• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.5
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• pp.1166-1179
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• 2013

In wireless sensor network (WSN) environments, environmental noises are generated by, for example, small passing animals, crickets chirping or foliage blowing and will interfere target detection if the noises are higher than the sensor threshold value. For accurate tracking by acoustic WSNs, these environmental noises should be filtered out before initiating track. This paper presents the effect of environmental noises on target tracking and proposes a new algorithm for the noise mitigation in acoustic WSNs. We find that our noise mitigation algorithm works well even for targets with sensing range shorter than the sensor separation as well as with longer sensing ranges. It is also found that noise duration at each sensor affects the performance of the algorithm. A detection algorithm is also presented to account for the Doppler effect which is an important consideration for tracking higher-speed ground targets. For tracking, we use the weighted sensor position centroid to represent the target position measurement and use the Kalman filter (KF) for tracking.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.2
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• pp.710-726
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• 2018

This paper presents an extended particle filter to increase the accuracy and decrease the computation load of vehicle tracking. Particle filter has been the subject of extensive interest in video-based tracking which is capable of solving nonlinear and non-Gaussian problems. However, there still exist problems such as preventing unnecessary particle consumption, reducing the computational burden, and increasing the accuracy. We aim to increase the accuracy without an increase in computation load. In proposed method, we calculate the direction angle of the target vehicle. The angular difference between the direction of the target vehicle and each particle of the particle filter is observed. Particles are filtered and weighted, based on their angular difference. Particles with angular difference greater than a threshold is eliminated and the remaining are stored with greater weights in order to increase their probability for state estimation. Threshold value is very critical for performance. Thus, instead of having a constant threshold value, proposed algorithm updates it online. The first advantage of our algorithm is that it prevents the system from failures caused by insufficient amount of particles. Second advantage is to reduce the risk of using unnecessary number of particles in tracking which causes computation load. Proposed algorithm is compared against camshift, direction-based particle filter and condensation algorithms. Results show that the proposed algorithm outperforms the other methods in terms of accuracy, tracking duration and particle consumption.

• Structural Engineering and Mechanics
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• v.62 no.5
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• pp.631-642
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• 2017

Accurate actuator tracking plays an important role in real-time hybrid simulation (RTHS) to ensure accurate and reliable experimental results. Frequency-domain evaluation index (FEI) interprets actuator tracking into amplitude and phase errors thus providing a promising tool for quantitative assessment of real-time hybrid simulation results. Previous applications of FEI successfully evaluated actuator tracking over the entire duration of the tests. In this study, FEI with moving window technique is explored to provide post-experiment localized actuator tracking assessment. Both moving window with and without overlap are investigated through computational simulations. The challenge is discussed for Fourier Transform to satisfy both time domain and frequency resolution for selected length of moving window. The required data window length for accuracy is shown to depend on the natural frequency and structural nonlinearity as well as the ground motion input for both moving windows with and without overlap. Moving window without overlap shows better computational efficiency and has potential for future online evaluation. Moving window with overlap however requires much more computational efforts and is more suitable for post-experiment evaluation. Existing RTHS data from Network Earthquake Engineering Simulation (NEES) is utilized to further demonstrate the effectiveness of the proposed approaches. It is demonstrated that with proper window size, FEI with moving window techniques enable accurate localized evaluation of actuator tracking for real-time hybrid simulation.

• Journal of Digital Convergence
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• v.16 no.9
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• pp.159-172
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• 2018

This study searched and analyzed online tracking technologies. It tried to understand what to consider when establishing policies related to online tracking. Online tracking technologies were classified into 'general cookies', 'super cookies', 'fingerprinting', 'device ID tracking' and 'cross-device tracking'. Political considerations should include the layers of online tracking, the subjects of tracking technology, purpose of use, duration and storage format of information, and development of technology. The implications of this study are as follows: first, policy makers and industry should be aware that the degree of risk perceived by users may vary according to the characteristics of online tracking technology. Secondly, it is necessary to understand factors that affect the classification of online tracking technology. Finally, in the industry, preemptive measures such as building an integrated privacy system are needed to relieve anxiety of users and to build trust.

• Korean Institute of Interior Design Journal
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• v.25 no.1
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• pp.73-80
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• 2016

Street is the most fundamental component of city and place to promote diverse actions of people. Pedestrians gaze at various street environments. A visual gaze means that there are interesting elements and these elements need to be preferentially improved in the street environment improvement project. Therefore, this study aims to set up the priorities of street environment components by analyzing eye movements from a pedestrian perspective. In this study, street environment components were classified into road, street facility, building(facade) and sky and as street environment images, three "Streets of Youth" situated in Gwangbok-ro, Seomyeon and Busan University of Busan were selected. The experiment targeted 30 males and females in their twenties to forties. After setting the angle of sight through a calibration test, an eye-tracking experiment regarding the three images was conducted. Lastly, the subjects were asked to fill in questionnaires. The following three conclusions were obtained from the results of the eye-tracking experiment and the survey. First, building was the top priority of street environment components and it was followed by street facility, road and sky. Second, as components to be regarded as important, fast 'Sequence', many 'Fixation Counts' and 'Visit Counts', short 'Time to First Fixation' and long 'Fixation Duration' and 'Visit Duration' were preferred. Third, after voluntary eye movements, the subjects recognized the objects with the highest gaze frequency and the lowest gaze frequency.

• Journal of the Korea Institute of Building Construction
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• v.14 no.6
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• pp.551-559
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• 2014

Fast-tracking was developed as an optimizing method to shorten the duration of construction project in 1960's, and it introduced to Korea in 1999. Since then, many Korean companies have been used fast-tracking for getting economical benefit from shorten duration. However, there were some problems(dispute, delay and cost overrun) because of using inappropriate subcontractor management system. For this reason, previous studies suggested some management models to solve these problems. Unfortunately, however, the models have been had some doubts about reliability, objectivity and possibility of using them on real construction site. Therefore, this study suggests 3 steps of strategic subcontracting method and apply it on real fast-tracking practice(L company) to secure reliability and objectivity. Through this, the method is expected to make up the doubts of previous studies.

• Journal of the Ergonomics Society of Korea
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• v.31 no.4
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• pp.601-607
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• 2012

Objective: The aim of this study is to classify between intentional and natural blinks in vision based eye tracking system. Through implementing the classification method, we expect that the great eye tracking method will be designed which will perform well both navigation and selection interactions. Background: Currently, eye tracking is widely used in order to increase immersion and interest of user by supporting natural user interface. Even though conventional eye tracking system is well focused on navigation interaction by tracking pupil movement, there is no breakthrough selection interaction method. Method: To determine classification threshold between intentional and natural blinks, we performed experiment by capturing eye images including intentional and natural blinks from 12 subjects. By analyzing successive eye images, two features such as eye closed duration and pupil size variation after eye open were collected. Then, the classification threshold was determined by performing SVM(Support Vector Machine) training. Results: Experimental results showed that the average detection accuracy of intentional blinks was 97.4% in wearable eye tracking system environments. Also, the detecting accuracy in non-wearable camera environment was 92.9% on the basis of the above used SVM classifier. Conclusion: By combining two features using SVM, we could implement the accurate selection interaction method in vision based eye tracking system. Application: The results of this research might help to improve efficiency and usability of vision based eye tracking method by supporting reliable selection interaction scheme.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.195-200
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• 2012

We present a new algorithm which can improve the tracking performance of the double-talk robust algorithm. A detection method of the echo path change and a modification method for the update equation of the conventional adaptive filter are proposed. A duration of the high error signal to scale parameter ratio varies according to the call status and this property is used to detect the echo path change. The proposed update equation of the adaptive filter improves the tracking performance by prohibiting wrong selection of the error signal. Simulations using real speech signals and echo paths of the ITU-T G.168 standard confirmed that as compared to the conventional algorithm, the proposed algorithm improved the tracking performance by more than 4 dB.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.3
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• pp.306-312
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• 2013

Doubly fed induction generator (DFIG) systems widely used globally are highly sensitive to the grid disturbance due to the structure that the stator is connected to the grid. In the past, when a grid fault occurs in order to prevent a system, generators are separated from the grid regardless of the fault duration time. Recently, however, the grid connection standards(Grid Code)says that for the failures removed within a certain time, the generator remains operation without separating from the grid. This paper proposes a new flux tracking LVRT(Low-Voltage Ride Through) control based on system modeling equations. The validity of the proposed strategy has been demonstrated by computer simulations.

• Journal of Fashion Business
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• v.24 no.6
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• pp.63-79
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• 2020

This study analyze consumers' unconscious visual attention to color and images of internet shopping malls by using eye-tracking method. Twenty-nine participants, including 15 females and 14 males, participated. The average ages of the male and female participants were 27.3 years and 27.7 years, respectively. Ten images of five layouts (multi-composition images, single-model images, gender-composed images, videos, and moving banner images) of internet shopping malls were shown on an eye-tracker computer screen. Quantitative analyses of the eye-tracking responses were conducted. SPSS was used to analyze the descriptive characteristics and to conduct an independent-sample t-test, along with an ANOVA. The data analysis showed that the image area generally had the shortest time to first fixation (TFF), the longest duration of fixation (DOF), the highest number of fixations (NOF), and the highest numbers of revisits(NOR).Notably, visual attention towards female models was high among various images. The results can be used to improve credibility and design online shopping layout with a scientific evidence that helps consumers through their purchase decisions.