Performance Analysis of Ionospheric Delay Estimation for Multi-Constellation WA-DGNSS According to the Number of Reference Stations
김동욱 Dong Uk Kim , 한덕화 Deok Hwa Han , 윤호 Ho Yun , 기창돈 Chang Don Kee , 서승우 Seung Woo Seo , 박흥원 Heung Won Park
18(4) 260-267, 2014
김동욱 Dong Uk Kim , 한덕화 Deok Hwa Han , 윤호 Ho Yun , 기창돈 Chang Don Kee , 서승우 Seung Woo Seo , 박흥원 Heung Won Park
DOI: JANT Vol.18(No.4) 260-267, 2014
For the purpose of improving the accuracy of Wide Area Differential GNSS (WA-DGNSS), estimation performance of ionospheric delay error which has a great impact on GPS error sources should be enhanced. This paper applied multi-constellation GNSS which represents GPS in USA, GLONASS in Russia, and Galileo in Europe to WA-DGNSS algorithm in order to improve performance of ionospheric delay estimation. Furthermore, we conducted simulation to analyze ionospheric delay estimation performance in Korean region by increasing the number of reference stations. Consequently, using multi-constellation GNSS to improve performance of ionospheric delay estimation is more effective than increasing the number of reference stations in spite of similar number of measurements which are in use for estimation. We expect this result can contribute to improvement for ionospheric delay estimation performance of single-frequency SBAS (Satellite Based Augmentation System) user.
|
Implementation of CWP MRT Data Processing Module for Efficient Correlating Flight Plan
김강희 Kang Hee Kim , 최상방 Sang Bang Choi
18(4) 268-277, 2014
김강희 Kang Hee Kim , 최상방 Sang Bang Choi
DOI: JANT Vol.18(No.4) 268-277, 2014
It is very important to correlate flight plan for safe and prompt ATC(air traffic control) operation. In this paper, we design CWP(controller working position) MRT(multi radar tracking) processing module to achieve improvement of overall ATC automation system’s performance by minimizing network traffic overload when correlating MRT with flight plan. This implemented module can guarantee efficiency and safety of ATC automation system by applying distributed correlated manner, and reduce network usage by using encoded flight plan correlated MRT data format. We found that this module has 8.54~12.11% lower network usage and 8.37~11.27% higher network traffic fairness than the module using standalone manner.
|
A Design and Implementation of an ADS-B Monitoring System Capable of Displaying Air Traffic Situation
송인성 In Seong Song , 장은미 Eun Mee Jang , 윤완오 Wan Oh Yoon , 최상방 Sang Bang Choi
18(4) 278-287, 2014
송인성 In Seong Song , 장은미 Eun Mee Jang , 윤완오 Wan Oh Yoon , 최상방 Sang Bang Choi
DOI: JANT Vol.18(No.4) 278-287, 2014
ADS-B is a newly developed air surveillance technology to address the consistently increasing air traffic needs. ADS-B attracts attention for replacing or complementing a conventional radar since ADS-B can provide more accurate position information with a shorter interval when compared to the radar. However, as ADS-B uses wireless data links on exchanging information between an aircraft and a ground ADS-B system, and uses protocols without integrity support on exchanging information within the ground ADS-B system, a system which can monitor the operational status of an ADS-B system is essential. In this work, we design and implement an ADS-B monitoring system capable of displaying air traffic situation that can show the comprehensive air traffic situation while monitoring the operational status of the ADS-B system. The implemented ADS-B monitoring system has been verified with a configured ADS-B ground system by displaying ADS-B surveillance data, radar surveillance data, and flight information after receiving live surveillance data of in flight aircrafts, and virtual flight information data.
|
Consideration on Taean Airport Curved Approach Using the Simulator
구본수 Bon Soo Koo , 전향식 Hyang Sig Jun , 정명숙 Myeong Sook Jung , 박수복 Soo Bog Park , 홍승범 Seung Beom Hong , 홍교영 Gyo Young Hong
18(4) 288-295, 2014
구본수 Bon Soo Koo , 전향식 Hyang Sig Jun , 정명숙 Myeong Sook Jung , 박수복 Soo Bog Park , 홍승범 Seung Beom Hong , 홍교영 Gyo Young Hong
DOI: JANT Vol.18(No.4) 288-295, 2014
Current ILS is difficult for the many aircraft to access to the system at the same time because of it`s system. And the equipments should be installed at the direction of every runway. Also, There is limitation that landing procedures must be have of only ILS single course when the aircraft land on the ground. hereupon, The more air traffic exist, the longer delay time of flight be. GBAS using the GNSS has been developed to overcome those limitations. Before flight test in Teean airport, this paper compares the taean approach procedure and curved approach procedure by using the simulator. Comparison study shows that curved approach procedure takes less flight time, low fuel consumpsion and make it possible to avoid noise airspace more than original procedure.
|
A Study for Method of Curved Approach Using the GPS to Apply VFR Airport
주요한 Yo Han Ju , 전향식 Hyang Sig Jun , 정명숙 Myeong Sook Jung , 박수복 Soo Bog Park , 홍승범 Seung Beom Hong , 홍교영 Gyo Young Hong
18(4) 296-303, 2014
주요한 Yo Han Ju , 전향식 Hyang Sig Jun , 정명숙 Myeong Sook Jung , 박수복 Soo Bog Park , 홍승범 Seung Beom Hong , 홍교영 Gyo Young Hong
DOI: JANT Vol.18(No.4) 296-303, 2014
Recently a system is being required to replace ILS due to increasing air traffic. In this paper, Curved approach is applied to an airport where ILS approach cannot be applied due to its geographical condition and restricted aerospace condition, and verified by flight test. After analysing conditions of Tae-an airfield of Hanseo University with virtual ILS approach, airfield applicability was evaluated by Curved approach using by GPS. Normally simulation is performed after establishing approach procedure using electric map, but recently verification is being performed by flight test without simulation because accuracy and reliability are increased. In this paper, established procedure is verified modified by flight test with Pilot Test and Auto Pilot test and controllability and passenger``s stability were also checked.
|
Automatic Defect Detection and Classification Using PCA and QDA in Aircraft Composite Materials
김영범 Young Bum Kim , 신덕하 Duk Ha Shin , 황승준 Seung Jun Hwang , 백중환 Joong Hwan Baek
18(4) 304-311, 2014
김영범 Young Bum Kim , 신덕하 Duk Ha Shin , 황승준 Seung Jun Hwang , 백중환 Joong Hwan Baek
DOI: JANT Vol.18(No.4) 304-311, 2014
In this paper, we propose a ultra sound inspection technique for automatic defect detection and classification in aircraft composite materials. Using local maximum values of ultra sound wave, we choose peak values for defect detection. Distance data among peak values are used to construct histogram and to determine surface and back-wall echo from the floor of composite materials. C-scan image is then composed through this method. A threshold value is determined by average and variance of the peak values, and defects are detected by the values. PCA(principal component analysis) and QDA(quadratic discriminant analysis) are carried out to classify the types of defects. In PCA, 512 dimensional data are converted into 30 PCs(Principal Components), which is 99% of total variances. Computational cost and misclassification rate are reduced by limiting the number of PCs. A decision boundary equation is obtained by QDA, and defects are classified by the equation. Experimental result shows that our proposed method is able to detect and classify the defects automatically.
|
Development of Software GPS Receiver for GEO Satellites Using Weak Signal Receiver Algorithm
김종원 Chong Won Kim , 김강호 Kang Ho Kim , 기창돈 Chang Don Kee
18(4) 312-318, 2014
김종원 Chong Won Kim , 김강호 Kang Ho Kim , 기창돈 Chang Don Kee
DOI: JANT Vol.18(No.4) 312-318, 2014
The altitudes of GEO satellites are higher than those of GPS satellites. Therefore the visibility and the received power of GPS signals are totally different from those of the users near the Earth’s surface. In this study, we analyzed the visibility of GPS signals received on GEO satellites. And we also developed a software GPS receiver that works on GEO satellites using CCMDB algorithm which is a weak signal receiver algorithm. GPS signals received on a GEO satellite are generated by a commercial hardware GPS simulator and used for the verification of the developed software GPS receiver. The mean 3D position and velocity error are calculated as 165.636 m and 0.5081 m/s.
|
Implementation of the Web-Based K-LOSA Program for the Safety Observation in Normal Operation
최연철 Youn Chul Choi , 홍승범 Seung Beom Hong
18(4) 319-324, 2014
최연철 Youn Chul Choi , 홍승범 Seung Beom Hong
DOI: JANT Vol.18(No.4) 319-324, 2014
Line operation safety audit (LOSA) is the proactive data collection system to capture the accident and serious incident caused by flight crew and is the safety management program for collecting threat error management (TEM) and crew resource management (CRM) during normal operations. The typically LOSA is written by hand, manages and archives the LOSA Observation Worksheet. But, this method is not easy to archive and ensure confidentiality of the LOSA worksheets. As we implemented the K-LOSA of the web-document type instead of the existing LOSA archive method and change the TEM category code. we yields to archive the efficient data management and confidentiality. In this paper, we introduce the LOSA and to configure the K-LOSA program.
|
A Design and Implementation of a Remote Status Monitor and Control System for an ADS-B System
장은미 Eun Mee Jang , 송인성 In Seong Song , 윤완오 Wan Oh Yoon , 최상방 Sang Bang Choi , 최상방 Sang Bang Choi
18(4) 325-333, 2014
장은미 Eun Mee Jang , 송인성 In Seong Song , 윤완오 Wan Oh Yoon , 최상방 Sang Bang Choi , 최상방 Sang Bang Choi
DOI: JANT Vol.18(No.4) 325-333, 2014
An ADS-B system, which is a critical technology in surveillance area of the CNS/ATM, can replace or compensate a conventional radar based surveillance system through the communications among aircrafts. An ADS-B ground system which is to use the ADS-B on the ground air traffic management system consists of various subsystem devices such as ground stations that communicate with the aircrafts, and ADS-B/TIS-B/FIS-B servers. The ADS-B ground system has a form of distributed system and is interconnected through the network. Therefore, a system which can monitor and control the status of the multiple subsystem devices of the ADS-B ground system is essential. In this paper, we designed and implemented a remote status monitor and control system for the ADS-B system that can monitor and control the subsystem devices of the ADS-B system in remote place via SNMP protocol.
|
Case Analysis of the Aviation Accident, Incident During the Last 10 Years Using the ECCAIRS 5 Data
홍승범 Seung Beom Hong , 최연철 Youn Chul Choi , 홍승범 Seung Beom Hong , 최연철 Youn Chul Choi
18(4) 334-340, 2014
홍승범 Seung Beom Hong , 최연철 Youn Chul Choi , 홍승범 Seung Beom Hong , 최연철 Youn Chul Choi
DOI: JANT Vol.18(No.4) 334-340, 2014
Recently, in an effort to decrease aviation accident worldwide, there has not been any significant decline of the aviation accident rate. Therefore, in the international society, it is more focused on removing risk factors based on data collected and analyzed, in order to improve the aviation safety. This paper introduces on the characteristic of ECCAIRS 5 which become the standard for the worldwide aviation safety reporting and data exchange system. Also, using domestic aviation accident data collected during last 10 years(from 2003 to 2012), we analyze the distribution of the aviation accidents/incidents, annual and monthly aviation accident rate, flight phase, and occurrence category according aircraft type(Fixed/Rotary wing). The analyzation regarding the tendency of aviation accident/serious incident will give the direction to approach the quantitative safety management.
|
Design and Fabrication of Wideband DFD Phase Correlator for 6.0~18.0 GHz Frequency
최원 Won Choi , 구경헌 Kyung Heon Koo , 최원 Won Choi , 구경헌 Kyung Heon Koo
18(4) 341-346, 2014
최원 Won Choi , 구경헌 Kyung Heon Koo , 최원 Won Choi , 구경헌 Kyung Heon Koo
DOI: JANT Vol.18(No.4) 341-346, 2014
This paper has presented the design and fabrication of phase correlator for wideband digital frequency discriminator (DFD) operating over the 6.0 to 18.0 GHz frequency range. Fabricated DFD phase correlator has been measured I or Q output signal, and analyzed frequency discrimination error. The operation of the proposed mixer type correlator has been analyzed by deriving some analytic equations. To design the phase correlator, this paper has modeled and simulated IQ mixer and 8-way power divider by using RF simulation tool. Designed phase correlator has fabricated and measured. The phase error and frequency discrimination error have been presented using by measured I and Q output signal. Over the 6.0 ~ 18.0 GHz range, the root mean square(RMS) phase error is 4.81°, RMS and frequency discrimination error is 1.49 MHz, RMS.
|
A Call Admission Control Using Markovian Queueing Model for Multi-services Cognitive Radio Networks
이진이 Jin Yi Lee , 이진이 Jin Yi Lee
18(4) 347-352, 2014
이진이 Jin Yi Lee , 이진이 Jin Yi Lee
DOI: JANT Vol.18(No.4) 347-352, 2014
In this paper, we propose a Markovian queueing model(M/M/1)-based call admission control to reduce forced terminating rate of non-real secondary user`s call for Multi-services Cognitive Radio Networks. A existing control has a problem that the forced terminating rate increases because of adopting a policy of spectrum priority allocation to real calls. In our scheme the rate can be reduced as the call that has no useful spectrum waits in a queue until getting an available spectrum. Our scheme use a neural-net based prediction of primary user`s reappearance. Through the simulation, we analysis the call forced terminating rate, access delay and spectrum utilization efficiency, and then show that our scheme can more reduce the forced terminating rate of the call, compared to that of the existing algorithm.
|
DNP3 Protocol Security and Attack Detection Method
권성문 Sung Moon Kwon , 유형욱 Hyung Uk Yoo , 이상하 Sang Ha Lee , 손태식 Tae Shik Shon , 권성문 Sung Moon Kwon , 유형욱 Hyung Uk Yoo , 이상하 Sang Ha Lee , 손태식 Tae Shik Shon
18(4) 353-358, 2014
권성문 Sung Moon Kwon , 유형욱 Hyung Uk Yoo , 이상하 Sang Ha Lee , 손태식 Tae Shik Shon , 권성문 Sung Moon Kwon , 유형욱 Hyung Uk Yoo , 이상하 Sang Ha Lee , 손태식 Tae Shik Shon
DOI: JANT Vol.18(No.4) 353-358, 2014
In the past, security on control system was guaranteed by isolation of control system networks from external networks. However as devices of the control systems became more various and interaction between the devices became necessary, effective management system for such network emerged and this triggered connection between control system networks and external system networks. This made management of control system easier but also made control system exposed to various cyber attack threats, Therefore researches on appending security measures on each protocols are in progress. This paper focused on DNP(distributed network protocol)3 protocol which is used for communication between control center and substations. It describes characteristics of DNP3 protocol and research on adding security elements to the protocol. It also analyzed known vulnerabilities of DNP3 protocol and proposed data mining methodology for detecting such vulnerabilities.
|
An Unequal Divider with Enhanced Physical Isolation Between Output Ports
김영 Young Kim , 윤영철 Young Chul Yoon , 김영 Young Kim , 윤영철 Young Chul Yoon
18(4) 359-363, 2014
김영 Young Kim , 윤영철 Young Chul Yoon , 김영 Young Kim , 윤영철 Young Chul Yoon
DOI: JANT Vol.18(No.4) 359-363, 2014
This paper presents the design and performance of an unequal divider with physical separation and electrical isolation. This divider has a series 18 Ω resistor and 0.7 pF capacitor circuit between two quarter-wave transmission lines at half phase angle from input terminal. This design method was improved a physical isolation between output ports and easy connected other circuit because of unnecessary of extra transmission line. To show the validity of the unequal divider with complex isolation components, a 4:1 ratio unequal divider was designed and measured at center frequency of 2 GHz. The measured divider performances have the return loss of 17 dB, insertion loss of 1.5 dB and 7.7 dB, and isolation of 18 dB. Its performance is in good agreement with the simulated results.
|
A New Manufacturing Technology and Characteristics of Trench Gate MOSFET
백종무 Jong Mu Baek , 조문택 Moon Taek Cho , 나승권 Seung Kwon Na , 백종무 Jong Mu Baek , 조문택 Moon Taek Cho , 나승권 Seung Kwon Na
18(4) 364-370, 2014
백종무 Jong Mu Baek , 조문택 Moon Taek Cho , 나승권 Seung Kwon Na , 백종무 Jong Mu Baek , 조문택 Moon Taek Cho , 나승권 Seung Kwon Na
DOI: JANT Vol.18(No.4) 364-370, 2014
In this paper, high reliable trench formation technique and a novel fabrication techniques for trench gate MOSFET is proposed which is a key to expend application of power MOSFET in the future. Trench structure has been employed device to improve Ron characteristics by shrinkage cell pitch size in DMOSFET and to isolate power device part from another CMOS device part in some power integrated circuit. A new process method for fabricating very high density trench MOSFETs using mask layers with oxide spacers and self-align technique is realized. This technique reduces the process steps, trench width and source and p=body region with a resulting increase in cell density and current driving capability and decrease in on resistance.
|
Analysis of TE Scattering by a Resistive Strip Grating Over a Grounded Dielectric Layer Using Point Matching Method
윤의중 Uei Joong Yoon , 윤의중 Uei Joong Yoon
18(4) 371-375, 2014
윤의중 Uei Joong Yoon , 윤의중 Uei Joong Yoon
DOI: JANT Vol.18(No.4) 371-375, 2014
In this paper, the solutions of TE(transverse electric) scattering problems by a resistive strip grating over a grounded dielectric layer are analyzed by applying the PMM(point matching method) known as a numerical method of electromagnetic fileld. The boundary conditions are applied to obtain the unknown field coefficients and the resistive boundary condition is used for the relationship between the tangential magnetic field and the induced surface current density on the resistive strip. The induced surface current density of resistive strip is obtained by difference of the up and down of the magnetic field in two boundary areas of the resistive strip. The numerical results for reflected power of zeroth order mode analyzed by according as the resistivity, the width and spacing of resistive strip, the relative permittivity and thickness of dielectric layer, and incident angles. The numerical results shown in good agreement compared to those of the existing papers using FGMM(fourier galerkin moment method).
|
Compact and Broadband L-shaped Slot Antenna
장민규 Min Gyu Jang , 이영순 Young Soon Lee , 장민규 Min Gyu Jang , 이영순 Young Soon Lee
18(4) 376-380, 2014
장민규 Min Gyu Jang , 이영순 Young Soon Lee , 장민규 Min Gyu Jang , 이영순 Young Soon Lee
DOI: JANT Vol.18(No.4) 376-380, 2014
In the present study, oblique L-shaped monopole slot antenna with broadband characteristic is newly proposed. For bandwidth enhancement as well as size reduction, L-shaped slot with two open-terminations on the ground edge is used. The lower part of L-shaped slot comprises oblique form for bandwidth enhancement in low frequency band, whereas its higher part comprise tapered form for its enhancement in high frequency band. The short-circuit terminated microstrip line which is generally known to be more useful for bandwidth enhancement than open-circuit termination is used. The measured impedance bandwidth(-10 dB) and gain of the fabricated antenna have been observed to be 4.72 GHz (2.28~7 GHz) and more than 3dBi over the passband respectively.
|
A Study on the Variation of Electric Contact Resistance Due to Change in Contact Force in a Tin-plated Connector
유환신 Hwan Shin Yu , 오만진 Man Jin Oh , 박형배 Hyung Bae Park , 유환신 Hwan Shin Yu , 오만진 Man Jin Oh , 박형배 Hyung Bae Park
18(4) 381-386, 2014
유환신 Hwan Shin Yu , 오만진 Man Jin Oh , 박형배 Hyung Bae Park , 유환신 Hwan Shin Yu , 오만진 Man Jin Oh , 박형배 Hyung Bae Park
DOI: JANT Vol.18(No.4) 381-386, 2014
In order to investigate the effect of contact load, which is one of the fretting corrosion factors affecting the electric connector, a coupled fretting corrosion specimens were prepared using a tin-plated brass coupon with a thickness of 3 μm. Electric resistance of the contact was measured during the fretting corrosion test period. There was increase in resistance with fretting cycles. The change in resistance can be classified by 3 stages. The first stage exhibited low and stable resistance. Second stage showed steady increment of the resistance and third stage showed very high and intermittent resistance. The relationship between the failure cycle (Nf) and contact force (P) can be drawn as; It is possible to draw the prediction equation for the failure cycle of the electric connector corresponding to the very high and intermittent resistance under various environment conditions through the fretting tests under various conditions such as load, displacement, temperature.
|
Shadow Removal Based on Chromaticity and Entropy for Efficient Moving Object Tracking
박기홍 Ki Hong Park , 박기홍 Ki Hong Park
18(4) 387-392, 2014
박기홍 Ki Hong Park , 박기홍 Ki Hong Park
DOI: JANT Vol.18(No.4) 387-392, 2014
Recently, various research for intelligent video surveillance system have been proposed, but the existing monitoring systems are inefficient because all of situational awareness is judged by the human. In this paper, shadow removal based moving object tracking method is proposed using the chromaticity and entropy image. The background subtraction model, effective in the context awareness environment, has been applied for moving object detection. After detecting the region of moving object, the shadow candidate region has been estimated and removed by RGB based chromaticity and minimum cross entropy images. For the validity of the proposed method, the highway video is used to experiment. Some experiments are conducted so as to verify the proposed method, and as a result, shadow removal and moving object tracking are well performed.
|
Study of Multi-Charging System Using M2M for Efficient Electric Vehicle Charging
홍록지 Rok Ji Hong , 문일영 Il Young Moon , 홍록지 Rok Ji Hong , 문일영 Il Young Moon
18(4) 393-400, 2014
홍록지 Rok Ji Hong , 문일영 Il Young Moon , 홍록지 Rok Ji Hong , 문일영 Il Young Moon
DOI: JANT Vol.18(No.4) 393-400, 2014
With developed countries, nationally the supply and development of electric vehicle(EV) has been going at a rapid pace. Now, the charger specifications, charging methods and standardization of communication protocols is going in each country and a lot of company are involved in the business about those. To popularize it as existing car, it is required to build the network and infrastructure which is proper for domestic environment. It should also need to be able to develop standardized protocols can be beyond the construction of the protocol of the upper stage server and charger, and is used in a residential environment actually applied to related industries . Therefore, in this paper, we propose a home network model of EV that raised the need for a study of the charging system for EV, using M2M technology and multi-charging system tailored to the residential environment of our country.
|
Processing Method of Mass Small File Using Hadoop Platform
김창복 Chang Bok Kim , 정재필 Jae Pil Chung , 김창복 Chang Bok Kim , 정재필 Jae Pil Chung
18(4) 401-408, 2014
김창복 Chang Bok Kim , 정재필 Jae Pil Chung , 김창복 Chang Bok Kim , 정재필 Jae Pil Chung
DOI: JANT Vol.18(No.4) 401-408, 2014
Hadoop is composed with MapReduce programming model for distributed processing and HDFS distributed file system. Hadoop is suitable framework for big data processing, but processing of mass small files have many problems. The processing of mass small file in hadoop have problems to created one mapper per one file, and it have problems to needed many memory for store of meta information of file. This paper have comparison evaluation processing method of mass small file with various method in hadoop platform. The processing of general compression format is inadequate because of processing by one mapper regardless of data size. The processing of sequence and hadoop archive file is removed memory problem of namenode by compress and combine of small file. Hadoop archive file is faster then sequence file about combine time of small file. The processing using CombineFileInputFormat class is needed not combine of small file, and it have similar speed big data processing method.
|