EFFECT OF BLASTING ON THE STABILITY OF LINING DURING EXCAVATION OF NEW TUNNEL NEAR THE EXISTING TUNNEL

In recent years, experimental and numerical researches on the effect of blasting pressure on the stability of existing tunnels was widely obtained. However, the effect of the blasting pressure during excavation a new tunnel or expansion old tunnels on an existing tunnel has disadvantages and still unclear. Some researches were carried out to study the relationship of the observed Peak Particle Velocity (PPV) on the lining areas along the existing tunnel direction, due to either the lack of in situ test data or the difficulty in conducting field tests, particularly for tunnels that are usually old and vulnerable after several decades of service. This paper introduces using numerical methods with the field data investigations on the effect of the blasting in a new tunnel on the surrounding rock mass and on the existing tunnel. The research results show that not only predicting the tunnel lining damage zone under the impact of blast loads but also determination peak maximum of explosion at the same time at the surface of tunnel working

Improving Traffic Efficiency in a Road Network by Adopting Decentralised Multi-Agent Reinforcement Learning and Smart Navigation

In the future, mixed traffic flow will consist of human-driven vehicles (HDVs) and connected autonomous vehicles (CAVs). Effective traffic management is a global challenge, especially in urban areas with many intersections. Much research has focused on solving this problem to increase intersection network performance. Reinforcement learning (RL) is a new approach to optimising traffic signal lights that overcomes the disadvantages of traditional methods. In this paper, we propose an integrated approach that combines the multi-agent advantage actor-critic (MA-A2C) and smart navigation (SN) to solve the congestion problem in a road network under mixed traffic conditions. The A2C algorithm combines the advantages of value-based and policy-based methods to stabilise the training by reducing the variance. It also overcomes the limitations of centralised and independent MARL. In addition, the SN technique reroutes traffic load to alternate paths to avoid congestion at intersections. To evaluate the robustness of our approach, we compare our model against independent-A2C (I-A2C) and max pressure (MP). These results show that our proposed approach performs more efficiently than others regarding average waiting time, speed and queue length. In addition, the simulation results also suggest that the model is effective as the CAV penetration rate is greater than 20%

Eruptive-volcanic-basalt structures in the Truong Sa-Spratly Islands and adjacent areas from interpreting gravity and magnetic data

In the Spratly Islands (Truong Sa Islands) and adjacent areas, volcanic activities are quite strong after the sea-floor spreading in the Cenozoic Era. However, it is difficult to define their ranges and spatial locations. Based on the different characteristic between eruptive volcanic basalt and sedimentary rocks near the surface, it can be said that, the blocks which are higher density and magnetization than those surroundings could be identified as eruptive volcanic basalt. This paper presents the methods of reduction to the magnetic equator in low latitudes to bring out a better correlation between magnetic anomalies and their causing-sources; High-frequency filtering is to separate gravity and magnetic anomalies as well as information about the volcanic basalts in the upper part of the Earth's crust; 3D total gradient is to define the spatial location of high density and magnetic bodies. The potential structures of eruptive volcanic basalt are predictively determined by multi-dimensional correlation analysis between high-frequency gravity and magnetic anomalies with weighted total gradient 3D. The results from the above-mentioned methods have shown that the distribution of the eruptive volcanic basalt mainly concentrates along the Spratly Island’s seafloor-spreading axis, transitional crust, Manila trench and some large fault zones. These results are improved by available  seismic data in the study area.References Baranov, V., 1957. A new method for interpretation of aeromagnetic maps: Pseudo-gravimetric anomalies: Geophysics, 22, 359-383. Bhattacharyya, B. K., 1966. Continuous spectrum of the total magnetic field anomaly due to a rectangular prismatic body. Geophysics, 31, 197-212. Bracewell, R., 1999. The Fourier transform and its applications (3nd edition): McGraw-Hill. 496p. Bui Cong Que, Tran Tuan Dung, 2008. Study of crustal structure and Geodynamics in the East Vietnam Sea and adjacent areas. Vietnam Journal of Earth Sciences, 30(4), 481-490. Dang Van Bat, Do Dinh Tat, Mai Thanh Tan, 1994. Characteristics of  lithology and fossils of the Oligocene eruption.  Vietnam Journal of Earth Sciences, 16(2), 59- 66. Hanoi. Flower M.F.J., Zhang M., Chen C-Y., Tu K., Xie G., 1992. Magmatism in the South China Basin, 2. Post-spreading Quaternary basalts from Hainan Island, south China. Chem. Geol., 97, 65-87. Ian N. MacLeod, Keith Jones, Ting Fan Dai, 1993. 3-D Analytic Signal in the Interpretation of Total Magnetic Field Data at Low Magnetic Latitudes. Exploration Geophysics, 24, 679-688. Karoly I. K, 1990. Transfer properties of the reduction of magnetic anomalies to the pole and to the equator. Geophysics. 55(9), 1141-1147. Le Huy Minh, Luu Viet Hung, Vo Thanh Son, 2003. Reduction to the pole at low latitude and interpretation of the magnetic anomaly map of Vietnam. Vietnam Journal of Earth Sciences, 24(2), 164-174. Lee T-Y., Lo C-H., Chung S-L., Chen C-Y., Wang P-L., Lin W-P., Hoang N., Cung T.C., Nguyen T.Y., 1998. 40Ar/39Ar dating result of Neogene basalts in Vietnam and its tectonic implication. In: M.F.J. Flower et al (Eds.). Mantle Dynamics and Plate Interactions in East Asia. Geodynamics Ser., 27, 317-330. Amer. Geol. Union. Leu, L.-K., 1981. Use of reduction-to-equator process for magnetic data interpretation: Presented at the 51st Ann. Internat. Mtg., Sot. Exnl. Geonhv.: Geophysics, 47. Li S-L., Meng X-H., Guo L-H., Yao C-L., Chen Z-X., Li H-Q., 2011. Gravity and magnetic anomalies field characteristics of the East Vietnam Sea and its application for interpretation of igneous rocks, Applied geophysics, 7(4), 295-305. Li Y., D. W. Oldenburg, 2001. Stable reduction to the pole at the magnetic equator, Geophysics, 66, 571-578. MacLeod, I.N., K. Jones and T.F. Dai, 1993. 3-D analytic signal in the interpretation of total magnetic field data at low magnetic latitudes. Exploration Geophysics, 24(4), 679-688. McElhinny, M.W., 1973. Palaeomagnetism and Plate Tectonics, Cambridge, London, 356pp. Chapter 1 presents an introduction to the geomagnetic field. Nabighian MN, 1984. Toward a three-dimensional automatic interpretation of potential field data via generalized Hilbert transforms: Fundamental relations. Geophysics, 49, 780-786. Nguyen Hoang, Phan Trong Trinh, 2009. Characteristics of lithological and geochemical of Neogene - Quaternary volcanic rocks and mantle dynamics in the East Vietnam Sea and adjacent. Journal of Geology, 312. Pham Tich Xuan, Nguyen Trong Yem, 1999. Volcanic activities in late Cenozoic in Vietnam. Vietnam Journal of Earth Sciences, 12(2), 128-135. Phillips, J. D., 1997. Potential-Field Geophysical Software for the PC, version 2.2: USGS open-File Report , 97-725. Roest, W.R., J. Verhoef and M. Pilkington, 1992. Magnetic interpretation using the 3-D analytic signal: Geophysics, 57(1), 116-125. Sandwell, D. T., Garcia E., Soofi K., Wessel P., and Smith W. H. F, 2013. Towards 1 mGal Global Marine Gravity from CryoSat-­2, Envisat, and Jason-1, The Leading Edge, 32(8), 892-899. doi: 10.1190/tle32080892.1. Spector A and Grant FS, 1970. Statistical models for interpreting Aeromagnetic data. Geophys, 35(2), 293-302. Sudhir Jain, 1988. Total magnetic field reduction - The pole or equator? A model study, Canadian journal of exploration in geophysics, 24(2), 185-192. Tran Tuan Dung, 2013. Characteristics of the structure - tectonic in the deep water of the East Sea of Vietnam based on interpretation of gravity and magnetic anomaly data. The 35th Conference of Vietnam Petroleum Institute, 55-66. Tran Tuan Dung, Bui Cong Que, Nguyen Hong Phuong, 2013. The Cenozoic basement structure of the Spratly Islands and adjacent areas by modeling and interpreting gravity data. Russian Journal of Pacific Geology. ISSN 1819-7140, 4, 227-236. http://geomag.org/models/emag2.html. http://www.ngdc.noaa.gov/geomag-web/#declination.

Synthesis of Gold Nanoparticles Conjugated with Protein A: Towards the Application in Biosensors for Virus Detection

In this article, a facile and effective technique is described to prepare a complex of gold nanoparticles (GNPs)/protein A (PrA) for biosensors in virus detection. GNPs were synthesized by the reduction of tetrachloroauric (III) acid trihydrate using sodium ascorbate, and then coated with PrA via ultracentrifugation. The complex of GNPs/PrA was characterized using UV-vis spectroscopy and transmission electron microscopy. The immunogold labeling method of scanning electron microscopy was also used to verify the capacity for the detection and binding of GNPs/PrA to H$_{1}$N$_{1}$ influenza A virus particles. The results showed that GNPs were spherical, uniform shape, and approximately 10 nm in size. Noticeably, the complex of GNPs/PrA could detect and bind effectively to H$_{1}$N$_{1}$ influenza A virus particles by a large number of GNPs surrounded. The advantage of the complex of GNPs/PrA showed a highly potential application in biosensors with the improvement of the sensitivity and transducing signal for virus detection

Đánh giá một số kỹ thuật phát hiện thư rác ứng dụng thuật toán xếp hạng người dùng trong mạng thư điện tử tại trường đại học Hà Nội

In this paper, four spam-filtering approaches based on user ranking in the mail networks: Clustering, Extended Clustering Coefficient, PageRank Algorithm and Weighted PageRank Algorithm are analyzed. We also propose a couple of fully worked-out datasets from the email network of Hanoi University against which the experimental comparisons with the respect to the accuracy of email user ranking and spam filtering are conducted. The results indicate that PageRank Algorithm and Extended Clustering Coefficient approaches are better than others. The rate of true detection is over 99.5%, while the failed alarm remains below 0.5%.Bài báo phân tích và kiểm nghiệm bốn phương pháp lọc thư rác dựa trên việc xếp hạng người dùng trong mạng thư điện tử: Phương pháp độ phân cụm, phương pháp độ phân cụm mở rộng, phương pháp sử dụng thuật toán PageRank và phương pháp sử dụng thuật toán PageRank có trọng số. Các thí nghiệm được thực hiện trên một số tập dữ liệu hoàn chỉnh của mạng thư điện tử Đại học Hà Nội. So sánh kết quả các thí nghiệm cho thấy, phương pháp sử dụng thuật toán PageRank và phương pháp độ phân cụm mở rộng mở rộng có kết quả tốt hơn các phương pháp còn lại. Tỷ lệ phát hiện thành công thư rác lên tới trên 99,5% trong khi tỷ lệ báo động nhầm thấp hơn 0,5%

An adaptive hierarchical sliding mode controller for autonomous underwater vehicles

The paper addresses a problem of efficiently controlling an autonomous underwater vehicle (AUV), where its typical underactuated model is considered. Due to critical uncertainties and nonlinearities in the system caused by unavoidable external disturbances such as ocean currents when it operates, it is paramount to robustly maintain motions of the vehicle over time as expected. Therefore, it is proposed to employ the hierarchical sliding mode control technique to design the closed-loop control scheme for the device. However, exactly determining parameters of the AUV control system is impractical since its nonlinearities and external disturbances can vary those parameters over time. Thus, it is proposed to exploit neural networks to develop an adaptive learning mechanism that allows the system to learn its parameters adaptively. More importantly, stability of the AUV system controlled by the proposed approach is theoretically proved to be guaranteed by the use of the Lyapunov theory. Effectiveness of the proposed control scheme was verified by the experiments implemented in a synthetic environment, where the obtained results are highly promising. © 2021 by the authors. Licensee MDPI, Basel, Switzerland. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Linh Nguyen" is provided in this record*

Tree diversity and species composition of tropical dry forests in Vietnam's Central Highlands Region

Abstract Tree species inventories, particularly of poorly known dry forests, are necessary to protect and restore them in degraded landscapes. The present research has been conducted to compare taxonomic diversity and community composition in four dry forests (DF) categories with different standing volume levels: very low (DFV), low (DFP), medium (DFM) and high (DFR). This quantitative assessment of taxonomic diversity, forest structure and species composition were obtained from 103 sample plots (0.1 ha each). The regeneration potential of trees was assessed in 515 subplots (4 m × 4 m) located within the 103 plots. A total of 1,072 trees representing 87 species belonging to 37 families were recorded in 10.3 ha of total sampled area. The ranges of diversity indices observed in the four forest types were: Margalef's (5.44–8.43), Shannon-Wiener (1.80–2.29), Simpson diversity (0.76–0.87) and evenness (0.32–0.35). The regeneration potential of rare and threatened species Dalbergia oliveri, Hopea recopei, Dalbergia bariensis, Sindora siamensis, Parashorea stellata was observed to be poor. Conversely, Cratoxylon formosum, Shorea obtusa, Dipterocarpus tuberculatus, Dipterocarpus obtusifolius, Terminalia alata, Shorea siamensis and Xylia xylocarpa were the most dominant species at the seedling and sapling stage, showing a strong potential for regeneration. Overall, this study provides useful information on tree species diversity and composition for tropical dry forests which can be used as baseline data to develop incoming plans for forest management and conservation in Vietnam's Central Highlands Region

THE INFRASTRUCTURE AND ENVIRONMENT IN THE OLD TENEMENTS IN HANOI

Joint Research on Environmental Science and Technology for the Eart