• Journal of Internet Computing and Services
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• v.15 no.2
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• pp.9-18
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• 2014

The sensors attached on/in a person are moved since human body frequency changes their activity, therefore in wireless body area networks, nodal mobility and non-line-of-sight condition will impact on performance of networks such as energy efficiency and reliable communication. We then proposed schemes which study on forwarding decisions against frequent change of topology and channel conditions to increase reliable connections and improve energy efficiency. In this work, we control the size of packets, forwarding rate based on ratio of input links and output links at each node. We also robust the network topology by extending the peer to peer IEEE 802.15.4-based. The adaptive topology from chain-based to grid-based can optimal our schemes. The simulation shows that these approaches are not only extending network lifetime to 48.2 percent but also increase around 6.08 percent the packet delivery ratio. The "hot spots" problem is also resolved with this approach.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.4
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• pp.164-174
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• 2015

In a real scenario, radiometric change has frequently occurred in the stereo image acquisition process using multiple cameras with geometric characteristics or moving a single camera because it has different camera parameters and illumination change. Conventional stereo matching algorithms have a difficulty in finding correct corresponding points because it is assumed that corresponding pixels have similar color values. In this paper, we present a new method based on the local descriptor reflecting intensity, gradient and texture information. Furthermore, an adaptive weight for local descriptor based on the entropy is applied to estimate correct corresponding points under radiometric variation. The proposed method is tested on Middlebury datasets with radiometric changes, and compared with state-of-the-art algorithms. Experimental result shows that the proposed scheme outperforms other comparison algorithms around 5% less matching error on average.

• Journal of Digital Convergence
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• v.17 no.10
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• pp.251-258
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• 2019

In the future, various products are created in various fields using artificial intelligence. In this age, it is a very important problem to know the operation principle of artificial intelligence learning method and to use it correctly. This paper introduces artificial intelligence learning methods that have been known so far. Learning of artificial intelligence is based on the fixed point iteration method of mathematics. The GD(Gradient Descent) method, which adjusts the convergence speed based on the fixed point iteration method, the Momentum method to summate the amount of gradient, and finally, the Adam method that mixed these methods. This paper describes the advantages and disadvantages of each method. In particularly, the Adam method having adaptivity controls learning ability of machine learning. And we analyze how these methods affect digital signals. The changes in the learning process of digital signals are the basis of accurate application and accurate judgment in the future work and research using artificial intelligence.

• Journal of the Korea Society of Computer and Information
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• v.25 no.4
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• pp.55-61
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• 2020

In this paper, we present a novel approach to efficiently control the location of NPC(Non-playable characters) in the interactive virtual world such as game, virtual reality. To control the NPC's movement path, we first calculate the main trajectory based on the user's path, and then move the NPC based on the weight map. Our method constructs automatically a navigation mesh that provides new paths for NPC by referencing the user trajectories. Our method enables adaptive changes to the virtual world over time and provides user-preferred path weights for smartagent path planning. We have tested the usefulness of our algorithm with several example scenarios from interactive worlds such as video games, virtual reality. In practice, our framework can be applied easily to any type of navigation in an interactive world.

• Journal of Climate Change Research
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• v.8 no.2
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• pp.99-108
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• 2017

This study aims to analyze the features of adaptation governance of local governments by applying a multi-level governance framework, and to draw policy implications. We analyzed changes in governance of 17 metropolitan cities/provinces, and 33 municipalities in terms of horizontal and vertical cooperation in the process of developing 'The Climate Change Adaptation Action Plan' and its implementation stage. The result shows that the plan contributed to the higher level of vertical cooperation between the central and the local governments to a certain extent, however, during the implementation stage, the level of the partnership decreased due to the absence of governance mechanism. These trends were statistically significant at the level of municipalities. The role of Korea Adaptation Center for Climate Change (KACCC) was also diminished after establishing the plan. The horizontal partnership level among the relevant departments of the local governments showed no significant change as the level was low even in the planning stage. Though Public-Private Partnership (PPP) has increased a bit, it was statistically significant only in the municipalities. Moreover, there was no governance mechanism for PPP or it did not work properly. Based on the results above, it is recommended that the effectiveness of the plans should be increased and support for climate change partnerships or forums at a local level that promotes adaptive capacity is needed. The role of metropolitan cities and provinces should be strengthened through building a multi-level partnership structure. Governance institutionalizing for monitoring and evaluation is also needed.

• Journal of Digital Convergence
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• v.16 no.11
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• pp.465-470
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• 2018

This study investigated how layouts can be arranged to improve the user experience in response to changes in the size of responsive webs in a multi - device environment. The layout elements of the responsive web are largely divided into a header, a main concept image, a main content, a sub-content, and a footer. As the screen becomes smaller, the use of drawers and the menu of the scrolling menus rather than the vertical menus will help improve the user experience. The main concept image should be consistent and not lose readability through the use of system fonts. The main content and the sub content should be prevented from being long in the vertical scroll, and the card UI, the table list and the grid list could be alternatively presented for this purpose. Another problem with vertical scrolling is that the placement of user-selectable menus, such as more or new content corrections, is helpful in improving the user experience.

• Korean Journal of Child Education & Care
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• v.19 no.3
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• pp.183-197
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• 2019

Objective: The purpose of this study was to examine the effect of a group program using theraplay on 2-year-olds' prosocial behavior. The changes of prosocial behavior in the process of program were also examined. Methods: Subjects were 12 infants who attended a child care center in W city. Subjects were attached to the experimental or control group. The experimental group participated in 11 group theraplay sessions twice a week. The adaptive social behavior inventory (Hogan et al., 1992) was used for pre and post tests. Wilcoxon rank-sum test was performed to verify the effectiveness of a group theraplay program. Every sessions was video-taped and recorded verbatim. The verbatim were analyzed using the Padgett (2001)'s qualitative data analysis method. Results: Infants who assigned to the experimental group demonstrated significant improvement in prosocial behavior. Their expressive behavior and compliant behavior gradually increased over the sessions. Conclusion/Implications: The present study showed that the use of group program utilizing theraplay was an effective strategy for improving prosocial behavior of 2-year-old infants.

• Journal of Soil and Groundwater Environment
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• v.26 no.5
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• pp.60-76
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• 2021

The concept of resilience seems applicable for sustainable groundwater management. The resilience is broadly defined as the ability of a system to resist changes by external forces (EFs), and has been used for disaster management and climate change adaptation, including the groundwater resilience to climate change in countries where groundwater is a major water resource, whereas not yet in the geological society of South Korea. The resilience is qualitatively assessed using the absorptive, adaptive, and restorative capacity representing the internal robustness, self-organization, and external recovery resources, respectively, while quantitatively using the system impact (SI) and recovery effort (RE). When the groundwater is considered a complicated system where physicochemical, biological, and geological components interact, the groundwater resilience can be defined as the ability of groundwater to maintain the targeted quality and quantity at any EFs. For the quantitative assessment, however, the resilience should be specified to an EF and measurable parameters should be available for SI and RE. This study focused on groundwater resilience to two EFs in urban areas, i.e., pollution due to land use change and groundwater withdrawal for underground structures. The resilience to each EF was assessed using qualitative components, while measurements for SI and RE were discussed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.1
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• pp.29-37
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• 2021

It is important to introduce a local adaptive water supply system for upper mountainous regions, which provide a margin of water supply. This can be done through the process of securing a water source, planning for optimal use, and combining it with a water source that can be linked. In particular, in a mountainous region located at the uppermost part of the watershed, an approach should be found to utilize the groundwater discharge supplied through valley water and lateral discharge. This study sought to improve the water supply system using sand dams in drought-prone areas in Chuncheon, in Gangwon Province. Our approach involved virtually installing a sand storage tank under the existing water source to perform modeling in consideration of the current water intake and calculating the amount of water that can be taken from the sand dam. When the sand dam was applied at a size four times larger than the existing water source, it was found that the groundwater drainage increased significantly with changes in water surface slope and hydraulic conductivity.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.3
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• pp.929-946
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• 2022

Free viewpoint video (FVV) service is an immersive media service that allows a user to watch it from a desired location or viewpoint. It is composed of various forms according to the direction of the viewpoint of the provided video, and includes zoom in/out in the service. As consumers' demand for active watching is increasing, the importance of FVV services is expected to grow gradually. However, additional considerations are needed to seamlessly stream FVV service. FVV includes a plurality of videos, video changes may occur frequently due to movement of the viewpoint. Frequent occurrence of video switching or re-request another video can cause service delay and it also can lower user's quality of service (QoS). In this case, we assumed that if a video showing an object that the user wants to watch is selected and provided, it is highly likely to meet the needs of the viewer. In particular, it is important to provide an object-oriented FVV service when zooming in. When video zooming in in the usual way, it cannot be guaranteed to zoom in around the object. Zoom function does not consider about video viewing. It only considers the viewing screen size and it crop the video view as fixed screen location. To solve this problem, we propose a zoom in/out method of object-centered dynamic adaptive streaming of FVV in this paper. Through the method proposed in this paper, users can enjoy the optimal video service because they are provided with the desired object-based video.