Table of Content

20 January 2010, Volume 46 Issue 1

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Effect of Pierced Enclosure on Wind Pressure on Building Surface

CHEN Kai,WEI Qingding,ZHU Fengrong,LIANG Bin

2010, 46(1):  1-6. 

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The pierced enclosure outside the glass curtain wall can affect the wind pressure on building surface. The results of wind tunnel test show that the basic pressure distributions on the glass curtain wall isn't changed, although the pressure value is affected by the additional pierced enclosure. It has significant influence on the region close to the edge of pierced enclosure due to the change of the position of flow separation. Under the condition of porosity 55% ,the average pressure is reduced by 10% when the pierced enclosure is on the windward side or in the region where flow separates; while the pressure is increased slightly when the pierced enclosure is on the leeside. The fluctuating pressure is reduced by 10% due to the weakening of turbulent energy by pierced enclosure. In conclusion, the pierced enclosure has positive influence on the safety of the glass curtain wall.

Phase Diagram of an Ultracold Homogeneous Spin-Polarized Fermi Gas around the Tricritical Point at Resonance

XU Guanjie,YU Zengqiang,YIN Lan

2010, 46(1):  7-11. 

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The phase diagram of a homogenous ultracold Fermi gas with spin polarizationis studied at unitarity. In the framework of Landau's phase-transition theory, the thermodynamic grand potential is expanded to the sixth order in the order parameter, and coefficients of each order are determined. The tricritical point in the temperature-polarization plane is obtained. Abovethe critical point, the second-order phase-transition line between the super fluid and the normal phase is determined. Belowthe critical point, there is a phase-separation region between these two phases, and the first-order phase-transition line is obtained.

Ni-Enhanced Photoluminescence of Er³ Dopedin Si-Rich Nitride

SUN Kai,XU Wanjin,RAN Guangzhao

2010, 46(1):  12-16. 

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Er-doped Si-rich nitride ( SRN ∶Er) films and three-period superlattices of SRN ∶Er Ni were deposited by reactive magnetronsputtering technique and annealed at 1100 ℃. The photo luminescence spectra of SRN ∶Er films show two emission bands, one centered at 665～750 nm and another peaked at 1. 54μm, where the 665～750 nmone is due to Si nanocrystals in SRN and the 1. 54μmone is characteristic for Er3+. The photo luminescence spectra of the super lattices exhibit fine structures of 3 + Er light emission around 520, 550 and 850 nm and a 12-fold enhanced Er light emission at 1. 54 μm. The appearance of these fine structures indicates that the local environments around Er3 + become ordered and Er3+ is much more optically active in such ordered environments than in SRN ∶Er films. Raman-scattering spectra measurements demonstrate an increase in the number of Sinanocrystals. Therefore, the 12-fold enhancement at 1.54μmis a result of the enhancement in the Er3+ optical activation and the increase in the number of Si nanocrystals .

A HIT-Based Semantic Search Approachin Unstructured P2P Systems

XU Quanqing,DAI Yafei,CUI Bin

2010, 46(1):  17-29. 

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An effective semantic search approach based on hierarchical interest tree ( HIT) is proposed in unstructured P2P systems. Documents owned by a peer are classifiedinto categories to build a HIT, which is sent to a super peer. Meanwhile, the inverted document index (IDI) of top n ter ms for each category is also sent to a super peer according to their Chi-square (χ²) statistic values. When a regular peer sends a query and gives a category semantic similarity threshold Simth, query messages are forwarded via an effective query routing algorithm and the results are returned by searching HIT. It is flexible for each peer since it can set the Simth, which can provide a better personal service. The experiments showthat HIT-based semantic search approach is more accurate and efficient than previous methods.

Research and Simulation Modeling on Gray Zone in Wireless Ad-Hoc Network

LIU Zhi min,ZHANG Weihua,XU Yingqing

2010, 46(1):  35-40. 

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The authors analyze the cause of gray zone and its influence over network performance. A modeling method of gray zone based on NS2 simulation platformis proposed. Compared to traditional models, its simulation results are more close to real scene. This model reflects the gray zone problemin real Ad-Hoc network and provides a model support on NS2 simulation platform for link failure detection algorithm and routing selection algorithmof Ad-Hoc network.

PLC Program Verification and Analysis Using the COQ Theorem Prover

CHEN Gang,SONG Xiaoyu,GU Ming

2010, 46(1):  30-34. 

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The authors analyse a PLC competition quiz machine program and proves a set of properties using the COQ theorem prover. These properties reveal that only half of output states would be reachable and describe the transition relation over these states in an abstract way. Based on theseresults the author sintroducethe notion of logic automata as a complete description of this PLC program. The authors also point out that the program may produce unfair response in rare situations.

Improvement of the Interactive Performance Isolation of Virtual Machines on Xen Platform

XIA Yubin,YANG Chun,NIU Yan,CHENG Xu

2010, 46(1):  41-47. 

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The authors address the problemthat in a highly-consolidated environment, there are continuous peaks of network latency of guest OS. Three optimizations of VM scheduler are designed and implemented to improve interactive performance isolation, including cooperative preemption, preempt-back and accurate accounting. None of these optimizations needs guest OS to be modified. The evaluation results show that with 8 computing-intensive VMs running concurrently, the average of top 5% network latency of other 8 VMs is reducedto as mush as 0.93% of the original one, and the one of web-mail browsing by Firefox is reduced to 56.1%.

A New Baseband Decoder for Mobile RFID Reader

ZHONG Jinsi,WANG Xinan,FENG Xiaoxing,CAO Wei,QI Yongzhen

2010, 46(1):  48-54. 

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A digital baseband receiver which supports both ISO 18000-6B and 6Cfor UHF RFIDradio frequency identification reader is described. The digital baseband receiver includes deci mation filters, dc-removed filters, phase-recovery module, and so on. A novel decoder in digital baseband is also proposed. An approach to compensate the effect of zero-point excursion based on the zero-detect method is presented in the decoder. Simulation and verification results indicate that the new approach needs less hardware resources and less time to decodethe signal, compared with the correlation based demodulation method. Total chip area without test pads is 730 μm ×3375 μm @0. 18 μm CMOSprocess and consumes 32. 89 mW, whilethe decoder occupies the 1% of total area and consumes 0. 23mW.

Microarchitectural Design Space Exploration via Support Vector Machine

PANG Jiufeng,LI Xianfeng,XIE Jinsong,TONG Dong,CHENG Xu

2010, 46(1):  55-63. 

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The authors propose an approachto reducethe number of required si mulations, simulate on sampled design points, and use it to construct informative and predictive support vector regression models. Having captured the interacting effects of design parameters, the models predict outputs for design points that are not simulated. The prediction time of model can be negligible compared with detailed simulation. The optimal design point determined by prediction is very close to that of simulation for most applications and provides an efficient wayto cull huge design space. Trained on only 0.26 % design points, the models yield mean relative prediction error as low as 0 .52 % for performance and 1 .08 % for power. Correlation analysis demonstrates that prediction output is highly correlated with simulated observation. The average squared correlation coefficient is 0.728 for performance models while 0.703 for power models, which implies that support vector regressions capture most of relationships among design parameters. The model also provides a predictive probability interval for each prediction, which is informative for computer architects.

An Adaptive Traffic Flow Prediction Mechanism Based on Locally Weighted Learning

SHUAI Meng,HAN Lei,XIE Kunqing,SONG Guojie,MA Xiujun,CHEN Guanhua

2010, 46(1):  64-68. 

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The authors propose an adaptive neighborhood adjusting mechanism based on certain domain knowledge, namely three phrase traffic theory. The training dataset is divided into three subsets, in which corresponding neighborhood sizes are generated. In the estimation process, the authors make predictions on data at different traffic state with respective locally weighted learning models whose kernel bandwidths are different. The final prediction is a combination of all the previous predictions. Experiments based on real traffic data prove that the proposed method can improvethe forecasting accuracy.

Retrieving Atmospheric Water Vapor Profilesinthe North-West Pacific Using AMSU Measurements

WANG Xi,SONG Guoqiong,YAO Zhanyu,LI Wanbiao

2010, 46(1):  69-78. 

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Radiative transfer model for ATOVS (RTTOV) is used to simulate advanced microwave sounding unit (AMSU) channels’sensitivityto water vapor profile ; some of channels are eliminated step by step to establish two retrieving algorithms; and then retrieving matrixes are calculated and applied to retrieve water vapor profiles frombrightness temperatures in July 2006 from AMSU instrument aboard national oceanic and atmospheric administration (NOAA)-16. Compared with reanalysis humidity profiles formnational centers for environmental prediction (NCEP), root mean square(RMS) at 0600UTC and 1800UTC at every single level are within 1. 4g/kg and 1. 7g/kg , respectively. Retrieved water vapor profiles generally agree with NCEP ones ; retrieved products can locate the cloud area and water supply of Typhoon; it can describethe structure of Typhoon at some level.

An Observation Study of Turbulent Flux Measured on Tower in Hilly Area, Central China

WANG Xue,CAI Xuhui,KANG Ling,ZHANG Hongsheng,SONG Yu,CHEN Jiayi

2010, 46(1):  79-86. 

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An observation tower was erected on Xiaomo Mountain, Hunan Province. Besides the collection of turbulence information, routine meteorological data were collected during 2006. Diurnal variances of wind and temperature profiles in winter and summer were analyzed as well as seasonal variances of wind speed and wind direction. Furthermore, sensible heat fluxes calculated using classical flux-profile relationship (H_c) are compared with the directly measured values (H_m) . It is found that the complexterrain around the tower has a distinct impact onthe values of roughness length z₀ and calculated sensible heat flux (H_c); therefore it is necessaryto divide the data into 2-3 groups according to the wind directions. The following analysis show that z₀ in the south part of the tower is much higher because of the hilly terrain, and the mountain slope affects the sensible heat flux remarkably. When upslope wind blows, the value of H_c is higher than H_m, and vice versa. Since the trend of the mountain is southwest-northeast, the value of H_c is similar to H_m whenthe windis fromsouthwest. Finally, H_c is corrected and the agreement between H_c and H_m is largely improved.

Ultra-Low Frequency Electromagnetic Wave Exploration to the Active Faults in Hohhot

YAO Weihao,HOU Guiting,GUO Wensheng,LIU Xida,WANG Shuyuan,SUNJing

2010, 46(1):  87-95. 

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Hohhot region is the high intensity earthquake zone due to the growth of a number of active faults. The ultra-low frequency electromagnetic detection method is used to study active faults in the region, through high-precision processing of detecting data and precise image interpretation. By usingthe above technology, the location, the displacement, the nature and the activity of the main three faults are clarified to serve for the urban planning, earthquake disaster prevention and mitigation in Hohhot. The difference between the maximum and minimum displacement of Dahei River fault is 110m, which are 60 mof Xiaohei River fault and 64 mof Xinhua Square fault. These data show that the Dahei River fault is the most active fault at the end of Neogene period.

Quartz Grain SEM Microtextures Analyses of Sub-Glacial Deposits at Hailuogou Glacier

SHI Lei,ZHANG Yue,CHEN Yixin,FU Hairong,LIU Gengnian

2010, 46(1):  96-102. 

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The SEM microtextures of glacial sediments samples taken from Hailuogou Glacier are analyzed. The major microtextures are listed as follows: sharp angular features with sharp edges and high relief; large-medium conchoidal fractures, parallel cleavage and terraced fractures, indicating mechanical fragmentation; stria, crescentic gouges and crushed deep hole, indicating abrasion; dissolution pits and grooves, siliceous sphere and clay minerals, indicating chemical dissolution and precipitation. These results indicate that there are intensive erosion processes and chemical dissolution processes under Hailuogou Glacier. The statistical analyses show that the quartz grain SEM microtextures of maritime glacial deposits are different fromthat of fluvial, lacustrine, coastal and eolian deposits, as well as that of continental glacial deposits in Antarctic and inside Tibetan Plateau.

Hydrocarbon Generating Potential and Mode of Late Per mian Coal fromPanxian, Guizhou Province

WANG Zhen,GUO Huaicheng,SUN Xuguang,ZHANG Rui

2010, 46(1):  103-108. 

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Organic geo-chemical methods were utilizedto simulatethe hydrocarbon-generation modes of coal samples fromGuizhou Province. High temperature simulation experiment by quartz cuvette technique and microscope analysis by FTIR were utilized to estimate hydrocarbon-generation mode and potential of local coal mine in Panxian, Guizhou Province. The results indicate that, the kerogen of Panxian coals is of Ⅲtype; the heating product is mainly gas because of the simple component of kerogen; and the mass hydrocarbon producing temperature is about 300-350 ℃.

A Landmark-Based Linear Referencing Method

GAO Yong,ZHANG Jing,ZHANG Yi,LIU Yu

2010, 46(1):  109-114. 

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The traditional linear referencing methods utilize network nodes as the references, but positioning and way finding in linear networks are always referenced by landmarks in common sense. Based on landmarks, a new linear referencing method is presented. Landmarks are adopted into alinear network by defining their projections to substitute network nodes as the referenced originpoints. And a landmark-based network Voronoi diagramis constructed. Then any point on the network can be linear referenced relatively by its Voronoi generator using a pair of the neighbor landmark and their shortest path. This landmark-based linear referencing method is proved sound, complete, and unique except the boundaries. It is coordinated to the human’s commonsense spatial cognation and straightforward to be understood and utilized. This method can also support many complex GIS applications such as route cognition, wayfinding, k-nearest neighbor search, and retail stores analysis, etc.

Derivation of the 2ⁿ Rulefromthe Rank-Size Rule of City-Size Distribution

CHEN Yanguang,HU Yuwang

2010, 46(1):  115-120. 

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This paper demonstrates the equivalent relation between the 2ⁿ rule of hierarchy of cities and the rank-size rule of city size distribution. According as the rank-size rule, if the largest city P₁ = 1 , then the size of the kth city by rank P_k will be 1?k. Thus city sizes can be abstracted as a harmonic sequences, {1 k}. Grouping the harmonic sequences into many classes in atop-n down way according to the 2 principle yields a hierarchy of fractions with cascade structure . In this instance , the interclass number ratio is r_f = 2. Thetotal population of the first classis 1, second class, 1 2 + 1 3 ≈0. 8333, thethird class, 1 4 + 1 5 + 1 6 + 1 7 ≈0. 7595 , and so on. If the sequence number of a classis large enough, it will have total population approaching to ln2 ≈0. 6931 in theory . By limit analysis, the mean size ratio of two immediate classes is close to r_p = 2. Accordingly, the fractal dimension of the cascade structure is D= lnr_f lnr_p →1. However, the first several classes depart fromthe scaling range to some extent theoretically. As for the empirical data, the last class always goes beyondthe scalingrange because of undergrowth of small cities andtowns. Therefore, the exponential laws andthe power laws of hierarchy of cities are al ways invalid at the extreme scales, i .e . the very large and small scales. Key words 2 n rule ; rank-size rule ; Zipf’s law; fractal ; hierarchy of cities ; cascade structure ; symmetry

Simulation Research on Matching Algorithmfor Underwater Gravity Difference Entropy Aided Inertial Navigation

ZHANGFeizhou,CHEN Jia,GENG Jiazhou,CHENG Peng

2010, 46(1):  136-140. 

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The task modes of underwater gravity assistant navigation and design of system simulation algorithm are studied with gravity difference entropy of physical geography character. The basic principle of the algorithmis that the information entropy could be used in gravity assistant navigation for autonomous underwater vehicle(AUV) in navigation matching algorithm. The error of inertial navigation systemin AUV is corrected by means of the information difference between template gravity map and actual gravity map and the difference of gravity gradient maps, therefore the high precision navigation can be implemented in the condition of long time and covered operation. The character and development general situation of gravity assistant navigation are also inducted. On basis of gravity base research, the design idea and experiment method of passive navigation matching algorithm based on underwater gravity difference entropy are expatiated in the end.

Study on Optimization of Urban Passenger Traffic Environmental SystemBased on Trip

LIU Hui,GUO Huaicheng,YU Yajuan,WANG Zhen,LIU Tao

2010, 46(1):  121-128. 

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An optimization model was developed for urban traffic environmental system based on passenger trip generating.Firstly, a System Dynamic model was built up to simulate the developing characteristics of urban passenger traffic system, as well as its environmental impacts. Secondly, a linear optimization model, with the objective of maximizing traffic efficiency under the resource and the environment constrains, was formed to search for the best trip assignment structure. Thirdly, several scenarios were designed based on the results of the two former models and amending effects were re-simulated. Finally, grey correlation assessment was utilized on the premise of social-economic support, feasible policy, minimized pressures on resource and environment, to select the optimized assignment structure. Acase study of Beijing wasfollowed andtheresults verified the mode's effectiveness.

Construction of Rural Environment Multi-Agent Simulation System: Application of Agricultural Household Model on Rural Environmental Management

YANG Shunshun ,LUAN Shengji

2010, 46(1):  129-135. 

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In view of the problems happened in China rural environment and the usage of agricultural household model to analyze rural environment, this research developed a Chinese rural economy-environment evaluation system,SFRE, based onthe complex adaptive systemtheory with the aid of SwarmTool. The SFRE system, which integrated econometrics, statistics and the pollutant discharge model effectively, could emerge the macroscopic phenomenon by the activities of microscopic agents ? “the virtual agricultural household”. Besides, the authors elaborated five main model assumptions and the agent rules , and summarized the designing approaches about four subsystems of the rural production, consumption, social environment and environmental assessment. It is an initiative attempt as a multi-agent based model for studyingthe rural economics completely and assessing rural environmental changes.

An Empirical Research onthe Theoretical Construct of Chinese Core Self-evaluation

CHEN Hui,GAN Yiqun,WEN Yao,LIU Xin,SUN Jian

2010, 46(1):  141-146. 

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The present study presents preliminary empirical evidence for a hypothetical construct of Chinese core self-evaluation proposed by Gan, et al ( 2007) . Three hundred and thirteen Chinese joint venture employees completed the Qingnian Zhongguo Personality Scale (QZPS) and other questionnaires. Results indicate that Chinese core self-evaluation, which is composed of Collective self-esteem, Kindness, Talents, and Ways of life, had significant correlations with job outcome variables. These four traits had an average validity of 0.29 on job performance, and the factor analysis provides preliminary evidence for a theoretical construct of Chinese core self-evaluation.

Science and Technology Parksin China : AnInnovation Cluster Perspective

WANG Jici,CHEN Ping,MA Mingbo

2010, 46(1):  147-154. 

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This paper briefly analyzes the characteristics and evolution of the Science and Technology Parks in developed countries and in China, irrespectively. Compared with the former, China's state-level Science and Technology Parks have more complex context and more problems in development process. China's high-tech industry has grown quantitatively in various aspects.However, the industry as a whole is still at the low-end of the global value chain. With an innovation cluster perspective, the paper proposes the ideal development path of the Science and Technology Parks of China. The implication of innovation cluster, the importance of institution for collaboration and the influence of global driven force are explained.