bluuebunny/crossref_metadata_2025 huggingface dataset:
A case study of an international e-learning training division: Meeting objectives
Authors: McGreal Rory
Published: November 2016

This paper presents an evaluation of the work of the Commonwealth of Learning’s (COL) eLearning with International Organisations (eLIO) section. Participants in the investigation included a representative sample of the learners (N = 15), their supervisors (N = 5), and the COL staff, including all of the eLIO staff (N = 10). The methodology consisted of an examination of all relevant documents, interviews that formed a learning history, and a sample survey. The investigation concluded that the eLIO achieved its goal of developing a distance learning model, and it met or exceeded identified objectives, with a high degree of satisfaction expressed by all participants. This included teaching +2000 satisfied learners; partnering with eight international organizations; achieving a 62% female participation rate and a high completion rate (75%) in the courses provided; testing, piloting, and delivering two new elearning courses; conducting needs analyses; recruiting/training highly qualified tutors; monitoring; and using appropriate technologies. Shortcomings of the programmes include the lack of pre- and post-tests, little analysis of pricing structures, some unclear instructions (a need for plain English), unclear copyright licensing, only very limited use of available OER software, and the absence of a succession plan for the manager. Based on the high level of satisfaction among all participants, it was recommended that the section maintain its present work and address these shortcomings.
Evaluation of an undergraduate physics programme of Indira Gandhi National Open University: A case study
Authors: Mishra Arundhati , Vijayshri - , Garg Suresh
Published: November 2016

The undergraduate science programme was launched at the Indira Gandhi National Open University (IGNOU) in 1991-92 with an enrolment of 1,210 students. The programme was well received, and enrolments increased over the years. However, the success rates have not kept pace with enrolment.

In this paper, the authors report the results of an evaluation of the undergraduate Physics programme at IGNOU. The evaluation, the first of its type for this programme, adapted the major tenets of the CIPP model. The findings are based on the responses from a randomly chosen sample of 509 learners across India. The methods employed for the study include records, document, and database analysis, surveys, and case studies.

Although the University has enhanced access to higher science education, the attrition rate is high (73%), and the success rate is low. The authors recommend that the University review and reorient its strategies for providing good quality, learner-centred higher education in science subjects. The programme should address the concerns of the learners about the effectiveness of the student support systems, the difficulty level, and the learner-friendliness of study materials with the goal of achieving long-term sustainability while maintaining parity with the conventional system. The need for improving the presentation of the courses and simplifying the mathematical details is emphasised.
Thirty years of distance education: Personal reflections
Authors: McKee Terralyn
Published: November 2016

This paper reflects on the evolving experience of modern distance education (DE) as a field of practice for professionals and as a medium for student access to education and training. The writer’s 30 years in the field, as both teacher and student, has coincided with the five-stage evolution of DE delivery defined by Taylor (1995-2010). The author considers the perceived identity crisis and diverse theoretical frameworks of the field since the 1980s as well as the need for new levels of change management that will enable the tools, technologies, and emerging systems of DE to create the flexibility, responsiveness, and networking that the students require and that the teachers need to learn.
The pedagogical enhancement of open education: An examination of problem-based learning
Authors: Gurell Seth , Kuo Yu-Chun , Walker Andrew
Published: November 2016

Open education, as embodied in open educational resources (OER) and OpenCourseWare (OCW), has met and dealt with several key problems. The movement now has a critical mass of available content. Leveraging no small amount of funding and associated development, open education has the tools to collect, disseminate, and support the discovery of open materials. Now that the foundation for openness has been laid, practitioners are experimenting with new kinds of education and pedagogies associated with open content (Weller, 2009; di Savoia, 2009). Problem-based learning is one of many progressive pedagogies that might be combined with open education. This paper defines problem-based learning in the context of open education. Unique challenges are presented and discussed alongside possible solutions, realistic limitations, and calls for implementation in the future to test validity.
An application of PLAR to the development of the aboriginal self: One college’s experience
Authors: Robertson Lloyd Hawkeye
Published: November 2016

Some forms of prior learning assessment and recognition (PLAR) invite self-reflection and the generation of new knowledge leading to self-growth in granting credit for past experiential learning. This paper examines the experience of a northern Canadian community college using PLAR portfolio development to assist in individual self-growth among people of aboriginal ancestry. The author reviews the theoretical underpinning behind the notion that PLAR may be used in identity construction and reviews some of the historical circumstances affecting the development of aboriginal selves. Divergent views of participants who had completed PLAR facilitator training on portfolio development are examined. Ethical concerns are raised, and guidelines are proposed for the use of PLAR in portfolio development and identity construction.
The role of language in portfolio learning
Authors: Conrad Dianne
Published: November 2016

Within the practice of recognizing prior learning (RPL), language issues –writing, the act of capturing language – are critically important facets of portfolio development. Using data drawn from a study of several postsecondary institutions in three countries, this paper examines the role and impact of language in portfolio development processes. Specifically, it considers the dynamics that contribute to learners’ finding appropriate language and their response to that journey, noting that learners pass through several stages of language growth, beginning with learning the language of academic life and recognizing the importance of that “new” language.  The paper also discusses the impact of assessors’ use of language and considers the notion of learners’ transformation as they pass through the portfolio learning process.

 
Delimiting the prospect of openness: An examination of initial student approaches to e-learning
Authors: Naughton Christopher Francis , Roder John , Smeed Juliette Emma
Published: November 2016

When converting from a paper-based distance mode to an online mode of teaching, certain expectations arise that students may engage not only in the development of extended research activity but that the quality of discussion and thinking will change. With access to open-ended discussion within the online forum the opportunity is afforded to students to share ideas and in turn develop their shared knowledge, a facility denied to them when in the paper distance mode. However, in a recent study conducted in New Zealand, it was shown that despite having access to online forums students moving to an online platform refrained from participation in this social exchange. A possible explanation for this indifference was thought to be the students realising that the online exchange made no impact on their assessment. Hence, the collaborative rhetoric of Web 2.0 made little impact when the summative evaluation remained unchanged from previous paper-based assessment. This paper reports on the introduction of online learning at a private tertiary college in New Zealand and describes the response of students who found difficulty in reconciling a community of learners and openness within what was perceived as an evaluation that remained individualistic and competitive in nature.
Three generations of distance education pedagogy
Authors: Anderson Terry , Dron Jon
Published: November 2016

This paper defines and examines three generations of distance education pedagogy. Unlike earlier classifications of distance education based on the technology used, this analysis focuses on the pedagogy that defines the learning experiences encapsulated in the learning design. The three generations of cognitive-behaviourist, social constructivist, and connectivist pedagogy are examined, using the familiar community of inquiry model (Garrison, Anderson, & Archer, 2000) with its focus on social, cognitive, and teaching presences. Although this typology of pedagogies could also be usefully applied to campus-based education, the need for and practice of openness and explicitness in distance education content and process makes the work especially relevant to distance education designers, teachers, and developers. The article concludes that high-quality distance education exploits all three generations as determined by the learning content, context, and learning expectations.
Decolonizing cyberspace: Online support for the Nunavut MEd
Authors: McAuley Alexander , Walton Fiona
Published: November 2016

Offered between 2006 and 2009 and graduating 21 Inuit candidates, the Nunavut Master of Education program was a collaborative effort made to address the erosion of Inuit leadership in the K-12 school system after the creation of Nunavut, Canada’s newest territory, in 1999. Delivered to a large extent in short, intensive, face-to-face courses, the program also made extensive use of online supports. This paper outlines the design challenges – geographical, technological, pedagogical, and cultural – that faced the development and delivery of the online portion of the program. It highlights the intersection of the design decisions with the decolonizing principles that framed the program as a whole, the various and varying roles played by the online environment over the course of the program, and the program’s contribution to student success.
"Chaos rules" revisited
Authors: Murphy David
Published: November 2016

About 20 years ago, lost in the midst of my PhD research, I mused over proposed titles. I was pretty pleased with myself to come up with ‘Chaos Rules’ (the implied double meaning was deliberate) or, more completely, Chaos Rules: An Exploration of The Work of Instructional Designers in Distance Education. I used the then emerging theories of chaos and complexity to underpin my analysis. So it was with not just a little excitement that I read the call for contributions to this Special Issue. What follows is a ‘walk through’ my thesis, with an emphasis on the contribution of chaos and complexity theory.

 
Emergent, self-directed, and self-organized learning: Literacy, numeracy, and the iPod Touch
Authors: Ricci Carlo Antonio
Published: November 2016

This paper uses narrative and storying to retell how two girls ages 5 and 7 continue to make use of an iPod touch to expand their literacy and numeracy. The paper explores the stopwatch and alarm features within the clock application, as well as the weather application, and the Internet browsing capability of the iPod touch. It also explores some of the challenges and inequities inherent in using this type of technology. The paper concludes with the author’s belief that it is important to allow learners freedom to explore and freely play with the technology and that emergent, self-directed, and self-organized learning is a natural and gentle approach to lifelong learning.

Becoming literate and numerate is infinitely complicated, yet very simple. It is infinitely complicated because there are so many variables within and without the individual who is learning these skills that understanding the process fully is nearly impossible. Yet, it is simple because so many successfully become literate and numerate so naturally. Relating to this point Schuerwegen (2011) writes,

Ergo, when a child grows up in a reading, writing, counting environment, especially an electronically driven society such as ours, he will one day find the need to pick up all these skills, at least as much as he needs them. (p. 22)

 
A needs assessment of ODL educators to determine their effective use of open educational resources
Authors: Okonkwo Charity Akuadi
Published: November 2016

Nigeria has joined the global race of teaching and learning in a changing educational environment by adopting open and distance learning (ODL). Although it is a global trend, ODL poses some challenges at local levels, one of which is the untimely production of teaching materials currently affecting instructional delivery in Nigeria. The modern approach to ameliorating this challenge is the deployment of open educational resources (OER), and this practice is enabled by information and communication technology (ICT). Hence, today’s educators need OER tools and ICT skills to address the changing nature of education. This paper assessed the needs, readiness, and willingness of ODL professionals from two dual-mode universities in Nigeria to deploy OER in teaching and learning. Data were collected using structured questionnaire items. The major findings of the study’s survey indicated that educators have not really embedded OER in teaching and learning, but they are very eager to be trained in the rudiments of OER and wish to employ them thereafter. The results indicate there is an urgent need for professional development to include training in the rudiments of OER for educators.
Searching for and positioning of contextualized learning objects
Authors: Baldiris Navarro Silvia Margarita , Graf Sabine , Fabregat Ramon , Duque Méndez Nestor Darío
Published: November 2016

Learning object economies are marketplaces for the sharing and reuse of learning objects (LO). There are many motivations for stimulating the development of the LO economy. The main reason is the possibility of providing the right content, at the right time, to the right learner according to adequate quality standards in the context of a lifelong learning process; in fact, this is also the main objective of education. However, some barriers to the development of a LO economy, such as the granularity and editability of LO, must be overcome. Furthermore, some enablers, such as learning design generation and standards usage, must be promoted in order to enhance LO economy. For this article, we introduced the integration of distributed learning object repositories (DLOR) as sources of LO that could be placed in adaptive learning designs to assist teachers’ design work. Two main issues presented as a result: how to access distributed LO, and where to place the LO in the learning design. To address these issues, we introduced two processes: LORSE, a distributed LO searching process, and LOOK, a micro context-based positioning process, respectively. Using these processes, the teachers were able to reuse LO from different sources to semi-automatically generate an adaptive learning design without leaving their virtual environment. A layered evaluation yielded good results for the process of placing learning objects from controlled learning object repositories into a learning design, and permitting educators to define different open issues that must be covered when they use uncontrolled learning object repositories for this purpose. We verified the satisfaction users had with our solution.
Looking out and looking in: Exploring a case of faculty perceptions during e-learning staff development
Authors: Esterhuizen Hendrik Daniël , Blignaut Seugnet , Ellis Suria
Published: November 2016

This explorative study captured the perceptions of faculty members new to technology enhanced learning and the longitudinal observations of the e-learning manager during dedicated professional development in order to compile a socially transformative emergent learning technology integration framework for open and distance learning at the School of Continuing Teacher Education at North-West University, South Africa. A pragmatic approach guided the bounded case study. The study followed a fully mixed sequential equal status design of mixing sequential qualitative and quantitative findings. Data collection strategies concern a custom-made questionnaire, interviews with faculty members, and longitudinal observations by the e-learning manager. The first phase uncovered 34 qualitative codes. After quantitating of the data, a t-test indicated significant differences for 17 variables between faculty perceptions and observations of the e-learning manager. Ward’s method of Euclidean distances grouped the variables into five clusters according to the researchers’ paradigm of looking in and looking out from the development context. The clusters formed the basis of a model for faculty development towards socially transformative learning technology integration for open distance learning. The five aspects of the model comprise (i) the environment in which faculty members should gain support from the institution; (ii) the environment in which faculty have to address the realities of adopting TEL; (iii) human factors relating to the adoption of TEL; (iv) concerns and reservations about the use of TEL; and (v) continuing professional development needs, expectations, and motivators. The sustainable integration of ICT into higher education institutions remains a major challenge for the adoption of TEL.
Do UOC students fit in the Net Generation profile? An approach to their habits in ICT use
Authors: Romero Marc , Guitert Montse , Sangrà Albert , Bullen Mark
Published: November 2016

Some authors have stated that university students born after 1982 have been profoundly influenced by digital technologies, showing different characteristics when compared to previous generations. However, it is worth asking if that is a current observable phenomenon. Are those students born after the 80s really more familiar with ICT tools than those born in previous generations? Do they show different study habits and learning paths? Different research lines (Kennedy, et al., 2010; Bennett, Maton, & Kervin, 2008; Gros, García, & Escofet, 2012) highlight that scientific data is rarely used when discussing this generation’s characteristics; however, none of them have proved in statistical terms that college students do not fit in the Net Generation characteristics and that their habits of ICT use in social and professional activities do not differ from older generations. The international research project, Digital Learners in Higher Education, seeks to develop a sophisticated and evidence-based understanding of university learners in different institutional contexts and the perception of cultures in their use of technology in a social and educational context. Data has been collected from four institutions in Canada and Spain: the British Columbia Institute of Technology, the University of Regina, the Open University of Catalonia (UOC), and the University Rovira i Virgili. In order to develop this project, we used a multi-case study embedded design (Yin, 2009). The UOC’s case is deeply analysed in this paper to affirm that the Net Generation is more speculative than real and that includes students’ perception about this phenomenon, and guidelines are proposed in an eLearning context.
First year chemistry laboratory courses for distance learners: Development and transfer credit acceptance
Authors: Brewer Sharon E. , Cinel Bruno , Harrison Michelle , Mohr Christina L.
Published: November 2016

In delivering chemistry courses by distance, a key challenge is to offer the learner an authentic and meaningful laboratory experience that still provides the rigour required to continue on in science. To satisfy this need, two distance general chemistry laboratory courses appropriate for Bachelor of Science (B.Sc.) students, including chemistry majors, have been recently developed at Thompson Rivers University. A constructive alignment process was employed which clearly mapped learning outcomes and activities to appropriate assessment tools. These blended laboratory courses feature custom, home experimental kits and combine elements of online and hands-on learning. The courses were designed for flexible continuous enrollment and provide online resources including tutor support, instructional videos, lab report submission, and student evaluation. The assessment of students includes laboratory reports, safety quizzes, reflective journaling, digital photo documentation, and invigilated written and online practical exams. Emphasizing the quality and rigour in these distance laboratory learning experiences allowed both courses to be accepted for B.Sc. transfer credit by other institutions, an important criterion for students. This paper will outline the design and development process of these new blended laboratory courses, their course structures and assessments, and initial student results.
Predicting POI Visits in a Heterogeneous Location-Based Social Network
Authors: Wang Zih-Syuan ,   Department of Engineering Science, National Cheng Kung University, Juang Jing-Fu , Teng Wei-Guang
Published: November 2016

A point of interest (POI) is a specific location that people may find useful or interesting, such as restaurants, stores, attractions, and hotels. With the recent proliferation of location-based social networks (LBSN), numerous users gather to interact and share information on various POIs. POI recommendations have become a crucial issue because it not only helps users to learn about new places but also gives LBSN providers chances to post POI advertisements. As we utilize a heterogeneous information network to represent an LBSN in this work, POI recommendations are remodeled as a link prediction problem, which is significant in the field of social network analysis. Moreover, we propose to utilize the meta-path-based approach to extract implicit but potentially useful relationships between a user and a POI. Then, the extracted topological features are used to construct a prediction model with appropriate data classification techniques. In our experiments, the Yelp dataset is utilized as our testbed for performance evaluation purposes. The results show that our prediction model is of good prediction quality in practical applications.
Experimental Evaluation of Cell Balancing Algorithms with Arduino Based Monitoring System
Authors: Talha Muhammad ,   School of Electronics and Information Engineering, Kunsan National University, Asghar Furqan , Kim Sung Ho ,   Department of Control and Robotics Engineering, Kunsan National University
Published: November 2016

The trend toward more electric vehicles has demanded the need for high efficiency, high voltage and long life battery systems [1,_2]. Also renewable energy systems carry huge battery backups to overcome the renewable source shortage. Battery systems are affected by many factors, cells unbalancing is one of most important among these factors. Without the balancing system, individual cell voltages will differ over time that will decrease the battery pack capacity quickly. This condition is especially severe when the battery has a long string of cells and frequent regenerative charging is done via battery pack. Cell balancing is a method of designing safer battery solutions that extends battery runtime as well as battery life. Balancing mechanism can help in equalizing the state of charge across the multiple cells, therefore increasing the performance of battery system. Different cell balancing methodologies have been proposed for battery pack in recent years. These methods have some merits and demerits in comparison to each other; e.g. balancing time, complexity and active or passive balancing etc. In this paper, current bypass active cell balancing and Arduino based monitoring system designing and implementation is carried out. In charging process, this balancing technique provides partial current bypass using charging slope for weak cells. Also the passive shunt resistor technique is implemented to compare and verify the proposed system efficient response. Output result shows that this proposed balancing technique can perform cell balancing in much effective and efficient way as compared to previous balancing techniques. Using this cell balancing technique, we can improve overall battery health and lifetime.
The Efficacy of Leader’s Islamic spiritual Intelligence Toward Employee Emotional Well-being
Authors: Hastuti Rina
Published: November 2016

The objective of this study is to find the evidence for the efficacy of Religiosity on spirituality workplace. The research conducted by measuring the effect of employee’s perspectives of leader’s islamic spiritual intelligence on employee emotional well-being which mediated by the quality of  employee spiritual value. The data was collected from the employees of moslem small medium enterprises on cullinary industry in Surakarta. The 75 samples was analyzed by multivariate analysis (Path Analysis) using SPSS 18 Software Program.The Islamic spiritual intelligence is explained by the variables that reflect the Muhammad SAW characters: sidiq (truthfulness), amanah (trustful), tabliq, and fatanah (wisdom). From the empirical research reveal that the employee spiritual value significantly mediating the effect of sidiq and fatanah toward employee’s emotional wellbeing. Meanwhile the variable of amanah and tabliq has no significant effect to employee spiritual value and employee emotional wellbeing. Therefore the higher the islamic spiritual value of leader (sidiq and fatanah) the higher the spiritual value of employee and the better the quality of employee’s emotional wellbeing. 
Field-Validated Models for Predicting Electric Submersible Pump Run Life in Saudi Fields
Authors: Qahtani Abdullah M. , Qahtani Mubarak A.
Published: November 2016

Although reliability analysis has been used for many years in different industries, the more rigorous analyses are relatively new applications in oil fields. Reliability analysis is using statistical analysis for analyzing the expected duration of time until one or more events happen. This technique is best applied in areas with single variable or changing parameter like corrosion rate. ESPs are engineered electromechanical systems having multiple components and materials. Very often, in ESP system, of multiple components and different quality; parametric analysis may not be applicable. This is due to the fact that the efficiency of an electric submersible pump system is function of the multiplied efficiencies of its components, i.e. motor, pump, seal, cable, etc. and hence this is still an area of debate in oil industry. Hence, censoring and data scrutiny, with projection of operational knowledge, would add more sense to the collected data. The use of reliability analysis for the estimation of run life of electrical submersible pump (ESP) has been sparsely applied in the oil field to predict the availability of a mechanical system such ESP. This is of a paramount importance to predict failure and plan for the availability of workover rig to replace ESP's.

This paper present the results of a comparative statistical analysis applied to evaluate the run lives of electric submersible pumps in some Saudi fields using different reliability methods. This was carried out after data scrutinizing and screening to help analyze pump performance and optimize future installations. ESP design system was used to screen out improperly designed applications.

The objective of this study was to investigate the use of statistical analyses in ESP run life calculation, identity what distribution functions best model ESP failure, estimate ESPs' run lives, identify potential improvement in ESP run life (inherent reliability vs. practical), estimate ESP replacement requirements, and compare results with ESP failure reports to explain changes in ESP life's.
Improved Sucker Rod Pumping Systems Performance by Fully Automated Closed Loop and Control Solution
Authors: Ghareeb Mohamed , Sadek Nael , Sbeih Ayham , Elfotouh Abu , Nasser Abdel
Published: November 2016

The main goal of all production operators is maximizing production and net profit out in a very safe and environmentally controlled manner. When producing difficult fluids from marginal, mature and brown onshore oil fields, Sucker rod (Beam and Progressive Cavity) Pumping systems are typically the most common artificial lift methods used. The primary challenge is to extend the lifting equipment run life, especially the downhole components. For years, operators have been looking for a reliable and accurate way to automatically control these types of lifting systems to improve their reservoir recovery factor by maximizing production.

The best-proven way for operators to make proactive decisions for well / field optimization, is to have a fully automated closed-loop monitoring and control solution for the entire field of artificially lifted wells. This paper will show how the well automation and real time downhole measurements are used in real time to control and optimize the operation parameters and well production to obtain maximum benefits. Some case histories for Beam and Progressive cavity pumping systems from different oil fields will presented.
Cable Concept Evaluation for ESP Rigless Deployment
Authors: Xiao J. J. , Roth Brian , Lastra Rafael , Aramco Saudi , Sarawaq Yahya , Mack John
Published: November 2016

This paper presents results of a comprehensive study on cable design concepts for Electric Submersible Pumping (ESP) rigless deployment. One of the key challenges faced by operators with ESPs is how to efficiently deploy and retrieve these systems. Rig-based, conventional jointed pipe installations are costly for high pressure naturally flowing wells, especially offshore. Over the years, various Cable Deployed ESP (CDESP) concepts and technologies have been proposed and tested. Most of the concepts worked to some degree but very little additional development has been done to optimize the technology. The focus of this study was to conduct state-of-the-art technology review, explore different concepts based on technological and material advancement, and identify the most viable cable design concept for further development.

All aspects of ESP deployment and retrieval have been reviewed to ensure a complete definition of the requirements and technology gaps. The cable has to perform a dual function: to conduct power efficiently and to support the downhole assembly. There are three critical aspects to the development of this cable concept: environmental protection, ability to carry the weight of downhole assembly and cable terminations. One of the key environmental requirements is to withstand 15% H2S concentration. A reliable method for isolating the conductors from H2S exposure is a key requirement. The second key requirement is that the cable needs to have ability to carry its own weight plus the weight of the ESP with additional over pull load capacity. A third key element in the design involves methods to terminate the cable with the ability to transmits power and provide mechanical support.

Several possible cable design concepts were investigated in this study: wire wrapped, copper conductor cable, non-copper conductor cable, and Slick Line Power Cable (SLPC). Taking into consideration of various requirements, it was concluded that SLPC had the most merit. It addressed the issue of H2S permeability as well as handling issues. The size and weight of the system are within reasonable limits making transportation less of an issue. There are fewer different materials used so differential thermal and mechanical force considerations are simplified and electrical and mechanical connections are more straightforward. All of these considerations lead to a development that is less risky and faster than the other options investigated.
The theoretical surrender value in life insurance
Authors: Ettore D’Ortona Nicolino , Sole Staffa Maria
Published: November 2016

In the context of the stochastic models for the management of life insurance portfolio, the authors explore, with simulation approach, the effects induced by the application of a particular method of calculation of the surrender value. In the life insurance, the policyholder position is, at any moment, quantified by the mathematical reserve. In case the reserve amount results are positive, the insurance company can allow the contract surrender, consisting in an amount payment, called surrender value, commensurate with the mathematical reserve. Generally, the insurance company enforces some restrictions in the surrender value determination, in order to avoid, first of all, that an amount is disbursed to the policyholder while, on the contrary, he results to be indebted to the Company. In this paper the authors will consider a surrender value calculation method based precisely on the profit recovery concept which shall be supplied by the contract in case it remains in the portfolio. Additionally, the authors shall analyze, by simulation approach, the effects caused by the enforcement of the surrender value calculation concept on a life portfolio profitability, and on the penalties extent enforced to the policyholders which cancel from the contract.
Keywords: surrender value, life insurance, internal risk model, stochastic simulation
Mutually Testing Processes
Authors: Bernardi Giovanni , Hennessy Matthew
Published: November 2016

In the standard testing theory of DeNicola-Hennessy one process is considered
to be a refinement of another if every test guaranteed by the former is also
guaranteed by the latter. In the domain of web services this has been recast,
with processes viewed as servers and tests as clients. In this way the standard
refinement preorder between servers is determined by their ability to satisfy
clients. But in this setting there is also a natural refinement preorder
between clients, determined by their ability to be satisfied by servers. In
more general settings where there is no distinction between clients and
servers, but all processes are peers, there is a further refinement preorder
based on the mutual satisfaction of peers. We give a uniform account of these
three preorders. In particular we give two characterisations. The first is
behavioural, in terms of traces and ready sets. The second, for finite
processes, is equational.
Permissive Controller Synthesis for Probabilistic Systems
Authors: Drager Klaus , Forejt Vojtech , Kwiatkowska Marta , Parker David , Ujma Mateusz
Published: November 2016

We propose novel controller synthesis techniques for probabilistic systems
modelled using stochastic two-player games: one player acts as a controller,
the second represents its environment, and probability is used to capture
uncertainty arising due to, for example, unreliable sensors or faulty system
components. Our aim is to generate robust controllers that are resilient to
unexpected system changes at runtime, and flexible enough to be adapted if
additional constraints need to be imposed. We develop a permissive controller
synthesis framework, which generates multi-strategies for the controller,
offering a choice of control actions to take at each time step. We formalise
the notion of permissivity using penalties, which are incurred each time a
possible control action is disallowed by a multi-strategy. Permissive
controller synthesis aims to generate a multi-strategy that minimises these
penalties, whilst guaranteeing the satisfaction of a specified system property.
We establish several key results about the optimality of multi-strategies and
the complexity of synthesising them. Then, we develop methods to perform
permissive controller synthesis using mixed integer linear programming and
illustrate their effectiveness on a selection of case studies.
Containment for Conditional Tree Patterns
Authors: Facchini Alessandro , Hirai Yoichi , Marx Maarten , Sherkhonov Evgeny
Published: November 2016

A Conditional Tree Pattern (CTP) expands an XML tree pattern with labels
attached to the descendant edges. These labels can be XML element names or
Boolean CTPs. The meaning of a descendant edge labelled by A and ending in a
node labelled by B is a path of child steps ending in a B node such that all
intermediate nodes are A nodes. In effect this expresses the until B, A holds
construction from temporal logic.This paper studies the containment problem for
CTP. For tree patterns (TP), this problem is known to be coNP-complete. We show
that it is PSPACE-complete for CTP. This increase in complexity is due to the
fact that CTP is expressive enough to encode an unrestricted form of label
negation: ${*}\setminus a$, meaning "any node except an a-node". Containment of
TP expanded with this type of negation is already PSPACE-hard. CTP is a
positive, forward, first order fragment of Regular XPath. Unlike TP, CTP
expanded with disjunction is not equivalent to unions of CTP's. Like TP, CTP is
a natural fragment to consider: CTP is closed under intersections and CTP with
disjunction is equally expressive as positive existential first order logic
expanded with the until operator.
Bounding linear head reduction and visible interaction through skeletons
Authors: Clairambault Pierre
Published: November 2016

In this paper, we study the complexity of execution in higher-order
programming languages. Our study has two facets: on the one hand we give an
upper bound to the length of interactions between bounded P-visible strategies
in Hyland-Ong game semantics. This result covers models of programming
languages with access to computational effects like non-determinism, state or
control operators, but its semantic formulation causes a loose connection to
syntax. On the other hand we give a syntactic counterpart of our semantic
study: a non-elementary upper bound to the length of the linear head reduction
sequence (a low-level notion of reduction, close to the actual implementation
of the reduction of higher-order programs by abstract machines) of simply-typed
lambda-terms. In both cases our upper bounds are proved optimal by giving
matching lower bounds. These two results, although different in scope, are
proved using the same method: we introduce a simple reduction on finite trees
of natural numbers, hereby called interaction skeletons. We study this
reduction and give upper bounds to its complexity. We then apply this study by
giving two simulation results: a semantic one measuring progress in
game-theoretic interaction via interaction skeletons, and a syntactic one
establishing a correspondence between linear head reduction of terms satisfying
a locality condition called local scope and the reduction of interaction
skeletons. This result is then generalized to arbitrary terms by a local
scopization transformation.
Detecting Unrealizability of Distributed Fault-tolerant Systems
Authors: Finkbeiner Bernd , Tentrup Leander
Published: November 2016

Writing formal specifications for distributed systems is difficult. Even
simple consistency requirements often turn out to be unrealizable because of
the complicated information flow in the distributed system: not all information
is available in every component, and information transmitted from other
components may arrive with a delay or not at all, especially in the presence of
faults. The problem of checking the distributed realizability of a temporal
specification is, in general, undecidable. Semi-algorithms for synthesis, such
as bounded synthesis, are only useful in the positive case, where they
construct an implementation for a realizable specification, but not in the
negative case: if the specification is unrealizable, the search for the
implementation never terminates. In this paper, we introduce counterexamples to
distributed realizability and present a method for the detection of such
counterexamples for specifications given in linear-time temporal logic (LTL). A
counterexample consists of a set of paths, each representing a different
sequence of inputs from the environment, such that, no matter how the
components are implemented, the specification is violated on at least one of
these paths. We present a method for finding such counterexamples both for the
classic distributed realizability problem and for the fault-tolerant
realizability problem. Our method considers, incrementally, larger and larger
sets of paths until a counterexample is found. For safety specifications in
weakly ordered architectures we obtain a decision procedure, while
counterexamples for full LTL and arbitrary architectures may consist of
infinitely many paths. Experimental results, obtained with a QBF-based
prototype implementation, show that our method finds simple errors very
quickly, and even problems with high combinatorial complexity, like the
Byzantine Generals' Problem, are tractable.
Service-Oriented Logic Programming
Authors: Tutu Ionut , Fiadeiro Jose Luiz
Published: November 2016

We develop formal foundations for notions and mechanisms needed to support
service-oriented computing. Our work builds on recent theoretical advancements
in the algebraic structures that capture the way services are orchestrated and
in the processes that formalize the discovery and binding of services to given
client applications by means of logical representations of required and
provided services. We show how the denotational and the operational semantics
specific to conventional logic programming can be generalized using the theory
of institutions to address both static and dynamic aspects of service-oriented
computing. Our results rely upon a strong analogy between the discovery of a
service that can be bound to an application and the search for a clause that
can be used for computing an answer to a query; they explore the manner in
which requests for external services can be described as service queries, and
explain how the computation of their answers can be performed through
service-oriented derivatives of unification and resolution, which characterize
the binding of services and the reconfiguration of applications.
Proof Theory of a Multi-Lane Spatial Logic
Authors: Linker Sven , Hilscher Martin
Published: November 2016

We extend the Multi-lane Spatial Logic MLSL, introduced in previous work for
proving the safety (collision freedom) of traffic maneuvers on a multi-lane
highway, by length measurement and dynamic modalities. We investigate the proof
theory of this extension, called EMLSL. To this end, we prove the
undecidability of EMLSL but nevertheless present a sound proof system which
allows for reasoning about the safety of traffic situations. We illustrate the
latter by giving a formal proof for the reservation lemma we could only prove
informally before. Furthermore we prove a basic theorem showing that the length
measurement is independent from the number of lanes on the highway.
Deciding definability in FO2(<h,<v) on trees
Authors: Place Thomas , Segoufin Luc
Published: November 2016

We provide a decidable characterization of regular forest languages definable
in FO2(<h,<v). By FO2(<h,<v) we refer to the two variable fragment of first
order logic built from the descendant relation and the following sibling
relation. In terms of expressive power it corresponds to a fragment of the
navigational core of XPath that contains modalities for going up to some
ancestor, down to some descendant, left to some preceding sibling, and right to
some following sibling. We also show that our techniques can be applied to
other two variable first-order logics having exactly the same vertical
modalities as FO2(<h,<v) but having different horizontal modalities.
Preservation and decomposition theorems for bounded degree structures
Authors: Harwath Frederik , Heimberg Lucas , Schweikardt Nicole
Published: November 2016

We provide elementary algorithms for two preservation theorems for
first-order sentences (FO) on the class \^ad of all finite structures of degree
at most d: For each FO-sentence that is preserved under extensions
(homomorphisms) on \^ad, a \^ad-equivalent existential (existential-positive)
FO-sentence can be constructed in 5-fold (4-fold) exponential time. This is
complemented by lower bounds showing that a 3-fold exponential blow-up of the
computed existential (existential-positive) sentence is unavoidable. Both
algorithms can be extended (while maintaining the upper and lower bounds on
their time complexity) to input first-order sentences with modulo m counting
quantifiers (FO+MODm). Furthermore, we show that for an input FO-formula, a
\^ad-equivalent Feferman-Vaught decomposition can be computed in 3-fold
exponential time. We also provide a matching lower bound.
Type-based Self-stabilisation for Computational Fields
Authors: Damiani Ferruccio , Viroli Mirko
Published: November 2016

Emerging network scenarios require the development of solid large-scale
situated systems. Unfortunately, the diffusion/aggregation computational
processes therein often introduce a source of complexity that hampers
predictability of the overall system behaviour. Computational fields have been
introduced to help engineering such systems: they are spatially distributed
data structures designed to adapt their shape to the topology of the underlying
(mobile) network and to the events occurring in it, with notable applications
to pervasive computing, sensor networks, and mobile robots. To assure
behavioural correctness, namely, correspondence of micro-level specification
(single device behaviour) with macro-level behaviour (resulting global spatial
pattern), we investigate the issue of self-stabilisation for computational
fields. We present a tiny, expressive, and type-sound calculus of computational
fields, and define sufficient conditions for self-stabilisation, defined as the
ability to react to changes in the environment finding a new stable state in
finite time. A type-based approach is used to provide a correct checking
procedure for self-stabilisation.
Formal Design of Asynchronous Fault Detection and Identification Components using Temporal Epistemic Logic
Authors: Bozzano Marco , Cimatti Alessandro , Gario Marco , Tonetta Stefano
Published: November 2016

Autonomous critical systems, such as satellites and space rovers, must be
able to detect the occurrence of faults in order to ensure correct operation.
This task is carried out by Fault Detection and Identification (FDI)
components, that are embedded in those systems and are in charge of detecting
faults in an automated and timely manner by reading data from sensors and
triggering predefined alarms. The design of effective FDI components is an
extremely hard problem, also due to the lack of a complete theoretical
foundation, and of precise specification and validation techniques. In this
paper, we present the first formal approach to the design of FDI components for
discrete event systems, both in a synchronous and asynchronous setting. We
propose a logical language for the specification of FDI requirements that
accounts for a wide class of practical cases, and includes novel aspects such
as maximality and trace-diagnosability. The language is equipped with a clear
semantics based on temporal epistemic logic, and is proved to enjoy suitable
properties. We discuss how to validate the requirements and how to verify that
a given FDI component satisfies them. We propose an algorithm for the synthesis
of correct-by-construction FDI components, and report on the applicability of
the design approach on an industrial case-study coming from aerospace.