Thesis (M.Sc.)--Acadia University, 1998. / Includes bibliographical references (leaves 65-80). Also available on the Internet via the World Wide Web.

Thesis (M.Sc.)--Acadia University, 1998. / Includes bibliographical references (leaves 65-80). Also available on the Internet via the World Wide Web.

Submitted by LUIS RENATO JUNQUEIRA null (lrenatoj2@yahoo.com.br) on 2016-10-20T02:48:44Z No. of bitstreams: 1 Dissert_LRJ_corrigida.pdf: 5636293 bytes, checksum: 259084ad9da1cc625f5f79130569e026 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-10-20T19:36:38Z (GMT) No. of bitstreams: 1 junqueira_lr_me_bot.pdf: 5636293 bytes, checksum: 259084ad9da1cc625f5f79130569e026 (MD5) / Made available in DSpace on 2016-10-20T19:36:38Z (GMT). No. of bitstreams: 1 junqueira_lr_me_bot.pdf: 5636293 bytes, checksum: 259084ad9da1cc625f5f79130569e026 (MD5) Previous issue date: 2016-08-25 / Introduzido no início do século XX, o eucalipto, se adaptou bem a diversos locais no Brasil, sendo hoje o gênero florestal mais plantado no país. Dentre suas inúmeras utilizações, destacam-se a produção de celulose, papel, carvão e chapas de fibras. Desde o início dos anos 2000 houve a introdução de pragas exóticas, que devido à ausência competição e controle natural e presença de alimento e clima apropriados, tornaram-se problemas para os cultivos de eucalipto. Dentre as pragas introduzidas no país, destaca-se o percevejo bronzeado do eucalipto, Thaumastocoris peregrinus. Esta espécie teve sua detecção no Brasil em 2008 e desde então já atacou mais de 500 mil hectares de florestas. Contudo, ainda não existem informações consolidadas sobre as perdas ocasionas pelo seu ataque. Os objetivos deste trabalho foram quantificar a perda em produção de madeira causada por T. peregrinus sob duas situações: (1) utilizando-se como hospedeiro um mesmo clone em duas idades diferentes e (2) utilizando-se dois clones de eucalipto distintos em uma mesma idade. Para isolar o ataque de T. peregrinus os ensaios foram conduzidos em parcelas pareadas com aplicação de calda inseticida para proteger algumas parcelas de seu ataque. Para quantificar o impacto do ataque por T. peregrinus foram contados o número de insetos em folhas e armadilhas, mensuradas o crescimento em diâmetro e altura das árvores com posterior cálculo de volume. Os resultados mostraram redução em diâmetro, altura e volume devido ao ataque de T. peregrinus, com a técnica de aplicação de inseticidas pulverizados sendo mais eficiente que o método de drench. Como conclusões a perda potencial causada por T. peregrinus levando-se em consideração apenas um pico populacional da praga foi de R$ 1,4 mil/hectare. / Introduced in the early twentieth century, eucalypt has adapted well to different locations in Brazil, being the most planted genus in the country. Among its many uses, it highlights the production of pulp, paper, coal and fiberboard. Since early 2000s the introduction of exotic pests which encountered no competition or natural enemies and presence of food and suitable climate have become pests for eucalypt plantations. Among the main pests introduced in Brazil is the bronze bug, Thaumastocoris peregrinus. Its first detection in Brazil was in 2008 and since then it has attacked more than 500 thousands hectares of eucalypt forest. However, there are no consolidated information about growth losses caused by its attack. The objectives of this study were to quantify the loss in wood production caused by T. peregrinus in two situations: (1) using as a host the same material in two different ages and (2) using two different Eucalyptus materials in the same age. To isolate T. peregrinus attack the experiment were conducted in twin plots with insecticide spraying to protect trees from T. peregrinus attack. To quantify the impact caused by T. peregrinus attack the number of insects were counted on leaves and traps, the growth on diameter and height of trees were measured for subsequent volume calculation. The results showed a reduction in diameter, height and volume due to the attack of T. peregrinus. Insecticide spraying method got better results than drench method. As conclusions the potential loss caused by T. peregrinus taking into consideration only one pest outbreak was R$ 1.400, 00/ hectare.

Web applications provide the basis for the use of the "World-Wide-Web", as people know itnowadays. These software solutions get programmed by a numerous amount of developersall over the world. For all this software, it is not possible to guarantee a 100 percent security.Therefore, it is desirable that every application should get evaluated using penetration tests.Anewformof security testing platforms is getting provided by bug bounty programs, whichencourage the community to help searching for security breaches. This work introduces thecurrently leading portal for bug bounties, called Bugcrowd Inc. In addition, web applications,which were part of the program, got tested in order to evaluate their security level.A comparison is made with given statistics by leading penetration testing companies, showingthe average web application security level. The submission process, to send informationabout vulnerabilities, is getting evaluated. The average time it takes, to receive an answer regardinga submission is getting reviewed. In the end, the findings get retested, to evaluate, ifthe bug bounty program is a useful opportunity to increase security and if website operatorstake submissions serious by patching the software flaws.

Computer systems are deeply integrated into our daily routines such as online shopping, checking emails, and posting photos on social media platforms. Unfortunately, with the wide range of functionalities and sensitive information stored in computer systems, they have become fruitful targets for attackers. Cybersecurity ventures estimate that the cost of cyber attacks will reach $10.5 trillion USD annually by 2025. Moreover, data breaches have resulted in the leakage of millions of people’s social security numbers, social media account passwords, and healthcare information. With the increasing complexity and connectivity of computer systems, the intensity and volume of cyber attacks will continue to increase. Attackers will continuously look for bugs in the systems and ways to exploit them for gaining unauthorized access or leaking sensitive information. Minimizing bugs in systems is essential to remediate security weaknesses. To this end, researchers proposed a myriad of methods to discover bugs. In the software domain, one prominent method is fuzzing, the process of repeatedly running a program under test with “random” inputs to trigger bugs. Among different variants of fuzzing, greybox fuzzing (GF) has especially seen widespread adoption thanks to its practicality and bug-finding capability. In GF, the fuzzer collects feedback from the program (e.g., code coverage) during its execution and guides the input generation based on the feedback. Due to its success in finding bugs in the software domain, GF has gained traction in the hardware domain as well. Several works adapted GF to the hardware domain by addressing the differences between hardware and software. These works demonstrated that GF can be leveraged to discover bugs in hardware designs such as processors. In this thesis, we propose three different fuzzing mechanisms, one for software and two for hardware, to expose bugs in the multiple layers of systems. Each mechanism focuses on different aspects of GF to assist the fuzzing procedure for triggering bugs in hardware and software. The first mechanism, TargetFuzz, focuses on producing an effective seed corpus when fuzzing software. The seed corpus consists of a set of inputs serving as starting points to the fuzzer. We demonstrate that carefully selecting seeds to steer GF towards potentially buggy code regions increases the bug-finding capability of GF. Compared to prior works, TargetFuzz discovered 10 additional bugs and achieved 4.03× speedup, on average, in the total elapsed time for finding bugs. The second mechanism, DirectFuzz, adapts a specific variant of GF for software fuzzing, namely directed greybox fuzzing (DGF), to the hardware domain. The main use case of DGF in software is patch testing where the goal is to steer fuzzing towards recently modified code region. Similar to software, hardware design is an incremental and continuous process. Therefore, it is important to prioritize testing of a new component in a hardware design rather than previously well-tested components. DirectFuzz takes several differences between hardware and software (such as clock sensitivity, concurrent execution of multiple code fragments, hardware-specific coverage) into account to successfully adapt DGF to the hardware domain. DirectFuzz relies on coverage feedback applicable to a wide range of hardware designs and requires limited design knowledge. While this increases its ease of adoption to many different hardware designs, its effectiveness (i.e., bug-finding success) becomes limited in certain hardware designs such as processors. Overall, compared to a state-of-the-work hardware fuzzer, DirectFuzz covers specified targets sites (e.g., modified hardware regions) 2.23× faster. Our third mechanism named ProcessorFuzz relies on novel coverage feedback tailored for processors to increase the effectiveness of fuzzing in processors. Specifically, ProcessorFuzz monitors value changes in control and status registers which form the backbone of a processor. ProcessorFuzz addresses several drawbacks of existing works in processor fuzzing. Specifically, existing works can introduce significant instrumentation overhead, result in misleading guidance, and have lack of support for widely-used hardware languages. ProcessorFuzz revealed 8 new bugs in widely-used open source processors and identified bugs 1.23× faster than a prior work.

No description available.

Tarnished plant bug is the most important insect pest of cotton in Mississippi. Management of this insect is difficult because of insecticide resistance as well and the overwhelming population densities in many areas of the Mississippi Delta. Given the level of plant bug infestation and damage observed in cotton over the past several growing seasons, information is needed to improve management of vegetative growth once fruit retention is reduced. Little data exists regarding the impact of nitrogen application on infestation by tarnished plant bug. In addition, growers have been progressively reducing seeding rates as seed and technology fees have increased over the past 15 years. Although seeding rates have been reduced, nitrogen application recommendations have not changed. This research was initiated to determine the relationship between crop management factors and tarnished plant bug and to further refine N rate recommendations in the presence of reduced plant populations.

The tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), is the most important insect pest of cotton, Gossypium hirsutum (L.), in Mississippi. This research project was initiated to gain a better understanding of selected crop production factors that can improve tarnished plant bug integrated pest management. Results suggest that irrigation strategies and varietal pubescence can significantly influence tarnished plant bug management in cotton. Most notably, delaying irrigation for as long as possible and planting hairy varieties can minimize the impact of tarnished plant bug on cotton yields and reduce the number of insecticides needed to manage this pest. Additionally, these results show that tarnished plant bug management is most critical during the first four weeks of flowering. Results from these experiments will be used to improve the current integrated pest management program for tarnished plant bug in cotton and make cotton production more sustainable for Mississippi producers.

Stink bugs are the most economically important insect pest of soybeans in Mississippi. This study focused on several aspects of stink bug biology and management. One study examined the residual activity of certain insecticides. Rain was shown to reduce residual activity and after three days most insecticides provided very little control of stink bugs. Stink bugs complete at least one generation a year on early season hosts before moving into soybeans. A study of these early season hosts found that rice stink bug was more prevalent on grasses than the other hosts sampled. Brown stink bug was found on all hosts, while other species were not found very frequently. A third study to determine the effects of an automatic insecticide on insect populations in soybeans found that yield was not affected, but stink bug populations later in the year were lowered during the 2011 study.

No description available.