In formula-based fault localization methods, a program under test, which is unrolled to a certain... more In formula-based fault localization methods, a program under test, which is unrolled to a certain bound, is encoded in a trace formula (TF). The efficiency and precision of the fault localization algorithm depend highly on the way this formula is encoded. The full flow-sensitive TF can cover all potential root causes, but is usually large and scalability problems remain. We propose a new encoding, the hardened flow-sensitive trace formula (HFTF), which reduces the complexity of the formula but does not lose essential control flow graph (CFG) information required for localizing faults. The HFTF is constructed using a concolic execution method that generates both failing and successful executions and uses the coverage information from these executions to simplify the trace formula.
The paper tackles the problems of the “giant hairballs”, the dense and tangled structures often r... more The paper tackles the problems of the “giant hairballs”, the dense and tangled structures often resulting from visualization of large social graphs. Proposed is a high-dimensional rotation technique called AGI3D, combined with an ability to filter elements based on social centrality values. AGI3D is targeted for a high-dimensional embedding of a social graph and its projection onto 3D space. It allows the user to rotate the social graph layout in the high-dimensional space by mouse dragging of a vertex. Its high-dimensional rotation effects give the user an illusion that he/she is destructively reshaping the social graph layout but in reality, it assists the user to find a preferred positioning and direction in the high-dimensional space to look at the internal structure of the social graph layout, keeping it unmodified. A prototype implementation of the proposal called Social Viewpoint Finder is tested with about 70 social graphs and this paper reports four of the analysis results.
Nico Nico Douga (NND) is one of the most famous social media platforms for sharing videos in Japa... more Nico Nico Douga (NND) is one of the most famous social media platforms for sharing videos in Japan. There are 17 million videos posted to NND, for which users search by using keyword search and related video recommendation. However, it is difficult for the users to find interesting videos because videos generally are associated with only short texts and a few tags. In this paper, we present a method for clustering videos in NND by using the distribution of time-synchronized comments. Our method regards a video as the set of the users commenting on it and enables the clustering of videos based on users’ shared interests. In our experiment, we applied the proposed method to videos posted to NND, and evaluated our method by quantitatively comparing it with existing text-based methods and by qualitatively performing the subjective evaluation of clustering results. In the result of the quantitative evaluation, the proposed method showed a higher score of normalized mutual information than the existing methods when results of text-based methods and category metadata were used as correct results. The experimental results of the qualitative evaluation showed that the proposed method was as good as or better than the existing text-based methods.
. `Constraint hierarchy" is a nonmonotonic system that allowsprogrammers to ... more . `Constraint hierarchy" is a nonmonotonic system that allowsprogrammers to describe over-constrained real-world problems by specifyingconstraints with hierarchical preferences, and has been applied tovarious areas. An important aspect of constraint hierarchies is the existenceof efficient satisfaction algorithms based on local propagation. However,past local-propagation algorithms have been limited to multi-wayequality constraints. We overcome this by reformulating constraint...
Testing-based formal verification with symbolic execution (TBFV-SE) checks whether programs corre... more Testing-based formal verification with symbolic execution (TBFV-SE) checks whether programs correctly implement their formal specification. Given a formal specification and a program, it first derives a theorem expressing the correctness property of the executed program paths and then formally verifies the validity of the theorem. However, such theorems still need to be verified manually due to the lack of a tool support for dealing with expressions involved. In this paper, we propose a method for automatically verifying theorems for TBFV-SE. This method uses an SMT solver to check whether a theorem is valid. For this purpose, the method converts the conditions in the theorems written in the SOFL specification language into appropriate constraints that are supported by the SMT solver. We present a tool to support the method, and present two case studies to demonstrate how the tool works in the context of Java programs and SOFL specifications.
In formula-based fault localization methods, a program under test, which is unrolled to a certain... more In formula-based fault localization methods, a program under test, which is unrolled to a certain bound, is encoded in a trace formula (TF). The efficiency and precision of the fault localization algorithm depend highly on the way this formula is encoded. The full flow-sensitive TF can cover all potential root causes, but is usually large and scalability problems remain. We propose a new encoding, the hardened flow-sensitive trace formula (HFTF), which reduces the complexity of the formula but does not lose essential control flow graph (CFG) information required for localizing faults. The HFTF is constructed using a concolic execution method that generates both failing and successful executions and uses the coverage information from these executions to simplify the trace formula.
The paper tackles the problems of the “giant hairballs”, the dense and tangled structures often r... more The paper tackles the problems of the “giant hairballs”, the dense and tangled structures often resulting from visualization of large social graphs. Proposed is a high-dimensional rotation technique called AGI3D, combined with an ability to filter elements based on social centrality values. AGI3D is targeted for a high-dimensional embedding of a social graph and its projection onto 3D space. It allows the user to rotate the social graph layout in the high-dimensional space by mouse dragging of a vertex. Its high-dimensional rotation effects give the user an illusion that he/she is destructively reshaping the social graph layout but in reality, it assists the user to find a preferred positioning and direction in the high-dimensional space to look at the internal structure of the social graph layout, keeping it unmodified. A prototype implementation of the proposal called Social Viewpoint Finder is tested with about 70 social graphs and this paper reports four of the analysis results.
Nico Nico Douga (NND) is one of the most famous social media platforms for sharing videos in Japa... more Nico Nico Douga (NND) is one of the most famous social media platforms for sharing videos in Japan. There are 17 million videos posted to NND, for which users search by using keyword search and related video recommendation. However, it is difficult for the users to find interesting videos because videos generally are associated with only short texts and a few tags. In this paper, we present a method for clustering videos in NND by using the distribution of time-synchronized comments. Our method regards a video as the set of the users commenting on it and enables the clustering of videos based on users’ shared interests. In our experiment, we applied the proposed method to videos posted to NND, and evaluated our method by quantitatively comparing it with existing text-based methods and by qualitatively performing the subjective evaluation of clustering results. In the result of the quantitative evaluation, the proposed method showed a higher score of normalized mutual information than the existing methods when results of text-based methods and category metadata were used as correct results. The experimental results of the qualitative evaluation showed that the proposed method was as good as or better than the existing text-based methods.
. `Constraint hierarchy" is a nonmonotonic system that allowsprogrammers to ... more . `Constraint hierarchy" is a nonmonotonic system that allowsprogrammers to describe over-constrained real-world problems by specifyingconstraints with hierarchical preferences, and has been applied tovarious areas. An important aspect of constraint hierarchies is the existenceof efficient satisfaction algorithms based on local propagation. However,past local-propagation algorithms have been limited to multi-wayequality constraints. We overcome this by reformulating constraint...
Testing-based formal verification with symbolic execution (TBFV-SE) checks whether programs corre... more Testing-based formal verification with symbolic execution (TBFV-SE) checks whether programs correctly implement their formal specification. Given a formal specification and a program, it first derives a theorem expressing the correctness property of the executed program paths and then formally verifies the validity of the theorem. However, such theorems still need to be verified manually due to the lack of a tool support for dealing with expressions involved. In this paper, we propose a method for automatically verifying theorems for TBFV-SE. This method uses an SMT solver to check whether a theorem is valid. For this purpose, the method converts the conditions in the theorems written in the SOFL specification language into appropriate constraints that are supported by the SMT solver. We present a tool to support the method, and present two case studies to demonstrate how the tool works in the context of Java programs and SOFL specifications.
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Papers by Hiroshi Hosobe