The paper describes a rank-based fitness assignment method for Multiple Objective Genetic Algorithms (MOGAs). Conventional niche formation methods are extended to this class of multimodal problems and theory for setting the niche size is presented. The fitness assignment method is then modified to allow direct intervention of an external decision maker (DM). Finally, the MOGA is generalised further: the genetic algorithm is seen as the optimizing element of a multiobjective optimization loop, which also comprises the DM. It is the interaction between the two that leads to the determination of a satisfactory solution to the problem. Illustrative results of how the DM can interact with the genetic algorithm are presented. They also show the ability of the MOGA to uniformly sample regions of the trade-off surface.

Addresses issues related to partial measurement in variance using a tutorial approach based on the LISREL confirmatory factor analytic model. Specifically, we demonstrate procedures for (a) using "sensitivity analyses " to establish stable and substantively well-fitting baseline models, (b) determining partially invariant measurement parameters, and (c) testing for the invariance of factor covariance and mean structures, given partial measurement invariance. We also show, explicitly, the transformation of parameters from an all-^fto an all-y model specification, for purposes of testing mean structures. These procedures are illustrated with multidimensional self-concept data from low ( « = 248) and high (n = 582) academically tracked high school adolescents. An important assumption in testing for mean differences is that the measurement (Drasgow & Kanfer, 1985; Labouvie,

A program pro le attributes run-time costs to portions of a program's execution. Most pro ling systems su er from two major de ciencies: rst, they only apportion simple metrics, such as execution frequency or elapsed time to static, syntactic units, such as procedures or statements; second, they aggressively reduce the volume of information collected and reported, although aggregation can hide striking di erences in program behavior. This paper addresses both concerns by exploiting the hardware counters available in most modern processors and by incorporating two concepts from data ow analysis { ow and context sensitivity{to report more context for measurements. This paper extends our previous work on e cient path pro ling to ow sensitive pro ling, which associates hardware performance metrics with a path through a procedure. In addition, it describes a data structure, the calling context tree, that e ciently captures calling contexts for procedure-level measurements. Our measurements show that the SPEC95 benchmarks execute a small number (3{28) of hot paths that account for 9{98 % of their L1 data cache misses. Moreover, these hot paths are concentrated in a few routines, which have complex dynamic behavior. 1

The first (and for some still the only) multivariate B-spline is what today one would call the simplex spline, since it is derived from a simplex, and in distinction to other polyhedral splines, such as the cone spline and the box spline. The simplex spline was first talked about in 1976. However, it was only after Micchelli [Micchelli, 1980] established recurrence relations for them that the topic of simplex splines and other multivariate B-splines really took o. Their cousins, the box splines, were thought particularly attractive because their recurrence relations turned out to be very simple indeed. It was, therefore, a shock to me when, in the process of doing my bit on the book [de Boor, Hollig, Riemenschneider, 1993], I found that it was nontrivial to make effective use of these recurrence relations. It is one purpose of this note to relate my difficulties and how I tried to deal with them. This is not the place to give an introduction to box spline theory, nor to review the relevant literature. Rather, the reader is urged to consult [de Boor, Hollig, Riemenschneider, 1993] for missing details and the proper literature references (as well as for many illustrations, two of which are reproduced below).

This paper surveys the design of embedded computer systems, which use software running on programmable computers to im-plement system functions. Creating an embedded computer system which meets its performance, cost, and design time goals is a hardware-software co-design problewhe design of the hard-ware and software components influence each other. This paper emphasizes a historical approach to show the relationships be-tween well-understood design problems and the as-yet unsolved problems in co-design. We describe the relationship between hard-ware and sofhvare architecture in the early stages of embedded system design. We describe analysis techniques for hardware and software relevant to the architectural choices required for hard-ware-software co-design. We also describe design and synthesis techniques for co-design and related problems.

To be an effective platform for performance-sensitive real-time and embedded applications, off-the-shelf CORBA middleware must preserve the communication-layer quality of service (QoS) properties of applications end-to-end. However, the standard CORBA GIOP/IIOP interoperability protocols are not well suited for applications that cannot tolerate the message footprint size, latency, and jitter associated with general-purpose messaging and transport protocols. It is essential, therefore, to develop standard pluggable protocols frameworks that allow custom messaging and transport protocols to be configured flexibly and used transparently by applications. This paper provides three contributions to research on pluggable protocols frameworks for performance-sensitive distributed object computing (DOC) middleware. First, we outline the key design challenges faced by pluggable protocols developers. Second, we describe how we resolved these challenges by developing a pluggable protocols framewo...

Modern commodity operating systems are large and complex systems developed over many years by large teams of programmers, containing hundreds of thousands of lines of code. Consequently, it is extremely difficult to add significant new functionality to these systems. In response to this problem, a number of recent research projects have explored novel operating system architectures to support untrusted extensions, including SPIN, VINO, Exokernel, and Fluke. Unfortunately, these architectures require substantialimplementation effort and are not generally available in commodity systems. In contrast, by leveraging the technique of interposition, we have designed and implemented a prototype extension system called SLIC which requires only trivial operating system

English-speaking college students who were enrolled in a German course read a 762-word German language story presented by a computer program. For key words in the story, students could choose to see a translation on the screen in English (i.e., verbal annotation) or view a picture or video clip representing the word (i.e,, visual annotation), or both. Students remembered word translations better when they had selected both visual and verbal annotations during learning than only 1 or no annotation; students comprehended the story better when they had the opportunity to receive their preferred mode of annotation. Results are consistent with a generative theory of multimedia learning that assumes that learners actively select relevant verbal and visual information, organize the information into coherent mental representations, and integrate these newly constructed visual and verbal representations with one another. Current developments in information technologies have resulted in rapid advances in the application of instructional and educational technology. There seem to be, however, only small advances in corresponding basic research on

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This paper describes the design and performance of an object-oriented communication framework being developed by the Health Imaging division of Eastman Kodak and the Electronic Radiology Laboratory at Washington University School of Medicine. The framework is designed to meet the demands of next-generation electronic medical imaging systems, which must transfer extremely large quantities of data efficiently and flexibly in a distributed environment. A novel aspect of this framework is its seamless integration of flexible high-level CORBA distributed object computing middleware with efficient low-level socket network programming mechanisms. In the paper, we outline the design goals and software architecture of our framework, describe how we resolved design challenges, and illustrate the performance of the framework over high-speed ATM networks. 1 Introduction The demand for distributed electronic medical imaging systems (EMISs) is pushed by technological advances and pulled by economic...