Difficulty of internal bond prediction of particleboard using the density profile

The relationship between density profile and internal bond (IB) of commercial particleboards was investigated. Minimum density was theoretically related to the IB, but the correlation coefficient between them was low at 0.435. The correlation coefficients between core layer densities and IB were also low. These correlation coefficients were approximately 0.460. The IB is influenced not only by density, but also by other factors such as the manufacturing conditions. In addition, commercial particleboards have a narrow density range. This narrow density range results in overfitting, showing a low correlation coefficient. Thus, predicting the IB using density profile was difficult.

Research on Financial Systemic Risk in ASEAN Region

The research of financial systemic risk is an important issue, however the research on the financial systemic risk in ASEAN region lacks. This paper uses the minimum density method to calculate the interbank network of ASEAN countries and uses the node centrality to judge the systemically important banks of various countries. Then the DebtRank algorithm is constructed to calculate the systemic risk value based on the interbank network. By comparing the systemic risk values obtained through the initial impact on the system important banks and non-important banks, we find that the systemic risk tends to reach the peak in the case of the initial impact on the system important banks. Furthermore, it is found that countries with high intermediary centrality and closeness centrality have higher systemic risk. It suggests that the regulatory authorities should implement legal supervision, strict supervision, and comprehensive supervision for key risk areas and weak links.

Breaking the rmax Barrier: Enhanced Approximation Algorithms for Partial Set Multicover Problem

Given an element set E of order n, a collection of subsets [Formula: see text], a cost cS on each set [Formula: see text], a covering requirement re for each element [Formula: see text], and an integer k, the goal of a minimum partial set multicover problem (MinPSMC) is to find a subcollection [Formula: see text] to fully cover at least k elements such that the cost of [Formula: see text] is as small as possible and element e is fully covered by [Formula: see text] if it belongs to at least re sets of [Formula: see text]. This problem generalizes the minimum k-union problem (MinkU) and is believed not to admit a subpolynomial approximation ratio. In this paper, we present a [Formula: see text]-approximation algorithm for MinPSMC, in which [Formula: see text] is the maximum size of a set in S. And when [Formula: see text], we present a bicriteria algorithm fully covering at least [Formula: see text] elements with approximation ratio [Formula: see text], where [Formula: see text] is a fixed number. These results are obtained by studying the minimum density subcollection problem with (or without) cardinality constraint, which might be of interest by itself.