• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.37 no.7
• /
• pp.851-856
• /
• 2013

Recently, as the tactical environment has changedto one of network-centric warfare, where all components are connected through a network, much emphasis has been placed on the use of an artificial satellite for achieving high communication speeds. To provide a high-quality artificial satellite link, stabilization is very important in a platform. Previous stabilization control techniques used PI control, which is commonly used for vessels. However, for ground terminals that require a higher communication speed, the antenna should move faster to track an artificial satellite within a short period of time. Moreover, the terminals must be equipped with proper sensors and algorithms so that they can detect and compensate for external disturbances while tracking the artificial satellite. In this study, through the analysis of the dynamic model of an antenna system, a stabilization algorithm for ground terminals was proposed;this algorithm shows high isolation performance in the low-frequency range and includes $PI^2$ control.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.49 no.9
• /
• pp.347-352
• /
• 2012

In this paper, an 2D spatial-map construction for workers identification and avoidance of AGV using the detection scheme of the spatial coordinates based on stereo camera is proposed. In the proposed system, face area of a moving person is detected from a left image among the stereo image pairs by using the YCbCr color model and its center coordinates are computed by using the centroid method and then using these data, the stereo camera embedded on the mobile robot can be controlled for tracking the moving target in real-time. Moreover, using the disparity map obtained from the left and right images captured by the tracking-controlled stereo camera system and the perspective transformation between a 3-D scene and an image plane, depth map can be detected. From some experiments on AGV driving with 240 frames of the stereo images, it is analyzed that error ratio between the calculated and measured values of the worker's width is found to be very low value of 2.19% and 1.52% on average.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.2
• /
• pp.160-166
• /
• 2020

As mobile-based hardware technology develops, many kinds of applications are also being developed. In addition, there is an increasing demand to automatically check that the interface of these applications works correctly. In this paper, we describe a method for accurately detecting faulty images from applications by comparing major characteristics from input color images. For this purpose, our method first extracts major characteristics of the input image, then calculates the differences in the extracted major features, and decides if the test image is a normal image or a faulty image dissimilar to the reference image. Experiment results show that the suggested approach robustly determines similar and dissimilar images by comparing major characteristics from input color images. The suggested method is expected to be useful in many real application areas related to computer vision, like video indexing, object detection and tracking, image surveillance, and so on.

• Journal of KIISE:Computing Practices and Letters
• /
• v.14 no.6
• /
• pp.547-558
• /
• 2008

Embedded system is tightly coupled with heterogeneous layers such as application, as kernel, device driver, HAL and hardware. Embedded system is customized for the specific purpose and hardware. In addition, the product cycle is so fast that software and hardware, which are developed by several vendors, are integrated together under unstable status. Therefore, there are lots of possibilities of faults in all layers. Because embedded software developers test their codes integrated with faulty layers, they cannot confirm 'whether testing of every aspects was completed, their code was failed, or integrated software/hardware has some problems'. In this paper, we propose an embedded software interface test method and a test tool called Justitia for detecting faults and tracing causes in the interface among heterogeneous layers. The proposed technique is an automated method which improves debugging upto professional testing using an emulator for helping developer.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.48 no.3
• /
• pp.60-67
• /
• 2011

Visible light communication system transmits data by controlling light emission of LED and receives data through photo detecter, which is considered as one of strong candidates of next generation wireless communication systems. The transmission capacity of visible light communication system depends on light intensity emitted from LED, sensitivity of PD, distance between transmitter and receiver, angle of incidence at the receiver. In particular, the receiver's vertical and horizontal movement changes distance between transmitter and receiver and angle of incidence, which may degrades transmission capacity of system. In this paper, we propose an estimation algorithm of receiver's position and angle based on tracking of received light intensity for indoor visible light communication systems. The performance evaluation of proposed algorithm confirms that the estimation algorithm of receiver's position and angle is quite important for visible light communication system to improve its transmission capacity.

• Journal of Korean Library and Information Science Society
• /
• v.48 no.1
• /
• pp.77-97
• /
• 2017

With reference management tool based on web, we could understand not only impact about non-author, such as hand-on worker, educator, who are out of academia, but also trace the subject fields of readers and their status. This study by analyzing mendeley, understand what kinds of subject fields and status of readers read library and information science field articles. As a result of analyzing the status and the major of the reader, readers were distributed in the fields of business administration, education and so on, and according to the reader's major, there was a significant difference (p = .000) between the subject area of relatively read a lot. By the way, as the result of relational analysis between citation rate and numbers of mendeley readership about medeley saved articles, correlation coefficient shows 0.585, however as the result of relational analysis limiting the groups, in case of author group who tends to read the articles for citing, correlation coefficient shows 0.619. On the other hand, non-author group shows 0.384.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.4C
• /
• pp.476-483
• /
• 2009

Tracking and detecting targets by the microwave seeker is affected by the clutter reflecting from the earth's surface. In order to detect retreating targets in look-down scenario, which appear in the sidelobe clutter (SLC) region, in the microwave seeker of high pulse repetition frequency (HPRF) mode, it is necessary to understand statistical characteristics of the surface SLC. Statistical analysis of SLC has been conducted for several kinds of the surface using data obtained by the captive flight test of the microwave seeker in the HPRF mode. The probability density function (PDF) fitting is conducted for several kinds and conditions of the surface. PDFs and PDF parameters, which best describe statistical distribution of the SLC power, are estimated. By using the estimated PDFs and PDF parameters, analyses for setting the target-detection thresholds, which give a desired level of target-detection false alarm probability, are made. These analysis materials for statistical characteristics of SLC power and the target-detection threshold can be used in various fields, such as development of a target-detection method, the constant false alarm rate processing.

• The Transactions of the Korea Information Processing Society
• /
• v.7 no.11
• /
• pp.3566-3575
• /
• 2000

In this paper, we propose an simple and efficient method to estunate the camera operation by using compressed information, which is extracted diracily from MPEG2 stream without complete decoding. In the method, the motion vector is converted into approximate optical flow by using the feature of predicted frame, because the motion vector in MPEG2 video stream is not regular sequene. And they are used to estimate the camera operation, which consist of pan, and zoom by Hough transform technique. The method provided better results than the least square method for video stream of basketball and socer games. The proposed method can have a reduced computational complexity because the information is directiv abtained in compressed domain. Additionally it can be a useful technology in content-based searching and analysis of video information. Also, the estimatd cameral operationis applicable in searching or tracking objects in MPEG2 video stream without decoding.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.10 no.6
• /
• pp.512-521
• /
• 2017

Telemetry ground station use very high gain directional antenna systems that are sensitive to interference from other RF communication systems, Without appropriate interference protection, these systems could be severely impacted or even rendered useless for mission support. In ECC, we suggested ans interference analysis method between LTE-TDD system and telemetry ground station using 2.3GHz. In this paper, based on the interference analysis scenario considered in Electronic Communication Committee, We have derived mutual coexistence separation distance between telemetry ground station and LTE-TDD system(Base station, User equipment) in Spatial domain.

• Korean Journal of Remote Sensing
• /
• v.37 no.5_1
• /
• pp.1163-1175
• /
• 2021

In autonomous driving, road markings are an essential element for object tracking, path planning and they are able to provide important information for localization. This paper presents an approach to update and measure road surface markers with HD maps as well as matching using inverse perspective mapping. The IPM removes perspective effects from the vehicle's front camera image and remaps them to the 2D domain to create a bird-view region to fit with HD map regions. In addition, letters and arrows such as stop lines, crosswalks, dotted lines, and straight lines are recognized and compared to objects on the HD map to determine whether they are updated. The localization of a newly installed object can be obtained by referring to the measurement value of the surrounding object on the HD map. Therefore, we are able to obtain high accuracy update results with very low computational costs and low-cost cameras and GNSS/INS sensors alone.