• The Journal of Engineering Geology
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• v.23 no.2
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• pp.105-115
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• 2013

Increasing the river cross-section by barrage construction causes rises in the average river water levels and discharge rates in the rainy season. The time series patterns for groundwater levels measured at 23 riverside monitoring wells along the lower Nakdong River are compared for two cases: before and after water-filling at the Changnyeong-Haman Barrage. Monthly average groundwater levels indicate a distinct increase in groundwater levels in the upstream riverside close to the barrage. River-water level management by barrage gate control in August, during the rainy season, resulted in a 0.1 m decrease in groundwater levels, while water-filling at the barrage in December caused a 1.3 m increase in groundwater levels. The results of hierarchical cluster analysis indicate that seven groundwater monitoring wells and river water levels were in the same group before barrage construction, but that this number increased to 14 after barrage construction. Principal component analysis revealed that the explanation power of two principal components corresponding to river fluctuation, PC1 and PC2, was approximately 82% before barrage construction but decreased to 45% after construction. This finding indicates that the effect of the river level component that contributes to change in groundwater level, decreases after barrage construction; consequently, other factors, including groundwater pumping, become more important. Continuous surveying and monitoring is essential for understanding change in the hydrological environment. Water policy that takes groundwater-surface water interaction into consideration should be established for riverside areas.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1611-1615
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• 2006

The purpose of this study is to simulate the riverbed profile changes downstream of Daecheong re-regulation dam from 1988 to 2001, to evaluate the model's applicability and to predict a long-term riverbed-level variation between 2002 and 2017. As a result of simulation 14 sediment transport equations provided by GSTAR-1D, it was found that Acker's & White formula was the most stable relatively. The interval used to calculate its stability was 7 days for bankful discharge$(1,000m^2/s)$, 3 days for daily maximum flow$(4,273m^2/s)$, 1 day for hourly maximum flow$(7,605m^2/s)$ and minimum flow$(8.5m^2/s)$. The simulation results of river bed changes were evaluated and compared to its measure data from 1988 to 2001. It was showed that there was the degradation for a section between Daecheong re-regulation dam and Maepo water stage gage station due to bed-material, and the degradation for a reach between Maepo and Gongju water stage gage station due to massive aggregate collection. Also, as a result of simulating the river profile change for 2002 to 2017, it was predicted that the section between Daecheong re-regulation dam and Geumnam Bridge would remain as the present profile and the reach between Maepo and Gongju water stage gage station would have some degradations in several parts, which would be stable as a whole unless it was due to artificial river profile change.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.55
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• pp.209-240
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• 2012

Since the age of Lord Mansfield, who laid the foundation of the modern English insurance contract law in the second part of the 18th century, English insurance law has developed a unique rule of warranty. Lord Mansfield adopted very different approach and afforded such a strict legal character to insurance warranty, because the promise, given by the insured, played an important role for the insurer to assess the scope of the risk insured at that time. It is still important that the insured keep his promises strictly to the insurer under the insurance contract, but legal environments have changed dramatically since the times of Lord Mansfield. English Law Commission proposed some proposals for reforming the warranty regime to reflect the changes of legal environment in CP 2007. This article is, therefore, designed to examine the proposals and consider their legal and practical implications. The proposals of Law Commission is summarized as following. First, in CP 2007, Law Commission made two principal proposals for reform of the law on warranty. The first is that the insurer should not be entitled to rely on a breach of warranty unless the insured has been provided with a witten statement of what they have undertaken under warranty. The second is that the insurer should not be entitled to reject a claim on the ground that the insured has breached a warranty unless there was a causal connection between the breach and the loss. Secondly, for consumer insurance, the rule requiring a causal connection would be mandatory, whereas for business insurance, it would be possible for the parties to agree on the effect a breach of warranty should have, provided they use clear language to express their intentions. Thirdly, where the insured contracted on the insurer's written standard terms of business, some statutory controls would be afforded to the contract to ensure that the cover was not substantially different from what the insured reasonably expected. Finally, Law Commission propose that a breach of warranty give the insurer the right to terminate the contract, rather than automatically discharging it from liability, but (unless otherwise agreed) only if the breach has sufficiently serious consequences to justify termination under the general law of contract. Having evaluated the proposals of the Law Commission and considered their legal and practical implications, it is quite clear that the proposed rule interfere with freedom of contract and create legal uncertainty. But change can not made without any victims, so Law Commission's attempt to change severe and injust aspects of the warranty regime would be very welcomed and respected.

• The Journal of Engineering Geology
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• v.20 no.4
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• pp.449-459
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• 2010

We performed numerical simulations of the excavation of an underground structure (the Giheung Tunnel) in order to evaluate the rate of groundwater flow into the structure and to estimate the groundwater level around the structure. The tunnel was constructed in Precambrian bedrock in Gyeonggi Province, South Korea. Geological and electrical resistivity data, as well as hydraulic test data, were used for the numerical modeling. The modeling took into account the strike-slip faults that cross the southern part of Giheung Tunnel, as these structures influence the discharge of groundwater into the tunnel. The transient modeling estimated a groundwater flow rate into the tunnel of $306\;m^3$/day, with a grout efficiency of 40%, yielding good agreement between the calculated change in groundwater level (6.20 m) and that observed (6.30 m) due to tunnel excavation.

• Journal of Gastric Cancer
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• v.4 no.4
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• pp.225-229
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• 2004

Purpose: Some patients develop gastroesophageal reflux disease (GERD) after a gastrectomy for stomach cancer. Therefore, we conducted this research to gain an understanding of esophageal acidity and motility change. Materials and Methods: From July 2002 to March 2004, the cases of 15 randomized patients with stomach cancer who underwent a radical subtotal gastrectomy (RSG) with Billroth I(B-I) reconstruction (n=12) or a radical total gastrectomy (RTG) with Roux-en-Y (R-Y) gastroenterostomy (n=3) were analyzed. We investigated the clinical values of the ambulatory 24-hour pH monitoring and esophageal manometry in these patients, just before discharge from the hospital after an operation. Results: GERD was present in three patients ($20\%$). Compared with two reconstructive procedures, 3 of the 12 patients in the RSG with B-I group had GERD; however, none of RTG with R-Y group had GERD. Compared with pathologic stage, 2 of 9 patients in stage I, 1 of 2 patients in stage II, none of 3 patients in stage III, and none of 1 patient in stage IV had GERD. Esophageal manometry was performed in 10 patients. Nonspecific esophageal motility disorder (NEMD) was present in 7 patients. Conclusion: Some patients had GERD as a complication following a gastrectomy for stomach cancer. We suspect that the postoperative esophageal symptom is due to not only bile reflux but also gastroesophageal acid reflux. Therefore, careful observation is recommended for the detection of GERD.

• Journal of the Korean Geographical Society
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• v.29 no.3
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• pp.253-265
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• 1994

The hydraulic-geometrica1 relations between the riverbed slope and water discharge and other hydraulic variables in some selected alluvial rivels in Korea have been investigated. The rivers from which the data relevant to this study were collected are mainly the first tributaries, considered to be mostly in the equilibrium state, of the 10 major rivers in Korea. The investigating methods adopted in this study are similar to the one suggested by Leopold and Maddock and the one suggested by Garde. All of 18 rivers their drainage areas of which range between 100-2,000 $\textrm{km}^2$ were considered and the changes in riverbed slope, drainage area, bed material size along the downstream river distance were measured. It is found in this study that the change in the riverbed slope, S, along the downstream can be expressed in terms of the coefficient, $\beta$, expressing the change in the drainage area along the downstream and the drainage area, A, by an empirical relation as 0.0063 0.0063 S = $S_{ 0}$ $A_{0}$$^{-------- +0.51}$A-$^{-------- -0.51}$. $\beta$ $\beta$ According to this relation, the riverbed slope of the river reaches investigated in this study appear to be proportional to the -0.6th power of the drainage area. This result is consistent with the previous ones obtained by Hack.k.

• Journal of Korea Water Resources Association
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• v.42 no.7
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• pp.537-546
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• 2009

Determination of optimal pressure monitoring location is essential to manage water distribution system efficiently and safely. In this study, entropy theory is applied to overcome defects of previous researches about determining the optimal sensor location. The previous studies required the calibration using historical data, therefore, it was difficult to apply the proposed method in the place where the enough data were not available. Also, most researches have focused on the locations to minimize cost and maximize accuracy of the model, which is not appropriate for the purpose of maintenance of the water distribution system. The proposed method in this study quantify the entropy which is defined as the amount of information calculated from the pressure change due to the variation of discharge. When abnormal condition is occurred in a node, the effect on the entire network is presented by the entropy, and the emitter is used to reproduce actual pressure change pattern in EPANET. The optimal location to install pressure sensors in water distribution system is the nodes having the maximum information from other nodes. The looped and branched networks are evaluated using the proposed model. As a result, entropy theory provides general guideline to select the locations to install pressure sensors and the results can be used to help decision makers.

• Journal of Korea Water Resources Association
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• v.47 no.12
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• pp.1121-1134
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• 2014

The distributed watershed model of rainfall-runoff-soil erosion-sedimen transport was constructed for the Naesung Stream Watershed with high potentiality and risk of sediments produced by soil erosion. The sensitivity analyses of roughness coefficient and hydraulic conductivity which affected the modeling results of runoff and sediment concentration were performed in this study. As a result, the change of the roughness coefficient for the forest area from 0.4 to 0.45 did not affect the change in runoff and stream discharge and the average value and range of sediment concentration were also insignificantly increased with few difference. As a result of the sensitivity analysis of the hydraulic conductivity, the total amount of runoff and maximum runoff were gradually increased as the hydraulic conductivity was reduced. In the case of sediment concentration modeling, the average and the range of sediment concentration for all stations were increased as the hydraulic conductivity was decreased. For the Hyangseok Station, in case of the hydraulic conductivity reduced by 50%, the simulation result of sediment concentration was most similar to the estimated value by the sediment rating curve.