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1.
Forces such as technology change and increased competition provide opportunities and challenges that drive a firm to continuously evaluate and modify its resource capabilities. As a consequence, a firm's process change strategy is of paramount importance for sustained manufacturing success. However, fundamental elements of process change strategy are not well understood. Long term performance benefits associated with potential process change alternatives are often unclear. Moreover, uncertainty exists regarding the actual benefits that may be attained from various types of process change. Critical issues impacting the proper implementation of process change are frequently underestimated or largely ignored. Therefore, despite the improved performance sought, process change often leads to lower productivity, excessive equipment downtime, and deterioration in quality. As the authors review the relevant empirical and normative literature, a framework emerges that characterizes the salient features of a firm's process change strategy. The underlying dynamics of process change are explored and strategies are discussed to reduce the short-term disruption and enhance the long-term gain. In particular, the authors demonstrate the importance of creating and applying knowledge to improve the outcome of process change. They describe managerial actions that can be taken to reduce various sources of uncertainty associated with process change. Moreover, they identify key contributions as well as limitations of the existing normative literature on process change. Insights from the empirical literature are given that both support elements of the existing normative models and provide direction for future normative research. Thus, the authors seek to aid practicing managers and researchers alike to better understand the full scope and implications of process change.  相似文献   

2.
As software development migrates from its roots as a process for building a custom product to a process for building packaged products, there is a greater need for an appropriate product development process model that is market-oriented. Field data suggests that process models are not widely used in the package industry. An overview of normative process models in the software engineering, engineering management, and marketing disciplines reveals that all of them fall short in one way or another for packaged software processes. Eight special needs are identified that set the packaged software process model apart from other individual models: addressing multiple user types; differentiating the product; finding the remote customer; involving the remote customer; facilitating speed of development; creating the marketing interface; developing in a highly iterative mode; and releasing a near defect-free product. These needs are operationalized into the proposed packaged software process model. The process model is based on two central constructs: a requirements loop; and a quality loop. The loops are separated by a stage in which requirements specifications are frozen. The requirements loop's goal is to discover requirements early and comprehensively. It is incremental (relying on prototyping), has several evaluation and exit points, and structures involvement of customers and other external sources such as marketing. The quality loop addresses the need to reduce defects; it begins with design and coding stages. It is also incremental and has several evaluation and exit points  相似文献   

3.
The article unveils and discusses some of the internal and external forces that shape standardization. What would happen if it were solely up to the market to standardize? What are the motivations behind corporate activities in standards setting, which are, after all, costly and tend to be frustratingly slow? Why would users want to have standards? Answers to these questions are given, based on a critical literature review, combined with insights obtained from a survey. Finally, a proposal for a new standards setting process is made that takes all these issues into account  相似文献   

4.
The rapid advances in software defined radio (SDR) technologies over the past decade encouraged their transition from the lab to field deployment, and shifted the usage from disparate communication devices to the creation of large resilient wireless networks capable of adapting to highly variable environment conditions in a cognitive manner. Simulation models capable of accurately representing the behavior and properties of SDR devices operating in a networked environment thus become a prerequisite for both the evaluation of such networks as well as for providing a development platform for creating new cognitive capabilities. This paper describes our work in creating a network simulation model framework for software defined radios that takes into account some of the unique behaviors and requirements of SDRs not previously seen in purely hardware devices. Factors such as large and variable communication delays between software modules, contention to shared resources, such as CPU or memory, as well as continuous tuning and environment awareness functionality essential to SDR demand a different modeling approach as well as novel techniques that enable accurate scale testing.  相似文献   

5.
This paper presents a new spectral approach to color correction for medical image analysis applications. Linear estimation with regularization by a constrained principal eigenvector method is used for calibration of the camera system and estimation of the illumination spectrum while spectral surface reflectivities are determined by Wiener inverse estimation. Nonlinear devices are handled by piecewise linear interpolation and any linear color preprocessing inside the camera is explicitly modeled. All measurement and estimation processes are combined into a spectral calibration framework for practical application in computer-assisted image analysis. The novelty of our approach lies in the generalization of the image formation model allowing for linear preprocessing inside the camera system. Such transforms would lead to erroneous results with positivity constraint based algorithms or a monochromator based measurement. We provide experimental results from a comprehensive set of reference measurements acquired with a video endoscopy system for gastroscopic application.  相似文献   

6.
A heart-sounds gating device has been designed and tested which identifies, individually, both the first (S1) and second (S2) heart sound from their timing relationship, providing two trigger points through the cardiac cycle for synchronizing medical images. The new heart-sounds gate utilizes dynamically varying timing windows to anticipate the occurrence of S1 and S2. The heart-sounds gate has been initially applied to nuclear imaging of the cardiac bloodpool, but may be applied to any imaging modality requiring cardiac synchronization.  相似文献   

7.
8.
《信息技术》2015,(7):208-210
对于一个第三方测试团队而言,其针对关键性软件测试出相应的关键性问题的能力最能体现测试团队的核心价值。基于云计算环境下的测试知识库的建立,使得软件测试团队能够更加方便并且易于理解地进行经验的积累和优化。对云计算环境下第三方软件测试知识库研究的建立的必要性和技术构架加以相应的论述。  相似文献   

9.
A hierarchical framework which connects device and technology design parameters to specific circuit applications is presented. The functional circuit blocks which are used in the framework are defined. Examples of the use of this framework for design-intensive circuits are given, and experimental data which show the impact of device design on these circuit applications are presented. Technology-intensive circuit examples are also given which demonstrate the effect of technology enhancements on specific circuit applications  相似文献   

10.
The IEEE 802.11 protocol inherently provides the same long-term throughput to all the clients associated with a given access point (AP). In this paper, we first identify a clever, low-power jamming attack that can take advantage of this behavioral trait: the placement of a low-power jammer in a way that it affects a single legitimate client can cause starvation to all the other clients. In other words, the total throughput provided by the corresponding AP is drastically degraded. To fight against this attack, we design FIJI, a cross-layer anti-jamming system that detects such intelligent jammers and mitigates their impact on network performance. FIJI looks for anomalies in the AP load distribution to efficiently perform jammer detection. It then makes decisions with regards to optimally shaping the traffic such that: (a) the clients that are not explicitly jammed are shielded from experiencing starvation and, (b) the jammed clients receive the maximum possible throughput under the given conditions. We implement FIJI in real hardware; we evaluate its efficacy through experiments on two wireless testbeds, under different traffic scenarios, network densities and jammer locations. We perform experiments both indoors and outdoors, and we consider both WLAN and mesh deployments. Our measurements suggest that FIJI detects such jammers in real-time and alleviates their impact by allocating the available bandwidth in a fair and efficient way.  相似文献   

11.
We present an optimization framework for delay-tolerant data applications on mobile phones based on the Markov decision process (MDP). This process maximizes an application specific reward or utility metric, specified by the user, while still meeting a talk-time constraint, under limited resources such as battery life. This approach is novel for two reasons. First, it is user profile driven, which means that the user’s history is an input to help predict and reserve resources for future talk-time. It is also dynamic: an application will adapt its behavior to current phone conditions such as battery level or time before the next recharge period. We propose efficient techniques to solve the optimization problem based on dynamic programming and illustrate how it can be used to optimize realistic applications. We also present a heuristic based on the MDP framework that performs well and is highly scalable for multiple applications. This approach is demonstrated using two applications: Email and Twitter synchronization with different priorities. We present experimental results based on Google’s Android platform running on an Android Develepor Phone 1 (HTC Dream) mobile phone.  相似文献   

12.

Growth in multimedia traffic over the Internet increases congestion in the network architecture. Software-Defined Networking (SDN) is a novel paradigm that solves the congestion problem and allows the network to be dynamic, intelligent, and it centrally controls the network devices. SDN has many advantages in comparison to traditional networks, such as separation of forwarding and control plane from devices, global centralized control, management of network traffic. We design a policy-based framework to enhance the Quality of Service (QoS) of multimedia traffic flows in a potential SDN environment. We phrase a max-flow-min-cost routing problem to determine the routing paths and presented a heuristic method to route the traffic flows in the network in polynomial time. The framework monitors the QoS parameters of traffic flows and identifies policy violations due to link congestion in the network. The introduced approach dynamically implements policy rules to SDN switches upon detection of policy violations and reroutes the traffic flows. The results illustrate that the framework achieves a reduction in end-to-end delay, average jitter, and QoS violated flows by 24%, 37%, and 25%, respectively, as compared to the Delay Minimization method. Furthermore, the proposed approach has achieved better results when compared to SDN without policy-based framework and reduced end-to-end delay, average jitter, and QoS violated flows by 51%, 62%, and 28%, respectively.

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13.
本文报导一种带有抗流槽的介质加载波导辐射器的研制结果。这种辐射器有相对均匀的加热图形,泄漏辐射较其它波导辐射器小,能满足临床治疗需要。用小探针法测试了这种辐射器在模拟肌肉内近场分布,结果与用温度计测出的辐射器加热后的温度分布基本一致。实验还表明波导辐射器的抗流槽对宽边的泄漏辐射有明显抑制,但对窄边的泄漏抑制作用不很明显。  相似文献   

14.
以某型投放装置测试软件的设计为背景,考虑到多种测试仪的测试任务的共性与特点,提出了软硬件相结合的的通用化设计方法;描述了其流程化、自动化、层次化的测试方式;对其各部分功能和通用性进行详细介绍;经过测试和使用,该软件平台通用性能好,操作简单,其通用性对各类测试系统的设计和发展有着重要的意义。  相似文献   

15.
铜箔制程对CCL及PCB要求的应对   总被引:1,自引:0,他引:1  
PCB和CCL行业的高速发展,对作为其基础材料的铜箔提出了更多要求。铜箔必须同时满足PCB和CCL的多项性能要求,这给铜箔生产商带来了严峻的技术挑战和难得的发展机遇。从铜箔生产制成控制原理、方法和实际管控等方面,讨论铜箔如何应对CCL和PCB高度发展要求。  相似文献   

16.
The interest in methods that are able to efficiently compress microarray images is relatively new. This is not surprising, since the appearance and fast growth of the technology responsible for producing these images is also quite recent. In this paper, we present a set of compression results obtained with 49 publicly available images, using three image coding standards: lossless JPEG2000, JBIG, and JPEG-LS. We concluded that the compression technology behind JBIG seems to be the one that offers the best combination of compression efficiency and flexibility for microarray image compression.  相似文献   

17.
18.
A simulation model for use in the engineering design process is reported. The simulation model facilities reliability modeling by design engineers and reliability analysts early in the design process. The model applies to preliminary feasibility and design tradeoff studies. The authors describe the model, focus on applications to mission reliability analysis, and give a case study for the voice-communication system of the F-16 fighter aircraft  相似文献   

19.
An application of silicon micromachining to the analysis of blood cell rheology is described. The system, based upon a micromachined flow cell, provides a specific measurement of each cell in a statistically significant population in terms of both flow velocity profile and an index of cell volume while the cells flow through an array of microchannels. The rationale, design, and fabrication of the silicon micromachined flow cell is discussed. Interrelated considerations determining the design of the associated fluidic, mechanical, imaging, and real-time image analysis subsystems are examined. Sample data comparing normal and iron deficiency anaemic blood are presented to illustrate the potential of this technique  相似文献   

20.
Stringent cost and energy constraints impose the use of low-cost and low-power radio transceivers in large-scale wireless sensor networks (WSNs). This fact, together with the harsh characteristics of the physical environment, requires a rigorous WSN design. Mechanisms for WSN deployment and topology control, MAC and routing, resource and mobility management, greatly depend on reliable link quality estimators (LQEs). This paper describes the RadiaLE framework, which enables the experimental assessment, design and optimization of LQEs. RadiaLE comprises (i) the hardware components of the WSN testbed and (ii) a software tool for setting-up and controlling the experiments, automating link measurements gathering through packets-statistics collection, and analyzing the collected data, allowing for LQEs evaluation. We also propose a methodology that allows (i) to properly set different types of links and different types of traffic, (ii) to collect rich link measurements, and (iii) to validate LQEs using a holistic and unified approach. To demonstrate the validity and usefulness of RadiaLE, we present two case studies: the characterization of low-power links and a comparison between six representative LQEs. We also extend the second study for evaluating the accuracy of the TOSSIM 2 channel model.  相似文献   

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