An evaluation of quality of service characteristics of PACS packet channel

A novel application on the recently emerging wireless Personal Communications Systems (PCS) is the multimedia communication. In this paper, we evaluate multimedia communications capability and quality of service characteristics of one of the PCS standards, Personal Access Communications System's (PACS) packet channel (PPC) using simulation modeling. The performance of PPC's slot aggregation and data-sense multiple access techniques are studied by considering the downlink and uplink in a single cell and combined uplink/downlink in two cells and changing various parameters such as the number of users and certain protocol parameters. Interconnection of PPC with the Internet is discussed next. Frame rates of MPEG-1 coded images transmitted in a PACS cell as IP datagrams are determined. Handover characteristics of PPC downlink are studied by changing different parameters such as the cell size, the speed of the mobile host and time between handovers. The results clearly establish that multimedia communication on PPC is only feasible at lower bandwidths and frame rates and only a few users per cell can be supported. Careful tuning of PPC protocol parameters is required. There is one parameter whose variation gives opposite results on the downlink and uplink.     

Home agent placement and IP address management for integrating WLANs with cellular networks

Seamless roaming between cellular networks (3G or upcoming 4G) and wireless local area networks can be provided using Mobile IP. However, GPRS/UMTS and 802.11-based WLAN networks have no native support for mobile IP. Mobile IP requires the deployment of home agents and a protocol between the mobile nodes, home agent, and corresponding nodes. We address the home agent placement and home address assignment issues for supporting mobile IP for heterogeneous roaming. Placement techniques for mobile IP home agents are presented including dynamic HA assignment in either WLAN or cellular network domains using the diameter mobile IP application. Next, we present several IPv4 home address assignment schemes for mobile nodes visiting in the WLAN domain such as NAT/NAPT traversal, reverse tunneling, and mobile VPNs. It is shown that HA placement and address management are orthogonal, and any combination is possible. Various architectures for both issues are evaluated against the optimal solutions     

Assessing colour values of polyester fabrics produced from fibres having different cross-sectional shapes after abrasion

This study assesses the colour, colour difference and colour strength values obtained for eight disperse-dyed polyester fabric samples produced from full and hollow round and trilobal fibres after four sets of abrasion cycle. Each fabric was produced from the same yarns in warp and weft directions. The L *, C *ΔE^*_ab and K/S values of the undyed fabrics and dyed fabrics before and after increasing cycles of abrasion are presented and discussed. Fabrics produced from full and hollow fibres showed great differences regarding colour values in abrasion behaviour. Fabrics produced from hollow fibres were found to be very sensitive to increasing abrasion cycles.     

Mobile sensor network programming system

Sensors carried by moving objects in the cities can be used in various applications such as environmental monitoring, traffic control and recreational purposes. A mobile sensor network can be formed by sensors carried by people or buses. In this paper, we will present a mobile sensor network programming system (MSNPS) that can program or reprogram such mobile sensor networks. The programming process is usually initiated by a user from the Internet. MSNPS uses a gateway protocol to bridge the Internet and sensor network, so that control and data messages can be exchanged between these two networks. MSNPS sends the program data to the targeted sensor platforms using a tree structure formed by control messages. We developed a prototype implementation, and analyzed MSNPS system performance. We also simulated the system in a mobile sensor network.     

A hybrid DNN–LSTM model for detecting phishing URLs

Neural Computing and Applications - Phishing is an attack targeting to imitate the official websites of corporations such as banks, e-commerce, financial institutions, and governmental...     

Corrosion and mechanical-microstructural aspects of dissimilar joints of Ti–6Al–4V and Al plates

In this study, Ti–6Al–4V and Al plates were joined by explosive welding at various explosive loads. Tensile-shear, bending, hardness, microstructure and corrosion behaviours of the explosively joined samples were investigated. At the end of the tensile-shear tests carried out according to ASTM D 3165-95 standard, no seperation was observed in the interfaces of the joined samples. The results of the bending tests also showed no sign of any distinctive seperation, crack and tear in the interfaces. The highest hardness values were measured in regions next to interfaces. The optical microscope and SEM examinations revealed that an increment in wavelength and amplitude was observed with increasing explosive load. It is seen from the corrosion test results that materials loss was high at the beginning of the corossion tests but the rate of material loss decreased later on. Furthermore, increasing deformation with increasing explosive load increased the materials loss in corrosion tests.