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1.
To offer a theoretic guidance to practice, on the basis of the work in an emerging strand of supply chain management and by matching the constructs of performance and risk together, a framework between supply chain risk management and organizational performance is developed. The framework includes a series of mutually associated processes as follows: risk sources and profiles, risk and performance drives, risk and performance consequences, risk management responses, and risk and performance outcomes. Furthermore, every process is elaborated on in detail. Thereinto, organizational performance consists of efficiency and effectiveness which is linked to risk drivers and risk management responses. Finally, some necessary discussions and supplements are put forward from a practical point of view. This study is to some extent expected to be conducive to the theories and the practice of supply chain management for contemporary enterprises. 相似文献
2.
ZHOUShui－ying CHENRong－qiu 《上海大学学报(英文版)》2001,5(4):341-344
In order to satisfy the rapid changing requirements of customers,enterprises most cooperate with each other to form supply chain.The first and the most important stage in the forming of supply chain is the selection of participants.The article proposes a two-staged decision model to select partners.The first stage is the inter company comparison in each business process to select highefficiency candidate based on inside variables.The next stage is to analyse the combination of different candidates in order to select the most perfect partners according to a goal-programming model. 相似文献
3.
Traffic monitoring is of major importance for enforcing traffic management policies. To accomplish this task, the detection of vehicle can be achieved by exploiting image analysis techniques. In this paper, a solution is presented to obtain various traffic parameters through vehicular video detection system( VVDS). VVDS exploits the algorithm based on virtual loops to detect moving vehicle in real time. This algorithm uses the background differencing method, and vehicles can be detected through luminance difference of pixels between background image and current image. Furthermore a novel technology named as spatio-temporal image sequences analysis is applied to background differencing to improve detection accuracy. Then a hardware implementation of a digital signal processing (DSP) based board is described in detail and the board can simultaneously process fourchannel video from different cameras. The benefit of usage of DSP is that images of a roadway can be processed at frame rate due to DSP‘s high performance. In the end, VVDS is tested on realworld scenes and experiment results show that the system is both fast and robust to the surveillance of transportation. 相似文献
4.
Competing with successful products has become perplexing with several uncertainties and transmutes from time to time as customers＇ expectations are dynamic.That is why manufacturing firms exhaustively strive to look for a better competitive frontier using wellestablished and innovative product development（PD）processes.In this paper,we would like to answer three research questions：（i）What would be the effects of frontloading in PD？（ii）Can we improve our PD process endlessly？（iii）When is the critical time that the firm should take remedial action for improvements？As a contribution to the vast numbers of improvement methods in new product development（NPD）,this paper investigates the effects of front-loading using set-based concurrent engineering（SBCE）on cost and lead time.Models are developed and treated using a system dynamics（SD）approach.We assign a hypothetical upfront investment for SBCE and compare its effects on total cost and lead time of the development process.From the research,it is found that the total cost of PD is reduced almost by half-although the front loading is higher in order to encompass multiple design alternatives.The total product lead time is reduced by almost 20%.The model reveals the critical time for improvement of the PD process.We use SD tool（e.g.,STELLA）for simulation and visualization of the complex PD model,using SBCE as one of several strategies to frontload activities in the NPD process. 相似文献
5.
Biological early warning and emergency management support system for water pollution accident 总被引：1，自引：0，他引：1
Water pollution accidents such as chemical spill and toxicants leach have become a serious issue in the world, which brings great threats to the aquatic ecosystem and drinking water safety. To detect unknown pollutions in time and take proper emergency actions, this study developed a system which integrated an online intelligent water quality monitoring device with a high efficient water quality model. The device is based on water quality probes and biological sensors which use fish motion as indicator. The numerical model is a combination of Euler and Lagrangian approaches. Finite element method is applied to simulate the flow field in an unstructured grid, and the pollutant be- haviours are traced through particle tracking. Oracle is used to manage the basic and monitoring data, and ArcSDE as well as ArcIMS technologies are applied to make the system WebGIS-based so as to improve the data receiving and dispatching efficiency. The developed system has been successfully operated in Douhe Reservoir and Taihu Lake, China, where drinking water intakes are installed. It is seen from the applications that the online intelligent water qual- ity monitoring and emergency support system can be of great support to emergency management. 相似文献
6.
The current method to solve the problem of active suspension control for a vehicle is often dealt with a quarter-car or half-car model.But it is not enough to use this kind of model for practical applications.In this paper,based on considering the influence of factors such as,seat and passengers a MDOF(multi-degree-of-freedom)model describing the vehicle motion is set up.The MODF model,which is 8DOF of four independent suspensions and four wheel tracks,is more applicable by comparison of its analysis result with some conventional vehicle models.Therefore,it is more suitable to use the 8DOF full-car model than a conventional 4DOF half-car model in the active control design for car vibration.Based on the derived 8DOF odel,a controller is designed by using LQ(linear quadratic)control theory,and the appropriate control scheme is selected by testing various performance indexes.Computer simulation 8is carried out for a passenger car running on a road with step disturbance and random road disturbance expressed by Power Spectral Density(PSD).Vibrations corresponding to ride comfort are derived under the foregoing road disturbances.The response results for uncontrolled and controlled system are compared.The response of vehicle vibration is greatly suppressed and quickly damped.which testifies the effect of the active suspenson.The results achieved for various controllers are compared to invesigate the influence of different control schemes on the control effect. 相似文献
7.
A high-speed train-track coupling dynamic model is used to investigate the dynamic behavior of a high-speed train operating on a curved track with failed fasteners. The model considers a high-speed train consisting of eight vehicles coupled with a ballasted track. The vehicle is modeled as a multi-body system, and the rail is modeled with a Timoshenko beam resting on the discrete sleepers. The vehicle model considers the effect of the end connections of the neighboring vehicles on the dynamic behavior. The track model takes into account the lateral, vertical, and torsional deformations of the rails and the effect of the discrete sleeper support on the coupling dynamics of the vehicles and the track. The sleepers are assumed to move backward at a con- stant speed to simulate the vehicle running along the track at the same speed. The train model couples with the track model by using a Hertzian contact model for the wheel/rail normal force calculation, and the nonlinear creep theory by Shen et al. （1984） is used for wheel/rail tangent force calculation. In the analysis, a curved track of 7000-m radius with failed fasteners is selected, and the effects of train operational speed and the number of failed fasteners on the dynamic behaviors of the train and the track are investigated in detail. Furthermore, the wheel/rail forces and derailment coefficient and the wheelset loading reduction are analyzed when the high-speed train passes over the curved track with the different number of continuously failed fasteners at different operational speeds. Through the detailed numerical analysis, it is found that the high-speed train can operate normally on the curved track of 7000-m radius at the speeds of 200 km/h to 350 km/h. 相似文献
8.
On the basis of analyzing the system constitution of vehicle semi-active suspension,a 4-DOF(degree of freedom)dynamic model is established.A tunable fuzzy logic controller is designed by using without quantification method and taking into account the uncertainty,nonlinearity and complexity of parameters for a vehicle suspension system.Simulation to test the performance of this controller is performed under random excitations and definite disturbances of a C grade road,and the effects of time delay and changes of system parameters on the vehicle suspension system are researched.The numerical simulation shows that the performance of the designed tunable fuzzy logic controller is effective,stable and reliable. 相似文献
9.
Design of general multivariable process controllers is an attractive and practical alternative to optimizing design by evolutionary algorithms （EAs） since it can be formulated as an optimization problem. A closed-loop particle swarm optimization （CLPSO） algorithm is proposed by mapping PSO elements into the closed-loop system based on control theories. At each time step, a proportional integral （PI） controller is used to calculate an updated inertia weight for each particle in swarms from its last fitness. With this modification, limitations caused by a uniform inertia weight for the whole population are avoided, and the particles have enough diversity. After the effectiveness, efficiency and robustness are tested by benchmark functions, CLPSO is applied to design a multivariable proportional-integral-derivative （PID） controller for a solvent dehydration tower in a chemical plant and has improved its performances. 相似文献
10.
This paper presents a control strategy of a hybrid fuel cell/battery distributed generation （HDG） system in distribution systems. The overall structure of the HDG system is given, dynamic models for the solid oxide fuel cell （SOFC） power plant, battery bank and its power electronic interfacing are briefly described, and controller design methodologies for the power conditioning units and fuel cell to control the power flow from the hybrid power plant to the utility grid are presented. To distribute the power between the fuel cell power plant and the battery energy storage, a neuro-fuzzy controller has been developed. Also, for controlling the active and reactive power independently in distribution systems, the current control strategy based on two fuzzy logic controllers has been presented. A Matlab/Simulink simulation model is developed for the HDG system by combining the individual component models and their controllers. Simulation results show the overall system performance including load-following and power management of the HDG system. 相似文献
11.
The growth and evolution of the knowledge network in supply chain can be characterized by dynamic growth clustering and non-homogeneous degree distribution.The networks with the above characteristics are also known as scale-free networks.In this paper,the knowledge network model in supply chain is established,in which the preferential attachment mechanism based on the node strength is adopted to simulate the growth and evolution of the network.The nodes in the network have a certain preference in the choice of a knowledge partner.On the basis of the network model,the robustness of the three network models based on different preferential attachment strategies is investigated.The robustness is also referred to as tolerances when the nodes are subjected to random destruction and malicious damage.The simulation results of this study show that the improved network has higher connectivity and stability. 相似文献
12.
On urban arterials, travel time variability is largely dependent on the variability in the delays vehicles experience at signalized intersections. The interpretation of delay evolvement at intersections will give a comprehensive insight into arterial travel time variability and provide more possibilities for travel time estimation. Accordingly, an analytical model is proposed to study delay variability at isolated, fixed-time controlled intersections. Classic cumulative curves are utilized to derive average delay （per cycle） formulas by assuming a deterministic overflow queue. Then, an analogy with the Markov chain process is made to clarify the mechanism of stochastic delays and overflow queues at signalized intersections. It was found that, in undersaturated cases, the shape of the delay distribution changes very little over time, whereas for saturated and oversaturated cases the delay distribution is time-dependent and becomes flatter with an increasing number of cycles. The analysis of arrival distributions, e.g., Poisson and binomial, produces the conclusion that the variability of arrivals has a significant effect on delay estimates in both undersaturated and oversaturated conditions. A larger variance of arrival flow results in a larger variance of delay distribution. All of these analyses can help road authorities to gain insights into arterial travel time variability. 相似文献
13.
Ke-Sheng Wang 《上海大学学报(英文版)》2014,(2):106-120
In the wake of globalization,many modern manufacturing companies in Norway have come under intense pressure caused by increased competition,stricter government regulation,and customer demand for higher value at low cost in a short time.Manufacturing companies need traceability,which means a real-time view into thenproduction processes and operations.Radio frequency identification（RFID） technology enables manufacturing companies to gain instant traceability and visibility because it handles manufactured goods,materials and processes transparently.RFID has become an important driver in manufacturing and supply chain activities.However,there is still a challenge in effectively deploying RFID in manufacturing.This paper describes the importance for Norwegian manufacturing companies to implement RFID technology,and shows how the intelligent and integrated RFID（n-RFID） system,which has been developed in the Knowledge Discovery Laboratory of Norwegian University of Science and Technology,provides instant traceability and visibility into manufacturing processes.It supports the Norwegian manufacturing industries survive and thrive in global competition.The future research work will focus on the field of RFID data mining to support decision-making process in manufacturing. 相似文献
14.
15.
ZHUGE Yan CHUANG Shihwei 《天津大学学报(英文版)》2006,12(B09):171-176
The Australian love of ＂heritage＂ buildings （most of them are unreinforced masonry （URM） ） means that greater attention is required to secure their performance under seismic or impact loading in the future. A research project has been carried out to develop a new, economic and high strength retrofitting technique for masonry structures. A series of experimental testing on URM walls retrofitted with an innovative technique by cable system have been conducted. In this paper, an analytical model which is based on distinct element method（DEM） is developed to simulate the behaviour of retrofitted walls, in DEM, a solid is represented as an assembly of discrete blocks. Joints are modelled as interface between distinct bodies. It is a dynamic process and specially designed to model the behaviour of discontinuities. In order to assist the practising engineers to design this new retrofitted wall system, a simple mechanical model was also developed to predict the strength of the retrofitted walls. The results obtained from this simple mechanical model are compared with those from both experiments and distinct element model. 相似文献
16.
An integrated intelligent management is presented to help organizations manage many heterogeneous resources in their information system. A general architecture of management for information system reliability is proposed, and the architecture from two aspects, process model and hierarchical model, described. Data mining techniques are used in data analysis. A data analysis system applicable to real-time data analysis is developed by improved data mining on the critical processes. The framework of the integrated management for information system reliability based on real-time data mining is illustrated, and the development of integrated and intelligent management of information system discussed. 相似文献
17.
Forward and backward models for fault diagnosis based on parallel genetic algorithms 总被引：2，自引：0，他引：2
In this paper, a mathematical model consisting of forward and backward models is built on parallel genetic algorithms （PGAs） for fault diagnosis in a transmission power system. A new method to reduce the scale of fault sections is developed in the forward model and the message passing interface （MPI） approach is chosen to parallel the genetic algorithms by global single-population master-slave method （GPGAs）. The proposed approach is applied to a sample system consisting of 28 sections, 84 protective relays and 40 circuit breakers. Simulation results show that the new model based on GPGAs can achieve very fast computation in online applications of large-scale power systems. 相似文献
18.
in order to evaluate the seismic reliability of water distribution system and make rehabilitation decisions correspondingly, it is necessary to assess pipelines damage states and conduct functional analysis based on pipe leak- age model. When an earthquake occurred, the water distribution system kept serving with leakage. By adding a virtual node at the centre of the pipeline with leakage, an efficient approach to pressure-driven analysis was developed for simulating a variety of low relative scenarios, and a hydraulic leakage model was also built to perform hydraulic analy- sis of the water supply network with seismic damage. Then the mean-first-order-second-moment method was used to analyse the seismic serviceability of the water distribution system. According to the assessment analysis, pipes that were destroyed or in heavy leakage were isolated and repaired emergently, which improved the water supply capability of the network and would constitute the basis for enhancing seismic reliability of the system. The proposed approach to seismic reliability and rehabilitation decision analysis on water distribution system is demonstrated effective through a case study. 相似文献
19.
The Australian love of "heritage" buildings (most of them are unreinforced masonry (URM)) means that greater attention is required to secure their performance under seismic or impact loading in the future. A research project has been carried out to develop a new, economic and high strength retrofitting technique for masonry structures. A series of experimental testing on URM walls retrofitted with an innovative technique by cable system have been conducted. In this paper, an analytical model which is based on distinct element method (DEM) is developed to simulate the behaviour of retrofitted walls. In DEM, a solid is represented as an assembly of discrete blocks. Joints are modelled as interface between distinct bodies. It is a dynamic process and specially designed to model the behaviour of discontinuities. In order to assist the practising engineers to design this new retrofitted wall system, a simple mechanical model was also developed to predict the strength of the retrofitted walls. The results obtained from this simple mechanical model are compared with those from both experiments and distinct element model. 相似文献
20.
This paper describes the procedure of using the GM (1,1) weighted Markov chain (GMWMC) to forecast the utility water supply, a quantity that usually has significant temporal variability. The GMWMC is formulated into five steps: (1) use GM (1,1) to fit the trend of the data, and obtain the relative error of the fitted values; (2) divide the relative error into ‘state’ data based on pre-set intervals; (3) calibrate the weighted Markov chain model: herein the parameters are the pre-set interval and the step of transition matrix (TM); (4) by using auto-correlation coefficient as the weight, the Markov chain provides the prediction interval. Then the mid-value of the interval is selected as the relative error for the data. Upon combining the data and its relative error, the predicted magnitude in a specific time period is obtained; and, (5) validate the model. Commonly, static intervals are used in both model calibration and validation stages, usually causing large errors. Thus, a dynamic adjustment interval (DAI) is proposed for a better performance. The proposed procedure is described and demonstrated through a case study, which shows that the DAI can usually achieve a better performance than the static interval, and the best TM may exist for certain data. 相似文献