Indoor assistance for visually impaired people using a RGB-D camera

In this paper a navigational aid for visually impaired people is presented. The system uses a RGB-D camera to perceive the environment and implements self-localization, obstacle detection and obstacle classification. The novelty of this work is threefold. First, self-localization is performed by means of a novel camera tracking approach that uses both depth and color information. Second, to provide the user with semantic information, obstacles are classified as walls, doors, steps and a residual class that covers isolated objects and bumpy parts on the floor. Third, in order to guarantee real time performance, the system is accelerated by offloading parallel operations to the GPU. Experiments demonstrate that the whole system is running at 9 Hz

DEWATS dissemination in Vietnam: achievements and lessons learnt

The speedy economic development and rapid growth of population and urbanization in Vietnam have created great pressure on the environment by its manufacturing process and human activities. Thus, it is necessary to protect the environment through policies and appropriate technology for the sustainable development of the country. The DEcentralized WAstewater Treatment Solutions (DEWATS) dissemination in Vietnam is one of the measures contributing to address this issue

Robust adaptive controller for wheel mobile robot with disturbances and wheel slips

In this paper an observer based adaptive control algorithm is built for wheel mobile robot (WMR) with considering the system uncertainties, input disturbances, and wheel slips. Firstly, the model of the kinematic and dynamic loops is shown with presence of the disturbances and system uncertainties. Next, the adaptive controller for nonlinear mismatched disturbance systems based on the disturbances observer is presented in detail. The controller includes two parts, the first one is for the stability purpose and the later is for the disturbances compensation. After that this control scheme is applied for both two loops of the system. In this paper, the stability of the closed system which consists of two control loops and the convergence of the observers is mathematically analysed based on the Lyapunov theory. Moreover, the proposed model does not require the complex calculation so it is easy for the implementation. Finally, the simulation model is built for presented method and the existed one to verify the correctness and the effectiveness of the proposed scheme. The simulation results show that the introduced controller gives the good performances even that the desired trajectory is complicated and the working condition is hard

Unravelling the economic impact of climate change in Vietnam's Mekong River Delta and Southeast region

Vietnam faces a heightened susceptibility to natural disasters stemming from climate change, yet the impact of these disasters varies markedly across its regions. Consequently, it is imperative to scrutinize the climatic factors affecting the regional economy, with a particular dearth of research addressing the nexus between natural threats and the economies of the Mekong River Delta and the Southeast region of Vietnam. The primary objective is to investigate how temperature fluctuations, rising sea levels, storms, and forest fires can detrimentally affect agriculture, forestry, and infrastructure in these regions. The present research uses the secondary data from Vietnam's General Statistics Office and the German Agency for International Cooperation. Employing quantitative analysis, the study endeavours to assess and compare the influence of climate change elements on the economic trajectories of the Mekong River Delta and the Southeast region. The findings reveal that the Mekong River Delta is disproportionately impacted by economic losses attributed to rising sea levels when juxtaposed with other regions in Vietnam. Firstly, the escalating sea levels significantly jeopardize residential and agricultural land in the Mekong River Delta (1). Secondly, while wildfires inflict damage on forestry in both the Mekong River Delta and the Southeast area, their overall impact is deemed negligible (2). Thirdly, the study ascertains that houses in the Mekong River Delta and the Southeast region remain relatively unscathed by storms (3). However, it is noted that specific storms have inflicted substantial damage on both regions (4). In light of these findings, future research should delve deeper into the analysis of storm risks in the Mekong River Delta and the Southeast region. Such insights are crucial for enhancing our understanding of the vulnerabilities and devising effective strategies to mitigate the economic repercussions of climate change in these pivotal areas

Pisachini planthoppers of Vietnam: new records of Pisacha and a new Goniopsarites species from Central Vietnam (Hemiptera, Fulgoromorpha, Nogodinidae)

Two planthopper species of the family Nogodinidae are added to the fauna of Vietnam, both from two localities in Thua Thien-Hue Province: Bach Ma National Park and Phong Dien District. The first species belongs to Goniopsarites Meng, Wang & Wang, 2014, G. mientrunganus Constant & Pham, sp. nov., and the second belongs to Pisacha Distant, 1906, P. yinggensis Meng, Wang & Wang, 2014. Pisacha yinggensis was previously recorded from Hainan Island, China. These new records greatly extend the distribution of both genera, which were known from southern China, Hainan and North Vietnam, to the south, reaching the mid area of Central Vietnam. Sexual dimorphism is reported in P. yinggensis for the first time. Illustrations of habitus and male terminalia of the new species are given as well as distribution maps and photographs of live specimens and their habitat. The family Nogodinidae now comprises nine species in Vietnam, with three of them present in Bach Ma National Park

Insight into the effect of zinc oxide nanoparticles coated multi-walled carbon nanotubes (ZnO/MWCNTs) on the thermal conductivity of epoxy nanocomposite as an electrical-insulating coating

The effect of zinc oxide (ZnO) nanoparticles on the thermal conductivity of zinc oxide/multi-walled carbon nanotubes (ZnO/MWCNTs) nanocomposite electrical-insulating coating was investigated. ZnO/MWCNTs was prepared by sol–gel method and incorporated into the epoxy matrix by ultrasonic-mechanical mixing to form the nanocomposite (ZnO/MWCNTs/epoxy). The SEM, XRD, and TGA analysis results showed that ZnO nanoparticles with 3–4 nm size formed layers on MWCNTs wires with a 10-nm diameter. The formed ZnO/CNT nanofillers had a diameter about 20–40 nm and had a highly homogeneous dispersion in the epoxy matrix. The thermal property of the nanocomposites was examined by the thermal imaging method. It was found that both MWCNTs and ZnO/MWCNTs nanofillers have significantly enhanced the thermal conduction of composites even at a low content load of 0.25 wt%. The thermal conductivity of ZnO/MWCNTs/epoxy and MWCNTs/epoxy composites was 0.62 and 1.09 Wm−1 K−1 respectively. The formation of ZnO nanoparticles on MWCNTs was thus led to a decreasing of about 43% in thermal conductivity of the composite. However, the thermal conduction of the ZnO/MWCNTs/epoxy composite is significantly improved about 210% compared to that of neat epoxy. These results proposed a useful method to modify the surface of MWCNTs for the fabrication of epoxy nanocomposite where electrical-insulating and thermal conducting are both required. The composite was applied as an insulating edge coating for capacitive deionization electrodes