• Journal of Biomedical Engineering Research
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• v.24 no.4
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• pp.293-299
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• 2003

In this paper, the correlation of Pressure drop about the Newtonian and non-Newtonian fluid was investigated experimentally for vibrating intravascular lung assist device (VIVLAD) and we determined correlation equation to make a prediction about Pressure drop for designing VIVLAD. Design conditions to predict the pressure drop of the modules were studied through an experimental modeling before inserting the artificial lung assist device into as venous. Experiments were performed by distilled water, glycerol/water mixed solution(40% glycerol) of Newtonian fluids. and the bovine blood of non-Newtonian fluids. These fluids were flowed outside and parallel of hollow fiber membranes. Also we measured pressure drop according to the number of the fiber membranes which ware inserted into the inside diameter of shell of 3 cm, and developed the prediction equations by curve fitting method based on correlation between the experimental pressure drop and the frontal area or the packing density of device. The result showed that the Pressure drop and the friction factor of the water/glycerol mixed solution were similar to that of bovine blood. It was showed that the water/glycerol mixed solution (40% glycerol) could be used for measuring the pressure drop and the friction factor instead of the bovine blood. Also, we could estimate the prediction equation of pressure drop and friction factor as the function of Packing density at the number of hollow fibers. We obtained the reliance of the prediction equations because the pressure drop and the friction factor measured from the experiments were similar to that from the prediction equation. These results may be used to further usefulness for the design of VIVLAD.

• Korean Journal of Materials Research
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• v.13 no.1
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• pp.11-17
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• 2003

DC characteristics of recessed gate 4H-SiC MESFET were investigated using the device/circuit simulation tool, PISCES. Results of theoretical calculation were compared with the experimental data for the extraction of modeling parameters which were implemented for the prediction of DC and gate leakage characteristics at high temperatures. The current-voltage analysis using a fixed mobility model revealed that the short channel effect is influenced by the defects in SiC. The incomplete ionization models are found out significant physical models for an accurate prediction of SiC device performance. Gate leakage is shown to increase with the device operation temperatures and to decrease with the Schottky barrier height of gate metal.

• Journal of Internet Computing and Services
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• v.24 no.2
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• pp.57-66
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• 2023

Currently, a new energy system is emerging that implements consumption reduction by improving energy efficiency. Accordingly, as smart grids spread, the rate system by timing is expanding. The rate system by timing is a rate system that applies different rates by season/hour to pay according to usage. In this study, external factors such as temperature/day/time/season are considered and the time series prediction model, LSTM, is used to predict energy power usage data. Based on this energy usage prediction model, energy usage charges are reduced by analyzing usage patterns for each device and transferring power energy from the maximum load time to the light load time. In order to analyze the usage pattern for each device, a clustering technique is used to learn and classify the usage pattern of the device by time. In summary, this study predicts usage and usage fees based on the user's power data usage, analyzes usage patterns by device, and provides customized demand transfer services based on analysis, resulting in cost reduction for users.

• Korean Journal of Hydrosciences
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• v.6
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• pp.1-11
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• 1995

A plunge pool is often employed as an energy-dissipating device at the end of a spillway or a pipe culvert. A jet from spillways or pipes frequently generates a scour hole which threaten the stability of the hydraulic structure. Existing scour prediction formulas of plunge pool of spillways or pipe culverts give a wide range of scour depths, and it is, therefore, difficult to accurately predict those scour depths. In this study, a new experimental method and new sour prediction formulas under submerged circular jet for large bed materials with shallow tailwater depths were developed. A major variable, which was not used in previous scour prediction equations, was the ratio of jet size to bed material size. In this study, jet momentum acting on a bed particle and jet diffustion theory were employed to derive scour prediction formulas. Four theoretical formulas were suggested for the two regions of jet diffusion, i.e., the region of flow establishment and the region of established flow. The semi-theoretically developed scour prediction formulas showed close agreement with laboratory experiments performed on movable bed made of large spherical particles.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.6
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• pp.1113-1122
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• 2020

Recently, as violent crimes of crime without reason (Korea : Do not ask), women and the elderly are getting serious. In the existing system, many CCTVs are installed, but it is difficult to prevent crime due to only follow-up measures after a crime occurs. This device prevents crime through this device for incidents in shaded areas and closed spaces such as apartments and buildings. To do this, we research this technology to develop products and software. It sends an alarm signal using communication technology to a specific place where you want to receive an event of an alarm or a CCTV device operated using image analysis big data technology and convergence sensor technology for a specific target of the behavior expected to be a crime or movement. Develop the device. This development device researches and develops this device and supplies low-cost devices to consumers, which is used as a device that predicts the occurrence of crime in advance, processes it as an alarm signal in real time, and transmits it, and constitutes a standalone device and a server. Will provide the device to be connected.

• Proceedings of the Korean Magnestics Society Conference
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• 2003.12a
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• pp.113-113
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• 2003

• The Journal of Society for e-Business Studies
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• v.21 no.1
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• pp.147-163
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• 2016

Gender information of a smart device user is essential to provide personalized services, and multi-modal data obtained from the device is useful for predicting the gender of the user. However, the method for utilizing each of the multi-modal data for gender prediction differs according to the characteristics of the data. Therefore, in this study, an ensemble method for predicting the gender of a smart device user by using three classifiers that have text, application, and acceleration data as inputs, respectively, is proposed. To alleviate privacy issues that occur when text data generated in a smart device are sent outside, a classification method which scans smart device text data only on the device and classifies the gender of the user by matching text data with predefined sets of word. An application based classifier assigns gender labels to executed applications and predicts gender of the user by comparing the label ratio. Acceleration data is used with Support Vector Machine to classify user gender. The proposed method was evaluated by using the actual smart device log data collected from an Android application. The experimental results showed that the proposed method outperformed the compared methods.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.9 no.3
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• pp.209-214
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• 2015

The purpose of this study was to examine (1) the influence of the word-prediction function on the sentence generation speed and (2) the necessity, convenience, and satisfaction of the word-prediction function of the AAC keyboard. A total of 10 adults with cerebral palsy participated and the word-prediction function of the Korean high-tech AAC device called "MyTalkie Smart" keyboard was used for this study. Participants were required to generate sentence as voice outputs using a word-prediction function and letters direct-input function respectively, then they were required to evaluate the necessity, convenience, and satisfaction using a five-point Likert scale. Other user requirements were examined using a free feedback. The results of this study presented that the sentence generation speeds were faster when participants used a word-prediction function than using a letters direct-input function. However, there was no statistically significant difference between these two input methods, and it might be due to the lack of time to practice the new device. Participants showed positive responses for the necessity, convenience, and satisfaction of the word-prediction function.

• Journal of Korea Multimedia Society
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• v.15 no.12
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• pp.1506-1516
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• 2012

In a ship block logistics application, acquisition of locations is required in order to identify location of the ship blocks. A Smart device equipped with a GPS sensor can be used as a mobile client for a ship block logistics application. However the precision of GPS components on a commercial smart device is not high enough. Therefore, using the GPS for localization may produce significant positioning errors in a ship block logistics system. This paper proposes a method to reduce errors in measuring locations using a smart device. Based on the knowledge of how the location information is used in a ship block logistics application, and the predictability of the client's moving line based on geographical layout of a shipyard area, our proposed technique enables a better prediction of the ship blocks location. Performance evaluation shows that the proposed technique can significantly reduce the positional error.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.10
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• pp.660-666
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• 2015

Surface acoustic wave(SAW) device is used for transporting and patterning micro-scale particles such as cells. In this research, velocity of particles was investigated moved by SAW device with two types of interdigital electrode transducers(IDTs) under various conditions. SAW devices which have single IDTs and double IDTs were designed and fabricated. On the previous studies, resultant velocities of particles were predicted considering output power and power ratio between IDTs-shape. For more accurate prediction, power loss in SAW device and a power difference between two types of IDTs-shape were considered. Maximum error between the test results and predicted values was 5 % so the power loss must be considered in the velocity prediction of the particles.