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Search Results: 1 - 10 of 29361 matches for " Xin Zeng "
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Statistical Modeling of Antenna: Urban Equipment Interactions for LTE Access Points
Xin Zeng,Alain Sibille
International Journal of Antennas and Propagation , 2012, DOI: 10.1155/2012/292018
Abstract: The latest standards for wireless networks such as LTE are essentially based on small cells in order to achieve a large network capacity. This applies for antennas to be deployed at street level or even within buildings. However, antennas are commonly designed, simulated, and measured in ideal conditions, which is not the real situation for most applications where antennas are often deployed in proximity to objects acting as disturbers. In this paper, three conventional wireless access point scenarios (antenna-wall, antenna-shelter, and antenna lamppost) are investigated for directional or omnidirectional antennas. The paper first addresses the definition of three performance indicators for such scenarios and secondly uses such parameters towards the statistical analysis of the interactions between the wall and the antennas. 1. Introduction With the development of new wireless communication systems and standards, antennas of base stations or access points are more likely deployed at street level in proximity to walls and urban furniture other than the traditional antennas for GSM networks which are mounted on rooftops with few neighboring disturbers [1–3]. The effect of surrounding disturbers may be strong or weak and is very sensitive to the antenna location and antenna characteristics. Unfortunately, antennas are commonly designed, simulated, and measured in isolation from anything else as much as possible, which is not a realistic use case. For instance, the radiation pattern of a dipole mounted beside a wall is highly perturbed, indicating the severe performance degradation to omnidirectionality (see below). Unfortunately, such disturbances are highly variable and impact the behavior of antennas in an uneasily predictable manner, with significant consequences in terms of cell coverage. The latter can be quantitatively evaluated through, for example, ray tracing of even empirical propagation simulation tools, but it will be very costly to compute the propagation for many realizations of disturbed antenna characteristics. For this reason, a reasonable approach is first to develop a statistical model for the antenna radiation behavior, before combining it with a model of simulation of the propagation. It is the goal of this paper, keeping in mind that statistical models lend themselves to the tuning of the trade-off between complexity and accuracy, depending on the number of parameters involved in the statistical distributions. For instance, [4] gives an example of this approach through radiation patterns series expansions. Actually, the evaluation of
N′-(4-Methoxybenzylidene)-4-methylbenzohydrazide
Zeng-Xin Liu
Acta Crystallographica Section E , 2011, DOI: 10.1107/s1600536811049932
Abstract: The title compound, C16H16N2O2, is the product of the reaction of 4-methoxybenzaldehyde and 4-methylbenzohydrazide. The dihedral angle between the substituted benzene rings is 17.6 (3)° and the methoxy C atom is almost coplanar with its attached ring [deviation = 0.019 (4) ]. In the crystal, molecules are linked by N—H...O hydrogen bonds, forming C(4) chains propagating along the b-axis direction.
N′-(2-Hydroxybenzylidene)-3-methylbenzohydrazide
Zeng-Xin Liu
Acta Crystallographica Section E , 2011, DOI: 10.1107/s1600536811049944
Abstract: The title compound, C15H14N2O2, is the product of the reaction of 2-hydroxybenzaldehyde and 3-methylbenzohydrazide. The dihedral angle between the substituted benzene rings is 19.5 (3)° and an intramolecular O—H...N hydrogen bond generates an S(6) ring motif. In the crystal, molecules are linked by N—H...O hydrogen bonds to generate C(4) chains propagating in [001] and C—H...O interactions to the same O-atom acceptor reinforce the chains.
On Farmer’s Willingness to Small Forest Tenure Mortgage Loans —A Case Study on Yibin of Sichuan
Xin Cai,Weizhong Zeng
International Journal of Business and Management , 2011, DOI: 10.5539/ijbm.v6n3p272
Abstract: Based on the survey data of 364 peasant households in Yibin, Sichuan, this paper analyzes the farmer’s willingness to small forest tenure mortgage loans. The result indicates a high willingness up to 74.2%, i.e. the farmers are willing to invest forest tenure mortgage loans into forestry and agricultural production. The influential factors on farmer’s willingness to small forest tenure mortgage loans include age, education, forest area, the main source of family income, perception on the policies of forest tenure mortgage loans, social services of forestry, financial institutions, etc. We propose the policy advocacy of forest tenure mortgage loans be enhanced, mortgage loans of different period be designed for different purposes, and discount policy on small mortgage loans be issued.
Intensity process and compensator: A new filtration expansion approach and the Jeulin--Yor theorem
Xin Guo,Yan Zeng
Mathematics , 2008, DOI: 10.1214/07-AAP447
Abstract: Let $(X_t)_{t\ge0}$ be a continuous-time, time-homogeneous strong Markov process with possible jumps and let $\tau$ be its first hitting time of a Borel subset of the state space. Suppose $X$ is sampled at random times and suppose also that $X$ has not hit the Borel set by time $t$. What is the intensity process of $\tau$ based on this information? This question from credit risk encompasses basic mathematical problems concerning the existence of an intensity process and filtration expansions, as well as some conceptual issues for credit risk. By revisiting and extending the famous Jeulin--Yor [Lecture Notes in Math. 649 (1978) 78--97] result regarding compensators under a general filtration expansion framework, a novel computation methodology for the intensity process of a stopping time is proposed. En route, an analogous characterization result for martingales of Jacod and Skorohod [Lecture Notes in Math. 1583 (1994) 21--35] under local jumping filtration is derived.
On quasi-periodic solutions of the discrete Chen-Lee-Liu hierarchy
Xianguo Geng,Xin Zeng
Mathematics , 2013,
Abstract: Resorting to the Lax matrix and elliptic variables, the discrete Chen-Lee-Liu hierarchy is decomposed into solvable ordinary differential equations. Based on the theory of algebraic curve, the continuous flow and discrete flow related to the discrete Chen-Lee-Liu hierarchy are straightened under the Abel-Jacobi coordinates. The meromorphic function $\phi$, the Baker-Akhiezer vector $\bar\psi $ and the hyperelliptic curve $\mathcal{K}_N$ are introduced, by which quasi-periodic solutions of the discrete Chen-Lee-Liu hierarchy are constructed according to the asymptotic properties and the algebro-geometric characters of $\phi,\ \bar\psi $ and $\mathcal{K}_N$.
A New Immunofluorescence Assay for Fecal Calprotectin Distinguishes Inflammatory Bowel Disease from Functional Bowel Disease  [PDF]
Lixia Xu, Peisi Rao, Xin Liu, Zhirong Zeng
Open Journal of Gastroenterology (OJGas) , 2018, DOI: 10.4236/ojgas.2018.811042
Abstract: Aims: To investigate the diagnostic value of fecal calprotectin (FC) determined by a new immunofluorescence assay-fluorescence enzyme immunoassay (FEIA) in patient with inflammatory bowel disease (IBD) or functional bowel disease, compared with the typical ELISA kit. Methods: FC was determined simultaneously by FEIA and an ELISA kit in 26 patients with functional bowel disease and 77 patients with IBD. We compared the difference of FC levels between patients with IBD and patients with functional bowel disease. Receiver operating characteristics curve (ROC) was constructed to obtain the optimal cut-off value of FC for distinguishing IBD from functional bowel disease and the corresponding sensitivity and specificity. Results: The median FC levels of patients with IBD in clinical active stage or clinical remission stage was significantly higher than that of patients with functional bowel disease. The median FC levels of patients with IBD in clinical active stage, IBD in clinical remission stage and functional bowel disease were as follow: 699.91 (346.14 ~ 1647.54) μg/g; 407.36 (121.81 ~ 878.48) μg/g; 39.04 (12.09 ~ 81.04) μg/g when FC was measured by FEIA. The median FC levels were 716.99 (240.42 ~ 1232.53) μg/g; 338.46 (53.08 ~ 692.82) μg/g; 41.44 (11.77 ~ 73.19) μg/g among such above three groups of patients respectively, when FC was measured by ELISA kit. The diagnostic value of IBD with FC determined by FEIA (optimal cut-off = 131.79 μg/g) and ELISA kit (optimal cut-off = 121.85 μg/g) presented an area under the curve of 0.881 and 0.873, respectively. Conclusions: FC determined by FEIA was an accurate surrogate marker to distinguish IBD from functional bowel disease.
A nonmonotone adaptive trust-region algorithm for symmetric nonlinear equations  [PDF]
Gong-Lin Yuan, Cui-Ling Chen, Zeng-Xin Wei
Natural Science (NS) , 2010, DOI: 10.4236/ns.2010.24045
Abstract: In this paper, we propose a nonmonotone adap-tive trust-region method for solving symmetric nonlinear equations problems. The convergent result of the presented method will be estab-lished under favorable conditions. Numerical results are reported.
Color-Tunable Hybrid White Organic Light-Emitting Diodes with Double Interlayers  [PDF]
Chunhong Gao, Ziyang Xiong, Fuxing Yu, Xingjuan Ma, Yue Zhang, Xin Zeng, Zuhong Xiong
Optics and Photonics Journal (OPJ) , 2017, DOI: 10.4236/opj.2017.78B014
Abstract:
An efficient color-tunable hybrid white organic light-emitting diode is demonstrated with double interlayers of 2,7-bis(carbazol-9-yl)-9,9-ditoylfluo- rene/2-(diphenylphosphoryl) spiroflu-orene (DMFL-CBP/SPPO1) inserted between blue fluorescent and yellow phosphorescent-emitting layers, and exhibits Commission Internationale de l’Eclairage (CIE1931) ranging from warm white (0.4368, 0.4497) to cool white (0.2781, 0.2896) with driving current density from 0.2 to 40 mA/cm2. The recombination of singlet and the triplet excitons in blue fluores-cent-emitting layer and yellow phosphorescent-emitting layer, respectively, can be modulated by both the thickness of these double interlayers and the applied current densities.
Percutaneous Endoscopic Lumbar Spine Surgery for Lumbar Disc Herniation and Lumbar Spine Stenosis: Emphasizing on Clinical Outcomes of Transforaminal Technique  [PDF]
Singh Ratish, Zeng-Xin Gao, Hirachan Mangal Prasad, Zhang Pei, Dangol Bijendra
Surgical Science (SS) , 2018, DOI: 10.4236/ss.2018.92007
Abstract: Lumbar Disc Herniation and Lumbar Spine Stenosis are the most common spine diseases which are mainly due to age related Spine degeneration. Diagnosis of both Lumbar Disc Herniation and Lumbar Spine Stenosis depends on clinical findings as well as radiological investigations. Treatment of choice of these conditions is on the basis of the patient conditions. Surgical treatment is the option only when the conservative treatment does not improve the patient’s clinical condition. Advancement and improvement of the technology have resulted in the traditional open surgical treatment into minimal invasive surgery. Intervention of the different surgical instruments with expert spinal surgeons had made percutaneous endoscopic lumbar Spine surgery as one of the preferred choices of surgery for treating Lumbar Disc Herniation and Lumbar Spine Stenosis. The concept of percutaneous endoscopic surgery for lumbar region is to provide surgical options without producing iatrogenic morbidity associated with the open surgical procedures. Conventionally, there are different approaches/techniques for Percutaneous Endoscopic Lumbar Spine Surgery, but in this review we are mainly focusing on the Transforaminal Technique. Regarding the Lumbar Disc Herniation treatment with transforaminal approach, a number of articles have been published due to which we mainly focused on those articles which were published after 2009 onwards. While fewer articles related to Lumbar Spine Stenosis treatment with Transforaminal approach were found, we tried to brief out all those articles. On the basis of comparative study of different surgeries done for Lumbar Disc Herniation and Lumbar Spine Stenosis, Percutaneous Transforaminal endoscopic Lumbar Surgery provides a substantial benefit. Transforaminal approach for treating Lumbar Disc Herniation and Lumbar Spine Stenosis is safe and effective. The Percutaneous Transforaminal Endoscopic Lumbar Surgery has advantage as it is performed under local anesthesia with shorter length of hospitalization and early return to normal life. The clinical outcome of the patient that underwent Percutaneous Transforaminal Endoscopic Lumbar Surgery for Lumbar Disc Herniation and Lumbar Spine Stenosis is quite good in regard of its fewer complication and more benefits.
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