A Bayesian Network approach to the evaluation of building design and its consequences for employee performance and operational costs

A Bayesian Network approach has been developed that can compare different building designs by estimating the effects of the thermal indoor environment on the mental performance of office workers. A part of this network is based on the compilation of subjective thermal sensation data and the associated objective thermal measurements from 12,000 office occupants from different parts of the world. A Performance Index (Π) is introduced that can be used to compare directly the different building designs and furthermore to assess the total economic consequences of the indoor climate with a specific building design. In this paper, focus will be on the effects of temperature on mental performance and not on other indoor climate factors. A total economic comparison of six different building designs, four located in northern Europe and two in Los Angeles, USA, was performed. The results indicate that investments in improved indoor thermal conditions can be justified economically in most cases. The Bayesian Network provides a reliable platform using probabilities for modelling the complexity while estimating the effect of indoor climate factors on human beings, due to the different ways in which humans are affected by the indoor climate.     

A performance-based approach to project assignment and performance evaluation

Project assignment and performance evaluation have been addressed as two important and separate research issues in project management. This paper develops a new performance-based approach for integrating the project assignment and the performance evaluation processes in a project-based organization. An objective-oriented preference-based assignment process is developed to assign a project to a project manager. An optimal project assignment model is developed to maximize the total weighted contribution value of all new projects to the organizational objectives. An efficiency-based evaluation process is developed using data envelopment analysis to measure the relative performance efficiency of the completed projects and of the project managers. The approach provides a proactive mechanism for facilitating objective-focused management of projects. The outcomes of an empirical study conducted provide managerial insights in assigning projects to project managers and in evaluating the performance efficiency of both projects and project managers.     

Galloping stability of triangular cross-sectional bodies: A systematic approach

One of the classical aeroelastic instabilities of slender structures is galloping, which can be characterized as a low-frequency, large-amplitude normal to the flow oscillations phenomenon. In this paper, the transverse galloping stability of triangular cross-section bodies has been systematically analyzed (up to now, most of the effort in galloping oscillation research has been concentrated on bodies with square or rectangular cross-sections). To perform such analysis, first, the Glauert–Den Hartog criterion for galloping instability was used through wind tunnel static tests. Then, another series of wind tunnel dynamic tests was realized to determine the transversal cross-section displacements as a function of the incident wind velocity. The results from these dynamic tests are in very good agreement with the results obtained from the static ones. Finally, information on the flow morphology needed for the physical interpretation of the results was obtained by measuring the pressure distribution along the body surfaces.     

Building signatures: A holistic approach to the evaluation of heating and cooling concepts

A sustainable and environmentally responsible building concept aims at a high workplace comfort, a significantly reduced heating and cooling demand, a high-efficient plant system, and the use of renewable energy sources to condition the built environment. This paper presents a comprehensive analysis of the heating and cooling concepts of 11 low-energy buildings in terms of energy use, efficiency and occupant thermal comfort. All buildings investigated employ environmental energy sources and sinks – such as the ground, ground water, rainwater and the ambient air – in combination with thermo-active building systems. A limited primary energy use of about 100 kWh_prim/(m²_neta) as a target for the complete building service technology (HVAC and lighting) was postulated for all buildings presented. With respect to this premise, a comprehensive long-term monitoring in high time resolution was carried out for two to five years, with an accompanying commissioning of the building performance. Measurements include the useful heating and cooling energy use, auxiliary energy use for the hydraulic system, as well as end and primary energy use, occupant thermal comfort and local meteorological conditions. A new methodology is proposed for a holistic approach to the evaluation of heating and cooling concepts, which not only considers the occupants thermal comfort, but also the useful energy consumption and the efficiency of the generation, distribution and delivery of heating and cooling energy.     

Data modelling and the application of a neural network approach to the prediction of total construction costs

Neural network cost models have been developed using data collected from nearly 300 building projects. Data were collected from predominantly primary sources using real-life data contained in project files, with some data obtained from the Building Cost Information Service, supplemented with further information, and some from a questionnaire distributed nationwide. The data collected included final account sums and, so that the model could evaluate the total cost to the client, clients' external and internal costs, in addition to construction costs. Models based on linear regression techniques have been used as a benchmark for evaluation of the neural network models. The results showed that the major benefit of the neural network approach was the ability of neural networks to model the nonlinearity in the data. The ‘best’ model obtained so far gives a mean absolute percentage error (MAPE) of 16.6%, which includes a percentage (unknown) for client changes. This compares favourably with traditional estimating where values of MAPE between 20.8% and 27.9% have been reported. However, it is anticipated that further analyses will result in the development of even more reliable models.     

Landscape impact analysis: a systematic approach to landscape impacts of policy

A method for analysis of landscape impacts and for presentation in visual terms was developed by the author and has been applied in Sweden and Norway to policy analysis. The method has successively been developed into a generalized method of landscape impact analysis of policies, programmes and plans — Landscape Impact Analysis (LIA). This deals with the interaction of human and natural systems and the resulting landscape. The method uses scenario techniques as a way of solving the problems of lack of specificity of policy, a problem which seems underestimated in the development of strategic environmental assessment. The paper describes the main steps of the method and shows examples of the application of the method to changes in Norwegian agricultural policy.     

A systematic evaluation of accelerating indoor airflow simulations using cross-platform parallel computing

With new advances in computer hardware and software, users now have widespread accessibility to multicore devices inside personal computers making it feasible for fast indoor airflow simulations. Some exciting preliminary results of a cross-platform parallel computing framework OpenCL using specific hardware were reported. However, those results are largely based on two hypotheses: 1. OpenCL code on all devices will generate the same results; 2. On the same device, running in parallel with multiple processors will be faster than running in sequential with a single processor. This study attempted to evaluate these two hypotheses by systematically studying the accuracy and computing speed of OpenCL for indoor airflow simulations. A Fast Fluid Dynamics (FFD) code was selected as an exemplar indoor airflow simulation program. To compare the cross-platform ability of OpenCL, the evaluation was performed using four Graphics Processing Units (GPUs) and five Central Processing Units (CPUs) from three manufacturers, with different degrees of computing capability and mounted on two operating systems. The test subjects were evaluated using four case studies consisting of various indoor airflows. A sequential FFD code programmed in C and a Computational Fluid Dynamics (CFD) program were first used to perform the case studies and generate numerical benchmarks. The comparison of the numerical simulation results with experimental data showed that CFD and FFD can predict the studied flows with averaged relative errors of 9.99% and 11.30%, respectively. Afterwards, the accuracy and speedup of the OpenCL code was compared with numerical benchmarks. Although the OpenCL code on the CPUs generated identical numerical results, the OpenCL results from the GPUs were slightly dissimilar. This is likely due to varying interpretations, by the manufactures, of an Institute of Electrical and Electronics Engineers standard. Depending on the hardware, the speedups of the OpenCL code varied from 0.7 to 4.2 times on the CPUs and 5.1–129.3 times on the GPUs. The slowdown of computing speed happened when running OpenCL on a two-core CPU in a Windows Operating System using the Boot Camp on a Mac computer. Finally, a separate study on the relationship between speedup and global work size showed that a speedup of 1139 can be achieved when using an AMD FirePro W8100 GPU.     

A systematic approach towards the structural behaviour of a lightweight deck–side shell system

Lightweight structures are increasingly used for high-speed ships. This paper presents a systematic approach to analyse the structural behaviour of a lightweight deck–side shell system using high strength steel. An analytical model of the deck–side shell system was first given, which includes the effects of stiffeners for the deck and side shell, the support conditions of the centreline girder (CL-girder), the influence of transverse beams, and the interaction between the side shell and the lightweight deck as parts of problems to the solution. By changing several geometric parameters, the sensitivity of both overall and local stress and deflection for the deck–side shell system was investigated. The different geometric parameters analysed comprise the influence for variation in the thickness of the web for transverse beams, longitudinal stiffeners and the CL-girder, the thickness of lower flange for the transverse beam and, the thickness for the panel. Furthermore, the influence of the lightweight deck and loads from the deck above on the side shell, the effects of the side shell and loads from top deck on the deck, the support conditions for the CL-girder, and the influence of deck loads on the eigenmodes were also analysed. By evaluating the results obtained from FE simulation, the support conditions of the CL-girder, the thickness of the panels and the lower flange of the transverse beams were found to be the most relevant parameters affecting both the stress and the deflection distribution of the structure. The dynamic characteristics of the structure were also analysed. The FE analysis concerning buckling of the structure was present. The results enable naval architects and structural engineers to design new extreme lightweight deck structure more reliable and economical. And some suggestions for future research are also given.     

浅谈DB总承包合同框架设计

DB总承包模式在国际工程领域已经被较为广泛地应用,而目前我国对该模式的应用仍处于刚起步阶段,各方面理论尚处于探索阶段。参照现代合同设计原则,并考虑到DB总承包合同文本的特殊性,提出了进行DB总承包合同框架设计的一些问题,在此基础上,提出了DB总承包合同框架的设计图,旨在为以后进一步的研究做一铺垫。     

A model approach to assess the long-term trends of indirect photochemistry in lake water. The case of Lake Maggiore (NW Italy)

A model-based approach is here developed and applied to predict the long-term trends of indirect photochemical processes in the surface layer (5 m water depth) of Lake Maggiore, NW Italy. For this lake, time series of the main parameters of photochemical importance that cover almost two decades are available. As a way to assess the relevant photochemical reactions, the modelled steady-state concentrations of important photogenerated transients (^•OH, ³CDOM* and CO₃^-•) were taken into account. A multivariate analysis approach was adopted to have an overview of the system, to emphasise relationships among chemical, photochemical and seasonal variables, and to highlight annual and long-term trends. Over the considered time period, because of the decrease of the dissolved organic carbon (DOC) content of water and of the increase of alkalinity, a significant increase is predicted for the steady-state concentrations of the radicals ^•OH and CO₃^−•. Therefore, the photochemical degradation processes that involve the two radical species would be enhanced. Another issue of potential photochemical importance is related to the winter maxima of nitrate (a photochemical ^•OH source) and the summer maxima of DOC (^•OH sink and ³CDOM* source) in the lake water under consideration. From the combination of sunlight irradiance and chemical composition data, one predicts that the processes involving ^•OH and CO₃^−• would be most important in spring, while the reactions involving ³CDOM* would be most important in summer.     

监理违约责任若干问题

对监理的履约,违约行为方式以及监理违约责任的适用归责原则进行了较为深入的研究,探讨了现行法律法规存在的问题,并就相关问题提出了自己的看法。     

Fixing the contract after the contract is fixed: A study of incomplete contracts in IT and construction projects

This paper aims to increase our understanding of collective outcomes by exploring both micro- and macro-level strategies for dealing with problems arising from incomplete contracts. By combining theories dealing with risk-sharing under various degrees of uncertainty (financial incentives and long-term relationships) with respect to social influence tactics involved in negotiations concerning additional work and changes, a useful framework was created. Case data regarding Swedish interorganizational development projects from both the construction and IT industries are used to illustrate the theoretical arguments. Findings indicate that social norms and the work-related values and attitudes of key negotiators significantly affect project outcomes. Efforts to increase the sophistication of financial incentives and long-term arrangements (e.g., standardized routines concerning risk-sharing and collaborative initiatives) do not seem to pay-off.     

A systematic validation of the Empathic Handover approach guided by five factors that foster empathy in design

Abstract

This study aims at validating the transferability of the Empathic Handover approach, which we originally developed for the co-design process of a dementia simulator. We argue that empathy in design is operationalised using five factors: emotional interest, sensitivity, self-awareness, personal experience, and mixed perspectives. This heuristic proved useful in systematically comparing the empathic capacity of design students using the Empathic Handover and traditional user research approaches. Our comparative study indicates that the Empathic Handover approach enables designers to develop empathy with vulnerable users they did not meet in person (both people with dementia and people who mourn). Additionally, the study enables us to develop an elaborate notion of the working mechanisms of empathy in design as well as practical improvements to the Empathic Handover approach.     

国际工程合同的发展趋势研究

通过分析近年来NEC合同与FIDIC合同条件所进行的调整和修订,特别是NECECC合同的发展变化,总结国际工程合同的发展趋势,作为设计工程合同体系、编写工程合同条件时的借鉴。     

加强建筑工程合同管理的有效措施

分析了我国目前工程合同履行中存在的问题,同时参照国际FIDIC合同条件,结合目前我国实施工程量清单模式的合同管理可能出现的情况,对加强建筑工程合同管理的有效措施进行了探讨.     

A statistical approach for the evaluation of the thermal behavior of dry assembled PCM containing walls

Adequate estimation of the energetic improvements which derived from the insertion of phase change materials (PCM) inside light dry assembled walls is an important step in order to quantify the comfort advantages that can derive from the use of such materials. The use of a statistic approach based fundamentally on the time series analysis method may represent a valid information instrument in support of all the technical analysis carried out in order to evaluate the effects of thermal inertia increase on the heat transmission process that occurs between the elements of a building. PCM containing walls, tested at the “Renewable Energies Outdoor Laboratory” of the Polytechnic University of Marche during the summer of 2003, present delicate problems relative to the identification of physical models relating to dynamics of heat exchange between building components. The application of a vector auto regressive (VAR) estimation model allows, using high frequency experimental data, obtaining consistent estimates regarding the physical phenomenon of energy exchange which intervene inside buildings—both between the walls, and through the walls—occurring during the observation period. The results of this approach are twofold: firstly, they demonstrate the existence of statistically significant linear dependencies among the variables used, and secondly, they highlight the comfort conditions’ improvements due to the insertion of PCM inside dry assembled walls.