• Journal of Electrical Engineering and Technology
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• 제13권2호
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• pp.989-997
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• 2018

Massive event stream brings us great challenges in its volume, velocity, variety, value and veracity. Picking up some valuable information from it often faces with long detection time, high memory consumption and low detection efficiency. Aiming to solve the problems above, an efficient complex event detection method based on NFA_HTS (Nondeterministic Finite Automaton_Hash Table Structure) is proposed in this paper. The achievement of this paper lies that we successfully use NFA_HTS to realize the detection of complex event from massive RFID event stream. Specially, in our scheme, after using NFA to capture the related RFID primitive events, we use HTS to store and process the large matched results, as a result, our scheme can effectively solve the problems above existed in current methods by reducing lots of search, storage and computation operations on the basis of taking advantage of the quick classification and storage technologies of hash table structure. The simulation results show that our proposed NFA_HTS scheme in this paper outperforms some general processing methods in reducing detection time, lowering memory consumption and improving event throughput.

• 천문학회지
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• 제35권3호
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• pp.151-157
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• 2002

From the data of solar wind observation by ACE spacecraft orbiting the Earth-Sun Lagrangian point, we selected 48 forward interplanetary shocks(IPSs) occurred in 2000, maximum solar activity period. Examining the profiles of solar wind parameters, the IPSs are classified by their shock drivers. The significant shock drivers are the interplanetary coronal mass ejection(ICME) and the high speed stream(HSS). The IPSs driven by the ICMEs are classified into shocks driven by magnetic clouds and by ejectas based on the existence of magnetic flux rope structure and magnetic field strength. Some IPSs could be formed as the blast wave by the smaller energy and shorter duration of shock drivers such as type II radio burst. Out of selected 48 forward IPSs, $56.2\%$ of the IPSs are driven by ICME, $16.7\%$ by HSS, and $16.7\%$ of the shocks are classified into blast-wave type shocks. However, the shock drivers of remaining $10\%$ of the IPSs are unidentified. The classification of the IPSs by their driver is a first step toward investigating the critical magnitudes of the IPS drivers commencing the magnetic storms in each class.

• 한국지형학회지
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• 제28권4호
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• pp.1-13
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• 2021

In this study is aerial photos and UAV(Unmanned Aerial Vehicle) images were used to analyzed the characteristics of depositional landform changes in the Geum river channels before and after the opening gate of Gongju weir. Based on the depositional landform classification result, the main stream and the bare land occupied most of the area in all periods, and also found that the main stream, mid-channel island, and sand bar occupied a greater degree of area increase or decrease compared to other landforms in the classification items. As a result of analyzing the characteristics of depositional landform changes before and after the opening gate of Gongju weir, it is judged that the depositional landforms have changed due to the decreased water level of the Geum river after the opening of the weir, the summer rainy season and typhoons, river stabilization after the effluence of Daecheong dam, supply and deposition of river sediments and fixation of vegetation. The results derived from this study can be used as basic data for the study of river depositional landforms and the establishment of management and conservation plans for the landforms in river channels.

• 한국물환경학회지
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• 제37권4호
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• pp.249-262
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• 2021

This study investigated the pollution characteristics of the main pollution zone in the Hwangguji watershed and the influence of the tributary on the main stream. The characteristics of the main pollution zone, including, the water quality index (WQI), stream rating, load duration curve (LDC), delivery load density (DLD), and contribution of the tributary to the mainstream, were evaluated by time-series visual heatmap. The WQI of the mainstream of Hwangguji was lowered to the poor (IV) level from the inflow point of Suwon stream (SW) and the LDC excess rate in the T-P was higher than that of BOD₅, especially for the wet season, suggesting that management of non-point source with T-P is preferred. The contribution (%) of the tributaries in the upstream section of Hwangguji watershed were BOD₅ 14.54%, TOC 15.67%, T-N 5.43%, and T-P 6.97%. In particular, the Suwon sewage treatment plant located in the mainstream showed a high contribution of BOD₅ (64.40%) and T-P (53.54%), respectively, due to the high discharge rate (6.019 m³/sec). Meanwhile, Sammi and Gal stream have a large impact on the mainstream with high DLD and poor WQI. Thus, both streams were considered as pollution hot spots. These results provide useful basic data for preparing more effective water quality improvement and management plans in the watershed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권10호
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• pp.3378-3393
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• 2014

We have witnessed the rapid development of information technology in recent years. One of the key phenomena is the fast, near-exponential increase of data. Consequently, most of the traditional data classification methods fail to meet the dynamic and real-time demands of today's data processing and analyzing needs--especially for continuous data streams. This paper proposes an improved incremental learning algorithm for a large-scale data stream, which is based on SVM (Support Vector Machine) and is named DS-IILS. The DS-IILS takes the load condition of the entire system and the node performance into consideration to improve efficiency. The threshold of the distance to the optimal separating hyperplane is given in the DS-IILS algorithm. The samples of the history sample set and the incremental sample set that are within the scope of the threshold are all reserved. These reserved samples are treated as the training sample set. To design a more accurate classifier, the effects of the data volumes of the history sample set and the incremental sample set are handled by weighted processing. Finally, the algorithm is implemented in a cloud computing system and is applied to study user behaviors. The results of the experiment are provided and compared with other incremental learning algorithms. The results show that the DS-IILS can improve training efficiency and guarantee relatively high classification accuracy at the same time, which is consistent with the theoretical analysis.

• 한국지리정보학회지
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• 제2권3호
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• pp.60-70
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• 1999

GIS와 두시기의 Landsat TM영상을 이용하여 금호강 상류의 수질 오염인자에 대한 소유역별 공간분포의 변화를 탐지하고 수질측정지점에서 관측한 자료와 비교 분석하였다. 이를 위하여 수질오염원과 관련 있는 유역의 인자들을 ARC/INFO를 이용하여 데이터베이스를 구축하고, 1985년과 1997년의 위성영상을 이용하여 감독분류의 최우법으로 토지피복 분류도를 작성하였다. 아울러 두 시기의 토지이용변화 탐지 및 공간분석을 수행하여 소유역 분지별로 변화면적을 추출하였으며, 추출된 수질오염원의 변화량을 단계구분도로 작성하여 가중치를 부여하고 중첩분석을 실시하였다. 분석결과, 수질오염인자들 중에서 인구, 가축, 그리고 과수원 밭의 분포변화가 금호강 수질오염의 주요 요인임이 규명되었다. 금호강 상류에 있어서의 소유역별 오염원의 분포는 도시지역을 포함하고있는 대창천, 오목천 유역분지가 가장 높게 나타나고 있음이 본 연구에서 밝혀졌다.

• Current Research on Agriculture and Life Sciences
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• 제24권
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• pp.37-42
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• 2006

The purpose of this study was a biota research and analysis for Close-to-nature stream restoration planning of Shinchun. The summary of this study is as follows; 1) The vascular plants in research area recorded of 45 species and insect fauna recorded of 34 species of 8 orders. As a result of table of community classification, the communities were two group; Quercus variabilis community(I), Pinus densiflora-Quercus variabilis-Quercus dentata community(II). 2) As a result of analysis on correlation of tree species, the level of significance in positive correlation between Quercus dentata and Corylus heterophyll aindicated 1% and between Pinus densiflora and Lespedeza bicolor also indicated 1%. 3) As a result of DBH analysis, it is expected that Quercus variabilis and Quercus dentata will dominateover other species in competition and its succession continuously maintains from now on in community I. In community II, it is assumed that there is a high possibility of changing into community of Quercus such as Quercus mongolica, Quercus dentata, and Quercus variabilis. 4) As a result of analysis on insect fauna, insect fauna consists of 94% of whole species as 32 species, 23 families, 8 orders. And 7 species, 7 families 4 orders was found in highly urbanized area, the vicinity of Sang-Dong bridge. 5) As mentioned above, Based on A biota fundamental research, Close-to-nature stream restoration planning were full of suggestions: i) Designating ecosystem preservation area, ii) Making Close-to-nature stream revetments, iii) Making pool-and-riffle, vi) Making decks for observation and walks for nature experience, v) Creating wetland biotope. Through these methods, it is necessary to promote bio-diversity and lead people to the space for eco-learning.

• 한국도서관정보학회지
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• 제36권2호
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• pp.121-140
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• 2005

이 연구는 영미 양국과 국내의 공직 및 사서직제를 분석하고 시사점을 적출하는데 목적이 있다. 영미의 사례는 직제의 선진성과 시사점을, 그리고 국내의 직제분석은 그 후진성과 현주소를 파악하는데 유용할 뿐만 아니라 후속 연구과제인 사서직제 개선방안의 핵심논거로 활용될 수 있다. 한국의 사서직제가 문화선진국의 그것을 준용하는 방향으로 개편되기 위해서는 도서관 및 사서직에 내재된 이론적, 현실적 취약성과 한계를 극복하기 위한 논리를 개발해야 한다. 그리고 직제개선은 유연한 사고와 주체적 행위가 정합되어야 그 가능성도 높아진다.

• 한국컴퓨터정보학회논문지
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• 제13권1호
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• pp.37-44
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• 2008

데이터 스트림은 시간이 경과함에 따라서 데이터의 패턴이 변화하는 특성이 있다. 데이터 스트림에 내재되어 있는 이러한 특성 (컨셉트 변화)은 분류 모델의 예측 성능을 감소시킨다. CVFDT와 IOLIN은 점진적인 분류모델의 갱신을 통해 컨셉트 변화를 해결하고자 하였다. 그러나 이러한 방법들은 작은 패턴의 변화가 전체 분류 결과에 영향을 주는 지역적 컨셉트 변화를 식별하지 못함으로써 모델을 재 구축하는 단점이 있다. 본 논문은 컨셉트변화 발생 시 지역적 컨셉트 변화를 찾음으로써 시스템의 예측성능을 향상시키는 적응형 IOLIN을 제안한다. 실험 결과는 제안 기법인 적응형 IOLIN기법이 IOLIN기법에 비해 정확률에서 약 2.8%, CVFDT기법보다 약 11.2%정도 우수하였다.

• 한국환경보건학회지
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• 제20권4호
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• pp.17-35
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• 1994

This study was performed to investigate and assess the heavy metal contamination of sediment in main stream and tributaries of the Han-river in the vicinity of Seoul. Sediment were sampled at eight locations of main stream and eighteen locations of tributaries in the spring, summer, and fall in 1993. Six heavy metals of Cd, Cu, Pb, Zn, Cr, and Hg, were assessed. For an assessment of heavy metal contamination in sediment, the assessment method of Hakanson was modified to estimate for Han-river, then classification method of Muller in sediment quality was applied. For an assessment of contamination in each heavy metal, Contamination factor C$_f^i$ which was defined the ratio of concentration of i heavy metal in investigated location to background concentration of i heavy metal in uncontaminated upper area was used. The sediment quality in each heavymetal was classified as follows if C$_f^i$<1, Class I for Non contamination, if 1 < C$_f^i$ < 3, Class II for Low contamination, if 3< C$_f^i$ <6, Class III for Moderate contamination, if 6< C$_f^i$ <12, Class IV for Considerable contamination, and if C$_f^i$ > 12, Class V for High contamination.(abbreviation)