Discrete-Event Simulation versus Constrained Graphic Modelling of Construction Processes

Effective construction project planning and control requires the development of a model of the project’s construction processes.  The Critical Path Method (CPM) is the most popular project modelling method in construction since it is relatively simple to use and reasonably versatile in terms of the range of processes it can represent.  Several other modelling techniques have been developed over the years, each with their own advantages and disadvantages.  Linear scheduling, for example, has been designed to provide highly insightful visual representations of a construction process, but unfortunately is largely incapable of representing non-repetitive construction work.  Discrete-event simulation is generally agreed to be the most versatile of all modelling methods, but it lacks the simplicity in use of CPM and so has not been widely adopted in construction.  A new graphical constraint-based method of modelling construction processes, Foresight, has been developed with the goal of offering the simplicity in use of CPM, the visual insight of linear scheduling, and the versatility of simulation.  Earlier work has demonstrated the modelling versatility of Foresight.  As part of a continuing study, this paper focuses on a comparison of the Foresight approach with discrete-event construction simulation methods, specifically Stroboscope (a derivative of CYCLONE). Foresight is shown to outperform Stroboscope in terms of the simplicity of the resultant models for a series of case studies involving a number of variants of an earthmoving operation and of a sewer tunnelling operation.  A qualitative comparison of the two approaches also highlights the superior visual insight provided by Foresight over conventional simulation, an attribute essential to both the effective verification and optimization of a model

Graph theoretic methods for radio equipment selection

In the 1970s and 1980s, a small group of American engineers recognised the importance of the graph-colouring ideas studied by mathematicians and the potential for these ideas to be used in practical radio frequency assignment procedures. Some groundbreaking work led to a long period of study in academia where many variants on the Frequency Assignment Problem have been considered and some advanced algorithms developed. This thesis has investigated the Frequency Assignment Problem for microwave fixed links and, taking account of the constraints experienced in professional practice, extended this to include the problem of Equipment Selection. For a particular data-rate, standard radio equipment using relatively lower-or higher order modulation schemes can be deployed by the fixed link operator. While the higher-order options use less bandwidth, they radiate at higher powers and require more protection in the radio interference environment. That is, they are more potent interferers and present a greater challenge to distant interferers. Therefore, when the assigner’s objective is to minimise the span of frequencies used by a network, the higher-order modulation radio is not always the most spectrally efficient. The thesis has hypothesised that by doubling the bandwidth requirement on selected links, the assigner can actually reduce the overall span of frequencies used to support a frequency assignment for the entire network. With a minimum span objective, fixed link deployment scenarios have been exposed to a standard IP Solver that gives exact solutions. Using graph-theoretic methods, equipment selection heuristics have been developed and tested in offline and online environments. This work has gathered significant evidence in support of the hypothesis

Developments in Hyper Real-Time Simulation of Transient Heat-Flow in Buildings

This paper reports on the latest results in the development of a new approach for simulating the thermal behavior of buildings that overcomes the limitations of conventional heat-transfer simulation methods such as FDM and FEM. The proposed technique uses a coarse-grain approach to model development whereby each element represents a complete building component such as a wall, internal space, or floor. The thermal behavior of each coarse-grain element is captured using empirical modeling techniques such as artificial neural networks (ANNs). The main advantages of the approach compared to conventional simulation methods are: (a) simplified model construction for the end-user; (b) simplified model reconfiguration; (c) significantly faster simulation runs (orders of magnitude faster for two and three-dimensional models); and (d) potentially more accurate results. The paper demonstrates the viability of the approach through a number of experiments with a model of a composite wall. The approach is shown to be able to sustain highly accurate longterm simulation runs, if the coarse-grain modeling elements are implemented as ANNs. In contrast, an implementation of the coarse-grain elements using a linear model is shown to function inaccurately and erratically. The paper concludes with an identification of on-going work and future areas for development of the technique

Radiolarian biostratigraphy of Peninsular Malaysia and implications for regional palaeotectonics and palaeogeography

Peninsular Malaysia consists of three terranes, a western Gondwanan affinity terrane (Sibumasu), an eastern Cathaysian affinity terrane (Indochina/East Malaya) and an accretionary complex terrane (the Palaeo-Tethyan Bentong-Raub suture zone) which contains fault-bounded blocks and clasts of radiolarian-bearing chert and argillite. ... The representation of the Palaeo-Tethyan suture zone of Peninsular Malaysia as a narrow zone (13 - 18 km wide) is not favoured in this study. The Gondwanan affinity Sibumasu terrane is narrower than presently defined and includes only passive margin continental sequences. All radiolarian-bearing chert and argillite, belts of mélange and imbricate thrust slices of marine sedimentary rocks characteristic of accretionary complexes are not part of the Sibumasu or Indochina/East Malaya terranes, but are of Palaeo-Tethyan origin, and form a distinct accretionary complex terrane which has been thrust westwards over the eastwards-dipping Sibumasu terrane. The Bentong-Raub suture zone of Peninsular Malaysia, the Uttaradit-Nan/Sra Kaeo suture zone of Thailand and the Changning-Menglian suture zone of South China have yielded radiolarian faunas of similar biostratigraphic ages, ranging from Upper Devonian (Famennian), through Middle Triassic (Ladinian). These ages suggest that the Palaeo-Tethys ocean existed between the Sibumasu and Indochina terranes from at least Late Devonian through to Middle Triassic (Ladinian) time. Results of this thesis support tectonic models that propose Late Silurian - Early Devonian rifting of continental fragments from the Gondwanan margin, Devonian opening of the Palaeo-Tethys, and subsequent closure of the ocean in Peninsular Malaysia and Southeast Asia during the Late Triassic

Illawarra Born cross-generational health study: feasibility of a multi-generational birth cohort study

Background: There is a strong interest in the concept of developmental origins of health and disease and their influence on various factors from cradle to grave . Despite the increasing appreciation of this lifelong legacy across the human life course, many gaps remain in the scientific understanding of mechanisms influencing these formative phases. Cross-generational susceptibility to health problems is emerging as a focus of research in the context of birth cohort studies. The primary aim of the Illawarra Born study is to make scientific discoveries associated with improving health and wellbeing across the lifespan, with a particular focus on preventable chronic diseases, especially mental health. This birth cohort study will follow and collect data from three cohorts representing different stages across the lifespan: infants, adults (parents) and older adults (grandparents). The multi-generational, cross-sectional and longitudinal design of this birth cohort study supports a focus on the contributions of genetics, environment and lifestyle on health and wellbeing. The feasibility of conducting a multi-generational longitudinal birth cohort project was conducted through a small pilot study. Methods/design: The purpose of this paper is to report on the feasibility and acceptability of the research protocol for a collaborative cross-generation health study in the community and test recruitment and outcome measures for the main study. This feasibility study included pregnant women who were intending to give birth in the Illawarra-Shoalhaven region in Eastern Australia. The area includes a large, regional referral hospital, with capacity to treat specialist and complex cases. Pregnant women were asked to participate in five data collection waves beginning at 22 weeks gestation and ending with a 6-month post-partum appointment. Recruitment was then extended, via the pregnant women, to also include fathers and maternal grandmothers. Discussion: This feasibility study focused on the perinatal period and collected data across three multi-disciplinary domains including mental health, diet, exposures to toxins and the role of these in maternal and infant outcomes. Forty-one families participated in extensive data collection from 22 weeks gestation to 6-months post-partum. Factors impacting on viability and feasibility including recruitment solutions provide the basis for a large-scale study

Nigeria Presidential and National Assembly Elections:25 February 2023

In line with the provisions of the 2018 Revised Commonwealth Guidelines for the Conduct of Election Observation in Member Countries, the Commonwealth Secretary-General, Rt Hon Patricia Scotland KC, constituted an Observer Group for the 25 February 2023 presidential and National Assembly elections in Nigeria, following an invitation from the Chair of the Independent National Electoral Commission (INEC).The Commonwealth Observer Group was led by His Excellency Thabo Mbeki, former President of the Republic of South Africa, and comprised 16 other eminent Commonwealth citizens. A staff team of 11 from the Commonwealth Secretariat provided technical support to the Group

Polarons as Nucleation Droplets in Non-Degenerate Polymers

We present a study of the nucleation mechanism that allows the decay of the metastable phase (trans-cisoid) to the stable phase (cis-transoid) in quasi one-dimensional non-degenerate polymers within the continuum electron-phonon model. The electron-phonon configurations that lead to the decay, i.e. the critical droplets (or transition state), are identified as polarons of the metastable phase. We obtain an estimate for the decay rate via thermal activation within a range of parameters consistent with experimental values for the gap of the cis-configuration. It is pointed out that, upon doping, the activation barriers of the excited states are quite smaller and the decay rate is greatly enhanced. Typical activation energies for electron or hole polarons are $\approx 0.1$ eV and the typical size for a critical droplet (polaron) is about $20 \AA$. Decay via quantum nucleation is also studied and it is found that the crossover temperature between quantum nucleation and thermal activation is of order $T_c \leq 40 ^oK$. Metastable configurations of non-degenerate polymers may provide examples for mesoscopic quantum tunneling.Comment: REVTEX 3.0, 28 PAGES, 3 FIGURES AVAILABLE UPON REQUEST, PITT 94-0

ERS/EAACI statement on adherence to international adult asthma guidelines

Clinical practice guidelines based on the best available evidence, aim to standardize and optimize asthma diagnosis and management. Nevertheless, there are concerns that particularly between different groups of healthcare professionals (HCPs), adherence to guidelines is suboptimal. Further to these concerns, the aims of this ERS/EAACI Statement were (1) via an international online survey, to evaluate and compare the understanding of and adherence to international asthma guidelines by HCPs of different specialties, (2) via systematic reviews of the literature, to assess effectiveness of strategies focused at improving implementation of guideline-recommended interventions, and compare process and clinical outcomes in patients managed by Specialists (respiratory physicians or allergists) or Generalists (internists or general practitioners). The online survey identified discrepancies between HCPs of different specialties which may be due to poor dissemination or lack of knowledge of the guidelines but also a reflection of the adaptations HCPs working in different clinical settings make, based on their resources. The systematic reviews demonstrated that multifaceted quality improvement initiatives addressing multiple challenges to guidelines adherence, or the input from additional specialized HCPs are most effective in improving guidelines adherence. More data are needed to evaluate differences in process and clinical outcomes among patients managed by Generalists or Specialists. Our results reveal a need for guidelines to consider the heterogeneity of real-life settings for asthma management and tailor their recommendations accordingly. Continuous, multifaceted quality improvement processes are required to optimize and maintain guidelines adherence. Validated referral pathways for uncontrolled asthma or for uncertain diagnosis are needed