Causes,Effects,and Control Measures of Construction Change Orders in the U.S.

Change orders have a significant impact on many aspects of construction projects.They are known to be the primary cause of litigation in the construction industry.Change orders are almost inevitable due to the uniqueness of each project from many perspectives,such as the type of building,complexity of the design,human factors,and the available resources.Change orders are the formal mechanism to implement design changes during the execution phase.These changes are usually the outcome of lack of visualization by the owner,misunderstanding,miscommunication between different parties involved in the project,shortage in resources,and other factors.This research aims to investigate and rank causes,effects,and control measures of change orders in the construction industry in the U.S.This research presents the results of a questionnaire surveying owners,contractors,and consultants.A total of 123 industry professionals in the Architecture,Engineering,and Construction(AEC)field,with either significant or final decision-making authority on reviewing,issuing,and approving change orders responded to the survey.Results indicated that owners are the primary source followed by consultants and contractors,respectively.Some of the more important control measures identified in this research are collaboration and visualization technologies.

A Comparative Analysis of Visualization Methods in Architecture:Employing Virtual Reality to Support the Decision-Making Process in the Architecture,Engineering,and Construction Industry

The design process of the built environment relies on the collaborative effort of all parties involved in the project.During the design phase,owners,end users,and their representatives are expected to make the most critical design and budgetary decisions-shaping the essential traits of the project,hence emerge the need and necessity to create and integrate mechanisms to support the decision-making process.Design decisions should not be based on assumptions,past experiences,or imagination.An example of the numerous problems that are a result of uninformed design decisions is“change orders”,known as the deviation from the original scope of work,which leads to an increase of the overall cost,and changes to the construction schedule of the project.The long-term aim of this inquiry is to understand the user’s behavior,and establish evidence-based control measures,which are actions and processes that can be implemented in practice to decrease the volume and frequency of the occurrence of change orders.The current study developed a foundation for further examination by proposing potential control measures,and testing their efficiency,such as integrating Virtual Reality(VR).The specific aim was to examine the effect of different visualization methods(i.e.,VR vs.construction drawings)on,(1)how well the subjects understand the information presented about the future/planned environment;(2)the subjects’perceived confidence in what the future environment will look like;(3)the likelihood of changing the built environment;(4)design review time;and(5)accuracy in reviewing and understanding the design.

从话语的促销化看话语构建社会

社会构建主义认为,话语不只简单地反映社会,话语能够构建社会。话语是社会变化最敏感的指标。Fairclough提出,话语和社会之间有个辨证的关系。一方面,话语是由社会构建形成的,另一方面,话语也能构建社会。社会变化能改变话语的秩序,新的话语秩序帮助构建新的现实社会。本文通过对2004年的一个同学聚会上的一位同学的讲话的分析来支持Fairclough的话语和社会互为构建的观点,并证明半公共话语也有市场促销化的趋势。本文着重探讨话语能从主观上帮助人们去感知社会变化的观点。

高等教育话语的新变迁——机构身份再构建的跨学科研究

本文旨在论述话语分析可以作为语言学和社会学理论之阀的聚合点加以研究。作者将以其当前从 事的高校机构身份在新的话语实践中再构建的研究课题为例来阐述这一理论视角。

CONSTRUCTION OF HIGH ORDER SYMPLECTIC PRK METHODS

In this paper three classes of high order symplectic partitioned Runge-Kutta (PRK) methods, which are based on the W-transformation of Hairer and Wanner, and a particular class of diagonally implicit symplectic PRK methods of arbitrarily high order, which are based on the composite algorithm, are constructed. In particular, the symplectically composite PRK methods of arbitrarily high order become explicit when applied to separable Hamiltonian systems.

A Note on C-wrpp Semigroups

In this paper, we give equivalent characterizations of C wrpp semigroups.

MULTIPLICATIVE EXTRAPOLATION METHOD FOR CONSTRUCTING HIGHER ORDER SCHEMES FOR ORDINARY DIFFERENTIAL EQUATIONS

In this paper, we develop a new technique called multiplicative extrapolation method which is used to construct higher order schemes for ordinary differential equations. We call it a new method because we only see additive extrapolation method before. This new method has a great advantage over additive extrapolation method because it keeps group property. If this method is used to construct higher order schemes from lower symplectic schemes, the higher order ones are also symplectic. First we introduce the concept of adjoint methods and some of their properties. We show that there is a self-adjoint scheme corresponding to every method. With this self-adjoint scheme of lower order, we can construct higher order schemes by multiplicative extrapolation method, which can be used to construct even much higher order schemes. Obviously this constructing process can be continued to get methods of arbitrary even order.

语用身份建构研究:对比与梳理

语用身份建构研究是近年来国内语用学界的一个热点话题,在理论和应用上不断发展,取得了丰硕的成果,但还有进一步发展的空间。本文通过对比国外相关身份研究,从语用身份与社会身份的关系、语用身份选择与话语选择的关系、自我身份建构与对方身份建构的关系、语用身份建构与语境的关系、语用身份建构与道德秩序的关系这几大方面分析和梳理现有的语用身份研究,以期为语用身份研究的进一步发展和理论体系的进一步完善提供一点参考。