• Korean Journal of Remote Sensing
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• v.39 no.5_3
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• pp.909-919
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• 2023

Benthic marine invertebrates, the invertebrates living on the bottom of the ocean, are an essential component of the marine ecosystem, but excessive reproduction of invertebrate grazers or pirate creatures can cause damage to the coastal fishery ecosystem. In this study, we compared and evaluated You Only Look Once Version 7 (YOLOv7), the most widely used deep learning model for real-time object detection, and detection tansformer (DETR), a transformer-based model, using underwater images for benthic marine invertebratesin the coasts of South Korea. YOLOv7 showed a mean average precision at 0.5 (mAP@0.5) of 0.899, and DETR showed an mAP@0.5 of 0.862, which implies that YOLOv7 is more appropriate for object detection of various sizes. This is because YOLOv7 generates the bounding boxes at multiple scales that can help detect small objects. Both models had a processing speed of more than 30 frames persecond (FPS),so it is expected that real-time object detection from the images provided by divers and underwater drones will be possible. The proposed method can be used to prevent and restore damage to coastal fisheries ecosystems, such as rescuing invertebrate grazers and creating sea forests to prevent ocean desertification.

• Journal of the Korean Geographical Society
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• v.40 no.2 s.107
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• pp.221-241
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• 2005

Land Use and Land Cover Changes (LUCC) occur over a wide range of space and time scales, and involve complex natural, socio-economic, and institutional processes. Therefore, modelling and predicting LUCC demands an understanding of how various measured properties behave when considered at different scales. Understanding spatial and temporal variability of driving forces and constraints on LUCC is central to understanding the scaling issues. This paper aims to 1) assess the heterogeneity of land cover change processes over the landscape in northern Ghana, where intensification of agricultural activities has been the dominant land cover change process during the past 15 years, 2) characterise dominant land cover change mechanisms for various spatial scales, and 3) identify the optimal spatial scale for LUCC modelling in a savanna landscape. A multivariate statistical method was first applied to identify land cover change intensity (LCCI), using four time-sequenced NDVI images derived from LANDSAT scenes. Three proxy land use change predictors: distance from roads, distance from surface water bodies, and a terrain characterisation index, were regressed against the LCCI using a multi-scale hierarchical adaptive model to identify scale dependency and spatial heterogeneity of LUCC processes. High spatial associations between the LCCI and land use change predictors were mostly limited to moving windows smaller than 10$\times$10km. With increasing window size, LUCC processes within the window tend to be too diverse to establish clear trends, because changes in one part of the window are compensated elsewhere. This results in a reduced correlation between LCCI and land use change predictors at a coarser spatial extent. The spatial coverage of 5-l0km is incidentally equivalent to a village or community area in the study region. In order to reduce spatial variability of land use change processes for regional or national level LUCC modelling, we suggest that the village level is the optimal spatial investigation unit in this savanna landscape.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.05a
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• pp.32-33
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• 2003

Mechanism of a periodic oscillation of shock-induced combustion over a two- dimensional wedges and axi-symmetric cones were investigated through a series of numerical simulations at off-attaching condition of oblique detonation waves(ODW). A same computational domain over 40 degree half-angle was considered for two-dimensional and axi-symmetric shock-induced combustion phenomena. For two-dimensional shock-induced combustion, a 2H2+02+17N2 mixture was considered at Mach number was 5.85with initial temperature 292 K and initial pressureof 12 KPa. The Rankine-Hugoniot relation has solution of attached waves at this condition. For axi-symmetric shock-induced combustion, a H2+2O2+2Ar mixture was considered at Mach number was 5.0 with initial temperature 288 K and initial pressure of 200 mmHg. The flow conditions were based on the conditions of similar experiments and numerical studies.[1, 3]Numerical simulation was carried out with a compressible fluid dynamics code with a detailed hydrogen-oxygen combustion mechanism.[4, 5] A series of calculations were carried out by changing the fluid dynamic time scale. The length wedge is varied as a simplest way of changing the fluid dynamic time scale. Result reveals that there is a chemical kinetic limit of the detached overdriven detonation wave, in addition to the theoretical limit predicted by Rankine-Hugoniot theory with equilibrium chemistry. At the off-attaching condition of ODW the shock and reaction waves still attach at a wedge as a periodically oscillating oblique shock-induced combustion, if the Rankine-Hugoniot limit of detachment isbut the chemical kinetic limit is not.Mechanism of the periodic oscillation is considered as interactions between shock and reaction waves coupled with chemical kinetic effects. There were various regimes of the periodicmotion depending on the fluid dynamic time scales. The difference between the two-dimensional and axi-symmetric simulations were distinct because the flow path is parallel and uniform behind the oblique shock waves, but is not behind the conical shock waves. The shock-induced combustion behind the conical shockwaves showed much more violent and irregular characteristics.From the investigation of characteristic chemical time, condition of the periodic instability is identified as follows; at the detaching condition of Rankine-Hugoniot theory, (1) flow residence time is smaller than the chemical characteristic time, behind the detached shock wave with heat addition, (2) flow residence time should be greater than the chemical characteristic time, behind an oblique shock wave without heat addition.

• Journal of Korean Physical Therapy Science
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• v.15 no.1
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• pp.29-38
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• 2008

The purposes of this study were to examine whether balance training through stabilization exercise had influence on the improvement of stroke patients' ability in balancing, and to understand whether the effects had the differences to traditional balance training, if it had effects. Subjects were divided into two groups, a stabilization exercise group(n=28) and a conventional balance exercise group (n=28), and a balance exercise program was conducted twice a day, 30 min for 1 time, 10 times a week for 4 weeks. After the program, the stabilization exercise showed significant improvement of balance ability in Bug Balance Scales (BBS), Functional Reach Test (FRT), Timed Up and Go Test (TUG), comparing with the status of pre －training, as well as the conventional balance training (p<.05). Independent samples t－test was executed in order to verify the significancy in the effects between the two groups and the result showed significant improvement in their average value after training for BBS. However, there was no significant difference in TUG and FRT. As a result, it was examined that partially, there was significant difference only in BBS. According to the results as presented above, if stabilization exercise, which can apply diverse movements and postures, properly keeps pace with conventional balance exercise, stroke patients would obtain significant effects on the improvement of balance ability.

• Atmosphere
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• v.19 no.1
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• pp.79-91
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• 2009

Seoul National University General Circulation Model (SNUGCM) has been run for 100 years to obtain daily temperature and meridional velocity at the Northern lower stratosphere. The model results are compared with the NCEP/NCAR reanalysis data. The polar temperature and the eddy heat flux from the model show that the model-produced climatology has well-known cold bias and weaker planetary wave activities. The model climatology also has a lag in the seasonal evolution. The relationship between the model-produced polar temperature and the eddy heat flux is investigated with respect to the interannual and decadal time scales. The interannual variation of the polar temperature is related with both total and stationary eddy heat flux in January and March, which is in agreement with observation. The model, however, does not reproduce the relationship between the decadal variation of the polar temperature and transient eddy heat flux, which is revealed in the observed data.

• Korean Journal of Human Ecology
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• v.22 no.5
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• pp.407-417
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• 2013

The purpose of this study was to investigate and analyze how teachers' recognition of professionalism and the child's gender and term care affect child's social interaction behavior. Participants were three-year-old 61 children and their 20 teachers. Each child was observed by the time sampling method of 20 sec-observation followed by 10 sec-recording for a total of 14 minutes. The teachers completed the rating scales to measure the teachers' recognition of professionalism. The study results show that, children engaged more frequently in individual behavior than in interactions with peers or with teachers in day care centers. And those children had more interaction behavior with their teachers than with their peers. Correlation between teachers' recognition of professionalism and children's social interaction behavior were as following: the more the teachers recognized professionalism, the more the children showed positive interaction behavior toward their teachers. Also, the more the teachers recognized the professionalism related to the job satisfaction, the more the children showed positive interaction behavior toward their peers. Boys interacted more negatively with peers and teachers than girls did. Children who attended the day care center more than two years showed less individual behaviors than others.

• Journal of Korean Academy of Nursing
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• v.30 no.5
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• pp.1347-1356
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• 2000

The present study is a descriptive study to investigate nurses’perception of barriers to research utilization. A total of 274 participants in this study consisted of registered nurses working in a large, urban and academic medical center. A questionnaire packet containing the Barriers Scale, and a demographic profile was distributed to nurses and they were asked to return the packet to a return-box in the Nursing Office after completion. The greatest barrier was insufficient time on the job to implement new ideas. Next was ‘implications for practice are not made clear'. Also the item of the English language in research articles was considered to be the ninth barrier. The greatest mean score of each of the sub-scales was the communication factor. The were followed by the organization, research, and nurse factors. Compared with the means from other studies, the mean scores of the communication and research factors were higher in this study. Nurses who had not taken a class of research methods found the communication and research factors as a higher barrier than those who did. Also, nurses who did not participate in a conference last year perceived the research factor as higher than those who did. It is recommended that English and research classes should be strengthened in educational nursing programs. The researchers should also describe the section of implication for practice as more detail and clearer for the understanding of nurses; Lastly journals in a libraries or online journal systems should be easily accessible.

• Korean Journal of Ichthyology
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• v.13 no.3
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• pp.195-200
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• 2001

Psenes maculatus and P. cyanophrys of family Nomeidae were collected for the first time off the coast of Tongyeong, Kyongsangnam-do, Korea. Specimens were catched with drifting seaweed patches on June and July, 1998. Young Psenes maculatus has six black bands ('<' shape) on the body, and 'Ttimul-reung-dom' is proposed as the Korean name. Psenes cyanophrys differs from P. pellucidus in having a compressed oval body shape scales on the check, and 16 longitudinal lines on the body. 'Jul-mu-nui-mul-reung-dom' is proposed as the Korean name.

• Korean Journal of Ichthyology
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• v.11 no.1
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• pp.29-32
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• 1999

From the South Sea in 1995, two species, Chaunax abei and Bembrops curvatura, were collected for the first time in Korea. C. abei and B. curvatura were closely similar to C. fimbriatus and B. caudimacula in exomorphological characters, respectively. C. abei sharply differed from C. fimbriatus in having the round green spots, no fossa in front of dorsal fin and without tentacles around illicium groove. B. curvatura was well divided from B. caudimacula in having 15 anal fin rays, 41~50 lateral line scales, deep curved lateral line and black color on the first dorsal fin membrane. New Korean name "Jom-ssinbengi" was proposed for the Chaunax abei, and "Jool-gupun-noontungi", B. curvatura, respectively.

• Journal of Ginseng Research
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• v.39 no.3
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• pp.274-278
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• 2015

Background: Steaming of ginseng is known to change its chemical composition and biological activity. This study was carried out to investigate the effect of different steaming time-scales on chemical constituents and antiproliferative activity of Vietnamese ginseng (VG). Methods: VG was steamed at $105^{\circ}C$ for 2-20 h. Its saponin constituents and antiproliferative activity were studied. The similarity of chemical compositions between steamed samples at $105^{\circ}C$ and $120^{\circ}C$ were compared. Results: Most protopanaxadiol and protopanaxatriol ginsenosides lost the sugar moiety at the C-20 position with 10-14 h steaming at $105^{\circ}C$ and changed to their less polar analogues. However, ocotillol (OCT) ginsenosides were reasonably stable to steaming process. Antiproliferative activity against A549 lung cancer cells was increased on steaming and reached its plateau after 12 h steaming. Conclusion: Steaming VG at $105^{\circ}C$ showed a similar tendency of chemical degradation to the steaming VG at $120^{\circ}C$ except the slower rate of reaction. Its rate was about one-third of the steaming at $120^{\circ}C$.