scholarly journals The Optimization of a Symbolic Execution Engine for Detecting Runtime Errors

2017 ◽  
Vol 23 (2) ◽  
pp. 573-597
Author(s):  
István Kádár
Keyword(s):  
Search Strategy ◽  
Symbolic Execution ◽  
Real Life ◽  
Time Frame ◽  
Basic Block ◽  
Test Execution ◽  
Execution Engine ◽  
Branching Points ◽  
Java Programs ◽  
Null Pointer

In a software system, most of the runtime failures may come to light only during test execution, and this may have a very high cost. To help address this problem, a symbolic execution engine called RTEHunter, which has been developed at the Department of Software Engineering at the University of Szeged, is able to detect runtime errors (such as null pointer dereference, bad array indexing, division by zero) in Java programs without actually running the program in a real-life environment. Applying the theory of symbolic execution, RTEHunter builds a tree, called a symbolic execution tree, composed of all the possible execution paths of the program. RTEHunter detects runtime issues by traversing the symbolic execution tree and if a certain condition is fulfilled the engine reports an issue. However, as the number of execution paths increases exponentially with the number of branching points, the exploration of the whole symbolic execution tree becomes impossible in practice. To overcome this problem, different kinds of constraints can be set up over the tree. E.g. the number of symbolic states, the depth of the execution tree, or the time consumption could be restricted. Our goal in this study is to find the optimal parametrization of RTEHunter in terms of the maximum number of states, maximum depth of the symbolic execution tree and search strategy in order to find more runtime issues in a shorter time. Results on three open-source Java systems demonstrate that more runtime issues can be detected in the 0 to 60 basic block-depth levels than in deeper ones within the same time frame. We also developed two novel search strategies for traversing the tree based on the number of null pointer references in the program and on linear regression that performs better than the default depth-first search strategy.

Ethical Issues in the Fast Fashion Industry

2018 ◽  
Vol 9 (8) ◽  
pp. 660-665
Author(s):  
Chi Sheh ◽  
◽  
Peng Chan ◽  
Wen Jun Sim ◽  
◽  
...  
Keyword(s):  
Business Ethics ◽  
Conceptual Model ◽  
Ethical Issues ◽  
Real Life ◽  
Time Frame ◽  
Fashion Industry ◽  
Fast Fashion ◽  
Life Event ◽  
Real Cost ◽  
Literature Reviews

Fast fashion is becoming more and more popular nowadays and this industry is growing rapidly. In order to supply to the big demand of fast fashion clothing, company will need to increase the production of the clothing in shorter time frame. Besides that, to out beat the competitor, company will provide more choices of clothing in cheaper price to the customers. By practicing these actions to increase the business profits, company is behaving unethical to the manufacturer of the cloth. Most consumers are not aware of these ethical issues. This paper is will used and tested the conceptual model of fast fashion business ethics based on literature reviews. The finding from this paper will manifest the “real cost” of a cheap and branded fast fashion clothing and will be supported by real life event that happened. However, after realizing the problems, some company did make some changes and the solutions are stated in the paper as well.

scholarly journals Scaling Up Intervention Studies to Investigate Real-Life Foreign Language Learning in School

2019 ◽  
Vol 39 ◽  
pp. 161-188 ◽  
Author(s):  
Detmar Meurers ◽  
Kordula De Kuthy ◽  
Florian Nuxoll ◽  
Björn Rudzewitz ◽  
Ramon Ziai
Keyword(s):  
Language Learning ◽  
Large Scale ◽  
Intervention Studies ◽  
Full Range ◽  
Real Life ◽  
Foreign Language Learning ◽  
Time Frame ◽  
Field Trials ◽  
Web Based ◽  
Gold Standard Method

AbstractIntervention studies typically target a focused aspect of language learning that is studied over a relatively short time frame for a relatively small number of participants in a controlled setting. While for many research questions, this is effective, it can also limit the ecological validity and relevance of the results for real-life language learning. In educational science, large-scale randomized controlled field trials (RCTs) are seen as the gold standard method for addressing this challenge—yet they require intervention to scale to hundreds of learners in their varied, authentic contexts.We discuss the use of technology in support of large-scale interventions that are fully integrated in regular classes in secondary school. As an experimentation platform, we developed a web-based workbook to replace a printed workbook widely used in German schools. The web-based FeedBook provides immediate scaffolded feedback to students on form and meaning for various exercise types, covering the full range of constructions in the seventh-grade English curriculum.Following the conceptual discussion, we report on the first results of an ongoing, yearlong RCT. The results confirm the effectiveness of the scaffolded feedback, and the approach makes students and learning process variables accessible for the analysis of learning in a real-world context.

scholarly journals Test case generation for object-oriented imperative languages in CLP

2010 ◽  
Vol 10 (4-6) ◽  
pp. 659-674 ◽  
Author(s):  
MIGUEL GÓMEZ-ZAMALLOA ◽  
ELVIRA ALBERT ◽  
GERMÁN PUEBLA
Keyword(s):  
Symbolic Execution ◽  
Object Oriented ◽  
Test Case Generation ◽  
Test Case ◽  
Test Cases ◽  
Software Development Process ◽  
Java Programs ◽  
Promising Application ◽  
Account Due ◽  
Imperative Language

AbstractTesting is a vital part of the software development process. Test Case Generation (TCG) is the process of automatically generating a collection of test-cases which are applied to a system under test. White-box TCG is usually performed by means of symbolic execution, i.e., instead of executing the program on normal values (e.g., numbers), the program is executed on symbolic values representing arbitrary values. When dealing with an object-oriented (OO) imperative language, symbolic execution becomes challenging as, among other things, it must be able to backtrack, complex heap-allocated data structures should be created during the TCG process and features like inheritance, virtual invocations and exceptions have to be taken into account. Due to its inherent symbolic execution mechanism, we pursue in this paper that Constraint Logic Programming (CLP) has a promising application field in tcg. We will support our claim by developing a fully CLP-based framework to TCG of an OO imperative language, and by assessing it on a corresponding implementation on a set of challenging Java programs.

Improving Similarity Measure for Java Programs Based on Optimal Matching of Control Flow Graphs

2015 ◽  
Vol 25 (07) ◽  
pp. 1171-1197 ◽  
Author(s):  
Dehong Qiu ◽  
Jialin Sun ◽  
Hao Li
Keyword(s):  
Graph Matching ◽  
Control Flow ◽  
Basic Block ◽  
New Approach ◽  
Java Program ◽  
Java Programs ◽  
Instruction Sequences ◽  
High Level ◽  
Flow Graphs ◽  
Basic Blocks

Measuring program similarity plays an important role in solving many problems in software engineering. However, because programs are instruction sequences with complex structures and semantic functions and furthermore, programs may be obfuscated deliberately through semantics-preserving transformations, measuring program similarity is a difficult task that has not been adequately addressed. In this paper, we propose a new approach to measuring Java program similarity. The approach first measures the low-level similarity between basic blocks according to the bytecode instruction sequences and the structural property of the basic blocks. Then, an error-tolerant graph matching algorithm that can combat structure transformations is used to match the Control Flow Graphs (CFG) based on the basic block similarity. The high-level similarity between Java programs is subsequently calculated on the matched pairs of the independent paths extracted from the optimal CFG matching. The proposed CFG-Match approach is compared with a string-based approach, a tree-based approach and a graph-based approach. Experimental results show that the CFG-Match approach is more accurate and robust against semantics-preserving transformations. The CFG-Match approach is used to detect Java program plagiarism. Experiments on the collection of benchmark program pairs collected from the students’ submission of project assignments demonstrate that the CFG-Match approach outperforms the comparative approaches in the detection of Java program plagiarism.

scholarly journals EFFICACY AND SAFETY OF ADALIMUMAB IN ANKYLOSING SPONDYLITIS: DATA FROM REAL LIFE

2015 ◽  
Vol 24 (1) ◽  
pp. 44-49
Author(s):  
Claudiu Popescu ◽  
◽  
Cristina Coroama ◽  
Costin Mitulescu ◽  
Denisa Predeteanu ◽  
...  
Keyword(s):  
Ankylosing Spondylitis ◽  
Adverse Events ◽  
Clinical Setting ◽  
Demyelinating Disease ◽  
Real Life ◽  
Time Frame ◽  
University Hospital ◽  
Controlled Trials ◽  
Efficacy And Safety ◽  
Serious Adverse Events

Rationale. Data from controlled trials showed that adalimumab, a humanized anti-TNF monoclonal antibody, is effective and safe in the treatment of ankylosing spondylitis (AS). Objectives. The present study aimed to observe the effi cacy and safety of adalimumab in AS in a real life clinical setting. Methods. The study observed cross-sectionaly and retrospectively the efficacy and safety of adalimumab in all the patients admitted to the Rheumatology Department of “Sfânta Maria” Clinical Hospital between January 2008 and June 2013 who were classified as having AS according to the modified New York criteria. The diagnosis and follow-up of uveitic cases were done in the Ophthalmology Department of the Emergency University Hospital. Results. Within the study time-frame, 79 AS patients met the inclusion criteria: 71 (89.9%) had adalimumab for at least 24 months; 8 (10.1%) switched from adalimumab to another biological, as follows: 3 (3.8%) because of serious adverse events, 3 (3.8%) were primary non-responders and 2 (2.5%) were secondary non-responders. The clinical response was fast: after 3 months of treatment, 59 (83.1%) patients had BASDAI < 4 and 55 (77.5%) patients had BASFI < 4. Regarding safety, the serious adverse effects recorded were: infectious arthritis, pulmonary tuberculosis, pulmonary sarcoidosis. There were no cases of cancer or demyelinating disease during the study frame. Conclusions. Therapy with adalimumab in AS produces a prompt and lasting effect. The efficacy (remission) and safety (adverse events) of adalimumab can be monitored in the real-life clinical setting using BASDAI, BASFI, and routine clinical evaluations. Clinicians may need to expect a slightly higher rate of serious adverse events and rate of treatment discontinuation than those reported by controlled trials.

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