• Journal of Biomedical Engineering Research
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• v.26 no.6
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• pp.373-381
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• 2005

The respiratory and heart beat signals are the fundamental physiological signals for sleep monitoring in the home. Using the air mattress sensor system, the respiration and heart beat movements can be measured without any harness or sensor on the subject's body which makes long term measurement difficult and troublesome. The differential measurement technique between two air cells is adopted to enhance the sensitivity. The concept of the balancing tube between two air cells is suggested to increase the robustness against postural changes during the measurement period. With this balancing tube, the meaningful frequency range could be selected by the pneumatic filter method. The mathematical model for the air mattress and balancing tube was suggested and the validation experiments were performed for step and sinusoidal input. The results show that the balancing tube can eliminate the low frequency component between two cells effectively. This technique was applied to measure the respiration and heart beat on the bed, which shows the potential applications for sleep monitoring device in home. With the analysis of the waveform, respiration intervals and heart beat intervals were calculated and compared with the signal from conventional methods. The results show that the measurement from air mattress with balancing tube can be used for monitoring respiration and heart beat in various situations.

• Journal of the Korean Society of Industry Convergence
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• v.18 no.4
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• pp.216-223
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• 2015

Recently Manipulation capability is important for a robot. Interaction between a robot hand and objects can be properly controlled only is suitable sensors are available. Recently the tendency is to create robot hands more compact and high integrated sensors system, in order to increase the grasping capability and in order to reduce cabling through the finger, the palm and the arm. As a matter of fact, miniaturization and cabling harness represents a significant limitation to the design of small sized embedded sensor. Ongoing work is focusing on a flexible manipulation system, which consists of a dual flexible multi-fingered hand-arm system, and a dual active vision system.

• Journal of the Korean Ceramic Society
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• v.33 no.2
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• pp.192-202
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• 1996

In Li0.4Ca0.05AlP0.5Si0.75O4.5 composition glass, glass-ceramic having a near 100% crystallinity after nucleation heat treatment of 74$0^{\circ}C$/2 h and crystallization heat treatment of 90$0^{\circ}C$/2 h and in-situ TiO2 whisker reinforced glass-ceramic after heat treatment of 105$0^{\circ}C$ for 20 h were fabricated with the addition of 4% TiO2 as a nucleating agent. With these materials a ball-on-disc type wear test was conducted in order to examine the effect of TiO2 whisker prepcipitation on ambient and high temperature wear properties of the glass-ceramic. Wear test results indicated that all specimens exhibited micro-fracture wear mechanism in ambient temperature. As temperature increased the wear rates of the materials were increased. However the in-situ TiO2 whisker reinforced glass-ceramic exhibited the lowest wear rate over the test temperature range. This resulted from the improvement of harness and fracture toughness of the material as the glass converted into the glass-ceramic followed by precipitation of TiO2 whiskers throughout the glass-ceramic matrix.

• Journal of the Speleological Society of Korea
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• no.61
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• pp.65-82
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• 2000

The remarkable development of information technology today is significantly increasing the desire for related services as it allows one to process and transmit information fast and accurately as well as in an efficient way. Particularly, the spread of the Internet even changes our life pattern, not to mention allowing us to provide or share information. One of the most typical example is electronic commerce. The e-commerce industry, which is build upon informations super high way, is growing rapidly, backed on the development of communications technology and the combination of various media. Companies are active In embracing and utilizing the cutting-edge information technology, whereas the tourism industry in general is still at a rudimentary stage. Therefore, it is expected that the industry will harness e-commerce in many aspects. Tourism, in its characteristic, has a variety of sectors, and cross-sector cooperation is essential. Therefore, the industry can provide better services by connecting or integrating network systems and taking advantage of e-commerce, while it is of no less importance to have informal ion system for promoting products. This thesis will look into and the basic concept and role of e-commerce as well as the existing tourism information system. It will also study ways to make good use of e-commerce by adopting it into the tourism information system.

• Environmental Engineering Research
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• v.24 no.4
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• pp.566-571
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• 2019

One-pot hydrothermal route was adopted to synthesize Al:BiVO₄, at 4 h and 8 h reaction durations, by adding 1% aluminiumoxide powder (w/v) to the precursors. The products were investigated using several characterization techniques that conform a significant morphological change and a decrease in bandgap energy of the materials upon Al modification of scheelite monoclinic bismuth vanadate matrix at both hydrothermal durations. Antibacterial experiments were performed against methicillin-resistant Staphylococcus aureus in visible light condition to harness the photoxidation property of Al-doped BiVO₄ and compare to that of unaltered BiVO₄. Minimum inhibitory concentration of the synthesized materials was identified. The results indicate that Al-doping on BiVO₄ has a significant effect on its photocatalytic antibacterial performance. Al:BiVO₄ synthesized at 8 h hydrothermal treatment parades excellent sunlight-driven photocatalysis compared to the one synthesized at 4 h.

• Journal of the Korean Data and Information Science Society
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• v.27 no.4
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• pp.1075-1081
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• 2016

The big data analysis has received much attention from the researchers working in various fields because the big data has a great potential in detecting or predicting future events such as epidemic outbreaks and changes in stock prices. Reflecting the current popularity of big data analysis, many authors have proposed methods tracking influenza epidemics based on internet-based information. The recently proposed 'autoregressive model using Google (ARGO) model' (Yang et al., 2015) is one of those influenza tracking models that harness search queries from Google as well as the reports from the Centers for Disease Control (CDC), and appears to outperform the existing method such as 'Google Flu Trends (GFT)'. Although the ARGO predicts well the outbreaks of influenza, this study demonstrates that a classical seasonal autoregressive integrated moving average (SARIMA) model can outperform the ARGO. The SARIMA model incorporates more accurate seasonality of the past influenza activities and takes less input variables into account. Our findings show that the SARIMA model is a functional tool for monitoring influenza epidemics.

• Journal of the Korean Ceramic Society
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• v.35 no.1
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• pp.66-78
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• 1998

the microstructure and mechanical properties of seeded and ball-milled dry gels prepared by boehmite sol-gel method were discussed. The densification of seeded gels was improved with increasing seed content namely the number of seed The number of seed was 1.09, 3.35, 5.72${\times}$1012/cm3 boehmite when seeded with 1, 3, 5wt% respectively The ball milled gel contained about 0.5wt% seed and the number of seed was 4.72${\times}$1012/cm3 boehmite. The sintered density of 5wt% seeded gel was below 80% when sintered at 1300$^{\circ}C$ for 1h. On the other hand that of ball milled gel was very improved and reached to 97% In the case of 3wt% seeded gels the density over 97% was attained when sintered at 1500$^{\circ}C$for 1h. and the grain of the sintered body was several micrometers in size. However the sintered body of ball milled gel showed grain size of submicrometer when sintered at 1300$^{\circ}C$ for 1h. And this specimen showed highest harness value of 1900kg/mm2 The fracture toughness increased with increasing sintering temperature. The sintered body of ball milled gel showed the largest grain size and the highest fracture toughness without regard to sint-ering temperature.

• Journal of the Ergonomics Society of Korea
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• v.25 no.1
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• pp.43-49
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• 2006

A laboratory study was conducted to evaluate if two different age groups(young vs. old) had differences in walking velocity and heel contact velocity and, furthermore, if these gait characteristics could adversely influence initial friction demand characteristics(i.e. RCOF) and the likelihood of slip-initiation. Twenty eight(14 younger and 14 older adults) participated in the study. While wearing a safety harness, all participants walked at their preferred gait speed for approximately 20 minutes on the linear walking track(1.5m× 20m) consisting of two floor-mounted forced plates. During subsequent 20 cameras, respectively. The results indicated that older adults walked slower(i.e., slower whole body center-of-mass velocity), exhibited lower heel contact velocity, and produced lower initial friction demand characteristics (i.e. RCOF) in comparison to younger adults. However, ANCOVA indicated that the diferences in heel contact velocity between the two age groups were due to the effects of walking velocity. The bivariate analysis further suggested that walking velocity was correlated to RCOF and heel contact velocity, while heel contact velocity was not found to be correlated to RCOF. In conclusion, could be a better indicator for predicting initial friction demand characteristics(i.e. RCOF) not hel contact velocity.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.4
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• pp.1241-1250
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• 1996

The characteristics of fatigue cumulative damage and fatigue life of 8-harness satin woven CFRP composites with a circular hole under constant amplitude and 2-level block loading are estimated by Stochastic Makov chain model. It is found in this study that the fatigue damage accumulation behavior is very random and the fatigue damage is accumulated as two regions under constant amplitude fatigue loading. In constant amplitude fatigue loading the predicted mean number of cycles to a specified damage state by Markov chain model shows a good agreement with the test result. The predicted distribution of the fatigue cumulative damage by Markov chain model is similar to the test result. The fatigue life predictions under 2-level block loading by Markov chain model revised are good fitted to the test result more than by 2-parameter Weibull distribution function using percent failure rule.

• Journal of the Korea Society of Computer and Information
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• v.23 no.2
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• pp.63-70
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• 2018

Safety management agent manages the risk behavior of the worker with the naked eye, but there is a real difficulty for one the agent to manage all the workers. In this paper, IoT device is attached to a harness safety belt that a worker wears to solve this problem, and behavior data is upload to the cloud in real time. We analyze the upload data through the deep learning and analyze the risk behavior of the worker. When the analysis result is judged to be dangerous behavior, we designed and implemented a system that informs the manager through monitoring application. In order to confirm that the risk behavior analysis through the deep learning is normally performed, the data values of 4 behaviors (walking, running, standing and sitting) were collected from IMU sensor for 60 minutes and learned through Tensorflow, Inception model. In order to verify the accuracy of the proposed system, we conducted inference experiments five times for each of the four behaviors, and confirmed the accuracy of the inference result to be 96.0%.