• Journal of Astronomy and Space Sciences
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• 제21권2호
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• pp.93-100
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• 2004

We have investigated characteristic solar wind dynamics associated with relativistic electron events at geosynchronous orbit. Most of the events for April, 1999 through December, 2002 are found to be accompanied by a prolonged solar quiet period which is characterized as low solar wind density, weak interplanetary magnetic field (IMF), and fast alfvenic fluctuations in IMF $B_z$. In a typical relativistic event, electron fluxes begin to increase by orders of magnitude when solar wind parameters drop to low values (e.g., $n_{sw}∼5 cm^{-3}$ and ｜$B_{IMF}$∼5 nT) after sharp peaks. Then the elevated electron fluxes stay at the high level during the solar quiet period. This observation may suggest the following scenario for the occurrence of a geosynchronous relativistic event: (ⅰ) Quiet solar winds can yield a stable and more dipole-like magnetospheric configurations in which the geosynchronous orbit locates well inside the trapping boundary of the energetic electrons. (ⅱ) If a large population of MeV electrons are generated (by whatever acceleration process(es)) in the inner magnetosphere, they can be trapped and effectively accumulated to a high intensity. (ⅲ) The high electron flux can persist for a number of days in the geosynchronous region as long as the solar wind dynamics stays quiet. Therefore the scenario indicates that the occurrence of a relativistic event would be a result of a delicate balance between the effects of electron acceleration and loss. In addition, the sensitive dependence of a relativistic event on the solar wind conditions makes the prediction of solar wind variability as important as understanding of electron acceleration processes in the forecast of a relativistic event.

• 산업기술연구
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• 제27권B호
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• pp.235-243
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• 2007

Sensor network is used to obtain sensing data in various area. The interval to sense the events depends on the type of target application and the amounts of data generated by sensor nodes are not constant. Many applications exploit long sensing interval to enhance the life time of network but there are specific applications that requires very short interval to obtain fine-grained, high-precision sensing data. If the number of nodes in the network is increased and the interval to sense data is shortened, the amounts of generated data are greatly increased and this leads to increased amount of packets to transfer to the network. To transfer large amount of packets fast, it is necessary that the delay between successive packet transmissions should be minimized as possible. In Sensor network, since the Operating Systems are worked on the event driven, the Timer Event is used to transfer packets successively. However, since the transferring time of packet completely is varies very much, it is very hard to set appropriate interval. The longer the interval, the higher the delay and the shorter the delay, the larger the fail of transfer request. In this paper, we propose ESTEO which reduces the delay between successive packet transmissions by using SendDone Event which informs that a packet transmission has been completed.In ESTEO, the delay between successive packet transmissions is shortened very much since the transmission of next packet starts at the time when the transmission of previous packet has completed, irrespective of the transmission timee. Therefore ESTEO could provide high packet transmission rate given large amount of packets.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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• pp.404-408
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• 1998

Yellow sand event has been studied using SeaWiFS data in order to examine the aerosol optical characteristics in the Yellow Sea and their influences on the atmospheric correction for the ocean color remote sensing. Two SeaWiFS images of April 18 and April 25, 1998, representing Yellow Sand event and clear-sky case respectively, are selected for emphasizing the impact of high aerosol concentration on the ocean color remote sensing. It was shown that NASA's standard atmospheric correction algorithm treats yellow sand area as either too high radiance or cloud area, in which ocean color information is not generated. SeaWiFS aerosol optical thickness is compared with nearby ground-based sun photometer measurements and also is compared with radiative transfer simulation in conjunction with yellow sand model, examining the performance of NASA's atmospheric correction algorithm in case of the heavy dust event.

• 한국식품영양과학회지
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• 제38권12호
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• pp.1794-1800
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• 2009

본 연구는 학교급식의 고객만족을 위한 이벤트 마케팅의 기초자료를 제공하고자 부산지역 초-중-고등학교의 영양사 359명을 대상으로 이벤트 마케팅 실시에 대한 중요도 및 수행도, 수행효과, 애로사항 및 개선필요사항 등을 조사하였다. 조사대상자의 근무유형은 초등학교 46.2%, 중학교30.4%, 고등학교 23.4%였으며, 급식소 운영형태는 직영이 76.1%, 위탁이 23.9%로 나타났다. 학교급식 이벤트 마케팅의 중요도와 수행도에 대한 IPA 분석 결과, 중요도는 5점만점에 평균 3.39점, 수행도는 평균 2.78점으로 중요하게 생각하는데 비해 수행도가 낮은 것으로 조사되었으며 중요하게 생각하여 잘 수행하고 있는 이벤트는 계절-명절-절기-환경-학교행사-기념일 이벤트로 나타났다. 초-중-고등학 교별로 살펴본 결과, 초-고등학교의 수행도가 중학교에 비해 유의적(p<0.01)으로 높았다. 특히 중요도는 초등학교에서는 절기, 고등학교에서는 경품과 홍보 이벤트가, 수행도는 초등학교에서는 명절과 절기, 고등학교에서는 세계요리-경품-홍보 이벤트가 유의적(p<0.01)으로 높았다. 운영형태별로 살펴본 결과, 직영 급식소에 비해 위탁 급식소의 수행도가 유의적(p<0.01)으로 높았으며, 특히 중요도는 위탁에서는 학교행사와 건강 이벤트가, 수행도는 직영에서는 절기, 위탁에서는 세계요리?경품?건강 이벤트가 유의적(p<0.01)으로 높았다. 이벤트 실시 효과는 고객만족도 증가와 신뢰도(노력하고 있음을 인정) 증가 순이었다. 이벤트 수행의 애로사항으로 내부요인은 부족한 인력, 예산의 어려움, 이벤트진행 전문성 순으로 나타났으며, 외부요인은 열악한 급식시설, 낮은 식단가, 급식형태의 순으로 조사되었다. 이벤트 수행을 위한 필요개선사항은 충분한 예산과 급식인력, 급식시설개선 순으로 조사되었다. 이상의 연구 결과에서, 학교급식 영양사들은 이벤트 마케팅 실시에 대해 중요하게 생각하는데 비해 수행도가 낮은 것으로 나타났는데, 학교급식에 대한 선택권이 부족한 학생고객들에 대한 배려와 서비스 제공에 적극 노력하고 외식의 기회가 빈번해짐에 따라 입맛이 다양화되고 고급화된 학생 고객군의 급식만족도를 높이기 위한 전략의 하나로 이벤트 실시에 대해 중요하게 생각하는 것에서 나아가 좀 더 적극적으로 이벤트 실시를 계획하여 수행하는 노력이 요구된다. 특히 초등학교에 비해 이벤트 마케팅 수행도가 낮게 나타난 중학교와 고등학교에서 좀 더 적극적이고 새롭고 다양한 이벤트 실시로 감수성이 예민한 청소년들의 호기심을 자극하고 학업으로 인한 스트레스를 해소하는 즐거움을 줌으로써 학생 고객들과의 관계지행성을 높여 급식만족도를 높일 수 있도록 해야 한다. 그러나 학교급식 고객인 학생들은 인원이 많은 단체급식의 식당에서 시행되는 이벤트에 대해서 호텔이나 패밀리레스토랑과 같은 전문성을 기대하기보다는 맛있고 다양한 메뉴의 음식을 배식원들로부터 친절하게 배식받기를 기대하므로 다수의 인력을 필요로 하거나 과도한 예산을 필요로 하는 이벤트와 같은 양적인 행사진행을 계획하여 고객들이 가장 중요하게 생각하는 부분을 놓치는 실수를 범하지 말고 다양하고 신선한 메뉴를 맛있게 조리하여 진심으로 환대하는 마음으로 서비스를 제공하는 질적으로 충실한 이벤트 계획에 힘쓰는 것이 필요하다고 생각된다.

• Nuclear Engineering and Technology
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• 제49권8호
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• pp.1589-1599
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• 2017

Field programmable gate arrays (FPGAs) are getting more attention in safety-related and safety-critical application development of nuclear power plant instrumentation and control systems. The high logic density and advancements in architectural features make static random access memory (SRAM)-based FPGAs suitable for complex design implementations. Devices deployed in the nuclear environment face radiation particle strike that causes transient and permanent failures. The major reasons for failures are total ionization dose effects, displacement damage dose effects, and single event effects. Different from the case of space applications, soft errors are the major concern in terrestrial applications. In this article, a review of radiation effects on FPGAs is presented, especially soft errors in SRAM-based FPGAs. Single event upset (SEU) shows a high probability of error in the dependable application development in FPGAs. This survey covers the main sources of radiation and its effects on FPGAs, with emphasis on SEUs as well as on the measurement of radiation upset sensitivity and irradiation experimental results at various facilities. This article also presents a comparison between the major SEU mitigation techniques in the configuration memory and user logics of SRAM-based FPGAs.

• 대한인간공학회지
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• 제22권1호
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• pp.81-94
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• 2003

The British railway safety research group has developed a risk assessment model for the railway infrastructure and major railway accidents. The major hazardous factors of the railway infrastructure were identified and classified in the model. The frequency rates of critical top events were predicted by the fault tree analysis method using failure data of the railway system components and ratings of railway maintenance experts, The consequences of critical top events were predicted by the event tree analysis method. They classified the Joss of accident due to railway system into personal. commercial and environmental damages. They also classified 110 hazardous event due to railway system into three categories. train accident. movement accident and non-movement accident. The risk assessment model of the British railway system has been designed to take full account of both the high frequency low consequence type events (events occurring routinely for which there is significant quantity of recorded data) and the low frequency high consequence events (events occurring rarely for which there is little recorded data). The results for each hazardous event were presented in terms of the frequency of occurrence (number of events/year) and the risk (number of equivalent fatalities per year).

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권8호
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• pp.4108-4122
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• 2019

Workflow process mining is becoming a more and more valuable activity in workflow-supported enterprises, and through which it is possible to achieve the high levels of qualitative business goals in terms of improving the effectiveness and efficiency of the workflow-supported information systems, increasing their operational performances, reducing their completion times with minimizing redundancy times, and saving their managerial costs. One of the critical challenges in the workflow process mining activity is to devise a reasonable approach to discover and recognize the bottleneck points of workflow process models from their enactment event histories. We have intuitively realized the fact that the iterative process pattern of redo-activities ought to have the high possibility of becoming a bottleneck point of a workflow process model. Hence, we, in this paper, propose an algorithmic approach and its implementation to discover the redo-activities and their performers' involvements patterns from workflow process enactment event logs. Additionally, we carry out a series of experimental analyses by applying the implemented algorithm to four datasets of workflow process enactment event logs released from the BPI Challenges. Finally, those discovered redo-activities and their performers' involvements patterns are visualized in a graphical form of information control nets as well as a tabular form of the involvement percentages, respectively.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.147-147
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• 2022

In January 2021 heavy flood affected South Kalimantan with causing many casualties. The heavy rainfall is predicted to be generated due to the ENSO (El Nino-Southern Oscillation). The weak La-Nina mode appeared to generate more convective cloud above the warmed ocean and result in extreme rainfall with high anomaly compared to past historical rainfall event. Subsequently, the antecedent soil moisture distribution showed to have an important role in generating the flood response. Saturated flow and infiltration excess mainly contributed to the runoff generation due to the high moisture capacity. The hydro-meteorological processes in this event were deeply analyzed using the coupled atmospheric model of Weather Research and Forecasting (WRF) and the hydrological model extension (WRF-Hydro). The sensitivity analysis of the flood response to the SST anomaly and the soil moisture capacity also compared. Result showed that although SST and soil moisture are the main contributors, soil moisture have more significant contribution to the runoff generation despite of anomaly rainfall occurred. Model performance was validated using the Global Precipitation Measurement (GPM) and Soil Moisture Operational Products System (SMOPS) and performed reasonably well. The model was able to capture the hydro-meteorological process of atmosphere and hydrological feedbacks in the extreme weather event.

• 한국정보통신학회논문지
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• 제12권1호
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• pp.205-214
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• 2008

수많은 센서 노드들을 이용하여 주변환경으로부터 정보를 수집하는 센서네트워크에서 많은 양의 패킷을 빠르게 전송하기 위해서는 패킷 전송간에 지연을 최소화하여 효율성을 높일 필요가 있다. 센서네트워크에서 이벤트에 기반하여 동작하는 운영 체제에서는 주로 주기적으로 발생하는 Timer Event를 이용하여 연속적으로 패킷을 전송한다. 하지만 무선 센서네트워크의 특성상 패킷을 전송하는데 소요되는 시간이 매우 가변적이기 때문에 적합한 주기를 설정하기가 매우 어렵다. Timer Event의 발생주기에 따라 패킷 전송간에 지연이 증가하거나 전송요청이 실패 할 수 있다. 본 논문에서는 패킷 전송 작업이 완료되었음을 알려 주는 SendDone Event를 이용하여 연속적인 패킷전송 시 지연을 줄여 주는 ESTEO기법을 제안한다. ESTEO에서는 패킷 전송이 완료된 시점에 즉시 다음 패킷을 전송하기 때문에 패킷을 전송하는데 소요되는 시간에 상관없이 패킷 전송간에 지연이 발생하지 않는다. 따라서 연속적으로 대량의 패킷을 전송할 때 높은 전송율을 제공할 수 있다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.1087-1094
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• 2010

With recent growth of population and industry, urban development grows into grand scheme of excavation and construction in urban area. As the development progress advanced, the developments get large and deepen. With a progress of technology development in geotechnical engineering in Korea, most our grand scheme of projects follows great progress. On the other hand, some excavation in construction site caused direct or indirect event that affects the adjacent or surrounding structures by excavation from time to time. This event usually happens around residential and commercial area where underground tunnel, subway station, commercial building, and high-rises excavation site is, could lead great damage on economy as well as personal injury or human casualties. In order to prevent this event, the study has to be done with analysis on various events of excavation and its cause. In this paper, the research has collected the various excavation events and their causes to analyze on each site and event to define emphasis on surrounding environment.