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Search Results: 1 - 10 of 53550 matches for " Yi Sun "
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Gallbladder carcinoma associated with anomalous union of pancreatobiliary ductal system  [PDF]
Sun Young Yi
Open Journal of Gastroenterology (OJGas) , 2013, DOI: 10.4236/ojgas.2013.34042
Abstract: A 64-year-old woman was admitted with mild right upper quadrant abdominal pain. Her physical examination revealed a moderately nourished female with normal vital sign and no evidence of jaundice or anemia. Preoperative diagnosis was choledochal cyst with anomalous union of pancreaticobiliary duct (AUPBD), long Y-shaped type and gallbladder (GB) cancer. An extended cholecystectomy, excision of the common bile duct and biliary diversion via Roux-en Y hepaticojejunostomy was performed. The gallbladder cancer showed invasion to perimuscular connective tissue and no extension beyond serosa. Twelve months after curative resection, the patient had no evidence of tumor recurrence.
Cause Analysis and Countermeasure of Gypsum Rain in Coal-fired Power Plants  [PDF]
Qizhen Liu, Yanjing Sun, Yi Sun
Journal of Environmental Protection (JEP) , 2013, DOI: 10.4236/jep.2013.41B001
Abstract: Focusing on the phenomenon of gypsum rain while wet desulphurization(WFGD) were adopted in coal fired power plant without GGH, the paper studied and put forward the solutions : (1) desulfurization facilities related equipment modification; (2) optimal operation of existing desulfurization facilities.
Simulation And Realization Of Wireless Emergency Communication System Of Digital Mine
sun yi
Modern Applied Science , 2010, DOI: 10.5539/mas.v4n4p91
Abstract: The key question of underwell disaster rescue is that the information of disaster place can not be collected and transported to the rescue base for the failure of normal communication equipment . A new wireless emergency communication has been introduced in this paper that a temporary wireless channel has been putted with repeaters of Wi-Fi ,the Wi-Fi end equipment with sensors to be treated as disaster place information collecters,then the disaster information can be transported with it.The wireless emergency communication system has been simulated used NS2. The result shows that the system performs well on delay time , jitter and stability. And it is suitable for the requirement of emergency communication after underwell disaster.
Black Hole - Never Forms, or Never Evaporates
Sun Yi
Physics , 2011, DOI: 10.1088/1475-7516/2011/01/031
Abstract: Many discussion about the black hole conundrums, such as singularity and information loss, suggested that there must be some essential irreconcilable conflict between quantum theory and classical gravity theory, which cannot be solved with any semiclassical quantized model of gravity, the only feasible way must be some complete unified quantum theory of gravity. In \cite{Vachaspati2007a}, the arguments indicate the possibility of an alternate outcome of gravitational collapse which avoids the information loss problem. In this paper, also with semiclassical analysis, it shows that so long as the mechanism of black hole evaporation satisfies a quite loose condition that the evaporation lifespan is finite for external observers, regardless of the detailed mechanism and process of evaporation, the conundrums above can be naturally avoided. This condition can be satisfied with Hawking-Unruh mechanism. Thus, the conflict between quantum theory and classical gravity theory may be not as serious as it seemed to be, the effectiveness of semiclassical methods might be underestimated. An exact universal solution with spherical symmetry of Einstein field equation has been derived in this paper. All possible solutions with spherical symmetry of Einstein field equation are its special cases. In addition, some problems of the Penrose diagram of an evaporating black hole first introduced by Hawking in 1975 \cite{Hawking1975} are clarified.
A Family of Likelihood Ascent Search Multiuser Detectors: an Upper Bound of Bit Error Rate and a Lower Bound of Asymptotic Multiuser Efficiency
Yi Sun
Mathematics , 2007,
Abstract: In this paper, the bit error performance of a family of likelihood ascent search (LAS) multiuser detectors is analyzed. An upper bound on the BER of any LAS detector is obtained by bounding the fixed point region with the worst initial detector. The concept of indecomposable errors developed by Verdu is applied to tighten the upper bound. In a special instance, the upper bound is reduced to that for all the local maximum likelihood detectors. The upper bound is comparable with that of the optimum detector obtained by Verdu. A lower bound on the asymptotic multiuser efficiency (AME) is then obtained. It is shown that there are nontrivial CDMA channels such that a LAS detector can achieve unit AME regardless of user number. The AME lower bound provides a means for further seeking a good set of spreading sequences and power distribution for spectral and power efficient CDMA.
A Family of Likelihood Ascent Search Multiuser Detectors: Approach to Single-User Performance via Quasi-Large Random Sequence CDMA
Yi Sun
Mathematics , 2007,
Abstract: Since Tse and Verdu proved that the global maximum likelihood (GML) detector achieves unit asymptotic multiuser efficiency (AME) in the limit of large random spreading (LRS) CDMA, no suboptimal detector has been found to achieve unit AME. In this letter, we obtain that the WSLAS detector with a linear per-bit complexity achieves unit AME in the LRS-CDMA with a channel load < 1/2 - 1/(4ln2) bits/s/Hz. For a practical system with any user number, a quasi LRS-CDMA is then proposed to approach the single-user performance in the high SNR regime.
Spectral efficiency and optimal medium access control of random access systems over large random spreading CDMA
Yi Sun
Mathematics , 2008,
Abstract: This paper analyzes the spectral efficiency as a function of medium access control (MAC) for large random spreading CDMA random access systems that employ a linear receiver. It is shown that located at higher than the physical layer, MAC along with spreading and power allocation can effectively perform spectral efficiency maximization and near-far mitigation.
Quasi-Large Sparse-Sequence CDMA: Approach to Single-User Bound by Linearly-Complex LAS Detectors
Yi Sun
Mathematics , 2008,
Abstract: We have proposed a quasi-large random-sequence (QLRS) CDMA where K users access a point through a common channel with spectral spreading factor N. Each bit is extended by a temporal spreading factor B and hopped on a BN-chip random sequence that is spread in time and frequency. Each user multiplexes and transmits B extended bits and the total channel load is alpha = K/N bits/s/Hz. The linearly-complex LAS detectors detect the transmitted bits. We have obtained that as B tends to infinity, if alpha < 1/2 - 1/(4ln2), each transmitted bit achieves the single-bit bound in BER in high SNR regime as if there was no interference bit. In simulation, when bit number BK >= 500, each bit can approach the single-bit bound for alpha as high as 1 bit/s/Hz. In this paper, we further propose the quasi-large sparse-sequence (QLSS) CDMA by replacing the dense sequence in QLRS-CDMA with sparse sequence. Simulation results show that when the nonzero chips are as few as 16, the BER is already near that of QLRS-CDMA while the complexity is significantly reduced due to sequence sparsity.
Finite dimensional representations of the rational Cherednik algebra for $G_4$
Yi Sun
Mathematics , 2009, DOI: 10.1016/j.jalgebra.2009.11.040
Abstract: In this paper, we study representations of the rational Cherednik algebra associated to the complex reflection group $G_4$. In particular, we classify the irreducible finite dimensional representations and compute their characters.
A new integral formula for Heckman-Opdam hypergeometric functions
Yi Sun
Mathematics , 2014, DOI: 10.1016/j.aim.2015.09.037
Abstract: We provide Harish-Chandra type formulas for the multivariate Bessel functions and Heckman-Opdam hypergeometric functions as representation-valued integrals over dressing orbits. Our expression is the quasi-classical limit of the realization of Macdonald polynomials as traces of intertwiners of quantum groups given by Etingof-Kirillov Jr. Integration over the Liouville tori of the Gelfand-Tsetlin integrable system and adjunction for higher Calogero-Moser Hamiltonians recovers and gives a new proof of the integral realization over Gelfand-Tsetlin polytopes which appeared in the recent work of Borodin-Gorin on the beta-Jacobi corners ensemble.
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