• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.2
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• pp.371-378
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• 2020

Rainfall is one of the most active forces that cause soil erosion. The action of rain on the soil exerts an erosive power caused by the impact of the drops, which fall with variable speed and kinetic energy, depending directly on the diameter of the drop. The objective of this study is to determine algorithms capable of estimating rainfall erosivity for the region of Maceió-AL. For this purpose, erosion rains were collected between 2003 and 2006 using a RD-69 disdrometer, which continuously and automatically measures rainfall distribution in a range of 1 min. The determination of algorithms in the form of power equation to estimate was adjusted with one and two independent variables (amount of rainfall, duration and maximum intensity).

• Journal of Ecology and Environment
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• v.41 no.2
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• pp.34-44
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• 2017

Background: Monitoring terrestrial vegetation cover condition is important to evaluate its current condition and to identify potential vulnerabilities. Due to simplicity and low cost, point intercept method has been widely used in evaluating grassland surface and quantifying cover conditions. Field-based digital photography method is gaining popularity for the purpose of cover estimate, as it can reduce field time and enable additional analysis in the future. However, the caveats and uncertainty among field-based vegetation cover estimation methods is not well known, especially across a wide range of cover conditions. We compared cover estimates from point intercept and digital photography methods with varying sampling intensities (25, 49, and 100 points within an image), across 61 transects in typical steppe, forest steppe, and desert steppe in central Mongolia. We classified three photosynthetic groups of cover important to grassland ecosystem functioning: photosynthetic vegetation, non-photosynthetic vegetation, and bare soil. We also acquired normalized difference vegetation index from satellite image comparison with the field-based cover. Results: Photosynthetic vegetation estimates by point intercept method were correlated with normalized difference vegetation index, with improvement when non-photosynthetic vegetation was combined. For digital photography method, photosynthetic and non-photosynthetic vegetation estimates showed no correlation with normalized difference vegetation index, but combining of both showed moderate and significant correlation, which slightly increased with greater sampling intensity. Conclusions: Results imply that varying greenness is playing an important role in classification accuracy confusion. We suggest adopting measures to reduce observer bias and better distinguishing greenness levels in combination with multispectral indices to improve estimates on dry matter.

• Journal of Oral Medicine and Pain
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• v.45 no.2
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• pp.23-28
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• 2020

Purpose: Temporomadibular disorders (TMDs) can result in chronic pain, which is often associated with psychological and sleep disturbance. Increased levels of psychological and sleep impairments are often related with poor treatment outcomes. The purpose of the present study was to evaluate clinical features, psychological profiles and the prevalence of clinical insomnia in TMD patients with chronic pain and to suggest an effective treatment approach. Methods: A total of 200 TMD patients who had visited the Pusan National University Hospital dental clinic for treatment of their pain were recruited from June 2018 through December 2019. TMD patients were classified into an acute (n=100) and chronic (n=100) group and compared the clinical symptoms. The primary diagnosis of TMD were categorized as TMD with joint pain group (TMD_J), TMD with muscle pain group (TMD_M) and TMD with joint-muscle mixed pain group (TMD_JM). Self- report measures of sleep quality and psychological profiles were evaluated via the Insomnia Severity Index (ISI) and the Korean Stress Response Inventory (SRI). Independent t-tests, Mann-Whitney U-tests, and chisquared test were used for the statistical analysis. Results: Chronic TMD patients showed higher pain intensity, as well as higher prevalence of related symptoms (headache, musculoskeletal pain) and myogenous pain. They also had significantly higher scores in all SRI parameters and a higher percentage of clinical insomnia than acute TMD patients. Conclusions: Based on the above results, psychological profiles and sleep quality assessments are necessary to provide essential data that will allow for improved treatment of chronic TMD patients.

• Earthquakes and Structures
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• v.14 no.6
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• pp.577-587
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• 2018

The quantitative assessment of the seismic collapse risk of a structure requires the usage of an optimal intensity measure (IM) which can adequately characterise the severity of the ground motion. Research suggests that the average spectral acceleration ($Sa_{avg}$) may be an efficient and sufficient alternate IM as compared to the more traditional first mode spectral acceleration, $Sa(T_1)$, particularly during seismic collapse risk estimation. This study primarily presents a comparative evaluation of the sufficiency of the average spectral acceleration with respect to ground motion duration, and secondarily assesses the impact of ground motion duration on collapse risk estimation. By assembling a suite of 100 historical ground motions, incremental dynamic analysis of 60 different inelastic single-degree-of-freedom (SDF) oscillators with varying periods and ductility capacities were analysed, and collapse risk estimates obtained. Linear regression models are used to comparatively quantify the sufficiency of $Sa_{avg}$ and $Sa(T_1)$ using four significant duration metrics. Results suggests that an improved sufficiency may exist for $Sa_{avg}$ when the period of the SDF system increases, particularly beyond 0.5, as compare to $Sa(T_1)$. In reference to the ground motion duration measures, results indicated that the sufficiency of $Sa_{avg}$ is more sensitive to significant duration definitions that consider almost the full wave train of an accelerogram ($SD_{a5-95}$ and $SD_{v5-95}$). In order to obtain a reduced variability of the collapse risk estimate, the 5-95% significant duration metric defined using the Arias integral ($SD_{a5-95}$) should be used for seismic collapse risk estimation in conjunction with $Sa_{avg}$.

• Geomechanics and Engineering
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• v.21 no.2
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• pp.179-186
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• 2020

Investigating damage potential of the railway infrastructure requires either large amount of case histories or in-depth numerical analyses, or both for which large amounts of effort and time are necessary to accomplish thoroughly. Rather than performing comprehensive studies for each damage case, in this study we collect and analyze a case history of the high-speed railway system damaged by the 2004 M6.6 Niigata Chuetsu earthquake for the development of the seismic fragility curve. The development processes are: 1) slice the railway system as 200 m segments and assigned damage levels and intensity measures (IMs) to each segment; 2) calculate probability of damage for a given IM; 3) estimate fragility curves using the maximum likelihood estimation regression method. Among IMs considered for fragility curves, spectral acceleration at 3 second period has the most prediction power for the probability of damage occurrence. Also, viaduct-type structure provides less scattered probability data points resulting in the best-fitted fragility curve, but for the tunnel-type structure data are poorly scattered for which fragility curve fitted is not meaningful. For validation purpose fragility curves developed are applied to the 2016 M7.0 Kumamoto earthquake case history by which another high-speed railway system was damaged. The number of actual damaged segments by the 2016 event is 25, and the number of equivalent damaged segments predicted using fragility curve is 22.21. Both numbers are very similar indicating that the developed fragility curve fits well to the Kumamoto region. Comparing with railway fragility curves from HAZUS, we found that HAZUS fragility curves are more conservative.

• Journal of Digital Convergence
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• v.15 no.2
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• pp.519-525
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• 2017

The purpose of this study is to elaborate the factors and strategies to revitalize the policies of elderly-friendly care industry. The analysis was carried out using the method called DEMATEL. The analytical method is based on the DEMATEL technique. The purpose of this study is to clarify the complexity and unclear relationship between activation factors and factors that constitute the elderly friendly-care industry through the prioritization of policy strengthening. As the result of analysis, it was analyzed that the most intensive activation intensity was the highest total strength of meal service(22.095). Followed by health promotion facilities(19.97) and health care(17.726). The lowest factor is sport(15.896). Therefore, in order to improve and promote these factors, continuous policy measures should be sought that are closely related to facility care services, home care services, and preventive support services.

• Phonetics and Speech Sciences
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• v.2 no.2
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• pp.101-108
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• 2010

An inhaled salbutamol and salmeterol for chronic obstructive pulmonary disease(COPD) and asthma have been used worldwidely. But there has been few study about the voice change evoked from the post-medicine effect. To evaluate the voice influenced of short-acting and long-acting ${\beta}_2$-agonists, two experiments were carried out: one was salbutamol experiment 1 with eight patients, the other was salmeterol experiment 2 with six patients. Experiment 1 was made of two stages: premedication & postmedication. Experiment 2 was four stages: stageI was premedication, stageII was postmedication & pregaggling, stageIII was postmedication & postgaggling(100 ml with water), and stageIV was postmedication & 30 minutes later. Measured parameters were F0, F0_SD, Jitter_rap, Shimmer_apq11, HNR, BW(1, 2, 3), Intensity, and H1-H2. The mean data collected from 3 repetitions each was statistically analyzed by Wilcoxon signed rank test for experiment 1 and repeated measures ANOVA for experiment 2. In experiment 1, significant differences were found in the Jitter_rap(Z= -2.10, p=0.036). The findings indicated that the postmedicated voice was worse than premedicated voice. In experiment 2, there wasn't significant difference, but values of parameters related to voice quality(Jitter_rap, Shimmer_apq11, HNR, and H1-H2) showed changes toward stageⅣ, that is, the voice quality was worse under medication.

• The Journal of the Acoustical Society of Korea
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• v.34 no.4
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• pp.321-327
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• 2015

In this paper, we propose an algorithm for achieving robust Visual Voice Activity Detection (VVAD) for enhanced speech recognition. In conventional VVAD algorithms, the motion of lip region is found by applying an optical flow or Chaos inspired measures for detecting visual speech frames. The optical flow-based VVAD is difficult to be adopted to driving scenarios due to its computational complexity. While invariant to illumination changes, Chaos theory based VVAD method is sensitive to motion translations caused by driver's head movements. The proposed Local Variance Histogram (LVH) is robust to the pixel intensity changes from both illumination change and translation change. Hence, for improved performance in environmental changes, we adopt the novel threshold estimation using total variance change. In the experimental results, the proposed VVAD algorithm achieves robustness in various driving situations.

• Safety and Health at Work
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• v.1 no.2
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• pp.149-157
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• 2010

Objectives: To quantify disability level in salespeople with concurrent low back pain (LBP) and to determine the relative associations between demographic, occupational, psychosocial and clinical factors and back disability. LBP is the most common cause of work-related disability in people under 45 years of age and the most expensive cause of work-related disability, in terms of workers' compensation and medical expenses. Evidence suggests high prevalence of LBP in salespeople. Methods: A cross-sectional survey was conducted in which 184 saleswomen with a current episode of self-reported LBP working in a large up-scale department store filled out a battery of 6 self-administered questionnaires and received a standardised physical examination. Results: Saleswomen with concurrent LBP had low disability levels. Factors significantly associated with disability were pain intensity, measured by a visual analogue scale, in the past week (p < 0.001), physical and mental health status (p < 0.001, p = 0.003, respectively), fear avoidance scores for both work and physical activities (p = 0.031, p = 0.014, respectively), past history of LBP (p = 0.019), and self-reported frequency of pushing or pulling objects placed in high positions during work (p = 0.047). A significant level (45%) of the variance in disability status was explained by these variables. Conclusion: In clinical management of LBP workers who required prolonged standing, such as salespeople, clinicians should look for modifiable risk factors associated with disability. Specific measures need to be taken to prevent disability due to LBP among salespeople.

• Journal of electromagnetic engineering and science
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• v.18 no.2
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• pp.78-87
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• 2018

This paper describes specular reflectance measurements of dielectric plates in three waveguide frequency bands: D-band (110-170 GHz), G-band (140-220 GHz), and J-band (220-325 GHz). The transmit (Tx) part of the proposed specular reflectance measurement system is stationary, while the receive (Rx) part and the material under test (MUT) holder are concentric-rotating with a 2:1 speed ratio for specular reflectance measurements. In specular reflectance measurements, the first step measures the specular reflection coefficients of an MUT and a metal plate on the MUT holder located at the center of the Tx and Rx parts, and the second step calculates the specular reflectance defined by the specular reflection power (i.e., intensity) of the MUT normalized to that of the metal plate. Multiple reflection effects between the Tx and Rx antennas and the MUT on the measured specular reflectance are minimized by averaging out the multiple specular reflectances measured with changing the separation distance between the two antennas by ${\lambda}/8$ intervals. Measurement results of the perpendicular-polarized specular reflectance of commonly used dielectric plates are verified by comparing those with the analytic results and show that the results measured over the overlapped frequency range of the D-/G-bands and at the boundary frequency of the G-/J-bands agree well with the results for the other band, respectively.