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Showing papers in "Science & Engineering Faculty in 2008"


Journal Article
TL;DR: This paper proposes a mapping from BPMN to a formal language, namely Petri nets, for which efficient analysis techniques are available and has been implemented as a tool that, in conjunction with existing Petri net-based tools, enables the static analysis of BPMn models.
Abstract: The Business Process Modelling Notation (BPMN) is a standard for capturing business processes in the early phases of system development. The mix of constructs in BPMN makes it possible to define models with a range of semantic errors. But the static analysis of BPMN models to detect such errors is hindered by ambiguities in the standard specification and the complexity of the language. The fact that BPMN integrates constructs from graph-oriented process definition languages with features for concurrent execution of multiple instances of a subprocess and exception handling, makes it challenging to provide a formal semantics of BPMN. Even more challenging is to provide a semantics that can be used to analyse BPMN models. This paper proposes a formalisation of BPMN in terms a mapping to Petri nets, for which efficient analysis techniques exist. The mapping has been implemented as a tool that generates code in the Petri Net Markup Language. The formalisation has led to the identification of deficiencies in the BPMN specification.

540 citations


Journal Article
TL;DR: In this article, a comprehensive review of the state-of-the-art research activities in the field of inorganic semiconductor nanostructures is presented, which mainly focuses on the most widely studied inorganic nano-structures, such as ZnO, ZnS, Si, WO3, AlN, SiC and their field-emission properties.
Abstract: Inorganic semiconductor nanostructures are ideal systems for exploring a large number of novel phenomena at the nanoscale and investigating the size and dimensionality dependence of their properties for potential applications. The use of such nanostructures with tailored geometries as building blocks is also expected to play crucial roles in future nanodevices. Since the discovery of carbon nanotubes much attention has been paid to exploring the usage of inorganic semiconductor nanostructures as field-emitters due to their low work functions, high aspect ratios and mechanical stabilities, and high electrical and thermal conductivities. This article provides a comprehensive review of the state-of-the-art research activities in the field. It mainly focuses on the most widely studied inorganic nanostructures, such as ZnO, ZnS, Si, WO3, AlN, SiC, and their field-emission properties. We begin with a survey of inorganic semiconductor nanostructures and the field-emission principle, and then discuss the recent progresses on several kinds of important nanostructures and their field-emission characteristics in detail and overview some additional inorganic semiconducting nanomaterials in short. Finally, we conclude this review with some perspectives and outlook on the future developments in this area.

528 citations


Journal Article
TL;DR: RNA silencing has become a major focus of molecular biology and biomedical research around the world as mentioned in this paper, highlighted by a simple PubMed search for RNA silencing, which retrieves almost 9,000 articles.
Abstract: RNA silencing has become a major focus of molecular biology and biomedical research around the world. This is highlighted by a simple PubMed search for “RNA silencing,” which retrieves almost 9,000 articles. Interest in gene silencing-related mechanisms stemmed from the early 1990s, when this phenomenon was first noted as a surprise observation by plant scientists during the course of plant transformation experiments, in which the introduction of a transgene into the genome led to the silencing of both the transgene and homologous endogenes. From these initial studies, plant biologists have continued to generate a wealth of information into not only gene silencing mechanisms but also the complexity of these biological pathways as well as revealing their multilevel interactions with one another. The plant biology community has also made significant advancements in exploiting RNA silencing as a powerful tool for gene function studies and crop improvements. In this article, we (1) review the rich history of gene silencing research and the knowledge it has generated into our understanding of this fundamental mechanism of gene regulation in plants; (2) describe examples of the current applications of RNA silencing in crop plants; and (3) discuss improvements in RNA silencing technology and its potential application in plant science.

283 citations


Journal Article
TL;DR: Grostl is a SHA-3 candidate proposal, an iterated hash function with a compression function built from two fixed, large, distinct permutations, which has the effect that all known, generic attacks on the hash function are made much more difficult.
Abstract: Grostl is a SHA-3 candidate proposal. Grostl is an iterated hash function with a compression function built from two fixed, large, distinct permutations. The design of Grostl is transparent and based on principles very different from those used in the SHA-family. The two permutations are constructed using the wide trail design strategy, which makes it possible to give strong statements about the resistance of Grostl against large classes of cryptanalytic attacks. Moreover, if these permutations are assumed to be ideal, there is a proof for the security of the hash function. Grostl is a byte-oriented SP-network which borrows components from the AES. The S-box used is identical to the one used in the block cipher AES and the diffusion layers are constructed in a similar manner to those of the AES. As a consequence there is a very strong confusion and diffusion in Grostl. Grostl is a so-called wide-pipe construction where the size of the internal state is significantly larger than the size of the output. This has the effect that all known, generic attacks on the hash function are made much more difficult. Grostl has good performance on a wide range of platforms and counter-measures against side-channel attacks are well-understood from similar work on the AES.

246 citations


Journal Article
TL;DR: In this article, a controlled synthesis of two novel semiconducting heterostructures: heterocrystalline ZnS/ZnO biaxial nanobelts via a simple one-step thermal evaporation method is reported.
Abstract: We report on a controlled synthesis of two novel semiconducting heterostructures: heterocrystalline-ZnS/single-crystalline-ZnO biaxial nanobelts and side-to-side single-crystalline ZnS/ZnO biaxial nanobelts via a simple one-step thermal evaporation method. In the first heterostructure, a ZnS domain is composed of the heterocrystalline superlattice (3C-ZnS) N /(2H-ZnS) M [111]-[0001] with the atomically smooth interface between wurtzite and zinc blende ZnS fragments. High-spatial resolution cathodoluminescence studies on individual heterostructures for the first time reveal a new ultraviolet emission peak ( approximately 355 nm), which is not observed in separate ZnS or ZnO nanostructures. The present hererostructures are expected to become valuable not only with respect to fundamental research but also for a design of new broad-range ultraviolet nanoscale lasers and sensors.

162 citations


Journal Article
TL;DR: In this article, the phase instability beyond a critical Al content was attributed to occupation of the Ti-Al anti-bonding orbital, which reduces the coupling strength between Ti(2)C slab and Al atomic plane.
Abstract: Ti(2)AlC was predicted to bear Al-vacancy down to a sub-stoichiometry of Ti(2)Al(0.5)C. The phase instability beyond a critical Al content was attributed to occupation of the Ti-Al anti-bonding orbital, which reduces the coupling strength between Ti(2)C slab and Al atomic plane. The migration energy barrier of Al self-diffusion along the (0001) plane was low, 0.83 eV, resulting in rapid out-diffusion of Al during oxidation and decomposition of Ti(2)AlC at high temperatures. (c) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

112 citations


Journal Article
TL;DR: The surface plasmon resonance (SPR) effects of embedded Au nanoparticles are proposed to be responsible for the remarkable photoresponse of these novel structures made of twinned Ga2O3 nanowires embedding discrete gold particles along the twin boundary.
Abstract: A novel metal-insulator heterostructure made of twinned Ga2O3 nanowires embedding discrete gold particles along the twin boundary was formed through a reaction between gold, gallium, and silica at 800 degrees C during simple thermal annealing. The Au-in-Ga2O3 peapods spontaneously crystallized under phase separation induced by the formation of twin boundaries. The nanostructures were analyzed by field emission scanning (FESEM) and transmission electron microscopes (FETEM), and their photoresponse was investigated using a double-frequency Nd:YAG laser with a wavelength of 532 nm on a designed single-nanowire device. The surface plasmon resonance (SPR) effects of embedded Au nanoparticles are proposed to be responsible for the remarkable photoresponse of these novel structures.

101 citations


Journal Article
TL;DR: In this paper, the authors use information gap decision theory to find strategies for maximizing the number of extant subpopulations of a threatened species that are most immune to failure due to model uncertainty.
Abstract: 1. In conservation decision-making, we operate within the confines of limited funding. Furthermore, we often assume particular relationships between management impact and our investment in management. The structure of these relationships, however, is rarely known with certainty - there is model uncertainty. We investigate how these two fundamentally limiting factors in conservation management, money and knowledge, impact optimal decision-making. 2. We use information-gap decision theory to find strategies for maximizing the number of extant subpopulations of a threatened species that are most immune to failure due to model uncertainty. We thus find a robust framework for exploring optimal decision-making. 3. The performance of every strategy decreases as model uncertainty increases. 4. The strategy most robust to model uncertainty depends not only on what performance is perceived to be acceptable but also on available funding and the time horizon over which extinction is considered. 5. Synthesis and applications. We investigate the impact of model uncertainty on robust decision-making in conservation and how this is affected by available conservation funding. We show that subpopulation triage can be a natural consequence of robust decision-making. We highlight the need for managers to consider triage not as merely giving up, but as a tool for ensuring species persistence in light of the urgency of most conservation requirements, uncertainty and the poor state of conservation funding. We illustrate this theory by a specific application to allocation of funding to reduce poaching impact on the Sumatran tiger Panthera tigris sumatrae in Kerinci Seblat National Park. © 2008 The Authors.

92 citations


Journal Article
TL;DR: In this paper, the geometries, formation energies, electronic properties, and reactivities of single-walled (8,0) boron nitride nanotubes (BNNTs) were investigated by means of gradient-corrected density functional theory (DFT) computations.
Abstract: The geometries, formation energies, electronic properties, and reactivities of Stone−Wales (SW) defects in single-walled (8,0) boron nitride nanotubes (BNNTs) were investigated by means of gradient-corrected density functional theory (DFT) computations. SW defects deform BNNTs severely and result in local curvature changes at defect sites. The energies of defect formation increase with increasing tube diameters and are orientation dependent. Depending on the SW defect orientations, additions to central 7-7 ring fusions can be either more or less favorable than to defect-free sites. The reaction energies of model H2 addition are mostly endothermic for defective as well as pristine BNNTs, but reactions at the most favorable sites near SW defect (homoelement N−N bonds followed by the B−B bond sites) are exothermic. This and the fact that the band structures of BNNTs are only slightly changed by SW and vacancy defects as well as by chemical additions at low modification ratios endow BNNTs with great applicati...

88 citations


Journal Article
TL;DR: The Business Process Modeling Notation (BPMN) is an increasingly important standard for process modeling and has enjoyed high levels of attention and uptake in BPM practice, according to a global survey of BPMN process modelers conducted during May to August 2007.
Abstract: The Business Process Modeling Notation (BPMN) is an increasingly important standard for process modeling and has enjoyed high levels of attention and uptake in BPM practice. This paper reports on a global survey of BPMN process modelers conducted during May to August 2007. Five hundred and ninety BPMN modelers responded and provided insights into the who, where, how and why of BPMN process modeling as well as into some of the problems users experience when modeling with BPMN.

87 citations


Journal Article
TL;DR: This paper proposes an automated approach for querying a business process model repository for structurally and semantically relevant models and provides abusiness process model search engine implementation for evaluation of the proposed approach.
Abstract: Determining similarity between business process models has recently gained interest in the business process management community. So far similarity was addressed separately either at semantic or structural aspect of process models. Also, most of the contributions that measure similarity of process models assume an ideal case when process models are enriched with semantics - a description of meaning of process model elements. However, in real life this results in a heavy human effort consuming pre-processing phase which is often not feasible. In this paper we propose an automated approach for querying a business process model repository for structurally and semantically relevant models. Similar to the search on the Internet, a user formulates a BPMN-Q query and as a result receives a list of process models ordered by relevance to the query. We provide a business process model search engine implementation for evaluation of the proposed approach.

Journal Article
TL;DR: In this paper, the authors present a staged approach to the development of kimberlite terminology, where descriptive terminology is developed first, followed by application of genetic terminology once all features, including the effects of alteration on original texture and depositional features, together with contact relationships and setting, have been evaluated.
Abstract: Although kimberlite pipes/bodies are usually the remains of volcanic vents, in-vent deposits, and subvolcanic intrusions, the terminology used for kimberlite rocks has largely developed independently of that used in mainstream volcanology. Existing kimberlite terminology is not descriptive and includes terms that are rarely used, used differently, and even not used at all in mainstream volcanology. In addition, kimberlite bodies are altered to varying degrees, making application of genetic terminology difficult because original components and depositional textures are commonly masked by alteration. This paper recommends an approach to the terminology for kimberlite rocks that is consistent with usage for other volcanic successions. In modern terrains the eruption and emplacement origins of deposits can often be readily deduced, but this is often not the case for old, variably altered and deformed rock successions. A staged approach is required whereby descriptive terminology is developed first, followed by application of genetic terminology once all features, including the effects of alteration on original texture and depositional features, together with contact relationships and setting, have been evaluated. Because many volcanic successions consist of both primary volcanic deposits as well as volcanic sediments, terminology must account for both possibilities.

Journal Article
TL;DR: Novel and highly porous boron nitride (BN) nanospheres that exhibit a rough surface consisting of open BN nanocones and corrugated BN ribbons are synthesised that behave like metals as confirmed by first-principles calculations.
Abstract: We first describe the synthesis of novel and highly porous boron nitride (BN) nanospheres (100-400 nm o.d.) that exhibit a rough surface consisting of open BN nanocones and corrugated BN ribbons. The material was produced by reacting B2O3 with nanoporous carbon spheres under nitrogen at ca. 1750 degrees C. The BN nanospheres were characterized using scanning electron microscopy, high-resolution electron microscopy, and electron energy loss spectroscopy. The porous BN spheres show relatively large surface areas of ca. 290 m2/g and exhibit surprisingly stable field emission properties at low turn-on voltages (e.g., 1-1.3 V/microm). We attribute these outstanding electron emission properties to the presence of finite BN ribbons located at the surface of the nanospheres (exhibiting zigzag edges), which behave like metals as confirmed by first-principles calculations. In addition, our ab initio theoretical results indicate that the work function associated to these zigzag BN ribbons is 1.3 eV lower when compared with BN-bulk material.

Journal Article
TL;DR: A short signature scheme that is strongly existentially unforgeable under an adaptive chosen message attack in the standard security model and a tight reduction proving that the scheme is secure in any group in which the SDH assumption holds, without relying on the random oracle model.
Abstract: We describe a short signature scheme that is strongly existentially unforgeable under an adaptive chosen message attack in the standard security model. Our construction works in groups equipped with an efficient bilinear map, or, more generally, an algorithm for the Decision Diffie-Hellman problem. The security of our scheme depends on a new intractability assumption we call Strong Diffie-Hellman (SDH), by analogy to the Strong RSA assumption with which it shares many properties. Signature generation in our system is fast and the resulting signatures are as short as DSA signatures for comparable security. We give a tight reduction proving that our scheme is secure in any group in which the SDH assumption holds, without relying on the random oracle model.

Journal Article
TL;DR: In this article, the practical benefits and drawbacks of several identity-based encryption schemes based on bilinear pairings are surveyed and compared, and the strengths and weaknesses of each construction according to a few theoretical and many applied comparison criteria.
Abstract: This paper surveys the practical benefits and drawbacks of several identity-based encryption schemes based on bilinear pairings. After providing some background on identity-based cryptography, we classify the known constructions into a handful of general approaches. We then describe efficient and fully secure IBE and IBKEM instantiations of each approach, with reducibility to practice as the main design parameter. Finally, we catalogue the strengths and weaknesses of each construction according to a few theoretical and many applied comparison criteria.

Journal Article
TL;DR: Six new whole mitochondrial genomes from wild-caught specimens from four species of Rattus, placing the deepest divergence within Rattus at approximately 3.5 million years ago, give both a better resolved species divergence order and diversification dates inside Rattus than previous studies.
Abstract: The timing and order of divergences within the genus Rattus have, to date, been quite speculative. In order to address these important issues we sequenced six new whole mitochondrial genomes from wild-caught specimens from four species, Rattus exulans, Rattus praetor, Rattus rattus and Rattus tanezumi. The only rat whole mitochondrial genomes available previously were all from Rattus norvegicus specimens. Our phylogenetic and dating analyses place the deepest divergence within Rattus at ∼3.5 million years ago (Mya). This divergence separates the New Guinean endemic R. praetor lineage from the Asian lineages. Within the Asian/Island Southeast Asian clade R. norvegicus diverged earliest at ∼2.9 Mya. R. exulans and the ancestor of the sister species R. rattus and R. tanezumi subsequently diverged at ∼2.2 Mya, with R. rattus and R. tanezumi separating as recently as ∼0.4 Mya. Our results give both a better resolved species divergence order and diversification dates within Rattus than previous studies.

Journal Article
TL;DR: A Business Goal Ontology is designed for modeling business goals and a modeling pattern for linking the goals to process models is devised and it is shown how the ontology can be used in query answering.
Abstract: Broad knowledge is required when a business process is modeled by a business analyst. We argue that existing Business Process Management methodologies do not consider business goals at the appropriate level. In this paper we present an approach to integrate business goals and business process models. We design a Business Goal Ontology for modeling business goals. Furthermore, we devise a modeling pattern for linking the goals to process models and show how the ontology can be used in query answering. In this way, we integrate the intentional perspective into our business process ontology framework, enriching the process description and enabling new types of business process analysis. © 2008 IEEE.

Journal Article
TL;DR: In this paper, an ensemble of multilayer boron nitride nanotubes with diameters from 30 nm to 110 nm is studied and the results are compared with the related bulk material, hexagonal BN.
Abstract: Individual multiwall boron nitride nanotubes with diameters from 30 nm to 110 nm are shown to be efficient UV emitters by cathodoluminescence. Their luminescence does not evolve much in this diameter range, with dominant UV recombinations at about 230 nm. As a result, single nanotube properties can be obtained from experiments performed on ensembles of nanotubes. Such ensembles are studied by photoluminescence as a function of temperature 5 K‐300 K and by photoluminescence excitation experiments at 9 K. The results are discussed and compared with the related bulk material, hexagonal boron nitride. The strong luminescence recorded around 230 nm is attributed to excitonic effects, more precisely to excitons bound to the structural defects: dislocations, facets, which are observed along the walls.

Journal Article
TL;DR: In this article, the authors conducted an in-depth analysis of three of the major open source workflow management systems -jBPM, OpenWFE and Enhydra Shark, the results of which are reported here.
Abstract: In keeping with the proliferation of free software development initiatives and the increased interest in the business process management domain, many open source workflow and business process management systems have appeared during the last few years and are now under active development. This upsurge gives rise to two important questions: what are the capabilities of these systems? and how do they compare to each other and to their closed source counterparts? i.e. in other words what is the state-of-the-art in the area?. To gain an insight into the area, we have conducted an in-depth analysis of three of the major open source workflow management systems - jBPM, OpenWFE and Enhydra Shark, the results of which are reported here. This analysis is based on the workflow patterns framework and provides a continuation of the series of evaluations performed using the same framework on closed source systems, business process modeling languages and web-service composition standards. The results from evaluations of the three open source systems are compared with each other and also with the results from evaluations of three representative closed source systems - Staffware, WebSphere MQ and Oracle BPEL PM, documented in earlier works. The overall conclusion is that open source systems are targeted more toward developers rather than business analysts. They generally provide less support for the patterns than closed source systems, particularly with respect to the resource perspective which describes the various ways in which work is distributed amongst business users and managed through to completion.

Journal Article
TL;DR: In this article, a distributed data fusion (DDF) algorithm for consistent joint localisation and tracking of multiple targets in wireless sensor networks is presented, where particle representations of the state posteriors are communicated.
Abstract: This paper presents algorithms for consistent joint localisation and tracking of multiple targets in wireless sensor networks under the decentralised data fusion (DDF) paradigm where particle representations of the state posteriors are communicated. This work differs from previous work as more generalised methods have been developed to account for correlated estimation errors that arise due to common past information between two discrete particle sets. The particle sets are converted to continuous distributions for communication and inter-nodal fusion. Common past information is then removed by a division operation of two estimates so that only new information is updated at the node. In previous work, the continuous distribution used was limited to a Gaussian kernel function. This new method is compared to the optimal centralised solution where each node sends all observation information to a central fusion node when received. Results presented include a real-time application of the DDF operation of division on data logged from field trials.

Journal Article
TL;DR: Choreographien are introduced as an important artifact for SOA, compares them to service orchestrations and surveys existing languages for modeling them.
Abstract: Service oriented architecture (SOA) is an architectural style for building software systems based on services. Especially in those scenarios where services implement business processes, complex conversations between the services occur. Service choreographies are a means to capture all interaction obligations and constraints from a global perspective. This article introduces choreographies as an important artifact for SOA, compares them to service orchestrations and surveys existing languages for modeling them.

Journal Article
TL;DR: In this paper, the authors combined experimental and numerical results suggest that nonequilibrium plasma-driven self-organization leads to better size and positional uniformity of nickel nanodot arrays on a Si(100) surface compared with neutral gas-based processes under similar conditions.
Abstract: The results of the combined experimental and numerical study suggest that nonequilibrium plasma-driven self-organization leads to better size and positional uniformity of nickel nanodot arrays on a Si(100) surface compared with neutral gas-based processes under similar conditions. This phenomenon is explained by introducing the absorption zone patterns, whose areas relative to the small nanodot sizes become larger when the surface is charged. Our results suggest that strongly nonequilibrium and higher-complexity plasma systems can be used to improve ordering and size uniformity in nanodot arrays of various materials, a common and seemingly irresolvable problem in self-organized systems of small nanoparticles. © 2008 American Institute of Physics.

Journal Article
TL;DR: In this article, the stability and associated bifurcations of several types of pulse solutions in a singularly perturbed three-component reaction-diffusion equation were analyzed.
Abstract: In this article, we analyze the stability and the associated bifurcations of several types of pulse solutions in a singularly perturbed three-component reaction-diffusion equation that has its origin as a model for gas discharge dynamics. Due to the richness and complexity of the dynamics generated by this model, it has in recent years become a paradigm model for the study of pulse interactions. A mathematical analysis of pulse interactions is based on detailed information on the existence and stability of isolated pulse solutions. The existence of these isolated pulse solutions is established in previous work. Here, the pulse solutions are studied by an Evans function associated to the linearized stability problem. Evans functions for stability problems in singularly perturbed reaction-diffusion models can be decomposed into a fast and a slow component, and their zeroes can be determined explicitly by the NLEP method. In the context of the present model, we have extended the NLEP method so that it can be applied to multi-pulse and multi-front solutions of singularly perturbed reaction-diffusion equations with more than one slow component. The brunt of this article is devoted to the analysis of the stability characteristics and the bifurcations of the pulse solutions. Our methods enable us to obtain explicit, analytical information on the various types of bifurcations, such as saddle-node bifurcations, Hopf bifurcations in which breathing pulse solutions are created, and bifurcations into travelling pulse solutions, which can be both subcritical and supercritical.

Journal Article
TL;DR: In this article, the authors report on the fabrication of hydrogenated amorphous silicon carbide (a-Si1-xCx : H) films with different carbon contents at high deposition rates using inductively coupled plasma (ICP) chemical vapour deposition.
Abstract: It is commonly believed that in order to synthesize high-quality hydrogenated amorphous silicon carbide (a-Si1-xCx : H) films at competitive deposition rates it is necessary to operate plasma discharges at high power regimes and with heavy hydrogen dilution. Here we report on the fabrication of hydrogenated amorphous silicon carbide films with different carbon contents x (ranging from 0.09 to 0.71) at high deposition rates using inductively coupled plasma (ICP) chemical vapour deposition with no hydrogen dilution and at relatively low power densities (∼0.025 W cm -3) as compared with existing reports. The film growth rate R d peaks at x = 0.09 and x = 0.71, and equals 18 nm min-1 and 17 nm min-1, respectively, which is higher than other existing reports on the fabrication of a-Si1-xCx : H films. The extra carbon atoms for carbon-rich a-Si1-xCx : H samples are incorporated via diamond-like sp3 C-C bonding as deduced by Fourier transform infrared absorption and Raman spectroscopy analyses. The specimens feature a large optical band gap, with the maximum of 3.74 eV obtained at x = 0.71. All the a-Si1-xCx : H samples exhibit low-temperature (77 K) photoluminescence (PL), whereas only the carbon-rich a-Si1-xCx : H samples (x ≥ 0.55) exhibit room-temperature (300 K) PL. Such behaviour is explained by the static disorder model. High film quality in our work can be attributed to the high efficiency of the custom-designed ICP reactor to create reactive radical species required for the film growth. This technique can be used for a broader range of material systems where precise compositional control is required. © 2008 IOP Publishing Ltd.

Journal Article
TL;DR: In this paper, the intrinsic migration energies of various vacancies were determined to be in the sequence E m (V Al ) m ( V Ti ) m(V C ), where V Ti has the highest formation energy at all possible conditions.
Abstract: We performed ab initio calculations for monovacancy formation and migration in Ti 2 AlC. Carbon and aluminum vacancies have almost equally low formation energies, respectively, at (Ti- and Al-rich) and (Ti- and C-rich) growth conditions, wherein both defects exhibit a high equilibrium concentration and structural tolerance to large off-stoichiometry in Ti 2 AlC. In contrast, V Ti has the highest formation energy at all possible conditions. The intrinsic migration energies of various vacancies are determined to be in the sequence E m (V Al ) m (V Ti ) m (V C ).

Journal Article
TL;DR: This paper describes the development of a novel vision-based autonomous surface vehicle with the purpose of performing coordinated docking manoeuvres with a target, such as an autonomous underwater vehicle, at the water's surface.
Abstract: This paper describes the development of a novel vision-based autonomous surface vehicle with the purpose of performing coordinated docking manoeuvres with a target, such as an autonomous underwater vehicle, at the water's surface. The system architecture integrates two small processor units; the first performs vehicle control and implements a virtual force based docking strategy, with the second performing vision-based target segmentation and tracking. Furthermore, the architecture utilises wireless sensor network technology allowing the vehicle to be observed by, and even integrated within an ad-hoc sensor network. Simulated and experimental results are presented demonstrating the autonomous vision- based docking strategy on a proof-of-concept vehicle.

Journal Article
TL;DR: In this article, the synthesis of zigzag-shaped single-crystalline or twinned Zn3P2 nanowires via a thermochemical method was described, and the results showed that these unusual structures are p-type semiconductors and that the thermal activation with a 49.7 meV energy is the dominant transport mechanism.
Abstract: We describe the synthesis of zigzag-shaped single-crystalline or twinned Zn3P2 nanowires via a thermochemical method. The single-crystalline nanowires possessed two different kinds of kink angles and were formed via a vapor−solid process by using ZnS and GaP as source materials, whereas the twinned nanowires were synthesized via a vapor−liquid−solid process under additional introduction of In2S3 nanoparticles as the catalyst precursors. The products were characterized in detail by using X-ray diffraction, a scanning electron microscope, and a transmission electron microscope equipped with an energy-dispersive X-ray spectrometer. Field-effect transistors based on individual zigzag nanowires were fabricated and their electronic transport at different temperatures was analyzed. The results showed that these unusual structures are p-type semiconductors and that the thermal activation with a 49.7 meV energy is the dominant transport mechanism.

Journal Article
TL;DR: In this article, it was shown that Ni nanoparticles used as catalyst for vertically aligned carbon nanotube and nanocone arrays can be improved in low-temperature plasma- or ion-assisted processes compared with neutral gas-based routes.
Abstract: It is shown that the simultaneous saturation of Ni nanoparticles used as catalyst for vertically aligned carbon nanotube and nanocone arrays can be improved in low-temperature plasma- or ion-assisted processes compared with neutral gas-based routes. The results of hybrid multiscale numerical simulations of the catalyst nanoarrays (particle sizes of 2 and 10 nm) saturation with carbon show the possibility of reducing the difference in catalyst incubation times for smallest and largest catalyst particles by up to a factor of 2. This approach is generic and provides process conditions for simultaneous nucleation and growth of uniform arrays of vertically aligned nanostructures. © 2008 American Institute of Physics.

Book ChapterDOI
TL;DR: In this paper, the authors discuss the importance of services, the need for innovation, changes in consumer and business markets, and the advancements in information and communication technology (ICT) in the western economies.
Abstract: Western economies are highly dependent on service innovation for their growth and employment. An important driver for economic growth is, therefore, the development of new, innovative services like electronic services, mobile end-user services, new financial or personalized services. Service innovation joins four trends that currently shape the western economies: the growing importance of services, the need for innovation, changes in consumer and business markets, and the advancements in information and communication technology (ICT).

Journal Article
TL;DR: A novel synthesis technique via a heat expulsion mechanism was employed to prepare a 40 mL methacrylate monolith with a homogeneous radial pore structure along its thickness, which demonstrated rapid separation ability by fractionating Escherichia coli DH5alpha-pUC19 clarified lysate in only 3 min after loading.
Abstract: The extent of exothermicity associated with the construction of large-volume methacrylate monolithic columns has somewhat obstructed the realisation of large-scale rapid biomolecule purification especially for plasmid-based products which have proven to herald future trends in biotechnology. A novel synthesis technique via a heat expulsion mechanism was employed to prepare a 40 mL methacrylate monolith with a homogeneous radial pore structure along its thickness. Radial temperature gradient was recorded to be only 1.8 °C. Maximum radial temperature recorded at the centre of the monolith was 62.3 °C, which was only 2.3 °C higher than the actual polymerisation temperature. Pore characterisation of the monolithic polymer showed unimodal pore size distributions at different radial positions with an identical modal pore size of 400 nm. Chromatographic characterisation of the polymer after functionalisation with amino groups displayed a persistent dynamic binding capacity of 15.5 mg of plasmid DNA/mL. The maximum pressure drop recorded was only 0.12 MPa at a flow rate of 10 mL/min. The polymer demonstrated rapid separation ability by fractionating Escherichia coli DH5α-pUC19 clarified lysate in only 3 min after loading. The plasmid sample collected after the fast purification process was tested to be a homogeneous supercoiled plasmid with DNA electrophoresis and restriction analysis.