• Korean Journal of Agricultural Science
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• v.38 no.1
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• pp.163-172
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• 2011

To provide the operation rule curve for suppling instream flow to urban stream from reservoir, the Soho reservoir with watershed area of 7.4 $km^2$ and total water storage of 2.58 $Mm^3$ was planned at the headwaters of the Daejeoncheon. Daily streamflow was simulated and using the simulated streamflow and desired instream flow, the operation rule curve by Senga method was drawn and evaluated through reservoir operation. Senga method is derived by accumulating the differences between streamflow and desired instream flow adversely. Water storages were simulated on a daily basis to supply urban instream flow from Soho reservoir, but the amount of supplying instream flow to urban stream was not nearly increased comparing with that of normal operation that does not used the rule curve. Thereafter the new simulation-based operation rule curve was derived and applied to supply instream flow from Soho reservoir. In normal operation, the amount of instream flow was shown to 15,000 $m^3$/d, but it was increased to 27,700 $m^3$/d in withdrawal limited operation using the new derived rule curve, in which the applicability of this rule curve was proved. Also comparing with the flow duration curves at station just before urban Daejeoncheon stream without and with upstream Soho reservoir, the 95th flow was decreased from 1.64 mm/d to 1.51 mm/d, and the 355th flow was increased from 0.17 mm/d to 0.30 mm/d. Monthly streamflows during October to March were increased from 10.6~24.1 mm to 24.1~34.0 mm with the increasing rate of 141~227%.

• KCID journal
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• v.18 no.1
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• pp.68-80
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• 2011

To provide a operation rule curve for reservoir with low ratio of watershed area to paddy field area, Duckyong reservoir with watershed area of $15.8km^2$ and paddy field area of 1,071ha was selected, in which 4 meters are being heightened and full water levels will be increased from EL.26.0m to EL.30.0m, total water storages from 365.6M $m^3$ to 708.0M $m^3$. There was no operation rule curve that satisfied over 90% reliability of water supply in reservoir with watershed area of 1.48 times of paddy field area. The differences between observed and simulated reservoir daily water storages were minimized to determine parameters for simulating reservoir inflow in case of paddy field area of 550ha from 1991 to 2010. A operation rule curve was drawn to have a maximum storage with total water storage, which was in paddy field area of 700ha with ratio of 2.3 between watershed area and paddy field area. This case showed that annual irrigation water supply was 668M $m^3$ and instream flow of 57M $m^3$, water supply reliability of 55.6% in normal operation, and annual irrigation water supply was 605M $m^3$ and instream flow of 38M $m^3$, water supply reliability of 95.6% in withdrawal limited operation. Water supply reliabilities showed 35.6% without flood regulation and 17.8% with flood regulation in existing reservoir before heightening.

• Journal of Korean Society for Quality Management
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• v.23 no.2
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• pp.53-67
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• 1995

The problem considered here is to find the optimal discriminant analysis method in growth curve model. It has been studied how to find correct prior probability for the effective classification in discriminant analysis. We use the balanced condition to calculate prior probability. From the informative simulation study, new classification rule for the growth curve model is suggested. The suggested classification rule has better classification result than the other previously suggested method in terms of error rate criterion.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.117-122
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• 1999

The state of drought was evaluated by the operation rule curve. From the present percentage of reservoir storage and the operation rule curve, it could be determined to ristrict the irrigation water supply to a certain level and eventually to overcome the shortage of water in the irrigation reservoir.

• Proceedings of the Korea Water Resources Association Conference
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• 1987.07a
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• pp.183-190
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• 1987

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.81-86
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• 1998

It is difficult to know how to restrict the amount of water supply in the drought season, because there is no objective standard rules. The purpose of the study is to present management rules to overcome the drought in the irrigation reservoir by forecasting the water level and restricting water supply according to the operation rule curve and the pattern of rotation-irrigation system. From the operation rule curve drawn up by analyzing the observed water level of reservoir, the water supply rules and rotation-irrigation patterns using WWW and GIS are suggested.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.30-34
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• 2007

Structural integrity of railway vehicles should last for a long period against various and continuous fatigue loadings, and the carbody structures of railway vehicle are manufactured by applying multiform welding types for each material. Since the most of cracks are occurred and proceeded at the vicinity of welding area during the lifetime of carbody structure, the fatigue strength evaluation for welding area of carbody structure should have been carried out. Rotem Company has evaluated lifetime and fatigue strength of carbody structure according to the fatigue analysis based on the international standard and/or inner-official regulation. This study introduces the fatigue analysis method that we have evaluated and calculated the damages for the welding areas of carbody structure under various fatigue loading conditions using cumulative fatigue damage rule(Miner's rule) to verify whether the cumulative damage does exceed unity. This study contains the fatigue test of specimens to derive stress-life relations(S-N curve), sub-modeling analysis and the calculation of cumulative damages under fatigue loading. The fatigue analysis verifies the welding area shall be capable of withstanding under fatigue loading, identifies how critical area shall be selected and presents the principles to be used for design verification.

• Nuclear Engineering and Technology
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• v.54 no.3
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• pp.917-925
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• 2022

Steam generator (SG) tubes in a nuclear power plant can undergo rapid changes in pressure and temperature during an accident; thus, an accurate model to predict short-term creep damage is essential. The theta (𝜃) projection method has been widely used for modeling creep-strain behavior under constant stress. However, many creep test data are obtained under constant load, so creep rupture behavior under a constant load cannot be accurately simulated due to the different stress conditions. This paper proposes a novel methodology to obtain the creep curve under constant stress using a modified 𝜃 projection method that considers the increase in true stress during creep deformation in a constant-load creep test. The methodology is validated using finite element analysis, and the limitations of the methodology are also discussed. The paper also proposes a creep-strain model for alloy 690 as an SG material and a novel creep hardening rule we call the damage-fraction hardening rule. The creep hardening rule is applied to evaluate the creep rupture behavior of SG tubes. The results of this study show its great potential to evaluate the rupture behavior of an SG tube governed by creep deformation.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.5
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• pp.67-76
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• 2003

The principal operation rule of irrigation reservoir is to accelerate the water use and supply water actively when water is sufficient, and to restrict water use and supply water deficiently in order not to stop the irrigation activity when water is scarce. In drought seasons. water should be saved in order to keep the reservoir not to be dried up during the irrigation season. It is important to know how much water should be saved, depending on the rice-growing season and water storage volume. For the drought control of irrigation reservoirs. the rotational irrigation scheduling in paddy with the operation rule curve developed in this study could be utilized as a software program to install TM/TC system for irrigation water supply by automation facilities.

• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.E
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• pp.47-54
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• 1995

Irrigation water has been mainly used for paddy rice. Irrigated paddy land tends to be recently converted to land for green house, farm house, and rural-industrial complex. Consequently, demand of water for crops, domestic & industrial, rural recreations, small-scaled hydropower, livestocks, and environment in the rural area, so called rural water, is rapidly increasing. In order to supply rural water, water in the existing irrigation reservoir could be enlarged by repairment of irrigation canal and reinforcement of irrigation reservoir, and be saved by the operation rule curve, utilization of dead water, and balanced storage management.