bluuebunny/crossref_metadata_2025 huggingface dataset:
Globalization, corporate social responsibility and human rights
Authors: Welford Richard
Published: January 2005

In extending this journal to include issues of corporate social responsibility, we have come to recognize and reflect the fact that in order to move towards sustainable development we must examine social, environmental and economic issues. In this journal we have in the past demonstrated how companies can benefit from the use of environmental management tools and strategies. Now we extend the debate to social issues. However, corporate social responsibility tends to be much more controversial than improving environmental performance. Social responsibility requires us to look at ethics, stakeholder accountability and our own value systems. There will often be contradictory positions taken on some social issues and stakeholders will not always agree with each other. One starting point that seems productive however is to see corporate social responsibility in the context of human rights. This article therefore lays out how we can use the process of globalization to improve human rights through business activity and commitment. Copyright © 2002 John Wiley & Sons, Ltd and ERP Environment
Stakeholder accountability or stakeholder management: a review of UK firms' social and ethical accounting, auditing and reporting (SEAAR) practices
Authors: Belal Ataur Rahman
Published: January 2005

The main aim of this study is to undertake an evaluation of the initial wave of stand‐alone social reports issued by the major market players in the UK using AA1000 as an evaluative tool, or benchmark, in order to ascertain the extent to which they conform to the provisions of AA1000, in particular the core principles of accountability and inclusivity. Applying the lens of the stakeholder model the paper examines to what extent contemporary SEAAR practices in the UK are likely to promote stakeholder accountability, or whether they are simply exercises in stakeholder management. Copyright © 2002 John Wiley & Sons, Ltd and ERP Environment.
Communication in corporate environmental reports
Authors: Cerin Pontus
Published: January 2005

Since the beginning of the 1990s the number of companies producing environmental reports has increased considerably, a rise that now has reached a plateau. Some critics claim environmental reports are merely an exercise in public relations. This study describes the ascent of and the motives behind corporate environmental reporting and examines the extent to which the messages communicated in environmental reports correlate with the messages contained in corresponding annual reports and actual corporate behaviour. The indicated praxis of steering attention away from environmental problems—a by‐pass solution—can involve providing contradictory information to various stakeholders. This article looks into third‐party verification impacts on the credibility of environmental reports and calls for stricter reporting rules. The paper also discusses how eco‐efficiency and sustainability demands placed on the scope of environmental reporting could enhance the sustainability of this reporting phenomenon, by for example doing away with merely limiting reports to company‐judicial borders. Copyright © 2002 John Wiley & Sons, Ltd and ERP Environment
The dominant economics paradigm and corporate social responsibility
Authors: Korhonen Jouni
Published: January 2005

For many centuries, industrial societies in the Western modernity have been driven by a dominant social paradigm (DSP). It is argued in this paper that this paradigm has some serious difficulties in the light of the development of the field of corporate social responsibility and in the light of its practice. Therefore, a new paradigmatic foundation is required for corporate social responsibility. The dominant social paradigm is contrasted with metaphors and principles that are derived from sources that are outside the paradigmatic basis of Western modernity, and outside the paradigm of neoclassical economics. These new metaphors and principles may be suitable for further development of the corporate social responsibility paradigm as well as for reconsideration of the economics paradigm. Copyright © 2002 John Wiley & Sons, Ltd and ERP Environment
Heuristic and simulated annealing algorithms for solving extended cell assignment problem in wireless ATM networks
Authors: Din Der‐Rong , Tseng S. S.
Published: January 2005

In this paper, we investigate the extended cell assignment problem which optimally assigns new adding and splitting cells in Personal Communication Service (PCS) to switches in a wireless Asynchronous Transfer Mode (ATM) network. Given cells in a PCS network and switches on an ATM network (whose locations are fixed and known), we would like to do the assignment in an attempt to minimize a cost criterion. The cost has two components: one is the cost of handoffs that involve two switches, and the other is the cost of cabling. This problem is modeled as a complex integer programming problem, and finding an optimal solution to this problem is NP‐hard. A heuristic algorithm and a simulated annealing algorithm are proposed to solve this problem. The heuristic algorithm, Extended Assignment Algorithm (EEA), consists of two phases, initial assigning phase and cell exchanging phase. First, in the initial assigning phase, the initial assignments of cells to switches are found. Then, these assignments are improved by performing cell exchanging phase in which two cells are repeatedly exchanged in different switches with great reduction of the total cost. The simulated annealing algorithm, ESA (enhanced simulated annealing), generates constraint‐satisfied configurations, and uses three configuration perturbation schemes to change current configuration to a new one. Experimental results indicate that EAA and ESA algorithms have good performances. Copyright © 2002 John Wiley & Sons, Ltd.
EMAS and regulatory relief in Europe: lessons from national experience
Authors: Wätzold Frank , Bültmann Alexandra , Eames Malcolm , Lulofs Kris , Schucht Simone
Published: January 2005

Apart from in Germany and Austria, corporate participation in the European Eco‐Management and Audit Scheme (EMAS) has remained sluggish and far behind involvement in ISO14001. Given the lack of response in most EU member states, the key issue for the current EMAS revision is to increase incentives for companies to join the scheme. One of the proposals in this respect is to encourage member states to consider a lighter regulatory touch for EMAS participants. The aim of this article is to assess the extent to which encouraging regulatory relief may contribute to an increase in the number of EMAS registered companies. For this purpose the regulatory relief already offered to EMAS registered (and ISO14001 certified) companies in France, Germany, The Netherlands and the United Kingdom is described and analysed. Based on this experience, the central conclusion of the article is that regulatory relief can increase participation in EMAS, but that to do so it must be granted exclusively to EMAS registered companies, and that ideally such relief should be substantial and integrated into a comprehensive voluntary policy approach aimed at altering the traditional relationship between government and industry. However, given that some countries treat EMAS registration and ISO14001 certification as equivalent, with respect to regulatory relief, even those deregulation measures that fulfil the above conditions may lead to an increase in ISO14001 certifications rather than EMAS registrations. Copyright © 2001 John Wiley & Sons, Ltd and ERP Environment.
Paradoxes of conservation and development in postsocialist Bulgaria: recent controversies
Authors: Staddon Caedmon , Cellarius Barbara
Published: January 2005

Based on extensive primary research in the 1990s a number of contemporary Bulgarian environmental controversies are examined, which highlight some of the paradoxes of sustainable development in a postsocialist context. Water sector controversies such as the Djerman‐Skakavitsa diversion project forest and national park and other protected area management controversies in the Rila and Pirin National Parks and the Rhodope mountains are sketched. Extension and creation of new protected areas presents both challenges and opportunities to local residents and conservation agencies alike but creative solutions are at least being considered within a framework of sustainable regional development. It is found that dependence on natural resource hinterlands for commodity and non‐commodity uses provides for new, complex and contested regulation between stakeholders and the postsocialist state at a variety of scales from the local to the global, with nested though mutable, scale‐dependent relations. Copyright © 2002 John Wiley & Sons, Ltd. and ERP Environment.
Ketonization of Carboxylic Acids by Decarboxylation: Mechanism and Scope
Authors: Renz Michael
Published: January 2005

In the ketonic decarboxylation process, a ketone is formed from two moles of carboxylic acid; water and carbon dioxide are produced as side‐products. At present, the mechanism of this reaction remains under debate; it has been proposed as a radical mechanism, a mechanism involving a ‐keto acid as intermediate, or a concerted mechanism. This paper demonstrates that the latter mechanism is the most likely one and that weak bases may play the role of promoters. Different processes are reviewed for the syntheses of the following ketones: symmetrical ketones, such as acetone or 3‐pentanone, cyclic ketones, such as cyclopentanone (parent compound and substituted derivatives), fatty ketones, and some unsymmetrical ketones. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Density estimation in line transect sampling with grouped data by local least squares
Authors: Barabesi Lucio , Greco Luigi , Naddeo Stefania
Published: January 2005

A semiparametric estimator for animal density in distance sampling is proposed when grouped data are on hand. The estimation technique is based on a kernel‐smoothed local least‐square criterion function, suitably developed for this setting. The new method presents interesting theoretical properties and it produces accurate and robust estimators, as is shown in a Monte Carlo study. Copyright © 2002 John Wiley & Sons, Ltd.
Time‐delay effect and compensation on direct output feedback controlled mass damper systems
Authors: Chu S. Y. , Soong T. T. , Lin C. C. , Chen Y. Z.
Published: January 2005

In active control, the control force execution time delay cannot be avoided or eliminated even with present technology, which can be critical to the performance of the control system. This paper investigates the influence of time delay on the stability of an SDOF system with an optimal direct output feedback controlled mass damper. An active mass damper system can take the form of a hybrid mass damper (HMD) or a fully active mass damper (AMD) depending upon imposed design constraints resulting from space, strength and power limitations. Explicit formulas and numerical solutions to determine the maximum delay time which causes onset of system instability are obtained. The control effect of the two‐DOF HMD/AMD benchmark system with and without time delay is illustrated quantitatively in a continuous‐time approach. In order to fit the digital implementation of the computer‐controlled system in practice, the control gains will be compensated by using their discrete‐time version to overcome the degradation of control effect due to time delay. Copyright © 2001 John Wiley & Sons, Ltd.
Cyclic analysis and capacity prediction of concrete‐filled steel box columns
Authors: Susantha K. A. S. , Ge Hanbin , Usami Tsutomu
Published: January 2005

Concrete‐filled steel columns have been widely used in civil and architectural constructions throughout the world in recent years. This study is concerned with the cyclic elastoplastic analysis and capacity prediction of concrete‐filled steel columns having thick‐ and thin‐walled stiffened box‐shaped sections. An analytical procedure for determining the ultimate state of the concrete‐filled steel column is proposed based on the fiber analysis technique. Strength and ductility predictions are made by means of a new failure criterion. This is proposed based on the average failure strain of concrete and steel at critical regions. A recently developed monotonic stress–strain relation for confined concrete is modified so that it can be used in the analysis of thin‐ or thick‐walled section columns with stiffeners. A simple cyclic rule is introduced into this model in order to be used in cyclic analysis. Material non‐linearity of steel is represented by the modified two surface model developed at Nagoya University. The predictions are then compared with the existing experimental results and found to exhibit satisfactory agreement. Both small‐ and large‐scaled columns are considered in the comparisons. Copyright © 2001 John Wiley & Sons, Ltd.
Structural damage detection using the optimal weights of the approximating artificial neural networks
Authors: Hung Shih‐Lin , Kao C. Y.
Published: January 2005

This work presents a novel neural network‐based approach to detect structural damage. The proposed approach comprises two steps. The first step, system identification, involves using neural system identification networks (NSINs) to identify the undamaged and damaged states of a structural system. The partial derivatives of the outputs with respect to the inputs of the NSIN, which identifies the system in a certain undamaged or damaged state, have a negligible variation with different system errors. This loosely defined unique property enables these partial derivatives to quantitatively indicate system damage from the model parameters. The second step, structural damage detection, involves using the neural damage detection network (NDDN) to detect the location and extent of the structural damage. The input to the NDDN is taken as the aforementioned partial derivatives of NSIN, and the output of the NDDN identifies the damage level for each member in the structure. Moreover, SDOF and MDOF examples are presented to demonstrate the feasibility of using the proposed method for damage detection of linear structures. Copyright © 2001 John Wiley & Sons, Ltd.
Applicability of the H/V spectral ratio of microtremors in assessing site effects on seismic motion
Authors: Rodriguez Victor H. S. , Midorikawa Saburoh
Published: January 2005

The authors examine the reliability of site response estimations obtained by the horizontal to vertical (H/V) spectral ratios of microtremors by means of cross‐validation with the ratio of the horizontal spectra of earthquake motion with respect to reference sites. The data comprise microtremor and ground motion records recorded at 150 sites of Yokohama strong motion array. The use of non‐supervised pattern recognition techniques aims to group the sites with more objectivity. Attributes defining the overall shape of the amplification spectra serve as input in the computation of Euclidean distance similarity coefficients amongst sites. The implementation of the Ward clustering scheme leads to the attainment of a meaningful tree diagram. Its analysis shows the possibility of summarizing the results into six general patterns. A good coincidence of site effects estimates at 80 per cent of the sites becomes apparent. However, this coincidence appears poor for sites characterized by H/V amplification ratios around 2 or smaller and predominant periods longer than 0.5 s. In such cases, the presence of stiff, sandy sediments in the soil profile proves common. To proscribe H/V estimations, relying solely on the small spectral ratios criterion seems inadequate. Copyright © 2001 John Wiley & Sons, Ltd.
Seismic response of rail‐counterweight systems in elevators
Authors: Singh Mahendra P. , Suarez Luis E. , Rildova
Published: January 2005

The rail‐counterweight systems in building elevators are known to be susceptible to earthquake‐induced ground motions. Besides avoiding costly repairs and economic disruptions, it is of special interest to maintain the functionality of the elevators in critical facilities such as hospitals during, and especially after, a strong earthquake event. This paper presents an approach to develop a realistic analytical model of these vulnerable systems to study their seismic response behaviour. The model includes the flexibilities of the guidance and supporting components of the counterweights in a systematic manner. Currently only the linear response behaviour is considered; however, the sources of non‐linearities in the flexible components are clearly identified. The model considers the effect of the differential support motions from the building. Both the out‐of‐plane and in‐plane responses of the rail‐counterweight are studied and included in the stress calculations. Several sets of numerical results considering simultaneous action of the two orthogonal components of historic earthquakes are obtained to study the seismic response characteristics of the rail‐counterweight system. Copyright © 2001 John Wiley & Sons, Ltd.
Analytical model of structures with frictional pendulum isolators
Authors: Almazán José L. , De la Llera Juan C.
Published: January 2005

This investigation centres on the development of a mathematically formal description of the dynamic response of structures isolated with the frictional pendulum system (FPS). It is shown that a theoretically ‘exact’ model can be formulated to account for large deformation kinematics and the associated P–Δ effects in the isolators. The problem is of importance in light of the large deformations observed during impulsive ground motions like those that occurred during the Northridge, Kobe, Turkey, and Taiwan earthquakes. Besides, the model developed may be easily extended to other devices with kinematic constraints other than the spherical one corresponding to the FPS. Results of the model are presented for two building examples. The first one deals with the seismic response of a rigid superstructure supported on two FPS isolators and is intended to provide a numerical example of the equations developed in the text. The second example presents the three‐dimensional earthquake response of a nominally symmetric structure supported on four FPS isolators and subjected to different ground motions. Both examples point out that small deformation kinematics may lead, in the case of impulsive motions, to discrepancies in global response quantities, relative to the ‘actual’ response, as large as 30 per cent. These discrepancies increase up to 50 per cent for local response quantities such as normal isolator forces. Copyright © 2001 John Wiley & Sons, Ltd.
Extraction of hysteretic properties of seismically isolated bridges from quick‐release field tests
Authors: Chen Qingbin , Douglas Bruce M. , Maragakis Emmanuel A. , Buckle Ian G.
Published: January 2005

A simple procedure for identifying hysteretic properties of seismically isolated bridges from full‐scale quick‐release tests is presented in this paper. An analytical solution for the quick‐release response of a SDOF system with a bilinear spring is derived. Based on the solution, some characteristics of such systems are obtained. A time domain optimization method is employed to identify the hysteretic properties of the lead–rubber bearings installed in seismically isolated bridges. The total damping effects of the isolation system are expressed as a combination of the rate‐independent (hysteretic) damping and the linear viscous damping. The Menegotto–Pinto (MP) model and bilinear model are used to represent the force–displacement relation of the lead–rubber bearings. In both the longitudinal and transverse directions the bridges have been idealized as single degree of freedom (SDOF) systems. Time histories recorded from the field quick‐release tests on two bridges are used for the examples presented herein. The hysteretic loops of the isolators obtained from laboratory tests are compared with those obtained using the optimization method, and they agree well. In conclusion, the procedure shown in this paper can be used to identify the essential in situ hysteretic characteristics of isolation bearings from quick‐release field testing. Copyright © 2001 John Wiley & Sons, Ltd.
Effect of masonry infills on seismic performance of a 3‐storey R/C frame with non‐seismic detailing
Authors: Lee Han‐Seon , Woo Sung‐Woo
Published: January 2005

The objective of this study is to investigate the effect of masonry infills on the seismic performance of low‐rise reinforced concrete (RC) frames with non‐seismic detailing. For this purpose, a 2‐bay 3‐storey masonry‐infilled RC frame was selected and a 1 : 5 scale model was constructed according to the Korean practice of non‐seismic detailing and the similitude law. Then, a series of earthquake simulation tests and a pushover test were performed on this model.

When the results of these tests are compared with those in the case of the bare frame, it can be recognized that the masonry infills contribute to the large increase in the stiffness and strength of the global structure whereas they also accompany the increase of earthquake inertia forces. The failure mode of the masonry‐infilled frame was that of shear failure due to the bed‐joint sliding of the masonry infills while that of the bare frame appeared to be the soft‐storey plastic mechanism at the first storey. However, it is judged that the masonry infills can be beneficial to the seismic performance of the structure since the amount of the increase in strength appears to be greater than that in the induced earthquake inertia forces while the deformation capacity of the global structure remains almost the same regardless of the presence of the masonry infills. Copyright © 2001 John Wiley & Sons, Ltd.
Tuned mass dampers for response control of torsional buildings
Authors: Singh Mahendra P. , Singh Sarbjeet , Moreschi Luis M.
Published: January 2005

This paper presents an approach for optimum design of tuned mass dampers for response control of torsional building systems subjected to bi‐directional seismic inputs. Four dampers with fourteen distinct design parameters, installed in pairs along two orthogonal directions, are optimally designed. A genetic algorithm is used to search for the optimum parameter values for the four dampers. This approach is quite versatile as it can be used with different design criteria and definitions of seismic inputs. It usually provides a globally optimum solution. Several optimal design criteria, expressed in terms of performance functions that depend on the structural response, are used. Several sets of numerical results for a torsional system excited by random and response spectrum models of seismic inputs are presented to show the effectiveness of the optimum designs in reducing the system response. Copyright © 2002 John Wiley & Sons, Ltd.
A mathematical hysteretic model for elastomeric isolation bearings
Authors: Hwang J. S. , Wu J. D. , Pan T.‐C. , Yang G.
Published: January 2005

An analytical model for high damping elastomeric isolation bearings is presented in this paper. The model is used to describe mathematically the damping force and restoring force of the rubber material and bearing. Ten parameters to be identified from cyclic loading tests are included in the model. The sensitivity of the ten parameters in affecting the model is examined. These ten parameters are functions of a number of influence factors on the elastomer such as the rubber compound, Mullins effect, scragging effect, frequency, temperature and axial load. In this study, however, only the Mullins effect, scragging effect, frequency and temperature are investigated. Both material tests and shaking table tests were performed to validate the proposed model. Based on the comparison between the experimental and the analytical results, it is found that the proposed analytical model is capable of predicting the shear force–displacement hysteresis very accurately for both rubber material and bearing under cyclic loading reversals. The seismic response time histories of the bearing can also be captured, using the proposed analytical model, with a practically acceptable precision. Copyright © 2002 John Wiley & Sons, Ltd.
Performance‐based design with semi‐active structural control technique
Authors: Kurata Narito , Kobori Takuji , Koshika Norihide
Published: January 2005

The recent spate of large earthquakes has triggered diverse performance requirements for structures. This has led to increasing worldwide interest in performance‐based design methods. To establish such methods, however, it is necessary to evaluate structure conditions after defining the loads, and this is difficult to accomplish. On the other hand, there has been steady progress on research and development of structural control techniques for improving structural performance. These technological innovations need to be rationally incorporated into structural design. In particular, semi‐active structural control techniques are effective in improving structural performance during large earthquakes. By effectively incorporating them into the design, it is possible to meet the various structural performance requirements. This paper first outlines the various structural control methods and focuses on the semi‐active structural control technique as the main topic. It then describes an example to verify the effectiveness of the semi‐active structural control technique in high‐rise buildings. Copyright © 2001 John Wiley & Sons, Ltd.
Investigations into critical earthquake load models within deterministic and probabilistic frameworks
Authors: Abbas A. M. , Manohar C. S.
Published: January 2005

This paper deals with the determination of critical earthquake load models for linear structures subjected to single‐point seismic inputs. The primary objective of this study is to examine the realism in critical excitations and critical responses vis a vis the framework adopted for the study and constraints that these excitations are taken to satisfy. Two alternative approaches are investigated. In the first approach, the critical earthquake is expressed in terms of a Fourier series that is modulated by an enveloping function that imparts transient nature to the inputs. The Fourier coefficients are taken to be deterministic and are constrained to satisfy specified upper and lower bounds. Estimates on these bounds, for a given site, are obtained by analysing past earthquake records from the same site or similar sites. The unknown Fourier coefficients are determined such that the response of a given structure is maximized subjected to these bounds and additional constraints on intensity, peak ground acceleration, peak ground velocity and peak ground displacement. In the second approach, the critical earthquake is modelled as a partially specified non‐stationary Gaussian random process which is defined in terms of a stationary random process of unknown power spectral density (psd) function modulated by a deterministic envelope function. The input is constrained to possess specified variance and average zero crossing rate. Additionally, a new constraint in terms of entropy rate representing the expected level of disorder in the excitation is also imposed. The unknown psd function of the stationary part of the input is determined so that the response of a given structure is maximized. The optimization problem in both these approaches is solved by using sequential quadratic programming method. The procedures developed are illustrated by considering the seismic response of a tall chimney and an earth dam. It is concluded that the imposition of lower and upper bounds on Fourier coefficients in the first approach and constraints on amount of disorder in the second approach are crucial in arriving at realistic critical excitations. Copyright © 2002 John Wiley & Sons, Ltd.
Risk assessment of an interacting structure–soil system due to liquefaction
Authors: Koutsourelakis Steve , Prévost Jean H. , Deodatis George
Published: January 2005

The present study deals with the non‐linear stochastic dynamic analysis of a soil–structure interacting system. The ultimate objective is to determine the risk of damage to the system due to liquefaction under a wide range of earthquake intensities. A Monte Carlo simulation approach is followed in conjunction with advanced finite element procedures. The stochastic spatial variability of soil properties and the randomness of the seismic excitation are taken into account in order to estimate the statistics of the response, measured in terms of uniform foundation settlement and tilting. Specifically, soil properties are modelled as non‐Gaussian random fields and seismic excitations as non‐stationary random processes. The probabilistic characteristics of the stochastic field modelling soil properties are established from in situ tests. The risk of damage to the soil–structure system due to liquefaction is assessed by establishing fragility curves, which are of paramount importance for risk assessment and management studies of such systems. Fragility curves express the probability of exceeding various thresholds in the response. The relative effect of the variability of various soil parameters on the variability of the response is also examined. Copyright © 2002 John Wiley & Sons, Ltd.
Displacement‐based seismic analysis for out‐of‐plane bending of unreinforced masonry walls
Authors: Doherty K. , Griffith M. C. , Lam N. , Wilson J.
Published: January 2005

This paper addresses the problem of assessing the seismic resistance of brick masonry walls subject to out‐of‐plane bending. A simplified linearized displacement‐based procedure is presented along with recommendations for the selection of an appropriate substitute structure in order to provide the most representative analytical results. A trilinear relationship is used to characterize the real nonlinear force–displacement relationship for unreinforced brick masonry walls. Predictions of the magnitude of support motion required to cause flexural failure of masonry walls using the linearized displacement‐based procedure and quasi‐static analysis procedures are compared with the results of experiments and non‐linear time‐history analyses. The displacement‐based procedure is shown to give significantly better predictions than the force‐based method. Copyright © 2002 John Wiley & Sons, Ltd.
Fuzzy sliding mode control for a building structure based on genetic algorithms
Authors: Wang An‐Pei , Lee Chen‐Der
Published: January 2005

Based on the genetic algorithms (GAs), a fuzzy sliding mode control (FSMC) method for the building structure is designed in this research. When a fuzzy logic control method is used for a structural system, it is hard to get proper control rules directly, and to guarantee the stability and robustness of the fuzzy control system. Generally, the fuzzy controller combined with sliding mode control is applied, but there is still no criterion to reach an optimal design of the FSMC. In this paper, therefore, we design a fuzzy sliding mode controller for the building structure control system as an optimization problem and apply the optimal searching algorithms and GAs to find the optimal rules and membership functions of the FSMC. The proposed approach has the merit to determine the optimal structure and the inference rules of fuzzy sliding mode controller simultaneously. It is found that the building structure under the proposed control method could sustain in safety and stability when the system is subjected to external disturbances. Copyright © 2002 John Wiley & Sons, Ltd.
Optimum multiple tuned mass dampers for structures under the ground acceleration based on DDMF and ADMF
Authors: Li Chunxiang
Published: January 2005

Multiple tuned mass dampers (MTMD) consisting of many tuned mass dampers (TMDs) with a uniform distribution of natural frequencies are taken into consideration for attenuating undesirable vibration of a structure under the ground acceleration. A study is conducted to search for the preferable MTMD which performs better and is easily manufactured from the five available models (i.e. MTMD‐1 – MTMD‐5), which comprise various combinations of the stiffness, mass, damping coefficient and damping ratio in the MTMD. The major objective of the present study then is to evaluate and compare the control performance of these five models. The structure is represented by its mode‐generalized system in the specific vibration mode being controlled by adopting the mode reduced‐order approach. The optimum parameters of the MTMD‐1 – MTMD‐5 are investigated to reveal the influence of the important parameters on their effectiveness and robustness using a numerical searching technique. The parameters include the frequency spacing, average damping ratio, tuning frequency ratio, mass ratio and total number. The criteria selected for the optimum searching are the minimization of the maximum value of the displacement dynamic magnification factor (DDMF) and that of the acceleration dynamic magnification factor (ADMF) of the structure with the MTMD‐1 – MTMD‐5 (i.e. Min.Max.DDMF and Min.Max.ADMF). It is demonstrated that the optimum MTMD‐1 and MTMD‐4 yield approximately the same control performance, and offer higher effectiveness and robustness than the optimum MTMD‐2, MTMD‐3, and MTMD‐5 in reducing the displacement and acceleration responses of structures. It is further demonstrated that for both the best effectiveness and robustness and the simplest manufacturing, it is preferable to select the optimum MTMD‐1. Copyright © 2002 John Wiley & Sons, Ltd.
Optimal design of passive energy dissipation systems based on H∞ and H2 performances
Authors: Yang J. N. , Lin S. , Kim J‐H. , Agrawal A. K.
Published: January 2005

Passive energy dissipation devices (EDDs), such as viscous dampers, viscoelastic dampers, etc., have been used to effectively reduce the dynamic response of civil infrastructures, such as buildings and bridges, subject to earthquakes and strong winds. The design of these passive energy dissipation devices (EDDs) involves the determination of the optimal locations and the corresponding capacities. In this paper, we present two optimal design methodologies for passive EDDs based on active control theories, including H∞ and H2 performances, respectively. The optimal design methodologies presented are capable of determining the optimal locations and the corresponding capacities of EDDs. Emphasis is placed on the application of linear matrix inequality (LMI) for the effective design of passive EDDs using the popular MATLAB toolboxes. One important advantage of the proposed approaches is that the computation of the structural response is not needed in the design process. The proposed optimal design methodologies have been applied to: (i) a 10‐storey building and a 24‐storey building both subject to earthquake excitations, and (ii) a 76‐storey wind‐excited benchmark building, to demonstrate the advantages of the proposed design methodologies over the conventional equal capacity design. Copyright © 2002 John Wiley & Sons, Ltd.
A new modelling strategy for the behaviour of shear walls under dynamic loading
Authors: Mazars J. , Kotronis P. , Davenne L.
Published: January 2005

A new simplified modelling strategy to simulate the non‐linear behaviour of reinforced concrete shear walls under dynamic loading is presented. The equivalent reinforced concrete (ERC) model is derived from the framework method and uses lattice meshes for concrete and reinforcement bars and uniaxial constitutive laws based on continuum damage mechanics and plasticity. Results show the capacity of the model to analyse structures having different slenderness and boundary conditions. For low reinforcement ratios however, results are sensitive to the angle formed by the diagonals of the concrete lattice and the horizontal bars. The method is compared with the shear multi‐layered beam model that uses Timoshenko multi‐layered 2D beam elements and biaxial constitutive laws. Comparisons for both models with experimental results of two research programs (one organized by NUPEC and the other by COGEMA and EDF) are provided. ERC is a simplified method that intends to save computer time and allows parametrical studies. Copyright © 2002 John Wiley & Sons, Ltd.
Optimal placement of dampers for passive response control
Authors: Singh Mahendra P. , Moreschi Luis M.
Published: January 2005

The effectiveness of viscous and viscoelastic dampers for seismic response reduction of structures is quite well known in the earthquake engineering community. This paper deals with the optimal utilization of these dampers in a structure to achieve a desired performance under earthquake‐induced ground excitations. Frequency‐dependent and ‐independent viscous dampers and viscoelastic dampers have been considered as the devices of choice. To determine the optimal size and location of these dampers in the structure, a genetic algorithm is used. The desired performance is defined in terms of several different forms of performance functions. The use of the genetic approach is not limited to any particular form of performance function as long as it can be calculated numerically. For illustration, numerical examples for different building structures are presented showing the distribution and size of different dampers required to achieve a desired level of reduction in the response or a performance index. Copyright © 2002 John Wiley & Sons, Ltd.
Simulations of non‐stationary frequency content and its importance to seismic assessment of structures
Authors: Wang Junjie , Fan Lichu , Qian Shie , Zhou Jing
Published: January 2005

To verify the importance of the non‐stationary frequency characteristic of seismic ground motion, a joint time–frequency analysis technique of time signals, called chirplet‐based signal approximation, is developed to extract the non‐stationary frequency information from the recorded data. The chirplet‐based signal approximation is clear in concept, similar to Fourier Transform in mathematical expressions but with different base functions. Case studies show that the chirplet‐based signal approximation can represent the joint time–frequency variation of seismic ground motion quite well. Both the random models of uniform modulating process and evolutionary process are employed to generate artificial seismic waves. The joint time–frequency modulating function in the random model of evolutionary process is determined by chirplet‐based signal approximation. Finally, non‐linear response analysis of a SODF system and a frame structure is performed based on the generated artificial seismic waves. The results show that the non‐stationary frequency characteristic of seismic ground motion can significantly change the non‐linear response characteristics of structures, particularly when a structure goes into collapse phase under seismic action. It is concluded that non‐stationary frequency characteristic of seismic ground motion should be considered for the assessment of seismic capacity of structures. Copyright © 2002 John Wiley & Sons, Ltd.
Probabilistic approach for modal identification using non‐stationary noisy response measurements only
Authors: Yuen Ka‐Veng , Beck James L. , Katafygiotis Lambros S.
Published: January 2005

This paper addresses the problem of identification of the modal parameters for a structural system using measured non‐stationary response time histories only. A Bayesian time‐domain approach is presented which is based on an approximation of the probability distribution of the response to a non‐stationary stochastic excitation. It allows one to obtain not only the most probable values of the updated modal parameters and stochastic excitation parameters but also their associated uncertainties using only one set of response data. It is found that the updated probability distribution can be well approximated by a Gaussian distribution centred at the most probable values of the parameters. Examples using simulated data are presented to illustrate the proposed method. Copyright © 2002 John Wiley & Sons, Ltd.
Dynamic analysis method of a combined energy dissipation system and its experimental verification
Authors: Lu Xilin , Zhou Qiang
Published: January 2005

A combined energy dissipation system is developed in this paper. In this system lead rubber dampers and their parallel connection with oil dampers are used in the braces of a structural frame. A dynamic analysis method of the system, including the modelling of the lead rubber damper and the oil damper, is proposed. In the analysis method, the restoring force characterestics of the lead rubber damper is simulated by the Bouc–Wen hysteretic model, and the behaviour of the oil damper is simulated by a velocity and displacement‐related model in which the contributions of the oil damper to the damping force and stiffness of the system are considered. A series of shaking table tests of a three‐storey steel frame with the combined energy dissipation system are carried out to evaluate the performance of the system and to verify the analysis method. The test and analysis show that the performance of the combined energy dissipation system is quite satisfactory and there is a good agreement between the analysis and test results, which indicates that the analysis method proposed in this paper is valid and suitable for the dynamic analysis of the combined energy dissipation system. Copyright © 2002 John Wiley & Sons, Ltd.
Bankfull discharge in mountain streams: theory and practice
Authors: Radecki‐Pawlik Artur
Published: January 2005

The results are presented of an investigation of bankfull discharge in two Polish Carpathian streams: Skawica and Krzyworzeka. Existing definitions of river bankfull were reviewed and applied in tests carried out on selected cross‐sections of the streams. The Woodyer method was given special attention, with a correspondingly detailed survey of plants characterizing river benches. Riley's bench index method and the methods of Williams, Wolman, Schumm and Brown, and Woloszyn were tested. The report concludes that bankfull discharge value for a mountain stream should not be reported as a single number, but rather as a range of discharges within which one could expect the bankfull value to lie. Copyright © 2002 John Wiley & Sons, Ltd.
Rates of development of tafoni in the Moenkopi and Kaibab formations in Meteor Crater and on the Colorado Plateau, northeastern Arizona
Authors: Norwick Stephen A. , Dexter Leland R.
Published: January 2005

Tafoni are pits formed by non‐uniform weathering in otherwise uniform rock. Two equations have been proposed for the rate of development of tafoni, both based on 2000‐year‐old outcrops from the coast of Japan. We have taken tafoni measurements from the Meteor Crater, Arizona, and vicinity that extend the equations back at least 50 000 years. As reported in earlier studies, we found pit depth to be the best tafone parameter to measure. The size of the pit decreases significantly with increasing inclination of the rock surface; however, the size of the pit can vary greatly for other reasons. In some cases the measurements are statistically significantly different between two stations taken from contiguous areas of similar inclination and aspect in an apparently homogeneous bed. It is clear, however, that over tens of thousands of years tafoni enlarge significantly. Our data are generally log‐normal and all are markedly heteroscedastic. The 1991 equation proposed by Matsukura and Matsuoka does not fit our data. The 1996 equation proposed by Sunamura provides a better fit. We propose a sigmoidal equation D = b1 + e(b2+(b3/t)) where D is the depth, t is the age, and b1, b2 and b3 vary with lithology. This new equation fits our data far better than the earlier published equations. Copyright © 2002 John Wiley & Sons, Ltd.
Insights into river bank erosion processes derived from analysis of negative erosion‐pin recordings: observations from three recent UK studies
Authors: Couper Pauline , Stott Tim , Maddock Ian
Published: January 2005

Recent studies of river bank erosion in three catchments in the UK have been characterized by the persistent occurrence of negative erosion‐pin results. The cause of these negative recordings is considered with reference to field data from the Afon Trannon, Nant Tanllwyth and River Arrow, and to a laboratory study of freeze–thaw and desiccation processes. It seems that there is potential for, and in some cases evidence of, a number of different circumstances that generate negative results, but none of these alone is sufficient to explain all incidents. Factors considered include: deposition of sediment during high flows; soil fall from the upper parts of the bank on to lower erosion pins; loosening of the soil surface and expansion/contraction of the soil mass with fluctuations in temperature and moisture content; movement of the erosion‐pin within the bank and human interference. Each has its own implications for the use of erosion pins.

Further issues arise when including negative data in subsequent data analysis, and it is demonstrated that attempts to correlate erosion rates with hydro‐meteorological data in order to ascertain causes of erosion will be influenced by the way in which negative data are handled. It is thus suggested that any study of river bank erosion using erosion pins should state whether or not negative data were obtained, and if so, how they were included in data analysis. Failure to include this information could lead to comparison of mean erosion rates that reflect bank processes very differently.

The studies presented here offer a clear example of the value of ‘anomalous’ field data: results which do not appear to fit expected patterns can reveal as much about the processes in operation as those that do. Copyright © 2002 John Wiley & Sons, Ltd.
Unifying analysis of ergodic MIMO capacity in correlated Rayleigh fading environments
Authors: Kießling Mario
Published: January 2005

We present a novel mathematical approach that for the first time allows for calculating the moment generating function (MGF) of mutual information of Rayleigh fading MIMO channels with arbitrary fading correlation at transmitter and receiver. Specifically, we make use of certain hypergeometric functions of matrix argument, which are frequently used in multivariate statistics. This allows for a concise general expression for the MGF and we specialise the general result to scenarios with one‐side correlated and uncorrelated channels. Using the MGF, we derive exact formulas of the ergodic capacity, thus unifying the capacity analysis of correlated Rayleigh fading MIMO channels. It turns out that the ergodic capacity in all cases can be expressed in terms of a sum of determinants with elements that are a combination of polynomials, exponentials and the exponential integral E1 solely. The analysis is verified by Monte–Carlo simulations and shows a perfect match. Copyright © 2005 AEIT.