• Journal of the Korean Geotechnical Society
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• v.22 no.9
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• pp.61-68
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• 2006

Recently the large scale civil engineering projects are being implemented by reclaiming the sea or utilizing seashore and river embankment areas. The reclaimed land and utilized seashore are mostly soft ground that doesn't have sufficient bearing capacity. This soft ground consists of fine-grained soil such as clayey and silty soils or large void soil like peat or loose sand. It has high ground water table and it may cause the failure and crock of building foundation by uplift pressure and ground water leakage. In this study, the permittivity and the transmissivity were evaluated with the applied normal pressure in the laboratory. The laboratory model tests were conducted by utilizing geocomposite drainage system for draining the water out to release the uplift pressure. The soil used in the laboratory drainage test was dredged soil from the reclaimed land where uplift pressure problems can arise in soil condition. Geocomposite drainage system was installed at the bottom of apparatus and dredged soil was layered with compaction. Subsequently the water pressure was supplied from the top of specimen and the quantities of drainage and the pore water pressure were measured at each step water pressure. The results of laboratory measurements were compared with theoretical values. For the evaluation of propriety of laboratory drainage test, 2-D finite elements analysis that can analyze the distribution and the transferring of pore water pressure was conducted and compared with laboratory test results.

• Childhood Kidney Diseases
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• v.2 no.2
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• pp.95-103
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• 1998

Purpose : To find and solve the common problems of peritoneal dialysis(PD) by analysing the clinical data of pediatric PD performed in Korea. Methods : 264 cases of CAPD and acute PD had been performed from Nov.1987 to Oct. 1997 in 17 institutions of pediatric nephrology in Korea. Results : CAPD was performed in 114 cases. The mean age of the patients was $10.5{\pm}6.6$ years and male to female ratio was 1.4:1. The original renal diseases of ESRD were proven in 92 cases($80\%$). The common renal disease of ESRD were FSGS($17\%$), reflux nephropathy ($11\%$), chronic glomerulonephritis($9.6\%$). Mean duration of CAPD was $20{\pm}16.9$ months. Peritonitis was the most common complication and incidence was one episode/18.2 patient-months. Other complications were exit site infection in 10 cases, obstruction in 7 cases, leakage of dialysate in 6 cases. The most common etiologic organism of peritonitis was staphylococcus aureus and the next was staphylococcus coagulase(-). Acute PD was performed in 150 cases. Most common underlying causes were congenital heart disease, hemolytic uremic syndrome, sepsis and dehydration. The mean duration was $10.3{\pm}11.3$ days. The most common complication was peritonitis($20.6\%$). The most common etiologic organism was staphylococcus aureus and coagulase(-), acinetobactor and pseudomonas. Conclusion : Reflux nephropathy should be emphasized in early diagnosis and treatment to prevent ESRD. Incidence of congenital anomaly($7\%$) as a original disease of ESRD was relatively low in Korea. Growth status was not significantly improved after CAPD. In acute PD, the incidence of peritonitis was rapidly increased at 2weeks after beginning of dialysis.

• Information Systems Review
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• v.15 no.2
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• pp.1-19
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• 2013

Smart working sparked by iPhone3 opens a revolution in smart ways of working at any time, regardless of location and environment. Also, It provide real-time information processing and analysis, rapid decision-making and the productivity of businesses, including through the timely response and the opportunity to increase the efficiency. As a result, every company are developing mobile information systems. But company data is accessed from the outside, it has problems to solve like security, hacking and information leakage. Also, Mobile devices such as smart phones belonging to the privately-owned asset can't be always controlled to archive company security policy. In the meantime, public smart phones owned by company was always applied security policy. But it can't not apply to privately-owned smart phones. Thus, this paper is focused to archive company security policy, but also enable the individual's free to use of smart phones when we use mobile information systems. So, when we use smart phone as individual purpose, the normal operation of all smart phone functions. But, when we use smart phone as company purpose like mobile information systems, the smart phone functions are blocked like screen capture, Wi-Fi, camera to protect company data. In this study, we suggest the design and implementation of real time control and management of mobile device using MDM(Mobile Device Management) solution. As a result, we can archive company security policy and individual using of smart phone and it is the optimal solution in the BYOD(Bring Your Own Device) era.

• Tuberculosis and Respiratory Diseases
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• v.52 no.2
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• pp.156-165
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• 2002

Background: A tracheal stenosis is caused by mucosal ischemic injury related to a high cuff pressure ($P_{cuff}$) of the endotracheal tube. In contrast, aspiration of the upper airway secretion and impaired gas exchange due to cuff leakage is related to a low $P_{cuff}$. To prevent these complications, the $P_{cuff}$ should be kept appropriately because the appropriate $P_{cuff}$ appears to change according to the patient's daily respiratory mechanics. However, the constant cuff volume($V_{cuff}$) has frequently been instilled to the cuff balloon on a daily basis to maintain the optimal $P_{cuff}$ instead of monitoring the $P_{cuff}$ directly at the patients' bedside. To address the necessity of continuous $P_{cuff}$ monitoring, the change in the $P_{cuff}$ was evaluated at various $V_{cuff}$ levels on a daily basis in patients with long-term mechanical ventilation. The utility of mercury column sphygmomanometer for the continuous monitoring $P_{cuff}$ was also investigated. Method: The change in $P_{cuff}$ according to the increase in $V_{cuff}$ was observed in 17 patients with prolonged endotracheal intubation for mechanical ventilation for 2 week or more. This maneuver measured the change in $P_{cuff}$ daily during the mechanical ventilation days. In addition, the $P_{cuff}$ measured by mercury column sphygmomanometer was compared with the $P_{cuff}$ measured by an automatic cuff pressure manager. Results : There were no statistically significant changes of $P_{cuff}$ during more than 14 days of intubation for mechanical ventilation. However the $V_{cuff}$ required to maintain the appropriate $P_{cuff}$ varied from 1.9 cc to 9.6 cc. In addition, the intra-individual variation of the $P_{cuff}$ was observed from 10 $cmH_2O$ to 46 $cmH_2O$ at constant 3 cc $V_{cuff}$. The $P_{cuff}$ measured by the bedside mercury column sphygmomanometer is well coincident with that measured by the automatic cuff pressure manager. Conclusion: Continuous monitoring and management of the $P_{cuff}$ to maintain the appropriate $P_{cuff}$ level in order to prevent cuff related problems during long-term mechanical ventilation is recommended. For this purpose, mercury column sphygmomanometer may replace the specific cuff pressure monitoring equipment.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.2
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• pp.183-193
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• 2018

Currently, the Korea Atomic Energy Research Institute (KAERI) is planning to build the Ki-Jang Research Reactor (KJRR) in Ki-Jang, Busan. It is important to safely dispose of low-level radioactive waste from the operation of the reactor. The most efficient way to treat radioactive waste is cement solidification. For a radioactive waste disposal facility, cement solidification is performed based on specific waste acceptance criteria such as compressive strength, free-standing water, immersion and leaching tests. Above all, the leaching test is important to final disposal. The leakage of radioactive waste such as $^{137}Cs$ causes not only regional problems but also serious global ones. The cement solidification method is simple, and cheaper than other solidification methods, but has a lower leaching resistance. Thus, this study was focused on the development of cement solidification for an enhancement of cesium leaching resistance. We used Zeolite and Loess to improve the cesium leaching resistance of KJRR cement solidification containing simulated KJRR liquid waste. Based on an SEM-EDS spectrum analysis, we confirmed that Zeolite and Loess successfully isolated KJRR cement solidification. A leaching test was carried out according to the ANS 16.1 test method. The ANS 16.1 test is performed to analyze cesium ion concentration in leachate of KJRR cement for 90 days. Thus, a leaching test was carried out using simulated KJRR liquid waste containing $3000mg{\cdot}L^{-1}$ of cesium for 90 days. KJRR cement solidification with Zeolite and Loess led to cesium leaching resistance values that were 27.90% and 21.08% higher than the control values. In addition, in several tests such as free-standing water, compressive strength, immersion, and leaching tests, all KJRR cement solidification met the waste acceptance or satisfied the waste acceptance criteria for final disposal.

• Journal of Chest Surgery
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• v.32 no.9
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• pp.799-805
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• 1999

Background: Leakage, stricture formation, and tumor recurrence at the anastomotic site are serious problems after esophagectomy for cancer of the esophagus or cardia. The prevalence of these postoperative complications may be affected by whether an anastomosis is made in the neck or in the chest, therefore a comparison was made between anastomoses made at these two sites. Material and Method: Between 1987 and 1998, 36 patients with cancer of the esophagus underwent transthoracic esophagectomy with cervical(NA, n=20) or thoracic anastomosis(CA, n=16). The tumors were staged postoperatively(stage IIA, n=13; s tage IIB, n=7; stage III, n=16) and were located in the middle thoracic(n=22) or lower thoracic esophagus and cardia(n=14). Result: The overall operative mortality was 8.3%(5% for NA group, 12.5% for CA group). The anastomotic leak rate for the NA group was 15.0% and 12.5% for the CA group. The anastomotic leak rate differed according to the manual(27.3%) or stapled(8.0%) techniques(p < 0.05). The median proximal resection margins in the NA and CA groups were 9.6 cm and 5.8 cm, and the corresponding rates of anastomotic tumor recurrence were 5.3% and 28.6%(p < 0.05). The prevalence of benign stricture formation (defined as moderate/severe dysphagia) was higher in the NA group(36.8%) than in the CA group(21.4%). When an anastomosis was made by the stapled technique, smaller size of the staple increased the prevalence of stricture formation - 41.7% with 25-mm staple and 9.1% with 28-mm staple(p < 0.05). Conclusion: Wider resection margin could decrease the anastomotic tumor recurrence, and the stapled technique could decrease the anastomotic leak. The prevalence of benign stricture was higher in the cervical anastomosis but the anastomotic leak and smaller size(25-mm) of the staple should be considered as risk factors.

• Journal of Soil and Groundwater Environment
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• v.14 no.4
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• pp.33-44
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• 2009

Water curtain of an underground LPG storage cavern is a facility to prevent leakage of high pressure gases, for which groundwater should flow freely towards the cavern and groundwater level also must be stably maintained. In this study, in order to evaluate qualities of seepage water and surrounding groundwater of an underground LPG storage cavern in Yeosu, 4 rounds of samplings, field measurements and laboratory analyses (February, May, August, October of 2007) were conducted. According to field measurements, pH was weak acidic to neutral but it gradually increased with time. Electrical conductivity (EC) of groundwater near a salt stack showed very high values between 10.47 and 38.50 mS/cm. Dissolved oxygen (DO) showed a very wide range of 0.20~8.74 mg/L and a mean of oxidation-reduction potential (ORP) was 159 mV, which indicated an oxidized condition. Levels of $Fe^{2+}$ and $Mn^{2+}$ were mostly less than 3 mg/L. All of seepage waters showed a Na-Cl type while only groundwater near the salt stack showed a Na-Cl type with a high total dissolved solid. The other groundwaters exhibited typical $Ca-HCO_3$ types. Levels of aerobic bacteria were mostly very high (573-39,520 CFU/mL). Based on the analyses of these hydrochemistry and biological characteristics, it is concluded that there are no particular problems in groundwater and seepage water, which not causing a trouble in the cavern operation. However, both for control of bio-clogging and for sustainable operation of the water curtain system, a regular hydrochemical and microbiological monitoring is required for the seepage water and surrounding groundwater.

• Journal of Korean Society of Disaster and Security
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• v.12 no.1
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• pp.11-21
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• 2019

This study assessed the risk of disaster by using QRE(Quick Risk Estimation - UNISDR Roll Model City of Basic Evaluation Tool) tools for three natural disasters and sixteen social disasters managed by the Seoul Metropolitan Government. The criteria for selecting 19 disaster types in Seoul are limited to disasters that occur frequently in the past and cause a lot of damage to people and property if they occur. We also considered disasters that are likely to occur in the future. According to the results of the QRE tools for disaster type in Seoul, the most dangerous type of disaster among the Seoul city disasters was "suicide accident" and "deterioration of air quality". Suicide risk is high and it is not easy to take measures against the economic and psychological problems of suicide. This corresponds to the Risk ratings(Likelihood ranking score & Severity rating) "M6". In contrast, disaster types with low risk during the disaster managed by the city of Seoul were analyzed as flooding, water leakage, and water pollution accidents. In the case of floods, there is a high likelihood of disaster such as localized heavy rains and typhoons. However, the city of Seoul has established a comprehensive plan to reduce floods and water every five years. This aspect is considered to be appropriate for disaster prevention preparedness and relatively low disaster risk was analyzed. This corresponds to the disaster Risk ratings(Likelihood ranking score & Severity rating) "VL1". Finally, the QRE tool provides the city's leaders and disaster managers with a quick reference to the risk of a disaster so that decisions can be made faster. In addition, the risk assessment using the QRE tool has helped many aspects such as systematic evaluation of resilience against the city's safety risks, basic data on future investment plans, and disaster response.

• Journal of the Korean Geosynthetics Society
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• v.20 no.2
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• pp.23-33
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• 2021

In Korea, many reservoirs have been built for the purpose of solving the food shortage problem and supplying agricultural water. However, the current 75.6% of the reservoirs are in serious aged as more than 50 years have passed since the year of construction. In the case of such an aging reservoir, the stability due to scour and erosion inside the reservoir is very reduced, and if concentrated rainfall due to recent abnormal weather occurs, the aging reservoir may collapse, leading to a lot of damage to property and human life. Accordingly, each agency that manages aging reservoirs uses Ordinary Portland Cement (OPC) as an injection material and applies the grouting method. However, in the case of OPC, it may deteriorate over time and water leakage may occur again. And there are environmental problems such as consumption of natural resources and generation of greenhouse gases. So, there is a need to develop new materials and methods that can replace the OPC. In this study, an laboratory test and analysis were performed on the grout material developed to induce a curing reaction similar to that of OPC by recycling power plant byproduct. In addition, test in the field such as electric resistivity survey, Standard Penetration Test (SPT), and field permeability test were performed to analyzed to reinforcement effect and determine the possibility of using instead of OPC. As a results of the test, in the case of recycled power plant byproduct, the compressive strength was 2.9 to 3.2 times and the deformation modulus was 2.3 to 3.3 times higher, indicating that it is excellent in strength and can be used instead of OPC. And it was analyzed that the N value of the reservoir was increased by 1~2, and the coefficient of permeability (k) decreased to the level of 8.9~42.5%. showing sufficient reinforcing effect in terms of order.