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25 November 2016, Volume 2016 Issue 6 Previous Issue    Next Issue

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Degree of enclosure as outdoor space form parameter study based on the urban microclimate analysis: A case study on office building site design in Shanghai ZHANG Shun-yao, CHEN Yi 2016, 2016 (6):  1-26.  doi: 10.3969/j.issn.1000-5641.2016.06.001 Abstract ( 783 )   HTML ( 23 )   PDF (5533KB) ( 1219 )   Save This paper studies the outdoor space form parameter, the correlation between degree of enclosure and urban microclimate, from the perspective of architecture site design. Outdoor space form is one of the control factors that can be used in the built environment adjustment by architects. Urban microclimate is the media and one of the main targets of the built environment regulation. Low carbon emission and energy saving is the goal of environmental regulation. Taking the typical office buildings site in the national anthem square in Shanghai as a case study, field microclimate measuring approach was employed to analyze the correlation between outdoor space form and temperature, wind and sunlight of site microclimate. By analysis of site plan and section, the paper discusses the correlation between outdoor space form and microclimate. The result of the analysis indicates that the temperature, wind speed and solar radiation were significantly influenced by outdoor space geometry. A simple scatter plot and linear fit analysis indicates that the site microclimate is significantly correlated with the “degree of enclosure” contributed by buildings terrain and trees, quantified by the aspect ratio (H/W), plan transparent rate (L/C), Sky view factor (SV F) and Elevation difference (H). It suggests that, within the practical range, increasing SVF could increase air temperature (TMP) and solar radiation (SRD); increasing plan transparent rate (L/C) and aspect ratio (H/W) could decrease wind speed (WNS). Under the measured site environment, SVF cooperated with L/C and aspect ratio (H/W) could indicate the thermal buoyancy driven airflow rate that is determined by solar radiation heating. Summer and winter mathematical model was summarized through multiple regression analysis of outdoor space degree of enclosure parameter and microclimate element. A discussion on thermal environment of the measured site suggests an outdoor space form design approach that goes for diverse space form which combine semi enclosure and semi coverage instead of full enclosure could be the most efficient way to regulate the site microclimate. References | Related Articles | Metrics

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PM2.5 deposition velocity and impact factors on leaves of typical tree species in Shanghai 2016, 2016 (6):  27-37.  doi: 10.3969/j.issn.1000-5641.2016.06.002 Abstract ( 682 )   HTML ( 188 )   PDF (1684KB) ( 963 )   Save The use of urban vegetation has become one of the most important measures to reduce fine particles pollution (PM2.5) in the atmosphere. In this study, PM2.5 dry deposition velocities of 15 common-planted greening trees in Shanghai were firstly measured through strongly blowing method. Wax content, surface roughness and surface free energy of each plant leaves were determined, and the regression model was built to explore the relationship between leaves’ characters and their abilities to detain particles. The results has shown that leaves of Magnolia grandiflora, Podocarpus macrophyllus, Sabina chinensis and some other tree species have a higher PM2.5 dry deposition velocity, which has strong capability of detaining dust; wax content, polar component, dispersion component and arithmetical mean deviation of the profile (Ra) are significant to evergreen trees while insignificant to conifers, and polar component is significant to deciduous trees. Therefore, to improve the particles purification of plants, it is highly recommended that coniferous tree species, broad-leaved trees, such as Prunus cerasifera, Magnolia grandiflora and Sophora japonica and some other trees of high dust retention abilities, should be better options in practice. References | Related Articles | Metrics

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Seasonal dynamics of soil enzyme activities and its correlation with soil physical and chemical properties in five plant communities in Shanghai green land ZHU Sha, WANG Juan-juan, JIN Shi-ke, GAO Qiang, ZHANG Qi, YOU Wen-hui 2016, 2016 (6):  38-45.  doi: 10.3969/j.issn.1000-5641.2016.06.003 Abstract ( 639 )   HTML ( 16 )   PDF (781KB) ( 663 )   Save To explore and compare the correlation between the seasonal dynamics of soil physical and chemical properties and soil enzyme activities (sucarse, urease, phosphatase) in Shanghai green land, soil samples under five types different plant communities which consist of Platanu sacerifolia, Cinnamomum camphora and Metasequoia glyptostroboides were collected and analyzed. Results showed that: First, soil physical and chemical indicators and soil enzyme activities were much higher in broad-leaf forests and mixed forests than those in coniferous and single-dominant forests, respectively. In addition, soil physical and chemical indicators and soil enzyme activities were relative higher in both autumn and winter, and expect urease and phosphatase activities were higher in spring.  Moreover, there were significant interactive effect of plant communities and seasons on soil enzyme activities, but not on soil physical and chemical indicators. On the whole, there were various degrees of correlations between different soil enzymes as well as between soil enzyme activities and soil physical and chemical properties. These results indicated that mixed forests should be the main plant community types in the construction of urban green land, and also the aimed management of soil nutrition status at different periods during the process of urban green land maintenance also should be taken much into account in the future. References | Related Articles | Metrics

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Influence of patch structure on bird community and structure in Shanghai large urban parks YANG Gang, WANG Yong, XU Jie, DING You-zhong, YE Xin, WANG Zheng-huan 2016, 2016 (6):  46-53.  doi: 10.3969/j.issn.1000-5641.2016.06.004 Abstract ( 616 )   HTML ( 22 )   PDF (686KB) ( 883 )   Save The bird community was surveyed in Shanghai Botanical Garden, Century Park, Gongqing Forest Park, Binjiang Forest Park and Haiwan Forest Park during May 2012 to April 2013 by line transect method. We used ArcGIS 10.0 to classify the patches within the urban parks by visual interpretation. Based on the classification, 34 patch variables including patch number, patch density, patch area and patch total edge was set to analyze the relationship between bird communities and patch variables. We used Chi-square test to analyze whether the bird species and abundance in various urban parks differed significantly. Multiple statistical analyses were required to measure how the patch variables affected the bird community composition. Results indicated that there was significant difference among bird richness, bird abundance, the number of patches in 5 urban parks. Multiple linear regression models confirmed that there was significant positive correlation between bird species and the number of Number of Water patches (WNP) and Grassland patches shape index (GSI ). There was significant negative correlation between bird species and the largest patch index (LPI ). Bird abundance was significant positive correlation with size of Plant patches (PPS), mean size of patches (MPS) and was significant negative correlation with total edge of Plant patches (PTE). In addition, suggestions in relation to the construction of urban parks and vegetation configuration were put forward according to the above results. References | Related Articles | Metrics

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Phytoplankton functional cohort study of Shanghai Dianshan Lake in spring and summer ZHANG Qi, JIANG Yue, JIN Shi-ke, WANG Juan-juan, ZHU Sha, BO Fang-fang, YOU Wen-hui 2016, 2016 (6):  54-64.  doi: 10.3969/j.issn.1000-5641.2016.06.005 Abstract ( 540 )   HTML ( 7 )   PDF (745KB) ( 729 )   Save From the perspective of ecology and by using the theory of ecological niche, phytoplankton functional group has a better description about the relationship between phytoplankton and their environment, and provides a more accurate basis for freshwater system research about the composition of phytoplankton and water monitoring. This research of phytoplankton functional group composition and influence factor is carried out in spring and summer in 2015 in Shanghai Dianshan Lake, and phytoplankton were collected and respectively in the function of the corresponding group. The results for spring function group (20 in total) B, C, D, E, F, G, H1, J, Lo, M, MP, P, TB, TC, W1, W2, X1, X2, X3, and Z. Summer function group (17 in total) includes B, C, D, F, G, J, Lo, M, MP, TB, TC, W1, W2, X1, X2, X3, and Z. Advantage function group for the spring is X1, X2 and, Lo, J; summer advantage function group is X2, X1, P, Lo. Through the analysis of the RDA, the main factor which has a great influence on phytoplankton advantages is Kd, T, DO,  and TP. References | Related Articles | Metrics

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The decycling number and vertex coloring of Halin graphs WANG Yong-qiang, REN Han 2016, 2016 (6):  65-70.  doi: 10.3969/j.issn.1000-5641.2016.06.006 Abstract ( 630 )   HTML ( 12 )   PDF (331KB) ( 947 )   Save According to the structural theorem of 3-connected graphs by Tutte, every 3-connected graph can be obtained by splitting vertices of some wheel which is Halin graph, which indicates that the study of the structure of Halin graph is important in graph structures. In this paper, firstly we dealt with the decycling number of the nearly k-regular Halin graphs, and we got the bidirectional inequality that the decycling numbers of nearly regular Halin graphs must satisfy, then we proved that the boundaries above are tight and got the boundaries of Halin graphs with the most biggest degree or the least degree k. At last, we gave a new proof to the theorem about the (vertex) coloring of Halin graphs. References | Related Articles | Metrics

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Global existence and decay estimate of the solution for a BBM-Burgers equation without viscosity XU Hong-mei, XU Wei 2016, 2016 (6):  71-76.  doi: 10.3969/j.issn.1000-5641.2016.06.007 Abstract ( 481 )   HTML ( 10 )   PDF (242KB) ( 773 )   Save By constructing a Cauchy approximating sequence, we prove the local existence and give the decay estimate of the solution for a BBM-Burgers equation without viscosity. Using the variation of constant formula and the decay estimate of the fundamental solution, we obtain the global existence and decay estimate of solution of the system with small initial data. References | Related Articles | Metrics

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Lp solutions of BSDEs with weakly monotonic and uniformly continuous generators LIAO Jun-xia, FAN Sheng-jun 2016, 2016 (6):  77-87.  doi: 10.3969/j.issn.1000-5641.2016.06.008 Abstract ( 523 )   HTML ( 11 )   PDF (231KB) ( 834 )   Save This paper is devoted to solving one-dimensional backward stochastic differential equations (BSDEs) whose generator g satisfies a (p ^ 2)-order weak monotonicity condition together with a general growth condition in y and a uniform continuity condition in z. Using the convolution technique and Girsanov’s theorem, we establish an existence and uniqueness result for Lp (p > 1) solutions of this kind of BSDEs, which generalizes some existing results. References | Related Articles | Metrics

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Inverse completion for partial matrices ZHAO Lin-lin, ZHANG Li-hua, YAN Li-mei 2016, 2016 (6):  88-93.  doi: 10.3969/j.issn.1000-5641.2016.06.009 Abstract ( 354 )   HTML ( 7 )   PDF (209KB) ( 701 )   Save Two kinds of inverse completion problems for partial matrices were studied by using the rank theory and the Moore-Penrose generalized inverse. Necessary and sufficient conditions for these problems to have a solution were determined and their complete solutions were presented. References | Related Articles | Metrics

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On the asymptotic behavior of solutions of nonlinear ordinary differential equations SERGEY Prokhozhiy, NI Ming-kang 2016, 2016 (6):  94-101.  doi: 10.3969/j.issn.1000-5641.2016.06.010 Abstract ( 518 )   HTML ( 15 )   PDF (195KB) ( 782 )   Save In this paper we investigate the asymptotic behavior of solutions of the Cauchy problem for nonlinear ordinary differential equation v''-c1(vn)'-c2vp=0. All interrelations of parameters are considered. The first asymptotic term and in a number of cases the second asymptotic term is found. The Cauchy problem is investigated both for positive and negative values of argument. References | Related Articles | Metrics

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The Euler characteristic of orbit configuration space of moment-angle complex MENG Yuan-yuan, WANG Yan-ying 2016, 2016 (6):  102-110.  doi: 10.3969/j.issn.1000-5641.2016.06.011 Abstract ( 418 )   HTML ( 7 )   PDF (331KB) ( 656 )   Save Let Im be the m-dimensional standard cube and K′ the barycentric subdivision of simplicial complex K. There is a PL (piecewise linear) embedding of the cone over K′ to the canonical simplicial subdivision of Im by some rules. Then we obtain a kind of cubical complex cc(K) associated to K. According to the construction of cc(K), we calculate the f-vector of cc(K), i.e., the number of cells in every dimension. There is a definition of moment-angle complex Z K,d over cc(K) by the pullback of the projection (Dd)m→Im. Putting Z K,d into the framework of orbit configuration spaces, we get the orbit configuration space FG(Z K,d,n). By using the famous Inclusion-exclusion Principle and the combinatorial structure of FG(Z K,d,n), we obtain the formula for the Euler characteristic of orbit configuration space FG(Z K,d,n) in terms of f-vector. In addition, we provided a new method of calculating the Euler characteristic of moment-angle complex Z K,d. References | Related Articles | Metrics

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The relationship between SVEP and Weyl type theorem under small perturbations DONG Jiong, CAO Xiao-hong, LIU Jun-hui 2016, 2016 (6):  111-118.  doi: 10.3969/j.issn.1000-5641.2016.06.012 Abstract ( 445 )   HTML ( 9 )   PDF (291KB) ( 728 )   Save Let H be an infinite dimensional separable complex Hilbert space and B(H) be the algebra of all bounded linear operators on H. T ∈ B(H) satisfies Weyl’s theorem if σ(T)\σω(T)=π00(T),  where σ(T) and σω(T) denote the spectrum and the Weyl spectrum of T respectively, π00(T)={λ ∈ isoσ(T): 0<dim N(T-λI)<∞}. If σ(T)\σω(T)   π00(T),  T is called satisfying Browder’s theorem. In this paper, using the property of generalized Kato decomposition, we explore the relation between the single-valued extension property and Weyl’s theorem under small compact perturbations. References | Related Articles | Metrics

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Maximal space-like submanifolds in locally symmetric pseudo-Riemannian manifolds LIU Jian-cheng, WANG Feng 2016, 2016 (6):  119-126.  doi: 10.3969/j.issn.1000-5641.2016.06.013 Abstract ( 471 )   HTML ( 11 )   PDF (280KB) ( 737 )   Save In this article we study the maximal space-like submanifold Mn which is isometrically immersed into locally symmetric pseudo-Riemannian manifold Nn+p p . One main theroem is a sufficient condition for compact Mn to be totally geodesic ones. We also prove a pinching theorem for the square length of the second fundamental form when Mn is complete. References | Related Articles | Metrics

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A new algorithm for constructing soliton solution and its implementation ZHAO Wen-qiang, LIU Yin-ping 2016, 2016 (6):  127-138.  doi: 10.3969/j.issn.1000-5641.2016.06.014 Abstract ( 577 )   HTML ( 16 )   PDF (340KB) ( 836 )   Save Combined with the Painlev´e test, the simple Hirota method was improved. The improved algorithm can be applied to more equations. Based on this method, a software named ZASP was developed with the aid of the symbolic computation software Maple. ZASP can solve nonlinear evolution equation automatically. By applying it to several examples, it can be seen that the program ZASP is an effective and efficient tool for calculating soliton solutions of nonlinear evolution equations. References | Related Articles | Metrics

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Q-spectral characterization of multicones over some regular graphs WU Bao-feng, PANG Lin-lin 2016, 2016 (6):  139-144.  doi: 10.3969/j.issn.1000-5641.2016.06.015 Abstract ( 522 )   HTML ( 6 )   PDF (239KB) ( 595 )   Save The Q-spectral characterization of the multicone graph G ∨ Ks is investigated, where G is a r-regular graph of order n and Ks is a complete graph of order s. We prove that for any positive integer s, the multicone graph G ∨ Ks is determined by its Q-spectrum if r = n−2 and n ≥ 4. We also show that for any positive integer s, if r = n−3 and n ≥ 6, the multicone graph G ∨ Ks is determined by its Q-spectrum if and only if the complement of G has no triangles. References | Related Articles | Metrics

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More efficient CCA-secure identity-based dual receiver encryption CHEN Wen, ZHANG Kai, QIAN Hai-feng 2016, 2016 (6):  145-156.  doi: 10.3969/j.issn.1000-5641.2016.06.016 Abstract ( 504 )   HTML ( 7 )   PDF (413KB) ( 845 )   Save Dual receiver encryption (DRE) is a special kind of public key encryption (PKE), which allows a ciphertext to be decrypted into the same plaintext by two inde- pendent receivers. Though DRE is widely used in scenarios where sensitive information should be potentially decrypted by a supervisor or a third party, the most known DRE constructions in the literatures are obtained from traditional PKE settings. As a result, they have extra overhead for distributions and managements of public key certificates, the identity-based dual receiver encryption (ID-DRE) can reduce overhead. The first identity-based DRE scheme is constructed by an efficient identity-based encryption (IBE). First, we use the CCA-secure (secure against chosen-ciphertext attack) PKE from identity-based techniques to construct a new identity-based DRE scheme with the IND-ID-CCA (indistinguishability against adaptively chosen identity and chosen-ciphertext attack) security, which relies on the bilinear decisional Diffie-Hellman assumption. Then, we extend our scheme to obtain an identity-based dual receiver encryption (ID-DRE) scheme with non-interactive opening, which is the first known identity-based dual receiver encryption (ID-DRE) scheme with non-interactive opening. References | Related Articles | Metrics

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Sampling clock synchronization for OFDM based software-defined radio receivers XIE Ying, HU Xing-bo, XU Wei-yang 2016, 2016 (6):  157-165.  doi: 10.3969/j.issn.1000-5641.2016.06.017 Abstract ( 554 )   HTML ( 7 )   PDF (624KB) ( 628 )   Save The sampling clock error in an OFDM (Orthogonal Frequency Division Multiplexing) receiver will severely degrade the overall system performance. Based on the canonical Gardner loop, a novel sampling clock synchronization scheme suitable for OFDM based software-defined radio (SDR) receivers is proposed, which uses a joint recursive algorithm to track the error and then corrects it by performing asynchronous resampling on the received signal. The proposed error detection method can improve estimation efficiency by eliminating effects of the carrier frequency error while sustaining the loop’s dynamic performance. A dynamic delay technique is devised to control the resampling process, which can smoothly adjust the incoming data stream without sampling disturbance. Theoretical analysis and simulation results indicate that the proposed scheme outperforms other techniques and works well in the multipath channel. References | Related Articles | Metrics

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Research of smart antennas DOA estimation based on wavelet transformer LI Na, YIN Xing-hui, GAO Wen-yun 2016, 2016 (6):  166-172.  doi: 10.3969/j.issn.1000-5641.2016.06.018 Abstract ( 514 )   HTML ( 14 )   PDF (527KB) ( 771 )   Save Having compared two classic smart antenna DOA (Direction of Arrival, DOA) estimation algorithm—delay-sum algorithm, multiple signal classification (MUSIC) algorithm, smart antennas direction of arrival estimation based on wavelet transformer (SADOAWT) algorithm has been proposed. Taking into account the computational complexity and convergence rate, the algorithm converts signal into multiple scales domain, while different frequency domain would use different algorithms. Simulation results show that the computational complexity of new algorithm is low. SADOAWT overcomes the disadvantages of delay-sum algorithm which has low resolution and many sidelobes, it also avoids the problem that resolution of MUSIC algorithm gets reduced while correlated signal coming. References | Related Articles | Metrics

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Analysis of the propagation loss of wireless channel for short range parking system GUO Feng-ming, LI Bing 2016, 2016 (6):  173-181.  doi: 10.3969/j.issn.1000-5641.2016.06.019 Abstract ( 550 )   HTML ( 6 )   PDF (1102KB) ( 704 )   Save The wireless channel propagation efficiency is one of the main factors affecting the short range parking system (SRPS) performance. A channel propagation loss coefficient of SRPS is defined for cars, and a propagation loss model based on two-ray model is established. Simulation and measured results show that antenna polarization mode and frequency-influenced path loss is minimum, when tag is along the microwave skylight in car windshield; as tag identification range is less than 10 m, the vertically polarized wave loss is mutated by ground electromagnetic wave reflection. In order to make successful tag identification, the height of the reader antenna should be above 1.18 m. References | Related Articles | Metrics

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Grain size characteristics of the surface sediments from the Qian Tang River Estuary and their implication for sedimentary hydrodynamics LIU Zhao, SHI Yu-xin, DAI Xue-rong, XI Ya-juan 2016, 2016 (6):  182-191.  doi: 10.3969/j.issn.1000-5641.2016.06.020 Abstract ( 717 )   HTML ( 27 )   PDF (2692KB) ( 1151 )   Save The Qiantang River estuary is a typical funnel shaped, strong tidal estuary.  It extends 274 kmlong from the tidal limit (at Luci) down to the mouth of Hangzhou Bay and possesses a complicated sedimentary hydraulic environment. This paper focuses on the grain size analysis of the surface sediments (68 samples in total)taken from the near bank underwater bottom. The grain size characteristics,types of sediments and their spatial distribution and the possible causes are discussed. Studies  have shown that the sediments are mainly composed of silt and clayey silt. According to grain size composition,the estuary can be divided into three parts: the upper, middle and the lower. The sediments from both the upper and the lower parts are finer, poorer sorted than those from the middle part.The skewness parameter (SK) is featured with sub symmetric positive bias in the upper part, while  very positively skewed positive bias in the lower part. From upstream to downstream the frequency curve shows different peak types of multipeak, high and narrow peak and low narrow peak. These differences in sediment composition and textures must have matched the different sedimentary hydrodynamic environment: the runoff in the upper part, alternative of runoff and  tide in the middle, and mainly the tidal environment in the lower. As indicated by Pejrup triangulation, the hydrodynamic environment of this estuary is relatively strong, especially in the middle part, and the grain size characteristics show close relation  to the hydrodynamic  environment. References | Related Articles | Metrics

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Predictions of suitable distribution of Meteorium in China under climate change LIU Yan 2016, 2016 (6):  192-202.  doi: 10.3969/j.issn.1000-5641.2016.06.021 Abstract ( 628 )   HTML ( 15 )   PDF (1500KB) ( 847 )   Save According to 166 geographic distribution records of six Meteorium species and 19 bioclimatic variables, the present study employed both Maximum entropy (Maxent) model and the spatial analysis methods in the ArcGIS 10.2 to predict the potential distribution of Meteorium in China and compare the range size of each projection under different climate scenarios, in order to provide scientific evidence of the impact of ongoing climate change for bryophytes’ distribution. The results showed that temperature annual range, mean temperature of coldest quarter, temperature seasonality (standard deviation *100) and max temperature of warmest month were the major factors influencing the distribution of Meteorium in China. Under current climate condition, the suitable distribution of Meteorium located in large parts of southern Qin Ling and Huai River. While in future climate scenarios (i.e. 2050s and 2070s), both of the ranges were predicted to decrease slightly. It will become 94.48% and 95.78% of the current suitable area in 2050s and 2070s, respectively. References | Related Articles | Metrics