Total Number Of Defects Research Articles

Insight Into the Mechanism of Tail Bits in Data Retention of Vacancy-Modulated Conductive Oxide RRAM

The underlying mechanism causing tail bits in data retention for high resistance state (HRS) of vacancy-modulated conductive oxide resistive RAM, consisting of TiN/amorphous-Si/TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /TiN structure, was investigated. The tail bits observed in the small size cells with large On/Off ratio were attributed to the current fluctuations in time. The mechanism, in which the current fluctuation is caused by the fragility of the conduction path in a high resistive region determining the cell current in TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , was clarified by retention measurement with various conditions of On/Off ratio and cell size. It was found that the total number of defects in the high resistive region is the key to ensure a steady HRS conduction. We, furthermore, demonstrated a way to suppress the tail bits in the small size cells (40 ×40 nm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) even with large On/Off ratio (×10 ) by process tuning of TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> film fabrication.

Detection of defective printed circuit boards using image processing

Manufacturing of printed circuit boards involves three stages (printing, component fabrication over surface of printed circuit boards, soldering of components), where inspection at every stage is very important to improve the quality of production. Image subtraction method is widely used for finding the difference between any two images. Using this method, defects have been detected by finding the difference between reference (defect free) and test image (to be inspected). The major limitation of image subtraction is that both the images should have same size and same orientation. The proposed method removes the above explained limitation of image subtraction method and also calculates total number of defects on printed circuit boards. The proposed method is tested on six test images. The experimental results show that proposed method is simple, economical and easy to implement in small and medium scale industries where most of the inspection is still done by humans.

The ISBSG Software Project Repository: An Analysis from Six Sigma Measurement Perspective for Software Defect Estimation

The International Software Benchmarking Standards Group (ISBSG) provides to researchers and practitioners a repository of software projects’ data that has been used to date mostly for benchmarking and project estimation purposes, but rarely for software defects analysis. Sigma, in statistics, measures how far a process deviates from its goal. Six Sigma focuses on reducing variations within processes, because such variations may lead to an inconsistency in achieving projects’ specifications which represent “defects”, which mean not meeting customers’ satisfaction. Six Sigma provides two methodologies to solve organizations’ problems: “Define-Measure-Analyze-Improve-Control” process cycle (DMAIC) and Design of Six Sigma (DFSS). The DMAIC focuses on improving the existed processes, while the DFSS focuses on redesigning the existing processes and developing new processes. This paper presents an approach to provide an analysis of ISBSG repository based on Six Sigma measurements. It investigates the use of the ISBSG data repository with some of the related Six Sigma measurement aspects, including Sigma defect measurement and software defect estimation. This study presents the dataset preparation consisting of two levels of data preparations, and then analyzed the quality-related data fields in the ISBSG MS-Excel data extract (Release 12 - 2013). It also presents an analysis of the extracted dataset of software projects. This study has found that the ISBSG MS-Excel data extract has a high ratio of missing data within the data fields of “Total Number of Defects” variable, which represents a serious challenge when the ISBSG dataset is being used for software defect estimation.

Defect production in Ar irradiated graphene membranes under different initial applied strains

Irradiation with low energy Ar ions of graphene membranes gives rise to changes in the mechanical properties of this material. These changes have been associated to the production of defects, mostly isolated vacancies. However, the initial state of the graphene membrane can also affect its mechanical response. Using molecular dynamics simulations we have studied defect production in graphene membranes irradiated with 140eV Ar ions up to a dose of 0.075×1014ions/cm2 and different initial strains, from −0.25% (compressive strain) to 0.25% (tensile strain). For all strains, the number of defects increases linearly with dose with a defect production of about 80% (80 defects every 100ions). Defects are mostly single vacancies and di-vacancies, although some higher order clusters are also observed. Two different types of di-vacancies have been identified, the most common one being two vacancies at first nearest neighbours distance. Differences in the total number of defects with the applied strain are observed which is related to the production of a higher number of di-vacancies under compressive strain compared to tensile strain. We attribute this effect to the larger out-of-plane deformations of compressed samples that could favor the production of defects in closer proximity to others.

Microstructure and Mechanical Properties of a 18Kt 5N Gold Alloy After Different Heat Treatments

In precious metals industry, heat treatments play a key role in the production process, since the type and the sequence of these treatments produce the right combination of hardness and workability. The production sequence usually involves rolling, plastic deformation, heat treating, and surface finishing. In this work, different heat treatments were performed on samples of 18Kt 5N gold–copper–silver alloy, and the evolution of the microstructure and the microindentation hardness was analyzed. The heat treatments were performed after the first and the second rolling process (a softening heat treatment) and before the final surface brushing and polishing (a hardening heat treatment). Two different softening heat treatments were tested: a continuous annealing treatment performed in a belt furnace and a solution heat treatment in static furnace. Two different hardening treatments were studied: an aging heat treatment and a treatment of solubilization followed by an aging treatment. The microstructural observation and mechanical analysis showed that the solution treatment in static furnace produced smaller and more homogeneous grain size than a continuous annealing treatment, whereas the hardness was not reduced. This could be very important because the reduction in the grain size results in a marked decrease in the orange peel defects on the final products. It was also found that between the two hardening treatments, solubilization and aging produced an increase of about 90 HV in the hardness with a significant reduction in the number of superficial defects during the final surface finishing steps. The optimization of the heat treatments, studied in this work, produces a significant decrease in the total number of defects at the end of the production cycle.

PENILAIAN PRESTASI BANGUNAN: ANALISIS RUANG TANDAS ASRAMA PELAJAR

Toilet with numerous functional defects will impose a sense of inconvenience to users. This paper reports on a study carried out on toilets’ condition in a government run students residential hostel for real estate. The students were housed in four (4) 10 storey blocks with two (2) blocks allocated to male and two (2) blocks to female students with toilets centralised on each floor. The four (4) blocks were built at the same time with identical design, supervised by a group of consultants and built by the same contractors. A total of 1,644 defects were recorded. This paper reveals a relationship between total number of defects with each level of floor. The defects relationship suggest, number of defects rises as one ascends the higher floors. Secondly, there is relationship on number of defects with floor level clusters and gender of the users. Total defects in the male block toilets record a higher correlation as compared to blocks utilise by female users. This findings can be used by the management of the training institute to focus maintenance work and budget to blocks and floors which have more defects.

Key Software Metrics and its Impact on each other for Software Development Projects

&lt;p class="MsoNormal" style="margin: 0in 0in 10pt; text-align: justify;"&gt;&lt;span style="line-height: 115%; font-size: 9pt; mso-bidi-font-size: 12.0pt;"&gt;&lt;span style="font-family: Calibri;"&gt;&lt;span style="mso-spacerun: yes;"&gt;&lt;span style="font-size: small;"&gt;&lt;span style="line-height: 115%; mso-bidi-font-size: 12.0pt;"&gt;Every software development project is unique and different from repeatable manufacturing process. Each software project share different challenges related to technology, people and timelines. If every project is unique, how project manager can estimate project in a consistent way by applying his past experience. One of the major challenges faced by the project manager is to identify the key software metrics to control and monitor the project execution. Each software development project may be unique but share some common metric that can be used to control and monitor the project execution. These metrics are software size, effort, project duration and productivity. These metrics tells project manager about what to deliver (size), how it was delivered in past (productivity) and how long will it take to deliver with current team capability (time and effort). In this paper, we explain the relationship among these key metrics and how they statistically impact each other. These relationships have been derived based on the data published in book “Practical Software Estimation” by International Software Benchmarking Group. This paper also explains how these metrics can be used in predicting the total number of defects. Study suggests that out of the four key software metrics software size significantly impact the other three metrics (project effort, duration and productivity). Productivity does not significantly depend on the software size but it represents the nonlinear relationship with software size and maximum team size, hence, it is recommended not to have a very big team size as it might impact the overall productivity. Total project duration only depends on the software size and it does not depend on the maximum team size. It implies that we cannot reduce project duration by increasing the team size. This fact is contrary to the perception that we can reduce the project duration by increasing the project team size. We can conclude that software size is the important metrics and a significant effort must be put during project initiation phases to estimate the project size. As software size will help in estimating the project duration and project efforts so error in estimating the software size will have significant impact on the accuracy of project duration and effort. All these key metrics must be re-calibrated during the project development life cycle. &lt;/span&gt;&lt;strong style="mso-bidi-font-weight: normal;"&gt;&lt;/strong&gt;&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;&lt;p class="MsoNormal" style="margin: 0in 0in 10pt; text-align: justify;"&gt; &lt;/p&gt;

Testing of a Covered Conductor’s Fault Detectors

The majority of medium-voltage overhead lines are currently operated with AlFe conductors which have a simple construction and which rank among the cheapest versions of overhead lines from the point of view of initial investments. These overhead lines can be susceptible, however, to faults primarily in mountain and wooded areas, with an ensuing decrease in safety and operations reliability, as well as with limitations to the electric power supply. This draws attention to outdoor overhead lines with covered conductors, which are relied upon for use for connecting “defined” systems (SMART GRIDS) with an external electric power system. These conductors, with mostly XLPE and PE basic insulation, are able to resist both mechanical and electric strain caused by falling trees or branches and consequently their total number of faults is significantly lower. Massive usage of overhead lines with covered conductors is currently contradicted by prevailing difficulties in detecting faults. This article describes the possibility of detecting covered conductor faults and verifying the methodology under both laboratory and real conditions.

Estimation of Testing and Rework Efforts for Software Development Projects

In the planning of a software development project, a major challenge faced by project managers is to predict the rework effort. (Rework effort is the effort required to fix the software defects identified during system testing). The project manager’s objective is to deliver the software within the time, cost and quality requirements given by the client. To ensure the quality of the software, many testing cycles will be conducted before it is finally delivered to the client for acceptance. Each testing cycle is a costly affair as it involves running all possible test scenarios in all possible environments, followed by defect fixing and re-verification of defects. On average, two to three testing cycles are conducted but this depends on the number of defects identified during testing. The number of defects will depend on the team expertise and whether they earlier worked on similar projects and technologies. Therefore, it becomes critical to predict the number of defects that will be identified during testing and it is a very challenging task as it requires a good model to predict the rework effort. In this paper, we describe the relationship among software size, number of software defects, productivity and efforts for software development projects. This relationship is established by using the multiple linear regression technique on the benchmarking data published by International Software Benchmarking Standard Group. There are 2 linear regression equation established one for web-based project and other for non-web-based projects. Results suggest that the web based projects are delivered faster, however, in web-based projects if we assume higher productivity higher number of defects will be found. Lower productivity will lead to fewer defects found and hence less testing and rework effort will be required therefor if we spend more development time to develop unit size than total number of defects will get reduced and will directly contribute in reducing the rework efforts. For non-web-based projects, results suggest that lower productivity will led to the more number of defects so non-web based project should be planned with much experience resources (higher productivity) so that we should have less defect and rework. Executing non-web based project with experience team require less time for development and most of the defect can be identified during unit testing and this will directly contribute in reducing the rework efforts. We infer from the relationship that software size has much significant impact on total number of defect in comparison to efforts. We also infer that while planning the software project we should use appropriate tools to reduce the margin of error in size estimation and we should also re-estimate the size, after every phase of the development life cycle to re-calibrate overall efforts and to minimize the impact on the project plan.

Research on Software Fault Distribution for Web Application

This paper studies multiple software faultdistribution model, then extends the ideas of software fault estimation based on the analysis of a large number of projectfault data.Itpresents the estimation model of software faultsdistribution for Web Application, which refers to the G-O model and Rayleigh model. Thispaper fits the faultprediction model and showsthe steps to determine the relevant parameters.Firstly, estimating the probability of finding a faultaccording to similar project data.Then estimating the total number offaults. Software fault estimation model has certain directive significance to the prediction and planning projects.Experiments show that the model has great potential to predictsoftware fault. DOI : http://dx.doi.org/10.11591/telkomnika.v12i5.5116

Bone substitutes and implantation depths for subchondral bone repair in osteochondral defects of porcine knee joints.

The purpose of this study was to identify the optimal material and implantation method for subchondral bone repair. Four osteochondral defects in a femoral groove were created in both knees of 12 pigs, and the total number of defects was 96. Eight defects were left empty (empty group). Beta-tricalcium phosphate (β-TCP) bone substitutes with 75 and 67 % porosity were implanted in 30 and 29 defects, respectively (β-TCP75 and β-TCP67 groups). Hydroxyapatite (HA) bone substitutes with 75 % porosity were filled in 29 defects (HA group). Bone substitutes were implanted at 0, 2, or 4 mm below the subchondral bone plate (SBP). The reparative tissue was assessed using microfocus computed tomography and histology 3 months after implantation. Regardless of the kind of bone substitutes, the defects were filled almost completely after implanting them at the level of the SBP, while the defects remained after implanting them at 2 or 4 mm below the SBP. Reparative tissue of the β-TCP75 group was similar to the normal cancellous bone, while that of the β-TCP67 or HA group was not. Subchondral bone defects were filled almost completely only when bone substitutes were implanted at the level of the SBP. The reparative tissue after implanting the β-TCP bone substitutes with 75 % porosity was the most similar to the normal cancellous bone. Therefore, implanting the β-TCP bone substitutes with 75 % porosity at the level of the SBP could be recommended as a treatment method for subchondral bone repair in osteochondral defects. I.

Application of Six Sigma DMAIC Methodology in Welding Assembly Quality Improvement

During the welding assembly process of automotive exhaust system, several welding defects will occur if the process parameters are incorrect, which affects the quality of products seriously. Six Sigma quality management is an advanced methodology for reducing the manufacturing costs, shortening the production cycle, and improving the product quality significantly. In this paper, the Six Sigma DMAIC method is applied to control the welding assembly process of automobile exhaust system. It is observed that the biting edge and stomata are the two main weld defects accounting about 85% of the total number of defects. In order to reduce the number of biting edge, causal diagram is used for analyzing the factors influencing the welding process. After the experiment, it is convinced that the process parameters of welding torch angle, welding speed and argon flow are the key factors affecting the biting edge significantly. Then, the optimum process parameters are determined by means of the DOE method, and the control chart is adopted to monitor the effect of process improvement. The results show that defects per million opportunities (DPMO) of biting edge could be controlled less than 1500 which is better than the target number of 5000. It is also proved that the Six Sigma DMAIC methodology is efficiently. Therefore, the stomata defects are reduced in the same way, the level of product quality is raised from 3.55σ to 4.52σ, and the competitiveness of the enterprise would be enhanced greatly.

Molecular dynamics simulations of irradiation cascades in alpha-zirconium under macroscopic strain

Numerous computer simulation studies have been performed on the radiation damage of zirconium. In contrast to most of the work in the literature which has focused on the effects of temperature and recoil energy on defect production and defect clustering, we have developed a computational model to consider the influence of elastic strain field on the formation of defects and their clusters, as strain is commonly present in a real reactor environment. In this work, irradiation induced displacement cascades in alpha-zirconium experiencing a macroscopic strain have been studied by molecular dynamics (MD) simulations using a many-body interatomic potential. The external strain mainly affects the size of defect clusters rather than the total number of defects. The sizes of interstitial and vacancy clusters respond differently to the external strain conditions.

A Combined Approach of Software Metrics and Software Fault Analysis to Estimate Software Reliability

This paper presents a fault prediction model using reliability relevant software metrics and fuzzy inference system. For this a new approach is discussed to develop fuzzy profile of software metrics which are more relevant for software fault prediction. The proposed model predicts the fault density at the end of each phase of software development using relevant software metrics. On the basis of fault density at the end of testing phase, total number of faults in the software is predicted. The model seems to useful for both software engineer as well as project manager to optimally allocate resources and achieve more reliable software within the time and cost constraints. To validate the prediction accuracy, the model results are validated using PROMISE Software Engineering Repository Data set.

Synergistic Reliability and Yield Enhancement Techniques for Embedded SRAMs

Single isolated fault (SIF) stands for about 60%-70% of the total number of defects and is rather redundancy hungry since a spare row or a column is required for repairing each SIF. Therefore, manufacturing yield will decrease if we do not allocate sufficient spare resources. In this paper, instead of the traditional fault replacement techniques, synergistic techniques that integrate both fault replacement and fault masking techniques are proposed. With our approaches, SIFs are masked instead of the traditional replacement for repairing. For other minor fault types (e.g., faulty rows and faulty columns), the fault replacement technique is used as usual. According to simulation results, repair rates can be improved significantly. The proposed techniques can be integrated with the conventional built-in self-repair with nearly negligible hardware overhead.

Unipolar resistive switching behavior of Pt/LixZn1−xO/Pt resistive random access memory devices controlled by various defect types

The unipolar resistive switching behavior of Pt/LixZn1−xO/Pt structures fabricated via radio-frequency magnetron sputtering is investigated. Various Li doping concentrations influence the defect types (i.e., VO, Lii, and LiZn) in LixZn1−xO films for adjustable resistance ratio. The resistance ratio reaches 108 due to the minimized leakage current in the high-resistance state (HRS) at 6 at. % Li dopants. The dominant conduction mechanisms are explained in terms of Ohmic behavior and Poole-Frenkel (PF) emission. The coefficient r of the PF emission in the HRS is evaluated to confirm that the total number of defects in LixZn1−xO films decreases with increasing Li content.

Evaluation of the Design Metric to Reduce the Number of Defects in Software Development

Software design is one of the most important and key activities in the system development life cycle (SDLC) phase that ensures the quality of software. Different key areas of design are very vital to be taken into consideration while designing software. Software design describes how the software system is decomposed and managed in smaller components. Object-oriented (OO) paradigm has facilitated software industry with more reliable and manageable software and its design. The quality of the software design can be measured through different metrics such as Chidamber and Kemerer (CK) design metrics, Mood Metrics & Lorenz and Kidd metrics. CK metrics is one of the oldest and most reliable metrics among all metrics available to software industry to evaluate OO design. This paper presents an evaluation of CK metrics to propose an improved CK design metrics values to reduce the defects during software design phase in software. This paper will also describe that whether a significant effect of any CK design metrics exists on total number of defects per module or not. This is achieved by conducting survey in two software development companies.

LOS MOTORES ELÉCTRICOS DE TRACCIÓN FERROVIARIA. CARACTERÍSTICAS Y TÉCNICAS DE MANTENIMIENTO DEL SISTÉMA ELÉCTRICO.

Due to their operating characteristics, continuous speed control and their reversible performance, traction motors can be considered a specific class among industrial electric motors. They are subjected to significant thermal, electrical, mechanical and environmental stresses and the increasing demand for security and reliability and the reduction of costs demand specific manufacturing requirements somehow different from other electric motors. Moreover, the development of high speed railways around the world increases the requirements on the electrical machine. These new requirements on the design and manufacturing of traction motors have a significant impact on their maintenance and repairing. Consequently, this paper deals with the requirements that a modern repair workshop must fulfill, stressing the need for personnel specialization and for the use of the most advanced technology in maintenance and repairing. Due to space limitation, the paper describes with more detail the issues related to the insulation material, since it is the motor component most stressed in operating conditions and accounts for a great percentage of the total number of faults.

PREDICCIÓN DE LA TEMPERATURA DE LA CONTENCIÓN PRIMARIA DE UNA CENTRAL NUCLEAR MEDIANTE REDES NEURONALES.

Due to their operating characteristics, continuous speed control and their reversible performance, traction motors can be considered a specific class among industrial electric motors. They are subjected to significant thermal, electrical, mechanical and environmental stresses and the increasing demand for security and reliability and the reduction of costs demand specific manufacturing requirements somehow different from other electric motors. Moreover, the development of high speed railways around the world increases the requirements on the electrical machine. These new requirements on the design and manufacturing of traction motors have a significant impact on their maintenance and repairing. Consequently, this paper deals with the requirements that a modern repair workshop must fulfill, stressing the need for personnel specialization and for the use of the most advanced technology in maintenance and repairing. Due to space limitation, the paper describes with more detail the issues related to the insulation material, since it is the motor component most stressed in operating conditions and accounts for a great percentage of the total number of faults.

Fault Prediction Model by Fuzzy Profile Development of Reliability Relevant Software Metrics

This paper presents a fault prediction model using reliability relevant software metrics and fuzzy inference system. For this a new approach is discussed to develop fuzzy profile of software metrics which are more relevant for software fault prediction. The proposed model predicts the fault density at the end of each phase of software development using relevant software metrics. On the basis of fault density at the end of testing phase, total number of faults in the software is predicted. The model seems to useful for both software engineer as well as project manager to optimally allocate resources and achieve more reliable software within the time and cost constraints. To validate the prediction accuracy, the model results are validated using PROMISE Software Engineering Repository Data set.