The Operation Characteristic of the LED Taxi Light for Wavelength According to Meteorological Changes for Hybrid System Using a ESS
황락훈 Lark-hoon Hwang , 김진선 Jin-sun Kim , 나용주 Yong-ju Na
20(4) 265-274, 2016
황락훈 Lark-hoon Hwang , 김진선 Jin-sun Kim , 나용주 Yong-ju Na
DOI: JANT Vol.20(No.4) 265-274, 2016
In this study, the system was composed of the booster chopper and the power converter, which is a pulse width modulation (PWM) voltage inverter using a hybrid power generation system solar cell energy and wind force, Furthermore, in order to compensate the PWM voltage type inverter was linked with the general commercial power source, and through a normal operation of energy storage system (ESS), the system operated the LED Taxi Light by Wavelength according to Meteorological Changes at the airport in an efficient manner. The performance of the system was compared with the solar cell characteristics specification. In addition, for phase synchronization with the PWM voltage type inverter, the grid voltage was detected so as to operate the grid voltage and inverter output in the same phase and to connect the surplus electric power with the system. Finally, by developing a control circuit at the same time from which an excellent dynamic characteristics can be obtained through applying to the airport runway taxi light, it was concluded that a variety of taxi light can be pursued.
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Emission Estimation for Airports in Korea Using AEIC Program
주희진 Hee-jin Joo , 황호연 Ho-yon Hwang , 임동욱 Dongwook Lim
20(4) 275-284, 2016
주희진 Hee-jin Joo , 황호연 Ho-yon Hwang , 임동욱 Dongwook Lim
DOI: JANT Vol.20(No.4) 275-284, 2016
The potential impact of aircraft emissions on the current and projected climate of our planet is one of the more important environmental issues facing the aviation industry. Increasing concern over the potential negative effects of greenhouse gas emissions has motivated aircraft emission estimation and prediction as one of the ways to reduce aircraft emissions and mitigate the impact of aviation on climate. We obtained airline flight schedules for all the airports in Korea that are included in OAG data. Fuel burn and emission index of LTO flight which contains take off, climb and approach under 3000ft and Non LTO flight which contains climb, cruise and descent over 3000ft for all the airports in Korea in 2005 were estimated and analysed for each condition using AEIC software which has been developed by MIT Lab for Aviation and Environment.
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Hazard Assessment Methodology Based on Target Level of Safety for CNS/ATM System
이홍석 Hongseok Lee , 조상훈 Sanghoon Jo
20(4) 285-291, 2016
이홍석 Hongseok Lee , 조상훈 Sanghoon Jo
DOI: JANT Vol.20(No.4) 285-291, 2016
Safety assessment is an essential activity for developing a system in the CNS/ATM domain. Up to now, there are many reference materials, but there is nothing that definitely specifies what to do and how to apply in the CNS/ATM. Another problem is that software assurance level has to be determined for a software under development. But there is nothing that defines a determination scheme of software assurance level. To solve these problems, this paper proposes a method to conduct a hazard assessment based on target level of safety defined in ICAO Doc 9689. To be applied generally in CNS/ATM domain, it mathematically defines procedures of hazard assessment. And it defines severity classification, probability, and safety objective of a system, which are necessary for hazard assessment, and it describes a method to apply event tree analysis process in order to conduct a hazard assessment.
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Proposed STAR Procedure of Incheon International Airport Considering Safety and Efficiency
장재호 Jaeho Chang
20(4) 292-297, 2016
장재호 Jaeho Chang
DOI: JANT Vol.20(No.4) 292-297, 2016
Since continuous descent operations (CDO) is one of several tools available to aircraft operators and air navigation service providers (ANSPs) to increase safety, flight predictability, and airspace capacity while reducing noise, controller-pilot communications, fuel burn and emissions, widespread implementation of CDO would result in significant reductions in the environmental impact and aircraft operation costs in south korea as well. After analyzing each procedure from standard terminal arrival routes used for the Incheon international airport, it can be noticed that one of the procedures has a relatively high altitude constraint at initial approach fix than others, which lead the pilots to use unnecessary drag device in certain situations. Therefore we came to a conclusion that some arrival procedures need to be revised, so unnecessary procedure required during approach can be minimized, thereby reducing fuel consumption, noise and emissions compared to current approach procedures. And it is going to increase the safety margin significantly during approach phase due to reduced workload.
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Ultrasonic Rangefinder Spike Rejection Method Using Wavelet Packet Transform
김성훈 Sung-hoon Kim , Kyeung-sik Choi , 홍교영 Gyo-young Hong
20(4) 298-304, 2016
김성훈 Sung-hoon Kim , Kyeung-sik Choi , 홍교영 Gyo-young Hong
DOI: JANT Vol.20(No.4) 298-304, 2016
In this paper, a wavelet packet transform method is proposed for improving the altitude control performance of quadrotor UAV using an ultrasonic rangefinder. A ground tests are conducted using an ultrasonic rangefinder that is much used for vertical takeoff and landing. An ultrasonic rangefinder suffers from signal’s spike due to specular reflectance and acoustic noise. The occurred spikes in short time span need to be analyzed at both sides time and frequency domain. The analyzed spikes of the ultrasonic rangefinder using a wavelet packet transform. Compared with the discrete wavelet transform, the wavelet packet decomposition can obtain more abundant time-frequency localization information, so it is more suitable for analyzing and processing ultrasonic signals spike. Experimental results show that it can effectively remove the spikes of the ultrasonic rangefinder.
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Study on Technical Standard of Aviation GNSS for SBAS Performance Based Navigation
박재익 Jae-ik Park , 이은성 Eunsung Lee , 허문범 Moon-beom Heo , 남기욱 Gi-wook Nam
20(4) 305-313, 2016
박재익 Jae-ik Park , 이은성 Eunsung Lee , 허문범 Moon-beom Heo , 남기욱 Gi-wook Nam
DOI: JANT Vol.20(No.4) 305-313, 2016
International Civil Aviation Organization (ICAO) has recommended the adoption of performance-based navigation (PBN), which utilizes global navigation satellite system (GNSS). As a part of efforts to adopt PBN in South Korea, preparations have been made to implement GNSS. In Oct. 2014, Korea augmentation satellite system (KASS) was officially launched for development. A set of navigation devices need to be on-board for an airplane to utilize GNSS. GNSS navigation devices are used for different phases of flights through en-route, terminal, departure, approach and a wide variety of specification standards have been proposed for GNSS navigation. In this paper, we investigate the many proposed standards for GNSS navigation devices and their interfaces. This paper can be useful for designing procedures and flight test used in KASS implementation.
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Aided Navigation Algorithm for Land Navigation System Using VMS with Indirect Drive Condition
김형수 Hyungsoo Kim
20(4) 314-320, 2016
김형수 Hyungsoo Kim
DOI: JANT Vol.20(No.4) 314-320, 2016
Inertial navigation system (INS) has used aided systems and sensors to compensate navigation error. Global navigation satellite system (GNSS), velocity measurement sensor (VMS), and radar are commonly used to aid INS. Land navigation system (LNS) also mainly uses VMS when GNSS cannot be used such as at tunnel or on jammed scenario. A straight drive is required when VMS-aided navigation is used, because there is only speed of straight direction whereas no crossways and vertical directions. In local environment, even an expressway has lack of straight drive which is constraint of VMS-aided navigation algorithm. This paper proposes an enhanced VMS-aided navigation algorithm for LNS with indirect drive by restricting filter update condition. Also, there is a result of vehicle test to prove performance of the proposed algorithm.
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Research on Fault Tolerant Avionics Memory Design through Multi Level Cell Flash Memory Reliability Analysis
정상규 Sang-gyu Jeong , 전병규 Byung-kyu Jun , 김영목 Young-mok Kim , 장인기 In-ki Chang
20(4) 321-328, 2016
정상규 Sang-gyu Jeong , 전병규 Byung-kyu Jun , 김영목 Young-mok Kim , 장인기 In-ki Chang
DOI: JANT Vol.20(No.4) 321-328, 2016
Typical MLC NAND flash devices are considered less reliable than SLC NAND flash devices. Although raw bit error rate (RBER) of MLC flash had been considered approximately 1000times or more higher than that of SLC flash, recent research conducted on Google’s data center shows that it is much lower than such expectation. Based on the research, we devised In Drive Data Duplication (IDDD) scheme that efficiently exploit MLC flash’s sufficient capacity to improve its data reliability without structural complexity increment using SSD intrinsic firmware layer, and showed the data reliability expectation of MLC flash could be significantly higher than that of SLC flash from measured and calculated error rates. Even though RBER of SLC flash was lower than that of MLC flash in 44 out of 48 cases we studied, applying IDDD scheme, RBER of MLC flash was became lower than that of SLC in all 48 cases and uncorrectable bit error rate (UBER) of MLC flash was became lower than that of SLC flash in 45 out of 48 cases.
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Technology Trends and Performance Evaluation for Unmanned Aircraft System Datalink
황현수 Hyunsu Hwang , 정용철 Yongcheol Jung , 정윤호 Yunho Jung
20(4) 329-335, 2016
황현수 Hyunsu Hwang , 정용철 Yongcheol Jung , 정윤호 Yunho Jung
DOI: JANT Vol.20(No.4) 329-335, 2016
Unmanned aircraft systems (UAS) are defined as the system whose components include the necessary equipment, network, and personnel to control an unmanned aircraft. In the past, UAS were predominately operated for military operations. However, nowadays, the applications of UAS to commercial area are explosively augmented and UAS are being expected to be integrated in national airspace. Therefore, the need for the standardized datalink systems rapidly and the development of control and non-payload communication (CNPC) system are being processed for integration in national airspace in United States and Europe. In this paper, the technology trends for UAS CNPC datalink are explained and presented the performance evaluation results for CNPC system, which is the modified version of IEEE 802.15.4 ZigBee system.
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Measure to Introduction of Performance-Based Communication and Surveillance (PBCS) in Korea
홍승범 Seung-boem Hong , 최원혁 Won-hyuck Choi
20(4) 336-343, 2016
홍승범 Seung-boem Hong , 최원혁 Won-hyuck Choi
DOI: JANT Vol.20(No.4) 336-343, 2016
Future air navigation system (FANS) Committee overcomes the limitations of traditional systems, the development of worldwide new system that allows the development of air traffic management have been determined to be necessary. In order to accommodate the rapid increase in aircraft traffic and maximize the safe air navigation efficiency, ICAO is recommending a new performance-based communications and surveillance (PBCS) system . However, although utilizing wireless data link in the case of korea currently, the introduction of the PBCS is not performed normally. In this paper, we review the concept of PBCS, and aviation developed countries look to the applied case of PBCS. It also analyzes trends and status and problems of Korea and introduce future policy directions for CNS/ATM system improvement.
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L-shaped Slot Antenna for WLAN MIMO Application
송원호 Won-ho Song , 남주열 Ju-yeol Nam , 이기용 Ki-yong Lee , 이영순 Young-soon Lee
20(4) 344-351, 2016
송원호 Won-ho Song , 남주열 Ju-yeol Nam , 이기용 Ki-yong Lee , 이영순 Young-soon Lee
DOI: JANT Vol.20(No.4) 344-351, 2016
In the present study, a dual-band multiple-input-multiple-output (MIMO) antenna covering WLAN frequency bands of 2.4 GHz (2.4 ~ 2.484 GHz) and 5 GHz (5.15 ~ 5.825 GHz) is newly presented to avoid use of decoupling structure for increasing isolation. The antenna consists of two L-shaped slots with n-shaped slots etched on the floating ground plane surrounded by open ended L-shaped slots which are placed in the left and right corner of PCB respectively. The proposed antenna is designed and fabricated on one side of FR4 substrate with dielectric constant of 4.3, thickness of 1.6 mm, and size of 50 × 50 ㎟. It has been observed that the measured impedance bandwidths (S11 ≤-10 dB) are 0.3 GHz (2.28 ~ 2.58 GHz) in 2.4 GHz frequency band and 0.89 GHz (5.11 ~ 6 GHz) in 5 GHz frequency band respectively. In addition, It has been observed that the whole efficiency are more than 80 % in the whole operating frequency band and envelope correlation coefficient of the antenna is less than 0.05 as a very small value in spite of nothing of the decoupling structure.
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An Efficient WLAN Multicasting Scheme
안진수 Jinsoo Ahn , 조봉관 Bong-kwan Cho , 김용호 Ronny Yongho Kim
20(4) 352-360, 2016
안진수 Jinsoo Ahn , 조봉관 Bong-kwan Cho , 김용호 Ronny Yongho Kim
DOI: JANT Vol.20(No.4) 352-360, 2016
In this paper, a novel multiple multicast feed-back scheme for improving multimedia multicast and broadcast system based on IEEE 802.11. The proposed scheme improves multicast PPDU delivery ratio of next generation wireless LAN by utilizing multicast feed-back information. By using the proposed scheme, regardless of its size of multicast group, an AP STA could collect transmission failure information by receiving simultaneous NAK frame. The proposed scheme shows large performance enhancement in broadcast or multicast system of Intelligent Transport System and Passenger Entertainment Service. According to the analysis results, the proposed scheme could enhance wireless LAN multicast and broadcast performance significantly.
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An Impedance Transformer with Unequal Split Based on S-Parameter Conversion
김영 Young Kim
20(4) 361-366, 2016
김영 Young Kim
DOI: JANT Vol.20(No.4) 361-366, 2016
This paper presents an arbitrary impedance transformer with unequal split, based on S- to admittance parameter conversion. When compared even/ odd- mode analysis, the parameter conversion design method constitutes a simple design method to include phase delay information and arbitrary port impedances and asymmetrical configurations. To validate this design method, we designed a 50 to 12.5 Ω impedance transformer with a 3:1 unequal power split, at an operating frequency of 1 GHz. To implement the proposed impedance transformer, the low impedance transmission lines of calculated result are fabricated by the transmission line connected shunt open stub. Good experimental performances were obtained, in full agreement with simulated results.
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Improved Direction of Arrival Estimation Based on Coprime Array and Propagator Method by Noise Power Spectral Density Estimation
변부근 Bu-guen Byun , 유도식 Do-sik Yoo
20(4) 367-373, 2016
변부근 Bu-guen Byun , 유도식 Do-sik Yoo
DOI: JANT Vol.20(No.4) 367-373, 2016
We propose an improved direction of arrival (DoA) estimation algorithm based on co-prime array and propagator method. The propagator method with co-prime array does not require singular value decomposition (SVD) requiring much less computational complexity but exhibiting somewhat worse performance in comparison with MUSIC based on co-prime array. We notice that one cause of the performance degradation was in the avoidance of the usage of the diagonal elements of the signal autocorrelation matrix that contains the noise power spectral density. So we propose an algorithm with the diagonal elements of the signal autocorrelation matrix based on the fact that the noise power spectral density can be estimated using noise observation over a long period of time. We observe, through simulations, that the proposed scheme in this paper improves the performance, with 4 times more computational requirement, by signal-to-noise ratio of 1.5dB and by DoA resolution of 0.7° at the detection probability of 95% compared with the previously introduced co-prime array propagator scheme, resulting in performance much closer to that of co-prime array-based MUSIC scheme.
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A Study of Data Communication Between the Web and the IoT Platform in WoT
표경수 Gyung-soo Phyo , 박진태 Jin-tae Park , 문일영 Il-young Moon
20(4) 374-379, 2016
표경수 Gyung-soo Phyo , 박진태 Jin-tae Park , 문일영 Il-young Moon
DOI: JANT Vol.20(No.4) 374-379, 2016
Recently, IoT(Internet of Things) to connect the objects and people has attracted attention. And it is rapidly developing. IoT is to develop, experts are predicting that the device is connected to the Internet to break through around 100 billion within 10 years. However, the current IoT companies are having a difficult state to the other each other IoT platform for interaction between data silos effects. These silos effects will limit the IoT grow to a larger market. Thus, the IoT service supplier shall develop an open platform for interaction IoT data between each IoT platform. These web technologies for current open IoT platform has emerged. If developers are using familiar, easy-to-learn Web technologies, developers can take advantage of a variety of services for the collected data, and found the IoT devices can be bypassed if there is a problem on the network. In this paper, we investigate the data communications technology that can be used in WoT environment to overcome these silos effects. As a result, the polling method that can simply send the IoT information the fastest.
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Shadow Detection Based Intensity and Cross Entropy for Effective Analysis of Satellite Image
박기홍 Ki-hong Park
20(4) 380-385, 2016
박기홍 Ki-hong Park
DOI: JANT Vol.20(No.4) 380-385, 2016
Shadows are common phenomena observed in natural scenes and often bring a major problem that is affected negatively in colour image analysis. It is important to detect the shadow areas and should be considered in the pre-processing of computer vision. In this paper, the method of shadow detection is proposed using cross entropy and intensity image, and is performed in single image based on the satellite images. After converting the color image to a gray level image, the shadow candidate region has been estimated the optimal threshold value by cross entropy, and then the final shadow region has been detected using intensity image. For the validity of the proposed method, the satellite images is used to experiment. Some experiments are conducted so as to verify the proposed method, and as a result, shadow detection is well performed.
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