ABSTRACT:Interpenetrating polymer network (IPN) hydrogels composed of chitosan and poly(acrylic acid) (PAAc) were synthesized by UV irradiation method, and their structure, crystallinity, swelling behavior, thermal property, and mechanical property were investigated. Chitosan/PAAc IPNs exhibited relatively high equilibrium water content and also showed reasonable sensitivity to pH. From the swelling behaviors at various pH's, Fourier transform infrared spectra at high temperature and thermal analysis confirmed the formation of polyelectrolyte complex due to the reaction between amino groups in chitosan and carboxyl groups in PAAc. For this reason, even at a swollen state, the present chitosan/PAAc IPNs possess good mechanical properties. Particularly, the CA-2 sample (with a weight ratio of chitosan/PAAc ϭ 50/50, molar ratio [NH 2 ]/[COOH] ϭ 25/75) showed the lowest equilibrium water content and free water content, attributed to the more compact structure of the polyelectrolyte than CA-1 or CA-3 due to the high amount of interchain bond within the IPN.

Interpenetrating polymer network (IPN) hydrogels composed of chitosan and poly(acrylic acid) (PAAc) were synthesized by UV irradiation method, and their structure, crystallinity, swelling behavior, thermal property, and mechanical property were investigated. Chitosan/PAAc IPNs exhibited relatively high equilibrium water content and also showed reasonable sensitivity to pH. From the swelling behaviors at various pH's, Fourier transform infrared spectra at high temperature and thermal analysis confirmed the formation of polyelectrolyte complex due to the reaction between amino groups in chitosan and carboxyl groups in PAAc. For this reason, even at a swollen state, the present chitosan/PAAc IPNs possess good mechanical properties. Particularly, the CA-2 sample (with a weight ratio of chitosan/PAAc ϭ 50/50, molar ratio [NH 2 ]/[COOH] ϭ 25/75) showed the lowest equilibrium water content and free water content, attributed to the more compact structure of the polyelectrolyte than CA-1 or CA-3 due to the high amount of interchain bond within the IPN.

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Abstract.If efficient network analysis tools were available, it could become possible to detect the attacks, anomalies and to appropriately take action to contain the attacks. In this paper, we suggest a technique for traftic anomaly detection based on analyzing correlation of destination IP addresses in outgoing traffic at an egress router. This address correlation data are transformed through discrete wavelet transform for effective detection of anomalies through statistical analysis. Our techniques can be employed for postmartern and real-time analysis of outgoing network traffic at a campus edge. Results from tracedriven evaluation suggest that proposed approach could provide an effective means of detecting anomalies close to the network. We also present data analyzing the correlation of port numbers as a means of detecting anomalies.