• Title/Summary/Keyword: DE (Difference Expansion)

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Distribution of Aortic Root Calcium in Relation to Frame Expansion and Paravalvular Leakage After Transcatheter Aortic Valve Implantation (TAVI): An Observational Study Using a Patient-specific Contrast Attenuation Coefficient for Calcium Definition and Independent Core Lab Analysis of Paravalvular Leakage

  • Nahid El Faquir;Quinten Wolff;Rafi Sakhi;Ben Ren;Zouhair Rahhab;Sander van Weenen;Patrick Geeve;Ricardo P J Budde;Eric Boersma;Joost Daemen;Nicolas M van Mieghem;Peter P de Jaegere
    • Journal of Cardiovascular Imaging
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    • v.30 no.4
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    • pp.292-304
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    • 2022
  • BACKGROUND: Calcium is a determinant of paravalvular leakage (PVL) after transcatheter aortic valve implantation (TAVI). This is based on a fixed contrast attenuation value while X-ray attenuation is patient-dependent and without considering frame expansion and PVL location. We examined the role of calcium in (site-specific) PVL after TAVI using a patient-specific contrast attenuation coefficient combined with frame expansion. METHODS: 57 patients were included with baseline CT, post-TAVI transthoracic echocardiography and rotational angiography (R-angio). Calcium load was assessed using a patient-specific contrast attenuation coefficient. Baseline CT and post-TAVI R-angio were fused to assess frame expansion. PVL was assessed by a core lab. RESULTS: Overall, the highest calcium load was at the non-coronary-cusp-region (NCR, 436 mm3) vs. the right-coronary-cusp-region (RCR, 233 mm3) and the left-coronary-cusp-region (LCR, 244 mm3), p < 0.001. Calcium load was higher in patients with vs. without PVL (1,137 vs. 742 mm3, p = 0.012) and was an independent predictor of PVL (odds ratio, 4.83, p = 0.004). PVL was seen most often in the LCR (39% vs. 21% [RCR] and 19% [NCR]). The degree of frame expansion was 71% at the NCR, 70% at the RCR and 74% at the LCR without difference between patients with or without PVL. CONCLUSIONS: Calcium load was higher in patients with PVL and was an independent predictor of PVL. While calcium was predominantly seen at the NCR, PVL was most often at the LCR. These findings indicate that in addition to calcium, specific anatomic features play a role in PVL after TAVI.

Improvement of Degradation Characteristics in a Large, Racetrack-shaped 2G HTS Coil for MW-class Rotating Machines

  • Park, Heui Joo;Kim, Yeong-chun;Moon, Heejong;Park, Minwon;Yu, Inkeun
    • Journal of Electrical Engineering and Technology
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    • v.13 no.3
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    • pp.1166-1172
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    • 2018
  • Degradation due to delamination occurs frequently in the high temperature superconductors (HTS) coil of rotating machines made with 2nd generation (2G) HTS wire, and the authors have observed other similar cases. Since an HTS field coil for a rotating machine is required to have stable current control and maintain a steady state, co-winding techniques for insulation material and epoxy resin for shape retention and heat transfer improvement are applied during coil fabrication. However, the most important limiting factor of this technique is delamination, which is known to be caused by the difference in thermal expansion between the epoxy resin and 2G HTS wire. Therefore, in this study, the experimental results of mixing the ratio of epoxy resin and alumina ($Al_2O3$) filler were applied to the fabrication of small and large test coils to solve the problem of degradation. For the verification of this scheme, eight prototypes of single pancake coils with different shapes were fabricated. They showed good results. The energization and operation maintenance tests of the stacked coils were carried out under liquid neon conditions similar to the operation temperature of an MW-class rotating machine. In conclusion, it was confirmed that the alumina powder mixed with epoxy resin in an appropriate ratio is an effective solution of de-lamination problem of 2G HTS coil.

$\pi$/4 shift QPSK with Trellis-Code in Rayleigh Fading Channel (레일레이 페이딩 채널에서 Trellis 부호를 적용한 $\pi$/4 shift QPSK)

  • 김종일;이한섭;강창언
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.3 no.2
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    • pp.30-38
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    • 1992
  • In this paper, in order to apply the $\pi$/4 shift QPSK to TCM, we propose the $\pi$/8 shift 8PSK modulation technique and the trellis-coded $\pi$/8 shift 8PSK performing signal set expansion and set partition by phase difference. In addition, the Viterbi decoder with branch metrics of the squared Euclidean distance of the first phase difference as well as the Lth phase difference is introduced in order to improve the bit error rate(BER) performance in differential detection of the trellis-coded $\pi$/8 shift 8 PSK. The proposed Viterbi decoder is conceptually the same as the sliding multiple de- tection by using the branch metric with first and Lth order phase difference. We investigate the performance of the uncoded .pi. /4 shift QPSK and the trellis-coded $\pi$/8 shift 8PSK with or without the Lth phase difference metric in an additive white Gaussian noise (AWGN) and Rayleigh fading channel using the Monte Carlo simulation. The study shows that the $\pi$/4 shift QPSK with the Trellis-code i. e. the trellis-coded $\pi$/8 shift 8PSK is an attractive scheme for power and bandlimited systems and especially, the Viterbi decoder with first and Lth phase difference metrics improves BER performance. Also, the next proposed algorithm can be used in the TC $\pi$/8 shift 8PSK as well as TC MDPSK.

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A Case Study of Shanghai Tang: How to Build a Chinese Luxury Brand

  • Heine, Klaus;Phan, Michel
    • Asia Marketing Journal
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    • v.15 no.1
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    • pp.1-22
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    • 2013
  • This case focuses on Shanghai Tang, the first truly Chinese luxury brand that appeals to both Westerners and, more recently, to Chinese consumers worldwide. A visionary and wealthy businessman Sir David Tang created this company from scratch in 1994 in Hong Kong. Its story, spanned over almost two decades, has been fascinating. It went from what best a Chinese brand could be in the eyes of Westerners who love the Chinese culture, to a nearly-bankrupted company in 1998, before being acquired by Richemont, the second largest luxury group in the world. Since then, its turnaround has been spectacular with a growing appeal among Chinese luxury consumers who represent the core segment of the luxury industry today. The main objective of this case study is to formally examine how Shanghai Tang overcame its downfall and re-emerged as one the very few well- known Chinese luxury brands. More specifically, this case highlights the ways with which Shanghai Tang made a transitional change from a brand for Westerners who love the Chinese culture, to a brand for both, Westerners who love the Chinese culture and Chinese who love luxury. A close examination reveals that Shanghai Tang has followed the brand identity concept that consists of two major components: functional and emotional. The functional component for developing a luxury brand concerns all product characteristics that will make a product 'luxurious' in the eyes of the consumer, such as premium quality of cachemire from Mongolia, Chinese silk, lacquer, finest leather, porcelain, and jade in the case of Shanghai Tang. The emotional component consists of non-functional symbolic meanings of a brand. The symbolic meaning marks the major difference between a premium and a luxury brand. In the case of Shanghai Tang, its symbolic meaning refers to the Chinese culture and the brand aims to represent the best of Chinese traditions and establish itself as "the ambassador of modern Chinese style". It touches the Chinese heritage and emotions. Shanghai Tang has reinvented the modern Chinese chic by drawing back to the stylish decadence of Shanghai in the 1930s, which was then called the "Paris of the East", and this is where the brand finds inspiration to create its own myth. Once the functional and emotional components assured, Shanghai Tang has gone through a four-stage development to become the first global Chinese luxury brand: introduction, deepening, expansion, and revitalization. Introduction: David Tang discovered a market gap and had a vision to launch the first Chinese luxury brand to the world. The key success drivers for the introduction and management of a Chinese luxury brand are a solid brand identity and, above all, a creative mind, an inspired person. This was David Tang then, and this is now Raphael Le Masne de Chermont, the current Executive Chairman. Shanghai Tang combines Chinese and Western elements, which it finds to be the most sustainable platform for drawing consumers. Deepening: A major objective of the next phase is to become recognized as a luxury brand and a fashion or design authority. For this purpose, Shanghai Tang has cooperated with other well-regarded luxury and lifestyle brands such as Puma and Swarovski. It also expanded its product lines from high-end custom-made garments to music CDs and restaurant. Expansion: After the opening of his first store in Hong Kong in 1994, David Tang went on to open his second store in New York City three years later. However this New York retail operation was a financial disaster. Barely nineteen months after the opening, the store was shut down and quietly relocated to a cheaper location of Madison Avenue. Despite this failure, Shanghai Tang products found numerous followers especially among Western tourists and became "souvenir-like" must-haves. However, despite its strong brand DNA, the brand did not generate enough repeated sales and over the years the company cumulated heavy debts and became unprofitable. Revitalizing: After its purchase by Richemont in 1998, Le Masne de Chermont was appointed to lead the company, reposition the brand and undertake some major strategic changes such as revising the "Shanghai Tang" designs to appeal not only to Westerners but also to Chinese consumers, and to open new stores around the world. Since then, Shanghai Tang has become synonymous to a modern Chinese luxury lifestyle brand.

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