Vehicular Ad hoc Networks (VANETs) are the promising approach to provide safety and other applications to the drivers as well as passengers. It becomes a key component of the intelligent transport system. A lot of works have been done towards it but security in VANET got less attention. In this article, we have discussed about the VANET and its technical and security challenges. We have also discussed some major attacks and solutions that can be implemented against these attacks. We have compared the solution using different parameters. Lastly we have discussed the mechanisms that are used in the solutions.
The past decade has seen episodes of increasingly severe air pollution across much of the highly populated Indo-Gangetic Plain (IGP), particularly during the post-monsoon season when crop residue burning (CRB) is most prevalent. Recent studies have suggested that a major, possibly dominant contributor to this air quality decline is that northwest (NW) Indian rice residue burning has shifted later into the post-monsoon season, as an unintended consequence of a 2009 groundwater preservation policy that delayed the sowing of irrigated rice paddy. Here we combine air quality modelling of fine particulate matter (PM2.5) over IGP cities, with meteorology, fire and smoke emissions data to directly test this hypothesis. Our analysis of satellite-derived agricultural fires shows that an approximate 10 d shift in the timing of NW India post-monsoon residue burning occurred since the introduction of the 2009 groundwater preservation policy. For the air quality crisis of 2016, we found that NW Indian CRB timing shifts made a small contribution to worsening air quality (3% over Delhi) during the post-monsoon season. However, if the same agricultural fires were further delayed, air quality in the CRB source region (i.e. Ludhiana) and for Delhi could have deteriorated by 30% and 4.4%, respectively. Simulations for other years highlight strong inter-annual variabilities in the impact of these timing shifts, with the magnitude and even direction of PM2.5 concentration changes strongly dependent on specific meteorological conditions. Overall we find post-monsoon IGP air quality to be far more sensitive to meteorology and the amount of residue burned in the fields of NW India than to the timing shifts in residue burning. Our study calls for immediate actions to provide farmers affordable and sustainable alternatives to residue burning to hasten its effective prohibition, which is paramount to reducing the intensity of post-monsoon IGP air pollution episodes.
To mitigate the problems of demand-supply mismatch in the future grid the solution of renewable energy source (RES) integration results in a bidirectional flow of information and transactions, which are prone to different kinds of cyber attacks, especially in energy trading where the security of financial transactions is of most concern. Electric vehicle (EV) having the advantage of mobility can play a significant role in maintaining demand-supply balance at any location unlike their peers (conventional compensator). For deciding entire system security, securing EVs charging-discharging transactions at all charging stations or connecting points is most important. The system can be made more secure against cyber-attacks with the introduction of the blockchain framework. Hence, in view of secured transactions, the paper focuses on the energy trading process between EVs and distribution network (DN) in a Byzantine based blockchain consensus framework. During peak load period DN initiates the energy trading process by demanding additional power from the EVs. This process of energy trading results in energy and information exchange which needs to be secured through blockchain from vulnerable attacks and threats. Possible scenarios of various cyber-attacks on different nodes of the system are visualized in the form of false data. To highlight the application of blockchain, the Byzantine general problem framework is used which states that for successful attack 33% of information is to be manipulated, in other words, decreasing the probability of attack confirms the system security. Numerical results based on various operating scenarios for the standard IEEE 33 bus system are in agreement with the Byzantine consensus problem indicating improvement in system security.INDEX TERMS Blockchain, Byzantine general problem, consensus, energy trading, security.
The fundamental motivation of this modeling study, which uses regional chemical transport models (Weather Research and Forecasting–Community Multiscale Air Quality Modelling System), is to distill the chemical, physical, and meteorological basis for the ultrahigh concentrations of fine particulate matter particles (PM2.5) over India. The study performed detailed source apportionment sensitivity studies with an updated sectoral emission inventory at 36 × 36 km resolution and the most recent meteorological data from the European Center for Medium-range Weather Forecasting. The Indo-Gangetic Plain (IGP) emerges as the most polluted region. PM2.5 concentrations over IGP and IGP cities like Delhi have year-round values of at least 80 μg·m–3 compared with World Health Organization guidelines of 5–15μg·m–3. Peak pollution levels of 150–230 μg·m–3 in IGP occur from October through February, largely because of up to a fivefold drop in the ventilation coefficient and a lack of precipitation in winter in addition to increased emissions due to biomass burning. Emissions of primary particles (black carbon, dust, metals, and primary organics) contribute 38% of PM2.5 concentrations in India, while the remaining 62% is of secondary origin through gas-to-particle conversion. Cooking and heating with solid biomass contribute one-third of the PM2.5. Fossil fuel sources contribute 30%, largely as secondary aerosols. Emission inventories for black carbon may be underestimating emissions by a factor of 3. In major IGP cities like Delhi, the regional transport of particulates and gaseous pollutants emitted from various sources upwind play a major role in the PM2.5. Providing access to clean energy to the biomass dependent 500 million people and switching from fossil fuels to renewable energy sources would eliminate more than 60% of the PM2.5 over India, including the heavily polluted IGP.
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