• Phonetics and Speech Sciences
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• v.16 no.1
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• pp.33-40
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• 2024

This study investigated acoustic features in spectral moment analysis, comparing accurate articulations with distortions of alveolar fricatives such as dentalization, palatalization, and lateralization. A retrospective analysis was conducted on speech samples from 61 children (mean age: 5.6±1.5 years, 19 females, 42 males) using the Assessment of Phonology & Articulation for Children (APAC) and Urimal-test of Articulation and Phonology I (U-TAP I). Spectral moment analysis was applied to 169 speech samples. The results revealed that the center of gravity of accurate articulations was higher than that of palatalization, while palatalization was lower than dentalization. The variance of dentalization was higher than that of both accurate articulations and palatalization. The skewness of dentalization was higher than that of accurate articulations, and the skewness of palatalization was higher than that of accurate articulations. The kurtosis of palatalization was higher than that of both accurate articulations and dentalization. No significant differences were observed for the position of fricatives (initial, medial) and tense type (plain, tense) across all variables of spectral moment analysis for each distortion type. This study confirmed distinct patterns in center of gravity, variance, skewness, and kurtosis depending on the type of alveolar fricative distortion. The objective values provided in this study will serve as foundational data for diagnosing alveolar fricative distortions in children with speech sound disorders.

• Korean Journal of Radiology
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• v.21 no.9
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• pp.1055-1064
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• 2020

Objective: To assess the incremental prognostic value of coronary computed tomography angiography (CCTA) in comparison to a clinical risk model (Framingham risk score, FRS) and coronary artery calcium score (CACS) for future cardiac events in ischemic stroke patients without chest pain. Materials and Methods: This retrospective study included 1418 patients with acute stroke who had no previous cardiac disease and underwent CCTA, including CACS. Stenosis degree and plaque types (high-risk, non-calcified, mixed, or calcified plaques) were assessed as CCTA variables. High-risk plaque was defined when at least two of the following characteristics were observed: low-density plaque, positive remodeling, spotty calcification, or napkin-ring sign. We compared the incremental prognostic value of CCTA for major adverse cardiovascular events (MACE) over CACS and FRS. Results: The prevalence of any plaque and obstructive coronary artery disease (CAD) (stenosis ≥ 50%) were 70.7% and 30.2%, respectively. During the median follow-up period of 48 months, 108 patients (7.6%) experienced MACE. Increasing FRS, CACS, and stenosis degree were positively associated with MACE (all p < 0.05). Patients with high-risk plaque type showed the highest incidence of MACE, followed by non-calcified, mixed, and calcified plaque, respectively (log-rank p < 0.001). Among the prediction models for MACE, adding stenosis degree to FRS showed better discrimination and risk reclassification compared to FRS or the FRS + CACS model (all p < 0.05). Furthermore, incorporating plaque type in the prediction model significantly improved reclassification (integrated discrimination improvement, 0.08; p = 0.023) and showed the highest discrimination index (C-statistics, 0.85). However, the addition of CACS on CCTA with FRS did not add to the prediction ability for MACE (p > 0.05). Conclusion: Assessment of stenosis degree and plaque type using CCTA provided additional prognostic value over CACS and FRS to risk stratify stroke patients without prior history of CAD better.

• Korean Journal of Radiology
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• v.21 no.6
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• pp.695-706
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• 2020

Objective: To investigate the technical and clinical efficacy of the percutaneous insertion of a biliary metallic stent, and to identify the factors associated with biliary stent dysfunction in patients with malignant duodenobiliary obstruction. Materials and Methods: The medical records of 70 patients (39 men and 31 women; mean age, 63 years; range, 38-90 years) who were treated for malignant duodenobiliary obstruction at our institution between April 2007 and December 2018, were retrospectively reviewed. Variables found significant by univariate log-rank analysis (p < 0.2) were considered as suitable candidates for a multiple Cox's proportional hazard model. Results: The biliary stents were successfully placed in all 70 study patients. Biliary stent insertion with subsequent duodenal stent insertion was performed in 33 patients and duodenal stent insertion with subsequent biliary stent insertion was performed in the other 37 study subjects. The median patient survival and stent patency time were 107 days (95% confidence interval [CI], 78-135 days) and 270 days (95% CI, 95-444 days), respectively. Biliary stent dysfunction was observed in 24 (34.3%) cases. Multiple Cox's proportional hazard analysis revealed that the location of the distal biliary stent was the only independent factor affecting biliary stent patency (hazard ratio, 3.771; 95% CI, 1.157-12.283). The median biliary stent patency was significantly longer in patients in whom the distal end of the biliary stent was beyond the distal end of the duodenal stent (median, 327 days; 95% CI, 249-450 days), rather than within the duodenal stent (median, 170 days; 95% CI, 115-225 days). Conclusion: The percutaneous insertion of the biliary metallic stent appears to be a technically feasible, safe, and effective method of treating malignant duodenobiliary obstruction. In addition, a biliary stent system with a distal end located beyond the distal end of the duodenal stent will contribute towards longer stent patency in these patients.

• The Journal of the Convergence on Culture Technology
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• v.10 no.3
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• pp.643-650
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• 2024

Currently, South Korea is grappling with a paradoxical situation characterized by simultaneous labor shortages and job shortages. Within this context, retirees are citing conflicts with supervisors/colleagues and dissatisfaction with organizational culture as the primary reasons for their departure, with these issues disproportionately affecting the MZ generation. In response, scholars have conducted preliminary studies to understand the relationships between organizational culture and other variables specifically concerning the MZ generation. However, most of these studies are based on a unified theory of the MZ generation, failing to satisfy the practical demands for distinguishing between Generations M and Z. Therefore, this research aims to explore the differences in variable relationships between these two groups within the hospitality industry. Surveys were conducted among 170 individuals from Generation M and 110 from Generation Z, and the data were analyzed using AMOS structural equation modeling. The analysis confirmed that both hierarchical culture and generational conflict significantly define relationships across all generations, with generational conflict adversely affecting organizational commitment. Additionally, while a relationship-oriented culture negatively impacts generational conflict for Generation M, no such effect was observed for Generation Z. This study successfully identifies the differential impacts between Generation M and Generation Z.

• Journal of Wetlands Research
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• v.26 no.2
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• pp.160-167
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• 2024

The amphibians serve as environmental indicator species warning of threats from pollution and development, and information regarding their body condition and surrounding habitat can be utilized as crucial indicators for assessing ecosystem health. The objective of this study was to investigate the differences in body condition and the climate environments according to the season and sex of Class II endangered Kaloula borealis. A total of 53 surveys were conducted from June to October 2018, targeting frogs inhabiting the Godeok-dong area of Gangdong-gu, Seoul. Using the weight and length of each individual, the body condition index (SMI, Scaled mass index) was calculated. Results showed a total capture of 396 individuals, consisting of 235 males and 161 females. Females exhibited longer SVL and greater weight compared to males, with higher body condition indices. Monthly body condition indices were lower for males in June, while no differences were observed between males and females from July to September. Among the climate environments where females and males appeared, environmental variables related to precipitation and humidity showed differences. These research findings are deemed crucial for providing fundamental information to ascertain suitable habitats for Kaloula borealis and selecting alternative habitats due to developmental impacts in the future.

• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.4
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• pp.327-344
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• 2024

In general tunnel design and analysis, rock masses are often assumed to be isotropic. Under isotropic conditions, material properties are uniform in all directions, leading to a higher evaluation of tunnel stability. However, actual rock masses exhibit anisotropic characteristics due to discontinuities such as joints, bedding planes, and faults, which cause material properties to vary with direction. This anisotropy significantly affects the stress distribution during tunnel excavation, leading to non-uniform deformation and increased risk of damage. Therefore, thorough pre-analysis is essential. This study analyzes the displacement and stress changes occurring during tunnel excavation based on rock anisotropy. A three-dimensional numerical analysis was performed, selecting anisotropy index and dip angles as variables. The results showed that as the anisotropy index increased, the displacement in the tunnel increased, and stress concentration became more pronounced. The maximum displacement and shear stress were observed where the dip planes met the tunnel.

• The Journal of the Convergence on Culture Technology
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• v.10 no.4
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• pp.563-574
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• 2024

While the integration of chatbot and the simplification of financial terminology in Financial services' apps are increasingly common, automotive finance apps often show lower user satisfaction for complex terminol- ogy and rigid content. This study investigates the effects of chatbot interaction modes and the simplification of financial terminology on user experience in automotive finance apps. We developed prototypes for car lease tasks under different conditions: the type of user interaction channel (chatbot vs menu-based), and the usage of financial terminology. A 2 x 2 experimental survey was conducted to measure perceptions of friendliness, read- ability, trust, and accuracy. The findings revealed that chatbot interactions significantly enhance friendliness more than menu-based interactions, and simplifying terminology significantly improves readability and friendliness. However, no significant differences were observed in trust and accuracy between the conditions. Furthermore, nosignificant interaction effects were found between the two conditions across all variables. This study contributes by quantitatively assessing the impacts of chatbot consultation modes and terminology sim- plification on customer experience in financial services.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.3
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• pp.95-104
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• 2007

This study was focused on the effect of concrete strength and lateral ties of concrete columns subjected to eccentric compressive loads. The twenty-four concrete columns with $200mm{\times}200mm$ square cross-section were tested. The main variables were concrete strength, spacing and configuration of lateral ties, and eccentricity ratios. From the experiment, the followings were investigated ; 1) In all cases, it was observed that the increase of concrete compressive strength led to the decrease of ductility. Also, as the eccentricity ratios increased, the effect of ductility enhancement by lateral ties decreased. 2) As the ties spacing decreased from 100mm to 30mm, the magnitude of axial load acting on the concrete column showed an enhancement of 1.1~1.2 times and the descending curve after a peak moment presented a smooth decline. 3) The high-strength concrete columns required a design of lateral ties to increase the volumetric ratios and density of tie spacing to sustain a proper strength and ductility. Accordingly, regardless of concrete strength, the current AIK design code to specify the maximum tie spacing of concrete columns was proven to lead to the poor strength and ductility for seismic design. Therefore, it is necessary to develop a new seismic design code that connects volumetric ratios and tie spacing of concrete columns with concrete strength.

• Tuberculosis and Respiratory Diseases
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• v.56 no.5
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• pp.485-494
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• 2004

Background : To assess the effects of mDOT implementation on sputum smear conversion for AFB (Acid fast bacilli) positive pulmonary tuberculosis patients, modified Directly Observed Treatment (mDOT) was started on October $8^{th}$ 2001 at a health center in Seoul. mDOT was defined through weekly interviewing and supervising of a patient by a supervisor (doctor, nurse, or lay health worker). The sputum smear conversion of a mDOT group was compared with that of a self-medication (self) group. Methods : This study included 52 AFB positive pulmonary tuberculosis patients registered at a health center in Seoul between October $8^{th}$ 2001 and April $23^{rd}$ 2002. 24 and 28 patients were enrolled in the mDOT and self medication groups, respectively. Paired (1:1) individual matching, by gender, extent of disease, relapse and age-matching variables, was performed between the two groups, resulting in 20 paired matches. This prospective study was planned as an unblinded, non-randomized quasiexperimental pilot project. Outcomes were identified from results of sputum smear examinations for AFB in both groups at 2 weeks, and 1 and 2 months. The paired matching data were analyzed using the SAS program version 8.1 by McNemar test. Results : At the end of 2 weeks of treatment, the sputum smear conversion of the mDOT group was somewhat higher than that of the self medication group (78.57 vs. 50%, p-value=0.289), and after 1 month of treatment no statistically significant difference was shown between the two groups (83.33 vs. 50, p-value=0.125). At the end of 2 months of treatment (initial intensive phase), the sputum smear conversions of the mDOT and self groups were 95 and 75%, respectively (p-value=0.219). Conclusions : The implementation of mDOT did not result in clinically significant increases in the sputum smear conversion at 2 weeks, and 1 and 2 months compared with that of the self medication group. However, the increases experienced might contribute to diminishing the infectious period of AFB positive patients, and this approach may act as a guide for a specific group of patients. In this study, mDOT was performed for one hundred percent of the intensive treatment phase. It can also be an effective treatment for pulmonary tuberculosis patients, and may be useful for some high risk tuberculosis patients.

• Korean Journal of Ecology and Environment
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• v.43 no.1
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• pp.129-135
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• 2010

The relationship between rainfall variable and zooplankton dynamics was studied in the Upo wetland, an ecosystem of international importance. Water sampling was conducted on biweekly basis from January 2002 to December 2007 in the study site. The annual average of total rainfall was 1,324 mm during the study period. Total rainfall amount in 2003 (1,766 mm) was unusually high, while total rainfall amount in 2005 (975 mm) was exceptionally lower than the average. Most of basic limnological parameters (water temperature, dissolved oxygen, pH, conductivity and turbidity) in the study site were greatly influenced by the flooding events and rainfall amounts in summer. There were statistically significance between seasonal and inter-annual differences in zooplankton abundance and the total rainfall amount (ANOVA, P<0.05). Zooplankton abundance was high in summer (mean${\pm}$s.d.: $1,594{\pm}1,598\;Ind.\;L^{-1}$) and low in winter ($246{\pm}234\;Ind.\;L^{-1}$. The 47% of annual total zooplankton abundance in the study site were observed in summer. The seasonal pattern of rotifers was similar to that of total zooplankton. This reflected the fact that rotifers strongly dominated and occupied ca. 65% the total zooplankton abundance (annual mean: $398{\pm}1,139\;Ind.\;L^{-1}$, n=149), followed by cladocerans ($65{\pm}140\;Ind.\;L^{-1}$) and copepods ($58{\pm}84\;L^{-1}$). Planktonic rotifers such as Keratella cochlearis, Polyarthra spp. and Brachionus calyciflorus were dominant from winter to spring and attached rotifers such as Lecane spp., Monostyla spp. and Trichocerca spp., observed commonly from spring to fall. Among the environmental variables considered, rainfall in summer seemed to play the most important role in determining characteristics of zooplankton community dynamics in the Upo wetland.