• The korean journal of orthodontics
• /
• v.27 no.1
• /
• pp.91-103
• /
• 1997

This paper aimed to study what the influences of orthodontic treatment of pronunciation are. We compared the duration and the acoustic wave patterns of Korean consonants pronounced by a control group with those of a patient who had his four premolars extracted and had been given orthodontic treatment The results were as follows : 1. Compared to the control group, the treatment group had a longer duration time of consonant pronunciation for all consonants but "ㅅ(s)" and "ㅌ($(t^h)$" in CV(consonant-vowel) pairs. Especially in the case of "ㅈ(dz)", "ㅆ$({\varphi}^h)$" for CV-pairs, and "ㄷ(d)" in VCV(vowel-consonant-vowel) clusters, the duration of consonant sound showed a sharp contrast between the control group and the treatment group. 2. There were clear differences in the acoustic wave patterns of "ㅉ(ts)", "ㅆ$({\varphi}^h)$" and "ㅊ$(c^h)$", all of which were in VCV-clusters. The acoustic wave pattern of "ㅉ(ts)", when pronounced by the treatment group, was stronger than the control group's. This phenomenon was most remarkable in the transitive section where the "ㅉ(ts)" sound flowed into the following vowel. When a preceding vowel shifted to the consonant "ㅆ$({\varphi}^h)$", the attack property of the appeared clearly in the acoustic waves of the treament group, while in the control group the starting point of consonart was indistinctive. Consonant duration for the treatment group was longer, and the appearance of a zero crossing point in the acoustic wave was more frequent. In the case of "ㅊ$(c^h)$", the treatment group produced a strong acoustic wave, and the property of aspiration was obvious in it. 3. When the treatment group pronounced "ㄷ(d)" and "ㅈ(dz)" in CV-pairs, the acoustic-wave was similar to that of aspirated "ㅌ$(t^h)$" and "ㅊ$(c^h)$". 4. The aspirated "ㅌ$(t^h)$" and "ㅊ$(c^h)$" pronounced by the treatment group showed the stronger airstream and acoustic wave form.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.3 no.1
• /
• pp.80-85
• /
• 2011

For the assessment of statistical characteristics of wave loads in the real sea state, the probability distribution of wave loads are computed based on the sufficient duration of computations in irregular waves. First of all, the estimation of wave impact loads is well modified applying the displacement potential formulation, which was proposed by one of authors, for solving Wagner's flow model. Consequently, the present computation method is also modified. Prior to the computation in irregular waves, preliminary computation to determine the adequate number of realization of irregular waves is examined. The effect of hull girder vibration on the statistical characteristics is examined by means of the computation with/without hull girder vibration. It is found that hull girder vibration has a certain effect on the probability of occurrence of wave loads. Furthermore, computations taking account of the effect of operation, that is the effects of ship speed and course change, is conducted for the rational evaluation of the effects of hull girder vibration. It is clarified that the effect of operation on the statistical characteristics of wave loads is significant. It is verified that the evaluation without the effect of operation may overestimate the effect of hull girder vibration.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.9 no.3
• /
• pp.1-8
• /
• 1972

The characteristics of tunnel diode pair circuit biased within the negative resistance region has also the voltage-control type negative resistance region, and the voltage at the center point of negative resistance region is described as the square-wave relaxation oscillation. In this paper, the period T, positive duration T1, negative duration T2 of the pulse are obatined from the characteristic curve T, positive duration T1, negative duration T2 of the pulse are obtained from the characteristic curve and observed actually, considring the fact that the pulse width and the period of square-wave at the center point of the negative resistance region is able to be controlle dby the blas volgate. Mereover, the relationship between T, T1 or T2 and circuit parameters is searched for and the Circuit parameters that satisfy the conditions of T1-T2 being proportional to the variation of bias voltage with Teonstant are determined. Thereafter, the bias voltage and the signal voltage are inserted serially to the PWM circuit and the characteristics of that circuit is analyzed.

• Journal of Korea Water Resources Association
• /
• v.54 no.9
• /
• pp.693-704
• /
• 2021

The purpose of this study is to evaluate the relationship between heat wave and river water quality. The daily maximum air temperature (Tmax) of 91 meteorological stations of the Korea Meteorological Administration and 13 river water quality factors (DO, BOD, COD, TOC, TN, DTN, NH4-N, NO2-N, NO3-N, TP, DTP, PO4-P, Chl-a) of Ministry of Environment were analyzed. The correlation analysis was performed on Tmax and water quality factors, and the determination coefficients (R²) of DO, Chl-a, and TN with Tmax showed high values of 0.782, 0.609, and 0.691 respectively. To analyze the spatial impact between heat waves and water quality factors, the heat wave intensity (HWI) and heat wave duration (HWD) were calculated using the Tmax. The hotspot and spatial statistical analyses were applied for spatial impact evaluation. As a result of hotspot analysis, the heat wave index (HWD, HWI) showed high spatial pattern in the downstream of Nakdong River basin, and Chl-a and TN showed the same pattern. In case of spatial statistical analysis for water quality due to heat wave, the most obvious spatial variability was DO.

• Journal of Korean Foot and Ankle Society
• /
• v.6 no.1
• /
• pp.80-85
• /
• 2002

Purpose: This study is to assess the involvement of vessels in lower extremity in diabetics, using color doppler ultrasonogram. Materials and Methods: Arteries of both lower extremities were divided into 3 groups-large vessel (above-knee arteries), popliteal vessel, and small vessel(below-knee arteries) -, and evaluated using color doppler ultrasonogram in 60 diabetics. In color doppler ultrasonogram, the wave forms of all vessels were divided into 5 grades; grade I was triphasic wave form, grade II was spectral broadening form, grade III was monophasic wave form, grade IV was pulsus tardus et parvus form, grade V was absence of wave. Grade III, IV, V were grouped into vessel obstruction. We reviewed the correlationships among the degree of the peripheral vascular involvement, duration of dibetes, existence of bilaterality, types of dibetes. Results: Bilateral involvement was high in both lower extremity. Luminal stenosis, vascular calcification and vessel obstruction were high incidence in the patients over ten years of diabetic duration. Prevalence of vascular calcification and vessel obstruction were high in the small vessel of ankle level. But, insulin injection was not related to the incidence of vascular abnormality. Conclusion: Color doppler ultrasonogram seems to be useful for evaluation of peripheral vascular status, decision making for necessity of additional test, periodic follow -up tool in diabetes patients.

• Water for future
• /
• v.21 no.4
• /
• pp.389-397
• /
• 1988

For determination of the design wves at the seven selected sites in the South Sea, a method of hindcasting the past annual largest significant waves from the records of both the wind speed at the nearby weather stations and the weather charts of typhoons are utilized. The design significant waves in deep water are determined through the extremal probability analysis for three major wave directions(SW, S, SE) at each site from the annual extremal series of wave heights. Design significant wave heights with the return period of 100 years ranged between 4.6m and 8.8m with the wave period ranging between 8.2 seconds and 12.9 seconds. Through the analysis of weather maps, both the fetches for the wind directions SW-SE along the South Coast and the relationship between the wind speed at sea and the wind speed at the nearby land weather stations for seasonal winds are determined. The wind speed at sea are found to be 0.8-0.9 times the wind speed at the land stations for $U_1$>15m/s. The ratio of the duration-averaged wind speed to the maximum wind speed varies between 0.7-0.9 as a negative exponential function for the duration ranging 2< t< 13 hours.

• Korean Journal of Child Studies
• /
• v.38 no.2
• /
• pp.191-204
• /
• 2017

Objective: The purpose of this study was to explore the structural relationships among duration of media use, behavior problems, and school adjustment, while accounting for gender differences. Methods: The study used 4th-wave panel data from the Korean Children and Youth Panel Study, and 2,119 first graders in elementary school were analyzed. The data were analyzed using Structural Equation Modeling. Results: The results can be summarized as follows. First, the duration of media use had a direct effect on school adjustment. Secondly, the duration of media use had an indirect effect on school adjustment through internalizing and externalizing problems. According to multigroup analysis, gender differences were found in the structural relations among variables. Conclusion: This study emphasizes the needs for media usage education to improve children's school adjustment. Furthermore, it suggests that different intervention strategies for internalizing/externalizing behavior problems are needed depending on gender.

• Journal of the Society of Naval Architects of Korea
• /
• v.40 no.5
• /
• pp.60-67
• /
• 2003

For risk or reliability assessment of ship structures against particular hazardous situations such as total loss or sinking due to hull girder collapse, the short-term based response analysis rather than the long-term response analysis is required to determine wave-induced bending moments when the ship encounters a storm of specific duration and with a specified small encounter probability. In the present study, the effects of operational condition and sea states on wave-induced bending moments of large merchant vessels are investigated. A series of the short-term response analyses for a hypothetical VLCC and a Capesize bulk carrier (CSBC) are carried out with varying operational condition and sea states which include ship speed, significant wave height and wave persistence time, using the linear-strip theory based program ABS/SHIPMOTION and the MIT sea-keeping tables. The computed results are also compared with the IACS design formula predictions. The results and insights developed from the present study are summarized.

• Korean Journal of Child Studies
• /
• v.37 no.3
• /
• pp.13-26
• /
• 2016

Objective: The purpose of this study was to investigate the relationship between sleep duration and school adjustment of elementary-, middle-, high-school youth and to verify the mediating effects of parenting behavior. Methods: We analyzed the data from Wave 4 of the first-grade panel of elementary school and Waves 1 and 4 of the first-grade panel of middle school in Korean Children and Youth Panel Survey (KCYPS), including 1,703 fourth graders, 2,119 seventh graders, and 2,108 tenth graders. Multiple regression was used for the data analyses. Results: The results of this study were as follows. First, longer sleep duration was associated with a higher level of school adjustment in fourth grade. In contrast, longer sleep duration was associated with a lower level of school adjustment in seventh and tenth grades. Second, longer sleep duration was related to a higher level of discipline through reasoning in fourth grade. However, longer sleep duration was related to a lower level of parental monitoring in seventh and tenth grades. Third, the relationship between sleep duration and school adjustment was mediated by parenting behavior. Discipline through reasoning had a mediating effect in fourth grade, but the mediating effect of parental monitoring was found in seventh and tenth grades. Conclusion: These results suggest a differentiated approach on sleep duration in accordance with developmental stage and the need for parent education.

• Korean Journal of Social Welfare Studies
• /
• v.44 no.3
• /
• pp.301-322
• /
• 2013

By analyzing wave 1~11 (1998~2008) of Korean Labor and Income Panel Study(KLIPS) database, this study examines the effects of household characteristics and poverty duration on poverty exit. A special concern is to decide whether the decrease of poverty exit rates comes from true duration dependency or from the sample heterogeneity as poverty duration progresses. I also analyzed how the effects of independent variables are changed when unobserved heterogeneity is controlled. The results show that duration dependency disappears after controlling observed household characteristics and unobserved individual heterogeneity. This finding confirms that the apparent relationship between poverty exit rate and poverty duration is in fact a spurious association due to the sample heterogeneity rather than true duration dependency. In addition, the effects of household characteristics on poverty exit rate become more stronger when unobserved heterogeneity is controlled. Socioeconomic factors affecting poverty exit rates are such as householders' age, education, household composition, number of family members, labor force participation, and work status.