Multiple Access Communications. 5th International Workshop, MACOM 2012, Maynooth, Ireland, November 19-20, 2012. Proceeding
This book constitutes the refereed proceedings of the 5th International Workshop on Multiple Access Communications, MACOM 2012, held in Maynooth, Ireland, in November 2012. The 13 full papers and 5 demo and poster papers presented were carefully reviewed and selected from various submissions. The papers are organized in topical sections on network coding, handling interference and localization techniques at PHY/MAC layers, wireless access networks, and medium access control.
Network coding is a paradigm in data transport that allows a network node to code information flows before forwarding them. While it has been theoretically proven that network coding saves bandwidth and increases throughput of multicast communication, it does not directly consider the quality of service (QoS) requirements of multicast routing. In this paper, we study the problem of establishing minimum-cost, multiple multicast sessions over coded packet networks to meet the statistical QoS target considering boundedend-to-end statistical delay and jitter from source to each destination. For this purpose, we first propose a path-based formulation for the problem and prove that this problem is NP-hard. Then, in order to obtain an exact solution, we present an effective and efficient decomposition approach in which the problem is decomposed in to master problem and subproblems, and the solution is built up successively by feasible path generation.Computational results on random networks show that the proposed method provides an efficient way for solving the problem, even for relatively large networks.
Various networking protocols currently used in wireless networks disseminate much control information. In particular, the deterministic channel access protocol (called MCCA) specified in the IEEE 802.11 standard sends information about channel reservations. The standard proposes a novel approach to reduce this overhead, which is based on dividing various pieces of control information into several groups. When the content of some group changes, the station sends a differential update related to this group. However, a group management algorithm (GMA) - which directly affects the performance of such an approach - is not specified in the standard. Previous studies propose a simple GMA which is based on the idea to use as low number of groups as possible. However, when the content of groups changes very fast, the overhead is high. In this paper, we propose and study an enhanced GMA which manyfold reduces the overhead. We develop an analytical model to evaluate the proposed GMA performance and to find its optimal parameters. We also obtain an explicit formula for the optimal parameters in the asymptotic case. We show that such asymptotically optimal parameters, which do not depend on traffic parameters, provide low overhead in non-asymptotic case as well. Thus, the proposed GMA can be easily implemented without any complex method for parameters adjustment
This research provides the strategy of using two modern directions such as Big Data and Internet of Things and their various opportunities. There are the overview and analysis of tools which helps to work in this area: cloud services for data’s storage and its monitoring. The new using option, linking technologies Big Data and Internet of Things, is represented in this work.
The volume contains proceedings of the XIII International symposium on problems of redundancy in information and control systems.
In what follows an order-statistics based single user reception in a communication system operating under multiuser interference is considered. This paper deals with the problem of finding channel capacity of the channel corresponding to the system under consideration.
This paper addresses the problem of constructing a multiple access sys- tem for a disjunctive vector channel, similar to multiuser channel without intensity information, as described in Chang S.C., Wolf J.K. On the T-User M-Frequency Noiseless Multiple-Access Channels with and without Intensity Information // IEEE Trans. Inform. Theory. 1981. V. 27. No 1. P. 41-48.. To solve this problem a signal-code construction based on the q-ary codes is proposed. It is shown that the proposed signal-code con- struction allows to obtain the asymptotic value of the total relative rate arbitrarily close to ln 2.
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.