Two CEGAR-based approaches for the safety verification of PLC-controlled plants

In this paper we address the safety analysis of chemical plants controlled by programmable logic controllers (PLCs). We consider a specification of the control program of the PLCs, extended with the specification of the dynamic plant behavior. The resulting hybrid models can be transformed to hybrid automata, for which advanced techniques for reachability analysis exist. However, the hybrid automata models are often too large to be analyzed. We propose two counterexample-guided abstraction refinement (CEGAR) approaches to keep the size of the hybrid models moderate.     

Transforming Perceived Vocal Effort and Breathiness Using Adaptive Pre-Emphasis Linear Prediction

This paper presents a technique to transform high-effort voices into breathy voices using adaptive pre-emphasis linear prediction (APLP). The primary benefit of this technique is that it estimates a spectral emphasis filter that can be used to manipulate the perceived vocal effort. The other benefit of APLP is that it estimates a formant filter that is more consistent across varying voice qualities. This paper describes how constant pre-emphasis linear prediction (LP) estimates a voice source with a constant spectral envelope even though the spectral envelope of the true voice source varies over time. A listening experiment demonstrates how differences in vocal effort and breathiness are audible in the formant filter estimated by constant pre-emphasis LP. APLP is presented as a technique to estimate a spectral emphasis filter that captures the combined influence of the glottal source and the vocal tract upon the spectral envelope of the voice. A final listening experiment demonstrates how APLP can be used to effectively transform high-effort voices into breathy voices. The techniques presented here are relevant to researchers in voice conversion, voice quality, singing, and emotion.     

Requirements for a virtual environment to support the social participation education of low-literates

People of low literacy experience difficulties while participating in society. Learning support software could help alleviate these difficulties. However, there is currently no overview of theoretically and empirically sound requirements for this kind of support. This paper uses the situated cognitive engineering method to create a requirements baseline for a virtual environment to support the societal participation education of low-literates (VESSEL), based on an analysis of the domain, human factors, and current applications. Four major outcomes are presented. First, a comprehensive overview is collected of the operational demands and human factors knowledge relevant to societal participation learning for low-literate citizens. Second, this overview is translated into a list of eight functional requirements: focused on low-literate learners, set in the context of societal participation, and supported by claims of cognitive, affective, and social benefits to learning. Third, a sample of Dutch societal participation learning support programs is assessed using these requirements, to highlight both current technology best practices and discrepancies between theory and practice. Fourth, virtual learning environment technology is suggested as an ‘enabling’ technology; an overview is shown of how virtual environments, actors, and objects can beneficially enable meeting the requirements baseline. Finally, directions for future study are discussed.

     

Index of Keywords to Volume 27

Other Index

Index of Keywords to Volume 27     

Upper Limb Robot Mediated Stroke Therapy—GENTLE/s Approach

Stroke is a leading cause of disability in particular affecting older people. Although the causes of stroke are well known and it is possible to reduce these risks, there is still a need to improve rehabilitation techniques. Early studies in the literature suggest that early intensive therapies can enhance a patient's recovery. According to physiotherapy literature, attention and motivation are key factors for motor relearning following stroke. Machine mediated therapy offers the potential to improve the outcome of stroke patients engaged on rehabilitation for upper limb motor impairment. Haptic interfaces are a particular group of robots that are attractive due to their ability to safely interact with humans. They can enhance traditional therapy tools, provide therapy on demand and can present accurate objective measurements of a patient's progression. Our recent studies suggest the use of tele-presence and VR-based systems can potentially motivate patients to exercise for longer periods of time. The creation of human-like trajectories is essential for retraining upper limb movements of people that have lost manipulation functions following stroke. By coupling models for human arm movement with haptic interfaces and VR technology it is possible to create a new class of robot mediated neuro rehabilitation tools. This paper provides an overview on different approaches to robot mediated therapy and describes a system based on haptics and virtual reality visualisation techniques, where particular emphasis is given to different control strategies for interaction derived from minimum jerk theory and the aid of virtual and mixed reality based exercises.     

帕克厌氧技术处理化工废水

近20年来．化工行业环保意识的增强使得人们在环保方面的投资逐渐增加。其中一个重要的内部原因是在化工行业内部执行了ISO14001等环境管理系统。正如废水成分与上游生产相关．废水成分也成为一种管理信息．它可以有助于提高化工工艺的生产效率(减少产品损失、水耗和能耗)。另一个重要的外部原因是地方法规和环保税收体系(排放标准)的建立和实施。以上这2方面原因导致了人们对化工行业环境污染控制系统的逐渐关注。     

Anaerobic treatment of pulp and paper mill effluents--status quo and new developments.

Since the early 1980s, anaerobic treatment of industrial effluents has found widespread application in the pulp and paper industry. Over 200 installations are treating a large variety of different pulp and paper mill effluents. Amongst various anaerobic systems the UASB and IC are the most applied anaerobic reactor systems. Anaerobic treatment is well feasible for effluents originated from recycle paper mills, mechanical pulping (peroxide bleached), semi-chemical pulping and sulphite and kraft evaporator condensates. The advantages of anaerobic pre-treatment are (1) net production of renewable energy (biogas), (2) minimized bio-solids production, (3) minimal footprint and (4) reduced emission of greenhouse gases. Via in-line application of anaerobic treatment in closed circuits (paper kidney technology) further savings on cost of fresh water intake and effluent discharge levies are generated.     

Mutation analysis of the rearranged immunoglobulin heavy chain genes of marginal zone cell lymphomas indicates an origin from different marginal zone B lymphocyte subsets

Marginal zone cell lymphoma is a recently described entity among the non-Hodgkin's lymphomas. It likely originates from the marginal zone B cells in the spleen and equivalent cells in the lymph node and extranodal tissues. Recent evidence indicates that marginal zone B cells are functionally heterogeneous and may differ with respect to the pattern of somatic hypermutation in their Ig variable genes. To test whether marginal zone lymphomas may originate from different subsets of marginal zone B cells, we performed a sequence and mutation analysis of the rearranged Ig heavy chain (IgH) variable genes (VH) of a series of 14 cases of marginal zone lymphoma, occurring in the spleen (4), the lymph node (4), the stomach (2), the orbit (2), the tongue (1), and the skin (1). Our data show that marginal zone cell lymphomas preferentially rearrange the VH4, VH3, and VH1 family genes, without preference for any particular VH gene. Somatic mutations are present in 13 cases; one case of marginal zone cell lymphoma of the skin showed a germline configuration of the rearranged VH gene. Mutation analysis shows evidence of antigen selection in three cases of marginal zone cell lymphoma, one of the spleen, stomach, and orbit, respectively. No evidence of antigen selection was present in the other cases. These data indicate that marginal zone cell lymphomas may arise from different subsets of marginal zone B cells. In addition, lymphomagenesis may not be triggered by antigen in all cases of marginal zone cell lymphoma.     

In vivo cross-linking of the SecA and SecY subunits of the Escherichia coli preprotein translocase

Precursor protein translocation across the Escherichia coli inner membrane is mediated by the translocase, which is composed of a heterotrimeric integral membrane protein complex with SecY, SecE, and SecG as subunits and peripherally bound SecA. Cross-linking experiments were conducted to study which proteins are associated with SecA in vivo. Formaldehyde treatment of intact cells results in the specific cross-linking of SecA to SecY. Concurrently with the increased membrane association of SecA, an elevated amount of cross-linked product was obtained in cells harboring overproduced SecYEG complex. Cross-linked SecA copurified with hexahistidine-tagged SecY and not with SecE. The data indicate that SecA and SecY coexist as a stable complex in the cytoplasmic membrane in vivo.