2,670 research outputs found

    Effective Route Maintenance and Restoration Schemes in Mobile Ad Hoc Networks

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    This study proposes a location-based hybrid routing protocol to improve data packet delivery and to reduce control message overhead in mobile ad hoc networks. In mobile environments, where nodes move continuously at a high speed, it is generally difficult to maintain and restore route paths. Therefore, this study suggests a new flooding mechanism to control route paths. The essence of the proposed scheme is its effective tracking of the destination’s location based on the beacon messages of the main route nodes. Through experiments based on an NS-2 simulator, the proposed scheme shows improvements in the data packet delivery ratio and reduces the amount of routing control message overhead compared with existing routing protocols such as AODV, LAR, ZRP and AODV-DFR

    Impact of human factors for student pilots in approved flight training organizations in Korea

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    Statistics for aviation accidents in Korea show that the safety level of training flights is high. However, of the accidents that do occur, more than 80% occur due to human factors. Furthermore, because most causes of human factors-related accidents are “pilot error,” it is important for student pilots who will transport passengers to develop knowledge of safety and skills associated with human factors risk management to mitigate the risk of such accidents. To investigate the human factors that affect safety in training student pilots for flight, this study examined the correlation between events that are associated with accidents, differences according to the pilot’s experience level of flight training, and differences between student pilots who received flight training at approved collegiate flight education centers and those who did not. The study was conducted on human factors, focusing on the SHELL model. Using the SPSS software (ver. 17.0), correlation analyses, analyses of variance (ANOVA), and t-tests were conducted to generate statistical results. Briefly, the results of this study found that a student pilot’s natural ability and equipment in the cockpit are the important factors for safety for pilot on training flights. Additionally, the analysis of the differences between human factors according to the characteristics of student pilots’ groups shows that college student pilots are effected by immanent factors and organizational cultures. To date, there have been no accidents with related human casualties when training at collegiate “Approved Training Organizations” (ATOs) in Korea. However, accidents can occur at anytime and anywhere. Especially human factors, which cause most aviation accidents, have a wide reach and are impossible to eliminate. Because ATO is the starting point to lead the aviation industry of Korea, awareness of risks and initiatives to improve education/training of human factors is essential

    Linear operators that strongly preserve regularity of fuzzy matrices

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    An ntimesnntimes n fuzzy matrix AA is called {regular} if there is an ntimesnntimes n fuzzy matrix GG such that AGA=AAGA=A. We study the problem of characterizing those linear operators TT on the fuzzy matrices such that T(X)T(X) is regular if and only if XX is. Consequently, we obtain that TT strongly preserves regularity of fuzzy matrices if and only if there are permutation matrices PP and QQ such that it has the form T(X)=PXQT(X)=PXQ or T(X)=PXtQT(X)=PX^tQ for all fuzzy matrices XX

    Antioxidative and Antimutagenic Activities of 70% Ethanolic Extracts from Four Fungal Mycelia-Fermented Specialty Rices

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    The health-promoting potential of 70% ethanolic extracts of 4 rice varieties fermented with Monascus ruber, Phellinus linteus, Cordyceps sinensis and Agaricus blazei was evaluated mainly focusing on their antioxidative and antimutagenic capacities based on the following parameters: phenolic compound and phytic acid content; inhibitory activity on lipid peroxidation; scavenging activity on DPPH radical; suppressing ability on mitomycin C-induced mutagenesis in E. coli cells; and protective effect on 4-nitroquinoline oxide-triggered DNA lesion in V79 hamster cells. The fermented rice extracts were superior in overall health-promoting parameters compared to the source material. The higher antimutagenic activity of the fermented rice extracts might be in part caused by a larger amount of antioxidant constituents such as phenolic compounds or phytic acid. Of the fungal species, Monascus ruber was found to impart a marked increase in both the antioxidative and antimutagenic abilities to the source material. The current study suggests a possibility that such fermented rice may contribute to the prevention of lifestyle-related diseases such as cancer through a daily intake of rice-based diets

    Digital production of traditional costumes

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    The purpose of this study is to find out the possibility of reproducing traditional costumes using the digital technology. For this, we selected a women’s robe and a men’s suit in the rococo era of the 18th century. For the reconstruction, we analyzed the costume focusing on the figurative features of the silhouette, and then applied the 3D technology to reconstruct them
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