Scenario-based techniques, also known as scenario methods, have been actively employed to resolve intricate problems for engineering complex software systems. Scenarios are powerful tools that allow engineers to analyze the dynamics and contexts of complex systems. Despite the widespread use, there is a lack of a well-established reference framework that systematically organizes key concepts and attributes of scenarios. This has left engineers without a systematic guidance at the method level, hindering their ability to utilize the scenario methods effectively. To address the challenges associated with scenario methods, this study aims to provide a reference framework and modeling method. By conducting a literature review and suggesting a Conceptual Scenario Framework (CSF), we establish a conceptual basis that systematically presents the core concepts and characteristics of scenarios. Additionally, we introduce the Extensible Scenario Modeling Method (ESMM) that empowers engineers to perform scenario modeling and domain-specific extensions using the framework. With the inclusion of the Extensible Scenario Modeling Language (ESML), which comprises domain-general model types and classes for scenario description and ontological analysis, ESMM facilitates flexible design of domain-specific scenario elements through language-level extensions. This study assesses the proposed method in comparison to existing scenario development methods in the automated driving system domain. Through an analysis of their ability to represent scenario data, it was established that the language constructs of ESML possess semantic expressiveness suitable for serving as a reference framework. Furthermore, the findings from the case study validate the extensibility of ESMM for specialization in creating a scenario modeling language tailored to specific domains, while also effectively supporting the ontological analysis of particular application domains.

In recent years, a domain of Systems-of-Systems (SoS) has emerged due to the needs of utilizing collective and collaborative system capabilities. As interest in SoS engineering has grown, this study focuses on the model-based analysis and design of an SoS, and we propose a general-purpose modeling method for the model-based SoS engineering (MBSoSE). Based on requirements that modeling methods of MBSoSE approaches should fulfill, required model types are identified (19 model types) and they are classified on their different modeling purposes and concerns (6 model categories). Model types are meta-modeled using the ADOxx Metamodeling Platform and they are implemented as modeling languages in a tool, called SIMVA-SoS Modeler. Using the modeling tool developed, we designed two different SoS cases and their scenarios that can be utilized as inputs of simulation and verification tools. Through the case studies, overall applicability of our modeling method for MBSoSE is evaluated and specific modeling results are provided as base reference models.

Interactions between software components play a major role in the achievement of goals in complex systems, such as platooning System-of-Systems (SoS). A platooning SoS groups vehicles in order to increase their fuel efficiency and alleviates traffic congestion by enabling driving in close proximity using operation protocols. In a platooning SoS, the execution of typical operations, such as Leave or Merge, consists of 20 micro-operations on average. Owing to this overabundance of sub-operations, interaction failures in a specific operation sequence can occur in an SoS execution. Further, analyzing the root cause of such failures is highly time-consuming, due to the density of the constituent interactions. Existing techniques suffer from two limitations: (1) The majority of the root cause analysis techniques are not capable of isolating faulty interaction sequences, because they do not directly utilize interaction data; (2) The majority of the fault diagnosis techniques assume the preexamined fault knowledge base, which needs too high cost due to limited knowledge in an SoS. To effectively analyze interaction failures in an SoS, we propose a pattern-based faulty interaction analysis technique. To this end, an interaction model is first defined for an SoS, followed by the proposal of a suspicious interaction pattern mining algorithm. During the case study using a platooning simulator, the technique automatically abstracts interaction data from logs and extracts faulty interaction patterns, thereby enabling the identification of seven new unreported interaction failure scenarios. The conclusions of this study can enrich the general fault knowledge base for platooning SoS.

A System-of-Systems (SoS) is a collection of systems, which consists of independent constituent systems to achieve higher-level goals. As an SoS changes constantly due to external and internal factors, dynamic reconfiguration and evolutionary development must be performed effectively. To manage an SoS that has these characteristics, SoS managers and engineers need to model and verify an SoS that accommodates changes. While many researchers have proposed techniques for modeling and verifying an SoS, little attention has been paid to the verification of a continuously changing SoS. Since the size and complexity of SoSs are too great to apply existing verification techniques, an efficient verification method for dynamically changing SoSs is required. If we can detect the change-related goals of an SoS and the corresponding change-affected parts in an SoS model, we can slice the SoS model in our area of concern and verify the SoS model efficiently. This paper proposes SoS GaP slicer, a verification method that considers the dynamic reconfiguration and evolution of an SoS. Our method could save the cost of verifying the whole of an SoS model by an efficient statistical model checking for SoSs. The experimental results show the accuracy and efficiency of the proposed method.

Automated Graphical User Interface (GUI) testing is one of the most widely used techniques to detect faults in mobile applications (apps) and to test functionality and usability. GUI testing exercises behaviors of an application under test (AUT) by executing events on GUIs and checking whether the app behaves correctly. In particular, because Android leads in market share of mobile OS platforms, a lot of research on automated Android GUI testing techniques has been performed. Among various techniques, we focus on model-based Android GUI testing that utilizes a GUI model for systematic test generation and effective debugging support. Since test inputs are generated based on the underlying model, accurate GUI modeling of an AUT is the most crucial factor in order to generate effective test inputs. However, most modern Android apps contain a number of dynamically constructed GUIs that make accurate behavior modeling more challenging. To address this problem, we propose a set of multi-level GUI Comparison Criteria (GUICC) that provides the selection of multiple abstraction levels for GUI model generation. By using multilevel GUICC, we conducted empirical experiments to identify the influence of GUICC on testing effectiveness. Results show that our approach, which performs model-based testing with multi-level GUICC, achieved higher effectiveness than activity-based GUI model generation. We also found that multi-level GUICC can alleviate the inherent state explosion problems of existing a single-level GUICC for behavior modeling of real-world Android apps by flexibly manipulating GUICC.

Advanced robotic assistance in microsurgery, such as automation, requires an accurate estimation of the state of the robotic forceps. In this paper, we propose a robust and accurate forceps tracking method to estimate the full state of the forceps (i.e., the position, posture, and grip parameters) using visual information obtained from stereo microscopic images and kinematic information obtained from the robotic sensory information, forward kinematics, and hand-eye coordination. An online method for updating the hand-eye coordination was also developed using an extended Kalman filter to cancel the hand-eye coordination errors caused by the repositioning of the microscope. The experimental results showed that the proposed method could accurately and robustly estimate the state of the robotic forceps even after the repositioning of the microscope.

Forceps tracking is an important element of high-level surgical assistance such as visual servoing and surgical motion analysis. In many computer vision algorithms, artificial markers are used to enable robust tracking; however, markerless tracking methods are more appropriate in surgical applications due to their sterilizability. This paper describes a robust, efficient tracking algorithm capable of estimating the full state parameters of a robotic surgical instrument on the basis of projective contour modeling using a 3-D CAD model of the forceps. Thus, the proposed method does not require any artificial markers. The likelihood of the contour model was measured using edge distance transformation to evaluate the similarity of the projected CAD model to the microscopic image, followed by particle filtering to estimate the full state of the forceps. Experimental results in simulated surgical environments indicate that the proposed method is robust and time-efficient, and fulfills real-time processing requirements.

This paper presents the design and implementation of a reconfigurable heterogeneous modular architecture for service robots. The proposed architecture has five key concepts which are different from conventional reconfigurable modular service robots; 1) easy and multiple assembly according to requirements of users, 2) hardware resource sharing system with other heterogeneous modules, 3) communication ability among all heterogeneous modules which have different operating systems, 4) automatic connection management system when a new module is attached, 5) automatic software upgrading system for new module software. We explain the three parts of the system architecture which meet the five concepts; mechanical architecture, software architecture, and connection architecture. To verify our architecture, we developed and evaluated a reconfigurable heterogeneous modular service robot by applying the proposed design.