위성영상 융합과 의사결정 나무를 이용한 홍수 침범지역 지도화

학위논문 (석사)-- 서울대학교 대학원 : 농업생명과학대학 생태조경·지역시스템공학부, 2018. 2. Dong Kun Lee.The mapping of spatial inundation patterns during flood events is important for environmental management and disaster monitoring. Satellite images provide important data sources for monitoring flood disasters. However, the trade-off between spatial and temporal resolutions of current satellite sensors limits their uses in flooding studies. This study applied data fusion models, the flexible spatiotemporal method, in generating synthetic flooding images with improved temporal and spatial resolution for flood mapping. This paper performs a detailed comparison of flood maps derived from for number of post-disaster prediction based on images acquired after the flooding, selected flood events in 2016 Tumen river in China. The result shows that the Landsat-like images generated can be successfully applied in flood mapping. From simulated Tumen river flood mapping during 29 August to 3 September,2016, can know when inundation occurs, this result map flood inundation region will full in map. Meanwhile, test the maximum inundation region and severely submerged spots and flood event occur and stop date during the event. The study suggests great potential of FSDAF in flooding research. Blending multi-sources images could also support other disaster studies that require remotely sensed data with both high spatial and temporal resolution.Chapter 1. Introduction 1 1.1. Study Background 1 1.2. Purpose of Research 3 Chapter 2. Literature Review 4 2.1. Image fusion method 4 2.1.1 Weighted function based 4 2.1.2 Unmixing based 5 2.1.3 Dictionary-pair learning based 6 2.1.4 Flexible Spatiotemporal Data Fusion (FSDAF) 7 2.2 Flood mapping 9 2.2.1 Pixel based classification 9 2.2.2 Object-based classification 10 2.2.3 Decision Tree 12 Chapter 3. Materials and Methods 14 3.1. Study Area 14 3.2 Material and Methods 15 3.2.1 Satellite Images and Data Processing 15 3.2.1.1 Landsat-8 Operational Land Imager (OLI) 17 3.2.1.2 Terra/Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) MCD43A4, Collection 18 3.2.2 Predicting flooding images through FSDAF and accuracy assessment 19 3.2.3 Flood mapping and accuracy assessment 23 3.2.4 Tumen river flood inundation simulation 28 Chapter 4. Result and Discussions 30 4.1. Comparison of predicted image and original Landsat image land cover type change 30 4.1.1 Test with satellite image in heterogeneous Landscape 30 4.1.2 Predicted surface reflectance on flood date 32 4.2 Flood inundation mapping 38 4.3 Tumen river flood event simulation 42 Chapter 5 Conclusions 44 Bibliography 48 Abstract (Korean) 56Maste

Employee Integrity and Corporate External Information Quality

Prior studies find dishonest top executives are associated with lower quality financial reporting. We focus on the role of rank-and-file employees in shaping financial data quality in that these employees are the sources of internal information transfer. Using a novel dataset that contains information on registrants using the Ashley Madison website to find extra-marital affair partners, we construct a firm-level employee integrity measure and assess the association between employee integrity and firm’s information quality. We find that low integrity of rank-and-file employees is associated with lower earnings quality and less accurate management forecasts, and we mitigate the potential endogeneity problem by estimating 2SLS regressions with instrument variables exogenous to firms’ information quality choices. Further analyses show that the negative relation between employee integrity and information quality is attenuated by higher managerial ability, and is robust to alternative employee integrity measures

Two-Component Signal Transduction Systems: A Major Strategy for Connecting Input Stimuli to Biofilm Formation

Biofilms are multicellular communities of microbes that are encased within an extracellular matrix. Environmental factors induce bacteria to form biofilm. Bacteria have several regulatory mechanisms in response to environmental changes, and the two-component signal transduction system (TCS) is a major strategy in connecting changes in input signals to changes in cellular physiological output. The TCS employs multiple mechanisms such as cross-regulation, to integrate and coordinate various input stimuli to control biofilm formation. In this mini-review, we demonstrate the roles of TCS on biofilm formation, illustrating these input signals and modulation modes, which may be utilized by future investigations in elucidating the regulatory signals and underlying the mechanisms of biofilm formation

Magnet bioreporter device for ecological toxicity assessment on heavy metal contamination of coal cinder sites

A novel magnet bioreporter device was developed in this research for soil toxicity assessment, via magnetic nanoparticles functionalized whole-cell bioreporters. The whole-cell bioreporter ADPWH-recA kept response capability to DNA damage after magnetic nanoparticles (MNPs) functionalization, and could be harvested from soil samples by permanent magnet to reduce the soil particle disturbance. Compared to conventional treatments applying bioreporter directly in soil-water mixture (SW-M treatment) or supernatant (SW-S treatment), MNPs functionalized bioreporter via the magnet device (MFB) treatment achieved high sensitivity to evaluate the toxicity and bioavailability of chromium contamination in soils from 10 mg/kg to 5000 mg/kg soil dry weight. The MNPs functionalized bioreporter also achieved high reproducibility with pH value from 5.0 to 9.0, salinity from 0% to 3% and temperature from 20 °C to 37 °C. A case study was carried out on the ecological toxicity assessment of heavy metal contamination at the coal cinder site via the magnet bioreporter device. The heavy metal toxicity declined with the increasing distance to the coal cinder point, and a significant accumulation of heavy metal toxicity was observed along the vertical distribution. No direct link was found between the pollution load index (PLI) and heavy metal toxicity, and the results suggested the bioreporter test monitored the toxicity of heavy metals in soils and was an important approach for ecological risk assessment. Magnet bioreporter device also offered the high throughput biological measurement and was feasible for in situ monitoring

Aging Resistance of Silica Fume/Styrene-Butadiene-Styrene Composite-Modified Asphalt

The influences of silica fume content and aging on the rheological properties of silica fume/styrene-butadiene-styrene composite-modified asphalts were investigated via rolling thin-film oven test simulations. The asphalts rheological properties before and after aging were measured using three-major-indices, dynamic shear rheology, and bending beam rheometer tests. Fourier transform infrared spectroscopy was used to examine the changes in the functional groups of the asphalt. The silica fume did not chemically react with the modified asphalt, and its original structure was maintained. The aging resistance improved significantly after adding the silica fume. At 6% silica fume content, the relaxation of the asphalt was the highest, indicating that the asphalt had the best low-temperature crack resistance at this mixing proportion. Furthermore, the carbonyl index value of this sample exhibited the smallest increment among all of the samples, and this asphalt sample had the strongest short-term aging resistance. Thus, the optimum silica fume content in the composite-modified asphalt was determined to be 6%. This information may be used to fabricate an asphalt mixture that can improve the service life and aging resistance of pavements

High spatiotemporal-resolution mapping for a seasonal erosion flooding inundation using time-series Landsat and MODIS images

Abstract Seasonal erosion flooding events present a significant challenge for effective disaster monitoring and land degradation studies. This research addresses this challenge by harnessing the combined capabilities of time-series Landsat and MODIS images to achieve high spatiotemporal-resolution mapping of flooding during such events. The study underscores the critical importance of precise flood monitoring for disaster mitigation and informed land management. To overcome the limitations posed by the trade-off between spatial and temporal resolution in current satellite sensors, we emplyedand theflexible spatiotemporal data fusion (FSDAF) methods to produce synthetic flood images with enhanced spatiotemporal resolutions for mapping by using MODIS and Landsat data from August 29 to September 3, 2016. A comparison was made between flood maps from several post-disaster forecasts based on ground-obtained time-series images of the Tumen River flood in China. According to the FSDAF approach, the input Landsat image of March 25, 2016, and the fused results had a root mean square error (RMSE) of 0.0301, average difference of 0.001, r of 0.941, and structure similarity indexof 0.939, indicating that temporal variation data had been effectively incorporated into a forecast on August 16, 2016. Results also indicated that the FSDAF forecast values are lower than those from the actual Landsat image. The results of the study also showed that the generated images could be effectively used for flood mapping. By using our newly developed simulation model, we were able to produce a comprehensive map of the inundated areas during the event from August 29 to September 3, 2016. This shows that FSDAF holds great potential for flood prediction and study and has the potential to benefit further disaster-related land degradation by combining multi-source images to provide high temporal and spatial resolution remote sensing information

Intervention mechanism of healthcare service goods based on social welfare maximization in China.

In this paper, we aim to establish a mathematical model to design a maximizing social welfare intervention mechanism of healthcare service goods in China. The intervention mechanism is helpful to facilitate the adoption of the healthcare service goods. We consider a research problem that regulates the supply chain system for healthcare service goods by an intervention mechanism, and two intervention strategies composed of demand-growth strategy and subsidy strategy are used to the combination of intervention mechanism. Then this paper presents a new method based on fuzzy set and bilevel programming to design the intervention mechanism. To demonstrate the effectiveness of the proposed model, we conduct a case study for Wudang personalized health package and verify our model by the specific result analysis, the result indicates that our joint intervention mechanism is helpful to achieve the target and increase social welfare

Connecting Metabolic Pathways: Sigma Factors in Streptomyces spp.

The gram-positive filamentous bacterium Streptomyces is one of the largest resources for bioactive metabolites, particularly antibiotics. Antibiotic production and other metabolic processes are tightly regulated at the transcriptional level. Sigma (σ) factors are components of bacterial RNA polymerases that determine promoter specificity. In Streptomyces, σ factors also play essential roles in signal transduction and in regulatory networks, thereby assisting in their survival in complex environments. However, our current understanding of σ factors in Streptomyces is still limited. In this mini-review, we demonstrate the roles of Streptomyces σ factors, illustrating that these serve as linkers of different metabolic pathways. Further investigations on σ factors may improve our knowledge of Streptomyces physiology and benefit exploitation of Streptomyces resources

Research on the Structural Features and Influential Factors of the Spatial Network of China’s Regional Ecological Efficiency Spillover

A regional coordinated development strategy is an important measure that is often used to implement sustainable development in China. However, many obstacles greatly limit the realization of regional ecological coordinated sustainable development. In this paper, ecological efficiency is utilized as an important indicator of sustainable development, and the network analysis method is used to explore the spatial correlation relationship of regional ecological coordinated sustainable development. This paper calculates the ecological efficiency of each region using the Window slacks-based measure (Window-SBM) model, formulates the spatial network of regional ecological efficiency spillover through the vector auto-regressive (VAR) Granger causality model, and analyzes the spatial spillover relationship and influencing factors of regional ecological efficiency by using the social network analysis method. It is found that the spillover network of ecological efficiency in each region presents a typical core-edge structure. In addition, there is an obvious hierarchical structure among blocks with different directions and functions. Industrial structure, economic development, and geographical proximity have a positive impact on the spatial spillover of regional ecological efficiency, while environmental regulation has a negative impact. Finally, relevant policy suggestions are put forward

Recent advances and perspectives in efforts to reduce the production and application cost of microbial flocculants

Abstract Microbial flocculants are macromolecular substances produced by microorganisms. Due to its non-toxic, harmless, and biodegradable advantages, microbial flocculants have been widely used in various industrial fields, such as wastewater treatment, microalgae harvest, activated sludge dewatering, heavy metal ion adsorption, and nanoparticle synthesis, especially in the post-treatment process of fermentation with high safety requirement. However, compared with the traditional inorganic flocculants and organic polymeric flocculants, the high production cost is the main bottleneck that restricts the large-scale production and application of microbial flocculants. To reduce the production cost of microbial flocculant, a series of efforts have been carried out and some exciting research progresses have been achieved. This paper summarized the research advances in the last decade, including the screening of high-yield strains and the construction of genetically engineered strains, search of cheap alternative medium, the extraction and preservation methods, microbial flocculants production as an incidental product of other biological processes, combined use of traditional flocculant and microbial flocculant, and the production of microbial flocculant promoted by inducer. Moreover, this paper prospects the future research directions to further reduce the production cost of microbial flocculants, thereby promoting the industrial production and large-scale application of microbial flocculants