• KIPS Transactions on Software and Data Engineering
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• v.6 no.3
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• pp.141-148
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• 2017

The current advancement of mobile devices enables users to collect a sequence of user positions by use of the positioning technology and thus the related research regarding positioning or location information are quite arising. An individual mobility model based on positioning data and time data are already established while group mobility model is not done yet. In this research, group mobility model, an extension of individual mobility model, and the process of establishment of group mobility model will be studied. Based on the previous research of group mobility model from two individual mobility model, a group mobility model with more than two individual model has been established and the transition pattern of the model is represented by Markov chain. In consideration of real application, the computing time to establish group mobility mode from huge positioning data has been drastically improved by use of GPGPU comparing to the use of traditional multicore systems.

• Journal of Positioning, Navigation, and Timing
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• v.5 no.2
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• pp.87-96
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• 2016

The ionospheric error, which is one of many error elements considered during the Global Navigation Satellite System (GNSS) positioning, is hard to be predicted due to the influence of geomagnetic activity and irregular solar activities. Thus, the present study analyzed a change pattern in the ionosphere through Global Ionosphere Map (GIM) data for 12 years from 2003 to 2014 and a variation in the Slant Total Electron Content (STEC) between Sinuiju and Busan which was the longest range in the southeastern direction of the Korean Peninsula. The variation in the STEC verified the diurnal, annual, and solar cycle variations due to the influence of solar activity. The diurnal variation was characterized that the variation in the STEC started to increase from 6-7 am and reached the maximum at 13-14 pm followed by being decreased. The seasonal variation was characterized that the variation in the STEC was high in spring and autumn whereas it was low in summer and winter. The solar cycle variation revealed that the variation in the STEC increased during solar maximum and decreased during solar minimum. The variation in the STEC was up to 20 Total Electron Content Unit (TECU) during the solar minimum and up to 60 TECU during solar maximum.

• Journal of Positioning, Navigation, and Timing
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• v.9 no.4
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• pp.305-317
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• 2020

The navigation message is composed of the information contained in the message and the structure for transmitting this information. In order to design a navigation message, considerations in terms of message content and message structure must be elicited. For designing a Korea Positioning System (KPS) navigation message, this paper explains performance indicators in terms of message structure and message content. Most of the performance analysis of GNSS navigation messages already in operation was performed only for Time-to-first-fix-Data (TTFFD). However, in the navigation message, the message content is composed of Clock-Ephemeris Data (CED) and additional information. So, this paper proposes a new performance indicator R_(Non-CED) that can be analyzed from the viewpoint of receiving additional information along with an explanation of TTFFD focusing on the CED reception time. This paper analyze the performance in terms of message structure using these two performance indicators. The message structures used for analysis are the packetized message protocol like GPS CNAV and the packetized and fixed pattern message protocol like GPS CNAV-2. From the results, it is possible to proffer how KPS navigation messages can have better performance than GPS navigation messages. And, these two performance indicators, TTFFD and R_Non-CED, can help to design the minimum TTFF required performance of KPS navigation messages.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.47-49
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• 2022

IPS is an indoor positioning system that replaces GPS, which is less accurate due to walls and roofs inside buildings. Radio signals such as Wi-Fi are used instead of satellite signals, and complex methods are being used to increase accuracy. In this paper, we present a more efficient positioning method than before by applying high-level signals to high-accuracy fingerprint techniques. A radio map is configured with high-level signals collected by utilizing Wi-Fi APs, which are more than in the past. The suitability of use was confirmed by analyzing the pattern represented by the configured radio map for each location.

• The Mathematical Education
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• v.46 no.2 s.117
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• pp.227-237
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• 2007

This research analyzes students' response types in the creativity assessment by using pattern block, geoboard, and pantomino. 74 students from third grade to sixth grade participated in this research. 15 minutes were given to pattern block and geoboard questions. 74 students showed 393 answers in pattern block question and 590 answers in geoboard question. In pantomino, 20 minutes were given and 54 students showed 443 types of answers. The results are as follows: First, in the students' responses, tendency of using particular piece or figure, which presents conjoining in a piece selection and positioning, showed strongly. For example, usage of hexagon and trapezoid pieces were higer in pattern block and usage of L, P, and I pieces were higer in pentomino. Second, it is confirmed that creativity's subordinate factors, fluency, flexibility, and originality, are separate from each other. To illustrate, in pattern block, three students', who showed 11 types of responses in fluency, flexibility responses were each 5, 6, and 8 types. Specially, among those studenys, only one could achieve a point in originality. Third, students' response types categorized in this research could be used for a bae-data to mark grades on originality.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.8
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• pp.331-337
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• 2001

The purpose of this study is to analyze the principal causes of vibration problem and find out the method of vibration reduction in a chip-mount system. The principal causes are investigated through measurements of vibration spectrum and model parameters. Modal parameters are obtained by using an experimental model test. Based on the model parameters from experiments. a model of finite element method is formulated. The model presents effective redesign of increasing the natural frequencies in order to reduce the vibration of a chip-mount system. Further, through computer simulation for the behavior of head to be main vibration source, the best acceleration pattern of head movement can be verified to achieve effective head-positioning and reduce the vibration due to head movement.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.840-845
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• 2004

Development of the linear motors is recently required to control a high-speed and high-resolution in the high-integrated and speed process industry. This paper presents vibration analyses as well as measurement standards of the newly developed linear motors through analyzing the vibration characteristics of the advanced products. Vibration experiments are conducted for identifying vibration level during operation. They are also included in the modal test to analyze dynamic characteristics. Analytic data using Finite Element Method (FEM) are compared with the results of the modal. The FEM and experiments make it possible to understand these characteristics. Further, through computer simulation for the behavior of moving part to be vibration source, the best acceleration pattern of moving part movement can be verified to achieve effective moving part positioning and reduce the vibration due to moving part movement.

• Journal of Positioning, Navigation, and Timing
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• v.6 no.2
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• pp.43-51
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• 2017

In this study, the effect of the steering vector model mismatch due to array uncertainties on the performance of array processing was analyzed through simulation, along with the alleviation of the model mismatch effect depending on array calibration. To increase the reliability of the simulation results, the actual steering vector of the array antenna obtained by electromagnetic simulation was used along with the Jahn's channel model, which is an experimental channel model. Based on the analysis of the power spectrum for each direction, beam pattern, and the signal-to-interference-plus-noise ratio of the beamformer output, the performance deterioration of array processing due to array uncertainties was examined, and the performance improvement of array processing through array calibration was also examined.

• Fashion & Textile Research Journal
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• v.4 no.1
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• pp.11-18
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• 2002

The purpose of this study was to investigate the characteristic and composition factor of Japanese costume design. The stimulus were 25 contemporary costume design which represented the traditional image of Japanese. The main survey of questionary consisted of their evaluation of the Japanese costume image by 26 semantic differential bipolar scales and the subjects were 99 female students majoring in clothing and textiles. The data were analyzed by Factor analysis, Multidimensional Scaling Method and Regression Analysis. The major findings were as follows. As a result of design analysis, contemporary Japanese costume design which represented the traditional image had traditional form, color, texture, pattern, etc. Through factor analysis about Japanese costume image 7 factors were identified; Attractiveness, Attention, Cool and warm, Neatness, Activeness, Maturity, Classics. According to image positioning, Japanese costume design was classified by simple-decorative, soft-hard. As the result of regression analysis, The preference of Japanese costume image was related to attractive factor.

• The Journal of the Korean dental association
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• v.51 no.11
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• pp.586-594
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• 2013

The critical factors affecting the esthetics of anterior implants can be summarized as following: 1) Correct positioning of implant fixture 2) Enough amount of alveolar bone 3) Optimum volume of soft tissue. The position of implant is probably the most important factor in obtaining esthetic treatment outcome. The 3-dimensional orientation of implant is determined by the position on the alveolar ridge and its direction. Clinicians often try to mimic natural teeth when fabricating restorations. During the course of esthetic diagnosis and treatment, however, one should not forget to consider the correlation between facial pattern, lips, gingiva, alveolar ridge, as well as remaining dentition. Since anterior region is biologically unfavorable when compared with posterior region, one minor discrepancy in positioning of implant can cause esthetically undesirable treatment outcome. If one understands the biological and prosthetic meaning of implant's 3-dimensional position, he or she can achieve superior esthetic outcome in anterior region.