A model for smoothing time‐series data in construction

The understanding of the behaviour of time‐series data has been a matter of concern to researchers and practitioners in a variety of fields ranging from social science and economics to engineering. Also, the behaviour of many phenomena within fields relating and peripheral to construction is described as a time series. Typically, the time‐series analysis is carried out in order to forecast the future values of the series. These techniques, however, are also used to abstract the generalities within the series, hence facilitating the replication of the entire profile, reflecting only the main characteristics of the profile. There is a variety of techniques that can be applied to a set of time‐related data. The choice of the technique is, therefore, dependent on the nature of the problem and the characteristics of the data. The diversity of available techniques is, on the one hand an advantage for all analysts. However, this diversity is also an indication that there is no universal technique that is applicable to a diversity of time‐series data.

This work fundamentally addresses the issue of smoothing and curve‐fitting techniques rather than predicting and forecasting. A technique is offered which is tested against a set of criteria that are designed to focus on the accuracy of imitation and the practicality of operation: the ability to deal with a large number of time‐series sets of data in a consistent, replicable and automated way. The viability of the technique is demonstrated by its application to expenditure profiles of a large number of construction projects. The size of the sample and the diversity in the profiles of the expenditure patterns provided an appropriate testing ground for the universality of the model.

The results indicated that the model can effectively transform a jagged time series into a smooth pattern, while complying with a set of criteria many of which are common to several other research works relating to time‐series data analysis. The proposed technique sequences a number of basic smoothing methods and the process involves the treatment and incorporation of the residual values.     

A linear‐discrete scheduling model for the resource‐constrained project scheduling problem

For some specific types of construction projects, the classical CPM or PDM scheduling techniques are not the most suitable. Few specific scheduling approaches have been developed to cope with construction projects that are made of either repetitive activities or activities with linear developments. But real‐world construction projects do not consist only of such activities. They are generally made of a mixture of linear and/or repetitive activities and of more conventional activities. To allow this, the linear scheduling problem is reformulated, so classical schedule calculation approaches can be used. The implementation of some Allen's algebra features to avoid adverse discontinuities and to allow crew/work continuity, together with a resource‐driven and space‐constrained scheduling are among the key features of the proposed approach. It is also a spin‐off of off‐the‐field practices used for scheduling real projects in the particle accelerator construction domain; an excerpt from such a construction project is provided for illustrating the methodology.     

Urban aesthetics and the discovery of the urban fabric in turn‐of‐the‐century Germany

Approaches to planning that developed in the later nineteenth century in Germany (and in Europe generally) were challenged on aesthetic grounds at the end of the century by Camillo Sitte and others. By the turn of the century, practitioners of planning had embraced Sitte's views on a number of matters. Among the changes that occurred were an end to the disencumbering of monumental buildings and a greatly expanded interest in historic preservation. This was not simply a matter of aesthetics gaining more influence over planning practice, however. Sitte's desire to develop systematically the aesthetic dimension of planning was shared by earlier theorists, notably Hermann Maertens, who endorsed many of the practices Sitte rejected. Ultimately, the compatibility of the new aesthetics with more practical needs was crucial to its acceptance. The new interest in historical models reflected an understanding of urban form that enabled planners to reconcile their aesthetic goals with other needs.     

Negotiation‐based decision support model for utility relocations in transportation infrastructure projects

Highway projects in metropolitan areas often require that adjacent utilities be relocated to accommodate new or expanded highway facilities. Traditionally, utility owners have been responsible for their own relocations prior to highway construction. However, utility relocation delay was reported as one of the root causes of overall project delays in highway construction. In the USA, one strategic approach sporadically taken over the past 15 years by some state departments of transportation (DOTs) has been to combine utility relocation work with the highway contractor's scope of work. While the combined strategy offers many benefits, it does have its own set of challenges and disadvantages. Many of these difficulties involve disagreements between DOTs and utility owners over the appropriateness of the combined strategy for particular types of relocations. Hence, a negotiation‐based decision support model (DSM) for determining whether to use the combined strategy was developed to provide guidance to both DOTs and utility decision makers during the planning and design phases of highways. A literature review and interviews with experts from both DOTs and the utility industry were conducted to identify significant factors as well as their impact levels on the decision. A DSM aiming at synthesizing the factors and orchestrating the negotiation process for the decision was proposed and verified. As suggested by the model evaluators, the proposed DSM can improve the quality of this complex decision‐making process, especially for less experienced project managers or designers.     

Utility regulation in Africa: How relevant is the British model?

This article considers whether African utility regulators can draw useful lessons from the British experience over the past thirty years. We focus on three features that are considered key properties of the British regulatory model: price-cap incentive regulation, independent regulatory agencies and an emphasis on introducing competition where possible. For each property, we ask how relevant the model is for most African countries. Overall, we argue that although the British model probably has some lessons which can help improve utility performance in Africa, the problems that they help to solve are generally second-order. Ultimately, institutional weaknesses are the main root of regulatory failure in many African countries, and these weaknesses call for a model of regulation designed specifically to address them.     

Group‐level safety climate in the Australian construction industry: within‐group homogeneity and between‐group differences in road construction and maintenance

In modern organizations it is overly simplistic to assume that a uniform, organization‐wide climate for safety develops. Workgroup‐level safety climates are more likely to arise in decentralized organizations and their influence on occupational health and safety (OHS) behaviour is likely to be stronger when work is non‐routine, as in construction. The existence of workgroup‐level safety climates was examined in the Australian construction industry. A group‐level safety climate survey was conducted in a road maintenance and construction organization. The clear factorial structure produced in a larger sample of Australian defence logistics workers was not replicated and factors splintered, possibly due to the subject‐to‐item ratio in the construction study. However, the internal reliability consistency of the factors produced in the earlier pilot study was found to be acceptable for the construction industry data. Two requisite conditions for the existence of group‐level safety climates, i.e. (1) within‐group homogeneity; and (2) between‐group variation, were satisfied within the road construction and maintenance organization. The results indicate that distinct workgroup safety climates exist in construction, providing a theoretical explanation for why some workgroups perform better in OHS than others, despite having similar risk exposure.     

Just‐in‐time management in the ready mixed concrete industries of Chongqing,China and Singapore

Implementing just‐in‐time (JIT) management in the ready mixed concrete (RMC) industry seems viable. It has been observed previously by others that the current practices for managing the concrete supply chain upstream in terms of raw materials acquisition or prerequisite work on site were not geared toward JIT production. However, it is unclear if this observation is also relevant for the procurement of raw materials in the RMC industry in Chongqing (in China) and Singapore. Hence, the purpose of this study is to investigate the implementation status of JIT in the RMC industry in Chongqing and Singapore. The field study conducted found that all the RMC suppliers surveyed were using the demand pull system to manage RMC production and delivery to sites. However, the study also found that the raw materials could be purchased either using the JIT purchasing method or the traditional economic order quantity (EOQ) purchasing method. Further studies to investigate the conditions where a RMC supplier can adopt the JIT purchasing method to procure its raw materials are recommended.     

Reconstruction planning and the small town in early post‐war Britain

The development of the south bank of the central waterfront area of Rotterdam may be seen as the culmination of a process of reconstruction and redevelopment in the city that has been taking place over a considerable period, in particular since the destruction of a large part of the city's central area in the Second World War. This process has involved an evolution in the approaches to spatial planning in the city, as illustrated for instance by the development of high-profile and innovative architectural projects in recent years, as well as the development of cultural projects and the consequent adoption of a new cultural identity. Such projects have served to aid a re-definition of the city's image both within the Netherlands and at the international level. These achievements may be explained with reference to the wider urban policy context in Europe since the Second World War, the approach to urban policy in the Netherlands, and the approach to land use planning and regeneration adopted by the municipality of Rotterdam.     

Stability and interaction in the housing market: Log‐linear and vacancy chain models

Although one may find some examples of vacancy chain analysis in which the chain is actually traced, most researchers use Markov vacancy chain models now, because these are less demanding in their data requirements. In constructing this kind of model a number of assumptions have to be made, viz. regarding homogeneity, stationarity and markovicity. Before applying these models the validity of these assumptions will have to be clarified. In this contribution we will present an empirical test for some of these assumptions, using a log‐linear approach. We will also use the log‐linear model to measure the interaction among various housing submarkets. It will be shown that three types of interaction can be distinguished and measured—segmentation, dominance and substitution. Although these aspects are crucial to the study of vacancy chains, they cannot be derived directly from the results of the vacancy chain models.     

The work‐life experiences of office and site‐based employees in the Australian construction industry

A survey was conducted among employees of a large Australian construction firm. Comparisons were made between employees who differed by gender and work location. Male employees in site‐based roles reported significantly higher levels of work to family conflict and emotional exhaustion than male employees who worked in the regional or head office. Site‐based male employees were also less satisfied with their pay than male respondents who worked in the regional of head office. Few significant differences were found between women who worked in different locations. Neither were significant differences between men and women who worked in the same location reported. The results are explained in terms of women's tendency to work in administrative, secretarial or support services roles, which typically demand fewer hours. The paper concludes that the experiences of site‐based construction employees, particularly men, warrant further attention to explore the sources of work‐life imbalance and burnout.     

Landscape and the philosophy of aesthetics: is landscape quality inherent in the landscape or in the eye of the beholder?

The paper proposes that landscape quality assessment may be approached on the basis of two contrasting paradigms, one which regards quality as inherent in the physical landscape, and the other which regards quality as a product of the mind – eye of the beholder. These are termed, respectively, the objectivist and subjectivist paradigms. These paradigms underlie the surveys of the physical landscape and studies of observer preferences.Examination of these paradigms through the approaches taken by philosophers from Plato to modern times demonstrates the ubiquity of the paradigms in underlying human perception of landscape. Until recent centuries, the objectivist paradigm provided philosophers with the basis for understanding beauty, including landscape beauty. However, the philosophers Locke, Hume, Burke and particularly Immanuel Kant identified beauty as lying in the eyes of the beholder rather than in the object. The parallels between Kant's aesthetic philosophy and contemporary theories of landscape quality based on an evolutionary perspective are examined. Most philosophers over recent centuries have adopted the subjectivist view of aesthetics.The paper concludes by proposing that only the subjectivist model should be used in research of landscape quality.     

Catchment areas of medical practices and the role played by geographical distance in the patient’s choice of doctor

For a needs-planning system to be able to guarantee to provide the population with universal, locally available ambulatory medical care, it requires information concerning how patients choose their doctors, the size of the catchment areas of medical practices and the resulting distance-sensitivity of the population in relation to each medical speciality. In this contribution a model of opportunity’s preference for the health sector is developed. The key parameter of the distance sensitivity of the patients on the basis of real data is calibrated. Furthermore, this contribution empirically examines whether people in their choice of the established surgeons minimize the ways time (expense minimization) or if they are not aware of the nearest doctor, but the doctor of their confidence (act of preferential expression).     

Factors affecting the relationship between contractors and their sub‐contractors in Saudi Arabia

Delay in contract progress payment, lack of construction quality, errors and delay in shop drawings and/or approval of sample materials were ranked highest as interface problems, whilst legal disputes, scheduling conflicts amongst sub‐contractors, geological problems and weather conditions were ranked lowest.     

How price responsive is industrial demand for natural gas in the United States?

Our panel data analysis of the price responsiveness of industrial demand for natural gas in the United States utilizes five parametric specifications and 10,944 monthly observations for the lower 48 states in 2001–2019 to document statistically significant (p-value ≤ 0.05) static own-price elasticity estimates of −0.027 to −0.062, short-run −0.029 to −0.125, and long-run −0.060 to −0.179. These estimates with relatively small absolute values support the continuation of energy efficiency standards and demand-side-management programs for deep decarbonization. Further, diverse price responsiveness among heterogeneous industrial customers suggests using demand-response programs to efficiently allocate the limited supply available during a natural gas shortage.     

What is the worth of values in guiding residential preferences and choices?

The demographic, socio-economic and socio-cultural shifts that have taken place in Western economies in recent decades have generated a broader variety in housing behavior. For this reason, some researchers argue that socio-demographic characteristics alone no longer suffice to predict the housing demand. They should be supplemented with ??lifestyle?? variables. However, the worth of lifestyle for the prediction of the housing demand is a highly debated topic. The purpose of the current study, therefore, is to explore the worth of lifestyle (operationalized as values) in the prediction of residential preferences and choices. Data were collected through telephone interviews in January and February 2010. Respondents were asked to indicate the importance of 29 values as a guiding principle in housing. Furthermore, respondents who had indicated that they were willing to move (n?=?930) were asked about their preferences for a number of dwelling characteristics, such as tenure and dwelling type. Respondents who had indicated that they were not willing to move (n?=?667) provided their residential choices. Hierarchical logistic regression analyses were used to explore the relationship between values and residential preferences and choices, after correction for socio-demographic characteristics. The results showed that values might have some additional worth for predicting residential preferences and choices, but the relationship seems to be rather limited.     

Movers and Stayers on the housing market in the post‐parental stage: The Swedish case

The 1987 reform of the system of Acts on physical planning in Sweden is often referred to as a decentralization from central to local government. A review of the historical changes in Acts on Planning and Building in Sweden illustrates, however, a more complicated picture of central‐local government relations. This review, which focuses upon the constitutional‐legal dimension of this relationship, indicates shifts that have most often put central government in a more powerful position vis‐á‐vis local government. In addition, the last legal reform eliminates local government's rights to put a veto on the localization of certain industrial plants, which might cause legitimation conflicts.     

Analysis of the causality links between the growth of the construction industry and the growth of the macro‐economy in Ghana

A vibrant construction industry in a developing country, that mobilizes human and local material resources in the development and maintenance of buildings, housing and physical infrastructure, is an important means to promote increased local employment and accelerate economic growth. Ghana, a country of about 22 million people, currently has one of the fastest growing economies in West Africa. The Government of Ghana (GOG) has recently set a target of annual economic growth rate of 8% and above, up from annual growth rates of 5–6% in the past five years (2001–05). It intends to use the agricultural sector as the major vehicle for achieving such high growth rates in order for the country to reach the status of a middle income country by 2015. Surprisingly, the construction industry was left out from the list of major growth drivers of the economy. We contend that with the construction industry currently making up the third largest sector of the economy, special attention should be given to this industry as one of the main drivers of economic growth in Ghana. Therefore we conducted a study to analyse the causality links between the growth in the construction industry and the growth in the macro‐economy of Ghana, measured by the gross domestic product (GDP), to ascertain whether the construction industry can be used to lead the entire economy on a growth path. The analysis was based on a simple Granger causality test using time series data from 1968 to 2004. We showed that growth in the construction industry Granger‐caused growth in GDP, with a three‐year lag. The construction industry needs to be considered as one of the major drivers of economic growth in Ghana.     

Review and Exploration of the Development of Planning for the Conservation of the Famous Historical and Cultural Cities in China

To comprehend the development of the famous histori-cal and cultural cities in China and their conservation plan-ning, it is necessary to understand, first of all, the back-ground of their history and present condition. This back-ground has taken shape in the historic development of thecities and is influenced by many complicated factors of thepresent time. To discuss these factors in simple way, theycan be summarized as follows:The impact of the historical and cultural ideas;The impact of the physical and environmental condi-tion;The impact of the present socialand economicsituation.The impact of the historical and cultural ideasChina is a country with ancient civilization. TheChinese cultural has been shaped through development, in-heritance and harmony in a history of 5000 years on the ba-sis of the ancient Huaxia Culture with the Yellow River andthe Yangtse River as the main arteries.The rising of ancient cities in China can be traced backto over 3500 years ago. China is a multinational country. Int