• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12B
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• pp.1227-1235
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• 2010

Stateflow is a useful system modeling tool, which is frequently used in industry. But Stateflow has defects when users are trying to describe consecutive behaviors or a system's temporal behaviors. Timing diagram, on the other hand, is a widely used tool of explaining behaviors of a hardware system in electronics. This tool has a merit when specifying consecutive behaviors and temporal behaviors of a system. Thus, this paper suggests $Stateflow_{TD}$, the unified modeling methodology in Stateflow domain integrating Stateflow with Timing diagram in order to improve the shortcomings of Stateflow. This paper not only explains a technique of integrating both a Stateflow model and Timing diagram models, and describes advantages of what $Stateflow_{TD}$ formalism has, but also shows its convenience using two example systems.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.7
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• pp.471-478
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• 2013

This paper proposes a black-box based test case generation method for Simulink/Stateflow model utilizing the RRT algorithm which is a method to efficiently solve the path planning for complicated systems. The proposed method in the paper tries to solve the reachability problem with the RRT algorithm, which has to be solved for black-box based test case generations. A major problem of the RRT based test case generation algorithms is that the cost such as running time and required memory size is too much for complicated Stateflow model. The typical RRT algorithm expands rapidly-exploring random tree (RRT) in a single state space. But the proposed method expands it in dynamic state space based on the state of Simulink model, consequently reducing the cost. In the paper, a new definition of RRT state space, a distance measure and a test case generation algorithm are proposed. The performance of proposed method is verified through the experiment against Stateflow model.

• The KIPS Transactions:PartD
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• v.17D no.4
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• pp.283-296
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• 2010

Timing diagram is a useful tool for describing the specification of system, but there is no study for test case strategy of a timing diagram. To solve this problem, we followed the steps to generate test cases from timing diagram in this paper. 1) We defined a timing diagram formally. 2) We describe the method of transforming from a timing diagram model into a Stateflow model which has an equivalent relationship between a timing diagram model and a transformed Stateflow model. 3) We generated test cases from a transformed Stateflow model using SDV which is plugged in Simulink. To show that our approach is useful, we made an experiment with a surveillance model and arbitrary timing diagram models. In the experiment we transformed timing diagram models into Stateflow models, generated test cases from transformed Stateflow models using SDV, and analyzed the generation results. The conclusion that can be obtained from this study is that timing diagram is not only a specification tool but also a useful tool when users are trying to generate test cases based on model.

• Journal of Aerospace System Engineering
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• v.1 no.2
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• pp.6-12
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• 2007

Flight modes of automatic flight control system for light general aviation flight deck. Garmin G1000, were realized using Stateflow. In developing aircraft, it is difficult to verify the operational flight program in particular branch statement because developer can not see any visual logical steam. So, Stateflow has been used to visualize logical stream, transition from one flight mode to another flight mode. The performance was approved by applying flight mode transition conditions of G1000 to proposed transition system that is composed of states, switches, events, data and transition conditions. DURMI-II was used as 6-DOF simulation model.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.12
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• pp.829-840
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• 2013

This paper proposes a modified RRT (Rapidly exploring Random Tree) algorithm utilizing a heuristic input analysis and suggests a test case generation method from Simulink/Stateflow model using the proposed RRT algorithm. Though the typical RRT algorithm is an efficient method to solve the reachability problem to definitely be resolved for generating test cases of model in a black box manner, it has a drawback, an inefficiency of test case generation that comes from generating random inputs without considering the internal states and the test targets of model. The proposed test case generation method increases efficiency of test case generation by analyzing the test targets to be satisfied at the current state and heuristically deciding the inputs of model based on the analysis during expanding an RRT, while maintaining the merit of RRT algorithm. The proposed method is evaluated with the models of ECUs embedded in a commercial passenger's car. The performance is compared with that of the typical RRT algorithm.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.11
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• pp.765-778
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• 2013

This paper proposes a test case generation method for Stateflow model using the extended RRT method. The RRT method which has been popularly used for planning paths for complex systems also shows a good performance for test case generation. However, it does not consider the test coverage which is important for test case generation. The proposed extension method hires the concept of test goal achievement to increase test coverage and drives RRT extension in the direction that increases the goal achievement. Considering the concept, a RRT distance metric, random node generation method and modified RRT extension algorithm are proposed. The effectiveness of proposed algorithm is compared with that of the typical RRT algorithm through the experiment using the practical automotive ECUs.

• KIPS Transactions on Software and Data Engineering
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• v.6 no.6
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• pp.293-302
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• 2017

This paper proposes a method that generates test cases from Simulink/Stateflow(SL/SF) using a SMT (Satisfiability Modulo Theory) solver, Yices and information of SL/SF model. The most difficult problem to generate test cases from SL/SF model is to solve reachability problem. In the propose method, Yices and the tables built with the model information are utilized to solve the reachability problem. The method utilizes the SMT model, that is the SL/SF model transformed in Yices. The tables built from SL/SF are used for backward processing of the proposed method and increases test generation efficiency. A commercial refrigerator model and two car ECU (Electrical Control Unit) models are used to evaluate the performance of the proposed algorithm..

• KIPS Transactions on Software and Data Engineering
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• v.5 no.12
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• pp.653-662
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• 2016

This paper describes a test case generation algorithm for Simulink/Stateflow models based on the Rapidly exploring Random Tree (RRT) algorithm that has been successfully applied to path finding. An important factor influencing the performance of the RRT algorithm is the metric used for calculating the distance between the nodes in the RRT space. Since a test case for a Simulink/Stateflow (SL/SF) model is an input sequence to check a specific condition (called a test target in this paper) at a specific status of the model, it is necessary to drive the model to the status before checking the condition. A status maps to a node of the RRT. It is usually necessary to check various conditions at a specific status. For example, when the specific status represents an SL/SF model state from which multiple transitions are made, we must check multiple conditions to measure the transition coverage. We propose a unique distance calculation metric, based on the observation that the test targets are gathered around some specific status such as an SL/SF state, named key nodes in this paper. The proposed metric increases the probability that an RRT is extended from key nodes by imposing penalties to non-key nodes. A test case generation algorithm utilizing the proposed metric is proposed. Three models of Electrical Control Units (ECUs) embedded in a commercial vehicle are used for the performance evaluation. The performances are evaluated in terms of penalties and compared with those of the algorithm using a typical RRT algorithm.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06b
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• pp.247-249
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• 2012

본 연구에서는 MATLAB Simulink/Stateflow 기반으로 만든 모델의 transition의 condition을 미리 연산하고, 이를 바탕으로 모델을 최적화하는 모듈을 제안하고 이를 구현하였다. 구현한 모듈은 stateflow 내부의 transition condition의 label string을 이진트리로 구성하고, True/False를 판단한다. 그리고 condition의 True/False 판단 결과를 통해 모델의 최적화 과정을 수행한다. 제안하는 모듈을 이용하여 간단한 예시모델의 수정 과정을 보이고 테스트 커버리지가 향상되는 것을 검증하였다.

• KIPS Transactions on Software and Data Engineering
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• v.8 no.6
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• pp.235-242
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• 2019

This paper proposes a reusable test case extraction technique for modified MATLAB Simulink/Stateflow (SL/SF) model. Creating test cases for complicated SL/SF model like ECU(Electrical Control Unit) of automotive, requires a lot of time and effort. An intuitive way to reduce to create new test cases whenever the model changes, is to reuse some test cases which have been generated for the original model. In this paper, we propose a method to define reusable test cases in SL/SF after defining model behavior and judging model equality by test cases. The proposed technique is evaluated using a commercial automotive controller model.