When Delta joined the code share between Continental and Northwest in 2003, these three legacy carriers formed the only three-way U.S. domestic code sharing partnership. In 2008, Delta and Northwest announced their in...When Delta joined the code share between Continental and Northwest in 2003, these three legacy carriers formed the only three-way U.S. domestic code sharing partnership. In 2008, Delta and Northwest announced their intention to merge. The merger was granted by the Department of Justice six months later. This paper analyzes the effects of the three-way code share and the effects of the merger between these two previous code sharing partners. I find both competitive effects and anti-competitive effects of code sharing, i.e., mean market price decrease in non-hub markets and price increase in hub-to-hub markets. Meanwhile, passenger volume increases significantly. Moreover, rivals＇ responses are to move price in the same direction as code sharing partners. I find an increase in Herfindahl-Hirschman Index （HHI） and a reduction in traffic after the merger. Specifically, HHI increases for over 1,000 points in markets where merging airlines were either duopolistic or with a third carrier. Pre-merger code sharing markets experience an increase in HHI due to the disappearance of the code sharing contract. Low cost carrier entry mitigates merger effects.展开更多
In this paper, we analyze the video steganography technique, which is used to ensure national security and the confidentiality of the information of governmental agencies and enterprises. Videos may be used to transmi...In this paper, we analyze the video steganography technique, which is used to ensure national security and the confidentiality of the information of governmental agencies and enterprises. Videos may be used to transmit secrets and conduct covert communication. As such, we present an algorithm based on a secret sharing scheme and an Error-Correcting Code（ECC）, which combines Grey Relational Analysis（GRA） with a partition mode in video compression standard H.264/AVC. First, we process secret information by secret sharing, and then use an ECC to process the obtained information. Moreover, we choose the Discrete Cosine Transform（DCT） blocks using GRA, and then use rules to hide the pretreated information in DCT coefficients of the video frames. Experimental results indicate that our algorithm has good invisibility, better robustness, good anti-steganalysis ability, and little influence on the bit rate of the video carrier. In addition, the bit error rate is low after attacks such as noise, filtering,or frame loss in the simulation environment.展开更多
文摘When Delta joined the code share between Continental and Northwest in 2003, these three legacy carriers formed the only three-way U.S. domestic code sharing partnership. In 2008, Delta and Northwest announced their intention to merge. The merger was granted by the Department of Justice six months later. This paper analyzes the effects of the three-way code share and the effects of the merger between these two previous code sharing partners. I find both competitive effects and anti-competitive effects of code sharing, i.e., mean market price decrease in non-hub markets and price increase in hub-to-hub markets. Meanwhile, passenger volume increases significantly. Moreover, rivals＇ responses are to move price in the same direction as code sharing partners. I find an increase in Herfindahl-Hirschman Index （HHI） and a reduction in traffic after the merger. Specifically, HHI increases for over 1,000 points in markets where merging airlines were either duopolistic or with a third carrier. Pre-merger code sharing markets experience an increase in HHI due to the disappearance of the code sharing contract. Low cost carrier entry mitigates merger effects.
基金supported by the National Natural Science Foundation of China(Nos.61379152 and 61403417)
文摘In this paper, we analyze the video steganography technique, which is used to ensure national security and the confidentiality of the information of governmental agencies and enterprises. Videos may be used to transmit secrets and conduct covert communication. As such, we present an algorithm based on a secret sharing scheme and an Error-Correcting Code（ECC）, which combines Grey Relational Analysis（GRA） with a partition mode in video compression standard H.264/AVC. First, we process secret information by secret sharing, and then use an ECC to process the obtained information. Moreover, we choose the Discrete Cosine Transform（DCT） blocks using GRA, and then use rules to hide the pretreated information in DCT coefficients of the video frames. Experimental results indicate that our algorithm has good invisibility, better robustness, good anti-steganalysis ability, and little influence on the bit rate of the video carrier. In addition, the bit error rate is low after attacks such as noise, filtering,or frame loss in the simulation environment.
