A Simulation Study of the Relative Efficiency of the Minimized Integrated Square Error Estimator (L2E) For Phase I Control Charting

Parameter estimates used in control charting, the sample mean and variance, are based on maximum likelihood estimation (MLE). Unfortunately, MLEs are not robust to contaminated data and can lead to improper conclusions regarding parameter values. This article proposes a more robust estimation technique; the minimized integrated square error estimator (L2E)

Adapting the Access Northwind Database to Support a Database Course

A common problem encountered when teaching database courses is that few large illustrative databases exist to support teaching and learning. Most database textbooks have small ‘toy’ databases that are chapter objective specific, and thus do not support application over the complete domain of design, implementation and management concepts across a single database. The Northwind Traders sample database is available by Microsoft for download and use in Microsoft Access, and illustrates transactional processing for a fictitious company that imports (purchases) and exports (sells) specialty foods from around the world. The database contains sample tables, queries, forms, reports, Macros, VBA Class Objects, functions and modules, and other database features. Although the primary purpose for the database is to serve as an illustrative design template for students and practitioners, unfortunately the database and business processes are largely undocumented. This paper attempts to more completely document the business processes, including establishing business rules, describing relationships and participations, and discusses some problems with the existing design. Following understanding of the database and associated business processes, this paper can be used as both a teaching tool and a guide for practitioners using the Northwind Traders sample database as a design template. Additionally, it has been used successfully to introduce the concept of business processes and mapping them in an underlying database in introductory ERP courses

Association patterns and foraging behaviour in natural and artificial guppy shoals

Animal groups are often nonrandom assemblages of individuals that tend to be assorted by factors such as sex, body size, relatedness and familiarity. Laboratory studies using fish have shown that familiarity among shoal members confers a number of benefits to individuals, such as increased foraging success. However, it is unclear whether fish in natural shoals obtain these benefits through association with familiars. We investigated whether naturally occurring shoals of guppies, Poecilia reticulata, are more adept at learning a novel foraging task than artificial (in which we selected shoal members randomly) shoals. We used social network analysis to compare the structures of natural and artificial shoals and examined whether shoal organization predicts patterns of foraging behaviour. Fish in natural shoals benefited from increased success in the novel foraging task compared with fish in artificial shoals. Individuals in natural shoals showed a reduced latency to approach the novel feeder, followed more and formed smaller subgroups compared to artificial shoals. Our findings show that fish in natural shoals do gain foraging benefits and that this may be facilitated by a reduced perception of risk among familiarized individuals and/or enhanced social learning mediated by following other individuals and small group sizes. Although the structure of shoals was stable over time, we found no direct relationship between shoal social structure and patterns of foraging behaviour

Mapping Relational Algebra Operators into SQL Queries: A Database Case Study

Relational algebra operators and mapping to resulting structured query language (SQL) queries are among the most important concepts and skills for students taking a course in database design and implementation, especially those majoring in IS/IT. The most typical relational algebra operators mapped to foundational SQL include unions and intersections, as well as other relational operators applied to these operators, including differences and various joins. Unfortunately, few textbooks or external resources provide ample opportunity for students to apply the full set of most common relational algebra operators mapped to resulting SQL over a single unified case. Most database textbooks exemplify each separate relational algebra construct to a single, sparse (although visually-stimulating) example, wherein the full set of operators is not near fully exemplified. This paper presents an overview of a case example that exemplifies and maps a more complete set of relational algebra operators in related SQL operations across a unified case. The case replicates the author’s real experience in building a database solution for an online retailer of sporting goods products. It is hoped that this case example will help database teachers more effectively teach relational algebra concepts, the subsequent mapping to SQL, and resulting queries, as well as provide students a greater understanding of relational algebra and mapping to SQL. Although the case example is exemplified in Microsoft Access 2010/2013, the case can be modified and presented using any relational database management system (RDBMS)

Monte Carlo Simulation Design for Evaluating Normal-Based Control Chart Properties

The advent of more complicated control charting schemes has necessitated the use of Monte Carlo simulation (MCS) methods. Unfortunately, few sources exist to study effective design and validation of MCS methods related to control charting. This paper describes the design, issues, considerations and limitations for conducting normal-based control chart MCS studies, including choice of random number generator, simulation size requirements, and accuracy/error in simulation estimation. This paper also describes two design strategies for MCS for control chart evaluations and provides the programming code. As a result, this paper hopes to establish de facto MCS schemes aimed at guiding researchers and practitioners in validation and control-chart evaluation MCS design

A Simulation Study Of The Impact Of Forecast Recovery For Control Charts Applied To ARMA Processes

Forecast-based schemes are often used to monitor autocorrelated processes, but the resulting forecast recovery has a significant effect on the performance of control charts. This article describes forecast recovery for autocorrelated processes, and the resulting simulation study is used to explain the performance of control charts applied to forecast errors

ABET Accreditation of IS and IT Programs in 2013

The Accreditation Board for Engineering and Technology (ABET) has been accrediting engineering and computer science for many years. In recent years ABET has been accrediting Information Systems and Information Technology programs. ABET first accredited IS in 2000 and IT in 2003. ABET appears to have become the standard accreditation for IT and in the spring of 2014 there are 25 IT programs accredited by ABET. There are 38 IS programs accredited by ABET since 2000. This paper looks at the IS and IT ABET accredited programs and examines the common features and differences of these related accredited programs

A LinkedIn Analysis of Career Paths of Information Systems Alumni

Information harvested from the LinkedIn profiles for 175 graduates of an Information Systems program at a mid-sized comprehensive university in the southeastern USA are summarized in this investigation. The current investigation was undertaken to examine the extent to which LinkedIn profiles are able to provide a more realistic picture of entry-level jobs held by program alumni and subsequent career progress. Additionally, our results suggest that LinkedIn profiles can help answer questions such as: what jobs do IS graduates get, what does the career of an IS professional typically look like, and can IS graduates successfully transition from technical to managerial positions? Our findings also suggest that information in LinkedIn profiles can be used to assess the long-term outcomes of IS programs

Crossover interference and sex-specific genetic maps shape identical by descent sharing in close relatives

Simulations of close relatives and identical by descent (IBD) segments are common in genetic studies, yet most past efforts have utilized sex averaged genetic maps and ignored crossover interference, thus omitting features known to affect the breakpoints of IBD segments. We developed Ped-sim, a method for simulating relatives that can utilize either sex-specific or sex averaged genetic maps and also either a model of crossover interference or the traditional Poisson model for inter-crossover distances. To characterize the impact of previously ignored mechanisms, we simulated data for all four combinations of these factors. We found that modeling crossover interference decreases the standard deviation of pairwise IBD proportions by 10.4% on average in full siblings through second cousins. By contrast, sex-specific maps increase this standard deviation by 4.2% on average, and also impact the number of segments relatives share. Most notably, using sex-specific maps, the number of segments half-siblings share is bimodal; and when combined with interference modeling, the probability that sixth cousins have non-zero IBD sharing ranges from 9.0 to 13.1%, depending on the sexes of the individuals through which they are related. We present new analytical results for the distributions of IBD segments under these models and show they match results from simulations. Finally, we compared IBD sharing rates between simulated and real relatives and find that the combination of sex-specific maps and interference modeling most accurately captures IBD rates in real data. Ped-sim is open source and available from https://github.com/williamslab/ped-sim