A subfamília Limnocorinae (Naucoridae) possui quatro gêneros nominais na literatura, entretanto, apenas Limnocoris Stål, 1860 é considerado válido. O presente estudo revisa taxonomicamente as espécies do gênero, bem como a relação filogenética entre elas. Todas as espécies ocorrem na região Neotropical, registradas do sul do Estado de Nevada, nos Estados Unidos, até a região central da Argentina. Historicamente, Limnocoris é um grupo pouco estudado, com trabalhos que concentram basicamente em descrições de espécies, muitas delas, publicadas em estudos isolados, sem muito detalhe. Além disso, é digno de nota mencionar que até o presente momento nenhum estudo que se objetivou classificar grupos de espécies ou mesmo a relação de gêneros dentro das subfamílias utilizando análise filogenética foi realizado até o momento. Através de revisão taxonômica, buscou-se reconhecer os táxons pertencentes ao gênero, bem como suas variações intraespecíficas. A revisão teve ênfase na localização do material-tipo e espécimes adicionais, sempre que possível. Todas as espécies estudadas foram fotografadas e examinadas com o intuito de padronizar o estudo morfológico externo do gênero. Após o estudo dos espécimes-tipo, foi possível propor 15 sinonímias novas, sinônimos juniores entre colchetes: Limnocoris dubiosus Montandon [L. aymarana Poisson]; L. espinolai Nieser & Lopez-Ruf [L. porphyros Nieser & Lopez- Ruf]; L. insularis Champion [L. alcorni La Rivers]; L. malkini La Rivers [L. pulchellus La Rivers]; L. menkei La Rivers [L. birabeni De Carlo]; L. ochraceus Montandon [L. maculatus De Carlo]; L. pallescens (Stål) [L. bergrothi Montandon]; L. pauper Montandon [L. nigropunctatus Montandon]; L. pauper Montandon [L. nigropunctatus Montandon]; L. pectoralis Montandon [L. rivalis Melin]; L. pygmaeus La Rivers [L. solenoides La Rivers]; L. signoreti Montandon [L. brailovskyi La Rivers, L. laucki La Rivers e L. stangei La Rivers]; L. stali Montandon [L. carcharus La Rivers e L. robustus Roback & Nieser]. Além disso, três espécies são revalidadas: L. montandoni La Rivers, L. sattleri De Carlo e L. stali; L. surinamensis stat. nov. é elavada ao status de espécies, e outras 13 espécies novas são propostas. Lectótipos são designados para L. aymarana, L. bergrothi, L. dubiosus e L. signoreti. Com o objetivo de propor uma hipótese de relação de parentesco entre as espécies de Limnocoris, foi elaborada uma matriz de 82 caracteres morfológicos, tendo como método de estudo a máxima parcimônia. A análise utilizando pesagem implícita resultou em 1 árvore mais parcimoniosa; oito sinapomorfias suportam a monofilia do gênero Limnocoris, que se mostrou dividir-se em dois grandes clados separados principalmente pela pubescência da região ventral do corpo. A distribuição geográfica de grande parte das espécies é incrementada com a inclusão de novos registros e, com intuito de facilitar a identificação, mapas de distribuição e uma chave ilustrada é proposta para as espécies estudadas. / The subfamily Limnocorinae (Naucoridae) contains four nominal genera in the literature, however, only Limnocoris Stål, 1860 is considered valid. The present study reviews taxonomically the species of the genus, as well as proposes a phylogenetic hypothesis of relation between them. All species occur in the Neotropical region, from southern Nevada in the United States, to central Argentina. Historically, Limnocoris is a poorly studied group, with works concentrate mainly on descriptions of species, many of them, published in isolated studies, without much detail. In addition, up to the present time no study that has aimed to classify groups of species or even the relationship of genera within the subfamilies using phylogenetic analysis has not been performed so far. Through a taxonomic revision, it was sought to recognize the taxa belonging to the genus, as well as their intraspecific variations. The revision has emphasized in the location of the type-material and additional specimens, whenever possible. All species studied were photographed and examined in order to standardize the external morphological study of the genus. After the study of the type specimens, it was possible to propose 15 new synonymies, junior synonyms between brackets: Limnocoris dubiosus Montandon [L. aymarana Poisson]; L. espinolai Nieser & Lopez-Ruf [L. porphyros Nieser & Lopez-Ruf]; L. insularis Champion [L. alcorni La Rivers]; L. malkini La Rivers [L. pulchellus La Rivers]; L. menkei La Rivers [L. birabeni De Carlo]; L. ochraceus Montandon [L. maculatus De Carlo]; L. pallescens (Stål) [L. bergrothi Montandon]; L. pauper Montandon [L. nigropunctatus Montandon]; L. pauper Montandon [L. nigropunctatus Montandon]; L. pectoralis Montandon [L. rivalis Melin]; L. pygmaeus La Rivers [L. solenoides La Rivers]; L. signoreti Montandon [L. brailovskyi La Rivers, L. laucki La Rivers e L. stangei La Rivers]; L. stali Montandon [L. carcharus La Rivers e L. robustus Roback & Nieser]. In addition, three species are revalidated: L. montandoni La Rivers, L. sattleri De Carlo and L. stali; L. surinamensis stat. nov. is elevated to species status and another 13 new species are proposed. Lectotypes are designated for L. aymarana, L. bergrothi, L. dubiosus e L. signoreti. With the aim of proposing a hypothesis of relationship among the species of Limnocoris, a matrix of 82 morphological characters was elaborated, having as method the maximum parsimony. The analysis under implicit weighing resulted in 1 more parsimonious tree; eight synapomorphies support the monophyly of the genus, which has been shown to divide into two clades separated mainly by the pubescence of the ventral region of the body. The geographic distribution of almost all species is increased with the inclusion of new records and, in order to facilitate identification, distribution maps and an identification key are proposed for the studied species.

A subfamília Limnocorinae (Naucoridae) possui quatro gêneros nominais na literatura, entretanto, apenas Limnocoris Stål, 1860 é considerado válido. O presente estudo revisa taxonomicamente as espécies do gênero, bem como a relação filogenética entre elas. Todas as espécies ocorrem na região Neotropical, registradas do sul do Estado de Nevada, nos Estados Unidos, até a região central da Argentina. Historicamente, Limnocoris é um grupo pouco estudado, com trabalhos que concentram basicamente em descrições de espécies, muitas delas, publicadas em estudos isolados, sem muito detalhe. Além disso, é digno de nota mencionar que até o presente momento nenhum estudo que se objetivou classificar grupos de espécies ou mesmo a relação de gêneros dentro das subfamílias utilizando análise filogenética foi realizado até o momento. Através de revisão taxonômica, buscou-se reconhecer os táxons pertencentes ao gênero, bem como suas variações intraespecíficas. A revisão teve ênfase na localização do material-tipo e espécimes adicionais, sempre que possível. Todas as espécies estudadas foram fotografadas e examinadas com o intuito de padronizar o estudo morfológico externo do gênero. Após o estudo dos espécimes-tipo, foi possível propor 15 sinonímias novas, sinônimos juniores entre colchetes: Limnocoris dubiosus Montandon [L. aymarana Poisson]; L. espinolai Nieser & Lopez-Ruf [L. porphyros Nieser & Lopez- Ruf]; L. insularis Champion [L. alcorni La Rivers]; L. malkini La Rivers [L. pulchellus La Rivers]; L. menkei La Rivers [L. birabeni De Carlo]; L. ochraceus Montandon [L. maculatus De Carlo]; L. pallescens (Stål) [L. bergrothi Montandon]; L. pauper Montandon [L. nigropunctatus Montandon]; L. pauper Montandon [L. nigropunctatus Montandon]; L. pectoralis Montandon [L. rivalis Melin]; L. pygmaeus La Rivers [L. solenoides La Rivers]; L. signoreti Montandon [L. brailovskyi La Rivers, L. laucki La Rivers e L. stangei La Rivers]; L. stali Montandon [L. carcharus La Rivers e L. robustus Roback & Nieser]. Além disso, três espécies são revalidadas: L. montandoni La Rivers, L. sattleri De Carlo e L. stali; L. surinamensis stat. nov. é elavada ao status de espécies, e outras 13 espécies novas são propostas. Lectótipos são designados para L. aymarana, L. bergrothi, L. dubiosus e L. signoreti. Com o objetivo de propor uma hipótese de relação de parentesco entre as espécies de Limnocoris, foi elaborada uma matriz de 82 caracteres morfológicos, tendo como método de estudo a máxima parcimônia. A análise utilizando pesagem implícita resultou em 1 árvore mais parcimoniosa; oito sinapomorfias suportam a monofilia do gênero Limnocoris, que se mostrou dividir-se em dois grandes clados separados principalmente pela pubescência da região ventral do corpo. A distribuição geográfica de grande parte das espécies é incrementada com a inclusão de novos registros e, com intuito de facilitar a identificação, mapas de distribuição e uma chave ilustrada é proposta para as espécies estudadas. / The subfamily Limnocorinae (Naucoridae) contains four nominal genera in the literature, however, only Limnocoris Stål, 1860 is considered valid. The present study reviews taxonomically the species of the genus, as well as proposes a phylogenetic hypothesis of relation between them. All species occur in the Neotropical region, from southern Nevada in the United States, to central Argentina. Historically, Limnocoris is a poorly studied group, with works concentrate mainly on descriptions of species, many of them, published in isolated studies, without much detail. In addition, up to the present time no study that has aimed to classify groups of species or even the relationship of genera within the subfamilies using phylogenetic analysis has not been performed so far. Through a taxonomic revision, it was sought to recognize the taxa belonging to the genus, as well as their intraspecific variations. The revision has emphasized in the location of the type-material and additional specimens, whenever possible. All species studied were photographed and examined in order to standardize the external morphological study of the genus. After the study of the type specimens, it was possible to propose 15 new synonymies, junior synonyms between brackets: Limnocoris dubiosus Montandon [L. aymarana Poisson]; L. espinolai Nieser & Lopez-Ruf [L. porphyros Nieser & Lopez-Ruf]; L. insularis Champion [L. alcorni La Rivers]; L. malkini La Rivers [L. pulchellus La Rivers]; L. menkei La Rivers [L. birabeni De Carlo]; L. ochraceus Montandon [L. maculatus De Carlo]; L. pallescens (Stål) [L. bergrothi Montandon]; L. pauper Montandon [L. nigropunctatus Montandon]; L. pauper Montandon [L. nigropunctatus Montandon]; L. pectoralis Montandon [L. rivalis Melin]; L. pygmaeus La Rivers [L. solenoides La Rivers]; L. signoreti Montandon [L. brailovskyi La Rivers, L. laucki La Rivers e L. stangei La Rivers]; L. stali Montandon [L. carcharus La Rivers e L. robustus Roback & Nieser]. In addition, three species are revalidated: L. montandoni La Rivers, L. sattleri De Carlo and L. stali; L. surinamensis stat. nov. is elevated to species status and another 13 new species are proposed. Lectotypes are designated for L. aymarana, L. bergrothi, L. dubiosus e L. signoreti. With the aim of proposing a hypothesis of relationship among the species of Limnocoris, a matrix of 82 morphological characters was elaborated, having as method the maximum parsimony. The analysis under implicit weighing resulted in 1 more parsimonious tree; eight synapomorphies support the monophyly of the genus, which has been shown to divide into two clades separated mainly by the pubescence of the ventral region of the body. The geographic distribution of almost all species is increased with the inclusion of new records and, in order to facilitate identification, distribution maps and an identification key are proposed for the studied species.

Informação relacionada a concertos de bugs tem sido explorada na construção de preditores de bugs cuja função é o suporte para a verificação de sistemas de software identificando quais elementos, como arquivos, são mais propensos a bugs. Uma grande variedade de métricas estáticas de código e métricas de mudança já foi utilizada para construir tais preditores. Dos muitos preditores de bugs propostos, a grande maioria foca em sistemas orientados à objeto. Apesar de orientação a objetos ser o paradigma de escolha para a maioria das aplicações, o paradigma procedural ainda é usado em várias — muitas vezes cruciais — aplicações, como sistemas operacionais e sistemas embarcados. Portanto, eles também merecem atenção. Essa dissertação extende o trabalho na área de predição de bugs ao avaliar e aprimorar preditores de bugs para sistemas procedurais de software. Nós proporcionamos três principais contribuições: (i) comparação das abordagens existentes de predição de bugs no contexto de sistemas procedurais, (ii) proposta de uso dos atributos de qualidade de software como atributos de predição no contexto estudado e (iii) avaliação dos atributos propostos em conjunto com a melhor abordagem encontrada em (i). Nosso trabalho provê, portanto, fundamentos para melhorar a performance de preditores de bugs no contexto de sistemas procedurais. / Information regarding bug fixes has been explored to build bug predictors, which provide support for the verification of software systems, by identifying fault-prone elements, such as files. A wide range of static and change metrics have been used as features to build such predictors. Many bug predictors have been proposed, and their main target is objectoriented systems. Although object-orientation is currently the choice for most of the software applications, the procedural paradigm is still being used in many—sometimes crucial—applications, such as operating systems and embedded systems. Consequently, they also deserve attention. This dissertation extends work on bug prediction by evaluating and tailoring bug predictors to procedural software systems. We provide three key contributions: (i) comparison of bug prediction approaches in context of procedural software systems, (ii) proposal of the use of software quality features as prediction features in the studied context, and (iii) evaluation of the proposed features in association with the best approach found in (i). Our work thus provides foundations for improving the bug prediction performance in the context of procedural software systems.

In today’s technology driven society, software is becoming increasingly important in more areas of our lives. The domain of software extends beyond the obvious domain of computers, tablets, and mobile phones. Smart devices and the internet-of-things have inspired the integra- tion of digital and computational technology into objects that some of us would never have guessed could be possible or even necessary. Fridges and freezers connected to social media sites, a toaster activated with a mobile phone, physical buttons for shopping, and verbally asking smart speakers to order a meal to be delivered. This is the world we live in and it is an exciting time for software engineers and computer scientists. The sheer volume of code that is currently in use has long since outgrown beyond the point of any hope for proper manual maintenance. The rate of which mobile application stores such as Google’s and Apple’s have expanded is astounding. The research presented here aims to shed a light on an emerging field of research, called Genetic Improvement ( GI ) of software. It is a methodology to change program code to improve existing software. This thesis details a framework for GI that is then applied to explore fitness landscape of bug fixing Python software, reduce execution time in a C ++ program, and integrated into a live system. We show that software is generally not fragile and although fitness landscapes for GI are flat they are not impossible to search in. This conclusion applies equally to bug fixing in small programs as well as execution time improvements. The framework’s application is shown to be transportable between programming languages with minimal effort. Additionally, it can be easily integrated into a system that runs a live web service.

Made available in DSpace on 2017-07-10T17:37:22Z (GMT). No. of bitstreams: 1 Ana_Paula_G_S_Wengrat.pdf: 2096466 bytes, checksum: eab7f1fa4bfc4b23b72f4b2bcd8697d8 (MD5) Previous issue date: 2016-08-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Species of Vatiga (Hemiptera: Tingidae) are pests of Cassava, Manihot esculenta Crantz (Euphorbiaceae), an important food source for more than 800 million people. Vatiga infestations in Cassava can cause serious production losses. Although importance economic, there are few research work about morphological description this species, relevant item in pest identification at the beginning of infestation and for use in phylogenetic analysis. Furthermore, not many records occur of Vatiga species and resistant genotypes to prague. That way, has been described and illustred the external morphology all the phases of V. illudens life, evaluated at resistance of five genotypes of cassava at this species and raising the occurence of insects of the genus Vatiga in Cassava comercial crops. About morphology, the eggs´s whitish, oblong-shaped and deposited inside of leaf. Nymphs, the dorsal surface of the head and body side margins have spikes; from the second to fifth instar the cephalic and lateral spikes become more visible, but in least amount that V. manihotae. Genotypic resistance showed that insects supplied Mecu 72 genotype had affected their development, thereby increasing nymphal and eggs-adults period, reducing significantly the fertility. The occurrence of the species recorded four species of Vatiga / As espécies de Vatiga (Hemiptera: Tingidae) são pragas da cultura da mandioca, Manihot esculenta Crantz (Euphorbiaceae), uma importante fonte de alimento para mais de 800 milhões de pessoas. Infestações de Vatiga em mandioca podem causar graves perdas de produtividade. Embora apresente importância econômica, são raros os trabalhos de descrição morfológica desta espécie, ítem relevante na identificação da praga já no inicio das infestações e para utilização em análises filogenéticas. Além disso, são escassos os registros de ocorrência das espécies de Vatiga e de genótipos resistentes à praga. Assim, foi descrita e ilustrada a morfologia externa de todas as fases de vida de V. illudens, avaliada a resistência de cinco genótipos de mandioca a esta espécie e levantada a ocorrência das espécies do gênero Vatiga em cultivos comerciais de mandioca. Acerca da morfologia, os ovos são esbranquiçados, oblongos e depositados no interior do tecido vegetal. Nas ninfas, a superfície dorsal da cabeça e margens laterais do corpo apresentam espinhos; a partir do segundo ao quinto ínstar os espinhos cefálicos e laterais tornam-se mais visíveis porém, em menor quantidade em relação à V. manihotae. Verificou-se que os insetos alimentados com o genótipo Mecu 72 tiveram seu desenvolvimento afetado, aumentando o período ninfal e de ovo-adulto e reduzindo significativamente a fecundidade. A ocorrência das espécies registrou quatro espécies de Vatiga

The Box Elder Bug, Leptocoria trivittatue (say), is a hanipterous insect belonging to the family corisidae. Although it rarely is a pest of agricultural crops, its habit of invading homes and other buildings for hibernation and to warm itself has made it an annoying household pest. It has proven to be a difficult insect to control. Only a few of the contact insecticides, useful in control of related insect pests, have given satisfactory control of the Boxelder Bug. Because it has not been considered a critical problem, it has not received detailed attention from the scientific investigators. Its close association with boxelder trees has long been recognized. Elimination of boxelder trees has often been advocated for control of this insect. However, boxelder is not its only host and, furthermore, elimination of boxelder trees is not always practical or desirable.

This study was begun in June 1935, and continued up to and including the fall of 1937. The work was carried out at the Davis county Experiment Farm at Farmington, Utah, with some survey work also having been done in the central and northern parts of the state. This work was made possible through the cooperation of the Entomological and Horticultural Departments of the Utah Agricultural Experiment Station. The green soldier bug, Acrosternum hilaris (Say), is also called the green stinkbug. Thomas Say was the first to describe this insect as belonging to the genus Pentatoma, but in some publications one may find it also listed under genera Nezara and Raphigaster. This insect is a native of this country and was first described in 1831. It is one of the serious insect pests of orchard fruit in Utah, and this study was undertaken for the purpose of learning the life history and feeding habits of the insect in this state.

Although bug tracking systems are fundamental to support virtually any software development process, they are currently suboptimal to support the needs and complexities of large communities. This dissertation first presents a study showing empirical evidence that the traditional interface used by current bug tracking systems invites much noise—unreliable, unuseful, and disorganized information—into the ecosystem. We find that noise comes from, not only low-quality contributions posted by inexperienced users or from conflicts that naturally arise in such ecosystems, but also from the difficulty of fitting the complex bug resolution process and knowledge into the linear sequence of comments that current bug tracking systems use to collect and organize information. Since productivity in bug tracking systems relies on bug reports with accessible and realible information, this leaves contributors struggling to work on and to make sense of the dumps of data submitted to bug reports and, thus, impacting productivity. Next generation bug tracking systems should be more than a tool for exchanging unstructured textual comments. They should be an ecosystem that is tailored for collaborative knowledge building, leveraging the power of the masses to collect reliable and useful information about bugs, providing mechanisms and incentives to verify the validity of such information and mechanisms to organize such information, thus, facilitating comprehension and reasoning. To bring bug tracking systems towards this vision, we present three orthogonal approaches aiming at increasing the usefulness and realiability of contributions and organizing information to improve understanding and reasoning. To improve the usefulness and realibility of contributions we propose the addition of game mechanisms to bug tracking systems, with the objective of motivating contributors to post higher-quality content. Through an empirical investigation of Stack Overflow we evaluate the effects of the mechanisms in such a collaborative software development ecosystem and map a promissing approach to use game mechanisms in bug tracking systems. To improve data organization, we propose two complementary approaches. The first is an automated approach to data organization, creating bug report summaries that make reading and working with bug reports easier, by highlighting the portions of bug reports that expert developers would focus on, if reading the bug report in a hurry. The second approach to improve data organization is a fundamental change on how data is collected and organized, eliminating comments as the main component of bug reports. Instead of comments, users contribute informational posts about bug diagnostics or solutions, allowing users to post contextual comments for each of the different diagnostic iiior solution posts. Our evaluations with real bug tracking system users find that they consider the bug report summaries to be very useful in facilitating common bug tracking system tasks, such as finding duplicate bug reports. In addition, users found that organzing content though diagnostic and solution posts to significanly facilitate reasoning about and searching for relevant information. Finally, we present future directions of work investigating how next generation bug tracking systems could combine the use of the three approaches, such that they benefit from and build upon the results of the other approaches. Next generation bug tracking systems should be more than a tool for exchanging unstructured textual comments. They should be an ecosystem that is tailored for collaborative knowledge building, leveraging the power of the masses to collect reliable and useful information about bugs, providing mechanisms and incentives to verify the validity of such information and mechanisms to organize such information, thus, facilitating comprehension and reasoning. To bring bug tracking systems towards this vision, we present three orthogonal approaches aiming at increasing the usefulness and realiability of contributions and organizing information to improve understanding and reasoning. To improve the usefulness and realibility of contributions we propose the addition of game mechanisms to bug tracking systems, with the objective of motivating contributors to post higher-quality content. Through an empirical investigation of Stack Overflow we evaluate the effects of the mechanisms in such a collaborative software development ecosystem and map a promissing approach to use game mechanisms in bug tracking systems. To improve data organization, we propose two complementary approaches. The first is an automated approach to data organization, creating bug report summaries that make reading and working with bug reports easier, by highlighting the portions of bug reports that expert developers would focus on, if reading the bug report in a hurry. The second approach to improve data organization is a fundamental change on how data is collected and organized, eliminating comments as the main component of bug reports. Instead of comments, users contribute informational posts about bug diagnostics or solutions, allowing users to post contextual comments for each of the different diagnostic iiior solution posts. Our evaluations with real bug tracking system users find that they consider the bug report summaries to be very useful in facilitating common bug tracking system tasks, such as finding duplicate bug reports. In addition, users found that organzing content though diagnostic and solution posts to significanly facilitate reasoning about and searching for relevant information. Finally, we present future directions of work investigating how next generation bug tracking systems could combine the use of the three approaches, such that they benefit from and build upon the results of the other approaches.

Testing is an indispensable mechanism for assuring software quality. One of the key issues in testing is to obtain a test data set that is able to effectively test an implementation. An adequate test data set consists of test cases that can expose faults in a software implementation. Mutation-based testing can be employed to obtain adequate test data sets, and numerous mutation operators have been proposed to date to measure the adequacy of test data sets that reveal functional faults. However, implementations that pass functionality tests are still vulnerable to malicious attacks. Despite the rigorous use of various existing testing techniques, many vulnerabilities are discovered after the deployment of software implementations, such as buffer overflows (BOF), SQL injections, and format string bugs (FSB). Successful exploitations of these vulnerabilities may result in severe consequences such as denial of services, application state corruptions, and information leakage. Many approaches have been proposed to detect these vulnerabilities. Unfortunately, very few approaches address the issue of testing implementations against vulnerabilities. Moreover, these approaches do not provide an indication whether a test data set is adequate for vulnerability testing or not. We believe that bringing the idea of traditional functional test adequacy to vulnerability testing can help address the issue of test adequacy. In this thesis, we apply the idea of mutation-based adequate testing to perform vulnerability testing of buffer overflows, SQL injections, and format string bugs. We propose mutation operators to force the generation of adequate test data sets for these vulnerabilities. The operators mutate source code to inject the vulnerabilities in the library function calls and unsafe implementation language elements. The mutants generated by the operators are killed by test cases that expose these vulnerabilities. We propose distinguishing or killing criteria for mutants that consider varying symptoms of exploitations. Three prototype tools are developed to automatically generate mutants and perform mutation analysis with input test cases and the effectiveness of the proposed operators is evaluated on several open source programs containing known vulnerabilities. The results indicate that the proposed operators are effective for testing the vulnerabilities, and the mutation-based vulnerability testing process ensures the quality of the applications against these vulnerabilities. / Thesis (Master, Computing) -- Queen's University, 2008-08-18 13:53:04.036

Software testing is crucial for uncovering software defects and ensuring software reliability. Symbolic execution has been utilized for automatic test generation to improve testing effectiveness. However, existing test generation techniques based on symbolic execution fail to take full advantage of programs’ rich amount of documentation specifying their input constraints, which can further enhance the effectiveness of test generation. In this paper we present a general approach, Document-Assisted Symbolic Execution (DASE), to improve automated test generation and bug detection. DASE leverages natural language processing techniques and heuristics to analyze programs’ readily available documentation and extract input constraints. The input constraints are then used as pruning criteria; inputs far from being valid are trimmed off. In this way, DASE guides symbolic execution to focus on those inputs that are semantically more important. We evaluated DASE on 88 programs from 5 mature real-world software suites: GNU Coreutils, GNU findutils, GNU grep, GNU Binutils, and elftoolchain. Compared to symbolic execution without input constraints, DASE increases line coverage, branch coverage, and call coverage by 5.27–22.10%, 5.83–21.25% and 2.81–21.43% respectively. In addition, DASE detected 13 previously unknown bugs, 6 of which have already been confirmed by the developers.