John J. Uhran

A framed-quadtree approach for determining Euclidean shortest paths in a 2-D environment

In this paper we investigate the problem of finding a Euclidean (L/sub 2/) shortest path between two distinct locations in a planar environment. We propose a novel cell decomposition approach which calculates an L/sub 2/ distance transform through the use of a circular path-planning wave. The proposed method is based on a new data structure, called the framed-quadtree, which combines together the accuracy of high resolution grid-based path planning techniques with the efficiency of quadtree-based techniques, hence having the advantages of both. The heart of this method is a linear time algorithm for computing certain special dynamic Voronoi diagrams. The proposed method does not place any unrealistic constraints on obstacles or on the environment and represents an improvement in accuracy and efficiency over traditional path planning approaches in this area.

Planning Shortest Paths among 2D and 3D Weighted Regions Using Framed-Subspaces

The standard shortest path planning problem determines a collision- free path of shortest distance between two distinct locations in an environment scattered with obstacles. This problem, in fact, corre sponds to a special case of the weighted region problem, in which the environment is partitioned into a set of regions, with some regions (obstacles) having an associated weight of oo and other regions (free space) having a weight of 1. For the general weighted region problem, the environment consists of regions, each of which is as sociated with a certain weight factor. A path through the weighted region incurs a cost that is determined by the geometric distance of the path in that region times that regions weight factor. The weighted region problem can be used to model path planning for autonomous vehicles over different environmental terrains. This paper studies the problem of computing a shortest path between two distinct locations through a 2D or 3D environment consisting of weighted regions. The authors propose a novel cell decomposi tion approach based on new framed-subspace data structures: the weighted framed-quadtree and the weighted framed-octree.

Optimum Signal and Filter Design in Underwater Acoustic Echo Ranging Systems

Optimization of the filter, the signal, and the signal and filter jointly are studied in the sonar environment under noise and reverberation limited conditions. The maximization of the receiver output signal-to-interference ratio is used as a performance criterion with unit energy constraint on both signal and filter. In the filter design problem, the optimum filter function is the solution of a linear integral equation. The kernel of the integral equation is a function of the target and medium scattering functions and the reverberation distribution. In the signal design problem, a similar type of integral equation is obtained as in the filter optimization problem. In the joint signal and filter design problem, it is shown that the optimum signal and filter functions are the solutions to a pair of linear integral equations with the largest (SIR)O. Several examples are investigated for different mediums and reverberation distributions with the finite matrix approximation method. An interative technique is used to compute the joint optimization of signal and filter.

An algebraic method for simulating legal systems

A primarily algebraic technique for simulating social systems has been developed for combined use by engineers and lawyers and has been applied exten sively to studies of felony processing times in the criminal justice system of two counties in the State of Indiana. As a method of non-Monte-Carlo simulation, the present approach overcomes tradi tional impediments such as determination of loops and multiple-function concatenation. preliminary evidence suggests that the simulator has useful capabilities in initial screening of data and in early qualitative studies of systems in which a priori data is not plentiful .

The Equivalence Concept in Criminal Justice Systems

Criminal justice procedures admit process flow diagram representations, which in effect induce equivalences on the data available in public records. Interrogations of the data in the context of such diagrams induce further equivalences. A task for the engineer in the study of criminal justice systems is to develop data display capabilities that reconcile the requirements of these two forms of equivalences. The work reported herein describes all these concepts in detail and illustrates them for jurisdiction in St. Joseph and Marion Counties, State of Indiana.

Determining Optimal Paths, Based on Time and Distance Metric Combinations, in a Dynamic 2-D Environment

Abstract In this paper, the problem of determining optimal paths in a dynamic 2-D environment with multiple, moving obstacles and multiple, moving goals is studied. Presented is a novel cell decomposition approach which generates optimal paths based on a number of different optimality criteria (time, distance, and minimum cost metric combinations). The approach uses a computational geometry technique for sweeping a 3-D space with a plane, called time-sweeping, which allows the calculation of these optimal paths much more efficiently than could be done with traditional path planning approaches in this area.

Automated electronic circuit design: realities and pitfalls

The authors explore the issues associated with setting up an electronic design automation (EDA) facility in an educational environment, pointing out what the reader should look for, what is available now, and what might be available in the future. In the design of such a facility, one needs to be aware of how to go about this process. The authors indicate this through a top-down design technique including what the laboratory should look like, how to break down this laboratory into smaller parts, and their interrelationship to each other and to other parts of the program. Finally, it is shown how to make the essential parts work properly in todays engineering or technology program.<<ETX>>

The value of a comprehensive, integrated assessment program for improving the first-year engineering experience

The College of Engineering at the University of Notre Dame recently completed the fifth year of its first-year Introduction to Engineering course. Each year, the College assesses the quality of the learning experience using various assessment methods including student surveys, student and faculty interviews, student demographic information, student performance in the course and retention rate into the sophomore year. This combination of assessment methods has allowed the College to direct its efforts toward those areas that appear to have the greatest potential for improvement. Our assessment/course improvement cycle has demonstrated the value of an integrated approach to assessing course effectiveness and student progress toward learning outcomes. We have implemented several modifications to the course that have had a positive impact on the retention of all students and, particularly, on the retention of women. The information has also helped us to identify cultural and systemic issues at the University, outside of the course, that affect the retention of engineering students, particularly women, and have enabled us to effect changes at the University level to address those issues. The information has also led us to characterize the types of students at risk for leaving engineering early, allowing the College to engage in proactive efforts to improve the delivery of information to these groups of students. Any single element of this integrated assessment effort might have provided tantalizing clues for necessary changes. But the value of a comprehensive, integrated assessment program lies in the fact that the College can target changes to an identified need, thus achieving positive results

Enhancing the undergraduate engineering curriculum: a collaborative process

This paper describes a process of reviewing and taking action to enhance an undergraduate engineering curriculum. It presents a number of issues associated with defining and implementing change while being sensitive to practical constraints. It addresses issues of organization, goal setting, data gathering and consensus building. Since the process of encouraging change maybe more universally relevant than the specific elements of change, the goal of the paper is to outline a specific set of experiences which may be instructive for others.

Determining conditional shortest paths in an unknown 3-D environment using framed-octrees

A conditional shortest path is a collision-free path of shortest distance which is computed from environmental information which is known at a given time. Based on the techniques of computational geometry, this paper proposes a novel cell decomposition approach for finding conditional shortest paths, in either the L/sub 1/ or L/sub /spl infin// metric, through an unknown 3D environment. The proposed based on a new data structure called the framed-octree, compute a distance transform using a spherical path planning wave. The proposed methods combine together the accuracy of 3D grid-based path planning techniques with the efficiency of octree-based techniques, hence having the advantages of both kinds of techniques and avoiding their disadvantages.