280 research outputs found
Online semi-supervised learning in non-stationary environments
Existing Data Stream Mining (DSM) algorithms assume the availability of labelled and
balanced data, immediately or after some delay, to extract worthwhile knowledge from the
continuous and rapid data streams. However, in many real-world applications such as
Robotics, Weather Monitoring, Fraud Detection Systems, Cyber Security, and Computer
Network Traffic Flow, an enormous amount of high-speed data is generated by Internet of
Things sensors and real-time data on the Internet. Manual labelling of these data streams
is not practical due to time consumption and the need for domain expertise. Another
challenge is learning under Non-Stationary Environments (NSEs), which occurs due to
changes in the data distributions in a set of input variables and/or class labels. The problem
of Extreme Verification Latency (EVL) under NSEs is referred to as Initially Labelled Non-Stationary Environment (ILNSE). This is a challenging task because the learning algorithms
have no access to the true class labels directly when the concept evolves. Several approaches
exist that deal with NSE and EVL in isolation. However, few algorithms address both issues
simultaneously. This research directly responds to ILNSEâs challenge in proposing two
novel algorithms âPredictor for Streaming Data with Scarce Labelsâ (PSDSL) and
Heterogeneous Dynamic Weighted Majority (HDWM) classifier. PSDSL is an Online Semi-Supervised Learning (OSSL) method for real-time DSM and is closely related to label
scarcity issues in online machine learning.
The key capabilities of PSDSL include learning from a small amount of labelled data in an
incremental or online manner and being available to predict at any time. To achieve this,
PSDSL utilises both labelled and unlabelled data to train the prediction models, meaning it
continuously learns from incoming data and updates the model as new labelled or
unlabelled data becomes available over time. Furthermore, it can predict under NSE
conditions under the scarcity of class labels. PSDSL is built on top of the HDWM classifier,
which preserves the diversity of the classifiers. PSDSL and HDWM can intelligently switch
and adapt to the conditions. The PSDSL adapts to learning states between self-learning,
micro-clustering and CGC, whichever approach is beneficial, based on the characteristics of
the data stream. HDWM makes use of âseedâ learners of different types in an ensemble to
maintain its diversity. The ensembles are simply the combination of predictive models
grouped to improve the predictive performance of a single classifier.
PSDSL is empirically evaluated against COMPOSE, LEVELIW, SCARGC and MClassification
on benchmarks, NSE datasets as well as Massive Online Analysis (MOA) data streams and real-world datasets. The results showed that PSDSL performed significantly better than
existing approaches on most real-time data streams including randomised data instances.
PSDSL performed significantly better than âStaticâ i.e. the classifier is not updated after it is
trained with the first examples in the data streams. When applied to MOA-generated data
streams, PSDSL ranked highest (1.5) and thus performed significantly better than SCARGC,
while SCARGC performed the same as the Static. PSDSL achieved better average prediction
accuracies in a short time than SCARGC.
The HDWM algorithm is evaluated on artificial and real-world data streams against existing
well-known approaches such as the heterogeneous WMA and the homogeneous Dynamic
DWM algorithm. The results showed that HDWM performed significantly better than WMA
and DWM. Also, when recurring concept drifts were present, the predictive performance of
HDWM showed an improvement over DWM. In both drift and real-world streams,
significance tests and post hoc comparisons found significant differences between
algorithms, HDWM performed significantly better than DWM and WMA when applied to
MOA data streams and 4 real-world datasets Electric, Spam, Sensor and Forest cover. The
seeding mechanism and dynamic inclusion of new base learners in the HDWM algorithms
benefit from the use of both forgetting and retaining the models. The algorithm also
provides the independence of selecting the optimal base classifier in its ensemble depending
on the problem.
A new approach, Envelope-Clustering is introduced to resolve the cluster overlap conflicts
during the cluster labelling process. In this process, PSDSL transforms the centroidsâ
information of micro-clusters into micro-instances and generates new clusters called
Envelopes. The nearest envelope clusters assist the conflicted micro-clusters and
successfully guide the cluster labelling process after the concept drifts in the absence of true
class labels. PSDSL has been evaluated on real-world problem âkeystroke dynamicsâ, and
the results show that PSDSL achieved higher prediction accuracy (85.3%) and SCARGC
(81.6%), while the Static (49.0%) significantly degrades the performance due to changes in
the users typing pattern. Furthermore, the predictive accuracies of SCARGC are found
highly fluctuated between (41.1% to 81.6%) based on different values of parameter âkâ
(number of clusters), while PSDSL automatically determine the best values for this
parameter
LIPIcs, Volume 261, ICALP 2023, Complete Volume
LIPIcs, Volume 261, ICALP 2023, Complete Volum
Mathematical Methods and Operation Research in Logistics, Project Planning, and Scheduling
In the last decade, the Industrial Revolution 4.0 brought flexible supply chains and flexible design projects to the forefront. Nevertheless, the recent pandemic, the accompanying economic problems, and the resulting supply problems have further increased the role of logistics and supply chains. Therefore, planning and scheduling procedures that can respond flexibly to changed circumstances have become more valuable both in logistics and projects. There are already several competing criteria of project and logistic process planning and scheduling that need to be reconciled. At the same time, the COVID-19 pandemic has shown that even more emphasis needs to be placed on taking potential risks into account. Flexibility and resilience are emphasized in all decision-making processes, including the scheduling of logistic processes, activities, and projects
Eddy current defect response analysis using sum of Gaussian methods
This dissertation is a study of methods to automatedly detect and produce approximations of eddy current differential coil defect signatures in terms of a summed collection of Gaussian functions (SoG). Datasets consisting of varying material, defect size, inspection frequency, and coil diameter were investigated. Dimensionally reduced representations of the defect responses were obtained utilizing common existing reduction methods and novel enhancements to them utilizing SoG Representations. Efficacy of the SoG enhanced representations were studied utilizing common Machine Learning (ML) interpretable classifier designs with the SoG representations indicating significant improvement of common analysis metrics
LIPIcs, Volume 258, SoCG 2023, Complete Volume
LIPIcs, Volume 258, SoCG 2023, Complete Volum
City marketing and convention bureaus value propositions in the post-covid time
City marketing and convention bureaus value propositions in the post-covid timeThe role of convention bureaus across the world is to market destinations and cities.This paper explores destination marketing in the post pandemic time. It focusses on thevalues that convention bureaus, a key actor in the meetings industry, propose topotential visitors. The concept of value propositions (VPs) is commonly regarded as astrategic tool for organizations to communicate what and how they will provide benefitsto clients in their offerings of products or services (Payne, Frow and Eggert 2017, Payneet al. 2020). A value proposition is a central part of the business model. VPs can bethought of in terms of promises made to clients or to market segments in externalcommunication (Grönroos and Voima 2013). This calls for an appropriate packaging andpresentation of the values in the communication of organisations (Payne, et al. 2017).From a strategic perspective, VPs affects the process communicating and deliveringvalues (Lanning 2020). Previous research of VPs within in tourism studies include valueco-creation and co-destruction in tourism services (Assiouras et al. 2022), value andtourist brand loyalty (Bose et al. 2022), tourism stakeholder value-co creation (Carrasco-FarrĂ© et al. 2022), value propositions in digitalisation processes (Endres et al. 2020) valuepropositions for community building (Butler and Szromek 2019), power in tourismmarketing (Kannisto 2016) and values in experience design (Tussyadiah 2014). The topicappears however to be understudied from a communication perspective and also withrespect to how unexpected events, such as the pandemic, frame the processes ofcommunicating values. The aim of this paper is to advance the knowledge about valuepropositions socio-cultural dimensions by exploring how benefits for meetings bookersand visitors are discursively constructed. The study will answer three questions: how isvalue proposed in the marketing communication of convention bureaus, and whatprofessional meetings discourses are formed in the post covid time?Case, method and theoryTexts and images in the online marketing of 20 convention bureaus (CBs) was collectedbetween May 2022 and March 2023. Dispersed across five world continents, most CBsare located in large cities. A CBs main purpose is to increase the number of meetings ina destination. CBs collaborate with companies in its area to market their offerings, andthey are often a unit of a DMO of a city or a municipality's business department. Themeetings industry increased its activity in the beginning of 2022, when all restrictionswere gradually lifted, and therefore the data constitute an example of marketing thatwas planned and executed during a crisis. The material was imported and text-scannedin NVivo software. Codes were created inductively, by identifying presentations ofbenefits in chunks of texts and images that were manually coded as value propositions,screenshot by screenshot. Inspired by discourse theory (Wetherell et al. 2001), thesecond step of the analysis aimed for a more abstract level. The theory wasoperationalized by looking for reoccurring expressions used to propose value, terms,narratives, symbols, metaphors, and images, and by identifying things that are excluded,and ambiguities in the communication. A set of identified values emerged, as a map ofhow convention bureaus on a global level imagine the meetings demand. The analysis2discusses some vantage points that the CBs depart from. The analytical perspective thusprovides a broad societal interpretation of the themes.FindingsTwo main VP discourses emerged. First, the offering of âThe meeting in a destinationâ isconstructed as place-bound meetings. Place is represented in images of historicalbuildings, spectacular nature, or references to place specific professional networks. Thecommunicated benefits emphasise physical interactions and location in relation to otherplaces. The place bound discourse constructs an essential need of being and engaging ininteractions and experience place, for successful meetings. The CBs engage in aplaceification of professional meetings.Second, the âSustainable meetingsâ is a morally packaged offering, that is often basedon presenting benefits of ethical concern such as expressions of care for theenvironment or displays of certifications and expert lists of wise consumption choices.This offering thus constructs morally conscious and responsible choices at the center ofa good meeting. Sustainable consumption is constructed as a norm, in this ethicificationof the professional meetings offering. In sum, the representations relate to differentnorms like mobility and the ethical. The first emphasises experiences of place, whichpartly contradicts the offering of sustainability, The placeification contradicts theethicification of meetings, in so far that places require physical infrastructures andtravelling. The ethicification of meetings stress on the other hand travelling aspotentially harmful for the environment. The sustainability theme does not stress lesstravelling, it rather suggests alternative forms.Discussion and conclusionsThe communication can be interpreted as formations of new norms emerging in relationto change in society. The meeting industry has always emphasised the value of a specificlocation for meetings, an essential part of the tourism industry business models.Revenues depend on sold rooms, dinners, and personal service in that place.Experiences of place requires people to be there. This communication may thereforeseem like a given vantage point. However, digitalisation of society has acceleratedduring Covid-19 pandemic and it seems to have paved a way for customer segments thatdo not want to, or cannot not travel to a remote destination, for different reasons.Especially urgent during the pandemic and to some extent still valid, digital meetingformats are still used. The meeting industry have had to address the question ofmobility, where digital meetings formats could be part of a possible venue in asustainable direction. Carbon emissions from aviation is a significant contributor toclimate change while a lot of people around the world go to meetings by plane, on aregular basis. It may be that the industry addresses these challenges by promotingsustainable meetings. Hence the communication discursively establishes the meetingsindustry as a player within sustainable development. Communication can trivializeconceptions of sustainable challenges and this study suggests that value propositionsare powerful communicative tools and that value propositions emerge in relation tochange in society.References3Assiouras, Ioannis, et al. (2022), 'Value propositions during service mega-disruptions:Exploring value co-creation and value co-destruction in service recovery',ANNALS OF TOURISM RESEARCH, 97.Ballantyne, D., P. Frow, R. J. Varey and A. Payne (2011). "Value propositions ascommunication practice: Taking a wider view." Industrial MarketingManagement 40 (2): 202-210.Bose, Sunny, et al. (2022), 'Customer-Based Place Brand Equity and Tourism: A Regional IdentityPerspective', Journal of Travel Research, 61 (3), 511-27.Butler, R. W. and Szromek, A. R. (2019), 'Incorporating the value proposition for society withbusiness models of health tourism enterprises', Sustainability, 11 (23), 6711.Carrasco-FarrĂ©, Carlos, et al. (2022), 'The stakeholder value proposition of digital platforms in anurban ecosystem', Research Policy, 51 (4), N.PAG-N.PAG.Christensen, E. Christensen and L. T. (2022). The saying and the doing. Research handbook onstrategic communication. J. Falkheimer and M. Heide, Edward Elgar Publishing.Christensen, L. T., O. Thyssen and M. Morsing (2020). "TalkâAction Dynamics: Modalities ofaspirational talk." Organization Studies.du Gay, P. and Pryke, M. (2002), Cultural Economy: Cultural Analysis and Commercial Life (SAGEPublications).Endres, Herbert, Stoiber, Kristina, and Wenzl, Nina Magdalena (2020), 'Managing digitaltransformation through hybrid business models', Journal of Business Strategy, 41 (6),49-56.Gieben, B. and S. Hall (1992). Formations of modernity, Polity Press in association with the OpenUniv.Grönroos, Christian and Voima, PĂ€ivi (2013), 'Critical service logic: making sense of valuecreation and co-creation', Journal of the Academy of Marketing Science, 41 (2), 133-50.Hall, S. In Wetherell, M., S. Taylor and S. J. Yates (2001). Discourse Theory and Practice: A Reader,SAGE Publications.Kannisto, PĂ€ivi (2016), 'âI'M NOT A TARGET MARKETâ: Power asymmetries in marketsegmentation', Tourism Management Perspectives, 20, 174-80.Kodish, S. and L. Pettegrew (2008). "Enlightened Communication Is the Key to BuildingRelationships." Journal of Relationship Marketing 7(2): 151-176.Lanning, M. J. (2020). "Try taking your value proposition seriously - Why delivering winning valuepropositions should be but usually is not the core strategy for B2B (and otherbusinesses)." Industrial Marketing Management 87: 306-308.Payne, A., P. Frow and A. Eggert (2017). "The customer value proposition: evolution,development, and application in marketing." Journal of the Academy of MarketingScience: Official Publication of the Academy of Marketing Science 45(4): 467-489.Payne, A., P. Frow, L. Steinhoff and A. Eggert (2020). "Toward a comprehensive framework ofvalue proposition development: From strategy to implementation." IndustrialMarketing Management 87: 244-255.Truong, Y., G. Simmons and M. Palmer (2012). "Reciprocal value propositions in practice:Constraints in digital markets." Industrial Marketing Management 41(1): 197-206.Tussyadiah, Iis P. (2014), 'Toward a Theoretical Foundation for Experience Design in Tourism',Journal of Travel Research, 53 (5), 543-64.Wetherell, M., Taylor, S., and Yates, S.J. (2001), Discourse Theory and Practice: A Reader (SAGEPublications).Winther Jörgensen, M. and L. Phillips (1999). Diskursanalys som teori och metod. Lund,Studentlitteratur.
Advances of Machine Learning in Materials Science: Ideas and Techniques
In this big data era, the use of large dataset in conjunction with machine
learning (ML) has been increasingly popular in both industry and academia. In
recent times, the field of materials science is also undergoing a big data
revolution, with large database and repositories appearing everywhere.
Traditionally, materials science is a trial-and-error field, in both the
computational and experimental departments. With the advent of machine
learning-based techniques, there has been a paradigm shift: materials can now
be screened quickly using ML models and even generated based on materials with
similar properties; ML has also quietly infiltrated many sub-disciplinary under
materials science. However, ML remains relatively new to the field and is
expanding its wing quickly. There are a plethora of readily-available big data
architectures and abundance of ML models and software; The call to integrate
all these elements in a comprehensive research procedure is becoming an
important direction of material science research. In this review, we attempt to
provide an introduction and reference of ML to materials scientists, covering
as much as possible the commonly used methods and applications, and discussing
the future possibilities.Comment: 80 pages; 22 figures. To be published in Frontiers of Physics, 18,
xxxxx, (2023
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