• Journal of Korean Society of Water and Wastewater
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• v.11 no.4
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• pp.91-98
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• 1997

At present, automated monitoring of water quality in Han river has been operated at each water treatment plant. But the automated measurement sites must be choosen newly because water source in Seoul move to the upper stream of Chamshil weir. In this study, automated monitoring sites in Han river were reviewed, and the proper sites for automated monitoring of water quality have been selected by Qual2E model, RMA model, water sampling guidline, Sanders' method and topograpical characteristics of Han river in order to resonable operate. 8 sites have been selected as follows: (1) the site of immediately after Paldang drainage (2) the left site and a right site of $Gu{\check{u}}i$ water intake (3) the left site and a right site at Noryangjin(Han river bridge) (4) the site between Shingok weir and Anyangchun confluence point(Hangju bridge) (5) the site of Chungryangchun downstream(existence) (6) the site of Tanchun downstream(existence) (7) the site of Anyangchun downstream(existence) (8) the site of Wangsukchun downstream. The results proposed resonable operating management of network and economical system built up.

• Journal of Korean Society on Water Environment
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• v.25 no.6
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• pp.972-978
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• 2009

This study modifies the present total maximum daily load (TMDL) system of Ministry of Environment and applies to the Anyangcheon watershed. Hydrologic Simulation Program-FORTRAN (HSPF) model is used to simulate both runoff and non-point source pollution, simultaneously, instead of QUAL2E. The drought flow (355th daily flow) is proposed for the target water quantity since it is easier to satisfy low flow (275th daily flow) for the target water quality than drought flow. The increase of discharge is more than the increase of pollutant load except for the period under low flow. The measured unit loads for non-point source are used to consider the regional runoff characteristics. The measured water quantity and quality data are used since the ministry of environment supports only water quality. This analysis results show some reasons for the improvement of the present TMDL system of Korea.

• Journal of Korean Society on Water Environment
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• v.23 no.6
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• pp.807-813
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• 2007

Settling velocity is one of major parameters determining algal biomass in water quality modeling. In this study, the settling velocity of phytoplankton was measured in reservoir and stream sites of the Nakdong River, Korea. Settling velocities of various phytoplankton species were determined by measuring algal cell biomass settled in a sedimentation cylinder. Mean settling velocities were $0.22m\;day^{-1}$ in reservoir sites and $0.33m\;day^{-1}$ in stream sites, which were relatively higher compared with other default values suggested by water quality models (e.g. $0.1m\;day^{-1}$ in CE-QUAL-W2). The lower settling velocity in reservoirs than in stream implies the adaptation of phytoplakton to low turbulence in lentic environments. Cyanobacteria showed lower settling velocity ($0.2m\;day^{-1}$) than diatoms ($0.3m\;day^{-1}$), and this phenomenon may have resulted from buoyancy mechanisms of cyanobacteria. Cell volume did not show a significant correlation with settling velocity in this study, implying that conformation factors of colonies or other factors had large effects on settling velocity of algal cells as well as cell size. The result of this study may suggest proper coefficients of settling velocity of phytoplankton in the calibration of water quality model.

• Water for future
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• v.29 no.5
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• pp.185-202
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• 1996

The newly-developed method for estimating the instream flow, proposed by the authors (1996), was applied to the main channel reach of the Kum River basin in Korea. Performance of the suggested method was tested through the evaluations of the required flow, instream flow, and river-management flow which were estimated at five main reaches with each representative station. The mean drought flow was used as the object flow to evaluate the minimum instream flow for the mid- and large-size rivers. Water quality prediction by using the QUAL2E model was made for both cases that the planned wastewater treatment facilities may and may not be constructed. The required flow for the fish habitat was evaluated for 9 representative fish species. The instream flows required for the riverine aesthetics at Kong-ju and Puyo scenary points, for river navigation at natural channel conditions, and for current and potential recreation activities were evaluated, respectively. The instream flows required for other items are not quantified. On the whole, it is shown that the instream flow to maintain the natural riverine functions such as fish habitat, and riverine aesthetics govern the upstream reaches of the Kum River, and the artificial riverine functions such as conservation of water quality, navigation and recreations govern the middle and downstream reaches. Especially, it is found that the instream flow requirement depends largely upon the construction of wastewater treatment facilities at the Kum River basin.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.3
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• pp.13-21
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• 1987

The object of this study was to evaluate the management alternatives with respect to the attainable water quality and total cost(construction+O & M cost) in order to devise a reasonable water quality management system. Joong Ryang-cheon stream located Seoul, Korea was taken as the study area, and dissolved oxygen concentration as the water quality index. Water quality simulation model QUAL2E and linear programming optimization technique were used for scientific and rational analyses. It was assumed that the improvement of water quality could be obtained by the treatment of major point sources where imaginary treatment plants were constructed. And by this, the relationship between total cost of the treatment plants and the stepwise improvement of water quality was studied. The result showed that 3.5mg/l of DO(=dissolved oxygen) level at best could be attained in Joong Ryang-cheon stream during summer. When the DO standard was set 3.0mg/l in the severely polluted regions, more than 5.0mg/l of DO level can be achieved by the construction of 4 treatment plants. Also, the cost comparisons showed that the uniform treatment method is economically inefficient(\$24.8{\times}10^8$) in comparison with the least cost method(\$22.9{\times}10^8$), and there is little difference between the least cost method and the the zoned treatment method(\$23.0{\times}10^8$) that is regarded as more equitable, which shows the characteristics of this basin.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.2
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• pp.150-160
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• 2016

The quality of service in ERP services is a key issue in innovating the ERP performance as an IT service for corporations. Currently, most of the research works for this area are based on the existing quality models such as SERVQUAL, which are said not to measure service quality properly. Also, it does not consider the factor of the system acceptance, which is thought to be closely related to the quality of service in this type of IT services. Therefore, a research model is required, which can address the issues related to the ERP service quality measurements. In this paper, new research models have been proposed, and empirical data obtained from SME's ERP users have been applied to the proposed model to analyze the causal relationship between quality factors and to identify the most suitable quality measures. Also, the relationship between the service quality and the system acceptance was analyzed using a combined model. The results show that factors such as productivity and convenience affects the quality mostly and that the most appropriate measure for the service quality of ERP service is satisfaction. Also, for the system acceptance, the ease-of-use is the main factor. And, the service quality and system acceptance shows a strong correlation. This means that, in order to enhance the quality of ERP services, the service provider needs to provide customers with productivity-enhanced user-friendly IT services and active product support. The work of this research can help to improve the service quality and the user acceptance of ERP services and to lead further research works in this area.

• Journal of Korean Society on Water Environment
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• v.30 no.1
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• pp.44-59
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• 2014

Despite the implementation of TMDL, the water quality in lower watershed of Nam river dam has worsened continuously since 2005. Multifarious pollution sources such as cities and industrial districts are scattered around it. Nam river downstream bed slope is very gentle towards the downstream water flow of slows it down even more, depending on the water quality deterioration is accelerated eutrophication occurs. In this study, the mainstream in lower watershed of Nam river dam region to target aquatic organic matter by phytoplankton growth contribution was evaluated by statistical analysis. and statistical evaluation of water quality and the accuracy of forecasting, model calibration and verification procedures by completing QUALKO2 it's eutrophic phenomena that occur frequently in the dam outflow through scenarios predict an increase in water quality management plans to present the best should.

• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.5
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• pp.62-72
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• 1995

공학분야에 널리 사용되고 있는 신뢰도 분석 방법 중에서 Monte Carlo simulation (MC), Mean-value First-Order Second-Moment Method(MFOSM), and Advanced First-Order Second-Moment(AFOSM) method들을 강물의 오염물질 농도와 수질기준치사이의 신뢰도 분석에 적용하였다. 미 환경 보건국에서 개발 보급한 QUAL2E를 이용하여 Mew Jersey에 위치한 Passaic강의 수질예측에서 4가지 주요인자(용존산소, 생물학적 산소요구량, 암모니아 그리고 조류)들이 정해진 수질기준치를 유지 할 수 있는 확률을 세가지 방법에 의해 추정한 후에 상호 비교하였다. MC방법에 의해 2,000회 simulation시켜서 그 결과가 시스템의 추계학적 성질을 잘 반영한 것으로 판단하여 비교기준으로 삼고 MFOSM과 AFOSM에 의해 추정한 결과와 비교하였다. MFOSM의 결과보다는 AFOSM의 결과가 전체적으로 MC의 결과에 더 근접하였으며, 이유는 AFOSM의 계산방법이 MFOSM의 선형근사로 인한 오차를 줄일 수 있었기 때문인 것으로 판단된다. MC방법의 결과와 다른 방법들의 결과사이의 차이가 입력 변수들이 평균값에서 멀어질 때가 많았는데 이는 MC의 경우 입력 변수들이 일정범위를 벗어나서 비현실적인 상황이면 model이 정지하는데, 다른 방법들은 simulation에 의한 것이 아니고 수학적인 계산에 의해서 신뢰도가 추정되기 때문에 이러한 상황이 반영될 수 없기 때문이다. 강물의 수질을 취급하는 공학적인 측면에서 보면, 이중에 가장 간편한 MFOSM이 많은 simulation이 필요한 MC나 계산방법이 상대적으로 복잡한 AFOSM에 비해 오차가 크지 않아서 이들을 대시하여 사용될 수 있다고 판단된다. 유래의 PAF가 분비된다는 것을 알 수 있었으며, 이러한 인자는 동결처리에서도 그 기능은 전혀 변하지 않는다고 본다. 이후에 있어서 mouse LIF의 첨가는 돼지의 수정란을 배반포 이후의 단계에까지 발달시킬 수 있었다. 있어서 더 적합한 것으로 판단되었다. 5. 개발된 모형은 논 관개의 물리적 측면과 관리목표 모두를 고려한 것으로 계산된 효율은 벼, 생육 각 단계에서의 효율 비교에 양호한 방법임을 알 수 있다.은 Sharpsburg 점질양토에 대한 S.C.S 한계허용치 10ton/ha/year 이내로 나타났다. 비처리구에서의 토양유실량은 평균 2.56ton/ha/year로 높게 나타난 반면 3개의 서로 다른 추리구인 비수구, 초생수로구 및 Bromegrass구에서는 각각 0.152, 0.192 및 0.290ton/ha/year로 낮은 결과를 가져왔다. 6. 평균 침전량에 대한 L.S.D. 검정 걸과 전시험구중 비처리구가 고도의 유의차를 나타낸 반면 비수구, 초생수로구 및 Bromegrass 목초구 간에는 아무런 유의차가 인정되지 않았다. 7. 농지보전 처리구인 배수구와 초생수로구는 비처리구에 비해 낮은 침두 유출량과 낮은 토양유실량을 나타내었다.구보다 14% 절감되는 것으로 나타났다.작용하는 것으로 사료된다.된다.정량 분석한 결과이다. 시편의 조성은 33.6 at% U, 66.4 at% O의 결과를 얻었다. 산화물 핵연료의 표면 관찰 및 정량 분석 시험시 시편 표면을 전도성 물질로 증착시키지 않고, Silver Paint 에 시편을 접착하는 방법으로도 만족한 시험 결과를 얻을 수 있었다.째, 회복기 중에 일어나는 입자들의 유입은 자기폭풍의 지속시간을 연장시키는 경향을 보이며 큰 자기폭풍일수록 현저했다. 주상에서 관측된 이러한 특성은 서브스톰 확장기 활동이 자기폭풍의 발달과 밀접한 관계가