• Journal of Institute of Control, Robotics and Systems
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• v.10 no.4
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• pp.325-333
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• 2004

It is investigated that the relation between the response time of DVR(Dynamic Voltage Restorer) and the possible compensation range of voltage dip by the DVR system which protects the 3-phase phase-controlled rectifier from voltage dip. As a result, the permissible range of voltage dip is presented in the 3-phase phase-controlled rectifier, and it is presented that the range of voltage dip which can be compensated according to the DVR s response time. when the DVR compensates voltage dip, Using the proposed method, the DVR s response time can be determined from the parameters of 3-phase phase-controlled rectifier and the possible compensation range of voltage dip, and it is possible to use the control system which have an appropriate speed. Therefore, the use of excessively fast device can be avoided, and the stability of the overall system is improved. Also the reliance of DVR about the 3-phase phase-controlled rectifier can be verified.

• Korean Institute of Interior Design Journal
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• v.21 no.4
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• pp.87-95
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• 2012

This study is for the analysis to which element of space the users observing the lobby at a public space pay more attention for their visual perception. It is focused on the typology process of observation characters. The subjects, in the observation process, came to be interested in the circumstantial clues for space perception and the detailed characters drawing their interest. I could analyze the observation characters of the subjects observing the space by the comprehension and typology of their observation characters. First, from the viewpoint of successive 9 times of observations, each subject observed for 0.32 second to get the visual perception in the applied space, but spent another 0.39 second for the exploration of another observation object or the space roaming. The observation character of the subjects at the lobby of the public space selected for this experiment was that they spent more time on space exploration than on concentration on a point in the space. Second, I analyzed the typology process through the time range. Since the subjects' frequency varied depending on the way to set up the time range, the necessity was proposed that the time range for the analysis of observation characters should be set up more objectively. Third, in case of analyzing the observation characters by 10-second-unit time range, the concentration in the beginning and the middle was 25%, and that in the beginning and the final 41.7%, which showed that 75% of the subjects concentrated in the beginning of the observation time when the concentration in the beginning is added to it. Fourth, the type 3 categorized as "concentration in the beginning and the middle" is the group 47.1 percent of the subjects belong to, and each subject concentrated 1.1 times in the beginning and 2.1 times in the final, which showed that the concentration in the final was 1.75 times as high as that in the beginning.

• Communications for Statistical Applications and Methods
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• v.24 no.1
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• pp.1-13
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• 2017

This manuscript summarized advances in bootstrap methods for long-range dependent time series data. The stationary linear long-memory process is briefly described, which is a target process for bootstrap methodologies on time-domain and frequency-domain in this review. We illustrate time-domain bootstrap under long-range dependence, moving or non-overlapping block bootstraps, and the autoregressive-sieve bootstrap. In particular, block bootstrap methodologies need an adjustment factor for the distribution estimation of the sample mean in contrast to applications to weak dependent time processes. However, the autoregressive-sieve bootstrap does not need any other modification for application to long-memory. The frequency domain bootstrap for Whittle estimation is provided using parametric spectral density estimates because there is no current nonparametric spectral density estimation method using a kernel function for the linear long-range dependent time process.

• JSTS:Journal of Semiconductor Technology and Science
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• v.12 no.2
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• pp.193-202
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• 2012

In this paper, we propose a new approach for compact range sensor system for real-time robot applications. Instead of using off-the-shelf camera and projector, we devise a compact system with a CMOS image-sensor and a DMD (Digital Micro-mirror Device) that yields smaller dimension ($168{\times}50{\times}60mm$) and lighter weight (500g). We also realize one chip hard-wired processing of projection of structured-light and computing the range by exploiting correspondences between CMOS images-ensor and DMD. This application-specific chip processing is implemented on an FPGA in real-time. Our range acquisition system performs 30 times faster than the same implementation in software. We also devise an efficient methodology to identify a proper light intensity to enhance the quality of range sensor and minimize the decoding error. Our experimental results show that the total-error is reduced by 16% compared to the average case.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.2
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• pp.207-214
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• 2019

This paper proposes a new feature extraction method for automatically estimating the number of target and detecting the chaff using high range resolution profile(HRRP). Feature of one-dimensional range profile is expected to be limited or missing due to lack of information according to the time. The proposed method considers the dynamic movements of targets depending on the radial velocity. The observed HRRP sequence is used to construct a time-range distribution matrix, then assuming diverse radial velocities reflect the number of target and seduction chaff launch, the proposed method utilizes the characteristic of the gradient distribution on the time-range distribution matrix image, which is validated by electromagnetic computation data and dynamic simulation.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.5
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• pp.640-648
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• 2018

Time division wireless communication in tactical MANET is attractive to deliver both high data rates and long-range coverage, and to provide scheduled QoS to mission participants. This paper is about the time synchronization issue of multi-mission USV in tactical MANET. As USV communication coverage becomes longer, the synchronization error also becomes higher; therefore, which results in link disconnection, and consequent failures of reconnection because base station cannot configure necessary parameters over long-distant terminal. We propose a range adaptive time synchronization method to compensate for synchronization errors. The issue of long-range time synchronization problem was identified during maritime communication tests, and we verified the proposed method through analyses of both indoor and outdoor test results.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.2
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• pp.117-122
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• 2000

The fractal image compression is based on the self-similarity that some area in an image is very similar to others. This compression method offers high compression ratio and fast decompression, but it has very long encoding time. To cut-off the encoding time, most researches give a restriction on domain blocks to be compared with a range block or make an effective search sequence of the domain blocks for a range block. However, most of them take much encoding time yet. In this research, we propose an algorithm that greatly reduces the encoding time by considering the coherence between range blocks. This algorithm first classifies all range blocks into some groups using the coherence between range blocks, and then searches corresponding domain blocks only for the key block of each group. If this scheme is joined in a prior work of the other fractal compression algorithm, it will give a great effectiveness to encoding time.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1582-1584
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• 2004

The microstructure, electrical, and clamping voltage characteristics of ZPCCY-based varistor ceramics were investigated in the sintering time range of 1${\sim}$3 h. Increasing sintering time promoted the densification, in which the average grain size and density are increased in the range of $11.4{\sim}16.0{\mu}m$ and $5.34{\sim}5.54g/cm^3$, respectively. The nonlinear exponent decresed in the range of 60${\sim}$26 and the leakage current increased in the range of $1.3{\sim}10.7{\mu}A$ with increase of sintering time. The clamping voltage ratio was less than 2 for ratio surge current of 10 A over sintering times.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.426-428
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• 1998

In this paper we describe a real time signal processing technique for the code correletion short range measurement sensor. Code correlation values are acquired via simple RC charging circuits within several tens of microsecond. Because the range measuring process is very fast and simple, the proposed technique is applicable to common near range targets as well as fast moving targets in real time. Some experimental results show the validity and usefulness of the proposed method.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.708-711
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• 2008

Time-of-flight(ToF) cameras deliver intensity data as well as range information of the objects of the scene. However, systematic problems during the acquisition lead to distorted values in both distance and amplitude. In this paper we propose a method to acquire reliable distance information over the entire scene correcting each information based on the other data. The amplitude image is enhanced based on the depth values and this leads depth correction especially for far pixels.