John Wu

The role of human factors in telehealth

The purpose of this article is to provide an overview of the field of human factors (HFs) and its role in telehealth. We discuss HF concepts and methodologies that affect the design, implementation, and evaluation of telehealth applications and provide examples from numerous application areas that highlight the significance of HF principles and methodologies. We also provide recommendations for inclusion of HFs in telehealth system design and evaluation, and discuss resulting implications for system designers, practitioners, vendors, and policy makers.

Modeling infection spread and behavioral change using spatial games

This paper presents a methodology that combines information transmission, contact networks, and changes of human behaviors in modeling the dynamics of infectious diseases. The methodology presented is based on a spatial evolutionary game with additional information representing human behavior. This approach is used to model the transmission process of infectious disease, which emphasizes the human response and information transmission in a social context. It combines the advantages of evolutionary game theory with modeling the spontaneous changes of human behaviors based on the balance of benefits and costs. The model assumes rational participants who use information acquired to make individual decisions. This novel modeling approach shows the global spread of infection considering an individual human behavior.

A novel optical technique for measuring 5-axis surface movement

This paper describes a novel optical system capable of measuring 5-axis (five degrees of freedom) object surface movement without the need for special surface preparation or stringent alignment. The compact optical system is based on electronic speckle photography (ESP) and is designed to be insensitive to out-of-plane movement. Experiments were conducted to measure the 5-axis motion simulated by a 6-axis motion system. The results show that the optical system accurately resolves the motion on every axis successfully, with the expected insensitivity to out-of-plane displacements. A possible application of the technique in strain measurement is also addressed in the paper.

An Autonomous Multi-Agent Simulation Model for Acute Inflammatory Response

This research proposes an agent-based simulation model combined with the strength of systemic dynamic mathematical model, providing a new modeling and simulation approach of the pathogenesis of AIR. AIR is the initial stage of a typical sepsis episode, often leading to severe sepsis or septic shocks. The process of AIR has been in the focal point affecting more than 750,000 patients annually in the United State alone. Based on the agent-based model presented herein, clinicians can predict the sepsis pathogenesis for patients using the prognostic indicators from the simulation results, planning the proper therapeutic interventions accordingly. Impressively, the modeling approach presented creates a friendly user-interface allowing physicians to visualize and capture the potential AIR progression patterns. Based on the computational studies, the simulated behavior of the agent-based model conforms to the mechanisms described by the system dynamics mathematical models established in previous research.

Analogy-based multiple process planning system with resource conflicts

Computer-aided process planning is becoming a widely prevalent technology in modern manufacturing systems. The research presented here describes a new methodology for generating process plans based on the analogy deductive paradigm. The method uses rules that represent relations between two shapes and allow inference of the type: shape A is to shape B as C is to D, where usually D is the unknown shape. The system uses backward chaining and therefore gradually converts the part from its finished (designed) form into its initial form. This method can generate multiple process plans for each given part; the paper also presents a method of selecting the best combination of process plans to maximize the production rate of that part. Once the dominant combination of plans is selected, the paper presents a method to calculate a proper production quantity for each process plan. This method is based on “coalition theory” and uses Shapley values to evaluate each member of such a coalition. The system has been implemented on a SUN workstation using Quintus Prolog and C++. The current implementation considers prismatic parts only.

Determining the Remaining Prestress Force in a Prestressed Concrete Crosstie

The research presented herein focuses on determining the amount of internal prestressing force and bending resistance that is necessary to provide a durable long-term concrete railroad tie. In order to accomplish this, the researchers conducted a systematic evaluation of existing concrete ties that successfully withstood over 25 years of service in track. An experimental method for determining the remaining prestress force in these existing prestressed concrete railroad ties is currently under development.The ties are first loaded in the upside-down orientation, with supports located at the rail seats, and two point loads applied at the center of the tie. A loading rate of 1,000 lb/min was used to initiate flexural cracking in the center of the tie. Once cracking was observed, the ties underwent 200 cycles of loading to reduce the friction between the prestressing tendons and the concrete. When the cycling was completed, the existing crack was instrumented with an extensometer to measure the Crack Opening Displacement (COD). The ties were loaded once more at 1,000 lb/min to develop a Load vs. COD relation.A systematic method of determining the load required to reopen the crack from the Load vs. COD relation is being developed using ties cast at a manufacturing plant that were instrumented with internal vibrating-wire strain gages. Using the load required to reopen the crack, along with the known cross-sectional properties at the center of the tie, the remaining prestress force is calculated through equilibrium of forces. This method allows for the determination of the remaining prestress force in a member with known section properties to be obtained through load testing.Copyright