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Search Results: 1 - 10 of 25941 matches for " Pu He "
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Research on Classification and Development of College Teachers in the Context of Value Pluralism  [PDF]
Pu He, Hong Zhang, Youbin Zhao
Advances in Anthropology (AA) , 2016, DOI: 10.4236/aa.2016.64013
Abstract: The number of Chinese college teachers is considerably large, and these teachers have their own focus on teaching, research, social services and other different orientations. Given that, the teacher evaluation system operated in a single way has caused widespread problem that the teachers lack developing motivation and attach importance to scientific research rather than teaching. According to the classification of human values and definition of teacher development, this article proposes five development categories of college teachers in the context of plural values. The only way to achieve the development of college teachers is to fully respect their needs of personalized development and provide guidance according to their classification.
Semantic Clustering Based Relevance Language Model
Qiang Pu,Daqing He
Information Technology Journal , 2010,
Abstract: How to effectively generate clusters and use the information in clusters to improve information retrieval performance are still open research questions. By viewing a document as an interaction of a set of independent hidden topics, we propose a novel semantic clustering technique using independent component analysis. Then within language modeling framework, we apply the obtained semantic topic clusters into the estimation process of relevance model. We expect that semantic clustering will filter out those noisy documents so that the estimation of relevance model is only based on relevant documents and some useful semantic information. A semantic cluster is activated to be the most similar to a user’s information need by user’s query, the documents in the activated semantic cluster and the keywords of representing the activated semantic cluster are used for the estimation of relevance model. Therefore, we obtain a semantic cluster based relevance language model that uses pseudo relevance feedback technique without requiring any relevance training information. We applied the model in experiments on five TREC data sets. The experiment results show that our model can significantly improve retrieval performance over previous language models including relevance-based language models. We think that the main contribution of the improved performance comes from the estimation of relevance model on the semantic cluster that is closely related to a user’s information need.
A Full-Duplex PON with Hybrid 64/16/4QAM OFDM Downlink and Hybrid 16/8/QPSK OFDM Uplink  [PDF]
Chao He, Zefu Tan, Yufeng Shao, Li Cai, Yunle Zhu, Hesheng Pu, Sisi Huang
Optics and Photonics Journal (OPJ) , 2016, DOI: 10.4236/opj.2016.68B017
Abstract:
In the context of next-generation optical access networks beyond 10 G, for high SE and flexible dynamic bandwidth allocation (DBA), the scheme of hybrid 64/16/4QAM-OFDM signal for downlink transmission and hybrid 16/8/QPSK-OFDM signal for uplink transmission is successfully proposed and experimentally presented in a full-duplex PON based on OFDM system. Here, for the uplink, in order to unit management of the optical line terminal (OLT) and reduce cost, the optical source functioned as the optical subcarrier at optical network units (ONUs) is from OLT in the central station. Moreover, there is an external cavity laser (ECL) with center frequency of 193.2 THz not only employed as optical modulated signal but also acted as LO signal. Our simulation results show that bit error ratio (BER) under hardware detection forward error correction has been successfully gained after 20 km of SSMF transmission. It is observed that the receiver sensitivity of multilevel PSK (M-PSK) is obviously larger than that of the M-QAM in this measurement scheme.
Productivity and the Survival Rate after Winter Management of Seven Tropical Forage Accessions in Subtropical Region of China  [PDF]
Chengxin He, Ling Mo, Yuqing Huang, Zhongfeng Zhang, Michael Hare, Danjuan Zen, Gaozhong Pu
Agricultural Sciences (AS) , 2017, DOI: 10.4236/as.2017.85034
Abstract: Forage production and quality of five tropical grass accessions (Guimu-1 hybrid elephant grass (PG1), Mulato II (M II), Ubon paspalum (PU), hybrid elephant grass (PH) and Reyan 11 paspalum (PR11)) and two tropical legume accessions (Reyan 5 stylo (SR5) and Ubon stylo (SU)) were evaluated in a field experiment in a subtropical area with hot summers and cold winters in Guangxi, China. Three forage stubble cover managements: no cover (CK), dry mass cover (MC) and plastic cover (PC) were applied at the end of the summer period to evaluate cold tolerance and accession survival over the winter. Photosynthesis measurements were taken from the forages in mid-summer. The results showed that PG1 accession produced significantly higher dry matter yields (67.0 t·ha-1) than the other grass and legume accessions. Legume accessions SU and SR5 produced much less dry matter (6.4 - 7.2 t·ha-1) compared to the grasses. M II, PU and PR11 contained the largest proportion of leaf. PG1 and PH showed good cold tolerance (survival rate >85%) under -1°C conditions without any cover management. PR11 had better cold tolerance than PU. M II
Location Based Recommendation for Mobile Users Using Language Model and Skyline Query
Qiang Pu,Ahmed Lbath,Daqing He
International Journal of Information Technology and Computer Science , 2012,
Abstract: Location based personalized recommendation has been introduced for the purpose of providing a mobile user with interesting information by distinguishing his preference and location. In most cases, mobile user usually does not provide all attributes of his preference or query. In extreme case, especially when mobile user is moving, he even does not provide any preference or query. Meanwhile, the recommendation system database also does not contain all attributes that can express what the user needs. In this paper, we design an effective location based recommendation system to provide the most possible interesting places to a user when he is moving, according to his implicit preference and physical moving location without the user’s providing his preference or query explicitly. We proposed two circle concepts, physical position circle that represents spatial area around the user and virtual preference circle that is a non-spatial area related to user’s interests. Those skyline query places in physical position circle which also match mobile user’s implicit preference in virtual preference circle will be recommended. User’s implicit preference will be estimated under language modeling framework according to user’s historical visiting behaviors. Experiments show that our method is effective in recommending interesting places to mobile users. The main contribution of the paper comes from the combination of using skyline query and information retrieval to do an implicit location-based personalized recommendation without user’s providing explicit preference or query.
Squeezing electromagnetic energy with a dielectric split ring inside a permeability-near-zero metamaterial
Yi Jin,Pu Zhang,Sailing He
Physics , 2009, DOI: 10.1103/PhysRevB.81.085117
Abstract: A novel electromagnetic energy squeezing mechanism is proposed based on the special properties of permeability-near-zero metamaterials. Nearly no energy stream can enter a conventional dielectric region positioned inside a permeability-near-zero material. When a source is surrounded by a dielectric split ring (encloser with a gap opened), the electromagnetic energy generated by the source is forced to propagate through the gap. When the gap is narrow, the energy stream density becomes very large and makes the magnetic field enhanced drastically in the gap. The narrow gap can be long and bended. This provides us a method to obtain strong magnetic field without using resonance enhancement.
Carpet cloaking on a dielectric half-space
Pu Zhang,Micha?l Lobet,Sailing He
Physics , 2010, DOI: 10.1364/OE.18.018158
Abstract: Carpet cloaking is proposed to hide an object on a dielectric half-space from electromagnetic (EM) detection. A two-dimensional conformal transformation specified by an analytic function is utilized for the design. Only one nonsingular material parameter distribution suffices for the characterization. The cloaking cover situates on the dielectric half-space, and consists of a lossless upper part for EM wave redirection and an absorbing bottom layer for inducing correct reflection coefficient and absorbing transmission. Numerical simulations with Gaussian beam incidence are performed for verification.
Inverse Transformation Optics and Reflection Analysis for Two-Dimensional Finite Embedded Coordinate Transformation
Pu Zhang,Yi Jin,Sailing He
Physics , 2009, DOI: 10.1109/JSTQE.2009.2031163
Abstract: Inverse transformation optics is introduced, and used to calculate the reflection at the boundary of a transformation medium under consideration. The transformation medium for a practical device is obtained from a two-dimensional (2D) finite embedded coordinate transformation (FECT) which is discontinuous at the boundary. For an electromagnetic excitation of particular polarization, many pairs of original medium (in a virtual space V') and inverse transformation can give exactly the same anisotropic medium through the conventional procedure of transformation optics. Non-uniqueness of these pairs is then exploited for the analysis and calculation of the boundary reflection. The reflection at the boundary of the anisotropic FECT medium (associated with the corresponding vacuum virtual space V) is converted to the simple reflection between two isotropic media in virtual space V' by a selected inverse transformation continuous at the boundary. A reflectionless condition for the boundary of the FECT medium is found as a special case. The theory is verified numerically with the finite element method.
Abnormal enhancement of electric field inside a thin permittivity-near-zero object in free space
Yi Jin,Pu Zhang,Sailing He
Physics , 2010, DOI: 10.1103/PhysRevB.82.075118
Abstract: It is found that the electric field can be enhanced strongly inside a permittivity-near-zero object in free space, when the transverse cross section of the object is small and the length along the propagation direction of the incident wave is large enough as compared with the wavelength. The physical mechanism is explained in details. The incident electromagnetic energy can only flow almost normally through the outer surface into or out of the permittivity-near-zero object, which leads to large energy stream density and then strong electric field inside the object. Meanwhile, the magnetic field inside the permittivity-near-zero object may be smaller than that of the incident wave, which is also helpful for enhancing the electric field. Two permittivity-near-zero objects of simple shapes, namely, a thin cylindrical shell and a long thin rectangular bar, are chosen for numerical illustration. The enhancement of the electric field becomes stronger when the permittivity-near-zero object becomes thinner. The physical mechanism of the field enhancement is completely different from the plasmonic resonance enhancement at a metal surface.
A novel dual-band balun based on the dual structure of composite right/left handed transmission line
Hu Xin,Zhang Pu,He Sailing
Physics , 2006,
Abstract: Utilizing the opposite phase shifting property of a standard Composite Right/Left Handed (CRLH) transmission line (TL) and a dual structure of CRLH (D-CRLH) TL, a dual-band balun is designed. The dual-band balun is formed by a 1x2 (3-dB) splitter with a D-CRLH phase-shifting line in the top branch and a CRLH phase-shifting line in the bottom branch. The performance of the balun is verified with circuit simulation at 2.4 GHz and 5.0GHz. The balun exhibits a very wide bandwidth for differential output phase, the return loss is well below -100dB, and the insertion losses |S12| and |S13| are around -3.03dB at both frequencies.
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