• Journal of the Korean Society for Aviation and Aeronautics
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• v.30 no.4
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• pp.9-22
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• 2022

With the continuous increase in demand for air transport services and the growth of the air transport industry, the International Civil Aviation Organization (ICAO) and its member states are facing social demands to expand the capacity of the air transport system and improve the efficiency of its operation. ICAO developed the concept of Performance Based Navigation (PBN) for the purpose of solving problems related to the function and performance of the navigation system. Member countries established an implementation plan in accordance with the resolutionof the ICAO General Assembly, and South Korea established a Performance-Based Navigation implementation plan in December 2009. This paper evaluates the progress made so far based on Korea's Performance-Based Navigation implementation plan and proposes a development direction for Performance-Based Navigation based on changes in the international environment.

• 한국항공운항학회:학술대회논문집
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• 2007.06a
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• pp.18-24
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• 2007

• Journal of Advanced Navigation Technology
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• v.16 no.3
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• pp.463-470
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• 2012

This paper proposes a new profit popularity-based segment caching control mechanism for assuring a consecutive streaming QoS (Quality of Service) in the wireless channel. Then, the proposed mechanism operates SSCP (Single Segment Caching Profit) and MSCP (Multiple Segment Caching Profit) for assuring a QoS. SSCP and MSCP is to optimize the cache performance when is performed the streaming in the proxy. The proposed mechanism simulated to evaluate such mechanisms as fixed-partition mechanism, weight-based mechanism, SSCP, and MSCP. Simulation results show that the proposed mechanism has superior performance compared to other mechanisms.

• Journal of Advanced Navigation Technology
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• v.11 no.1
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• pp.43-49
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• 2007

In this paper, the performance of OFDM/64QAM systems under Rummler model based cable channel is evaluated through computer simulation, and then the degree of performance improvement is estimated when adopting adaptive LMS equalizer. From the performance evaluation results, in the Rummler two-ray channel model, it is known that the performance improvement degree by adopting equalizer is greatly increased in case of attenuation coefficient of reflected ray (b) being less than 0.15, but when attenuation coeffcient (b) is larger than 0.15, the performance improvement degree by adopting equalizer shows little changes in almost all range of Eb/No.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.169.2-169.2
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• 2012

고기동 위성에 탑재된 GPS 수신기의 위성체의 기준 위치, 속도 및 시간의 정보를 제공한다. 특히 저궤도 관측위성은 빠른 동적 특성으로 인하여 GPS 위성 신호 획득 및 추적이 어려울 경우 연속적인 항행해를 제공하기 어려울 수 있다. 이를 위하여 위성 GPS 수신기는 지상용과 달리 넓은 대역폭의 신호 획득 및 추적이 가능한 RF수신단이 탑재되어 있으며 필터 기반의 궤도전파기가 탑재되어 있어 있다. 뿐만 아니라 GPS 수신기기의 상태 데이터 제공 및 고속 데이터 처리를 위하여 고성능 CPU가 탑재되어 있다. 특히 탑재된 궤도전파기는 고성능 필터 기반으로 설계되어 있으며 이를 이용하면 GPS 신호 추적이 되지 않은 상황에서도 비교적 정확하고 연속적인 항행해가 제공하게 된다. 본 논문에서는 저궤도 관측위성에 탑재된 GPS 수신기가 초기 위성운영에서 어떠한 절차에 의하여 동작이 되며 위성의 빠른 동적 특성에서 GPS 수신기의 가시성 및 추적 위성개수 분석 및 이를 바탕으로 위치 및 속도 정밀도가 어느 정도 되는지에 대한 성능 분석 결과를 정리 하였다. 본 논문 결과는 향후 고기동 위성의 GPS 수신기 및 관련 운영에 도움이 될 것으로 판단된다.

• Journal of Advanced Navigation Technology
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• v.14 no.6
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• pp.916-927
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• 2010

In this paper, we analyze the performance of the parity cache enabled RAID level-5 via the simulation. This RAID system consists of the DDR memory-based storage devices. To do this, we develop the simulation model and suggest the basic performance analysis data which we want to get via the simulation. And we implement the simulator based on the simulation model and execute the simulator. From the result of the simulation, we expect that the parity cache enabled RAID level-5 configured by the DDR memory based storage devices has the positive effectiveness to the enhancing of the storage system performance if the storage access patterns of applications are tuned.

• Journal of Advanced Navigation Technology
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• v.11 no.4
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• pp.401-407
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• 2007

This paper proposes the ethernet-based in-vehicle networking method for "body" and "multimedia" domains. The ethernet-based in-vehicle networking method should modify the topology and the layer 2 for traffic shaping. In this paper, we simulate the two ring networking systems, the Media Oriented Systems Transport (MOST) and the proposed system with the shaping by the network simulator 2 and evaluate each performance. In addition, we demonstrate the proposed networking system to exchange two kinds of traffic, i.e., QoS data and best-effort data, on the ring network constituting of three nodes. Finally this paper expects to substitute the ethernet-based in-vehicle network for the MOST in advance.

• Journal of Advanced Navigation Technology
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• v.16 no.3
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• pp.426-432
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• 2012

In this paper, we investigate the signal to noise ratio (SNR) estimation performance of Cross quadrature amplitude modulation (QAM), which is being used for asymmetric digital subscriber line (ADSL), very high bit rate digital subscriber line (VDSL), and digital video broadcasting - cable (DVB-C), and has been found to be useful in adaptive modulation and blind equalization. At first, the symbol error rate (SER) performance of Cross QAM is analyzed in Rayleigh fading channel. Then we suggest error vector magnitude (EVM) based SNR estimation utilizing the selected constellation points having different types of decision region from one another, and verify that SNR estimation performance of each points have different performance pattern through simulation. From the simulation results, it has been found that when suggested selected constellation points are used for SNR estimation in Cross QAM, estimation performance is enhanced in additive white Gaussian noise (AWGN) channel or Ricean fading channel.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.189-192
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• 2014

Recently, U.S. and Europe, which are advanced to Air Traffic Control Management, are interest in replacing Radar System with Communications, Navigation and Surveillance(CNS) and Air Traffic Management(ATM). They pursue to research the efficient Air Traffic Control Management. This paper covers ADS-B 1090ES system which is one of CNS/ATM surveillance systems. This research satisfied all performance required by RTCA DO-268B and EUROCAE ED-129. It optimized algorism to mainly enhance performance such as quality of receiver signal, dynamic range, and so on. The optimized mechanism provided stable performance of demodulation, tuned the level of signal, and had reduced the false reception ratio by the signal level difference. The analyzed algorism helped great performance and will be considered to apply broad system applications.

• Journal of Advanced Navigation Technology
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• v.14 no.5
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• pp.752-759
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• 2010

In this paper, we propose differential-logging method to improve the performance of RMW(Read Modify Write) operations of DDR-SSD based software RAID. Small writes that are frequently occurred in enterprise applications are main factor to degrade the performance of RAID5. Once a block is updated in RAID5, the parity block of the block must be updated to maintain consistency of parity. Therefore, to process a small write request, we need to read its parity block stored in disk, read old data, perform XOR operation, and write updated data and parity block. Several methods for hard disk based software RAID are proposed to solve the small write problems in RAID 5. Ln this paper, we propose a differential-logging method which carefully considers the DDR-SSD to solve the small write problem in RAID 5. We show that our proposed method out performs the existing software RAID in LINUX through simulations.