Hybrid beamforming for single carrier mmWave MIMO systems

Hybrid analog and digital beamforming (HBF) has been recognized as an attractive technique offering a tradeoff between hardware implementation limitation and system performance for future broadband millimeter wave (mmWave) communications. In contrast to most current works focusing on the HBF design for orthogonal frequency division multiplexing based mmWave systems, this paper investigates the HBF design for single carrier (SC) systems due to the advantage of low peak-to-average power ratio in transmissions. By applying the alternating minimization method, we propose an efficient HBF scheme based on the minimum mean square error criterion. Simulation results show that the proposed scheme outperforms the conventional HBF scheme for SC systems.Comment: IEEE GlobalSIP2018, Feb. 201

Molecular and Pathological Analyses of Three New Mouse Mutations That Affect Ear Development and Function

This dissertation presents three new mouse models that help to study the functions of Enpp1, Atp6v1b1, and Tbx1 for ear development and function. asj (aging with stiffened joints) carries a missense mutation in the mouse Enpp1 gene. Enpp1 encodes the enzyme ENPP1 that regulate soft-tissue calcification and bone mineralization, and is associated with generalized arterial calcification of infancy and hypophosphatemic rickets in human patients. asj mutant mice show severe middle ear infection and tissue calcification, which provide a new mouse model to study otitis media and tympanoscleorosis. Atp6v1b1 encode a protein that is a subunit of the V-ATPase pump, which is the key regulator of pH homeostasis. Atp6v1b1 mutation is associated with human distal renal tubular acidosis (dRTA) with hearing loss; however, Atp6v1b1 knockout mice have mild kidney phenotype and normal hearing. vtx (vortex) mice carry a missense mutation in the mouse Atp6v1b1 gene on a MRL.Mpj background, that shows severe hearing loss and vestibular dysfunction. Transfer the vtx mutation to a B6 background did not cause hearing loss, indicating genetic background effects underlie this variation. We performed linkage backcross to map the genetic loci that modify the degree of hearing loss on the two different background strains and found statistically significant linkage with a region on Chr13. Because MRL-vtx mice exhibit enlargements of the endolymphatic sac and duct in the inner ear but do not exhibit the overt metabolic acidosis characteristic of dRTA, they provide a new genetic model for nonsyndromic deafness with enlarged vestibular aqueducts. TBX1 haploinsufficieny is associated with human DiGeorge syndrome. Tbx1 knockout mice are embryonic lethal and ear morphogenesis stops around E10 in the mutant mice. Study showed expression of TBX1 in the stria vascularis and vestibular dark cells, but because Tbx1 KO mice don’t have fully developed inner ear, new model is required to study Tbx1 function at later development stage. Tbx1wdml (windmill) mice carry a missense mutation in the mouse Tbx1 gene and have fully developed inner ear. Hearing loss and vestibular dysfunction correlate well with TBX1 expression in the stria vascularis and dark cells. This new Tbx1 mouse model provides a valuable tool to study Tbx1 function in the development of stria vascularis and semicircular canal

Constraints on the Dark Side of the Universe and Observational Hubble Parameter Data

This paper is a review on the observational Hubble parameter data that have gained increasing attention in recent years for their illuminating power on the dark side of the universe --- the dark matter, dark energy, and the dark age. Currently, there are two major methods of independent observational H(z) measurement, which we summarize as the "differential age method" and the "radial BAO size method". Starting with fundamental cosmological notions such as the spacetime coordinates in an expanding universe, we present the basic principles behind the two methods. We further review the two methods in greater detail, including the source of errors. We show how the observational H(z) data presents itself as a useful tool in the study of cosmological models and parameter constraint, and we also discuss several issues associated with their applications. Finally, we point the reader to a future prospect of upcoming observation programs that will lead to some major improvements in the quality of observational H(z) data.Comment: 20 pages, 6 figures, and 1 table, uses REVTeX 4.1. Review article, accepted by Advances in Astronom

Multilevel Diversity Coding with Secure Regeneration: Separate Coding Achieves the MBR Point

The problem of multilevel diversity coding with secure regeneration (MDC-SR) is considered, which includes the problems of multilevel diversity coding with regeneration (MDC-R) and secure regenerating code (SRC) as special cases. Two outer bounds are established, showing that separate coding of different messages using the respective SRCs can achieve the minimum-bandwidth-regeneration (MBR) point of the achievable normalized storage-capacity repair-bandwidth tradeoff regions for the general MDC-SR problem. The core of the new converse results is an exchange lemma, which can be established using Han's subset inequality