4,245 research outputs found
Review of Literature and Curricula in Smart Supply Chain & Transportation
This study provides a review of existing smart supply chain management (SCM) literature and current course offerings in order to identify unexplored implications of smart SCM. Specifically, the study focuses on curricula within the state of California to derive potential opportunities for the relevant practitioners in the Bay Area. In addition, the study further extends curriculum review to other well-recognized SCM programs around the U.S. By exploring current relevant course offerings from different academic institutions for higher education (i.e., universities), this research aims to deliver general ideas useful to knowledge practitioners in fields concerning SCM. Finally, the research illustrates a conceptual framework aimed at fostering familiarity with the necessary research topics for the evolving smart SCM
Consistency Index-Based Sensor Fault Detection System for Nuclear Power Plant Emergency Situations Using an LSTM Network
A nuclear power plant (NPP) consists of an enormous number of components with complex interconnections. Various techniques to detect sensor errors have been developed to monitor the state of the sensors during normal NPP operation, but not for emergency situations. In an emergency situation with a reactor trip, all the plant parameters undergo drastic changes following the sudden decrease in core reactivity. In this paper, a machine learning model adopting a consistency index is suggested for sensor error detection during NPP emergency situations. The proposed consistency index refers to the soundness of the sensors based on their measurement accuracy. The application of consistency index labeling makes it possible to detect sensor error immediately and specify the particular sensor where the error occurred. From a compact nuclear simulator, selected plant parameters were extracted during typical emergency situations, and artificial sensor errors were injected into the raw data. The trained system successfully generated output that gave both sensor error states and error-free states
Identification of SNPs in TG and EDG1 genes and their relationships with carcass traits in Korean cattle (Hanwoo)
Thyroglobulin (TG) gene was known to be regulated fat cell growth and differentiation and the endothelial
differentiation sphingolipid G-protein-coupled receptor 1 (EDG1) gene involves blood vessel formation and known to
be affecting carcass traits in beef cattle. The aim of this study was to identify the single nucleotide polymorphisms (SNPs)
in both TG and EDG1 genes and to analyze the association with carcass traits in Korean cattle (Hanwoo). The T354C
SNP in TG gene located at the 3’ flanking region and c.-312A>G SNP located at 3’-UTR of EDG1 gene were used
for genotyping the animals using PCR-RFLP method. Three genotypes were identified in T354C SNP in TG gene and
only two AA and AG genotypes were observed for the c.-312A>G SNP in EDG1 gene. The results indicated that T354C
SNP in TG gene was not significantly associated with carcass traits. However, the c.-312A>G SNP in EDG1 gene had
significant effects on backfat thickness (BF) and yield index (YI). These results may provide valuable information for
further candidate gene studies affecting carcass traits in Korean cattle and may use as marker assisted selection for
improving the quality of meat in Hanwoo.
Key words : TG, EDG1, Carcass traits, Hanwo
Business Groups and Tunneling: Evidence from Private Securities Offerings by Korean Chaebols
Using a comprehensive sample of equity-linked private securities offerings by Korean firms from 1989 to 2000, we examine whether such offerings can be used as a mechanism for wealth transfer between issuers and acquirers. For deals involving issuers and acquirers in the same business group (chaebol), the announcement returns for chaebol-affiliated issuers with good past performance are lower than those for other types of issuers if the price discount is larger. In contrast, this deal leads to more value creation for chaebol-affiliated acquirers than other types of acquirers. Furthermore, well-performing chaebol-affiliated acquirers experience a larger wealth loss than other types of acquirers if they buy securities from poorly performing issuers in the same chaebol. We also find that chaebol firms with good past performance tend to sell private securities at a low price to their member firms. This evidence is consistent with tunneling within business groups.
Probabilistic safety assessment-based importance analysis of cyber-attacks on nuclear power plants
With the application of digital technology to safety-critical infrastructures, cyber-attacks have emerged as one of the new dangerous threats. In safety-critical infrastructures such as a nuclear power plant (NPP), a cyber-attack could have serious consequences by initiating dangerous events or rendering important safety systems unavailable. Since a cyber-attack is conducted intentionally, numerous possible cases should be considered for developing a cyber security system, such as the attack paths, methods, and potential target systems. Therefore, prior to developing a risk-informed cyber security strategy, the importance of cyber-attacks and significant critical digital assets (CDAs) should be analyzed. In this work, an importance analysis method for cyber-attacks on an NPP was proposed using the probabilistic safety assessment (PSA) method. To develop an importance analysis framework for cyber-attacks, possible cyber-attacks were identified with failure modes, and a PSA model for cyber-attacks was developed. For case studies, the quantitative evaluations of cyber-attack scenarios were performed using the proposed method. By using quantitative importance of cyber-attacks and identifying significant CDAs that must be defended against cyber-attacks, it is possible to develop an efficient and reliable defense strategy against cyber-attacks on NPPs
Estimates of Discharge Coefficient in Levee Breach Under Two Different Approach Flow Types
The amount of released water (discharge) in a levee breach is a primary input variable to establish an emergency action plan for the area next to the levee. However, although several studies have been conducted, there is still no widely applicable discharge coefficient formula; this needs to be known to estimate discharge amount through an opening caused by a levee breach. Sometimes, the discharge coefficient developed for a sharp crested side weir is used to rate the discharge, but, in case of a levee breach, the resulting geometry and flow types are similar to that over a broad crested weir. Thus, in this study, two different openings—rectangular and trapezoidal shape—are constructed in the center of a levee at a height of 0.6m to replicate levee breach scenarios, and the effect of two different approach flow types—the river type approach and reservoir type approach—are explored to suggest a discharge coefficient formula applicable for discharge rating for a levee breach. The results show that the ratio of head above the bottom of an opening and the opening width is a key variable for calculating the discharge coefficient of a reservoir type, but the approach Froude number should also be considered for a river type approach. The measured data are used to improve rating equations and will be useful in the future to validate computational fluid dynamics simulations of wave propagation during levee failure into the inundation area
Corrosion Inhibitors for Reinforced Concrete: A Review
The objective of the topic is to review the recent trends in corrosion inhibitors for reinforced concrete and their application in the laboratory and field conditions. Inhibitors are chemical substances which when added to the concrete in small concentrations will inhibit or prolong the time to initiation of corrosion in concrete structures. This chapter focuses on the type of inhibitors used in concrete based upon their mode of action and the way of application. The section deals with anodic, cathodic, mixed inhibitors; performance of admixed inhibitor vs. migrating/surface applied inhibitor and their evaluation studies; and electrochemical injection of corrosion inhibitor (EICI) in concrete and electrochemical chloride extraction techniques has been reviewed
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