Understanding the Relationship and Interdependence of Concurrent Engineering and Computer-Integrated Manufacturing: A Perspective from the Defense Community

ABSTRACT

What is concurrent engineering (CE)? What is computer-integrated manufacturing (CIM)? What are the important aspects of each? Many people have attempted to answer these questions, but few have analyzed the relationship and interdependence of the two concepts. The philosophical foundations of CE and CIM are interrelated and have many common elements that are critical to successful implementation. A thorough understanding of both concepts is required to maximize their benefits. This article explores each concept and then evaluates their interrelationships. It concludes with a discussion of the implementation of both concepts within the defense environment.     

Development of an assessment framework for green highway construction

Abstract

The objective of this research is to develop a framework for the assessment of green highway projects. Highway construction is chosen from among the various types of large‐scale infrastructure because they cover broad areas and take up a large share of a nation's infrastructure development. After completing a literature review we employ the Max‐Min Fuzzy Delphi method to identify the major categories and their corresponding items most suitable for assessing the “greenness” of a highway project. The five major categories identified are: preservation of the eco‐system, plantations to reduce CO₂ emission, preservation of material resources, waste reduction, and water conservation. The Analytical Hierarchy Process (AHP) is then employed to determine the weighting of the major categories as well as the sub items in each category. The end result is an assessment rating framework to assess the “greenness” of a highway construction project.     

Realization of a Conditional Unitary Process by Systems of Collett and Knight

Abstract

This paper presents a physical interpretation of a conditional unitary process discussed in recent articles by one of the authors. It is verified that a generation process of a coherent squeezed state with arbitrary amplitude always corresponds to the conditional unitary process. Some examples of a quasi-free system are given.     

Spatial resolution implications of digitizing aerial photography for environmental applications

Abstract

Accuracy, flexibility and cost effectiveness are advantages of using digitized aerial photographs as a data source for remote sensing studies of the environment, such as forests. However, the relationship between the resolution of digital images and the aerial photographs from which they were derived must be addressed to ensure valid application using the environmental data. This communication considers issues that affect the information content of environmental data through the spatial resolution of photographs and digitized images, and suggests how users can optimize the spatial resolution of the latter by selecting an appropriate scanning aperture. An optimal scanning aperture can be chosen by considering the combination of the resolving power of the camera system, the scale of the original photograph and the desired pixel size of the digital image. Optimizing spatial resolution while scanning will maximize the spatial information obtained from the original photographs without generating unnecessarily large file sizes. The authors make several recommendations for the digitization of aerial photographs for environmental applications, such as analyses of forests.     

Valuation for the Strategic Management of Research and Development Projects: The Deferral Option

Abstract:

The most widely used financial technique for evaluating projects is discounted cash flow; however, discounted cash flow analysis fails to consider flexibility. Real options analysis offers an alternative technique that provides value for the managerial flexibility that is inherent in most R&D projects. This article investigates the deferral option using computer simulation. There are five variables that determine the value of the deferral option, and simulations analyze these variables over a wide range of conditions. Sensitivity analysis on the five variables is performed and the results are discussed.     

Optimal investment strategies for flexible workers under uncertain demand

Abstract

Skill chaining (SC) has proven to be an effective way to balance the workload and elevate the capacity of a serial production line. However, SC training is costly. Therefore, the costs and benefits of investment in cross-training must be weighed. To save costs, we propose a partial skill chaining (PSC) strategy to save cross-training investment costs in an assemble-to-order (ATO) system. First, we build a chain segment model to describe the PSC. Then, we provide a heuristic algorithm with which to determine the optimal path for cross-training. We also examine the efficiency of several training schemes from the perspective of flexibility structure. Second, we find that the costs of both overproduction and delivery delay in an ATO system with uncertain demand can be reduced after obtaining the capacity. The problem is then transformed into a trade-off between investments and benefits. Finally, we identify the relevant decision-making criteria for both flexibility capacity maximization and profit maximization.     

Amplitude matching strategy for wave-optical design of monofunctional systems

Abstract

The design of optical systems capable of transforming one given input field into an output field which maximizes one prescribed merit function is discussed in the functional embodiment of the system, that is by dealing with transmission functions instead of structured matter. Customary beam shaping techniques are identified as a special case of a more general strategy which is called amplitude matching. This strategy makes use of the field quantities amplitude and phase and therefore it is a wave-optical design approach. The flexibility of the technique is demonstrated by various examples. Parameters like conversion efficiency, signal-to-noise ratio, distances between transmission functions, and the number of transmission functions necessary for the implementation of wave transformations are discussed.     

Improved Systems Understanding by Similarities and Analogies

ABSTRACT

A set of definitions of systems engineering concepts is the point of departure of this article. Those definitions are generic and cover the system and its life cycle, the systems engineering discipline, and the systems engineering process. A systems engineer must be able to analyze and understand systems first on a conceptual level independent of technology, that is, a technology-free functional analysis. More detailed knowledge and deeper insight into a concrete technology are required later. The systems engineer must be able to move from one system project to another, sometimes with entirely different technologies and requirements. This article points to a need for greater flexibility and easier adaptability on the part of the systems engineer. This need implies that the knowledge base and professional toolbox for the systems engineer must meet this requirement also. A way this requirement can be met is by system similarity and the principle of analogy between functional characteristics of systems.     

Morphological comparison of isotactic polypropylene molded by water-assisted and conventional injection molding

It is well known that water-assisted injection molding (WAIM) process can be fulfilled based on the melt filling stage of conventional injection molding (CIM) process. However, due to the different physical fields involved during WAIM and CIM processes, WAIM part should exhibit unique morphological features compared with the CIM one. In this study, isotactic polypropylene (iPP) parts were prepared by WAIM and CIM, respectively, and their comparative study on morphology were therefore carried out by means of polarized optical microscopy (POM) and two-dimensional (2D) wide-angle X-ray diffraction (WAXD). POM observations illustrated that the WAIM part exhibits a “skin–core–water channel” structure, while the CIM part shows a typical “skin–core” structure. 2D-WAXD results showed obvious arclike reflections in each position along thickness direction of the WAIM part, indicating a pronounced molecular orientation. Furthermore, a parent–daughter model (or branched shish-kebab structure) appears at 0 and 100 μm for both the parts, and the fraction of daughter lamellae for WAIM part is lower than that of CIM part. As for the 1D-WAXD curves, it is noticed that there is a very tiny (300) reflection of β-form in the CIM part, while it is invisible in all positions of the WAIM part. In addition, the crystallinity and crystalline size L of CIM part are found to be higher than that of WAIM part. Those results demonstrate that water penetration and rapid cooling rate have a significant effect on the morphological features of WAIM part.     

A categorizing mechanism using signature file to construct multidimensional data into a concept hierarchy tree for enhancing data warehouse access

Abstract

A large number of government or business organizations have found that data warehouse systems are valuable tools in today's competitive, fast‐evolving world. However, the databases in data warehousing systems usually obtain data from thousands of various categories, which means it is not easy to quickly find all the data items queried because they are so widely scattered. In real‐life applications, whether the new data to be incorporated into the data warehousing system are legal or not is another important thing to be taken into account. Now, how to overcome the two obstacles above in an efficient way is the major problem we have to solve before a real powerful data warehousing system will be constructed.

In this research, the technique of signature file is utilized to build up an automatic data classifying mechanism upon multi‐dimensional correlation forms in database. In addition, the paper also introduces the concept of a hierarchy tree to organize all the data categories for the convenience of inspection when data are to be stored or accessed. Through such construction procedures, the proposed method does not only effectively manage to incorporate all the newly found data items into the data warehouse system to achieve data storage legally, it also enhances the data accessing efficiency.     

Design Patent Map: An Innovative Measure for Corporative Design Strategies

Abstract:

The design patent map is one of the essential strategic measures for formulating design strategies. Because the design patent is considered less definite than other patent categories, it is relatively difficult to create a design patent map. No study has been discovered in a worldwide search of patent documents or publications that is relevant to design patent maps, proving the innovative nature of this study. The authors have extracted 96 representative works for bicycle frame design patents that were published from 1992 to 2003 and have used them as the study samples. To ensure precise interpretation of the technical data of bicycle frames and to create the design patent map, the authors have interviewed 11 design patent examiners who have an average of 10 years of experience in patent examination, and are currently working in the Taiwan Intellectual Property Office. Based on the matrix for the available patenting capability and the degree of need for patents, the authors have further converted the design patent map into nine feasibly specific design strategies: (1) overall seizure, (2) expansion, (3) closing-in, (4) envelopment, (5) dispersion, (6) pincer attack, (7) division, (8) deviation, and (9) abandonment. As a result, enterprises will be able to employ the design patent map developed in this study to customize their own design strategies. Such a strategic measure will soon become a new competitive edge for enterprises with the arrival of the knowledge economy era.     

CIM系统设计中的关键问题

虽然新的制造系统不断涌现,企业仍然对ＣＩＭ给予很大广泛的认可。本文讨论了ＣＩＭ设计中的一些关键问题。首先,根据业务过程重组来实施ＣＩＭ至关重要,其次,必须采用ＣＩＭ的功能体系少容纳各种功能系统,以便更好地执行业务流过程,同时,需要有相应的集成为支持整个企业的数据管理。     

An efficient and flexible bit‐level systolic array for inner product computation and its application to fir filtering

Abstract

In this paper, a bit‐level systolic array with bit‐serial arithmetic is proposed for inner product computation. If data vectors are entered continuously and interleavedly, the proposed inner product array can be fully utilized for one of two operating modes: 1) computing two independent inner products concurrently; 2) computing the sum of two inner products or an inner product with a double size. For a given data word length B, the system yields two outputs every 2B cycles for mode 1 (i.e., the average throughput is one per B cycles), and one output every 2B cycles for mode 2. As compared to existing related arrays, the proposed one has a little increase in hardware complexity, but is more flexible for use in applications. FIR filters based on the inner product array are given for demonstration of the flexibility.     

Anthropomorphic motion control of a gantry robot in assembly cells

Abstract

The demand for flexible production systems in which the flexibility at assembly processes is increased by new forms of human-robot collaboration rises. Besides occupational safety the transparency of the robot’s actions and the mental effort are of special importance. Based on the fact that anthropomorphic features of a robotic system can improve its acceptance, anthropomorphic movements of a gantry robot in an assembly cell are compared to conventional point-to-point movements. Results of a study with 20 male participants, in which the influence of these movements of the gantry robot on mental effort, prediction time and prediction accuracy was investigated, are presented in this paper. Results show that the participants could predict the target position of the presented movement significantly faster and more accurately when the gantry robot was controlled by the anthropomorphic motion primitives (α?=?0.05). The mental effort ratings show in general reduced values for the anthropomorphic movement, but this effect is statistically not significant.     

Deadlock avoidance algorithm for flexible manufacturing systems by calculating effective free space of circuits†

Modern flexible manufacturing systems (FMS) are highly automated and flexible in which raw parts of various types are processed concurrently. Deadlock issue arises easily in these systems due to shared equipment usage and high production flexibility. It was indicated in Wysk et al . (Wysk, R., Yang, N. and Joshi, S., Detection of deadlocks in flexible manufacturing cells. IEEE Trans. Rob. Auto., 1991, 7, 853–859.) that when a manufacturing system is modelled by a digraph, existence of circuits in such a graph is a necessary condition for deadlock. Deadlock avoidance for systems with free choice in part routing has been well studied in the Petri net formalism, however, we have not found that it has been studied systematically in the digraph formalism. Because of choices introduced, part flow dynamics become much more complex. Based on our previous work Zhang et al . (Zhang, W., Judd, R.P. and Paul P., Evaluating order of circuits for deadlock avoidance in a flexible manufacturing system. Int. J. Prod. Res., 2006, 44, 5247–5259.), this paper presents a deadlock avoidance algorithm for FMS, which allows free choices in part routing by calculation of effective free space of circuits of the digraph model. The algorithm is highly permissive since the effective free space calculation captures more parts flow dynamics, especially when there exist multiple knots in the digraph model. And it runs in polynomial time once the set of circuits of the digraph is computed offline. Simulation results on selected examples are given.     

THE EFFECT OF DAMAGE GROWTH ON THE AEROELASTIC RESPONSE OF COMPOSITE STRUCTURES

SUMMARY

The investigators present a study of the aeroelastic response of composite structures which are subject to damage. Herein, the damage is the result of the natural progression of microcracks in the laminate structure. The aeroelastic stability boundary is shown to evolve over time as a consequence of the damage. The dynamic characteristics are inherent to the coupled damage/aeroelastic system and are developed as part of the solution methodology. The authors establish the importance of the intrinsic dependence of aeroelastic stability and damage. Aeroelastic response is shown to be highly dependent upon the distribution and accumulation of damage which itself is dependent upon the presence of the unsteady aerodynamic loads.     

Permanent 3D microstructures in a polymeric host created using holographic optical tweezers

Abstract

Permanent 3D microstructures are created within a gel using holographic optical tweezers. The micron-sized particles are arranged in a precise geometry within an appropriate liquid, and become fixed in position upon polymerisation of the surrounding media. The flexibility of the holographic approach enables any structural arrangement to be produced, dependent upon application. We demonstrate the technique by creating structures within a biocompatible host, enabling future applications in biotechnology.     

A high reliability two‐level fault tolerant mesh design and applications

Abstract

This paper presents a novel technique for the enhancement of the operational reliability of processor arrays by a multi‐level fault‐tolerant design approach. The proposed fault tolerant architecture uses a flexible reconfiguration of redundant nodes, thereby offering a better spare utilization than existing two‐level redundancy schemes. The spare nodes at each level can replace any of the failed primary nodes, not only at the same level but also those at the lower levels. The architecture can be adopted to increase the system reliability in Multi Chip Modules (MCMs). The main contributions of our work are the higher degree of fault tolerance, higher overall reliability, higher flexibility, and a better spare utilization.     

Adaptive robust control for seismically excited structures: The Chi‐Chi earthquake

Abstract

This paper proposes control for a seismically excited N story building. Intrinsic properties of the building's own robustness are analyzed by using an input‐to‐state stability method and solving a linear matrix inequality. Then frequency analysis on the base isolation gives guidelines for choosing parameters and also reveals the narrow flexibility of the base parameters. This frequency analysis, on the other hand, shows the need for a hybrid controller. Therefore a passive baseisolated building model is considered with an active hydraulic actuator. This passive and active combined hybrid controller is then designed using the backsteppping approach. The parametric uncertainties of both the building and the actuator are considered. Therefore an adaptive backstepping controller is designed. An H⁸ criterion is given to attenuate the effects of seismic excitation. Numerical simulations are carried out using the Chi‐Chi earthquake of Taiwan as an excitation source on a twelve story building. Results show that the hybrid system design is valid, with reasonable control force.