• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.377-384
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• 2002

In this palter, a finite element technique is applied to both reinforced concrete and prestressed concrete containment vessels to predict the ultimate pressure capacity of the vessels subjected to internal pressure due to accident. The so-called volume-control technique is utilized to control the change in volume enclosed by the cylindrical containment vessels and layered shell elements equipped with a pressure node is utilizing to model the PSC vessels. The finite element analysis is carried out to obtain both global and local failure behavior of prestressed concrete nuclear containment vessels. nalytical results are verified by comparison with experimental data.

• Coupled systems mechanics
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• v.4 no.4
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• pp.317-336
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• 2015

The present paper deals with the analysis of water tank with elastic separator wall. Both fluid and structure are discretized and modeled by eight node-elements. In the governing equations, pressure for the fluid domain and displacement for the separator wall are considered as nodal variables. A method namely, direct coupled for the analysis of water tank has been carried out in this study. In direct coupled approach, the solution of the fluid-structure system is accomplished by considering these as a single system. The hydrodynamic pressure on tank wall is presented for different lengths of tank. The results show that the magnitude of hydrodynamic pressure is quite large when the distances between the separator wall and tank wall are relatively closer and this is due to higher rotating tendency of fluid and the higher sloshed displacement at free surface.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.8
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• pp.4212-4226
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• 2019

In this paper, a design and implementation for direct deal distribution platform is proposed to bypass the complex traditional distribution structure of agricultural market, as one of the fields where distribution patterns have changed. In the case of domestic agricultural distribution, demand and supply are unstable since the sales market is excessively concentrated in the designated wholesale market. Besides sales must go through multiple stages of distribution leading to problems in freshness and stability of agricultural products and downward pressure on profit margins for producers. To solve the above mentioned issues, we propose a cloud service convergence direct deal distribution platform based on asynchronous-driven Node.js. The proposed platform can facilitate a variety of direct trading functions and also access to visualization information related to agricultural products, which may increase user confidence at an intermediary-free direct transactions platform. First, we describe the requirements of intermediary-free direct transactions of agricultural products and transaction entities. Next the database structure and transaction functions are designed and then implemented according to those requirements. Finally, an API based cloud convergence service structure is designed to provide the analyzed information to ensure a trustworthy system.

• Archives of Plastic Surgery
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• v.49 no.4
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• pp.549-553
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• 2022

Chylothorax is a rare disease and massive lymph fluid loss can cause life-threatening condition such as severe malnutrition, weight loss, and impaired immune system. If untreated, mortality rate of chylothorax can be up to 50%. This is a case report of a 3-year-old child with iatrogenic chylothorax. Despite conservative treatment and procedures, like perm catheter insertion, the patient failed to improve the respiratory symptoms over 3 months of period. As an alternative to surgical option, such as pleurodesis and thoracic duct ligation which has high complication rate, the patient underwent lymphovenous anastomosis (LVA) and lymph node to vein anastomosis (LNVA). Follow-up at fourth month showed clear lungs without breathing difficulty despite perm catheter removal. This is the first report to show the effectiveness of LVA and LNVA against iatrogenic chylothorax.

• Journal of the Institute of Convergence Signal Processing
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• v.23 no.2
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• pp.50-61
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• 2022

This work demonstrates the design and evaluation of Aqua-Aware, a lightweight miniaturized light emitting diode (LED) based underwater compact sensor node which is used to obtain different characteristics of the underwater environment. Two optical sensor nodes have been designed, developed, and evaluated for a short and medium link range called as Aqua-Aware short range (AASR) and Aqua-Aware medium range (AAMR), respectively. The hardware and software implementation of proposed sensor node, algorithms, and trade-offs have been discussed in this paper. The underwater environment is emulated by introducing different turbulence effects such as air bubbles, waves and turbidity in a 4-m water tank. In clear water, the Aqua-Aware achieved a data rate of 0.2 Mbps at communication link up to 2-m. The Aqua-Aware was able to achieve 0.2 Mbps in a turbid water of 64 NTU in the presence of moderate water waves and air bubbles within the communication link range of 1.7-m. We have evaluated the luminous intensity, packet success rate and bit error rate performance of the proposed system obtained by varying the various medium characteristics.

• Journal of Korea Water Resources Association
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• v.40 no.4
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• pp.325-334
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• 2007

In this study, a long-term unsteady simulation model has been developed using rigid water column theory which is more accurate than Extended-period model and more efficient comparing with water-hammer simulation model. The developed model is applied to 24-hours unsteady simulation considering daily water-demand and water-hammer analysis caused by closing a valve. For the case of 24-hours daily simulation, the pressure of each node decreases as the water demand increase, and when the water demand decrease, the pressure increases. During the simulation, the amplitudes of flow and pressure variation are different in each node and the pattern of flow variation as well as water demand is quite different than that of KYPIPE2. Such discrepancy necessitates the development of unsteady flow analysis model in water distribution network system. When the model is applied to water-hammer analysis, the pressure and flow variation occurred simultaneously through the entire network system by neglecting the compressibility of water. Although water-hammer model shows the lag of travel time due to fluid elasticity, in the aspect of pressure and flow fluctuation, the trend of overall variation and quantity of the result are similar to that of water-hammer model. This model is expected for the analysis of gradual long-term unsteady flow variations providing computational accuracy and efficiency as well as identifying pollutant dispersion, pressure control, leakage reduction corresponding to flow-demand pattern, and management of long-term pipeline net work systems related with flowrate and pressure variation in pipeline network systems

• Structural Engineering and Mechanics
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• v.71 no.6
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• pp.699-712
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• 2019

The reinforced concrete lining of hydraulic pressure tunnels tends to crack under high inner water pressure (IWP), which results in the inner water exosmosis along cracks and involves typical hydro-mechanical interaction. This study aims at the development, validation and application of an indirect-coupled method to simulate the lining cracking process. Based on the concrete damage plasticity (CDP) model, the utility routine GETVRM and the user subroutine USDFLD in the finite element code ABAQUS is employed to calculate and adjust the secondary hydraulic conductivity according to the material damage and the plastic volume strain. The friction-contact method (FCM) is introduced to track the lining-rock interface behavior. Compared with the traditional node-shared method (NSM) model, the FCM model is more feasible to simulate the lining cracking process. The number of cracks and the reinforcement stress can be significantly reduced, which matches well with the observed results in engineering practices. Moreover, the damage evolution of reinforced concrete lining can be effectively slowed down. This numerical method provides an insight into the cracking process of reinforced concrete lining in hydraulic pressure tunnels.

• Journal of the Korean Society of Visualization
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• v.20 no.2
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• pp.78-85
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• 2022

In these days, the rapid development in prediction technology using artificial intelligent is being applied in a variety of engineering fields. Especially, dimensionality reduction technologies such as autoencoder and convolutional neural network have enabled the classification and regression of high-dimensional data. In particular, pixel level prediction technology enables semantic segmentation (fine-grained classification), or physical value prediction for each pixel such as depth or surface normal estimation. In this study, the pressure distribution of the ship's surface was estimated at the pixel level based on the artificial neural network. First, a potential flow analysis was performed on the hull form data generated by transforming the baseline hull form data to construct 429 datasets for learning. Thereafter, a neural network with a U-shape structure was configured to learn the pressure value at the node position of the pretreated hull form. As a result, for the hull form included in training set, it was confirmed that the neural network can make a good prediction for pressure distribution. But in case of container ship, which is not included and have different characteristics, the network couldn't give a reasonable result.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.10a
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• pp.405-412
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• 1998

According to the relative stiffness between the half-space and plate or loading condition, some parts of the plate can be separated from the half-space. The finite element procedure to determine the contact area by considering the distribution of contact pressure between plate and the elastic half-space is developed. The vertical surface displacements of the elastic half-space can be obtained through the integrations of the Boussinesq's solution for a point load. The rectangular plate on the elastic half-space is modeled by the 8-node rectangular and 6-node triangular elements and the Mindlin plate theory is used in oder to consider the transverse shear effect. In this study, the contact area may be determined approximately by the analysis with rectangular elements. From this results, the mesh pattern is modified by using triangular and rectangular elements. The contact area can be determined by the new mesh pattern with a relatively sufficient accuracy.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.3
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• pp.281-291
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• 1999

A computer code based on a node equation method has been developed for the analysis of pipe network. Both data structure and object-oriented programming technique are used for pipe and node modelling, in which simplification process is applied to complicated and large pipe network. The semi-direct solver, ILU-CGS, improves greatly both the accuracy and the rate of convergence. The computational result of high-pressure pipe network of city gas in Taegu shows the good agreement with the real data.