Optimization of large-scale rigidified inflatable structures for housing using physical programming

This paper makes important initial steps in the application of large-scale structural optimization to Rigidified Inflatable Structures (RIS) for cost competitive residential construction, and does so within the realistic framework of multiobjective optimization using the effective physical programming approach. Over the past two decades, structural optimization has proved to be an invaluable tool in numerous arenas. Its faint beginnings in civil engineering have given way to important applications in the aerospace industry, and more recently, in the automotive industry and many other areas. Importantly, structural optimization has given way to the broader field of Multidisciplinary Design Optimization (MDO). Within this context, this paper explores the feasibility of RIS design for residential construction with respect to cost, structural integrity (e.g., buckling, deformation), and other practical issues. A cylindrical structure is considered, and is subjected to code-specified snow and wind loads. Within a multiobjective framework, a physical-programming-based optimization approach is developed to examine the behavior and feasibility of reinforced and non-reinforced polymers as primary RIS materials. Using a finite element model of approximately 72000 degrees of freedom, we illustrate how the physical programming method effectively addresses the multiobjective and multiscale nature of the problem. Initial results indicate favorable feasibility of RIS use in housing. Further studies of broader scope are suggested.     

Scheduling of linear projects with single loop structures

In the last decade, a number of linear scheduling methods based on the theories of linear and dynamic programming were developed for the scheduling of linear projects. However, these methods are only suitable for the scheduling of serial linear projects (i.e. sequential activities). In this paper, a nonserial dynamic programming formulation for the scheduling and control of linear projects that involve single loop structures is presented. The objective is to provide for the selection of crew formations, interruptions, and lags for the production activities that result in the minimum project duration. The advantage of this nonserial dynamic programming approach is its ability to handle both serial and nonserial linear projects with variable crew formations and work interruptions. In addition, the system presented produces a graphical representation of the project schedule of minimum duration and updates the original schedule based on current information supplied by the user. A numerical example is included to illustrate the input and output of the system presented.     

Hi-tech for construction projects

The Hi-Tech industries today seem to be symbolised by two major developments, the supercomputer and the robot, but as yet the construction industry has benefitted little from such developments. Construction is a Mid-tech industry in a Hi-tech world, an industry with static productivity levels for two decades now, but an industry under increasing pressure from foreign construction developments to innovate. The wide array of technologies available to the industry tends to defeat the clarity of purpose necessary for change, and so an attempt is made to focus on a few key options.     

Regional estimation of resources for housing

The paper describes a procedure to estimate the resources required for a proposed housing program, on a regional basis. It comprises six separate but interrelated parts, each of which has been embodied in an interactive microcomputer program. DWELLDEM estimates the number and size of different dwelling forms (such as houses and flats) to house a forecast population demand. ELEM quantifies the building elements comprising the dwellings, such as walls and roofs. BEEP calculates material and labour inputs per unit of building element, whilst CONSBEEP enables individual inputs to be combined. RESORMAT and RESORLAB combine data on building element quantities with inputs per unit element, to produce estimates of overall resource requirements. The individual programs enable planners, builders and manufacturers to evaluate a wide range of applications, and these are described in the text.     

Communication support for prototyping projects

Communication plays a critical role in system development projects. In the paper we present our experiences with ‘communication consultants’ and ‘project diaries’, as a means of supporting system development projects using prototyping as a development strategy. Communication consultants are project members who are particularly concerned with all aspects of communication relating to a given project. Project diaries are a means of capturing the actual course of a project, and they reflect those project activities which are supplemental to conventional product documentation.     

Risk management for software projects

There is little to instruct software project managers on how to handle risk in a way that ensures the success of contingency planning and avoids crisis. This seven-step procedure describes how to identify risk factors, calculate their probability and effect on a project, and plan for and conduct risk management     

Virtual building for construction projects

Although computer-aided design is widely used in the architecture-engineering-construction (AEC) industry, the exchange of information is still largely a manual process, where 2D paper drawings are reviewed to identify conflicts. Obviously, this process is time consuming and inefficient - not only do many conflicts go undetected but it's nearly impossible to quickly determine how design changes will affect the project's cost and schedule. Thus, an average project will lose 8 to 15 percent of labor costs due to mistakes that cause change orders, delays, and rework. Project management tools also have limitations. Since they use critical path method schedules, such tools don't show the three dimensions of space and the fourth dimension of time, making it difficult to visualize and communicate the schedule and analyze the sequence of construction. Enter 4DCAD technology, which in its simplest form links 3D models to schedules.     

Computer aids for participation in housing design

This paper describes two computer programs developed to promote design participation among future building users. The software developed allows the user to create his future housing layout by assembling symbols on a computer terminal screen and be constantly guided and apprised of the environmental, spatial, locational and legislative consequences of his design decisions.     

Traceability process for large OO projects

Object-oriented software development has become popular, but scaling it up for large projects has been a problem. With large OO projects, late integration problems are a particular concern. They can cause schedule slippage and other difficulties. I developed a process called Traceability for OO Quality Engineering, or TOOQE, to minimize such problems. TOOQE emphasizes traceability and the integration of development and testing to achieve quality and maintainability. TOOQE features an iterative design process that lets developers correct mistakes and learn more about the problem they are trying to solve as they go along. Each iteration includes requirements capture, analysis, design, coding, and testing. In other words, each is a mini-life cycle     

Risk management for laboratory automation projects

This tutorial outlines some of the common risks that may be associated throughout the development and implementation of a laboratory automation project such as a laboratory information management system (LIMS) or another automation project. It presents a scheme for undertaking risk management to help assess and mitigate the degree of risk associated with each of these factors. In the case of high-risk factors, suggestions are presented to manage or help avoid the problem.Risk management is an ongoing process. It begins at the start of a project and should be reassessed at intervals throughout the project to re-evaluate existing risks and to see if any factors have changed or new ones have emerged.     

Curating GitHub for engineered software projects

Software forges like GitHub host millions of repositories. Software engineering researchers have been able to take advantage of such a large corpora of potential study subjects with the help of tools like GHTorrent and Boa. However, the simplicity in querying comes with a caveat: there are limited means of separating the signal (e.g. repositories containing engineered software projects) from the noise (e.g. repositories containing home work assignments). The proportion of noise in a random sample of repositories could skew the study and may lead to researchers reaching unrealistic, potentially inaccurate, conclusions. We argue that it is imperative to have the ability to sieve out the noise in such large repository forges. We propose a framework, and present a reference implementation of the framework as a tool called reaper, to enable researchers to select GitHub repositories that contain evidence of an engineered software project. We identify software engineering practices (called dimensions) and propose means for validating their existence in a GitHub repository. We used reaper to measure the dimensions of 1,857,423 GitHub repositories. We then used manually classified data sets of repositories to train classifiers capable of predicting if a given GitHub repository contains an engineered software project. The performance of the classifiers was evaluated using a set of 200 repositories with known ground truth classification. We also compared the performance of the classifiers to other approaches to classification (e.g. number of GitHub Stargazers) and found our classifiers to outperform existing approaches. We found stargazers-based classifier (with 10 as the threshold for number of stargazers) to exhibit high precision (97%) but an inversely proportional recall (32%). On the other hand, our best classifier exhibited a high precision (82%) and a high recall (86%). The stargazer-based criteria offers precision but fails to recall a significant portion of the population.     

Modelling housing typologies for urban redevelopment scenario planning

Increasing levels of urbanization, combined with growing populations and a need to manage urban redevelopment more sustainably has prompted the need for new tools for urban regeneration in established urban areas. While significant activity is occurring in the areas of volumetric analysis and 3D visualization, utilising these technologies in the development of urban planning tools requires a data schema for defining precinct objects for performance assessment while simultaneously addressing the complexity and interconnected nature of issues relevant to the urban built environment. This paper presents the outcomes of the research and development of a web-based 3D precinct visualization and assessment system, Envision Scenario Planner (ESP), which uses a library of housing typologies to generate easy-to-use, bottom-up, precinct-scale reports on residential infill. The paper illustrates how, through the specification of a residential precinct object data schema and the provision of a set of housing typologies, end users can quickly, and without domain knowledge, generate visualizations and assessments for a variety of housing scenarios, which allows them to determine fit-for-purpose solutions that address a range of issues relevant to contemporary planners and policy makers.     

A software development process for small projects

The authors' software development process integrates portions of an iterative, incremental process model with a quality assurance process and a measurement process that is used for process improvement. Their process aims to produce high-quality and timely results with less overhead     

An efficient heuristic algorithm for selecting projects

Consider the problem of selecting a set of projects from a large number of available projects such that at least some specified levels of benefits of various types are realized at a minimum cost. This problem can be formulated in terms of the well-known 0–1 multi-dimensional knapsack problem, a special case of the general integer programming problems. In view of the NP-completeness of these problems, this paper proposes a polynomially bounded and efficient heuristic algorithm for its solution. The proposed algorithm proceeds as follows: an initial selection is found by prioritizing the projects according to a computed discard index. This initial selection set is then altered to reduce total costs by using project exchange operations. Computational results indicate that the proposed algorithm is quite effective in finding optimal or near optimal solutions.     

A winning strategy for managing simulation projects

In this paper a winning strategy for conducting successful simulation studies is proposed. The proposed approach emphasizes risk reduction through incremental model development and encourages user commitment through team work. A case study, based on a medium-sized manufacturing facility in Missouri, is used to illustrate its application. This successful strategy can be easily adopted on other similar simulation studies.     

Model-based testing approaches selection for software projects

Selecting software technologies for software projects represents a challenge to software engineers. It is known that software projects differ from each other by presenting different characteristics that can complicate the selection of such technologies. This is not different when considering model-based testing. There are many approaches with different characteristics described in the technical literature that can be used in software projects. However, there is no indication as to how they can fit a software project. Therefore, a strategy to select model-based testing approaches for software projects called Porantim is fully described in this paper. Porantim is based on a body of knowledge describing model-based testing approaches and their characterization attributes (identified by secondary and primary experimental studies), and a process to guide by adequacy and impact criteria regarding the use of this sort of software technology that can be used by software engineers to select model-based testing approaches for software projects.