• Korean Journal of Computational Design and Engineering
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• v.19 no.3
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• pp.253-262
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• 2014

3D city model, which consisted of the 3D building models and their geospatial position and orientation, is becoming a valuable resource in virtual reality, navigation systems, civil engineering, etc. The purpose of this research is to propose the new framework to generate the 3D city model that satisfies visual and physical requirements in ground oriented simulation system. At the same time, the framework should meet the demand of the automatic creation and cost-effectiveness, which facilitates the usability of the proposed approach. To do that, I suggest the framework that leverages the mobile mapping system which automatically gathers high resolution images and supplement sensor information like position and direction of the image. And to resolve the problem from the sensor noise and a large number of the occlusions, the fusion of digital map data will be used. This paper describes the overall framework with major process and the recommended or demanded techniques for each processing step.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.4
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• pp.173-183
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• 2020

In the midst of the aging of underground facilities in urban areas and anxiety about road excavation safety accidents, the Ministry of Land, Infrastructure and Transport began to build Underground Geospatial Infomation Map from 2015 as part of the 「ground subsidence prevention measures」 and efficient use of underground spaces. So, the scope is spreading every year. The current Underground Geospatial Infomation Map information is web-based and is operated in a desktop environment, so it is true that there are some limitations in its use in a field environment such as an excavation construction site. The Underground Geospatial Infomation Map, built and operated in a web-based environment, is a large-scale 3D data. Therefore, in order to service by transmitting data to the field without delay, it is necessary to lighten the Underground Geospatial Infomation Map data. In addition, the current Underground Geospatial Infomation Map is not unified in data formats such as 3DS and COLLADA, and the coordinate system method is also different in relative coordinates and absolute coordinates. In this study, by analyzing domestic and overseas prior research and technical use cases, a mobile Underground Geospatial Infomation Map data format and a lightweight method were presented, and a technology development was conducted to create a mobile underground space integration map in the presented format. In addition, the weight reduction rate was tested by applying 3D data compression technology so that data can be transmitted quickly in the field, and technology was developed that can be used by decompressing 3D data compressed in the field. finally, it aims to supplement the technology experimentally developed in this study and conduct additional research to produce it as software that can be used in the excavation site and use it.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.3
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• pp.547-554
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• 2008

In this paper, two-stage pipelined floating-point multiplier (FP-MUL) is designed. The FP-MUL processor supports single precision multiplication for 3D graphic APIs, such as OpenGL and Direct3D and has area-efficient and low-latency architecture via saturated arithmetic, area-efficient sticky-bit generator, and flagged prefix adder. The FP-MUL has about 4-ns delay time under $0.13{\mu}m$ CMOS standard cell library and consists of about 7,500 gates. Because its maximum performance is about 250 MFLOPS, it can be applicable to mobile 3D graphics application.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.2 s.105
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• pp.178-183
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• 2006

The proposed triple-band compact chip antenna using coupled meander line and stacked meander structure for mobile RFID/PCS/WiBro. The proposed antenna is designed to operate at 900, 1,800, and 2,350 MHz, and is realized by parasitic coupled and stacked a meander line. Meander lines are using extend length of effective current path more than monopole and contribute miniaturization. The coupled meander line controls the excitations of the mobile RFID and PCS, stacked meander line controls the excitation of the WiBro. The fabricated antenna size is $10.98{\times}22.3{\times}0.98\;mm$. The resonance frequencies are 905 MHz, 1.77 GHz and 2.32 GHz. The impedance bandwidths are 24 MHz, 140 MHz and 92 MHz. The maximum gains of antenna are 0.34 dBi, 2.58 dBi and 0.4 dBi at resonance frequencies.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.11
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• pp.1672-1678
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• 2022

In this paper, the relay antenna was designed in consideration of the performance of the 28GHz band 5G mobile communication relay horn antenna, such as radiation pattern and return loss. A horn array for 5G mobile communication repeater was designed by arranging the antenna elements in phase, and the performance was analyzed. Unlike conventional WCDMA (3G) and LTE (4G), in millimeter wave band communication, high path loss occurs between transmission and reception. In the design of a 5G millimeter wave horn antenna, antenna performance such as isolation and gain between antenna elements as well as gain and bandwidth of the antenna must be additionally considered. The antenna gain of the single horn antenna (1×1) and the array horn antenna (2×4) in the 28GHz band is about 10.44d Bi and 19.58dBi, respectively, and the return loss is designed to be less than -18dB. It has proven its validity and has been shown to be suitable for application to 5G mobile communication relay system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4C
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• pp.380-387
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• 2002

In this paper, the effect of the phase noise of a local oscillator on the ACPR of a transmitter and the reception sensitivity of a receiver to meet the TIA/EIA/IS-98-D for the CDMA mobile station was analyzed. And the optimum condition for performance of the local oscillator was suggested. It was found that the phase noise level of the local oscillator in a receiver and a transmitter should be below -138.3dBc/Hz and -120dBc/Hz, respectively, at 900kHz offset. It was confirmed that the reception sensitivity and ACPR efficiency were satisfactory when the signal of the local oscillator to the down-converter of a receiver with the phase noise level of less than -138.3dBc/Hz is supplied to the up-converter of the transmitter.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.386-389
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• 2007

TV technology started from black and white TV. Color TV invented and users request more realistic TV technology. The next technology is 3DTV. For 3DTV, 3D display technology, 3D coding technology, digital mux/demux technology in broadcast and 3D video acquisition are needed. Moreover, Almost every contents now exist are 2D contents. It causes necessity to convert from 2D to 3D. This article describes 2D/3D conversion algorithm and H/W platform on FPGA board. Time difference makes 3D effect and convolution filter increased the effect. Distorted image and original image give 3D effect. The algorithm is shown on 3D display. The display device shows 3D effect by parallax barrier method and has FPGA board.

• Journal of the Korea Society of Computer and Information
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• v.12 no.4
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• pp.159-167
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• 2007

This study executed questionnaire surveys on 482 undergraduates of D-college to review the extents of spam letter messages received through the mobile phones of college students and the extents of their addiction to mobile phones. It was revealed that each college student received one or two spam letter messages on average a day. Among the received spam messages were the messages containing the contents of commodity advertisements most frequent and the surveys indicated that spam messages are hardly read. As for the addiction to mobile phones, the average score of addiction of the respondents was indicated to be 38.73 based on the full score of 100 and the number of the ones with the scores of 60 or more was 47 which is 9.75% and the ones with the scores of 70 or more was 13 which is 2.70%. Also the younger the students were, the higher were the numbers of the students included in the addictive group and the number of students from other areas included in the addictive group was high and the number of the students in 2years system included in the addictive group was higher than the number of the students in 3years system included in the addictive group.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.7
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• pp.1032-1039
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• 2022

In this paper, we designed and implemented a cavity bandpass filter combined with a cross-coupling equalizer structure to enhance Group delay for 5G mobile network repeater, which can replace the SAW (Surface Acoustic Wave) type bandwidth filter used in the existing mobile communication system. Using the 3D EM simulation tool (HFSS), the resonance frequency, the coupling coefficient between resonators, and external quality coefficient between resonators were calculated. Based on this, a 12th bandpass filter was constructed to have attenuation characteristics of more than 20dB at the edge end of both sides of the band with a metal cavity structure with a frequency band of 3500MHz to 3600MHz and bandwidth of 97.85MHz. The designed bandpass filter satisfies the group delay time requirement for the 5G mobile communication standard and the in-band and out-band frequency responses.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.3
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• pp.116-122
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• 2009

Mobile Wireless Sensor Network is an organized collection of sensor nodes and mobile sink nodes, in which the sensor node transmits the signal to the sink node. In real environment, there are many cases in which sinks have mobility caused by the people, the vehicle and etc. Since all nodes in the sensor networks have limited energy, many researches have been done in order to prolong the lifetime of the entire network. In this paper we propose Dynamic Local Update-based Routing Protocol(D-LURP) that prolong the lifetime of the entire network to efficiently maintain frequent location update of mobile sink static sensor nodes in Mobile WSNs. When the sink node moves out of the local broadcasting area the proposed D-LURP configures dynamically the local update area consisted of the new local broadcasting area and the previous dissemination node(DN) and find the path between the DN and the sink node, instead of processing a new discovering path like LURP. In this way the processing of broadcasting sink node's location information in the entire network will be omitted. and thus less energy will be consumpted. We compare the performances of the proposed scheme and existing Protocols.