Showing papers by "Renmin University of China published in 2007"

The urban–rural income gap and inequality in china

Abstract: Using new household survey data for 1995 and 2002, we investigate the size of China's urban–rural income gap, the gap's contribution to overall inequality in China, and the factors underlying the gap. Our analysis improves on past estimates by using a fuller measure of income, adjusting for spatial price differences and including migrants. Our methods include inequality decomposition by population subgroup and the Oaxaca–Blinder decomposition. Several key findings emerge. First, the adjustments substantially reduce China's urban–rural income gap and its contribution to inequality. Nevertheless, the gap remains large and has increased somewhat over time. Second, after controlling for household characteristics, location of residence remains the most important factor underlying the urban–rural income gap. The only household characteristic that contributes substantially to the gap is education. Differences in the endowments of, and returns to, other household characteristics such as family size and composition, landholdings, and Communist Party membership are relatively unimportant.

Identification of overlapping community structure in complex networks using fuzzy c-means clustering

Abstract: Identification of (overlapping) communities/clusters in a complex network is a general problem in data mining of network data sets. In this paper, we devise a novel algorithm to identify overlapping communities in complex networks by the combination of a new modularity function based on generalizing NG's Q function, an approximation mapping of network nodes into Euclidean space and fuzzy c-means clustering. Experimental results indicate that the new algorithm is efficient at detecting both good clusterings and the appropriate number of clusters.

Faster than Hermitian quantum mechanics.

Abstract: Given an initial quantum state $|{\ensuremath{\psi}}_{I}⟩$ and a final quantum state $|{\ensuremath{\psi}}_{F}⟩$, there exist Hamiltonians $H$ under which $|{\ensuremath{\psi}}_{I}⟩$ evolves into $|{\ensuremath{\psi}}_{F}⟩$. Consider the following quantum brachistochrone problem: subject to the constraint that the difference between the largest and smallest eigenvalues of $H$ is held fixed, which $H$ achieves this transformation in the least time $\ensuremath{\tau}$? For Hermitian Hamiltonians $\ensuremath{\tau}$ has a nonzero lower bound. However, among non-Hermitian $\mathcal{P}\mathcal{T}$-symmetric Hamiltonians satisfying the same energy constraint, $\ensuremath{\tau}$ can be made arbitrarily small without violating the time-energy uncertainty principle. This is because for such Hamiltonians the path from $|{\ensuremath{\psi}}_{I}⟩$ to $|{\ensuremath{\psi}}_{F}⟩$ can be made short. The mechanism described here is similar to that in general relativity in which the distance between two space-time points can be made small if they are connected by a wormhole. This result may have applications in quantum computing.

Finding Top-k Min-Cost Connected Trees in Databases

Abstract: It is widely realized that the integration of database and information retrieval techniques will provide users with a wide range of high quality services. In this paper, we study processing an l-keyword query, p1, p1, ..., pl, against a relational database which can be modeled as a weighted graph, G(V, E). Here V is a set of nodes (tuples) and E is a set of edges representing foreign key references between tuples. Let Vi ⊆ V be a set of nodes that contain the keyword pi. We study finding top-k minimum cost connected trees that contain at least one node in every subset Vi, and denote our problem as GST-k When k = 1, it is known as a minimum cost group Steiner tree problem which is NP-complete. We observe that the number of keywords, l, is small, and propose a novel parameterized solution, with l as a parameter, to find the optimal GST-1, in time complexity O(3ln + 2l ((l + logn)n + m)), where n and m are the numbers of nodes and edges in graph G. Our solution can handle graphs with a large number of nodes. Our GST-1 solution can be easily extended to support GST-k, which outperforms the existing GST-k solutions over both weighted undirected/directed graphs. We conducted extensive experimental studies, and report our finding.

China's Local and National Fertility Policies at the End of the Twentieth Century

Abstract: In this article we survey variations in Chinas fertility policy as of the late 1990s in an attempt to describe local policy and the implications of the aggregation of local policies for national policy. Following a brief discussion of the politics of population policymaking in contemporary China we summarize fertility policy regulations within Chinas provinces. Our survey illustrates the intricacies and complexities of the population control process in China and serves as a background for our detailed analysis of the policy-stipulated fertility level in China based on local fertility policies. Using data collected on fertility policy for 420 prefecture-level units in China the administrative level below the province we estimate fertility levels that would obtain locally if all married couples had births at the levels permitted by local policy. Chinese birth control officials term this fertility level as "policy fertility" (zhengce shengyulu). We compute the average provincial and national policy fertility levels implied by policy fertility at the prefecture level and map the geographic and demographic distributions of policy fertility in China. This policy fertility level is a quantitative summary of Chinas current fertility policy informing what is pursued in terms of population control nationally on the basis of diverse local policies. Policy fertility serves as a reference for evaluating Chinas fertility policy implementation and as a starting point in evaluating the necessity and feasibility of continuing Chinas current fertility policy. (excerpt)

Integrity auditing of outsourced data

Abstract: An increasing number of enterprises outsource their IT services to third parties who can offer these services for a much lower cost due to economy of scale. Quality of service is a major concern in outsourcing. In particular, query integrity, which means that query results returned by the service provider are both correct and complete, must be assured. Previous work requires clients to manage data locally to audit the results sent back by the server, or database engine to be modified for generating authenticated results. In this paper, we introduce a novel integrity audit mechanism that eliminating these costly requirements. In our approach, we insert a small amount of records into an outsourced database so that the integrity of the system can be effectively audited by analyzing the inserted records in the query results. We study both randomized and deterministic approaches for generating the inserted records, as how these records are generated has significant implications for storage and performance. Furthermore, we show that our method is provable secure, which means it can withstand any attacks by an adversary whose computation power is bounded. Our analytical and empirical results demonstrate the effectiveness of our method.

Controlled Synthesis of the ZnWO4 Nanostructure and Effects on the Photocatalytic Performance

Abstract: ZnWO4 photocatalysts with various morphologies were synthesized by a hydrothermal process. The effects of hydrothermal temperature and time on the crystallinity and morphology of ZnWO4 catalyst were investigated. The crystallinity was enhanced with the increase of hydrothermal temperature and hydrothermal time. The formation of ZnWO4 nanoparticles was controlled via kinetic process above 160 °C, and ZnWO4 nanorods with a highly [100]-preferred orientation formed via the thermodynamically control process in the temperature range of 120−140 °C. The morphology and crystallinity of ZnWO4 photocatalyst have a significant influence on the photocatalytic activity for aqueous Rhodamine B and gaseous formaldehyde degradation. ZnWO4 nanorod catalyst showed a much higher photocatalytic activity than the nanoparticle one. The enhanced photocatalytic activity can be attributed to the anisotropic structure of nanorod.

The independence of fuzzy variables with applications to fuzzy random optimization

Abstract: This paper presents the independence of fuzzy variables as well as its applications in fuzzy random optimization. First, the independence of fuzzy variables is defined based on the concept of marginal possibility distribution function, and a discussion about the relationship between the independent fuzzy variables and the noninteractive (unrelated) fuzzy variables is included. Second, we discuss some properties of the independent fuzzy variables, and establish the necessary and sufficient conditions for the independent fuzzy variables. Third, we propose the independence of fuzzy events, and deal with its fundamental properties. Finally, we apply the properties of the independent fuzzy variables to a class of fuzzy random programming problems to study their convexity.

Phase diagram of a strongly interacting polarized fermi gas in one dimension

Abstract: Based on the integrable Gaudin model and local density approximation, we discuss the ground state of a one-dimensional trapped Fermi gas with imbalanced spin population, for an arbitrary attractive interaction. A phase separation state, with a polarized superfluid core immersed in an unpolarized superfluid shell, emerges below a critical spin polarization. Above it, coexistence of polarized superfluid matter and a fully polarized normal gas is favored. These two exotic states could be realized experimentally in highly elongated atomic traps, and diagnosed by measuring the lowest density compressional mode. We identify the polarized superfluid as having an Fulde-Ferrell-Larkin-Ovchinnikov structure, and predict the resulting mode frequency as a function of the spin polarization.

Evaluating Continuous Training Programs Using the Generalized Propensity Score

Abstract: This paper assesses the dynamics of treatment effects arising from variation in the duration of training. We use German administrative data that have the extraordinary feature that the amount of treatment varies continuously from 10 days to 395 days (i.e. 13 months). This feature allows us to estimate a continuous dose-response function that relates each value of the dose, i.e. days of training, to the individual post-treatment employment probability (the response). The dose-response function is estimated after adjusting for covariate imbalance using the generalized propensity score, a recently developed method for covariate adjustment under continuous treatment regimes. Our data have the advantage that we can consider both the actual and planned training durations as treatment variables: If only actual durations are observed, treatment effect estimates may be biased because of endogenous exits. Our results indicate an increasing dose-response function for treatments of up to 100 days, which then flattens out. That is, longer training programs do not seem to add an additional treatment effect.

Adolescents' paternal attachment and Internet use.

Abstract: As children approach middle childhood and adolescence, the influence of fathers on children's behavior and development becomes more equivalent to that of mothers. The quality of father-child attachment operates as a stronger predictor of adolescents' cognitive and emotional development. During adolescence, symbolic communication by means of the Internet becomes increasingly more important than physical approximate-seeking behavior in infancy and childhood. Adolescents might regard the Internet as their new attachment figure or may seek new attachment figures through the Internet. This study was designed to address the impacts of father-adolescent attachment on adolescents' Internet use. Seven hundred twelve adolescent participants completed questionnaires to assess the associations among their paternal attachment, intensity of Internet use, and Internet services preference. The result revealed that alienation positively predicted pathological Internet use (PIU) directly and also indirectly mediated by leisure services preference. Trust predicted PIU negatively. These results help to provide parents and educators with guidance in adolescents' more appropriate Internet use.

Uncovering fuzzy community structure in complex networks.

Abstract: There has been an increasing interest in properties of complex networks, such as small-world property, power-law degree distribution, and network transitivity which seem to be common to many real world networks. In this study, a useful community detection method based on non-negative matrix factorization (NMF) technique is presented. Based on a popular modular function, a proper feature matrix from diffusion kernel and NMF algorithm, the presented method can detect an appropriate number of fuzzy communities in which a node may belong to more than one community. The distinguished characteristic of the method is its capability of quantifying how much a node belongs to a community. The quantification provides an absolute membership degree for each node to each community which can be employed to uncover fuzzy community structure. The computational results of the method on artificial and real networks confirm its ability.

Universal thermodynamics of strongly interacting Fermi gases

Abstract: Strongly interacting Fermi gases are of great current interest. Not only are fermions the most common particles in the universe, but they are also thought to have a universal thermodynamic behaviour for strong interactions1, 2, 3. Recent experiments on ultracold Fermi gases provide an unprecedented opportunity to test universality in the laboratory4, 5, 6, 7, 8. In principle this allows—for example—the interior properties of hot, dense neutron stars to be investigated on earth. Here we carry out a detailed test of this prediction. We analyse results from three ultracold fermion experiments involving two completely distinct atomic species in different kinds of atomic-trap environment6, 7, 8. The data are compared with the predictions of a recent strong-interaction theory9, 10. Excellent agreement is obtained, with no adjustable parameters. By extrapolating to zero temperature, we show that the experimental measurements yield a many-body parameter -0.590.07, describing the universal energy of strongly interacting Fermi gases.

Recommendation model based on opinion diffusion

Abstract: Information overload in the modern society calls for highly efficient recommendation algorithms. In this letter we present a novel diffusion based recommendation model, with users' ratings built into a transition matrix. To speed up computation we introduce a Green function method. The numerical tests on a benchmark database show that our prediction is superior to the standard recommendation methods.

Recommendation model based on opinion diffusion

Abstract: Information overload in the modern society calls for highly efficient recommendation algorithms. In this letter we present a novel diffusion-based recommendation model, with users' ratings built into a transition matrix. To speed up computation we introduce a Green function method. The numerical tests on a benchmark database show that our prediction is superior to the standard recommendation methods.

Feeling trusted by business leaders in China: Antecedents and the mediating role of value congruence

Abstract: This paper examines the antecedents of felt trust, an under-explored area in the trust literature. We hypothesized that subordinates’ felt trust would relate positively with their leaders’ moral leadership behaviors and negatively with autocratic leadership behaviors and demographic differences between leaders and themselves. We also hypothesized the above relationships to be mediated by the leader-member value congruence. Results supported our hypotheses that value congruence mediated between autocratic leadership behaviors and demographic differences and subordinates’ felt trust, but not moral leadership behaviors, which had direct effects on subordinates’ perception of feeling trusted. Theoretical and practical implications are discussed.

A sharp form of the Moser-Trudinger inequality on a compact Riemannian surface

Abstract: In this paper, a sharp form of the Moser-Trudinger inequality is established on a compact Riemannian surface via the method of blow-up analysis, and the existence of an extremal function for such an inequality is proved

Sexual Practices and Sexual Satisfaction: A Population Based Study of Chinese Urban Adults

Abstract: This study examined sexual satisfaction and its social and behavioral correlates among urbanites aged 20–64 in China, using data from a nationally representative sample of 1,194 women and 1,217 men with a spouse or other long-term sexual partner with whom they had sex during the last year. The results from structural equation models suggest a multiplex set of determinants of sexual satisfaction, including relationship characteristics, sexual knowledge and personal values, physical vitality, and environmental impediments. A large proportion of the effect of these background characteristics was mediated by frequent orgasms, varied sexual practices, and perceived partner affection. In particular, much of the effect of knowledge and beliefs was mediated through variety in sexual practices. While many of the observed patterns were shared among women and men, much of the effect of relationship characteristics was mediated through perceived partner affection for women. Men, in contrast, paid greater attention to his partner's physical attractiveness and to her extramarital sex. A sexual transition is well underway in urban China, even if more rapidly for men than for women. While knowledge and values are arguably more important in this transitional period, many antecedents of sexual well-being drawn from the literature on sexual behavior in developed Western countries are also applicable to urban China.

Novel quantum phases of dipolar bose gases in optical lattices

Abstract: We investigate the quantum phases of polarized dipolar bosons loaded into a two-dimensional square and three-dimensional cubic optical lattices. We show that the long-range and anisotropic nature of the dipole-dipole interaction induces a rich variety of quantum phases, including the supersolid and striped supersolid phases in two-dimensional lattices, and the layered supersolid phase in three-dimensional lattices.

Puerarin and conjugate bases as radical scavengers and antioxidants: molecular mechanism and synergism with beta-carotene.

Abstract: The 4'-hydroxyl group of puerarin, a C-glycoside of the isoflavonoid daidzein, was shown, using 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical cation and stopped-flow spectroscopy and by comparison with the 7-propylpuerarin (A ring derivative) and 4'-propylpuerarin (B ring derivative), to be a more efficient radical scavenger as compared to the 7-hydroxyl group by a factor of 2, a difference increasing upon deprotonation. The difference in radical scavenging agreed with the oxidation potentials (cyclic voltammetry in acetonitrile, 0.1 M Bu4NBF4 at 25 degrees C): E/mV=862+/-3 for puerarin, 905+/-10 for 7-propylpuerarin, and 1064+/-2 for 4'-propylpuerarin relative to ferrocene/ferricenium. In aqueous solution, the reduction potential was shown to decrease for increasing pH, and deprotonation of the 4'-hydroxyl group increased radical scavenging more than deprotonation of the 7-hydroxyl group. The 7-hydroxyl was found to be more acidic (pKa1=7.20+/-0.01 in puerarin and pKa=7.23+/-0.01 in 4'-propylpuerarin) than the 4'-hydroxyl group (pKa2=9.84+/-0.08 in puerarin and pKa=9.51+/-0.02 in 7-propylpuerarin); aqueous solution, ionic strength of 0.1, and 25 degrees C. In phosphatidyl choline liposome of pH 7.4, puerarin and beta-carotene each showed a modest antioxidant activity measured as prolongation of the lag phase for formation of conjugate dienes and using the water-soluble radical initiator APPH with effects of puerarin and beta-carotene being additive. For the lipophilic initiator AMVN, the antioxidative effect decreased for puerarin and increased for beta-carotene as compared to APPH and showed a clear synergism. A regeneration of beta-carotene, effective in the liposome lipid phase as antioxidant, from the cation radical by deprotonated forms of puerarin was demonstrated in 9:1 chloroform/methanol using laser flash photolysis with k2=2.7x10(4) L mol-1 s-1 for the bimolecular process between the cation radical and the puerarin dianion.

Origin of Photocatalytic Deactivation of TiO2 Film Coated on Ceramic Substrate

Abstract: The deactivation origin of the TiO2 film coated on an Al2O3-based ceramic substrate was revealed via investigating the physicochemical behaviors of the mixtures of TiO2 with different oxides of various species found in the film such as Al, Si, and Ca. The production of these species mainly present as individual oxides at the boundaries among the TiO2 particles in the film originated from their thermal diffusion from substrate during the formation of TiO2 film at calcination temperature. It was demonstrated that Al present as Al2O3 with TiO2 caused a remarkable reduction in the production of hydroxyl radicals over the UV-irradiated TiO2, whereas the presence of SiO2 or CaO, especially SiO2, together with TiO2 gave a rise in the formation of hydroxyl radicals. The investigation also showed that a part of Al3+ substitutes for Ti4+ in the TiO2, resulting in the formation of oxygen vacancies in the lattice for the charge balance. The oxygen vacancies present in the TiO2 lattice acting as effective combination ...

Sino-African Relations and the Problem of Human Rights

Abstract: China’s political and economic activities in Africa are increasing at an exponential rate Equally, they are attracting criticism, chiefly over Beijing’s no-strings-attached stance on human rights and governance It is clear that many African states that enjoy Chinese support not only trample on civil and political rights (as per Western ideas of human rights), but also subvert their citizens’ economic and social rights (as per China’s discourse on human rights) If while adhering to the principle of non-interference, Chinese activities actually make things worse for some in Africa, then Beijing’s argument that basic socio-economic rights are more important for the poor than abstract political rights is potentially problematic This is because there is a danger that Beijing’s engagement in Africa might be exploited by autocrats on the continent for their own, well-understood, reasons Doing no harm, rather than a studied disinterest, needs to be part of China’s overall African policy, something that Beijing is bound to recognize The preceding issues are the concern of this chapter

A europium complex with excellent two-photon-sensitized luminescence properties

Abstract: We report the synthesis and excellent two-photon-sensitized luminescence properties of a new complex [Eu(tta) 3 dmbpt] (tta = henoyltrifluoroacetonate; dmbpt=2-(N,N-diethyl-2,6-dimethylanilin-4-yl)-4,6-bis(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine) that exhibits the highest efficiency of lanthanide luminescence when excited by near-infrared (NIR) laser pulses (action cross section of two-photon-excited fluorescence δ x Φ F : 85 GM at 812 nm and 56 GM at 842 nm; 1 GM =10 -50 cm 4 s photon -1 molecule ). Compared to a previously reported [Eu(tta) 3 dpbt] complex, (dpbt = 2-(N,N-diethylanilin-4-yl)-4,6-bis(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine), [Eu(tta) 3 dmbpt] has two excess methyl groups at the 2,6-positions of the phenyl ring. Crystallographic data of dmbpt show that the 2,6-dimethyl substitutes bring about a significant twist in the conformation of the diethylamino group compared to that in dpbt, which severely influences the conjugation in the ground state between the electron lone pair of N in the -N(CH 2 -) 2 moiety and the aromatic electron system in dmbpt. The large two-photon absorption (TPA) cross section of dmbpt is mainly derived from its large static dipole moment difference between the So and the S 1 states, which is partly responsible for the high capability of two-photon-sensitized luminescence of [Eu(tta) 3 dmbpt]. The broader two- and single-photon excitation windows and the superior two-photon-sensitized luminescent properties in the long-wavelength NIR region of [Eu(tta) 3 dmbpt] compared to [Eu(tta) 3 dpbt] are also explained according to the calculated results and twisted structure.

The value of IT to firms in a developing country in the catch-up process: An empirical comparison of China and the United States

Abstract: This study seeks to better understand the role of information technology (IT) to firms in a developing country in the catch-up process. Using the event study methodology, we empirically compare the value of IT investments to firms in China and those in the United States. Three factors that may affect the value of IT (industry, firm size, and firm type) are considered. We find that IT investment announcements significantly increase firms' market value in China but not in the US. This may be evidence that IT brings more benefits to firms in China, helping them to catch up with leader firms in the US. Furthermore, we find that the positive effects of IT investments are more easily observed in IT-using firms than in IT-producing firms in China. Our findings offer further insight into the catch-up theory and the value of IT investments.