• Journal of Electrical Engineering and Technology
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• v.4 no.3
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• pp.310-314
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• 2009

This paper presents the improvement of the voltage profiles of power system networks by the inclusion of Unified Power Flow Controller (UPFC). The mathematical model of the UPFC is incorporated in the load flow algorithm and the L-index is calculated for the different values of the control parameter r $and{\gamma}$. The positioning of the UPFC device is changed to minimize the sum of the squares of the L-indices at all load buses. The test cases considered for the improvement of voltage profile with the WSCC 9-bus and IEEE 30 bus system. With the best position of UPFC along with the control parameters the improvement in voltage profile of the power system networks are obtained. The results obtained are quite encouraging compared with other techniques used to identify the best location of UPFC.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.719-723
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• 2002

The purpose of this study is to suggest the correlation of single-number ratings for sound insulation by floor impact. As a assessment method of impact sound insulation. we selected the IIC contour of ISO, A weighted sound level. Inverse A-weighting curve and L-Index of japanese industrial standard. And we estimated the single-number ratings by application the measured data of impact sound level to each method. The results showed that the coefficients of determination between each two single-number ratings were very high (more than 0.9169). And In the condition of same assessment method, the coefficient of determination for light-weight impact sound was higher than that for heavy-weight impact sound.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.1132-1136
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• 2004

본 논문은 지금까지의 지점빈도해석의 약점을 보완하기 위하여 지역화의 개념을 사용한 지역빈도해석의 방법에 관한 연구이다. 지점빈도해석은 수문자료의 관측기간이 짧은 경우 정확도에 문제를 발생시킬 수 있으므로, 지점 내 충분한 수의 자료 확보가 선행되어야 한다. 반면 지역빈도해석의 경우 우리나라와 같이 자료의 수가 부족한 경우에도 효율적이고 안정적인 확률수문량을 산정할 수 있다. 본 연구에서는 한강유역의 강우자료 선별을 통해 신뢰성 있는 자료를 구축한 훈, L-모멘트기법과 Netmax법을 사용한 지역빈도해석을 각각 실시하여 기존의 방법으로 산정한 수문량과 비교${\cdot}$분석하였다. 지역빈도해석의 결과 남한강 유역은 이질성 척도가 큰 것으로 판명되어 남한강 유역의 경우 지역적인 세분화가 필요한 것으로 나타났다. Netmax를 이용하여 산정된 수문량은 L-모멘트법과 지점빈도해석 그리고 확률강우량도에 의해 산정된 값에 비하여 과소추정 되었다 지역적 특수성을 고려하지 않고 형성된 네트워크는 지역적으로 세분화가 필요한 지역에 대하여서 좋지 않은 결과를 보여주는 것으로 나타났다.

• Structural Engineering and Mechanics
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• v.12 no.3
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• pp.341-346
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• 2001

Near source earthquakes can be characterized not only by strong horizontal but also by strong vertical ground motions with broad range of dominant frequencies. The inelastic horizontal response of thin-walled L-shaped steel bridge piers, which are popularly used as highway bridge supports, subjected to simultaneous horizontal and vertical ground excitations of near source earthquakes is investigated. A comprehensive damage index and an evolutionary-degrading hysteretic model are applied. Numerical analysis reveals that the strong vertical excitation of a near source earthquake exerts considerable influences on the damage development and horizontal response of thin-walled L-shaped steel bridge piers.

• Honam Mathematical Journal
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• v.45 no.3
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• pp.542-554
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• 2023

Given a real number α, the Lagrange number of α is the supremum of all real numbers L > 0 for which the inequality |α - p/q| < (Lq²)^-1 holds for infinitely many rational numbers p/q. All Lagrange numbers less than 3 can be arranged as a set {l_p/q : p/q ∈ ℚ ∩ [0, 1]} using the Farey index. The present paper considers a function C(α) devised from Sturmian words. We demonstrate that the function C(α) contains all information on Lagrange numbers less than 3. More precisely, we prove that for any real number α ∈ (0, 1], the value C(α) - C(0) is equal to the sum of all numbers 3 - l_p/q where the Farey index p/q is less than α.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.2
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• pp.79-87
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• 2010

Objectives: The purpose of this study was to investigate the symptoms of work-related musculoskeletal disorders (WMSDs), the influence of the WMSDs on the health-related quality of life (HRQoL), and to identify the differences of WMSDs and HRQoL between greenhouse farmers and paddy farmers. Methods: Subjects were 34 greenhouse farmers and 56 paddy farmers who were living in a rural community. The sociodemographic characteristics, health-related behavior, working characteristics, WMSDs and HRQoL were investigated. WMSDs symptoms were measured by a selfassessed questionnaire on musculoskeletal disorders symptoms and HRQoL was measured by the Euro Quality of Life (Euroqol) EQ-5D index. The differences on the WMSDs, EQ-5D and it's related factors between the groups were assessed with t-test and ${\chi}^2$-test. Results: Greenhouse farmers were longer the working hours per day and working duration than paddy farmers. The level of prevalence of the WMSDs in greenhouse farmers is higher than in paddy farmers. The EQ-5D index of greenhouse farmers and paddy farmers were 0.819 and 0.874, respectively. Overall, the mean value of EQ-5D index was significantly lower greenhouse farmers than paddy farmers. Conclusions: These results showed that the HRQoL for farmers are strongly influenced by WMSDs and agicultural type in that we are aware of the need to comply with regulations of WMSDs, especially greenhouse farmers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.7034-7042
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• 2015

The purpose of this study was to investigate the effects of metabolic syndrome(MS) on quality of life(QoL) using the Korea National Health and Nutrition Examination Survey of 2013. We analyzed data for 4,890 adults, aged 19 year or older and provided the correct data about MS and QoL. MS was defined by the National Cholesterol Education Program-Adult Treatment Panel III with Korea-specific waist circumference cutoffs and QoL was measured by the EuroQol 5-dimension(EQ-5D). The prevalence of MS was 22.1% and high density lipoprotein(HDL)-cholesterol was the highest prevalence in MS components. The mean of EQ-5D index was significantly lower in subject with MS compared to subjects without MS. Among MS components, only higher waist circumference led to EQ-5D index decreasing and the regression coefficient was -0.018. In conclusion, we suggest the attention to QoL and intervention program for improving the QoL in subjects with MS.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.6
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• pp.995-999
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• 2004

Effects of liquefied calcium supplement on bone mineral density (BMD) and bone health index (osteocalcin, deoxypyridinoline) were investigated in 12 middle aged women. Middle aged women were arranged into 3 groups such as control, Ca500 and Ca750 by liquefied calcium supplement level. BMD was measured at the spine (vertebrae L2-L4). After 6 month, BMD of control group dropped but that of Ca750 were increased from 0.850 to 0.865. The increase in serum calcium and osteocalcin level, and the decrease in urine deoxypyridinoline level were observed in by calcium supplement groups. The bone health index of serum was changed as much as level of calcium supplement. The serum osteocalcin level of Ca750 significantly increased to 7.93 ng/mL after 6 months of calcium supplement. Although we didn't get any significant difference in BMD, we found that the liquefied calcium had no side effect and led effective change in bone health index. Hereafter, we suppose that the liquefied calcium will be available to develop healthy products for preventing osteoporosis.

• Parasites, Hosts and Diseases
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• v.59 no.5
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• pp.473-479
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• 2021

A nationwide survey of chigger mites causing scrub typhus and an investigation of epidemiologic factors for chigger mites was conducted at 16 localities in 8 provinces in Korea during autumn 2009, 2012, and 2013. A total of 233 Apodemus agrarius were captured, and all were infested with chigger mites. The chigger index was highest in Chungcheongbuk-do in 2009 (358.3) and 2012 (290.1) and Chungcheongnam-do in 2013 (294.4). The predominant chigger mite species was Leptotrombidium pallidum in the northern and central parts and L. scutellare in the southern and western parts, Korea. L. pallidum was not found in Jellanam-do and Gyeongsangnam-do and the distribution of L. scutellare had been expanded in the northern parts of Korea. The chigger index of L. pallidum was positively correlated with temperature and negatively correlated with humidity. The incidence of scrub typhus is dependent on L. scutellare index. These findings could be helpful to monitor the distribution of chigger mites and to develop a preventive measures for scrub typhus in Korea.

• Korean Journal of Community Nutrition
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• v.29 no.4
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• pp.336-347
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• 2024

Objectives: This cross-sectional study examined sex differences in Health-Related Quality of Life (HRQoL) among seniors with Type 2 Diabetes Mellitus (T2DM). Methods: Data from the Korea National Health and Nutrition Examination Survey (2008-2020) were analyzed. The EuroQol-5 Dimensions (EQ-5D), a measure of HRQoL, was used. It comprises five dimensions: mobility, self-care, usual activity, pain/discomfort, and anxiety/depression, each with three levels. Results: Analysis of 3,826 older adults with T2DM showed a significant increasing trend in the EQ-5D Index from the 4th survey phase onwards (P for trend < 0.001 for both men and women). Men consistently reported higher EQ-5D levels than women across all survey years. Women's EQ-5D levels remained lower than men's, maintaining a decade-old disparity (P < 0.05). Men scored significantly higher (P < 0.05) in most EQ-5D domains, except for self-care and anxiety/depression, resulting in a higher total EQ-5D Index (P = 0.001). Increased comorbidities were strongly associated with lower EQ-5D levels in both sexes. Additionally, there was a negative correlation between the EQ-5D Index and refined grain intake for both sexes (P for trend < 0.001), with high-EQ-5D groups consuming fewer refined grains. Women in the high-EQ-5D group consumed more nuts, vegetables, and meat compared to men (P for trend < 0.05). Conclusions: Our study highlights the sex disparities in HRQoL among older adults with T2DM. The findings suggest the need for tailored treatment guidelines aimed at improving the HRQoL of elderly T2DM patients, with a focus on their sex-specific characteristics. Implementing these tailored guidelines could enhance the HRQoL of older women with T2DM and promote more equitable healthcare outcomes. This underscores the importance of considering sex differences to comprehensively improve the well-being of this population.