• Water for future
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• v.26 no.3
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• pp.125-135
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• 1993

This study was conducted for two purposes. The first was the selection of the proper model for the urban runoff, and NPS(non-point source) loads and the second was the adjustment of the selected model through the calibration and the verification of the observed data on an urban drainage basin. The selected model for this study was the Storm Water Management Model(SWMM) developed and maintained by the US Environmental Protection Agency(EPA). In particular, the Runoff Block for the surface discharge and the Transport Block for the flow routing was used. The study basin is Youngdu basin, which is a typical developed urban drainage basin. The four rainfall events for the runoff and the two for the four NPS pollutants(SS, BOD, COD and TN) were used for the calibration and the estimation of the model parameters. This study performed the calibration with regard to the peak discharge, the time to peak discharge, the volume and the relative error for three items. It was shown that SWMM can successfully be used for the prediction of the runoff and the NPS pollutants discharge. The result of this study can be used as the basis for the analysis of the correlation between the runoff and the NPS pollutants discharges, and the analysis of the mass balance with the monthly and annual NPS loads in an urban drainage basin.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.521-521
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• 2016

상수도 관망은 수원에서 수요절점까지 물을 안정적으로 공급하는 것을 목표로 한다. 상수도 관망의 최적설계는 수리학적 제한조건 (절점의 수압, 관로의 유속)을 만족하는 범위에서 비용을 최소화하는 설계안을 얻는 것으로 Savic and Walters (1997)는 유전 알고리즘 (Genetic Algorithms, Holland 1975)을 적용한 상수도 관망 설계 프로그램인 GANET를 제안하였고, Maier et al. (1996)은 개미군집알고리즘 (Ant Colony Optimization Algorithm, Dorigo et al. 1996)을 상수도 관망 최적설계에 적용한 후 그 결과가 유전 알고리즘에 비해 우수함을 증명하는 등 상수도 관망 최적설계에 관한 연구가 활발히 진행되어 오고 있다. 유전알고리즘은 선택, 교차, 돌연변이의 반복계산 과정을 통하여 최적해를 찾는 최적화 기법이다. 이 과정에서 결정변수는 유전자 (Gene)의 집합으로 표현되며, 염색체 (Chromosome) 내에서 근접한 유전 인자들은 일종의 Building Block을 형성하게 된다. Building Block은 좋은 해를 갖는 유전 인자를 높은 확률로 보관하여 지역해에 빠질 가능성을 줄이는 반면, 유전형 (Genotype)이 표현형 (Phenotype)을 충분히 모방하여 표현하지 못한 경우 오히려 최적해의 탐색을 방해할 수 있다는 한계점을 갖는다. 유전 알고리즘을 상수도 관망 최적설계에 적용하였을 때에도 이 한계점은 여실히 드러난다. 관로의 관경을 결정변수로 설정한 후 유전형으로 표현하였을 때, 관망도 상에서 근접하지 않은 두 관로가 염색체 내에서 연속으로 나열된다면 두 관로 간의 연관성이 실제보다 크게 고려되기 때문이다. 한편, 하모니써치 (Harmony Search, Geem et al. 2001) 알고리즘은 즉흥 연주 (Improvisation)를 통해 최상의 화음을 만들어내는 현상으로부터 착안하여 만들어진 최적화기법으로 연산 기법은 무작위선택, 기억회상, 피치조정 등으로 구성되어 있으며, 결정변수에 해당하는 연주자가 독립적으로 행동하며 해를 탐색한다는 점에서 유전알고리즘과 큰 차이를 갖는다. 본 연구에서는 유전알고리즘의 Building Block에 의해 발생하는 오류를 개선하고자, 상수도 관망 최적설계 연구에 많이 사용되는 Hanoi 관망 (Fujiwara and Khang 1990) 관로의 정렬 순서를 여러 가지 기준으로 설정하여 관망데이터를 구축한 후 하모니써치와 유전 알고리즘을 적용하여 최적화를 수행하였고 그 결과를 비교하였다. 그 결과 유전 알고리즘과 달리 하모니써치 알고리즘의 경우, 관로의 나열 순서와 상관없이 우수한 최적해 탐색 결과를 보이는 것을 확인할 수 있었다.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.6
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• pp.15-20
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• 2008

Hydraulic analysis of water distribution system can be divided into demand-driven analysis and pressure-driven analysis. Demanddriven analysis can give unrealistic results to simulate hydraulic conditions under abnormal operating conditions such as sudden demand increase and pipe failure. In Korea, demand-driven analysis has been used to establish emergency water supply plan in many water projects, but it is necessary to use pressure-driven analysis for establishment of emergency water supply plan. In this study, WaterGEMS model that was developed for pressure-driven analysis is used to evaluation of emergency water supply plan of J city. As the results, it was able to draw up more efficient plan for water supply in small block, and established emergency water supply plan of J city was determined to be appropriate.

• Computational Structural Engineering
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• v.9 no.1
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• pp.55-64
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• 1996

Sloshing frequencies of the fluid in rectangular tanks with a bottom-mounted rectangular block are determined by linear water wave theory. Velocity potential is decomposed into those for the wall-induced waves, and the reflected, transmitted, and scattered waves by the block. The reflection and transmission coefficients are determined using the continuity conditions of mass flux and energy flux on the common vertical boundaries of the fluid regions, and the boundary conditions on the both sides of the block. The analysis results indicate that the sloshing frequencies reduce, as the block becomes tall and vade and as the block moves toward the center. The variations of the sloshing frequencies due to the block are found to be more sensitive in broad thanks than is tall tanks.

• Bulletin of the Korean Chemical Society
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• v.19 no.9
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• pp.962-967
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• 1998

Block copolymers consisting of poly(rbenzyl L-glutamate) (PBLG) as the hydrophobic part and poly(ethylene oxide) (PEO) as the hydrophilic part were synthesized and characterized. Polymeric micelles of the block copolymers (abbreviated GEG) were prepared by a dialysis method. The GEG block copolymers were associated in water to form polymeric micelles, and the critical micelle concentration (CMC) values of the block copolymers decreased with increasing PBLG chain length in the block copolymers. Transmission electron microscopy (TEM) observations revealed polymeric micelles of spherical shapes. From dynamic light scattering (DLS) study, sizes of polymeric micelles of GEG-1, GEG-2, and GEG-3 copolymer were 106.5±59.2 nm, 79.4±46.0 nm, and 37.9±13.3 nm, respectively. The drug loading contents of GEG-1, GEG-2 and GEG-3 polymeric micelles were 12.6, 11.9, and 11.0 wt %, respectively. These results indicated that the drugloading contents were dependent on PBLG chain length in the copolymer; the longer the PBLG chain length, the more the drug-loading contents. Release of norfloxacin (NFX) from the nanoparticles was slower in higher loading contents of NFX than in lower loading contents due to the hydrophobic interaction between PBLG core and NFX.

• Bulletin of the Korean Chemical Society
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• v.25 no.7
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• pp.1025-1030
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• 2004

A hybrid linear polymer-dendrimer block copolymer, poly(ethylene glycol)-block-poly(L-lysine) dendrimer, was synthesized and introduced to form polyionic complexes with DNA. The copolymer formed core-shell type nanoparticles with plasmid DNA. From dynamic light scattering experiments, the mean diameter of the polyplexes was observed to be 154.4 nm. The complex showed much increased water solubility compared to poly(L-lysine). The plasmid DNA in polyplexes was efficiently protected from the enzymatic digestion of DNase I. The cytotoxicity and transfection efficiency for 293 cells was measured in comparison with poly(Llysine).

• Progress in Medical Physics
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• v.1 no.1
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• pp.61-68
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• 1990

We have designed the calculation model(AMC method) of electron output for the cut-out fieldsand studied the influence of shielding block size. The output of electron was measured in the water phantom at dmax, for 20 $\times$ 20cm$^2$ cone size electron beams from CL/1800 linear accelerator(Varian, USA), Which generates the energy of 6, 9, 12, 15 and 18MeV electron beams. The shielding blocks were rectangular or squre shaped, low melting point alloy. We can predict the output from the arbitrarily rectangular shaped block within 1% error. by using the AMC method, which considers the contribution of the collimator(block) scatter and the phantom scatter.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.327-332
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• 2003

The incinerated municipal waste can be classified into two general types of ash; fly ash and bottom ash. The fly ash is appointed as specified waste, because it contains harmful heavy metals, ie Pb , Cd, etc. more than permitted standard index. The purpose of this study is to manufacture the non-sintering artificial aggregates using municipal waste incineration fly-ash and to evaluate their applications as coarse aggregates in concrete interlocking block. The test results of water absorpsion, strengths of the concrete block using artificial aggregates showed that the artificial aggregates could be used in part of 10-20% as coarse aggregate in concrete block.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.327-330
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• 1996

Poly(L-leucine)(PLL)/poly(ethylene oxide)(PEO)/poly (L-leucine)(PLL) block copolymers were synthsized by polymerization of L-leucine N-carboxyanhydride with diamine-terminated PEO for possibility of wound dressing which may have several advantages such as 1) increase of solubility, 2) control of biodegradation, 3) absorption of body fluid. 4) non-immunogenic effect than PLL homopolymer wound dressing aleady commercialized. Water content increased with an increase of PEO content in the block copolymer due to the hydrophilicity of PEO. Release of silver sulfadiazine(AgSD) from AgSD loaded wound dressing increased with an increase of PEO content in the block copolymer. It was found that the number of Pseudomonas aeruginosa decrease with an increase of PEO content due to the fast release of antibacterial agents with an increase of PEO content in the block copolymer.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.4237-4244
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• 2015

This study examined the efflorescence characteristics of a concrete sidewalk block manufactured using recycled stone powder sludge and photocatalytic generated by surface polishing during the sidewalk block manufacturing process. The study evaluated the characteristics of the sidewalk block in terms of its quality, based on the amount of stone powder sludge used, efflorescence, and further based on the mixing ratio and number of applications of the photocatalytic. The experimental results indicated that heavy metals such as lead, hexavalent chrome, cadmium, and mercury were not present in the concrete sidewalk block, thereby confirming the effectiveness of the recycled stone powder sludge. The optimum mixing ratio of used in the concrete sidewalk block (for satisfying KS standard values such as water absorption ratio and flexural strength) was found to be 20%. The concrete sidewalk block incorporating the stone powder sludge and photocatalytic exhibited a water absorption ratio of 5.4% and flexural strength of 5.2 MPa, thereby satisfying the quality standards. Additionally, when the photocatalytic was used, efflorescence did not occur even at the low temperature of $-5^{\circ}C$, and the by the sidewalk block was found to be 70% under normal conditions and 68% when subjected to an accelerated weathering test.