Statistical process control (SPC) which includes very powerful techniques used in other mature engineering disciplines for providing process control is not used by many software organizations. In software engineering domain, SPC is currently utilized only by organizations which have high maturity levels according to the process improvement models like CMM, ISO/IEC 15504 and CMMI. Guidelines and software tools to implement SPC techniques should be developed for effective use and dissemination of SPC especially for low maturity organizations. In this thesis, a software tool (SPC-AAT) which we developed to assess the suitability of software processes and metrics for SPC and use of SPC tools is presented. With SPC-AAT, we aim to ease and enhance application of SPC especially for emergent and low maturity organizations. Control charts, histograms, bar charts and pareto charts are the supported SPC tools for this purpose. We also explained the validation of the tool over two processes of a software organization in three case studies.

Six children between the ages of seven and eleven and their parents were interviewed to gather perceptions of the Clip Chart Management System. The Clip Chart system is a behavior system used in many primary classrooms where teachers move students’ clothespins up and down a chart in response to students’ behavior. Some findings from this qualitative case study are: students experienced feelings of shame and embarrassment, students compared their clips to their peers’ clips, and students labeled other students as “bad.” Some parents appreciated the consistency of behavior monitoring, but other parents felt that the system was ineffective and contributed to their child’s negative feelings about school. The findings of this study suggest the need for much more research if this method is continued to be implemented in schools.

As time passes, change occurs. With this change comes the need for surveillance. One may be a technician on an assembly line and in need of a surveillance technique to monitor the number of defective components produced. On the other hand, one may be an administrator of a hospital in need of surveillance measures to monitor the number of patient falls in the hospital or to monitor surgical outcomes to detect changes in surgical failure rates. A natural choice for on-going surveillance is the control chart; however, the chart must be constructed in a way that accommodates the situation at hand. Two scenarios involving attribute control charting are investigated here. The first scenario involves Poisson count data where the area of opportunity changes. A modified exponentially weighted moving average (EWMA) chart is proposed to accommodate the varying sample sizes. The performance of this method is compared with the performance for several competing control chart techniques and recommendations are made regarding the best preforming control chart method. This research is a result of joint work with Dr. William H. Woodall (Department of Statistics, Virginia Tech). The second scenario involves monitoring a process where items are classified into more than two categories and the results for these classifications are readily available. A multinomial cumulative sum (CUSUM) chart is proposed to monitor these types of situations. The multinomial CUSUM chart is evaluated through comparisons of performance with competing control chart methods. This research is a result of joint work with Mr. Lee J. Wells (Grado Department of Industrial and Systems Engineering, Virginia Tech) and Dr. William H. Woodall (Department of Statistics, Virginia Tech). / Ph. D.

Die vorliegende Schulung ist vorrangig zum Selbststudium für blinde und sehbehinderte Menschen konzipiert. Neben Grundlagen und Prinzipien der taktilen Grafikerkundung werden effektive Strategien zur systematischen Erkundung taktiler Grafiken anhand konkreter Beispiele (Säulen-, Punkt- und Liniendiagramme) vorgestellt. Interessierte sehende Personen können die Informationen ebenso verwenden – einerseits um den Umgang blinder Leser und Leserinnen mit taktilen Grafiken besser zu verstehen, andererseits können Sie die Materialien auch als Grundlage verwenden, um selber blinde bzw. sehbehinderte Menschen zu schulen.:1 Einleitung 2 Grundlagen und Prinzipien der taktilen Grafikerkundung 2.1 Was ist eine taktile Grafik? 2.2 Welche Eigenschaften besitzt eine taktile Grafik? 2.3 Welche Grafiktypen gibt es? 2.4 Auf welchen Prinzipien basiert die taktile Erkundung? 3 Effektive Strategien zur Erkundung 3.1 Schritt 1 - Bildbeschreibung lesen 3.2 Schritt 2 - Einen ersten Überblick erhalten 3.3 Schritt 3 - Details erkunden 4 Anwendung der Strategien anhand konkreter Beispiele 4.1 Erkundung eines Säulendiagramms 4.2 Erkundung eines Punktdiagramms 4.3 Erkundung eines Liniendiagramms 5 Zusammenfassung

Statistical process control (SPC) is a collection of scientific tools developed and engineered to diagnose unnecessary variation in the output of a production process and eliminate it or perhaps accommodate it by adjusting process settings. The task of quality control (QC) is of fundamental importance in manufacturing processes when a change in the process causes misleading results, this alteration should be detected and corrected as soon as possible. Statistical QC charts originated in the late 1920s by Dr. W. A. Shewhart provide a powerful tool for monitoring production lines in manufacturing industries. They are also have been implemented in various disciplines, such as sequential monitoring of internet traffic flows, health care systems, and more. Shewhart-type charts are effective in detecting large shifts in the process but ineffective in detecting small to moderate shifts. This blind spot allows small shifts (smaller than one standard deviation) to continue undetected in the process, thereby incurring larger total costs for manufacturers. This thesis addresses this issue by augmenting current time-weighted charts (charts that use all the information from the start of a process until the most recent sample/observation) with a Double Generally Weighted Moving Average (DGWMA) chart, leading to more effective process monitoring. The objective of this thesis is to provide the fundamentals and introduce the researcher/practitioner to the essentials of the univariate DGWMA chart from both parametric and nonparametric perspectives. Numerous concepts and characteristics of proposed DGWMA charts are discussed comprehensively. Theoretical expressions and detailed calculations have been provided to aid the interested reader to familiarize and study the topic more thoroughly. This thesis paints a bigger picture of the DGWMA chart in a sense that other time-weighted charts such as the Generally Weighted Moving Average (GWMA), Exponentially Weighted Moving Average (EWMA), Double Exponentially Weighted Moving Average (DEWMA) and Cumulative Sum (CUSUM) fall under this umbrella. Both real-life data and simulated examples have been embedded throughout the thesis. We make use of R and Mathematica software packages to calculate numerical results related to the run length distribution and its associated characteristics in this thesis. We only consider control charts for monitoring the process location parameter. However, our conclusions and recommendations are extendable for the process dispersion parameter. In this thesis, we consider the DGWMA chart as the main chart and the EWMA, DEWMA, GWMA, and CUSUM charts as special cases. The thesis consists of the following chapters with a short description for each chapter as follows: Chapter 1 provides a brief introduction to SPC concepts and gives a literature review in terms of background information for the research conducted in this thesis. The scope and objectives of the present research are highlighted in detail. Chapter 2 provides an overview and a theoretical background on the design and implementation of the DGWMA chart derived from the SPC literature review. The properties of the DGWMA chart, including the plotting statistic, the structure for the weights, the control limits (exact/steady-state), etc. are considered in detail. The weighting structure of the DGWMA chart and its special case are discussed and pictured to emphasize the impact of weights in increasing the detection capability of time-weighted charts. Three approaches are described and investigated for calculating the run length distribution and its associated characteristics for the DGWMA chart and its special case the DEWMA chart; this includes: (i) exact approach; (ii) Markov chain approach; (iii) Monte Carlo simulation. In Chapter 3 we develop a one-sided generalized parametric chart (denoted by DGWMA-TBE) for monitoring the time between events (TBE) of nonconformities items originating from the high-yield processes when the underlying process distribution is gamma and the parameter of interest is known (Case K) and unknown (Case U). A Markov chain approach is implemented to derive the run length distribution and its associated characteristics for the DGWMA and DEWMA charts. An exact approach is also used to derive closed-form expressions for the run length distribution of the proposed chart. Performance analysis has been undertaken to execute a comparative study with several existing time-weighted charts. The proposed chart encompasses one-sided GWMA-TBE, EWMA-TBE, DEWMA-TBE, and Shewhart-type charts as limiting or special cases. The CUSUM-TBE chart is also included in the performance comparison. The necessary design parameters are provided to aid the implementation of the proposed chart and finding the optimal design and near optima design that is useful for practitioners. Alternative discrete distributions are considered for the weights of the GWMA-TBE chart and a discussion is provided to address the connection between new weights originating from the suggested distributions and the chart’s capability in detecting shifts. As a result, one can design an optimal GWMA-TBE chart by replacing weights from the discrete Weibull distribution without the implementation of the double exponential smoothing technique. Chapter 4 focuses on developing a two-sided nonparametric (distribution-free) DGWMA control chart based on the exceedance (EX) statistic, denoted as DGWMA-EX when the parameter of interest is unknown (Case U) and the underlying process distribution is continuous and symmetric. An exact approach and a Markov chain approach are considered to calculate the run length distribution and its associated characteristics for the proposed chart. A performance comparison has been undertaken to execute analysis with other nonparametric time-weighted charts available in the SPC literature. The proposed chart en-compasses two-sided GWMA-EX, EWMA-EX, DEWMA-EX, and Shewhart-type charts as limiting or special cases. The CUSUM-EX chart is also included in the performance comparison Also, the performance of the proposed DGWMA-EX chart has been evaluated under different symmetric and skewed distributions in comparison with its main counterparts, and the necessary results and recommendations are provided for practitioners to design an optimal chart. Chapter 5 encloses this thesis with a summary of the research conducted and provides concluding remarks concerning future research opportunities. / Thesis (PhD (Mathematical Statistics))--University of Pretoria, 2020. / This research was supported in part by the National Research Foundation (NRF) under Grant Number 71199 and the postgraduate research bursary supported by the University of Pretoria. Any findings, opinions, and conclusions expressed in this thesis are those of the author and do not necessarily reflect the views of the parties. / Statistics / PhD (Mathematical Statistics) / Unrestricted

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Telemetry recorders have historically been used as standalone systems with each user responsible for operation and data interpretation on that system. Utilizing the latest peerto- peer networking technologies, telemetry recorders can now be linked to provide instantaneous communication between systems. This fully distributed, network-based architecture can be used for command and control of multiple recorders, as well as message passing between them. A centralized server is no longer required, resulting in considerable logistical and cost savings. The peer-to-peer communication topology can efficiently connect telemetry recorder “islands of information”.

ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / Migrating analog architectures and equipments to network architectures is underway all across the globe. There is no doubt, a modern instrument must fit the network environment or simply will not be procured. Yet, funding constraints temper wholesale changes to net-centric technologies. The last analog stronghold in our data center is the oscillograph. Over 50 Gould TA 6000 Oscillographs reside at White Sands Missile Range. These are digital implementations of analog recorders, hence require analog signaling. Digital telemetry data (most common format) must be converted to analog to drive an oscillograph that converts analog back to digital to plot the data. The oscillograph’s interface board may be “hacked” by removing the Analog to Digital Converter (ADC) gaining direct access to the digital signal path. This idea was worth attempting as the prospect of replacing that many recorders with the newer network driven oscillographs is costly hence remote. This paper’s topic is the conversion of the hardware and a discussion on software issues. Though not pretty, it does preserve the large recorder investment for the time being. Issues with analog signaling, such as noise, drift and ground loops are gone. A commercial ethernet to digital adapter drives the new digital interface and transforms the recorder into an net-centric instrument.

International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, California / Video tape is becoming more and more popular for storing and analyzing missions. Video tape is inexpensive, it can hold a two hour test, and it can be edited and manipulated by easily available consumer electronics equipment. Standard technology allows each frame to be time stamped with SMPTE code, so that any point in the mission can be displayed on a CRT. To further correlate data from multiple acquisition systems, the SMPTE code can be derived from IRIG using commercially available code converters. Unfortunately, acquiring and storing analog data has not been so easy. Typically, analog signals from various sensors are coded, transmitted, decoded and sent to a chart recorder. Since chart recorders cannot normally store an entire mission internally, or time stamp each data value, it is very difficult for an analyst to accurately correlate analog data to an individual video frame. Normally the only method is to note the time stamp on the video frame and unroll the chart to the appropriate second or minute, depending on the code used, noted in the margin, and estimate the frame location as a percentage of the time code period. This is very inconvenient if the telemetrist is trying to establish an on-line data retreival system. To make matters worse, the methods of presentation are very different, chart paper as opposed to a CRT, and require the analyst to shift focus constantly. For these reasons, many telemetry stations do not currently have a workable plan to integrate analog and video subsystems even though it is now generally agreed that such integration is ultimately desirable.

International Telemetering Conference Proceedings / October 17-20, 1988 / Riviera Hotel, Las Vegas, Nevada / Mission safety and cost-efficiency concerns have resulted in a resurgence of interest in real-time strip chart recorders. But conventional recorder technologies require inordinate maintenance and daily calibration. Attempts at strip chart emulation involving costly dedicated microcomputers and CRT's have failed, because the chart itself is not real-time, a basic requirement. The concept of an inexpensive, direct digital link to a telemetry processing computer (VAX, e.g.) is discussed. A thorough examination of real-time monitoring of critical, non-repeatable data is presented. Objectives: An automated, turn-key telemetry data system. Reduce the routine maintenance required by conventional recording systems; eliminate the need for digital-to-analog converters (DAC's); and improve the efficiency of range personnel and the integrity of recorded data.

International Telemetering Conference Proceedings / November 04-07, 1991 / Riviera Hotel and Convention Center, Las Vegas, Nevada / A synopsis of the very recent evolution of telemetry chart recorders from “closed” chart paper output devices to powerful “open” Data Management Systems. A Data Management System (DMS) is defined as one which incorporates a video screen for waveform preview and monitoring, direct connection of hard or optical disk via SCSI for real-time data archiving, and DR11 digital interfacing. The DMS concept of providing real-time waveform monitoring independent of hard copy recording is discussed, as well as the capabilities of the hard copy recorder. The realities of budget shortfalls makes wholesale system upgrades to eliminate DAC’s entirely difficult at best. These concerns—and a potential remedy: a DMS which accepts any mix of analog and digital waveforms—are reviewed. Objectives: How DMS’s can be integrated with existing telemetry systems, encompass the functionality of conventional recorders and add new capabilities, with an emphasis on how data can be digitally pre-formatted in real-time, simplifying—or even eliminating—post-mission reduction and analysis. A demonstration of how a video display allows real-time trace viewing—a major weakness of conventional thermal array recorders.