• The KIPS Transactions:PartC
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• v.15C no.1
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• pp.51-60
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• 2008

Micro-mobility protocols have been developed to reduce the control message overhead due to movements of mobile nodes. With the spread of mobile devices, services using mobile nodes are increasing and multicast services are becoming more important in providing multimedia services. In this paper we propose a new multicast protocol suitable for micro-mobility environments. The proposed protocol is designed to maintain optimal multicast routing paths and continue to provide multicast services without disruption in spite of frequent handoffs due to movements of mobile nodes. We used simulation to evaluate the proposed protocol, compared its performance with existing multicast protocols for mobile environments including bi-directional tunneling, remote subscription, and MMA, and observed that the proposed protocol exhibited better performance in terms of transmission success ratio and overhead on the network.

• Physical Therapy Rehabilitation Science
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• v.7 no.2
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• pp.83-87
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• 2018

Objective: The purpose of this study was to investigate the relationship between heart rate (HR), self-awareness of exercise intensity (rating of perceived exertion, RPE), and 5-meter walk test (5MWT) of persons affected by stroke during backward walking according to the preferred stride frequency (PSF), PSF+3 and PSF+6 conditions. Design: Cross-sectional study. Methods: A total of 11 persons with stroke (9 males, 2 females) participated voluntarily. All patients underwent backward walking under the PSF, PSF+3, and PSF+6 conditions in underwater and ground environments, and each condition was performed for 5 minutes. The HR, RPE, and walking speeds were measured during walking, and the measured values from underwater and ground environments were compared. Results: The HR and RPE in the ground environment were significantly increased (p<0.05), and although the 5MWT showed an increase in speed, it was not significant. The HR and RPE in the underwater environment were also significantly increased (p<0.05), however, although the 5MWT results was increased, it was not significant. The HR and RPE were significantly increased in the PSF+6 condition (p<0.05). Conclusions: The results of this study showed that backward gait training underwater can provide an appropriate exercise intensity for stroke survivors and suggests that exercises performed in an underwater environment is more effective compared to the ground environment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.8
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• pp.2849-2864
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• 2021

The emerging of cloud data sharing can create great values, especially in multi-cloud environments. However, "data island" between different cloud service providers (CSPs) has drawn trust problem in data sharing, causing contradictions with the increasing sharing need of cloud data users. And how to ensure the data value for both data owner and data user before sharing, is another challenge limiting massive data sharing in the multi-cloud environments. To solve the problems above, we propose a Uniform Encoding and Parsing Framework (UEPF) with blockchain to support trustworthy and valuable data sharing. We design namespace-based unique identifier pair to support data description corresponding with data in multi-cloud, and build a blockchain-based data encoding protocol to manage the metadata with identifier pair in the blockchain ledger. To share data in multi-cloud, we build a data parsing protocol with smart contract to query and get the sharing cloud data efficiently. We also build identifier updating protocol to satisfy the dynamicity of data, and data check protocol to ensure the validity of data. Theoretical analysis and experiment results show that UEPF is pretty efficient.

• Journal of Information Processing Systems
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• v.14 no.6
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• pp.1480-1493
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• 2018

Recently, computational intelligence has received a lot of attention from researchers due to its potential applications to artificial intelligence. In computer science, computational intelligence refers to a machine's ability to learn how to compete various tasks, such as making observations or carrying out experiments. We adopted a computational intelligence solution to monitoring residual resources in cloud computing environments. The proposed residual resource monitoring scheme periodically monitors the cloud-based host machines, so that the post migration performance of a virtual machine is as consistent with the pre-migration performance as possible. To this end, we use a novel similarity measure to find the best target host to migrate a virtual machine to. The design of the proposed residual resource monitoring scheme helps maintain the quality of service and service level agreement during the migration. We carried out a number of experimental evaluations to demonstrate the effectiveness of the proposed residual resource monitoring scheme. Our results show that the proposed scheme intelligently measures the similarities between virtual machines in cloud computing environments without causing performance degradation, whilst preserving the quality of service and service level agreement.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.3
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• pp.41-48
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• 2019

The purpose of this study is to investigate the environmental factors relating to children's outdoor play and to assess how the residential neighborhood is suitable for play in the perception of parents. Based on a citywide survey of 500 parents of elementary school students in grades 1-4 in Seoul, this empirical study shows that children's outdoor play environments in residential neighborhoods of Seoul have been observed to be overall unsuitable for play activity. Three physical environmental factors (spatial availability, neighborhood attractiveness, and street difficulties) and three social environmental factors (fear of crime, social interactions, and psychological comfort) are related to children's play activity. Five factors, with the exception of the psychological comfort factor, impact the suitability of children's outdoor play environment. Specifically, it is the physical environment, rather than the social environment, that was deemed unsuitable in spite of its impacts. These findings help us understand the current conditions of neighborhood play environments associated with children's play activity. It is necessary to improve parents' perceptions of the play environment and children's play activities by improving the physical environment.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.2
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• pp.11-22
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• 2019

The purpose of this study is to explore changing attitudes towards old urban environments, represented in the comprehensive plans of Seoul, from the first 1966 plan through the most recent one of 2014. The results of analyzing all 6 Seoul urban comprehensive plans are as follows. The contents for considerations and actual planning actions for old urban environments were presented from the third comprehensive plan of 1990. The term 'historical heritage' was first applied in the urban park planning of the 1996 plan. In the 4th comprehensive plan of 1997, it began to regard historical landscapes as 'precious heritages' to make plans for using historical heritages in parts of landscape, education, and tourism. The scope of 'historical heritage' in the comprehensive plans has been expanded. This tendency continued to expand in the 5th plan of 2006, and again in the 6th plan of 2014. At the same time, in pursuing the identity of Seoul, 'historical heritage' in old urban environment came to be materialized further as planning objects.

• Architectural research
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• v.22 no.4
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• pp.155-162
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• 2020

Numerous scholars have explored the modeling, control, and optimization of energy systems in buildings, offering new insights about technology and environments that can advance industry innovation. Eye trackers deliver objective eye-gaze data about visual and attentional processes. Due to its flexibility, accuracy, and efficiency in research, eye tracking has a control scheme that makes measuring rapid eye movement in three-dimensional space possible (e.g., virtual reality, augmented reality). Because eye movement is an effective modality for digital interaction with a virtual environment, tracking how users scan a visual field and fix on various digital objects can help designers optimize building environments and materials. Although several scholars have conducted Virtual Reality studies in three-dimensional space, scholars have not agreed on a consistent way to analyze eye tracking data. We conducted eye tracking experiments using objects in three-dimensional space to find an objective way to process quantitative visual data. By applying a 12 × 12 grid framework for eye tracking analysis, we investigated how people gazed at objects in a virtual space wearing a headmounted display. The findings provide an empirical base for a standardized protocol for analyzing eye tracking data in the context of virtual environments.

• Educational Technology International
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• v.15 no.2
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• pp.49-69
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• 2014

The purpose of this study was to investigate the effect of co-regulated learning on the improvement of self-regulated learning skills in collaborative learning environments. One group pretest-posttest design was used in this study. The subjects were 49 undergraduate students who enrolled in 'Educational Evaluation' course. To facilitate students' co-regulated learning activities, group worksheets were developed. Students performed collaborative tasks in group by using the group worksheets over the 6 weeks. The results showed that the difference between means of the pretest and posttest was no statistically significant. It indicates that co-regulated learning activities did not have a significant effect on the improvement of self-regulated learning skills in collaborative learning environments. However, the results of additional analysis revealed that the difference between means of the pretest and posttest in case of 19 students with low self-regulated learning level was statistically significant. On the other hand, there was no statistically significant difference between means of the pretest and posttest in case of 19 students with high self-regulated learning level. It is interpreted that co-regulated learning activities positively affected the improvement of self-regulated learning skills of students with low self-regulated learning level.

• Journal of Sensor Science and Technology
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• v.33 no.3
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• pp.173-178
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• 2024

Development of pressure sensors for harsh environments with high pressure, humidity, and temperature is essential for many applications in the aerospace, marine, and automobile industries. However, existing materials such as polymers, adhesives, and semiconductors are not suitable for these conditions and require materials that are less sensitive to the external environment. This study proposed a pressure sensor that could withstand harsh environments and had high durability and precision. The sensor comprised a piezoresistor pattern and an insulating film directly formed on a stainless-steel membrane. To achieve the highest sensitivity, a pattern design method was proposed that considered the stress distribution in a circular membrane using finite element analysis. The manufacturing process involved depositing and etching a dielectric insulating film and metal piezoresistive material, resulting in a device with high linearity and slight hysteresis in the range of a maximum of 40 atm. The simplicity and effectiveness of this sensor render it a promising candidate for various applications in extreme environments.

• Korean Institute of Interior Design Journal
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• no.36
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• pp.84-92
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• 2003

Schools should be a safe and comfortable environment for learning and studying. However, school facilities are usually used by many students during restricted time. These conditions such as many people, restricted time and space mold a chain of school accidents. In Korea, the school accidents are increasing annually and many students experience 'big or small incidents' and are exposed to 'potential accidents'. In this study, I investigated the present situation of the elementary schools' accidents in In-Cheon area, and analyzed the various characteristics of them. The accidents in elementary school have tendencies of occuring frequently in higher grade and boy students relatively. As analyzed in the place of accident, classrooms have a set of factors of accident, on the other hand, corridor and staircase show single distinct cause of safety problem. And also, the major portion of accidents is associated with the door in restroom and entrance space. In order to reduce the severity and frequency of school accidents, there should be needed multilateral and interdisciplinary approach. To achieve the safe school environments, this study focused on establishing a foundation of practical directions in designing elementary schools.