FIDEX: An expert system for satellite diagnostics

A Fault Isolation and Diagnostic Expert system (FIDEX) was developed for communication satellite diagnostics. It was designed specifically for the 30/20 GHz satellite transponder. The expert system was designed with a generic structure and features that make it applicable to other types of space systems. FIDEX is a frame based system that enjoys many of the inherent frame base features, such as hierarchy that describes the transponder's components, with other hierarchies that provide structural and fault information about the transponder. This architecture provides a flexible diagnostic structure and enhances maintenance of the system. FIDEX also includes an inexact reasoning technique and a primitive learning ability. Inexact reasoning was an important feature for this system due to the sparse number of sensors available to provide information on the transponder's performance. FIDEX can determine the most likely faulted component under the constraint of limited information. FIDEX learns about the most likely faults in the transponder by keeping a record of past established faults. FIDEX also has the ability to detect anomalies in the sensors that provide information on the transponders performance

Resilience of multi-photon entanglement under losses

We analyze the resilience under photon loss of the bi-partite entanglement present in multi-photon states produced by parametric down-conversion. The quantification of the entanglement is made possible by a symmetry of the states that persists even under polarization-independent losses. We examine the approach of the states to the set of states with a positive partial transpose as losses increase, and calculate the relative entropy of entanglement. We find that some bi-partite distillable entanglement persists for arbitrarily high losses.Comment: 5 pages, 3 figures, title changed, minor typographic errors correcte

A Building-Block Approach to Industrial Controls Laboratories Using Programmable Logic Controllers

Industrial control systems design often incorporates reusable sections of prior design that can easily be adapted for new machine and process control systems. For instance, inclusion of a tri-mode control structure (Manual, Automatic and Set-up modes) often becomes a ‘cut and paste’ section from a previous control system design. The prior design is already proven, and development time is available for the newer aspects of the control system. This building-block method can also be used to structure university laboratory exercises for EET (Electrical Engineering Technology) industrial controls design courses. Reusing software sections from previous laboratories can enhance the student’s design capability by focusing lab time on the new problem instead of recreating the old structures. This paper describes a semester-long industrial controls laboratory using programmable logic controllers (PLC) as the primary lab equipment. It describes twelve increasingly difficult PLC laboratory experiments that generally build on the components of the prior labs. The final lab assignment is an open-ended team project to design a complete system for a typical industrial machine or process. All of the PLCs are networked to provide the students with communications content within the lab experience. The pedagogical features of the laboratory exercises are illustrated and results from student comments and numerical ratings of the effectiveness of the lab exercises and equipment are also included in the paper

Intelligent fault isolation and diagnosis for communication satellite systems

Discussed here is a prototype diagnosis expert system to provide the Advanced Communication Technology Satellite (ACTS) System with autonomous diagnosis capability. The system, the Fault Isolation and Diagnosis EXpert (FIDEX) system, is a frame-based system that uses hierarchical structures to represent such items as the satellite's subsystems, components, sensors, and fault states. This overall frame architecture integrates the hierarchical structures into a lattice that provides a flexible representation scheme and facilitates system maintenance. FIDEX uses an inexact reasoning technique based on the incrementally acquired evidence approach developed by Shortliffe. The system is designed with a primitive learning ability through which it maintains a record of past diagnosis studies

The Legal Arizona Workers Act and Preemption Doctrine

in recent years, a spate of states passed laws regulating the employment of undocumented immigrants. This Note argues that laws that impose civil sanctions on employers that hire undocumented immigrants are preempted by both federal immigration law and federal labor law. The Note focuses specifically on the Legal Arizona Workers Act because it went into effect in 2008 and has amassed more than two years\u27 worth of data on its enforcement, and because it is touted as the harshest state anti-immigration measure to date. This Note examines the law\u27s impacts and argues that practitioners nationwide should challenge the Legal Arizona Workers\u27 Act, as well as the proliferation of similar state laws that threaten civil rights, business and labor interests, and the supremacy of the federal Constitution

GTEX: An expert system for diagnosing faults in satellite ground stations

A proof of concept expert system called Ground Terminal Expert (GTEX) was developed at The University of Akron in collaboration with NASA Lewis Research Center. The objective of GTEX is to aid in diagnosing data faults occurring with a digital ground terminal. This strategy can also be applied to the Very Small Aperture Terminal (VSAT) technology. An expert system which detects and diagnoses faults would enhance the performance of the VSAT by improving reliability and reducing maintenance time. GTEX is capable of detecting faults, isolating the cause and recommending appropriate actions. Isolation of faults is completed to board-level modules. A graphical user interface provides control and a medium where data can be requested and cryptic information logically displayed. Interaction with GTEX consists of user responses and input from data files. The use of data files provides a method of simulating dynamic interaction between the digital ground terminal and the expert system. GTEX as described is capable of both improving reliability and reducing the time required for necessary maintenance

Multi-Partite Entanglement Inequalities via Spin Vector Geometry

We introduce inequalities for multi-partite entanglement, derived from the geometry of spin vectors. The criteria are constructed iteratively from cross and dot products between the spins of individual subsystems, each of which may have arbitrary dimension. For qubit ensembles the maximum violation for our inequalities is larger than that for the Mermin-Klyshko Bell inequalities, and the maximally violating states are different from Greenberger-Horne-Zeilinger states. Our inequalities are violated by certain bound entangled states for which no Bell-type violation has yet been found.Comment: 4 pages, 2 tables, 1 figure. A truncated version is published in Physical Review Letters, volume 95 issue 18, 180402 (October 2005

Child Pedestrian Injury in an Urban Setting: Descriptive Epidemiology

This study describes the epidemiology of pedestrian injuries to children and adolescents (ages <20) in an urban setting, providing analyses of environmental and pedestrian variables. Anonymous data were obtained for all motor vehicle crashes occurring in New York City over a 7-year period (1991-1997). Among 693,283 crashes, 97,245 resulted in injuries to 100,261 pedestrians of whom 32,578 were under age 20. Using census counts for the denominator, the overall incidence of pediatric pedestrian injuries was 246/100,000 per year, and the case fatality rate was 0.6%. Incidence rates peaked in the 6-14 year age group, and showed a modest annual decline during the study period. Younger children were more likely to be struck mid-block and during daylight hours, whereas adolescents were more likely to be struck at intersections and at night. For younger children, there was a sharp peak in incidence during the summer months. Road and weather conditions did not appear to affect injury risk. These results help identify priorities for child pedestrian injury prevention and education, inform public health policy, and direct emergency medical health services resource allocation

TILA ‘Finance’ and ‘Other’ Charges in Open-End Credit: The Cost-of Credit Principle Applied to Charges for Optional Products or Services

The thesis of this article is that a more workable approach to characterizing fees for optional products and services is possible by focusing on charges that represent payment for discrete products or services of value to the consumer, freely chosen by consumers as contract options which do not affect the amount of credit available to the consumer, the consumer\u27s access to it, or the allocation of payment responsibility and credit risk in the transaction or plan. In other words, these fees are for separate-or separable-purchases, analogous to subsequent events in closed-end credit that require no new disclosure or adjustment in the disclosed finance charge. 20 The primary focus of this article is on open-end credit because it involves greater interpretive and operational challenges. This article first explains, in Part II, the critical role of finance charges and other charges as costs imposed in credit transactions and thus elements in the TILA disclosure scheme. Part III provides a broad overview of the marketing and economic considerations that influence how creditors price their products, concluding that there is a long-accepted economic framework for identifying the true costs of credit. The next section, Part IV, analyzes the existing legal guidance on whether and when charges for optional products or services are finance charges or other charges in the TILA regime, suggesting that the current law lacks a consistent and coherent principle. Parts V and VI then propose a set of extreme alternative approaches, and several intermediate approaches on how TILA might deal with optional charges, and analyze how those approaches lack economic integrity. Finally, Part VII suggests a different approach that builds on accepted economic premises and characterizes charges as finance charges only when they compensate the creditor for one of the four recognized components of the cost of credit-origination, servicing, funding, and risk. Recognition of this principle, the authors suggest, can be accomplished, without amendments to TILA or Regulation Z, by amendments to the Official Staff Commentary