Search results for "control flow"
showing 8 items of 8 documents
Data Quality Model-based Testing of Information Systems
2020
This paper proposes a model-based testing approach by offering to use the data quality model (DQ-model) instead of the program’s control flow graph as a testing model. The DQ-model contains definitions and conditions for data objects to consider the data object as correct. The study proposes to automatically generate a complete test set (CTS) using a DQmodel that allows all data quality conditions to be tested, resulting in a full coverage of DQ-model. In addition, the possibility to check the conformity of the data to be entered and already stored in the database is ensured. The proposed alternative approach changes the testing process: (1) CTS can be generated prior to software developmen…
Supporting Impact Analysis by Program Dependence Graph Based Forward Slicing
2007
Since software must evolve to meet the typically changing requirements, source code modifications can not be avoided. Impact analysis is one of the central and relatively demanding tasks of software maintenance. It is constantly needed while aiming at ensuring the correctness of the made modifications. Due to its importance and challenging nature automated support techniques are required. Theoretically, forward slicing is a very suitable technique for that purpose. Therefore, we have implemented a program dependence graph (PDG) based tool, called GRACE, for it. For example, due to the typical rewritings of Visual Basic programs there is a great need to support their impact analysis. However…
Nanovised Control Flow Attestation
2022
This paper presents an improvement of control flow attestation (C-FLAT) for Linux. C-FLAT is a control attestation system for embedded devices. It was implemented as a software executing in ARM’s TrustZone on bare-metal devices. We extend the design and implementation of C-FLAT through the use of a type 2 Nanovisor in the Linux operating system. We call our improved system “C-FLAT Linux”. Compared to the original C-FLAT, C-FLAT Linux reduces processing overheads and is able to detect the SlowLoris attack. We describe the architecture of C-FLAT Linux and provide extensive measurements of its performance in benchmarks and real-world scenarios. In addition, we demonstrate the…
The heterogeneity of inter-domain Internet application flows: entropic analysis and flow graph modelling
2013
The growing popularity of the Internet has triggered the proliferation of various applications, which possess diverse communication patterns and user behaviour. In this paper, the heterogeneous characteristics of Internet applications and traffic are investigated from a complex network and entropic perspective. On the basis of real-life flow data collected from a public network provided by an Internet service provider, flow graphs are constructed for five types of applications as follows: Web, P2P Download, P2P Stream, Video Stream and Instant Messaging. Three types of entropy measures are introduced to the flow graphs, and the heterogeneity of applications within a 24-h period is analysed …
Control flow strategy in a receiver coil for nuclear magnetic resonance for imaging
2020
A mathematical discussion is introduced to describe the receiver coil characterizing a nuclear magnetic resonance for imaging, starting from a general shape of the conductor. A set of different inductance calculations have been introduced, varying the shape of the conductor. The inductance calculation led to a general expression of the magnetic field of a single coil characterized by a rectangular shape. A dynamic model of the receiver coil has been developed to represent the natural frequencies that characterize the operational bandwidth. A nonstationary control strategy is implemented to make a real time changing of the operational bandwidth. The frequency response of the coil generates …
Comparing the Control-Flow of EPC and Petri Net from the End-User Perspective
2005
This contribution describes the results of a laboratory experiment which compares the Event-driven Process Chain (EPC) and Petri net (C/E net) regarding their approaches to represent the control-flow of processes. The outcome of the experiment indicates that from end-user perspective the EPC approach of applying connectors is superior to the token game. However, the non-local semantic of the EPC OR-connector clearly had a negative impact on end-user comprehension. The experiment also illustrates that the perceived ease-of-use and the intention to use the EPC notation is higher than C/E net.
Control Flow Error Checking with ISIS
2005
The Interleaved Signature Instruction Stream (ISIS) is a signature embedding technique that allows signatures to co-exist with the main processor instruction stream with a minimal impact on processor performance, without sacrificing error detection coverage or latency. While ISIS incorporate some novel error detection mechanisms to assess the integrity of the program executed by the main processor, the limited number of bits available in the signature control word question if the detection mechanisms are effective detecting errors in the program execution flow. Increasing the signature size would negatively impact the memory requirements, so this option has been rejected. The effectiveness …
Symbolic Worst Case Execution Times
2011
In immediate or hard real-time systems the correctness of an operation depends not only upon its logical correctness, but also on the time in which it is computed. In such systems, it is imperative that operations are performed within a given deadline because missing this deadline constitutes the failure of the complete system. Such systems include medical systems, flight control systems and other systems whose failure in responding punctually results in a high economical loss or even in the loss of human lives. These systems are usually analyzed in a sequence of steps in which first, a socalled control flow graph (CFG) is constructed that represents possible program flows. Furthermore, bou…