• Title, Summary, Keyword: reduced overflow

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Analysis on the Effects of Flood Damage Mitigation according to Installation of Underground Storage Facility (지하저류조 설치에 따른 침수피해 저감효과 분석)

  • Kim, Young Joo;Han, Kun Yeun;Cho, Wan Hee
    • Journal of The Korean Society of Civil Engineers
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    • v.30 no.1B
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    • pp.41-51
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    • 2010
  • In this study, runoff simulation was carried out in the area of Bisan 7-dong, Seo-gu, Daegu as drainage basin and the effects of the installation of underground storage facilities were analyzed during heavy rainfall. SWMM model was used for the runoff and pipe network analysis on Typhoon Maemi, 2003. 2-D inundation analysis model based on diffusion wave was employed for inundation analysis and to verify computed inundation areas with observed inundation trace map. The simulation results agree with observed in terms of inundation area and depth. Also, the effects of flood damage mitigation were analyzed through the overflow discharge and 2-D inundation analysis, depending upon whether the underground storage facility is installed or not. When the underground storage facility ($W:120m{\times}L:180m{\times}H:1.7m$) is installed, volume of overflow could be reduced by 72% and flooding area could be reduced by 40.1%. When the underground storage facility ($W:120m{\times}L:180 m{\times}H:2.0m$) is installed, volume of overflow could be reduced by 84.8% and flooding area could be reduced by 50.6%. When the underground storage facility ($W:120m{\times}L:180m{\times}H:2.2m$) is installed, volume of overflow could be reduced by 94% and flooding area could be reduced by 91.2%. There is no overflow of manhole, when the height of storage facility is 2.5 m. It is expected that the study results presented through quantitative analysis on the effects of underground facilities can be used as base data for socially and economically effective installation of underground facilities to prevent flood damage.

A study on the overload control of the ATM switching system (ATM 교환기 과부하제어 연구)

  • 기장근;최진규;김영선
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.21 no.4
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    • pp.952-960
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    • 1996
  • In this paper, a new overload control scheme is proposed for a control system in ATM switching system. The proposed control scheme includes a counter that conunts the number of accepted calls and is decreased at cach D time interval. In overload condition of call processor, the control scheme detects over load condition when the counter value reaches a certain threshold value. Under overload condition, processor utilization is measured and the value of the D is updataed according to the difference between measured processor utilization and target utilization. A new call is accepted accepted only if the value of the counter is less than the threshold value. In overflow condition of cell traffic, accept probability of new call is reduced exponetially according to the elapsed time. The results of simulation show that the proposed overload contorl scheme maintains the target utilization very well under the various processor overload conditions and reduces the cell loss probability under the cell overflow conditions.

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An Efficient Simulation of Discrete Time Queueing Systems with Markov-modulated Arrival Processes (MMAP 이산시간 큐잉 시스템의 속산 시뮬레이션)

  • Kook Kwang-Ho;Kang Sungyeol
    • Journal of the Korea Society for Simulation
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    • v.13 no.3
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    • pp.1-10
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    • 2004
  • The cell loss probability required in the ATM network is in the range of 10$^{-9}$ ∼10$^{-12}$ . If Monte Carlo simulation is used to analyze the performance of the ATM node, an enormous amount of computer time is required. To obtain large speed-up factors, importance sampling may be used. Since the Markov-modulated processes have been used to model various high-speed network traffic sources, we consider discrete time single server queueing systems with Markov-modulated arrival processes which can be used to model an ATM node. We apply importance sampling based on the Large Deviation Theory for the performance evaluation of, MMBP/D/1/K, ∑MMBP/D/1/K, and two stage tandem queueing networks with Markov-modulated arrival processes and deterministic service times. The simulation results show that the buffer overflow probabilities obtained by the importance sampling are very close to those obtained by the Monte Carlo simulation and the computer time can be reduced drastically.

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Development of Vehicle Queue Length Estimation Model Using Deep Learning (딥러닝을 활용한 차량대기길이 추정모형 개발)

  • Lee, Yong-Ju;Hwang, Jae-Seong;Kim, Soo-Hee;Lee, Choul-Ki
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.17 no.2
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    • pp.39-57
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    • 2018
  • The purpose of this study was to construct an artificial intelligence model that learns and estimates the relationship between vehicle queue length and link travel time in urban areas. The vehicle queue length estimation model is modeled by three models. First of all, classify whether vehicle queue is a link overflow and estimate the vehicle queue length in the link overflow and non-overflow situations. Deep learning model is implemented as Tensorflow. All models are based DNN structure, and network structure which shows minimum error after learning and testing is selected by diversifying hidden layer and node number. The accuracy of the vehicle queue link overflow classification model was 98%, and the error of the vehicle queue estimation model in case of non-overflow and overflow situation was less than 15% and less than 5%, respectively. The average error per link was about 12%. Compared with the detecting data-based method, the error was reduced by about 39%.

Effect and Control of the Sediment in the Combined Sewer on CSOs (합류식 하수관거내 퇴적물이 CSOs에 미치는 영향 및 제어방안)

  • Lim, Bongsu;Kim, Doyoung;Lee, Kuangchun
    • Journal of Korean Society on Water Environment
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    • v.27 no.1
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    • pp.36-43
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    • 2011
  • This study is selected two points of combined sewer that occurred Fish Kill after first flush, that analyzed generation of pollutants and stream runoff generation of combined sewer overflows (CSOs) as fine weather and rainfall. In addition, this study was to analyze the relationship between CSOs and sediments, to propose measures to reduce the sediment relevant with CSOs and rainfall runoff from entering sewage treatment plants and measures for discharged directly into streams when indicate relatively good water quality after overflow. Sediments in combined sewer system was discharged about 50~80% as overflows during rainfall and we can reduce the amount of the CSOs at least 50% or more if the sewer does not exist in the sediments because of the amount of discharge about the amount of intercept has been investigated by 3~5 times. Because of velocity at sediment interval in sewer is very low, sewage velocity of about 3~5 times as much as it can increase the amount of sediment can be reduced if the separation wall is installed. Effective control of BOD overflow load is respectively 77.5%, 75.8% at first point, second point by the separation wall is installed. Drainage area greater than area in this study or many combined sewer overflows region is increased the more effective control of separation wall. Turbidity to measure changes in water quality of overflows can be used as an factor to control the intercept flows because the intercept flows(3Q) after the first flush has lowered removal efficiency and increases the operational load of sewage treatment plants. Sewage water quality after a overflow when the reasonable turbidity was measured at this point flows to excluded intercept flow(1Q) can be discharged to stream.

A Feedback Buffer Control Algorithm for H.264 Video Coding (H.264 동영상 부호기를 위한 Feedback 버퍼 제어 방식)

  • Son Nam Rye;Lee Guee Sang
    • The KIPS Transactions:PartB
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    • v.11B no.6
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    • pp.625-632
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    • 2004
  • Since the H.264 encoding adopts both forward prediction and hi-direction prediction modes and exploits Variable Length Coding(VLC), the amount of data generated from video encoder varies as Flaying time goes by. The fixed bit rate encoding system which has limited transmission channel capacity uses a buffer to control output bitstream It's necessary to control the bitstream to maintain within manageable range so as to protect buffer from overflow or underflow. With existing bit amount control algorithms, the $\lambda_{MODE}$ which is relationship between distortion value and quantization parameter often excesses normal value to end up with video error. This paper proposes an algorithm to protect buffer from overflow or underflow by introducing a new quantization parameter against distortion value of H.264 video data. The test results of 6 exemplary data show that the proposed algorithm has the same PSNR as and up to 8% reduced bit rate against existing algorithms.

Calculation of Blocking Probabilities in the Multi-slot Connection Traffic (다원 트래픽의 호손율 계산)

  • Kim, Seung-Hwan;Sung, Dan-Keun;Kim, Dae-Young
    • Proceedings of the KIEE Conference
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    • pp.958-961
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    • 1987
  • Four computational algorithms are discussed and compared which calculate the blocking probabilities in the multi-slot connection traffic for the wide-band services. The computational complexity and time can be significantly reduced, and the overflow and underflow problem can be circumvented as well, by a newly proposed algorithm, the last one.

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An Analysis of Rainwater Overflow by Housing Development and Overflow Decrease Method - Focused on the 13, 14 Districts (Motjarigol) of the Eun-pyung New Town in Seoul - (단지 개발로 인한 우수 유출량 변화 예측 및 저감방안에 관한 연구 - 서울 은평뉴타운 13, 14단지(못자리골)를 중심으로 -)

  • Sung, Jong-Sang;Lee, Eun-Seok;Kim, Dae-Hee
    • Journal of the Korean Institute of Landscape Architecture
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    • v.34 no.4
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    • pp.116-128
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    • 2006
  • This study focuses on hydrological changes caused by developments in the 13th, 14th (Motjarigol) district in Eun Pyoung New Town, Seoul on the basis of the Land Use Planning of development plan. Through analyses from the hydrological experiments about rainfall outflow using universal equation and amounts of infiltration through soils, the changes in amounts of overflows were estimated and the results were discussed from a urban ecological point of view. As a result, it has been predicted that the amount of rainfall outflow at post-development was dramatically increased, compared to pre-development. Installing of Derbris Dams and infiltration facilities were suggested as alternative plan to meditigate these changes. If we apply these alternatives, the rainfall outflow would be reduced up to 30% compared to the development plan without BMPs (Best Management Practice). In conclusion, it is proposed that once the ecological principles were considered during development planning process, we can minimize the adverse effects of developments to our environments.

Improvement of Cooling Water Quality by Coagulation and Sedimentation in Steel Mill (응집침전에 의한 제철공장 냉각수질향상)

  • Jo, Kwan-Hyung;Woo, Dal-Sik;Hwang, Byung-Gi;Lee, Seon-Ju;Park, Duck-Weon
    • Journal of Environmental Health Sciences
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    • v.35 no.5
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    • pp.411-416
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    • 2009
  • This study was initiated to improve the cooling water quality by chemical coagulation and sedimentation in steel mills. Due to the inefficient flocculation in the settling tanks of blast furnace cooling water systems, the solid particles in the cooling water overflow accumulate and clog the cooling system. To protect the cooling water system from such fouling, proper flocculants must be continuously used. Laboratory tests were performed for the indirect cooling water system of a plate mill. The batch test in the gas scrubbing cooling water system of a blast furnace showed that the proposed coagulant was more effective for the improvement of coagulation and sedimentation than the existing one. During the tests, cationic flocculants were more effective than use of only an anionic flocculant. The suggested combination of anionic and cationic flocculants can probably improve the turbidity removal efficiency of the cooling water. Proper control of the overflow rate by the designed residence time would help turbidity removal efficiency in the settling tank. In addition, the settling can be enhanced by adopting rapid and slow mixing alternatively. Scale problems in blast furnace cooling water system were reduced to some extent by efficient settling.

Determination of Optimal Operation Water Level of Rain Water Pump Station using Optimization Technique (최적화 기법을 이용한 빗물펌프장 최적 운영수위 결정)

  • Sim, Kyu-Bum;Yoo, Do-Guen;Kim, Eung-Seok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.7
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    • pp.337-342
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    • 2018
  • A rain water pumping station is a structural countermeasure to inland flooding of domestic water generated in a urban watershed. In this study, the optimal operation water level of the pump with the minimum overflow was determined based on the opinions of the person in charge of the operation of the rain water pump station. A GA (Genetic Algorithm), which is an optimization technique, was used to estimate the optimal operation water level of the rain water pump station and was linked with SWMM (Ver.5.1) DLL, which is a rainfall-runoff model of an urban watershed. Considering the time required to maximize the efficiency of the pump, the optimal operating water level was estimated. As a result, the overall water level decreased at a lower operating water level than the existing water level. For most pumps, the lowest operating water level was selected for the operating range of each pump unit. The operation of the initial pump could reduce the amount of overflow, and there was no change in the overflow reduction, even after changing the operation condition of the pump. Internal water flooding reduction was calculated to be 1%~2%, and the overflow occurring in the downstream area was reduced. The operating point of the pump was judged to be an effective operation from a mechanical and practical point of view. A consideration of the operating conditions of the pump in future, will be helpful for improving the efficiency of the pump and to reducing inland flooding.