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The volume consists of scientifi c and research papers of the Sixth International Conference “Actual Problems of System and Software Engineering” (APSSE-2019). The Conference was held at the National Research University “Higher School of Economics” from November 12 to November 14, 2019 in Moscow, Russia. The conference was devoted to the analysis of the status, contemporary trends, research issues and practical results obtained by national and foreign scientists and experts in the system and software engineering area, as well as information and analytical systems development area using Big Data technologies. The target audience of the conference came to be the experts, students and postgraduates working in the area of ordering, designing, development, implementation, operation, and maintenance of information and analytical systems for various applications and their software, also working on custom software development. Plenary papers were delivered by the leading domestic and foreign specialists and were aimed at developing the views on the most important and fundamental aspects of the information technology development. Submitted articles were selected for publication. All the submitted articles were reviewed by the members of the Program Committee as well as by the independent reviewers.
Abstract——State identification sequences, such as homing
and distinguishing sequences (HS and DS), are widely used in FSM
(Finite State Machine) based testing in order to reduce the size of
a returned complete test suite as well as minimize checking efforts
in passive testing. Preset HS are known to always exist for
deterministic complete reduced FSMs but it is not the case for
nondeterministic FSMs. It is also known that in this case, adaptive
HS exist more often and usually are shorter than the preset.
Nowadays, a number of specifications are represented by
nondeterministic FSMs and thus, a deeper study of such sequences
is required. There exist sufficient and necessary conditions for the
existence of an adaptive HS for complete nondeterministic FSMs
when each state can be an initial state but those conditions become
only sufficient for weakly initialized FSMs where only some states
are initial. In this paper, we propose sufficient and necessary
conditions for a weakly initialized FSM to have an adaptive
homing sequence, possibly up to given length, which are based on
deriving an appropriate so-called homing FSM. The experimental
evaluation of the existence of adaptive and preset HS is performed
for randomly generated FSMs.
In the paper, we suggest new approach to schedulability problem for strict periodic tasks (a periodic task is strict if it must be started in equal intervals of time – task’s period). Given permissible tasks’ periods, our approach allows to obtain quickly all schedulable sets of tasks with such periods and to build immediately a conflict-free schedule for each obtained set. The approach is based on mathematical methods of graph theory and number theory. We illustrate the approach by a number of examples and present current practical results.
Requirements play an important role in the process of safety critical software development. To achieve reasonable quality and cost ratio a tool support for requirements management is required. The paper presents a formal definition of a metamodel that is used as a basis of Requality requirements management tool. An experience of implementation of the meta model is discussed.
Testing is one of the most frequently used techniques in practice to assure the quality and thereliability of software systems. It is used not only during the development of such systemsbut also during their operation. Over the last years, new testing technologies appeared forchecking both functional and non-functional requirements of systems. Application areas ofthese technologies include but are not limited to communicating systems such as protocols,middleware, networks, web services, cloud computing systems, wireless applications, con-trol systems, business information systems, embedded and real-time software, and softwareproduct lines.
Finite State Machine (FSM) based approaches are widely used for deriving tests with guaranteed fault coverage for discrete event systems and as the behavior of many nowadays information and control systems depends on time, classical FSMs are extended by clock variables. Moreover, optionality in the real system’s specifications motivates the studying test derivation against models with the nondeterministic behavior. In this paper, we adapt classical FSM based test derivation methods for nondeterministic FSMs with timed guards and timeouts (TFSMs). We show that unlike classical FSM conformance relation, the check cannot be reduced to checking the correspondence between TFSMs transitions and this violates the main principle of FSM based test derivation methods. Respectively, a proposed approach and the appropriate fault model are based on the FSM abstraction of the given TFSM specification that is used to adequately describe the behavior of a TFSM. The fault domain contains TFSMs with the known upper boundary on the number of FSM abstraction states and allows to avoid explicit enumeration of implementations under test. We study properties of the FSM abstraction for a nondeterministic TFSM and justify that the use of an FSM abstraction allows to adapt classical FSM based test derivation methods when deriving tests with guaranteed fault coverage for TFSMs. A method is proposed for deriving a complete test suite for a complete possibly nondeterministic TFSM when an implementation under test is a deterministic complete TFSM.
Requirements are an integral part of any software and hardware development process. The area where requirements become significantly important is the development of safety-critical systems which usage may cause risks on human lives. So the process of their development is often maintained by certification centers that requires from developers to meet the best practices supporting the safety of end product. This article reveals one possible approach to requirements management that was based on experience of embedded hardware development for civil avionics. This approach is now spread over different areas. Authors list the set of common tasks related to given approach. They also define the set of software features used to reduce the complexity of development and to mitigate risks. Authors review set of existing solutions in requirements management area using the listed features. In this article it is also defined on how given features can be applied within the given approach.
Cloud security issues are important factors for data storage and processing. Apart from the existing security and reliability problems of traditional distributed computing, there are new security and reliability problems. They include attacks on a virtual machine, attacks on the synchronization keys, and so on. According to the assessment of international experts in the field of cloud security, there are risks of cloud collusion under uncertain conditions. To mitigate this type of uncertainty and reduce harms it can cause, we propose AC-RRNS algorithm based on modified threshold Asmuth–Bloom and Mignotte secret sharing schemes. We prove that the algorithm satisfies the formal definition of computational security. If the adversary coalition knows the secret shares, but does not know the secret key, the probability to obtain the secret is less than . The probability is less than with unknown secret shares and known secret key, and with unknown secret key. Its complexity is equal to brute-force method. We demonstrate that the proposed scheme ensures security under several types of attacks. We propose approaches for selection of parameters for AC-RRNS secret sharing scheme to optimize the system behavior and data redundancy of encryption.
A top-down approach is presented for checking the existence and derivation of an adaptive distinguishing test case (called also an adaptive distinguishing sequence) for a nondeterministic finite state machine (NDFSM). When such a test case exists, the method returns a canonical test case that includes all other distinguishing tests of the given complete observable NDFSM. In the second part of the paper, a constructive approach is provided for deriving a class of complete observable NDFSMs with n states, n > 2, and 2 n − n − 1 inputs such that a shortest adaptive distinguishing test case for each NDFSM in the intended class has the length (height) 2 n − n − 1. In other words, we prove the reachability of the exponential upper bound on the length of a shortest adaptive distinguishing sequence for complete observable NDFSMs while for deterministic machines the upper bound is polynomial with respect to the number of states. For constructing the intended class of NDFSMs for a given n, we propose a special linear order over all the non-empty subsets without singletons of an n-element set. The obtained tight exponential upper bound initiates further research on identifying certain NDFSM classes where this upper bound is not reachable.
In this paper, we propose an adaptive model of data storage in a heterogeneous distributed cloud environment. Our system utilizes the methods of secret sharing schemes and error correction codes based on Redundant Residue Number System (RRNS). We consider data uploading, storing and downloading. To minimize data access, we use data transfer mechanism between cloud providers. We provide theoretical analysis and experimental evaluation of our scheme with six real data storage providers. We show how dynamic adaptive strategies not only increase security, reliability, and reduction of data redundancy but allow processing encrypted data. We also discuss potentials of this approach, and address methods for mitigating the risks of confidentiality, integrity, and availability associated with the loss of information, denial of access for a long time, and information leakage.
A component model enabling to construct new software components
from existing ones dynamically, at runtime, without their bytecodes generation is
presented with supporting it software framework. The framework is implemented
using JavaBeans component model, but is aimed to eliminate its drawback – the
inability to create user-defined components without bytecodes generation. To
construct user-defined component dynamically, a composed prototype object is
built using predefined (hardcoded and/or composed) component instances; that
prototype object can provide functionality required and can be transformed at
runtime into a new component (instantiable type) whose instances are able to
provide the same functionality, but more efficiently. The prototype object is
composed using meta-components – the framework provided components to
produce user-defined components dynamically.