• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.5
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• pp.1711-1725
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• 2014

Multi-target tracking is the main purpose of many video surveillance applications. Recently, multi-target tracking based on the particle filter method has achieved robust results by using the data association process. However, this method requires many calculations and it is inadequate for real time applications, because the number of associations exponentially increases with the number of measurements and targets. In this paper, to reduce the computational cost of the data association process, we propose a novel multi-target tracking method that excludes particle samples in the overlapped predictive region between the target to track and marginal targets. Moreover, to resolve the occlusion problem, we define an occlusion mode with the normal dynamic mode. When the targets are occluded, the mode is switched to the occlusion mode and the samples are propagated by Gaussian noise without the sampling process of the particle filter. Experimental results demonstrate the robustness of the proposed multi-target tracking method even in occlusion.

• Journal of The Korean Association For Science Education
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• v.36 no.6
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• pp.835-849
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• 2016

The purpose of the present study is to analyze the trajectory of science core school students' STEM career motivation and to examine the relationship between the trajectory patterns and students' tracks. Longitudinal STEM career motivation data with seven constructs were collected from 256 students for five semesters and the data were analyzed by using group-based trajectory modelling analysis. In order to examine the relationship between trajectory pattern groups and the tracks, chi-square tests were conducted. Based on our findings, we found that students are likely to have similar trajectory patterns in STEM career education experience and in their perception towards STEM career value. In terms of parents' support, academic self-efficacy and STEM career motivation aspects are divided into two distinctive trajectory groups ('high' and 'low' group), while two other variables, STEM career self-efficacy and STEM career interest, are divided into three trajectory groups ('moderate declining', 'high declining', 'increasing' group). Most of the trajectory groups are shown the pattern that the level of each constructs increase until their second academic year, then after that, the patterns started going down. Moreover, there are significant relationship between track and each trajectory groups. Science track and science-core track students have similar trajectory patterns. In contrast, humanities track students have different trajectory groups in some constructs. Based on these findings, we suggest that STEM career education environment should consider various patterns of students' STEM career development.

• The korean journal of orthodontics
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• v.54 no.3
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• pp.142-152
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• 2024

Objective: This retrospective cohort study aimed to assess and compare the accuracy of 3 different Invisalign^® treatment regimens in terms of variations of aligner change frequency and type of aligner material in achieving maxillary dental buccal expansion. Methods: Altogether, 120 adult patients whose treatment involved maxillary dental expansion with Invisalign^® were included. The patients were divided into 3 groups, with each group comprising 40 patients as follows: SmartTrack^® 1-week changes (ST1), SmartTrack^® 2-week changes (ST2), and EX30^® 2-week changes (EX2). The groups were assessed by comparing actual changes achieved with those prescribed by ClinCheck^®. The rates of clinically significant inaccuracies (CSI) observed for buccal expansion (≥ 0.5 mm) and buccolingual inclination (≥ 2°) during expansion were then determined. Results: In terms of expansion, the ST1 group demonstrated the highest CSI rate at all tooth levels, whereas the ST2 group had the lowest rate of CSI and the lowest mean inaccuracy for each tooth level. In terms of buccolingual inclination, the ST1 group had the highest CSI rate across all tooth levels, whereas the EX2 group had the lowest CSI rate at all tooth levels except for the canine level where the ST2 group had the lowest CSI rate. A tendency toward overexpression of buccal crown inclination, and underexpression of buccal expansion was observed at all tooth levels. Conclusions: Two-week aligner change regimens offer improved accuracy compared with 1-week aligner changes. SmartTrack^® 2-week changes were the most accurate for buccal expansion, whereas EX30^® 2-week changes were the most accurate for buccolingual inclination.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.4
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• pp.124-132
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• 2008

In this paper, a dynamical filter called the Highest Probability Data Association Filter(HPDAF) improved by adding target feature information is proposed for robust target detection and tracking in clutter. IIR contains 2-dimensional kinematic coordinate, intensity, and feature information. In data association of the HPDAF for track initiation, feature information is utilized in addition to coordinate and intensity information. The performance of the proposed HPDA algorithm is tested and compared with the conventional HPDAF algorithm for track initiation by a series of Monte Carlo simulation runs for a 3-dimensional missile-target engagement. scenario.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.4
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• pp.248-255
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• 2023

In order to implement the autonomous navigation function, it is essential to track an object within a certain radius of the ship's route. This paper proposes the Multiple Probabilistic Data Association Filter (MPDAF), which can track multiple ships by extending Probabilistic Data Association Filter (PDAF), an existing single object tracking algorithm, using radar data obtained from real marine environments. The proposed MPDAF algorithm was developed to address the problem of tracking multiple objects in a complex environment where there can be significant uncertainty in the number and identification of objects to be tracked. Using real-world radar data provided by the German aerospace center (DLR), it has been verified that the proposed algorithm can track a large number of objects with a small position error.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.1
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• pp.136-145
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• 1997

To analyzed ride quality and to predict durability in vehicle dynamics, it is essential to describe a road surface profile precisely. This paper presents a technique to generate road surface profiles in a spatial domain by using a power spectral density function. A single track power spectral density function is proposed to describe a road surface profile, which is also applicable for multi-track vehicle response analysis, The derived road surfaces are compared to ISO(International Organization for Standardization) standards and classifications, proposed by the MIRA(Motor Industry Research Association). The methodology in this paper is also proposed to generate road roughness description with a limited external data. A small amount of external curve data is combined with an internal PSD function to generate road surface roughness in a spatial domain.

• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.3
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• pp.135-148
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• 2003

In this paper we introduce the Internet-based purchase support systems using data mining and case-based reasoning (CBR). Internet Business activity that involves the end user is undergoing a significant revolution. The ability to track users browsing behavior has brought the vendor and end customer's closer than ever before. It is now possible for a vendor to personalize his product message for individual customers at massive scale. Most of former researchers, in this research arena, used data mining techniques to pursue the customer's future behavior and to improve the frequency of repurchase. The area of data mining can be defined as efficiently discovering association rules from large collections of data. However, the basic association rule-based data mining technique was not flexible. If there were no inference rules to track the customer's future behavior, association rule-based data mining systems may not present more information. To resolve this problem, we combined association rule-based data mining with CBR mechanism. CBR is used in reasoning for customer's preference searching and training through the cases. Data mining and CBR-based hybrid purchase support mechanism can reflect both association rule-based logical inference and case-based information reuse. A Web-log data gathered in the real-world Internet shopping mall is given to illustrate the quality of the proposed systems.

• Convergence Security Journal
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• v.10 no.2
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• pp.11-17
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• 2010

Recent technological advances allow us to envision a future where large numbers of low-power, inexpensive sensor devices are densely embedded in the physical environment, operating together in a wireless network. This paper considers localization for mobile sensors; localization must be invoked periodically to enable the sensors to track their location. Localizing more frequently allows the sensors to more accurately track their location in the presence of mobility. In this paper, we test and analyze the accuracy of a moving node localization by Received Signal Strength (RSS).

• Journal of Advanced Navigation Technology
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• v.12 no.1
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• pp.8-14
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• 2008

In this paper, I have presented a new approach which can track moving objects in unknown environments. This scheme is important in providing a computationally feasible alternative to complete enumeration of JPDA which is intractable. I have proved that given an artificial measurement and track's configuration, proposed scheme converges to a proper plot in a finite number of iterations. In this light, even if the performance is enhanced by using the relaxation, I also note that the difficulty in tuning the parameters of the relaxation scheme is critical aspect of this suggestion.

• Journal of Digital Convergence
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• v.17 no.5
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• pp.391-398
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• 2019

This study aimed to investigate the factors that influence the attitude toward doping and to provide useful information for developing a doping prevention program suitable for Korean athletic players. One hundred and seventy-two players who enrolled in Korea Association of Athletics Federations were participated in this study and they filled in the questionnaire about demographic factors, information on doping, perfectionism, and perceived motivational climate. Collected data were analyzed by using stepwise multiple linear regression for exploring the main factor that affect the attitude toward doping depending on field and track events. All adult players have more permissive attitude toward doping than adolescents. In track event, while players who are sensitive to coach's criticism have more permissive attitude toward doping, players who focused on personal standards have more repressive attitude toward it. These results would be useful to develop anti-doping strategy for Korean field and track players.