Optimal infinite scheduling for multi-priced timed automata

This paper is concerned with the derivation of infinite schedules for timed automata that are in some sense optimal. To cover a wide class of optimality criteria we start out by introducing an extension of the (priced) timed automata model that includes both costs and rewards as separate modelling features. A precise definition is then given of what constitutes optimal infinite behaviours for this class of models. We subsequently show that the derivation of optimal non-terminating schedules for such double-priced timed automata is computable. This is done by a reduction of the problem to the determination of optimal mean-cycles in finite graphs with weighted edges. This reduction is obtained by introducing the so-called corner-point abstraction, a powerful abstraction technique of which we show that it preserves optimal schedules. This work has been mostly done while visiting CISS at Aalborg University in Denmark and has been supported by CISS and by ACI Cortos, a program of the French Ministry of Research.     

The mitigation hierarchy upside down – a study of nature protection measures in Danish infrastructure projects

This paper presents a Danish study of mitigation directed at nature protection in environmental impact assessment (EIA) of infrastructure projects. The study is based on a document analysis of EIA reports, a workshop held with EIA professionals, and a study of two cases. The paper takes a point of departure in the mitigation hierarchy as a central conceptual framework, identifies which mitigation measures have been suggested in the EIA reports, and compares this to the mitigation hierarchy. Further, the paper explores the dynamics behind which mitigation measures are chosen and later implemented. The findings point to a discrepancy between the prevention principle embedded in the mitigation hierarchy and the actual EIA practice with increased use of nature compensation. Further, the research reveals significant variation in the design of mitigation measures, e.g. in the level of detail used in describing them and the level of clarity as to aims and actions.     

Optimal setpoint chasing in dynamic positioning of deep‐water drilling and intervention vessels

Conventional controller designs for dynamic positioning of ships and floating marine structures have so far been based on the principle on automatic positioning in the horizontal‐plane about desired position and heading co‐ordinates defined by the operator. A three degrees‐of‐freedom multivariable controller either of linear or nonlinear type, normally with feedback signals from surge, sway and yaw position and velocities, has been regarded as adequate for the control objective. For floating structures with small waterplane area such as semi‐submersibles, feedback from roll and pitch angular rotation velocity may also be included to avoid thrust‐induced roll and pitch motions that are caused by the hydrodynamic and the geometrical couplings between the horizontal and vertical planes. However, for certain marine operations this control philosophy may not be the most appropriate approach ensuring safety and cost effectiveness. For drilling and work‐over operations the main positioning objective is to minimize the bending stresses along the riser and the riser angle magnitudes at the well head on the subsea structure, and at the top joint as well. A positioning control strategy solely based on manual setting of the desired position co‐ordinates may not be the most optimal solution for these applications. In this paper a new hybrid dynamic positioning controller, that also accounts for riser angle offsets and bending stresses is proposed. It is shown that a significant reduction in riser angle magnitude can be achieved. Simulations with a drilling semi‐submersible demonstrate the effect of the proposed control strategy. Copyright © 2001 John Wiley & Sons, Ltd.     

Polarized light imaging of white matter architecture

Polarized light imaging (PLI) is a method to image fiber orientation in gross histological brain sections based on the birefringent properties of the myelin sheaths. The method uses the transmission of polarized light to quantitatively estimate the fiber orientation and inclination angles at every point of the imaged section. Multiple sections can be assembled into a 3D volume, from which the 3D extent of fiber tracts can be extracted. This article describes the physical principles of PLI and describes two major applications of the method: the imaging of white matter orientation of the rat brain and the generation of fiber orientation maps of the human brain in white and gray matter. The strengths and weaknesses of the method are set out.     

Role of midwives

Dr. Alfano (New England Journal of Medicine 296: 1126, 1977) is certainly entitled to his personal opinions, but when they appear in a major publication in a setting that calls for factual information, they cannot go unchallenged. Midwives have played and continue to play a major part in maternal-infant services in many advanced European countries. Combined midwife-physician services in Sweden, Finland, Japan, Netherlands, Denmark, Norway, and Switzerland produced infant mortality rates in 1972 superior to those reported by Dr. Alfano for the Commonwealth of Massachusetts in 1974. Even in 1967 Sweden and the Netherlands (where most infants are delivered by midwives) had infant mortality rates, respectively, of 12.9 and 13.4/100 live births. These numbers, of course, do not mean that midwives are superior to doctors, but they do not seem to prove them inferior when they are employed in an appropriate setting. In Oregon (where certified nurse-midwives have been employed for some years) the professional midwife is found mainly in the "expensive" practices, so that if there is a "3rd-level of care," it is delivered to the well-to-do rather than the indigent. It is a little early to tell, but the impression around here is that although the quality of the birth experience may be changed by addition of midwives to an upper-middle-class practice, the outcome in terms of numbers of live babies is no different. This finding may not apply when 1 is dealing with the economically disadvantaged. A striking study from California demonstrated a definite improvement in fetal outcome when certified midwives were added to an established program and a tendency for the infant mortality rate to rise again when their services were discontinued for lack of funds. A similar program is under way in Oregon, but it is much too early for results to be apparent. This letter is not written in defense of midwives - it is a plea for balance and rationality. Medicine is no place for a territorial imperative. Only by calling on the expertise of all qualified members of a society can one hope to progress and to improve the human condition.     

Oxygen transmission rates of packages at ambient,chill and freezing temperatures measured by the AOIR method

The ambient oxygen ingress rate (AOIR) method is an alternative or supplementary method to Ox‐Tran for measuring the oxygen transmission rate (OTR) of packages. The method has high capacity, requires relatively inexpensive equipment and measures OTR at different temperatures and humidity conditions. The aim of this study was, on the one hand, to study the effect of temperature on the OTR for packages produced from different polymer materials and laminates, and on the other hand to evaluate the suitability of the AOIR method at freezing temperature conditions. The OTR for 10 packages with different polymer compositions was measured at 23°C, 6°C and ?25°C. The AOIR method was shown to be a reliable test method for measuring OTR of packages at all the applied test conditions, also at frozen storage temperature. The OTR for the packages decreased with lower temperatures, especially for the packages with the highest OTR values at 23°C. In order to avoid higher packaging expenses than necessary to obtain the required shelf‐life for different food products, the OTR for alternative packages should be measured at the temperature and humidity conditions of intended use. Copyright © 2004 John Wiley & Sons, Ltd.     

Hope-focused practices during early psychotherapy sessions: Part I: Implicit approaches.

Hope is recognized as one of four key factors contributing to psychotherapeutic change across a variety theoretical approaches (Hubble, Duncan, & Miller, 1999), especially early in the psychotherapeutic sequence. To date little research has looked at how hope is translated into specific practices by psychotherapists during psychotherapy sessions. This case study employed basic interpretive inquiry (Merriam, 1998) to explore the hope-focused practices of five hope-educated psychotherapists with 11 clients early in the therapy sequence. Two categories characterize the overall findings, that is, implicit and explicit hope-focused practices. This first paper in a two-part research report focuses on implicit hope-focused interventions. Implicit hope-focused interventions were those practices identified by therapists as addressing client hope without employing the word hope explicitly. Implicit hope practices addressed two key aspects of therapy, (a) attending to therapeutic relationship, and (b) fostering client perspective change. The second paper in this series examines findings regarding explicit hope-focused interventions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Further evidence for mixed emotions.

Emotion theorists have long debated whether valence, which ranges from pleasant to unpleasant states, is an irreducible aspect of the experience of emotion or whether positivity and negativity are separable in experience. If valence is irreducible, it follows that people cannot feel happy and sad at the same time. Conversely, if positivity and negativity are separable, people may be able to experience such mixed emotions. The authors tested several alternative interpretations for prior evidence that happiness and sadness can co-occur in bittersweet situations (i.e., those containing both pleasant and unpleasant aspects). One possibility is that subjects who reported mixed emotions merely vacillated between happiness and sadness. The authors tested this hypothesis in Studies 1–3 by asking subjects to complete online continuous measures of happiness and sadness. Subjects reported more simultaneously mixed emotions during a bittersweet film clip than during a control clip. Another possibility is that subjects in earlier studies reported mixed emotions only because they were explicitly asked whether they felt happy and sad. The authors tested this hypothesis in Studies 4–6 with open-ended measures of emotion. Subjects were more likely to report mixed emotions after the bittersweet clip than the control clip. Both patterns occurred even when subjects were told that they were not expected to report mixed emotions (Studies 2 and 5) and among subjects who did not previously believe that people could simultaneously feel happy and sad (Studies 3 and 6). These results provide further evidence that positivity and negativity are separable in experience. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Lexical characteristics of words used in emotional Stroop experiments.

Validity of the emotional Stroop task hinges on equivalence between the emotion and the control words in terms of lexical features related to word recognition. The authors evaluated the lexical features of 1,033 words used in 32 published emotional Stroop studies. Emotion words were significantly lower in frequency of use, longer in length, and had smaller orthographic neighborhoods than words used as controls. These lexical features contribute to slower word recognition and hence are likely to contribute to delayed latencies in color naming. The often-replicated slowdown in color naming of emotion words may be due, in part, to lexical differences between the emotion and control words used in the majority of such studies to date. (PsycINFO Database Record (c) 2010 APA, all rights reserved)