• Journal of Korea Society of Industrial Information Systems
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• v.25 no.2
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• pp.129-136
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• 2020

Recognizing finger movements have been used as a intuitive way of human-computer interaction. In this study, we implement an wearable device for finger motion recognition and evaluate the accuracy of several ML (Machine learning) techniques. Not only HMM (Hidden markov model) and DTW (Dynamic time warping) techniques that have been traditionally used as time series data analysis, but also NN (Neural network) technique are applied to compare and analyze the accuracy of each technique. In order to minimize the computational requirement, we also apply the pre-processing to each ML techniques. Our extensive evaluations demonstrate that the NN-based gesture recognition system achieves 99.1% recognition accuracy while the HMM and DTW achieve 96.6% and 95.9% recognition accuracy, respectively.

• Journal of Korea Multimedia Society
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• v.9 no.5
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• pp.681-690
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• 2006

With the rapid development of network and multimedia technologies, computer mediated communication has been realized and there has been a great potential to use and research on asynchronous voice communication systems. This paper reports a case study where 6 groups(3 for documentation work, 3 for software development) of 24 people who used voice mail when carrying out their projects. The purpose of this study is to obtain an overall understanding of usability of voice mail which is a typical example of asynchronous voice communication systems, under a particular situation where project works are performed. Through the study, we came to understand general purposes of usage of voice mail, patterns of using it revealed during the project process, different ways of using it according to different types of projects, and reasons why people are currently not likely to use voice mail. The results hopefully provide systems developers with a guideline to understand the nature of voice mail from users' perspectives.

• Journal of Korean Academy of Oral Health
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• v.42 no.4
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• pp.167-174
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• 2018

Objectives: The aim of this study was to analyze the accessibility of dental care services among individuals with precarious employment in South Korea. Methods: We used the $9^{th}$ wave of the Korean Health Panel data (2015) and included 7,736 wage and non-wage earners in our study. We determined precariousness in the labor market as a combination of employment relationship and job income, and categorized individuals based on this into the following four groups: Group A comprising those who report job and income security, Group B comprising those who experience job insecurity alone, Group C comprising those who report a stable job but low income, and Group D comprising those who experience both job and income insecurity. Accessibility to dental care services was determined by experience of unmet dental care needs and unmet dental care needs caused primarily by financial burden. Logistic regression analyses were used to assess the effect of precarious work on access to dental care services. Results: Individuals with job insecurity (Group B; OR=1.445; 95% CI=1.22-1.70) and both job and income insecurity (Group D; OR=1.899; 95% CI=1.61-2.24) were more likely to have unmet needs than the comparison group. Both groups B and D were also 2.048 (95% CI=1.57-2.66) times and 4.435 (95% CI =3.46-5.68) times more likely, respectively, to have unmet dental care needs caused by financial burden. Education status, health insurance, and health status were all also effective factors influencing unmet dental care needs. Conclusions: Unstable employment and low income resulted in diminished access to dental care services. Therefore, governments should consider health policy solutions to reduce barriers preventing individuals with employment and income instability from accessing adequate dental care.

• Journal of the Korea Convergence Society
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• v.12 no.1
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• pp.89-97
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• 2021

Recently, as the importance of forced indoor living has increased in the untact era, the connection and relationship between space environments is increasing. That is, the smart interaction environment for providing services in various spaces collects and processes a number of surrounding environment information through various sensors to provide desired information according to the required place and time. In this environment, a new type of interaction paradigm is needed for the user to select and focus on environmental information. In this paper, we provide guidelines based on models and patterns for designing various interactions around space. Through interaction model-based technology, we provide guidelines for space-oriented interaction design. We propose an ideal interaction environment through guideline-based patterns and templates. Finally, by providing a space-oriented interaction environment suitable for smart interaction, users can freely obtain desired information.

• Membrane Journal
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• v.32 no.3
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• pp.173-180
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• 2022

Presence of ammonia in drinking water is very toxic to human health. Soluble ammonia contaminates ground water due to activities such as the use of fertilizer in crop, industrial effluents and burning of fossil fuel. Even low concentration of ammonia present in water will damage aqua environment such as marine organism. Membrane technology is an important process to remove ammonia from effectively from water. Flat sheet membrane, membrane contactor and membrane distillation are some of the methods used for water purification from ammonia. Membrane contractor is an efficient process in which ammonia is removed through liquid-gas or liquid-liquid mass transfer without change of phase unlike membrane distillation. However, the cost of ammonia removal in this method is high due to maintenance of very high pH. Zeolite has excellent ion exchange ability that enhances its ability to interact with ammonia and adsorb from wastewater. Mixed matrix membranes containing zeolite enhance the efficiency of ammonia adsorption and separation from wastewater. In this review the above discussed issues are summarized in detail.

• Journal of Korea Water Resources Association
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• v.56 no.2
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• pp.125-137
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• 2023

In marine environments, plastics have become more abundant due to increasing plastic use. Especially, in coastal regions, particles may remain for a long time, and they interact with flows, wind, sand and human activities. This study aimed thus to observe how plastic debris interacts with and escape from sediments. A series of experiments were conducted in order to gain a better understanding of particle release from coastal sediments into water body. An oscillating water tunnel was built for the experiments, and used to generate oscillatory flows of relatively high Reynolds number and induce sediment transport. Spherical plastic particles of three different sizes was used in lieu of plastic debris in environments. It was observed that release of the particles was directly related to change of bedform, which is in turn determined by the flow condition. Also smaller particles tend to escape the sediment more readily. Critical values for dimensionless parameters are proposed.

• 한국노년학
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• v.31 no.4
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• pp.1103-1118
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• 2011

This study aims to examine the effects of employment on the physical health, psychological function, and life satisfaction of the elderly. Participants were 4,165 persons (men 1,739, women 2,426) aged 65 over. Physical health was composed of ADLs(Activities of daily living), pains, and disorders. Psychological function was measured by cognitive functions (subtraction, instruction execution, memory test, and item use) and emotional difficulty. Life satisfaction, work satisfaction, and work level were also measured. Major findings in this study are as follows: First, gender, marriage, and education level had significant effects on the participants' life satisfaction, but religion and financial incomes did not. Second, employment had significant effects on their physical health, psychological function, and life satisfaction. Third, pain, cognitive functions, emotional difficulty, and work satisfaction had significant effects on the life satisfaction of the working elderly. But, work level and incomes had not significant effects on the elderly's life satisfaction. In addition, an interaction between cognitive functions and emotional difficulty on life satisfaction was found.

• Journal of Internet Computing and Services
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• v.24 no.6
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• pp.23-29
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• 2023

As an effort to maximize the immersiveness of user experience in virtual reality, there have been constant efforts to provide a user with tactile sensation by providing haptic feedback. Most of the haptic feedback methods, however, can create only limited or unrealistic haptic sensations since they utilize affordable actuators such as a vibrotactile actuator. When it comes to martial arts training or a game, the limitation of such haptic feedback is apparent due to the significant difference between the physical impact of hitting an object and the sensation departed from a vibrotactile actuator. Noting this, we proposed a haptic impact system that can create a haptic impact when the user hits a virtual object with the fist. The haptic interface uses a quick-return mechanism that can deliver haptic impact feedback to a user's fist. The realism of the haptic impact was evaluated by conducting a human-subject experiment. The results indicate a significant effect of haptic feedback on the realism of the virtual impact.

• Radiation Oncology Journal
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• v.21 no.3
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• pp.216-221
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• 2003

Purpose: To investigate the modulation of radiosensitivity by celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, on cancer cells over- and under-expressing COX-2. Materials and Methods: A clonogenic radiation survival analysis was performed on A549 human lung and MCF-7 human breast cancer cell lines incubated in both 1 and $10\%$ fetal bovine serum (FBS) containing media. The apoptosis in both cell lines was measured after treatment with radiation and/or celecoxib. Results: Celecoxib enhanced the radiation sensitivity of the A549 cells in the medium containing the $10\%$ FBS, with radiation enhancement ratios of 1.58 and 1.81 respectively, at surviving fractions of 0.1, with $30\muM\;and\;50\muM$ celecoxib. This enhanced radiosensitivity disappeared in the medium containing the $1\%$ FBS. Celecoxib did not change the radiation sensitivity of the MCF-7 cells in either media. The induction of apoptosis by celecoxib and radiation was not synergistic in either cell line. Conclwsion: Celecoxib, a selective COX-2 inhibitor, preferentially enhanced the effect of radiation on COX-2 over-expressing cancer cells compared to the cells with a low expression, and this effect disappeared on incubation of the cells during drug treatment in the medium with suboptimal serum concentration. Apoptosis did not appear to be the underlying mechanism of this radiation enhancement effect due to celecoxib on the A549 cells. These findings suggest radiosensitization by a selective COX-2 inhibitor is COX-2 dependent.

• Archives of design research
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• v.18 no.3 s.61
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• pp.85-94
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• 2005

Most of product designers use 3D CAD system as a inevitable design tool nowadays and many new products are developed through a concurrent engineering process. However, it is very difficult for novice designers to get the sense of reality from modeling objects shown in the computer screens. Such a intangibility problem comes from the lack of haptic interactions and contextual information about the real space because designers tend to do 3D modeling works only in a virtual space of 3D CAD system. To address this problem, this research investigate the possibility of a interactive quantified structure simulation for product design using AR(augmented reality) which can register a 3D CAD modeling object on the real space. We built a quantified structure simulation system based on AR and conducted a series of experiments to measure how accurately human perceive and adjust the size of virtual objects under varied experimental conditions in the AR environment. The experiment participants adjusted a virtual cube to a reference real cube within 1.3% relative error(5.3% relative StDev). The results gave the strong evidence that the participants can perceive the size of a virtual object very accurately. Furthermore, we found that it is easier to perceive the size of a virtual object in the condition of presenting plenty of real reference objects than few reference objects, and using LCD panel than HMD. We tried to apply the simulation system to identify preference characteristics for the appearance design of a home-service robot as a case study which explores the potential application of the system. There were significant variances in participants' preferred characteristics about robot appearance and that was supposed to come from the lack of typicality of robot image. Then, several characteristic groups were segmented by duster analysis. On the other hand, it was interesting finding that participants have significantly different preference characteristics between robot with arm and armless robot and there was a very strong correlation between the height of robot and arm length as a human body.