Research on Combined Optimization of Intercontinental Intermodal Transport Scheme by Railway Network and Double Difference Model

The development of the commercial multi global navigation satellite system (GNSS) dual (multi)-antenna common-clock receiver that uses time-synchronization technology has brought new opportunities for high-precision GNSS-based attitude determination. In this article, for the first time, we present a performance comparison of global positioning system (GPS) L1/Galileo navigation satellite system (Galileo) E1 attitude determination with a common-clock receiver using four different models, i.e., the loosely combined single-differenced (SD-LC) model, the tightly combined single-differenced (SD-TC) model, the loosely combined double-differenced (DD-LC) model, and the tightly combined double-differenced (DD-TC) model. We first introduce the SD-LC, SD-TC, DD-LC, and DD-TC relative positioning models with GPS L1/Galileo E1 observations from a common-clock receiver. Then, we present a performance comparison of the four models in both single-epoch and multi-epoch modes using static data collected with a Trimble BD992 common-clock receiver in terms of the ambiguity dilution of precision (ADOP), the ambiguity resolution (AR) success and failure rates, and the positioning and attitude determination accuracy. In the case of the single-epoch mode, the experimental results revealed that the results of the single-differenced (SD) models were identical to those of double-differenced (DD) models, i.e., the results of SD-LC and SD-TC models were identical to DD-LC and DD-TC models, respectively. Moreover, compared with the loosely combined model (SD-LC/DD-LC), the tightly combined model (SD-TC/DD-TC) delivered a much higher AR success rate and a lower AR failure rate, especially under a high elevation cutoff angle. The AR success rate increased by approximately 35.1% under a 40° elevation cutoff angle, while the AR failure rate decreased by approximately 4.3%. In the case of the multi-epoch mode, the experimental results confirmed the advantages of the tightly combined model over the loosely combined model as well as the SD model over the DD model. Compared with the DD-LC and SD-LC models, the AR success rates of the DD-TC and SD-TC models were improved by approximately 16.7% and 0.6% under a 45° elevation cutoff angle, respectively. The AR failure rates were reduced by approximately 12.4% and 0.3%, respectively. Moreover, compared with the DD-LC and DD-TC models, the AR success rates of the SD-LC and SD-TC models under a 45° elevation cutoff angle were improved by approximately 24.0% and 7.9%, respectively, and the AR failure rates were reduced by approximately 19.9% and 7.8%, respectively. Meanwhile, compared with the DD model, the SD model delivered comparable yaw accuracy and remarkably better pitch accuracy. The pitch accuracy was improved by approximately 65.2–75.0%.

Freight transport is constantly growing and the forecast is that this trend will continue in the future. The sustainable development of transport requires the development of activities, which yield higher economic and social results while at the same time reduce the negative impact on the environment. In the long term, the sustainable development of transport activities is complex and tied to enormous challenges, difficulties and barriers, related to the development of the technological environment, the social and economic development, the influence of political factors and regulations. One of the central perspectives for the development of the freight transport in Europe is the development of multimodal and intermodal transport. The present chapter reviews some essential issues about the conditions for interaction between the modes of freight transport and the main challenges this kind of transport faces. An overview has been made of the main characteristics of organization and technology in multimodal and intermodal transport, and the related to them commodal and synchro modal transport that have appeared in recent years, as well as the physical internet concept. The application and barriers for modern use of information and communication technologies in multimodal and intermodal transport has been reviewed. An overview of the development of multimodal and intermodal transport in Bulgaria in accordance with the development of international transport corridors that pass through the country is carried out. A mathematical model has been developed on the basis of multicriteria optimization with three criteria: direct costs, time and external costs. The transport scheme is presented as an oriented graph line with each point corresponding to a node and each road, connecting nodes i and j, to an oriented weighted rib (i, j) in the graph. Weight cij is directly connected to the three criteria set. We assume that on each rib transport can be carried out by three modes: waterway, road and rail. If there is no physical connection, the respective weight is assumed to be an infinitely large number. Pareto optimal solutions have been determined under conditions for integer variables and application of a weighting method. To verify the model, a specific task for providing multimodal transport has been solved with the help of Matlab R2017b software and the optimization functions built into the product have been found to be optimal under Pareto solutions, using heuristic approaches for solving a partially integer linear optimization problem.KeywordsMultimodal transportThree-criteria optimizationInternal costRoute and time optimizationFreight and passenger transportation

Railway network delay evolution: A heterogeneous graph neural network approach

An increasing number of reference stations have been established, leading to a sharp increase in the workload of Double-Difference (DD) baseline solutions, which are not appropriate for the integrated processing of denser networks. Correlations among the ambiguities in DD models are complex, and it is difficult to get precise solutions. This paper improves the DD ambiguity resolution performance over a long baseline, using a modified strategy based on an Un-Differenced (UD) and Un-Combined (UC) model. The satellite clocks are estimated as parameters, which are properly constrained by real-time satellite clock products for improving the smoothness of ambiguities. We use data from the Earth Scope Plate Boundary Observatory to examine the presented method in Global Positioning System (GPS) networks. Our method obtained more obviously centralised distributions. The successful fixed rate was 96·4% for the DD baseline solution, and 98·4% for the UD method. The proposed strategy is appropriate for the distributed architecture of extensive systems and avoids a heavy computational burden.

China’s agricultural OFDI has achieved a new promotion of regional opening to the RCEP agricultural field, and the bilateral agricultural trade cooperation has great potential. China’s agricultural OFDI has been steadily increasing in recent years. As significant trade partners for Chinese agricultural products, RCEP countries represent an important region for China’s agricultural OFDI initiatives. However, existing studies have paid little attention to the trade effect and dynamic impact of China’s agricultural OFDI on agricultural products of RCEP countries. Therefore, based on the panel data of agricultural trade between China and RCEP countries from 2004 to 2019, this paper uses the trade gravity model and TVP-VAR model to investigate the time-varying effects of China’s agricultural OFDI on agricultural trade of RCEP countries. The findings are as follows: (1) The impact of China’s agricultural OFDI on bilateral agricultural trade between China and RCEP countries has significant time-varying characteristics, and there are short-, medium-, and long-term positive impacts most of the time. (2) When the bilateral agricultural trade reaches a certain level, the role of China’s agricultural OFDI is limited, but the overall positive and significant impact remains, showing a strong trade effect. (3) The positive impact on China’s agricultural OFDI has a heterogeneous impact on RCEP countries with different income levels and geographical connections, but the overall positive externality effect is significant. The research conclusions expand the research perspective on the trade effect of agricultural OFDI to a certain extent and provide management and policy implications for agricultural enterprises to “move fast” and promote the sustainability of bilateral agricultural trade between China and RCEP countries through government efforts.

This paper represents a new proposed trade model of "Intercountries Trade Force (ITF)" which is inspired by Intermolecular Interaction Forces in chemical sciences, and has potential to compensate for the deficiencies of the gravity trade model proposed by Jan Tinbergen in 1962. The main differences between our new model and the earlier gravity trade theory are (i) there is a time-variant variable called the gravity index (GI) which means that the earlier gravity theory was treated as only a variable in our new proposed model and (ii) our new proposed trade model has a higher chance of adoption in the real trade world rather than the earlier gravity trade model which always needs to be expanded by scholars. In order to empirically test our new proposed trade model, we applied it in an empirical econometric model to analyze the Russian gas export to the EU member states, not explored earlier. Results revealed that our new trade proposed model adjusts with the empirical energy trade pattern.

This article analyzes the current trade situation between China and the five countries of the Eurasian Economic Union. From the perspective of trade scale, the trade between China and Russia accounts for the largest share, followed by the trade between China and Kazakhstan. However, in terms of bilateral trade structure, the trade products are mostly labor-intensive products and primary products, the trade between China and the Eurasian Economic Union is still at a low level. Then, combined with panel data, using the trade gravity model, selecting the GDP, GNI, geographical distance, and borderline of the two trading countries as independent variables to measure the trade potential of China and the five countries of the Eurasian Economic Union. The trade potential of China has not yet been fully tapped, and there is a possibility of further development. KeywordsEurasian economic unionTrade gravity modelTrade potential

This paper aims to investigate the relationship between enterprise digital transformation and “information infrastructure” by analyzing the mechanism of enterprise digital transformation under the new infrastructure, constructing an input-output analysis model and a double difference model, and conducting a parallel trend test on the two models, bringing in the data between enterprise digital transformation and “information infrastructure” on the model, and studying the relationship between the two and the degree of influence. The relationship between the two and the degree of influence is investigated by bringing in the data of “information infrastructure”. The resulting data show that artificial intelligence accounts for 25.4% of digital transformation, followed by IoT at 19.7% and 3D printing at 1.4% of digital transformation. The change in the number of state-owned enterprises and non-state-owned enterprises before and after digital transformation is the largest in the range of 0-50%, with 44.4% change in the number of state-owned enterprises and 31.25% change in the number of non-state-owned enterprises. The research in this paper provides favorable data and analysis to prove that “information infrastructure” drives the digital transformation of enterprises.

The business scale of China's high-speed railroad is increasing, which has brought important impact on the economy of the cities passing along the high-speed railroad. High-speed railroad has faster speed, safer, and stronger ability to transport goods compared with train, which provides a better choice for people's transportation, tourism, etc., and also has a great impact on the economic development of the cities along the route. This paper is based on the Wuhan-Guangzhou high-speed railway along Hunan Province.To ensure accurate empirical results, we specifically choose Hunan Province as the basis for data analysis, as it is the only province in the area and eliminates potential interference from other municipalities. We collect data from 2005 to 2019, specifically from prefectural-level cities and above. The empirical analysis is conducted using the double difference model (DID). An analysis is conducted on the effects of high-speed railroads on the growth rate of GDP, per capita GDP, the total employment at the end of the year, and the urban development along the lines. The findings indicate that high-speed rail has a discernible bias in its economic impact on cities along its route. Specifically, it has a substantial influence on the employment and urbanisation development of these cities. However, it does not have a significant effect on the short-term per capita GDP and its growth rate.

Green financial innovation and digital transformation of new energy enterprises: Evidence from a quasi-natural experiment.

Estimating the impact of wildlife damage compensation policy on farmers’ incomes

Based on the use of trade integration index and gravity model, this paper uses the bilateral goods trade data between China and Australia from 2000 to 2019 to analyze the trade status, trade complementarity and trade potential between China and Australia. The results of the study show that the trade scale, trade complementarity and trade potential between China and Australia are constantly expanding. However, from the perspective of trade balance, China has always been in the position of a deficit country, and the deficit is getting larger and larger, especially in terms of primary products. Judging from the trade integration index, China’s trade integration with Australia generally shows an upward trend, indicating that the trade dependence between China and Australia is gradually increasing. Judging from the results of the trade potential analysis, the trade potential between the two countries has not been fully realized, and there is still much room for improvement in bilateral trade relations.

Reliability of the intermodal transport network under disrupted conditions in the rail freight transport

Aiming at the problem that the traditional inter-system double-difference model is not suitable for non-overlapping signal frequencies, we propose a new inter-system double-difference model with single difference ambiguity estimation, which can be applied for both overlapping and non-overlapping signal frequencies. The single difference ambiguities of all satellites and Differential Inter-System Biases (DISB) are first estimated, and the intra-system double difference ambiguities, which have integer characteristics, are then fixed. After the ambiguities are successfully fixed, high-precision coordinates and DISB can be obtained with a constructed transformation matrix. The model effectively avoids the DISB parameter filtering discontinuity caused by the reference satellite transformation and the low precision of the reference satellite single difference ambiguity calculated with the code. A zero-baseline using multiple types of receivers is selected to verify the stability of the estimated DISB. Three baselines with different lengths are selected to assess the positioning performance of the model. The ionospheric-fixed and ionospheric-float models are used for short and medium-long baselines, respectively. The results show that the Differential Inter-System Code Biases (DISCB) and Differential Inter-System Phase Biases (DISPB) have good stability regardless of the receivers type and the signal frequency used and can be calibrated to enhance the strength of the positioning model. The positioning results with three baselines of different lengths show that the proposed inter-system double-difference model can improve the positioning accuracy by 6–22% compared with the intra-system double-difference model which selects the reference satellite independently for each system. The Time to First Fix (TTFF) of the two medium-long baselines is reduced by 30% and 29%, respectively.

Semarang City is a fascinating city to be studied historically through various aspects, including transportation problems. This paper tries to examine the condition of the transportation network in Semarang at least in the first 30 years of the 20th century. The main problem in this paper is how the condition of the transportation network in Semarang and its impact on Semarang people in the early 20th century. So far, the concern about historical studies in Semarang regarding transportation has always been regarding the railway network centered in this city. However, the railway network is only connecting Semarang with other areas in Central Java and beyond. What about the transportation conditions in the city of Semarang itself?. Of course, the train is not the primary mode if we talk about transportation mode inside the city. In the land transportation network in the big cities in the Dutch East Indies at the end of the 19th century, the mode of transportation using animal power played a huge role. However, changes began to occur when modern transportation modes, such as bicycles, motorbikes, cars, and trams, entered the Dutch East Indies, including Semarang City, at the beginning of the 20th century. The significant impact that occurs is that this mode of transportation provides a new network pattern in transportation, especially the land transportation network in Semarang. This study uses the historical method, which consists of four stages: heuristics, source criticism, interpretation, and historiography. The results of this study indicate that there are complex dynamics in the development of land transportation in Semarang, besides that technology plays an essential role in this development.