Compare Design Alternatives Research Articles

고령자를 고려한 내비게이션의 인간공학적 설계에 관한 연구

Today, the number of elderly drivers who use navigation is increasing with the growing number of elderly drivers. The purpose of this study is to provide guidelines on the interface of car navigation for elderly users. To extract significant factors which were distinguished between young and elderly users, both young and elderly users executed the driving test by installing two car navigation alternatives. The analysis was conducted through t-test. The results show that significantly different factors were the number and the meaning of the menu items in the initial screen, the location and the meaning of the menu icons in the map screen, the ease of search of the menu and the text size in the menu screen. Improvements for the factors of the initial screen and map screen were made with reference to ergonomic guidelines, and suggested through experiments comparing design alternatives for the menu screen. Design alternatives were made through a combination of investigative variables, and the analysis was conducted through ANOVA. The results show that Alternative 7 (the location of the tab was placed at the bottom, menu representation was done with the text font size of 18pt and the location of menu navigation icons was shown at the upper left) was preferred in terms of user's preference and the execution time. So if the suggested menu for elderly users are added to the existing design, both users will satisfy their desires. The guidelines suggested in this study will help the designer of car navigation take elderly users into consideration.

On the creation of future probabilistic design weather years from UKCP09

Weather data are used extensively by building scientists and engineers to study the performance of their designs, help compare design alternatives and ensure compliance with building regulations. Given a changing climate, there is a need to provide data for future years so that practising engineers can investigate the impact of climate change on particular designs and examine any risk the commissioning client might be exposed to. In addition, such files are of use to building scientists in developing generic solutions to problems such as elevated internal temperatures and poor thermal comfort. With the publication of the UK Climate Projections (UKCP09) such data can be created for future years up to 2080 and for various probabilistic projections of climate change by the use of a weather generator. Here, we discuss a method for the creation of future probabilistic reference years for use within thermal models. In addition, a comparison is made with the current set of future weather years based on the UKCIP02 projections. When used within a dynamic thermal simulation of a building, the internal environments created by the current set of future weather files lie within the range of the internal environments created by the probabilistic reference years generated by the weather generator. Hence, the main advantages of the weather generator are seen to lie in its potentially greater spatial resolution, its ability to inform risk analysis and that such files, unlike ones based on observed data, carry no copyright. Practical applications: The methodology presented in this article will allow academics and buildings engineers to create realistic hourly future weather files using the future climate data of UKCP09 weather generator. This will allow the creation of consistent future weather years for use in areas such as building thermal simulation.

Methodology to Assess Building Designs for Protection against Internal Chemical and Biological Threats

Recent world events involving chemical and biological (CB) attacks within critical infrastructure have highlighted a potential threat to buildings and their occupants. As a result, protecting buildings from CB attacks has become an important design consideration. A methodology has been developed to provide decision makers with the ability to assess multiple building designs for protection against an internal CB release. This methodology includes modeling and simulation of CB contaminant dispersion, a quantitative means to calculate a building’s protection level, and a weighted sum, multiple objective optimization for design selection. This paper outlines the phases in the methodology, and focuses on the application of multizone modeling and optimization techniques to compare design alternatives. The assessment of design options for CB protection in a hospital emergency room is used as an illustrative example. Optimal design options are determined based on the weighted combination functions for the buildin...

Modeling demand rate and imperfect proof-test and analysis of their effect on system safety

Quantitative safety assessment of a safety system plays an important role in comparing design alternatives at design stage and deciding appropriate design options to apply for safety systems. There are a number of such indices given in the literature. Most of the safety indices consider only system parameters (hazard rate, repair rate, diagnosis, coverage, etc.) along with proof-tests (or inspection). This paper extends the underlying model to incorporate demand rate and imperfect proof-tests. It also introduces a new safety index, average probability of failure on actual demand (PFaD), and an availability index, manifested availability (mAv). This paper uses Markov regenerative process-based analysis for state probabilities. Based on state-probability values of various states of the underlying Markov chain, solutions are derived for safety index PFaD and availability mAv.

Geochemical transport modelling of drainage from experimental mine tailings cells covered by capillary barriers

The use of covers with capillary barrier effects (CCBEs) for reducing acid mine drainage (AMD) from sulphidic mine tailings is simulated using the MIN3P finite volume model for coupled groundwater flow, O2 diffusion and multi-component reactive transport. The model is applied to simulate five pilot-scale in situ test cells containing reactive tailings from the Manitou mine site, Val d’Or, Que., Canada. Four of the cells were constructed with CCBEs over the tailings, while the fifth tailings cell was left uncovered. Observed and simulated discharge from the base of each cell showed that the capillary barrier covers significantly reduced sulphide oxidation and AMD. Compared to acidic discharge from the uncovered cell, discharge from the four CCBE-covered cells had neutral pH levels and 1–7 orders of magnitude lower concentrations of SO4, Fe, Zn, Cu and Al. The simulations showed that the moisture retaining layer of the CCBEs reduced AMD by inhibiting O2 diffusion into the underlying reactive wastes. Provided the moisture-retention layer of the CCBE remains close to saturation, its thickness had a relatively minor effect. Under such near-saturated conditions, O2 availability is limited by its diffusion rate through the bulk porous medium and not by the diffusion rate through the oxidized grain shells. The model is providing important new insights for comparing design alternatives for reducing or controlling AMD.

Educational Architecture-Oriented Software Linking Conceptual Design and Solar Intensity

Fundamental architectural decisions such as a building’s form and orientation greatly influence the energy performance of a building. As these decisions are taken very early in the design process, it is important for the designer to consider such performance when comparing design alternatives. Unfortunately, this is rarely done by architects. The reason can be easily tracked to the way most architects learn about energy. Simple charts and some rules of thumb are preferred over complex calculations used by engineers and energy specialists. This paper presents an experiment conducted by the writer to tackle this problem. The writer used a purpose-made software program that is developed to help architecture students learn the impact of the conceptual design decisions on the expected energy performance of a building represented in the solar intensity on the building surfaces. The paper describes the capabilities and the structure of the software program as well as the context and the results of the experiment.

An Innovative Design Approach to Reduce Drillstring Fatigue

Summary Fatigue and corrosion fatigue account for the majority of drillstring failures. 1,2 The complexity of fatigue and the drillstring designer's inability to account for a great many factors affecting the mechanism make it impractical or impossible to accurately predict a component's fatigue life in cycles to failure. This paper describes the comparative-design approach. Two dimensionless indices, curvature index (CI) and stability index (SI), have been developed to allow drillstring designers to quantitatively compare design alternatives on the basis of normalized fatigue-crack-propagation life for the purpose of selecting the one with the best fatigue performance. The two design indices will not give meaningful values of absolute fatigue life, but they will provide a quantitative comparison of the relative fatigue lives of components operating under different sets of circumstances—unknown factors being equal. This new approach normalizes many factors affecting fatigue that are generally unknown to the designer, enabling the drilling engineer to quantitatively compare the fatigue performance of available alternatives on the basis of what the drilling engineer does know. The method has already proven effective in field use.

Life cycle impact assessment of the average passenger vehicle in the Netherlands

In this article, the Life Cycle Impact Assessment of the average passenger vehicle of the Netherlands is performed, with emphasis on the current dismantling and recycling practice in this country. From calculations on recovery rates of the several material streams from ELY (End-of-Live Vehicle) recycling, it seems that attaining the European ELV legislation recycling targets (Directive 2000/53/EC 2000) is very difficult, even for countries with advanced collection and recycling infrastructures such as the Netherlands. An LCA of the current average passenger vehicle of the Netherlands, including a detailed modelling of the recovery and recycling should form a sound basis for comparison with alternative automotive life cycle designs and legislation efforts. An average passenger vehicle is defined, having average weight and material composition. A cradle to grave approach is taken, including all relevant upstream processes for the production of materials and fuels, and the return of the recycled materials to the material cycles in the EOL (End-of-Life) phase. A particularity of this model is the detailed description of the Dutch collection and recycling infrastructure, with current data for the shredding, separation and metallurgical recycling processes (ARN 2000, Barkhof 1998, Chapman 1983, Puchert et al.1994, Worrel et al. 1992). According to the Eco-indicator 99 (EI99) (Ministerie van V.R.O.M 1999), the largest environmental impact of the passenger vehicle’s life cycle occurs in the use phase — over 90% —, due to the combustion and depletion of fossil fuels. This is in agreement of previous studies (Kasai 2000, Kanesaki 2000). Also in the other life cycle phases, the use of fossil fuels is the dominant impact, even for the production phase. Resource depletion due to the use of the materials employed in the vehicle causes a comparatively lower environmental impact, namely due to the high recovery rate and efficiency of the metallurgical recycling, that balances for about 30% the total impacts of the materials production and use. NOx emission was one of the smallest emissions to air in quantity, but was responsible for 36% of the impact of the life cycle, while CO2 was the largest emission to air but caused only 6% of the environmental impact. Although there is a growing awareness and concern on increasing the recyclability of vehicles, the use phase still has the largest environmental impact of the vehicle’s life cycle. A life cycle assessment can be a sound basis to evaluate and compare design alternatives to increase the sustainability of passenger vehicles. The ASR (Automotive shredder residue) is currently the greatest concern with regard to the recovery targets. It is a large amount of materials (about 32 wt.%), difficult and costly to recycle, and thermal recovery is limited to a maximum of 15wt.% in 1015 by the European ELV legislation. Joint efforts from the automotive industry and legislative institutions are required to find a sensible solution. LCA can be a useful tool to support legislative decisions, as purely weight-based recovery definitions are not adequate to evaluate the sustainability of the automobile life cycle.

Enterprise network planning and design: methodology and application

The paper describes a business-driven enterprise network planning and design methodology that has an iterative structure to periodically assess, update, and extend the network architecture to support new business applications and requirements, account for changes in business direction, and analyze the implications of technology advances on business processes and functions. The paper focuses on the network infrastructure design and analysis task of the proposed methodology and discusses the network design and analysis of a multi-protocol application environment characterized by a client/server architecture, integration of legacy and distributed database structures, frame relay wide area network, and token ring local area networks. Detailed workload characterization and performance modeling of the application environment is presented, and network design issues are addressed. The model is used to study network performance under various load conditions, identify bottlenecks and compare design alternatives.

Fault Tree Analysis of Bridge Failure due to Scour and Channel Instability

Fault tree analysis is a systematic method of analyzing events that lead to an undesirable event. Fault trees can be used to assess the probability of failure of a system (or top event), to compare design alternatives, to identify critical events that will significantly contribute to the occurrence of the top event, and to determine the sensitivity of the probability of failure of the top event to various contributions of basic events. In this paper, fault tree analysis is used to determine the probability of failure of a bridge caused by scour and other geomorphic channel instabilities. This analysis permits an examination of a very complex system of interactions and processes that are not well understood. Minimal knowledge regarding the actual processes of scour and channel instability is required for a fault tree analysis. Three examples of analyses for actual bridges are provided showing different combinations of scour (local and contraction) and geomorphic instabilities (channel widening and degradation) at both the abutments and piers. Riprap placed at the abutments for protection is also included in the analyses.

Valuation of Experimental Management Options for Ecological Systems

Experimental tests of management policy options are becoming popular to resolve uncertainties arising from ecological processes and interactions that cannot be investigated except at field management scales. Such experiments are generally quite costly, time consuming, and sometimes risky. We need objective measures of these costs and risks to justify sensible experiments and to compare design alternatives that differ widely in cost and effectiveness. One possible measure of design performance is the expected net present value from the system, averaged over alternative hypotheses about response to experimental treatment. This present value can be estimated by dividing the future stream of expected net benefits into 2 components: short run values obtained during the experiment, and long run values obtained afterward. Experiments that are costly in the short run can be highly worthwhile for the long term if they substantially reduce the odds of using incorrect policies or of overlooking opportunities for increasing value through innovative policy choices, and if the results can be applied to many locations. Optimum experiments in terms of the expected value performance measure are not likely to have as much statistical power as scientists usually demand for traditional hypothesis testing, except in situations where the costs of incorrectly adopting a new management option are high relative to benefits obtained under that option.

96/02107 Life cycle assessment: data quality and databases practitioner survey

The application of building information modelling (BIM) in life cycle assessment (LCA) brings significant benefits, resulting in increasing publications in the field of BIM-LCA integration. However, there is no systematic examination on the present status in BIM-LCA integration. In this regard, ISO 14040 standard series provides a systematic framework. This study investigates the latest research development in BIM-LCA integration using ISO 14040 framework. The analysis focused on research studies on data collection, data mapping and data exchange between BIM and LCA data and expression of buildings’ environmental impacts from 2012 to 2021. 61 articles have been collected and analysed by using content analysis methods. The results indicate that LCA data sources are well presented in BIM-LCA integration studies but the accessibility of data from BIM model is poor. Moreover, manual work is the most popular method for data exchange. Environmental impacts from buildings are mainly presented in traditional ways such as bar charts and pie charts. This study also reveals that majority of BIM-LCA integration studies focus on comparing design alternatives. Findings of this research study identified several unaddressed issues, such as lack of understanding in applicability of each BIM-LCA integration approach and unified structure between BIM and LCA data. By drawing on these findings, authors provide recommendations on improving BIM-LCA integration, such as recommending to create strategies for selecting suitable integration approaches for different LCA scenarios. This research provides academics and practitioners with a comprehensive understanding in the current development of BIM-LCA integration, and heuristic implications for future studies.

Simulation-Based Methodology for Evaluation of High-Occupancy-Vehicle Facilities

There has been an increasing interest in improving the use of transportation facilities as environmental and social concerns have grown and as financial resources for infrastructure expansion have become increasingly scarce. Numerous programs for increasing carpooling, vanpooling, and transit usage have been undertaken to decrease reliance on single-occupant vehicles and increase the use of multioccupant vehicles. One program has been to develop facilities that give preferential treatment to high-occupancy vehicles (HOVs). Although HOV facilities have been implemented, they often have been found to be unsuccessful in attaining their stated or implied goals. Because interest in the use of HOV facilities is growing, there is a need to improve the ability to evaluate and compare design alternatives in the context of realistic (stochastic) environments. Simulation modeling has long been recognized as a powerful tool for such purposes. A structured simulation-based methodology for the evaluation of HOV design alternatives is presented. An example case study for a corridor in the Phoenix, Arizona, metropolitan area is used to demonstrate the methodology.

Simulation-Based Methodology for Evaluation of High-Occupancy-Vehicle Facilities

There has been an increasing interest in improving the use of transportation facilities as environmental and social concerns have grown and as financial resources for infrastructure expansion have become increasingly scarce. Numerous programs for increasing carpooling, van-pooling, and transit usage have been undertaken to decrease reliance on single-occupant vehicles and increase the use of multioccupant vehicles. One program has been to develop facilities that give preferential treatment to high-occupancy vehicles (HOVs). Although HOV facilities have been implemented, they often have been found to be unsuccessful in attaining their stated or implied goals. Because interest in the use of HOV facilities is growing, there is a need to improve the ability to evaluate and compare design alternatives in the context of realistic (stochastic) environments. Simulation modeling has long been recognized as a powerful tool for such purposes. A structured simulation-based methodology for the evaluation of HOV design alternatives is presented. An example case study for a corridor in the Phoenix, Arizona, metropolitan area is used to demonstrate the methodology.

Measure of manufacturing performance in advanced manufacturing systems

Because of the financial risks as a result of the high investments, decisions concerning investing in advanced manufacturing systems are difficult. The difficulty to decide is gained by the lack of a well-defined measure to support decisions and alarming messages from the industry concerning inverse phenomena upon efforts to improve the productivity. Although economical measures are used to evaluate production systems, it is argued that these measures result in wrong conclusions. Being an economic measure, the productivity is not an adequate measure to determine the manufacturing performance. As is described, the competitive performance should be the measure to support management decisions. Such a measure depends upon a lot of specialized performance measures, like economic performance, technical performance, etc. In practice, the technical measures described in the literature are inadequate to determine the technical performance. Therefore, a measure for the technical performance is introduced which is clear, timely and relevant for the shop floor and the operating departments, and which can be used to compare design alternatives of production systems and to control the production process. The economic measure (productivity) and the technical measure (transformation factor) have been used to design a new bottling line in practice. The development of the designs shows that not one measure should be considered but a combination of measures, resulting in the competitive performance.

Disassembly-Oriented Assessment Methodology to Support Design for Recycling

This paper describes an assessment methodology to support product design for the “end-of-life” phase. It is based on the assessment of feasible options for disassembling a product and applying recycling processes to its components and subassemblies. The methodology balances the future effort to be invested in recycling processes with the future benefit regainable by reduction of dumping fees and sale of recovered materials, components and subassemblies. It identifies the optimal recycling strategy for a given product with respect to multiple economical and environmental objectives of the designer. The assessment aids the designer by allowing him to compare design alternatives and identify weak spots of the design. The methodology is illustrated by assessing alternative future scenarios for the recycling of a washing machine subassembly.

Performance and traffic analysis of a network-based distributed system

In this paper we study the performance of a distributed computing system that consists of a number of clients and a server, interconnected by a carrier-sense multiple-access with collision detection (CSMA/CD) LAN. Each client represents a single-user discless workstation, or an intelligent terminal, and generates application workload using either a conventional Unix file system or the Network File System (NFS). To characterize the application workload we perform a series of measurement experiments in a controlled environment. During each experiment the traffic on the network, and the activity on the various system resources are monitored. The measurements obtained from the experiments are used to parameterize a queueing network model of the system, which is then used to project the performance of the system under various load conditions, to identify system bottlenecks, and to compare design alternatives. The results obtained from the queueing network analysis are used to determine the maximum number of clients that can be supported by the system without violating system performance requirements.

RELIABILITY METHODS FOR SHIP STRUCTURES

ABSTRACTThe ever increasing use of high‐strength materials and advanced technologies in surface ship structural design requires a very careful and systematic analysis to insure that levels of safety are maintained. This is much more easily said than done. The application of new technologies will not allow extrapolation of existing design criteria. Due to the uncertainties involved with future loading conditions, material properties, quality of workmanship in construction, and the limitations in numerical methods of analysis, the absolute safety of a structure cannot be established. It would therefore seem appropriate to use methods of analysis which would attempt to account for the various uncertainties and which allow the designer to limit the risk of unacceptable consequences. Estimation of this risk, even if used only to compare design alternatives, can be a useful and economical tool.Structural reliability has its roots in the fields of civil and aerospace engineering and has made great strides forward in the last decade. Many methods have been proposed to evaluate the risk of structural failure. These methods include: first order second moment (FOSM), advanced second moment (ASM), and Monte Carlo simulation using both conditional expectation and antithetic variates techniques for variance reduction. All of these methods consider the type of the problem, the various parameters involved, and the uncertainties associated with these parameters. In estimating the risk, the uncertainties are modeled as random variables with mean values, variance, and probability density and distribution functions. Each method uses this information in a different manner, involving some assumptions and limitations.In this paper we evaluate the available methods as to their suitability for estimating the risk of structural failure in ships. The merits and shortcomings of each method are discussed and each is then used to solve a simple example problem. The most effective method is chosen for more advanced work in this field.

Predicting the Structural Performance of Transmission Lines Uprated by Reconductoring

Uprating of transmission lines by reconductoring can be facilitated with the use of a relatively simple technique for comparing design alternatives, including existing ones, on the basis of weather records for the area of consideration. The method is illustrated for a typical 230-kV transmission line in Southern Ontario and a convenient computer program (SPUR) is described. In addition to design optimization, the new method can serve as an aid to economic decision making (cost/risk optimization) by analyzing structural performance on a statistical basis.

Risk-Based Evaluation of Design Criteria

The development of risk-based structural design criteria is described. The analysis of design uncertainties arising from the statistical nature of some variables and incomplete information regarding others is examined. The risk of unfavorable performance commensurate with the level of uncertainty is shown to provide a consistent measure of design safety and thus furnish a systematic means for comparing design alternatives. Current design provisions for reinforced concrete beams are appraised in terms of their underlying uncertainties and risks. It is shown that practical risk-based design criteria can be prescribed without unreasonable increase in design code complexity.