Interrelation between characteristics of auroral electron invasions and auroral dissipation of radio waves

The study deals with small-scale auroral inhomogeneities of ionosphere (radio Aurora). The work is aimed at development of the bases of USW-radar diagnostics of ionospheric electrical fields and currents in the vicinity of stable auroral arcs. A concept of an apparatus nature of minimum (threshold) ionospheric parameters of the radio echo area, recorded at near-zero angles of approach from directions of about orthogonal to the direction of primary Hall drift is developed. Quantitative estimates of threshold densities of ionospheric Hall current are received which are necessary to detect a diffused radio echo signal by radar systems of STARE-type. The field of application covers organizations dealing with problems of physics of ionosphere and radio wave propagationAvailable from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio

The complexity of checking the existence and derivation of adaptive synchronizing experiments for deterministic FSMs

In this paper, we address the problem of setting a deterministic Finite State Machine (FSM) to a designated initial state. Differently from other papers, we propose to use adaptive synchronizing sequences (test cases) for this purpose and show that for weakly-connected deterministic complete reduced FSMs the problem of checking the existence of an adaptive synchronizing sequence is in P. For partial deterministic reduced FSMs the problem is PSPACE-complete

Decreasing the complexity of deriving test suites against nondeterministic finite state machines

The paper presents a Finite State Machine (FSM) based approach for deriving tests with reduced complexity, under the White Box testing assumption where all the faulty implementations are explicitly enumerated. The specification and implementation FSMs are assumed to be initialized, i.e., each possibly partial and (non-observable) nondeterministic FSM has a reliable reset. The proposed technique is illustrated by the application to a communication protocol

Column generation approaches to a robust airline crew pairing model for managing extra flights

The airline crew pairing problem (CPP) is one of the classical problems in airline operations research due to its crucial impact on the cost structure of an airline. Moreover, the complex crew regulations and the large scale of the resulting mathematical programming models have rendered it an academically interesting problem over decades. The CPP is a tactical problem, typically solved over a monthly planning horizon, with the objective of creating a set of crew pairings so that every ight in the schedule is covered, where a crew pairing refers to a sequence of ights operated by a single crew starting and ending at the same crew base. This paper discusses how an airline may hedge against a certain type of operational disruption by incorporating robustness into the pairings generated at the planning level. In particular, we address how a set of extra fights may be added into the fight schedule at the time of operation by modifying the pairings at hand and without delaying or canceling the existing fights in the schedule. We assume that the set of potential extra fights and their associated departure time windows areknown at the planning stage. We note that this study was partially motivated during our interactions with the smaller local airlines in Turkey which sometimes have to add extra fights to their schedule at short notice, e.g., charter fights. These airlines can typically estimate the potential time windows of the extra fights based on their past experiences, but prefer to ignore this information during planning since these flights may not need to be actually operated. Typically, these extra flights are then handled by recovery procedures at the time of operation which may lead to substantial deviations from the planned crew pairings and costs. The reader is referred to [3] for an in-depth discussion of the conceptual framework of this problem which we refer to as the Robust Crew Pairing for Managing Extra Flights (RCPEF). In [3], the authors introduce how an extra flight may be accommodated by modifying the existing pairings and introduce a set of integer programming models that provide natural recovery options without disrupting the existing flights. These recovery options are available at the planning stage and render operational recovery procedures that pertain to crew pairing unnecessar

Identifying the effects of modifications as data dependencies

Dependence analysis on an extended finite state machine (EFSM) representation of the requirements of a system under test has been used in model-based regression testing for regression test suite (RTS) reduction (reducing the size of a given test suite by eliminating redundancies), for RTS prioritization (ordering test cases in a given test suite for early fault detection), or for RTS selection (selecting a subset of a test suite covering the identified dependencies). These particular uses of dependence analysis are based on the definitions of various types of control and data dependencies (between transitions in an EFSM) caused by a given set of modifications on the requirements. This paper considers the existing definitions of data dependencies for capturing the effects of the modifications, gives examples of their inaccuracy and incompleteness, proposes new definitions, and proves the soundness and completeness of these new definitions. Any previous work on regression testing using definitions of data dependencies capturing the effects of modifications can benefit from the proposed definitions

Column generation approaches to a robust airline crew pairing model for managing extra flights

The airline crew pairing problem (CPP) is one of the classical problems in airline operations research due to its crucial impact on the cost structure of an airline. Moreover, the complex crew regulations and the large scale of the resulting mathematical programming models have rendered it an academically interesting problem over decades. The CPP is a tactical problem, typically solved over a monthly planning horizon, with the objective of creating a set of crew pairings so that every ight in the schedule is covered, where a crew pairing refers to a sequence of ights operated by a single crew starting and ending at the same crew base. This paper discusses how an airline may hedge against a certain type of operational disruption by incorporating robustness into the pairings generated at the planning level. In particular, we address how a set of extra fights may be added into the fight schedule at the time of operation by modifying the pairings at hand and without delaying or canceling the existing fights in the schedule. We assume that the set of potential extra fights and their associated departure time windows areknown at the planning stage. We note that this study was partially motivated during our interactions with the smaller local airlines in Turkey which sometimes have to add extra fights to their schedule at short notice, e.g., charter fights. These airlines can typically estimate the potential time windows of the extra fights based on their past experiences, but prefer to ignore this information during planning since these flights may not need to be actually operated. Typically, these extra flights are then handled by recovery procedures at the time of operation which may lead to substantial deviations from the planned crew pairings and costs. The reader is referred to [3] for an in-depth discussion of the conceptual framework of this problem which we refer to as the Robust Crew Pairing for Managing Extra Flights (RCPEF). In [3], the authors introduce how an extra flight may be accommodated by modifying the existing pairings and introduce a set of integer programming models that provide natural recovery options without disrupting the existing flights. These recovery options are available at the planning stage and render operational recovery procedures that pertain to crew pairing unnecessar

Advances in test generation for testing software and systems

Among the software quality assurance techniques, testing stands out as one of the most frequently used techniques in practice. Consequently, testing is also widely studied in research. An important aspect in testing that receives much attention is the problem of automated test generation. This introductory paper summarizes the papers selected from the 25th IFIP International Conference on Testing Software and Systems (ICTSS 2013), which all deal with this topic. The field is briefly introduced by pointing out to some of the existing survey articles and relating the selected papers in this issue to each other and to the known body of knowledge