Performance study of a COTS Distributed DBMS adapted for multilevel security

Multilevel secure database management system (MLS/DBMS) products no longer enjoy direct commercial-off-the-shelf (COTS) support. Meanwhile, existing users of these MLS/DBMS products continue to rely on them to satisfy their multilevel security requirements. This calls for a new approach to developing MLS/DBMS systems, one that relies on adapting the features of existing COTS database products rather than depending on the traditional custom design products to provide continuing MLS support. We advocate fragmentation as a good basis for implementing multilevel security in the new approach because it is well supported in some current COTS database management systems. We implemented a prototype that utilises the inherent advantages of the distribution scheme in distributed databases for controlling access to single-level fragments; this is achieved by augmenting the distribution module of the host distributed DBMS with MLS code such that the clearance of the user making a request is always compared to the classification of the node containing the fragments referenced; requests to unauthorised nodes are simply dropped. The prototype we implemented was used to instrument a series of experiments to determine the relative performance of the tuple, attribute, and element level fragmentation schemes. Our experiments measured the impact on the front-end and the network when various properties of each scheme, such as the number of tuples, attributes, security levels, and the page size, were varied for a Selection and Join query. We were particularly interested in the relationship between performance degradation and changes in the quantity of these properties. The performance of each scheme was measured in terms of its response time. The response times for the element level fragmentation scheme increased as the numbers of tuples, attributes, security levels, and the page size were increased, more significantly so than when the number of tuples and attributes were increased. The response times for the attribute level fragmentation scheme was the fastest, suggesting that the performance of the attribute level scheme is superior to the tuple and element level fragmentation schemes. In the context of assurance, this research has also shown that the distribution of fragments based on security level is a more natural approach to implementing security in MLS/DBMS systems, because a multilevel database is analogous to a distributed database based on security level. Overall, our study finds that the attribute level fragmentation scheme demonstrates better performance than the tuple and element level schemes. The response times (and hence the performance) of the element level fragmentation scheme exhibited the worst performance degradation compared to the tuple and attribute level schemes

Adamawa primary education research: final report

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Adamawa primary education research: executive summary

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On the Security of Information Dissemination in the Internet-of-Vehicles

Internet of Vehicles (IoV) is regarded as an emerging paradigm for connected vehicles to exchange their information with other vehicles using vehicle-to-vehicle (V2V) communications by forming a vehicular ad hoc networks (VANETs), with roadside units using vehicle-to-roadside (V2R) communications. IoV offers several benefits such as road safety, traffic efficiency, and infotainment by forwarding up-to-date traffic information about upcoming traffic. For instance, IoV is regarded as a technology that could help reduce the number of deaths caused by road accidents, and reduce fuel costs and travel time on the road. Vehicles could rapidly learn about the road condition and promptly respond and notify drivers for making informed decisions. However, malicious users in IoV may mislead the whole communications and create chaos on the road. Data falsification attack is one of the main security issues in IoV where vehicles rely on information received from other peers/vehicles. In this paper, we present data falsification attack detection using hashes for enhancing network security and performance by adapting contention window size to forward accurate information to the neighboring vehicles in a timely manner (to improve throughput while reducing end-to-end delay). We also present clustering approach to reduce travel time in case of traffic congestion. Performance of the proposed approach is evaluated using numerical results obtained from simulations. We found that the proposed adaptive approach prevents IoV from data falsification attacks and provides higher throughput with lower delay

Endocrine and Growth Disorders in Children with Haemoglobin-SS

Background: Suboptimal growth and certain metabolic disorders are commonly presented by children with Sickle Cell Disease (SCD). SCD is an autosomal recessive genetic condition common in regions with intense malaria prevalence. The cycles of de-oxygenation and oxygenation of redblood cells producing repeated sickling and unsickling, leading to red cell damage is a concern. There was need to establish the cause of common triggers for Vaso-Occlusive crises which include dehydration, infections, extreme temperature and emotional stress. Recurrent painful episodes, several physical and biochemical disorders including suboptimal growth, low immunity, anemia and a variety of serious organ system complications that cause life-long disabilities and/or early death in HbSS patients was a challenge. The highest frequencies (3 to 4% of populations) of Homozygous Sickle Cell disease occur in Sub-Saharan Africa. Methodology: Twenty eight children aged 4-10 years with Hemoglobin-SS (HbSS) and Vaso-Occlusive crisis attending Children Emergency Clinic at  Ladoke Akintola University of Technology Teaching Hospital and another 30 healthy sex and age matched children with HbAA (controls) participatedin this study. Plasma levels of Growth Hormone(GH), cortisol, prolactin, Total Thyroxin(TT4), Total Triiodotyronine(TT3), Thyroid Stimulating  Hormone(TSH) and insulin were determined in all respondents using enzyme linked immunosorbent assay methods. Results: The weight, height and BMI decreased significantly (p<0.05) in HbSS children compared with the controls. Plasma levels of GH, cortisol, TT3 and TT4 increased significantly (p<0.05) in HbSS-children compared with controls. Plasma levels of prolactin, TSH and insulin did not show significant (p>0.05) changes in the HbSS children compared with the controls. There was a significant (r=0.46, p=0.04) positive correlation between cortisol and GH in the children with HbSS. A negative correlation (r=-0.45, p=0.045) existed between TT4 and weight of HbSSchildren. Conclusion: The lower levels of height, weight and BMI despite increased plasma level of GH could suggest peripheral tissue resistance and/or GH-receptor deficiency in HbSS children. Elevated cortisol levels and the positive correlation between cortisol and GH could suggest a link between metabolic stress and GH secretion in HbSS Children. Key words: Hormones, growth disorders, Haemoglobin-SS(HbSS

Performance study of a COTS distributed DBMS adapted for multilevel security

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