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The financial viability of a rainwater harvesting (RWH) system is highly determined by regional conditions such as rainfall pattern and water prices. Successful implementation of rainwater harvesting systems depends largely on the identification of suitable sites. This paper presents the water saving potential and economic effectiveness of rainwater harvesting systems across eight major cities in China, using a daily water balance model. Results show six to 81 days (or 1.6% to 22.2%) of dependability can be achieved by using a rainwater harvesting system over these cities. The annual water saving efficiency ranges from 10% to 37% and the benefit–cost ratio varies between 0.45 and 1.20 across the studied cities. South China achieves the maximum annual water saving and the highest benefit–cost ratio, while southeast China has the most regular profile of precipitation use. Northwest China was found to be the region with the worst performance, both in yearly water saving and in regularity of rainwater use on a yearly scale. It was also found that the RWH system is not financially feasible in the northeast, southwest and central plains due to the benefit–cost ratios being smaller than 1.0.

Measuring the water content of slopes is essential because the distribution and migration of water within slopes are important factors of landslide instability. In this study, the relationship between the resistivity, volumetric temperature water content and temperature of landslide soil was modelled. The model was validated by indoor landslide model tests and field tests in Baijiabao to investigate the effect of reservoir water levels on the water content of landslide slopes. Test results showed that, as the reservoir levels rose, the water content of the landslide soil increased. Moreover, a good correspondence between the measured results and the inversion results based on the resistivity data was obtained by using the high-density electrical method in combination with the developed model of the relationship between resistivity, volumetric water content and temperature, indicating that the proposed method is reliable and practicable in hydrodynamic landslide monitoring.

Fuelled by the Belt and Road Initiative, Eurasia railway transport has gained rapid traction. However, China Railway Express is in the development period, information about China Railway Express lines is in chaos, and it is difficult to appraise the market situation. This paper focuses on providing an approach to estimate the market share of every China Railway Express line. In this paper, the crawled data from the website are applied to estimate the customer demands for China Railway Express services in different areas of China. The government subsidy is a factor that cannot be ignored, but its level is unclear. Thus, a dummy regression model was established to estimate the subsidy. The regression result is in line with the data released by the Guangdong Provincial Government in 2017. To identify customers’ preferred choices for particular lines, a multi-objective optimization model has been built. With the crawled demands data and this optimization model, the current and future market share of China Railway Express can be assessed. If the subsidy is cancelled, some China Railway Express lines will lose their market, and only three lines have a bright future.

The E1A signal of Galileo system provides high-precision location information service for authorized users. The confidentiality of codes and the auto-correlation multi-peaks of high-order Binary Offset Carrier lead to the lack of relevant research on the quality assessment of E1A signal in the real environment. In this paper, two kinds of high-order BOC tracking algorithms including Bump-Jump and Double Estimator (DET) Technical are studied, then their principles how to eliminate the correlation curve multi-peaks are introduced and compared about advantages and disadvantages. Based on DET, the E1A tracking loop is initialized by using the E1B signal’s carrier information, and then the spreading code modulated message symbol is accurately recovered by waveform-matching method, so the tracking problem of the E1A actual signal is solved. Based on the tracking information of E1A signal, we perform the evaluation of S-Curve Bias (SCB) and correlation loss, and compared those with E1B signal. The results show that the E1A signal correlation loss is greater than the E1B signal, and within 0.15 chip correlator spacing, both SCB are within 0.1 ns. The results have verified the effectiveness of the assessment method of E1A signal quality, as an important reference for improving signal analysis and assessment of GNSS.

BACKGROUND The small brown planthopper (Laodelphax striatellus) is a widespread insect pest of rice in East Asia. Previous studies have shown the long-distance migrations undertaken by L. striatellus, but have not provided molecular evidence to support this. RESULTS Long-distance immigration has occurred in the north-east coastal rice-growing region of China. Using the specific-locus amplified fragment sequencing technique, sequence data for 2.7 Gb of an abruptly increased population and 13 L. striatellus local populations from a range of regions in China that have serious rice stripe disease were obtained. A total of 2572 single nucleotide polymorphisms (SNPs) and 37 indels were detected, and the genotypes of many polymorphism sites were heterozygous in every sample, which indicated that there were rich genetic differences among the populations, and that the migration of insect pests accelerated the gene flow and increased the heterozygosity of L. striatellus populations. The genetic distance and the polymorphism markers among different populations showed that the abruptly increased population in Liaoning Province is close to several populations from Jiangsu Province and Shandong Province. CONCLUSION The vector that caused rice stripe disease in the north-east of China was an immigrant population; however, the population may be formed from several groups from different areas, such as Jiangsu and Shandong provinces. © 2015 Society of Chemical Industry

Inter-satellite link technology is one of hot issues in current satellite navigation field and construction of inter-satellite link system cannot be completed without the cooperation and supports of ground anchor stations. In this paper, with respect to time synchronization issue which is of great importance in the construction of anchor stations for inter-satellite link, key technological issues such as time system design for anchor station, method of synchronization with standard time, clock error of anchor station and the determination of its precision have been deeply discussed and studied. On the base of relevant studies, a complete design method and solution of time synchronization system for anchor station has been proposed herein, thereby offering solution ideas and technological supports for resolving key problems encountered during the construction of anchor stations for inter-satellite link in China. The anchor station time system proposed in this paper can better ensure the time difference between ground station and BDT is less than 1us and the time synchronization precision of anchor station is less than 5ns, thereby guaranteeing the reliability of anchor station acting as Pseudolite being connected to inter-satellite link while offering further reference for subsequent testings and development of inter-satellite link.

Narrowband blanket jamming is common in satellite navigation systems. To suppress narrowband jamming, this paper proposes an adaptive LMS filtering algorithm in the frequency domain by updating partial weight coefficients. Firstly this paper introduces the model and the implementation means of the algorithm, then performs contrastive analysis on the computational complexity and the convergence speed of the algorithm, and finally performs simulation on the algorithm and bit error rate performances of signals pre and post jamming suppression. Theoretical analysis and simulation results show that the partial weight coefficient updated adaptive LMS filtering algorithm is capable of narrowband jamming suppression, with the anti-jamming capability of satellite navigation signals enhanced. The simulation results show that the error rate of our proposed algorithm is better than that of the conventional frequency domain LMS algorithm. The error rates of two algorithms differ by more than an order of magnitude when the SNR is −21dB.

Since the overall distribution of users in the sea area is sparse, it will appear densely in a local angle domain. Specifically, the 3D massive MIMO antenna system are established, which are with the ability to distinguish users in the same horizontal direction as well as vertical direction. According to this, a joint user scheduling and beam selection scheme based on the automatic identification system (AIS) is proposed to solve the problems that of the interference cancellation for the users in the angle domain. In particular, the proposed scheme divides the beam according to the users' location information. Furthermore, we select the user with the highest priority in the beam to form a set of the users in serving, in the meanwhile, the greedy algorithm is used to schedule the user combination to achieve the greatest sum rate. By means of the numerical results, it is shown that the proposed scheme can be used to schedule and serve users in the case of crowded angle domain, and the scheme can obtain near-optimal sum rate.

Sorghum of the family Peaceae (Sorghum bicolor (L) Moench) is an important crop grown worldwide. Sorghum head smut (Sporisorium reilianum(Kuhn)Langdon & Fullerton) is one of major diseases in sorghum production. That are reviewed from the following several aspects of the problem such as the incidence, hazards and physiological race variations of sorghum head smut, the genetic Traits and gene mapping of sorghum resistance to head smut and the research progress on sorghum resistance mechanism to sporisorium reiliana. It is summarized that fine mapping and cloning for sorghum genetic resistance to head smut not only help to employ molecular markers to improve resistance breeding efficiency, but also prove favorable to immune molecular mechanism study on head smut.

A novel R gene was mapped to a locus on chromosome 11 from 30.42 to 30.85 Mb, which was proven to be efficient in the improvement of rice blast resistance. Rice blast is a devastating fungal disease worldwide. The use of blast resistance (R) genes is the most important approach to control the disease in rice breeding. In the present study, we finely mapped a novel resistance gene Pi65(t), conferring a broad-spectrum resistance to the fungus Magnaporthe oryzae, using bulked segregant analysis in combination with next-generation sequencing technology. Segregation in a doubled haploid (DH) population and a BC1F2 population suggested that resistance to blast in Gangyu129 was likely conferred by a single dominant gene, designated Pi65(t); it was located on chromosome 11 from 30.20 to 31.20 Mb using next-generation sequencing. After screening recombinants with newly developed molecular markers, the region was narrowed down to 0.43 Mb, flanked by SNP-2 and SNP-8 at the physical location from 30.42 to 30.85 Mb based on the Nipponbare reference database in build 5. Using the software QTL IciMapping, Pi65(t) was further mapped to a locus between InDel-1 and SNP-4 with genetic distances of 0.11 and 0.98 cM, respectively. Within this region, 4 predicted R genes were found with nucleotide binding site and leucine-rich repeat (NBS-LRR) domains. We developed molecular markers to genotype 305 DH lines and found that InDel-1 was closely linked with Pi65(t). Using InDel-1, a new rice variety Chuangxin1 containing Pi65(t) was developed, and it is highly resistant to rice blast and produces a high yield in Liaoning province of China. This indicated that Pi65(t) could play a key role in the improvement of rice blast resistance.

The method of common-view is characterized by higher precision, good convenience in use, and cheap instrument. A new time synchronous method for multiple users system by common-view technology is presented based on the GEO Positioning System (GEOPS). And the GEOPS common-view theory is studied for which is different from the other GNSS system. This paper introduces the working process and the time service pattern of the GEOPS. In the GEOPS, the pseudo- range found by the receiver through testing is actually the measurement of the whole link from the main control station and through the satellite to the receiver. Due to the different distances between the main control station and each satellite, this measurement has to be done using the upload delay correction by the main control station. The upload delay adopts a polynomial model and the polynomial parameters are demodulated from the navigation message to calculate the delay correction value during the adjustment. In accordance with these characteristics of GEOPS, we propose the GEOPS common-view theory. The format parameters of GEOPS common-view and data calculating method are presented. The time synchronization system, the error analysis and the applied plan of GEOPS common-view technology are introduced. Index Terms-GEOPS; multipel users system; time synchronization; common-view

Nowadays, multipath remains as an unsolved key problem for high precision applications, such as satellite navigation and position. Because GNSS broadcasted signals are subject to reflection and diffraction, just like any other type of electromagnetic waves, multipath is caused by the reception of direct signal together with the reflected or/and diffracted signals at the same time. Multipath will result in errors in pseudorange measurement and carrier phase measurement, and thus affect the positioning accuracy. To verify the effects of multipath propagation on positioning performance, the principle of multipath is introduced in the beginning of this paper. Then based on a simulation platform and mathematical verifying model, the multipath performance and its impact on positioning performance of received GNSS signal is comprehensively demonstrated from different aspects, such as pseudorange multipath error, waveform shape, modulation error, and correlation characteristics and so on. Results indicate the degradation of positioning performance when multipath signals were present, causing position error with several meters to tens of meters. Those results and data we have obtained from this paper could be used as a valuable reference for BDS future signal design and system constructions.

With the development of GNSS, the design and optimum selection of the ranging code is of significant importance for navigation system design. This paper describes the generation of the Weil code based on the design of ranging code. And then in order to select ranging codes of better performance, the paper describes a new optimum selection method in detail. This method is a combination of code selection method which is based on MFL and performance analysis method which is based on the peaks of correlation. And the performance of the selected Weil codes is analyzed by the methods based on peaks of correlation and Welch bound. The results demonstrate that the optimum selection method is of good rationality and of great importance for the design of navigation signals.

Since the research on compatibility is becoming a worldwide “hot spot”, decision has been made to improve the anti-jamming performance between satellite systems. Nowadays, primarily been driven, amongst other motivations, by the desire to ameliorate the compatibility performance of GNSS, speculation has continued on the possibility of further optimization. Of special interests is the inter-system interference that one satellite navigation system will suffer due to another satellite navigation system. This paper reports our recent studies in seeking methods for analyzing the inter-system interference.

In this paper, a control method for making automated distributed management decisions is studied. And the consequences of externalized management on services and the system architecture is studied also. A simulation is performed to evaluate the suggested control method. The simulation results show that the automated manager needs 1) a system view classifying the current system state based on local knowledge, 2) a learner providing an optimal decision policy, and 3) an adaptive service architecture with abilities to compensate disturbance.

Ultra wideband (UWB) wireless communication technology has been regarded as a very important way of indoor short distance, high speed transition at present. In this paper the system structures and working principles of indoor positioning using UWB are introduced. The basic location principles and realization ways based on TDOA (Time-Difference-Of Arrival) are discussed and a new method to estimate the value of TDOA is proposed. In the indoor positioning system, the content being transmitted are simple, the system complexity is low, and it is prone to link with other outdoor positioning system such as GPS to realize accurate positioning.

In this paper, based on Anylogic6.0 simulation software, some simulation models of queuing systems with different queuing disciplines are established, including First Come First Service, Last Come First Service and Random Service. Compared with the theoretical values, the accuracy of the experiment data is verified. Finally, with Comparative Analysis of experiment data, we show that under a special condition, the difference of the performance of the queuing systems with different queuing disciplines is limited.

The Intra-Orbit-Links(IOL), which play the key role during the satellite communication, is introduced. The geometrical model of IOL in the Treble-Layer Satellite Network(TLSN) is constructed. The IOL inside different kinds of TLSN is simulated, that not only the advice of research on More-Layer Satellite Network is given, but the conclusion that a MEO-GEO-IGSO TLSN is batter than kinds of constellation construction is also proved.

Precise indoor positioning is becoming increasingly important in commercial, military and public service applications for tracking people and asset. Ultra Wide Band (UWB) can provide high accuracy position with strong anti-jamming and low power consumption. It is very suitable for indoor positioning application. This paper will put emphasis on indoor positioning system based on UWB.Analysis and implementation of indoor positioning systems based on UWB require an accurate channel model to determine that can be achieved, to design efficient modulation and coding schemes, and to develop associated signal-processing algorithms and effective method of hardware implementation. The structure of indoor positioning system based on UWB is introduced and some system parameters and modulation are determined in this paper. After description the structure of receiver and transmitter of system, a detailed analysis of UWB indoor channel characteristics is given and some algorithms of channel estimation and equalization are discussed in this paper. Some channel estimation techniques based on preamble training sequences and pilot sub-carriers are researched in depth. Further more, the linear estimations of least square (LS) and minimum mean square error (MMSE) are analyzed and compared under different UWB channel conditions and then suitable algorithm for this system is selected. Based on this selection, a scheme for FPGA implementation is proposed, and then some most significant modules for channel estimation and equalization has validated with Xilinx Virtex IV FPGA. It has been shown by some modelsim simulations that this channel estimation and equalization approach has some merits, such as simple implementation and less consumption of resource. It can meet the requirement of system design and some good performances can be achieved.

The key technology in multi-band orthogonal frequency division multiplexing ultra wide band (MB-OFDM-UWB) system is inverse fast Fourier transforms (IFFT) which is used to implement OFDM modulation. However, the realization of multiplier with field programmable gate array (FPGA) in IFFT needs a large number of resources. This paper describes the implementations of IFFT based on coordinate rotation digital computer (CORDIC) algorithm. The whole structure of IFFT using CORDIC algorithm is shown in the form of double-rams architecture which is implemented based on FPGA with the software tools of ISE foundation and modelsim. The simulation results show that it's convenient to realize IFFT with a high speed of more than 270 MHz with fewer resources than by using multipliers of FPGA chip directly and that the implementated IFFT module can produce an output of right data within an acceptable error range.

Multi-band orthogonal frequency division multiplexing (MB-OFDM) is a suitable solution to implementation of high speed data transmission in ultra wideband (UWB) spectrum by dividing the spectrum available into multiple bands. MB-OFDM system structure and transmitted signal is introduced in this paper. Channel models are fundamental to the study and design of communication systems. A survey on indoor wireless channels for UWB radio is given and the IEEE 802.15.3a model for UWB channel models is introduced in detail in this paper. The least square (LS ) channel estimation based on comb type pilot and linearity insertion are described and some simulation results is given in this paper. The simulation results have shown that this method has good performance, can meet the demand of MB-OFDM system with high estimation precision, strong resistance to ICI and easy realization.

The convolutional code cell is an essential part in a transmitter of multi-band orthogonal frequency division multiplexing ultra wide band (MB-OFDM-UWB) system introduced in this paper as a kind of useful channel coding to offer more protection against all kinds of channel noise under indoor channel environments. In this paper, some kinds of convolutional codes for MB-OFDM-UWB system are designed. And then, two different structures for the implementations of convolutional codes are presented respectively. The two different structures of convolutional codes are implemented based on field programmable gate array (FPGA) chip with the software tools of ISE foundation and modelsim. The simulation results show that the performance of parallel structure is better than that of pipe line structure and that it's convenient to implement based on a mother code rate of 1/3 the punctured convolutional code with different code rates that are needed by different modules of the OFDM-UWB system. The implementation of convolutional code technique with FPGA chip can be fit to all kinds of applications of OFDM-UWB system with no transformations.

Multi-Band Orthogonal Frequency Division Multiplexing (MB-OFDM) is a suitable solution to implementation of high speed data transmission in ultra wideband spectrum by dividing the spectrum available into multiple bands. The baseband of transmitter is one of the most important parts in MB-OFDM system. The structure of MB-OFDM system transmitter is introduced in this paper and the design of transmitter baseband based on FPGA is described in detail. The design has been validated with Xilinx Virtex II FPGA. The results show that all modules designed has achieved the expected purpose both in precision and resource, with simplicity and high efficiency, and can meet the demand of MB-OFDM systems.

System integrated clock (SIC) plays an important role in implementing the high-accuracy constellation automatic time synchronization and information exchange. In the establishment of SIC, error and noise are unavoidably introduced. In the paper, various error sources in the process are analyzed at first, and then an error-reduction method under the model of two-way plus common view time comparison is put forward and analyzed. Theory research and simulation experiment show that the constellation time synchronization error is below 10 seconds.