강영흥 Young-houng Kang , 오대섭 Dae-sub Oh

DOI: JANT Vol.20(No.6) 503-510, 2016

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In recent years, owing to the growing user demand for the two-way internet service based on the move global broadband communications, a new type of satellite terminal has developed, known as earth station in motion (ESIM). This service was required by Resolution 158 (WRC-15) to study on the coexistence with the co-primary fixed service (FS) in 27.5-29.5 GHz as a FSS uplink. In this paper, four scenarios was introduced to account for the antenna pointing error and the azimuth for an analysis on the sharing between ESIM and FS. From analysis results, the required separation distance between two systems should be about 32~52 km according to the elevation angles of 20°~40° using thresholds of 5% and 10% outage probability. Therefore, it is necessary to control the azimuth angle due to a moving terminal as well as the pointing error of ESIM to minimize the required separation distance and to protect the co-primary FS.

방장규 Jang-kyu Bang , 이근영 Gun-young Lee

DOI: JANT Vol.20(No.6) 511-518, 2016

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RAPCON non only controls landing/take-off procedures but also approaching air traffics within 60-70 NM range of air force base. This paper, first of all, tries to research the failure rate per operation hours, mean time between failure (MTBF) of RAPCON according to six blocks such as interrogator, receiver, power unit, display unit, data process unit and antenna. In addition, this paper estimates the maintenance cost over next 10 months based on 50 monthly maintenance cost data. Considering the maintenance cost data from RAPCON which has been used over designed service life span, it is no doubt the forecasted data proved the monthly cost would go up incrementally during the rest of economic life of the facility. Such research result is also proven to be the same with the result of bathtub curve data during operating life.

강남선 Nam-seon Kang , 김용대 Yong-dae Kim , 윤현규 Hyeon-kyu Yoon , 변상수 Sang-su Byeon

DOI: JANT Vol.20(No.6) 519-527, 2016

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The present study is concept research on the operation cost management of shipping firms, especially considering technology for economical ship operation of existing ships in units of voyage. The factors that influence economical ship operation management were identified by analyzing the current status of the shipping industry, the development of economical ship operation technologies, technological requirements, and the cost factors of ship operation. Economical operation of existing ships, especially, the economical operation of the units of each voyage, may minimize fuel cost and port charges. This requires low-load streaming cruise control, ballast control, optimal trim, optimal routing, terminal work efficiency improvement, and ship energy management. Optimal routing and terminal work efficiency improvement manage the time saved. To determine the low-load streaming, cruise control, ballast control, optimal trim and ship energy management are meeting the recommendations.

이주현 Ju Hyun Lee , 이진혁 Jin Hyuk Lee , 최헌호 Heon Ho Choi , 최효기 Hyogi Choi , 박찬식 Chansik Park , 이상정 Sang Jeong Lee , 이승찬 Seung Chan Lee

DOI: JANT Vol.20(No.6) 528-538, 2016

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In this paper, an extend kalman filter based relative navigation algorithm is proposed for Link-K based relative navigation. Link-K is a tactical data link system for joint operation capability upgrade of ROK forces. Link-K is inter-operable with Link-16 and transmit and received information of operations and target. In Link-K communication channel, PPLI message including transmitter position and TOA measurement can be used for relative navigation. Therefore Link-K based relative navigation system can be operated. In this paper, software based simulations were carried out for operational feasibility test and performance verification as error factors of proposed Link-K based relative navigation system.

김성훈 Sung-hoon Kim , 홍교영 Gyo-young Hong

DOI: JANT Vol.20(No.6) 539-543, 2016

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In this paper, we study the technique to improve the performance of the aerial images taken by UAV using daubechies stationary wavelet transform. When aerial images taken by UAV were damaged by gaussian noise very commonly applied, the experiment for image performance improvement was performed. It was known that stationary wavelet transform is the transferring solution to the problem occurred by down sampling from DWT also more efficient to remove noise than DWT. Also haar wavelet is discontinuous function so not efficient for smooth signal and image processing. Therefore, this study is confirmed that the noise can be removed by daubechies stationary wavelet and the performance is improved by haar stationary wavelet.

송종선 Jong-sun Song , 이영길 Yung-kil Lee

DOI: JANT Vol.20(No.6) 544-555, 2016

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Organizations of airport continue to invest heavily in the acquisition of self-esteem. Because, it is that self-esteem will become more productive. In this article, We verify to influence in the operation performance by the air navigation system and moderated effect of self-esteem. A survey of Incheon International Airport and Gimpo International Airport was conducted to better understand the factors that affect air navigation system to explain operation performance of airport perspective on air navigation system operator. The findings indicate that the positively moderated self-esteem affects operation performance of airports. We also confirmed that air navigation policy, maintenance, and promotion activities of air navigation system factors are affecting the operation performance of airports. The results of this study suggest that self-esteem could be the basis for a strong measurement tool to evaluate whether self-esteem in a given organization of airport are meeting enhancement of operation performance.

윤영철 Young-chul Yoon , 김영 Young Kim

DOI: JANT Vol.20(No.6) 556-561, 2016

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This paper describes implementation of a 13.56 MHz, 5 kW RF high power generator for ISM band applications. This RF generator consists of four LDMOS modules of 1.25kW class-AB push-pull power amplifier with drive amplifier and its outputs are combined by using Wilkinson type transmission-line transformers. Its generator has a high efficiency and output power better than linearity. In order to discharge power transistor heats, we used on water cooled copper plate. Also, these have a composite circuit of combiner and low-pass filter and safety circuit to detector over and reflected power. The RF generator has achieved a efficiency of 79 % at 5.33 kW of saturated power level experimentally.

표경수 Gyung-soo Phyo , 박진태 Jin-tae Park , 문일영 Il-young Moon

DOI: JANT Vol.20(No.6) 562-567, 2016

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IoT is attracting attention as the development of the Internet and the spread of smart devices are rapidly increasing worldwide. As IoT is integrated into everyday life, the market is getting bigger. So, experts predict that IoT devices will grow to more than one trillion in a decade. Techniques related to IoT are also being developed steadily, and studies are underway to develop IoT in various fields. However, vendors launching IoT services do not interact with data from other platforms. Therefore, it is limited to growing into a big market by facing the obstacle called the silo phenomenon. To solve this problem, web technology attracts attention. Web technology can interact with data regardless of platform, and it can not only develop various services using the data, but also reduce unnecessary costs for developers. In this paper, we have studied a web - based open IoT system that can transmit data independently in real time to the IoT platform.

최다솜 Da-som Choi , 강영흥 Young-heung Kang

DOI: JANT Vol.20(No.6) 568-573, 2016

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Since the existing analog village broadcasting system has some technical problems in applying and degradations in performance due to its old equipments, it had been required to be changed to a digital system and to develop the standardization from now. Therefore, we have analyzed the service coverage in various environments in order to construct an effective digital wireless village broadcasting system. Also, a precise prediction of field strength should be set up in various propagation environments to design a digital radio stations with reliable transmit power. Using these results the received power and the propagation characteristics in various environments can be predicted to establish a standard and the testing service will be deployed in the near future.

정원호 Won-ho Jung , 정재필 Jae-pil Chung

DOI: JANT Vol.20(No.6) 574-579, 2016

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Unlike general unmanned aerial vehicles, the quad-rotor is attracting the attention of many people because of simple structure and very useful value. However, as the interest in drones increases, the safety and location of vehicles are becoming more important provide against aviation safety accidents or lost accidents. Therefore, in this paper, we propose a tracking system that stabilizes the model with a simple controller by linearized modeling and grasp tilt angle data from various sensor through the filter. The developed tracking system transmits the position of the quad-rotor in flight to the computer and shows it through the route, so it can check the flight path and various information such as flight speed and altitude at the same time. Then the sensor used in the actual quad-rotor can not measure exact sensor data for disturbance and vibration. So we use sensor fusion of Kalman filter and Complementary filter to overcome this problem and the stability of the quad-rotor hovering is realized by PID control. Through simulation, various information such as the speed, position, and altitude of the quad-rotor were confirmed in real time.

박원태 Wontae Park

DOI: JANT Vol.20(No.6) 580-587, 2016

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In the purpose of suggesting the necessity and proper method of providing the standard reference material for acquiring the aircraft pilot license, this study provides the FAA and ROKAF case study, and positively analyzes the materials of 178 pilots and student pilots who acquired the aircraft pilot license. The result of case study shows that compared to the case of Korea which the restriction on the standard reference material providing exists, the FAA(Federal Aviation Administration) and ROKAF are currently providing the standard reference material. Additionally, the result of positive analysis indicates the fact that the necessity of standard reference material providing is well recognized and its importance also found to be remarkably high. These results represent that the standard reference material providing is necessary for training competent aircraft pilots. Also, this will mitigate the current shortage of aircraft pilots due to the rapid growth of air transportation industry, and this will play an important role in preventing diverse aircraft-related accidents.

장원창 Chang-one Jang , 박지상 Ji-sang Park , 이명의 Myung-eui Lee

DOI: JANT Vol.20(No.6) 588-594, 2016

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As more populations are getting older, the number of vulnerable pedestrians is increasing, thereby social problems related to transportations also frequently occur in different areas and situations. Many of such problems come from bus drivers who may pass bus stops not recognizing passengers about to board. In this paper, we propose a new IoT bus notification system developed to avoid these situations. Our implementation aims to gain bus service routes using publicly opened data, notify passengers about bus stop locations using GPS information and finally deliver the positions of those passengers to the bus drivers so that they can hardly miss passengers who are willing to board on the right stop. By creating an application, it was conducted by means of a GPS to communicate the location of the vehicle by means of GPS and transfer data to the location of the vehicle. Experimental results show that it is possible to accurately determine the position of passengers even in a crowded race area. The average error distance is 31m, and if the data to be processed as error is excluded, it provides a high reliability as 19m.

임원호 Wonho Lim , 정형찬 Hyoungchan Jeong , 아마드이쉬티아크 Ishtiaq Ahmad , 장경희 Kyunghi Chang

DOI: JANT Vol.20(No.6) 595-603, 2016

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In the Republic of Korea, the LTE-based public safety (PS-LTE) network is being built for the 700 MHz frequency band. However, the same bands are also assigned to the LTE-based high-speed railway (LTE-R) network. Therefore, it is essential to utilize the co-channel interference management schemes for the coexistence of two LTE networks in order to increase the system throughput and to reduce the user outage probability. In this paper, we focus on the downlink (DL) system for the coexistence of PS-LTE and LTE-R networks by considering non radio access network (RAN) sharing and LTE-R RAN sharing by PS-LTE users (UEs) to analyze the UE throughput. Moreover, we also utilize the cooperative communications schemes, such as coordinated multipoint (CoMP) for the coexistence of PS-LTE and LTE-R networks in order to reduce the UE outage probability. We categorize the coexistence of PS-LTE and LTE-R networks into four different scenarios, and evaluate the performance of each scenario by the important performance indexes, such as UE average throughput and UE outage probability.

정형찬 Hyoungchan Jeong , 임원호 Wonho Lim , 하유경 Yujing He , 장경희 Kyunghi Chang

DOI: JANT Vol.20(No.6) 604-611, 2016

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Drone, which refers to unmanned aerial vehicles (UAV), industries are improving rapidly and exceeding existing level of remote controlled aircraft models. Also, they are applying automation and cloud network technology. Recently, the ability of drones can bring serious threats to public safety such as explosives and unmanned aircraft carrying hazardous materials. On the purpose of reducing these kinds of threats, it is necessary to detect these illegal drones, using acoustic feature extraction and classifying technology. In this paper, we introduce sound feature vector extraction method by harmonic feature extraction method (HLA). Feature vector extraction method based on HLA make it possible to distinguish drone sound, extracting features of sound data. In order to assess the performance of distinguishing sounds which exists in outdoor environment, we analyzed various sounds of things and real drones, and classified sounds of drone and others as simulation of each sound source.

최기성 Ki-seong Choi , 최규식 Gyu-shik Che

DOI: JANT Vol.20(No.6) 612-616, 2016

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Gamma-ray must be detected and processed immedietely after generation of it in the circumstances where it exists. Software methology may be used to process randomly generated signals, but its memory size and processing time become large. By the way, the hardware circuit to detect randomly generated signals is generalized in industrial site, while those circuits are not able to answer to the cases whose amplitude are very small and also speed high. We researched and developed hardware based peak-hold circuit that is able to detect peaks of gamma-ray signals through direct reading out their values by ADC at the time of maximum reaching for the small amplitude and high speed signals, and proposed and estimated its results in this paper. This peak-hold circuit is adequate to use in the radiation circumstances in which the gamma-rays are heavy because its circuit can catch high speed signals efficiently without software signal processing supports.

신동하 Dong-ha Shin , 김창복 Chang-bok Kim

DOI: JANT Vol.20(No.6) 617-624, 2016

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The hangul word embedding should be performed certainly process for noun extraction. Otherwise, it should be trained words that are not necessary, and it can not be derived efficient embedding results. In this paper, we propose model that can retrieve more efficiently by query language expansion using hangul word embedded, apriori, and text mining. The word embedding and apriori is a step expanding query language by extracting association words according to meaning and context for query language. The hangul text mining is a step of extracting similar answer and responding to the user using noun extraction, TF-IDF, and cosine similarity. The proposed model can improve accuracy of answer by learning the answer of specific domain and expanding high correlation query language. As future research, it needs to extract more correlation query language by analysis of user queries stored in database.

최현준 Hyunjun Choi

DOI: JANT Vol.20(No.6) 625-630, 2016

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Recently, various types of image contents are being produced, and interest in copyright protection technology is increasing. In this paper, we propose an image encryption technology for color images. This technique divides the image into RGB color components and then performs quad-tree decomposition based on the edge of image. After the quad-tree partitioning, encryption is performed on the selected blocks. Encryption is performed on color components to measure encryption efficiency, and encryption efficiency is measured even after reconstitution into a color image. The encryption efficiency uses a visual measurement method and an objective image quality evaluation method. The PSNR values were measured as 7~10 dB for color difference components and 16~19 dB for color images. The proposed image encryption technology will be used to protect copyright of various digital image contents in the future.

유영원 Young-won You , 김기원 Kee-won Kim , 전준철 Jun-cheol Jeon

DOI: JANT Vol.20(No.6) 631-637, 2016

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Quantum cellular automata (QCA) are one of the alternative technologies that can overcome the limits of complementary metal-oxide-semiconductor (CMOS) scaling. It consists of nano-scale cells and demands very low power consumption. Various circuits on QCA have been researched until these days, and in the middle of the researches, exclusive-OR (XOR) gates are used as error detection and recover. Typical XOR logic gates have a lack of scalable, many clock zones and crossover designs so that they are difficult to implement. In order to overcome these disadvantages, this paper proposes XOR design using majority gate reduced clock zone. The proposed design is compared and analysed to previous designs and is verified the performance.