• Atmosphere
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• v.29 no.5
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• pp.525-535
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• 2019

Vertical distributions of aerosol mass concentrations over Seoul and Gangneung from January to February 2015 were investigated using aerosol Mie-scattering lidars. Vertical mass concentration of aerosol was calculated from the lidar data using KALION's algorithm and quantitatively compared with ground PM₁₀ concentration to obtain objectivity of data. The backward trajectories calculated using HYSPLIT (version 4) were clustered into 5 traces for Seoul and 6 traces for Gangneung, and the observed aerosol vertical mass distribution was analyzed for individual trajectories. Result from the analysis shows that, aerosol concentrations with in the planetary boundary layer were highest when airflows into the measurement points originated in the Shandong Peninsula or the Inner Mongolia. In addition, the difference of aerosol mass concentrations in the two regions below 1 km was about twice as large as that in the long range transport from the Shandong Peninsula compared to the local emission. This result shows that the air quality over Korea related to particulate matters are affected more by aerosol emissions in the upstream source regions and the associated transboundary transports than local emissions. This study also suggests that the use of local aerosol observations is critical for accurate simulations of aerosol-cloud interactions.

• Journal of KIISE:Software and Applications
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• v.28 no.12
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• pp.947-954
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• 2001

In this paper, we propose a method for the recognition of various head gestures with automata technique applied to the sequence of facial pose states. Facial regions as detected by using the optimum facial color of I-component in YIQ model and the difference of images adaptively selected. And eye regions are extracted by using Sobel operator, projection, and the geometric location of eyes Hierarchical feature analysis is used to classify facial states, and automata technique is applied to the sequence of facial pose states to recognize 13 gestures: Gaze Upward, Downward, Left ward, Rightward, Forward, Backward Left Wink Right Wink Left Double Wink, Left Double Wink , Right Double Wink Yes, and No As an experimental result with total 1,488 frames acquired from 8 persons, it shows 99.3% extraction rate for facial regions, 95.3% extraction rate for eye regions 94.1% recognition rate for facial states and finally 99.3% recognition rate for head gestures. .

• Proceedings of the Fisheries Business Administration Society of Korea Conference
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• 2007.12a
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• pp.167-184
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• 2007

The objectives of this paper are to identify the causes of the corporate distress and to develop a distress prediction model with the financial information in fishery industry. In this study, the corporate distress is defined as economic failure and technical insolvency. Economic failure occurs by reduction, shut-down, or change of the business and technical insolvency results from failure to pay the financial debt of companies. The 33 distressed firms from 1991 to 2003 were composed by 14 economic failure companies, 15 technical insolvency companies. 4 companies applied to the both cases. The analysis of distress prediction of fishery companies were accomplished according to the distress definition. The analysis was carried out as two steps. The first step was the univariate analysis, which was used for checking the prediction power of individual financial variable. The t-test is used to identify the differences in financial variables between the distressed group and the non-distressed group. The second step was to develop distress prediction model with logistic regression. The variables showed the significant difference in univariate analysis were selected as the prediction variables. The financial ratios, used in the logistic regression model, were selected by backward elimination method. To test stability of the distress prediction model, the whole sample was divided as three sub-samples, period 1(1990$\sim$1993), period 2(1994$\sim$1997), period 3(1998$\sim$2002). The final model built from whole sample appled each three sub-samples. The results of the logistic analysis were as follows. the growth, profitability, stability ratios showed the significant effect on the distress. the some different result was found in the sub-sample (economic failure and technical insolvency). The growth and the profitability were important to predict the economic failure. The profitability and the activity were important to predict technical insolvency. It means that profitability is the really important factor to the fishery companies.

• The Journal of Fisheries Business Administration
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• v.39 no.2
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• pp.61-79
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• 2008

The objectives of this paper are to identify the causes of the corporate distress and to develop a distress prediction model with the financial information in fishery industry. In this study, the corporate distress is defined as economic failure and technical insolvency. Economic failure occurs by reduction, shut - down, or change of the business and technical insolvency results from failure to pay the financial debt of companies. The 33 distressed firms from 1991 to 2003 were composed by 14 economic failure companies, 15 technical insolvency companies. 4 companies applied to the both cases. The analysis of distress prediction of fishery companies were accomplished according to the distress definition. The analysis was carried out as two steps. The first step was the univariate analysis, which was used for checking the prediction power of individual financial variable. The t - test is used to identify the differences in financial variables between the distressed group and the non - distressed group. The second step was to develop distress prediction model with logistic regression. The variables showed the significant difference in univariate analysis were selected as the prediction variables. The financial ratios, used in the logistic regression model, were selected by backward elimination method. To test stability of the distress prediction model, the whole sample was divided as three sub-samples, period 1(1990 - 1993), period 2(1994 - 1997), period 3(1998 - 2002). The final model built from whole sample appled each three sub - samples. The results of the logistic analysis were as follows. the growth, profitability, stability ratios showed the significant effect on the distress. the some different result was found in the sub - sample (economic failure and technical insolvency). The growth and the profitability were important to predict the economic failure. The profitability and the activity were important to predict technical insolvency. It means that profitability is the really important factor to the fishery companies.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.7
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• pp.169-179
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• 2014

In this paper, we propose a DOF (Depth of Field) correction technique by determining the values of the internal parameters of a 3-D camera which consists of stereoscopic cameras of different optical properties. If there is any difference in the size or the depth range of focused objects in the left and right stereoscopic images, it could cause visual fatigue to human viewers. The object size of in the stereoscopic image is corrected by the LUT of zoom lenses, and the forward and backward DOF are corrected by the object distance. Then the F-numbers are determined to adjust the optical properties of the camera for DOF correction. By applying the proposed technique to a main-sub type 3-D camera using a GUI-based DOF simulator, the DOF of the camera is automatically corrected.

• The KIPS Transactions:PartC
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• v.16C no.3
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• pp.347-356
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• 2009

In an RFID search protocol, a reader uses designated query to determine whether a specific tag is in the vicinity of the reader. This fundamental difference makes search protocol more vulnerable to replay attacks than authentication protocols. Due to this, techniques used in existing RFID authentication protocols may not be suitable for RFID search protocols. In this paper, we propose two RFID search protocols, one based on static ID and the other based on dynamic ID, which use counter to prevent replay attacks. Moreover, we propose a security model for RFID search protocols that includes forward/backward traceability, de-synchronization and forgery attack. Based on this model, we analyze security of our protocols and related works.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.2
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• pp.49-57
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• 2019

Purpose: This study aimed to investigate the application of temperature to balance the training by observing the effect of sensory changes in the foot sole area on dynamic equilibrium ability through change in the sole temperature. Methods: Participants (n=49), who were selected as a certain standard, applied cold and hot packs for ten minutes at two-week intervals, and the laboratory's internal temperature was maintained at $25^{\circ}C$. The subjects were measured before and after the cold and hot applications in the stable condition with bare feet. Before each experiment applied the cold and hot packs, the balance ability of the ordinary temperature was measured once by conducting a limit of stability test using Biorescue, and the changes in balance ability were observed by measuring once after applying the temperature to the foot sole by means of the ice pack and the hot pack. Results: The results of the dynamic balance test, both before and after the temperature application, were compared, and it was confirmed that the moving area before and after cold application decreased significantly, and the moving area before and after application was not significantly different. The mean of pre-post area differences was found to have decreased at a statistically significant rate in the forward, backward, rightward, leftward, and total areas for the group that received the cold application compared to the group that received the hot application. Conclusion: These findings showed that cold application to the foot sole decreased dynamic balance. There was no significant difference in the dynamic balance ability both before and after the hot application to the foot sole, so it is difficult to conclude that the hot application affected dynamic balance.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.2
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• pp.60-67
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• 2019

To understand the low frequency instability(LFI) characteristics in hybrid rockets combustion, effects of equivalence ratio variations on the phase shift between pressure and heat release oscillations were investigated by using the direct numerical simulation. The change in the equivalence ratio of the main chamber was simulated by the temperature and composition variation of the combustion gas introduced into the post-combustion chamber. In the results, additional combustion appeared along with vortex generation at the backward step, and combustion pressure and heat release oscillations were observed as the vortex moved. In addition, the results confirmed that the phase difference between the pressure and heat release oscillation shifts because of the changes in the propagation velocity of pressure wave as the temperature of combustion gas changes.

• PNF and Movement
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• v.17 no.1
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• pp.93-101
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• 2019

Purpose: This study aimed to investigate lower extremity muscle activation to the variable weight shift on the affected side of patients with hemiplegia. Methods: Eighteen patients with chronic hemiplegia volunteered to participate in this study. All participants performed three types of weight shift (sideways, forward, and backward) in limits of stability on the affected side. Muscle activation in a paralyzed leg was measured with electromyography on the gluteus medius, tensor fasciae latae, rectus femoris, and biceps femoris; furthermore, the attached area was recommended by SENIAM projects. Each weight shift was performed three times, and then the mean value of the three measurements was analyzed. The data were analyzed by measuring the symmetrically standing position with the reference voluntary contraction (RVC) and was standardized with the percentage of RVC method. Results: No significant difference in lower extremity muscle activation occurred according to the three types of variable weight shift. However, significant differences in lower extremity muscle activation did occur with each weight shift position. In addition, activation increased at the rectus femoris and decreased at the gluteus medius and tensor fasciae latae. Conclusion: Hip abductor muscle strength training and variable weight shifts on the affected side must increase to improve patients'balance and limits of stability.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.329-329
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• 2022

Accurate characterization of terrestrial precipitation variation from high spatial resolution satellite sensors is beneficial for urban hydrology and microscale agriculture modeling, as well as natural disasters (e.g., urban flooding) early warning. However, the widely-used top-down approach for precipitation retrieval from microwave satellites is limited in several hydrological and agricultural applications due to their coarse spatial resolution. In this research, we aim to apply a novel bottom-up method, the parameterized SM2RAIN, where precipitation can be estimated from soil moisture signals based on an inversion of water balance model, to generate high spatial resolution terrestrial precipitation estimates at 0.01º grid (roughly 1-km) from the C-band SAR Sentinel-1. This product was then tested against a common reanalysis-based precipitation data and a domestic rain gauge network from the Korean Meteorological Administration (KMA) over central South Korea, since a clear difference between climatic types (coasts and mainlands) and land covers (croplands and mixed forests) was reported in this area. The results showed that seasonal precipitation variability strongly affected the SM2RAIN performances, and the product derived from separated parameters (rainy and non-rainy seasons) outperformed that estimated considering the entire year. In addition, the product retrieved over the mainland mixed forest region showed slightly superior performance compared to that over the coastal cropland region, suggesting that the 6-day time resolution of S1 data is suitable for capturing the stable precipitation pattern in mainland mixed forests rather than the highly variable precipitation pattern in coastal croplands. Future studies suggest comparing this product to the traditional top-down products, as well as evaluating their integration for enhancing high spatial resolution precipitation over entire South Korea.