• 한국어류학회지
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• 제33권2호
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• pp.64-73
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• 2021

본 연구는 2015년 1월부터 12월까지 한국 주변해역에서 대형선망어업으로 어획된 고등어의 성장과 연령구조를 분석하였다. 연령분석을 위해 총 459개의 이석이 사용되었고, 가랑이체장의 범위는 19.6~46.0 cm였다. 연령은 투명대의 수, 채집일, 이석 가장자리 형태, 1월 1일의 명목생일에 대한 정보를 이용하여 판독하였다. 윤문은 고등어의 산란시기인 5월에 형성되었다. 연령은 0세부터 6세까지 추정되었고, von Bertalanffy 성장식은 성별 간 유의한 차이가 나타나지 않았다. 암컷과 수컷을 모두 합한 성장식은 FL_t=39.3×{1-exp[-0.90×(t+0.033)]}으로 도출되었다. 2015년 대형선망 어획물의 연령구조를 살펴본 결과, 2세군의 어획비율이 30.9%로 가장 높았고, 0~2세군은 전체 어획물의 88.5%로 대부분을 차지하였다.

• Journal of applied mathematics & informatics
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• 제24권1_2호
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• pp.49-64
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• 2007

In this paper, we investigate optimal policies for three age-dependent populations in a competition system, which is controlled by fertility. By using Dubovitskii-Milyutin's general theory, the maximum principles are obtained for problems with free terminal states, infinite horizon and target sets, respectively.

• The Korean Journal of Ecology
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• 제16권3호
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• pp.305-316
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• 1993

Stands profiles, yearly changes in growth of annual rings, age and diameter structure, and spatial distribution pattern of individuals in the Pinus densiflora stands around the Yeocheon industrial complex were investigated. Growth of annual ring in Pinus densiflora, which survived when vegetation of this area was damaged by air pollutants, was suppressed for about 10 years since 1974 when factories in this area began to operate, but since then such suppressed growth tended to be recovered. It was supposed that the suppresed growth was originated from air pollution and that improvement of growth since the suppressed period was due to the release from competition with them by death of neighbouring trees and the resuction of the amount of air pollutants. Physiognomy of Pinus densiflora stands showed mosaic pattern composed of different patches. Spatial distribution pattern of individuals an stand profiles were similar to those of Pinus densiflora stands regenerated after natural and artificial disturbances. In an age distribution diagram, age of Pinus densiflora population ranged from 1 to 33 years, Among these individuals were recrited corresponded to the suppresed period of growth of annual ring in Pinus densiflora survived when the vegetation was damaged by air pollution. On the other hand, from the result of analysis of frequency distribution diagram of diameter, it was postulated that even if whis Pinus densiflora community can be maintained as it is for the time being, it might be changed to Quercus community with the lapse of time.

• 말소리와 음성과학
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• 제7권2호
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• pp.63-73
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• 2015

This study investigated longitudinally early vocalization and phonological developments of typically developing children. Ten typically developing children participated in the study from 9 months to 18 months of age. Spontaneous utterance samples were collected at 9, 12, 15, 18 months of age and phonetically transcribed and analyzed. Utterance samples were classified into 5 levels using Stark Assessment of Early Vocal Development-Revised(SAEVD-R). The data analysis focused on 4 and 5 levels of vocalizations classified by SAEVD-R and word productions. The percentage of each vocalization level, vocalization length, syllable structures, and consonant inventory were obtained. The results showed that the percentages of level 4 and 5 vocalizations and word significantly increased with age and the production of syllable structures containing consonants significantly increased around 12 and 15 months of age. On average, the children produced 4 types of syllable structure and 5.4 consonants at 9 months and they produced 5 types of syllable structure and 9.8 consonants at 18 months. The phonological development patterns in this study were consistent with those analyzed from children's meaningful utterances in previous studies. The results support the perspective on the continuity between babbling and early speech. This study has clinical implications in early identification and speech-language intervention for young children with speech delays or at risk.

• 가정과삶의질연구
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• 제11권1호
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• pp.191-202
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• 1993

The purpose of this study was to investigate the degree of father's participation on child-rearing in relation to parents' sex-role streotypes and conjugal power structure and backg-round factors(children's sex paternal aged and educational level. maternal employment status and family's socio-economic status) The subjects of the study 368 couples who have preschoolers. The main study was conducted from sep. 17 to Oct. 2. 1992 using a set of questionaires which has been revised after a pilot study of 38 couples Statistical method for data analysis were frequencies percentiles means ANOVA Duncan's multiple range test F-Test and Cronbach's a. The results indicated 1) That There were significant differences in the degree of father's participation on child-rearing in term of children's sex parternal age the parents' sex-role streotypes the type of conjugal power structure. 2) that the variables which have significant effects on the degree of father's participation of child-rearing were conjugal power structure mother's sex-role types and father's age.

• The Journal of Asian Finance, Economics and Business
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• 제8권5호
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• pp.287-292
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• 2021

The article analyzes the impact of capital structure on the firm value of chemical companies listed on the stock market of Vietnam. Data was collected from the financial statements of 23 chemical firms listed on the Vietnam stock market from 2012 to 2019. Quantitative research method with regression model according to OLS, FEM, REM method is used; FGLS method is used to overcome the model's defects. In this research, firm value (Tobin's Q) is a dependent variable. Capital structure (DA), Return on assets (ROA), Asset turnover (AT), fixed assets (TANG), Solvency (CR), Firm size (SZ), Firm Age (AGE), and revenue growth rate (GR) are independent variables in the study. The analysis results show that the capital structure of firms in the chemical industry listed on the Vietnam stock market has an inverse correlation with firm value. Besides, firms with greater asset turnover, business size, and number of years of operation have lower firm value. This article helps corporate executives improve corporate value by adjusting their capital structure properly. Chemical firms adjusted their capital structure in the direction of gradually decreasing the debt ratio and gradually increasing equity. Firms use high debt, which has the effect of reducing the firm value of firms in the chemical industry.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.42.1-42
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• 2002

A model to predict population by sex, age and district over a long-range period is proposed based on fuzzy theories. First, a fuzzy model is described. Second, a method to estimate the social increase by sex and age in each district is proposed based on a fuzzy clustering method for dealing with long-range socioeconomic changes in population migration. By the proposed methods, it became possible to predict the population by sex, age and district over a long-range period. Third, the structure and characteristics of the three models of employment model, time distance model, and land use model constructed to predict various socioeconomic indicators, which are require...

• 아동학회지
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• 제12권2호
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• pp.130-145
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• 1991

The purpose of this study was to investigate parental authority by sex and age of child. The subjects of this study were 546 elementary school and middle school children in Seoul. The instrument was the Parent Authority Scale (김경희, 1991). Statistical analysis of the data was by two-way multivaliate analysis of variance, simultaneous confidence interval and structure coefficients. There were sex and age differences in children's perception of parental authority. There was a significant interaction effect between children's sex and age on parental authority.

• Journal of Forest and Environmental Science
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• 제30권1호
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• pp.101-106
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• 2014

The purpose of this research was to figure out the stand structure and growth characteristic with relation to DBH, height, and volume in sixteen Pinus koraiensis plantations of Gangwon province region. Age class was diversely distributed from age class II (16 yr) to age class VIII (77 yr), and, in terms of site index, sixteen regions were superior: nine regions 'high', seven regions 'middle'. The distribution of DBH by sites appeared a bell-shaped curve, and the number of trees was the most in diameter section of 18-22 cm. The dispersion of DBH was various with age and widest ranging from 18 cm to 58 cm in age class VII-VIII. The distribution of height was also a bell-shaped curve with the smaller deviation than the distribution of DBH, and most of trees were in height section of 14-18 m. The correlation of DBH and height was high (r=0.75), and the volume bigger than 1.0 $m^3$ was presented from DBH 35 cm, height 20 m.

• 대한기계학회논문집B
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• 제23권5호
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• pp.661-669
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• 1999

The evolutionary structure of a tip vortex in the initial period have been investigated by the two-dimensional LDV system. Circumferential and axial components of mean velocities, their turbulences and Reynolds stresses were measured by the phase averaging technique at seven different wake ages within one revolution of the rotor. Core growth was also analyzed. It was resulted that circumferential velocity components showed a Rankine combined vortex shape and their circulation profiles viewed in the radial direction were close to the n = 2 model of Vatistas' algebraic formula, while axial velocity components seemed to have the Gaussian profiles In these measured ranges with the base width of three times of core radii. Peaks of circumferential velocities and core radii showed distinct asymmetric behaviors before the wake age of $150^{\circ}$ over inboard and outboard sides of the slipstream, but they became symmetric afterwards. Turbulence profiles which had two peaks Inside the core radii in the earlier wake age were also changed to single peaks after $150^{\circ}$. These trends imply that the tip vortex was barely mature at this wake age.