169 research outputs found

    Grouping Based Blind Interference Alignment for KK-user MISO Interference Channels

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    We propose a blind interference alignment (BIA) through staggered antenna switching scheme with no ideal channel assumption. Contrary to the ideal assumption that channels remain constant during BIA symbol extension period, when the coherence time of the channel is relatively short, channel coefficients may change during a given symbol extension period. To perform BIA perfectly with realistic channel assumption, we propose a grouping based supersymbol structure for KK-user interference channels which can adjust a supersymbol length to given coherence time. It is proved that the supersymbol length could be reduced significantly by an appropriate grouping. Furthermore, it is also shown that the grouping based supersymbol achieves higher degrees of freedom than the conventional method with given coherence time.Comment: 5 pages, 3 figures, to appear in IEEE ISIT 201

    Interference Alignment with Limited Feedback on Two-cell Interfering Two-User MIMO-MAC

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    In this paper, we consider a two-cell interfering two-user multiple-input multiple-output multiple access channel (MIMO-MAC) with limited feedback. We first investigate the multiplexing gain of such channel when users have perfect channel state information at transmitter (CSIT) by exploiting an interference alignment scheme. In addition, we propose a feedback framework for the interference alignment in the limited feedback system. On the basis of the proposed feedback framework, we analyze the rate gap loss and it is shown that in order to keep the same multiplexing gain with the case of perfect CSIT, the number of feedback bits per receiver scales as B(M ⁣1 ⁣) ⁣log2(SNR)+CB \geq (M\!-1\!)\!\log_{2}(\textsf{SNR})+C, where MM and CC denote the number of transmit antennas and a constant, respectively. Throughout the simulation results, it is shown that the sum-rate performance coincides with the derived results.Comment: 6 pages, 2 figures, Submitted ICC 201

    A rare event classification in the advanced manufacturing system: focused on imbalanced datasets

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    In many industrial applications, classification tasks are often associated with imbalanced class labels in training datasets. Imbalanced datasets can severely affect the accuracy of class predictions, and thus they need to be handled by appropriate data processing before analyzing the data since most machine learning techniques assume that the input data is balanced. When this imbalance problem comes with highdimensional space, feature extraction can be applied. In Chapter 2, we present two versions of feature extraction techniques called CL-LNN and RD-LNN in a time series dataset based on the nearest neighbor combined with machine learning algorithms to detect a failure of the paper manufacturing machinery earlier than its occurrence from the multi-stream system monitoring data. The nearest neighbor is applied to each separate feature instead of the whole 61 features to address the curse of dimensionality. Also, another technique for the skewness between class labels can be solved by either oversampling minorities or downsampling majorities in class. In the chapter 3, we are seeking to find a better way of downsampling by selecting the most informative samples in the given imbalanced dataset through the active learning strategy to mitigate the effect of imbalanced class labels. The data selection for downsampling is performed by the criterion used in optimal experimental designs, from which the generalization error of the trained model is minimized in a sequential manner under the penalized logistic regression as a classification model. We also suggest that the performance is significantly improved, especially with the highly imbalanced dataset, e.g., the imbalanced ratio is greater than ten if tuning hyper-parameter and costweight method are applied to the active downsampling technique. The research is further extended to cover nonlinearity using nonparametric logistic regression, and performance-based active learning (PBAL) is proposed to enhance the performance compared to the existing ones such as D-optimality and A-optimality.Includes bibliographical references

    Retrospective Interference Alignment for Two-Cell Uplink MIMO Cellular Networks with Delayed CSIT

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    In this paper, we propose a new retrospective interference alignment for two-cell multiple-input multiple-output (MIMO) interfering multiple access channels (IMAC) with the delayed channel state information at the transmitters (CSIT). It is shown that having delayed CSIT can strictly increase the sum-DoF compared to the case of no CSIT. The key idea is to align multiple interfering signals from adjacent cells onto a small dimensional subspace over time by fully exploiting the previously received signals as side information with outdated CSIT in a distributed manner. Remarkably, we show that the retrospective interference alignment can achieve the optimal sum-DoF in the context of two-cell two-user scenario by providing a new outer bound.Comment: 7 pages, 2 figures, to appear in IEEE ICC 201

    Interference Alignment Through User Cooperation for Two-cell MIMO Interfering Broadcast Channels

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    This paper focuses on two-cell multiple-input multiple-output (MIMO) Gaussian interfering broadcast channels (MIMO-IFBC) with KK cooperating users on the cell-boundary of each BS. It corresponds to a downlink scenario for cellular networks with two base stations (BSs), and KK users equipped with Wi-Fi interfaces enabling to cooperate among users on a peer-to-peer basis. In this scenario, we propose a novel interference alignment (IA) technique exploiting user cooperation. Our proposed algorithm obtains the achievable degrees of freedom (DoF) of 2K when each BS and user have M=K+1M=K+1 transmit antennas and N=KN=K receive antennas, respectively. Furthermore, the algorithm requires only a small amount of channel feedback information with the aid of the user cooperation channels. The simulations demonstrate that not only are the analytical results valid, but the achievable DoF of our proposed algorithm also outperforms those of conventional techniques.Comment: This paper will appear in IEEE GLOBECOM 201

    ‘For in the day that you eat of it, you shall surely die’. The early reception history of the death warning in Genesis 2:17

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    This thesis examines the early Jewish reception of the divine prohibitive command (Gen 2:16-17) in relation to its interpretative association with the introduction of physical death to humanity. The long-time rationale has been that the eating of the tree of the knowledge of good and evil brought sin and death ‘for in the day that you eat of it, you shall surely die’ (Gen 2:17). The thesis begins by examining the meaning of Gen 2:17 in its original context, then tracing its interpretation in subsequent Second Temple Jewish Literature. The study examines the Greek translation of Gen 2:16-17 and its translational elements that expand the possible range of understanding of the prohibition that would not have originated from the Hebrew text of Genesis. The thesis continues with an exegetical analysis of allusions and references to the prohibitive command in the Dead Sea Scrolls, the Book of Ben Sira, 1 Corinthians and Romans. It is argued, firstly, that there are no explicit narrative clues in the HB as to the physical status of Adam and Eve either as immortal or mortal before their disobedience to God’s command in Gen 2:17, and that the death warning itself does not provide textual support for the understanding of the death warning in the sense of becoming mortal. It is also argued that Paul’s explicit attribution of death to the disobedience of Adam and Eve (1 Cor 15:21-22; Rom 5:12) finds its earlier traces in the course of interpretation of the aforementioned literature: 1) clarification of the meaning of the death warning, i.e. death in the sense of becoming ‘mortal’ and death due to the violation of the command as applicable not only to Adam, but also to Eve and other human beings; 2) reinforcement of the presumptive association between the death warning and the introduction of death to humanity

    A study on the relationships between playfulness, physical self-efficacy, and school happiness among middle school students participating in “0th-period physical education class” in South Korea

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    The purpose of this study is to create a scientific basis for the establishment of “0th-period physical education class” activities in schools in the future, with the expectation that the associations of morning exercise can be activated in the Korean educational community. To achieve this goal, the present study aimed to determine the relationship between the playfulness experienced during the early morning exercise of middle school students and their physical self-efficacy and education for happiness. To examine the model, questionnaires were collected from 296 middle school students located in Seoul and Gyeonggi-do, South Korea. Correlation analysis and standard multiple regression analysis were performed to analyze the data using the SPSS 21.0. The findings were as follows: First, the playfulness of the middle school “0th-period physical education class” had a significant effect on physical self-efficacy. Second, playfulness had a significant effect on education for happiness. Thirdly, physical self-efficacy was found to have a significant effect on education for happiness. Based on the results of this study, we suggest that a “0th-period physical education class” with various activities should be held during the legally required time in South Korea
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