• Journal of Positioning, Navigation, and Timing
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• v.7 no.1
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• pp.25-35
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• 2018

This paper describes the measurement of pulse positioning (input time) to calculate a time of arrival (TOA) that takes from transmitting a signal from the target of multilateration (MLAT) system to receiving the signal at the receiver. In this regard, this paper analyzes performances of simple threshold method and level adjust system (LAS) method, which is one of the adaptive threshold detector (ATD) methods, among many methods to calculate pulse positioning of signal received at the receiver. To this end, Cramer-rao lower bound (CRLB) with regard to pulse positioning, which was measured when signals transmitted from a transponder mounted at the target were received at the receiver, was induced and then deviation sizes with regard to pulse positioning, which was measured with simple threshold and LAS methods through MATLAB simulations, were compared. Next, problems occurring according to a difference in amplitude of signals inputted to each receiver are described when pulse positioning is measured at multiple receivers located at a different distance from the target as is the case in the MLAT system. Furthermore, LAS method to resolve the problems is explained. Lastly, this study analyzes whether a pulse positioning error occurring due to the signal noise satisfies the requirement (6 nsec. or lower) recommended for the MLAT system when using these two methods.

• Journal of the Korea Society of Computer and Information
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• v.25 no.5
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• pp.57-64
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• 2020

In this paper, based on the building's 3D modeling, a digital twin-based building control system using the collection information of wireless sensor box is proposed. The proposed system applies wireless sensors, making sensor modules more expandable and usable, and more intuitive building control possible through three-dimensional modeling. In addition, effective control and visual representation are possible through BIM data. Sensor boxes have been designed for general purpose so that a variety of sensor modules can be added and have been implemented for actual university buildings to demonstrate high availability. The results of this paper could be used to implement a digital twin control platform in the future.

• Journal of IKEEE
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• v.23 no.2
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• pp.502-507
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• 2019

We investigated theoretically the quantum optical transition properties of qusi 2-Dinensinal Landau splitting system, in Si. We apply the Quantum Transport theory (QTR) to the system in the confinement of electrons by square well confinement potential. We use the projected Liouville equation method with Equilibrium Average Projection Scheme (EAPS). In order to analyze the quantum transition, we compare the temperature and the magnetic field dependencies of the QTLW and the QTLS on two transition processes, namely, the phonon emission transition process and the phonon absorption transition process. Through the analysis of this work, we found the increasing properties of QTLW and QTLS of Si with the temperature and the magnetic fields. We also found the dominant scattering processes are the phonon emission transition process.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.10
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• pp.217-230
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• 2012

This paper propose interacting test programming methods between test equipment and hardware unit to verify function and performance of the hardware unit under test. Proposed test program can minimizes the risk of failures when the unit is mounted on the aircraft by testing and verifying the unit under the worst stress condition. Also, Object oriented design using UML make it easy to apply in other equipments. Test program consists of architecture package and hardware package. Architecture package is in a role for system management, log analysis, message receiving and message analysis. Messages that are used by system management define messages for testing and defined messages is sent and received to test equipment through Ethernet. Hardware package is in a role for hardware management that is needed to be tested and is related to a system. Hardware to be tested is divided into internal test and transmission test. Internal test inspects hardware itself and reports the test results to the test equipment. Transmission test inspects communication device by sending or receiving data. All kinds of test is done in the worst condition of the test unit executing in parallel. Each device is tested at least 482 times and at most 15,003 times about one hour. Test program is utilized in hardware reliability test like as environmental test or EMI test.

• Electronics and Telecommunications Trends
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• v.28 no.2
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• pp.20-28
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• 2013

항공기에서 소프트웨어가 차지하는 비중은 점점 늘어나는 추세이다. 항공 전자 시스템의 기능에 대한 요구는 점점 커지고 있으며 시스템의 복잡성을 증대시키고 있다. 이러한 추가되는 기능들로 인해 코드의 양이 늘어나고 있으며 이에 대한 비용이 증가하고 있다. 또한 컴퓨터, 센서, 디스플레이 등과 같은 항공 전자 시스템의 기술 영역들은 빠르게 성장하여 부피와 무게 및 에너지 소모 등의 비용은 줄어든 반면 성능은 크게 향상되었다. 이런 변화에 맞추어 항공 전자 시스템의 구조도 변화하고 있으며 탑재되는 항공용 운영체제도 그에 맞게 변화하고 있다. 항공용 운영체제에 필요한 기술과 최신 운영체제 현황에 대하여 소개한다.

• 한국항공운항학회:학술대회논문집
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• 2016.05a
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• pp.117-124
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• 2016

현행 국내 항공안전감독 업무 및 시스템의 인허가 AOC(Air Operator Certificate) 관련 정보 확인 기능 부재, 연 월간 감독계획 간의 연계성 취약, 점검 데이터 활용 통계 및 분석 기반 취약, 점검 및 인허가 대상별 인허가 점검 관련 데이터 관리 기반 미흡, 제한적 시스템 기능 구현에 따른 상당 업무기능의 수작업 문서처리 등의 한계점을 파악하고 이를 개선하기 위한 대안으로 위험관리(Risk Management) 기법을 활용한 항공안전감독 업무절차 및 현행 운영 시스템의 개선모형을 도출하고 이를 적용한 운영체계의 구현 방향성을 제시하고자 한다.

• Journal of Multimedia Information System
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• v.2 no.1
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• pp.179-186
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• 2015

This paper describes the application of a simulated annealing to a random signal-based learning. The simulated annealing is used to generate the reinforcement signal which is used in the random signal-based learning. Random signal-based learning is similar to the reinforcement learning of neural network. It is poor at hill-climbing, whereas simulated annealing has an ability of probabilistic hill-climbing. Therefore, hybridizing a random signal-based learning with the simulated annealing can produce better performance than before. The validity of the proposed algorithm is confirmed by applying it to two different examples. One is finding the minimum of the nonlinear function. And the other is the optimization of fuzzy control rules using inverted pendulum.

• Transactions on Control, Automation and Systems Engineering
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• v.1 no.1
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• pp.75-86
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• 1999

An air-data estimator for generic air-breathing hypersonic vehicles (AHSVs) is developed and demonstrated with an example vehicle configuration. The AHSV air-data estimation strategy emphasized improvement of the angle of attack estimate accuracy to a degree necessitated by the stringent operational requirements of the air-breathing propulsion. the resulting estimation problem involves highly nonlinear diffusion process (propagation); consequently, significant distortion of a posteriori conditional density is suspected. A simulation based statistical analysis tool is developed to characterize the nonlinear diffusion process. The statistical analysis results indicate that the diffusion process preserves the symmetry and unimodality of initial probability density shape state variables, and provide the basis for applicability of an Extended Kalman Filter (EKF). An EKF is designed for the AHSV air-data system and the air data estimation capabilities are demonstrated.

• Journal of the Korea Society of Computer and Information
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• v.23 no.4
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• pp.51-56
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• 2018

This paper proposes the efficient preprocessing method based on curvelet transform for edge enhancement in image. The propose method is generated the edge map by using the Canny algorithm to wavelet transform, which is the sub-step of the curvelet transform. In order to improve the part of edge feature, the selective sharpening according to the generate edge map is applied. In experimental result, the propose method achieves that the enhancement of edge feature is better than conventional methods. This leads that peak to signal noise ratio, edge intensity are improvement on average about 1.92, 1.12dB respectively.

• International Journal of Control, Automation, and Systems
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• v.5 no.3
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• pp.317-323
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• 2007

Quality of Service (QoS) in the Internet depends on queuing and sophisticated scheduling in routers. In this paper, we address the issue of managing traffic flows with different priorities. In our reference model, incoming packets are first classified based on their priority, placed into different queues with different capacities, and then multiplexed onto one router link. The fuzzy nature of the information on Internet traffic makes this problem particularly suited to fuzzy methodologies. We propose a new solution that employs a fuzzy inference system to dynamically and efficiently schedule these priority queues. The fuzzy rules are derived to minimize the selected Lyapunov function. Simulation experiments show that the proposed fuzzy scheduling algorithm outperforms the popular Weighted Round Robin (WRR) queue scheduling mechanism.