• Title/Summary/Keyword: Requirement uncertainty

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A Comparison of Pan-sharpening Algorithms for GK-2A Satellite Imagery (천리안위성 2A호 위성영상을 위한 영상융합기법의 비교평가)

  • Lee, Soobong;Choi, Jaewan
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.40 no.4
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    • pp.275-292
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    • 2022
  • In order to detect climate changes using satellite imagery, the GCOS (Global Climate Observing System) defines requirements such as spatio-temporal resolution, stability by the time change, and uncertainty. Due to limitation of GK-2A sensor performance, the level-2 products can not satisfy the requirement, especially for spatial resolution. In this paper, we found the optimal pan-sharpening algorithm for GK-2A products. The six pan-sharpening methods included in CS (Component Substitution), MRA (Multi-Resolution Analysis), VO (Variational Optimization), and DL (Deep Learning) were used. In the case of DL, the synthesis property based method was used to generate training dataset. The process of synthesis property is that pan-sharpening model is applied with Pan (Panchromatic) and MS (Multispectral) images with reduced spatial resolution, and fused image is compared with the original MS image. In the synthesis property based method, fused image with desire level for user can be produced only when the geometric characteristics between the PAN with reduced spatial resolution and MS image are similar. However, since the dissimilarity exists, RD (Random Down-sampling) was additionally used as a way to minimize it. Among the pan-sharpening methods, PSGAN was applied with RD (PSGAN_RD). The fused images are qualitatively and quantitatively validated with consistency property and the synthesis property. As validation result, the GSA algorithm performs well in the evaluation index representing spatial characteristics. In the case of spectral characteristics, the PSGAN_RD has the best accuracy with the original MS image. Therefore, in consideration of spatial and spectral characteristics of fused image, we found that PSGAN_RD is suitable for GK-2A products.

Policy of Surging Investment to Early Startups Via Boosting up SAFE in Korea (창업초기투자 촉진을 위한 한국형 SAFE 활성화 방안에 대한 연구)

  • Park, Jin;Yang, Youngseok
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.17 no.6
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    • pp.1-12
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    • 2022
  • This paper put the goal on boosting up early startup investment by delivering and positioning SAFE as the main early startup investment type in Korea. In particular, this paper proves the better fitting of SAFE as to the early stage of venture investment than these of Convertible Note. This paper as referring the previous studies of SAFE as the major keystone issues determining active SAFE applying (legal positioning issue, tax treatment issue, failure of inducing the following investment with uncertainty over maturity) proposes boosting up policy of Korean SAFE. First, as to accounting treatment of SAFE, it suggests SAFE to recognize legally as "the capital" on the Korean Venture Investment Act of introducing SAFE actively as venture investment type. Second, as to tax treatment issue, it proposes on amending venture indication rule as the best alternative of resolving tax issue by accepting SAFE as the investment meeting to venture investment requirement. Third, as benchmarking foreign cases, it delivers the method of modifying foreign SAFE Contract Format by adding up more clauses about safety vehicles against the failure of the following investment and fixing maturity date and event. Ultimately, all resolutions of this paper fall on highlighting the role of Korean Venture Investment Act and Ministry of SMEs and Startups.