3,845 research outputs found

    The value of relationship banking during financial crises : evidence from the Republic of Korea

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    A systemic financial crisis with monetary restriction is probably the most promising occasion for assessing whether, and to what extent, relationship banking is valuable to borrowers. The authors take this question to a unique database of credit bureau, microeconomic information covering the pervasive financial crisis the Republic of Korea experienced in 1997-98. The database includes all corporate borrowers surveyed by the Korean Credit Bureau, providing details on the structure of their borrowings, and on their relationship with lending banks. The authors did not have access to the identity of the corporate borrower, and their only non-financial control variable was the borrower's Standard Industrial Classification (SIC). This restriction limited their analysis to smaller borrowers, keeping their sample focused on small, and medium-size enterprises, which were likely to rely on banks for external financing. Their findings: 1) Outstanding loans plunge more for firms with weaker pre-crisis relationship banking. 2) The drop in credit lines - arguably a proxy identifying shifts in the loan supply - is larger for firms relying less on strong relationship banking. 3) More intense pre-crisis relationship banking reduces the probability that a previously non-delinquent firm would build (increase) its loans in arrears in 1998, the year of the sharpest liquidity constraints. 4) All things equal, this probability depends on whether firms were borrowing from one (or more) of the five banks foreclosed in June 1998, showing that it might be particularly difficult for borrowers to replace distressed lending banks during a financial crisis. The authors'findings support the hypothesis that relationship banking = with surviving banks - has a positive value during a systemic financial crisis. They argue that for many viable small, and medium-size businesses in Korea, relationship banking reduced liquidity constraints, and thus, diminished the probability of unwarranted bankruptcy.Financial Intermediation,Banks&Banking Reform,Financial Crisis Management&Restructuring,Economic Adjustment and Lending,Housing Finance

    FCFGS-CV-Based Channel Estimation for Wideband MmWave Massive MIMO Systems with Low-Resolution ADCs

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    In this paper, the fully corrective forward greedy selection-cross validation-based (FCFGS-CV-based) channel estimator is proposed for wideband millimeter wave (mmWave) massive multiple-input multiple-output (MIMO) systems with low-resolution analog-to-digital converters (ADCs). The sparse nature of the mmWave virtual channel in the angular and delay domains is exploited to convert the maximum a posteriori (MAP) channel estimation problem to an optimization problem with a concave objective function and sparsity constraint. The FCFGS algorithm, which is the generalized orthogonal matching pursuit (OMP) algorithm, is used to solve the sparsity-constrained optimization problem. Furthermore, the CV technique is adopted to determine the proper termination condition by detecting overfitting when the sparsity level is unknown.Comment: to appear in IEEE Wireless Communications Letter

    Gradient Pursuit-Based Channel Estimation for MmWave Massive MIMO Systems with One-Bit ADCs

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    In this paper, channel estimation for millimeter wave (mmWave) massive multiple-input multiple-output (MIMO) systems with one-bit analog-to-digital converters (ADCs) is considered. In the mmWave band, the number of propagation paths is small, which results in sparse virtual channels. To estimate sparse virtual channels based on the maximum a posteriori (MAP) criterion, sparsity-constrained optimization comes into play. In general, optimizing objective functions with sparsity constraints is NP-hard because of their combinatorial complexity. Furthermore, the coarse quantization of one-bit ADCs makes channel estimation a challenging task. In the field of compressed sensing (CS), the gradient support pursuit (GraSP) and gradient hard thresholding pursuit (GraHTP) algorithms were proposed to approximately solve sparsity-constrained optimization problems iteratively by pursuing the gradient of the objective function via hard thresholding. The accuracy guarantee of these algorithms, however, breaks down when the objective function is ill-conditioned, which frequently occurs in the mmWave band. To prevent the breakdown of gradient pursuit-based algorithms, the band maximum selecting (BMS) technique, which is a hard thresholder selecting only the "band maxima," is applied to GraSP and GraHTP to propose the BMSGraSP and BMSGraHTP algorithms in this paper.Comment: to appear in PIMRC 2019, Istanbul, Turke

    Transient receptor potential canonical type 3 channels control the vascular contractility of mouse mesenteric arteries

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    Transient receptor potential canonical type 3 (TRPC3) channels are non-selective cation channels and regulate intracellular Ca2+ concentration. We examined the role of TRPC3 channels in agonist-, membrane depolarization (high K+)-, and mechanical (pressure)-induced vasoconstriction and vasorelaxation in mouse mesenteric arteries. Vasoconstriction and vasorelaxation of endothelial cells intact mesenteric arteries were measured in TRPC3 wild-type (WT) and knockout (KO) mice. Calcium concentration ([Ca2+]) was measured in isolated arteries from TRPC3 WT and KO mice as well as in the mouse endothelial cell line bEnd.3. Nitric oxide (NO) production and nitrate/nitrite concentrations were also measured in TRPC3 WT and KO mice. Phenylephrine-induced vasoconstriction was reduced in TRPC3 KO mice when compared to that of WT mice, but neither high K+- nor pressure-induced vasoconstriction was altered in TRPC3 KO mice. Acetylcholine-induced vasorelaxation was inhibited in TRPC3 KO mice and by the selective TRPC3 blocker pyrazole-3. Acetylcholine blocked the phenylephrine-induced increase in Ca2+ ratio and then relaxation in TRPC3 WT mice but had little effect on those outcomes in KO mice. Acetylcholine evoked a Ca2+ increase in endothelial cells, which was inhibited by pyrazole-3. Acetylcholine induced increased NO release in TRPC3 WT mice, but not in KO mice. Acetylcholine also increased the nitrate/nitrite concentration in TRPC3 WT mice, but not in KO mice. The present study directly demonstrated that the TRPC3 channel is involved in agonist-induced vasoconstriction and plays important role in NO-mediated vasorelaxation of intact mesenteric arteries.Fil: Yeon, Soo-In. Yonsei University College of Medicine; Corea del SurFil: Kim, Joo Young. Yonsei University College Of Medicine; . Yonsei University College of Medicine; Corea del SurFil: Yeon, Dong-Soo. Kwandong University College of Medicine; Corea del SurFil: Abramowitz, Joel. National Institute of Environmental Health Sciences; Estados UnidosFil: Birnbaumer, Lutz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. National Institute of Environmental Health Sciences; Estados UnidosFil: Muallem, Shmuel. National Institutes of Health; Estados UnidosFil: Lee, Young-Ho. Yonsei University College of Medicine; Corea del Su

    Japanese Population Politics as Viewed through Fertility Surveys in the 1940s and 1950s

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    This article traces the trajectory of discourses on population through fertility surveys administered in Japan in the 1940s and 1950s and unpacks their political significance. During this period, the frame through which Japan viewed population evolved rapidly from overpopulation theory to declining population society theory/ population resource theory to birth control theory. Until the 1930s, the problem of overpopulation in rural areas was severe, and the Japanese state attempted to resolve the issue through industrialization and overseas immigration. However, the Japanese government did not consider birth control as an alternative measure by which to address the problem. During this era, following the First World War, there was a notion of the period as the total-war era, in which populations were identified as a physical resource. Additionally, eyeing European states that had transitioned into societies with declining populations and deeming their powers weakened by this development, Japan endeavored to learn from their perceived mistakes. In 1940, Japans Ministry of Health and Welfare observed differences in fertility across the urban-rural divide, as well as differences between careers, via a fertility survey. The Population Policy Establishment Guidelines (Jinkō seisaku kakuritsu yōkō, 1941) were enacted on the basis of this survey. However, during the US occupation period, the population discourse in Japan quickly transitioned toward one of population control via birth control. With the return of populations from the Asian mainland and a baby boom following defeat in the Second World War, Japanese society faced the twin problems of unemployment and poverty. Birth control emerged as a direct means of resolving these problems. Furthermore, birth control was envisioned as a virtue of civil subjectivity that could guarantee the quality of the population while also determining a rational family size. By subsidizing the research costs incurred by conducting fertility surveys, as well as expanding scholarly exchanges for Japanese demographic researchers, private US foundations, headed by the Rockefeller Foundation, played a crucial role in the transition of population discourses in Japan. Meanwhile, an obsession with racial purity and the supposed superiority of the Japanese national population has always existed as a part of population discourses in Japan. Prior to 1945, the results of Japans fertility surveys were subject to comparisons with those in China, the USSR, and India, and utilized in a manner that prompted a security crisis. A sense of crisis concerning high fertility rates among colonized populations was also acute. This spurred attempts by the Japanese state to remove minority populations following 1945. It is necessary to re-examine the grand life-cycle of the Japanese populace from an overpopulated society to a low-birthrate, aging society within the historical context of population discourse/political constructions of representation

    Dominant Channel Estimation via MIPS for Large-Scale Antenna Systems with One-Bit ADCs

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    In large-scale antenna systems, using one-bit analog-to-digital converters (ADCs) has recently become important since they offer significant reductions in both power and cost. However, in contrast to high-resolution ADCs, the coarse quantization of one-bit ADCs results in an irreversible loss of information. In the context of channel estimation, studies have been developed extensively to combat the performance loss incurred by one-bit ADCs. Furthermore, in the field of array signal processing, direction-of-arrival (DOA) estimation combined with one-bit ADCs has gained growing interests recently to minimize the estimation error. In this paper, a channel estimator is proposed for one-bit ADCs where the channels are characterized by their angular geometries, e.g., uniform linear arrays (ULAs). The goal is to estimate the dominant channel among multiple paths. The proposed channel estimator first finds the DOA estimate using the maximum inner product search (MIPS). Then, the channel fading coefficient is estimated using the concavity of the log-likelihood function. The limit inherent in one-bit ADCs is also investigated, which results from the loss of magnitude information.Comment: to appear in GLOBECOM 2018, Abu Dhabi, UA

    Geomagnetic field influences probabilistic abstract decision-making in humans

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    To resolve disputes or determine the order of things, people commonly use binary choices such as tossing a coin, even though it is obscure whether the empirical probability equals to the theoretical probability. The geomagnetic field (GMF) is broadly applied as a sensory cue for various movements in many organisms including humans, although our understanding is limited. Here we reveal a GMF-modulated probabilistic abstract decision-making in humans and the underlying mechanism, exploiting the zero-sum binary stone choice of Go game as a proof-of-principle. The large-scale data analyses of professional Go matches and in situ stone choice games showed that the empirical probabilities of the stone selections were remarkably different from the theoretical probability. In laboratory experiments, experimental probability in the decision-making was significantly influenced by GMF conditions and specific magnetic resonance frequency. Time series and stepwise systematic analyses pinpointed the intentionally uncontrollable decision-making as a primary modulating target. Notably, the continuum of GMF lines and anisotropic magnetic interplay between players were crucial to influence the magnetic field resonance-mediated abstract decision-making. Our findings provide unique insights into the impact of sensing GMF in decision-makings at tipping points and the quantum mechanical mechanism for manifesting the gap between theoretical and empirical probability in 3-dimensional living space.Comment: 32 pages, 5 figures, 4 supplementary figures, 2 supplementary tables, and separate 15 ancillary file

    Development of Ocean Economy Satellite Account in Korea

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    The ocean has emerged as a new solution to new growth engines. However, some issues remain to be resolved, such as unified concepts and evaluation methods for the ocean economy, comparability between the national economy and the ocean economy, and the connection between global and national assessments. Since the ocean economy comprises various complex industries, it is necessary to establish policies based on an objective analysis of economic indicators. However, there have been difficulties in analyzing industrial activities related to the ocean economy within the national account system. To more accurately calculate the share of the ocean economy sector in the national economy, it is necessary to create a satellite account that reflects the characteristics of the ocean economic activities while maintaining consistency with the national account. This study aims to develop a satellite account for the ocean economy, a measurement of GDP in the ocean sector, which can correspond with the national accounts system and intends to propose Korean practices as a framework in the process of discussing international guidelines. This study introduces a potential structure for Korea\u27s ocean economy satellite account, the principles, methods, and data used for value coefficient estimation, and finally presents pilot results for several components of the ocean economy. This account can be utilized to diagnose the economic position as well as the policy effects of Korea’s ocean economy sector while contributing to the establishment of mid-to-long term industrial policies. This case study of Korean practices can be an important example that offers a framework and principles for international discussions

    Two novel mutations of Wiskott–Aldrich syndrome: the molecular prediction of interaction between the mutated WASP L101P with WASP-interacting protein by molecular modeling

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    AbstractWiskott–Aldrich syndrome (WAS) is an X-linked disorder characterized by eczema, thrombocytopenia and increased susceptibility of infections, with mutations of the WAS gene being responsible for WAS and X-linked thrombocytopenia. Herein, two novel mutations of WAS at T336C on exon 3, and at 1326–1329, a G deletion on exon 10, resulting in L101P missense mutation and frameshift mutation 444 stop, respectively, are reported. The affected patients with either mutation showed severe suppression of WAS protein (WASP) levels, T cell proliferation, and CFSE-labeled T cells division. Because WASP L101 have not shown direct nuclear Overhauser effect (NOE) contact with the WASP-interacting protein (WIP) in NMR spectroscopy, molecular modeling was performed to evaluate the molecular effect of WASP P101 to WIP peptide. It is presumed that P101 induced a conformational change in the Q99 residue of WASP and made the side chain of Q99 move away from the WIP peptide, resulting in disruption of the hydrogen bond between Q99 WASP and Y475 WIP. A possible model for the molecular pathogenesis of WAS has been proposed by analyzing the interactions of WASP and WIP using a molecular modeling study
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