• International Journal of Advanced Culture Technology
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• v.7 no.4
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• pp.313-320
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• 2019

Nowadays, as the availability of tiny, low-cost microcomputer increases at a high level, mobile robots are experiencing remarkable enhancements in hardware design, software performance, and connectivity advancements. In order to control Turtlebot 2, several algorithms have been developed using the Robot Operating System(ROS). However, ROS requires to be run on a high-cost computer which increases the hardware cost and the power consumption to the robot. Therefore, design an algorithm based on low-cost hardware is the most innovative way to reduce the unnecessary costs of the hardware, to increase the performance, and to decrease the power consumed by the computer on the robot. In this paper, we present a path-finding algorithm for TurtleBot 2 based on low-cost hardware. We implemented the algorithm using Raspberry pi, Windows 10 IoT core, and RPLIDAR A2. Firstly, we used Raspberry pi as the alternative to the computer employed to handle ROS and to control the robot. Raspberry pi has the advantages of reducing the hardware cost and the energy consumed by the computer on the robot. Secondly, using RPLIDAR A2 and Windows 10 IoT core which is running on Raspberry pi, we implemented the path-finding algorithm which allows TurtleBot 2 to navigate from the starting point to the destination using the map of the area. In addition, we used C# and Universal Windows Platform to implement the proposed algorithm.

• The Journal of the Korea Contents Association
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• v.5 no.5
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• pp.172-181
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• 2005

The latest attack type against network traffic appeared by worm and bot that are advanced in DDoS. It is difficult to detect them because they are diversified, intelligent, concealed and automated. The exisiting traffic analysis method using SNMP has a vulnerable problem; it considers normal P2P and other application program to be harmful traffic. It also has limitation that does not analyze advanced programs such as worm and bot to harmful traffic. Therefore, we analyzed harmful traffic out Protocol and Port analysis. We also classified traffic by protocol, well-known port, P2P port, existing attack port, and specification port, apply singularity weight to detect, and analyze attack availability. As a result of simulation, it is proved that it can effectively detect P2P application, worm, bot, and DDoS attack.

• ETRI Journal
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• v.45 no.4
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• pp.713-723
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• 2023

Game bots are illegal programs that facilitate account growth and goods acquisition through continuous and automatic play. Early detection is required to minimize the damage caused by evolving game bots. In this study, we propose a game bot detection method based on action time intervals (ATIs). We observe the actions of the bots in a game and identify the most frequently occurring actions. We extract the frequency, ATI average, and ATI standard deviation for each identified action, which is to used as machine learning features. Furthermore, we measure the performance using actual logs of the Aion game to verify the validity of the proposed method. The accuracy and precision of the proposed method are 97% and 100%, respectively. Results show that the game bots can be detected early because the proposed method performs well using only data from a single day, which shows similar performance with those proposed in a previous study using the same dataset. The detection performance of the model is maintained even after 2 months of training without any revision process.

• 도로교통
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• s.70
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• pp.75-79
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• 1997

• Journal of the Chungcheong Mathematical Society
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• v.7 no.1
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• pp.33-39
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• 1994

The purpose of this paper prove the following property; Suppose A has many units (local global ring) and |A/m| > 5 for every maximal ideal $m{\subseteq}A$. Let(E, q) ${\in}$ Q(A) and $E=E_1{\bot}{\cdots}{\bot}E_t$ be an orthogonl decomposition of E with $t{\geq}2$ and $rk(E_i){\geq}1$, for $i=1,{\cdots},t$. Let $x{\in}E$ be a primitive vector. Then there exists ${\sigma}{\in}O(q)$ such that ${\sigma}(x)$ is transversal to this decomposition.

• The Journal of Korean Academy of Sensory Integration
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• v.7 no.2
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• pp.37-47
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• 2009

Objective : The aim of this study is to verify the effects of group sensory integrative intervention on praxis and socialization for school-aged children with sensory integration disorder. Method : The subjects are five children aged between 7 and 13 with sensory integration disorder. All children had participated in 26 sessions of group sensory integrative intervention. The Bruininks-Oseretasky Test of Motor Proficiency(BOT-2) and The Scale for Basic Socialized Function were used so as to evaluate the praxis and socialization. One group pretest-posttest design was used to verify the effect of group sensory integration(SI) intervention. The statistical difference between before and after the group SI intervention in the BOT-2, Scale for basic socialized function is tested by the Wilcoxon matched-pairs signed ranks test. Results : There is a significant difference in BOT-2(Z=-2.023, p=.043) and Scale for basic socialized function(Z=-2.023, p=.043) scores comparing pre-intervention with post-intervention. Conclusions : The results of this study showed that the group sensory integration intervention is effective in improving the praxis and socialization for school-aged children. However, it is difficult to generalize the conclusion because the number of subjects was limited and the environmental confounding factors had not been considered. Therefore, in the future research, it should supplement the aspect these limitations before applying the sensory integration intervention in order to suggest standard criteria for norm data.

• The Journal of the Korean dental association
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• v.56 no.2
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• pp.94-102
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• 2018

The present study was conducted to assess the growth changes of human chin in childhood and adolescence at various stages of skeletal maturation using metallic implant installed in mandibular body. Lateral cephalographs including 23 subjects (9 males and 14 females) between 7-18 years old were used, which had been taken at University of California in San Francisco and kept at University of the Pacific. Three lateral cephalographs were chosen for each subject according to CVM (Cervical Vertebral Maturation) method (CVM stage 1 to 2, CVM stage 3 to 4, and CVM stage 5 to 6) which assess the extent of the skeletal maturation using the second, third, and fourth cervical vertebrae. V-ceph was used in order to mark the 8 landmarks (S, N, A, B, Pog, Me, Go, Imp) on lateral cephalographs and obtain 8 angular and linear measurements(ANB, SNPog, SN-GoMe, Imp-B, Imp-Pog, B-Pog//GoMe, $GoMe{\bot}B$, $GoMe{\bot}Pog$). Among 8 measurements, ANB, SNPog, SN-GoMe, B-Pog//GoMe, $GoMe{\bot}B$ showed statistically significant growth changes at various stages of skeletal maturation according to CVM method, while there were no significant differences on Imp-B, Imp-Pog, $GoMe{\bot}Pog$. The results suggest that the increasing prominence of human chin is greatly influenced by the vertical growth of B point area, in addition to the change and growth in chin and mandible proper.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.257-261
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• 2000

The value of I$_c$(critical current) in HTS (High Temperature Superconductor) tape has a great influence on B${\bot}$(vertical field). Therefore, in shape design of field coil for the HTSG(High Temperature Superconducting Generator), a method to reduce the B${\bot}$ should be considered in order to maintain the stability and substantial improvement on the performance. On the basis of the magnetic field analysis, this paper deals with various field coil shape according to the iron plate to obtain small B${\bot}$ by using Biot-Savart's law, image method and 2D FEA(2 Dimensional Finite Element Analysis) considering the stress condition of HTS. Moreover, the analysis is verified by comparison with experimental results. And also this paper presents the advanced model by using 3D FEA, in which flux density at armature is calculated in 5kVA class HTSG.

• Korea Information Processing Society Review
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• v.30 no.2
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• pp.39-44
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• 2023

• The Journal of Korean Academy of Sensory Integration
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• v.17 no.3
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• pp.14-25
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• 2019

Objective : This study aims to verify the content validity and inter-rater reliability of the Korean version of the Peabody Developmental Motor Scale 2 (PDMS-2) and to identify the concurrent validity by comparing it with the Korean version of the Bruininks-Oseretsky Test of Motor Proficiency-2 (BOT-2). Methods : PDMS-2 was translated by the researcher and an eighth-year clinical occupational therapist. The content consistency of the Korean version of the PDMS-2 was verified by three professors with experience using it. After the verification of the content consistency of the PDMS-2 by the five clinical occupational therapists and the additional revision, the Korean version of the PDMS-2 was completed. The researcher and another occupational therapist evaluated the Korean version of PDMS-2 in 50 children and measured the inter-rater reliability. Concurrent validity was measured by comparing the results of the Korean version of PDMS-2 and Korean version of BOT-2. Results : The content consistency test showed overall agreement of mean 3.45, and the content understanding test showed a high level of understanding of mean 3.69. The inter-rater reliability and concurrent validity of the Korean version of the PDMS-2 showed a statistically significant correlation. Conclusion : The Korean version of the PDMS-2 showed high content understanding, reliability, and validity. It can assist clinicians and researchers who work in fields related to child treatment or development.