• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.2
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• pp.99-102
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• 2011

Objectives: Acetone/triacetine method for clearing cellulose ester membrane (CEM) filter has been a popular method for air-borne asbestos analysis. However, as a weakness of this method, it is time consuming to analyses asbestos samples after sampling. Crystalclear method can be used to analyses asbestos samples promptly after sampling. Although a strength of crystal clear method exists, there was little valid studied for the method. This study was conducted to compare acetone/triacetine method with crystalclear one for analysing asbestos sample. Methods: Test samples made in three different concentration ranges(low, medium and high concentration) were analysed by phase contrast microscopy after acetone/triacetine and crystalclear method treatment respectively. Results: We did not find statistical difference in analysed results between two methods, which were conducted in three different concentrations ranges. Conclusions: We concluded that crystalclear method can be used as clearing method for air-borne asbestos analysis instead of acetone/triacetine method.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1997.11a
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• pp.413-422
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• 1997

Fire characteristics of a typical apartment building in Korea was studied through full scale experiment and zone model simulation. The fire was ignited at the living room and allowed to spread to other parts of a single unit in a five storied apartment building. Various data including temperatures, species concentrations, and images were collected in the experiment. A zone model(CFAST) was used to analyze the same apartment building that represents the average households in Korea. The results were compared with a full scale experiments. While CFAST allows one compartment involved with fire, the experiment allowed the fire to spread to other compartments. Therefore, the comparison between experimental data and Zone-Model data is valid until the living-room fire spread to other parts of the apartment. Flashover occurred at approximately 380 seconds in a fire experiment, and at approximately 420 seconds in Zone-Model. Based on all of data between experimental data and Zone-Model data, it is concluded that the safe escape time is about 250 seconds.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.4
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• pp.651-660
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• 2008

The widespread use of public networks, such as the Internet, for the exchange of sensitive data that need a severe security, like legally valid documents and business transactions. At the same time public-key certificates used for sensitive data interchange form the viewpoint of data integrity and authentication. But there are some weakness of data transfer capacity and security in public key infrastructure(PKI) environment. This paper use the RSA one-way accumulator to realize an efficient and dynamic authenticated dictionary, where untrusted directories provide cryptographically verifiable answers to membership queries on a set maintained by a trusted source.

• Advances in concrete construction
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• v.5 no.6
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• pp.659-669
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• 2017

Grouts compared to other material sources, could be highly sensitive to cold weather conditions, especially when the compressive strength is the matter of concern. Grout as one the substantial residential building material used in retaining walls, rebar fixation, sidewalks is in need of deeper investigation, especially in extreme weather condition. In this article, compressive strength development of four different commercial grouts at three temperatures and two humidity rates are evaluated. This experiment is aimed to assess the grout strength development over time and overall compressive strength when the material is cast at low temperatures. Results represent that reducing the curing temperature about 15 degrees could result in 20% reduction in ultimate strength; however, decreasing the humidity percentage by 50% could lead to 10% reduction in ultimate strength. The maturity test results represented the effect of various temperatures and humidity rates on maturity of the grouts. Additionally, the freeze-thaw cycle's effect on the grouts is conducted to investigate the durability factor. The results show that the lower temperatures could be significantly influential on the behavior of grouts compared to lower humidity rates. It is indicated that the maturity test could not be valid and precise in harsh temperature conditions.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.9
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• pp.321-331
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• 2021

This study examines the impact of Information and Communication Technology (ICT) and the role of Malaysian local wisdom called "Ugahari" in managing Work-Life Balance (WLB) during the COVID-19 pandemic in Malaysia. Data was obtained through online and offline surveys which were distributed to the agencies in the public and private sectors spread across Kuala Lumpur, Selangor and Pura Jaya. Overall 466 respondents were found to have given valid and complete responses. This research utilized the Partial Least Squares Structural Equation Modelling. It was found that the use of the ICT during Work from Home (WFH) helped workers to have relatively high flexibility where they could easily expand or contract one domain to meet the demands of another domain. At the same time it also offered high permeability where aspects of one domain entered another domain. This encourages workers to integrate their roles and achieve broad work autonomy. Furthermore, this situation then gives rise to a high level of interference at the boundary between work and family domains. On the other hand Ugahari reduces the level of interference caused by ICT use and encourages workers to compartmentalize their respective roles. Thus, ICT and Ugahari's behavior can play a role and complement each other in the context of realizing worker well-being.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.2
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• pp.500-521
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• 2021

Echocardiography, an ultrasound scan of the heart, is regarded as the primary physiological test for heart disease diagnoses. How an echocardiogram is interpreted also relies intensively on the determination of the view. Some of such views are identified as standard views because of the presentation and ease of the evaluations of the major cardiac structures of them. However, finding valid cardiac views has traditionally been time-consuming, and a laborious process because medical imaging is interpreted manually by the specialist. Therefore, this study aims to speed up the diagnosis process and reduce diagnostic error by providing an automated identification of standard cardiac views based on deep learning technology. More importantly, based on a brand-new echocardiogram dataset of the Asian race, our research considers and assesses some new neural network architectures driven by action recognition in video. Finally, the research concludes and verifies that these methods aggregating dynamic information will receive a stronger classification effect.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.6
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• pp.2799-2823
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• 2019

With the help of learning analytics, MOOCs have wider potential to succeed in learning through promoting self-regulated learning (SRL). The current study aims to apply and validate visualization design guidelines for a MOOC dashboard to enhance such SRL capabilities based on learning analytics. To achieve the research objective, a MOOC dashboard prototype, LM-Dashboard, was designed and developed, reflecting the visualization design guidelines to promote SRL. Then, both expert and learner participants evaluated LM-Dashboard through iterations to validate the visualization design guidelines and perceived SRL effectiveness. The results of expert and learner evaluations indicated that most of the visualization design guidelines on LM-Dashboard were valid and some perceived SRL aspects such as monitoring a student's learning progress and assessing their achievements with time management were beneficial. However, some features on LM-Dashboard should be improved to enhance SRL aspects related to achieving their learning goals with persistence. The findings suggest that it is necessary to offer appropriate feedback or tips as well as to visualize learner behaviors and activities in an intuitive and efficient way for the successful cycle of SRL. Consequently, this study contributes to establishing a basis for the visual design of a MOOC dashboard for optimizing each learner's SRL.

• Journal of Sensor Science and Technology
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• v.28 no.3
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• pp.182-186
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• 2019

When a camera is employed for 3D sensing, accurate camera calibration is vital as it is a prerequisite for the subsequent steps of the sensing process. Camera calibration is usually performed by complex mathematical modeling and geometric analysis. On the other contrary, data learning using an artificial neural network can establish a transformation relation between the 3D space and the 2D camera image without explicit camera modeling. However, a neural network requires a large amount of accurate data for its learning. A significantly large amount of time and work using a precise system setup is needed to collect extensive data accurately in practice. In this study, we propose a two-step neural calibration method that is effective when only a small amount of learning data is available. In the first step, the camera projection transformation matrix is determined using the limited available data. In the second step, the transformation matrix is used for generating a large amount of synthetic data, and the neural network is trained using the generated data. Results of simulation study have shown that the proposed method as valid and effective.

• The Journal of Fisheries Business Administration
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• v.49 no.4
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• pp.53-68
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• 2018

The industrial structure of Chuja Island is mainly occupied by fisheries. Since the fisheries resources have been depleted and the marine environment has been changed, the fishery industry has been hard to survive. It is the time when residents are looking for a breakthrough in the tourism industry. Market segmentation is a valuable tool in the establishment of marketing strategies. Segmentation of tourists by the same desire and motivation is an essential factor in identifying the characteristics of tourists. The research on market segmentation of tourism sector focuses mainly on demographic subdivision, psychological subdivision, and behavioral subdivision, so it is urgent to study geographical market segmentation. The purpose of this study is to present data that can be used to establish a marketing strategy for tourism promotion in Chuja Island by analyzing the tourism activities via subdivision market according to demographic characteristics, tourism behavior characteristics, and tourism motivation after grasping the geographical segment of tourists through empirical analysis. In this study, 285 valid samples were analyzed by frequency analysis, ${\chi}^2$ test, cluster analysis and ANOVA test.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.1
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• pp.572-583
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• 2019

This paper aims to assess the applicability of the Runge Kutta Discontinuous Galerkin-Direct Ghost Fluid Method to the internal explosion inside a water-filled tube, which previously was studied by many researchers in separate works. Once the explosive charge located at the inner center of the water-filled tube explodes, the tube wall is subjected to an extremely high intensity fluid loading and deformed. The deformation causes a modification of the field of fluid flow in the region near the water-structure interface so that has substantial influence on the response of the structure. To connect the structure and the fluid, valid data exchanges along the interface are essential. Classical fluid structure interaction simulations usually employ a matched meshing scheme which discretizes the fluid and structure domains using a single mesh density. The computational cost of fluid structure interaction simulations is usually governed by the structure because the size of time step may be determined by the density of structure mesh. The finer mesh density, the better solution, but more expensive computational cost. To reduce such computational cost, a non-matched meshing scheme which allows for different mesh densities is employed. The coupled numerical approach of this paper has fewer difficulties in the implementation and computation, compared to gas dynamics based approach which requires complicated analytical manipulations. It can also be applied to wider compressible, inviscid fluid flow analyses often found in underwater explosion events.