In this study, a model to optimize residual chlorine concentrations in a water supply system was developed using a multi-objective genetic algorithm. Moreover, to quantify the effects of optimized residual chlorine concentration management and to consider customer service requirements, this study developed indices to quantify the spatial and temporal distributions of residual chlorine concentration. Based on the results, the most economical operational method to manage booster chlorination was derived, which would supply water that satisfies the service level required by consumers, as well as the cost-effectiveness and operation requirements relevant to the service providers. A simulation model was then created based on an actual water supply system (i.e., the Multi-regional Water Supply W in Korea). Simulated optimizations were successful, evidencing that it is possible to meet the residual chlorine concentration demanded by consumers at a low cost.

This research proposes an optimal flushing operation technique in an effort to prevent secondary water pollutions and accidents in aged pipes, and to improve the cleaning effect of unidirectional flushing. Water flow directions were analyzed using EPANET 2.0, while flushing and air scouring experiments in forward and reverse directions were performed in the field. In 42 experiments, average residual chlorine concentration and turbidity were improved after cleaning compared to before cleaning. It was found that even when the same cleaning method was used, further improvement of cleaning effect was possible by applying air injection and reverse direction cleaning techniques. By means of one-way ANOVA(Analysis of variance), it was also possible to statistically verify the need of actively utilizing air injection and reverse direction cleaning. Based on correlation between turbidity and TSS, the total amount of suspended solids removal was estimated for 874 flushing operations and 194 air scouring operations. The result showed that air scouring used more discharge water than flushing by an average of 4.9 m3 yet with larger amounts of suspended solids removal by an average of 145.9 g. The result of analysis on turbidity values from 887 flushing operations showed low cleaning effect of unidirectional flushing for the pipes with diameters over 300 mm. In addition, the turbidity values measured during cleaning showed an increasing tendency as pipe age increased. The methodology and results of this research are expected to contribute to the efficient maintenance and improvement of water quality in water distribution networks. Follow-up research involving the measurement of water quality at regular time intervals during cleaning would allow a more accurate comparison of discharge water quality characteristics and cleaning effects between different cleaning methods. To this end, it is considered necessary to develop a standardized manual that can be used in the field and to provide relevant trainings.

본 연구는 한반도 연안 측량이 최초로 이루어진 1787년부터 국권피탈이 일어난 1910년 이전까지 한반도 인근 해역을 측량한 서양 국가가 해양지형을 인식하고 지명을 명명한 특성을 고유지명의 특징을 통해 파악하였다. 이를 위해 영국, 프랑스, 러시아, 미국에서 간행한 항해기 11권, 측량 보고서 5권, 해도 45점, 지명집 3권을 수집해 한반도 연안 해양 측량의 시·공간적 특색을 연대기적으로 정리하였다. 또한, 수집된 자료들로부터 118개의 해양지명을 추출하고 유래를 조사하여, 지명 명명 유형을 묘사, 감정평, 차용, 기념(인물, 선박, 일반명사) 등 크게 4개 유형으로 나누어 국가별·시기별 명명 유형을 분석하였다. 분석 결과 첫째, 한반도 연안 해양 측량은 1787년 프랑스를 시작으로 영국, 미국, 러시아에 의해 활발하게 이뤄졌다. 해안별로 살펴보면 동해안의 경우 러시아에 의해 상세한 탐사가 이루어졌으며, 남해안은 영국을 중심으로, 서해안은 프랑스·영국·미국 등 여러 국가에 의해 측량되었다. 둘째, 명명 유형의 경우 인물과 선박을 기념하는 사례가 각각 46개(39%), 25개(21%)로 주요 명명 유형으로 나타났으며, 뒤이어 묘사 15개(13%), 차용 13개(11%), 일반명사 기념 9개(8%), 감정평 유형 5개(4%) 순으로 나타났다. 셋째, 서양 국가는 지명 명명에 있어 기념 유형을 선호하며, 특히 러시아와 미국은 영국과 프랑스와 비교하면 기념 유형을 이용한 지명 명명이 집중되는 경향을 보였다. 넷째, 강화도 조약 이전 시기에서 강화도 조약 이후로 시간이 흐름에 따라 영국과 러시아는 해양지명의 명명 사례 수가 증가하는 경향인 반면, 프랑스, 미국은 지명의 명명 사례 수가 줄어드는 추세를 보여주었다.

This study developed prediction models of chlorine bulk decay coefficient by each condition of water quality, measuring chlorine bulk decay coefficients of the water and water quality by water purification processes. The second-reaction order of chlorine were selected as the optimal reaction order of research area because the decay of chlorine was best represented. Chlorine bulk decay coefficients of the water in conventional processes, advanced processes before rechlorination was respectively 5.9072 (mg/L)-1d-1 and 3.3974 (mg/L)-1d-1, and 1.2522 (mg/L)-1d-1 and 1.1998 (mg/L)-1d-1 after rechlorination. As a result, the reduction of organic material concentration during the retention time has greatly changed the chlorine bulk decay coefficient. All the coefficients of determination were higher than 0.8 in the developed models of the chlorine bulk decay coefficient, considering the drawn chlorine bulk decay coefficient and several parameters of water quality and statistically significant. Thus, it was judged that models that could express the actual values, properly were developed. In the meantime, the chlorine bulk decay coefficient was in proportion to the initial residual chlorine concentration and the concentration of rechlorination; however, it may greatly vary depending on rechlorination. Thus, it is judged that it is necessary to set a plan for the management of residual chlorine concentration after experimentally assessing this change, utilizing the methodology proposed in this study in the actual fields. The prediction models in this study would simulate the reduction of residual chlorine concentration according to the conditions of the operation of water purification plants and the introduction of rechlorination facilities, more reasonably considering water purification process and the time of chlorination. In addition, utilizing the prediction models, the reduction of residual chlorine concentration in the supply areas can be predicted, and it is judged that this can be utilized in setting plans for the management of residual chlorine concentration.

In this study, the leak signal was measured by using an accelerometer to analyze the basic data and methodology for the development of the leak point estimation method in the water supply pipe. The measured results were analyzed by frequency analysis and cross-correlation analysis for leakage signals, and the error range was compared and analyzed with the actual leak point distance. As a result, it was confirmed that the vibration intensity due to leakage from the water leakage point was attenuated according to the distance. In the case of the ductile iron casting used in the experiment, the intensity of the signal at the 945 Hz, 1,500 Hz, 2,300 Hz band was increased with the change of the pressure in the pipe at 4mm of leakage hole. Also, it was confirmed that as the water pressure increases, the intensity of the leak signal increases but the similarity of the signal decreases. The results of this study confirm that the accelerometer sensor can be used efficiently for leak detection and it can be used as a basic data for the analysis for the development of leak point estimation method in the future.

Most of aged water supply pipes have been replaced by the open cut method. However, this method has some limitations because water pipes, in many cases, are buried together with other underground facilities or are buried in the middle of high-traffic roads or in narrow alleyways where boring machines cannot be used. This research developed a pipe bursting device for small diameter pipes that enables pipe replacement without excavating the ground, by the busting of existing buried pipes followed by the traction and insertion of new pipes. As a results of examining the field applicability of the developed device, PE pipes and PVC pipes required the tractive force of 413.65～665.69 kgf and 457.43～791.35 kgf respectively, plus an additional 30 % tractive force per elbow. The proper number of bursting head was demonstrated that the connection of more than 2 heads could secure a stable bending radius of 15D. The developed device can be improved through field experiments involving various pipe types and pipe diameters, as well as presence/absence of elbow, so as to be utilized regardless of diverse variables according to the conditions of the soils surrounding existing pipes.

Water supply/intake pumps operation use 70~80% of power costs in water treatment plants. In the water treatment plant, seasonal and hourly differential electricity rates are applied, so proper pump scheduling can yield power cost savings. Accordingly, the purpose of this study was to develop an optimal water supply pump scheduling scheme. An optimal operation method of water supply pumps by using genetic algorithm was developed. Also, a method to minimize power cost for water supply pump operation based on pump performance derived from the thermodynamic pump efficiency measurement method was proposed. Water level constraints to provide sufficient disinfection performance in a clearwell and reservoirs were calibrated. In addition, continuous operation time constraints were calibrated to prevent frequent pump switching. As a result of optimization, savings ratios during 7 days in winter and summer were 4.5% and 5.1%, respectively. In this study, the method for optimal water pump operation was developed to secure disinfection performance in the clearwell and to save power cost. It is expected that it will be used as a more advanced optimal water pump operation method through further studies such as water demand forecasting and efficiency according to pump combination.

This study develops a model to estimate the economic life of the large-diameter water supply pipeline in Korea by supplementing existing methods used to perform similar calculations. To evaluate the developed methodology, the model was applied to the actual target area with the conveyance pipe in P waterworks. The application yielded an economic life computation of 39.7 years, considering the cost of damages, maintenance, and renewal of the pipeline. Based on a sensitivity analysis of the derived results, the most important factor influencing the economic life expectancy was the predicted failure rate. The methodology for estimating the economic life of the water supply pipeline proposed in this study is one of the core processes of basic waterworks facility management planning. Therefore, the methods and results proposed in this study may be applied to asset management planning for water service providers.

This study aimed to develop a method to optimize residual chlorine concentrations in the process of providing water supply. To this end, this study developed a model capable of optimizing the chlorine input into the clearwell in the purification plant and the optimal installation location of rechlorination facilities, and chlorine input. This study applied genetic algorithms finding the optimal point with appropriate residual chlorine concentrations and deriving a cost-optimal solution. The developed model was applied to SN purification plant supply area. As a result, it was possible to meet the target residual chlorine concentration with the minimum cost. Also, the optimal operation method in target area according to the water temperature and volume of supply was suggested. On the basis of the results, this study derived the most economical operational method of coping with water pollution in the process of providing water supply and satisfying the service level required by consumers in the aspects of cost effectiveness. It is considered possible to appropriately respond to increasing service level required by consumers in the future and to use the study results to establish an operational management plan in a short-term perspective.

In this study, a model was developed to predict for Disinfection By-Products (DBPs) generated in water supply networks and consumer premises, before and after the introduction of advanced water purification facilities. Based on two-way ANOVA, which was carried out to statistically verify the water quality difference in the water supply network according to introduce the advanced water treatment process. The water quality before and after advanced water purification was shown to have a statistically significant difference. A multiple regression model was developed to predict the concentration of DBPs in consumer premises before and after the introduction of advanced water purification facilities. The prediction model developed for the concentration of DBPs accurately simulated the actual measurements, as its coefficients of correlation with the actual measurements were all 0.88 or higher. In addition, the prediction for the period not used in the model development to verify the developed model also showed coefficients of correlation with the actual measurements of 0.96 or higher. As the prediction model developed in this study has an advantage in that the variables that compose the model are relatively simple when compared with those of models developed in previous studies, it is considered highly usable for further study and field application. The methodology proposed in this study and the study findings can be used to meet the level of consumer requirement related to DBPs and to analyze and set the service level when establishing a master plan for development of water supply, and a water supply facility asset management plan.

This study concerned the analysis on the efficiency of the conversion of water tank type supply system to direct water supply system to examine the feasibility of the conversion, as well as the calculation of optimal conversion range that enables the supply of safe, high-quality water at stable pressure in accordance with the standards of water supply facility. The results of this research showed that when converting water supply system from water tank type supply system to direct water supply system, more nodal points could be properly converted and more reduction of electricity usage was expected in case water pressure rather than residence time was fixed. This means that higher efficacy can be obtained by fixing water pressure when converting water supply system. However, since the number of the locations that received on-spot inspection was small and the electricity usage measured was not exclusively by water supply facility, it is difficult to judge that such reduction of electricity usage accurately represents reduced electricity usage by water supply facility alone. therefore, after having secured on-spot information about a larger number of locations in apartment complexes that have converted water supply system, and utilizing information about electricity usage exclusively by water supply facility, the proposed method of this research could be applied to accurately deducing expected reduction of electricity usage by water supply facilities of various other apartment complexes. It is also considered possible to deduce an effective operation method of water supply system by finding out an area that shows low pressure or low residual chlorine concentration in the optimal conversion range of water supply, followed by estimating the proper location of pumping station or the proper chlorine dosage at the power purification plant that supply water to the target area.

It is considered necessary to renewal a considerable number of water supply facilities in Korea because they began to be intensively buried in the period of rapid economic growth. Accordingly, local water providers are required to take measures against this situation, but they have currently been caught in a vicious circle of the lack of budget spent in renewing water supply facilities because county-based small-scale local water supply cannot afford to cover annual expenditures with their revenues from water rates. Therefore, this study developed an optimal renewal planning model capable of achieving a balance of financial revenue and expenditure in local water supply using nonlinear programming and furthermore of minimizing the total cost incurred during the analysis. To this end, this study selected the water supply area located in County Y as a research area to build the financial revenue and expenditure and used Solver function provided by Microsoft Excel to use nonlinear programming. As a result, this study developed an optimal renewal planning model minimizing incurred costs in consideration of 6 items in the financial revenue and expenditure. The optimal renewal plan was modeled according to the available annual budget. As a result, this study proposed SICD, a scenario to minimize total costs from the perspective of water suppliers, and SITS, a scenario to minimize the increase in water rates from the perspective of consumers. It can be said that the method proposed in this study is the core of the optimal financial and renewal plans as a final stage of asset management for water supply facilities. Therefore, it is considered possible for local water providers to use the method proposed in this study according to circumstances for the asset management of water supply facilities.

For the asset management of a water pipe network, it would be necessary to understand the extent of the maintenance cost required for the water pipe network for the future. This study would develop a method to draw the optimum cost required for the maintenance of the water pipe network in waterworks facilities to maintain the aim revenue water ratio and to achieve the target revenue water ratio, considering the water service providers’ waterworks condition and revenue water ratio comprehensively. This study conducted a survey with 96 water service providers as of the early 2015 and developed models to estimate the optimum maintenance cost of the water pipe network, considering the characteristics of the water service providers. Since the correlation coefficient of all the developed models was higher than 0.95, it turned out that it had significant reliability, which was statistically significant. As a result of applying the developed models to the actual water service providers, it was drawn that increasing revenue water ratio to more than a certain level can reduce the maintenance cost of the water pipe network by a great deal. In other words, it is judged that it would be the most efficient to secure the reliability of waterworks management by increasing the short-term revenue water ratio to more than a certain level and gradually increase the revenue water ratio from the long-term perspective. It is expected that the proposed methodology proposed in this study and the results of the study will be used as a basic research for planning the maintenance of water pipe network or establishing a plan for waterworks facilities asset management.

Owing to time and cost constraints, new methods that would make it possible to evaluate the safety of the water supply pipeline in a less time- and cost-consuming manner are urgently needed. In response to this exigency, the present study developed a new statistical model to assess the safety of the water supply pipeline using the quantification theory type Ⅱ. In this research, the safety of the water supply pipeline was defined as ‘a possibility of the pipeline failure’. Quantification analysis was conducted on the qualitative data, such as pipe material, coating, and buried condition. The results of analyses demonstrate that the hit ratio of the quantification function amounted to 77.8% of hit ratio, which was a fair value. In addition, all variables that were included in the quantification function were logically valid and demonstrated statistically significant. According to the results derived from the application of the safety evaluation model, the coefficient of determination (R2) between K-region’s water supply pipeline safety and the safety inspection amounted to 0.80. Therefore, these findings provide meaningful insight for the measured values in real applications of the model. The results of the present study can also be meaningfully used in further research on safety evaluation of pipelines, establishing of renewal prioritization, as well as asset management planning of the water supply infrastructure.

Background : Sorghum (Sorghum bicolor) is a perennial plant of the Gramineae, followed by rice, wheat, corn and barley, the fifth major food crop in the world. Sorghum is mostly used in Korea for cereals using seeds or for making food directly. However, sorghum is not directly used for food in foreign countries, but plays an important role in the development of cosmetic and pharmaceutical materials and as a bio-energy crop. Most of the sorghum cultivated in Korea does not use the remainder after harvesting seeds, so research on other uses is needed. Therefore, we carried out this experiment in order to identify the characteristics of domestic genetic resources and to select the genetic resources with excellent growth. Methods and Results : Samples were tested for their growth characteristics by the Agricultural Genetic Resources of National Institute of Agricultural Sciences. Growth characteristics of heading, total length, stem length, stem width, leaf length, leaf width, length of ears and width of ears were investigated. After 10 weeks of sowing, 45% of the outbreaks occurred and showed a quick heading. The total length of the sorghum ranged from 65.7 ㎝ to 341.0 ㎝, and the stem width ranged from 0.2 ㎝ to 2.6 ㎝. Leaf length ranged from 33.3 ㎝ to 92.4 ㎝ and leaf width ranged from 3.8 ㎝ to 12.2 ㎝. The length of the ears was in the range of 8.0 ㎝ - 52.7 ㎝, and the width of the ears was in the range of 5.2 ㎝ - 27.0 ㎝. K131301, K178840, K258654 and K255198, which are expected to bear a large number of seeds with high biomass content and large size of leaves and plants, were selected. Conclusion : Through this study, we can understand the growth characteristics of the sorghum in Korea and select excellent genetic resources.

본 연구에서는 다양한 식품유해미생물에 대한 길항작용 및 항산화활성이 우수한 B. subtilis SRCM102046 균주를 식품보존 소재로서 이용하기 위해 반응표면분석법을 이용하여 균체 증량을 통한 항균활성 및 항산화활성 증대를 도모하고자 하였다. SRCM102046의 산업적 활용을 위한 성장조건을 최적화하기 위해 배양시간에 따른 균체 성장을 조사하였으며, 통계학적 기법인 반응표면분석법을 사용하였다. SRCM102046의 최적 성장을 위한 배지 성분을 선별하기 위해 Plackett-Burman design을 이용하였으며, PBD 결과 선별된 배지 성분으로 molasses, sucrose, peptone으로 예측되었다. 각 배지 성분의 최적농도를 결정하기 위한 방법으로 central composite design을 이용하였으며, 최종적으로 예측된 각 배지 성분의 농도는 molasses 7 g/L, sucrose 7 g/L, peptone 2 g/L로 예측되었다. 이때의 균체량은 22.03±1.30 g/L로 예측되었으며, 통계분석을 통해 실험모델의 적합성을 확인하였다. 또한, 실험 모델을 수행하여 건조균체량을 측정한 결과 22.02±0.35 g/L로 측정되어 실험모델에 의해 예측된 값이 오차범위 내에 존재하여 모델의 신뢰성이 매우 높음을 확인하였으며, 이는 실험모델에 의해 예측된 최적배지 사용시 최적화 이전의 LB 배지에서의 균체량(2.47±0.03 g/L)대비 약 9배의 균체량이 증가함을 확인하였다. 또한 최적배지에서 B. subtilis SRCM102046 배양 시 항균활성은 대조구로 사용된 LB 배지에서의 항균활성 대비 최대 140% 향상되었으며, 항산화활성은 약 100.41% 증가함을 확인하였다. 본 연구를 통하여 식품보존제로서B. subtilis SRCM102046의 산업화를 위한 배지최적화를 수행하였으며, 추후 박테리오신의 정제 및 특성 등에 대한 세부적인 연구가 필요하지만 본 연구를 통해 확립된 배양조건을 기반으로 식품보존 소재의 측면에서 매우 유용한 자료로 활용될 수 있을 것으로 기대된다.

When used as a starter in the manufacture of Meju, it is expected that the quality of the soup products can be improved. In this study, we isolated Lactobacillus strain having possible safety and food-industrial benefits as a starter. Four hundred and seven isolates were screened from Meju, and chemically characterized for their antibacterial activity against Bacillus cereus, non-productivity of biogenic amine, and hemolysis. Eight of the isolates were selected upon chemical characterization, and their antioxidant and β-glucosidase activity was measured. Finally, we selected, and measured its enzyme activity and antibiotic resistance. Next, we investigated its cell growth, showed maximum biomass of 3.5 g/L after 28 h of culture. The ingredients of the medium to improve biomass were selected using the Plackett-Burman design (PBD) and central composite design (CCD). The results obtained using PBD revealed molasses, yeast extract, and maltose to be significant factors determining the biomass of the L. brevis SCML 432 strain. The CCD was then applied with three variables found from PBD and the optimum values were predicted to be 5.5% molasses, 1.5% yeast extract, and 2.0% maltose, and the maximum biomass was predicted to be 11.2 g/L. Through model verification, we confirmed that the predicted and actual results were similar, with about 3.2-fold improvement in the biomass from 3.5 g/L to 11.3 g/L when compared to that obtained in basal medium. These results suggest that SCML 432 has high potential in the food industry as a starter.

본 연구에서는 스마트빅보드 사용현황을 조사하고 분석하여 시스템 사용자 환경 개선을 도모하고자 스마트빅보드를 사용하고 있는 유관기관을 대상으로 설문조사를 실시하였다. 이를 통해 스마트빅보드 운영과 유지관리 방향을 모색하고 시스템 개선방안을 도출하고자 하였다. 설문대상 기관의 자체적 재난상황 모니터링 정보시스템 운영현황, 재난정보 활용현황, 스마트빅보드 시범운영 실태, 스마트빅보드 시범운영 보완·개선사항 등을 중심으로 조사하였다. 설문 분석결과 기관별로 자체적인 재난관련 정보시스템을 운영하면서 재난상황 발생 시 언론보도 등의 대중 매체와 중앙정부에서 제공하는 정보들을 공동 활용하고 있었다. 이는 기존의 정보시스템에서 제공하는 정보 외에도 긴박한 재난상황에서 효과적으로 대처하기 위해 새로운 정보원(source)이 필요함을 확인할 수 있었다. 또한 스마트빅보드 사용현황을 조사한 결과 응답자의 83%가 스마트빅보드를 사용한 적이 있거나 사용 중인 것으로 나타났다. 신규 정보시스템 구축에 필요한 재난정보의 콘텐츠로는 사전 징후감지와 관련된 예방 중심 정보의 중요성이 강조되었다. 이와 유사한 의견은 시스템 운영 시에도 수시로 접수되었던 내용이며, 이에 대한 기술적 검토를 통하여 시스템 고도화 사업에 적극 반영해야할 것으로 판단된다. 본격적인 설문조사에 앞서 설문자의 기본정보를 수집하는 과정에서 직무영역과 연령대를 조사하였는데 40대 이상의 업무 전담자가 69.2%로 가장 높은 비중을 차지한 것으로 조사되었다. 이에 따라 직무 관련 교육프로그램의 개발 방안도 마련되어야 할 것으로 보인다. 결론적으로 정보시스템의 기능개선 못지않게 전문운영인력 향후 중점적으로 추진해야 할 과제로 도출되었다.

과거 반복된 대형재난의 발생은 재난상황관리의 중요성을 환기시켰고, 재난상황관리를 위해서는재난현장과 상황실 간의 신속한 정보 공유와 원활한 소통이 전제되어야 함을 알게 되었다. 따라서 국립재난안전연구원에서는 2012년부터 Smart Technology와 Bigdata Technology를 융합한 통합재난상황관리 시스템인 스마트빅보드의 개발을 시작하였으며, 현재 복수의 테스트베드를 위해 지자체를 대상으로 시범 사업을 운영하고 있다. 스마트빅보드는 여러 가지 재난정보를 웹기반의 전자지도에 모아서 표출 함으써, 위험상황을 한눈에 파악하고, 재난 유형별 맞춤형 재난 상황관리를 가능하게 하는 재난상황관리 통합시스템이다. 스마트빅보드가 기존의 재난상황관리 시스템과 차별된 점은 SNS를 통해 생산되는 빅데이터와 영상스트리밍 기술이다. 빅데이터기술은 트위터로 생산되는 SNS정보를 재난관련 71가지 키워드로 분류하고 분석하여 재난에 관련된 키워드 중 급상승 하는 것을 포착하여 알람으로 표출해준다. 실제로 ‘판교추락사고’나 ‘2014 한아세안정상회담’ 당시 추락사고와 테러에 관한 키워드가 급상승하였고 이것을 알람으로 확인 할 수 있었다. 또한 CCTV가 없는 음영지역에 재난이 발생할 경우 영상스트리밍기술을 통해 재난현장의 영상을 상황실에 실시간으로 전송할 수 있으며, 양방향 TEXT 전송 기능을 이용하여 현장과 상황실 간의 소통도 가능하다. 이러한 영상스트리밍 기술은 재난현장 뿐만 아니라 안전이 우려되는 위험지역을 방문할 때에도 유용하게 사용된다. 현재 지자체를 대상으로 운영되고 있는 시범 사업의 결과는 추후 스마트빅보드 고도화 사업에 적용되어 보다 효율적으로 재난상황을 관리하는 데 도움을 줄 수 있을 것이다.