• Journal of Fisheries and Marine Sciences Education
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• v.28 no.2
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• pp.376-383
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• 2016

In this paper, the blue-green algae monitoring program of applying IoT(Internet of things) technologies is designed and implemented that can check out the status of the river's water quality in real time. The proposed system is to extract the image data from the camera of raspberry pi by an wireless network, and it is analyzed through the HSV color model. We measure the temperature using a DS18B20 1-wire temperature sensor. The extracted information of image data and temperature is then analyzed in C and Python programs for use with Raspberry Pi. The XML data in PHP program is made from the analyzed information and provides Web services. It also allows to refer the XML data using mobile devices.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.553-555
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• 2013

본 논문은 HTML5의 새로운 표준인 웹소켓(WebSocket)을 이용하여 구현한 실시간 커뮤니케이션 시스템을 소개한다. 본 논문에서 구현한 시스템은 PC의 브라우저와 모바일 디바이스 모두를 통해 접근이 가능하다. 본 논문에서 구현한 실시간 커뮤니케이션 서비스 시스템은 이벤트 기반의 비동기 방식을 채택함으로써, 클라이언트가 리로드(reload)하지 않더라도 필요한 정보를 빠르게 제공한다. PC의 브라우저가 접근하는 부분은 Node.js를 사용하여 구현하였으며, 모바일 디바이스가 접근하는 부분은 PhoneGap 플랫폼을 사용하여 구현하였다. 본 논문에서는 시스템의 전체 구조와 관련 기술을 설명하고, 구체적인 구현 코드의 일부를 제시하며, 추후 확장 가능성과 비전을 제시한다.

• Korean Journal of Remote Sensing
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• v.27 no.2
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• pp.203-211
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• 2011

Recently, information communication technologies such as smartphone or mobile app greatly affect various application fields including geo-spatial domain. And development scheme of mobile web app or hybrid app regards as the most important computing technology which is combined each advantage of mobile app and mobile web. Despite these trends, it is general case that satellite images are used for the background image for other contents services. With this motivation, hybrid app for geo-metadata as the base for dissemination and service is designed and implemented as the prototype, in this study. At the design stage, HTML5, which is the core technology on an international standardization process for hybrid app, is applied. In the implementation, PhoneGap and Sencha Touch as mobile SDK(Software Development Kit) supporting HTML5 on cross-platform in open sources are used. In prototype, some KOMPSAT-2 images covering small area and mandatory elements in geo-metafata standard are tested. As mobile industry applications and business service models based on satellite images on mobile platform are progressing and diversifying, it is expected that this approach and implemented prototype are considered as an important reference.

• Journal of Korea Society of Industrial Information Systems
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• v.18 no.2
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• pp.59-69
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• 2013

By the end of 2012, there were 5.1 billion mobile communication subscribers in South Korea. The majority of subscriptions (97.3 percent) were for mobile phones, particularly smartphones. From 2010 to 2012, the number of mobile phone subscriptions increased 2,000 percent, growing from an initial subscriber base of 150 million. This paper explores the changing mobile communication landscape from a socio-technological perspective to understand the underlying drivers of change and their effects on the South Korean populace. A content analysis of 11,156 electronic newspaper articles mentioning mobile communication in South Korea and occurring between 2010 and 2012 was conducted. 5,119 keywords were extracted based on frequency statistics and further analyzed to determine the drivers of change. Based on this analysis, we conclude that South Korea's mobile communication environment is focused on rapid expansion of technology with minor consideration given to the social aspects of this change. This has resulted in several negative consequences and we urge for new policies by government and industry to address this gap.

• Journal of the Ergonomics Society of Korea
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• v.26 no.2
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• pp.149-155
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• 2007

Recently, various devices requiring text input such as mobile phone IPTV, PDA and UMPC are emerging. The frequency of text entry for them is also increasing. This study was focused on the evaluation of Korean text entry interface. Various models to evaluate text entry interfaces have been proposed. Most of models were based on human cognitive process for text input. The cognitive process was divided into two components; visual scanning process and finger movement process. The time spent for visual scanning process was modeled as Hick-Hyman law, while the time for finger movement was determined as Fitts' law. There are three questions on the model-based evaluation of text entry interface. Firstly, are human cognitive processes (visual scanning and finger movement) during the entry of text sequentially occurring as the models. Secondly, is it possible to predict real text input time by previous models. Thirdly, does the human cognitive process for text input vary according to users' text entry speed. There was time gap between the real measured text input time and predicted time. The time gap was larger in the case of participants with high speed to enter text. The reason was found out investigating Eye-Hand Coordination during text input process. Differently from an assumption that visual scan on the keyboard is followed by a finger movement, the experienced group performed both visual scanning and finger movement simultaneously. Arrival Lead Time was investigated to measure the extent of time overlapping between two processes. 'Arrival Lead Time' is the interval between the eye fixation on the target button and the button click. In addition to the arrival lead time, it was revealed that the experienced group uses the less number of fixations during text entry than the novice group. This result will contribute to the improvement of evaluation model for text entry interface.

• Journal of Digital Convergence
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• v.13 no.10
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• pp.501-508
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• 2015

This study intends to look into the perception gap among Korean and Chinese consumers regarding the product attitudes toward smart phones and repurchase intention as well as the user experience. First, this study showed that there are gaps among Korean and Chinese consumers, regarding smart phones, toward their experiences of usage satisfaction, usefulness, design satisfaction, and evaluation from other people and that Chinese consumers have higher awareness of every experience element concerning UI than Korean consumers. Second, concerning the difference in the product attitudes toward smart phones, it turns out that Chinese consumers also have higher awareness of it than Korean consumers. Third, regarding the difference in repurchase intention for smart phones among Korean and Chinese consumers, this study shows that Chinese consumers are likely to have more intention than Korean consumers. because their average value is higher than Korean consumers' even though the difference are not statistically significant. This study is expected to have academic meaning(significance) for providing basic materials of comparative study between two countries regarding the user experience about smart phone as well as some useful implications for the competitive power improvement of Korean smart phone related companies in China.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.3 s.168
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• pp.46-51
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• 2005

The vacuum cleaner motor runs at very high speed for suction power. Specially, motor power is provided by the impeller being rotated at very high speed. The centrifugal fan consists of the impeller, the diffuser, and the circular casing. Due to the high rotating speed of the impeller and small gap distance between the impeller and the diffuser, the level of noise in the centrifugal fan is at BPF(Blade Passage Frequency) and its harmonic frequencies. In order to calculate the sound pressure of centrifugal fan, unsteady flow data are needed. The cause of noise is obtained by dividing the fluid noise by exhaust flow of fan and vibration noise by rotational vibration of vacuum cleaner fan motor. Until now, an accelerometer has been used to measure vibration. However, it can not measure vibration in some parts of brush and commutator because of motor construction and 3-D vibrating mode. This study was conducted to perform accurate analysis of vibration and aerodynamic sound for fan motor in a vacuum cleaner using a laser vibration analyzer. A silent fan motor can be designed using the data measured in this study.

• Journal of KIISE:Databases
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• v.35 no.5
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• pp.400-410
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• 2008

Flash memory has been widely used in mobile devices, such as mobile phone and digital camera. Recently flash SSD(Solid State Disk), having same interface of the disk drive, is replacing the hard disk of some laptop computers. However, flash memory still cannot be considered as the storage of database systems. The FTL(Flash Translation Layer) of commercial flash SSD, making flash memory operate exactly same as a hard disk, shows poor performance on the workload of databases with many random overwrites. Recently In-Page Logging(IPL) approach was proposed to solve this problem. In this paper, we implement IPL approach on SQLite, a popular open source embedded DBMS, and evaluate its performance. It improves the performance by up to 30 factors for update queries.

• Journal of Digital Contents Society
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• v.14 no.2
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• pp.235-245
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• 2013

Recent national attention on English conversation continued, smartphone game has emerged into the mainstream of game industry. In this study, smartphone serious game that combines english conversation learning and smartphone game for learning english conversation was designed and implemented. English sentence patterns separated words, phrases, and sentences was able to learn step-by-step and repeatedly. Also, Throughout the game of different type by stage was to provide interested. Test results were discovered the problem not causing continuous user interest. To compensate for this, study of a game changes element and difficulty adjusting will be followed.

• Journal of IKEEE
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• v.23 no.2
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• pp.747-750
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• 2019

Wearable devices have become practically indispensable to daily life and helped people track and manage fitness, health, and medical functions etc. As these wearable devices become smaller and more comfortable for the user, the demand for longer run time and charging ways presents new challenges for the power management engineer. Wireless power transfer (WPT) is the technology that forces the power to transmit electromagnetic field to an electrical load through an air gap without interconnecting wires. This technology is widely used for the applications from low power smart phone to high power electric railroad and main electrical grid. There are two kinds of WPT methods: Inductive coupling and magnetic resonant coupling. The model using magnetic resonant coupling method is designed for a resonant frequency of 13.45 MHz. In this study, the hardware implementations of these two coupling methods are carried out, and the efficiencies are compared.