• Bulletin of the Korean Mathematical Society
• /
• v.44 no.4
• /
• pp.691-699
• /
• 2007

The notion of perfect filters and concrete filters in WFI-algebras is introduced, and several properties are investigated. Relations between a filter, a perfect filter and a concrete filter are given, and characterizations of a perfect filter and a concrete filter are provided. An extension property for a concrete filter and a perfect filter is established.

• Korean Journal of Materials Research
• /
• v.32 no.4
• /
• pp.223-229
• /
• 2022

A porous photocatalyst concrete filter was successfully produced to remove NOx, by mixing TiO₂ photocatalyst with lightweight aerated concrete. Ultra Fine Bubbles were used to form continuous pores inside the porous photocatalytic concrete filter, which was mixed via a bubble generation experiment. The optimal mixing condition was determined to be with 4 % of the bubble generation agent B. NO removal specimens were prepared for various photocatalytic loading conditions, and the specimen containing 3 % P-25 removed NO at a concentration of 1.03 µmol in 1 h. The NO removal rate of the porous photocatalytic concrete filter prepared in this study was 10.99 %. This photocatalytic filter performance was more than 9 times the amount of NO removed by a general photocatalytic filter. The porous photocatalyst concrete filter for removing NOx developed in this study can be applied to various construction sites and the air quality can be solved by reducing NOx contributing to the formation of fine particles.

• Journal of applied mathematics & informatics
• /
• v.26 no.5_6
• /
• pp.925-932
• /
• 2008

The notion of weak filters in WFI-algebras is introduced. Relations between weak filters and concrete filters are established. A condition for a filter to be closed is given. Also, a condition for a filter to be a weak filter is provided. Characterizations of weak and concrete filters are discussed. A condition for a subalgebra to be a concrete filter is given.

• Honam Mathematical Journal
• /
• v.30 no.1
• /
• pp.119-126
• /
• 2008

The notion of uncanny filter is introduced, and related properties are investigated. Relations between uncanny filter, closed filter, and concrete filter are given. Characterizations of uncanny filter are provided. Extension property for uncanny filter is established.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1998.04a
• /
• pp.237-242
• /
• 1998

Covering mortar as a filter for permeable polymer concrete is necessary for good permeability from filtration continuously. Therefore, this paper is intended as an evaluation of the mechanical properties and permeability of permeable polymer concrete covered with polymer mortar as a filter. An optimum permeable polymer concrete is selected in various mix proportions, and three different polymer mortars were cast immediately following on the casting of the base permeable polymer concrete. And they are tested for compressive and flexural strengths, adhesion in tension, hardening shrinkage and permeability . From the test results, binder and filler contents in mix proportions had a great influence on the permeability of polymer concretes. The mechanical properties of permeable polymer concretes covered with polymer mortars using crushed stone are superior to other filters, and hardening shrinkage is the smallest in filters. It is apparent that adhesion between the base permeable polymer concrete and polymer mortar is affected by the degree of hardening shrinkage. From this study, proper mix proportions can be recommended in the consideration of properties of the permeable polymer concrete.

• Journal of Environmental Impact Assessment
• /
• v.17 no.5
• /
• pp.271-278
• /
• 2008

The purpose of this research provides the basic solution about waterfront and promotes the inherent capability, that recoveries both the river and gives the river for water quality to improve plan. In this study, we compare and analysis the slope contact between filter media of the porous concrete and planting concrete. As a result, when appling the porous concrete, it can show the removal efficiency is SS 53%, BOD 39%, COD 20%, T-N 36% T-P 42% and appling planting concrete is SS 58%, BOD42%, COD 26%, T-N 45%, T-P 53%. Therefore, planting concrete is higher removal efficiency (SS 5%, BOD 3%, COD 6%, T-N 9%, T-P 10%) than porous concrete. The experimental results show that using purification filter media on planting concrete is better than on porous concrete, because it have the higher purification filter efficiency. The quality of water improves vegetarian concrete, that can expect the increase of the self-purification capacity and improve the spectacle for providing the waterside and planting of planting concrete. In addition, it can complete and apply the research if having enough time for experimentation and accurate study for mechanism by plant, we can use both planting concrete filter media and the existing dike. As a result, we can gain the better quality of the water of the city's rivers and good economic value, that is spread by all cities applicable technologies. So it can be expected using well for future.

• Smart Structures and Systems
• /
• v.11 no.1
• /
• pp.103-122
• /
• 2013

It is essential to update the model with reflecting observation or inspection data for reliability estimation of existing structures. Authors proposed updated reliability analysis by using Particle Filter. We discuss how to apply the proposed method through numerical examples on reinforced concrete structures after verification of the method with hypothetical linear Gaussian problem. Reinforced concrete structures in a marine environment deteriorate with time due to chloride-induced corrosion of reinforcing bars. In the case of existing structures, it is essential to monitor the current condition such as chloride-induced corrosion and to reflect it to rational maintenance with consideration of the uncertainty. In this context, updated reliability estimation of a structure provides useful information for the rational decision. Accuracy estimation is also one of the important issues when Monte Carlo approach such as Particle Filter is adopted. Especially Particle Filter approach has a problem known as degeneracy. Effective sample size is introduced to predict the covariance of variance of limit state exceeding probabilities calculated by Particle Filter. Its validity is shown by the numerical experiments.

• Journal of the Society of Disaster Information
• /
• v.14 no.4
• /
• pp.458-465
• /
• 2018

Purpose: Concrete track that affects on railway safety can detect cracks using image processing technique. However, since a condition of concrete track and surface noisy are obstructed to detect cracks, there is a need for a way to remove them effectively. Method: In this study, we proposed an image processing to detect cracks effectively for Korean railway and verified its performance through experiment. We developed image acquisition system for capture a railway concrete track and acquired railway concrete track images, randomly selected 2000 images and detected cracks in the image process using proposed Gabor Filter Bank methods. Results: As a result, 94% of detection rate are matched to the actual cracks in same quality and format railway concrete track image. Conclution: The crack detection method using Garbor Filter Bank was confirmed to be effective for crack image including noise in the Korean railway concrete track. This system is expected to become an automated maintenance system in the existing human-centered railway industry.

• Smart Structures and Systems
• /
• v.14 no.4
• /
• pp.719-741
• /
• 2014

Monitoring surface cracks is important to ensure the health of concrete structures. However, traditional visual inspection to monitor the concrete cracks has disadvantages such as subjective inspection nature, associated time and cost, and possible danger to inspectors. To alter the visual inspection, a complete procedure for automated crack assessment based on adaptive digital image processing has been proposed in this study. Crack objects are extracted from the images using the subtraction with median filter and the local binarization using the Niblack's method. To adaptively. determine the optimal window sizes for the median filter and the Niblack's method without distortion of crack object an optimal filter size index (OFSI) is proposed. From the extracted crack objects using the optimal size of window, the crack objects are decomposed to the crack skeletons and edges, and the crack width is calculated using 4-connected normal line according to the orientation of the local skeleton line. For an image, a crack width nephogram is obtained to have an intuitive view of the crack distribution. The proposed procedure is verified from a test on a concrete reaction wall with various types of cracks. From the crack images with different crack widths and patterns, the widths of cracks in the order of submillimeters are calculated with high accuracy.

• Journal of Environmental Science International
• /
• v.15 no.11
• /
• pp.1045-1052
• /
• 2006

Stormwater pollution is a major problem in urban areas. Pollutants like heavy metals and harmful chemicals in the runoff can endanger soil and ground water, when they are not sufficiently removed doting infiltration. Strength and infiltration capacity of porous concrete are the major problems that must be considered if permeable pavement system are demanded to be used in a drive way application. In this study, a series of compacted porous concrete mixtures and the system of pavement ate tested for the physical characteristics like compressive strength, flexural strength, unit weight, porosity, water permeability, and the purification capacity of contaminated water. The test results obtained indicate that the strength and infiltration capacity of porous concrete are strongly related to its matrix proportion and compaction energy and providing adequate filter layers underneath pavement surface course is one of the most important design considerations of permeable pavement system for pollution retention purpose.