SafeSlice: A model slicing and design safety inspection tool for SysML

Software safety certification involves checking that the software design meets the (software) safety requirements. In practice, inspections are one of the primary vehicles for ensuring that safety requirements are satisfied by the design. Unless the safety-related aspects of the design are clearly delineated, the inspections conducted by safety assessors would have to consider the entire design, although only small fragments of the design may be related to safety. In a model-driven development context, this means that the assessors have to browse through large models, understand them, and identify the safety-related fragments. This is time-consuming and error-prone, specially noting that the assessors are often third-party regulatory bodies who were not involved in the design. To address this problem, we describe in this paper a prototype tool called, SafeSlice, that enables one to automatically extract the safety-related slices (fragments) of design models. The main enabler for our slicing technique is the traceability between the safety requirements and the design, established by following a structured design methodology that we propose. Our work is grounded on SysML, which is being increasingly used for expressing the design of safety-critical systems. We have validated our work through two case studies and a control experiment which we briefly outline in the paper. © 2011 ACM

On system sequence descriptions

Context: Use cases (UCs) are widely used to specify the functionality of a SW system. A UC is usually worked out in a Main Success Scenario and several other (Alternative) Scenarios. To make the overall structure of the UC clear and to prepare for the software implementing the UC, these scenarios must be integrated into one structure per UC. Question/problem: How to integrate the different scenarios of a UC into one structure? Our solution: We propose so-called (textual) System Sequence Descriptions (SSDs). We introduce a suitable (context-free) grammar for our SSDs. We can express all usual constructs with our SSDs, such as primary and secondary actors, basic steps, the internal responsibilities of the system, sequential composition, arbitrary order, loops/repetition, conditionals, alternatives, options, choices, definitions, and calls/'Includes'. To support validation of the resulting SSDs (with integrated scenarios) and check it with the users (Requirements quality assessment), we give (inductive) translation rules to translate the SSDs to natural language (Natural Language Generation for RE). Additionally, we give (inductive) rules to generate graphical SSDs (like the more familiar UML-diagrams) from our textual SSDs. This might support validation too. Results: With this new artefact design we can easily integrate the different scenarios of a UC into one clear SSD and also check the result with the users. That integrated SSD clarifies the overall structure of the UC and forms a suitable basis for implementation. With a nontrivial example we illustrate that the proposed grammar is very practical and that the approach scales up easily. Main contribution: The paper describes novel technical solutions for the application of NL-technologies to RE-relevant artefacts. The paper includes additional solutions to the RE-problem of validation

Effectiveness of Rational- Emotive- Behavior Group Counseling (REBT) on Irrational Attitudes about Spouse Selection in Girls and Boys

The purpose of present study was to determine the effectiveness of Rational- Emotional- Behavior therapy (REBT) on irrational attitudes about Spouse Selection in girls and boys. Therefore, 32 girls and boys in city of Bandar Abbas were randomly selected and assigned to two experimental and control groups with 16 girls and boys in each group. The experimental group received 8 sessions in each week. Attitudes about Mate Selection Scale (ARMSS) were used as the pretest and post-test. Results of analysis of covariate showed that the mean scores of irrational attitudes about romance and mate selection in the experimental group was significantly lower than the control group in the post test (p= 0/001). Also, mean scores of subscales of irrational attitudes about romance and mate selection (believe love, pivotal experience, idealization, opposite seeking, easy getting and optimistic view) in experimental group was significantly lower than control group in the post test

Effectiveness of Education of Self-esteem Behavior-Cognition Approach on High School Male Students’ Aggression in Shahre-Kurd

This study was conducted in order to examine effectiveness of educating self-esteem behavior-cognition approach on students’ aggression. The methodology was experimental research with pre-test and post-test for control group. Statistical population included all high school male stu-dents in Share-Kurd. The sample was 30 students whom were selected among 100 students answering aggression questionnaire, their scores were one standard deviation lower than mean and these 30 students were randomly categorized in two 15-person experimental and control groups. Experimental group attended in 8 sessions of self-esteem behavior-cognition education, 1.5 hour per week while control group did not receive any educational courses. Research tools included Coopersmith self-esteem questionnaire, Buss and Perri aggression questionnaire and after data collection, covariance analysis was used in addition to descriptive statistics methods for data analysis. Data analysis shows that self-esteem behavior-cognition education in (P<0/05) causes reduction of teens’ aggression.

A goal-based approach for qualification of new technologies: Foundations, tool support, and industrial validation

New technologies typically involve innovative aspects that are not addressed by the existing normative standards and hence are not assessable through common certification procedures. To ensure that new technologies can be implemented in a safe and reliable manner, a specific kind of assessment is performed, which in many industries, e.g., the energy sector, is known as Technology Qualification (TQ). TQ aims at demonstrating with an acceptable level of confidence that a new technology will function within specified limits. Expert opinion plays an important role in TQ, both to identify the safety and reliability evidence that needs to be developed and to interpret the evidence provided. Since there are often multiple experts involved in TQ, it is crucial to apply a structured process for eliciting expert opinions, and to use this information systematically when analyzing the satisfaction of the technology's safety and reliability objectives. In this paper, we present a goal-based approach for TQ. Our approach enables analysts to quantitatively reason about the satisfaction of the technology's overall goals and further to identify the aspects that must be improved to increase goal satisfaction. The approach is founded on three main components: goal models, expert elicitation, and probabilistic simulation. We describe a tool, named Modus, that we have developed in support of our approach. We provide an extensive empirical validation of our approach through two industrial case studies and a survey. © 2013 Elsevier Ltd

A SysML-based approach to traceability management and design slicing in support of safety certification: Framework, tool support, and case studies

Context: Traceability is one of the basic tenets of all safety standards and a key prerequisite for software safety certification. In the current state of practice, there is often a significant traceability gap between safety requirements and software design. Poor traceability, in addition to being a non-compliance issue on its own, makes it difficult to determine whether the design fulfills the safety requirements, mainly because the design aspects related to safety cannot be clearly identified. Objective: The goal of this article is to develop a framework for specifying and automatically extracting design aspects relevant to safety requirements. This goal is realized through the combination of two components: (1) A methodology for establishing traceability between safety requirements and design, and (2) an algorithm that can extract for any given safety requirement a minimized fragment (slice) of the design that is sound, and yet easy to understand and inspect. Method: We ground our framework on System Modeling Language (SysML). The framework includes a traceability information model, a methodology to establish traceability, and mechanisms for model slicing based on the recorded traceability information. The framework is implemented in a tool, named SafeSlice. Results: We prove that our slicing algorithm is sound for temporal safety properties, and argue about the completeness of slices based on our practical experience. We report on the lessons learned from applying our approach to two case studies, one benchmark and one industrial case. Both studies indicate that our approach substantially reduces the amount of information that needs to be inspected for ensuring that a given (behavioral) safety requirement is met by the design. © 2012 Elsevier B.V. All rights reserved

Nanoclay Effect on the Flow and Thermal Properties of PP/SEBS-g-MA Blend

The effect of nanoclay (Cloisite® 15A) was studied in relation to the flow behavior, mechanical and thermal properties of polypropylene/maleic anhydride-g-(styrene-ethylene-butylene-styrene) triblock copolymer (PP/SEBS(15%)-g-MA) blend. In this regard, the composites based on the blend and various amounts of nanoclay (1,3,5 wt%) were melt compounded using an internal mixer at the temperature of 190°C, rotor speed of 75rpm for 12min. The prepared samples were compression molded in a hot-press machine under the conditions of 190°C, 31 MPa pressure for 9 min to obtain the sheets in various thicknesses. The sheets were then cooled to ambient temperature with cooling water at the rate of 1.5°C.s-1. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to study the structure and morphology of the samples. In addition, the mechanical and thermal properties were determined by standard methods. The results of X-ray diffraction and transmission electron photographs confirmed both exfoliated and intercalated structures in the prepared samples. There were balanced strength/toughness properties in all the prepared nanocomposites by addition of both SEBS-g-MA and clay simultaneously. The measurement of rheological properties showed that as the shear rate increased, the apparent viscosity of the samples decreased (shear thinning behavior). Gradual increase in incorporation of nanoclay also decreased the melt flow index (MFI) values. In addition, increases in nanoclay content had an insignificant effect on the thermal behavior and in that respect there were slight increases in degree of crystallinity, heat deflection temperature (HDT) as well as Vicat softening point by slight increase in temperatureThe effect of nanoclay (Cloisite® 15A) was studied in relation to the flow behavior, mechanical and thermal properties of polypropylene/maleic anhydride-g-(styrene-ethylene-butylene-styrene) triblock copolymer (PP/SEBS(15%)-g-MA) blend. In this regard, the composites based on the blend and various amounts of nanoclay (1,3,5 wt%) were melt compounded using an internal mixer at the temperature of 190°C, rotor speed of 75rpm for 12min. The prepared samples were compression molded in a hot-press machine under the conditions of 190°C, 31 MPa pressure for 9 min to obtain the sheets in various thicknesses. The sheets were then cooled to ambient temperature with cooling water at the rate of 1.5°C.s-1. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to study the structure and morphology of the samples. In addition, the mechanical and thermal properties were determined by standard methods. The results of X-ray diffraction and transmission electron photographs confirmed both exfoliated and intercalated structures in the prepared samples. There were balanced strength/toughness properties in all the prepared nanocomposites by addition of both SEBS-g-MA and clay simultaneously. The measurement of rheological properties showed that as the shear rate increased, the apparent viscosity of the samples decreased (shear thinning behavior). Gradual increase in incorporation of nanoclay also decreased the melt flow index (MFI) values. In addition, increases in nanoclay content had an insignificant effect on the thermal behavior and in that respect there were slight increases in degree of crystallinity, heat deflection temperature (HDT) as well as Vicat softening point by slight increase in temperature.The aim of this work is to study effect of nanoclay (Cloisite® 15A) on the flow behavior, mechanical and thermal properties of polypropylene/maleic anhydride grafted-(styrene-ethylene-butylene- styrene) triblock copolymer (PP/15%SEBS-g-MA) blend. In this regard, the composites based on the blend and various amounts of nanoclay (1,3,5 wt.%) were melt compounded using an internal mixer at the temperature of 190oC, rotor speed of 75rpm for 12min. The prepared samples were then compression molded in a hot-press machine under the conditions of 190°C, 31 MPa pressure, for 9 min to obtain the sheets in various thicknesses. Afterwards, the plates were cooled to ambient temperature with cooling water at the rate of 1.5oC.s-1. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to study the structure and morphology of the samples. In addition, the mechanical and thermal properties were carried out by means of the standard methods. The results of X-ray diffraction and transmission electron photographs confirm both exfoliated and intercalated structures in the prepared samples. There is balanced strength/toughness properties in all the prepared nanocomposites via addition both SEBS-g-MA and clay simultaneously. The measurement of rheological properties show that as the shear rate increases, the apparent viscosity of the samples decreases (shear thinning behavior). Incorporation of nanoclay and increasing its content also decreases the melt flow index (MFI) values. In addition, increase in the nanoclay content have the insignificant effect on the thermal behavior so that slight increase in crystallinity temperature/degree, heat deflection temperature (HDT) as well as vicat softening point are obtained

Traceability and sysml design slices to support safety inspections: A controlled experiment

Certifying safety-critical software and ensuring its safety requires checking the conformance between safety requirements and design. Increasingly, the development of safety-critical software relies on modeling, and the System Modeling Language (SysML) is now commonly used in many industry sectors. Inspecting safety conformance by comparing design models against safety requirements requires safety inspectors to browse through large models and is consequently time consuming and error-prone. An important concern in relation to traceability is cost effectiveness. Making traceability cost effective requires a careful analysis of the trade-offs between the costs incurred over establishing and maintaining traceability links and the benefits that traceability offers. Traceability is considered worthwhile if it presents a significant advantage for achieving certain goals. In our case, the goals pursued from traceability are to increase the correctness and decrease the effort associated with design safety inspections