503,930 research outputs found

    DDP-GCN: Multi-Graph Convolutional Network for Spatiotemporal Traffic Forecasting

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    Traffic speed forecasting is one of the core problems in Intelligent Transportation Systems. For a more accurate prediction, recent studies started using not only the temporal speed patterns but also the spatial information on the road network through the graph convolutional networks. Even though the road network is highly complex due to its non-Euclidean and directional characteristics, previous approaches mainly focus on modeling the spatial dependencies only with the distance. In this paper, we identify two essential spatial dependencies in traffic forecasting in addition to distance, direction and positional relationship, for designing basic graph elements as the smallest building blocks. Using the building blocks, we suggest DDP-GCN (Distance, Direction, and Positional relationship Graph Convolutional Network) to incorporate the three spatial relationships into prediction network for traffic forecasting. We evaluate the proposed model with two large-scale real-world datasets, and find 7.40% average improvement for 1-hour forecasting in highly complex urban networks

    Space Frequency Codes from Spherical Codes

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    A new design method for high rate, fully diverse ('spherical') space frequency codes for MIMO-OFDM systems is proposed, which works for arbitrary numbers of antennas and subcarriers. The construction exploits a differential geometric connection between spherical codes and space time codes. The former are well studied e.g. in the context of optimal sequence design in CDMA systems, while the latter serve as basic building blocks for space frequency codes. In addition a decoding algorithm with moderate complexity is presented. This is achieved by a lattice based construction of spherical codes, which permits lattice decoding algorithms and thus offers a substantial reduction of complexity.Comment: 5 pages. Final version for the 2005 IEEE International Symposium on Information Theor

    CEEME: compensating events based execution monitoring enforcement for Cyber-Physical Systems

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    Fundamentally, inherently observable events in Cyber-Physical Systems with tight coupling between cyber and physical components can result in a confidentiality violation. By observing how the physical elements react to cyber commands, adversaries can identify critical links in the system and force the cyber control algorithm to make erroneous decisions. Thus, there is a propensity for a breach in confidentiality leading to further attacks on availability or integrity. Due to the highly integrated nature of Cyber-Physical Systems, it is also extremely difficult to map the system semantics into a security framework under existing security models. The far-reaching objective of this research is to develop a science of selfobfuscating systems based on the composition of simple building blocks. A model of Nondeducibility composes the building blocks under Information Flow Security Properties. To this end, this work presents fundamental theories on external observability for basic regular networks and the novel concept of event compensation that can enforce Information Flow Security Properties at runtime --Abstract, page iii

    Quantum Gates and Memory using Microwave Dressed States

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    Trapped atomic ions have been successfully used for demonstrating basic elements of universal quantum information processing (QIP). Nevertheless, scaling up of these methods and techniques to achieve large scale universal QIP, or more specialized quantum simulations remains challenging. The use of easily controllable and stable microwave sources instead of complex laser systems on the other hand promises to remove obstacles to scalability. Important remaining drawbacks in this approach are the use of magnetic field sensitive states, which shorten coherence times considerably, and the requirement to create large stable magnetic field gradients. Here, we present theoretically a novel approach based on dressing magnetic field sensitive states with microwave fields which addresses both issues and permits fast quantum logic. We experimentally demonstrate basic building blocks of this scheme to show that these dressed states are long-lived and coherence times are increased by more than two orders of magnitude compared to bare magnetic field sensitive states. This changes decisively the prospect of microwave-driven ion trap QIP and offers a new route to extend coherence times for all systems that suffer from magnetic noise such as neutral atoms, NV-centres, quantum dots, or circuit-QED systems.Comment: 9 pages, 4 figure

    PERANCANGAN LAYANAN SYSTEM INFORMASI DALAM PROGRAM BIMBINGAN DAN KONSELING BERBASIS DESKTOP TINGKAT SMK

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    Counseling guidance is really needed in a school that can include data on student biodata information but it involves all important aspects such as grades, discipline, attendance, extracurricular activities, and so forth. Data management in counseling guidance is still manual, so it requires more time and more complicated processes. The use of computer application programs in managing student data can also improve school images. The use of computer application programs makes it easy for teachers to manage student data, especially in the management of counseling guidance. The Counseling Guidance Information System is intended to facilitate the Counseling Guidance teacher in registering students who have consulted. The stored data is expected to be utilized by the school in making conclusions and decisions regarding the problems and developments of students in the future. Regarding student privacy, there is a security system where not all teachers can have access to the system. The basic concept of information service systems (Hutahean, 2014) is a collection consisting of several components which are often referred to as building blocks, namely: a) input blocks, b) output blocks, c) technology blocks, d) model blocks, e ) database blocks, f) control blocks

    Materiality and emergence in environmental information systems

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    Information systems can be an integral part of environmental management practices enacted in the pursuit of environmental sustainability outcomes. We analyse the specific case of an environmental information system developed by a South Australian environmental regulator. The information system was intended to support efforts to sustain water quality by controlling the discharge of ‘greywater’ from vessels using South Australia’s inland waters. We conceptualize the information system as the outcome of a continuing, though non-deterministic, trajectory of interacting material and human agencies, in the form of technology and routines. In our analysis, we trace how these basic building blocks of the system came to be, and how they shaped the emergent environmental information system in particular ways

    Generalizing the Sampling Property of the Q-function for Error Rate Analysis of Cooperative Communication in Fading Channels

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    This paper extends some approximation methods that are used to identify closed form Bit Error Rate (BER) expressions which are frequently utilized in investigation and comparison of performance for wireless communication systems in the literature. By using this group of approximation methods, some expectation integrals, which are complicated to analyze and have high computational complexity to evaluate through Monte Carlo simulations, are computed. For these integrals, by using the sampling property of the integrand functions of one or more arguments, reliable BER expressions revealing the diversity and coding gains are derived. Although the methods we present are valid for a larger class of integration problems, in this work we show the step by step derivation of the BER expressions for a canonical cooperative communication scenario in addition to a network coded system starting from basic building blocks. The derived expressions agree with the simulation results for a very wide range of signal-to-noise ratio (SNR) values.Comment: 5 pages, 5 figures, Submitted to IEEE International Symposium on Information Theory, ISIT 2013, Istanbul, Turke
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