Search

Conducting polymers offer the ability to create electronic devices that are lightweight with relatively simple processing compared to their inorganic counterparts. They have recently gained attention in the wearable electronics field due their ability to exhibit flexibility and low stiffness while conducting electricity. However, conducting polymers are not intrinsically flexible and must be modified, usually at the expense of electrical performance, or through the use of expensive and toxic additives. Here, we explore the use of architected materials to tune a conductive polymer's mechanical properties without chemical modification. To do so, a reliable and high-throughput 3D printing system for a conducting polymer-based hydrogel was established. The system utilizes a stereolithography apparatus (SLA) to 3D print a hydrogel of almost any 3D shape. The hydrogel acts as a dopant and structural component for a subsequently grown conducting polymer. This means a conducting polymer, which is usually limited to being a thin film or a stochastic foam, can be made into specific and complex geometries, enabling the tailoring of its mechanical properties through architecture, without compositing or chemical modification. When architected into a lattice, the conducting polymers can withstand compressive strain up to 80% without failure, whereas their bulk counterpart reaches just 25% strain before undergoing brittle fracture. The architected conducting polymers also exhibit a strain rate invariant stress-strain curve, suggesting that a potential strain rate invariant electrical resistance behavior may exist, but further investigation is required.

Conducting polymers offer the ability to create electronic devices that are lightweight with relatively simple processing compared to their inorganic counterparts. They have recently gained attention in the wearable electronics field due their ability to exhibit flexibility and low stiffness while conducting electricity. However, conducting polymers are not intrinsically flexible and must be modified, usually at the expense of electrical performance, or through the use of expensive and toxic additives. Here, we explore the use of architected materials to tune a conductive polymer's mechanical properties without chemical modification. To do so, a reliable and high-throughput 3D printing system for a conducting polymer-based hydrogel was established. The system utilizes a stereolithography apparatus (SLA) to 3D print a hydrogel of almost any 3D shape. The hydrogel acts as a dopant and structural component for a subsequently grown conducting polymer. This means a conducting polymer, which is usually limited to being a thin film or a stochastic foam, can be made into specific and complex geometries, enabling the tailoring of its mechanical properties through architecture, without compositing or chemical modification. When architected into a lattice, the conducting polymers can withstand compressive strain up to 80% without failure, whereas their bulk counterpart reaches just 25% strain before undergoing brittle fracture. The architected conducting polymers also exhibit a strain rate invariant stress-strain curve, suggesting that a potential strain rate invariant electrical resistance behavior may exist, but further investigation is required.

Network management and anomaly detection are challenges in high-speed networks due to the high volume of packets that has to be analysed. Flow-based analysis is a scalable method which reduces the high volume of network traffic by dividing it into flows. As sampling methods are extensively used in flow generators such as NetFlow, the impact of sampling on the performance of flow-based analysis needs to be investigated. Monitoring using sampled traffic is a well-studied research area, however, the impact of sampling on flow-based anomaly detection is a poorly researched area. This paper investigates flow sampling methods and shows that these methods have negative impact on flow-based anomaly detection. Therefore, we propose an efficient probabilistic flow sampling method that can preserve flow traffic distribution. The proposed sampling method takes into account two flow features: Destination IP address and octet. The destination IP addresses are sampled based on the number of received bytes. Our method provides efficient sampled traffic which has the required traffic features for both flow-based anomaly detection and monitoring. The proposed sampling method is evaluated using a number of generated flow-based datasets. The results show improvement in preserved malicious flows.

SMS je služba zasílání krátkých textových zpráv mezi terminály různých typů sítí. Služba zasílání SMS zpráv, po úspěšném využití v mobilních sítích, byla zprovozněna i v sítích pevných. Zde jsou možné dva typy doručení SMS, jak v datové podobě na display terminálu, tak v hlasové podobě. Práce se v teoretické části zabývá rozborem FSK modulace a popsáním složení dat SMS zpráv podle doporučení ETSI. Objasnění kódování SMS zpráv bylo cílem analytické části práce. Většina zpráv různých vstev protokolu je vyjádřena v hexadecimálním tvaru, některé zprávy jsou vyjádřeny binárně. Podrobné vysvětlení významu jednotlivých parametrů zpráv ze získaných dat je důležité k pochopení datové výměny mezi SMS centrem a terminálem při přenosu krátkých textových zpráv na pevných linkách., SMS is a communication service that allow the exchange of short text messages between terminals belongs to different types of networks. Service of sending SMS, after successful using in mobile networks, was get in to service in fixed networks as well. In this network the two possibilities of delivery exist, first one is data form of delivery and the second one is speech delivery. The work is in their theoretical part focused on analysis of FSK modulation and on description of SMS dates structure according to ETSI recommendations. Analytical part of work was focused on clearing of SMS coding. Almost all messages from different layers of protocols are expressed by hexadecimal numbers, but some of them are expressed by binary numbers. Detailed explanation of meaning of particular messages parameters in obtained data is important for understanding to data exchange between SMS centre and terminal during the SMS messages transfer on fixed line., Import 29/09/2010