• Journal of Korea Water Resources Association
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• v.30 no.3
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• pp.269-278
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• 1997

Operating rules, the basic principle of reservoir operation, are mostly developed from maximum or minimum, mean inflow series so that those rules cannot be used in practical operating situations to estimate the expected benefits or provide the operating policies for uncertainty conditions. Many operating rules based on the deterministic method that considers all operation variables including inflows as known variables can not reflect to uncertainties of inflow variations. Explicit operating rules can be developed for improving the weakness. In this method, stochastic trend of inflow series, one of the reservoir operation variables, can be directly method, the stochastic technique was applied to develop reservoir operating rule. In this study, stochastic dynamic programming using the concepts was applied to develop optimal operating rule for the Chungju reservoir system. The developed operating rules are regarded as a practical usage because the operating policy is following up the basic concept of Lag-1 Markov except for flood season. This method can provide reservoir operating rule using the previous stage's inflow and the current stage's beginning storage when the current stage's inflow cannot be predicted properly.

• Journal of the Korean Society for information Management
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• v.37 no.2
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• pp.171-195
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• 2020

This study analyzed the collaborative process in time series by dismantling the edit log big data of Wikipedia Korea, a representative online collaboration community, from early 2002 to 2019. Analysis elements were extracted from the document edit records, formatted in standardized XML, and analyzed using Python and R. The ways of editors' contribution, the characteristics of data contents, and the trend of document creation were explained by the analysis. An active contribution of a small set of editors and a loose participation of the majority were revealed. In addition, sociocultural characteristics that appear in online communities were also found in Wikipedia Korea. A new, diverse set of external resources is necessary to sustain the collective intelligence. An effort to settle new editors into the wikipedia community and an openness through circulation structure to avoid the exclusiveness of the management group are suggested.

• 한국HCI학회:학술대회논문집
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• 2007.02b
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• pp.7-14
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• 2007

디지털 컨버전스가 가속화됨에 따라 휴대폰의 기능은 나날이 복잡해져 가고 있으며, 이러한 경향은 사람들에게 자신에게 불필요한 기능까지 익혀야 하는 불편함을 초래하고 있다, 특히, 단순한 통화방식에 익숙하고 인지적으로 새로운 것을 유연하게 받아들이지 못하는 고령 사용자들에게도 이미 생활필수품이 된 휴대폰은 사용하는데 어렵고 불편한 부분이 많이 있다. 본 연구에서는 한국의 고령사용자들을 대상으로 휴대폰 사용에 있어 문맥적, 정성적 조사(Contextual & Qualitative research)기법을 적용하여 평소 그들이 일상생활에서 느끼는 휴대폰 관련 요구사항을 도출하고자 하였다. 조사는 세 단계로 이루어졌다. 먼저, 휴대폰을 사용 중인 60대 이상 고령사용자 83명을 대상으로 사용 현황 및 수준을 파악하고 적절한 사용자를 섭외하기 위한 설문을 진행하였으며, 둘째, 초보사용자 8명, 중급사용자 3명을 대상으로 휴대폰 사용 기록을 기반으로 하는 심층인터뷰를 진행하였으며, 초보사용자들을 대상으로는 문자메세지, 전화번호부, 카메라 폰 기능 교육 세션을 통한 행동 관찰법을 시행하였다. 마지막으로, 교육 세션 한달 후, 사용성 평가와 추가 인터뷰를 진행하였다. 이상과 같이 장기간에 걸친 사용자 조사를 통해, 고령사용자들의 휴대폰 사용에 있어 심리, 문화적 특이사항과 인터랙션 상의 불편요소들을 발견할 수 있었으며, 수집된 동영상 데이터를 분석하여 고령사용자의 휴대폰 관련 요구사항을 신체적 요인, 인지적요인, 심리적 요인의 세가지로 구분하여 제시하였다. 본 연구에서는 문맥적, 정성적 사용자 조사를 통해 고령사용자들의 일상생활에서의 휴대폰 관련 요구사항을 도출함으로써 풍부하고 실증적인 경험데이터를 수집할 수 있었다. 이와 같이 도출된 요구사항 데이터는 이후 고령사용자를 위한 유니버설 디자인 휴대폰 개발 전략수립과 UI 디자인 개발에 활용되었다. 뿐만 아니라, 이 연구는 휴대폰 사용 경험 연구에 적용할 수 있는 문맥적 조사기법 프로세스의 사례를 제시하고 있다는데 의의가 있다고 하겠다.

• Journal of the Korean School Mathematics Society
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• v.15 no.1
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• pp.53-80
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• 2012

This study was designed to find the characteristics of mathematical errors and discourse in simultaneous equations and inequalities for migrant students from North Korea. 5 sample students participated, who attended in an alternative school for the migrant students from North Korea at the study in Seoul, Korea. A total of 8 lesson units were performed as an extra curriculum activity once a week during the 1st semester, 2011. The results indicated that students showed technical errors, encoding errors, misunderstood symbols, misinterpreted language, and misunderstood Chines characters of Koreans and the discourse levels improved from the zero level to the third level, but the scenes of the third level did not constantly happen. Nevertheless, the components of discourse, explanation & justification, were activated and as a result, evaluation & elaboration increased in ERE pattern on communication.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.3
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• pp.35-42
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• 2012

The database for driving patterns can be utilized in various system such as automatic driving system, driver safety system, and it can be helpful to monitor driving style. Therefore, we propose a driving pattern recognition system in which the sensor streams from a smartphone are recorded and used for recognizing driving events. In this paper we focus on the driving pattern recognition that is an essential and preliminary step of driving style recognition. We divide input sensor streams into 7 driving patterns such as, Left-turn(L), U-turn(U), Right-turn(R), Rapid-Braking(RB), Quick-Start(QS), Rapid-Acceleration (RA), Speed-Bump(SB). To classify driving patterns, first, a preprocessing step for data smoothing is followed by an event detection step. Last the detected events are classified by DTW(Dynamic Time Warping) algorithm. For assisting drivers we provide the classified pattern with the corresponding video stream which is recorded with its sensor stream. The proposed system will play an essential role in the safety driving system or driving monitoring system.

• Journal of Korean Society for Geospatial Information Science
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• v.19 no.4
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• pp.3-12
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• 2011

Understanding of water sediment trends is an important part of water quality monitoring. Water quality variables change over time and space, and cannot be modeled or explained clearly by either temporal or spatial analysis alone. This research analysed the trends of temperature, pH levels and dissolved oxygen levels based on the sediment records and spatial data obtained in Lower Mekong Basin (LMB) during 1985-2005. Our aim is to evaluate spatio-temporal trends and graphical analyses using an Inverse Distance Weighting (IDW) interpolation method. The main results from this research can be summarized as follows. The maximum temperature and pH have been stable during the study period and the maximum dissolved oxygen has been increasing gradually until 2002. The minimum pH and dissolved oxygen have been changing in an unsteady trend during the period. A spatial analysis shows that the water temperature in this region has been increasing over time. The pH trend shows that it is decreasing during 1993-2005. Dissolved oxygen concentration has been increasing from 1989 onwards and stays in that track.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.827-830
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• 2013

Due to strong wind of smartphone, change in human life is facing 21 Century's new revolution. The end of 2012, The record rate of supply of smartphone is up to 58.8 percent. So the reputation of IT power are continuing. Korea is boasting IT infrastructure, and the reputation of IT power with rapidly evolving. But Korea is one of OECD country with the longest working hours and in labor productivity, yet is located in the lower rank. Now, common social issues such as low-carbon, green growth, low birthrate, graying, labor productivity growth, the reduce greenhouse gas is constantly increasing in worldwide. So Smart Work is getting attention as a way to resolve this. In this paper, we study the impact of small business on local economy and the status information of small business on statistical point of view. And we offer the smart work countermeasures of small business through detailed action elements and the model proposed fot driving factor for the promotion of smart work. Through this, we propose the IT system model for The SMEs-type smart work system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.1977-1985
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• 2009

An e-Seal is an active RFID device that was set on the door of a container. e-Seal provides both the state of the seal and the remote control of the device automatically. But it has vulnerabilities like eavesdrop and impersonate because of using RFID system. A secure e-Seal authentication protocol must use PRF for encryption/decryption of reader and e-Seal. The existing PRF uses simple hash function such as MD5 or SHA which is not available for e-Seal. It is required to use strong hash functions. The hash function is a essential technique used for data integrity, message authentication and encryption in the mechanism of information security. Therefore, in this paper, we propose more secure and effective hash function based on polynomial for e-Seal authentication protocol.

• Journal of the Korean Geophysical Society
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• v.4 no.1
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• pp.21-33
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• 2001

Simultaneous inversion of first-arrivals of local earthquakes recorded by the Korea Meteorological Administration(KMA) seismograph network from 1991 to 1998 is made to derive 1D crustal velocity structure of the Korean peninsula. Twenty-nine events with 178 observations are used in the inversion. Average crustal P-wave velocity turns out to be about 6.3 km/sec, and crustal thickness and upper mantle P-wave velocity are estimated as 33 km and 7.9 km/sec, respectively. Results of inversion indicate the possibility of the low velocity layer in the lower crust. Joint inversion is applied to estimate hypocenters, station delays, and velocities simultaneously. Relative station corrections for 11 stations range from zero to about 1.2 sec. Analysis of the synthetic data shows that estimates of hypocenter locations and station corrections as well as averaged crustal structure are reliable for the given data set..

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.3
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• pp.547-554
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• 2022

Recently, the field of telemedicine is growing rapidly due to the COVID-19 pandemic. However, the cost of telemedicine services is relatively high, since cloud computing, video conferencing, and cyber security should be considered. Therefore, in this paper, we design and implement a cost-effective P2P-based telemedicine system. It is implemented using the widely used the open source computing platform, Raspberry Pi, and P2P network that frees users from security problems such as the privacy leakage by the central server and DDoS attacks resulting from the server/client architecture and enables trustworthy identifying connection system using SSL protocol. Also it enables users to check the other party's status including body temperature in real time by installing a thermal imaging camera using Raspberry Pi. This allows several medical diagnoses that requires visual aids. The proposed telemedicine system will popularize telemedicine service and meet the ever-increasing demand for telemedicine.