Introgression in interspecific hybrids of lily

In order to introduce new desirable characters into the cultivar assortment of lily a range of interspecific crossing barriers has to be overcome. By using various pollination and embryo rescue techniques pre- and postfertilization barriers were overcome and a range of wide interspecific lily hybrids between species and cultivars from the different sections of the genus Lilium could be made. Important breakthroughs include the development of the LA- (L. longiflorum x Asiatic hybrids), the LO- (L. longiflorum x Oriental hybrids) and the OA- (Oriental x Asiatic hybrids) hybrids. In general wide interspecific lily hybrids show F1-sterility. Using somatic chromosome doubling techniques (mitotic polyploidization) tetraploids with restored fertility can be produced from these diploid hybrids. An alternative method is the use of unreduced (or 2n) gametes (meiotic polyploidization), which are rarely found in some hybrids. Introgression of alien chromosome segments from donor species into recipient cultivar through backcrossing of F1 hybrid was studied using in situ hybridization techniques (GISH). Mitotic polyploidization showed no homoeologous recombinations between the parental genomes whereas meiotic polyploidization detected many. The use of 2n-gametes seems to be the most promising way for the introgression of desirable characters

Automatic generation of robot and manual assembly plans using octrees

This paper aims to investigate automatic assembly planning for robot and manual assembly. The octree decomposition technique is applied to approximate CAD models with an octree representation which are then used to generate robot and manual assembly plans. An assembly planning system able to generate assembly plans was developed to build these prototype models. Octree decomposition is an effective assembly planning tool. Assembly plans can automatically be generated for robot and manual assembly using octree models. Research limitations/implications - One disadvantage of the octree decomposition technique is that it approximates a part model with cubes instead of using the actual model. This limits its use and applications when complex assemblies must be planned, but in the context of prototyping can allow a rough component to be formed which can later be finished by hand. Assembly plans can be generated using octree decomposition, however, new algorithms must be developed to overcome its limitations

The Analysis of design and manufacturing tasks using haptic and immersive VR - Some case studies

The use of virtual reality in interactive design and manufacture has been researched extensively but the practical application of this technology in industry is still very much in its infancy. This is surprising as one would have expected that, after some 30 years of research commercial applications of interactive design or manufacturing planning and analysis would be widespread throughout the product design domain. One of the major but less well known advantages of VR technology is that logging the user gives a great deal of rich data which can be used to automatically generate designs or manufacturing instructions, analyse design and manufacturing tasks, map engineering processes and, tentatively, acquire expert knowledge. The authors feel that the benefits of VR in these areas have not been fully disseminated to the wider industrial community and - with the advent of cheaper PC-based VR solutions - perhaps a wider appreciation of the capabilities of this type of technology may encourage companies to adopt VR solutions for some of their product design processes. With this in mind, this paper will describe in detail applications of haptics in assembly demonstrating how user task logging can lead to the analysis of design and manufacturing tasks at a level of detail not previously possible as well as giving usable engineering outputs. The haptic 3D VR study involves the use of a Phantom and 3D system to analyse and compare this technology against real-world user performance. This work demonstrates that the detailed logging of tasks in a virtual environment gives considerable potential for understanding how virtual tasks can be mapped onto their real world equivalent as well as showing how haptic process plans can be generated in a similar manner to the conduit design and assembly planning HMD VR tool reported in PART A. The paper concludes with a view as to how the authors feel that the use of VR systems in product design and manufacturing should evolve in order to enable the industrial adoption of this technology in the future

Octree-based production of near net shape components

Near net shape (NNS) manufacturing refers to the production of products that require a finishing operation of some kind. NNS manufacturing is important because it enables a significant reduction in: machining work, raw material usage, production time, and energy consumption. This paper presents an integrated system for the production of near net shape components based on the Octree decomposition of 3-D models. The Octree representation is used to automatically decompose and approximate the 3-D models, and to generate the robot instructions required to create assemblies of blocks secured by adhesive. Not only is the system capable of producing shapes of variable precision and complexity (including overhanging or reentrant shapes) from a variety of materials, but it also requires no production tooling (e.g., molds, dies, jigs, or fixtures). This paper details how a number of well-known Octree algorithms for subdivision, neighbor findings, and tree traversal have been modified to support this novel application. This paper ends by reporting the construction of two mechanical components in the prototype cell, and discussing the overall feasibility of the system

Dynamic Bandwidth Allocation in Heterogeneous OFDMA-PONs Featuring Intelligent LTE-A Traffic Queuing

This work was supported by the ACCORDANCE project, through the 7th ICT Framework Programme. This is an Accepted Manuscript of an article accepted for publication in Journal of Lightwave Technology following peer review. © 2014 IEEE Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.A heterogeneous, optical/wireless dynamic bandwidth allocation framework is presented, exhibiting intelligent traffic queuing for practically controlling the quality-of-service (QoS) of mobile traffic, backhauled via orthogonal frequency division multiple access–PON (OFDMA-PON) networks. A converged data link layer is presented between long term evolution-advanced (LTE-A) and next-generation passive optical network (NGPON) topologies, extending beyond NGPON2. This is achieved by incorporating in a new protocol design, consistent mapping of LTE-A QCIs and OFDMA-PON queues. Novel inter-ONU algorithms have been developed, based on the distribution of weights to allocate subcarriers to both enhanced node B/optical network units (eNB/ONUs) and residential ONUs, sharing the same infrastructure. A weighted, intra-ONU scheduling mechanism is also introduced to control further the QoS across the network load. The inter and intra-ONU algorithms are both dynamic and adaptive, providing customized solutions to bandwidth allocation for different priority queues at different network traffic loads exhibiting practical fairness in bandwidth distribution. Therefore, middle and low priority packets are not unjustifiably deprived in favor of high priority packets at low network traffic loads. Still the protocol adaptability allows the high priority queues to automatically over perform when the traffic load has increased and the available bandwidth needs to be rationally redistributed. Computer simulations have confirmed that following the application of adaptive weights the fairness index of the new scheme (representing the achieved throughput for each queue), has improved across the traffic load to above 0.9. Packet delay reduction of more than 40ms has been recorded as a result for the low priority queues, while high priories still achieve sufficiently low packet delays in the range of 20 to 30msPeer reviewe

MAC Protocol Design for the Support of DBA in OFDMA-PON Networks

Wansu Lim, Ali Gliwan, Pandelis Kourtessis, Konstantinos Kanonakis, Ioannis Tomkos, John Senior, 'MAC Protocol Design for the Support of DBA in OFDMA-PON Networks', Paper presented at the Future Network and Mobile Summit, 15-17 June 2011, Warsaw, Poland.Original MAC frame formats have been developed to provide recommendations for new protocol designs in OFDMA-PONs. The portrayed scalability of the Dynamic Subcarrier Allocation (DScA) protocol is complemented by the granularity of hybrid OFDMA/TDMA topologies. Modelling of the DScA performance in OPNET has recorded the maximum 312.5 Mbits/s transmission rate capacity per ONU achieved at less than 2 ms packet delay and more than 95% network throughput depending on ONU offered load.Peer reviewe

Dynamic Subcarrier Allocation for 100 Gbps, 40 km OFDMA-PONs with SLA and CoS

This paper was published in Journal of Lightwave Technology and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/jlt/issue.cfm?volume=31&issue=7 Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under lawThe quality of service of 100Gbps orthogonal frequency division multiple access passive optical networks (OFDMA-PONs) performing dynamic bandwidth allocation is evaluated. New medium access control protocols and frame formats have been developed, exhibiting hybrid OFDMA/time division multiple access scheduling, for capacity enhancement and granular bandwidth allocation. The sequential dynamic subcarrier allocation algorithms allow the network optical line terminal to grant the optical network units (ONUs) bandwidth using both status and non-status based algorithm. Simulations of a 100 Gbps network with 256 ONUs, 256 subcarriers and 40 km extended-reach demonstrate best network throughputs of 87.5 Gbps and 3 ms packet delays for high priority service classes, even at maximum ONU load. In addition, high service level agreement (SLA) ONUs exhibit 1.56 Gbps maximum capacity and 48.82 kbps granularity.Peer reviewedFinal Accepted Versio

Comparison of SIVmac239(352–382) and SIVsmmPBj41(360–390) enterotoxic synthetic peptides

AbstractTo characterize the active domain of the simian immunodeficiency virus (SIV) surface unit (SU) enterotoxin, peptides corresponding to the V3 loop of SIVmac239 (SIVmac) and SIVsmmPBj41 (SIVpbj) were synthesized and examined for enterotoxic activity, α-helical structure, and interaction(s) with model membranes. SIVmac and SIVpbj induced a dose-dependent diarrhea in 6–8-day-old mouse pups similar to full-length SU. The peptides mobilized [Ca2+]i in HT-29 cells with distinct oscillations and elevated inositol triphosphate levels. Circular dichroism analyses showed the peptides were predominantly random coil in buffer, but increased in α-helical content when placed in a hydrophobic environment or with cholesterol-containing membrane vesicles that are rich in anionic phospholipids. None of the peptides underwent significant secondary structural changes in the presence of neutral vesicles indicating ionic interactions were important. These data show that the SIV SU enterotoxic domain localizes in part to the V3 loop region and interacts with anionic membrane domains on the host cell surface

An explorative study of interface support for image searching

In this paper we study interfaces for image retrieval systems. Current image retrieval interfaces are limited to providing query facilities and result presentation. The user can inspect the results and possibly provide feedback on their relevance for the current query. Our approach, in contrast, encourages the user to group and organise their search results and thus provide more fine-grained feedback for the system. It combines the search and management process, which - according to our hypothesis - helps the user to onceptualise their search tasks and to overcome the query formulation problem. An evaluation, involving young design-professionals and di®erent types of information seeking scenarios, shows that the proposed approach succeeds in encouraging the user to conceptualise their tasks and that it leads to increased user satisfaction. However, it could not be shown to increase performance. We identify the problems in the current setup, which when eliminated should lead to more effective searching overall