• Korean Journal of Ecology and Environment
• /
• v.52 no.1
• /
• pp.9-12
• /
• 2019

The red-eared slider (Trachemys scripta elegans) is the one of the most popular pets, and the most commonly traded species in the world. It is designated as an ecosystem disturbance species that has been managed in South Korea. To date, no reports of natural or anthropogenic migration and spreading of T. s. elegans in South Korea are available. In the present study, we estimated the expected route and the movable path of one female T. s. elegans found in Namsan-myun, Gyeongsan-si, Gyeongsangbuk-do. Based on the movable path, the potential destination of the female turtle was estimated to be about 282 m and 468 m away. Therefore, the moving distance of the red-eared slider to the nearest water system will be at least 606 m and at most 792 m. Our results provide the first evidence about the natural migration and spreading of exotic turtles. This study can serve as a basis for the management and countermeasures against the introduced of T. s. elegans and other exotic species in South Korea.

• Journal of Korean Society on Water Environment
• /
• v.24 no.5
• /
• pp.523-532
• /
• 2008

A phase II site investigation and feasibility study was conducted at a military mortar shooting range near the demilitarized zone (Kyunggi, South Korea) to assess the extent of contaminants migration to the nearby Imjin river in which a flood control dam is under construction. The results showed that silty-clay soils around target areas were co-contaminated with heavy metals (Cd, Cu, and Pb) and explosives (HMX, RDX, and TNT). The total amount of contaminant was estimated to be 497.1 kg-RDX, 20.6 kg-HMX, 1.4 kg-TNT, 35.2 kg-Cd, 4,331 kg-Cu, and 5,115 kg-Pb, respectively. Both heavy metals and explosives were almost equally distributed on each soil particle size fraction. Neither subsurface soil samples nor ground water samples showed signs of contamination above the environmental criteria. The major migration route of contaminants was soil particles in surface run-off during rain at which a mass discharge rate of 30.0 mg-RDX/hour was observed.

• Korean Journal of Environmental Agriculture
• /
• v.33 no.4
• /
• pp.334-343
• /
• 2014

BACKGROUND: Shorebirds use a variety of wetlands as their stopover sites to replenish energy and nutrient reserves along the migration route. It is increasingly important to understand how birds use the remaining available habitats during migration period, because shorebird stopover sites are often altered and destroyed. Rice fields serve as a major inland stopover site for migrating shorebirds. However, the information on habitat use patterns of shorebirds in rice fields is very limited in Korea. Therefore, we studied the patterns of shorebird abundance and their habitat use in rice fields during spring migration period in western-central Korea. METHODS AND RESULTS: Surveys were conducted at interval of 2-3 days during the spring migration period of 2014 at rice fields of mid-western Korea. We recorded the location of the observed birds on the rice field map according to the local habitat type. The habitat types were divided by physical structure and cultivation methods. Fifteen shorebird species and 7,852 individuals were recorded during the survey period. The number of shorebird species and their abundance began to increase from the beginning of flooding in late-April, and reached a maximum in early-May. After rice transplantation, the number of shorebird species and their abundance dramatically declined. Shorebirds selectively used paddy and levee rather than road and ditch and most species used shallow depth field type. Plowed field types were less attractive to most species. CONCLUSION: Flooding rice fields were functioned as stopover sites for a variety of shorebird species during spring migration period. Furthermore, these results provide that the appropriate agricultural practices can be improving the habitat quality for shorebirds.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2018.05a
• /
• pp.419-421
• /
• 2018

Cloud vehicular networks are a promising paradigm to improve vehicular through distributing computation tasks between remote clouds and local vehicular terminals. Software-Defined Network(SDN) can bring advantages to Intelligent Transportation System(ITS) through its ability to provide flexibility and programmability through a logically centralized controlled cluster that has a full comprehension of view of the network. However, as the SDN paradigm is currently studied in vehicular ad hoc networks(VANETs), adapting it to work on cloud-based vehicular network requires some changes to address particular computation features such as task computation of applications of cloud-based vehicular networks. There has been initial work on briging SDN concepts to vehicular networks to reduce the latency by using the fog computing technology, but most of these studies do not directly tackle the issue of task computation. This paper proposes a Software-Defined Cloud-based vehicular Network called SDCVN framework. In this framework, we study the effectiveness of task computation of applications of cloud-based vehicular networks with vehicular cloud and roadside edge cloud. Considering the edge cloud service migration due to the vehicle mobility, we present an efficient roadside cloud based controller entity scheme where the tasks are adaptively computed through vehicular cloud mode or roadside computing predictive trajectory decision mode. Simulation results show that our proposal demonstrates a stable and low route setup time in case of installing the forwarding rules of the routing applications because the source node needs to contact the controller once to setup the route.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2018.05a
• /
• pp.238-240
• /
• 2018

Cloud vehicular networks are a promising paradigm to improve vehicular through distributing computation tasks between remote clouds and local vehicular terminals. Software-Defined Network(SDN) can bring advantages to Intelligent Transportation System(ITS) through its ability to provide flexibility and programmability through a logically centralized controlled cluster that has a full comprehension of view of the network. However, as the SDN paradigm is currently studied in vehicular ad hoc networks(VANETs), adapting it to work on cloud-based vehicular network requires some changes to address particular computation features such as task computation of applications of cloud-based vehicular networks. There has been initial work on briging SDN concepts to vehicular networks to reduce the latency by using the fog computing technology, but most of these studies do not directly tackle the issue of task computation. This paper proposes a Software-Defined Cloud-based vehicular Network called SDCVN framework. In this framework, we study the effectiveness of task computation of applications of cloud-based vehicular networks with vehicular cloud and roadside edge cloud. Considering the edge cloud service migration due to the vehicle mobility, we present an efficient roadside cloud based controller entity scheme where the tasks are adaptively computed through vehicular cloud mode or roadside computing predictive trajectory decision mode. Simulation results show that our proposal demonstrates a stable and low route setup time in case of installing the forwarding rules of the routing applications because the source node needs to contact the controller once to setup the route.

• Journal of Korean Society of Transportation
• /
• v.22 no.5
• /
• pp.47-57
• /
• 2004

This study introduces the areawide road safety improvement program, which was developed to overcome the weak points of conventional black spot improvement programs. The latter has been criticized in terms of that it can cause the problem of accident migration and that it prevents from identifying causes of road accident in the comprehensive scope. On the other hand, the areawide road safety improvement program can allow us to find the route or areas that have quite a number of road accidents with the common causes. Therefore, we can take countermeasures effectively in a different framework in this approach. This study explains in detail about the concept, procedures, and effects of areawide road safety improvement programs including the example. This study may contribute to bringing a new framework of road safety improvement program in Korea.

• Journal of Life Science
• /
• v.29 no.7
• /
• pp.769-773
• /
• 2019

In this study, the migration route and the absorption rate of calcium and magnesium in apple leaves were compared and analyzed using plant nutrients prepared by wet nano-grinding technology. The plant nutrients were sprayed onto the leaves to confirm the component content and the movement route of the nanoized calcium and magnesium. At 2, 4, and 8 weeks after the plant nutrient treatment, the apple leaves were divided into petiole, lamina, and side, and SEM and EDS were used to measure the calcium and magnesium contents. The calcium and magnesium contents of the petiole increased from the 4th week after plant nutrient application to 1,115% at the 8th week. The calcium and magnesium contents of the lamina decreased after spraying but increased after 4 weeks. The calcium and magnesium contents increased in the side of the leaves compared to the control, reaching 673% after 4 weeks. The calcium and magnesium contents increased with increasing duration in all plots when compared with the control unsprayed leaves, suggesting that the usually poorly soluble calcium and magnesium were transferred from the petioles to the lamina. The results of this study indicate that improved calcium and magnesium absorption could be obtained in crops other than apples using plant nutrients produced through wet nano-processing technology. This technology is also expected to be applicable to natural products and bioindustries.

• Journal of Environmental Impact Assessment
• /
• v.20 no.1
• /
• pp.13-24
• /
• 2011

This study was carried out to analyze ecological characteristics and select target species for effective restoration plans of wildlife corridors at Galmachi of Sungnam City. The actual vegetation in study area was physiognomically mixed with deciduous broad leaved forests dominated by oaks and artificially planted species. And it is a secondary forest formatted by sprout originated stand and being on early succession stage as a young stand. So study site was regarded as not suitable for the habitats for wildlife. The number of mammal species at study site was total 22 species, but most of these species were found as not so many in individual numbers. The individual number of hare was approximately 4 to 8, while the raccoon dog and water deer with 2 to 3 and 1 to 2, respectively. As such, it was estimated as a low population density due to discontinuation of ecosystem and the man-made impacts. In this study, raccoon dog and water deer were selected as the target species because of their migration patterns and ecological value in local ecosystem. It was suggested to establish a wildlife corridors of an over-bridge type at the peak area of Galmachi, known to be the mostly-used migratory route for 2 target species.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.44 no.3 s.357
• /
• pp.18-25
• /
• 2007

In sensor networks, sensor nodes have limited computational capacity, power and memory. Thus energy efficiency is one of the most important requirements. How to extend the lifetime of wireless sensor networks has been widely discussed in recent years. However, one of the most effective approaches to cope with power conservation, network scalability, and load balancing is clustering technique. The function of a cluster head is to collect and route messages of all the nodes within its cluster. Cluster heads must be changed periodically for low energy consumption and load distribution. In this paper, we propose an energy-aware cluster head selection algorithm and Distance Estimation-based distributed Clustering Algorithm (DECA) in wireless sensor networks, which exchanges cluster heads for less energy consumption by distance estimation. Our simulation result shows that DECA can improve the system lifetime of sensor networks up to three times compared to the conventional scheme.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.9
• /
• pp.2453-2458
• /
• 2010

Photochemical studies of N-[(trimethylsilyl)alkyl]saccharins were carried out to investigate their photochemical behavior. Depending on the nature of the substrate and the solvent system employed, reactions of these substances can take place by either SET-promoted silyl migration from carbon to either the amide carbonyl or sulfonyl oxygen or by a N-S homolysis route. The results of the current studies show that an azomethine ylide, arising from a SET-promoted silyl migration pathway, is generated in photoreactions of N-[(trimethylsilyl)methyl]saccharin and this intermediate reacts to give various photoproducts depending on the conditions employed. In addition, irradiation of N-[(trimethylsily)ethyl]saccharin produces an excited state that reacts through two pathways, the relative importance is governed by solvent polarity and protic nature. Finally, photoirradiation of N-[(trimethylsilyl)propyl]saccharin in a highly polar solvent system comprised of 35% aqueous MeOH gives rise to formation of a tricyclic pyrrolizidine and saccharin that generated via competitive SET-promoted silyl transfer and $\gamma$-hydrogen abstraction pathways.