Using mathematical modelling to evaluate drivers and predict trajectories of HIV and STI epidemics in South East Asian and Australian populations

Objective To evaluate the potential impact of the current global economic crisis (GEC) on the spread of HIV. Design To evaluate the impact of the economic downturn we studied two distinct HIV epidemics in Southeast Asia: the generalized epidemic in Cambodia where incidence is declining and the epidemic in Papua New Guinea (PNG) which is in an expansion phase. Methods Major HIV-related risk factors that may change due to the GEC were identified and a dynamic mathematical transmission model was developed and used to forecast HIV prevalence, diagnoses, and incidence in Cambodia and PNG over the next 3 years. Results In Cambodia, the total numbers of HIV diagnoses are not expected to be largely affected. However, an estimated increase of up to 10% in incident cases of HIV, due to potential changes in behavior, may not be observed by the surveillance system. In PNG, HIV incidence and diagnoses could be more affected by the GEC, resulting in respective increases of up to 17% and 11% over the next 3 years. Decreases in VCT and education programs are the factors that may be of greatest concern in both settings. A reduction in the rollout of antiretroviral therapy could increase the number of AIDS-related deaths (by up to 7.5% after 3 years). Conclusions The GEC is likely to have a modest impact on HIV epidemics. However, there are plausible conditions under which the economic downturns can noticeably influence epidemic trends. This study highlights the high importance of maintaining funding for HIV programs.

Gravity-induced coronal plane joint moments in the adolescent scoliotic spine

INTRODUCTION Calculating segmental (vertebral level-by-level) torso masses in Adolescent Idiopathic Scoliosis (AIS) patients allows the gravitational loading on the scoliotic spine during relaxed standing to be estimated. METHODS Existing low dose CT scans were used to calculate vertebral level-by-level torso masses and joint moments occurring in the spine for a group of female AIS patients with right-sided thoracic curves. Image processing software, ImageJ (v1.45 NIH USA) was used to reconstruct the torso segments and subsequently measure the torso volume and mass corresponding to each vertebral level. Body segment masses for the head, neck and arms were taken from published anthropometric data. Intervertebral joint moments at each vertebral level were found by summing each of the torso segment masses above the required joint and multiplying it by the perpendicular distance to the centre of the disc. RESULTS AND DISCUSSION Twenty patients were included in this study with a mean age of 15.0±2.7 years and a mean Cobb angle 52±5.9°. The mean total trunk mass, as a percentage of total body mass, was 27.8 (SD 0.5) %. Mean segmental torso mass increased inferiorly from 0.6kg at T1 to 1.5kg at L5. The coronal plane joint moments during relaxed standing were typically 5-7Nm at the apex of the curve (Figure 1), with the highest apex joint of 7Nm. CT scans were performed in the supine position and curve magnitudes are known to be 7-10° smaller than those measured in standing [1]. Therefore joint moments produced by gravity will be greater than those calculated here. CONCLUSIONS Coronal plane joint moments as high as 7Nm can occur during relaxed standing in scoliosis patients, which may help to explain the mechanics of AIS progression. The body mass distributions calculated in this study can be used to estimate joint moments derived using other imaging modalities such as MRI and subsequently determine if a relationship exists between joint moments and progressive vertebral deformity.

Software watermarking resilient to debugging attacks

In 2006, Gaurav Gupta and Josef Pieprzyk presented an attack on the branch-based software watermarking scheme proposed by Ginger Myles and Hongxia Jin in 2005. The software watermarking model is based on replacing jump instructions or unconditional branch statements (UBS) by calls to a fingerprint branch function (FBF) that computes the correct target address of the UBS as a function of the generated fingerprint and integrity check. If the program is tampered with, the fingerprint and/or integrity checks change and the target address is not computed correctly. Gupta and Pieprzyk's attack uses debugger capabilities such as register and address lookup and breakpoints to minimize the requirement to manually inspect the software. Using these resources, the FBF and calls to the same is identified, correct displacement values are generated and calls to FBF are replaced by the original UBS transferring control of the attack to the correct target instruction. In this paper, we propose a watermarking model that provides security against such debugging attacks. Two primary measures taken are shifting the stack pointer modification operation from the FBF to the individual UBSs, and coding the stack pointer modification in the same language as that of the rest of the code rather than assembly language to avoid conspicuous contents. The manual component complexity increases from O(1) in the previous scheme to O(n) in our proposed scheme.

Mathematical modelling and experimental validation of solar assisted heat pump system

Singapore is located at the equator, with abundant supply of solar radiation, relatively high ambient temperature and relative humidity throughout the year. The meteorological conditions of Singapore are favourable for efficient operation of solar energy based systems. Solar assisted heat pump systems are built on the roof-top of National University of Singapore’s Faculty of Engineering. The objectives of this study include the design and performance evaluation of a solar assisted heat-pump system for water desalination, water heating and drying of clothes. Using MATLAB programming language, a 2-dimensional simulation model has been developed to conduct parametric studies on the system. The system shows good prospect to be implemented in both industrial and residential applications and would give new opportunities in replacing conventional energy sources with green renewable energy.

Mathematical Models of Tumor-Immune System Dynamics

"This collection of papers offers a broad synopsis of state-of-the-art mathematical methods used in modeling the interaction between tumors and the immune system. These papers were presented at the four-day workshop on Mathematical Models of Tumor-Immune System Dynamics held in Sydney, Australia from January 7th to January 10th, 2013. The workshop brought together applied mathematicians, biologists, and clinicians actively working in the field of cancer immunology to share their current research and to increase awareness of the innovative mathematical tools that are applicable to the growing field of cancer immunology. Recent progress in cancer immunology and advances in immunotherapy suggest that the immune system plays a fundamental role in host defense against tumors and could be utilized to prevent or cure cancer. Although theoretical and experimental studies of tumor-immune system dynamics have a long history, there are still many unanswered questions about the mechanisms that govern the interaction between the immune system and a growing tumor. The multidimensional nature of these complex interactions requires a cross-disciplinary approach to capture more realistic dynamics of the essential biology. The papers presented in this volume explore these issues and the results will be of interest to graduate students and researchers in a variety of fields within mathematical and biological sciences."--Publisher website

Mathematical modelling of fumigant transport in stored grain

Computational fluid dynamics, analytical solutions, and mathematical modelling approaches are used to gain insights into the distribution of fumigant gas within farm-scale, grain storage silos. Both fan-forced and tablet fumigation are considered in this work, which develops new models for use by researchers, primary producers and silo manufacturers to assist in the eradication grain storage pests.

Web mediated market interactions and enterprise software

With increased consolidation and a few large vendors dominating the market, how can software vendors distinguish themselves in order to maintain profitability and gain market share? Increasingly customers are becoming more proactive in selecting a vendor and a product, drawing upon various publications, market surveys, mailing lists, and, of course, other users. In particular, though, a company's Web site is the obvious place to begin information gathering. In sum, it may seem that the days of the uninformed customer prepared to be "sold to" are potentially all but gone.

Reflections on issues of power in packaged software selection

The adoption of packaged software is becoming increasingly common in a variety of organizations and much of the packaged software literature presents this as a straightforward, linear process based on rationalistic evaluation. This paper applies the framework of power relations developed by Markus and Bjørn-­‐Anderson (1987) to a longitudinal study concerning the adoption of a customer relationship management package in a small organization. This is used to highlight both overt and covert power issues within the selection and procurement of the product and illustrate the interplay of power between senior management, IT managers, IT vendors and consultants, and end-­‐users. The paper contributes to the growing body of literature on packaged software and also to our understanding of how power is deeply embedded within the surrounding processes.

IT consultants, salesmanship and the challenges of packaged software selection in SMEs

Purpose – This paper seeks to analyse the process of packaged software selection in a small organization, focussing particularly on the role of IT consultants as intermediaries in the process. Design/methodology/approach – This is based upon a longitudinal, qualitative field study concerning the adoption of a customer relationship management package in an SME management consultancy. Findings – The authors illustrate how the process of “salesmanship”, an activity directed by the vendor/consultant and focussed on the interests of senior management, marginalises user needs and ultimately secures the procurement of the software package. Research limitations/implications – Despite the best intentions the authors lose something of the rich detail of the lived experience of technology in presenting the case study as a linear narrative. Specifically, the authors have been unable to do justice to the complexity of the multifarious ways in which individual perceptions of the project were influenced and shaped by the opinions of others. Practical implications – Practitioners, particularly those from within SMEs, should be made aware of the ways in which external parties may have a vested interest in steering projects in a particular direction, which may not necessarily align with their own interests. Originality/value – This study highlights in detail the role of consultants and vendors in software selection processes, an area which has received minimal attention to date. Prior work in this area emphasises the necessary conditions for, and positive outcomes of, appointing external parties in an SME context, with only limited attention being paid to the potential problems such engagements may bring.

The social shaping of packaged software selection

As organisations increasingly engage in the selection, purchase, and adoption of packaged software products, how these activities are carried out in practice becomes increasingly relevant for researchers and practitioners. Our focus in this paper is to propose a framework for understanding the packaged software selection process. The functionalist literature on this area of study suggests a number of generic recommendations, which are based on rational assumptions about the process and view the decision making that takes place as producing the “best technology solution.’” To explore this, we conducted a longitudinal, in-depth study of packaged software selection in a small organisation. For interpretation of the case, we draw upon the Social Construction of Technology, a theoretical framework arguing that technology is socially constituted and regarding the process of development as contradictory and uncertain. We offer a number of contributions. First, we further our understanding of packaged software selection with the critique that we offer of the functionalist literature, drawing insights from the emerging critical/constructivist literature and expanding our domain of interest to encompass the wider environment. Second, we weave this together with our experiences in the field, drawing on social constructivism for theoretical support, to develop a framework of packaged software selection that shows how various actors shape the process.

CRM packaged software : a study of organisational experiences

Customer Relationship Management (CRM) packaged software has become a key contributor to attempts at aligning business and IT strategies in recent years. Throughout the 1990s there was, in many organisations strategies, a shift from the need to manage transactions and toward relationship management. Where Enterprise Resource Planning packages dominated the management of transactions era, CRM packages lead in regard to relationships. At present, balanced views of CRM packages are scantly presented instead relying on vendor rhetoric. This paper uses case study research to analyse some of the issues associated with CRM packages. These issues include the limitations of CRM packages, the need for a relationship orientation and the problems of a dominant management perspective of CRM. It is suggested that these issues could be more readily accommodated by organisational detachment from beliefs in IT as utopia, consideration of prior IS theory and practice and a more informed approach to CRM package selection.

Potential pitfalls in packaged software adoption

The common reasons for those in organizations adopting large config- urable packaged software products are compelling. Problems with the existing software situation, the supposed predictability and perceived business benefits of packaged software, and various social influences, can lead to packages being preferred to custom approaches. Yet, for every reason, there is a potential associated problem that must be understood before an informed adoption decision can be made...

Achieving enterprise integration through software customization : part I-evidence from the field

Achieving business and IT integration is strategic goal for many organisations – it has almost become the ‘Holy Grail’ of organisational success. In this environment Enterprise Resource Planning (ERP) packages have become the defacto option for addressing this issue. Integration has come to mean adopting ERP, through configuration and without customization, but this all or nothing approach has proved difficult for many organisations. In part 1 of a 2 part update we provide evidence from the field that suggests that whilst costly, if managed appropriately, customization can have value in aiding organisational integration efforts. In part 2, we discuss in more detail the benefits and pitfalls involved in enacting a non-standard based integration strategy.

Achieving enterprise integration through software customization : part II-enacting the strategy

In part 1 of this update, we put forward the argument that integration in ERP based environments can be achieved in ways other than adopting a software configuration only approach. We drew on evidence from two large ERP implementations to show how, despite the cost implications, some customization, if carefully managed, could prove helpful. In this, the final part of the update, we discuss the benefits, and potential pitfalls, involved in enacting a non-standard based integration strategy. This requires attention to a) broadening the integration definition; b) bringing legacy practices forward and c) developing a customization based integration strategy.

Vagueness and software engineering

We do not commonly associate software engineering with philosophical debate. Indeed, software engineers ought to be concerned with building software systems and not settling philosophical questions. I attempt to show that software engineers do, in fact, take philosophical sides when designing software applications. In particular, I look at how the problem of vagueness arises in software engineering and argue that when software engineers solve it, they commit to philosophical views that they are seldom aware of. In the second part of the paper, I suggest a way of dealing with vague predicates without having to confront the problem of vagueness itself. The purpose of my paper is to highlight the currently prevalent disconnect between philosophy and software engineering. I claim that a better knowledge of the philosophical debate is important as it can have ramifications for crucial software design decisions. Better awareness of philosophical issues not only produces better software engineers, it also produces better engineered products.