Showing papers by "Stevens Institute of Technology published in 1998"

Morphological Development in Solvent-Cast Polystyrene−Polybutadiene−Polystyrene (SBS) Triblock Copolymer Thin Films

Abstract: This paper describes morphological development in solvent-cast polystyrene (PS)−polybutadiene (PB)−polystyrene (SBS) triblock copolymer thin films (30 wt % PS) as a function of solvent evaporation ...

Performance analysis of minimum variance CDMA receivers

Abstract: Constrained optimization of the receiver's output variance has previously been proposed as a relatively simple method for designing blind multiuser detectors for DS-CDMA systems. A single constraint is sufficient for the AWGN case, whereas multiple constraints should be used in a multipath environment. It is shown in this paper that the choice of the constraint parameters in the multipath case can have a significant effect on the system performance. A max/min approach for optimizing the constraint is proposed, resulting in blind solutions with improved performance. It is shown that the performance of the proposed method tends to be close to that of the MMSE receiver at high SNR, whereas the constraint parameters converge to the multipath channel parameters. The proposed method does not require knowledge of the interfering users' codes and timing. Simulation results support those performance claims.

Sensitive absorption spectroscopy with a room-temperature distributed-feedback quantum-cascade laser

Abstract: We report what we believe are the first spectroscopic measurements to be made with a room-temperature quantum-cascade distributed-feedback laser. Using wavelength modulation spectroscopy, we detected N2O and CH4 in the chemical fingerprint wavelength range near 8 µm. The noise equivalent absorbance for our measurement was 5 parts in 105, limited by excess amplitude modulation on the laser output, which corresponds to a 1-Hz bandwidth detection limit of 250 parts N2O in 109 parts N2 in a 1-m path length.

From theory to practice: toward a typology of project-management styles

Abstract: Research literature on the management of projects has been quite slow in its conceptual development and still suffers from a scanty theoretical basis. One of the main impediments in the study of projects has been the absence of constructs and the little distinction that has been made between the project type and its managerial and organizational style. Based on the findings in a field study of 26 case projects, this research shows that there is a need to adopt a more project-specific contingency approach to project management in organizations. This study explores a two-dimensional theoretical model for the classification of technical (or engineering) projects. Projects are classified according to four levels of technological uncertainty at the time of project initiation and three levels of system scope, which is their location on a hierarchical ladder of systems and subsystems. Considerable differences were found in management style, project organization and operational practice when moving along each of the model's two axes. Differences also were observed in simultaneous change in both dimensions. The findings suggest a handful of practical and managerial implications. They are based on the premise that a proper project classification prior to project initiation and a carefully selected management style may lead to better implementation and to an increased chance of project success.

Innovation Strategies Under Uncertainty: A Contingency Approach for New Product Development

Abstract: Innovation is especially critical, yet risky, in dynamic, uncertain markets where the product or service employs new and uncertain technologies. Under these conditions, the new product professional should rely on a variety of tools and techniques to assist him or her to innovate more effectively with a greater probability of succeeding. The new product development literature offers several tools to help. These tools are based on one of six innovation strategies: process, speed, learning, market, technology, and quantitative. However, it is not clear which strategy should be used and when. This article examines these dominant innovation strategies and evaluates their applicability in the environment of emerging markets with emerging technologies. We have found that for the more extreme forms of innovation, a learning-based strategy will improve the chances of success.

New Product Team Learning: Developing and Profiting from Your Knowledge Capital

Abstract: Continuous improvement has been credited with helping companies in decreasing manufacturing costs, reducing inventory, compressing cycle time, improving quality, speeding distribution, and increasing customer satisfaction. But what is at the heart of continuous improvement? What allows a company to get better over time? Learning -- or more accurately, organizational learning. How effectively an organization learns can dictate whether it will improve, and how fast, or if it is destined to lose ground to competitors who can and do learn.Nowhere is organizational learning more critical than in new product development -- where one technological platform can lead to families of products, and learning must be transferred from one team to the next. Some companies excel at transporting knowledge between teams and then capitalizing on it, while others do not. Motorola built on its portable pager business to develop portable cellular telephones, Searle built on its technical core competency in drug research to develop NutraSweet, and Corning used its expertise in glass technology to develop optical fibers.1 Xerox, however, failed to apply its copier technology to the personal copier market until competitors were firmly entrenched, Firestone and Goodyear resisted the shift to radial tires, and Seagate waited to develop 3.5" computer disk-drives until other companies had secured an insurmountable lead.Why are some companies able to build competitive advantages by using their storehouse oforganizational knowledge while others are not? What programs can companies institute that wouldenable them to create and profit from the knowledge that they have labored to acquire? How canorganizations establish policies enabling their new product teams to draw on the firm's knowledge base augment it, and then develop the kind of technological breakthroughs that create entirely new industries?By studying a progression of new product projects that included the Apple II, IIe, III, Lisa, Mac and Mac ; the Hewlett Packard 85, 125, 150 and Vectra; and the IBM DataMaster, PC and PCjr., we learned how teams learn.3 The insights came after completing a total of 85 3/4 hours of interviews (80 hours on tape) with 70 team members: 19 IBM team members; 25 HP team members; and 26 Apple team members. Interviewees included senior company executives such as Apple's co-founder, Steve Wozniak; HP's Executive Vice President, Dick Hackborn; HP's Personal Computer Office Division General Manger, Bob Puette; and IBM's initial PC project leader, Bill Lowe in addition to managers and individual team members in manufacturing, marketing, planning and engineering (hardware, software and firmware).

Vibro-Acoustic Modulation Nondestructive Evaluation Technique:

Abstract: Nonlinear acoustic technique has been recently introduced as a new tool for nondestructive inspection and evaluation of fatigued, defective, and fractured materials. Various defects such as cracks, debonding, fatigue, etc. lead to anomalous high levels of nonlinearity as compared with flawless structures. One of the acoustic manifestations of such nonlinearity is the modulation of ultrasound by low frequency vibration. Two methods employing the nonlinear interaction of ultrasound and vibration were developed, namely vibromodulation (VM) and impactmodulation (IM) methods. VM method employs forced harmonic vibration of a structure tested, while IM method uses impact excitation of structure natural modes of vibration. The feasibility tests were carried out for different objects and demonstrated high sensitivity of the methods for detection of cracks in steel pipes and pins, bonding quality in titanium and thermoplastic plates used for airspace applications, cracks in combustion engine, adhesion flaws in bond...

Transparent non-disruptable atm network

Abstract: A method and apparatus for the transparent, non-disruptable transfer of data, particularly multimedia data, through any packet-based network, such as an ATM network is provided. The method of the present invention includes the step of setting a primary path and a secondary path between nodes of a network, or of a network domain. Accordingly, when a switch or node establishes a Virtual Path (VP) to another switch with specified effective bandwith, it also has an alternate VP that is available, although no bandwidth is actually used. The method of the present invention further includes the step of optimizing the available capacity of the system through management actions. For handling congestion and resource failures, the total effective bandwidth on each physical link is categorized in terms of idle capacity (unused or available), used capacity (for existing VPs), and spare capacity. When a resource failure occurs, the idle capacity is used for real-time switching of the VP and service is not disrupted. This is accomplished by an alarm indication management cell which is delivered when a resource problem is encountered. This management cell sets forth the secondary path and the bandwidth associated therewith. On the other hand, if idle capacity does not exist, the spare capacity is used, while the bandwidth for all other VPs is reconfigured using virtual bandwidth optimization. Therefore, service disruption does not occur. In a wireless, mobile network, the present invention monitors node movement and takes management actions on the basis of such node movement to prevent service disruption.

Evaluation of Workflow Management Systems - A Meta Model Approach

Abstract: The automated enactment of processes through the use of workflow management systems enables the outsouring of the control flow from application systems. By now a large number of systems, that follow different workflow paradigms, are available. This leads to the problem of selecting the appropriate workflow management system for a given situation. In this paper we outline the benefits of a meta model approach for the evaluation and comparison of different workflow management systems. After a general introduction on the topic of meta modeling the meta models of the workflow management systems WorkParty (Siemens Nixdorf) and FlowMark (IBM) are compared as an example. These product-specific meta models can be generalized to meta reference models, which helps to specify a workflow methodology. Exemplary, an organizational reference meta model is presented, which helps users in specifying their requirements for a workflow management system.

Vibro-acoustic modulation nondestructive evaluation technique

Abstract: Nonlinear acoustic technique has been recently introduced as a new tool for nondestructive inspection and evaluation of fatigued, defective, and fractured materials. Various defects such as cracks, debonding, fatigue, etc. lead to anomalous high level of nonlinearity as compared with flawless structures. One of the acoustic manifestations of such nonlinearity is the modulation of ultrasound by low frequency vibration. Two methods employing the nonlinear interaction of ultrasound and vibration were developed, namely vibro-modulation (VM) and impact-modulation (IM) methods. VM method employs forced harmonic vibration of a structure tested, while IM method uses impact excitation of structure natural modes of vibration. The feasibility tests were carried out for different objects and demonstrated high sensitivity of the methods for detection of cracks in steel pipes and pins, bonding quality in titanium and thermoplastic plates used for airspace applications, cracks in combustion engine, adhesion flaws in bonded composite structures, and cracks and corrosion in reinforced concrete. The model of the crack allowing to describe the modulation of sound by vibration is discussed. The developed nonlinear technique demonstrated certain advantages as compared with the conventional linear acoustic technique, specifically discrimination capabilities, sensitivity, and applicability to highly inhomogeneous structures.

Agents on the move [mobile software agents]

Abstract: The author describes a new kind of software, based on artificial intelligence research, that can move itself from place to place to help people work more effectively. Known as agents, these artificial assistants are software components that live inside computer environments. Developed out of research in artificial intelligence (AI), agents were made in a variety of forms to perform all sorts of useful work-including obtaining airline departure dates and times, filtering e-mail for messages the user considers important, alerting users to significant stock price changes, and a host of other tasks. At first, agents were constrained to a single computer or at most to a single computing environment-a closed, homogenous network of, say, Unix platforms. Their behavior was limited and all the tasks they could do had to be pre-established. Today, agents are breaking the bonds that confine them to a single environment while learning new ways of accomplishing tasks on their own, based on their experience. The newcomers are called mobile agents, because they can move from one computer to another. As they emerge from the shadow of AI research, they are bringing together telecommunications, software, and distributed-system technologies to create new ways of getting things done.

Lyapunov stability of two-dimensional digital filters with overflow nonlinearities

Abstract: In this paper, the second method of Lyapunov is utilized to establish sufficient conditions for the global asymptotic stability of the trivial solution of zero-input two-dimensional (2-D) Fornasini-Marchesini state-space digital filters which are endowed with a general class of overflow nonlinearities. Results for the global asymptotic stability of the null solution of the 2-D Fornasini-Marchesini second model with overflow nonlinearities are established. Several classes of Lyapunov functions are used in establishing the present results, including vector norms and the quadratic form. When the quadratic form Lyapunov functions are considered, the present results involve necessary and sufficient conditions under which positive definite matrices can be used to generate Lyapunov functions for 2-D digital filters with overflow nonlinearities.

Learning Is the Critical Success Factor in Developing Truly New Products

Abstract: Successful new product development is tough, especially for truly new products. How can a company successfully develop and commercialize such products? An examination of four radically new innovati...

Melting phenomena and mechanisms in polymer processing equipment

Abstract: This article examines the heating and melting phenomena taking place when individual polymer particulates or compacted polymer particulate systems are subjected to stressing that forces them to deform and flow. The heating/melting behavior in compression experiments of single polymer cylinders and melting in batch internal mixers, as well as in corotating twin-screw extruders, was examined. Different polymers and different polymer particulate solid systems were used, over a range of processing conditions. The results of this work shed light on the important roles that solid dissipative deformation and interparticle frictional phenomena play in generating the heat necessary to melt polymer particulate systems. Also, an attempt is made to deal with the modification of the thermal energy balance equation, so that it includes the heat-generating dissipative source terms. © 1998 John Wiley & Sons, Inc. Adv Polym Techn 17: 285–305, 1998

Method and apparatus for acoustic detection of mines and other buried man-made objects

Abstract: A device (10) which employs an acoustic signal having one or more frequencies for penetrating into ground, water, or sediments and vibrating a compliant buried object (8) is provided. When these acoustic signals encounter an acoustically compliant object (8) such as a mine, the acoustic signals vibrate the compliant object (8), leading to a vibration of the compliant object (8) against the boundaries of the surrounding medium such as ground sediment, creating a nonlinear distortion of the probing signal including the generation of harmonics and acoustic waves with combination frequencies (nonlinear signals). These nonlinear vibrating signals are received from the surface by a sensor (20). The amplitude of the measured nonlinear signals indicates the presence of an acoustically compliant object (8) such as a mine. The present invention also relates to a method and apparatus which emits an electromagnetic RF probing signal and acoustic or vibration signal (modulating signal), detects the reflected electromagnetic signal from the buried object (8), and processes the received signal, identifying the modulation caused by vibration.

Squeezing Flow of Viscoplastic Fluids Subject to Wall Slip

Abstract: Polymer processing operations such as compression molding, sheet forming and injection molding can be modeled by squeezing flows between two approaching parallel surfaces in relative motion. Squeezing flows also find applications in the modeling of lubrication systems, and in the determination of rheological properties. Here, analytical solutions are developed for the constant-speed squeezing flow of viscoplastic fluids. It is assumed that the fluid is purely viscous, and hence viscoelastic effects unimportant. The rheological behavior of the viscoplastic fluids is represented by the Herschel-Bulkley viscosity function. The deformation behavior of commonly encountered viscoplastic fluids is generally complicated by the presence of wall slip at solid walls, which is a function of the wall shear stress. The slip coefficient that relates the slip velocity to the shear stress is affected by the material of construction and also the roughness of the solid surfaces, leading to the possibility of different slip coefficients at various solid surfaces. The model developed in this study accommodates the use of different slip coefficients at different solid surfaces. The accuracy of the solutions is established, and the effects of various parameters such as slip coefficient and apparent yield stress are examined. The solutions provide useful design expressions that can be utilized for squeezing flows of viscoplastic fluids, with or without wall slip at the solid boundaries.

Self-monitoring and 360-degree ratings.

Abstract: We examined the relationship between self-monitoring (SM) and supervisor, assessor, peer, and subordinate ratings for 191 managers who participated in a developmental assessment center. We collected self-ratings from the managers concerning their ability and motivation to engage in self-monitoring. SM ability was positively related to supervisor and assessor ratings of interpersonal effectiveness (e.g., empowerment, managing teams, influencing others) but was unrelated to supervisor and assessor ratings of business competence (e.g., planning, decision making, strategic thinking, business knowledge). In contrast, SM motivation was negatively related to peer ratings of business competence. Still, SM explained relatively little variance in 360-degree ratings. 360-degree ratings do not appear to be contaminated by the target manager's SM; the small but significant relationship between SM ability and ratings appears to be job-related (and therefore desirable).

Electron impact ionization of the SF5 and SF3 free radicals

Abstract: We measured absolute cross sections for the electron-impact ionization and dissociative ionization of the SF5 and SF3 free radicals from threshold to 200 eV using the fast-neutral-beam technique The total single ionization cross sections at 70 eV were found to be 51×10−16 cm2 (SF5) and 32×10−16 cm2 (SF3) The cross sections reach their maximum at about 100 eV for both radicals, with values of 54×10−16 cm2 (SF5) and 35×10−16 cm2 (SF3) Dissociative ionization is important only for SF5, where the SF5+ parent ionization cross section and the SF4+ fragment ionization cross sections have roughly the same value By contrast, the ionization of SF3 is dominated by the formation of SF3+ parent ions A comparison of the measured total single ionization cross sections with calculated cross sections, using a modified additivity rule, shows excellent agreement for both radicals in terms of the absolute cross section values and the cross section shapes Total single ionization cross sections were also calculated f

Complex Aggregation at Multiple Granularities

Abstract: Datacube queries compute simple aggregates at multiple granularities. In this paper we examine the more general and useful problem of computing a complex subquery involving multiple dependent aggregates at multiple granularities. We call such queries “multi-feature cubes.” An example is “Broken down by all combinations of month and customer, find the fraction of the total sales in 1996 of a particular item due to suppliers supplying within 10% of the minimum price (within the group), showing all subtotals across each dimension.” We classify multi-feature cubes based on the extent to which fine granularity results can be used to compute coarse granularity results; this classification includes distributive, algebraic and holistic multi-feature cubes. We provide syntactic sufficient conditions to determine when a multi-feature cube is either distributive or algebraic. This distinction is important because, as we show, existing datacube evaluation algorithms can be used to compute multi-feature cubes that are distributive or algebraic, without any increase in I/O complexity. We evaluate the CPU performance of computing multi-feature cubes using the datacube evaluation algorithm of Ross and Srivastava. Using a variety of synthetic, benchmark and real-world data sets, we demonstrate that the CPU cost of evaluating distributive multi-feature cubes is comparable to that of evaluating simple datacubes. We also show that a variety of holistic multi-feature cubes can be evaluated with a manageable overhead compared to the distributive case.

Pathways for Knowledge: How Companies Learn Through People

Abstract: Many reports state that an organization may be more successful if the company exhibits a high level of learning. Learning and storage of the knowledge gained is of great importance to this end. Where do the people within RD 2) more than half of all company knowledge transmission flows verbally and informally through ad hoc channels, giving evidence that the communication means has changed greatly over t...

Idea Generation: Who Has The Most Profitable Ideas

Abstract: Idea generation has been recognized as an important part of the front end of the innovation process. Few studies have empirically examined where the most profitable ideas come from or the linkages ...

Measurement of Polystyrene Mean Inner Potential by Transmission Electron Holography of Latex Spheres

Abstract: This study describes the use of transmission electron holography to determine the mean inner potential of polystyrene. Spherical nanoparticles of amorphous polystyrene are studied so that the effect of specimen thickness on the phase shift of an incident electron wave can be separated from the intrinsic refractive properties of the specimen. A recursive four-parameter χ-squared minimization routine is developed to determine the sphere center, radius, and mean inner potential (Φ0) at each pixel in the phase image. Because of the large number of pixels involved, the statistics associated with determining a single Φ0 value characteristic of a given sphere are quite good. Simulated holograms show that the holographic reconstruction procedure and the χ-squared analysis method are robust. Averaging the Φ0 data derived from ten phase images from ten different polystyrene spheres gives a value of Φ0PS = 8.5 V (σ) = 0.7 V). Specimen charging and electron-beam damage, if present, affect the measurement at a level below the current precision of the experiment.