• Journal of Korean Society of Environmental Engineers
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• v.32 no.10
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• pp.916-927
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• 2010

In general water treatment process, the disinfection process by chlorine is used to prevent water borne disease and microbial regrowth in water distribution system. Because chlorines were reacted with organic matter, carcinogens such as disinfection by-products (DBPs) were produced in drinking water. Therefore, a suitable injection of chlorine is need to decrease DBPs. Rechlorination in water pipelines or reservoirs are recently increased to secure the residual chlorine in the end of water pipelines. EPANET 2.0 developed by the U.S. Environmental Protection Agency (EPA) is used to compute the optimal chlorine injection in water treatment plant and to predict the dosage of rechlorination into water distribution system. The bulk decay constant ($k_{bulk}$) was drawn by bottle test and the wall decay constant ($k_{wall}$) was derived from using systermatic analysis method for water quality modeling in target region. In order to predict water quality based on hydraulic analysis model, residual chlorine concentration was forecasted in water distribution system. The formation of DBPs such as trihalomethanes (THMs) was verified with chlorine dosage in lab-scale test. The bulk decay constant ($k_{bulk}$) was rapidly decreased with increasing temperature in the early time. In the case of 25 degrees celsius, the bulk decay constant ($k_{bulk}$) decreased over half after 25 hours later. In this study, there were able to calculate about optimal rechlorine dosage and select on profitable sites in the network map.

• Korean Journal of Environmental Biology
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• v.25 no.2
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• pp.168-177
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• 2007

By using DEM and digital actual vegetation map with MGE GIS software program, topographic features (altitude, slope, latitude, etc.) quantitatively were analysed and their data integrated as the index of climatic conditions (WI, CI, air temperature, etc.) in South Korea. Warmth Index (WI) decreases $5.27^{\circ}C{\cdot}month$ with latitudinal $1^{\circ} degree, and $3.41^{\circ}C{\cdot}month$ with attitudinal 100 m increase. The relationship between CI and WI values is expressed as a linear regression, $WI=116.01+0.96{\times}CI,\;R^2=0.996$. The distributional peaks of different plant communities along Warmth Index gradient showed the sequence of Abies nephrolepis, Taxus cuspidata, Abies koreana, Quercus mongolica, Carpinus laxiflora, Q. dentata, C. tschonoskii, Q. serrate, Pinus densiflora, Q. aliena, Q. variabilis, Q. acutissima, P. thunbergii, Q. acute, Castanopsis cuspidata var. sieboldii, Camellia japonica, Machilus thunbergii community from lower to higher values. The Quercus mongolica forest occurred frequently on E-NW and SE slope aspect within WI $70{\sim}80^{\circ}C{\cdot}month$ optimal range at mesic sites, NW and SE slope than xeric sites S and SW slope. The Q. serrata forest showed the most distributional frequency in NW and W slope aspect within WI $90{\sim}100^{\circ}C{\cdot}month$ range, Q. variabilis and Q. acutissima forest showed the high frequency of distribution in SE slope in WI $95{\sim}100^{\circ}C{\cdot}month$ range. By the slope gradient analysis, five groups were found: 1. Abies nephrolepis, Machilus thunbergii, 2. Taxus cuspidata, Abies koreana, Quercus mongolica, Q. dentata, Q. serrata, Q. variabilis, Castanopsis cuspidata var. sieboldii 3. Pinus densiflora, Q. aliena, Q. acutissima, P. thunbergii, Q. acuta 4. Carpinus laxiflora, Camellia japonica 5. C. tschonoskii from steep slope to gentle slope sequence.

• Economic and Environmental Geology
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• v.52 no.5
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• pp.395-407
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• 2019

The duplex system has been considered as an important slip-transfer mechanism to evaluate the evolution of orogenic belts. Duplexes are generally found in the hinterland portion of fold-thrust belts and accommodate large amounts of total shortening. Thus, understanding its geometric and kinematic evolution can give information to evaluate the evolution of the entire orogenic belt. Duplexes are recognized as closed-loop thrust traces on map view, indicating higher connectivity than imbricate fans. As originally defined, a duplex is an array of thrust horses which are surrounded by thrust faults including the floor and roof thrusts, and imbricate faults between them. Duplexes can accommodate regional layer-parallel shortening and transfer slip from a floor thrust to a roof thrust. However, an imbricate fault is not the only mean for layer-parallel shortening (LPS) and displacement transfer within duplexes. LPS cleavages and detachment folds can also play the same role. From this aspect, a duplex can be divided into three types; 1) fault duplex, 2) cleavage duplex and 3) fold duplex. Fault duplex can further be subdivided into the Boyer-type duplex, which was firstly designed duplex system in the 1980s that widely applied most of the major fold-thrust belts in the world, and connecting splay duplex, which has different time order in the emplacement of horses from those of the Boyer-type. On the contrary, the cleavage and fold duplexes are newly defined types based on some selected examples. In the Korean Peninsula, the Yeongwol area, the western part of the Taebaeksan Zone of the Okcheon Belt, gives an excellent natural laboratory to study the structural geometry and kinematics of the closed-loops by thrust fault traces in terms of a duplex system. In the previous study, the Yeongwol thrust system was interpreted by alternative duplex models; a Boyer-type hinterland-dipping duplex vs. a combination of major imbricate thrusts and their connecting splays. Although the high angled beds and thrusts as well as different stratigraphic packages within the horses of the Yeongwol duplex system may prefer the later complicate model, currently, we cannot choose one simple answer between the models because of the lack of direct field evidence and time information. Therefore, further researches on the structural field investigations and geochronological analyses in the Yeongwol and adjacent areas should be carried out to test the possibility of applying the fold and cleavage duplex models to the Yeongwol thrust system, and it will eventually provide clues to solve the enigma of formation and its evolution of the Okcheon Belt.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.2
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• pp.59-65
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• 2005

This study was performed to estimate the soil loss on a national scale and grade regions with the potential risk of soil erosion. Universal soil loss equation (USLE) for rainfall and runoff erosivity factors (R), cover management factors (C) and support practice factors (P) and revised USLE for soil erodibility factors (K) and topographic factors (LS) were used. To estimate the soil loss, the whole nation was divided into 21,337 groups according to city county, soil phase and land use type. The R factors were high in the southern coast of Gyeongnam and Jeonnam and part of the western coast of Gyeonggi and low in the inland and eastern coast of Gyeongbuk. The K factors were higher in the regions located on the lower streams of rivers and the plain lands of the western coast of Chungnam and Jeonbuk. The average slope of upland areas in Pyeongchang-gun was the steepest of 30.1%. The foot-slope areas from the Taebaek Mountains to the Sobaek Mountains had steep uplands. Total soil loss of Korea was estimated as $50{\times}10^6Mg$ in 2004. The potential risk of soil erosion in upland was the severest in Gyeongnam and the amount of soil erosion was the greatest in Jeonnam. The regions in which annual soil loss was estimated over $50Mg\;ha^{-1}$ were graded as "the very severe" and their acreage was $168{\times}10^3ha$ in 2004. The soil erosion maps of city/county of Korea were made based on digital soil maps with 1:25,000 scale.

• Korean Journal of Heritage: History & Science
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• v.54 no.4
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• pp.174-191
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• 2021

Gangdo (江都), a reproduction of Gaegyeong, was the capital of Goryeo for 39 years. However, due to the urgent wartime situation of the Mongol invasion and the geographical features of Ganghwa Island, the castle system and palace layout were somewhat different from those of Gaegyeong. Gangdo's castle can be understood as a triple castle system consisting of outer castle, middle castle, and inner castle. First, the outer castle was the first to be completed, and it was built at the forefront to prevent the Mongol army from invading in the first place. It is presumed that the section was between Huamdon and Hwadodon in the outer castle during the Joseon Dynasty. The middle castle can be seen as the present 'Middle Castle', a castle built of earth on the outskirts of the Ganghwa-mountain Castle. Considering the sophistication and robustness of the construction method confirmed in the archaeological research, this castle is thought to have been built under a meticulous plan. In other words, as the capital city, it was completed 'at last' as recorded in the Koryo History, after a long 18-year construction process to protect palaces, government offices, and private houses. The inner castle was a castle with the character of a palace. This corresponds to the Old Castle of Ganghwabu (江華府) during the Joseon Dynasty, and it almost coincided with the scale of the composition of Gaegyeong's palace castle. It was a complex functional space, featuring the integration of the palace and the imperial castle, where the main government offices and ancillary facilities, including the palace, were located. Based on the documentary record that these palaces were similar to Gaegyeong's palace, the palace map was overlapped with that of Gaegyeong. The central axis of the building from Seungpyeongmun (昇平門) to Seongyeongjeon (宣慶殿) coincided with Kim Sangyongsunjeol Monument in Ganghwa- Goryeo Palace. Therefore, it seems that the palace of Gangdo had the same basic structure as that of Gaegyeong. However, the inner palace and annexed buildings must have been arranged in consideration of the topographical conditions of Ganghwa, and this is estimated to be the Gunggol area in Gwancheong-ri.

• Korean Journal of Remote Sensing
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• v.37 no.5_2
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• pp.1329-1340
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• 2021

The intertidal zone, which is a transitional zone between the ocean and the land, requires continuous monitoring as various changes occur rapidly due to artificial activity and natural disturbance. Monitoring of coastal topography changes using remote sensing method is evaluated to be effective in overcoming the limitations of intertidal zone accessibility and observing long-term topographic changes in intertidal zone. Most of the existing coastal topographic monitoring studies using remote sensing were conducted through high spatial resolution images such as Landsat and Sentinel. This study extracted the waterline using the NDWI from the GOCI-II (Geostationary Ocean Color Satellite-II) data, identified the changes in the intertidal area in Gyeonggi Bay according to various tidal heights, and examined the utility of DEM generation and topography altitude change observation over a short period of time. GOCI-II (249 scenes), Sentinel-2A/B (39 scenes), Landsat 8 OLI (7 scenes) images were obtained around Gyeonggi Bay from October 8, 2020 to August 16, 2021. If generating intertidal area DEM, Sentinel and Landsat images required at least 3 months to 1 year of data collection, but the GOCI-II satellite was able to generate intertidal area DEM in Gyeonggi Bay using only one day of data according to tidal heights, and the topography altitude was also observed through exposure frequency. When observing coastal topography changes using the GOCI-II satellite, it would be a good idea to detect topography changes early through a short cycle and to accurately interpolate and utilize insufficient spatial resolutions using multi-remote sensing data of high resolution. Based on the above results, it is expected that it will be possible to quickly provide information necessary for the latest topographic map and coastal management of the Korean Peninsula by expanding the research area and developing technologies that can be automatically analyzed and detected.

• Korean Journal of Remote Sensing
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• v.37 no.6_2
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• pp.1819-1827
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• 2021

Land-use/cover change caused by rapid urbanization in South Korea is one of the concerns in flood risk management because groundwater recharge by precipitation hardly occurs due to an increase in impermeable surfaces in urban areas. This study investigated the hydrologic effects of land-use/cover on groundwater recharge in the Yeonje-gu district of Busan, South Korea. A statistical time series analysis was conducted with temporal variations of precipitation and groundwater level to estimate lag-time based on correlation coefficients calculated from auto-correlation function (ACF), cross-correlation function (CCF), and moving average (MA) at five sites. Landform and land-use/cover within 250 m radius of the monitoring wells(GW01, GW02, GW03, GW04, and GW05) at five sites were identified by land cover and digital map using Arc-GIS software. Long lag-times (CCF: 42-71 days and MA: 148-161 days) were calculated at the sites covered by mainly impermeable surfaces(GW01, GW03, and GW05) while short lag-times(CCF: 4 days and MA: 67 days) were calculated at GW04 consisting of mainly permeable surfaces. The results suggest that lag-time would be one of the good indicators to evaluate the effects of land-use/cover on estimating groundwater recharge. The results of this study also provide guidance on the application of statistical time series analysis to environmentally important issues on creating an urban green space for natural groundwater recharge from precipitation in the city and developing a management plan for hydrological disaster prevention.

• The Korean Journal of Archival Studies
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• no.13
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• pp.179-203
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• 2006

This study develops the process and method of official administration documents which have remained ill-balanced like the official documents of the government-general of Chosun(the pro-Japanese colonial government (1910-1945)). At first, the existing Appraisal-theories are recomposed. The Appraisal-Theories of Schellenberg is focused valuation about value of records itself, but fuction-Appraisal theory is attached importance to operational activities which take the record into action. But given that the record is a re-presentation of operational activities, the both are the same on the philosophy aspect. Therefore, in the case that the process - method is properly designed, it can be possible to use a composite type between operational activities and records. Also, a method of the Curve has its strong points in the macro and balanced aspect while the Absolute has it's strength in the micro aspect, so that chances are that both alternate methodologies are applied to the study. Hereby, the existing Appraisal theories are concluded to be the mutually-complemented things that can be easily put together into various forms according to the characteristics of an object and its situation, in the terms of the specific Appraisal methodology. Especially, in the case of this article dealing with the imbalance remains official-documents, it is necessary to compromise more properly process with a indicated useful method than establishing a method and process by choosing the only one theory. In order to appraise the official-documents of the pro-Japanese colonial government (1910-1945), a macro appraisal of value has to be appraised about them by understanding a system, functions and using the historical-cultural evolution, after analysing Disposal Authority. From this, map the record so that organization function maps are constructed regarding the value rank of functions and detailed-functions. After this, establish the appraisal strategy considering the internal environment of archival agencies and based on micro appraisal to a great quantity of records remained and supplying other meaning to a small quantity of records remained for example, the oral resources production are accomplished. The study has not yet reached the following aspects ; a function analysis, historical decoding techniques, a curve valuation of the record, the official gazette of the government general of Chosun( the pro-Japanese government for 1910-1945), an analysis method of the other historical materials and it's process, presentation of appraisal output image. As the result, that's just simply a proposal and we should fill in the above-mentioned shortages of the study through development of all the up-coming studies.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.3
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• pp.175-186
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• 2019

Efforts have been made to introduce the climate smart agriculture (CSA) for adaptation to future climate conditions, which would require collection and management of site specific meteorological data. The objectives of this study were to identify requirements for construction of agricultural meteorology information service system (AMISS) using technologies that lead to the fourth industrial revolution, e.g., internet of things (IoT), artificial intelligence, and cloud computing. The IoT sensors that require low cost and low operating current would be useful to organize wireless sensor network (WSN) for collection and analysis of weather measurement data, which would help assessment of productivity for an agricultural ecosystem. It would be recommended to extend the spatial extent of the WSN to a rural community, which would benefit a greater number of farms. It is preferred to create the big data for agricultural meteorology in order to produce and evaluate the site specific data in rural areas. The digital climate map can be improved using artificial intelligence such as deep neural networks. Furthermore, cloud computing and fog computing would help reduce costs and enhance the user experience of the AMISS. In addition, it would be advantageous to combine environmental data and farm management data, e.g., price data for the produce of interest. It would also be needed to develop a mobile application whose user interface could meet the needs of stakeholders. These fourth industrial revolution technologies would facilitate the development of the AMISS and wide application of the CSA.

• Journal of Korea Water Resources Association
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• v.52 no.5
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• pp.361-372
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• 2019

The purpose of this study is to develop a two-dimensional land surface flood analysis model based on uniform square grid using the governing equations except for the convective acceleration term in the momentum equation. Finite volume method and implicit method were applied to spatial and temporal discretization. In order to reduce the execution time of the model, parallel computation techniques using CPU were applied. To verify the developed model, the model was compared with the analytical solution and the behavior of the model was evaluated through numerical experiments in the virtual domain. In addition, inundation analyzes were performed at different spatial resolutions for the domestic Janghowon area and the Sebou river area in Morocco, and the results were compared with the analysis results using the CAESER-LISFLOOD (CLF) model. In model verification, simulation results were well matched with the analytical solution, and the flow analyses in the virtual domain were also evaluated to be reasonable. The results of inundation simulations in the Janghowon and the Sebou river area by this study and CLF model were similar with each other and for Janghowon area, the simulation result was also similar to the flooding area of flood hazard map. The different parts in the simulation results of this study and the CLF model were compared and evaluated for each case. The results of this study suggest that the model proposed in this study can simulate the flooding well in the floodplain. However, in case of flood analysis using the model presented in this study, the characteristics and limitations of the model by domain composition method, governing equation and numerical method should be fully considered.