB 시계열 데이터베이스와 Bokeh 시각화 라이브러리를 지원하며, 추후 서비스 확장이 용이하도록 개발된다. 또한 부하 분산과 통합 배포 관리를 위하여 컨테이너를 기반으로 개발된다.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.4
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• pp.833-845
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• 2001

Quantitative Feedback Theory(QFT) has been used to design a robust power system stabilizer(PSS) to improve transient and dynamic stabilities of a power system. This design technique is basically accomplished in frequency domain. The most important feature of QFT is that it is able to deal with the design problem of complicated uncertain plants. A basic idea in QFT design is the translation of closed-loop frequency-domain specifications into Nichols chart domains specifying the allowable range of the nominal open-loop response and then to design a controller by using the gain-phase loop shaping technique. This paper introduces a new algorithm to compute QFT bounds more efficiently. The propose QFT design method ensures a satisfactory performance of the PSS under a wide range of power system operating conditions.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.04a
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• pp.702-705
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• 2015

본 논문에서는 하듐 환경에서 시스템 정보의 이상탐지를 위한 시각화 기능을 설계 및 구현한다. 제안한 이상탐지 시각화 기능은 크게 세 단계로 구분된다. 먼저, 각 노드로부터 시스템 로그 데이터(캐시 및 메인 메모리)를 수집하여 하이브(Hive) 저장한다. 그리고 저장한 데이터에 3-시그마 규칙을 적용하여 이상탐지를 수행한 후 관계형 데이터베이스에 적합하도록 재가공한다. 마지막으로, 스쿱(Sqoop)을 통해 RDBMS(MariaDB)에 이상탕지 결과를 저장하고, DHTMLX 차트 라이브러리를 사용하여 이를 시각화한다. 시각화 결과, 로그 데이터의 이상탐지와 데이터간의 상관관계를 직관적으로 이해할 수 있게 되었다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.2
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• pp.171-178
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• 1998

Generally, the output matching circuit has the most influence to the output power of oscillator and existing method for output matching has difficulty for making the optimum output matching circuit because the matching has to be done nearby the infinite impedance area of the Smith Chart. In this paper, it is studied for the output matching circuit of the microwave oscillator to get the maximum output power. The maximum output point can be found by adjusting the position of moving short in the Tuner while the oscillator is operating after connect the 3-dB coupler Tuner to the oscillator without output matching circuit. To design the oscillator for the maximum output power can be done easily with the microstrip line which is realized from the measured S-parameters of Tuner. In compare the oscillator by the existing method with another one by the suggested method in this paper, the first one has 6.45 dBm output power and second one has 9.71 dBm which is 3.26 dBm higher than the first one at the oscillation frequency 1.0338 GHz.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.4
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• pp.44-53
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• 2011

This study designed and implemented a web-based computing environment for geovisual analytics using HTML5 canvas. The computing environment supports visualization tools and user's interaction. The visualization tools are cluster map, animated map, temporal parallel coordinate plot, and temporal heat map chart. Users can explore the temporal changes of cluster using multiple view and brushing technique. The computing environment that works well across browsers is used in the computing environment with multiple devices.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.1
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• pp.193-198
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• 2009

In this paper, we report the design of UHF RFID ceramic antenna using HFSS, one of the widely used RFID design tools. Of the developed antenna system, we analyze its Return Loss using HFSS and its characteristics using Smith Chart methodology. We built the ceramic antenna system based on the HFSS design, and analyzed its performance by measuring the impedence matching and gains using Network Analyzer. We attach the developed prototype to UHF RFID portable terminal, and performed distance measuring for five widely used types of RFID tags to verify the performance of our proposed antenna system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.5
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• pp.31-37
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• 2018

When an IoT system is constructed, a dashboard is also developed to monitor the values of sensors in the IoT System. Much time and money, however, are spent in developing the dashboard software. This paper presents design and implementation details of a dashboard maker called as YellowPeach, which helps to create a dashboard easily and fast without programming. Using YellowPeach, the user can author a dashboard by putting predefined charts to display values of sensors in it, and store the dashboard as a JSON file. Also an web application has been developed to run the dashboard on the web browser. The dashboard viewer web application connects on MQTT-based IoT system, receives values from the sensors, and displays the values on charts in real-time.

• The Journal of the Korea Contents Association
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• v.2 no.4
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• pp.17-22
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• 2002

This enable system integration for efficient data processing by interconnecting ASP and SQL, on-line consultation between patient and Korean medicine doctor, and semi-eternal use of medical examination data owing to storage and check of medical examination data(accurate medical examination and description using this medical examination data between patient and Korean medicine doctor). This is a Korean medicine remote examination system which converts from existing Korean medicine hospital system being maintained as existing off-line only to medical examination type of both on-line and off-line mode transcending time and space on web in which anyone can participate.

• The Journal of the Korea Contents Association
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• v.17 no.9
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• pp.32-38
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• 2017

In this study, we introduce a new way to improve the efficiency of Gait Analysis and promote its usage. This program can be shown in different points of view such as an individual or group patient data. The 'Gate Data Visualization Program' is improving its efficiency by minimizing the margin of error during research and promoting the easy interpretation. In addition, this program is designed to have an easy access, and can be used to develop the most basic medical equipment program to predict a probable disease for patient by collaborating with physicians specializing in neurosurgery.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.3
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• pp.121-126
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• 2019

Recently IoT named Internet of Things technology is widely used throughout the industry. In this paper, a smart vending machine system is proposed to solve inconvenience of vending machine which is commonly seen. This allows users to purchase goods without cash and saves management costs by allowing vending machine managers to stock and sell conveniently. For the production of this smart vending machine, Analysis example using UML which is object-oriented analysis method and flowchart and screen design applying it are presented. Also this presented method is shown to being applied usefully for a guideline of building smart vending machine commercialization system based on IoT.