• JSTS:Journal of Semiconductor Technology and Science
• /
• v.17 no.3
• /
• pp.401-410
• /
• 2017

In this work, we show that the excessive lattice heating problem due to parasitic pnp transistor action in the diode electrostatic discharge (ESD) protection device in the diode input protection circuit, which is favorably used in CMOS RF ICs, can be solved by adopting a symmetrical cathode structure. To explain how the recipe works, we construct an equivalent circuit for input human-body model (HBM) test environment of a CMOS chip equipped with the diode protection circuit, and execute mixed-mode transient simulations utilizing a 2-dimensional device simulator. We attempt an in-depth comparison study by varying device structures to suggest valuable design guidelines in designing the protection diodes connected to the $V_{DD}$ and $V_{SS}$ buses. Even though this work is based on mixed-mode simulations utilizing device and circuit simulators, the analysis given in this work clearly explain the mechanism involved, which cannot be done by measurements.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2012.05a
• /
• pp.40-47
• /
• 2012

Hydrologic responses to the 4September 2010 $M_W$ 7.1 and 22 February 2011 $M_W$ 6.2 Canterbury earthquakes ranged from near instantaneous co-seismic liquefaction and changes in groundwater levels, to more sustained (days to months) changes in river discharge, spring flow and groundwater level. There was some indication of a sustained change in aquifer properties. This paper presents some of the hydrographs from the September and February events, and compares the response to each event, briefly taking into account the location of the bore relative to each earthquake, together with other factors such as borehole depth. Over the months following the September earthquake, a pattern emerged of relatively short-term responses in the shallow aquifers and in the confined aquifer system, close to the coast. A longer term response appears to have occurred in inland, deep bores, where water levels 12 months after the September event were (in some cases) up to 20 metres higher than would have been expected based on simple modelling (see Figure 3). Some examples of these are highlighted.

• Proceedings of the KIPE Conference
• /
• 2019.11a
• /
• pp.218-219
• /
• 2019

본 논문은 모드 유지 알고리즘이 적용된 직류 배전용 에너지 저장 장치(Energy Storage System, ESS)의 모듈형 운전 제어 기법에 관해 제안한다. 모드 유지 알고리즘은 설정된 방전 깊이(Depth of Discharge, DoD) 내에서 계통의 전력 수요 및 공급의 변화가 생긴 경우에 수시로 변화하는 충/방전 모드의 변경을 제한하는 알고리즘이다. 이를 통해 ESS의 가용 용량을 최대한 사용 가능하며, 계통의 전력 공급 및 부하 수요에 따라 계통의 동작 상태를 결정할 때 도움을 줄 수 있다. 제안한 알고리즘은 PSIM 시뮬레이션을 통해 검증하였다.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.39 no.2
• /
• pp.297-306
• /
• 2019

Since the centrifugal force acts on the flow in the curved channel, a transverse water surface gradient occurs and the thalweg is biased toward the outer bank. The submerged vanes may be used to solve various engineering problems of the curved channels. In order to analyze the influence of an attack angle and the distance between the vane arrays on the river bed variation and the superelevation in a bend, movable bed hydraulic experiments were conducted in a $90^{\circ}$ curved rectangular channel of a small-size gravel bed. Installing the submerged vanes in the bend increases the maximum scour depth. But if vanes are installed in a uniform obtuse angle, the scour depth may be reduced. If the flow rate in the channel bend with vanes equals to the channel forming discharge, the location of the maximum scour depth moved to the downstream and the superelevation increased. However if the flow rate is smaller than that, the location of the maximum scour depth moved upstream and the superelevation decreased. The channel bed change and the superelevation due to the installation of the submerged vanes have been dependent on the interaction of the attack angle, the flow rate, and the distance between the arrays.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2011.05a
• /
• pp.167-172
• /
• 2011

본 연구는 연직수문을 통과하는 흐름의 유량계수에 대한 연구이다. 개수로에서 널리 쓰이는 연직수문에서의 흐름 거동을 개방도와 상류수심 및 유량을 조절하여 이를 수리실험과 FLOW-3D에 적용시켜 이에 따른 결과를 비교 분석 하였다. 수리실험결과 자유흐름의 경우 개방도와 상류수심비에 따라 유량계수의 값이 0.5~0.6 사이에 분포함을 확인할 수 있었다. 수리실험과 FLOW-3D, 0.611법, Swamee 식의 유량계수 값들을 비교하였을 때 기존의 연구와 마찬가지로 Swamee의 식은 현저히 떨어지는 값을 보임을 확인할 수 있었다. 수치모의결과 수리실험과 비슷한 양상을 보이며 수문에서의 흐름을 잘 구현함을 확인할 수 있었다. 수로의 폭에는 큰 영향을 받지 않으며 개방된 수문의 개수에 대한 변화에 따라 약간의 차이가 있으나 대체적으로 유량계수의 값이 0.4~0.6에 분포됨을 확인할 수 있었다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2005.05b
• /
• pp.659-663
• /
• 2005

본 연구의 목적은 산악지역의 돌발홍수에 대비한 경보발령을 위한 한계유량을 산정하는 것이다. 돌발홍수는 강우-유출관계가 비선형적이어서 기존의 선형 강우-유출 해석이 곤란하므로 비선형적 접근 방법이 필요하다. 본 연구에서는 지형정보체계(GIS : Geographic Information System)를 이용하여 유역의 지형학적 특성인자와 GIUH 및 GCIUH의 매개변수를 산정함으로써, 유역특성자료의 불확실성을 감소시켰다. 이를 경보발령 체제가 기 설치 운영중인 단양군의 천동계곡에 적용하여 그 적합성을 판단하였다. 여기서, 경보발령을 위한 한계유량은 계곡의 수심이 위험수심(dangerous depth)이라고 판단한 0.5m이상이 될 때의 유량으로 정의하였고, 무강우가 30분간 지속되면 초기화 시키는 과정을 거쳤다. 그 결과 기존의 경보발령 체제와 비교하여 시간당 20mm의 강우량에 대해서는 경보를 발령하지 않으므로 기존에 잦은 경보발령에 의한 주민의 소음피해를 줄일수 있었으며, 시간당 100mm의 강우에 대해서는 2-3분 간격으로 경보를 발령하여 주민의 안전을 도모할수 있었다.

• The Journal of the Convergence on Culture Technology
• /
• v.9 no.3
• /
• pp.137-143
• /
• 2023

This study was conducted to analyze factors affecting the length of stay in children with injuries by determining relationships between length of stay and characteristics of children(aged 0 to 12) with injuries. 7,804 patients aged 0 to 12 who participated in the Korea Nation Hospital Discharge In-Depth Injury Surveys, got a diagnosis of sequelae of injuries and of other consequences of external causes(S00-T98), and were discharged between 1 January 2016 and 31 December 2020 were investigated. A frequency analysis, independent samples t-test, and ANOVA were performed. Also, to identify factors affecting the length of stay, a regression analysis was performed. The average length of stay for the patients investigated in this study was 5.5 days. The length of stay for school-age children(aged 7 to 12) and children who had either public or private coverage was higher than that for preschoolers(aged 0 to 6) and children who didn't have public or private coverage, respectively. The length of stay for children admitted to a hospital in a rural area(Jeolla-do or Gyeongsang-do) was higher than that for children admitted to a hospital in a metropolitan area and the length of stay for children admitted to a hospital that had 100-299 hospital beds was relatively long. However, children who first visited a hospital for outpatient care stayed relatively short in hospital and children who had been burned or injured in traffic crashes stayed relatively long in hospital. Children who got a secondary diagnosis and had a principal procedure or who died after being discharged were in hospital for a long time. The findings of this study shall be useful, as they identified characteristics related to the length of stay for Korean children with injuries and factors that determine the length of stay for those children by analyzing the national dataset, or more specifically, the data from the Korea National Hospital Discharge In-Depth Injury Surveys. The risk of child injuries can be easily reduced by taking actions to prevent them and providing safety education programs. The present study has provided essential baseline data for the provision of aggressive care for child injuries and the establishment of a range of policies for child injury prevention.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.5
• /
• pp.2293-2303
• /
• 2013

Objective: This study aims to determine whether national patient safety indicators (PSIs) can be calculated. Methods: Using PSI criteria from Organization for Economic Co-Operation and Development (OECD) Health Technical Papers 19 based on the Agency for Healthcare Research and Quality (AHRQ), PSIs were identified in the Korean National Hospital Discharge In-depth Injury Survey (KNHDIIS) database for 875,622 inpatient admissions between 2004 and 2008. Logistic regression was used to estimate factors of variations for PSIs. Results: From 2004 to 2008, 3,084 PSI events of 8 PSIs occurred for over 80 thousands discharges. Rates per 1,000 events for decubitus ulcer (PSI3, 4.88), foreign body left during procedure (PSI5, 0.05), postoperative sepsis (PSI13, 1.32), birth trauma-injury to neonate (PSI17, 7.92) and obstetric trauma-vaginal delivery (PSI18, 32.81) are all identified between ranges from maximum to minimum of OECD rates, respectively. However, rates per 1,000 events for selected infections due to medical care (PSI7, 0.22), postoperative pulmonary embolism or deep vein thrombosis (PSI12, 0.90) and accidental puncture or laceration (PSI15, 0.71) are below the minimum of OECD range. 7 PSIs except PSI 18 showed statistically significant relationship with number of secondary diagnoses. When adjusting patient characteristics, there are statistically significant different rates according to bed size or location of hospitals. Conclusion: This is the first empirical study to identify nationally number of adverse events and PSIs using administrative database. While many factors influencing these results such as quality of data, clinical data and so on are remain, the results indicate opportunities for estimate national statistics for patient safety. Furthermore outcome research such as mortality related to adverse events is needed based on results of this study.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.12 no.4
• /
• pp.2078-2083
• /
• 1970

The purpose of this study is to give the data neccesary for improving the planning of drainage structures, specially inverted siphons, in irrigation channels. With the samples of 15 drainage inlets, one drainage flume, 16 drainage inverted siphons and 6 drainage culverts in the 3 lines of irrigation channel under Chong-Won Irrigation Association, author abtained the following results. 1. It is presumed that design drainage discharge should be determined with some additional reserves, on the basis of the maximum rainfall intensity in local area and the size of drainage area on the topographical map, avoiding the way of eye measure. 2. Location of drainage inlet should be kept away from the place where topography can make lots of wash load, but when unavoidably allowing the inflow into irrigation channel, wash load outlet with even the purpose of drainage, or drainage flume in stead of drainage inlet should be taken account of. 3. It is presumed that drainage flume may be the structure which can perform its function from a structural point of view as far as topography permits. 4. Drainage inverted siphon should be avoided at any place as much as possible; a) In case that location of the siphon would be permitted only at paddy field, drainage area hauing the amount of discharge which requires more than 90cm in diameter could only be allowed. b) In this case, crest elevation of the tank of both inlet and outlet, at least, should not be lower than the surface level of paddy field. c) As far as topography and stratum permit, ratio of depth of outlet tank to head drop should be decreased as much as possible so that discharging efficiency of wash load could increase. d) In case of avoiding the setting of the siphon, irrigation aqueduct, irrigation inverted siphon, or drainage flume should be recommended in accordance with topography. 5. Discharging capability of wash load by drainage culvert appeared to depend hardly upon the diameter of the culvert, but greatly upon the location, specially near village, for there stones and dirts dumped may considerably be piled up. So, a counter plan for that is required.

• Ocean and Polar Research
• /
• v.36 no.2
• /
• pp.87-101
• /
• 2014

Recently, more attention has been paid to the geomorphological changes in the Nakdong River Estuary, because those changes are caused by artificial activities including weirs, reclamation and construction. In order to analyze quantitatively the recent geomorphological variability in the Nakdong River Estuary, we surveyed the depth and elevation of submarine topography near Jinwoodo and Sinjado from March 2007 to February 2012. A statistical method (based on Digital Shoreline Analysis System) and an Empirical Orthogonal Functions method were used to evaluate the morphological changes. According to the statistical variables (DCE, NDC, EPR, LRR), the highest amount and rate of accumulation were recorded around the Gadeokdo whereas the greatest amount of erosion appeared around the coast off the eastern part of Sinjado. In particular, a dynamic variation of morphology was clearly observed in the vicinity of the sub-tidal channel located between Jinwoodo and Sinjado, which seems to be attributable to channel migration. As a result of the EOF method, the first mode (48.7%) is most closely related to the pattern of morphological variability that might be associated with the westerly movement of sediment by longshore current. The spatial variability of the second mode (16.6%) was high in the shoreface of Sinjado, showing a 4-year periodicity of temporal variability. The strong correlation (coefficient 0.73) between the time coefficient and suspended sediment discharge from Nakdong River emphasizes the role of sediment discharge to deposition in this area. The spatial variability of the third mode (11.3%) was distributed mainly around the coast off the eastern part of Sinjado, which is related to the movement of the coastline of Sinjado. Based on the last 5 year's data, our results suggest that the study area is characterized on the whole by a depositional pattern, but the extent of sedimentation is different locally.