• Korean Journal of Microbiology
• /
• v.45 no.2
• /
• pp.119-125
• /
• 2009

To understand the ecological function of heterotrophic bacterial community in water column of large freshwater lakes in the permafrost zone, we investigated the structure and function of bacterial community in Lake Khuvsgul, Mongolia. Species composition of overall bacterial community was analyzed by denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene fragments, and bacteria that can be cultured at 10oC were isolated and characterized. Based on the depth profile of environmental parameters, thermocline and chemocline were recognized at the 5~10 m zone of the water column. The stratified DGGE profile indicated that the discontinuity of water properties might influence the structure of bacterial community: band profiles in the 0~5 m zone were diverse with large change by depth, but the profile was relatively stable at the $\geq$10 m zone, with predominance of the band identified as Acidovorax facilis. Bacterial cultures were screened for protease, cellulase, amylase and lipase activity, and 23 isolates were selected for high activity of the hydrolytic enzymes. The isolates were identified based on their 16S rRNA gene sequences. In the surface water (zero meter depth), Acidovorax defluvii and Sphingobacterium faecium with high cellulase activity were present. Flavobacterium succinicans, Mycoplana bullata and A. facilis were stably predominant isolates at 2 m, 5 m, and $\geq$10 m depths, respectively. F. succinicans isolates showed high protease activity while M. bullata isolates showed moderate levels of protease and celluase activity. A. facilis isolates showed either cellulase or lipase activity, exclusively to each other. According to the profile of growth rates of the isolates in the temperature range of $0\sim42^{\circ}C$, the surface-zone (0~5 m) isolates were facultative psychrophiles while isolates from $\geq$10 m depth were typical mesophiles. This stratification is believed to be due to stratified availability of organic materials to the bacterial decomposers. In the water column below the chemoline, the environment is extremely oligotrophic so that the trait of rapid growth in low temperature might not be demanded by deep-lake decomposers. The stratified distribution of community composition and decomposer activity in Lake Khuvsgul implies that ecological functions of bacterial community in lakes of cold region are sharply divided by water column stratification.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.11 no.4
• /
• pp.158-164
• /
• 2006

Yongdam Lake is the fifth largest artificial lake in Korea newly formed by the first impounding the Yongdam Multi-purpose Dam on December, 2002. Yongdam Lake, with her total water storage of 820 million M/T, is located at the roof-top region of the streams flowing into the just-constructed new Saemankeum Lake. Seasonal succession of phytoplakton in Yongdam Lake might affect cyanobacterial blooms in Saemankeum Lake by inoculating seasonal dominants. During 2002-2003 when the first impounding after the construction of Yongdam Multi-purpose Dam was still undergoing, summer cyanobacterial blooms by Anabaena, Microcystis, and Aphanizomenon were observed. Among these three, filamentous Anabaena is well known to have its species with $N_2-fixing$ ability and special cells such as heterocysts and akinetes as well as the vegetative cells. We established a clonal culture of Anabaena spiroides v. crasse (KNU-YD0310) from the live water samples collected at the bloom site of Yongdam Lake. The N- and P-nutrient requirement of the KNU-YD0310 was explored by the experimental cultivation of the laboratory strain. Ratio of heterocysts to vegetative cells increased as N-deficiency extended with its maximum at $N_2-fixing$ condition. The strain KNU-YD0310 exhibited considerable growth under N-limiting conditions while its growth was proportional to the initial phosphate-P concentration under P-deficient conditions. Under P-limiting conditions akinete density increased, which could be interpreted as an adaptation strategy to survive severe environment by transforming into resting stage. The above eco-physiological characteristics of Anabaena spiroides v. crassa might be useful as an ecological criterion in controlling cyanobacterial blooms at Shaemankeum Lake in near future.

• Korean Journal of Environment and Ecology
• /
• v.34 no.5
• /
• pp.413-424
• /
• 2020

Environmental policies and industry practices have recently seen a gradual paradigm shift from reactive management to proactive prevention of environmental impacts. Accordingly, preventive conservation policies are carried out to address the increasing value of protecting soils and soil functions as resources are limited. To propose a direction for future soil erosion research, we analyzed domestic and international research trends of soil erosion, based on journal papers retrieved from the Web of Science databases over the last decade, using VOSviewer for keyword co-occurrence analysis. The results showed that the number of publications on soil erosion per land area in Korea ranked high worldwide. In particular, studies on the soil erosion control were found to account for a more significant proportion than other countries. The active ongoing studies on soil erosion in Korea indicate that the country has recognized the severity of soil erosion resulting from climate, topography, and land use. However, the number of keywords found in the studies on the soil erosion control in Korea was relatively smaller than those found at the international level, indicating the need to diversify and expand the study subjects. In particular, studies on the soil erosion process and the related physical and chemical soil properties are necessary to find the fundamental solutions to soil erosion problems.

• Journal of the Korean association of regional geographers
• /
• v.1 no.1
• /
• pp.23-43
• /
• 1995

This paper is the first part of a research which looks into the regional development process and the quality of life of Youngnam area, and which suggests a prospect and tasks for the future development of the region. Youngnam region has grown rapidly on the basis of labor-intensive light industries and standardized Fordist lage-scale heavy industries through the industrialization and urbanization of South Korea from the 1960s; but recently it has shown a relatively downward trend. The recent economic stagnation of Youngnam region can be seen as a result of uneven regional development in the national scale, which has brought out the increasing subcontracting relation within the region, the geographically excessive concentration of firms, the lack of growth potentiality of high-tech industries, the weakness of producer service, and the shortage of financial activities for capital flows. In addition, construction of physical and social infrastructures and management of urban central functions could not meet properly the rapid economic and urban growth of the region. Because of these problematics inherent in the economy of Yougnam region, the occupational status of regional dwellers is more or less unstable, and the wage level of employee as a whole in Youngnam region is lower than those of Seoul, although the wage level of labourers in manufacturing is relatively high. Moreover, the quality of life of dwellers in the region has some difficulties in the use of resources and ecological environment as well as the unequal provision of means of living and welfare facilities, even though it has been improved materially.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.15 no.1
• /
• pp.31-44
• /
• 2020

Accelerators that invest in early startups, as well as nursery and overall management, have recently emerged as "key players" in the startup ecosystem. This can be proved by the case where the number of domestic accelerators registered in the Korean Ministry of SMEs and Startups has recently reached 208. Accelerators provide the necessary education for early-stage companies, including guidance for a certain period of time, and support startups in ways such as demo days to attract subsequent investment after the seed investment. There is not much research in academia about what factors impact on these accelerators when making investment decisions at the time of seed investment. In this study, we checked the meaning and function of the accelerator and tried to analyze what factors affect on accelerators when making a decision to invest in startups. The research method is based on a literature survey of previous studies on investment decision-making factors of venture capital and angel investors, and a lens model and judgment analysis method through empirical research targeting 43 accelerator investment decision-makers. Empirical analysis shows that accelerators have three of the key factors to consider when choosing the first startup to invest and educate; entrepreneurs' entrepreneurial traits, their product and service expertise and a potential return on success. This will provide an opportunity for early startups to gain strategic access to accelerators when they need money or need a structured educational program. Also, the results obtained through this research will be a kind of guideline for startups to attract accelerators' investment. The significance of this study is that discriminatory evidence was presented on the accelerator determinants of investment, and it would be highly suggestive to startups and related public institutions.

• Korean Journal of Environment and Ecology
• /
• v.1 no.1
• /
• pp.66-82
• /
• 1987

The user's composition of socia-economic characteristics in Bukhan Mountain National Park showed that male. twenties and students were 65.4 percent. 62.7 percent and 37.4 percent respectively by sex, age and occupation. In visiting purpose, the nature-oriented motive was 67.1 percent of the total. hut the picnic patterns as of neighbourhood park and the recreation patterns as of recreation ground were appeared simultaneously. In preferable place of visitors. the well-known mountain hut, camp sites and summits were prefered. The level of scenic satisfaction was 7.8 and comparatively high on considering the maximum level of 10.0. The level of total satisfaction. however, was no more than 6.3 owing to lack of accomodation facilities along trails, 63.4 percent of visitors were opposed to construction cable-car and visitors were anxious seriously about the nature deterioration. In Jeongnung valley, the number of users was the lagest, so that the maximum number of passangers a day attained to 20.000. The peak seasons of visiting were Spring and Fall, and the peak hours during a day was 10-11 hours A.M. and 3-5 hours P.M. Therefore partitioned spatial management in consideration of hiking pattern of nature park. picnic pattern as of neighbourhood park and recreation pattern as of recreation ground shall be necessary to solve the conflicts among functions.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.10
• /
• pp.361-371
• /
• 2020

Since the implementation of the sunset law in 2020, concerns have been raised over the reckless development of long-term non-executed urban parks. In this study, the FSDAF method and CASA-NPP model were used to evaluate the annual average NPP of long-term non-executed urban parks in Seoul. Based on this, the carbon loss and economic value were assessed under five development scenarios. The total NPP value of long-term non-executed urban parks, except for the greenbelt area in Seoul, was 4,892.18 t C. In the first scenario, the NPP and cost were 4,892.18 t C of vegetation carbon and 1.18 billion won, 2,548.55 t C of vegetation carbon and 615 million won in the second scenario, 238.94 t C of vegetation carbon and 58 million won in the third scenario, 848.38 t C of vegetation carbon and 205 million won in the fourth scenario, and 1,596.00 t C of vegetation carbon and 385 million won in the fifth scenario. These results are meaningful for evaluating vegetation carbon and economic value loss according to five different development scenarios. The results of this study are expected to be useful for the preparation of measures to minimize the impact of the development of long-term non-executed urban parks.

• Korean Journal of Environment and Ecology
• /
• v.29 no.4
• /
• pp.590-598
• /
• 2015

Despite various control methods for pine wilt disease, the disease has been increasing at an alarming rate every year in Korea. Still there is a lack of research on the problems of the current methods used to curb the disease. One main method to control pine wilt disease is fumigation for eliminating the larva of the pine sawyer beetle (Monochamus alternatus) which is known as the vector insect for pine wilt disease. We surveyed and analyzed the amount of destroyed uninfected trees in the fumigated area by studying 32 survey plots ($100m^2$) in Miryang city. The destroyed trees' crown area was estimated by induced regression between root collar area and crown area of the remaining trees (coniferous tree: $R^2=57.4$, deciduous broad-leaved tree: $R^2=63.8$). According to the analysis results, the infected trees (cut trees) were 18.7% and cut trees which were not infected were 35.5% of the total tree population of the study area on the basis of total crown area. In case of pine trees, 8.4% of uninfected trees were cut off but 62% of uninfected deciduous broad-leaved trees including Quercus spp. were affected and damaged during the fumigation process. Since these broad-leaved trees dominate the sub-canopy layer of the forest, this indiscriminate interruption of broad-leaved trees has the adverse effect of depriving the public benefits such as shadow, a cooler weather, controlling humidity, etc.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.14 no.1
• /
• pp.85-99
• /
• 2019

Startups need proper external supports to survive and build strong foundations for growth in their early stage. Accelerators help such startups by providing tangible and intangible resources. Accordingly, accelerators are creating a social environment that can effectively support the startups in the early stage, distinct from other institutions that fund or help the startups. However, the actual impact of accelerators on startups has not been yet fully scrutinized thoroughly, especially with the lack of theoretical lenses to comprehend accelerators. This paper aims to build a theoretical foundation to understand the role of accelerator, focusing on the network-based perspective. We briefly overview the concept of accelerator and the current status of the accelerator industry. Subsequently, focusing on the network that accelerators and startups create, this paper examines how the characteristics of the network relationships affect the growth and survival of the early-stage startups. Thus, by offering systematic analysis of the underlying mechanisms of the effects of the accelerators under network-based approach, this paper suggests a direction for the future empirical research on the topic of startup accelerator.

• Journal of Wetlands Research
• /
• v.24 no.1
• /
• pp.1-24
• /
• 2022

This study was conducted to perform efficient conservation and management by classifying the types of wetlands distributed in forests of Korea and assigning grades according to the evaluation system from 2015 until 2019. From 2005 to 2014, 1,264 sites derived from the first national forest wetland survey and 16 additional excavated sites were classified and also evaluated 455 out of a total of 1,280 forest wetlands. Forest wetlands are divided into four types: natural type, abandoned paddy field type, man-made type, and modified type, and by reclassifying them in detail, a total of 11 detailed wetland types could be distinguished. Based on this, evaluation was performed according to various items such as plants and ecology, hydrology and hydrology, humanities and society, and the degree of disturbance was graded. As a result, the forest wetland value was sorted at 30 A- grade sites, high-value B-grade 201 sites, moderate C-grade 184 sites, and low-value D-grade 40 sites. Forest Genetic Resource Reserve (FGRR) and other effective area -based conservation measures (OECMs) were designated for 231 sites that received a high grade of A or B, and a long-term monitoring system should be established to systematically conserve forest biodiversity hotspot. It is judged that wetlands need to be managed more effectively and at the national level.