37,145 research outputs found
Targeted Greybox Fuzzing with Static Lookahead Analysis
Automatic test generation typically aims to generate inputs that explore new
paths in the program under test in order to find bugs. Existing work has,
therefore, focused on guiding the exploration toward program parts that are
more likely to contain bugs by using an offline static analysis.
In this paper, we introduce a novel technique for targeted greybox fuzzing
using an online static analysis that guides the fuzzer toward a set of target
locations, for instance, located in recently modified parts of the program.
This is achieved by first semantically analyzing each program path that is
explored by an input in the fuzzer's test suite. The results of this analysis
are then used to control the fuzzer's specialized power schedule, which
determines how often to fuzz inputs from the test suite. We implemented our
technique by extending a state-of-the-art, industrial fuzzer for Ethereum smart
contracts and evaluate its effectiveness on 27 real-world benchmarks. Using an
online analysis is particularly suitable for the domain of smart contracts
since it does not require any code instrumentation---instrumentation to
contracts changes their semantics. Our experiments show that targeted fuzzing
significantly outperforms standard greybox fuzzing for reaching 83% of the
challenging target locations (up to 14x of median speed-up)
Evidence of Fueling of the 2000 New Economy Bubble by Foreign Capital Inflow: Implications for the Future of the US Economy and its Stock Market
Previous analyses of a large ensemble of stock markets have demonstrated that
a log-periodic power law (LPPL) behavior of the prices constitutes a qualifying
signature of speculative bubbles that often land with a crash. We detect such a
LPPL signature in the foreign capital inflow during the bubble on the US
markets culminating in March 2000. We detect a weak synchronization and lag
with the NASDAQ 100 LPPL pattern. We propose to rationalize these observations
by the existence of positive feedback loops between market-appreciation /
increased-spending / increased-deficit-of-balance-of-payment /
larger-foreign-surplus / increased-foreign-capital-inflows and so on. Our
analysis suggests that foreign capital inflow have been following rather than
causing the bubble. We then combine a macroeconomic analysis of feedback
processes occurring between the economy and the stock market with a technical
analysis of more than two hundred years of the DJIA to investigate possible
scenarios for the future, three years after the end of the bubble and deep into
a bearish regime. We also detect a LPPL accelerating bubble on the EURO against
the US dollar and the Japanese Yen. In sum, our analyses is in line with our
previous work on the LPPL ``anti-bubble'' representing the bearish market that
started in 2000.Comment: 41 Latex pages including 14 eps figure
Active Learning: Effects of Core Training Design Elements on Self-Regulatory Processes, Learning, and Adaptability
This research describes a comprehensive examination of the cognitive, motivational, and emotional processes underlying active learning approaches, their effects on learning and transfer, and the core training design elements (exploration, training frame, emotion-control) and individual differences (cognitive ability, trait goal orientation, trait anxiety) that shape these processes. Participants (N = 350) were trained to operate a complex computer-based simulation. Exploratory learning and error-encouragement framing had a positive effect on adaptive transfer performance and interacted with cognitive ability and dispositional goal orientation to influence trainees’ metacognition and state goal orientation. Trainees who received the emotion-control strategy had lower levels of state anxiety. Implications for developing an integrated theory of active learning, learner-centered design, and research extensions are discussed
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