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Proceedings of the 2017 Ivannikov ISPRAS Open Conference
Information and software systems almost never stabilize after the release. They change, among other reasons, due to difficulties of implementation, bug repairs, and environmental shifts. Thus, their behavior differs from models, which were used at the design stage. Process owner usually wants relevant, up-to-date models. Fortunately, most modern information systems write detailed event logs of their functioning. In this paper, we describe an algorithm of non-local process correction, that employs the two fundamental algorithmic paradigms: “divide and conquer” and “greedy processing”. It decomposes the process model and repairs sub-models in a greedy way using event logs with actual behavior. Using this procedure, it is possible to correct both local and non-local inconsistencies. The paper considers the algorithm and the results of its experimental evaluation using several artificial examples.
Embedded devices may be significantly constrained in main memory, storage and CPU loads they can accommodate. The smaller the program, the faster it is loaded into memory. The smaller the system image, the cheaper can be production of the device. There are two ways to approach system image minification. The first way is to carefully write software adding no unnecessary parts from the start. The second way is to use existing software with unnecessary parts removed. In this work we implement the latter approach. Our work is concerned with eliminating unused code and data from dynamically linked programs; for statically linked programs, simple linker analysis is sufficient and has already been implemented.
Embedded devices may be significantly constrained in main memory, storage and CPU loads they can accommodate. The smaller the program, the faster it is loaded into memory. The smaller the system image, the cheaper can be production of the device. There are two ways to approach system image minification. The first way is to carefully write software adding no unnecessary parts from the start. The second way is to use existing software with unnecessary parts removed. In this work we implement the latter approach. Our work is concerned with eliminating unused code and data from dynamically linked programs; for statically linked programs, simple linker analysis is sufficient and has already been implemented.
A model for organizing cargo transportation between two node stations connected by a railway line which contains a certain number of intermediate stations is considered. The movement of cargo is in one direction. Such a situation may occur, for example, if one of the node stations is located in a region which produce raw material for manufacturing industry located in another region, and there is another node station. The organization of freight traffic is performed by means of a number of technologies. These technologies determine the rules for taking on cargo at the initial node station, the rules of interaction between neighboring stations, as well as the rule of distribution of cargo to the final node stations. The process of cargo transportation is followed by the set rule of control. For such a model, one must determine possible modes of cargo transportation and describe their properties. This model is described by a finite-dimensional system of differential equations with nonlocal linear restrictions. The class of the solution satisfying nonlocal linear restrictions is extremely narrow. It results in the need for the “correct” extension of solutions of a system of differential equations to a class of quasi-solutions having the distinctive feature of gaps in a countable number of points. It was possible numerically using the Runge–Kutta method of the fourth order to build these quasi-solutions and determine their rate of growth. Let us note that in the technical plan the main complexity consisted in obtaining quasi-solutions satisfying the nonlocal linear restrictions. Furthermore, we investigated the dependence of quasi-solutions and, in particular, sizes of gaps (jumps) of solutions on a number of parameters of the model characterizing a rule of control, technologies for transportation of cargo and intensity of giving of cargo on a node station.
Event logs collected by modern information and technical systems usually contain enough data for automated process models discovery. A variety of algorithms was developed for process models discovery, conformance checking, log to model alignment, comparison of process models, etc., nevertheless a quick analysis of ad-hoc selected parts of a journal still have not get a full-fledged implementation. This paper describes an ROLAP-based method of multidimensional event logs storage for process mining. The result of the analysis of the journal is visualized as directed graph representing the union of all possible event sequences, ranked by their occurrence probability. Our implementation allows the analyst to discover process models for sublogs defined by ad-hoc selection of criteria and value of occurrence probability
The geographic information system (GIS) is based on the first and only Russian Imperial Census of 1897 and the First All-Union Census of the Soviet Union of 1926. The GIS features vector data (shapefiles) of allprovinces of the two states. For the 1897 census, there is information about linguistic, religious, and social estate groups. The part based on the 1926 census features nationality. Both shapefiles include information on gender, rural and urban population. The GIS allows for producing any necessary maps for individual studies of the period which require the administrative boundaries and demographic information.
Existing approaches suggest that IT strategy should be a reflection of business strategy. However, actually organisations do not often follow business strategy even if it is formally declared. In these conditions, IT strategy can be viewed not as a plan, but as an organisational shared view on the role of information systems. This approach generally reflects only a top-down perspective of IT strategy. So, it can be supplemented by a strategic behaviour pattern (i.e., more or less standard response to a changes that is formed as result of previous experience) to implement bottom-up approach. Two components that can help to establish effective reaction regarding new initiatives in IT are proposed here: model of IT-related decision making, and efficiency measurement metric to estimate maturity of business processes and appropriate IT. Usage of proposed tools is demonstrated in practical cases.
Let G be a semisimple algebraic group whose decomposition into the product of simple components does not contain simple groups of type A, and P⊆G be a parabolic subgroup. Extending the results of Popov [7], we enumerate all triples (G, P, n) such that (a) there exists an open G-orbit on the multiple flag variety G/P × G/P × . . . × G/P (n factors), (b) the number of G-orbits on the multiple flag variety is finite.
I give the explicit formula for the (set-theoretical) system of Resultants of m+1 homogeneous polynomials in n+1 variables