• Journal of Technology Innovation
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• v.28 no.3
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• pp.29-53
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• 2020

Existing main path analysis is useful to clarify the backbone of technology developments over the past, but has difficulty in identifying future technology candidates, and also in anticipating changes in the mainstream technology. Our method develops a growth velocity indicator, and combines it with key-route analysis and traversal counts measure in the main path analysis. It enables us to identify rapidly growing paths of future technology candidates, and further to evaluate the relative growth potential of such paths by which can replace the mainstream technology in the main path. Our method can contribute to identifying future technology candidates in a quantitative way by using patents, and broaden the scope of main path analysis research toward foresight. It can be useful for technology strategy in practice. Biofuel technology is exemplified.

• Journal of the Korea Society of Computer and Information
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• v.14 no.2
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• pp.111-118
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• 2009

Against Anomaly of GPS, there are several projects of independent satellite navigation systems like Galileo of Europe and QZSS of Japan and modernization of terrestrial navigation system like Loran. In domestic, the need of independent navigation system was proposed and DGPS signal was nominated as the possible substitute. The DGPS signal uses medium frequency, which travels through the surface and cause the additional delay rather than the speed of light according to Conductivities and elevations of the irregular terrain. The similar approach is Locan-C. Loran-C has been widely used as the maritime location system. Loran-C uses the ASF estimation method and provides more precise positioning. However there was rarely research on this area in Korea Therefore, we introduce the legacy guaranteed model of additional delay(ASF) and present the results of implementation. With the comparison of the original Monteath results and BALOR results respectively, we guarantee that the implementation is absolutely perfect. For further works, we're going to apply the ASF estimation model to Korean DGPS system with the Korean terrain data.

• Journal of Korea Water Resources Association
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• v.56 no.11
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• pp.729-735
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• 2023

The Moderate resolution Imaging Spectroradiometer (MODIS) is a multispectral sensor that has been actively researched in various fields using diverse land and atmospheric products. MODIS was first launched over 20 years ago, and the demand for novel sensors that can produce data comparable to that obtained using MODIS has continuously increased. In this study, land products obtained using the Visible Infrared Imaging Radiometer Suite (VIIRS) of the Suomi National Polar-orbiting Partnership (Suomi NPP) satellite launched in 2011 were introduced, including land surface temperature and vegetation indices such as the normalized difference vegetation index and enhanced vegetation index. These land products were compared with existing data obtained using MODIS to verify their local applicability in South Korea. Based on spatiotemporal monitoring of an extreme drought period in South Korea and the application of VIIRS land products, our results indicate that VIIRS can effectively replace MODIS multispectral sensors for agricultural drought monitoring.

• Journal of Internet Computing and Services
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• v.25 no.1
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• pp.69-78
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• 2024

Recently, consumers have shown an increasing tendency to seek information related to environmental, social, and governance (ESG) aspects in order to choose products with higher social value and environmental friendliness. In this paper, we proposes a product recommendation system applying ESG indicators tailored to the recent consumer trend of value-based consumption, utilizing a model called MultiSAGE that combines GraphSAGE and GAT. To achieve this, ESG rating data for 1,033 companies in 2022 collected from the Korea ESG Standard Institute and actual product data from N companies were transformed into a Heterogeneous Graph format through a data processing pipeline. The MultiSAGE model was then applied in machine learning to implement a recommendation system that, given a specific product, suggests eco-friendly alternatives. The implementation results indicate that consumers can easily compare and purchase products with ESG indicators applied, and it is anticipated that this system will be utilized in recommending products with social value and environmental friendliness.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.129-129
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• 2017

홍수파, 댐 및 보 등 하천구조물, 지류와 합류로 발생하는 배수영향 등으로 인해 고리형 수위-유량관계가 나타나 수위-유량관계식의 신뢰도가 저하된다고 판단되는 대하천 본류와 합류부 인근지류에서 초음파를 지표로 활용하는 자동유량장치가 현재 58개소에 도입되어 운용되고 있다. 그러나, 최근 다기능보 설치 등 하천의 수리적 특성이 변동하였고, 지류에서 주로 운용되는 수위-유량관계 기반 유량측정소에 본류-지류 합류로 인한 배수영향으로 고리형 관계가 형성될 경우, 지류수위관측소를 자동유량관측소로 대체할 필요성이 제기되고 있다. 또한, 기존 자동유량관측소의 경우도 홍수량이 기준이하로 나타날 경우 수위-유량 관계식으로 대체하는 경우도 발생하는데 적용기준이 명확하지 않은 경우가 많다. 본 연구에서는 신규 자동유량장치 설치, 기존 수위관측소 대체, 그리고 자동유량관측소에서 수위-유량 관계 활용 기준 설정 등을 판단하기 위해 고리형 수위-유량 관계의 패턴을 분석하여 지류의 수위관측소 존속여부 등을 결정할 수 있는 방법론을 제시하고자 한다. 이를 위해 다기능보 설치 및 지류-본류 합류로 인한 지류로의 배수영향과 홍수파에 의한 고리형 수위-유량관계의 양상을 다양한 수문사상에 대해 분석하였다. 시범구역으로 하류에 창녕함안보가 위치한 낙동강과 합류하는 남강을 대상하천으로 하였고 자동유량장치가 설치된 낙동강의 적포교, 남강의 정암관측소의 관측자료를 활용하여 HEC-RAS 부정류 모형을 구축하였다. 구축 후 다양한 본류와 지류의 유량을 가정하여 고리형 수위-유량 발생 패턴을 분석하였다. 지류-본류 합류 영향의 경우, 낙동강의 영향을 유무를 고려하여 상승된 수위의 비율로부터 일정 유의수준을 두어 배수영향 구간을 산정하였다. 다기능보 영향은 다기능보 설치 전후를 가정하여 영향을 분석하였다. 그 결과, 남강의 경우 지류 유량이 작은 경우에도 본류 유량이 상대적으로 큰 경우 배수영향에 의한 고리형이 나타났다. 그리고, 다기능보에의한 배수영향은 매우 작은 것으로 나타났고, 지류의 유량이 큰 경우 홍수파에 의한 고리형도 발생함을 알 수 있었으나, 지류-본류 합류로 인한 고리형 발생이 지배적이었다. 이러한 결과를 바탕으로 95%의 유의수준을 기반으로 고리형 발생 여부를 확인할 수 있는 모노그래프를 작성하여 수위-유량관계 기반 유량 산정의 적절성을 판단하는 기준으로 제안하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.05a
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• pp.504-507
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• 2020

ReLU(Rectified Linear Unit) 함수는 제안된 이후로 대부분의 깊은 인공신경망 모델들에서 표준 활성함수로써 지배적으로 사용되었다. 이후에 ReLU 를 대체하기 위해 Leaky ReLU, Swish, Mish 활성함수가 제시되었는데, 이들은 영상 분류 과업에서 기존 ReLU 함수 보다 향상된 성능을 보였다. 따라서 초해상화(Super Resolution) 과업에서도 ReLU 를 다른 활성함수들로 대체하여 성능 향상을 얻을 수 있는지 실험해볼 필요성을 느꼈다. 본 연구에서는 초해상화 과업에서 안정적인 성능을 보이는 EDSR(Enhanced Deep Super-Resolution Network) 모델의 활성함수들을 변경하면서 성능을 비교하였다. 결과적으로 EDSR 의 활성함수를 변경하면서 진행한 실험에서 해상도를 2 배로 변환하는 경우, 기존 활성함수인 ReLU 가 실험에 사용된 다른 활성함수들 보다 비슷하거나 높은 성능을 보였다. 하지만 해상도를 4 배로 변환하는 경우에서는 Leaky ReLU 와 Swish 함수가 기존 ReLU 함수대비 다소 향상된 성능을 보임을 확인하였다. 구체적으로 Leaky ReLU 를 사용했을 때 기존 ReLU 보다 영상의 품질을 정량적으로 평가할 수 있는 PSNR 과 SSIM 평가지표가 평균 0.06%, 0.05%, Swish 를 사용했을 때는 평균 0.06%, 0.03%의 성능 향상을 확인할 수 있었다. 4 배의 해상도를 높이는 초해상화의 경우, Leaky ReLU 와 Swish 가 ReLU 대비 향상된 성능을 보였기 때문에 향후 연구에서는 다른 초해상화 모델에서도 성능 향상을 위해 활성함수를 Leaky ReLU 나 Swish 로 대체하는 비교실험을 수행하는 것도 필요하다고 판단된다.

• Journal of the Korean Geographical Society
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• v.40 no.2 s.107
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• pp.221-241
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• 2005

Land Use and Land Cover Changes (LUCC) occur over a wide range of space and time scales, and involve complex natural, socio-economic, and institutional processes. Therefore, modelling and predicting LUCC demands an understanding of how various measured properties behave when considered at different scales. Understanding spatial and temporal variability of driving forces and constraints on LUCC is central to understanding the scaling issues. This paper aims to 1) assess the heterogeneity of land cover change processes over the landscape in northern Ghana, where intensification of agricultural activities has been the dominant land cover change process during the past 15 years, 2) characterise dominant land cover change mechanisms for various spatial scales, and 3) identify the optimal spatial scale for LUCC modelling in a savanna landscape. A multivariate statistical method was first applied to identify land cover change intensity (LCCI), using four time-sequenced NDVI images derived from LANDSAT scenes. Three proxy land use change predictors: distance from roads, distance from surface water bodies, and a terrain characterisation index, were regressed against the LCCI using a multi-scale hierarchical adaptive model to identify scale dependency and spatial heterogeneity of LUCC processes. High spatial associations between the LCCI and land use change predictors were mostly limited to moving windows smaller than 10$\times$10km. With increasing window size, LUCC processes within the window tend to be too diverse to establish clear trends, because changes in one part of the window are compensated elsewhere. This results in a reduced correlation between LCCI and land use change predictors at a coarser spatial extent. The spatial coverage of 5-l0km is incidentally equivalent to a village or community area in the study region. In order to reduce spatial variability of land use change processes for regional or national level LUCC modelling, we suggest that the village level is the optimal spatial investigation unit in this savanna landscape.

• Journal of Korean Society of Disaster and Security
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• v.14 no.4
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• pp.69-80
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• 2021

This study tried to suggest improvement measures by discovering problems or matters requiring improvement among the annual regional safety evaluation systems. Briefly introducing the structure and contents of the study, which is the introduction, describes the regional safety evaluation method newly applied by the Ministry of Public Administration and Security in 2020. Utilization plans were also introduced according to the local safety level that was finally evaluated by the local government. In this paper, various views of previous researchers related to regional safety are summarized and described. In addition, problems were drawn in the composition of the index of local safety, the method of calculating the index, and the application of the current index. Next, the problems of specific regional safety evaluation indicators were analyzed and solutions were presented. First, "Number of semi-basement households" is replaced with "Number of households receiving basic livelihood" of 「Social Vulnerability Index」 in the field of disaster risk factors is replaced with "the number of households receiving basic livelihood". In addition, the "Vinyl House Area" is evaluated by replacing "the number of households living in a Vinyl House, the number of container households, and the number of households in Jjok-bang villages" with data. Second, in the management and evaluation of habitual drought disaster areas, local governments with a water supply rate of 95% or higher in Counties, Cities, and Districts are treated as "missing". This is because drought disasters rarely occur in the metropolitan area and local governments that have undergone urbanization. Third, the activities of safety sheriffs, safety monitor volunteers, and disaster safety silver monitoring groups along with the local autonomous prevention foundation are added to the evaluation of the evaluation index of 「Regional Autonomous Prevention Foundation Activation」 in the field of response to disaster prevention measures. However, since the name of the local autonomous disaster prevention organization may be different for each local government, if it is an autonomous disaster prevention organization organized and active for disaster prevention, it would be appropriate to evaluate the results by summing up all of its activities. Fourth, among the Scorecard evaluation items, which is a safe city evaluation tool used by the United Nations Office for Disaster Risk Reduction(UNDRR), the item "preservation of natural buffers to strengthen the protection functions provided by natural ecosystems" is borrowed, which is closely related to natural disasters. The Scorecard evaluation is an assessment index that focuses on improving the disaster resilience of local governments while carrying out the campaign "Creating cities resilient to climate crises and disasters" emphasized by UNDRR. Finally, the names of "regional safety level" and "local safety index" are similar, so the term of local safety level is changed to "natural disaster safety level" or "natural calamity safety level". This is because only the general public can distinguish the local safety level from the local safety index.

• Korean Journal of Remote Sensing
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• v.29 no.5
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• pp.443-459
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• 2013

Located on Java subduction zone, Merapi volcano is an active stratovolcano with a volcanic activity cycle of 1-5 years. Merapi's eruptions were relatively small with VEI 1-3. However, the most recent eruption occurred in 2010 was quite violent with VEI 4 and 386 people were killed. In this study, we have attempted to study the characteristics of Merapi's eruptions during 18 years using optical Landsat images. We have collected a total of 55 Landsat images acquired from July 6, 1994 to September 1, 2012 to identify pyroclastic flows and their temporal changes from false color images. To extract areal extents of pyroclastic flows, we have performed supervised classification after atmospheric correction by using COST model. As a result, the extracted dimensions of pyroclastic flows are nearly identical to the CVP monthly reports. We have converted the thermal band of Landsat TM and ETM+ to the surface temperature using NASA empirical formula and calculated time-series of the mean surface temperature in the area of peak temperature surrounding the crater. The mean surface temperature around the crater repeatedly showed the tendency to rapidly rise before eruptions and cool down after eruptions. Although Landsat satellite images had some limitations due to weather conditions, these images were useful tool to observe the precursor changes in surface temperature before eruptions and map the pyroclastic flow deposits after eruptions at Merapi volcano.

• Journal of Nutrition and Health
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• v.40 no.5
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• pp.428-434
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• 2007

Cham-dang-gui (Angelica gigas nakai) has been used in traditional Korean medicine to treat hemotological disorders. The purpose of this study is to investigate the hematological effects of water extracts of Cham-dang-gui in rats with anemia induced by iron-free diets. Rats were divided into two groups, a regular diet group (RD) and an iron-free diet group (FeD). The iron-free diet group was then subdivided into the following three treatment groups: saline (1.0 ml/kgBW/day, FeDS), Cham-dang-gui (1.0 g/kgBW/day, FeDA), and iron (iron succinylate 14 mg/kgBW/day, FeDFe) groups. Rats were fed an iron-free diet for 6 weeks to induce iron-deficient anemia, and subsequently underwent the treatments, during which they were fed an iron-free diet for 3 weeks followed by a regular diet for 3 weeks. Body weights of the iron-diet groups (FeDS, FeDA, FeDFe) were lower than that of RD group. The blood levels of Hgb, Hct, MCV, MCH and TIBC were significantly higher in RD and FeDFe groups than those of other groups. The water extract of Cham-dang-gui with iron-free diet has no hematological effects. A regular diet followed by iron-free diets significantly increased blood levels of Hgb, Hct, and MCH.