• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.47 no.9
• /
• pp.37-43
• /
• 2010

An Interference Cancellation Wireless Repeater transmitts directly amplified the RF signal input to extend the coverage of the base station. Such a repeater inevitably suffers from the feedback interferences due to the environment and the adaptive Interference Cancelling System(ICS) is necessary. In this paper, the Variable Stepsize Complex Sign -Sign(VSCSS) LMS algorithm for ICS is presented. The algorithm can be implemented without multiplication/division arithmetic operation so that the required logic resources can be dramatically reduced in FPGA implementation. The performance of the proposed algorithm was analyzed in comparison with CSS-LMS algorithm and the learning curves obtained from simulation showed an excellent agreement with the theorical prediction. The simulation result with ICS in fading feedback channel environment showed the performance of the proposed algorithm is competible with NLMS algorithm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.15 no.4
• /
• pp.335-344
• /
• 2004

A low phase noise EQM(Engineering Qualified Model) LO(Local Oscillator) has been developed for Ka-band satellite transponder. A VCDRO(Voltage Controlled Dielectric Resonator Oscillator) is also designed using a high impedance inverter coupled with dielectric resonator to improve the phase noise performances out of the loop bandwidth. The mechanical analysis fur housing and the thermal analysis fur circuit board are achieved. This EQM LO is applied to Ka-band satellite transponder of EQM level after environmental experiments for space application. The LO has the harmonic suppression characteristics above 52 ㏈c and requires low power consumption under 1.3 watts. The phase noise characteristics are exhibited as -101.33 ㏈c/㎐ at 10 ㎑ offset frequency and -114.33 ㏈c/㎐ at 100 ㎑ offset frequency, with the output power of 14.0 ㏈m${\pm}$0.17 ㏈ over the temperature range of -15∼＋65$^{\circ}C$.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.8A
• /
• pp.829-837
• /
• 2008

A cellular system with fixed relays is considered to be a technology that can support high data transmission service to wide areas. However, either inter-cell interference or inter-sector interference that can be produced by adding relays to the cellular system with fixed relays does not guarantee high link performance to deteriorate function, so that resource allocation for avoidance of interference is very much important. In the paper, the cellular system performance with repeater relay has been compared with the cellular system performance with relay, and cell coverage expansion at the use of relay repeater has been compared. To compare, this paper has suggested resource allocation method to avoid inter-cell interference and inter-sector interference at installation of fixed relay on the cellular system. The proposed method can allocate different frequency resources on adjacent base stations and relays to reduce interference and to expand high data transmission area, and all of frequency bands are used at each sector to elevate efficiency of the frequency when base stations and relays operate simultaneously.

• Journal of Broadcast Engineering
• /
• v.23 no.2
• /
• pp.253-260
• /
• 2018

Personalized media broadcasting services can produce their own broadcasting contents with a variety of creative themes if they have just a transmission platform and devices that can obtain videos and voices of producers without the existing expensive equipment. In this paper, we develop and implement a new broadcasting system by applying this service framework to events such as seminars or academic conferences. The devices can be installed at each conference rooms and the integrated system transmitted to users. They can watch via their multi-resolution screen, such as smart-phones, laptops, and tablet PCs. It has the advantage of being able to receive real-time streaming and VOD services as well as additional information related to the conference. It is expected to provide convenience by allowing attendees to access the information via their devices, thereby creating an impact on participation and the underlying technology for the future research.

• Proceedings of the Korea Inteligent Information System Society Conference
• /
• 2000.11a
• /
• pp.385-394
• /
• 2000

기업간 및 기업 대 정부간 문서교환의 요구를 충족시키기 위한 일원으로 기업들은 산업 표준에 따른 전자문서교환(EDI)에 많은 관심과 노력을 기울여왔으며, 국내에서는 한국 EDIFACT위원회를 중심으로 전자문서 표준화가 이루어졌다. 국내 수출업자들이 관세청에 수출신고를 위한 통관 EDI 교환은 주로 부가가치통신망(VAN) 사업자들을 통해 이루어지고 있으나 이러한 EDI 중계 서비스는 특정 VAN사업자들을 통해 EDI서비스가 독점됨에 따라 서비스 이용에 있어 값비싼 전송료 및 통신망 임차비, 잦은 통신 지연, 기업 내부 시스템과의 연계의 어려움 등으로 인하여 많은 문제점을 낳았다. 현재 이러한 전통적 방식의 EDI를 인터넷 기반으로 전환할 때 인터넷의 개방성과 저렴한 사용비용등의 장점으로 인해 비용절감과 사용자 편이성을 크게 증가시킬 것으로 기대된다. 본 연구에서는 인터넷과 웹을 이용하여 통관 EDI 중계 시스템을 개발하였다. 현재 수출을 하고자 하는 주체는 관세청에서 반드시 EDI로 수출에 관한 신고를 하여야 하는바, 본 시스템은 이러한 EDI신고를 인터넷상에서 가능하도록 한 것이다. 본 연구에서는 기존 HTML에서 진일보한 차세대 마크업 언어인 XML을 이용하였다. 본 연구에서 구축한 XML/EDI 통관시스템은 수출신고에 필요한 11개의 전자문서에 대한 XML Schema를 디자인하고, 사용자 관리, SchemaStyleTemplate 관리, XML/EDI 문서관리 XML/EDI변환, EDI 송수신 관리, 인증관리, 로그관리 등의 모듈을 지니고 있으며 개방형 EDI와 인터넷 EDI의 장점을 취합하여 설계되었다. 본 시스템은 기존의 UN/EDIFACT표준을 사용하고 있는 EDI환경과 기존 VAN 방식의 EDI 중계 시스템과 연동되며, 향후 관세청의 XML/EDI 표준 시행을 미리 대비하는 선도연구로서 자리매김이 된다. 본 연구에서는 개발된 XML/EDI 통관시스템은 향후, 서비스의 최대 걸림돌이 되어왔던 값비싼 EDI 사용료의 부담에서 벗어날 수 있게 할 것이며, 저렴한 EDI구축/운영 비용으로 전자문서교환의 활성화와 XML이 인터넷 기반의 문서유통 표준으로 자리매김할 수 있는 중요한 계기가 될 것이다.

• Korean Journal of Soil Science and Fertilizer
• /
• v.39 no.5
• /
• pp.315-320
• /
• 2006

A precision test of hydrometer method, used to determine soil texture, was conducted on selected 10 soil samples, compared to pipette method. Soil texture measurements with hydrometer method were performed with monitoring the temperature of soil suspension in settling cylinder. The temperature and its fluctuation during settling time had a range of $13^{\circ}C-28^{\circ}C$ and $0.2^{\circ}C-4.4^{\circ}C$, respectively. The difference of clay content between hydrometer and pipette method were distributed from -6.4% to 4.0%. Positive end of difference in clay content was observed at soil having very low clay content, whereas negative end at soil having high organic matter content and exchangeable cations. Except both ends, difference in clay content of soils was less than 3%, and expecially closed to 0% in soils having clay content more than 25%. The difference of sand content were distributed from -1.5% to 4.2%. Similar to clay content, positive end soil was soil sample having lowest sand content.

• Journal of Advanced Navigation Technology
• /
• v.25 no.6
• /
• pp.517-522
• /
• 2021

Optical dispersion-managed link combined with optical phase conjugation for compensating of the distorted optical signals due to chromatic dispersion and nonlinear effects, which is required to implement long-haul wavelength division multiplexed system, is proposed and assessed in viewpoint of network topology flexibility. Optical phase conjugator capable to compensate for the distorted optical signal due to nonlinear effects is placed non-midway of total transmission distance. And, in dispersion-managed link, residual dispersion per span (RDPS) of each fiber spans in former half section and latter half section with respect to optical phase conjugator are different to each other. Simulation results show when the RDPS of each fiber sections in one half section makes it's own net residual dispersion slight different from another half section's net residual dispersion, the compensation effect in the proposed link configuration is more increased.

• Journal of Korean Society of Transportation
• /
• v.19 no.1
• /
• pp.7-16
• /
• 2001

The Principle objective of this paper is to introduce a systematic approach to identifying similar container ports in Asia. For this, it analyses data on port facilities, port facility availability, port service level total container throughput, and economic index, by using Multidimentional Scaling (MDS) method. Based on the analysis it identifies five groupings of similar container ports in Asia within which Port comparison can be justifiably made, evaluates a present position of five groupings on the basis of factors used to compare container ports in Asia ; and finally proposes policy implications for operation efficiency of Pusan container port in comparison with Kaohsiung Port. The major implication is that both the Kaosuing and the Pusan port have to strengthen port facility to attract more traffic, and particularly, Pusan Port has to reinforce the number of berth, total length of berth. and yard areas.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37 no.1B
• /
• pp.39-49
• /
• 2012

With group mobility, minimizing routing overhead among intra-group nodes can be achieved by making longer the routing update period, which may lead to degradation of inter-group's routing performance and consequently the inter-group packet delivery success ratio will be decreased. To reduce the inter-group routing overhead without lowering the inter-group packet delivery success ratio, a mobility-adaptive routing update(MARU) scheme is proposed in this paper. Main idea of the proposed scheme is group-based mobility prediction and updating routing paths by selecting intermediate common relay groups.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.54 no.3
• /
• pp.39-51
• /
• 2017

Recently, looking at construction sites with either large or small scale, accidents like collision, fall, etc. occur often. These accidents lead to not only damage of human lives but also serious economic loss. In case of large scale constructions sites, safety management systems are used to reduce industrial accidents. However in construction sites with small scale, those systems cannot be applied due to problems such as lack of compatability and high installation expense. In this case, just by putting on safety gears can also reduce industrial accidents. Therefore, in this paper, a safety management systems that can be used at both large and small scale construction sites is proposed. This safety management system consists of a smart module, a repeater and a gateway, and a monitoring system. The smart module, which is detachable, is attached to a safety helmet. This module transfers the current status of the user to the monitoring system through the repeater and the gateway. The repeater transfers the data received from the smart module to the gateway, and the gateway sends the data from the repeater to the monitoring system. The monitoring system shows the user status to the safety supervisor by displaying the data - temperature, height, intensity of illumination, images - received from the smart module. The safety supervisor can monitor the user status in real-time and take immediate action in case of emergency through this monitoring system.