• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.9
• /
• pp.3889-3894
• /
• 2012

The platform of railroad station for domestic passenger train has been operated at two categories like the platforms if low level(500mm, mainline) and high level(1,135mm, metropolitan subway line). To operate both metropolitan subway line and mainline railroad safely, it is essential to develop the doorstep equipment of railway vehicle regardless of low and high level platforms. On the other hand, the domestic test standard at durability and reliability of doorstep equipment has not been existed until now. This study aims at the development on doorstep equipment of telescopic sliding type for low and high level platforms. Durability analysis with VPD(Virtual Product Development) techniques are performed and the durability standard & qualification life through the rig test during no failure test time is examined in accordance with reliability qualification test.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.46 no.7
• /
• pp.592-601
• /
• 2018

The GPS/INS integrated navigation system, which is one of the electronic equipments mounted on military aircraft store, can not directly receive GPS signals by the aircraft wing before the drop, so GPS navigation data is received from the aircraft and used for filter integration, afterwards, the integrated navigation is performed using the GPS information directly received through the antenna. In this case, it is possible to operate the mount in old aircraft without any modification of the aircraft when GPS data is transmitted using wireless. However, the delay occurs while the aircraft navigation data is transmitted to the integrated navigation filter of the aircraft store via wireless, which affects the time synchronization of the GPS measurement and the INS information, affecting the integrated navigation performance. In this paper, an algorithm to analyze and compensate the effect of generation and transmission delay that can occur when implementing GPS/INS integrated navigation system of aircraft store that receives GPS data via wireless.

• Journal of Korea Society of Industrial Information Systems
• /
• v.19 no.3
• /
• pp.31-39
• /
• 2014

In KSLV-I launch mission, real-time data from the tracking stations are acquired, processed and distributed by the Mission Control System to the user group who needed to monitor processed data for safety and flight monitoring purposes. The processed trajectory data by the mission control system is sent to each tracking system for target designation in case of tracking failure. Also, the processed data are used for decision making for flight termination when anomalies occur during flight of the launch vehicle. In this paper, we propose the processing mechanism of slaving data which plays a key role of launch vehicle tracking mission. The best position data is selected by predefined logic and current status after every available position data are acquired and pre-processed. And, the slaving data is distributed to each tracking stations through time delay is compensated by extrapolation. For the accurate processing, operation timing of every procesing modules are triggered by time-tick signal(25ms period) which is driven from UTC(Universial Time Coordinates) time. To evaluate the proposed method, we compared slaving data to the position data which received by tracking radar. The experiments show the average difference value is below 0.01 degree.

• Journal of Internet Computing and Services
• /
• v.6 no.5
• /
• pp.143-154
• /
• 2005

This paper presents a reliable multicast transmission for the advertising-supported Access Point in which a user can use a wireless network access service through receiving the advertisement. In this paper we propose a application-layer multicast protocol that controls a transmission rate of the mobile device for the reliable multicast in wireless LAN environment. Internet advertising includes all means and medias for advertising on the Internet in order to raise sales or popularity of the products or services. Since the current Internet advertising systems are passive, the target systems are exposed to unspecified persons and its exposure rates of the advertisement are changeable and unpredictable. In this paper, we propose an Internet advertising system, with which users can access the wireless Internet without charge, advertisers can provide customized advertisement according to location, time, and categories of users, and owners of network infrastructure can manage the system with a low cost.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.2
• /
• pp.39-47
• /
• 2020

The fire protection system for high-rise buildings is currently confined to the preparation of sprinklers, emergency stairs, and exit and monitoring systems. On the other hand, an integrated system, including the model with scenario-based actions, is required for effective fire protection. An integrated fire protection system is needed to operate and manage the total cycle of the fire protection. In this study, an integrated fire protection system, which included sensing and consequent processes related to fire emergencies, was designed and implemented. The designed scheme can gather and analyze the data of the production, operation, and consumption patterns as it integrates fire protection systems for fire fighters and evacuating people. The integrated fire protection technology and system, which has target performance with satisfied 1/2 sec transaction response time and 1.2 transactions per second, is expected to contribute to market creation in converged technology-based fire protection fields.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.38 no.1
• /
• pp.48-57
• /
• 2010

A comparison of two kinds of scheduling optimization algorithms is presented in this paper. As satellite control and operation techniques have been developed, satellite missions became more complicated and overall quantity of missions also increased. These changes require more specific consideration and a huge amount of computation for the satellite mission scheduling. Therefore, it is a good strategy to make a scheduling optimization algorithm for the efficient satellite mission scheduling operation. In this paper, two kinds of scheduling optimization algorithms are designed with tabu-search algorithm and genetic algorithm respectively. These algorithms are applied for the same mission scenario and the results of each algorithm are compared and analyzed.

• Journal of Advanced Navigation Technology
• /
• v.24 no.5
• /
• pp.329-342
• /
• 2020

In this paper, we analyzed the requirements for the application of UAM, a new concept to solve the traffic congestion in large cities. First, the current domestic and foreign status of research and development related to UAM was investigated and the pros and cons and the time required for each mission radius were analyzed for various configurations of aircraft being commercialized. In addition, in order to analyze the market acceptance of the UAM, the individual's consciousness and reliability requirements were identified and safety requirements were analyzed through accident rate data for each aircraft type. Because it operates in a densely populated urban area, requirement analyses on noise and exhaust, which are environmental factors that can affect the community were performed, and requirements related to aircraft performance, certification standards, and airworthiness standards of FAA and EASA were also analyzed.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.9
• /
• pp.5502-5512
• /
• 2014

Until recently, Integrated Logistics Support (ILS) focused mainly on the development and acquisition of supportability factors (maintenance planning, maintenance tools, support equipment, supply support, maintenance training, etc.). In the long term, supportability strategies and policies are needed in terms of LEAN-like cost reduction, efficiency in the field of weapon systems. This study first introduces the concept of Lean, theory of Lean Maintenance and suggests Lean maintenance framework, maintenance strategy for ILS. The case studies were analyzed in terms of the maintenance time, maintenance man-hours, maintenance cost for Lean PM in a radar system. The direction of LEAN on supportability in a weapon system is suggested.

• The Journal of the Acoustical Society of Korea
• /
• v.23 no.2
• /
• pp.125-133
• /
• 2004

Most of the way shape estimation method using reference sources assume that the reference sources are in the farfield. That is, the reference sources are assumed to be far from the array. However, in applications of the array with reference sources, the reference sources are not far from the way, so that in practical ocean environments, the conventional method using farfield source model fail to estimate the positions of the hydrophones. In this paper, based on the nearfield source model, a subspace-based array shape estimation method was proposed. In the proposed method, nearfield reference source is modeled using the differential time delay at each hydrophone, and nearfield parameters are derived. Using these parameters, a subspace-based array shape estimation method that generalizes the existing farfield subspace fitting method which can work regardless of the range of the source is proposed. The Cramer-Rao lower bound for the proposed method is investigated. The results of the numerical experiments indicate that the proposed method performs well in estimating the shape of a perturbed way regardless of the ranges of the reference sources.

• The Journal of the Korea Contents Association
• /
• v.9 no.2
• /
• pp.76-87
• /
• 2009

The growth of CPU and communication technologies have made an important contribution to the development of the network-based intelligent service robots. Robot software must guarantee the correct execution and safety of the user. To achieve this, it is highly required to research how to guarantee the QoS of the components which organize a robot software. The QoS of robot components aims to execute the component stably by processing the data stream in a correct way. By guaranteeing QoS, we can achieve the intelligence and stability of robots. In this paper, we design and implement the QoS framework to guarantee the QoS of robot components on robot platforms with limited resources. We also measure the response times of QoS requests and present the performance analysis results about it.