Perceptual and physiological heat strain: Examination in firefighters in laboratory- and field-based studies

Firefighting demands performing heavy muscular work under adverse and potentially dangerous conditions. Although the physiological and psychological responses to simulated firefighting activities have been described, the heat strain has not been characterised using standardised indices of exercise–heat strain. The purpose of the study is to describe the physiological and perceptual strain associated with working in personal protective equipment and performing simulated firefighting activities in a hot environment using recently developed strain indices (Physiological Strain Index (PhSI); Perceptual Strain Index (PeSI)). Data from two previously published studies (Smith et al. 1995 Smith, D. L. 1995. Selected physiological and psychological responses to physical activity in different configurations of firefighting gear. Ergonomics, 38: 2065–2077. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar], 2001 Smith, D. L. 2001. Effect of strenuous live-fire fire fighting drills on hematological, blood chemistry and psychological measures. Journal of Thermal Biology, 26: 375–379. [Crossref], [Web of Science ®] , [Google Scholar]) – one a laboratory-based study and one a field-based study – were re-analysed incorporating the strain indices. The laboratory study involved walking on a treadmill for 15 min while wearing three different clothing and equipment configurations. The field study involved three trials of standardised firefighting tasks in a live-fire training structure (mean trial length = 5.76 min). Heart rate, rectal temperature, thermal sensations and ratings of perceived exertion were collected in each study. PhSI and PeSI values were calculated using the formulae developed by Moran et al. (1998b Moran, D. S., Shitzer, A. and Pandolf, K. B. 1998b. A physiological strain index to evaluate heat stress. American Journal of Physiology, 275: R129–R134. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) and Tikuisis et al. (2002 Tikuisis, P., McLellan, T. M. and Selkirk, G. 2002. Perceptual versus physiological heat strain during exercise-heat stress. Medicine & Science in Sports & Exercise, 34: 1454–1461. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]), respectively. PhSI and PeSI increased significantly over time in both studies. Even relatively brief bouts of exercise while wearing heavy impermeable clothing or simulated firefighting activity in the heat results in moderate to high levels of heat strain as assessed by PhSI and PeSI.     

Majorizing sequences for Newton's method under centred conditions for the derivative

We present semi-local and local convergence results for Newton's method in order to approximate a locally unique solution of a nonlinear equation in a Banach space setting. Our technique is more flexible than in earlier studies such that [J.A. Ezquerro, D. González, and M.A. Hernández, Majorizing sequences for Newton's method from initial value problems, J. Comput. Appl. Math. 236 (2012), pp. 2246–2258; J.A. Ezquerro, D. González, and M.A. Hernández, A general semi-local convergence result for Newton's method under centred conditions for the second derivative, ESAIM: Math. Model. Numer. Anal. 47 (2013), pp. 149–167]. The operator involved is twice Fréchet-differentiable. We also assume certain centred Lipschitz-type conditions for the derivative which are more precise than the Lipschitz conditions used in earlier works. Numerical examples are used to show that our results apply to solve equations but earlier ones do not in the semi-local case. In the local case we obtain a larger convergence ball. These advantages are obtained under the same computational cost as before [17 J.A. Ezquerro, D. González, and M.A. Hernández, Majorizing sequences for Newton's method from initial value problems, J. Comput. Appl. Math. 236 (2012), pp. 2246–2258. doi: 10.1016/j.cam.2011.11.012[Crossref], [Web of Science ®] , [Google Scholar],18 J.A. Ezquerro, D. González, and M.A. Hernández, A general semilocal convergence result for Newton's method under centered conditions for the second derivative, ESAIM: Math. Model. Numer. Anal. 47 (2013), pp. 149–167. doi: 10.1051/m2an/2012026[Crossref], [Web of Science ®] , [Google Scholar]].     

Fuzzy graphs and networks repairs

In Ref. [3] McAllister L. N. (1992) A simulation technique under uncertainty Proceedings of the 1992 NAFIPS Conference Puerto Vallarta Mexico pp. 555–563  [Google Scholar], this author provided a new definition of fuzzy graph that differs from the original definition.

In this paper, the author shows how the new definition provides with efficient numerical techniques to repair a failed link or a failed node of a network.     

A FORMALISM FOR A CASE STUDY IN THE WATERTIME PROJECT: THE CITY WATER SYSTEM IN GRENOBLE,FROM PRIVATIZATION TO REMUNICIPALIZATION

The formal representation for legal or other narratives as introduced by Nissan (2001 Nissan, E. 2001. A formalism for competing claims of identification: The “Smemorato di Collegno” amnesia case. Informatics and Computing, 20(6): 625–656. [Web of Science ®] , [Google Scholar]; ; 2003a Nissan, E. 2003a. Identification and doing without it, I: A situational classification of misapplied personal identity, with a formalism for a case of multiple usurped identity in Marivaux. Cybernetics and Systems, 34(4–5): 317–358. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]; 2003b Nissan, E. 2003b. Identification and doing without it, II: Visual evidence for pinpointing identity. How Alexander was found out: Purposeful action, enlisting support, assumed identity, and recognition. A goal-driven formal analysis. Cybernetics and Systems, 34(4–5): 359–380. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]; 2003d Nissan, E. 2003c. Identification and doing without it, III: Authoritative opinions, purposeful action, relabelled goods, and forensic examinations. The case of the stuffed birds: Its narrative dynamics set in formulae. Cybernetics and Systems, 34(6–7): 467–500. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]; 2003a Nissan, E. 2003a. Identification and doing without it, I: A situational classification of misapplied personal identity, with a formalism for a case of multiple usurped identity in Marivaux. Cybernetics and Systems, 34(4–5): 317–358. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar] is adapted to the analysis of a case study in WaterTime, a project developed by David Hall and his collaborators in view of the development of a decision model for policy making, concerning the privatization of city water systems throughout the European Union. In WaterTime, the experience of several cities is analyzed and compared. In particular, have analyzed the privatization, in 1989, of the city water system in Grenoble, France. Eventually, corruption was proven, and the system was partly remunicipalized; court decisions led to its full remunicipalization. We sketch a symbolic representation of events in this narrative.     

DYNAMIC FUZZY OWA MODEL FOR EVALUATING THE RISKS OF SOFTWARE DEVELOPMENT

How to get the relative weights in multiple criteria decision making (MCDM) problems is an important issue. In 1988, Yager proposed an ordered weighted averaging (OWA) aggregation method to find the related weights of many criteria. However, the previous aggregation operators (including OWA) and the aggregation situation are independent. For solving the problem, we propose a new aggregation situation and operator model—a dynamic fuzzy OWA model based on the evaluating situation. The OWA can modify associated weights dynamically based on the aggregation situation and work like a “magnifying lens” to enlarge and find the most important attribute dependent on the minimal information, or get equal attributes' weights based on maximal information. We also evaluate the risks of software development and compare the results with Chen's (2001 Chen , S. M. 2001 . Fuzzy group decision making for evaluating the rate of aggregative risk in software development . Fuzzy Sets and Systems , 118 : 75 – 88 .[Crossref], [Web of Science ®] , [Google Scholar]) and Lee's (1996 Lee , H. M. 1996 . Group decision making using fuzzy sets theory for evaluating the rate of aggregative risk in software development . Fuzzy Sets and Systems , 80 : 261 – 271 .[Crossref], [Web of Science ®] , [Google Scholar]) methods.     

A Novel High Quality High Capacity Image Hiding Scheme Based on Image Compression and an Optical Pixel Adjustment Process

ABSTRACT

Image hiding methods embed a secret image into a host image. The resultant stego-image does not attract the interceptors that would not detect the differences between the host image and the stego-image. To exploit the great developments in the area of image compression and to improve the quality of stego-image, this paper proposes a new method to embed the secret image into the host image. Basically, the secret image is compressed and then embedded into host image. The embedding method is based on the Optimal Pixel Adjustment Process (OPAP) and genetic algorithm. In the paper we addressed the important issues to build such systems. The experimental results showed that the proposed method can improve the quality from 60% to 80% when compared with the simple Least Significant Bit (LSB) replacement methods. Adding to that, the mean square error of the stego-image is much lower compared with other methods (Chan & Cheng, 2004 Chan, C.K. and Cheng, L.M. 2004. Hiding data in images by simple LSB substitution. Pattern Recognition, 37(3): 469–474. [Crossref], [Web of Science ®] , [Google Scholar]; Chang, Hsiao, & Chan, 2003 Chang, C.C., Hsiao, J.Y. and Chan, C.S. 2003. Finding optimal least-significant-bit substitution in image hiding by dynamic programming strategy. Pattern Recognition, 36(7): 1583–1595. [Crossref], [Web of Science ®] , [Google Scholar]; Thien & Lin, 2003 Thien, C.C. and Lin, J.C. 2003. A simple and high-hiding capacity method for hiding digit-by-digit data in images based on modulus function. Pattern Recognition, 36(12): 2875–2881. [Crossref], [Web of Science ®] , [Google Scholar]; Tseng, Chan, Ho, & Chu, 208; Wang, Lin, & Lin, 2001 Wang, R.Z., Lin, C.F. and Lin, J.C. 2001. Image hiding by optimal LSB substitution and genetic algorithm. Pattern Recognition, 34(3): 671–683. [Crossref], [Web of Science ®] , [Google Scholar]). Also, the proposed technique improves capacity. In other words, we can embed a secret image with size 450?×?450 inside a hosting image with size 512?×?512.     

MBNS Steganogram Detection and Payload Capacity Estimation Exploiting the Statistical Moments of Entropy Measure

ABSTRACT

Multiple Base Notational System (MBNS) steganography (Zhang & Wang, 2005 Zhang, X. and Wang, S. 2005. Steganography using multiple-base notational system and human vision sensitivity. IEEE Signal Processing Letters, 12(1): 67–70. [Crossref], [Web of Science ®] , [Google Scholar]) scheme employs human vision sensitivity to hide a large amount of secret bits into a still image with a high imperceptibility and is demonstrated to be robust to statistical analysis. In MBNS steganography, secret data are converted into symbols in a notational system with multiple bases. The pixels of a host image are then altered such that their remainders are equal to the symbols, when the pixel values are divided by the bases. Empirically it is observed that the moments of the entropy measure of the remainders in a stego image are larger than that of its clean counterpart. Based on this observation, we propose an active steganalytic approach which effectively breaks the MBNS steganography even with 5% payload capacity, utilizing these moments as features and also makes an estimation of the embedding rate. Experimental results demonstrate that the proposed scheme significantly outperforms prior arts in classification accuracy.     

Extending Query-Subquery Nets for Deductive Databases under the Well-Founded Semantics

ABSTRACT

We propose a method, called QSQN-WF, for evaluating queries to Datalog^¬ databases under the well-founded semantics. It is the first one that is set-at-a-time and strictly goal-directed w.r.t. SLS-resolution defined by Przymusinski. These properties are important for reducing accesses to the secondary storage and redundant computations. The first property distinguishes our method from the one based on SLG-resolution by Chen, Swift, and Warren (1995 Chen, W., T. Swift, and D. S. Warren. 1995. Efficient top-down computation of queries under the well-founded semantics. Journal of Logic Programming 24 (3):161–99. doi:10.1016/0743-1066(94)00028-5[Crossref] , [Google Scholar]) (which is tuple-at-a-time). The second property distinguishes our method from the ones based on the magic-sets transformation by Kemp, Srivastava, and Stuckey (1995 Kemp, D. B., D. Srivastava, and P. J. Stuckey. 1995. Bottom-up evaluation and query optimization of well-founded models. Theoretical Computer Science 146 (1 & 2):145–84. doi:10.1016/0304-3975(94)00153-a[Crossref], [Web of Science ®] , [Google Scholar]) and Morishita (1996 Morishita, S. 1996. An extension of Van Gelder's alternating fixpoint to magic programs. Journal of Computer and System Sciences 52 (3):506–21. doi:10.1006/jcss.1996.0038[Crossref], [Web of Science ®] , [Google Scholar]), which use magic atoms not in the most appropriate way and are not strictly goal-directed w.r.t. SLS-resolution. Our method follows SLS-resolution, with Van Gelder’s alternating fixpoint semantics on the background, but uses a query-subquery net to implement tabulation and the set-at-a-time technique, reduce redundant computations, and allow any control strategy within each iteration of the main loop. It is sound and complete w.r.t. the well-founded semantics and has PTIME data complexity.     

MODELLING OF STATISTICAL LAWS FOR TEXTS USING A PEARSON SYSTEM

In this article, we have obtained a generalization of statistical laws for texts for application to natural languages, in order to determine whether this general law is applicable to model texts in accordance with the definition given in Villacampa et al. (1999a Villacampa , Y. Castro , M. A. , Usó , J. L. , and Sastre , P. 1999a. A text theory of ecological systems. Cybernetics and Systems . 30(7): 587–807.[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]). The studies were carried out in the context of a system whose components generated model texts, through which we confirmed that the laws of Zipf and Mandelbrot are appropriate for explaining the texts. On the basis of a Pearson System, we also obtained a unique function for the distribution of frequencies, with said distribution being a generalization of the above-mentioned laws.

For the problem analyzed in this article, the text or text system constitutes a model of the cognitive development of individuals. We can thus infer the cognitive characteristics of different individuals by studying text systems.     

Perception and biomechanics data in a manual handling task: a comparative study

This paper explores the use of subjective perception tasks and its correlations with biomechanical data in the evaluation of manual material handling. Three main dimensions were considered for perception: physical regroups sensations issued from a specific body area; operative regroups feelings related to the execution of the task; and performance regroups feelings that involve a judgement on the execution or reflect overall sensations. The following questions were then explored. To what extent are perception data related to biomechanics data? Do both approaches lead to similar conclusions or interpretations when effect of practice, format and off-centre were tested? How can they complement one another? The task consisted of transferring 50 series of three 15 kg loads in order to verify the impact of free practice, format (box/cylinder) and load centre of gravity position. Eleven subjects rated perception on a CR-10 scale (Borg 1982 Borg, G. A.V. 1982. Psychophysical bases of perceived exertion. Medicine and Science in Sports and Exercise, 14: 377–381. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) after each series. The session was completed with an interview on perception. The net resulting moment was systematically found to be the best correlated with data perception. While all physical and performance items corresponded in various ways to biomechanics data, perceptions associated with operative dimension appeared to be less related with biomechanical data. As regards the impact of practice, format and off-centre, both approaches would lead to the same conclusions, except for the effect of the off-centre. Verbal data add rational information about how or why perception can or cannot be reflected in biomechanics data. How both approaches can be matched more closely in manual handling is discussed.     

A comparative assessment of IRS-P4 (MSMR)-derived sea surface temperature and sea surface wind speed over the north Indian Ocean

Indian Remote Sensing Satellite (IRS-P4) multi-frequency scanning microwave radiometer (MSMR) provides geophysical parameters like sea surface temperature (SST), sea surface wind speed (SSWS), integrated water vapour (IWV) and cloud liquid water (CLW). The retrieval procedure of these parameters given by Gohil et al. (2000 Gohil, B.S., Mathur, A.K. and Varma, A.K. Geophysical parameter retrieval over global oceans from IRS-P4 (MSMR). Preprints, Fifth Pacific Ocean Remote Sensing Conference. December5–82000, Goa. pp.207–211. Goa, , India: National Institute of Oceanography.  [Google Scholar], Geophysical parameter retrieval over global oceans from IRS-P4 (MSMR). In Preprints, Fifth Pacific Ocean Remote Sensing Conference, 5–8 December 2000, Goa, India (Goa: National Institute of Oceanography), pp. 207–211) was summarized by Sharma et al. (2002 Sharma, R., Babu, K.N., Mathur, A.K. and Ali, M.M. 2002. Identification of large scale atmospheric and oceanic features from IRS-P4 multifrequency scanning microwave radiometer: preliminary results. Journal of Atmospheric and Oceanic Technology, 19: 1127–1134. [Crossref], [Web of Science ®] , [Google Scholar], Identification of large scale atmospheric and oceanic features from IRS-P4 multifrequency scanning microwave radiometer: preliminary results. Journal of Atmospheric and Oceanic Technology, 19, pp. 1127–1134) and Jena (2007 Jena, B. 2007. Studies on the retrieval, validation and applications of geophysical parameters from IRS-P4 (MSMR) data, Orissa: PhD thesis, Berhampur University.  [Google Scholar], Studies on the retrieval, validation and applications of geophysical parameters from IRS-P4 (MSMR) data. PhD thesis, Berhampur University, Orissa). Demonstration of self-consistency of these parameters has primary scientific importance. This article deals with the validation of MSMR geophysical parameters such as SST and SSWS with in situ observations (buoy data) over the north Indian Ocean during 2000. Result shows that the MSMR-derived SST and SSWS can be utilized for several applications because of their reasonable accuracy and coverage even under cloudy condition.     

An Experimental Analysis of Experiential and Cognitive Variables in Web Navigation

Cognitive and experiential factors in human–computer interaction have been the focus of significant recent attention, but there is a lack of a much needed integrated approach to these issues. The current article proposes such an approach and applies this, combined with the person–task–artifact model (Finneran & Zhang, 2003 Finneran, C. and Zhang, P. 2003. A Person-Artefact-Task (PAT) model of flow antecedents in computer-mediated environments. International Journal of Human–Computer Studies, 59: 475–496. [Crossref], [Web of Science ®] , [Google Scholar]), to the modeling of web navigation. In an experiment, artifact complexity and task complexity were manipulated. The effects of the experimental manipulations and intrinsic motivation on flow experience, task performance and task outcome were tested. The main effects of the manipulations were confirmed. Further analyses demonstrated that flow was a mediator of the effect of experimental manipulations on task performance, and task performance was a mediator of the effect of flow on task outcome. Overall, the results in the domain of web navigation that are presented here demonstrate the need for taking an integrated cognitive-experiential approach in the modeling of human–computer interaction.     

Models of the effect of teleoperation transmission delay on robot movement time

Abstract

Recent research of [Scholcover and Gillan (2018 Scholcover, F., and D. J. Gillan. 2018. “Using Temporal Sensitivity to Predict Performance under Latency in Teleoperation.” Human Factors 60.1:80–91. doi:10.1177/0018720817734727.[Crossref], [Web of Science ®] , [Google Scholar])] has shown experimentally that system transmission delay has a linear effect on the time taken to perform a complex tracking task with a simple teleoperated robot. This note shows that, for the case of moving a robot through a straight path, this relationship is predicted. The result is a simple modification of Drury’s law to take into account the system delay. This work extends the model for performance under intermittent illumination of Drury to the effects of fixed delays in task performance, occurring with teleoperated robots. In all cases, there was empirical evidence for the predicted linear relationship.

Practitioner summary: When there is a delay in system response for robotic teleoperation between a control input and system output, movement time (MT) is increased and the increased times are linearly related to the system delay. This is true for zero and first-order control and for delays occurring before and after the control action.     

A Pair-Wise Analysis of the Cognitive Demand Levels of Mathematical Tasks Used During Classroom Instruction and Those Assigned for Homework

Abstract

This research compared the cognitive demand levels of mathematical tasks engaged in during classroom instruction to paired mathematical tasks assigned for homework. The research took place in an eighth-grade classroom over the course of one school year. In total, the cognitive demand levels of 66 mathematical tasks were evaluated using the IQA Academic Rigor: Mathematics Rubric for the Potential of the Task (Boston & Smith, 2009 Boston, M. D. and Smith, M. S. 2009. Transforming secondary mathematics teaching: Increasing the cognitive demands of instructional tasks used in teachers’ classrooms. Journal for Research in Mathematics Education, 40(2): 119–156. [Web of Science ®] , [Google Scholar]). Results from this research showed that approximately two thirds of the time the mathematical tasks assigned for homework differed in levels from the tasks used during classroom instruction. Implications for student learning, classroom instruction, homework, and further research are discussed.     

Capture of shrinking targets

‘Shrinking targets’ are targets whose size diminishes with time. The task studied is a modification of Fitts' (1954 Fitts, P. M. 1954. The information capacity of the human motor system in controlling the amplitude of movement. Journal of Experimental Psychology, 67(6): 381–391. [Crossref] , [Google Scholar]) paradigm, with the difference that, as soon as the movement is started, the target size reduces at a constant rate until it finally vanishes. Very little research has been reported on this problem apart from Johnson and Hart (1987 Johnson, W. W. and Hart, S. G. Step tracking shrinking targets. Proceedings of the Human Factors Society 31st annual meeting. October1987, New York City. pp.248–252. Santa Monica, CA: HFES.  [Google Scholar]) and Hancock and Caird (1993 Hancock, P. A. and Caird, J. K. 1993. Experimental evaluation of a model of mental workload. Human Factors, 35(3): 413–429. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). Two experiments are reported aimed at determining the parameters that affect the movement time and the probability of capturing a target when there are different amplitudes of movement, target widths and shrink rates. A multiplicative model is required to describe movement time data, which is dependent on Fitts' Index of Difficulty, the shrink rate and the product of these two variables. An alternative model describes the critical movement time, for a specified probability of target capture, in a modified form of Fitts' Law.

Statement of Relevance: Modifications of Fitts' Law have been developed for many different movement tasks. Shrinking targets occur in circumstances such as gunnery and in computer games, where a target is moving away from the person. An expression is developed for the critical time to capture the target in terms of a modified form of Fitts' Law.     

A new predicto-corrector method for pseudomonotone nonlinear complementarity problems

Based on the Logarithmic-Quadratic Proximal (LQP) method 2 Auslender, A., Teboulle, M. and Ben-Tiba, S. 1999. A logarithmic-quadratic proximal method for variational inequalities. Comput. Optim. Appl., 12: 31–40. [Crossref], [Web of Science ®] , [Google Scholar], we propose a new prediction-correction method for nonlinear complementarity problem (NCP). We obtain the predictor through a simplified inexact logarithmic-quadratic proximal method under a relaxed inexact criterion. The corrector is obtained by the improved extragradient method. Under certain conditions, the global convergence of the proposed method is proved. Preliminary numerical results indicate the efficiency of the proposed method.     

Chlorophyll concentration mapping with MIVIS data to assess crown discoloration in the Ticino Park oak forest

Airborne hyperspectral remote observations, characterized by high spatial and spectral resolution, allow the estimation of quantitative vegetation variables useful in forest condition assessment. In this research, total chlorophyll (a?+ b) concentration (C _ab), a biochemical variable describing crown discoloration rate, was mapped to assess oak (Quercus robur L.) condition in the Ticino Regional Park. A simulation experiment was conducted to evaluate the error in C _ab estimation due to ecological variables (i.e. canopy leaf area index and understorey characteristics) and to sun-sensor configurations when optical indices are used. Canopy reflectance was simulated by means of the PROSPECT leaf radiative transfer model (Jacquemoud and Baret 1990 Jacquemoud, S. and Baret, F. 1990. PROSPECT: a model of leaf optical-properties spectra. Remote Sensing of Environment, 34: 75–91. [Crossref], [Web of Science ®] , [Google Scholar]) coupled with the SAILH canopy radiative transfer model, a variation of the SAIL (Scattering by Arbitrarily Inclined Leaves) model modified to include the hot spot effect (Verhoef 1984 Verhoef, W. 1984. Light scattering by leaf layers with application to canopy reflectance modeling: The SAIL model. Remote Sensing of Environment, 16: 125–141. [Crossref], [Web of Science ®] , [Google Scholar], Kuusk 1991 Kuusk, A. 1991. “The hot-spot effect in plant canopy reflectance”. In Photon–Vegetation Interactions: Application in Optical Remote Sensing and Plant Ecology, Edited by: Mynemi, R. and Ross, J. 139–159. New York: Springer Verlag. [Crossref] , [Google Scholar]). The vegetation was modelled as a two layer medium with oak canopy as the top layer and the understorey as the bottom layer. Simulations were performed for varying leaf C _ab and canopy Leaf Area Index (LAI) of the top layer, θ_l (mean leaf inclination angle) and LAI of the bottom layer (LAI_u) and sun-sensor geometry. Optical indices were calculated and used in C _ab retrieval. Simulations demonstrated that errors in C _ab estimation were negligible when MTCI (MERIS Terrestrial Chlorophyll Index) was used, thus indicating that MTCI was the most reliable index in mapping C _ab in this forest environment. Empirical models based on optical indices were developed to map C _ab from Multispectral Infrared and Visible Imaging Spectrometer (MIVIS) images acquired by an airborne survey on the Park forested area. A regression analysis between C _ab concentration measured in leaves sampled in field and optical indices computed from hyperspectral MIVIS data was conducted. The MTCI index showed the highest performances and was therefore used to map C _ab concentration of the Ticino Park oak forest. The C _ab map was then used to assess crown discoloration level.     

A Unified User Management System

ABSTRACT

As open source software has gained in popularity throughout the last decades, free operating systems (OSs) such as Linux (Torvalds) and BSD derivatives (i.e., FreeBSD, 2012; NetBSD, 2012 NetBSD Foundation. (2012). The NetBSD project. Available from http://netbsd.org (http://netbsd.org)  [Google Scholar]; OpenBSD, 2012 OpenBSD. (2012). OpenBSD. OpenBSD. Available from http://netbsd.org (http://netbsd.org)  [Google Scholar]) have become more common, not only on datacenters but also on desktop and laptop computers. It is not rare to find computer labs or company offices composed of personal computers that boot more than one operating system. By being able to choose among available OSs, a company's or organization's information technology manager has the freedom to select the right OS for the company's needs, and the decision can be based on technical or financial criteria. This freedom of choice, however, comes with a cost. The administrative complexity of heterogeneous networks is much higher compared to single OS networks, and if the network is large enough so that protocols such as LDAP (Zeilenga, 2006 Zeilenga, K. 2006. Lightweight directory access protocol (LDAP): Technical specification road map et. alTech. rep., RFC 4510, June [Google Scholar]) or Kerberos (Kohl & Neuman, 1993 Kohl, J. and Neuman, C. 1993. The Kerberos network authentication service (v5) Tech. rep., RFC 1510, September[Crossref] , [Google Scholar]) need to be adopted, then the administration burden may become unbearable. Even though some tools exist that make user management of heterogeneous networks more feasible (Tournier, 2006 Tournier, J. (2006). smbldap-tools – summary [Gna!]. In Welcome to Gna! http://gna.org/projects/smbldap-tools (http://gna.org/projects/smbldap-tools)  [Google Scholar]; Chu & Symas Corp., 2005 Chu, H. and Symas Corp. (2005) http://www.openldap.org/devel/cvsweb.cgi/~checkout~/contrib/slapd-modules/smbk5pwd/README (http://www.openldap.org/devel/cvsweb.cgi/~checkout~/contrib/slapd-modules/smbk5pwd/README)  [Google Scholar]), it is not uncommon to use more than one back end for storing user credentials due to OS incompatibilities. In such configurations, the hardest problem to address is credential and account expiration synchronization among the different back ends. This paper demonstrates a platform that tries to mitigate the problem of synchronization by adding an additional, modular, easy to expand layer which is responsible for synchronizing any number of underlying back ends in a secure fashion.     

Mean-square stability and error analysis of implicit time-stepping schemes for linear parabolic SPDEs with multiplicative Wiener noise in the first derivative

In this article, we extend a Milstein finite difference scheme introduced in 8 Giles, M. B. and Reisinger, C. 2012. Stochastic finite differences and multilevel Monte Carlo for a class of SPDEs in finance. SIAM Financ. Math., 3(1): 572–592. (doi:10.1137/110841916)[Crossref] , [Google Scholar] for a certain linear stochastic partial differential equation (SPDE) to semi-implicit and fully implicit time-stepping as introduced by Szpruch 32 Szpruch, L. 2010. Numerical approximations of nonlinear stochastic systems PhD Thesis, University of Strathclyde [Google Scholar] for stochastic differential equations (SDEs). We combine standard finite difference Fourier analysis for partial differential equations with the linear stability analysis in 3 Buckwar, E. and Sickenberger, T. 2011. A comparative linear mean-square stability analysis of Maruyama- and Milstein-type methods. Math. Comput. Simulation, 81: 1110–1127. (doi:10.1016/j.matcom.2010.09.015)[Crossref], [Web of Science ®] , [Google Scholar] for SDEs to analyse the stability and accuracy. The results show that Crank–Nicolson time-stepping for the principal part of the drift with a partially implicit but negatively weighted double Itô integral gives unconditional stability over all parameter values and converges with the expected order in the mean-square sense. This opens up the possibility of local mesh refinement in the spatial domain, and we show experimentally that this can be beneficial in the presence of reduced regularity at boundaries.     

A comparison among different modified Priestley and Taylor equations to calculate actual evapotranspiration with MODIS data

Priestley and Taylor's (1972) equation to estimate evapotranspiration (ET) stands for its simple form and data requirement. Although the original equation was developed for saturated surfaces, it has been widely extended to unsaturated surfaces. In this paper, different hypotheses to modify Priestley and Taylor's equation for unsaturated surfaces are compared. In general, ET models for unsaturated surfaces assume that the process is ruled by the available radiant energy and surface moisture or the atmospheric conditions or both surface and air states. The results presented here suggest that both atmospheric and surface variables should be jointly parameterized in order to obtain estimates with errors lower than 20%, which are common in ground observations. While surface condition parameterizations alone, such as those proposed by Barton (1979 Barton, I.J. 1979. A parameterization of the evaporation from nonsaturated surfaces. Journal of Applied Meteorology, 18: 43–47. [Crossref] , [Google Scholar]) and Jiang and Islam (2001 Jiang, L. and Islam, S. 2001. Estimation of surface evaporation map over southern Great Plains using remote sensing data. Water Resources Research, 37: 329–340. [Crossref], [Web of Science ®] , [Google Scholar]), show errors slightly larger than 20%, unaided atmospheric parameterization results in errors of about 50% of the mean ET. Our recently proposed model, with atmospheric and surface parameters, keeps the simple form of Priestley and Taylor's original equation while benefiting from remotely sensed data. Estimates with our model would have errors lower than 20%.