Development and Performance Test of a Spherical Reaction Wheel Actuator with Magnetic Levitation
김대관 Dae Kwan Kim , 윤형주 Hyung Joo Yoon , 김용복 Yong Bok Kim , 강우용 Woo Yong Kang , 최홍택 Hong Taek Choi
16(5) 731-737, 2012
김대관 Dae Kwan Kim , 윤형주 Hyung Joo Yoon , 김용복 Yong Bok Kim , 강우용 Woo Yong Kang , 최홍택 Hong Taek Choi
DOI: JANT Vol.16(No.5) 731-737, 2012
In the present study, a feasibility study on an innovative satellite attitude control actuator is performed. The actuator is specially designed to generate the reaction torque in an arbitrary axis, so that a satellite attitude can be controlled by using itself. It consists of a spherical flywheel and electromagnets for levitation and rotation control of the ball. As the earlier study, a rotating performance test on the spherical actuator is conducted in a single rotating axis and vertical levitation condition. From the test results, it can be confirmed that the maximum speed and torque of the innovative device are 7,200rpm and 0.7Nm, respectively. Using a velocity-voltage characteristic curve of the spherical motor, an open-loop control (V/f constant control) is performed, and the test results show excellent control performance in acceleration and deceleration phases.
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Performance Improvement of Azimuth Estimation in Low Cost MEMS IMU based INS/GPS Integrated Navigation System
천세범 Se Bum Chun , 허문범 Moon Beom Heo
16(5) 738-743, 2012
천세범 Se Bum Chun , 허문범 Moon Beom Heo
DOI: JANT Vol.16(No.5) 738-743, 2012
Kalman filter is generally used in INS/GPS integrated navigation filter. However, the INS with low performance inertia sensor can not find accurate azimuth in initial alignment stage because sensor noise level is too large compare to Earth rotation rate, therefore the performance and stability of Kalman filter can not be guaranteed. In this paper, the extended Kalman filter and particle filter combined filter structure which can be overcome large initial azimuth error is proposed.
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A Dynamic Route Search Algorithm for Time-Sensitive Air Cargo in Air Traffic Management
조태환 Tae Hwan Cho , 김강희 Kang Hee Kim , 최상방 Sang Bang Choi
16(5) 744-751, 2012
조태환 Tae Hwan Cho , 김강희 Kang Hee Kim , 최상방 Sang Bang Choi
DOI: JANT Vol.16(No.5) 744-751, 2012
Air Traffic Management(ATM) is to control air traffic flow quickly and safely. For efficient ATM, the ability which calculate optimal route using filight plan and filght information is required. Especially for the time-sensitive air cargo, it is essential. In this paper, therefore, we present a dynamic route search algorithm which calculate optimal route dynamically. The conventional method using Dijkstra algorithm has a problem that recalculate the entire route when some airways are closed. However, the proposed algorithm recalculates only affected waypoints, so it finds optimal route quickly and accurately. Comparisons with the conventional method and the proposed algorithm show that the proposed algorithm provides better.
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Accuracy Analysis of Precise Point Positioning Using Predicted GPS Satellite Orbits
하지현 Ji Hyun Ha , 허문범 Moon Beom Heo , 남기욱 Gi Wook Nam
16(5) 752-759, 2012
하지현 Ji Hyun Ha , 허문범 Moon Beom Heo , 남기욱 Gi Wook Nam
DOI: JANT Vol.16(No.5) 752-759, 2012
In this paper, near-real-time positioning accuracies of precise point positioning technique were analyzed using IGS predicted orbits. As a result, we could get the mean errors of 1~1.6 cm, standard deviation of 1~1.3cm from one year of GPS data. This results were similar level to positioning accuracy using the IGS rapid orbits. Positioning errors of >10cm showed 44% of observed days of orbital anomalies. When the orbital anomalies of the predicted orbits were shown, maximum error was 1.7 km, and maximum of mean errors was 308 m. From this study, we conclude that check and consideration were necessary before using the IGS predicted orbits.
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Design of a Broadband Quasi-Yagi Antenna with a 2:1 Impedance Bandwidth Ratio
이종익 Jong Ig Lee , 여준호 Jun Ho Yeo , 박진택 Jin Taek Park
16(5) 760-765, 2012
이종익 Jong Ig Lee , 여준호 Jun Ho Yeo , 박진택 Jin Taek Park
DOI: JANT Vol.16(No.5) 760-765, 2012
In this paper, we studied a design method for a quasi-Yagi antenna (QYA) with broadband characteristics of an impedance bandwidth ratio greater than 2 : 1 and a gain > 4 dBi. The QYA is fed by a microstrip line fabricated on a coplanar strip line and it consists of 3 elements; a planar dipole, a nearby director close to the dipole, and a ground plane reflector. By placing a wide rectangular patch-type director near to the dipole driver, broadband characteristics are achieved. An optimized 3-element QYA for operation over 1.6-3.5 GHz bandwidth ratio 2.2 : 1) is fabricated on an FR4 substrate with a size of 90 mm by 90 mm and tested experimentally. The results show an impedance bandwidth of 1.56-3.74 GHz (bandwidth ratio 2.4 : 1) for VSWR < 2, a peak gain of 4.2-6.3 dBi, and a front-to-back ratio (FBR) > 13.6 dB within the bandwidth.
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Design of wideband microstrip monopole slot antenna
이영순 Young Soon Lee , 조윤기 Yun Ki Cho
16(5) 766-772, 2012
이영순 Young Soon Lee , 조윤기 Yun Ki Cho
DOI: JANT Vol.16(No.5) 766-772, 2012
In the present study, wideband microstrip monopole slot antennas which can be applied to the RF4CE Zigbee remote controller are designed. First I-shaped monopole slot antenna which has λg/4 length at 2.45GHz is designed. In particular, a conducting via is used to connect the microstrip feed line and the ground plane surrounded with the etched slot for the bandwidth improvement. In order to reduce the antenna size, it is changed into L-shaped and T-shaped monopole slot antennas for which improve results of antenna performance are observed. In case of T-shaped monopole slot antenna, impedance bandwidth(VSWR<2) is about 3.32GHz, and also its radiation efficiency and gain is more than 90% and 2.1dBi respectively at whole operating frequency range. In particular, all of proposed monopole slot antennas have the end-fire radiations which has a maximum radiation power toward direction of open ends of monopole slots.
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Design of ZOR antenna for 2.45GHz WLAN using CRLH-TL
김승환 Seung Hwan Kim , 유진하 Jin Ha Yu , 이영순 Young Soon Lee
16(5) 773-780, 2012
김승환 Seung Hwan Kim , 유진하 Jin Ha Yu , 이영순 Young Soon Lee
DOI: JANT Vol.16(No.5) 773-780, 2012
ZOR(zeroth order resonance) antenna for 2.45GHz WLAN(wireless local area network) is designed by use of CRLH-TL(composite right left handed transmission line) meta-material. The electrical length of conventional antennas is determined generally according to the resonant frequency, whereas that of ZOR antenna can be determined without reference to the resonant frequency. Therefore ZOR antenna has advantage in miniaturization of antenna in comparison with conventional antennas. In order to design such ZOR antenna, first unit cell with electrical length shorter than a quarter wavelength at 2.45GHz is designed to the some characteristics of homogeneous medium. In order to decrease resonant frequency and enhance frequency bandwidth, the proposed antenna is fed by CPW(co-planar waveguide) and short stub between radiation patch and ground plane is used for obtaining both higher inductance and smaller capacitance than previous mush-room type of CRLH-TL.
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An Unequal Divider based on Transmission Line with Periodic Capacitor Shunt Connection
김영 Young Kim , 윤영철 Young Chul Yoon
16(5) 781-786, 2012
김영 Young Kim , 윤영철 Young Chul Yoon
DOI: JANT Vol.16(No.5) 781-786, 2012
In this paper, we propose the design and performance of an unequal divider using transmission line with periodic capacitor shunt connection. To design divider with a high dividing ratio, we limit a high impedance line value to fabricate microstrip line and also, design a low impedance line of below 10 Ω using periodic capacitor shunt connection. As a design example, a 10:1 ratio divider was designed and measured at center frequency 1 GHz to show the validity of the unequal divider using periodic capacitor shunt connection. Its performance is in good agreements with the simulated results.
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Security Analysis of Block Cipher Piccolo-128 Applicable to Various Environments
정기태 Ki Tae Jeong
16(5) 787-793, 2012
정기태 Ki Tae Jeong
DOI: JANT Vol.16(No.5) 787-793, 2012
Piccolo-128 is a 64-bit ultra-light block cipher suitable for the constrained environments such as wireless sensor network environments. In this paper, we propose biclique cryptanalysis on the full Piccolo-128. To recover the secret key of Piccolo-128, the proposed attack requires 224chosen plaintexts and the computational complexity of about 2127.35. This result is the first known theoretical attack result on the full Piccolo-128.
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Performance Improvements in Guard Channel Scheme by Resource Prediction for Wireless Cognitive Radio-Based Cellular Networks
이진이 Jin Yi Lee
16(5) 794-800, 2012
이진이 Jin Yi Lee
DOI: JANT Vol.16(No.5) 794-800, 2012
In this paper, we propose a scheme for improving not only the utilization of frequency bands in the guard channel scheme but also the dropping rate of cognitive radio user in the wireless cognitive radio-based cellular network. The proposed scheme enables cognitive radio users to utilize the guard channel for servicing only handoff calls in normal times, but cognitive radio users must vacate the frequency channel when handoff call appearing. At this time our scheme ensures their seamless services for cognitive radio users, by predicting handoff call`s appearance by MMOSPRED (Multi-Media One Step Prediction) method and then reserving the demanded channels for spectrum handoff calls. Our simulations show that our scheme performs better than other schemes; GCS(Guard Channel Scheme) and a scheme without prediction in terms of cognitive users call`s dropping rate and resource utilization efficiency.
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Compensation for Distorted WDM Signals Through Dispersion Managed Optical Transmission Links with Ununiform Distribution of SMF Length and RDPS of Optical Fiber Spans
이성렬 Seong Real Lee
16(5) 801-809, 2012
이성렬 Seong Real Lee
DOI: JANT Vol.16(No.5) 801-809, 2012
Dispersion management (DM) is the typical technique compensating for the distorted signals due to interaction of group velocity dispersion (GVD) and optical nonlinear effects for transmitting wavelength division multiplexed (WDM) channel with the excellent performance. Optimal net residual dispersion (NRD) and effective launching power range of optical transmission links with random distribution and artificial distribution of single mode fiber (SMF) length and residual dispersion per span (RDPS) required to flexibly design of optical links in DM. It is confirmed that optimal net residual dispersion (NRD) are +10 ps/nm and -10 ps/nm controlled by precompensation and postcompensation, respectively, in both of the considered distribution patterns of SMF length and RDPS. And, in optimal NRD, system performance in optical links with the descending distribution of SMF length and the ascending distribution of RDPS among the artificial distribution patterns are more improved, consequently, effective launching power range is expanded by almost 2 dB than those in optical links with the uniform distribution.
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Performance Analysis of a TransferJet System
박경원 Kyung Won Park , 위정욱 Jeong Wook Wee , 서정욱 Jeong Wook Seo , 전원기 Won Gi Jeon
16(5) 810-816, 2012
박경원 Kyung Won Park , 위정욱 Jeong Wook Wee , 서정욱 Jeong Wook Seo , 전원기 Won Gi Jeon
DOI: JANT Vol.16(No.5) 810-816, 2012
In this paper, BER(Bit Error Ratio) performances of the TransferJet system, which is the standard of a close proximity inductive wireless communication system, are presented and analyzed. Comparing to other wireless communication systems, the TransferJet system has some advantages such as short communication range(i.e., high security in the wireless communication environments), fewer effects of multipath distortion, and higher transmission rate. In order to demodulate the received signal, either SC(Soft-decision Combining) or HC(Hard-decision Combining) can apply to the despreader and demodulator of the receiver. When the spreading factor is more than 4, the SC scheme approximately has a minimum signal-to-noise ratio gain of 2 dB over the HC scheme. Moreover, from simulation results, we can conclude that the quantization bits of 3 bits are an optimum value for the SC scheme in the TransferJet system since the 3-bit quantization achieves nearly the performance as that attained by double-precision floating-point.
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S/W model of Plastic Slice for Semi-federated Slice Control of Future Internet Testbed
차병래 Byung Rae Cha , 김종원 Jong Won Kim
16(5) 817-830, 2012
차병래 Byung Rae Cha , 김종원 Jong Won Kim
DOI: JANT Vol.16(No.5) 817-830, 2012
In rapid changes in communications and computing environment, due to the increasing variety of user requirements, and an effort to solve the fundamental problems with the current Internet, Future Internet researches actively have been performed at domestic and abroad. In this paper, we proposed the idea and basic concept of Plastic slice software mode about federation job control in study topic of future internet.
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Composition Rule of Character Codes to efficiently transmit in HDLC Protocol with HDB-3 Scrambling
홍완표 Wan Pyo Hong
16(5) 831-838, 2012
홍완표 Wan Pyo Hong
DOI: JANT Vol.16(No.5) 831-838, 2012
In the transmission system, the transmission efficiency can be increased by applying the proper character coding method. This paper is to show the character coding rule in computer and information equipment etc to improve the transmission efficiency in datacommunications. The character coding rule showing in this paper was suggested by considering the two view points. First one is FLAG bits in HDLC and PPP protocol on datalink layer in OSI 7 layer. Second one is one of the scrambling method, HDB-3, on physical layer in OSI 7 layer. The former is to prevent the sequence of over 5bits of "1" in the character codes. The latter is to prevent the sequence of over 4bits of "0" in the character codes.
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The Implementation of Embedded Web Server System for a Remote Control and Measurement
이명의 Myung Eui Lee
16(5) 839-845, 2012
이명의 Myung Eui Lee
DOI: JANT Vol.16(No.5) 839-845, 2012
This paper deals with the design and development of the remote control and measurement systems by Embedded Web Server. The remote control and measurement systems are implemented by Cortex M-3 ARM micro-controller. The user application software for the control and measurement system user, and the firmware software of device drivers for peripherals such as a digital input/output device, AD/DAC(Analog to Digital/Digital to Analog Converter), LCD, and temperature/humidity sensor are developed in Eclipse environment using Codesourcery C, Java script, and HTML. The experimental result of the proposed control and measurement systems implemented in this paper is evaluated via real-time experiments, which works well as designed.
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The Estimation of Parameters to minimize the Energy Function of the Piecewise Constant Model Using Three-way Analysis of Variance
주기세 Ki See Joo , 조덕상 Deog Sang Cho , 서재형 Jae Hyung Seo
16(5) 846-852, 2012
주기세 Ki See Joo , 조덕상 Deog Sang Cho , 서재형 Jae Hyung Seo
DOI: JANT Vol.16(No.5) 846-852, 2012
The result of imaging segmentation becomes different with the parameters involved in the segmentation algorithms; therefore, the parameters for the optimal segmentation have been found through a try and error. In this paper, we propose the method to find the best values of parameters involved in the area-based active contour method using three-way ANOVA. The segmentation result applied by three-way ANOVA is compared with the optimal segmentation which is drawn by user. We use the global consistency rate for comparing two segmentations. Finally, we estimate the main effects and interactions between each parameter using three-way ANOVA, and then calculate the point and interval estimate to find the best values of three parameters. The proposed method will be a great help to find the optimal parameters before working the motion segmentation using piecewise constant model.
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Mediation Effect of Organizational Identification of Perceived Organization Support and Supervisor Support that Impact on Dual Commitment -focus on Airline Employees-
윤선영 Sun Young Yoon
16(5) 853-863, 2012
윤선영 Sun Young Yoon
DOI: JANT Vol.16(No.5) 853-863, 2012
The purpose of this study is to investigate mediatiing effects of perceived organization support and supervisor support that impact on dual commitment. Data were gathered from 188 employees who were working in Airlines. In the result of the hypothesis verification, First, perceived organization support and supervisor support have positive effects on dual commitment. Second, organiational identification turns out to have the mediating role in the relationship between perceived organization support and supervisor support and dual commitment. Finally, implication of results and future tasks were discussed with limitations.
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Interactive content development of voice pattern recognition
나종원 Jong Won Na
16(5) 864-870, 2012
나종원 Jong Won Na
DOI: JANT Vol.16(No.5) 864-870, 2012
Voice pattern recognition technology to solve the problems of the existing problems and common issues that you may have in language learning content analysis. This is the first problem of language-learning content, online learning posture. Game open another web page through the lesson, but the concentration of the students fell. Have not been able to determine the second issue according Speaking has made the learning process actually reads. Third got a problem with the mechanical process by a learning management system, as well by the teacher in the evaluation of students and students who are learning progress between the difference in the two. Finally, the biggest problem, while maintaining their existing content made to be able to solve the above problem. Speaking learning dedicated learning programs under this background, voice pattern recognition technology learning process for speech recognition and voice recognition capabilities for learning itself has been used in the recognition process the data of the learner`s utterance as an audio file of the desired change to a transfer to a specific location of the server or SQL server may be easily inserted into any system or program, any and all applicable content that has already been created without damaging the entire component because the new features were available. Contributed to this paper, active participation in class more interactive teaching methods to change.
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Differential Fault Analysis on Lightweight Block Cipher LBlock
정기태 Ki Tae Jeong , 이창훈 Chang Hoon Lee
16(5) 871-878, 2012
정기태 Ki Tae Jeong , 이창훈 Chang Hoon Lee
DOI: JANT Vol.16(No.5) 871-878, 2012
LBlock is a 64-bit ultra-light block cipher suitable for the constrained environments such as wireless sensor network environments. In this paper, we propose a differential fault analysis on LBlock. Based on a random nibble fault model, our attack can recover the secret key of LBlock by using the exhaustive search of 225 and five random nibble fault injection on average. It can be simulated on a general PC within a few seconds. This result is superior to known differential fault analytic result on LBlock.
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Design of Emergency Management System for Societal Security Network
김윤호 Yoon Ho Kim , 강희조 Hee Jo Kang
16(5) 879-884, 2012
김윤호 Yoon Ho Kim , 강희조 Hee Jo Kang
DOI: JANT Vol.16(No.5) 879-884, 2012
In accelerating the industrialization, human being have been frequently experiencing man-made crisis such as technology failures, financial problem as well as natural disaster. Emergency management system based on international standard can provide an organization with a framework for continual improvement to increase the possibility of enhancing anticipation, prevention and response as well. In this paper, we introduced the emergency management system design of various organizations for societal security network. In the first, the main role of ISO/TC223 is reviewed and then, current issues of under going standardization in ISO are also addressed. Finally, we have designed a efficient disaster prevention system to minimize the potential risk as well as to improve the organizational resilience.
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