Table of Content

20 March 2013, Volume 49 Issue 2

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Electrically-Pumped Metal-Organic-Metal Plasmonic Emitter

LI Hongqiang,WANG Chong

2013, 49(2):  171-175. 

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A metal-organic-metal (MOM) plasmonic emitter with the p-type Si substrate and the active layer of Alq₃: DCM is reported. The device structure is p-Si/Au/V₂O₅/NPB/Alq₃:DCM/Sm/Au. The optical image of edge emission indicates that most of the light is well confined to the MOM waveguide. Light is collected with a confocal μ-Raman spectrometer. The TM mode is more intense than the TE mode by a factor of 2, which can be attributed to the contribution of surface plasmon polariton (SPP). The power dissipation spectrum is computed based on a simplified MOM structure of Au/organic/Au. By integrating the power of the SPP modes in the spectrum, the fraction of the total power coupled to SPP modes is 65%. The electric-field-intensity distribution and the loss coefficients are computed by finite-different time-domain (FDTD) method.

High Resolution SAR Image Segmentation Using Improved PCNN

WANG Huazhang,ZAI Wenjiao

2013, 49(2):  176-182. 

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An improved PCNN (pulse coupled neural network) model of SAR (synthetic aperture radar) image segmentation was proposed, which aimed at the characteristics of strong noise and difficult segmentation for high resolution SAR image. At first, it used a complex wavelet to reduce noise according to SAR image speckle noise characteristics. Then, it improved and simplified the input signal, especially for the link coefficient and decay factor of threshold based on traditional PCNN model. It gave a theoretical approximate derivation and reduced the artificial setting of parameters. Finally, it adopted the appropriate threshold to quantify the segmentation result to get binary image of object. The experimental results show that proposed algorithm improves the operational efficiency and enhances adapting ability. Compared with traditional methods, the regional consistency is improved by 0.013, the contrast of the region is improved 0.015. The proposed PCNN model is superior to the traditional PCNN algorithm and can provide a new strategy for high resolution SAR image segmentation.

Non-rigid 3D Shape Retrieval Based on Automatic Anti-articulating

WANG Xulei,ZHA Hongbin

2013, 49(2):  183-190. 

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The authors propose a new non-rigid 3D shape retrieval method based on automatic anti-articulating. First, feature points are extracted on the 3D shape, and then are used in shape partition and skeleton extraction. Then, the mesh editing technique is employed to automatically regularize the articulation, in order to generate a rigid 3D shape without deformation, which is used as the isometry-invariant canonical form. Finally, shape descriptors are constructed on the canonical form, and Earth Mover’s distance is employed to measure the intrinsic similarities between non-rigid objects. The method introduces less geometric distortion and requires much less computational cost. Experimental results demonstrate a significant performance improvement in retrieving non-rigid 3D shapes.

A Novel Algorithm for Video Zooming

CAO Xixin,LIU Jing,WU Shuai,ZHANG Qihui,LIN Jinlong,WANG Ping

2013, 49(2):  191-196. 

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Inspired from the quantum mechanics, the authors propose a novel and practical video zooming algorithm which has a better image quality than other methods. Compared to the quantum mechanics models , an image is treated as a energy field and modify the traditional cardinal spline function. This method reduces the sample effect across the edges and improves the human pleasure. The proposed method has a low complexity, and keeps the coherence between frames for video sequence. It is especially suit for the embedded equipments such as mobile phones and PDAs.

A Novel Algorithm for the Video Caption Extraction

CAO Xixin,LIU Jing,YANG Xudong,WU Shuai,ZHANG Qihui

2013, 49(2):  197-202. 

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The authors propose a novel algorithm for the video caption extraction. By using the image sharpening method, a better extraction effect can be achieved for the special video sequences. The caption area and the non-caption area can be efficiently separated by neighborhood average operation. A projection algorithm is proposed to implement on a better decomposition and extraction based on the statistical characteristics, and this can efficiently separate the caption area and make the extraction coordinates more precise. The experiments show that the proposed algorithm has a better effect compared with the original methods. Because of the low computational complexity, it can be widely used in the field of video image processing.

Positional Language Models with Semantic Information

YU Wei,WANG Mingwen,WAN Jianyi,ZUO Jiali

2013, 49(2):  203-212. 

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Because positional language models did not consider semantic relationship between the words in different positions, the authors present an effective model named “positional language models with semantic information”. Firstly, the authors use Gaussian kernel function to measure the position relationship between words. Secondly, the authors present a technology which is named “smoothed mutual information” to measure semantic relationship between the words, and also prove that smoothed mutual information can effectively solve the problem that a large number of two words could not calculate the transition probability between them only by mutual information. Then the authors prove that positional language models are a special case of positional language models with semantic information. Finally, applying this new model to the area of information retrieval can obtain a retrieval model based on the new model. The experiment show that the retrieval model based on the new model performs better than a retrieval model based on positional language models for using in information retrieval.

A Parsing Approach for Verbose Queries

YAO Lan,LIN Hongfei,LIN Yuan,MA Yunlong

2013, 49(2):  213-218. 

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The authors extended the traditional “bag of words” idea. Every document was regarded as “bag of sentences”. The dependency relationship of the words was obtained from the “bag of sentences” and verbose queries by dependency parsing. According to the matching degree of the dependence relationship, the similarity scores between verbose queries and documents was obtained. Finally, the initial results were re-ranked. Experiment on a standard TREC corpus shows that new approach can improve retrieval effectiveness for verbose query and the low recall rate. For the low recall rate, the MAP and P@N have a significantly improvement.

A Document’s Placenames-Aware Document Ranking for GIR

REN Kejiang,ZHANG Shaowu,LIN Hongfei

2013, 49(2):  219-226. 

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In order to induce the negative impact of irrelevant place names on geographical relevance, the authors proposed a geographic information retrieval (GIR) ranking method to reduce the impact which was based on document placenames-aware. Proposed method was not fixed on a MBR(minimum bounding rectangle), but all of the placenames which appeared in a document would calculate the relevance with query scope respectively. Experimental results show that the proposed approach can outperform baselines which are based on determining the MBR’s model and pure textual model of tf-idf.

Assessment of COSMIC Radio Occultation Retrieval Product

WANG Borui,LIU Xiaoyang,WANG Jiuke

2013, 49(2):  241-251. 

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The retrieval product of COSMIC (constellation observing system for meteorology, ionosphere, and climate) radio occultation sounding system was verified using the Chinese radiosonde from 2007 to 2010. The horizontal distance between radiosonde station and the occultation event is within 100 km, and the time window is 1 hour. The comparison is performed from 925 hPa to 10 hPa. Result shows that the temperature of COSMIC agrees well with Chinese radiosonde. The mean temperature bias is ?0.08 K, and the standard deviation is 1.67 K. The water vapor pressure of COSMIC has notable systematic bias from radiosonde on layers above 200 hPa. On layers below 200 hPa, the mean absolute deviation of specific humidity is about +0.080 g/kg, and the standard deviation is about 0.692 g/kg, the mean relative error of water vapor pressure is about +69.6%, and the standard deviation is about 160.0%. The COSMIC quality control process fails to detect some extremely small humidity data which causes large relative error. Here also provides a comparison of 6 radiosonde types with COSMIC product. As result is affected by the background bias from radiosonde which differs on different regions, the COSMIC retrieval product could be used as benchmark if precision requirement is not strictness.

A Fast Watermarking Algorithm with Low Complexity Error Compensation in H.264/AVC Bit-Stream

ZHANG Liwei,ZHU Yuesheng,Po Lai-man

2013, 49(2):  227-233. 

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Watermarking algorithms in the H.264/AVC bit-stream are more efficient, but the propagation error introduced would decrease the visual quality severely. In order to reduce the computation complexity of compensation, a new error compensation method is proposed, in which the watermark is embedded into the quantized DCT coefficients and the propagation error gained by a low complexity error prediction module are compensated adaptively. The simulation results show that with the proposed compensation method, a real time video watermarking can be realized, with the features of low complexity, high PSNR and less bitrate increase.

Event Ontology Model and Event Class Ranking

ZHONG Zhaoman,LIU Zongtian,LI Cunhua

2013, 49(2):  234-240. 

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The authors define an event and an event class, and illustrate the relations between event classes. Then event-oriented ontology model is constructed, which will contribute new methods and technologies to semantic-based knowledge processing. Furthermore, taking event class ranking as an example based on event ontology, the method of HARank-based event class ranking is introduced for event ontology, and corresponding experimental and evaluating results are presented. In comparison with conventional methods, event ontology represents knowledge with a higher granularity, and it will be more suitable for the representation of the knowledge about the movement and state changes in the real world.

Comparative Analysis of Detection Methods of Non-stationarity in Time Series

LI Qinglei,MA Nan,FU Zuntao

2013, 49(2):  252-260. 

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Two methods are applied to detect non-stationarity in time series. One is the run-test (RT) method, which depends on statistic theory; the other is a graphical method called space time-index (STI), which is a dynamical method. Three different RT methods and STI method are given to detect the non-stationarity in artificial time series with known non-stationarity and experimental turbulence time series measured in atmospheric boundary layer. The results show that the RT method which has lower accuracy is simpler and more efficient than STI. Besides comparing the merits of the STI and RT methods, the results also show that the variance RT method is the most effective to detect the non-stationarity in experimental turbulence time series among the three ones of RT methods.

Analysis on the Policy of Phasing out High-Emission Vehicles in Beijing

ZHANG Xiuli,WU Dan,ZHANG Shiqiu

2013, 49(2):  297-304. 

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Because of the motor vehicle emissions high contribution on atmospheric air pollution in Beijing, the vehicle control policies need to be shift with the target of emission reduction. Based on the analysis of Beijing motor vehicle composition and pollution contribution, this paper presents the measure of phasing out high-emission vehicles. This measure directly controls the high-emission vehicles which have contributed most motor vehicle pollution, to maximize the environmental effects while controlling the same amount of vehicles. Comparing this measure with the measures of “controlling the new vehicles increasing” and “driving restriction”, the measure of phasing out high-emission vehicles has the highest cost-effectiveness ratio and it has significance effect in Beijing air pollution controlling and in achieving the twelfth “five years” NOx emission reduction targets. Considering the factors of the damage cost of the high-emission cars, the willingness to accept (WTA) of the owners of the phased cars, the incentive direction of the subsidies and the government budget, the authors propose that the subsidy standard would be a single one and the level of subsidy should be about 4000?6000 yuan per vehicle. Phasing out high-emission vehicles has multiple advantages: reflecting the cost-effectiveness of policy design, reflecting the policy direction of being responsible for the environment and the incentive effects of economical instruments.

A Parameterization Scheme of Water Vapor Profiles over Beijing Based on Radiosonde Data

LIANG Zhi,XU Wanyun,HUANG Mengyu,LIU Xiaoyang,ZHAO Chunsheng

2013, 49(2):  261-268. 

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Radiosonde (RS) data over Beijing in 2008 was employed to analyze vertical distributions of water vapor in this area. A parameterization scheme of water vapor profiles is proposed according to different conditions of Planetary Boundary Layer (PBL). In the condition of Stable Boundary Layer (SBL) or shallow boundary layer, the parameterization scheme of water vapor profiles can be formulated by q=q₀e^z/2624, here q₀ is specific humidity at surface. In the condition of Convective Boundary Layer (CBL), the vertical distribution of water vapor is significantly influenced by CBL. The parameterization scheme of water vapor profiles can be expressed as 1) within the CBL (0≤ z0; 2) near the top of CBL (|z-PBL|<200), q=q₀(A-B(z-PBL)); 3) above the CBL (PBL+200≤z), q=Cq₀(z-5000-PBL), here z is height (unit is metre), PBL is the height of PBL (unit is metre). A=0.72, B=1.4×10^-3m^-1, C=?9.17×10^?5m^-1. For CBL, the IWV would be underestimated by 10% using the exponential distribution. A better estimation is achieved with this parameterization scheme proposed.

Relationship Between Gas Accumulation and Structural Characteristics of Extensional-Shear Fault System in Yakela Fault Block

YANG Shengbin,LIU Zhongbao,GENG Xinxia

2013, 49(2):  269-276. 

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Through interpretation of 3D seismic data, the extensional-shear fault system in the Neogene in Yakela fault block has two main features of blocks distributed along east-west and zones distributed along north-south, which develops four fault structural styles, including stepladder fault structure, tilted fault block structure, graben-horst block structure and negative flower shaped structure. There are four trap structural styles associated with extensional-shear fault system, namely fault nose and faulted anticline, tilted fault block, reverse drag anticline and horst. The traps formed by the extensional-shear faults, whose main active period are Suwiyi-Jidike epoch of neogene, well match the periods of hydrocarbon formation reservoirs. The hydrocarbon vertical migration along the extensional-shear fault appears clearly in the process of hydrocarbon accumulation in Cretaceous and Tertiary, but lateral sealing of the extensional-shear fault is vital in the process of pools of petroleum accumulation.

Volcanic Debris Flow: A New Type of Lower Cretaceous Reservoir in Hailar-Tamtsag Basin

LI Xiaomin,SHI Yongmin,JIANG Hongfu,WANG Lei,QIN Xiaoshuang,WU Wenjuan,CHAI Zhi

2013, 49(2):  277-287. 

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The lower cretaceous oil-bearing reservoir of Hailar-Tamtsag basin is composed of several NNE trending volcanic rift basin group during the early cretaceous. In the early phase, large-scale volcanic debris flow sediment filled in the lacustrine basin center where the source was prolific, which then caused the formation of endogenous volcanic debris flow oil and gas reservoirs that became a new and major reservoir type in the basin. The petrology experiments suggest that the combination of lithology in this reservoir is different from the usual pyroclastic rock such as “tuffaceous sandstone” and “tuff glutenite”. Its mixed facies are caused by rapid accumulation of volcanic debris flow with specific sedimentary origin and paleogeographic environment, which is also a new type of reservoir sedimentary origin on which there is less domestic and international research. The characteristics of this reservoir includes mélange accumulation of tuff and normal glutenite, complex types of pore space, strong water-sensitivity, low permeability, fast change of facies, strong heterogeneity. Since the reservoir is a special type of reservoir with unstable physics and chemistry, it has strong sensibilities and weak cementation, which likely causes strong water-sensitivity, speed-sensitivity, casing damages and deformations, sand productions, and the development is difficult. The investigation of the genetic mechanism of volcanic debris flow reservoir will provide the theoretical basis for optimizing the development method, making rational policy and exploiting economically and effectively.

Research on the “Grazing Ban” Policy’s Effect to Grassland Quality: Analysis on the Scale of Herdsman Households

GU Yuchen,LI Wenjun

2013, 49(2):  288-296. 

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In order to conduct comprehensive analysis of “grazing ban” policy and its impacts, the authors applied NDVI data with MODIS satellite information to analyze the impacts of “grazing ban” policy on vegetation biomass with 8 years of NDVI data comparison between grazing and non-grazing pasturelands in New Barag Right Banner. At the same time, semi-structure interviews were conducted with herder families to reflect their reaction towards the policy impacts. The results indicate that even though there are relatively small differences in the biomass production between grazing and non-grazing pasturelands, the differences are not obvious enough to influence decisive policy implementation. In addition, the findings demonstrate that the level of rangeland biomass production has been highly fluctuated within 4 year duration after the “grazing ban” policy implementation. Therefore, it does necessarily approve that “grazing ban” policy has improved overall grassland quality. As matter of fact, the policy implementation has disturbed the original interaction between livestock and grassland ecosystem, and thus it may impose negative effects on the rangeland quality.

Effects of Long-Term Addition of Lead on the Physical and Chemical Properties and Performance of Aerobic Granules Sludge

LIU Yong,HAN Peng,XU Nan

2013, 49(2):  305-310. 

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The research mainly focused on effects of long-term addition of lead on performance by physicochemical index and stability of aerobic granules sludge system. Results show that removal of phosphorus was affected significantly when the theoretical concentration of lead was 10 mg/L, and the removal efficiency decreased from 50% to 28%. When the concentration of lead had a further increasing, the phosphorus removal rate declined further, and finally maintained at about 18%. Removal efficiency of NH4-N began to decline when the theoretical concentration of lead was up to 50 mg/L, and finally maintained at about 80%. At the same time, the MLSS decreased, SV30 increased, SVI rose sharply, aerobic granular disintegrated gradually and settling charac- teristics deteriorated; but removal of COD increased from 87% to 93% within the range of 1?50 mg/L.

NDVI-Based Spatial-Temporal Change in Grassland Growth of China from 1982 to 2010

LIANG Shuang,PENG Shushi, LIN Xin, CONG Nan

2013, 49(2):  311-320. 

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The authors used remote sensing data (NOAA-AVHRR) and took the Normalized Difference Vegetation Index (NDVI) as an indicator of vegetation growth to explore the trends of grassland growth and their dynamic responses to climate change from 1982 to 2010. Overall, during the 29 years, the national averaging growing season NDVI significantly increased (R²=0.25, p<0.01), especially during the period 1982?1999 (R²=0.25, p<0.01). This trend, however, was stalled since the late 1990s. Furthermore, as for the trend over the period 1999?2010, its magnitude or even the sign of change substantially depended on the choice of the beginning year. This suggests a non-significant trend in China’s grassland growth over this period. The trends of growing season NDVI also showed remarkably spatial-temporal differences. The extensive grassland greening trend that occurred during the earlier study period 1982?1999 appeared a wide-range reversal during the following study period 1999?2010, especially in the arid and semi-arid regions. The condition of hydro-thermal combination was the main factor controlling these growth changes. Correlation analysis between growing season NDVI and climate factors showed that in most parts of grasslands in China, the vegetation growth was rather driven by precipitation than by temperature. While for the grasslands in alpine regions and humid or semi-humid regions, the growing season NDVI correlated closely to temperature, indicating that warming exerted a positive effect on grassland growth in these areas.

Hoped for Possible Selves and Its Relationship with Job Engagement and Burnout of Secondary School Teachers

TANG Xulin,XIA Yunying,GAN Yiqun

2013, 49(2):  329-335. 

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The authors discuss the relationship between hoped for possible selves and teaching behavior (including job engagement and teacher burnout) of secondary school teachers. Basing on the expectancy-value models of motivation, perceived instrumentality and teaching efficacy are chosen as the two variables’ mediators. The questionnaire survey is used to 252 teachers in seven secondary schools and the data is collected by adapted scales for teachers of Hoped for Possible Selves Scale, Perceived Instrumentality Scale, Teaching Efficacy Scale, Job-Burnout Inventory for Middle School Teachers and UWES. The result indicates that perceived instrumentality is a fully mediator between hoped for possible selves and job burnout, but not one between hoped for possible selves and job engagement. Teaching efficacy fully mediates the relationship between hoped for possible selves and job engagement and teaching burnout.

Study on Relationship between Livelihood Capital and Livelihood Strategy of Farming and Grazing Households: A Case of Uxin Banner in Ordos

MENG Jijun,Amrulla,LIU Yang,XIANG Yunyun

2013, 49(2):  321-328. 

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Based on the questionnaire survey and mathematical statistics, quantitative evaluation of the livelihood assets in Uxin Banner was made, revealing the relationship between livelihood assets and livelihood strategies and analyzing the influences of de-farming and anti-grazing policy on the local livelihood. The main research results are as follows. Firstly, pasture area, credit conditions, family income and livestock quantity are important livelihood assets for the local households, while the stocks of social assets and human assets are relatively lower, indicating rich natural resources, adequate financial inventory assets but less ability and quality of people, so that the configuration of livelihood assets couldn’t be optimized properly. Secondly, households possessing rich human, financial and social assets tend to non-agricultural activities, while those with abundant material and natural assets are more willing to agricultural activities. Thirdly, the implementation of de-farming policy leads to the changes in cultivated land amount and planting structure, mainly presenting the phenomenon of “farming for support” and the transfer of agricultural labor forces to non-agricultural activities. And the implementation of anti-gazing policy results in the changes of husbandry management into agricultural management modes, that is a tendency to yard feeding sheep and pigs and developing large-scale and specialty farming, leading to the issue of role-change and needs of vocational training. Fourthly, the implementation of these policies still has several problems, especially in the livelihoods guidance on immigration, protection on basic life, a reasonable determination of subsidies amount and guarantees of follow-up ones, transfer and absorption of surplus labors. Given the above aspects, suggestions on how to improve the local livelihoods strategies while promote the de-farming and anti-grazing policies at the same time have been put forward from the perspective of sustainable livelihood.

Status and Strategy of the Interdisciplinary Research between Social Science and Natural Science at Peking University

HE Jie,ZHOU Hui,XIAO Qun

2013, 49(2):  336-340. 

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By analyzing the research style of Peking University in social science area and natural science area, the authors introduce the status of interdisciplinary research between social science and natural science at Peking University. On the basis of discussing on the measures of promoting interdisciplinary research between social science and natural science implement in international university and China university, the authors give some suggestions on how to promote such researches at Peking University, such as to create atmosphere of interdisciplinary research, to establish an commission of social science and natural science in university level, to set up regulations to promote the collaboration between social science and natural science, to provide students with interdisciplinary courses in social science and natural science, to found communication platform for social research and natural research.

Investigation Study of Quality Management System in Scientific Research in Universities Affiliated to the Ministry of Education

QIU Jianguo,YANG Mohan,LI Jun,ZHANG Jun

2013, 49(2):  341-348. 

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To solve the operating problems of quality management system (QMS) existing in universities, the basic situation of the QMS in universities affiliated to the Ministry of Education were investigated, the system modes and problems existing in the QMS were paid attention, the system changes and the coverage areas were studied. These information provide data support for the study of QMS in scientific research in universities and have important practical significance.