Specific Performance Level Research Articles

A slack-based measure of efficiency in context-dependent data envelopment analysis

Data envelopment analysis (DEA) has been proven as an excellent data-oriented performance evaluation method when multiple inputs and outputs are present in a set of peer decision-making units (DMUs). In the DEA literature, a context-dependent DEA is developed to provide finer evaluation results by examining the efficiency of DMUs in specific performance levels based upon radial DEA efficiency scores. In DEA, non-zero input and output slacks are very likely to present after the radial efficiency score improvement. Often, these non-zero slack values represent a substantial amount of inefficiency. Therefore, in order to fully measure the inefficiency in DMU's performance, it is very important to also consider the inefficiency represented by the non-zero slacks in the context-dependent DEA. This study proposes a slack-based context-dependent DEA which allows a full evaluation of inefficiency in a DMUs performance. By using slack-based efficiency measure, we obtain different frontier levels and more appropriate performance benchmarks for inefficient DMUs.

Context-dependent data envelopment analysis—Measuring attractiveness and progress

Data envelopment analysis (DEA) is a methodology for identifying the efficient frontier of decision making units (DMUs). Context-dependent DEA refers to a DEA approach where a set of DMUs are evaluated against a particular evaluation context. Each evaluation context represents an efficient frontier composed by DMUs in a specific performance level. The context-dependent DEA measures (i) the attractiveness when DMUs exhibiting poorer performance are chosen as the evaluation context, and (ii) the progress when DMUs exhibiting better performance are chosen as the evaluation context. The current paper extends the context-dependent DEA by incorporating value judgment into the attractiveness and progress measures. The method is applied to measuring the attractiveness of 32 computer printers. It is shown that the attractive measure helps (i) customers to select the best option, and (ii) printer manufacturers to identify the potential competitors.

Performance-Based Evaluation of Reinforced Concrete Building Exterior Joints for Seismic Excitation

Beam-column joints of nonductile reinforced concrete buildings that were built prior to the current seismic code provisions have been investigated using several performance-based criteria. Four half-scale reinforced concrete exterior joints were tested to investigate their behavior in a shear-critical failure mode. The joints were subjected to quasi-static cyclic loading, and their performance was examined in terms of lateral load capacity, drift ratio, axial load reduction in the column at high drift ratios, joint shear strength, ductility, shear deformation angle of the joint, and residual strength. Two levels of axial compressive column load were investigated to determine how this variable might influence the performance of the joint. Specific performance levels for this type of reinforced concrete joint were established and a comparison was made to current design and rehabilitation standards. A limit states model was established, which could be used for performance evaluation or seismic rehabilitation.

Fundamental flow cytometer properties governing sensitivity and resolution

The fundamental properties of a flow cytometer that govern its capacity to detect and resolve dim fluorescent particles are 1) the efficiency with which it can convert a photon emitted by a fluorochrome into a photoelectron at the photocathode of the photomultiplier tube and 2) the amount of optical background noise that is collected along with the fluorescence emission from the particle. Either of these properties alone is insufficient to predict an instrument's performance. Thus, to characterize a flow cytometer, both of these properties need to be determined. To determine these properties, one must not only consider the optical characteristics of the instruments but also understand the impact of the signal processing on the data collected. After the collection efficiency and the optical background noise level are determined, it is possible to predict the instrument's performance. A specific flow cytometer performance level is not unique to only one pair of these properties. To achieve a specific level of instrument performance, whole families of pairs of these properties are possible.

An interactive scheduler for a wafer probe centre in semiconductor manufacturing

This paper analyses production operations and scheduling constraints on a wafer probe centre in semiconductor manufacturing. Such actions as lot split and hot lot preemption are discussed. Due to the combinatorial difficulties of scheduling problems with sequence-dependent setup costs and multiple criteria, a humancomputer interactive scheduler named the 'interactive computer aided scheduling system' (ICASS) is proposed. This ICASS can search for schedules to achieve a specific performance level set by a human. An experiment was conducted on a wafer probe centre to compare the performance of ICASS with that of a manual approach and six priority rules. The results indicate that ICASS spent less scheduling time and provided better schedules than the manual approach. All the six priority rules yielded only poor schedules with unbalanced performance in three kinds of criteria, although they were beneficial in computation time.

Performance of "standardized examinees" in a standardized-patient examination of clinical skills.

As a first step in testing the utility of using trained "standardized examinees" (SEs) as a quality-assurance measure for the scoring process in a standardized-patient (SP) examination, to test whether medical residents could simulate students in an SP examination and perform consistently to specified levels under test conditions. Fourth-year students from the Baltimore-Washington Consortium for SPs participated in a National Board of Medical Examiners Prototype Examination of clinical skills consisting of twelve 15-minute student-patient encounters in 1994-95. For this examination, internal medicine residents were trained to act as ordinary candidates and to achieve target scores by performing to a set level on specific checklist items used by SPs for recording interviewing, physical-examination, and communication skills. The "strong SEs" were trained to score 80% correct on six of the examination's 12 cases (study cases), and the "weak SEs" were trained to score 40% correct on the same six cases. The strong and weak SEs' checklist scores on the study cases were compared through independent, two-tailed t-tests. When there was less than 85% agreement on specific checklist items in each case between the SE training and the SP recording, videotapes of the cases were reviewed; in such cases an SE's performance was the final score agreed upon after review. Seven SEs took the SP examination and were not detected by the SPs. There was a total of 84 discrepancies between predicted and recorded checklist scores across 659 checklist items in 40 encounters scored by the SPs. After correcting the discrepancies based on videotape review, the estimated actual mean score was 77.3% for the strong SEs and 44.0% for the weak SEs, and was higher for the strong SEs in each study case. The overall fidelity of the SEs to their training was estimated to be 97%, and the overall SP accuracy was estimated to be 91%. The videotape review revealed 47 training-scoring discrepancies, most in the area of communication skills. This study suggests that SEs can be trained to specific performance levels and may be an effective internal control for a high-stakes SP examination. They may also provide a mechanism for refining scoring checklists and for exploring the validity of SP examinations.

Advanced thrust chamber materials for Earth storable bipropellant rocket engines

The successful incorporation of high performance nitrogen tetroxide oxidizer and the monomethylhydrazine fuel bipropellant rocket engines into integrated propulsion systems utilized on satellites and spacecraft is due in part to the use of high melting point material systems for the combustion chamber and exit nozzle. The 445 N attitude control rocket engine used on the Apollo service module and lunar module embodied molybdenum as the combustion chamber material. This material system was soon replaced by the niobium (columbium) alloy material system which is used in a majority of the small liquid rocket engines in service today. The material operating limit of 1600°C with the R-512 oxidation coating is more than adequate for the demonstrated performance levels of nearly 2900 N s/kg but the structural-mechanical differences between the coating and the base metal limits the operation time at temperature when the chamber is subjected to thermal cycling. New material systems such as the silicon carbide matrix system, rhenium and zirconium oxide have been evaluated and have demonstrated increased temperature capabilities and less sensitivity to the thermal cycling characteristic of rocket engine operation when subjected to station keeping and on-orbit attitude control. Tests conducted at Societe Europeenne de Propulsion with the silicon carbide material system and tests conducted at Marquardt with a layered rhenium and zirconium oxide matrix material system demonstrated increase durability at higher engine performance levels. Combustion chamber temperatures up to 2100°C were documented at specific impulse performance levels of 3000 N s/kg.

APPLICATION OF LEARNING THEORY TO AN ARTIFICIAL NEURAL NETWORK THAT DETECTS INCIPIENT FAULTS IN SINGLE-PHASE INDUCTION MOTORS

The generalization ability of a neural network in a specific application is of interest to many neural network designers. In this paper, learning theory is applied to a neural network used for incipient fault detection in single-phase induction motors. This paper will show that learning theory can help determine the proper number of training examples needed to reach a specific performance level, so that excessive and unnecessary training examples can be avoided. Comparisons of the results of learning theory and Monte Carlo estimate are presented, showing that learning theory is a useful and reliable tool to obtain information about the training process of a given neural network.

Industrial salespeople as a source of market information

Marketing scholars have suggested that salespeople can play an important role in firms' ongoing efforts to understand their customers' perceptions and preferences. However, very few studies have examined the accuracy of the information which salespeople are able to provide. This article reports the results of a survey of an industrial marketer's customers, outside salespeople, and telemarketing salespeople about market information. Salespeople can accurately assess the importance of various product and service attributes to their customer. However, salespeople are unable to gauge the specific performance levels expected by their customers. Interestingly, telemarketing salespeople are approximately as accurate as outside salespeople with respect to both types of information. The article explains these results and discusses their managerial implications.

Independent sitting development and the emergence of associated motor components.

The purpose of this preliminary study was to examine the relationship between the emergence of independent sitting ability and the presence of underlying motor components (reflexes, automatic postural reactions, and flexion and extension movement patterns). Ten full-term, nonhandicapped infants were tested longitudinally for the presence of underlying motor components as they attained three performance levels of sitting ability between the ages of 4 and 7 months. A total of 26 observations was collected across the 10 infants. The time of each testing session was based on the infants' attainment of each successive sitting performance level. Underlying motor components were assessed at each testing session to determine whether a consistent sequence of component emergence developed and whether those components were associated with a specific performance level of sitting. The results indicated that no consistent sequential pattern of motor component emergence existed. The data showed that the pattern of underlying component emergence was highly variable across the infants at similar levels of sitting ability, although some components were associated highly with specific performance levels. The data suggest that the attainment of independent sitting in nonhandicapped infants is described best as a continuous developmental process, rather than a discontinuous "stage" phenomenon.

Methods for Evaluating the Quality of Oilfield Tubular Inspections

Summary This paper discusses methods and test procedures for conducting field evaluations to determine the effectiveness of oilfield tubular-inspection equipment and personnel. Specific requirements and equations are proposed for qualifying magnetic particle, ultrasonic, eddy current, radiographic, optical, and mechanical nondestructive test equipment. The design and use of pip standards to check automated pipe-inspection systems are also described. By incorporation of the methods pipe-inspection systems are also described. By incorporation of the methods developed in this paper, nondestructive inspection services can be qualified with respect to the pipe diameter, weight, grade, or critical application of the tubular. Introduction In drilling for oil and gas, we are encountering ever-increasing challenges in the form of more hostile environments. Higher pressures. greater temperatures, corrosive gases, and deeper, deviated wellbores present new problems. Because of these challenges, the quality of problems. Because of these challenges, the quality of tubulars that are used to complete the well becomes even more critical. The oil industry currently ensures the quality of new tubulars placed downhole through nondestructive inspections conducted in the field or at the pipeyard. The inspection equipment typically is designed to locate seams, laps, pill, slugs and thin-wall areas that result from the manufacturing process, as well as mechanical damage from handling. Oilfield tubulars are one of the most important factors that affect the production and safety of any oil or gas well. In particular, tubing and casing are subjected to high tension loads from the weight of the string, burst loads from internal production pressures, collapse loads from external formation pressures, bending loads from wellbore deviations, and other severe conditions, such as sour-gas environments. And finally, these tubulars may remain in production for as long as 20 years with corrosion taking production for as long as 20 years with corrosion taking its toll. The majority of today's oilfield tubulars are made of carbon or alloy steels and are manufactured by the seamless piercing and rolling process. The cost of these tubulars often represents 20 to 40% of the drilling program cost. but the cost of a tubular failure can be even more dramatic. Pipeyard inspection reports for new tubing and casing indicate that about 20% of domestic tubulars are rejected when held to API specifications. Therefore, the pipeyard inspection is critical in maintaining the quality pipeyard inspection is critical in maintaining the quality of the wellbore. Service companies provide tubular inspections for most oil companies. The quality of these inspections varies significantly from region to region. One of the principal reasons for this variation is a lack of specifications for the nondestructive testing (NDT) of oilfield tubulars. Once a specification has been established, the next step is to evaluate and to qualify the inspection company during field evaluations in that region. Existing NDT specifications, such as the American Soc. of Nondestructive Testing (ASNT), the American Soc. for Testing and Materials (ASTM), or API Specifications, are neither detailed enough nor directed specifically enough to the oil field to allow the inspection equipment to be evaluated and qualified to a particular level. The final step in among quality inspections is through adequate supervision and periodic audits of equipment and personnel. periodic audits of equipment and personnel. This paper addresses the specific performance levels for NDT equipment and personnel for oilfield tubular inspections. The requirements developed at Exxon Production Research Co. involve theoretical calculations, review Production Research Co. involve theoretical calculations, review of the existing inspection methodology, and experimental testing in electromagnetics, ultrasonics, and radiography. Then these requirements were incorporated into a procedure for conducting field evaluations to determine and to maintain the quality of oilfield tubular inspections. Field Evaluations of Oilfield Inspection Operations Field evaluations of an oilfield inspection operation consists of testing and documenting information in three principal areas: (1) automated pipe-body inspections, principal areas:automated pipe-body inspections,special end-area and prove-up inspections, andpersonnel certification and reference documents. These areas are discussed individually and described in more detail to pert-nit field evaluations to be conducted. Performance specifications that serve as a basis for evaluating the quality of the inspections are described. When field evaluations are made, all pertinent information that describes the inspection equipment, personnel, and procedures should be recorded. Identification numbers should be assigned to the inspection equipment when no other identifiable markings exist to allow easy identification at a later date. This also serves as a list that describes the equipment available at the particular inspection site. Automated Pipe-Body Inspections The geometrically uniform section of the pipe (all but the last few feet from either end) typically is inspected by an automated inspection system capable of scanning pipe at about 1 ft/sec [0.3 m/s]. JPT p. 88

Catadioptric lens with aberrations balanced by aspherizing one surface

In this paper we describe an optical system with one surface aspherized to give a specific level of performance and to equalize the intensity profiles of star images over the field. The system was a 25.4-cm EFL, 5.8° field, f/1.53 catadioptric Cassegrain. It was designed to determine the attitude of a space platform by detecting and mapping the geometric pattern of stars observed to ninth visual magnitude. Aberrations were controlled over a 0.5–1.1-μm spectral region. We compare the polychromatic performance of our design to one conventionally optimized. We also describe how the spherical substrate base radius was chosen to minimize glass removal.