• Journal of Korea Multimedia Society
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• v.10 no.4
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• pp.421-431
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• 2007

Due to the rapid development of wireless communication technology, demands on data services in mobile computing environment are gradually increasing. In mobile computing environments, a mobile host began to use cache to overcome the weak point. Caching at mobile host could reduce the bandwidth consumption and query response time, but mobile host must maintain cache consistency. In this paper, we propose a cache consistency strategy to consider the period of data usage. The server allows an effective broadcasting by classifying data into two groups of periodic and non-periodic. By classifying the data, it prevent from elimination of cache after disconnection of periodic data by using expired time. By storing IR(Invalidation Report) messages, this scheme divides cached data by selection after disconnection. Consequently, we have shown much improvement in total consumption of bandwidth than the conventional scheme.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.2
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• pp.322-329
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• 2005

This paper describes a computer vision system based on active IR illumination for real-time gaze discrimination system. Unlike most of the existing gaze discrimination techniques, which often require assuming a static head to work well and require a cumbersome calibration process for each person, our gaze discrimination system can perform robust and accurate gaze estimation without calibration and under rather significant head movement. This is made possible by a new gaze calibration procedure that identifies the mapping from pupil parameters to screen coordinates using generalized regression neural networks (GRNNS). With GRNNS, the mapping does not have to be an analytical function and head movement is explicitly accounted for by the gaze mapping function. furthermore, the mapping function can generalize to other individuals not used in the training. To further improve the gaze estimation accuracy, we employ a reclassification scheme that deals with the classes that tend to be misclassified. This leads to a 10$\%$ improvement in classification error. The angular gaze accuracy is about $5^{circ}$horizontally and $8^{circ}$vertically. The effectiveness of our gaze tracker is demonstrated by experiments that involve gaze-contingent interactive graphic display.

• Aerospace Engineering and Technology
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• v.12 no.2
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• pp.147-155
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• 2013

The nominal radiometric calibration equation and additional five algorithms are applied in the infrared channel radiometric calibration for the COMS (Communication, Ocean, Meteorological Satellite) MI (Meteorological Imager). The processing end time of the radiometric calibration is directly related with the start time of geometric calibration processing since the geometric calibration processing is followed by that of the radiometric calibration. This paper describes comparison and analysis results for geometric calibration processing using two types of the radiometric calibration results, outputs from only the nominal radiometric calibration equation and outputs from the complete one (the nominal radiometric calibration equation with additional five algorithms), to propose a method with the earlier start time of the geometric calibration processing. Experimental results show that both of radiometric calibration results, from the nominal radiometric calibration equation with a fast processing speed and from the complete one with accurate radiometric values, can be used in the geometric calibration as the appropriate inputs because those processing results satisfied the requirements of geometric calibration processing accuracy. Thus the radiometric calibration results from the nominal radiometric calibration equation can be used to improve geometric calibration processing time.

• Journal of the Korean Chemical Society
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• v.61 no.6
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• pp.339-345
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• 2017

Carbonaceous adsorbent (CA-WTP) was prepared by heat treatment at $400^{\circ}C$ for 2 h in N2 atmosphere using waste tire powder (WTP). WTP and CA-WTP were first characterized by thermo-gravimetric analysis (TGA), energy dispersive X-ray spectrometer (EDS), scanning electron microscopy (SEM), specific surface area analysis (BET) and FT-IR spectroscopy. Then, they were tested as adsorbents for removal of Cd in water. CA-WTP exhibited much higher specific surface area and total pore volume than WTP itself and showed higher adsorption capacity for Cd. Equilibrium data of adsorption were analyzed using Freundlich and Langmuir isotherm models. It was seen that both Freundlich and Langmuir isotherms have correlation coefficient $R^2$ value larger than 0.95. The results of studies indicate that CA-WTP developed from WTP by heat treatment could be used as efficient adsorbent for the removal Cd from water.

• Journal of Korean Clinical Nursing Research
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• v.26 no.2
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• pp.186-197
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• 2020

Purpose: The purpose of this study was to develop a program for reinforcing the resilience of new nurses and relation-oriented organizational culture. Methods: An Intervention Research (IR) model was used to develop a program. Literature review, focus group interviews with nurses and need surveys were conducted from August to December 2018. Based on the results of the investigation, the researcher developed the content of a program. The program was revised by nurse managers for the content validation. Results: According to the results of the need surveys, 58.8% of the participants thought relation-oriented culture was the most ideal, and 61.8% of the participants wanted to participate in a program for organizational culture improvement. In the focus group interview, not only new nurses but also wards and nursing organizations should be a target subject of the program. Reinforcement of resilience and relation (3R) program was developed as a one-year course, which includes a 'mentor-mentee' program and a 'thanks' program. Conclusion: It would contribute to improving the resilience of new nurses and creating a relation-oriented organizational culture by 3R program. The 3R program could play a role as expanded program from an existing pragmatic short-term training program for improving the competencies or communication skills of new nurses.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.2
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• pp.477-483
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• 2004

This paper describes preliminary results we have obtained in developing a computer vision system based on active IR illumination for real time gaze tracking for interactive graphic display. Unlike most of the existing gaze tracking techniques, which often require assuming a static head to work well and require a cumbersome calibration process for each person our gaze tracker can perform robust and accurate gaze estimation without calibration and under rather significant head movement. This is made possible by a new gaze calibration procedure that identifies the mapping from pupil parameters to screen coordinates using the Generalized Regression Neural Networks(GRNN). With GRNN, the mapping does not have to be an analytical function and head movement is explicitly accounted for by the gaze mapping function. Futhermore, the mapping function can generalize to other individuals not used in the training. The effectiveness of our gaze tracker is demonstrated by preliminary experiments that involve gaze-contingent interactive graphic display.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.10
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• pp.2417-2426
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• 2014

Remote gaze tracking system calculates the gaze from captured images that reflect infra-red LEDs in cornea. Glint is the point that reflect infra-red LEDs to cornea. Recently, remote gaze tracking system uses a number of IR-LEDs to make the system less prone to head movement and eliminate calibration procedure. However, in some cases, some of glints are unable to spot. In this case, it is impossible to calculate gaze. This study examines patterns of glints that are difficult to detect in remote gaze tracking system. Afterward, we propose an algorithm to reconstruct positions of missing glints that are difficult to detect using other detected glints. Based on this algorithm, we increased the number of valid image frames in gaze tracking experiments, and reduce errors of gaze tracking results by correcting glint's distortion in the reconstruction phase.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3666-3671
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• 2012

We evaluate the face detection and recognition of depth image that is obtained by infrared range sensor. and Face recognition was usually focused on accuracy aspect but it is not enough to evaluate the performance in testing for real world application. In this paper, we evaluate the overall performance like accuracy, training, test speed and memory use for the well known face recognition algorithm like PCA, LDA, ICA and SVM. This experiment evaluate the good results of depth and colored depth image compatible with the colored image although the file size of depth and colored depth image is 30%~40% less than the colored image. Whereas, LDA got the good accuracy performance next to the SVM and also shows the good performance in speed and the amount of memory.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.9
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• pp.1312-1319
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• 2022

This paper defines an effectiveness index for optical continuous observation of unknown space objects and presents a range of design variables combinations that can satisfy the effectiveness index from a telescope/mount control system perspective using integrated simulation. The overall system-level simulation was implemented and the tracking performance was analyzed by considering design variables such as target position prediction and frame rate, image processing time and measurement error, target trajectory characteristics, and maneuver performance of mount gimbal. As a result of the analysis, it was confirmed that the continuous tracking performance of the optical observation system is dependent on the combination of frame rate and mount maneuver performance. In a situation where an optical observation system is designed or a similar system is implemented using COTS, an appropriate combination of parameters between design variables can be found through effectiveness analysis simulation as in this study.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.12
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• pp.1826-1834
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• 2021

In this paper, we check the possibility of continuous tracking when photographing unknown space objects in a short period of time in an optical observation system on the ground. Simulated observation data were generated for target limited to low-orbit areas. The performance index of the prediction error was set in consideration of the property of targets. Kalman Filter was applied to predict the next location of the target. A constant velocity/acceleration dynamic model was applied to the two axes of the azimuth/elevation of the unknown space object respectively. As a result of performing the Monte Carlo simulation, the maximum error ratio of the maximum nonlinear section was less than 2%, which could be determined to ensure continuous tracking. The CA model had little change in the prediction error value for each case, making it more suitable for tracking unknown space objects. This analysis could provide a foundation for determining the orbit of unknown space objects using optical observation.