Игорь Бурдонов - Academia.edu (original) (raw)
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Papers by Игорь Бурдонов
Вестник Томского государственного университета. Управление, вычислительная техника и информатика, Mar 3, 2014
The paper describes the learning an unknown oriented graph by automata traversing the arcs of the... more The paper describes the learning an unknown oriented graph by automata traversing the arcs of the graph and exchanging messages. The learning completes when each arc has been traversed by at least one automaton. Section 1 discusses the problems of identification of arcs and nodes in the graph, ways of exchanging messages between automata and interaction of the automata with the graph. The arcs outgoing from the same node are considered enumerated. When traversing the graph, each automaton indicates the number of the arc outgoing from the current node. The nodes have unique identifiers. The exceptions are sinks and nodes with only one incoming arc: these nodes can have empty identifier. Automaton can recognize the identifier of the current node and the number of outgoing arcs. The automata interaction media provides message transfer from one automaton to another in a limited time. The following primitives are recognized: "send message" indicating the receiver address and "receive message from any sender". Section 2 describes the idea of the algorithm. Automata are divided into regulators and runners. Runners traverse the arcs of the graph. When in a new (yet untraversed) node, runner becomes its regulator. The node regulator controls the runners travel along the arcs outgoing from this node. The regulator of the initial node, in addition, generates new runners. During execution, the graph description is created in the cumulative memory of the regulators as a spanning tree of the already traversed part of the graph oriented form the initial node. To navigate the runners, the following message is used: "where to" from runner to regulator and response message "traverse the arc" indicating the arc number and the address of the regulator of the arc terminal node if this arc has already been traversed. Regulator sends runners either along the arcs of the tree or along untraversed arcs. After traversing an untraversed arc, runners learn the identifier of its terminal node, but it needs to know whether this node has been already traversed. To get this information, the "poll" message is sent iterating all regulators linked into a list of addresses. If the node has been traversed, the node regulator sends the response message to the runner indicating its address, and the runner resends this address to the regulator of the initial node of the traversed chord in the "finish" message. This message is also used to indicate the traversal end: the regulator of the tree arc terminal node sends "finish" to the regulator of the arc initial node if it has received "finish" along all outgoing arcs. The traversal is over when regulator of the initial node receives "finish" along all outgoing arcs. Section 3 gives the estimate of the traversal time ®(m+nD), where n is a number of nodes, m is a number of arcs, and D is the maximal number of nodes with nonempty identifiers on the graph path from the initial node. The conclusion describes possible directions of further work: learning of nondeterministic graphs, use of external memory, learning graphs of special kind.
Automatic Control and Computer Sciences, 2018
Аннотация. В работе рассматриваются задачи проверки существования и синтеза синхронизирующих и ус... more Аннотация. В работе рассматриваются задачи проверки существования и синтеза синхронизирующих и установочных последовательностей для конечных входо-выходных полуавтоматов. Соответствующие последовательности могут быть использованы при идентификации состояния проверяемой системы после подачи подходящей входной последовательности. В модели, исследуемой в работе, действия разделены на входные и выходные, однако отсутствуют выделенные явно семейства начальных и финальных состояний. В статье определяются понятия синхронизирующей и установочной последовательностей и предлагаются методы их синтеза для специального класса входо-выходных полуавтоматов, у которых в каждом состоянии определены переходы или только по входным, или только по выходным действиям; кроме того, в соответствующем графе переходов отсутствуют циклы по выходным символам. Для описанного класса входо-выходных полуавтоматов устанавливаются необходимые и достаточные условия существования синхронизирующих и установочных последовательностей и оценивается длина таких последовательностей. Выделяются подклассы полуавтоматов, для которых худшие (в основном экспоненциальные) оценки сложности не являются достижимыми.
Статья посвящена проблеме моделирования, композиции и детерминизма составных систем. Компоненты с... more Статья посвящена проблеме моделирования, композиции и детерминизма составных систем. Компоненты системы моделируются конечными автоматами с несколькими входами и выходами, а взаимодействие между ними - обменом сообщениями по симплексным каналам связи. Система описывается ориентированным графом связей, вершина которого соответствует автомату компонента, а дуга - каналу связи, соединяющему выход одного автомата с входом другого. Автоматы системы работают синхронно: на каждом такте каждый автомат выполняет один переход. Определяются ассоциативная композиция автоматов системы по графу связей и условия детерминированности системы
In this paper, we study the problem of existence check and derivation of synchronizing and homing... more In this paper, we study the problem of existence check and derivation of synchronizing and homing sequences for finite input/output automata. Corresponding sequences can be effectively used for the current state identification of a system under test / verification, after the input sequence is applied. In the model considered in the paper, the alphabet of actions is divided into disjoint sets of inputs and outputs; however, no sets of possible initial or final states are defined. We introduce the notions of homing and synchronizing sequences for a specific class of such machines for which at each state the transitions only under inputs or under outputs are defined, and the machine transition diagram does not contain cycles labeled by outputs, i.e. the language of the machine does not contain traces with infinite postfix of outputs. For such a class of input/output automata, we establish necessary and sufficient conditions for the existence of synchronizing and homing sequences and di...
The paper continues the investigations on the implementation of virtual networks on the SDN data ... more The paper continues the investigations on the implementation of virtual networks on the SDN data plane which is modeled by a graph of physical connections between network nodes. A virtual network is defined as a set of ordered host pairs (sender, receiver), and it is implemented by a set of host-host paths that uniquely determine the switch settings. The opportunities to transmit a packet are limited by the host weights (priorities): a packet can be only transmitted from a host to a host if the sender has at most the same priority as the recipient, and thus, a set of paths is permissible if its every subset connects permissible host pairs. In the paper, it is proven that differently from the case when every host pair is permissible, in the graph with priorities a permissible path implementation does not exist for every set of permissible hosts. Moreover, it is shown that is some cases when such an implementation exists, the implementation is not possible without paths with cycles wh...
Graph learning with automata is a basic task in many applications. Among such applications is for... more Graph learning with automata is a basic task in many applications. Among such applications is formal model-based verification and testing of software and hardware systems, as well as network exploration including Internet and GRID. The model of a system or a network, in the final analysis, is reduced to an oriented graph of transitions with properties to be examined. In the recent years, the size of the real-life systems and networks and, consequently, the size of their graph models continuously grows. The problems arise when the graph learning by a single automaton (computer) either requires unacceptable long time, or the graph does not fit in the single computer memory, or both. Therefore, there is a task of parallel and distributed graph learning. This task is formalized as graph learning by a set of automata. The basis for such learning is graph traversal (traversing all its arcs accessible from the initial node). Automata can be generated in the initial node, move along the arc...
The paper investigates the implementation of virtual networks on the SDN data plane which is mode... more The paper investigates the implementation of virtual networks on the SDN data plane which is modeled by a graph of physical connections between network nodes. A virtual network is defined as a set of ordered host pairs (sender, receiver), and it is implemented by a set of host-host paths that uniquely determine the switch settings. A set of paths is perfect if any subset of its paths can be loop-free implemented, i.e., can be implemented without the occurrence of an endless movement of packets in a loop, without duplicate paths, when the host receives the same packet several times, and without unintended paths when the host receives the packet that was directed to another host. For the case when the switchgraph is a complete graph, sufficient conditions for the existence of the largest perfect set of paths connecting all pairs of different hosts are established. Algorithms for constructing such a largest perfect set are proposed with the estimates of their complexity. The paper also...
Proceedings of the Institute for System Programming of the RAS, 2015
Proceedings of the Institute for System Programming of RAS, 2014
Аннотация. Статья посвящена теоретическим и практическим работам по тестированию конформности (co... more Аннотация. Статья посвящена теоретическим и практическим работам по тестированию конформности (conformance testing), которые выполнялись в ИСП РАН c 1994-го года и по настоящее время. Развитие теории конформности шло по нескольким направлением и в целом носило характер обобщения используемых семантик взаимодействия, моделей и конформностей. Необходимость такого обобщения диктовалась, прежде всего, требованиями практического тестирования. Это касается таких свойств систем как недетерминизм, частичная определённость, асинхронность, разнообразие тестовых воздействий и наблюдений над поведением реализации и т.п. При этом в центре внимания всегда находилась эффективность тестирования, определяемая как оптимизацией тестовых наборов, так и алгоритмами генерации тестов, в том числе on-fly. Мы рассматриваем основные вехи этого пути в кратком и неформальном обсуждении, уделяя внимание не деталям, а основным проблемам и способам их решения, пытаясь выявить общую тенденцию развития.
Вестник Томского государственного университета. Управление, вычислительная техника и информатика, Mar 3, 2014
The paper describes the learning an unknown oriented graph by automata traversing the arcs of the... more The paper describes the learning an unknown oriented graph by automata traversing the arcs of the graph and exchanging messages. The learning completes when each arc has been traversed by at least one automaton. Section 1 discusses the problems of identification of arcs and nodes in the graph, ways of exchanging messages between automata and interaction of the automata with the graph. The arcs outgoing from the same node are considered enumerated. When traversing the graph, each automaton indicates the number of the arc outgoing from the current node. The nodes have unique identifiers. The exceptions are sinks and nodes with only one incoming arc: these nodes can have empty identifier. Automaton can recognize the identifier of the current node and the number of outgoing arcs. The automata interaction media provides message transfer from one automaton to another in a limited time. The following primitives are recognized: "send message" indicating the receiver address and "receive message from any sender". Section 2 describes the idea of the algorithm. Automata are divided into regulators and runners. Runners traverse the arcs of the graph. When in a new (yet untraversed) node, runner becomes its regulator. The node regulator controls the runners travel along the arcs outgoing from this node. The regulator of the initial node, in addition, generates new runners. During execution, the graph description is created in the cumulative memory of the regulators as a spanning tree of the already traversed part of the graph oriented form the initial node. To navigate the runners, the following message is used: "where to" from runner to regulator and response message "traverse the arc" indicating the arc number and the address of the regulator of the arc terminal node if this arc has already been traversed. Regulator sends runners either along the arcs of the tree or along untraversed arcs. After traversing an untraversed arc, runners learn the identifier of its terminal node, but it needs to know whether this node has been already traversed. To get this information, the "poll" message is sent iterating all regulators linked into a list of addresses. If the node has been traversed, the node regulator sends the response message to the runner indicating its address, and the runner resends this address to the regulator of the initial node of the traversed chord in the "finish" message. This message is also used to indicate the traversal end: the regulator of the tree arc terminal node sends "finish" to the regulator of the arc initial node if it has received "finish" along all outgoing arcs. The traversal is over when regulator of the initial node receives "finish" along all outgoing arcs. Section 3 gives the estimate of the traversal time ®(m+nD), where n is a number of nodes, m is a number of arcs, and D is the maximal number of nodes with nonempty identifiers on the graph path from the initial node. The conclusion describes possible directions of further work: learning of nondeterministic graphs, use of external memory, learning graphs of special kind.
Automatic Control and Computer Sciences, 2018
Аннотация. В работе рассматриваются задачи проверки существования и синтеза синхронизирующих и ус... more Аннотация. В работе рассматриваются задачи проверки существования и синтеза синхронизирующих и установочных последовательностей для конечных входо-выходных полуавтоматов. Соответствующие последовательности могут быть использованы при идентификации состояния проверяемой системы после подачи подходящей входной последовательности. В модели, исследуемой в работе, действия разделены на входные и выходные, однако отсутствуют выделенные явно семейства начальных и финальных состояний. В статье определяются понятия синхронизирующей и установочной последовательностей и предлагаются методы их синтеза для специального класса входо-выходных полуавтоматов, у которых в каждом состоянии определены переходы или только по входным, или только по выходным действиям; кроме того, в соответствующем графе переходов отсутствуют циклы по выходным символам. Для описанного класса входо-выходных полуавтоматов устанавливаются необходимые и достаточные условия существования синхронизирующих и установочных последовательностей и оценивается длина таких последовательностей. Выделяются подклассы полуавтоматов, для которых худшие (в основном экспоненциальные) оценки сложности не являются достижимыми.
Статья посвящена проблеме моделирования, композиции и детерминизма составных систем. Компоненты с... more Статья посвящена проблеме моделирования, композиции и детерминизма составных систем. Компоненты системы моделируются конечными автоматами с несколькими входами и выходами, а взаимодействие между ними - обменом сообщениями по симплексным каналам связи. Система описывается ориентированным графом связей, вершина которого соответствует автомату компонента, а дуга - каналу связи, соединяющему выход одного автомата с входом другого. Автоматы системы работают синхронно: на каждом такте каждый автомат выполняет один переход. Определяются ассоциативная композиция автоматов системы по графу связей и условия детерминированности системы
In this paper, we study the problem of existence check and derivation of synchronizing and homing... more In this paper, we study the problem of existence check and derivation of synchronizing and homing sequences for finite input/output automata. Corresponding sequences can be effectively used for the current state identification of a system under test / verification, after the input sequence is applied. In the model considered in the paper, the alphabet of actions is divided into disjoint sets of inputs and outputs; however, no sets of possible initial or final states are defined. We introduce the notions of homing and synchronizing sequences for a specific class of such machines for which at each state the transitions only under inputs or under outputs are defined, and the machine transition diagram does not contain cycles labeled by outputs, i.e. the language of the machine does not contain traces with infinite postfix of outputs. For such a class of input/output automata, we establish necessary and sufficient conditions for the existence of synchronizing and homing sequences and di...
The paper continues the investigations on the implementation of virtual networks on the SDN data ... more The paper continues the investigations on the implementation of virtual networks on the SDN data plane which is modeled by a graph of physical connections between network nodes. A virtual network is defined as a set of ordered host pairs (sender, receiver), and it is implemented by a set of host-host paths that uniquely determine the switch settings. The opportunities to transmit a packet are limited by the host weights (priorities): a packet can be only transmitted from a host to a host if the sender has at most the same priority as the recipient, and thus, a set of paths is permissible if its every subset connects permissible host pairs. In the paper, it is proven that differently from the case when every host pair is permissible, in the graph with priorities a permissible path implementation does not exist for every set of permissible hosts. Moreover, it is shown that is some cases when such an implementation exists, the implementation is not possible without paths with cycles wh...
Graph learning with automata is a basic task in many applications. Among such applications is for... more Graph learning with automata is a basic task in many applications. Among such applications is formal model-based verification and testing of software and hardware systems, as well as network exploration including Internet and GRID. The model of a system or a network, in the final analysis, is reduced to an oriented graph of transitions with properties to be examined. In the recent years, the size of the real-life systems and networks and, consequently, the size of their graph models continuously grows. The problems arise when the graph learning by a single automaton (computer) either requires unacceptable long time, or the graph does not fit in the single computer memory, or both. Therefore, there is a task of parallel and distributed graph learning. This task is formalized as graph learning by a set of automata. The basis for such learning is graph traversal (traversing all its arcs accessible from the initial node). Automata can be generated in the initial node, move along the arc...
The paper investigates the implementation of virtual networks on the SDN data plane which is mode... more The paper investigates the implementation of virtual networks on the SDN data plane which is modeled by a graph of physical connections between network nodes. A virtual network is defined as a set of ordered host pairs (sender, receiver), and it is implemented by a set of host-host paths that uniquely determine the switch settings. A set of paths is perfect if any subset of its paths can be loop-free implemented, i.e., can be implemented without the occurrence of an endless movement of packets in a loop, without duplicate paths, when the host receives the same packet several times, and without unintended paths when the host receives the packet that was directed to another host. For the case when the switchgraph is a complete graph, sufficient conditions for the existence of the largest perfect set of paths connecting all pairs of different hosts are established. Algorithms for constructing such a largest perfect set are proposed with the estimates of their complexity. The paper also...
Proceedings of the Institute for System Programming of the RAS, 2015
Proceedings of the Institute for System Programming of RAS, 2014
Аннотация. Статья посвящена теоретическим и практическим работам по тестированию конформности (co... more Аннотация. Статья посвящена теоретическим и практическим работам по тестированию конформности (conformance testing), которые выполнялись в ИСП РАН c 1994-го года и по настоящее время. Развитие теории конформности шло по нескольким направлением и в целом носило характер обобщения используемых семантик взаимодействия, моделей и конформностей. Необходимость такого обобщения диктовалась, прежде всего, требованиями практического тестирования. Это касается таких свойств систем как недетерминизм, частичная определённость, асинхронность, разнообразие тестовых воздействий и наблюдений над поведением реализации и т.п. При этом в центре внимания всегда находилась эффективность тестирования, определяемая как оптимизацией тестовых наборов, так и алгоритмами генерации тестов, в том числе on-fly. Мы рассматриваем основные вехи этого пути в кратком и неформальном обсуждении, уделяя внимание не деталям, а основным проблемам и способам их решения, пытаясь выявить общую тенденцию развития.