• Title/Summary/Keyword: Chang

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Security Analysis and Improvements of a Biometrics-based User Authentication Scheme Using Smart Cards (스마트 카드를 이용한 생체인식 기반 사용자 인증 스킴의 안전성 분석 및 개선)

  • An, Young-Hwa
    • Journal of the Korea Society of Computer and Information
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    • v.17 no.2
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    • pp.159-166
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    • 2012
  • Many biometrics-based user authentication schemes using smart cards have been proposed to improve the security weaknesses in user authentication system. In 2010, Chang et al. proposed an improved biometrics-based user authentication scheme without concurrency system which can withstand forgery attack, off-line password guessing attack, replay attack, etc. In this paper, we analyze the security weaknesses of Chang et al.'s scheme and we have shown that Chang et al.'s scheme is still insecure against man-in-the-middle attack, off-line biometrics guessing attack, and does not provide mutual authentication between the user and the server. And we proposed the improved scheme to overcome these security weaknesses, even if the secret information stored in the smart card is revealed. As a result, the proposed scheme is secure for the user authentication attack, the server masquerading attack, the man-in-the-middle attack, and the off-line biometrics guessing attack, does provide the mutual authentication between the user and the remote server. And, in terms of computational complexities, the proposed scheme is more effective than Chang et al.'s scheme.

Computed tomographic analysis of maxillary sinus anatomy relevant to sinus lift procedures in edentulous ridges in Taiwanese patients

  • Yu, Shun-Jen;Lee, Yi-Hao;Lin, Ching-Ping;Wu, Aaron Yu-Jen
    • Journal of Periodontal and Implant Science
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    • v.49 no.4
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    • pp.237-247
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    • 2019
  • Purpose: To analyze the maxillary sinus anatomy over edentulous ridges in the bilateral posterior maxillary area in Taiwanese patients using cone-beam computed tomography (CBCT). Methods: In total, 101 anatomical sites from 61 patients, including 32 premolar and 69 molar regions, were analyzed using CBCT. Measurements were made of the width and height of edentulous ridges, the thickness of the lateral wall of the maxillary sinus, and the presence of a sinus septum and the posterior superior alveolar artery (PSAA). A statistical analysis of the measurements was performed, and correlations among the measurements were assessed. Results: The average ridge width was $10.26{\pm}3.16mm$, with a significantly greater ridge width in the second molar region than in the premolar region. The mean residual ridge height was $8.55{\pm}4.09mm$, and ridge height showed an opposite trend from ridge width for the premolar and molar regions. A sinus septum was present at 5.9% of the sites, and the PSAA was observed in 24.5%. The average thickness of the lateral wall of the maxillary sinus was $2.08{\pm}0.94mm$, with no significant difference between the tooth position and lateral wall thickness. Conclusions: This study presents the anatomical features of the maxillary sinus, which should be considered in sinus lift procedures for implant placement, in the Taiwanese population. The use of CBCT is recommended to avoid intraoperative complications.

Transcutaneous medial fixation sutures for free flap inset after robot-assisted nipple-sparing mastectomy

  • Kim, Bong-Sung;Kuo, Wen-Ling;Cheong, David Chon-Fok;Lindenblatt, Nicole;Huang, Jung-Ju
    • Archives of Plastic Surgery
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    • v.49 no.1
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    • pp.29-33
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    • 2022
  • The application of minimal invasive mastectomy has allowed surgeons to perform nipples-paring mastectomy via a shorter, inconspicuous incision under clear vision and with more precise hemostasis. However, it poses new challenges in microsurgical breast reconstruction, such as vascular anastomosis and flap insetting, which are considerably more difficult to perform through the shorter incision on the lateral breast border. We propose an innovative technique of transcutaneous medial fixation sutures to help in flap insetting and creating and maintaining the medial breast border. The sutures are placed after mastectomy and before flap transfer. Three 4-0 nylon suture loops are placed transcutaneously and into the pocket at the markings of the preferred lower medial border of the reconstructed breast. After microvascular anastomosis and temporary shaping of the flap on top of the mastectomy skin, the three corresponding points for the sutures are identified. The three nylon loops are then sutured to the dermis of the corresponding medial point of the flap. The flap is placed into the pocket by a simultaneous gentle pull on the three sutures and a combined lateral push. The stitches are then tied and buried after completion of flap inset.

Exhibition of Wild Animals (야생동물의 전시)

  • Moon Hong Sik;Oh Chang Young
    • Journal of the korean veterinary medical association
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    • v.14 no.1
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    • pp.51-56
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    • 1978
  • The older zoos were parks with fenced enclosures and buildings containing caged animals. But animals in bare cages are not very the natural environment in which an animal or a group of animals is found. In some displays, the animals appear to be living to

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The development and current status regard to Sijo-chang時調唱 (시조창(時調唱)의 전개(展開)와 현황(現況))

  • Moon, Hyun
    • Sijohaknonchong
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    • v.42
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    • pp.29-68
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    • 2015
  • This article focused on the development and current status of Sijo-chang, the Korean classical vocal genre, which is the text as a fixed form of Korean classical poems. Historically, Sijo-chang has originally emerged from Hyangga鄕歌 during Silla period (BC. 57- AD. 935). However, the current Sijo-chang has been developed from the latter of Joseon朝鮮 period(AD. 1392-1910) in 1800s. Since 1800s, Sijo-chang derived from the Gyeong-je Pyeong sijo京制 平時調, which was established in Seoul, was able to accelerate its musical types and regional characteristics among the Korean peninsula. By setting a clear division of two time periods between 1800s and those periods since 1900s to today, this article mainly explains how Sijo-chang has been developed historically. First of all, in order to appraise the musical styles and characteristics of Sijo-chang in 1800s, comparing the current musical types of Sijo-chang and those printed old score books which has its historical musical characteristics during 1800s is necessary. Secondly, this paper concentrated on the transmitted lineages of representative vocalists among the regional-based Sijo-chang from 1900s to today. During those periods, the Sijo-chang has formed its particular regional-based musical characteristics among the Korean peninsula such as Yeong-je嶺制 of Gyeongsang province慶尙道, Naepo-je內浦制 of Chungcheong province忠淸道 and Wan-je完制 of Cheolla province全羅道. Although it was not a type of regional-based Sijo-chang, as a creation with reference based on certain regional types of Sijo-chang in 1960s, this paper introduced the inheritance process of Seogam-je石菴制 which was made by Jung Gyeong-tae鄭坰兌 named Seogam石菴 as his pen name. Since Seogam-je has been singing as the most influential musical types of Sijo-chang through the mainly southern region of Korean peninsula and even in Seoul, it was highly significant to research it. In addition, this paper elaborately highlighted the developments of various Sijo-chang based on its historical performances, studies, and the composed pieces from the early 1900s or the mid-1900s. In conclusion, in order to set a vigorous development of Sijo-chang, this paper raised several concerns among the future of Sijo-Chang and the significance of its traditional value.

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A Study on Optimum Acceleration Profile to Reduce Vibration of PMLSM (PMLSM의 진동저감을 위한 최적의 속도 프로파일일 관한 연구)

  • Lee, Dong-Yeup;Yoon, Kang-Jun;Jung, Chun-Gil;Kim, Gyu-Tak;Choi, Yong-Hyu
    • Proceedings of the KIEE Conference
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    • 2004.10a
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    • pp.98-100
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    • 2004
  • This paper is proposed vibration minimize method of PMLSM which is designed to minimize detent force. To minimize of vibration at acceleration discontinuous point of velocity curve, genetic algorithm is applied. The vibration characteristic is compared general trapezoid velocity curve with proposed velocity profile.

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RC Short Column Effects on Seismic Performance of Small-Sized Buildings in Korea (국내 소규모 건축물의 단주효과에 대한 내진성능검토)

  • Kim, Kyungtae;Yoo, Chang-Hwan;Park, Kyunghoon;Kim, Taejin
    • Journal of the Earthquake Engineering Society of Korea
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    • v.20 no.7_spc
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    • pp.545-551
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    • 2016
  • This paper investigates seismic performance of a small-sized single story building in Korea. Nonlinear pushover anlaysis is performed to verify shear failure of RC short columns eventually led to performance degradation. Also, nonlinear time history analysis is performed using the same earthquakes from Gyeongju. Similar failure mode was obtained as in the report where a sudden rupture of the RC columns happened.