• International Journal of Internet, Broadcasting and Communication
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• v.11 no.2
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• pp.43-49
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• 2019

Nowadays, one-person media broadcasting has become popular, and with the progress of this popularity, multimedia techniques which can support such broadcasting are also becoming more and more advanced. One of the most emerging multimedia technique used in this field is the virtual reality technology which sets the one-person media broadcasting environment as a virtual reality environment. However, as such an environment requires instruments of high cost, it is not easy for normal individuals to constitute such environments. Therefore, in this paper we propose how to construct virtual reality-like panoramas with a multiple of smartphones. For this purpose, we designed a special rig which can hold firmly 8 smartphone cameras which have overlapping view of the environment such that panorama stitching becomes possible. To reduce the computation cost, we precomputed the homography matrices, and used 1-D pointer structures to store the computed coordinate values.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.3
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• pp.1611-1625
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• 2019

The emergence of new technologies and devices brings a new environment in the field of cyber security. It is not easy to predict possible security threats about new environment every time without special criteria. In other words, most malicious codes often reuse malicious code that has occurred in the past, such as bypassing detection from anti-virus or including additional functions. Therefore, we are predicting the security threats that can arise in a new environment based on the history of repeated malicious code. In this paper, we classify and define not only the internal information obtained from malicious code analysis but also the features that occur during infection and attack. We propose a method to predict and manage security threats in new environment by continuously managing and extending.

• Korean Journal of Metals and Materials
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• v.50 no.12
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• pp.867-871
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• 2012

The microstructure and texture of TiN coatings on a Ni-based super-alloy were characterized by the automated version of electron backscatter diffraction (EBSD), EBSD techniques were used to investigate the very fine TiN grain shape and crystal orientation. This study confirmed that EBSD techniques provide a very useful tool for characterization of coating materials. The TiN grains had a special texture, a {001}-fiber texture in the coating layer. It was also found that, in severe environments, the coating performance of equiaxial and randomly oriented TiN is superior to that with columnar structures.

• IEMEK Journal of Embedded Systems and Applications
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• v.15 no.6
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• pp.307-316
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• 2020

Machine learning model data is highly affected by performance. preprocessing is needed to enable analysis of various types of data, such as letters, numbers, and special characters. This paper proposes a development environment that aims to process categorical and continuous data according to the type of missing values in stage 1, implementing the function of selecting the best performing algorithm in stage 2 and automating the process of checking model performance in stage 3. Using this model, machine learning models can be created without prior knowledge of data preprocessing.

• International journal of advanced smart convergence
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• v.11 no.2
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• pp.1-6
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• 2022

With the emergence of the new era of the 4th industrial revolution, compute-bound workloads with large memory footprint like big data processing increase dramatically. Even in such compute-bound workloads, however, we observe bulky I/Os while loading big data from storage to memory. Although file I/O cache plays a role of accelerating the performance of storage I/O, we found out that the cache hit rate in such environments is not improved even though we increase the file I/O cache capacity because of some special I/O references generated by compute-bound workloads. To cope with this situation, we propose a new file I/O cache management policy that improves the cache hit rate for compute-bound workloads significantly. Trace-driven simulations by replaying file I/O reference logs of compute-bound workloads show that the proposed cache management policy improves the cache hit rate compared to the well-acknowledged CLOCK algorithm by a large margin.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.50-51
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• 2020

Recently, various maintenance materials and construction methods have been developed to secure the sustainable performance of structures. However, waterproofing of underground structures where groundwater infiltration is present is very difficult. In particular, the location of underground structures such as subways is very deep, and it is difficult to apply waterproof materials and construction methods in the case of structures accompanied by vibration. Therefore, we intend to study materials and methods for waterproofing leakage resistance in special environments such as underground structures.

• Educational Technology International
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• v.7 no.1
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• pp.39-57
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• 2006

Supporting individual or group learners through designing effective learning environment has been major concern for instructional technologists. In CSCL environment, the effectiveness of learning depends not only on the design of the learning incidences but also on that of psychological environment because in CSCL the learners encounter virtually a new environment deviate from the ordinary physical world. CSCL is one of the most demanding environment for learners and thus it requires a highly refined learner support mechanisms. The purpose of the research was to devise conceptual tools for supporting learners in CSCL environment. Especially, the researchers tried to develop special kinds of scaffolding that directly support the collaborative practice in the social and psychological dimension of the learner. Body of literature on scaffolding has been reviewed and effective CSCL environments were observed and analyzed. As a result of the study, the research proposes a new type of scaffolding, named as "collaboration scaffolding" as a conceptual tool for supporting learners in CSCL environment. Also the research suggests three subtypes of scaffolds as the most typical collaboration scaffolding; emotional scaffolds, facilitative scaffolds, and exploratory scaffolds.

• The Journal of Korea Robotics Society
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• v.19 no.3
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• pp.229-235
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• 2024

This research focuses on reducers, vital components in service robots, with a special emphasis on friction reducers designed for use in environments where interaction with humans is essential. For service robots to effectively perform advanced tasks, it is crucial to have reducers that offer high precision, high reduction ratios, and strong resistance to impacts. To meet these requirements, our study introduces a new design methodology and proposes a friction reducer featuring a multi-layer ball array structure. Compared to traditional gearbox-based reducers, the friction reducer developed in this study demonstrates a higher reduction ratio and improved shock absorption. The performance of this newly proposed reducer has been verified through experimental analysis. It was confirmed that by minimizing drive losses, the system has high backdrivability, delivering a torque of 15 Nm. Additionally, it was observed that the system showed an immediate response without backlash to fine input vibrations.

• Journal of Aerospace System Engineering
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• v.16 no.3
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• pp.42-51
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• 2022

An eVTOL aircraft, which is required to operate with low pollution/low noise in urban environments, mostly use battery-powered electric propulsion systems as power sources, not traditional propulsion systems such as reciprocating or turbine engines. Accordingly, certification preparation for the electric propulsion system and securing the safety of the electric propulsion system, are important issues. In the U.S., special technical standards equivalent to FAR Part 33 were issued to certify electric engines, and in Europe, various special conditions were established to certify electric propulsion systems. Thus, in Korea, the technical standards for the electric propulsion system for eVTOL aircraft must also be prepared in line with the U.S. and Europe. In this paper, SC E-19, the technical standard of the electric/hybrid propulsion system (EHPS) in special conditions, was analyzed. Additionally, securing the safety of the electric propulsion system of the aircraft are proposed, through the collaboration of SC E-19 technical standards with the existing aircraft safety evaluation procedure ARP 4761. Finally, through a case study of the Ehang 184 electric propulsion system, it has been confirmed that the proposed safety assurance method is applicable at the aircraft level.

• Journal of the Korean housing association
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• v.20 no.4
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• pp.89-102
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• 2009

The purpose of this study is to investigate the influence the need for improvements to dormitory environments and to study the stress from school-life according to residential satisfaction in dormitories and housing. For the purpose of this study, a survey was conducted including a questionnaire consisting of a residential satisfaction scale, a need of dormitory environment improvement scale, and a school-life stress scale. The subjects were 453 special purpose students in Daegu and Gyeongsangbuk-do who all live in a dormitory. Factor analysis, Cronbach' $\alpha$ and MANOVA were employed for data analysis, and Scheffe test was used for post-hoc analysis. First, the lower group the satisfaction of a physical residential environment in a dormitory, the more likely it is that the dormitory environment need improvement. The result of this study suggests that dormitory students are much more sensitive to conditions relating to physical residential satisfaction than to sociopsychological residential satisfaction. Also, the residents believe that change to these physical residential conditions facilitate an improvement to sociopsychological residential satisfaction. Moreover, when the satisfaction of a physical residential environment is lower group, more perceptive stress occurs from academic, health and personal factors while a lower satisfaction for the sociopsychological residential environment results in a more perceptive stress from the environment. The result of this study suggests that dormitory conditions indicate the necessity of improving the environment to adapt well to school-life, thus reducing stress. Also when simply providing a supplementary physical residential environment the sociopsychological residential environment should be considered, as this can cause conflicts between roommates. Second, the lower group the satisfaction for a physical residential environment in housing, the more likely it is that the dormitory environment need improvement. The result of this study suggests that for environments of inadequate housing there is a strong urge towards needing more independence and a better living environment. Third, when group feel there is a more substantial difference in the physical residential environment between dormitories and housing, it is more likely it is that the dormitory environment need to be improved. Also, when they feel there is more substantial difference in the sociopsychological residential environment between dormitories and housing, a more perceptive stress is detected from the environment. The result of this study suggests that dormitory students want to have the same level of conditions as those provided in housing. Also, dormitory students want to need more physical environment improvement than sociopsychological environment improvement.