• Korean Journal of Remote Sensing
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• v.38 no.6_1
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• pp.1445-1462
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• 2022

Compact Advanced Satellite 500-4 (CAS500-4), which is scheduled to be launched in 2025, is a mid-resolution satellite with a 5 m resolution developed for wide-area agriculture and forest observation. To utilize satellite images, it is important to establish a precision sensor model and establish accurate geometric information. Previous research reported that a precision sensor model could be automatically established through the process of matching ground control point (GCP) chips and satellite images. Therefore, to improve the geometric accuracy of satellite images, it is necessary to improve the GCP chip matching performance. This paper proposes an improved GCP chip matching scheme for improved precision sensor modeling of mid-resolution satellite images. When using high-resolution GCP chips for matching against mid-resolution satellite images, there are two major issues: handling the resolution difference between GCP chips and satellite images and finding the optimal quantity of GCP chips. To solve these issues, this study compared and analyzed chip matching performances according to various satellite image upsampling factors and various number of chips. RapidEye images with a resolution of 5m were used as mid-resolution satellite images. GCP chips were prepared from aerial orthographic images with a resolution of 0.25 m and satellite orthogonal images with a resolution of 0.5 m. Accuracy analysis was performed using manually extracted reference points. Experiment results show that upsampling factor of two and three significantly improved sensor model accuracy. They also show that the accuracy was maintained with reduced number of GCP chips of around 100. The results of the study confirmed the possibility of applying high-resolution GCP chips for automated precision sensor modeling of mid-resolution satellite images with improved accuracy. It is expected that the results of this study can be used to establish a precise sensor model for CAS500-4.

• Journal of Satellite, Information and Communications
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• v.10 no.2
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• pp.80-85
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• 2015

In this paper, we present, an indstrial RFID layered microstrip patch antenna is designed using an inset feed method in order to improve recognition rates in a long distance as tags are attached to metal object by improving a problem of feeding power in fabricating metal tags and reducing effects of metallic object. The inset feed shows a distinctive characteristic that has no separation between emitters and feed lines differing from a structure with the conventional inductive coupling feed. This structure makes possible to produce a type that presents a low antenna height and enables impedance coupling for tag chips. Although it shows a difficulty in the impedance coupling due to increases in the parasite capacitance between a ground plane and an emitter in an antenna according to decreases in the height of a tag antenna, it may become a merit in designing the tag antenna because the antenna impedance can be determined as an inductive manner if a shorted structure is used for feeding power. Therefore, in this paper the microstrip patch antenna is designed as a modified type and applies the inset feed in order to reduce effects of metallic objects where the antenna is be attached. Also, the antenna uses a multi-layer structure that includes a metal plate between radiator and ground instead of using a single layer.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.1
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• pp.34-41
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• 2003

As a channel of a DS-CDMA system is shared among several users, the receivers face the problem of MAI. Also the bandlimited channel leads to ISI. Both components are undesired, but unlike the additive noise process, which is usually completely unpredictable, their space-time structure helps to estimate and remove them. This paper investigates a DS-CDMA system with a fading multipath channel. The investigations have been separated into a channel estimation part and a reception part. In the estimation part of seperated two parts, the multipath parameters such as DOA and TOA are evaluated in this paper. In the part of receiver, we used these parameters and tested the performance of this receiver about space-time beamformers(Decorrelating, Match-Filter, Wiener-Hopf, Subspace-Based). To assess many different estimation techniques and beamformers, the simulation compared with theoretical values is performed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.167-171
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• 2002

As a channel of a DS-CDMA system is shared among several users, the receivers face the problem of MAI. Also the multipath scenario leads to ISI. Both components are undesired, but unlike the additive noise process, which is usually completely unpredictable, their space-time structure helps to estimate and remove them. This paper investigates a DS-CDMA system with a fading multipath channel. The investigations have been separated into a channel estimation part and a reception part. In the first part, the estimation of multipath parameters(DOA, TOA) are considered, space-time beamformers(Decorrelating, Match-Filter, Wiener-Hopf) are performed in the second part. To assess many different estimation techniques and beamformers, the simulation compared with theoretical values is performed.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05a
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• pp.687-690
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• 2003

지식 정보화 시대에 들어서면서부터 정보는 개인이나 일부 기관에 국한됨이 없이 중요시되고 있지만, 그 경계는 나날이 모호해지고 정보의 양은 급속하게 늘어가고 있는 것이 오늘날의 현실이다. 이러한 시대적 환경은 보안의 중요성이 크게 부각되어 생체인식 기술에 대한 관심을 높아지게 만들었다. 생체인식(Biometrics)분야 중에서도 지문 인식(Recognition)은 많은 연구가 이루어졌으나 개선할 점이 여전히 남아있다. 특히, 정확성 및 속도향상이라는 측면이 그렇다고 할 수 있겠다. 본 논문에서는 기존의 지문 인증(Authentication)시스템의 지문 영상(Image)의 식별 능력을 증가시키고 다수의 지문 영상에서도 좋은 결과를 가져올 수 있는 고유한 특징이 될 수 있는 요소들(Factor)을 추출하여 진보된 지문인식 시스템을 구현하는 것을 궁극적인 목표로 하고 있다. 따라서, 지금까지의 관련 연구를 바탕으로 지문 인식 시스템을 구현하는 것을 궁극적인 목표로 하고 있다. 따라서. 지금까지의 관련 연구를 바탕으로 지문 인식 시스템의 성능 향상을 위해서 핵심적인 minutiae reference point, 방향 정보의 추출 방법을 제안하고 인식의 종결부라고 할 수 있는 정합(matching)에 관에서 논한 다음, 마지막으로 결론 및 향후 과제로서 개선할 부분을 제시한다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6B
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• pp.583-596
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• 2006

Evaporation is an essential parameter in Global water-energy cycle and the variability of evaporation affects water resources planning and managements. In this study, the temporal variability of pan evaporation data was analyzed and trend analysis of the data using Mann-Kendall test. The relationships among evaporation and rainfall, air temperature, humidity, cloudness were analyzed. Even though the longterm trends of air temperature and rainfall increases, that of evaporation except Jinju and Yeosoo results decreases as worldwide observations. Results demonstrate that decrease of pan evaporation represents increase of terrestrial evaporation as Brutsaert and Parlange(1998)'s analysis.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.4
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• pp.271-277
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• 2018

Generating an epipolar image which is removed a y-parallax from an original image is an essential technique for creating a 3D stereoscopic model or producing a map. In epipolar image production, there is a method of generating epipolar images by estimating the relative orientation parameters after matching the extracted distinct points in two images and a method of generating epipolar images by using the baseline and rotation angles of the two images after determining the exterior orientation parameters In this study, it was proposed a methodology to generate epipolar images using direction cosine in the exterior orientation parameters of the input images, and a method to use the transformation matrix for easy calculation when converting from the original image to the epipolar image. The applicability of the proposed methodology was evaluated by using images taken from the fixed wing and rotary wing drones. As a result, it was found that epipolar images were generated regardless of the type of drones.

• Korean Journal of Construction Engineering and Management
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• v.10 no.1
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• pp.136-145
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• 2009

The objective of the Intelligent Excavation System (IES) is to recognize the work environment and produce work plan and automatically control the excavator through integrating sensor and robot technologies. This paper discusses one of the core technologies of IES development project, development of 3D work environment modeling. 3D laser scanner is used for 3-dimensional mathematical model that can be visualized in virtual space in 3D. This paper describes (1) how the most appropriate 3D imaging system has been chosen; (2) the development of user interface and customization of the s/w to control the scanner for IES project; (3) the development of the mobile station for the scanner; (4) and the algorithm for the automatic registration of laser scan segments for IES project. The development system has been tested on the construction field and lessons learned and future development requirements are suggested.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.6
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• pp.9-19
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• 1998

RAID technology that provides the disk I/O system with high performance and high availability is essential for OLTP server. This paper describes the design and implementation of the HIPSS RAID system that has been developed for the SPAX OLTP server. HIPSS has the following design objectives: high performance, high availability, standardization and modularization of external interface, and ease of maintenance. It guarantees high performance by providing 10 independent I/O channels, large data cache, and parity calculation engine. Hardware modularization of the host interface makes it easy to replace host interface hardware module. By providing dual power supply, dual array controller, and disk hot swapping, it provides the system with high availability Implementation of HIPSS and integration test on SPAX has been completed and performance measurement on HIPSS is now going on. In this paper, we provide the detail description for HIPSS system architecture and the implementation results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.867-869
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• 2012

FRUC(Frame Rate Up Conversion) is core techniques for higher quality terminals or low channel rate. For these applications, in this paper, we propose a block-based reliability evaluation method for FRUC techniques using bi-lateral symmetrical motion estimation. First, in order to measure the reliability, by introducing cost evaluation tools such as motion vector consistency as well as temporal matching and spatial matching characteristics and then by combining these tools, we propose an efficient method which arrange the blocks according to distortion size. Through several simulations, it is shown that the proposed method is very effective in finding the high distortion blocks. Furthermore, it is expected that the proposed method can be effectively utilized in FRUC techniques and Distributed Video Coding technologies.