Security Improvement of Unicast Management Frames In Ieee 802.11 Mac Layer

Wireless Local Area Network (WLAN) or IEEE 802.11, was formed in 1990 to exchange information by using radio frequency rather than wires. This standard transmits information by three types of frame: data frame, control frame, and management frame. To provide security for WLANs, different security protocols have been designed such as: wired equivalent privacy (WEP), wifi protected access (WPA), and the strongest one, IEEE 802.11i (WPA2). Unfortunately all of the mentioned protocols provide security only for data frame. Control and management frames are transmitted without any protection even in IEEE 802.11i. The lack of protection on management frames causes an intruder to launch different types of attack on the WLAN such as forgery, session hijacking, denial of service and man-in-the-middle attack, which can lead to expose the whole WLAN. To address the problem, this thesis proposes and evaluates a new per frame security model which is called Management Frame with Integrity and Authentication (MFIA) to authenticate transmitted management frames. The proposed model uses a secret key and a new random sequence number (RSN) to secure communication between devices in WLAN and to prevent intruder from exposing the WLAN. The proposed model checks the authentication of a sender and the integrity of the management frames. The proposed model has been evaluated by quantifying the probability of finding a proper RSN by intruder, probability of different current common attacks on management frames, and also required time for the specified attacks. The results show that MFIA provides a high security level for management frames in all IEEE 802.11 standards. Required times to launch the attacks, show that allocating the specified time by intruder is almost impossible in the proposed model so that makes the mentioned attacks impractical. Results also show the proposed model can prevent a variety of attacks on management frames

Hybrid LTE-802.11ac network: Qos optimality evaluation of the voip codecs techniques

In response to the growing demand for higher quality Voice over IP (VoIP) communication, there are multiple high-speed access links, including Wi-Fi and Long Term Evolution (LTE) for the mobile end-users. The combination of the access links provides a hybrid network environment in which the end-users can switch from one to another, whichever provides a higher level of VoIP quality of service (QoS). Apart from the type of the access link, the VoIP codecs are also another key factor that directly affects the overall QoS of the voice communication. Due to inherent characteristics, different networks have distinct limitations and requirements. Considering these differences, the visualizing and analysing the performance and behaviour of each codec on its underlying network will lead to a proper VoIP codec selection, which in turn will result in optimal voice QoS for the mobile end-users. This study proposes a method to quantify and analyse the performance of different VoIP codecs in a hybrid LTE-802.11ac network in which the mobile end-users have two corresponding network interface cards. The aim is to find the codecs that suit the most for LTE and 802.11ac networks and thereby optimize the QoS of the VoIP communication. The NS3 tool is used to develop and implement a variety of distinct scenarios within which different QoS performance metrics are precisely measured. The obtained results signify the extensive impact of the codecs on the QoS of the voice communication for both LTE and 802.11ac users and also the importance of the VoIP codec selection procedure for each network

A new security model to prevent denial-of-service attacks and violation of availability in wireless networks

Wireless networks are deployed in many critical areas, such as health care centers, hospitals, police departments, and airports. In these areas, communication through the networks plays a vital role, and real-time connectivity along with constant availability of the networks is highly important. However, one of the most serious threats against the networks availability is the denial-of-service attacks. In wireless networks, clear text form of control frames is a security flaw that can be exploited by the attackers to bring the wireless networks to a complete halt. To prevent the denial-of-service attacks against the wireless networks, we propose two distinct security models. The models are capable of preventing the attacks by detecting and discarding the forgery control frames belonging to the attackers. The models are implemented and evaluated under various experiments and trials. The results have proved that the proposed models significantly improve the security performance of the wireless networks. This gives advantage of safe communication that can substantially enhance the network availability while maintaining the quality of the network performance

Validating reliability of OMNeT++ in wireless networks DoS attacks: simulation vs. testbed.

Despite current 802.11i security protocol, wireless net- works are vulnerable to Denial of Service (DoS) attacks. Sending a continuous stream of forgery control frames by an attacker can easily flood wireless channel so that the network cannot be available for its associated users. These attacks are possible because wireless control frames do not carry any cryptographic mechanism to detect and discard forgery frames. In this research in parallel to our experiments, we develop an extension module for wireless DoS attacks using OMNeT ++ to assess the reliability of this simulation tool in compare to our real 802.11 wireless network testbed. To fulfill these goals, throughput, end- to-end delay, and pocket lost ratio are considered as our performance measures running on both real testbed and simulation model. The results are used as a comparative acceptance of the simulation environment. Hereby we can confirm accuracy of the simulation results and OMNeT ++ in wireless DoS attack domai

An experimental evaluation of DoS attack and its impact on throughput of IEEE 802.11 wireless networks

a variety of locations. This has lead to development of high level security protocols for WLAN. The newest protocol IEEE 802.11i ratified to provide strong data encryption but it can not prevent Denial of Service (DoS) attacks on WLAN. This paper in a testbed, conducts an experimental framework to implement and quantify common types of DoS attacks against WLAN throughput. The results of implementation of our experiments shows that how easily DoS attacks can be performed on WLAN which causes to reduce throughput of communication considerably to make inaccessible wireless connection for its authorized members

Biosynthesis of metallic nanoparticles using plant extracts and evaluation of their antibacterial properties

The increasing attention being paid to metallic nano particles (MNPs) is due to their intensive applications in different areas of science such as medicine, chemistry, agriculture, and biotechnology. The main methods for nanoparticle production are chemical and physical approaches that are often costly and potentially harmful to the environment. Since the eco-friendly synthesis of NPs with different chemical compositions, sizes, shapes and controlled dispersity is an important aspect of nano biotechnology and green nanotechnology, biosynthesis of nanoparticles has been proposed as a cost-effective and environmental-friendly alternative to chemical and physical methods. Plants contain abundant natural compounds such as alkaloids, flavonoids, saponins, steroids, tannins and other nutritional compounds. These natural products are derived from various parts of the plant such as leaves, stems, roots, shoots, flowers, barks, fruits and seeds. Since the plant extract contains various secondary metabolites, it acts as the reducing and stabilizing agent for the bioreduction reaction to synthesize the novel metallic nanoparticles. This approach has been actively pursued in recent years as an alternative, efficient, inexpensive, and environmentally safe method for producing nanoparticles with specified properties. The present review focuses on the synthesis of MNPs with particular emphasis on biological synthesis using plant extracts and most commonly proposed mechanisms regarding the antibacterial properties of nanoparticles

Relationship between Salivary Alkaline Phosphatase Enzyme Activity and The Concentrations of Salivary Calcium and Phosphate Ions

Although salivary alkaline phosphatase (ALP) can balance de- and remineralization processes of enamel, there is no evidence regarding its effects on the concentrations of calcium and phosphate in saliva. The present study aims to determine the relationship between salivary ALP activity and the concentrations of calcium and phosphate in saliva. In this cross-sectional study, we evaluated salivary markers in 120 males, ages 19 to 44 years. All participants provided 5 mL of unstimulated whole saliva and the level of enzyme activity as well as calcium and phosphate concentrations were measured using a colorimetric method. Data were gathered and analyzed by statistical package for social sciences (SPSS) 13.00 using Pearson correlation test. A p value of <0.05 was considered statistically significant. The mean age of participants in the present study was 32.95 ± 8.09 years. The mean pH of saliva was 6.65 ± 0.62. Salivary parameters included average ALP activity (5.04 ± 1.866 U/dL), calcium (4.77 ± 0.877 mg/dL) and phosphate (10.38 ± 2.301 mg/dL). Pearson correlation test showed no significant relationship between ALP activity and calcium and phosphate concentrations in saliva (p>0.05). According to the results of the present study, there was no significant relation between salivary ALP activity and calcium and phosphate concentrations in saliva. However, further research is highly recommended

Alcohol sensing properties of nanosized thick film WO3 doped with Y2O3

In this paper the response of printed thick-film of WO3 doped by Y2O3 to organic solvent was studied. Different ratio of doping was prepared and changes of film resistance at different temperature in present of vaporized types of alcohol were observed. The results showed a high sensitivity of the film of 80.1%WO3-18.8%Y2O3 to Toluene, Xylene, Methanol, and 2-Propanone (Acetone) at 250, 450, and 550 °C, and higher sensitivity of 94.3%WO3-4.7%Y2O 3 at 350 °C. Microscopic images of the samples including SEM and TEM were observed. EDX and XRD analysis onto the samples also were done

Renal Function and Risk Factors of Moderate to Severe Chronic Kidney Disease in Golestan Province, Northeast of Iran

Introduction: The incidence of end-stage renal disease is increasing worldwide. Earlier studies reported high prevalence rates of obesity and hypertension, two major risk factors of chronic kidney disease (CKD), in Golestan Province, Iran. We aimed to investigate prevalence of moderate to severe CKD and its risk factors in the region. Methods: Questionnaire data and blood samples were collected from 3591 participants (≥18 years old) from the general population. Based on serum creatinine levels, glomerular filtration rate (GFR) was estimated. Results: High body mass index (BMI) was common: 35.0 of participants were overweight (BMI 25-29.9) and 24.5 were obese (BMI ≥30). Prevalence of CKD stages 3 to 5 (CKD-S3-5), i.e., GFR &lt;60 mL/min/1.73 m2, was 4.6. The odds ratio (OR) and 95 confidence interval (95 CI) for the risk of CKD-S3-5 associated with every year increase in age was 1.13 (1.11- 1.15). Men were at lower risk of CKD-S3-5 than women (OR = 0.28; 95 CI 0.18-0.45). Obesity (OR = 1.78; 95 CI 1.04-3.05) and self-reported diabetes (OR = 1.70; 95 CI 1.00-2.86), hypertension (OR = 3.16; 95 CI 2.02-4.95), ischemic heart disease (OR = 2.73; 95 CI 1.55-4.81), and myocardial infarction (OR = 2.69; 95 CI 1.14-6.32) were associated with increased risk of CKD-S3-5 in the models adjusted for age and sex. The association persisted for self-reported hypertension even after adjustments for BMI and history of diabetes (OR = 2.85; 95 CI 1.77-4.59). Conclusion: A considerable proportion of inhabitants in Golestan have CKD-S3-5. Screening of individuals with major risk factors of CKD, in order to early detection and treatment of impaired renal function, may be plausible. Further studies on optimal risk prediction of future end-stage renal disease and effectiveness of any screening program are warranted. © 2010 Najafi et al

Global, regional, and national burden of chronic kidney disease, 1990–2017 : a systematic analysis for the Global Burden of Disease Study 2017

Background Health system planning requires careful assessment of chronic kidney disease (CKD) epidemiology, but data for morbidity and mortality of this disease are scarce or non-existent in many countries. We estimated the global, regional, and national burden of CKD, as well as the burden of cardiovascular disease and gout attributable to impaired kidney function, for the Global Burden of Diseases, Injuries, and Risk Factors Study 2017. We use the term CKD to refer to the morbidity and mortality that can be directly attributed to all stages of CKD, and we use the term impaired kidney function to refer to the additional risk of CKD from cardiovascular disease and gout. Methods The main data sources we used were published literature, vital registration systems, end-stage kidney disease registries, and household surveys. Estimates of CKD burden were produced using a Cause of Death Ensemble model and a Bayesian meta-regression analytical tool, and included incidence, prevalence, years lived with disability, mortality, years of life lost, and disability-adjusted life-years (DALYs). A comparative risk assessment approach was used to estimate the proportion of cardiovascular diseases and gout burden attributable to impaired kidney function. Findings Globally, in 2017, 1·2 million (95% uncertainty interval [UI] 1·2 to 1·3) people died from CKD. The global all-age mortality rate from CKD increased 41·5% (95% UI 35·2 to 46·5) between 1990 and 2017, although there was no significant change in the age-standardised mortality rate (2·8%, −1·5 to 6·3). In 2017, 697·5 million (95% UI 649·2 to 752·0) cases of all-stage CKD were recorded, for a global prevalence of 9·1% (8·5 to 9·8). The global all-age prevalence of CKD increased 29·3% (95% UI 26·4 to 32·6) since 1990, whereas the age-standardised prevalence remained stable (1·2%, −1·1 to 3·5). CKD resulted in 35·8 million (95% UI 33·7 to 38·0) DALYs in 2017, with diabetic nephropathy accounting for almost a third of DALYs. Most of the burden of CKD was concentrated in the three lowest quintiles of Socio-demographic Index (SDI). In several regions, particularly Oceania, sub-Saharan Africa, and Latin America, the burden of CKD was much higher than expected for the level of development, whereas the disease burden in western, eastern, and central sub-Saharan Africa, east Asia, south Asia, central and eastern Europe, Australasia, and western Europe was lower than expected. 1·4 million (95% UI 1·2 to 1·6) cardiovascular disease-related deaths and 25·3 million (22·2 to 28·9) cardiovascular disease DALYs were attributable to impaired kidney function. Interpretation Kidney disease has a major effect on global health, both as a direct cause of global morbidity and mortality and as an important risk factor for cardiovascular disease. CKD is largely preventable and treatable and deserves greater attention in global health policy decision making, particularly in locations with low and middle SDI