Information flow analysis for fail-secure devices

Information security devices must preserve security properties even in the presence of faults. This in turn requires a rigorous evaluation of the system behaviours resulting from component failures, especially how such failures affect information flow. We introduce a compositional method of static analysis for fail-secure behaviour. Our method uses reachability matrices to identify potentially undesirable information flows based on the fault modes of the system's components.

Aggressive behaviour in the high-secure forensic setting: the perceptions of patients

Twenty-seven patients undergoing treatment in a high-secure forensic facility participated in focus group interviews to elicit their perceptions of (1) the factors leading to aggressive behaviour; and (2) strategies to reduce the risk of such behaviour. The focus group interviews were audiotaped, transcribed and analysed using content analysis. The participants identified that a combination of patient, staff and environmental factors contributed to violence in the study wards. The cause of aggressive behaviour centred around five major themes: the environment; empty days; staff interactions; medication issues; and patient-centred factors. Potential strategies identified by patients to reduce aggressive behaviour included: early intervention; the provision of meaningful activities to reduce boredom; separation of acutely disturbed patients; improved staff attitudes; implementation of effective justice procedures; and a patient advocate to mediate during times of conflict. Findings suggested that social and organizational factors need to be addressed to change the punitive subculture inherent in forensic psychiatric facilities, and to ensure a balance between security and effective therapy.

Using multivariate analysis to predict the behaviour of soils under effluent irrigation

Onsite wastewater treatment systems aim to assimilate domestic effluent into the environment. Unfortunately failure of such systems is common and inadequate effluent treatment can have serious environmental implications. The capacity of a particular soil to treat wastewater will change over time. The physical properties influence the rate of effluent movement through the soil and its chemical properties dictate the ability to renovate effluent. A research project was undertaken to determine the role that physical and chemical soil properties play in predicting the long-term behaviour of soil under effluent irrigation and to determine if they have a potential function as early indicators of adverse effects of effluent irrigation on treatment sustainability. Principal Component Analysis (PCA) and Cluster Analysis grouped the soils independently of their soil classifications and allowed us to distinguish the most suitable soils for sustainable long term effluent irrigation and determine the most influential soil parameters to characterise them. Multivariate analysis allowed a clear distinction between soils based on the cation exchange capacities. This in turn correlated well with the soil mineralogy. Mixed mineralogy soils in particular sodium or magnesium dominant soils are the most susceptible to dispersion under effluent irrigation. The soil Exchangeable Sodium Percentage (ESP) was identified as a crucial parameter and was highly correlated with percentage clay, electrical conductivity, exchangeable sodium, exchangeable magnesium and low Ca:Mg ratios (less than 0.5).

RSA-Grid: A grid computing based framework for power system reliability and security analysis

Grid computing is an emerging technology for providing the high performance computing capability and collaboration mechanism for solving the collaborated and complex problems while using the existing resources. In this paper, a grid computing based framework is proposed for the probabilistic based power system reliability and security analysis. The suggested name of this computing grid is Reliability and Security Grid (RSA-Grid). Then the architecture of this grid is presented. A prototype system has been built for further development of grid-based services for power systems reliability and security assessment based on probabilistic techniques, which require high performance computing and large amount of memory. Preliminary results based on prototype of this grid show that RSA-Grid can provide the comprehensive assessment results for real power systems efficiently and economically.

Training Bayesian networks for image segmentation

We are concerned with the problem of image segmentation in which each pixel is assigned to one of a predefined finite number of classes. In Bayesian image analysis, this requires fusing together local predictions for the class labels with a prior model of segmentations. Markov Random Fields (MRFs) have been used to incorporate some of this prior knowledge, but this not entirely satisfactory as inference in MRFs is NP-hard. The multiscale quadtree model of Bouman and Shapiro (1994) is an attractive alternative, as this is a tree-structured belief network in which inference can be carried out in linear time (Pearl 1988). It is an hierarchical model where the bottom-level nodes are pixels, and higher levels correspond to downsampled versions of the image. The conditional-probability tables (CPTs) in the belief network encode the knowledge of how the levels interact. In this paper we discuss two methods of learning the CPTs given training data, using (a) maximum likelihood and the EM algorithm and (b) emphconditional maximum likelihood (CML). Segmentations obtained using networks trained by CML show a statistically-significant improvement in performance on synthetic images. We also demonstrate the methods on a real-world outdoor-scene segmentation task.

Sales manager and sales team determinants of salesperson ethical behaviour

Purpose – The purpose of this paper is to develop and test a model of the role managers and peers play in shaping salespeople's ethical behaviour. The model specifies that sales manager personal moral philosophies, whether sales managers themselves are rewarded according to the outcomes or behaviours of their salespeople, sales team job security, intra-team cooperation, and sales team tactical performance all influence sales team ethical standards. In turn, ethical standards influence the probability that sales team members will behave (un)ethically when faced with ethical dilemmas. Design/methodology/approach – The model is tested on a sample of 154 Finnish sales managers. Data were collected via mail survey. Analysis was undertaken using structural equation modelling. Findings – Ethical standards appear to be shaped by several factors; behaviour-based management controls increase ethical standards, relativist managers tend to manage less ethically-minded sales teams, job insecurity impedes the development of ethical standards, and sales teams' cooperation activity increases ethical standards. Sales teams are less likely to engage in unethical behaviour when the teams have strong ethical standards. Research limitations/implications – Cross-sectional data limits generalisability; single country data may limit the ability to generalise to different sales environments; additional measure development is needed; identification of additional antecedent factors would be beneficial. Practical implications – Sales managers should consciously develop high ethical standards in sales teams if they wish to reduce unethical behaviour. Ethical standards can be improved if sales managers change their own outward behaviour (exhibit a less relativistic ethical philosophy), foster cooperation amongst salespeople, and develop perceptions of job security. How sales managers are rewarded may shape how they approach the management of ethical behaviour in their sales teams. Originality/value – This paper appears to be the first to simultaneously examine both sales manager-specific and sales team-specific antecedents to sales team ethical standards and behaviours. As such, it provides an important base for research in this critical area.

Chronotopographical analysis of the pattern onset visual evoked magnetic response (VEMR):Implications for waveform peak identification

The topography of the visual evoked magnetic response (VEMR) to a pattern onset stimulus was studied in five normal subjects using a single channel BTi magnetometer. Topographic distributions were analysed at regular intervals following stimulus onset (chronotopograpby). Two distinct field distributions were observed with half field stimulation: (1) activity corresponding to the C11 m which remains stable for an average of 34 msec and (2) activity corresponding to the C111 m which remains stable for about 50 msec. However, the full field topography of the largest peak within the first 130 msec does not have a predictable latency or topography in different subjects. The data suggest that the appearance of this peak is dependent on the amplitude, latency and duration of the half field C11 m peaks and the efficiency of half field summation. Hence, topographic mapping is essential to correctly identify the C11 m peak in a full field response as waveform morphology, peak latency and polarity are not reliable indicators. © 1993.