• Proceedings of the Korean Society of Crop Science Conference
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• 1999.11a
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• pp.80-101
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• 1999

Self-sufficiency ratio of food crops in Korea is estimated under $20{\%}$ in 2010 because total food consumption including feed will be increased. but food grain production will be decreased. It is necessary to maintain the optimum level of food self-sufficiency rate to secure national food demand/supply balance and non-trade and multiple function of agriculture in Korea. It will be possible to produce more food grains having the acceptable quality if the appropriate policy and cropping techniques are developed and practised in future. Breeding for high yielding varieties should be the first target to raise the production potential of food crops . Number of varieties developed during last 30 years is counted as 353 in food crops. New varieties developed in 1990s showed the higher yield potential and the improved agronomic characteristics compared with 1970s and 1980s varieties. But number of varieties planted on the farmer's field over $5{\%}$ of national planting area is less than one third of total varieties developed Breeding efforts to maintain planting area of main food crops should be focussed on consumer's demand and farmer's need. They are the best quality variety in each field of crop utilization, the newly designed variety adapting to changes of natural, rural and cropping environment, and the higher yielding variety. It is also needed to develop new quality crop varieties for inducing more consumption of crop grain produced in Korea for direct food or processing. Development of barley varieties for animal feed. high income soybean varieties, high quality wheat variety. and super yielding rice and barley varieties are also needed to keep or maximize national food production potential. In order to establish the appropriate cropping technique for domestic food security, the strong and continuous interest and financial support on crop breeding are required, and the inter-disciplinary and inter-institutionary researches should be strengthened for successful crop breeding.

• Journal of Korean Society of Forest Science
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• v.98 no.5
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• pp.593-601
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• 2009

Forest disturbances including forest fire, insect pests and diseases, landslides, and forest conversion from 1976 to 2005 were investigated to trace the changes of major forest disturbance agents and their characteristics over time in accordance with changes in natural and social environment in South Korea. While the damaged area by insect pests and diseases continuously decreased for the past 30 years, damaged areas by forest fire and landslide were fluctuating through years. The interval of large forest fires has become shorter with increased tree volume. The precipitation between January and April were significantly correlated with large fire occurrences as Pearson's correlation coefficient -0.400 (P=0.029). The composition of major insect pests and diseases damaging Korean forests has been changed continuously, and become more diversified. While damages by pine caterpillar (Dendrolimus spectabilis) and pine needle gall midge (Thecodiplosis japonensis) decreased, damage by introduced pests has been more serious recently. The change of precipitation pattern that brought more localized heavy rain or powerful typhoon resulted in the recent increase in landslide areas. The major land uses to induce forest conversion have been changed, reflecting the changes in industrial structure in South Korea as agriculture and mining in 1970s, mining and golf ranges classified in pasture in 1980s, and road and housing construction in 1990s and 2000s. Changes in forest disturbance patterns in South Korea show that a country's industrial development is jointly working with global warming on forest stand dynamics. Altering energy structure and land use pattern induced by industrial development accumulates forest volume and reforms microenvironments on forest floor, interacting with climate change, inducing shorter interval of large forest fire and changes in major species composition of forest insect pests and diseases.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.59 no.4
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• pp.315-327
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• 2023

In the last five decades, there has been a consistent decline in the total catch of fisheries in the Korean jurisdiction since the peak in 1986. The decline in catch slowed and slightly rebounded in the 2000s, but changed back to a decline in the 2010s. As indicators that can identify changes in the marine ecosystem, trophic level (TL), biodiversity index (H'), and the ratio between pelagic fish and demersal fish (P/D) were analyzed by each local marine ecosystem. There were some different changes in each local marine ecosystem, but the mean TL and H' decreased and P/D increased in general in Korean waters. Demersal fish, which were dominant in the 1970s and 1980s, declined, and small pelagic fish and cephalopods have dominantly changed since the 1990s. However, these changes are not simple, and they are fluctuating in complex ways relating to each marine ecosystem and the timing. It is believed that changes in marine ecosystems in Korean waters are likely caused by a combination of fisheries and climate change. The ecosystem indicators reflected a change in the total catch, a sharp drop in catch of demersal fish, and increasing catch of pelagic fish since the mid-1980s.

• Clinical and Experimental Pediatrics
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• v.55 no.8
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• pp.280-285
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• 2012

Purpose: The authors analyzed the trend from the birth-related statistics of high birth weight infants (HBWIs) over 50 years in Korea from 1960 to 2010. Methods: We used 2 data sources, namely, the hospital units (1960's to 1990's) and Statistics Korea (1993 to 2010). The analyses include the incidence of HBWIs, birth weight distribution, sex ratio, and the relationship of HBWI to maternal age. Results: The hospital unit data indicated the incidence of HBWI as 3 to 7% in the 1960's and 1970's and 4 to 7% in the 1980's and 1990's. Data from Statistics Korea indicated the percentages of HBWIs among total live births decreased over the years: 6.7% (1993), 6.3% (1995), 5.1% (2000), 4.5% (2000), and 3.5% (2010). In HBWIs, the birth weight rages and percentage of incidence in infants' were 4.0 to 4.4 kg (90.3%), 4.5 to 4.9 kg (8.8%), 5.0 to 5.4 kg (0.8%), 5.5 to 5.9 kg (0.1%), and >6.0 kg (0.0%) in 2000 but were 92.2%, 7.2%, 0.6%, 0.0%, and 0.0% in 2009. The male to female ratio of HBWIs was 1.89 in 1993 and 1.84 in 2010. In 2010, the mother's age distribution correlated with low (4.9%), normal (91.0%), and high birth weights (3.6%): an increase in mother's age resulted in an increase in the frequency of low birth weight infants (LBWIs) and HBWIs. Conclusion: The incidence of HBWIs for the past 50 years has been dropping in Korea. The older the mother, the higher was the risk of a HBWI and LBWI. We hope that these findings would be utilized as basic data that will aid those managing HBWIs.

• Korean Journal of Social Welfare
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• v.57 no.3
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• pp.337-361
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• 2005

This study seeks the implications for the Korean family welfare policies after examining the characteristics of fertility rates and family welfare policies of advanced OECD countries, and comparatively analyzing the fertility rates among clusters of countries having similar family welfare policies. The fertility rates of most advanced OECD countries declined below the population replacement level in the 1970s, and continuously declined slowly after that period. But in the 1990s the fertility rate of some countries increased, on the other hand that of other countries declined. Such a difference of fertility rates suggests that there is some correlation between the fertility rate and the family welfare policy of each country. Advanced countries became concerned about the decline of fertility rate, established the government Population Issues Committee in order to deal with population problems, and increased family welfare supports. But the level and pattern(focusing on maternal employment supports or child-rearing supports) of each country's family welfare policies are differently developed according to its political ideology, cultural and historical background, and economic environments. A comparative assessment of the fertility rate among clusters of countries having similar family welfare policies demonstrates that the higher the level of family welfare supports is and the level of maternal employment supports in comparison with that of maternal child-rearing supports is, the higher of fertility rate is. And a comparative assessment of the fertility rate changes among clusters of countries also shows that the higher the level of family welfare supports is and the level of maternal employment supports in comparison with that of maternal child-rearing supports is, the higher the increase of fertility rate is or the lower the decrease of fertility rate is. The implications for the Korean family welfare policies are summarized as follows. First, it is necessary to establish the government Population Issues Committee which can study systematically fertility rates and population problems, and provide comprehensive population measures. Second, family welfare supports should be expanded through the establishment of family allowances, the prolongation of maternity leave and child-care leave and the upward readjustment of child-care leave benefits, and the extension of public child-care facilities. Third, maternal employment supports such as public child-care facilities and maternity leave should be given more weight than maternal child-rearing supports such as family allowance. Fourth, it is required to prepare social environments which can provide the youth with the hope that child-rearing is not difficult and gives them happiness.

• Journal of the Korean GEO-environmental Society
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• v.21 no.12
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• pp.29-34
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• 2020

Reinforced earth retaining walls were developed in France in the 1970s and began to be applied in earnest to Korea in the 1990s. And now, about 1,300 reinforced soil retaining walls support the embankment of highways and bridge connections. The reinforced earth retaining wall construction technology has evolved day by day, and in recent years the reinforced earth retaining wall itself has been developed and introduced as a demonstration. However, various damages are constantly occurring in the reinforced earth retaining walls constructed throughout the highway. The cause of this was analyzed as minor defects in the design, construction, and maintenance stages. The solution for this is a change in perception of the importance of each individual process, but this does not form overnight. In this study, 30 years have passed since the introduction of the reinforced soil retaining wall on the highway, the damage cases were analyzed and categorized that have occurred in the reinforced soil retaining wall so far, and attempted to present a confrontation. As a result, the damage occurring on the reinforced soil retaining wall was divided into 10 types, and the causes and countermeasures in the design, construction, and maintenance stages for each were derived.

• International Commerce and Information Review
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• v.13 no.3
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• pp.353-375
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• 2011

Export control was first triggered by international export control system at US led COCOM in 1949. Numerous international efforts such as NPT in 1969, ZC in 1970, NSG in 1978, AG in 1985, MTCR in 1987, Wassenaar Arrangement(WA) establishment in 1995 with 1990's the fall of the Berlin Wall, have been made since. The concept of export control has been changed from weaponry and parts export control to preventing or blocking weaponry, respective goods and relevant technology from the hand of troubled regions and non-state actors as terrorist groups; and the new concept is described as Nonproliferation Control. Extent of control items is not only limited to conventional weaponry, but also includes weapons of mass destruction(WMD) and even dual use items which can be used for production, development, usage or storage. Control items include all items defined by NSG, MTCR, AG, WA, and CMC-Opec. The 9.11 terror had a strong influence on international society. Effort to prevent WMD proliferation has now become the most important issue for international security. This study aims to suggest improvement points for nonproliferation law and its effective implementation, based on problem and limitation identification along with analysis of nonproliferation law and implementation examples by type. Furthermore for the purpose of national and global security, export control system on strategic items which are considered to be a key issue in South and North Korea relationship needs to be effectively managed. Recently, North Korea's missile and nuclear tests have been criticized globally; and the global society including respective countries as China and South Korea is striving to urge export control in line with the UN resolution.

• Korean Journal of Heritage: History & Science
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• v.53 no.3
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• pp.184-201
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• 2020

After the liberation of Korea from Japanese colonialism, archeology in South and North Korea took different paths. In particular, archeology in South and North Korea began to show great differences from the 1970s, when the former experienced rapid academic advancement following the evacuation of large-scale relics and the latter began to demonstrate a drastically political nature. North Korea declared 'Daedonggang Culture' in the 1990s, and South and North Korean archeology subsequently became so divorced that the two shared almost no common ideas. This kind of discrepancy is now particularly prominent with regard to the Bronze Age and Iron Age around "Gojoseon". Researchers of prehistoric archeology in South Korea have no choice but to keep referring to North Korean archeology. This is because North Korean resources are the main research subjects for identifying "the origin and descent of culture", which is still one of the most important research topics. However, people cast doubt on their reliability. Such a "two-fold viewpoint" demonstrates how those associated with South Korean archeology perceive their counterparts in North Korea. A large part of the visible "gap" between South and North Korea in terms of Bronze Age archeology comes from "political difference" that cannot be resolved by an increase in survey cases or academic debate. However, examining the trend in prehistoric archeology in North Korea is not aimed at criticizing the political nature of North Korean archeology. The goal is to investigate how the North Korean perspective on the Bronze Age differs from that in South Korea at present and to examine the potential problems in explaining "prehistoric culture in the Korean peninsula" and, furthermore, prehistoric culture in Northeast Asia, by including North Korean resources. This paper examines how Bronze Age-related research trends have evolved in North Korea to date and compares them with those seen in South Korean archeology during the same period.

• Journal of the Korean Geographical Society
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• v.43 no.5
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• pp.715-727
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• 2008

This study analyzed changes on the best condition of temperature and relative humidity for making artificial snows in the Yongpyong Ski Resort using data from Daegwallyeong. Depth of snowfall and snowfall days have decrease since 1990s. If the Yongpyong Ski Resort has only to depend on natural snows, it would be difficult to make and maintain ski slope. There are two times of snowmaking during ski seasons: one is the first snowmaking (October-November) for opening ski slopes and the other is the reinforcement of snowmaking (December-March) for maintaining snow quality during the seasons. Days having the best condition for the first snowmaking (daily minimum temperature below $-1^{\circ}C$ and daily average relative humidity 60 to 80 percent) decreased after 1970s. Days having the best condition for the reinforcement of snowmaking also decreased. While temperature changes are more evident than humidity changes for the first snowmaking, humidity changes are more obvious than change of temperature for the reinforcement of snowmaking. In the future climate projection by A1B scenarios, the length of ski seasons projected to decrease a 10 to 40 percent against the period of 1973-2008. The climate condition for the snowmaking projected to be poor, especially the due to increase of temperature.

• Journal of the Korean Geographical Society
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• v.45 no.4
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• pp.478-501
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• 2010

The purpose of this study is to understand spatial economic inequalities under the framework of the dynamics of economic spaces in relation to the four global megatrends: globalization, knowledge-based economy, information society, and the service world. The international inequalities in East Asia, as well as inter-regional inequalities within Japan, Korea, and Thailand were analyzed. The variables related to the four megatrends, as a whole, have clearly explained the variations in international inequalities in East Asia, as well as the inter-regional inequalities within a nation. The individual impacts of the variables on spatial inequalities are, however, significantly different depending on the spatial scale of analysis and national characteristics. Overall, there has been a convergence trend of international per capita GNI (Gross National Income) in East Asian nations, while both divergent and convergent trends are evident at the regional scale within a nation. Two global oil crises in the 1970s and the East Asian financial crisis in the late 1990s resulted in the discontinuity of the general convergence trend, and have led to the increase of international and inter-regional inequalities in economic activities. This suggests that although the effect of the global crisis differs in each country, in general, the economies of peripheral countries and regions are more vulnerable during a global economic crisis.