AN EMPIRICAL STUDY INTO THE ACCURACY OF IT ESTIMATIONS AND ITS INFLUENCING FACTORS

2013 ◽  
Vol 23 (04) ◽  
pp. 409-432 ◽  
Author(s):  
A. H. ZAPATA ◽  
M. R. V. CHAUDRON
Keyword(s):  
Estimation Error ◽  
Software Project ◽  
Learning Improvement ◽  
Current Estimation ◽  
It Department ◽  
Improvement Effect ◽  
Different Dimensions ◽  
Effectiveness And Efficiency ◽  
Process Complexity ◽  
Over Time

This paper is the result of two related studies done on the estimation of IT projects at a large Dutch multinational company. The first one is a study about the accuracy of different dimensions of IT project estimating: schedule, budget and effort. [Note: This paper is an extension of the paper published by the authors as "An analysis of accuracy and learning in software project estimating" [28].] This study is based on a dataset of 171 projects collected at the IT department of the company. We analyzed the estimation error of budget, effort and schedule. Also, we analyzed whether there is any learning (improvement) effect over time. With the results of the first study we proceeded to research what is causing the current estimation error (inaccuracy). The results of our first study show that there is no relation between accuracy of budget, schedule and effort in the company analyzed. Besides, they show that over time there is no change in the inaccuracy (effectiveness and efficiency of the estimates). In our second study we discovered that the sources of this inaccuracy are: (IT estimation) process complexity, misuse of estimates, technical complexity, requirements redefinition and business domain instability. This paper reflects and provides recommendations on how to improve the learning from historical estimates and how to manage the diverse sources of inaccuracy inside this particular company and also in other organizations.

In the eye of the recipient

2014 ◽  
Vol 4 (2) ◽  
pp. 211-232 ◽  
Author(s):  
Katrin Riese ◽  
Mareike Bayer ◽  
Gerhard Lauer ◽  
Annekathrin Schacht
Keyword(s):  
Pupil Diameter ◽  
Methodological Approach ◽  
Narrative Fiction ◽  
Data Analyses ◽  
Different Dimensions ◽  
Literary Classics ◽  
The 19Th Century ◽  
Physiological Indicator ◽  
Over Time ◽  
Cognitive Dimensions

Plot suspense is one of the most important components of narrative fiction that motivate recipients to follow fictional characters through their worlds. The present study investigates the dynamic development of narrative suspense in excerpts of literary classics from the 19th century in a multi-methodological approach. For two texts, differing in suspense as judged by a large independent sample, we collected (a) data from questionnaires, indicating different affective and cognitive dimensions of receptive engagement, (b) continuous ratings of suspense during text reception from both experts and lay recipients, and (c) registration of pupil diameter as a physiological indicator of changes in emotional arousal and attention during reception. Data analyses confirmed differences between the two texts at different dimensions of receptive engagement and, importantly, revealed significant correlations of pupil diameter and the course of suspense over time. Our findings demonstrate that changes of the pupil diameter provide a reliable ‘online’ indicator of suspense.

scholarly journals Proposed T-Model to cover 4S quality metrics based on empirical study of root cause of software failures

2019 ◽  
Vol 9 (2) ◽  
pp. 1122
Author(s):  
Dheeraj Chhillar ◽  
Kalpana Sharma
Keyword(s):  
Software Development ◽  
New Technologies ◽  
Software Project ◽  
Functional Requirements ◽  
Software Failures ◽  
Root Cause ◽  
Software Development Model ◽  
Software Development Methodologies ◽  
And Performance ◽  
Over Time

<span>There are various root causes of software failures. Few years ago, software used to fail mainly due to functionality related bugs. That used to happen due to requirement misunderstanding, code issues and lack of functional testing. A lot of work has been done in past on this and software engineering has matured over time, due to which software’s hardly fail due to functionality related bugs. To understand the most recent failures, we had to understand the recent software development methodologies and technologies. In this paper we have discussed background of technologies and testing progression over time. A survey of more than 50 senior IT professionals was done to understand root cause of their software project failures. It was found that most of the softwares fail due to lack of testing of non-functional parameters these days. A lot of research was also done to find most recent and most severe software failures. Our study reveals that main reason of software failures these days is lack of testing of non-functional requirements. Security and Performance parameters mainly constitute non-functional requirements of software. It has become more challenging these days due to lots of development in the field of new technologies like Internet of things (IoT), Cloud of things (CoT), Artificial Intelligence, Machine learning, robotics and excessive use of mobile and technology in everything by masses. Finally, we proposed a software development model called as T-model to ensure breadth and depth of software is considered while designing and testing of software. </span>

Social Issues in IT Project Teams

2018 ◽  
pp. 777-787
Author(s):  
Awie C. Leonard ◽  
D. H. Van Zyl
Keyword(s):  
Social Relationships ◽  
Social Issues ◽  
Negative Impact ◽  
Project Teams ◽  
Software Project ◽  
Team Members ◽  
Project Environment ◽  
Team Environment ◽  
It Project ◽  
It Department

The role and impact of social issues in IT project teams should not be under estimated. With the involvement of virtual project teams, this is even more relevant. One such social issue is the establishment of relationships between members of teams. The establishment and maintenance of social relationships and networks in the IT project environment is a phenomenon all IT professionals are exposed to and in many cases involved in. The question is what impact such social relationships and networks might have on the success or failure of any given IT project? The objective of this chapter is therefore to emphasize the important role social relationships and networks play in the IT project team environment. Furthermore, to illustrate to the management of software project teams how such relationships can have a positive or negative impact on team members. In this regard a climate or culture should be allowed for these relationships to flourish to the benefit of the IT department.

Proportional Integral Estimator of the Stator Resistance for Direct Torque Control Induction Motor Drive

2017 ◽  
Vol 8 (4) ◽  
pp. 1631
Author(s):  
Jagdish Gangadharrao Chaudhari ◽  
Sanjay Bhauraoji Bodkhe ◽  
Mohan V. Aware
Keyword(s):  
Induction Motor ◽  
Estimation Error ◽  
Direct Torque Control ◽  
Estimation Method ◽  
Operating Conditions ◽  
Torque Control ◽  
Proportional Integral ◽  
Stator Current ◽  
Current Estimation ◽  
Stator Resistance

In this paper, an improved proportional integral stator resistance estimation for a direct torque controlled induction motor is proposed. This estimation method is based on an on-line stator resistance correction regarding the variations of the stator current estimation error. In fact, the input variable of the PI estimator is the stator current estimation error. The main idea is to tune accurately the stator resistance value relatively to the evolution of the stator current estimation error gradient to avoid the drive instability and ensure the tracking of the actual value of the stator resistance. But there is an unavoidable steady state error between the filtered stator current modulus and its estimated value from the dq model of the machine which is due to pseudo random commutations of the inverter switches. An offset has been introduced in order to overcome this problem, for different speed command values and load torques. Simulation results show that the proposed estimator was able to successfully track the actual value of the stator resistance for different operating conditions

scholarly journals Desempenho Fora-da-Amostra da Otimização Robusta de Carteiras

2010 ◽  
Vol 8 (2) ◽  
pp. 141 ◽  
Author(s):  
André Alves Portela Santos
Keyword(s):  
Robust Optimization ◽  
Portfolio Optimization ◽  
Estimation Error ◽  
Simulated Data ◽  
Minimum Variance ◽  
Optimization Techniques ◽  
Practical Implementation ◽  
Out Of Sample ◽  
Portfolio Optimization Problem ◽  
Over Time

Robust optimization has been receiving increased attention in the recent few years due to the possibility of considering the problem of estimation error in the portfolio optimization problem. A question addressed so far by very few works is whether this approach is able to outperform traditional portfolio optimization techniques in terms of out-of-sample performance. Moreover, it is important to know whether this approach is able to deliver stable portfolio compositions over time, thus reducing management costs and facilitating practical implementation. We provide empirical evidence by assessing the out-of-sample performance and the stability of optimal portfolio compositions obtained with robust optimization and with traditional optimization techniques. The results indicated that, for simulated data, robust optimization performed better (both in terms of Sharpe ratios and portfolio turnover) than Markowitz's mean-variance portfolios and similarly to minimum-variance portfolios. The results for real market data indicated that the differences in risk-adjusted performance were not statistically different, but the portfolio compositions associated to robust optimization were more stable over time than traditional portfolio selection techniques.

scholarly journals Stochastic imputation for integrated transcriptome association analysis of a longitudinally measured trait

2019 ◽  
Vol 29 (4) ◽  
pp. 1167-1180 ◽  
Author(s):  
Evan L Ray ◽  
Jing Qian ◽  
Regina Brecha ◽  
Muredach P Reilly ◽  
Andrea S Foulkes
Keyword(s):  
Association Analysis ◽  
Complex Disease ◽  
Estimation Error ◽  
Penalized Regression ◽  
Error Rates ◽  
Test Statistic ◽  
Modeling Framework ◽  
Two Stage ◽  
Regression Imputation ◽  
Over Time

The mechanistic pathways linking genetic polymorphisms and complex disease traits remain largely uncharacterized. At the same time, expansive new transcriptome data resources offer unprecedented opportunity to unravel the mechanistic underpinnings of complex disease associations. Two-stage strategies involving conditioning on a single, penalized regression imputation for transcriptome association analysis have been described for cross-sectional traits. In this manuscript, we propose an alternative two-stage approach based on stochastic regression imputation that additionally incorporates error in the predictive model. Application of a bootstrap procedure offers flexibility when a closed form predictive distribution is not available. The two-stage strategy is also generalized to longitudinally measured traits, using a linear mixed effects modeling framework and a composite test statistic to evaluate whether the genetic component of gene-level expression modifies the biomarker trajectory over time. Simulations studies are performed to evaluate relative performance with respect to type-1 error rates, coverage, estimation error, and power under a range of conditions. A case study is presented to investigate the association between whole blood expression for each of five inflammasome genes with inflammatory response over time after endotoxin challenge.

Intensity control during target approach in echolocating bats;stereotypical sensori-motor behaviour in Daubenton's bats,Myotis daubentonii

2002 ◽  
Vol 205 (18) ◽  
pp. 2865-2874 ◽  
Author(s):  
Arjan Boonman ◽  
Gareth Jones
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Level ◽  
Target Strength ◽  
Motor Behaviour ◽  
Feedback Information ◽  
Intensity Control ◽  
Myotis Daubentonii ◽  
Different Dimensions ◽  
Over Time

SUMMARYWhen approaching a prey target, bats have been found to decrease the intensity of their emitted echolocation pulses, called intensity compensation. In this paper we examine whether intensity compensation in the echolocation of bats is flexible or stereotyped. We recorded the echolocation calls of Daubenton's bats (Myotis daubentonii) while the animals attacked targets of different dimensions. Myotis daubentonii reduced the peak sound pressure level emitted by about 4dB for each halving of distance,irrespective of the target presented (mealworms and two different sizes of spheres). The absolute sound pressure level emitted by the bat is not or only a little affected by target strength. Furthermore, the decrease in emitted intensity over distance shows less scatter than the same intensity over time for the last 20 cm of target approach. The bats matched the emitted intensity to target distance equally well for the spheres (aspect-invariant target strength) as for the mealworms (aspect-dependent echo strength). We therefore conclude that intensity compensation does not rely on feedback information from received intensity, but instead follows a stereotyped pattern.

Social Issues in IT Project Teams

2019 ◽  
pp. 392-404
Author(s):  
Awie C. Leonard ◽  
D. H. Van Zyl
Keyword(s):  
Social Relationships ◽  
Social Issues ◽  
Negative Impact ◽  
Project Teams ◽  
Software Project ◽  
Team Members ◽  
Project Environment ◽  
Team Environment ◽  
It Project ◽  
It Department

The role and impact of social issues in IT project teams should not be underestimated. With the involvement of virtual project teams, this is even more relevant. One such social issue is the establishment of relationships between members of teams. The establishment and maintenance of social relationships and networks in the IT project environment is a phenomenon all IT professionals are exposed to and in many cases involved in. The question is what impact such social relationships and networks might have on the success or failure of any given IT project. The objective of this chapter is therefore to emphasize the important role social relationships and networks play in the IT project team environment and furthermore, to illustrate to the management of software project teams how such relationships can have a positive or negative impact on team members. In this regard, a climate or culture should be allowed for these relationships to flourish to the benefit of the IT department.

The Impact of eXtreme Programming on Maintenance

2011 ◽  
pp. 75-92 ◽  
Author(s):  
Fabrizio Fioravanti
Keyword(s):  
Extreme Programming ◽  
Software Project ◽  
Direct Impact ◽  
Maintenance Costs ◽  
Develop Software ◽  
The Impact ◽  
Maintenance Process ◽  
Over Time ◽  
The Way

One of the emerging techniques for managing software project is eXtreme Programming (XP), which surely is changing the way in which we develop and manage software. XP is based on four values and 12 rules that explain how to develop software in an XP-compliant mode. In this chapter, all values and rules are addressed and the XP lifecycle of a project is introduced in order to guide the reader in discovering how XP can aid maintenance by keeping maintenance costs constant over time. Before drawing conclusions, the direct impact on the maintenance process due to the adoption of XP values and rules is also exploited at the end of the chapter.

Monitoring Item Performance With CUSUM Statistics in Continuous Testing

2021 ◽  
pp. 107699862199456
Author(s):  
Yi-Hsuan Lee ◽  
Charles Lewis
Keyword(s):  
Group Size ◽  
Estimation Error ◽  
Ability Estimation ◽  
Cumulative Sum ◽  
Continuous Testing ◽  
Item Parameters ◽  
Analytical Work ◽  
Educational Assessments ◽  
Over Time ◽  
Item Preknowledge

In many educational assessments, items are reused in different administrations throughout the life of the assessments. Ideally, a reused item should perform relatively similarly over time. In reality, an item may become easier with exposure, especially when item preknowledge has occurred. This article presents a novel cumulative sum procedure for detecting item preknowledge in continuous testing where data for each reused item may be obtained from small and varying sample sizes across administrations. Its performance is evaluated with simulations and analytical work. The approach is effective in detecting item preknowledge quickly with group size at least 10 and is easy to implement with varying item parameters. In addition, it is robust to the ability estimation error introduced in the simulations.

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