• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.4
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• pp.291-298
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• 2024

As an important fishing ground in the southern coast of Korea, Jinhae Bay is characterized by a high level of fisheries production. However, its marine-ecosystem has shifted owing to environmental changes such as industrial development and high water temperatures over the decades. This study analyzes the fisheries production, discards, mean trophic level, and fishing-in-balance index using annual fishing data from five regions surrounding Jinhae Bay for the period 2005-2022, as well as using additional forecasting trends by 2027 using ARIMA (Auto Regressive Intergrated Moving Average). The results shows, that the production in Goseong will decrease continuously by 2027, as compared with that in other areas. Additionally, byproduct management is considered necessary in Tongyeong. For the marine-ecosystem index, Tongyeong indicates stable catch ratio of large fish species and a fishing-in-balance exceeding 0. Finally, the annual catch variation for six pelagic fish species in Jinhae Bay by 2060 is estimated based on the IPCC climate-change scenario, in which the recent low level that decreased to approximately 20 thousand ton in early 2020 is projected to recover to approximately 40 thousand ton in the 2020s and 2040s, followed by an incremental decline by 2060.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.4
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• pp.1-12
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• 2024

In this study, a determination method of structural member section based on Nonlinear behaviors of steel cable-stayed bridges and the Harmony Search algorithm was presented. The Harmony Search algorithm determines the structural member section of cable-stayed bridges by repeating the process of setting the initial value, initializing the harmony memory, configuring the new harmony memory, and updating the harmony memory to search for the optimal value. The nonlinear initial shape analysis of a three-dimensional steel cable-stayed bridge was performed with the cross-section of the main member selected by the Harmony Search algorithm, and the optimal cross-section of the main members of the cable-stayed bridge, such as pylons, girders, cross-beams, and cables, reflecting the complex behavior characteristics and the nonlinearity of each member was determined in consideration of the initial tension and shape. The total weight was used as the objective function for determining the cross-section of the main member of the cable-stayed bridges, and the load resistance ability and serviceability based on the ultimate state design method were used as the restraint conditions. The width and height ratio of the girder and cross-section were considered additional restraint conditions. The optimal sections of the main members were made possible to be determined by considering the geometry and material nonlinearity of the pylons, girders, and cross-sections and the nonlinearity of the cable members. As a result of determining the optimal cross-section, it was confirmed that the proposed analysis method can determine the optimal cross-section according to the various constraint conditions of the cable-stayed bridge, and the structural member section of the cable-stayed bridge considering the nonlinearity can be determined through the Harmony Search algorithm.

• Korean small business review
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• v.31 no.4
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• pp.67-93
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• 2009

The purpose of this paper is to explore the relations between financial constraints and dividend smoothing of innovative small and medium sized enterprises(SMEs) listed on Korea Securities Market and Kosdaq Market of Korea Exchange. The innovative SMEs is defined as the firms with high level of R&D intensity which is measured by (R&D investment/total sales) ratio, according to Chauvin and Hirschey (1993). The R&D investment plays an important role as the innovative driver that can increase the future growth opportunity and profitability of the firms. Therefore, the R&D investment have large, positive, and consistent influences on the market value of the firm. In this point of view, we expect that the innovative SMEs can adjust dividend payment faster than the noninnovative SMEs, on the ground of their future growth opportunity and profitability. And also, we expect that the financial unconstrained firms can adjust dividend payment faster than the financial constrained firms, on the ground of their financing ability of investment funds through the market accessibility. Aivazian et al.(2006) exert that the financial unconstrained firms with the high accessibility to capital market can adjust dividend payment faster than the financial constrained firms. We collect the sample firms among the total SMEs listed on Korea Securities Market and Kosdaq Market of Korea Exchange during the periods from January 1999 to December 2007 from the KIS Value Library database. The total number of firm-year observations of the total sample firms throughout the entire period is 5,544, the number of firm-year observations of the dividend firms is 2,919, and the number of firm-year observations of the non-dividend firms is 2,625. About 53%(or 2,919) of these total 5,544 observations involve firms that make a dividend payment. The dividend firms are divided into two groups according to the R&D intensity, such as the innovative SMEs with larger than median of R&D intensity and the noninnovative SMEs with smaller than median of R&D intensity. The number of firm-year observations of the innovative SMEs is 1,506, and the number of firm-year observations of the noninnovative SMEs is 1,413. Furthermore, the innovative SMEs are divided into two groups according to level of financial constraints, such as the financial unconstrained firms and the financial constrained firms. The number of firm-year observations of the former is 894, and the number of firm-year observations of the latter is 612. Although all available firm-year observations of the dividend firms are collected, deletions are made in the case of financial industries such as banks, securities company, insurance company, and other financial services company, because their capital structure and business style are widely different from the general manufacturing firms. The stock repurchase was involved in dividend payment because Grullon and Michaely (2002) examined the substitution hypothesis between dividends and stock repurchases. However, our data structure is an unbalanced panel data since there is no requirement that the firm-year observations data are all available for each firms during the entire periods from January 1999 to December 2007 from the KIS Value Library database. We firstly estimate the classic Lintner(1956) dividend adjustment model, where the decision to smooth dividend or to adopt a residual dividend policy depends on financial constraints measured by market accessibility. Lintner model indicates that firms maintain stable and long run target payout ratio, and that firms adjust partially the gap between current payout rato and target payout ratio each year. In the Lintner model, dependent variable is the current dividend per share(DPS_t), and independent variables are the past dividend per share(DPS_t-1) and the current earnings per share(EPS_t). We hypothesized that firms adjust partially the gap between the current dividend per share(DPS_t) and the target payout ratio(Ω) each year, when the past dividend per share(DPS_t-1) deviate from the target payout ratio(Ω). We secondly estimate the expansion model that extend the Lintner model by including the determinants suggested by the major theories of dividend, namely, residual dividend theory, dividend signaling theory, agency theory, catering theory, and transactions cost theory. In the expansion model, dependent variable is the current dividend per share(DPS_t), explanatory variables are the past dividend per share(DPS_t-1) and the current earnings per share(EPS_t), and control variables are the current capital expenditure ratio(CEA_t), the current leverage ratio(LEV_t), the current operating return on assets(ROA_t), the current business risk(RISK_t), the current trading volume turnover ratio(TURN_t), and the current dividend premium(DPREM_t). In these control variables, CEA_t, LEV_t, and ROA_t are the determinants suggested by the residual dividend theory and the agency theory, ROA_t and RISK_t are the determinants suggested by the dividend signaling theory, TURN_t is the determinant suggested by the transactions cost theory, and DPREM_t is the determinant suggested by the catering theory. Furthermore, we thirdly estimate the Lintner model and the expansion model by using the panel data of the financial unconstrained firms and the financial constrained firms, that are divided into two groups according to level of financial constraints. We expect that the financial unconstrained firms can adjust dividend payment faster than the financial constrained firms, because the former can finance more easily the investment funds through the market accessibility than the latter. We analyzed descriptive statistics such as mean, standard deviation, and median to delete the outliers from the panel data, conducted one way analysis of variance to check up the industry-specfic effects, and conducted difference test of firms characteristic variables between innovative SMEs and noninnovative SMEs as well as difference test of firms characteristic variables between financial unconstrained firms and financial constrained firms. We also conducted the correlation analysis and the variance inflation factors analysis to detect any multicollinearity among the independent variables. Both of the correlation coefficients and the variance inflation factors are roughly low to the extent that may be ignored the multicollinearity among the independent variables. Furthermore, we estimate both of the Lintner model and the expansion model using the panel regression analysis. We firstly test the time-specific effects and the firm-specific effects may be involved in our panel data through the Lagrange multiplier test that was proposed by Breusch and Pagan(1980), and secondly conduct Hausman test to prove that fixed effect model is fitter with our panel data than the random effect model. The main results of this study can be summarized as follows. The determinants suggested by the major theories of dividend, namely, residual dividend theory, dividend signaling theory, agency theory, catering theory, and transactions cost theory explain significantly the dividend policy of the innovative SMEs. Lintner model indicates that firms maintain stable and long run target payout ratio, and that firms adjust partially the gap between the current payout ratio and the target payout ratio each year. In the core variables of Lintner model, the past dividend per share has more effects to dividend smoothing than the current earnings per share. These results suggest that the innovative SMEs maintain stable and long run dividend policy which sustains the past dividend per share level without corporate special reasons. The main results show that dividend adjustment speed of the innovative SMEs is faster than that of the noninnovative SMEs. This means that the innovative SMEs with high level of R&D intensity can adjust dividend payment faster than the noninnovative SMEs, on the ground of their future growth opportunity and profitability. The other main results show that dividend adjustment speed of the financial unconstrained SMEs is faster than that of the financial constrained SMEs. This means that the financial unconstrained firms with high accessibility to capital market can adjust dividend payment faster than the financial constrained firms, on the ground of their financing ability of investment funds through the market accessibility. Futhermore, the other additional results show that dividend adjustment speed of the innovative SMEs classified by the Small and Medium Business Administration is faster than that of the unclassified SMEs. They are linked with various financial policies and services such as credit guaranteed service, policy fund for SMEs, venture investment fund, insurance program, and so on. In conclusion, the past dividend per share and the current earnings per share suggested by the Lintner model explain mainly dividend adjustment speed of the innovative SMEs, and also the financial constraints explain partially. Therefore, if managers can properly understand of the relations between financial constraints and dividend smoothing of innovative SMEs, they can maintain stable and long run dividend policy of the innovative SMEs through dividend smoothing. These are encouraging results for Korea government, that is, the Small and Medium Business Administration as it has implemented many policies to commit to the innovative SMEs. This paper may have a few limitations because it may be only early study about the relations between financial constraints and dividend smoothing of the innovative SMEs. Specifically, this paper may not adequately capture all of the subtle features of the innovative SMEs and the financial unconstrained SMEs. Therefore, we think that it is necessary to expand sample firms and control variables, and use more elaborate analysis methods in the future studies.

• Journal of Yeungnam Medical Science
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• v.20 no.1
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• pp.62-70
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• 2003

Background: Most of all studies about the relation between the health risk and obesity are based on the European and American data. The purpose of this study is to examine the relation between adiposity and risk factors for cardiovacular disease (CVD) in normal weight individuals. Materials and Methods: Normal weight subjects with a body mass index (BMI) between 18.5 and $23kg/m^2$ (76 subjects) and overweight subjects with a BMI between 23 and $25kg/m^2$ (53 subjects) were retained for this study. Normal weight subjects were divided into three group of each adiposity variable, then three group and the overweight group were evaluated for the presence of CVD risk factors and analyze the correlation coefficients between adiposity variables and risk factors controlled for age in normal weight, overweight groups. Using logistic regression analysis, the odds ratio (OR) for the prevalence of risk factors for each group of adiposity variables and the overweight group was estimated relative to the first group in normal weight subjects. Results: Systolic BP, diastolic BP, LDL cholestrol, HDL cholesterol, triglycerides in normal weight subjects were significantly correlated with all adiposity variables (P<0.01). Third group (3.7 for %fat and 4.7 for fat mass)of adiposity variables in the normal weight group and the overweight group (6.6 for %fat and 11.5 for fat mass) tended to have higher ORs compared to first group for risk factor variables. Conclusion: Normal weight subjects with elevated adiposity had higher prevalence of risk factors than normal weights subjects with less adiposity. Measuring of adiposity added additional information of cardiovascular disease risk factors in normal weight subjects.

• Journal of Chest Surgery
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• v.43 no.6
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• pp.710-715
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• 2010

Background: Video-assisted thoracic surgery (VATS) became common in the treatment of spontaneous pneumothorax (SP). Therefor we've reviewed the recurrence rate after VATS and analysed the factors affecting recurrent pneumothorax after VATS on this study. Material and Method: This retrospective analysis was performed on 321 patients of SP who had undergone VATS from Jan. 2001 to Dec. 2008. The two groups were divided as follow: group A, non-recurrent group (298 patients: 93%); and group B, recurrent group (26 patients: 7%); the two groups were analysed retrospectively. Result: The average age of the study groups were $20.9{\pm}4.3$ years old in recurrent group vs. $25.9{\pm}11.7$ years old in non-recurrent group with statistical significance (p < 0.05). There were no statistical significance in male to female ratio, height/weight ratio, location of pneumothorax, smoking history, operative time, duration of drain, hospital stay, indication of opertion and incidence rate. Average length of duration in recurrence was 12.9 months. There was 22 (95.7%) recurrent patients after VATS within 4 year period among recurrent group. Treatment methods in 23 of recurrent patients were, 8 (VATS), 2 (Axillary thoracotomy) with 15% or more in amount of pneumothorax and 7 (7 Fr. chest tube), 6 (nasal 02) with 15% or less in amount of pneumothorax. Among 10 cases of reoperation, there were 3 cases of over looking type and 7 cases of new growing type. There was no additional recurrence after these procedures were given. Conclusion: There was higher recurrence rate in younger age after VATS thus for those under 20 yrs old, detailed and possible preoperative warning for recurrence is warranted. Most recurrence occured within 4 year period, thus for this reason, regular interval based follow up with chest x-ray study is suggested during this period.

• Korean Journal of Poultry Science
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• v.45 no.3
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• pp.183-191
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• 2018

The study was conducted to investigate the effect of dietary supplementation of Lactobacillus, medicinal plants extract, and essential oil on laying performance, cecal microflora, relative organic weight, leucocyte profiles in laying hens against Salmonella gallinarum. A total of 100 Hy-Line Brown laying hens of 65 weeks of age were assigned into 5 dietary treatments supplemented with no antibiotic (negative control), antibiotic (positive control), Lactobacillus 0.1% (LB), medicinal plants extract 100 ppm (MPE), herb extract 100 ppm (EO). After 7 days of treatment, the 20 hens in each treatment group were divided into challenge group (n=10) and non-challenge group (n=10) for oral administration of Salmonella gallinarums, and were maintained in the same dietary treatments for two additional weeks. Laying hens were selected 20 by each treatment, splitting up into oral Salmonella group and nontreated group. The feeding trial lasted for one weeks and Salmonella gallinarum was orally administered for two weeks. Egg production, egg weight, egg mass, and feed conversion ratio were calculated and cecal microflora, relative organ, and blood were collected at the end of experiment. Compared with the control, laying hens fed Lactobacillus, medical plant extract, and essential oil were not observed to change of laying performance. Salmonella count increased significantly when Salmonella gallinarum was orally administered (P<0.05) but coliform bacteria and Lactobacillus counts were not affected. The relative organs weight was not different in hens with oral administration of Salmonella gallinarum and also in hens fed Lactobacillus, medical plant extract, and essential oil. H/L ratio was not significantly different, but total leucocyte level was somewhat increased in the treatment with oral administration of Salmonella gallinarum and more leucocyte increased in laying hens fed Lactobacillus, medical plant extract, and essential oil than control.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.52-57
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• 2006

This research was carried out to determine the effect of controlling nitrogen application on tiller development, yield, and quality of rice under scanty or excess seedling stands in direct-seeded rice on flooded soil surface. Seedling stand was set to 3 levels: scanty $(60/m^2)$, optimum $(120/m^2)$, and excess $(200/m^2)$. In the scanty plot, additional 4 kg/10a nitrogen was applied at the 3rd leaf stage to promote tiller development. On the other hand, applying 3.3 kg/10a nitrogen at 5th leaf stage in the excess plot was omitted to suppress tillering. Maximum numbers of tillers per plant were 15.2 and 8.6 in scanty and excess plots, respectively, as compared with 9.8 in optimum plot. Productive tiller rate decreased with the increase in number of seedling stands. Regardless of seedling density, the first tiller developed on the 3rd node of rice stem from the bottom. The primary tillers developed at 3, 4, 5, 6, 7 nodes in scanty plot, 3, 4, 5 nodes in optimum plot, and 3, 4 nodes in excess plot. The secondary tillers developed only in some portion of plants in scanty and optimum plots. The order of tiller emergence was negatively correlated to stem length, panicle length, non-productive tiller number, grain number per panicle, and fertility in scanty plot, and to perfect grain ratio in excess plot. In the optimum plot, however, the order of tiller emergence was not correlated to any of the mentioned characteristics. The perfect grain ratio of scanty plot was the highest because green-kerneled rice was a very small portion in the primary tillers as compared with those of optimum and excess plots. Yield indexes of scanty and excess plots were 99%, and 97%, respectively, of the yield (494 kg/10a) in optimum plot. In conclusion, when seedling stands are not at optimum level, rice yield and quality similar to optimum planting density level can be obtained by means of controlling nitrogen application.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.09a
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• pp.21-36
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• 2005

Although the main geology of Korea consists of granite and gneiss, it Is not uncommon to encounter anisotropy Phenomena in crosshole radar tomography even when the basement is crystalline rock. To solve the anisotropy Problem, we have developed and continuously upgraded an anisotropic inversion algorithm assuming a heterogeneous elliptic anisotropy to reconstruct three kinds of tomograms: tomograms of maximum and minimum velocities, and of the direction of the symmetry axis. In this paper, we discuss the developed algorithm and introduce some case histories on the application of anisotropic radar tomography in Korea. The first two case histories were conducted for the construction of infrastructure, and their main objective was to locate cavities in limestone. The last two were performed In a granite and gneiss area. The anisotropy in the granite area was caused by fine fissures aligned in the same direction, while that in the gneiss and limestone area by the alignment of the constituent minerals. Through these case histories we showed that the anisotropic characteristic itself gives us additional important information for understanding the internal status of basement rock. In particular, the anisotropy ratio defined by the normalized difference between maximum and minimum velocities as well as the direction of maximum velocity are helpful to interpret the borehole radar tomogram.

• Korean Journal of Remote Sensing
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• v.34 no.3
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• pp.451-463
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• 2018

The empirical/statistical models to estimate the ground Particulate Matter ($PM_{2.5}$) concentration from Geostationary Ocean Color Imager (GOCI) Aerosol Optical Depth (AOD) product were developed and analyzed for the period of 2015 in Seoul, South Korea. In the model construction of AOD-$PM_{2.5}$, two vertical correction methods using the planetary boundary layer height and the vertical ratio of aerosol, and humidity correction method using the hygroscopic growth factor were applied to respective models. The vertical correction for AOD and humidity correction for $PM_{2.5}$ concentration played an important role in improving accuracy of overall estimation. The multiple linear regression (MLR) models with additional meteorological factors (wind speed, visibility, and air temperature) affecting AOD and $PM_{2.5}$ relationships were constructed for the whole year and each season. As a result, determination coefficients of MLR models were significantly increased, compared to those of empirical models. In this study, we analyzed the seasonal, monthly and diurnal characteristics of AOD-$PM_{2.5}$model. when the MLR model is seasonally constructed, underestimation tendency in high $PM_{2.5}$ cases for the whole year were improved. The monthly and diurnal patterns of observed $PM_{2.5}$ and estimated $PM_{2.5}$ were similar. The results of this study, which estimates surface $PM_{2.5}$ concentration using geostationary satellite AOD, are expected to be applicable to the future GK-2A and GK-2B.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.2
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• pp.241-247
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• 2012

Purpose: This study was conducted to assess the association of metabolic syndrome and its components with glaucoma. Methods: We investigated the associations of metabolic syndrome and its components (abdominal obesity, impaired fasting glucose, high blood pressure, and dyslipidemia) with glaucoma using data from 19,162 adults aged 40 or above among the Korean National Health and Nutrition Examination Survey III (2005), IV (2007-9), V (2010). The logistic regression analysis was used for assessing those associations after adjusting demographic, lifestyle, and social economic status and for assessing the association of metabolic medication intakes with glaucoma risks. Results: After adjusting for age and sex, the risk of glaucoma was significantly higher in the subjects with impaired fasting glucose(Odds Ratio (95% confidence interval): 1.78 (1.25, 2.53)) and metabolic syndrome (1.45 (1.01, 2.08)) than subjects without those. These associations increased when additional adjusting for smoking, alcohol use, regular physical activity, income, education status(impaired fasting glucose: 1.89 (1.29, 2.77), metabolic syndrome: 1.52 (1.03, 2.25)). Glaucoma prevalence was borderline significantly increased according to the number of metabolic abnormalities(age and sex adjusted p for trend = 0.055). Use of antihypertensive medication was significantly associated with the risk of glaucoma. Conclusions: Metabolic syndrome and impaired fasting glucose were significantly associated with the increased glaucoma risk. Use of antihypertensive medication was also significantly associated with the increased glaucoma risk.