Forest destruction is an inevitable result of the development processes. According to the environmental impact assessment, over 10% of the destroyed trees need to be recycled and transplanted to minimize the impact of forest destruction. However, the rate of successful transplantation is low, leading to a high rate of tree death. This is attributable to a lack of consideration for environmental factors when choosing a temporary site for transplantation and inadequate management. To monitor transplanted trees, a field survey is essential; however, the spatio-temporal aspect is limited. This study evaluated the applicability of remote sensing for the effective monitoring of transplanted trees. Vegetation indices based on satellite remote sensing were derived to detect time-series changes in the status of the transplanted trees at three temporary transplantation sites. The mortality rate and vitality of transplanted trees before and after the transplant have a similar tendency to the changes in the vegetation indicators. The findings of this study showed that vegetation indices increased after transplantation of trees and decreased as the death rate increased and vitality decreased over time. This study presents a method for assessing newly transplanted trees using satellite images. The approach of utilizing satellite photos and the vegetation index is expected to detect changes in trees that have been transplanted across the country and help to manage tree transplantation for the environmental impact assessment.
The gas sensor is essential to monitoring dangerous gases in our environment. Metal oxide (MO) gas sensors are primarily utilized for flammable, toxic and organic gases and O3 because of their high sensitivity, high response and high stability. Tungsten oxides (WO3) have versatile applications, particularly for gas sensor applications because of the wide bandgap and stability of WO3. Nanosize WO3 are synthesized using the hydrothermal method. Asprepared WO3 nanopowders are in the form of nanorods and nanorulers. The crystal structure is hexagonal tungsten bronze (MxWO3, x =< 0.33), characterized as a tunnel structure that accommodates alkali ions and the phase stabilizer. A gas detection test reveals that WO3 can detect acetone, butanol, ethanol, and gasoline. This is the first study to report this capability of WO3.
In this study, we synthesize silica-core gold-satellite nanoparticles (SGNPs) for the surface-enhanced Raman scattering (SERS) based sensing applications. They consist of gold satellite nanoparticles (AuNPs) fixed on the silica core nanoparticles, which sizes of AuNPs can be tunned by varying the amount of reactants (growth solution and reducing agent). Their surface plasmon resonance (SPR) properties were characterized by using UV-vis spectroscopy, showing that the growth of AuNPs on silica cores leads to the light absorption in the longer wavelength region. Furthermore, the size increase of AuNPs exhibited the dramatic change in SERS activity due to the formation of hot spots. The optimized SGNPs showing enhancement factor ~3.8x106 exhibited a detection limit of rhodamine 6G (R6G) as low as 10-8M. These findings suggest the importance of size control of SGNPs and their SPR properties to develop highly efficient SERS sensors.
The carbon-offset mechanism based on forest management has been recognized as a meaningful tool to sequestrate carbons already existing in the atmosphere. Thus, with an emphasis on the forest-originated carbon-offset mechanism, the accurate measurement of the carbon stock in forests has become important, as carbon credits should be issued proportionally with forest carbon stocks. Various remote sensing techniques have already been developed for measuring forest carbon stocks. Yet, despite the efficiency of remote sensing techniques, the final accuracy of their carbon stock estimations is disputable. Therefore, minimizing the uncertainty embedded in the application of remote sensing techniques is important to prevent questions over the carbon stock evaluation for issuing carbon credits. Accordingly, this study reviews the overall procedures of carbon stock evaluation-related remote sensing techniques and identifies the problematic technical issues when measuring the carbon stock. The procedures are sub-divided into four stages: the characteristics of the remote sensing sensor, data preparation, data analysis, and evaluation. Depending on the choice of technique, there are many disputable issues in each stage, resulting in quite different results for the final carbon stock evaluation. Thus, the establishment of detailed standards for each stageis urgently needed. From a policy-making perspective, the top priority should be given to establishinga standard sampling technique and enhancing the statistical analysis tools.
A remote sensing pheromone trap called IT pheromone trap (Korean patent: 10-0982563) was applied to monitor overwintering population changes of the oriental fruit moth, Grapholita molesta, for three successive years in apple orchards. Males of the overwintering populations were attracted during April and May. However, the occurrence peak was delayed and extended to early June in 2010, at which the average spring temperature was significantly lower than the previous years. These overwintering populations could be monitored by the remote-sensing pheromone trap. When the remote-sensing pheromone traps were deployed to apple orchards of different provinces in Korea in 2010, the maximal overwintering populations of G. molesta were monitored at May in all areas. However, the population sizes monitored were significantly different among different localities. This study suggests a practical application of IT pheromone trap to monitor G. molesta in field conditions.
연안 김 양식장의 효과적 관리를 위해서는 실제 시설량의 조사가 필요하며, 인공위성을 이용한 방법이 가장 효과적이다. 본 연구에서는 10m의 해상도를 갖고 있는 SPOT-5 다중분광영상을 사용하였으며, 김 양식장의 자동탐지알고리듬의 개발을 위하여 경 기도 화성시 제부도 남방해역에 대한 2005년도 영상을 사용하였다. 김 양식장을 추출하기 위하여 우선 3밴드 영상의 분광특성을 이용 한 밴드차(Band difference) 영상을 작성하여, 두 가지 방법(형태학적 처리기법 및 Canny 에지 탐지기법)으로 처리를 한 후, 두 결과를 합성하여 라벨링함으로써 탐지율을 극대화하였다. 마지막으로 2005년 우리나라 연안의 김 양식장에 대한 인공위성 조사 결과, 실제 시 설량은 676,749 책(柵)으로, 면허시설량 572,745 책보다 다소 많은 것으로 나타났다. 양식장 시설 현황 조사 결과는, 정부에서 전체 생산 량을 조절할 수 있게 하며, 양식업자가 좋은 수확을 달성하는데 도움이 될 수 있을 것이다.
공간 해상도 1m 이하의 고해상도 원격 탐사 영상의 민간 활용이 활발해 짐에 따라, 이를 위한 전문 분야 별 영상 분석 방법의 개발 요구가 증가하고 있다. 다양한 영상분석 기법 중에, 주변 화소들간의 공간 분포 관계에 의해 특성이 결정되는 텍스처 영상의 분석은 이러한 목적을 위한 유용한 영상 분석 방법 중 하나이다. 이 연구에서는 원시 영상으로부터 GLCM 알고리즘에 의해 생성된 텍스처 영상에 대해서 방향 인자, 마스킹 커널의 크기, 변수의 종류에 따른 결과를 비교, 분석한 뒤 각각의 결과 영상의 지형공간 특성 분석의 적용성에 대하여 알아보았다. 또한 원시 영상과 텍스처 영상에서 특성 정보를 포함하는 템플레이트를 설정하고 이를 기준으로 반복적인 패턴을 자동으로 검색하는 템플레이트 정합 프로그램을 구현하여 이를 원시 영상과 텍스처 영상에 적용하였고, 처리 결과에 기초하여 향후 적용 가능성을 검토하였다. 이 연구의 결과는 일정한 패턴으로 나타나는 지구과학적인 지형 특성이나 고해상도 위성영상 정보를 이용한 인공 지형지물의 파악 및 분석에 효과적으로 적용될 수 있을 것으로 예상된다.