Ji-Hong Jeon

Dr. Ji-Hong Jeon


Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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29 January 2016 in Materials
Verified
Journal Article
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KHKim Hwang-Hee
Kim Hwang-Hee
CKChun-Soo Kim
Chun-Soo Kim
JJJi-Hong Jeon
Ji-Hong Jeon
CPChan-Gi Park
Chan-Gi Park
To evaluate the effects of industrial by-products materials on the performance of porous concrete for plant growth, this study investigated the physical, strength, and freeze/thaw resistances of porous concrete for plant growth, prepared by replacing cement with blast furnace slag powder at 60% by weight, and replacing natural stone aggregates with coarse blast furnace slag aggregates at rates of 0%, 20%, 40%, 60% and 100% by weight. In addition, the effects of adding natural jute fiber and styrene butadiene (SB) latex to these concrete mixtures were evaluated. The void ratio, compressive strength, and freeze/thaw resistance of the samples were measured. With increasing replacement rate of blast furnace aggregates, addition of latex, and mixing of natural jute fiber the void ratio of the concrete was increased. Compressive strength decreased as the replacement rate of blast-furnace slag aggregates increased. The compressive strength decreased after 100 freeze/thaw cycles, regardless of the replacement rate of blast furnace slag aggregates or of the addition of natural jute fiber and latex. The addition of natural jute fiber and latex decreased the compressive strength after 100 freeze/thaw cycles. The test results indicate that the control mixture satisfied the target compressive strength of 10 MPa and the target void ratio of 25% at replacement rates of 0% and 20% for blast furnace aggregates, and that the mixtures containing latex satisfied the criteria up to an aggregate replacement rate of 60%. However, the mixtures containing natural jute fiber did not satisfy these criteria. The relationship between void ratio and residual compressive strength after 100 freeze/thaw cycles indicates that the control mixture and the mixtures containing jute fiber at aggregate replacement rates of 20% and 40% satisfied the target void ratio of 25% and the target residual compressive strength of over 80% after 100 freeze/thaw cycles. The mixtures containing latex and aggregate replacement rates up to 60% satisfied the target void ratio and compressive strength.

12 November 2014 in Water
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Journal Article
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JJJi-Hong Jeon
Ji-Hong Jeon
CPChan-Gi Park
Chan-Gi Park
BEBernard Engel
Bernard Engel
Global optimization methods linked with simulation models are widely used for automated calibration and serve as useful tools for searching for cost-effective alternatives for environmental management. A genetic algorithm (GA) and shuffled complex evolution (SCE-UA) algorithm were linked with the Long-Term Hydrologic Impact Assessment (L-THIA) model, which employs the curve number (SCS-CN) method. The performance of the two optimization methods was compared by automatically calibrating L-THIA for monthly runoff from 10 watersheds in Indiana. The selected watershed areas ranged from 32.7 to 5844.1 km2. The SCS-CN values and total five-day rainfall for adjustment were optimized, and the objective function used was the Nash-Sutcliffe value (NS value). The GA method rapidly reached the optimal space until the 10th generating population (generation), and after the 10th generation solutions increased dispersion around the optimal space, called a cross hair pattern, because of mutation rate increase. The number of looping executions influenced the performance of model calibration for the SCE-UA and GA method. The GA method performed better for the case of fewer loop executions than the SCE-UA method. For most watersheds, calibration performance using GA was better than for SCE-UA until the 50th generation when the number of model loop executions was around 5150 (one generation has 100 individuals). However, after the 50th generation of the GA method, the SCE-UA method performed better for calibrating monthly runoff compared to the GA method. Optimized SCS-CN values for primary land use types were nearly the same for the two methods, but those for minor land use types and total five-day rainfall for AMC adjustment were somewhat different because those parameters did not significantly influence calculation of the objective function. The GA method is recommended for cases when model simulation takes a long time and the model user does not have sufficient time for an optimization program to search for the best values of calibration parameters. For other cases, the SCE-UA program is recommended for automatic model calibration.

14 May 2014 in Water
Verified
Journal Article
Open access
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JJJi-Hong Jeon
Ji-Hong Jeon
Kyoung Jae LimKyoung Jae Lim
Kyoung Jae Lim
BEBernard Engel
Bernard Engel
Estimating surface runoff for ungauged watershed is an important issue. The Soil Conservation Service Curve Number (SCS-CN) method developed from long-term experimental data is widely used to estimate surface runoff from gaged or ungauged watersheds. Many modelers have used the documented SCS-CN parameters without calibration, sometimes resulting in significant errors in estimating surface runoff. Several methods for regionalization of SCS-CN parameters were evaluated. The regionalization methods include: (1) average; (2) land use area weighted average; (3) hydrologic soil group area weighted average; (4) area combined land use and hydrologic soil group weighted average; (5) spatial nearest neighbor; (6) inverse distance weighted average; and (7) global calibration method, and model performance for each method was evaluated with application to 14 watersheds located in Indiana. Eight watersheds were used for calibration and six watersheds for validation. For the validation results, the spatial nearest neighbor method provided the highest average Nash-Sutcliffe (NS) value at 0.58 for six watersheds but it included the lowest NS value and variance of NS values of this method was the highest. The global calibration method provided the second highest average NS value at 0.56 with low variation of NS values. Although the spatial nearest neighbor method provided the highest average NS value, this method was not statistically different than other methods. However, the global calibration method was significantly different than other methods except the spatial nearest neighbor method. Therefore, we conclude that the global calibration method is appropriate to regionalize SCS-CN parameters for ungauged watersheds.

1 October 2015 in Materials
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Journal Article
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JHJae-Woong Han
Jae-Woong Han
JJJi-Hong Jeon
Ji-Hong Jeon
CPChan-Gi Park
Chan-Gi Park
We evaluated the strength and durability characteristics of latex-polymer-modified, pre-packed pavement repair concrete (LMPPRC) with a rapid-set binder. The rapid-set binder was a mixture of rapid-set cement and silica sand, where the fluidity was controlled using a latex polymer. The resulting mix exhibited a compressive strength of ¥21 MPa and a flexural strength of ¥3.5 MPa after 4 h of curing (i.e., the traffic opening term for emergency repairs of pavement). The ratio of latex polymer to rapid-set binder material was varied through 0.40, 0.33, 0.29, and 0.25. Mechanical characterization revealed that the mechanical performance, permeability, and impact resistance increased as the ratio of latex polymer to rapid-set binder decreased. The mixture exhibited a compressive strength of ¥21 MPa after 4 h when the ratio of latex polymer to rapid-set binder material was ¤0.29. The mixture exhibited a flexural strength of ¥3.5 MPa after 4 h when the ratio of latex polymer to rapid-set binder material was ¤0.33. The permeability resistance to chloride ions satisfied 2000 C after 7 days of curing for all ratios. The ratio of latex polymer to rapid-set binder material that satisfied all conditions for emergency pavement repair was ¤0.29.

17 July 2014 in Water
Verified
Journal Article
Open access
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YKYoung-Jin Kim
Young-Jin Kim
HKHae-Do Kim
Hae-Do Kim
JJJi-Hong Jeon
Ji-Hong Jeon
The HSPF-Paddy model was applied to the Bochung watershed in Korea to compare water budget components by the land use types under the Asian monsoon climate. The calibration of HSPF-Paddy during 1992–2001 with PEST, a package program to optimize HSPF, and validation during 1985–1991 were carried out. The model efficiencies for monthly stream flow are 0.85 for calibration and 0.84 for validation. The simulation of annual mean runoff met the criteria of water budget analysis with the acceptable error level (less than 10 percent mean error). The simulation of the movement of water from paddy rice field to watershed was successful, and application of HSPF-Paddy coupled with PEST was able to improve accuracy of model simulation with reduced time and efforts for model calibration. The results of water budget analysis show that most of the outflow (86%) for the urban area occurred through surface runoff, showing the highest rate among the land use types compared. Significant amounts of water are irrigated to paddy rice fields, and the runoff depth as well as evapotranspiration from paddy rice field is higher than other land use types. Hydrological characteristic of paddy rice field is that most of water movement occurred at the surface area, resulting from the low infiltration rate and manning’s coefficient, as well as ponded water throughout the growing season. Major impact on input and output of water were precipitation and runoff, respectively, influenced by an Asian monsoon climate.

29 July 2015 in Sustainability
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Journal Article
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JJJi-Hong Jeon
Ji-Hong Jeon
CPChan-Gi Park
Chan-Gi Park
BEBernard Engel
Bernard Engel
Lake Tenkiller located in Oklahoma, USA is a large midcontinent reservoir in a eutrophic state due to excess phosphorus (P) loads. Poultry waste application within the Illinois River Watershed in northeast Oklahoma and northwest Arkansas has been identified as a major contributor to overall P loads within Lake Tenkiller. In this study, Groundwater Loading Effects of Agricultural Management Systems (GLEAMS) was applied to evaluate the effect of poultry waste application on P loads to Lake Tenkiller. Historical P loads to Lake Tenkiller during 1951–2000 have increased from approximately 166,000 kg/year to more than 295,000 kg/year with the Illinois River at Tahlequah subwatershed increasing from 68% to 78% of total P loads over that period. Increased poultry waste application based on poultry growth rates could increase P load to Lake Tenkiller from 311,000 kg/year to more than 528,000 kg/year. Cessation of poultry waste application and addition of buffers along streams could reduce P loads to approximately 92,000 kg/year for cessation of poultry waste application alone and about 89,000 kg/year for cessation of poultry waste application with buffers. One possible strategy to reduce P load to Lake Tenkiller is to cease applying poultry waste application, especially in the portion of the Illinois River above the Tahlequah USGS gage station.