Capacity model of on-rampmerging section of urban expressway

To establish the empirical capacity model of an on- ramp merging section, the Erlang distribution is first selected to define the time headway distribution, and then the gap acceptance theory is applied to develop the basic capacity model of the on-ramp merging section. Since not all the time headways on the shoulder lane can be made full use of by on- ramp vehicles, a modified capacity model is developed, which takes the usage probability of time headway into consideration. Then, a model of capacity discount coefficient ~： is developed. Finally, based on the modified capacity model and the model of capacity discount coefficient, an empirical merge capacity model which contains the shoulder lane volume, critical gap, and the distance from nose to merging point, is constructed. Results show that, compared with other models, the proposed model is more reasonable since it takes merging section geometry into consideration, and it is easy to apply. The merge capacity varies with the shoulder lane volume, the critical gap, the distance between the nose and the merging point, and the design velocity of the shoulder lane and ramp.

Influence of varied drought types on soil conservation service within the framework of climate change:insights from the Jinghe River Basin,China

Severe soil erosion and drought are the two main factors affecting the ecological security of the Loess Plateau,China.Investigating the influence of drought on soil conservation service is of great importance to regional environmental protection and sustainable development.However,there is little research on the coupling relationship between them.In this study,focusing on the Jinghe River Basin,China as a case study,we conducted a quantitative evaluation on meteorological,hydrological,and agricultural droughts(represented by the Standardized Precipitation Index(SPI),Standardized Runoff Index(SRI),and Standardized Soil Moisture Index(SSMI),respectively)using the Variable Infiltration Capacity(VIC)model,and quantified the soil conservation service using the Revised Universal Soil Loss Equation(RUSLE)in the historical period(2000-2019)and future period(2026-2060)under two Representative Concentration Pathways(RCPs)(RCP4.5 and RCP8.5).We further examined the influence of the three types of drought on soil conservation service at annual and seasonal scales.The NASA Earth Exchange Global Daily Downscaled Projections(NEX-GDDP)dataset was used to predict and model the hydrometeorological elements in the future period under the RCP4.5 and RCP8.5 scenarios.The results showed that in the historical period,annual-scale meteorological drought exhibited the highest intensity,while seasonal-scale drought was generally weakest in autumn and most severe in summer.Drought intensity of all three types of drought will increase over the next 40 years,with a greater increase under the RCP4.5 scenario than under the RCP8.5 scenario.Furthermore,the intra-annual variation in the drought intensity of the three types of drought becomes smaller under the two future scenarios relative to the historical period(2000-2019).Soil conservation service exhibits a distribution pattern characterized by high levels in the southwest and southeast and lower levels in the north,and this pattern has remained consistent both in the historical and future periods.Over the past 20 years,the intra-annual variation indicated peak soil conservation service in summer and lowest level in winter;the total soil conservation of the Jinghe River Basin displayed an upward trend,with the total soil conservation in 2019 being 1.14 times higher than that in 2000.The most substantial impact on soil conservation service arises from annual-scale meteorological drought,which remains consistent both in the historical and future periods.Additionally,at the seasonal scale,meteorological drought exerts the highest influence on soil conservation service in winter and autumn,particularly under the RCP4.5 and RCP8.5 scenarios.Compared to the historical period,the soil conservation service in the Jinghe River Basin will be significantly more affected by drought in the future period in terms of both the affected area and the magnitude of impact.This study conducted beneficial attempts to evaluate and predict the dynamic characteristics of watershed drought and soil conservation service,as well as the response of soil conservation service to different types of drought.Clarifying the interrelationship between the two is the foundation for achieving sustainable development in a relatively arid and severely eroded area such as the Jinghe River Basin.

Empirical Research on Carrying Capacity of Human Settlement System in Dalian City, Liaoning Province, China

Using the theories of population carrying capacity and ecological elasticity in other fields for reference, the connotation of regional human settlement system was defined from the viewpoint of the complex relationship among the factors such as regional population, resources, environment and economic and social development in the context of China′s rapid urbanization. Then the concept and characterization methods of the regional human settlement carrying capacity were proposed by means of population scale. Furthermore, a model of carrying capacity-pressure-state-response(CPSR) on regional human settlement system was established by referencing pressure-state-response(PSR) model, and the Catastrophe Theory was introduced to determine the corresponding standards of multi-criteria programming and evaluation. Taking Dalian City, Liaoning Province, China as an example, an empirical analysis on evaluation of human settlement system from 2000 to 2012 was carried out. The results showed that the carrying capacity of human settlement system in Dalian was fluctuating between 9.6 × 106 to 10 × 106 persons with a quantitative stage of the dynamic regulation. During the research period the load index of human settlement system in Dalian dropped from 0.96 to 0.84 with a lower pressure of human settlement system than the national average level. And the emergency response grades of human settlement system in Dalian were kept in grade Ⅱ(orange warning) or grade Ⅲ(yellow warning). Human settlement system of Dalian was in slight security state as a whole, but the load had a tendency of increase in recent years. The related departments should pay close attention to regional human settlement system and take active measures to improve human settlement by both intensity control and total quantity control. By comparison, analysis and discussion, it was considered that the results were basically accordded with the current situations of human settlement in Dalian, and the evaluation results were more reliable, visualized and easily applied in practice. Therefore, the above-mentioned concepts, characterization and evaluation methods of the regional human settlement system and carrying capacity could provide a new thought and method for quantitative evaluation of human settlement.

Transmission Capacity Analysis for Linear VANET under Physical Model

In this study, the transmission capacity of VANETs in a highway scenario is analysed on the basis of a 1D line model and the carrier sense multiple access with collision avoidance(CSMA/CA) protocol. We describe the CSMA/CA protocol used in IEEE802.11 p from the perspective of the geometric relationship amongst simultaneous transmitters. The desired channel and interfering channels are assumed to experience the same amount of path-loss and Rayleigh fading. On the basis of the proposed model, we analyse the attempted transmission probability of each road segment and the maximum intensity of active transmitters, including their theoretical values. Then, we employ the physical model to obtain the outage probability and derive the upper bound of the transmission capacity of a VANET, which is defined as the average spatial density of successful transmissions in the network. Simulation results indicate that the theoretical value offers a good bound on network capacity.

Tangents on TV： The Tangential Relationship of Narrative and Educational Content in Children＇s Television Through the Capacity Model

Previous studies have shown that children learn from educational television; however, these studies have not explored how closely the educational content of the program is integrated to the narrative. The following study uses a systematic content analysis of 100 top-rated U.S. children＇s television programs to explore the tangential relationship （i.e., distance） of narrative and educational content through the lens of the capacity model--which is built upon three basic components： narrative content, educational content, and the distance between them. Programs were analyzed for distance by examining lesson clarity and integration, show type, target audience age, and station type. One-way ANOVAs indicates significant differences between the means of these variables. Programs targeting younger children presented educational content that was closely integrated into the plotline of the program and helped further the story. However, as the target audience aged, the educational content became more tangential to the narrative content and was less tied to the plotline of the program.

Capacity Analysis for Dynamic Space Networks

To evaluate transmission rate of highly dynamic space networks,a new method for studying space network capacity is proposed in this paper. Using graph theory,network capacity is defined as the maximum amount of flows ground stations can receive per unit time. Combined with a hybrid constellation model,network capacity is calculated and further analyzed for practical cases. Simulation results show that network capacity will increase to different extents as link capacity,minimum ground elevation constraint and satellite onboard processing capability change. Considering the efficiency and reliability of communication networks,how to scientifically design satellite networks is also discussed.

Orbital electronic heat capacity of hydrogenated monolayer and bilayer graphene

The tight-binding Harrison model and Green＇s function approach have been utilized in order to investigate the contribution of hybridized orbitals in the electronic density of states（DOS） and electronic heat capacity（EHC） for four hydrogenated structures, including monolayer chair-like, table-like, bilayer AA- and finally AB-stacked graphene. After hydrogenation, monolayer graphene and bilayer graphene are behave as semiconducting systems owning a wide direct band gap and this means that all orbitals have several states around the Fermi level. The energy gap in DOS and Schottky anomaly in EHC curves of these structures are compared together illustrating the maximum and minimum band gaps are appear for monolayer chair-like and bilayer AA-stacked graphane, respectively. In spite of these, our findings show that the maximum and minimum values of Schottky anomaly appear for hydrogenated bilayer AA-stacked and monolayer table-like configurations, respectively.

Investigations of methane adsorption characteristics on marine-continental transitional shales and gas storage capacity models considering pore evolution

Methane adsorption is a critical assessment of the gas storage capacity(GSC)of shales with geological conditions.Although the related research of marine shales has been well-illustrated,the methane adsorption of marine-continental transitional(MCT)shales is still ambiguous.In this study,a method of combining experimental data with analytical models was used to investigate the methane adsorption characteristics and GSC of MCT shales collected from the Qinshui Basin,China.The Ono-Kondo model was used to fit the adsorption data to obtain the adsorption parameters.Subsequently,the geological model of GSC based on pore evolution was constructed using a representative shale sample with a total organic carbon(TOC)content of 1.71%,and the effects of reservoir pressure coefficient and water saturation on GSC were explored.In experimental results,compared to the composition of the MCT shale,the pore structure dominates the methane adsorption,and meanwhile,the maturity mainly governs the pore structure.Besides,maturity in the middle-eastern region of the Qinshui Basin shows a strong positive correlation with burial depth.The two parameters,micropore pore volume and non-micropore surface area,induce a good fit for the adsorption capacity data of the shale.In simulation results,the depth,pressure coefficient,and water saturation of the shale all affect the GSC.It demonstrates a promising shale gas potential of the MCT shale in a deeper block,especially with low water saturation.Specifically,the economic feasibility of shale gas could be a major consideration for the shale with a depth of<800 m and/or water saturation>60%in the Yushe-Wuxiang area.This study provides a valuable reference for the reservoir evaluation and favorable block search of MCT shale gas.

Power allocation and mode selection methods for cooperative communication in the rectangular tunnel

For the multipath fading on electromagnetic waves of wireless communication in the confined areas,the rectangular tunnel cooperative communication system was established based on the multimode channel model and the channel capacity formula derivation was obtained.On the optimal criterion of the channel capacity,the power allocation methods of both amplifying and forwarding(AF) and decoding and forwarding(DF) cooperative communication systems were proposed in the limitation of the total power to maximize the channel capacity.The mode selection methods of single input single output(SISO) and single input multiple output(SIMO) models in the rectangular tunnel,through which the higher channel capacity can be obtained,were put forward as well.The theoretical analysis and simulation comparison show that,channel capacity of the wireless communication system in the rectangular tunnel can be effectively enhanced through the cooperative technology;channel capacity of the rectangular tunnel under complicated conditions is maximized through the proposed power allocation methods,and the optimal cooperative mode of the channel capacity can be chosen according to the cooperative mode selection methods given in the paper.

Multiple time scales of fluvial processes—theory and applications

Fluvial processes comprise water flow,sediment transport and bed evolution,which normally feature distinct time scales.The time scales of sediment transport and bed deformation relative to the flow essentially measure how fast sediment transport adapts to capacity region in line with local flow scenario and the bed deforms in comparison with the flow,which literally dictates if a capacity based and/or decoupled model is justified.This paper synthesizes the recently developed multiscale theory for sediment-laden flows over erodible bed,with bed load and suspended load transport,respectively.It is unravelled that bed load transport can adapt to capacity sufficiently rapidly even under highly unsteady flows and thus a capacity model is mostly applicable,whereas a non-capacity model is critical for suspended sediment because of the lower rate of adaptation to capacity.Physically coupled modelling is critical for fluvial processes characterized by rapid bed variation.Applications are outlined on very active bed load sediment transported by flash floods and landslide dam break floods.

A LIMITED ORDER CAPACITY STOCHASTIC INVENTORY MODEL WITH A FIXED COST FOR ORDER: THE DISCOUNTED CASE

This paper considers a single-item, periodic-review inventory model with linear ordercosts, a convex function representing expected one-period costs, nonegative i.i.d. demandsand a fixed cost for order. Stockouts are backordered. All data are stationary Both finiteand infinite horizon problems are treated.

Capacity drop through reaction times in heterogeneous traffic

The capacity drop forms a major reason why the prevention of congestion is targeted by traffic management, as lower capacities are detrimental to traffic throughput. Various reasons describing the dynamics behind the capacity have been described, however one of these, reaction times, has had less explicit attention when modelling on a macroscopic flow level. In this contribution, a method to include the effect of reaction times for the capacity drop in heterogeneous traffic is proposed. The applied method further overcomes difficulties in including reaction times in a discrete time model through relaxation of the updating process in the discretization. This approach is novel for application in the considered first order approach, which is practise ready, contrary to many other models that propose similar approaches. The combination of the introduced method and the model form a solid development and method to apply the capacity drop based on this causation of the capacity drop. The results of the experiment case showed that the influence of traffic heterogeneity had a limited effect on the severity of the capacity drop, while it did influence the time of congestion onset. The influence of the reaction time on traffic showed greater capacity drop values for greater reaction time settings. The findings showed the method effective and valid, while the model application is also practise ready.

Storage capacity model for cloud download

With the rise and world wide deployment of cloud utilities, the principle of the cloud download is proposed to provide high-quality file content distribution by using dedicated servers as cloud cache to guarantee the data availability and enhance the data transfer rate. As the system scales up to a large population, how to design appropriate storage capacity of cloud cache is a key challenge for cloud download. In this paper, primary elements impacting on storage capacity are explored through deliberating in large-scale commercial cloud download system, i.e. general user usage pattern and available period. And based on statistical analysis of real-world traces, we formulate storage capacity related to these two elements, which is the original contribution different from all previous works. This model gives guidance of potential system policy design. Finally, the effectivity of this model is demonstrated by simulation results compared with empirical data of practical system.

A Method to Estimate the Steganographic Capacity in DCT Domain Based on MCUU Model

In order to estimate maximum steganographic capacity of discrete cosine transform（DCT） domain in JPEG image, this paper presents a method based on the maximize capacity under undetectable model（MCUU）. We analyze the relation between steganographic capacity and affecting factors（image size, steganography operator, loading band, embedding intensity and image complexity）. Then we design a steganography analyzer architecture and a steganographic algorithm which can dynamically increase the steganographic capacity. Compared with other methods of embedding capacity estimation in DCT domain, the proposed methods utilizes general steganalysis methods rather than one specific steganalysis technique and takes five essential factors into account, which improves the commonality and comprehensiveness of capacity estimation, respectively. The experimental results show that steganographic capacity for quantization index modulation（QIM） is almost twice that of spread spectrum（SS） based on MCUU model.

Comprehensive experimental database and analysis of circular concrete-filled double-skin tube stub columns:A review

A concrete-filled double-skin tube(CFDST)is a new type of composite material.Experimental studies have been conducted to investigate the axial compression behavior of CFDST members for approximately 30 years.This paper provides a review of the status of axial compression bearing capacity tests conducted on circular CFDST stub columns as well as a summary of test data for 165 circular CFDST stub columns reported in 22 papers.A relatively complete high-quality test database is established.Based on this database,the main factors affecting the axial compression bearing capacity of the CFDST stub columns are analyzed.The prediction accuracy and robustness of an existing theoretical prediction model,which is a data-driven model,are evaluated,and a numerical simulation of the axial compression bearing capacity of the CFDST stub columns is conducted.In addition,the differences between the basic theory and experimental results of various models are compared,and the possible sources of prediction errors are analyzed.The current model for predicting the axial compression capacity of CFDST stub columns cannot simultaneously satisfy the requirements of high accuracy and confidence,and the stress independency assumption introduced in the test is not valid.The main error source in the theoretical prediction model is the non-simultaneous consideration of the effects of the void ratio and inner steel tube.

Probabilistic Flood Prediction in the Upper Huaihe Catchment Using TIGGE Data

Based on the precipitation and temperature data obtained from THORPEX （The Observing System Research and Predictability Experiment） Interactive Grand Global Ensemble （TIGGE）-China Meteorological Administration （CMA） archiving center and the raingauge data, the three-layer variable infiltration capacity （VIC-3L） land surface model was employed to carry out probabilistic hydrological forecast experiments over the upper Huaihe River catchment from 20 July to 3 August 2008. The results show that the performance of the ensemble probabilistic prediction from each ensemble prediction system （EPS） is better than that of the deterministic prediction. Especially, the 72-h prediction has been improved obviously. The ensemble spread goes widely with increasing lead time and more observed discharge is bracketed in the 5th-99th quantile. The accuracy of river discharge prediction driven by the European Centre （EC）-EPS is higher than that driven by the CMA-EPS and the US National Centers for Environmental Prediction （NCEP）-EPS, and the grand-ensemble prediction is the best for hydrological prediction using the VIC model. With regard to Wangjiaba station, all predictions made with a single EPS are close to the observation between the 25th and 75th quantile. The onset of the flood ascending and the river discharge thresholds are predicted well, and so is the second rising limb. Nevertheless, the flood recession is not well predicted.

Impact of Climate Change on Streamflow in the Xitiaoxi Catchment, Taihu Basin

The impact of climate change on streamflow in the Xitiaoxi catchment is assessed by using VIC （variable infiltration capacity） model coupled with PRECIS （providing regional climate for impacts studies）. Results show that the VIC model is adaptable for the study area. Both deterministic coefficient and NashSuttcliffe efficiency coefficient are greater than 0.75, with a good agreement between observed and simulated discharge. The runoff will increase in the future, especially during flood seasons. The magnitude of floods in the future （2021-2050） under A2 and B2 scenarios will be greater than that during the baseline period （1961-1990）, but it may not exceed that during the 1990s.