1,734 research outputs found
Universalism Denied: C. S. Lewis’ Unpublished Letters to Alan Fairhurst
No full text In a 6 September, 1959 unpublished letter to Reverend Alan Fairhurst, C.S. Lewis clearly denies Universalism. In a second unpublished letter to Fairhurst dated 9 September, 1959, Lewis offered evidence that he was not an Annihilationist. Both letters are unusual because Lewis was normally hesitant to discuss eschatology, particularly the nature of hell. This essay presents both previously unpublished letters in their entirety, discusses the reasons for their importance, sets them in the context of Lewis' other writings on hell and renders a conclusion, based on Lewis' own words, about his positions on Universalism and Annihilationism. </jats:p
Swelling and shrinking kinetics of a lamellar gel phase
No full textWe investigate the swelling and shrinking of L lamellar gel phases composed of surfactant and fatty alcohol after contact with aqueous poly(ethyleneglycol) solutions. The height change Δh(t) is diffusionlike with a swelling coefficient S: Δh=S√t. On increasing polymer concentration, we observe sequentially slower swelling, absence of swelling, and finally shrinking of the lamellar phase. This behavior is summarized in a nonequilibrium diagram and the composition dependence of S quantitatively described by a generic model. We find a diffusion coefficient, the only free parameter, consistent with previous measurements
A cross-layer architecture for satellite network security: CL-IPsec
No full textCross-layer architectures (CLAs) are proposed to improve performance in networks where physical layer impairments are unpredictable and provision of security services may be challenging, as in satellite networks. This paper proposes an extension to the IPsec protocol, named Cross-Layer IPsec (CL-IPsec), able to provide authentication and integrity services through a cross-layer architecture when the adopted protocol is UDP-Lite. This is suitable for multicast applications that are cost-effectively provided by satellite systems. A satellite emulation platform has been used to validate the CL-IPsec implementation and to evaluate the performance improvement derived from the proposed CLA. © 2008 IEEE
Network layer security: Design for a cross layer architecture
No full textTraditional modular layering schemes have served a major part in the development of a variety of protocols. However, as the physical layer impairments become more unpredictable, a cross layer design (CLD) which is dynamic in nature provides better performance. CLD introduces new challenges in protocol design as well as in the area of security. Using numerical analysis, we show that a link layer design employing header compression and cross layer signalling to protect protocol headers can limit packet discarding. This paper also reviews the IPsec protocol and describes how IPsec can be modified for cross layer architecture. © 2007 IEEE
The effect of the inhibition-compensation learning scheme on n-tuple based classifier performance
No full textThe inhibition-compensation learning scheme (ICLS) has been proposed as a way of enhancing the performance of the moving window classifier. In the paper the effect of ICLS on three n-tuple based classification techniques has been investigated. Pre-segmented handwritten characters from the NIST database have been used as the pattern data. Results show that approximately 2-6% gain in classification accuracy can be achieved in the OCR task domain with no adverse effect on the classification throughput
Toward 'socially constructive' social constructions of leadership
No full textIn their introductory editorial essay for this special issue, David Grant and Gail Fairhurst have done us a great service by valiantly producing a "Sailing Guide" to the Social Construction of Leadership (Fairhurst & Grant, 2010). As with rounding the Capes, this is not a task for the faint of heart. A sailing guide is designed to provide vital knowledge about a particular sea or coast, providing us with charts, warnings about potential hazards and an indication where we might find safe havens in a storm. Their sailing guide does this to great effect as it skilfully "boxes the compass" by revealing all of the potential directions that one might set one‟s sail by if one was sufficiently foolhardy to embark on a cruise of the social construction of leadership
Optimisation Procedures for Diagnostic Processing of Hand-drawn Geometric Figures
No full textAn investigation into task and feature selection for analysing diagnostic drawings using handwriting dynamics and image processing techniques is presented. Performance across a standard test battery and a subset selection process for both features and tasks is examined. It is shown that a reduced task domain provides results which can identify trends in patient performance at a higher accuracy than is obtainable when the whole feature/task set is used
Electrical and Mechanical Properties of new Recyclable Power Cable Insulation Materials based upon Polyethylene Blends
No full textChemically crosslinked polyethylene (XLPE) has been used as electrical insulation for power cables since the 1970s due to its favourable combination of electrical and mechanical properties. However, as the electrical engineering community has become increasingly aware of the life cycle environmental impacts, XLPE has come under scrutiny for its lack of recyclability and the high process energies used in its manufacture. Although technologies are being developed to facilitate the re-use of XLPE at the end of its initial service life, the use of this material is inferior to fully recyclable and low process energy alternatives. In this investigation, we concentrated on the use of binary blends of linear and branched polyethylene (LPE / BPE) as potential replacement materials for XLPE, since such systems have the potential to combine comparable mechanical properties and enhanced breakdown strength with good recyclability. We compare the thin film AC ramp breakdown behaviour of blends as a function of temperature up to 97 oC. These consist of the same BPE in virgin and crosslinked states and in a blend with 20wt% LPE. These data are augmented with dynamic mechanical analysis. In concert, these data indicate that with appropriate morphological control the blended thermoplastic material exhibits superior properties to XLPE under conventional operating conditions and may even be suitable for higher temperature operation than XLPE. The paper will discuss the importance of polymer blending and blend physical properties in the context of the process requirements and the implications for cable manufacture and on cable electrical and environmental performance in comparison with XLPE
Multimedia traffic scheduling in DVB-S2 networks with mobile users
No full textDVB-S2 is a second-generation standard for satellite transmissions, developed to improve the performance of DVB-S. Recently, research efforts have been devoted to extend this standard for mobile usage. In this paper we consider a scenario composed of a Ku-band GEO bent-pipe satellite, a gateway and some mobile users. The interest is here in investigating the performance of a scheduling scheme to manage DVB-S2 resources on the forward channel for the delivery of video CBR and FTP traffic flows to mobile users. A novel scheduler scheme, called UBMT, has been proposed that aims to manage CBR packet transmission deadlines while maximizing the aggregated goodput. Simulation runs have permitted to validate the optimal performance achieved by UBMT in comparison with other schemes. The impact of different TCP versions has been investigated as well showing the good results obtained with the SACK option
Automatic classification of hand drawn geometric shapes using constructional sequence analysis
No full text- …
