• KDI Journal of Economic Policy
• /
• v.13 no.1
• /
• pp.115-134
• /
• 1991

The role of pension plans in the macroeconomy has been a subject of much interest for some years. It has come to be recognized that pension plans may alter basic macroeconomic behavior patterns. The net effects on both savings and labor supply are thus matters for speculation. The aim of the present paper is to provide quantitative results which may be helpful in attaching orders of magnitude to some of the possible effects. We are not concerned with the providing empirical evidence relating to actual behavior, but rather with deriving the macroeconomic implications for a alternative possibilities. The pension plan interacts with the economy and the population in a number of ways. Demographic variables may thus affect both the economic burden of a national pension plan and the ability of the economy to sustain the burden. The tax transfer process associated with the pension plan may have implications for national patterns of saving and consumption. The existence of a pension plan may have implications also for the size of the labor force, inasmuch as labor force participation rates may be affected. Changes in technology and the associated changes in average productivity levels bear directly on the size of the national income, and hence on the pension contribution base. The vehicle for the analysis is a hypothetical but broadly realistic simulation model of an economic- demographic system into which is inserted a national pension plan. All income, expenditure, and related aggregates are in real terms. The economy is basically neoclassical; full employment is assumed, output is generated by a Cobb-Douglas production process, and factors receive their marginal products. The model was designed for use in computer simulation experiments. The simulation results suggest a number of general conclusions. These may be summarized as follows; - The introduction of a national pension plan (funded system) tends to increase the rate of economic growth until cost exceeds revenue. - A scheme with full wage indexing is more expensive than one in which pensions are merely price indexed. - The rate of technical progress is not a critical element in determining the economic burden of the pension scheme. - Raising the rate of benefits affects its economic burden, and raising the age of eligibility may decrease the burden substantially. - The level of fertility is an element in determining the long-run burden. A sustained low fertility rate increases the proportion of the aged in total population and increases the burden of the pension plan. High fertility has inverse effects.

• Korean Journal of Poultry Science
• /
• v.37 no.4
• /
• pp.383-388
• /
• 2010

The chicken eye can discriminate light color, and different light wavelengths may affect reproduction ability. This study was carried out to identify effect of monochromatic light using light emitting diode (LED) in laying hens. Chickens were exposed to white light (WL), blue light (BL), yellow light (YL), green light (GL) and red light (RL) made by using LED as well as incandescent light (IL) (control). All light sources were equalized to a light intensity of 20 lux. The results indicated that the age of first egg laying and 50 % egg laying in laying hens treated under RL is significantly younger than under other lights (P<0.05). And the ovary weight of laying hens reared under RL is significantly heavier than under other at from 16 to 20 wks (P<0.05). The largest number of eggs production was produced in a group with treated with RL by 59 wks of age compared with any other group. The egg weight of YL was greater than other treatment groups from 26 to 45 wks (P<0.05). The egg shell from hens treated with RL was the strongest and thickest at 20 wk (P<0.05). These results suggest that the egg quality of laying hens reared in different spectrum of LED can be different and RL may enhance the laying performance.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.39 no.3
• /
• pp.64-73
• /
• 2011

This study starts from the hypothesis that the information society has affected the layman's interpretation and production of content. Specifically, the manner and contents of communication concerning the landscape of Soonyoo-do Park in blogs are surveyed and the possibilities and limitations of this phenomenon are discussed. The following topics are dealt with. Firstly, what is the landscape of Seonyoodo Park as captured by bloggers? What type of landscape do bloggers respond to? Secondly, what is the unique way that bloggers capture and interpret the landscape? Thirdly, What are the possibilities and limitations discovered from the landscape as captured and interpreted by bloggers? Thus, 1,000 blog posts concerning Soonyoo-do Park, as culled from the Internet, were categorized into three areas, First are blog posts browsed by keywords such as 'photo', 'a photographer's visit', 'a good p1ace for taking photos', and 'landscape'. These are focused on the visual aspects of the landscape. The second category is posts under the keywords 'domestic travel', 'Seoul travel', 'travel', and 'recommendation'. They contain introductory information on Seonyoodo Park; that is, they focus cm the more utilitarian functions of Seonyoodo Park as a place. The third one is posts that record personal experiences. The subjects for photography are the bloggers themselves and their companions. As a result of studying the way bloggers deal with landscape, it was found that first, people have developed the ability to capture the landscape and interpret the landscape actively and independently. This process can be regarded as the reproduction of landscape and place. In addition, the recording of their appreciation and feeling overlaps with evaluation and assumption. One negative aspect, however, is that many bloggers dramatize and repeat similar scenes. This can be seen as a make-up of image. The limitations of this study include difficulty in interpretation because blogs, which are the objects of this study, are very subjective and personal. In addition, it was not easy to categorize posts because there were diverse images and a broad range of writing. Nevertheless, practitioners of landscape architecture should continue to monitor and use one-person media like blogs, because the relationship between modern man and the landscape can be better understood through them.

• Microbiology and Biotechnology Letters
• /
• v.8 no.3
• /
• pp.199-206
• /
• 1980

Some experiments on the citric acid production were carried out from soluble starch and molasses as raw materials. When soluble starch was used as substrate for the fermentation of citric acid by the strain M-80 which had assimilating ability of soluble starch in surface culture, the optimal culture media was 120g of soluble starch, 3.0g of (N $H_4$)$_2$S $O_4$, 2.0g of K $H_2$P $O_4$, 0.2g of MgS $O_4$.7$H_2O$, 1.5mg of F $e^{++}$, 1mg of Z $n^{++}$ and 20ml of methanol were added to 1 liter and optimal pH was 5.5. In about 8 days 61.8mg/ml of citric acid was produced. When treated molasses with potassium ferrocyanide was used as substrate for the fermentation of citric acid by the strain of M-315, the optimal condition in surface culture was 250g of molasses, 0.3g of N $H_4$N $O_3$, 0.05g of K $H_2$P $O_4$, 0.01g of MgS $O_4$.7$H_2O$, 0.5g of Potassium ferrocyanide and 30ml of methanol were added to 1.0 liter. On the other hand, the optimal condition in submersed culture was 250g of molasses, 0.3g of N $H_4$N $O_3$, 0.1g of K $H_2$P $O_4$, 0.01g of MgS $O_4$.7$H_2O$, 0.5g of potassium ferrocyanide, and 30m1 of methanol were added to 1.0 liter and optimal pH was all 5.0. After 9 days culture, 69.4mg/ ml, 39.6mg/ml of citric acid were separately produced in surface and submerged culture media.dia.

• Microbiology and Biotechnology Letters
• /
• v.29 no.3
• /
• pp.181-185
• /
• 2001

The naturally occurring chemical indole-3-carbinol (13C), found in vegetables of the Brassica genus, is a promising anticancer agent that was shown previ- ously to induce a Gl cell cycle arrest of human breast cancer cell lines, independent of estrogen receptor signaling. The anticancer activity of 13C and the possible mechanisms of its action were explored in a human hepatocellular carcinoma cell line, HepG2. Treatment of HepG2 cells with 13C suppressed the growth of the cells. The growth sup- pression caused by 13C ($IC_{50}$/: 444$\mu$M) was found to be partially due to its ability to stop the cell cycle in HepG2 cells. Western blot analysis for the Gl phase artiest demonstrated that the expression-levels of cyclin-dependent kinase (Cdk4, Cdk6) and cyclic D were reduced strongly after treatment of Hep72 cells with 13C (4007M) for 24- 72 hrs. Furthermore, I3C selectively abolished the expression of Cdk6 in a dose- and time-dependent manner, and accordingly, inhibited the phosphorylation of retinoblastoma. Interestingly, after the HepG2 cells reached their max- imal growth arrest, the level of the p21, a well-known Cdk inhibitor, increased significantly. Therefore, it could be considered that the Gl arrest of HepG2 cells treated with 13C was due to the indirect inhibition of Cdk4/6 activities by p21 Western blot analysis for G2/M phase arrest of demonstrated the levels of Cdc2 and cyclin Bl werer reduced dramatically after the treatment of HepG2 cells with 13C ($40\mu$M) for 24-72 hrs. flow cytometry of propidium iodide-stained HepG2 cells revealed that 13C induces a Gl (53%,72hr incubation) and G2 (25%,24hr incubation) cell cycle arrest. Thus, our observations have uncovered a previously undefined antiproliferative pathway for r3C that implicates Cdk4/6 and Cdc2 as a target for cell cycle control in human HepG2 cells. However, the 13C-medi- ated cell cycle arrest and repression of Cdk4/6 production did not affect the apoptotic induction of HepG2 cell.

• Journal of Animal Science and Technology
• /
• v.50 no.5
• /
• pp.591-600
• /
• 2008

This study was conducted to investigate relationships among cow daily milk yield, calf body weight at birth and 3 month of age and calf preweaning daily gain. Cow daily milk yield(DMILK) of 90 days after postpartum measured by weigh-suckle-weight method, calf birth weight(BW), calf body weight at 3 month of age(WT3), and calf preweaning daily gain from birth to 3 month of age(PDG) were collected from June to November on 2002 and April to November on 2003. All traits studied were considered as cow traits and analysed by WOMBAT packages to obtain A-I REML(average information restricted maximum likelihood) estimates. Heritability estimate of daily milk yield uncorrected for cow-calf separation time(DMILK) was 0.39, which was not differ from 0.36 of heritability estimate corrected on the basis of 24 hour cow-calf separation time(CMILK). Heritability estimates for maternal genetic effects of BW, WT3 and PDG were respectively 0.28, 0.17 and 0.18. Genetic correlations between DMILK and maternal effect of BW, WT3 and PDG were respectively 0.59, 0.79 and 0.68. High genetic correlation coefficients of DMILK with WT3 and PDG indicate that selections for maternal breeding value for WT3 or PDG may be effective to enhance the cow’s milk production ability in Hanwoo.

• Journal of Intelligence and Information Systems
• /
• v.20 no.4
• /
• pp.1-23
• /
• 2014

Market forecasting aims to estimate the sales volume of a product or service that is sold to consumers for a specific selling period. From the perspective of the enterprise, accurate market forecasting assists in determining the timing of new product introduction, product design, and establishing production plans and marketing strategies that enable a more efficient decision-making process. Moreover, accurate market forecasting enables governments to efficiently establish a national budget organization. This study aims to generate a market growth curve for ICT (information and communication technology) goods using past time series data; categorize products showing similar growth patterns; understand markets in the industry; and forecast the future outlook of such products. This study suggests the useful and meaningful process (or methodology) to identify the market growth pattern with quantitative growth model and data mining algorithm. The study employs the following methodology. At the first stage, past time series data are collected based on the target products or services of categorized industry. The data, such as the volume of sales and domestic consumption for a specific product or service, are collected from the relevant government ministry, the National Statistical Office, and other relevant government organizations. For collected data that may not be analyzed due to the lack of past data and the alteration of code names, data pre-processing work should be performed. At the second stage of this process, an optimal model for market forecasting should be selected. This model can be varied on the basis of the characteristics of each categorized industry. As this study is focused on the ICT industry, which has more frequent new technology appearances resulting in changes of the market structure, Logistic model, Gompertz model, and Bass model are selected. A hybrid model that combines different models can also be considered. The hybrid model considered for use in this study analyzes the size of the market potential through the Logistic and Gompertz models, and then the figures are used for the Bass model. The third stage of this process is to evaluate which model most accurately explains the data. In order to do this, the parameter should be estimated on the basis of the collected past time series data to generate the models' predictive value and calculate the root-mean squared error (RMSE). The model that shows the lowest average RMSE value for every product type is considered as the best model. At the fourth stage of this process, based on the estimated parameter value generated by the best model, a market growth pattern map is constructed with self-organizing map algorithm. A self-organizing map is learning with market pattern parameters for all products or services as input data, and the products or services are organized into an $N{\times}N$ map. The number of clusters increase from 2 to M, depending on the characteristics of the nodes on the map. The clusters are divided into zones, and the clusters with the ability to provide the most meaningful explanation are selected. Based on the final selection of clusters, the boundaries between the nodes are selected and, ultimately, the market growth pattern map is completed. The last step is to determine the final characteristics of the clusters as well as the market growth curve. The average of the market growth pattern parameters in the clusters is taken to be a representative figure. Using this figure, a growth curve is drawn for each cluster, and their characteristics are analyzed. Also, taking into consideration the product types in each cluster, their characteristics can be qualitatively generated. We expect that the process and system that this paper suggests can be used as a tool for forecasting demand in the ICT and other industries.

• Korean Journal of Poultry Science
• /
• v.39 no.1
• /
• pp.63-70
• /
• 2012

This study was conducted to determine the possible use of Red Ginseng marc as stress inhibiter in thermal stress (temperature humidity index 86) and lipopolysaccharide (LPS) - exposed laying hens by investigating their effects on laying performance, blood biochemical parameters, immunoglobulin concentration and serum superoxide dismutase (SOD) like ability. A total of forty-five 52-wk-old laying hens (ISA Brown) were divided into 3 treatment groups with 5 replicates of 3 birds in each group. NC (negative control, no immune substances), PC (positive control, ${\beta}$-glucan 25 ppm) and RGM (Red Ginseng Marc 3%) were added in feed with respective substance. Egg production in RGM was significantly increased in comparison with NC groups for 8 weeks (P<0.05). On blood biochemical parameters, effects of ambient temperature is definite by showing significant difference in aspartate aminotransferase and others (P<0.05), but RGM both before and after thermal stimulation have no significant difference in comparison with other groups. And for 3 weeks after thermal stimulation, laying performance was also not significantly different among treatments. Immunoglobulin M content and SOD like activities after challenge with LPS were higher in the RGM and PC than NC (P<0.05). In conclusion, although ineffective as inhibiter in thermal stress, dietary supplementation of Red Ginseng marc improved SOD like activity and immune system by regulating immunoglobulin content in laying hens. These findings have laid the foundation for future studies of immunomodulation in laying hens fed Red Ginseng Marc and of evaluation of heat stress inhibitor.

• Research in Plant Disease
• /
• v.21 no.4
• /
• pp.280-289
• /
• 2015

Maize (Zea mays L.) is an economically important crop in worldwide. While the consumption of the maize is steadily increasing, the yield is decreasing due to continuous mono-cultivation and infection of soil-borne fungal pathogens such as Fusarium species. Recently, stalk rot disease in maize, caused by F. subglutinans and F. temperatum has been reported in Korea. In this study, we isolated bacterial isolates in rhizosphere soil of maize and subsequently tested for antagonistic activities against F. subglutinans and F. temperatum. A total of 1,357 bacterial strains were isolated from rhizosphere. Among them three bacterial isolates (GC02, GC07, GC08) were selected, based on antagonistic effects against Fusarium species. The isolates GC02 and GC07 were most efficient in inhibiting the mycelium growth of the pathogens. The three isolates GC02, GC07 and GC08 were identified as Bacillus methylotrophicus, B. amyloliquefaciens and B. thuringiensis using 16S rRNA sequence analysis, respectively. GC02 and GC07 bacterial suspensions were able to suppress over 80% conidial germination of the pathogens. GC02, GC07 and GC08 were capable of producing large quantities of protease enzymes, whereas the isolates GC07 and GC08 produced cellulase enzymes. The isolates GC02 and GC07 were more efficient in phosphate solubilization and siderophore production than GC08. Analysis of disease suppression revealed that GC07 was most effective in suppressing the disease development of stalk rot. It was also found that B. methylotrophicus GC02 and B. amyloliquefaciens GC07 have an ability to inhibit the growth of other plant pathogenic fungi. This study indicated B. methylotrophicus GC02 and B. amyloliquefaciens GC07 has potential for being used for the development of a biological control agent.

• Research in Plant Disease
• /
• v.18 no.3
• /
• pp.201-209
• /
• 2012

The multi-function of 18 Bacillus subtilis isolates collected from agricultural extension centers of local government and National Academy of Agricultural Science was investigated by measuring their antifungal activities against five plant pathogens, such as Rhizoctonia solani, Colletotrichum acutatum, Fusarium oxysporum, Magnaporthe oryzae and Phytophthora capsici, phosphorus solubilization ability, production of indole acetic acid (IAA) and siderophore, and nitrogen fixation. The B. subtilis isolates showed antifungal activity against several plant pathogens and nitrogen fixation activity, and produced siderophore and IAA. They could control pepper powdery mildew (Leveillula taurica), but there was no difference in control efficacy among the B. subtilis isolates. In fields, the control efficacy of B. subtilis R2-1 ($10^8$ cells/ml) was compared with two microbial fungicides, Q-pect and Topsid. In 2009, the control efficacy of B. subtilis R2-1 (37.7%) was lower than that of Topsid (47.6%), but higher than that of Q-pect (25.7%). In 2010, the control efficacy of B. subtilis R2-1 (83.3%) was higher than that of Topsid (67.9%). In order to elucidate mode of action of B. subtilis R2-1 for controlling pepper powdery mildew, spore germination rates of pepper powdery mildew pathogen collected on treated leaves was investigated when suspensions of B. subtilis R2-1 and two microbial fungicides (Q-pect and Topsid) were foliar-sprayed. They highly suppressed spore germination of the pathogen with inhibition values of 84.2% for B. subtilis R2-1, 97.9% for Q-pect and 94.7% for Topsid. Further study on the mass-culturing method and formulation is needed for development of a microbial fungicide.