• Journal of Korea Water Resources Association
• /
• v.44 no.7
• /
• pp.553-563
• /
• 2011

According to the improvement of computer's performance, the development of Geographic Information System (GIS), and the activation of offering information, a distributed model for analyzing runoff has been studied a lot in recently years. The distribution model is a theoretical and physical model computing runoff as making target basin subdivided parted. In the distributed model developed by this study, the volume of runoff at the surface flow is calculated on the basis of the parameter determined by landcover data and a two-dimensional diffusion wave equation. Most of existing runoff models compute velocity and discharge of flow by applying Manning-Strickler's mean velocity equation and Manning's roughness coefficient. Manning's roughness coefficient is not matched with dimension and ambiguous at computation; Nevertheless, it is widely used in because of its convenience for use. In order to improve those problems, this study developed the runoff model by applying not only Manning-Strickler's equation but also Chezy's mean velocity equation. Furthermore, this study introduced a power law of exponential friction factor expressed by the function of roughness height. The distributed model developed in this study is applied to 6 events of fan-shape basin, oblong shape test basin and Anseongcheon basin as real field conditions. As a result the model is found to be excellent in comparison with the exiting runoff models using for practical engineering application.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.12
• /
• pp.1340-1346
• /
• 2005

A water quality modeling study was performed for Chunggye stream during combined sewer overflow(CSO) period, utilizing the diagnostic system for water management in small watershed, CREEK-1(Cyber River for Environment and Economy in Korea). This system integrated geogaphic information system, data base, landscape ecological model(FRAGSTATS), watershed model(SWMM), water quality model (WASP5), and computer graphic. In this study, the watershed model and water quality model were extensively utilized so as to simulate water qualities and flow in Chunggye stream during wet periods. The Chunggye stream watershed was divided into 18 sub-basins in the watershed model and the stream reach into 11 segments in the water quality model. The watershed model was validated against field measurements of BOD, TN, TP, and flow at the downstream location, where the model results showed a reasonable agreement with the field measurements at all parameters. From this study, it was shown that the stream water quality would change along with elapsed time from rainfall start as well as rainfall intensity. The model results indicated that the water quality would significantly upgrade due to the first flush and high sewage ratio of CSO at the beginning of rainfall event, but become degraded along with the runoff increase due to dilution effect.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.11a
• /
• pp.174-174
• /
• 2008

초음파를 이용하여 액체 연료를 분사하면 균일한 입경과 미립화가 우수하며 에너지 절약과 공해방지등을 할 수 있다. 또한 유속과 유량에 관계없이 이용할 수 있어 반도체 분야의 웨이퍼와 평판 표시기상에 사진 석판용 화학물질의 균일도포 컴퓨터 하드 디스크의 광택제 도포등에 사용할 수 있다. 이처럼 초저의 유출 용량을 요구하는 모든 공정 및 액체연료의 분사가 요구되는 모든 산업에 적용할 수 있는 장점을 가지고 있다. 하지만 현제까지 주로 사용되고 있는 초음파노즐의 액츄에이터는 단판액츄에이터형로 높은 교류전압을 인가해주어야 하는 단점을 가지고 있다. 이 단점을 해결하기 위해 적층액츄에이터형을 사용하여 초음파 노즐 구동하면 낮은 교류 입력전압에서도 단판액츄에이터형 초음파 노즐과 같은 특성을 가질 수 있다. 또한 초음파 노즐의 구동시 기계적인 진동을 이용하므로 많은 열을 발생시켜 노즐의 온도가 상승하여 세라믹 액츄에이터에도 그 영향을 미치게 되어 열적 열화 현상이 일어날 수 있기에 높은 큐리온도를 가지는 액츄에이터가 필요하다. 본 실험에서는 $Pb(Mn_{1/3}Nb_{2/3})_{0.02}(Ni_{1/3}Nb_{2/3})_{0.12}(Zr_{0.50}Ti_{0.50})_{0.86}O_3$ 조성을 사용하여 $900^{\circ}C$의 저온에서 액상 소결하여 적층혈액츄에이터를 제작하였으며 압전 및 유전 특성을 조사하였다. 제작된 초음파노즐을 구동하기 위해서는 약 36kHz의 30V이상의 교류입력전압 할 수 있는 구동회로가 필요로 한다. 압전액츄에이터의 구동을 위해서는 정확한 정현파 입력이 필요 없다. 압전액츄에이터의 특성상 유사 정현파 입력 만으로도 임피던스 매칭이 이루어지기 때문에 설계가 쉽고 간편한 Push-Pull 방식을 이용한 PWM인버터를 사용하였고 인버터의 출력 주파수를 34~38kHz까지 가변 할 수 있게 설계하였다. 제작된 적층액츄에이터형 초음파 노즐을 PWM인버터로 실제 액체 연료인 경유를 분사하였을 때의 액츄에이터의 온도 변화에 따른 공진주파수와 온도 의존성, 전기적 특성을 조사하고 미립화 분사되는 경유의 미립자 크기 및 최대 분사량을 조사 하였다.

• The Journal of the Convergence on Culture Technology
• /
• v.9 no.3
• /
• pp.789-795
• /
• 2023

Digital-Twin are recognized as an important core technology for the realization of Smart Factories by simulating and optimizing the monitoring and predictive maintenance of manufacturing equipment and the operation of production lines in a digital space. To implement this system, we adopt the IEC62541-based OPC-UA (Open Platform Communications Unified-Architecture) Protocol, which has strengths in interoperability and connectivity between heterogeneous platforms. Therefore, In this paper, We designed and implemented an IIoT(Industry Internet of Things) system that connects heterogeneous platforms, and developed an OPC-UA simulator based on IEC 62541. We will present whether the data will be applied to the Digital-Twin Platform and whether it will work, and proceed with performance tests and evaluations. We evaluate the operation performance and OPC-UA performance of the Digital-Twin platform lightened by the proposed device, and present the optimal IEC62514-based simulator system. We proceeded with the performance evaluation of sending and receiving data with OPC-UA wrapping with the proposed simulator, and found that a lightweight Digital-Twin platform can be operated. This research can apply the OPC-UA protocol for implementing smart factory and meta-factory in the manufacturing shop floor with limited resources, avoiding the waste of time and space on the shop floor through the OPC-UA simulator. We expect that this will contribute to a significant improvement in efficiency by minimizing.