Consistency Maintenance of Group/Ungroup Operations in Object-based Collaborative Graphical Editing Systems

In real-time collaborative graphical editing systems, Object-based Group/Ungroup operations are frequently accessible and practically useful. However, the existing research on these operations of the graphical editing is rare and defective. In this paper, based on Multi-Version strategy and Address Space Transformation method, a new MVSDR algorithm, which is not only applied to simple operations (such as Create, Delete, ChangeATT, etc.), but also suitable for Group/Ungroup ones, is proposed to solve the consistency maintenance problem. The proposed algorithm abandons previous attempts to divide conflict operations into Real-Conflict operations and Resolvable-Conflict ones and to deal with them separately, thus making the algorithm more simple and effective. In addition, an example analysis is also given in this paper to prove the algorithm’s correctness and effectiveness

High Efficient Consistency Maintenance Strategy of Real-time String Text Editing Systems

Replicated architecture is widely used in the field of real-time collaborative text editor. The idea of address space transformation provides a new way for concurrency control. During concurrent processing, it retraces the document status back to the state when the operations are generated to maintain consistency. However the previous concurrency processes strategy is based on single characters, the transmission cost during processing is too high since every character is packaged and broadcasted to remote sites after they are created by local site. When the network load is high, especially when the network is unstable, this shortage will be even more obvious. Due to this problem, this paper presents a consistency maintenance strategy based on string editing operations, and proposes the string splitting mechanism combined with the idea of the address space transformation in order to maintain consistency. This strategy increases the transmission efficiency while guaranteeing the consistency of the shared document

Anisotropic mechanical behavior of thermally bonded nonwoven fabric

Anisotropic properties of thermally bonded nonwoven fabric (polypropylene) have been investigated. Firstly, the orientation distribution function of fibre is obtained by applying Hough transform technique to scanning electron microscopy of nonwoven fabric. Secondly, the influence of specimen width on mechanical behavior of nonwoven fabric has been studied, and the relationships between tensile strength of nonwoven fabric and specimen width are acquired by applying nonlinear fitting. Finally, the anisotropic creep behavior of nonwoven is investigated at different stress levels, different directions of nonwoven and different durations by applying nonlinear fitting, and the empirical model for calculating creep elongation is deduced. The results show that the tensile and creep behaviors of nonwoven fabric are influenced significantly by the fibre distribution. The creep elongation of nonwoven fabric is proportional to the level of loading and time. The creep elongation of nonwoven fabrics follows exponential relationships with time and this is true for all the directions of load and for all the levels of loading

An exploration of L2 listening problems and their causes

Listening has long been recognised as the most challenging skill for teachers, students and researchers working in the context of L2 English. However, it has also been the least researched of the four language skills, and one that has received the least attention in second language acquisition. This study identified the listening problems, and their causes, experienced by Chinese university students at intermediate level through multiple perspectives. Included in the investigation were learners’ perceptions, their performance in phonological vocabulary tests and their recognition of words from dictation transcription in terms of lexical processing and spoken word recognition, in addition to learners’ self-reflection and the teacher’s reflection after one-semester of instruction and learning. The ultimate aims of the study were to contribute to our understanding of the nature of listening comprehension and the causes of the difficulties it poses for these learners in order to advance a research-based pedagogy to help them improve their listening comprehension skills. A mixed methods approach was employed, integrating questionnaire surveys, participants’ self-reflections, the Aural-Lex tests, and dictation transcriptions conducted both at the very beginning and at the end of the semester. Findings suggest that the main difficulties and the causes of these difficulties in listening comprehension for Chinese university students at intermediate level include the following: limited knowledge of phonology, inadequate vocabulary by sound, and poor awareness of the features of connected speech. The study suggests that Chinese university students at this level need to improve their spoken word recognition and develop an awareness of the organisation of sounds in English connected speech, as these cognitive processes play a vital role in proficient listening comprehension. Similarly, it proposes that researchers and teachers working in higher education in the L2 context should work closely together to address intermediate learners’ needs and difficulties, both theoretically and practically, in order to help them enhance their listening comprehension skills

NANOCOMPOSITES OF POLY(LACTIC ACID) REINFORCED WITH CELLULOSE NANOFIBRILS

A chemo-mechanical method was used to prepare cellulose nanofibrils dispersed uniformly in an organic solvent. Poly(ethylene glycol) (PEG 1000) was added to the matrix as a compatibilizer to improve the interfacial interaction between the hydrophobic poly(lactic acid) (PLA) and the hydrophilic cellulose nanofibrils. The composites obtained by solvent casting methods from N,N-Dimethylacetamide (DMAc) were characterized by tensile testing machine, atomic force microscope (AFM), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FT-IR). The tensile test results indicated that, by adding PEG to the PLA and the cellulose nanofibrils matrix, the tensile strength and the elongation rate increased by 56.7% and 60%, respectively, compared with the PLA/cellulose nanofibrils composites. The FT-IR analysis successfully showed that PEG improved the intermolecular interaction, which is based on the existence of inter-molecular hydrogen bonding among PLA, PEG, and cellulose nanofibrils

An exploration of L2 listening problems and their causes

Listening has long been recognised as the most challenging skill for teachers, students and researchers working in the context of L2 English. However, it has also been the least researched of the four language skills, and one that has received the least attention in second language acquisition. This study identified the listening problems, and their causes, experienced by Chinese university students at intermediate level through multiple perspectives. Included in the investigation were learners’ perceptions, their performance in phonological vocabulary tests and their recognition of words from dictation transcription in terms of lexical processing and spoken word recognition, in addition to learners’ self-reflection and the teacher’s reflection after one-semester of instruction and learning. The ultimate aims of the study were to contribute to our understanding of the nature of listening comprehension and the causes of the difficulties it poses for these learners in order to advance a research-based pedagogy to help them improve their listening comprehension skills. A mixed methods approach was employed, integrating questionnaire surveys, participants’ self-reflections, the Aural-Lex tests, and dictation transcriptions conducted both at the very beginning and at the end of the semester. Findings suggest that the main difficulties and the causes of these difficulties in listening comprehension for Chinese university students at intermediate level include the following: limited knowledge of phonology, inadequate vocabulary by sound, and poor awareness of the features of connected speech. The study suggests that Chinese university students at this level need to improve their spoken word recognition and develop an awareness of the organisation of sounds in English connected speech, as these cognitive processes play a vital role in proficient listening comprehension. Similarly, it proposes that researchers and teachers working in higher education in the L2 context should work closely together to address intermediate learners’ needs and difficulties, both theoretically and practically, in order to help them enhance their listening comprehension skills

Advanced physical modeling of SiOx resistive random access memories

We apply a three-dimensional (3D) physical simulator, coupling self-consistently stochastic kinetic Monte Carlo descriptions of ion and electron transport, to investigate switching in silicon-rich silica (SiOx) redox-based resistive random-access memory (RRAM) devices. We explain the intrinsic nature of resistance switching of the SiOx layer, and demonstrate the impact of self-heating effects and the initial vacancy distributions on switching. We also highlight the necessity of using 3D physical modelling to predict correctly the switching behavior. The simulation framework is useful for exploring the little-known physics of SiOx RRAMs and RRAM devices in general. This proves useful in achieving efficient device and circuit designs, in terms of performance, variability and reliability

High-fat feeding reprograms maternal energy metabolism and induces long-term postpartum obesity in mice.

BackgroundExcessive gestational weight gain (EGWG) closely associates with postpartum obesity. However, the causal role of EGWG in postpartum obesity has not been experimentally verified. The objective of this study was to determine whether and how EGWG causes long-term postpartum obesity.MethodsC57BL/6 mice were fed with high-fat diet during gestation (HFFDG) or control chow, then their body composition and energy metabolism were monitored after delivery.ResultsWe found that HFFDG significantly increased gestational weight gain. After delivery, adiposity of HFFDG-treated mice (Preg-HF) quickly recovered to the levels of controls. However, 3 months after parturition, Preg-HF mice started to gain significantly more body fat even with regular chow. The increase of body fat of Preg-HF mice was progressive with aging and by 9 months after delivery had increased 2-fold above the levels of controls. The expansion of white adipose tissue (WAT) of Preg-HF mice was manifested by hyperplasia in visceral fat and hypertrophy in subcutaneous fat. Preg-HF mice developed low energy expenditure and UCP1 expression in interscapular brown adipose tissue (iBAT) in later life. Although blood estrogen concentrations were similar between Preg-HF and control mice, a significant decrease in estrogen receptor α (ERα) expression and hypermethylation of the ERα promoter was detected in the fat of Preg-HF mice 9 months after delivery. Interestingly, hypermethylation of ERα promoter and low ERα expression were only detected in adipocyte progenitor cells in both iBAT and WAT of Preg-HF mice at the end of gestation.ConclusionsThese results demonstrate that HFFDG causes long-term postpartum obesity independent of early postpartum fat retention. This study also suggests that HFFDG adversely programs long-term postpartum energy metabolism by epigenetically reducing estrogen signaling in both BAT and WAT

POLYETHERSULFONE COMPOSITE MEMBRANE BLENDED WITH CELLULOSE FIBRILS

Polyethersulfone (PES) is a common material used for ultrafiltration (UF) membranes, which has good chemical resistance, high mechanical properties, and wide temperature tolerances. The hydrophobic property of the PES membrane seriously limits its application. Cellulose fibrils are composed of micro-sized and nano-sized elements, which have high hydrophilicity, strength, and biodegradation. A composite membrane was prepared by the phase inversion induced by an immersion process. The characteristics of the composite membrane were investigated with Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and atomic force microscopy (AFM). The pure water flux of the composite membrane increased dramatically with the increase of cellulose firbils. Mean pore size and porosity were significantly increased. Both mechanical properties and hydrophilicity were enhanced due to the addition of the cellulose firbils