• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.42-42
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• 2022

지금까지도 유역에서의 녹조 모니터링은 현장채수를 통한 점 단위 모니터링에 크게 의존하고 있어 기후, 유속, 수온조건 등에 따라 수체에 광범위하게 발생하는 녹조를 효율적으로 모니터링하고 대응하기에는 어려운 점들이 있어왔다. 또한, 그동안 제한된 관측 데이터로 인해 현장 측정된 실측 데이터 보다는 녹조와 관련이 높은 NDVI, FGAI, SEI 등의 파생적인 지수를 산정하여 원격탐사자료와 매핑하는 방식의 분석연구 등이 선행되었다. 본 연구는 녹조의 모니터링시 정확도와 효율성을 향상을 목표로 하여, 우선은 녹조 측정장비를 활용, 7000개 이상의 녹조 관측 데이터를 확보하였으며, 이를 바탕으로 동기간의 고해상도 위성 자료와 실측자료를 매핑하기 위해 다양한Machine Learning기법을 적용함으로써 그 효과성을 검토하고자 하였다. 연구대상지는 낙동강 내성천 상류에 위치한 영주댐 유역으로서 데이터 수집단계에서는 면단위 현장(in-situ) 관측을 위해 2020년 2~9월까지 4회에 걸쳐 7291개의 녹조를 측정하고, 동일 시간 및 공간의 Sentinel-2자료 중 Band 1~12까지 총 13개(Band 8은 8과 8A로 2개)의 분광특성자료를 추출하였다. 다음으로 Machine Learning 분석기법의 적용을 위해 algae_monitoring Python library를 구축하였다. 개발된 library는 1) Training Set과 Test Set의 구분을 위한 Data 준비단계, 2) Random Forest, Gradient Boosting Regression, XGBoosting 알고리즘 중 선택하여 적용할 수 있는 모델적용단계, 3) 모델적용결과를 확인하는 Performance test단계(R², MSE, MAE, RMSE, NSE, KGE 등), 4) 모델결과의 Visualization단계, 5) 선정된 모델을 활용 위성자료를 녹조값으로 변환하는 적용단계로 구분하여 영주댐뿐만 아니라 다양한 유역에 범용적으로 적용할 수 있도록 구성하였다. 본 연구의 사례에서는 Sentinel-2위성의 12개 밴드, 기상자료(대기온도, 구름비율) 총 14개자료를 활용하여 Machine Learning기법 중 Random Forest를 적용하였을 경우에, 전반적으로 가장 높은 적합도를 나타내었으며, 적용결과 Test Set을 기준으로 NSE(Nash Sutcliffe Efficiency)가 0.96(Training Set의 경우에는 0.99) 수준의 성능을 나타내어, 광역적인 위성자료와 충분히 확보된 현장실측 자료간의 데이터 학습을 통해서 조류 모니터링 분석의 효율성이 획기적으로 증대될 수 있음을 확인하였다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.11
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• pp.1-11
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• 2009

A content based pub/sub (Publish/subscribe) services at the peer-to-peer network has the requirements about how to distribute contents information of subscriber and to delivery the events efficiently. For satisfying the requirements, a DHT(Distributed Hash Table) based pub/sub overlay networking and tree type topology based network construction using filter technique have been proposed. The DHT based technique is suitable for topic based pub/sub service but it's not good contents based service that has the variable requirements. And also filter based tree topology networking is not efficient at the environment where the user requirements are distributed. In this paper we propose the R-Tree algorithm based pub/sub overlay network construction method. The proposed scheme provides cost effective event delivery method by mapping user requirement to multi-dimension and hierarchical grouping of the requirements. It is verified by simulation at the variable environment of user requirements and events.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.1
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• pp.1-7
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• 2016

Highly porous polymethyl methacrylate (PMMA) microspheres impregnated by $TiO_2$ powder were prepared by spray drying method. The particle size and the porosity were controlled by optimizing the co-solvent ratio and the polymer concentration. $TiO_2$ powder was impregnated into the microspheres upto 74.6 wt% content based on the weight of the resultant $PMMA/TiO_2$ microspheres. SEM images showed that $TiO_2$ powder was well distributed throughout the inside of the microsphere. EDX mapping showed that the Ti signal was well detected from every part of the microspheres, which was the evidence of the formation of the $PMMA/TiO_2$ composite. Hg porosimetry result showed that the porosity was found to be over 50% regardless of the $TiO_2$ contents. The final product was found to have high oil-absorbing capacity and great hiding power, both of which are key properties in designing the microsphere materials for make-up cosmetics application.

• Journal of Korean Library and Information Science Society
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• v.51 no.1
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• pp.1-20
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• 2020

This study is to find the methods that BIBFRAME could accept the new concept of representative expression in the RDA Toolkit Beta which has developed in 2019. Research methods were the literature reviews and the mapping between RDA Toolkit Beta and BIBFRAME. BIBFRAME's acceptance of representative expression of RDA Toolkit Beta was suggested as followings. First, the properties of representative expression should be defined in BIBFRAME because the RDA Toolkit Beta defined the expression attributes and representative expression elements apart. Three choices for BIBFRAME's acceptances are (1) to develop the newly devised representative expression properties (2) to specify representative expression properties with using refinement (3) to differentiate representative expression properties with using class. Second, as relationship elements should be defined in BIBFRAME to link work and representative expression which transfer the expression attribute to work. This study will contribute to revise the BIBFRAME because this focusd on BIBFRAME's acceptance of RDA Toolkit Beta in which reflected LRM.

• Journal of the Korea Society of Computer and Information
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• v.16 no.6
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• pp.79-88
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• 2011

In this paper, We propose real-time sound editing and playback systems which is based on Augmented Reality. The proposed system are composed with music maker which is based on AR maker and music board. By using music marker's contents, the proposed system selects the kinds of musical instruments and pre-defined midi track and by calculating the relative location of music marker on 2-dimensional plane, we set the spatial relative parameter in midi track. For performance evaluation, we check the jitter value of in various resolutions by using CAM which supports $1600{\pm}1200$ as the maximum resolution. As a result, when we set the configuration value of CAM as $860{\pm}600$ pixels and process two frames per minute, the success ratio of recognizing music markers and jitter values are accegnable. It can be utilized in the fields of alternative cmacine which is based on music and also be utilized in the educational aspects because child or elderly who don't know enough musical theory can easily handle it.

• Annual Conference on Human and Language Technology
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• 2006.10e
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• pp.189-196
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• 2006

본 논문은 시맨틱 웹 응용 서비스를 구현함에 있어 필수적으로 요구되는 온톨로지 인스턴스 구축을 효율적으로 처리하는 데 있어 텍스트 처리 기술이 어떤 역할을 수행할 수 있는 가를 $OntoFrame-K^{(R)}$라는 시맨틱 웹 기반 정보 유통 체계에의 적용 사례를 통해 살펴본다. 본 논문에서 소개하는 텍스트 처리 기술은 개체 확인물 통한 개념 사례화, 주제 분야 할당을 통한 메타데이터 확장에, 그리고 인용 정보 추출 및 인용 관계 구축을 통한 객체 관계속성 구축에 적용된다. 개체 확인에서는 메타데이터 비교 잊 병합을 사용하였으며 이를 기반으로 한 수작업 구축을 통해 8,543명의 인력 URI를 확보하였다. 주제 및 분야 할당에서는 색인어와 분야분류명이 매핑된 시소러스 개념어의 매칭을 통해 색인어 별 TF (Term Frequency), 색인어와 매칭된 개념어 별 TF, 색인어와 매칭된 개념어 별 시소러스에서의 깊이, 색인어와 매칭된 개념어 별 개념 패싯, 색인어와 매칭된 각 개념어에 부착된 분야분류명 목록 등 할당을 위한 다양한 자질을 확보 적용하였다. 인용 정보 추출과 인용 관계 구축에서는 객체 URI와 인력 URI를 기반으로 하여 자동 추출된 인용 정보를 반영하는 방식으로 7,237개 문헌으로부터 총 135개의 인용 네트워크 그룹을 자동으로 확보하였다. 본 연구를 통해 제시된 텍스트 처리 기술의 활용 방안이 향후 시맨틱 웹 응용 서비스 및 인프라 구현에서 다각적으로 활용될 수 있기를 기대한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.6
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• pp.652-662
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• 2016

This paper proposes a user mobility management scheme which supports seamless service even if a user changes his accessing terminal in service in IP-based convergence network. Most of ongoing researches concerning mobility management as well as the existing mobility schemes have been focused to support terminal mobility. It is limited to support a variety of mobility types such as user mobility. The proposed scheme uses the mapping relationship between UID(User Identifier), user specific identifier and TID(Terminal Identifier), specific terminal identifier and forms packet address with user specific permanent 3 layer address for session continuity in case of user mobility. We numerically analyze and compare handover signaling cost between the existing user mobility scheme and the proposed scheme. The result shows that the proposed scheme has lower handover signaling cost than the existing one, [1].

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.6
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• pp.522-528
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• 2009

This study focused on establishing prediction models using visible-near infrared spectrum to simultaneously detect multiple components of soils and enhancing the performance quality by suitably transformed input spectra and classification of soil spectral types for prediction model input. The continuum-removed spectra showed significant result for all cases in terms of soil properties and classified or bulk predictions. The prediction model using classified soil spectra at an absorption peak area around 500nm and 950nm efficiently indicating soil color showed slightly better performance. Especially, Ca and CEC were well estimated by the classified prediction model at $R^{2}$ > 0.8. For organic carbon, both classified and bulk prediction model had a good performance with $R^{2}$ > 0.8 and RPD> 2. This prediction model may be applied in global soil mapping, soil classification, and remote sensing data analysis.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.10
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• pp.551-557
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• 2016

Fusing satellite images and site-specific observations have potential to improve a predictive quality of environmental properties. However, the effect of the utilization of satellite images to predict soil properties in a wetland is still poorly understood. For the reason, block kriging and regression kriging were applied to a natural wetland, Water Conservation Area-2A in Florida, to compare the accuracy improvement of continuous models predicting total phosphorus in soils. Field observations were used to develop the soil total phosphorus prediction models. Additionally, the spectral data and derived indices from Landsat ETM+, which has 30 m spatial resolution, were used as independent variables for the regression kriging model. The block kriging model showed $R^2$ of 0.59 and the regression kriging model showed $R^2$ of 0.49. Although the block kriging performed better than the regession kriging, both models showed similar spatial patterns. Moreover, regression kriging utilizing a Landsat ETM+ image facilitated to capture unique and complex landscape features of the study area.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.2
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• pp.21-34
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• 2002

In this paper we propos a new hardware architecture of modular exponentiation using a division chain method which has been proposed in (2). Modular exponentiation using the division chain is performed by receding an exponent E as a mixed form of multiplication and addition with divisors d=2 or $d=2^I +1$ and respective remainders r. This calculates the modular exponentiation in about $1.4log_2$E multiplications on average which is much less iterations than $2log_2$E of conventional Binary Method. We designed a linear systolic array multiplier with pipelining and used a horizontal projection on its data dependence graph. So, for k-bit key, two k-bit data frames can be inputted simultaneously and two modular multipliers, each consisting of k/2+3 PE(Processing Element)s, can operate in parallel to accomplish 100% throughput. We propose a new encoding scheme to represent divisors and remainders of the division chain to keep regularity of the data path. When it is synthesized to ASIC using Samsung 0.5 um CMOS standard cell library, the critical path delay is 4.24ns, and resulting performance is estimated to be abort 140 Kbps for a 1024-bit data frame at 200Mhz clock In decryption process, the speed can be enhanced to 560kbps by using CRT(Chinese Remainder Theorem). Futhermore, to satisfy real time requirements we can choose small public exponent E, such as 3,17 or $2^{16} +1$, in encryption and verification process. in which case the performance can reach 7.3Mbps.