Heuristic Algorithm for Virtual Link Configuration in AFDX Networks

REACTION 2014. 3rd International Workshop on Real-time and Distributed Computing in Emerging Applications. Rome, Italy. December 2nd, 2014.As the AFDX networks have been increasingly employed for airborne networks, much research works have been conducted to support real-time service in a deterministic way. However, since they assumed the preconfigured networks where all involved parameters were already determined, the impact of configuration algorithm is not well explored. To solve this problem, in this paper, we focus on how to reduce the required bandwidth by configuring virtual link which logically consists of at least one or more application flows. To achieve this, new heuristic algorithms have been proposed by applying well-known greedy approach while taking essential constraints of AFDX networks into account. To evaulate the performance of proposed scheme, diverse case studies for airborne application flows are concerned and their number of virtual links as well as required bandwidth are compared.This work was supported by Basic Science Research Program (NRF-2013R1A1A2A10004587) through the National Research Foundation of Korea (NRF) funded by the Ministry of Education and the MSIP(Ministry of Science, ICT & Future Planning), Korea, under the ”SW master’s course of a hiring contract” support program (NIPA-2014-HB301-14- 1014) supervised by the NIPA(National IT Industry Promotion Agency).Publicad

Relationship Between Audit Opinion And Credit Rating: Evidence From Korea

In this study, we investigate the relationship between credit ratings and audit opinions of financially distressed companies impending bankruptcy. Using Korean publicly-held firms for the years 2007 through 2014, we analyze 97 bankrupt companies with credit rating available before they file bankruptcy. Following prior research (Geiger et al., 2005), we find that the propensity to issue a going concern audit opinion is associated with the credit score issued by NICE immediately prior to the audit opinion date. We also compare credit ratings to audit opinions to investigate which of the two is more conservative and provides the earlier signal of bankruptcy. Through empirical test, we can conclude that audit system has more successfully predictive function in signaling preceding bankruptcy than CRAs' system with overly optimism. We argue that after a string of high-profile corporate failures such as Enron and Arthur Anderson’s bankruptcies, legislators portrayed auditors negatively and ultimately led to the enactment and more forced liabilities and thus auditors become more conservative. To remedy CRAs' failure by providing overly optimism, we suggest that like as auditors, CRAs' regulations should be more strengthened on their liability about issuing credit ratings

Stability conditions and guest distribution of the methane plus ethane plus propane hydrates or semiclathrates in the presence of tetrahydrofuran or quaternary ammonium salts

In this study, the stability conditions and guest distributions of methane (CH4) + ethane (C2H6) + propane (C 3H8) hydrates or semiclathrates are examined in the presence of tetrahydrofuran (THF) and quaternary ammonium salts such as tetra-n-butylammonium bromide (TBAB) and tetra-n-butylammonium fluoride (TBAF) through thermodynamic and spectroscopic analyses. The three-phase equilibria of hydrate or semiclathrate (H), liquid water (LW), and vapor (V) for the quinary CH4 + C2H6 + C3H 8 + THF + water, CH4 + C2H6 + C 3H8 + TBAB + water, and CH4 + C 2H6 + C3H8 + TBAF + water mixtures with various concentrations were experimentally measured in order to determine the hydrate or semiclathrate stability conditions. The experimental results demonstrated that all thermodynamic promoters such as THF, TBAB, and TBAF used in this study could remarkably stabilize the hydrate dissociation conditions even though the degree of stabilization was dependent on the type of promoters and on the concentrations of each promoter used. From the 13C NMR analysis, preferential occupation of CH4 molecules in the hydrate or semiclathrate lattices was observed at the stoichiometric concentrations of each hydrate or semiclathrate structure. However, at the THF mole fraction lower than 0.056, the large cages of structure II were shared by CH4, C2H6, C3H8, and THF molecules, whereas the small cages were occupied by only CH4 molecules. The results given in this study are very useful in understanding the thermodynamic stability, structural characteristics, and guest distribution of the hydrates or semiclathrates with multi-components in the presence of thermodynamic promoters for further applications in gas storage and separation processes.close1