Source code watermarking based on function dependency oriented sequencing

In the current market, extensive software development is taking place and the software industry is thriving. Major software giants have stated source code theft as a major threat to revenues. By inserting an identity-establishing watermark in the source code, a company can prove it's ownership over the source code. In this paper, we propose a watermarking scheme for C/C++ source codes by exploiting the language restrictions. If a function calls another function, the latter needs to be defined in the code before the former, unless one uses function pre-declarations. We embed the watermark in the code by imposing an ordering on the mutually independent functions by introducing bogus dependency. Removal of dependency by the attacker to erase the watermark requires extensive manual intervention thereby making the attack infeasible. The scheme is also secure against subtractive and additive attacks. Using our watermarking scheme, an n-bit watermark can be embedded in a program having n independent functions. The scheme is implemented on several sample codes and performance changes are analyzed.

Numerical modelling and design of lipped channel beams subject to shear

Cold-formed steel members are increasingly used as primary structural elements in buildings due to the availability of thin and high strength steels and advanced cold-forming technologies. Cold-formed lipped channel beams (LCB) are commonly used as flexural members such as floor joists and bearers. Many research studies have been carried out to evaluate the behaviour and design of LCBs subject to pure bending actions. However, limited research has been undertaken on the shear behaviour and strength of LCBs. Hence a numerical study was undertaken to investigate the shear behaviour and strength of LCBs. Finite element models of simply supported LCBs with aspect ratios of 1.0 and 1.5 were considered under a mid-span load. They were then validated by comparing their results with test results and used in a detailed parametric study based on the validated finite element models. Numerical studies were conducted to investigate the shear buckling and post-buckling behaviour of LCBs. Experimental and numerical results showed that the current design rules in cold-formed steel structures design codes are very conservative for the shear design of LCBs. Improved design equations were therefore proposed for the shear strength of LCBs. This paper presents the details of this numerical study of LCBs and the results.

Practical aspects of frequency-domain identification of dynamic models of marine structures from hydrodynamic data

The motion response of marine structures in waves can be studied using finite-dimensional linear-time-invariant approximating models. These models, obtained using system identification with data computed by hydrodynamic codes, find application in offshore training simulators, hardware-in-the-loop simulators for positioning control testing, and also in initial designs of wave-energy conversion devices. Different proposals have appeared in the literature to address the identification problem in both time and frequency domains, and recent work has highlighted the superiority of the frequency-domain methods. This paper summarises practical frequency-domain estimation algorithms that use constraints on model structure and parameters to refine the search of approximating parametric models. Practical issues associated with the identification are discussed, including the influence of radiation model accuracy in force-to-motion models, which are usually the ultimate modelling objective. The illustration examples in the paper are obtained using a freely available MATLAB toolbox developed by the authors, which implements the estimation algorithms described.

Joint identification of infinite-frequency added mass and fluid-memory models of marine structures

This paper addresses the problem of joint identification of infinite-frequency added mass and fluid memory models of marine structures from finite frequency data. This problem is relevant for cases where the code used to compute the hydrodynamic coefficients of the marine structure does not give the infinite-frequency added mass. This case is typical of codes based on 2D-potential theory since most 3D-potential-theory codes solve the boundary value associated with the infinite frequency. The method proposed in this paper presents a simpler alternative approach to other methods previously presented in the literature. The advantage of the proposed method is that the same identification procedure can be used to identify the fluid-memory models with or without having access to the infinite-frequency added mass coefficient. Therefore, it provides an extension that puts the two identification problems into the same framework. The method also exploits the constraints related to relative degree and low-frequency asymptotic values of the hydrodynamic coefficients derived from the physics of the problem, which are used as prior information to refine the obtained models.

Surface dosimetry for very small X-ray beams

Introduction The dose to skin surface is an important factor for many radiotherapy treatment techniques. It is known that TPS predicted surface doses can be significantly different from actual ICRP skin doses as defined at 70 lm. A number of methods have been implemented for the accurate determination of surface dose including use of specific dosimeters such as TLDs and radiochromic film as well as Monte Carlo calculations. Stereotactic radiosurgery involves delivering very high doses per treatment fraction using small X-ray fields. To date, there has been limited data on surface doses for these very small field sizes. The purpose of this work is to evaluate surface doses by both measurements and Monte Carlo calculations for very small field sizes. Methods All measurements were performed on a Novalis Tx linear accelerator which has a 6 MV SRS X-ray beam mode which uses a specially thin flattening filter. Beam collimation was achieved by circular cones with apertures that gave field sizes ranging from 4 to 30 mm at the isocentre. The relative surface doses were measured using Gafchromic EBT3 film which has the active layer at a depth similar to the ICRP skin dose depth. Monte Carlo calculations were performed using the BEAMnrc/EGSnrc Monte Carlo codes (V4 r225). The specifications of the linear accelerator, including the collimator, were provided by the manufacturer. Optimisation of the incident X-ray beam was achieved by an iterative adjustment of the energy, spatial distribution and radial spread of the incident electron beam striking the target. The energy cutoff parameters were PCUT = 0.01 MeV and ECUT = 0.700 - MeV. Directional bremsstrahlung splitting was switched on for all BEAMnrc calculations. Relative surface doses were determined in a layer defined in a water phantom of the same thickness and depth as compared to the active later in the film. Results Measured surface doses using the EBT3 film varied between 13 and 16 % for the different cones with an uncertainty of 3 %. Monte Carlo calculated surface doses were in agreement to better than 2 % to the measured doses for all the treatment cones. Discussion and conclusions This work has shown the consistency of surface dose measurements using EBT3 film with Monte Carlo predicted values within the uncertainty of the measurements. As such, EBT3 film is recommended for in vivo surface dose measurements.

CTCombine : rotating and combining CT data with an accurate detector model to simulate radiotherapy portal imaging at non-zero beam angles

Established Monte Carlo user codes BEAMnrc and DOSXYZnrc permit the accurate and straightforward simulation of radiotherapy experiments and treatments delivered from multiple beam angles. However, when an electronic portal imaging detector (EPID) is included in these simulations, treatment delivery from non-zero beam angles becomes problematic. This study introduces CTCombine, a purpose-built code for rotating selected CT data volumes, converting CT numbers to mass densities, combining the results with model EPIDs and writing output in a form which can easily be read and used by the dose calculation code DOSXYZnrc...

lacZ transduced human breast cancer xenografts as an in vivo model for the study of invasion and metastasis

A number of human cancer cell lines have been described as being invasive and metastatic in immune incompetent animals. However, it is difficult to assess metastatic spread of a subcutaneously injected or inoculated cell line, since an exact detection of all microfoci of human tumour cells in the animals by usual histological procedures would require extensive sectioning of the whole animal. To overcome this problem, we transduced human breast cancer cells with a replication-defective Moloney murine leukaemia retroviral vector (M-MuLV) containing both neo(R) (neomycin resistance) and lacZ genes. The resulting cell lines were selected for antibiotic (G418) resistance, and cell-sorted for lacZ expression. lacZ continued to be expressed in cultured cells for at least 20 passages without further G418 selection. The lacE gene codes for β-D-galactosidase, and cells expressing this gene stain blue with the chromogenic substrate X-gal. The lacZ-expressing cells retained the pre-transduction ability to traverse Matrigel in vitro, to form subcutaneous tumours in nude mice, and to grow invasively with the formation of metastases. X-gal staining showed high specificity, staining the tumour cells but not the surrounding mouse tissue on either whole tissue blocks or histological sections. The staining procedure was highly sensitive, allowing detection of microfoci of human cancer cells, and quantitative estimation of the metastatic capacity of the cells. These results indicate that lacZ transduction of human tumour cells is a powerful means of studying human cancer cell invasion and metastases in vivo.

10,000 steps Rockhampton : (1) building a whole community approach to increasing levels of physical activity

10,000 Steps Rockhampton is a multi-strategy health promotion program which aims to develop sustainable community-based strategies to increase physical activity.The central coordinating focus of the project is the use of pedometers to raise awareness of and provide motivation for physical activity, around the theme of '10,000 steps/day - Every step counts.' To date, five key strategies have been implemented: (1) a media-based awareness raising campaign; (2) promotion of physical activity by health professionals; (3) improving social support for physical activity through group-based programs; (4) working with local council to improve environmental support for physical activity, and; (5) establishment of a ‘micro-grants’ fund to which community groups could apply for assistance with small, innovative physical activity enhancing projects. Strategies were introduced on a rolling basis beginning in February 2002 with 'layering' of interventions designed to address the multi-level individual social and environmental determinants of physical activity. The project was quasi-experimental in design, involving collection of baseline and two year follow-up data from community based surveys in Rockhampton and in a matched regional Queensland town. In August 2001,the baseline CATI survey (N=1281)found that 47.9% of men and 33.0% of women were meeting the national guidelines for physical activity. In August 2002, a smaller survey (N=400) found an increase in activity levels among women (39.7% active) but not in men (48.5%). Data from the two year follow up survey, to be conducted in August 2003, will be presented, with discussion of the major successes and challenges of this landmark physical activity intervention. Acknowledgement: This project is supported by a grant from Health Promotion Queensland.

10,000 steps Rockhampton: a whole community approach to increasing levels of physical activity

10,000 Steps Rockhampton is a multi-strategy health promotion program which aims to develop sustainable community-based strategies to increase physical activity.The central coordinating focus of the project is the use of pedometers to raise awareness of and provide motivation for physical activity, around the theme of '10,000 steps/day - Every step counts.' To date, five key strategies have been implemented: (1) a media-based awareness raising campaign; (2) promotion of physical activity by health professionals; (3) improving social support for physical activity through group-based programs; (4) working with local council to improve environmental support for physical activity, and; (5) establishment of a ‘micro-grants’ fund to which community groups could apply for assistance with small, innovative physical activity enhancing projects. Strategies were introduced on a rolling basis beginning in February 2002 with 'layering' of interventions designed to address the multi-level individual social and environmental determinants of physical activity. The project was quasi-experimental in design, involving collection of baseline and two year follow-up data from community based surveys in Rockhampton and in a matched regional Queensland town. In August 2001,the baseline CATI survey (N=1281)found that 47.9% of men and 33.0% of women were meeting the national guidelines for physical activity. In August 2002, a smaller survey (N=400) found an increase in activity levels among women (39.7% active) but not in men (48.5%). Data from the two year follow up survey, to be conducted in August 2003, will be presented, with discussion of the major successes and challenges of this landmark physical activity intervention. Acknowledgement: This project is supported by a grant from Health Promotion Queensland

Risk mitigation of post-earthquake fire in urban buildings

Post-earthquake fire (PEF) is considered one of the most high risk and complicated problems affecting buildings in urban areas and can cause even more damage than the earthquake itself. However, most standards and codes ignore the implications of PEF and so buildings are not normally designed with PEF in mind. What is needed is for PEF factors to be routinely scrutinized and codified as part of the design process. A systematic application is presented as a means of mitigating the risk of PEF in urban buildings. This covers both existing buildings, in terms of retrofit solutions, and those yet to be designed, where a PEF factor is proposed. To ensure the mitigation strategy meets the defined criteria, a minimum time is defined – the safety guaranteed time target – where the safety of the inhabitants in a building is guaranteed.

Building community coalitions for the promotion of physical activity: 10,000 steps Rockhampton

The 10,000 Steps Rockhampton project is a multi-strategy community-wide, physical activity intervention based on the simultaneous implementation of five strategies, each identified as 'best practice' for the promotion of physical activity. Several community partners were engaged to develop and implement the strategies during the first eighteen months of the project. These included: the local media (TV, newspaper and radio); the local Division of General Practice and other health professional groups; the Heart Foundation and ‘Just Walk It’; the local council; and several large worksites. A local physical activity task force was also formed to administer a 'micro-grants' scheme, and to guide the development of community based strategies. The presentation will focus on the critical elements involved in developing and maintaining relationships with community partners. These include identification and ‘courting’ of potential partners, strategies for keeping them engaged, and the challenges of maintaining the balance between ‘top-down’ (evidence-based) and ‘bottom-up’ (community-driven) strategies. Data on implementation and uptake of the key strategies will also be presented. These include: 1) process data on the number of health