• Geotechnical Engineering
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• v.11 no.3
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• pp.113-122
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• 1995

The purposes of this study are to investigate the mechanical prospeities of the inter mediate soils through consolidation tests and triaxial compression shear tests. The intermediate soils used in this study are artificial soils which are composed of sea clay, sand and it's crushed component. The relationship between plastic index and mechanical prosperties (permeability and compressibility) is investigated through series of consoli dation tests. Strain hardening phenomenon under shearing is explored based on several overconsideration ratios and strain rates in undrained shear tests. To make a comparative study difference of drain condition and strain rate, drain shear tests are performed with overconsolidation ratio.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.2
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• pp.7-12
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• 2008

In this study, the wide width effect that the increasing rate of drain current and the value of cutoff frequency decrease with larger finger number is observed. For modeling this effect, an improved SPICE MOSFET RF model that finger number-independent external source resistance is connected to a conventional BSIM3v3 RF model is developed. Better agreement between simulated and measured drain current and cutoff frequency at different finger number is obtained for the improved model than the conventional one, verifying the accuracy of the improved model for $0.13{\mu}m$ multi-finger MOSFET.

• STI Policy Review
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• v.5 no.2
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• pp.43-64
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• 2014

Korea has pursued an aggressive policy of inviting more foreign-born students to its universities since the late 1990s in the wake of the globalization of education markets and its changing demographic structure. While increasingly more students from Asia come to Korea for study, more than half of the graduates return home upon graduation. Given the issues of brain drain, brain circulation, and knowledge transfer that are raised by such a high return rate, this paper examines the factors that frame the foreign students' decision on their post-graduation careers. By analyzing survey data, we report that Asian students majoring in science, technology, engineering, and mathematics (STEM) are more likely to return than non-STEM majors. This suggests that Korea's aggressive policies of inviting foreign-born students have contributed to brain circulation and knowledge transfer between Korea and the other Asian countries. We also find that scholarships from Korean sources and positive attitudes toward Korean culture and life increase their inclination to stay in the country upon graduation. These findings, however, raise more questions than answers, since it becomes obvious that their post-graduation decisions are highly affected by what Korea as a society provides.

• Annals of Hepato-Biliary-Pancreatic Surgery
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• v.27 no.1
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• pp.63-69
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• 2023

Methods: Patients who underwent cholecystectomy were classified into two groups according to their GBWT status (GBWT+ vs. GBWT-). Results: Among 1,211 patients who underwent cholecystectomy, GBWT+ was seen in 177 (14.6%). The GBWT+ group was significantly older with more males, higher ASA score, higher alkaline phosphatase level, higher international normalized ratio, and lower albumin level than the GBWT- group. On ultrasound, GBWT+ patients had larger stone size, more pericholecystic fluid, more common bile duct stone, and more biliary pancreatitis. Compared with the GBWT- group, the GBWT+ group had more urgent surgeries (12.4% vs. 3.2%, p = 0.001), higher conversion rate (4.5% vs. 0.3%, p = 0.001), prolonged operative time (67 ± 38 vs. 54 ± 29 min; p = 0.001), more bleeding (3.4% vs. 0.5%, p = 0.002), and more need of drain (21.5% vs. 10.5%, p = 0.001). By multivariate analysis, factors associated with increased length of hospital stay were GBWT+ (HR: 1.97, 95% CI: 1.19-3.25, p = 0.008), urgent surgery (HR: 10.2, 95% CI: 4.07-25.92, p = 0.001), prolonged surgery (HR: 1.01, 95% CI: 1.0-1.02, p = 0.001), and postoperative drain (HR: 11.3, 95% CI: 6.40-20.0, p = 0.001). Conclusions: Variables such as GBWT ≥ 5 mm, urgent prolonged operation, and postoperative drains are independent predictors of extended hospital stay. GBWT+ patients are twice likely to stay in hospital for more than 72 hours and more prone to develop complications than GBWT- patients.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.5
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• pp.973-980
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• 2005

In this paper, we analyze previous flow control algorithm for serving ABR traffic, and then propose the algorithm which calculate fair transmission rate and control efficiently ABR traffic using VS/VD switch which has an effect on PNNI environment with long delay. For getting the transmission rate, the proposed algorithm use FMMRA as ER scheme which calculate exactly the fair share. And, in large delay state, we can obtain fair cell sharing by calculating transmission rates which obtained by transmitted queue length information of VD to VS for serve and drain cell in queue Through the computer simulation, we evaluate the performance of proposed algorithm. According to the results, the proposed algorithm shows good performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9A
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• pp.1413-1421
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• 2000

In this paper, we analyze previous flow control algorithm for serving ABR traffic, and then propose the algorithm which calculate fair transmission rate and control efficiently ABR traffic using VS/VD switch which has an effect on WAN environment with long delay. For getting the transmission rate, the proposed algorithm use FMMAR as ER scheme which calculate exactly the fair share. And, in large delay state. we can obtain fair cell sharing by calculating transmission rates which obtained by transmitted queue length information of VD to VS for serve and drain cell in queue Through the computer simulation, we evaluate the performance of proposed algorithm. According to the results, the proposed algorithm shows good performance.

• Journal of the Korean Geotechnical Society
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• v.15 no.6
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• pp.111-120
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• 1999

Leachate flow behavior due to intermediate cover soil of low hydraulic conductivity and the applicability of pumping method for reducing the leachate level in the landfill are analyzed with the numerical flow model, MODFLOW. Using the hydraulic conductivity and storativity data obtained from the field pumping and slug tests(Jang and Cho, 1999), the hydraulic condition within the landfill is validated. The optimum rate of pumping, the radius of influence, and the efficiency of horizontal drain are analyzed for reducing the leachate level in the landfill. From the results of the analyses, the barrier effect that the buried cover soil of low hydraulic conductivity prevents the vertical movement of leachate flow through the cover soil, which is found from the in-situ geotechnical studies(Jang and Cho, 1999), is identified again. Also, the installation of horizontal drains to the pumping well can increase the pumping rate from 120 ton/day per a well to 300 ton/day. The length of horizontal drain did not influence significantly on the drawdown-time curve of leachate in the landfill.

• Journal of Soil and Groundwater Environment
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• v.9 no.2
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• pp.1-10
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• 2004

The purpose of this study is to evaluate a laboratory test on arsenic reduction efficiency for ARD (Acid Rock Drainage) using limestone and apatite, and to design an apatite drain system. As a result of the laboratory test, results of this study show that pH, arsenic removal ratio, and dissolution amount of limestone ＆ apatite are inversely proportional to flow rates, and apatite removes 100％ of arsenic at 0.6 ml/min/kg flow rate. It is supposed that dissolution rate of apatite is ten times higher than that of limestone. The arsenic compounds are assumed to be Johnbaumnite, and/or Ca-arsenic hydrate. According to the results of the laboratory test, apatite drain system is designed as follow; Sixty two tons of apatite will be needed per one year and six months, and the precipitates will be removed from the precipitation pond per 3 months.

• Journal of the Korean Geosynthetics Society
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• v.15 no.1
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• pp.47-57
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• 2016

Many researchers reported that artesian pressure exists in thick soft ground of Busan Nakdong river estuary. Artesian pressure in soft ground could affect rate of consolidation, settlement and drainage capasity of prefabricated vertical drain(PVD). This paper investigated consolidation behaviors of soft ground with partially penetrated PVD subjected to artesian pressure. Laboratory tests with 1-dimensional large column equipment and their numerical analyses were carried out. Test results showed that the consolidation settlement of clay ground with artesian pressure was higher than that without artesian pressure. Due to artesian pressure, the dissipation rate of excess pore water pressure was reduced in soft ground with artesian pressure, especially at bottom part of clay ground. Numerical results were in good agreement with experimental test results.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.8
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• pp.54-61
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• 2001

A fully on-chip open-drain CMOS output driver was designed for high bandwidth DRAMs, such that its output voltage swing was insensitive to the variations of temperature and supply voltage. An auto refresh signal was used to update the contents of the current control register, which determined the transistors to be turned-on among the six binary-weighted transistors of an output driver. Because the auto refresh signal is available in DRAM chips, the output driver of this work does not require any external signals to update the current control register. During the time interval while the update is in progress, a negative feedback loop is formed to maintain the low level output voltage ($V_OL$) to be equal to the reference voltage ($V_{OL.ref}$) which is generated by a low-voltage bandgap reference circuit. Test results showed the successful operation at the data rate up to 1Gb/s. The worst-case variations of $V_{OL.ref}$ and $V_OL$ of the proposed output driver were measured to be 2.5% and 7.5% respectively within a temperature range of $20^{\circ}C$ to $90^{\circ}C$ and a supply voltage range of 2.25V to 2.75V, while the worst-case variation of $V_OL$ of the conventional output driver was measured to be 24% at the same temperature and supply voltage ranges.