• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.244-244
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• 2017

2015년 국토교통부(영산강홍수통제소)에서는 물 순환 과정의 규명에 이용되는 증발산량 자료의 제공을 목적으로 무안지역에 플럭스 타워를 설치하여 운영하고 있다. 무안 플럭스 타워는 에디공분산 방법을 이용하여 증발산량 자료를 관측하는 방식으로, 본 연구에서는 무안 관측소에서 생산된 자료의 정상성 검토를 위하여 2015년과 2016년 운영 결과를 비교 분석하였다. 무안관측소의 2015년도 연 증발산량은 615.8mm(연 강수량 대비 56.0%)로 나타났으며, 2016년도 연 증발산량은 721.5mm(연 강수량 대비 49.5%)로 나타났다. 연 증발산량은 전년대비 약 100mm 증가하는 양상을 보였으며, 강수량 대비 비율은 6.5% 감소하는 것으로 분석되었다. 2015년 대비 2016년 무강우일수는 6일 증가 하였으나, 실제 순복사에너지는 $18,320w/m^2$ 감소하는 것으로 나타났다. 실제 이 차이는 2개년 평균치의 약 2% 내외 수준으로 예년대비 순복사에너지는 거의 비슷한 것으로 분석되었다. 복합적 요인에 의해 정량적 크기가 결정되는 증발산량의 특성상 추가적인 분석이 필요하나, 2016년의 경우 전년대비 증가한 강우의 영향이 지배적이였던 것으로 검토되었다(2015강수량 : 1,099mm, 2016강수량 : 1,457mm). 월별 증발산량 비교 분석결과 정량적인 차이는 존재했으나 전년과 마찬가지로 1월부터 증발산량이 증가하여 8월에 최대 증발산량을 보인 후 감소하는 형태를 나타냈으며, 5월과 6월이 증발산량이 역전되는 양상도 동일하게 나타났다. 이는 남부지역 모내기 시기인 5월경 관개용수(Irrigation water) 공급에 따른 유입원의 증가와 함께 5월 대비 6월(장마철) 흐린날(Cloudy condition) 증가에 따른 상대적인 순복사에너지(5월: 약20만$w/m^2$, 6월: 약17만$w/m^2$)의 감소가 주 원인이였던 것으로 검토되었다. 이를 통해 볼 때 무안 증발산량 자료는 추가적인 경년변화 연구가 필요하겠으나, 국가통계자료로써 유의미한 자료로 판단되며, 향후 증발산량에 대한 지속적인 연구 및 관측망의 확대를 통해 국가 이수관련 정책수립에 유용한 자료로 이용 될 수 있을것으로 판단된다.

• The Journal of the Convergence on Culture Technology
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• v.8 no.2
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• pp.379-384
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• 2022

In a wireless sensor network, a large number of sensor nodes are deployed in an environment where direct access is difficult. It is difficult to supply power, such as replacing the battery or recharging it. It is very important to use the energy with the sensor node. Therefore, an important consideration to increase the lifetime of the network is to minimize the energy consumption of each sensor node. If the energy of the wireless sensor node is exhausted and discharged, it cannot function as a sensor node. Therefore, it is a method proposed in various protocols to minimize the energy consumption of nodes and maintain the network for a long time. We consider the center point and residual energy of the cluster, and the plot point and K-means (WSN suggests optimal clustering). We want to evaluate the performance of the KOCED protocol. We compare protocols to which the K-means algorithm, one of the latest machine learning methods, is applied, and present performance evaluation factors.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.479-479
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• 2023

하천의 건천화는 물이용은 물론 수질과 수생태 측면에서 부정적인 영향을 주는 것으로 알려져 있으나, 건천화의 정의는 물론 건천화 판단기준에 대해서도 학술적인 정리가 부족한 실정이다. 국내의 하천환경을 고려할 때 대부분의 건천화는 대하천이나 하천의 본류보다는 중소하천 규모에서 발생하고 있으며, 이는 만경강유역에서도 동일할 것으로 판단된다. 건천화를 판단하기 위해서는 장기간에 걸친 신뢰할 만한 유량자료가 축적되어 있어야 하나, 중소하천 규모에서 장기측정망을 운영하기는 쉽지 않은 특성으로, 이를 보완하는 방법으로 현장에서의 유량 측정과 함께 모형을 이용하여 하천의 유황을 추정하는 것이 타당할 것으로 판단된다. 건천화된 하천의 유량확보와 관련하여 고려할 수 있는 하천유지유량 제도는 국가하천과 지방 하천을 대상으로 하고 있어 실제 건천화가 발생하는 중소하천에는 적용하기 어려울 것으로 보여, 환경생태유량 제도의 활용을 검토하는 것이 바람직할 것으로 보이지만, 중소하천이나 그 이하 규모의 소하천의 경우 유량 확보를 위한 현실적인 방안이 제한되어 있는 문제가 있다. 본 연구에서는 선행연구에서 제시한 기준유량과 건천화 평가지표를 검토하고 적용하였다. 또한 하천유역의 특성을 반영하기 위해 대조하천, 농업하천, 도시하천, 준도시하천으로 구분하고 이들 하천에 대한 현장조사와 함께 장기유출모형을 구축하여 하천의 유황을 파악하고 만경강유역의 건천화 규모를 추정하였다. 건천화 등급을 산정한 결과, 건천화율이 대부분 5등급(매우나쁨)수준으로 평가었고, 산정된 건천화 비율로 살펴봤을 때, 건천화를 개선하기 위한 유량공급이 필요한 단계로 사료된다. 이러한 연구 결과는 향후 건천화현상에 대한 원인규명과 방지대책을 강구하기 위한 기초자료로 활용가능 할 것으로 판단된다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.322-323
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• 2022

The most necessary thing for the optimal operation of a water purification plant is to accurately predict the pattern and amount of tap water used by consumers. The required amount of tap water should be delivered to the drain using a pump and stored, and the required flow rate should be supplied in a timely manner using the minimum amount of electrical energy. The short-term demand forecasting required from the point of view of energy optimization operation among water purification plant volume predictions has been made in consideration of seasons, major periods, and regional characteristics using time series analysis, regression analysis, and neural network algorithms. In this paper, we analyzed energy management methods through AI-based complex sensor applicability analysis such as LSTM (Long Short-Term Memory) and GRU (Gated Recurrent Units), which are types of cyclic neural networks.

• Journal of the Korean Institute of Gas
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• v.28 no.1
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• pp.53-58
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• 2024

Due to the development of industry and improvement of living standards, the amount of natural gas used in the world is constantly increasing, and related industrial facilities such as power plants, storage facilities, and supply pipelines are constantly increasing. Natural gas is a convenient and clean fuel that does not pollute the environment, but in the event of an accident due to leakage, it can cause human casualties, large-scale property damage, and negative effects on the global warming effect. In addition to the severe penalties under the Severe Disaster Punishment Act, it is necessary to ensure safety. Therefore, by applying the principle of laser-based absorption spectroscopy, we developed a long-range portable methane leakage gas detection system that can detect the concentration of methane leaking from a distance of up to 30 meters and verified its effectiveness.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.12
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• pp.641-646
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• 2016

Soil organic matter (SOM) is an important soil component releasing nutrients to the plants and reducing risks of soil contamination to the human and ecosystem. Much attention has been recently paid to SOM investigation and management because SOM holds the most of carbon in the earth and sequestrate carbon as a sink tank. The first objective of the study was to investigate SOM of 495 soil samples taken at the Korea Soil Quality Monitoring Network. Soil samples were collected from 16 regions and 8 land use types. The second objective of the study was to find a relationship between the Tyurin method and loss-on-ignition (LOI) method for SOM. The means of SOM by Tyurin and LOI methods were 1.90 and 2.92 % (w/w), respectively. Land uses such as forest, religious area and park where organic matters continuously supply to normally showed higher SOMs than residential and school areas having sandy soils. A regression equation of the relationship between Tyurin and LOI methods was y(Tyurin) = 0.6257x(LOI) + 0.0602 (P-value < 0.001). The coefficient of determination was $R^2=0.749$, relatively linearly related. Although LOI may result in higher SOMs than the Tyurin method, LOI may be a preference for the SOM investigation if various kinds of land uses and many soil samples should be measured.

• Journal of the Korea Society of Computer and Information
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• v.17 no.1
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• pp.61-69
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• 2012

Smart Grid is the next-generation intelligent power grid that maximizes energy efficiency with the convergence of IT technologies and the existing power grid. Smart Grid is created solution for standardization and interoperability. Smart Grid industry enables consumers to check power rates in real time for active power consumption. It also enables suppliers to measure their expected power generation load, which stabilizes the operation of the power system. Smart industy was ecolved actively cause Wireless communication is being considered for AMI system and wireless communication using ZigBee sensor has been applied in various industly. In this paper, we proposed efficient addressing scheme for improving the performance of the routing algorithm using ZigBee in Smart Grid environment. A distributed address allocation scheme used an existing algorithm has wasted address space. Therefore proposing x, y coordinate axes from divide address space of 16 bit to solve this problem. Each node was reduced not only bitwise but also multi hop using the coordinate axes while routing than Cskip algorithm. I compared the performance between the standard and the proposed mechanism through the numerical analysis. Simulation verify performance about decrease averaging multi hop count that compare proposing algorithm and another. The numerical analysis results show that proposed algorithm reduce multi hop than ZigBee distributed address assignment and another.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.5
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• pp.673-681
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• 2011

Among the network information services combined with a number of security technologies and required security policies, Infrastructure as a Service, a hardware plat-form service of Cloud Computing, has been provided since 2011. It is more or less similar to the existing central concentration method services, in terms of the specifications and technical aspects for given hardware category, but it is entirely different from them in that it overcomes the spatial limitations of specific network and targets the public network. Information security technology has also been prospering so that it could ensure the stability of offered hardware plat-forms. As currently supported hardware, Internet Data Center has been provided by virtualizing the previously offered servers and discs (backup discs), but the hardware plat-forms offered are somewhat limited. Meanwhile, the areas of security fields for offered services are confined to the center or include the TCP/IP-based SSL (Secure Sockets Layer) for the public network connected with clients, which shows that microscopic access security policies have been used. Therefore, this study was aimed to provide a realistic security mechanism for realizing defense policy, by expanding service areas into security devices and suggesting Diskless and Stateless security policy based high-speed synchronous network infrastructure.

• Journal of Korea Water Resources Association
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• v.55 no.11
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• pp.903-911
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• 2022

Groundwater, one of the resources for supplying water, fluctuates in water level due to various natural factors. Recently, research has been conducted to predict fluctuations in groundwater levels using Artificial Neural Network (ANN). Previously, among operators in ANN, Gradient Descent (GD)-based Optimizers were used as Optimizer that affect learning. GD-based Optimizers have disadvantages of initial correlation dependence and absence of solution comparison and storage structure. This study developed Gradient Descent combined with Harmony Search (GDHS), a new Optimizer that combined GD and Harmony Search (HS) to improve the shortcomings of GD-based Optimizers. To evaluate the performance of GDHS, groundwater level at Icheon Yullhyeon observation station were learned and predicted using Multi Layer Perceptron (MLP). Mean Squared Error (MSE) and Mean Absolute Error (MAE) were used to compare the performance of MLP using GD and GDHS. Comparing the learning results, GDHS had lower maximum, minimum, average and Standard Deviation (SD) of MSE than GD. Comparing the prediction results, GDHS was evaluated to have a lower error in all of the evaluation index than GD.

• Journal of Navigation and Port Research
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• v.48 no.3
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• pp.181-191
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• 2024

Ports play a crucial role in the complex global supply chain. While many researchers have used social network analysis (SNA) to study active networks, there is a lack of SNA cohesion analysis specifically related to logistics and trade. Therefore, this study aims to identify time-series structural changes in all domestic import and export logistics networks, including regions, ports, and airports, by utilizing techniques such as k-core and community analysis. To carry out this analysis, we rely on data from the Korea Customs Service's Import and Export Logistics Statistical Yearbook spanning from 2004 to 2022. The findings from the k-core and community analysis indicate that the cohesion of the domestic import and export logistics network has continuously strengthened over time. Moreover, it reveals that regions, ports, and airports are becoming more cohesive and homogeneous, with Busan Port emerging as the central hub of a large community. These insights are expected to enhance our understanding of global logistics dynamics and contribute to the development of policies and sustainable import and export logistics processes.