• The Korean Journal of Financial Management
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• v.21 no.1
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• pp.183-204
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• 2004

This paper introduces an observable connection structure between stocks in Korean stock market and investigates the formation principles of the observed connection structure between stocks in economic views. Several recent studies have been attempting to explain that the connection structure between stocks is organized by Power-Law distribution, this implies that most stocks have a few links, but only a few stocks have very large number of links. Therefore, we want to investigate the reason about why the connection structure between stocks exhibited by Mantegna's approach is Power-Law distribution. As a result we found that the number of connection between stocks is determined by market factors and specific firm factors among many other factors. In addition, if a stock is more affected by common factors(market) than specific firm factors, the stock has large number of links with other stocks, otherwise more affected by specific firm factors, the stock has a few links.

• Korean Management Science Review
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• v.29 no.2
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• pp.53-64
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• 2012

This paper is about the investment strategy in stocks on Fundamental analysis. Financial data of stocks from January 2. 2001 through October 30. 2009 were utilized in order to suggest the investment strategies. Fundamental analysis was used in stocks-related strategy. The portfolios are composed of 3 criteria such as the buying criteria score, exchange cycle and selling conditions. The buying criteria score is determined assigned to each stock index according to the satisfaction condition of 15 parameters selected considering the grue's criteria. The stock buying alternatives has two options with buying stocks over 13 points and over 14 points of buying criteria score. The seven exchange cycles and three selling methods are considered. So total number of portfolios is 42($2{\times}7{\times}3=42$). The simulation has been executed about each 42 portfolios and we figured out with the simulation result that 83.33% of 35 portfolios are more profitable than average stock market profit(203.43%). The outcome of this research is summarized in two parts. First, it's the exchange strategy of portfolio. The result shows that value-oriented investment (long-term investment) strategy yields much higher than short-term investment strategies of stocks. Second, it's about the exchange cycle forming the portfolios. The result shows that the rate of return for the portfolio is the best when exchange cycle is 18 months.

• Journal of Sericultural and Entomological Science
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• v.37 no.2
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• pp.114-120
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• 1995

The effect of juvenile hormone analogue(JHA, Manina) on larval feeding duration, pupation ratio, cocoon weight, and cocoon shell weight in the present commercial parent and hybrid silkworm stocks were investigated. Topical applications of JHA on parent silkworm stocks were to prolong larval duration, but results of response on those stocks were not consistent. Especially the JHA on Jam 121, Jam 123 and Jam 138 did not play a role in larval duration, whereas that on Jam 114 was most effective in prolongation more than two days, compared with the controls. subsequent prolongation of feeding duration resulted in increase of cocoon weight and cocoon shell weight of most parent silkworm stocks, while Jam 114 showed decrease in cocoon weight and cocoon shell weight in spite of prolonged feeding duration of two days. Unlike the parent silkworm stocks, durations of feeding period in all hybrid silkworm stocks were prolonged about one day. Treatments of JHA on the hybrid stocks gave rise to increase of cocoon weight and cocoon shell weight, and especially were most effective in Sasung-jam, Eunbaek-jam and Samgwang-jam. Although treatments of JHA seemed to have no harmful effect on physiology of parent silkworm stocks as well as that of hybrid stocks, the JHA retarded pupation ratio of some parent silkworm stocks such as Jam 122, 131, 135 and 138 by about 10%.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10a
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• pp.55-62
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• 2002

Significant changes in the performance requirements of finished lubricants is having a pronounced impact on the quality and manufacturing approach for base stocks, the building block for these products. Separation processing is no longer capable of producing high yields of premium base stocks and is rapidly being replaced with hydroprocessing. Isoparaffins are the most desirable component because of their high Viscosity Index, low pour point and excellent stability. This paper will discuss industry trends and the drive towards higher quality base stocks. Manufacturing options are discussed and examples presented to demonstrate the performance of these premium base stocks.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1627-1633
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• 2004

Safety and punctuality in the subway are considered as critical factors. This system is composed of many factors like signals, rails, electrical power sources, rolling stocks. The effective inspection should be carried out at all the times for the safety and punctuality. Purpose of the rolling stocks maintenance is to offer the optimum condition of vehicles, and minimize the maintenance expenses. This paper suggests appropriate maintenance period of rolling stocks to enhance the utility efficiency in SMSC.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.388-397
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• 1998

This paper gives the way of analyzing internal noise of rolling stocks which is urgently required by civilians. Triangular beam method among ray tracing techniques is utilized to compute noise distribution of rolling stocks. Noise source and transmisstion loss of several sections from experimental work are included in this calculation. Ray tracing technique is found useful to compute big structures like rolling stocks.

• The Journal of Fisheries Business Administration
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• v.40 no.2
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• pp.71-103
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• 2009

This study is designed to propose the ways of the multilateral cooperation system for effective management of fisheries resources in the various overlapping zones established by bilateral fisheries agreements between Korea, China and Japan in North East Asia as semi-enclosed sea. It is necessary to build multilateral fisheries cooperation between Korea, China and Japan in North East Asia because conservation & management of transboundary fish stocks could not be guaranted effectively by the management of fisheries resources in the area where piled up the current-fishing-pattern zone, as white zone and the various grey zone as middle zone, and the interim measures zone of bilateral fisheries agreements between Korea, China and Japan are piled up. Fisheries management in Korea, China and Japan by the bilateral fisheries agreements in North East Asia is faced with difficulties manage fisheries resources. International relationship on fisheries is maintained by bilateral fisheries agreements based on UNCLOS. However fisheries resources are over-exploited and the recovery of the fisheries resources is very slow because proper conservation and management of transboundary fish stocks which article 63(1) of UNCLOS defines have not prepared yet. Thus close cooperation among the coastal States for a proper conservation and management of transboundary fish stocks is necessary. Since the transboundary fish migrate within the EEZs of two or more coastal States, there is a need to manage the fish stocks in the region between Korea, China and Japan through a multi-lateral mechanism at ccircumference area of the current-fishing-pattern zone as white zone. Coastal States must guarantee sustainable maintenance of transboundary fish stocks through the regional cooperation for a proper conservation & management because one coastal State alone could not guarantee conservation and management of fish stocks. Thus there is a need to build multilateral fisheries cooperation between Korea, China and Japan in North East Asia. There are many successful instances including the Barents' sea for a proper conservation & management of transboundary fish stocks. The Barents' sea is one of the best research object to study the regional cooperation for a conservation & management of transboundary fish stocks in North East Asia. In conclusion, it is necessary to build a multilateral fisheries cooperation system between Korea, China and Japan in North East Asia to conserve and manage transboundary fish stocks effectively. It seems desirable that the range of the area to conserve and manage fish stocks should may be any partial area in the current-fishing-pattern zone and interim measures zone between Korea and China, Jeju middle zone between Korea and Japan, interim measures zone of bilateral fisheries agreements between China and Japan.

• The Journal of the Korea Contents Association
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• v.19 no.10
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• pp.364-371
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• 2019

The World Health Organization (WHO) announced the 11th International Classification System (ICD-11), which classifies game addiction as a disease in 2018. Sin stocks are defined as the companies that have negative addictive properties and are taxed on social costs. If a game disorder is listed in the disease classification system in Korea, it is highly likely that Korean game companies may be considered as sin stocks that causes negative addictive properties and social costs such as the game addiction and the game addiction tax. This suggests that game companies could be newly included in the scope of sin stocks in Korea. In this study, we examine the effect of the inclusion of game companies in the scope of sin stocks on the job preferences of game companies. We found that there is a high level of opposition to the opinion of the listing sin stocks of game companies, and a high degree of addiction and gambling was suggested as the cause of the game companies being classified as sin stocks. We also found that firm value and job preference would be decrease if a game company was classified as sin stocks. The study is meaningful in that it suggests that game companies can be perceived negatively as sin stocks due to the disease code of game disorder, which has recently emerged as a social issue. Also, this study will contribute to the academia and market participants by reporting statistically the effect of the classification of sin stocks in game companies on job preferences for game companies.

• Journal of Ecology and Environment
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• v.43 no.1
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• pp.43-60
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• 2019

Background: Tropical montane forests played an important role in the provision of ecosystem services. The intense degradation and deforestation for the need of agricultural land expansion result in a significant decline of forest cover. However, the expansion of agricultural land did not completely destruct natural forests. There remain forests inaccessible for agricultural and grazing purpose. Studies on these forests remained scant, motivating to investigate biomass and soil carbon stocks. Data of biomass and soils were collected in 80 quadrats ($400m^2$) systematically in 5 forests. Biomass and disturbance gradients were determined using allometric equation and disturbance index, respectively. The regression modeling is employed to explore the spatial distribution of carbon stock along disturbance and environmental gradients. Correlation analysis is also employed to identify the relation between site factors and carbon stocks. Results: The result revealed that a total of 1655 individuals with a diameter of ${\geq}5cm$, representing 38 species, were measured in 5 forests. The mean aboveground biomass carbon stocks (AGB CS) and soil organic carbon (SOC) stocks at 5 forests were $191.6{\pm}19.7$ and $149.32{\pm}6.8Mg\;C\;ha^{-1}$, respectively. The AGB CS exhibited significant (P < 0.05) positive correlation with SOC and total nitrogen (TN) stocks, reflecting that biomass seems to be a general predictor of SOCs. AGB CS between highly and least-disturbed forests was significantly different (P < 0.05). This disturbance level equates to a decrease in AGB CS of 36.8% in the highly disturbed compared with the least-disturbed forest. In all forests, dominant species sequestrated more than 58% of carbon. The AGB CS in response to elevation and disturbance index and SOC stocks in response to soil pH attained unimodal pattern. The stand structures, such as canopy cover and basal area, had significant positive relation with AGB CS. Conclusions: Study results confirmed that carbon stocks of studied forests were comparable to carbon stocks of protected forests. The biotic, edaphic, topographic, and disturbance factors played a significant variation in carbon stocks of forests. Further study should be conducted to quantify carbon stocks of herbaceous, litter, and soil microbes to account the role of the whole forest ecosystem.

• Atmosphere
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• v.33 no.1
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• pp.61-72
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• 2023

Accurate estimation of forest carbon stocks is important in establishing greenhouse gas reduction plans. In this study, we estimate the spatial distribution of forest carbon stocks using machine learning techniques based on high-resolution remote sensing data and detailed field survey data. The high-resolution remote sensing data used in this study are Landsat indices (EVI, NDVI, NDII) for monitoring vegetation vitality and Shuttle Radar Topography Mission (SRTM) data for describing topography. We also used the forest growing stock data from the National Forest Inventory (NFI) for estimating forest biomass. Based on these data, we built a model based on machine learning methods and optimized for Korean forest types to calculate the forest carbon stocks per grid unit. With the newly developed estimation model, we created forest carbon stocks maps and estimated the forest carbon stocks in South Korea. As a result, forest carbon stock in South Korea was estimated to be 432,214,520 tC in 2020. Furthermore, we estimated the loss of forest carbon stocks due to the Donghae-Uljin forest fire in 2022 using the forest carbon stock map in this study. The surrounding forest destroyed around the fire area was estimated to be about 24,835 ha and the loss of forest carbon stocks was estimated to be 1,396,457 tC. Our model serves as a tool to estimate spatially distributed local forest carbon stocks and facilitates accounting of real-time changes in the carbon balance as well as managing the LULUCF part of greenhouse gas inventories.