Towards a service portfolio management framework

Services in the form of business services or IT-enabled (Web) Services have become a corporate asset of high interest in striving towards the agile organisation. However, while the design and management of a single service is widely studied and well understood, little is known about how a set of services can be managed. This gap motivated this paper, in which we explore the concept of Service Portfolio Management. In particular, we propose a Service Portfolio Management Framework that explicates service portfolio goals, tasks, governance issues, methods and enablers. The Service Portfolio Management Framework is based upon a thorough analysis and consolidation of existing, well-established portfolio management approaches. From an academic point of view, the Service Portfolio Management Framework can be positioned as an extension of portfolio management conceptualisations in the area of service management. Based on the framework, possible directions for future research are provided. From a practical point of view, the Service Portfolio Management Framework provides an organisation with a novel approach to managing its emerging service portfolios.

Comparing subjective and objective measures of health : Evidence from hypertension for the income/health gradient

Economists rely heavily on self-reported measures to examine the relationship between income and health. We directly compare survey responses of a self-reported measure of health that is commonly used in nationally representative surveys with objective measures of the same health condition. We focus on hypertension. We find no evidence of an income/health greadient using self-reported hypertension but a sizeable gradient when using objectively measured hypertension. We also find that the probability of a false negative reporting is significantly income graded. Our results suggest that using commonly available self-reported chronic health measures might underestimate true income-related inequalities in health.

Nature's experiment? Handedness and early childhood development

In recent years a large body of research has investigated the various factors affecting child development and the consequent impact of child development on future educational and labour market outcomes. In this article we contribute to this literature by investigating the effect of handedness on a child and given recent research demonstrating that child development strongly affects adult outcomes. Using a large nationally representative sample of young children we find that the probability of a child being left-handed is not significantly related to child health at birth, family composition, parental employment or household income. We also find robust evidence that left-handed (and mixed handed) children perform significantly worse in nearly all measures of development than right-handed children with the relative disadvantage being larger for boys than girls. Importantly these differentials cannot be explained by different socioeconomic characteristics of the household, parental attitudes or investments in learning resources.

Cost effectiveness of antimicrobial catheters in the intensive care unit : Addressing uncertainty in the decision

Introduction: Some types of antimicrobial-coated central venous catheters (A-CVC) have been shown to be cost-effective in preventing catheter-related bloodstream infection (CR-BSI). However, not all types have been evaluated, and there are concerns over the quality and usefulness of these earlier studies. There is uncertainty amongst clinicians over which, if any, antimicrobial-coated central venous catheters to use. We re-evaluated the cost-effectiveness of all commercially available antimicrobialcoated central venous catheters for prevention of catheter-related bloodstream infection in adult intensive care unit (ICU) patients. Methods: We used a Markov decision model to compare the cost-effectiveness of antimicrobial-coated central venous catheters relative to uncoated catheters. Four catheter types were evaluated; minocycline and rifampicin (MR)-coated catheters; silver, platinum and carbon (SPC)-impregnated catheters; and two chlorhexidine and silver sulfadiazine-coated catheters, one coated on the external surface (CH/SSD (ext)) and the other coated on both surfaces (CH/SSD (int/ext)). The incremental cost per qualityadjusted life-year gained and the expected net monetary benefits were estimated for each. Uncertainty arising from data estimates, data quality and heterogeneity was explored in sensitivity analyses. Results: The baseline analysis, with no consideration of uncertainty, indicated all four types of antimicrobial-coated central venous catheters were cost-saving relative to uncoated catheters. Minocycline and rifampicin-coated catheters prevented 15 infections per 1,000 catheters and generated the greatest health benefits, 1.6 quality-adjusted life-years, and cost-savings, AUD $130,289. After considering uncertainty in the current evidence, the minocycline and rifampicin-coated catheters returned the highest incremental monetary net benefits of $948 per catheter; but there was a 62% probability of error in this conclusion. Although the minocycline and rifampicin-coated catheters had the highest monetary net benefits across multiple scenarios, the decision was always associated with high uncertainty. Conclusions: Current evidence suggests that the cost-effectiveness of using antimicrobial-coated central venous catheters within the ICU is highly uncertain. Policies to prevent catheter-related bloodstream infection amongst ICU patients should consider the cost-effectiveness of competing interventions in the light of this uncertainty. Decision makers would do well to consider the current gaps in knowledge and the complexity of producing good quality evidence in this area.

Effect of presbyopic vision corrections on perceptions of driving difficulty

Objectives: As the population ages, more people will be wearing presbyopic vision corrections when driving. However, little is known about the impact of these vision corrections on driving performance. This study aimed to determine the subjective driving difficulties experienced when wearing a range of common presbyopic contact lens and spectacle corrections.----- Methods: A questionnaire was developed and piloted that included a series of items regarding difficulties experienced while driving under daytime and night-time conditions (rated on five-point and seven-point Likert scales). Participants included 255 presbyopic patients recruited through local optometry practices. Participants were categorized into five age-matched groups; including those wearing no vision correction for driving (n = 50), bifocal spectacles (n = 54), progressive spectacles (n = 50), monovision contact lenses (n = 53), and multifocal contact lenses (n = 48).----- Results: Overall, ratings of satisfaction during daytime driving were relatively high for all correction types. However, multifocal contact lens wearers were significantly less satisfied with aspects of their vision during night-time than daytime driving, particularly regarding disturbances from glare and haloes. Progressive spectacle lens wearers noticed more distortion of peripheral vision, whereas bifocal spectacle wearers reported more difficulties with tasks requiring changes of focus and those who wore no optical correction for driving reported problems with intermediate and near tasks. Overall, satisfaction was significantly higher for progressive spectacles than bifocal spectacles for driving.----- Conclusions: Subjective visual experiences of different presbyopic vision corrections when driving vary depending on the vision tasks and lighting level. Eye-care practitioners should be aware of the driving-related difficulties experienced with each vision correction type and the need to select corrective types that match the driving needs of their patients.

Context change archetypes : understanding the impact of context change on business processes

The emergence of Enterprise Resource Planning systems and Business Process Management have led to improvements in the design, implementation, and overall management of business processes. However, the typical focus of these initiatives has been on internal business operations, assuming a defined and stable context in which the processes are designed to operate. Yet, a lack of context-awareness for external change leads to processes and supporting information systems that are unable to react appropriately and timely enough to change. To increase the alignment of processes with environmental change, we propose a conceptual framework that facilitates the identification of context change. Based on a secondary data analysis of published case studies about process adaptation, we exemplify the framework and identify four general archetypes of context-awareness. The framework, in combination with the learning from the case analysis, provides a first understanding of what, where, how, and when processes are subjected to change.

Semantic and context-based retrieval of digital cultural objects [Published in Chinese]

Cultural objects are increasingly generated and stored in digital form, yet effective methods for their indexing and retrieval still remain an important area of research. The main problem arises from the disconnection between the content-based indexing approach used by computer scientists and the description-based approach used by information scientists. There is also a lack of representational schemes that allow the alignment of the semantics and context with keywords and low-level features that can be automatically extracted from the content of these cultural objects. This paper presents an integrated approach to address these problems, taking advantage of both computer science and information science approaches. We firstly discuss the requirements from a number of perspectives: users, content providers, content managers and technical systems. We then present an overview of our system architecture and describe various techniques which underlie the major components of the system. These include: automatic object category detection; user-driven tagging; metadata transform and augmentation, and an expression language for digital cultural objects. In addition, we discuss our experience on testing and evaluating some existing collections, analyse the difficulties encountered and propose ways to address these problems.

Vitamin D in health and disease : an insight into traditional functions and new roles for the 'sunshine vitamin'

Vitamin D is unique among the vitamins in that humans can synthesize it via the action of UV radiation upon the skin. This combined with its ability to act on specific target tissues via Vitamin D Receptor’s (VDR) make its classification as a steroid hormone more appropriate. While Vitamin D deficiency is a recognized problem in some northern latitude countries, recent studies have shown even in sunny countries such as Australia, vitamin D deficiency may be more prevalent than first thought. Vitamin D is most well known for its role in bone health, however, the discovery of VDR’s on a wide variety of tissue types has also opened up roles for vitamin D far beyond traditional bone health. These include possible associations with autoimmune diseases such as multiple sclerosis and inflammatory bowel diseases, cancer, cardiovascular diseases and muscle strength. Firstly, this paper presents an overview of the two sources of vitamin D: exposure to ultraviolet-B radiation and food sources of vitamin D, with particular focus on both Australian and international studies on dietary vitamin D intake and national fortification strategies. Secondly, the paper reviews recent epidemiological and experimental evidence linking vitamin D and its role in health and disease for the major conditions linked to suboptimal vitamin D, while identifying significant gaps in the research and possible future directions for research.

Diurnal variation of corneal shape and thickness

Purpose: To investigate associations between the diurnal variation in a range of corneal parameters, including anterior and posterior corneal topography, and regional corneal thickness. ----- Methods: Fifteen subjects had their corneas measured using a rotating Scheimpflug camera (Pentacam) every 3-7 hours over a 24-hour period. Anterior and posterior corneal axial curvature, pachymetry and anterior chamber depth were analysed. The best fitting corneal sphero-cylinder from the axial curvature, and the average corneal thickness for a series of different corneal regions were calculated. Intraocular pressure and axial length were also measured at each measurement session. Repeated measures ANOVA were used to investigate diurnal change in these parameters. Analysis of covariance was used to examine associations between the measured ocular parameters. ----- Results: Significant diurnal variation was found to occur in both the anterior and posterior corneal curvature and in the regional corneal thickness. Flattening of the anterior corneal best sphere was observed at the early morning measurement (p < 0.0001). The posterior cornea also underwent a significant steepening (p < 0.0001) and change in astigmatism 90/180° at this time. A significant swelling of the cornea (p < 0.0001) was also found to occur immediately after waking. Highly significant associations were found between the diurnal variation in corneal thickness and the changes in corneal curvature. ----- Conclusions: Significant diurnal variation occurs in the regional thickness and the shape of the anterior and posterior cornea. The largest changes in the cornea were typically evident upon waking. The observed non-uniform regional corneal thickness changes resulted in a steepening of the posterior cornea, and a flattening of the anterior cornea to occur at this time.

Corneal topography with Scheimpflug imaging and videokeratography : comparative study of normal eyes

PURPOSE: To compare the repeatability within anterior corneal topography measurements and agreement between measurements with the Pentacam HR rotating Scheimpflug camera and with a previously validated Placido disk–based videokeratoscope (Medmont E300). ------ SETTING: Contact Lens and Visual Optics Laboratory, School of Optometry, Queensland University of Technology, Brisbane, Queensland, Australia. ----- METHODS: Normal eyes in 101 young adult subjects had corneal topography measured using the Scheimpflug camera (6 repeated measurements) and videokeratoscope (4 repeated measurements). The best-fitting axial power corneal spherocylinder was calculated and converted into power vectors. Corneal higher-order aberrations (HOAs) (up to the 8th Zernike order) were calculated using the corneal elevation data from each instrument. ----- RESULTS: Both instruments showed excellent repeatability for axial power spherocylinder measurements (repeatability coefficients <0.25 diopter; intraclass correlation coefficients >0.9) and good agreement for all power vectors. Agreement between the 2 instruments was closest when the mean of multiple measurements was used in analysis. For corneal HOAs, both instruments showed reasonable repeatability for most aberration terms and good correlation and agreement for many aberrations (eg, spherical aberration, coma, higher-order root mean square). For other aberrations (eg, trefoil and tetrafoil), the 2 instruments showed relatively poor agreement. ----- CONCLUSIONS: For normal corneas, the Scheimpflug system showed excellent repeatability and reasonable agreement with a previously validated videokeratoscope for the anterior corneal axial curvature best-fitting spherocylinder and several corneal HOAs. However, for certain aberrations with higher azimuthal frequencies, the Scheimpflug system had poor agreement with the videokeratoscope; thus, caution should be used when interpreting these corneal aberrations with the Scheimpflug system.

Enhancing the standard operating range of a placido disk videokeratoscope for corneal surface estimation

Abstract—Corneal topography estimation that is based on the Placido disk principle relies on good quality of precorneal tear film and sufficiently wide eyelid (palpebral) aperture to avoid reflections from eyelashes. However, in practice, these conditions are not always fulfilled resulting in missing regions, smaller corneal coverage, and subsequently poorer estimates of corneal topography. Our aim was to enhance the standard operating range of a Placido disk videokeratoscope to obtain reliable corneal topography estimates in patients with poor tear film quality, such as encountered in those diagnosed with dry eye, and with narrower palpebral apertures as in the case of Asian subjects. This was achieved by incorporating in the instrument’s own topography estimation algorithm an image processing technique that comprises a polar-domain adaptive filter and amorphological closing operator. The experimental results from measurements of test surfaces and real corneas showed that the incorporation of the proposed technique results in better estimates of corneal topography, and, in many cases, to a significant increase in the estimated coverage area making such an enhanced videokeratoscope a better tool for clinicians.

Tear film surface quality with soft contact lenses using dynamic-area high-speed videokeratoscopy

Objectives. To evaluate the performance of the dynamic-area high-speed videokeratoscopy technique in the assessment of tear film surface quality with and without the presence of soft contact lenses on eye. Methods. Retrospective data from a tear film study using basic high-speed videokeratoscopy, captured at 25 frames per second, (Kopf et al., 2008, J Optom) were used. Eleven subjects had tear film analysis conducted in the morning, midday and evening on the first and seventh day of one week of no lens wear. Five of the eleven subjects then completed an extra week of hydrogel lens wear followed by a week of silicone hydrogel lens wear. Analysis was performed on a 6 second period of the inter-blink recording. The dynamic-area high-speed videokeratoscopy technique uses the maximum available area of Placido ring pattern reflected from the tear interface and eliminates regions of disturbance due to shadows from the eyelashes. A value of tear film surface quality was derived using image rocessing techniques, based on the quality of the reflected ring pattern orientation. Results. The group mean tear film surface quality and the standard deviations for each of the conditions (bare eye, hydrogel lens, and silicone hydrogel lens) showed a much lower coefficient of variation than previous methods (average reduction of about 92%). Bare eye measurements from the right and left eyes of eleven individuals showed high correlation values (Pearson’s correlation r = 0.73, p < 0.05). Repeated measures ANOVA across the 6 second period of measurement in the normal inter-blink period for the bare eye condition showed no statistically significant changes. However, across the 6 second inter-blink period with both contact lenses, statistically significant changes were observed (p < 0.001) for both types of contact lens material. Overall, wearing hydrogel and silicone hydrogel lenses caused the tear film surface quality to worsen compared with the bare eye condition (repeated measures ANOVA, p < 0.0001 for both hydrogel and silicone hydrogel). Conclusions. The results suggest that the dynamic-area method of high-speed videokeratoscopy was able to distinguish and quantify the subtle, but systematic worsening of tear film surface quality in the inter-blink interval in contact lens wear. It was also able to clearly show a difference between bare eye and contact lens wearing conditions.

Assessment of tear film surface quality using dynamic-area high-speed videokeratoscopy

A new method for noninvasive assessment of tear film surface quality (TFSQ) is proposed. The method is based on high-speed videokeratoscopy in which the corneal area for the analysis is dynamically estimated in a manner that removes videokeratoscopy interference from the shadows of eyelashes but not that related to the poor quality of the precorneal tear film that is of interest. The separation between the two types of seemingly similar videokeratoscopy interference is achieved by region-based classification in which the overall noise is first separated from the useful signal (unaltered videokeratoscopy pattern), followed by a dedicated interference classification algorithm that distinguishes between the two considered interferences. The proposed technique provides a much wider corneal area for the analysis of TFSQ than the previously reported techniques. A preliminary study with the proposed technique, carried out for a range of anterior eye conditions, showed an effective behavior in terms of noise to signal separation, interference classification, as well as consistent TFSQ results. Subsequently, the method proved to be able to not only discriminate between the bare eye and the lens on eye conditions but also to have the potential to discriminate between the two types of contact lenses.

Modeling corneal surfaces with rational functions for high-speed videokeratoscopy data compression

High-speed videokeratoscopy is an emerging technique that enables study of the corneal surface and tear-film dynamics. Unlike its static predecessor, this new technique results in a very large amount of digital data for which storage needs become significant. We aimed to design a compression technique that would use mathematical functions to parsimoniously fit corneal surface data with a minimum number of coefficients. Since the Zernike polynomial functions that have been traditionally used for modeling corneal surfaces may not necessarily correctly represent given corneal surface data in terms of its optical performance, we introduced the concept of Zernike polynomial-based rational functions. Modeling optimality criteria were employed in terms of both the rms surface error as well as the point spread function cross-correlation. The parameters of approximations were estimated using a nonlinear least-squares procedure based on the Levenberg-Marquardt algorithm. A large number of retrospective videokeratoscopic measurements were used to evaluate the performance of the proposed rational-function-based modeling approach. The results indicate that the rational functions almost always outperform the traditional Zernike polynomial approximations with the same number of coefficients.