57 research outputs found
Environmental Communication on Social Media: Environmental Non-Governmental Organizations (NGOs) and The Public. A Comparison between South Korea and Norway
Along with the emphasis on environmental communication, this thesis examines how environmental groups and the public communicate through social media in Norway and South Korea. Environmental communication plays a key role in navigating how we understand the imminent climate change and environmental issues, and achieve a transition to a sustainable future. However, environmental communication is a complex process because it involves various stakeholders and their own interests. Thus, setting appropriate environmental communication is a task that conveys information and encourages various stakeholders to take relevant actions to solve the problem. Specifically, environmental NGOs have been dedicated to serving as intermediaries between the public and other groups including scientists and politicians by bridging each other, who is to be engaged in environmental issues. Meanwhile, the rise of social media use has dramatically transformed the landscape of this environmental communication by fostering abundant networks across different spheres, both environmental groups and the public. Consequently, social media tools are currently used to disseminate environmental advocacy by environmental NGOs (Non-governmental Organizations), as well as to learn about the issues of individuals. Therefore, this thesis presents the interaction between environmental NGOs and public individuals using social media and compares Norwegian and Korean cases. This thesis aims to detect environmental communication gaps among all those distinct spheres, including cultural differences, and provide empirical details capturing valuable implications based on the linked findings.
Accordingly, this thesis is organized as a case study based on in-depth interviews using qualitative research methods. The interviews were conducted with selected environmental NGOs and individuals from Norway and Korea. The NGOs and individual participants were investigated for how NGOs disseminate their agenda using social media, and how individuals perceive environmental information of NGOs and become motivated to take action, respectively. In addition, Agenda-Setting theory and the Theory of Planned Behavior are mainly used to analyze and discuss the findings of results, linking this study to established hypotheses. The discussion focuses on connecting respective findings across the spheres investigated.
The results of this thesis generally confirm the principles of environmental communication, but also identify some gaps in investigated spheres across the levels. The findings show gaps between the communication strategies of NGOs and public perception, individual attitude-behavior gaps, and disparities between Norwegian and Korean groups. These differences encompass framing and perceiving the environmental issue salience, message tones, targeted scale of mitigation efforts, implementation of pro-environmental behaviors, and relationships with relevant stakeholders. This thesis portrays various intersections in the current environmental communication ecosystem and sheds light on the relationship between cultural context and environmental communication
Accurate and Efficient Computations of the Greeks for Options Near Expiry Using the Black-Scholes Equations
We investigate the accurate computations for the Greeks using the numerical solutions of the Black-Scholes partial differential equation. In particular, we study the behaviors of the Greeks close to the maturity time and in the neighborhood around the strike price. The Black-Scholes equation is discretized using a nonuniform finite difference method. We propose a new adaptive time-stepping algorithm based on local truncation error. As a test problem for our numerical method, we consider a European cash-or-nothing call option. To show the effect of the adaptive stepping strategy, we calculate option price and its Greeks with various tolerances. Several numerical results confirm that the proposed method is fast, accurate, and practical in computing option price and the Greeks
Efficient 3D Volume Reconstruction from a Point Cloud Using a Phase-Field Method
We propose an explicit hybrid numerical method for the efficient 3D volume reconstruction from unorganized point clouds using a phase-field method. The proposed three-dimensional volume reconstruction algorithm is based on the 3D binary image segmentation method. First, we define a narrow band domain embedding the unorganized point cloud and an edge indicating function. Second, we define a good initial phase-field function which speeds up the computation significantly. Third, we use a recently developed explicit hybrid numerical method for solving the three-dimensional image segmentation model to obtain efficient volume reconstruction from point cloud data. In order to demonstrate the practical applicability of the proposed method, we perform various numerical experiments
Prognostic Implication of Longitudinal Changes of Left Ventricular Global Strain After Chemotherapy in Cardiac Light Chain Amyloidosis
AimCardiac involvement is the main prognostic determinant in AL amyloidosis. We sought to determine the prognostic significance of longitudinal change of left ventricular (LV) global longitudinal strain (GLS) in cardiac light chain (AL) amyloidosis patients undergoing chemotherapy.Methods and ResultWe retrospectively investigated 117 cardiac AL amyloidosis patients who underwent chemotherapy from 2005 to 2019. All patients underwent comprehensive 2D conventional transthoracic echocardiography at baseline and after completion of first-line chemotherapy. Speckle tracking analysis of images was performed offline. Absolute value of LV GLS was expressed as [LV GLS] and change of [LV GLS] after chemotherapy was expressed as Δ [LV GLS]. Clinical outcomes including cardiac response and all-cause mortality were analyzed.Baseline clinical and echocardiographic parameters were similar in patients with and without CR. Δ [LV GLS] significantly differed between the CR and non-CR groups (0.4 ± 2.8% in the CR group vs. −0.6 ± 2.5% in the non-CR group, P-value = 0.046). Δ [LV GLS] showed satisfactory predictive performance for all-cause mortality (cut-off value = 0.8%, AUC 0.643, 95% CI [0.537–0.748]). Adding Δ [LV GLS] to the Mayo stage + pre-chemotherapy [LV GLS] model showed incremental prognostic value (C-index: 0.637 vs. 0.708; Relative Integrated Discrimination Index 0.07, P-value = 0.003; Net Reclassification Improvement 0.54, P-value < 0.001). Δ [LV GLS] showed good correlation with cardiac response (AUC 0.820, 95% CI [0.737–0.904]).ConclusionIn cardiac amyloidosis patients who underwent chemotherapy, longitudinal change of [LV GLS] after chemotherapy showed significant association with overall survival as well as cardiac response
Basic Principles and Practical Applications of the Cahn–Hilliard Equation
The celebrated Cahn–Hilliard (CH) equation was proposed to model the process of phase separation in binary alloys by Cahn and Hilliard. Since then the equation has been extended to a variety of chemical, physical, biological, and other engineering fields such as spinodal decomposition, diblock copolymer, image inpainting, multiphase fluid flows, microstructures with elastic inhomogeneity, tumor growth simulation, and topology optimization. Therefore, it is important to understand the basic mechanism of the CH equation in each modeling type. In this paper, we review the applications of the CH equation and describe the basic mechanism of each modeling type with helpful references and computational simulation results
Algal Boom Characteristics of Yeongsan River Based on Weir and Estuary Dam Operating Conditions Using EFDC-NIER Model
A number of hydraulic structures have been installed along the Yeongsan River, including an estuary dam and two weirs (Seungchon and Juksan). While these structures aid in regional water security and use and reduce flooding, they reduce water flow in the summer, thereby frequently causing algal blooms. This study simulated algal bloom and water quality characteristics of sections of the Yeongsan River in South Korea under different weir and estuary dam operating conditions using the Environmental Fluid Dynamics Code—National Institute of Environment Research (EFDC-NIER) model. Results showed that when the management levels of the Juksan Weir and estuary dam were maintained, simulated water levels were EL. 3.7 m in the weir section and EL. −1.2 m (below average water level of the Yellow Sea) in the dam section. When both the weir and dam were open, the water levels varied with the tide; in contrast, when the Juksan Weir alone was open, the water level was between EL. −1.2 and −0.9 m, in line with the management level of the estuary dam. Opening the weir alone reduced algal blooms by 72–84% in the weir region, and opening the estuary dam alone reduced the algal blooms by 83% in the dam region. This improvement was attributed to the reduced water retention time and dilution due to seawater inflows
Microphase separation patterns in diblock copolymers on curved surfaces using a nonlocal Cahn-Hilliard equation
We investigate microphase separation patterns on curved surfaces in three-dimensional space by numerically solving a nonlocal Cahn-Hilliard equation for diblock copolymers. In our model, a curved surface is implicitly represented as the zero level set of a signed distance function. We employ a discrete narrow band grid that neighbors the curved surface. Using the closest point method, we apply a pseudo-Neumann boundary at the boundary of the computational domain. The boundary treatment allows us to replace the Laplace-Beltrami operator by the standard Laplacian operator. In particular, we can apply standard finite difference schemes in order to approximate the nonlocal Cahn-Hilliard equation in the discrete narrow band domain. We employ a type of unconditionally stable scheme, which was introduced by Eyre, and use the Jacobi iterative to solve the resulting implicit discrete system of equations. In addition, we use the minimum number of grid points for the discrete narrow band domain. Therefore, the algorithm is simple and fast. Numerous computational experiments are provided to study microphase separation patterns for diblock copolymers on curved surfaces in three-dimensional space
A Crank–Nicolson scheme for the Landau–Lifshitz equation without damping
AbstractAn accurate and efficient numerical approach, based on a finite difference method with Crank–Nicolson time stepping, is proposed for the Landau–Lifshitz equation without damping. The phenomenological Landau–Lifshitz equation describes the dynamics of ferromagnetism. The Crank–Nicolson method is very popular in the numerical schemes for parabolic equations since it is second-order accurate in time. Although widely used, the method does not always produce accurate results when it is applied to the Landau–Lifshitz equation. The objective of this article is to enumerate the problems and then to propose an accurate and robust numerical solution algorithm. A discrete scheme and a numerical solution algorithm for the Landau–Lifshitz equation are described. A nonlinear multigrid method is used for handling the nonlinearities of the resulting discrete system of equations at each time step. We show numerically that the proposed scheme has a second-order convergence in space and time
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