scholarly journals Innovation Of Naval Architecture And Ocean Engineering Curriculum At Seoul National University

2020 ◽  
Author(s):  
Hang Choi
Keyword(s):  
Engineering Curriculum ◽  
Ocean Engineering ◽  
Naval Architecture ◽  
National University ◽  
Seoul National University

Indoor Navigation System using Asynchronous Pseudolites

2003 ◽  
Vol 56 (3) ◽  
pp. 443-455 ◽  
Author(s):  
Changdon Kee ◽  
Haeyoung Jun ◽  
Doohee Yun
Keyword(s):  
Navigation System ◽  
Dynamic Error ◽  
Field Application ◽  
Indoor Navigation ◽  
Experimental Results ◽  
Ocean Engineering ◽  
National University ◽  
Potential Applications ◽  
Indoor Navigation System ◽  
Seoul National University

The Global Positioning System (GPS) is now attracting worldwide attention as a navigation sensor. One of the advantages of GPS is that people can find their position using a GPS receiver wherever they are except in obstructed environments. Existing GPS receivers do not work in an obstructed environment despite there being many potential applications. This paper shows the possibility of navigation using GPS technologies indoors in a blocked environment. The paper describes the pseudolite-based indoor navigation system that was developed and implemented at Seoul National University (SNU). The system, which uses GPS technologies, has some different characteristics to normal outdoor GPS systems. The differences cause some practical problems, such as near/far, time-tag, multipath and unknown transmission position problems, which need to be solved to implement the indoor navigation system. The paper introduces various methods for solving such problems. The paper then shows the experimental results and the system accuracy. The satisfactory experimental results show that the RMS static error is 1 mm(1σ) horizontally and 2 mm(1σ) vertically and the RMS dynamic error is 5·6 mm(1σ) horizontally and 15 mm(1σ) vertically. The paper also shows the result of a field application test in the ocean engineering basin of the Korea Research Institute of Ships & Ocean Engineering (KRISO).

scholarly journals Predictors of cervical myelopathy and hydrocephalus in young children with achondroplasia

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Youngbo Shim ◽  
Jung Min Ko ◽  
Tae-Joon Cho ◽  
Seung‐Ki Kim ◽  
Ji Hoon Phi
Keyword(s):  
Magnetic Resonance Imaging ◽  
Young Children ◽  
Cervical Myelopathy ◽  
Treatment Method ◽  
Foramen Magnum ◽  
Resonance Imaging ◽  
Timely Manner ◽  
Frontal Horn ◽  
National University ◽  
Seoul National University

Abstract Background Cervical myelopathy and hydrocephalus occasionally occur in young children with achondroplasia. However, these conditions are not evaluated in a timely manner in many cases. The current study presents significant predictors for cervical myelopathy and hydrocephalus in young children with achondroplasia. Methods A retrospective analysis of 65 patients with achondroplasia who visited Seoul National University Children’s Hospital since 2012 was performed. The patients were divided into groups according to the presence of cervical myelopathy and hydrocephalus, and differences in foramen magnum parameters and ventricular parameters by magnetic resonance imaging between groups were analyzed. Predictors for cervical myelopathy and hydrocephalus were analyzed, and the cut-off points for significant ones were calculated. Results The group with cervical myelopathy showed foramen magnum parameters that indicated significantly lower cord thickness than in the group without cervical myelopathy, and the group with hydrocephalus showed significantly higher ventricular parameters and ‘Posterior indentation’ grade than the group without hydrocephalus. ‘Cord constriction ratio’ (OR 5199.90, p = 0.001) for cervical myelopathy and ‘Frontal horn width’ (OR 1.14, p = 0.001) and ‘Posterior indentation’ grade (grade 1: OR 9.25, p = 0.06; grade 2: OR 18.50, p = 0.01) for hydrocephalus were significant predictors. The cut-off points for cervical myelopathy were ‘Cord constriction ratio’ of 0.25 and ‘FM AP’ of 8 mm (AUC 0.821 and 0.862, respectively) and ‘Frontal horn width’ of 50 mm and ‘Posterior indentation’ grade of 0 (AUC 0.788 and 0.758, respectively) for hydrocephalus. Conclusion ‘Cord constriction ratio’ for cervical myelopathy and ‘Frontal horn width’ and ‘Posterior indentation’ grade for hydrocephalus were significant predictors and may be used as useful parameters for management. ‘Posterior indentation’ grade may also be used to determine the treatment method for hydrocephalus.

scholarly journals Components of Metabolic Syndrome in Korean Adults: A Hospital-Based Cohort at Seoul National University Bundang Hospital

2019 ◽  
Vol 28 (2) ◽  
pp. 118-128 ◽  
Author(s):  
Soo Lim ◽  
Se Hee Min ◽  
Ji Hyun Lee ◽  
Lee Kyung Kim ◽  
Dong-Hwa Lee ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Korean Adults ◽  
National University ◽  
Seoul National University

Climate related variations in atmospheric nitrous oxide concentration during the Mid- to Late Holocene

2021 ◽  
Author(s):  
Syed Azharuddin ◽  
Jinho Ahn ◽  
Yeongjun Ryu ◽  
Ed Brook
Keyword(s):  
Nitrous Oxide ◽  
Late Holocene ◽  
Ice Core ◽  
Progressive Increase ◽  
La Niña ◽  
La Nina ◽  
National University ◽  
Seoul National University ◽  
Sudden Decrease ◽  
Nitrous Oxide Concentration

<p>Nitrous oxide (N<sub>2</sub>O) is an important greenhouse gas with sources that respond to the biogeochemical processes on land and ocean. The major sources of atmospheric N<sub>2</sub>O are nitrification and denitrification occurring in terrestrial soils and the ocean. Here we present a new high-resolution atmospheric N<sub>2</sub>O record obtained from South Pole Ice (SPICE) core site covering the Mid- to Late Holocene (since ~5.5 ka). The N<sub>2</sub>O analysis was performed in a specialised wet extraction facility installed at Seoul National University that used small ice samples (<20 g) to yield a high precision (average standard deviation of ~1ppb) record. The new N<sub>2</sub>O data agree well with existing records on the millennial scale and reveal new details on the multi-centennial scale. Our results show a progressive increase in atmospheric N<sub>2</sub>O during 5.5 to 3.2 ka which correlates well with the increase of marine denitrification around the Arabian Sea (AS) and Peru-Chile Margin (PCM) as well as Indian monsoon precipitation around the same period. A local minimum in N<sub>2</sub>O is observed around 2.8 ka, possibly related to a sudden decrease in Western Tropical South (WTS) Pacific sea surface temperature and increased La-Nina like conditions which may have supressed denitrification along PCM. These conditions may have further influenced the monsoons and reduced denitrification in land soils. Our record also shows a local N<sub>2</sub>O maximum around 2.2 ka which may correspond to relaxed La-Nina like conditions around WTS Pacific. Subsequently, the N<sub>2</sub>O further dropped to attain a pronounced minimum around 1.4 ka. Similar N<sub>2</sub>O minima are also observed in Styx (Antarctica) and  NEEM (Greenland) ice core records, demonstrating the robustness of the signals.</p>

scholarly journals Screening for early detection of lung cancer: results from Seoul National University Hospital.

1991 ◽  
Vol 38 (2) ◽  
pp. 119-127
Author(s):  
Yong Chol Han ◽  
Chul Gyu Yoo ◽  
Young Whan Kim ◽  
Sung Koo Han ◽  
Young Soo Shim ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Early Detection ◽  
University Hospital ◽  
National University ◽  
Seoul National University
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