• Journal of Advanced Navigation Technology
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• v.26 no.5
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• pp.358-364
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• 2022

The Inter Communication System for avionics is in charge of processing all voice signals that internal calls between Pilot and Co-pilot, internal calls between Pilots and Crews, external calls through communication equipment such as Ultra/Very High Frequency Receiver/Transmitter(U/VHF RT), audio signal monitoring for navigation and mission equipment such as VHF Omnidirectional Range/Instrument Landing System(VOR/ILS), Tactical Air Navigation(TACAN), audio signal output for voice recording to Flight Data Recorder(FDR) and Data Transfer System(DTS), and warning/caution audio signal generate about the status and threat of aircraft. Because Inter Communication System for avionics is sensitive to noise in the case of analog audio signals, a redundant design that can protect audio signal from electromagnetic noise inside/outside of aircraft is required for the mission of pilots and crews. In this paper, Normal/Back-up operation mode and redundancy design plan based on digital method for the redundancy of the digital Inter Communication System for avionics and manufacturing, verification results are described.

• Journal of Advanced Navigation Technology
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• v.26 no.5
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• pp.338-343
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• 2022

The Air Radio Station plays a role in creating skyways for aircraft and helping them fly safely through aviation mobile communication facilities (U/VHF transceivers) and various navigation safety facilities. It is necessary to remove large trees and weeds around the aircraft because accurate and safe signals must be provided without interruption. During the mowing work for the efficient management of landscaping facilities, there have been cases in which noise is introduced by Lawn Mower, which hinders control work. Accordingly, in order to analyze how mower affects air mobile communication facilities, the interference effect on air mobile communication facilities was analyzed for four types of mower, two-stroke, and battery type. As a result of the analysis, it was found that the two-stroke mower greatly affects air mobile communication facilities.

• Journal of Advanced Navigation Technology
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• v.28 no.1
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• pp.109-115
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• 2024

The Concept of Operations (ConOps) document issued by the Korean Government (K-UAM ConOps) for urban air mobility (UAM) services takes into account not only aviation voice communication but also the use of 4G and 5G mobile communication to support the initial phase of UAM services. This paper studies a methodology to establish communication performance requirements for UAM traffic management and presents the analyzed results for communication performance requirements. To accomplish this, the operational scenarios of UAM developmental stages outlined in the K-UAM ConOps and FAA ConOps are scrutinized, and the diverse messages that must be communicated among various stakeholders for effective UAM operations are identified. A draft of communication performance requirements is also calculated by considering packet sizes, transmission frequencies, acceptable latencies, and availability. The outcomes of this study are expected to stand as a pioneering effort in defining communication requirements for UAM services, providing a crucial foundation for future initiatives such as the design of dedicated communication networks for UAM and the determination of required frequency bandwidth.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.2
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• pp.128-139
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• 2017

Railway is one of the public transportation systems along with shipping and aviation. With the recent introduction of high speed train, its proportion is increasing rapidly, which results in the higher risk of catastrophic failures. The wheel bearing to support the train is one of the important components requiring higher reliability and safety in this aspect. Recently, many studies have been made under the name of prognostics and health management (PHM), for the purpose of fault diagnosis and failure prognosis of the bearing under operation. Among them, the most important step is to extract a feature that represents the fault status properly and is useful for accurate remaining life prediction. However, the conventional features have shown some limitations that make them less useful since they fluctuate over time even after the signal de-noising or do not show a distinct pattern of degradation which lack the monotonic trend over the cycles. In this study, a new method for feature extraction is proposed based on the observation of relative frequency energy shifting over the cycles, which is then converted into the feature using the information entropy. In order to demonstrate the method, traditional and new features are generated and compared using the bearing data named FEMTO which was provided by the FEMTO-ST institute for IEEE 2012 PHM Data Challenge competition.

• Journal of Aerospace System Engineering
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• v.17 no.6
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• pp.1-8
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• 2023

Research, such as developing alternative energy in the transportation field, including aviation, is being actively conducted to solve the issue of current climate change. Interest in ammonia fuel as a carbon free energy (CFE) source is increasing due to the ease of liquefaction and transportation and similarity in energy density to that of methanol. However, explosiveness and toxicity of ammonia make it difficult to handle. Therefore, in this study, stable ammonia production was attempted using relatively easy-to-handle urea water solution (UWS). High temperature steam was used to promote the hydrolysis of ammonia. In order to determine the causes for ammonia production below the theoretical equivalent ratio, it was suggested that there were not enough collisions to promote the hydrolysis based on the kinetic theory of gases. The hydrolysis of unreacted isocyanic acid (HNCO) was tested according to the change in water supply. As a result, an increased amount of ammonia produced was confirmed. The increased amount of ammonia produced in a certain section was dependent on the steam temperature and the flow rate of water supplied.

• Journal of Advanced Navigation Technology
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• v.4 no.2
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• pp.114-131
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• 2000

An airline should consider the number of seats or size of aircraft, when it composes fleet or selects a type of aircraft for some routes. There are two major factors considered for this choice problem under the assumption that the objectives of an airline is a profit maximization: the operating cost and revenue from the aircraft operated. This research tries to solve the problem of aircraft size selection by airline. The study applies four steps to get optimal choice of aircraft size: (1) cost analysis for the relationship between airline operation cost and aircraft size: (2) market share and revenue analysis: (3) flight segment-level analysis, based on the derived cost, demand and revenue functions: and (4) network-level analysis to see how airlines make choice of aircraft size systematically at a network level. An airline can accommodate the increasing air travel demand by either increasing operation frequency, or increasing aircraft size that is represented by seat capacity, or both. Airport runway capacity and productivity depend on the size of aircraft used at airport. This paper presents the understanding of how airlines make decisions on the size of aircraft to operate, how they will adjust their choices when airport capacity is constrained, and how public regulation such as policy for landing fees could influence airlines' aircraft choice.

• Journal of Satellite, Information and Communications
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• v.7 no.3
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• pp.99-104
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• 2012

The United States will proceed with the effort to modernize the GPS system, and one of its main content is to provide L5 signal. L5 will be transmitted in a radio band reserved exclusively for aviation safety services. And, L5, in combination with L1, will improve the position accuracy via ionospheric correction and robustness via signal redundancy. However, The acquisition processing time of L5 takes longer than that of L1 as the code length of L5 is 10 times longer than that of L1. To reduce this acquisition processing time, a higher number of correlators in the aquisition module should be used. However, there is a problem that this causes increase in the complexity of the correlator configuration and the computation power. So, in this paper, we propose L5 signal tracking scheme using tracking results in the GPS L1/L5 receiver. The proposed scheme could reduce the hardware complexity as the GPS L5 signal acquisition module is not needed, and provide fast and stable tracking of L5 signal by aiding L1 tracking results such as PRN, the code phase synchronization, and the Doppler frequency. The feasibility of the proposed scheme is demonstrated through simulation results.

• Journal of Distribution Science
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• v.11 no.10
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• pp.5-15
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• 2013

Purpose - With the increase in fervor to purchase luxury brands, new social problems have arisen, such as excessive preoccupation with luxury brands and high preference for forged luxury goods. Therefore, the issues related to luxury brands, termed "Luxury Syndrome," have emerged as an area of great interest for researchers and practitioners. However, previous studies neglect to categorize this preference for luxury brands. Therefore, this study aims to identify the different purchasing behaviors of consumers using the types of luxury brands preferences as parameters. Research design, data, and methodology - This study arranges a causal relationship model assuming that purchase behaviors positively (+) affect typified preference for luxury brands and purchase intentions. We administered a questionnaire survey to the purchasers who bought luxury brands from department stores to secure additional data necessary to verify the hypotheses in this study. We then processed the data using SPSS 19.0. We further analyzed the basic data using frequency and descriptive statistical analysis, and verified the measurement tools through feasibility and reliability analyses. Moreover, this study uses multiple regression analysis to verify the hypotheses. Further, this study tests the path effect between luxury brand purchase attitude and purchase behavior, with non-intrinsic preference and intrinsic preference as the mediating variables. Results - Based on the results, the impact of tendencies of conspicuous consumption and self-monitoring on non-intrinsic preference was significantly positive (+), while the impact of tendencies of pursuit of a reference group, conspicuous consumption, and self-monitoring on intrinsic preference and purchase intentions was significantly positive (+). Further, non-intrinsic and intrinsic preferences positively (+) influence purchase intentions and the impact of non-intrinsic preference took an absolute portion. However, the tendency of dependence on brands negatively (-) impacts purchase intentions. The results showed that self-monitoring and conspicuous consumption tendencies have greater effect on purchase intention, which is mediated by non-intrinsic preference. In contrast, reference group following tendency has a greater effect on purchase intention, which is mediated by intrinsic preference. Conclusions - Based on the results, the study verifies that the consumption of luxury brands in Korea has not yet entered the settling period. The tendency for conspicuous consumption and the tendency for pursuit of the reference group were relatively important aspects for the consumers who prefer luxury brands non-intrinsically and intrinsically, respectively. Especially, it was found that the purchase intentions for forged brands originate from the tendency to depend on brands. Based on these findings, this study suggests the measures to develop and mature the luxury brands market, and reinforce marketing performance at the three levels, that is, government, distributors, and manufacturers. The luxury brands manufacturers should devote themselves to the production and design of products to catch the attention of mature consumers of luxury brands. The luxury brands distributors should then raise the level of Customer Relationship Management (CRM) for opinion leaders. Finally, the Government should prepare effective policies for the development of luxury brands and provide a variety of economic support.

• Journal of Distribution Science
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• v.12 no.8
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• pp.103-112
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• 2014

Purpose - There have been local government systems since June 1955. Many local governments have made use of festivals for regional public relations and the achievement of competitiveness. This study analyzes effective components of local festivals. There has been extensive research in relation to variables such as participation motivation, satisfaction level, recall intention, royalty, and recommend purpose. However, as a variable factor, attachment to the participation motivation of a festival has been overlooked along with support level to a festival. This study has added new variables named "attachment to local society" and "support level," which are dependent variables. We will study the relationship of these two variables. Research design, data, and methodology - This study has devised a cause-and-effect relationship model, which deduces that local residents' participation motivation for the festival will have positive influence on the festival support level and satisfaction level. We circulated questionnaires to local residents to get the data required to prove the hypothesis. To analysis the data, we used SPSS 21.0, and accomplished basic analysis through the analysis of frequency as well as descriptive statistical analysis. Further, we verified our measurement tools through reliability analysis, and examined the research hypothesis through multiple regression analysis. Results - With regard to the festival satisfaction level, the variables of local society attachment, festival attraction, escaping from the daily life, and family harmony have influence upon a positive effect (+) in this order. Among them, the variable of local society attachment has the greatest influence. However, in respect of support level for the festival, only the variables of local society attachment and escaping from the daily life have a valid influence on the positive effect (+), and local society attachment has relatively greater influence. In addition, not only does the festival satisfaction level affect the support level for the festival in terms of positive effect, the influence is also far-reaching, which verifies the mediating effect. Conclusions - The result shows that the local residents' satisfaction level with the Yudalsan Mountain Spring Flower Festival is comparatively high, which is due to the local society attachment. It also shows that it is difficult to create support without local residents' attachment with their area. Consequently, this study insists that the Yudalsan Mountain Spring Flower Festival should exceed its limitation as just a village-level party, in order to become a remarkable and outstanding festival, and suggests three operational implications: macro-environmental development, task environment development, and internal operational environmental development. From the macro-environmental perspective, the constant development of local culture and local business is proposed. In the task environment perspective, a new functional development for the festival is proposed. From the internal operational environmental perspective, improvements in festival operation methods are proposed. If these weak points are addressed and resolved through a more detailed approach, it will be very helpful for local government systems to operate the festival.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.469-476
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• 2021

An electronic attack (EA) system is an essential weapon system for performing electronic warfare missions that contain signal tracking and jamming against multiple threats using electromagnetic waves, such as air defense radars, wireless command and communication networks, and guided missiles. The combat effectiveness can be maximized, and the survivability of militarily protecting combat power can be enhanced through EA mission operations, such as disabling the functions of multiple threats. The EA system can be used as a radio frequency jamming system to respond to drone attacks on the core infrastructure, such as airports, power plants, and communication broadcasting systems, in the civilian field. This study examined the criteria for classification according to the electronic attack missions of foreign EA systems based on an aviation platform. The foreign R&D trends by those criteria were investigated. Moreover, by analyzing the R&D trends of domestic EA systems and future battlefields in the domestic security environments, this paper proposes technological development plans of EA systems suitable for the future battlefield environments compared to the foreign R&D trends.