588 research outputs found

    Deep Reinforcement Learning-Based Channel Allocation for Wireless LANs with Graph Convolutional Networks

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    Last year, IEEE 802.11 Extremely High Throughput Study Group (EHT Study Group) was established to initiate discussions on new IEEE 802.11 features. Coordinated control methods of the access points (APs) in the wireless local area networks (WLANs) are discussed in EHT Study Group. The present study proposes a deep reinforcement learning-based channel allocation scheme using graph convolutional networks (GCNs). As a deep reinforcement learning method, we use a well-known method double deep Q-network. In densely deployed WLANs, the number of the available topologies of APs is extremely high, and thus we extract the features of the topological structures based on GCNs. We apply GCNs to a contention graph where APs within their carrier sensing ranges are connected to extract the features of carrier sensing relationships. Additionally, to improve the learning speed especially in an early stage of learning, we employ a game theory-based method to collect the training data independently of the neural network model. The simulation results indicate that the proposed method can appropriately control the channels when compared to extant methods

    The Real Effects of Bank-Driven Termination of Relationships: Evidence from Loan-level Matched Data

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    We examine the effects of bank-driven terminations of bank-borrower relationships on the investments of borrowing firms by exploiting a matched dataset of Japanese banks and listed firms from 1991 to 2010. We find that while bank-driven terminations do not always affect investment, they do when the firms facing termination have difficulty in either establishing a new relationship or increasing borrowings within their existing relationship. Our findings coincide with the prediction of existing theoretical models whereby financial frictions in a matching process in credit markets play an important role in firm investment

    The Time Has Come for Banks to Say Goodbye: New Evidence on Banks' Roles and Duration Effects in Relationship Terminations

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    Using a loan-level matched sample of Japanese banks and firms, we examine what factors determine the termination of the bank-firm relationship. We find that terminations are mainly driven by bank factors, but such bank-driven terminations increase when banks' capital conditions worsen. The constraints on bank capital in the Japanese banking crisis increased terminations, implying the presence of a capital crunch. Moreover, ``flight-to-quality" behavior prevailed instead of ``evergreening" in relationship terminations because of lowly capitalized banks' motives to reduce agency costs. We also find that a longer relationship duration decreased the probability of termination substantially when Japan's banking system was stable, but such duration effects weakened when the system was fragile. Japan's banking system cultivated bank-firm relationships over many decades to lower agency costs gradually, but this system malfunctioned partially in the flight to quality, whereby many banks could not afford to maintain relationships with distressed borrowers irrespective of duration

    Termination of Bank-Firm Relationships

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    Using a matched sample of Japanese banks and firms, we examine what factors determine the termination of the bank-firm relationship. The constraints on bank capital in a Japanese banking crisis increased relationship terminations, implying the presence of a capital crunch in it. Moreover, the "flight-to-quality" behavior of bank prevailed instead of "evergreening" in relationship terminations. We also found that a longer duration of the relationship strongly decreased the probability of termination when Japan's banking system was stable. Such duration effects weakened when the system was fragile, however, the longer duration still had the intertemporal smoothing effects of loan prices

    The Real Effects of Bank-Driven Termination of Relationships: Evidence from Loan-level Matched Data

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    In this study we use a matched dataset of Japanese banks and firms to examine how bank-driven terminations of bank-borrower relationships affect the investments of the borrowers. We find that bank-driven terminations significantly decrease investment, exerting an effect that exceeds that due to credit reductions within continuing relationships. Our results also show that the unwanted effect of bank-driven terminations grows as the loan market deteriorates as a whole, which prevents firms from obtaining funding from other sources after their relationships with banks are terminated. Our findings coincide with previous literature emphasizing financial frictions in the matching process and the importance of relation-specific assets in credit markets

    The Time Has Come for Banks to Say Goodbye: New Evidence on Banks' Roles and Duration Effects in Relationship Terminations

    Get PDF
    Using a loan-level matched sample of Japanese banks and firms, we examine what factors determine the termination of the bank-firm relationship. We find that terminations are mainly driven by bank factors, but such bank-driven terminations increase when banks' capital conditions worsen. The constraints on bank capital in the Japanese banking crisis increased terminations, implying the presence of a capital crunch. Moreover, ``flight-to-quality" behavior prevailed instead of ``evergreening" in relationship terminations because of lowly capitalized banks' motives to reduce agency costs. We also find that a longer relationship duration decreased the probability of termination substantially when Japan's banking system was stable, but such duration effects weakened when the system was fragile. Japan's banking system cultivated bank-firm relationships over many decades to lower agency costs gradually, but this system malfunctioned partially in the flight to quality, whereby many banks could not afford to maintain relationships with distressed borrowers irrespective of duration

    The Real Effects of Bank-Driven Termination of Relationships: Evidence from Loan-level Matched Data

    Get PDF
    In this study we use a matched dataset of Japanese banks and firms to examine how bank-driven terminations of bank-borrower relationships affect the investments of the borrowers. We find that bank-driven terminations significantly decrease investment, exerting an effect that exceeds that due to credit reductions within continuing relationships. Our results also show that the unwanted effect of bank-driven terminations grows as the loan market deteriorates as a whole, which prevents firms from obtaining funding from other sources after their relationships with banks are terminated. Our findings coincide with previous literature emphasizing financial frictions in the matching process and the importance of relation-specific assets in credit markets

    Termination of Bank-Firm Relationships

    Get PDF
    Using a matched sample of Japanese banks and firms, we examine what factors determine the termination of the bank-firm relationship. The constraints on bank capital in a Japanese banking crisis increased relationship terminations, implying the presence of a capital crunch in it. Moreover, the "flight-to-quality" behavior of bank prevailed instead of "evergreening" in relationship terminations. We also found that a longer duration of the relationship strongly decreased the probability of termination when Japan's banking system was stable. Such duration effects weakened when the system was fragile, however, the longer duration still had the intertemporal smoothing effects of loan prices

    The Emergence of A Parallel World: The Misperception Problem for Bank Balance Sheet Risk and Lending Behavior

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    We examine the reason that there have coexisted the two opposing views on distressed banks' lending behavior in Japan's post-bubble period: the one is the stagnant lending in a capital crunch and the other is the forbearance lending to low-quality borrowers. To this end, we address the measurement problem for bank balance sheet risk. We identify the credit supply and allocation effects of bank capital in the bank loan equation specified at loan level, thereby finding that the ``parallel worlds'', or the two opposing views, emerge because the regulatory capital does not reflect the actual condition of increased risk on bank balance sheet, while the market value of capital does. By uncovering banks' engagement in patching-up of the regulatory capital in the Japan's post-bubble period, we show that lowly market capitalized banks that had difficulty in building up adequate equity capital for their risk exposure decreased the overall supply of credits. The parallels world can emerge whenever banks are allowed to overvalue assets with their discretion, as in Japan' post-bubble period
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