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  • 2901.
    Zdravkovic, Jelena
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Zikra, Iyad
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Ilayperuma, Tharaka
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    An MDA Method for Service Modeling by Formalizing REA and Open-edi Business Frameworks with SBVR2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Business frameworks offer great opportunities of communication between people for working on the enterprise system engineering processes, as well as for eliciting services that the enterprise can offer in collaboration contexts. However, these kinds of frameworks, such as Resource-Event-Agent and Open-edi, recently unified in Open-edi Business Ontology (OeBTO), lack formal representations. This fact considerably limits their use in system development, particularly in model-driven development methods where the efficiency of transformations is of great importance. In this paper we suggest a formalization of OeBTO using OMG’s standard Semantics of Business Vocabulary and Business Rules (SBVR), as a method for creating a service-centric business model. This makes it possible to provide the necessary formal logic foundation to allow automatic processing of the business model and its transformation to a system-level service model. An example from the bank loan business sector is used to argument the application of the method.

  • 2902.
    Zeynep, Ahmet
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Holmquist, Lars Erik
    Sharing mobile services - Beyond the app store model2010Ingår i: MobileHCI 2010, ACM Press , 2010Konferensbidrag (Övrigt vetenskapligt)
  • 2903.
    Zeynep, Ahmet
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Jonsson, Martin
    Holmquist, Lars Erik
    Sumon, Saiful Islam
    Supporting embodied exploration of physical concepts in mixed digital and physical interactive settings2011Ingår i: TEI 2011, ACM Press , 2011Konferensbidrag (Övrigt vetenskapligt)
  • 2904.
    Zeynep, Ahmet
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Cramer, Henriette
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Holmquist, Lars Erik
    SICS / Mobile Life, , .
    Rost, Mattias
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Gamification and location-sharing: Some emerging social conflicts2011Ingår i: CHI2011, Vancouver, Canada: ACM Press , 2011Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Location-sharing services such as foursquare are a prominent example of commercial apps that use gamification to increase user engagement. These gamification elements however have to coexist with a plethora of usage motivations. We here present selected observations on emerging conflicts between gamification elements and other usage motivations for location-sharing. We argue gamification needs to take into account the social context in which services operate and that conflicts within this context can both be detrimental and add to playfulness.

  • 2905.
    Zeynep, Ahmet
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Väänänen-Vainio Mattila, Kaisa
    Tampere University of Technology, , .
    Face to face makes a difference: Recommendation Practices of Users of Mobile Services2011Ingår i: UbiComp2011, Beijing, China: ACM Press , 2011Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The mobile app stores and markets provide companies, independent developers and researchers alike with possibilities to distribute innovative designs for mobile devices on a global scale. However, reaching a large numbers of users does not in itself ensure a large number of users adopting the mobile application or service. Large-scale adoption depends on additional factors such as novelty in service design, ease of use, enjoyable interaction, built-in mechanisms for further distribution of the mobile service as well as the practice of word-of-mouth recommendations. In this position paper we present the background and preliminary findings from a study aimed at investigating the motivations and practices by which users recommend mobile apps and services among their acquaintances. We discuss our perspective on distribution of mobile applications and services on a large scale and end this paper by suggesting questions for discussion and future research.

  • 2906. Zhang, Ji-hong
    et al.
    Chen, Xi
    Ding, Xiao-song
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap. Beijing Foreign Studies University, China.
    Degeneracy removal in cutting plane methods for disjoint bilinear programming2017Ingår i: Optimization Letters, ISSN 1862-4472, E-ISSN 1862-4480, Vol. 11, nr 3, 483-495 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Disjoint bilinear programming has appeared in miscellaneous practical applications. Although deterministic approaches such as cutting plane methods for solving it have been proposed, the frequently encountered computational problem regarding degeneracy still remains. This paper proposes a distance-following approach in order to generate a conservative hyperplane from a degenerate local star minimizer located by the augmented mountain climbing procedure, cut off it, and thus enable a cutting plane method to proceed without too much additional computational workload.

  • 2907. Zhang, Pengyi
    et al.
    Liu, Chang
    Hansen, Preben
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    I Need More Time!: The Influence of Native Language on Search Behavior and Experience2016Ingår i: Working Notes of CLEF 2016 - Conference and Labs of the Evaluation forum: CEUR Proceedings / [ed] Krisztian Balog, Linda Cappellato, Nicola Ferro, Craig Macdonald, 2016, 1166-1182 s.Konferensbidrag (Refereegranskat)
  • 2908.
    Zhang, Yanqing
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Constructing Swedish Fashion Identity Exhibition Review: Svenskt Mode (Swedish Fashion): 2000–2015, Sven-Harry’s Art Museum, Stockholm, May 23–August 31, 20142015Ingår i: Fashion theory, ISSN 1362-704X, E-ISSN 1751-7419Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This is an exhibition review article. It describes the goal, the curatorship, display and exhibited objects. The exhibition focuses on Swedish fashion design and treats fashion as something in relation to art. It analyzes the exhibition as part of institutionalization of Swedish fashion system. Understanding fashion as a system rather than material clothing is the key point here.

  • 2909.
    Zhang, Yanqing
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Tech Fashion: Fashion Institutionalization in Digital Technology2016Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis explores aesthetization in general and fashion in particular in digital technology design and how we can design digital technology to account for the extended influences of fashion. The thesis applies a combination of methods to explore the new design space at the intersection of fashion and technology. First, it contributes to theoretical understandings of aesthetization and fashion institutionalization that influence digital technology design. We show that there is an unstable aesthetization in mobile design and the increased aesthetization is closely related to the fashion industry. Fashion emerged through shared institutional activities, which are usually in the form of action nets in the design of digital devices. “Tech Fashion” is proposed to interpret such dynamic action nets of institutional arrangements that make digital technology fashionable and desirable. Second, through associative design research, we have designed and developed two prototypes that account for institutionalized fashion values, such as the concept “outfit-centric accessory.” We call for a more extensive collaboration between fashion design and interaction design.

  • 2910.
    Zhang, Yanqing
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Juhlin, Oskar
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Fashion as System or Action Net in ‘Fashion in All Things’: a Case in Color Design of Mobile Phones2012Ingår i: Fashion: Exploring Critical Issues / [ed] Barbara Brownie, Laura Petican, Johannes Reponen, Oxford: Inter-Disciplinary Press, 2012, nr 1, 263-270 s.Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    Contemporary fashion has permeated into all things in life beyond clothes. Recently, fashion theories take on interests in organization and system. Kawamura proposes a fashion system through which clothing is transformed into the idea of fashion. Can this fashion system be used to analyze other things in fashion? We present a study using mobile phone, one of the most intimate gadgets to people, as a way to approach ‘fashion in all things’. We chose the color as a way to study the fashion aspect in mobile design. Through the empirical study, we find that the decision making of color in mobile industry is a collective process. It is greatly influenced by technology, materials, consumer lifestyle and trend. The trendy colors in mobile design are not defined by certain cultural or social institutions, but formulated by actions conducted by various actors in certain social context. Our study shows that fashion can embrace more than Kawamura’s system, e.g. the action net of color design in mobile technology. Although mobile design shares some similarities with clothing fashion, the concept of fashion-ology is very Parisian and deals with only clothing. It is not fully applicable to mobile industry. If we want to use a fashion system that can apply to fashion in all things, we should revisit the theory to reveal the general characteristics of the fashion world or build smaller theory for each category.

  • 2911.
    Zhang, Yanqing
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Juhlin, Oskar
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Fashion in Mobile Phone Design – The Emergence of Beautification, Desirability and Variation through Institutional Collaboration2016Ingår i: Fashion Practice: the journal of design, creative process & the fashion industry, ISSN 1756-9370, E-ISSN 1756-9389, Vol. 8, nr 1, 63-84 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We study if and how fashion values, such as beautification, desirability through symbolic interaction, and high variation, are increasingly visible in mobile phone design. We unpack such possible inter-linkages by interviewing eight representatives of both industries. Their comments allow us to discuss whether a process of fashionalization is underway and, if so, how it is taking place. Our findings indicate that fashion values are visible in the design of mobile phones and are accounted for in design. Fashionalization can thus be seen as emanating from institutions related to clothing that extend to and become shared with the mobile industry, such as a shared dependency on trend agencies for color selection and joint events. This interaction, ad hoc and heterogeneous, resists being modeled as a “system,” which has been suggested as a way to explain institutional work within clothing fashion. Drawing on Barbara Czarniawska’s institutional theory, we propose conceptualizing the emerging institutional work in terms of “action nets.” This concept makes visible flexible, situated, and ad hoc activities rather than stable and fixed organizational entities.

  • 2912.
    Zhang, Yanqing
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Juhlin, Oskar
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    The “life and death” of great Finnish fashion phone: A periodization of changing styles in Nokia phone design between 1992 and 20132016Ingår i: Mobile Media & Communication, ISSN 2050-1579, Vol. 4, nr 3, 385-404 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Visual aesthetics is an essential part of our experience of mobile devices, but the ways in which it is accounted for in design have largely been overlooked. We investigate whether an aesthetization of mobile design is taking place and, if so, how it is being pursued through institutional practices in organizations. We conduct a visual analysis of all Nokia phone releases between 1992 and 2013 complemented by an interview series with key actors. The study reveals a continuous increase in aesthetic variation between 1998 and 2008, which is visible in the variation of colors, forms and materials. The period between 2003 and 2008, which we term the Grand period, marks the peak of aesthetization of Nokia’s devices. It exhibits great variation, and is visibly similar to aesthetics in the fashion industry. With the introduction of the slate form, we see a decrease in visual variation between 2009 and 2013. The interviews reveal how the visual design was driven by organizational strategies, such as customer segmentation in general, and an orientation toward the fashion industry, e.g. in the creation of a fashion segment. The study reveals how aesthetic variation is weaved into a complex innovation system with sometimes conflicting demands deriving from e.g. technology and user interaction.

  • 2913.
    Zhao, Jing
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Learning Predictive Models from Electronic Health Records2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The ongoing digitization of healthcare, which has been much accelerated by the widespread adoption of electronic health records, generates unprecedented amounts of clinical data in a readily computable form. This, in turn, affords great opportunities for making meaningful secondary use of clinical data in the endeavor to improve healthcare, as well as to support epidemiology and medical research. To that end, there is a need for techniques capable of effectively and efficiently analyzing large amounts of clinical data. While machine learning provides the necessary tools, learning effective predictive models from electronic health records comes with many challenges due to the complexity of the data. Electronic health records contain heterogeneous and longitudinal data that jointly provides a rich perspective of patient trajectories in the healthcare process. The diverse characteristics of the data need to be properly accounted for when learning predictive models from clinical data. However, how best to represent healthcare data for predictive modeling has been insufficiently studied. This thesis addresses several of the technical challenges involved in learning effective predictive models from electronic health records.

    Methods are developed to address the challenges of (i) representing heterogeneous types of data, (ii) leveraging the concept hierarchy of clinical codes, and (iii) modeling the temporality of clinical events. The proposed methods are evaluated empirically in the context of detecting adverse drug events in electronic health records. Various representations of each type of data that account for its unique characteristics are investigated and it is shown that combining multiple representations yields improved predictive performance. It is also demonstrated how the information embedded in the concept hierarchy of clinical codes can be exploited, both for creating enriched feature spaces and for decomposing the predictive task. Moreover, incorporating temporal information leads to more effective predictive models by distinguishing between event occurrences in the patient history. Both single-point representations, using pre-assigned or learned temporal weights, and multivariate time series representations are shown to be more informative than representations in which temporality is ignored. Effective methods for representing heterogeneous and longitudinal data are key for enhancing and truly enabling meaningful secondary use of electronic health records through large-scale analysis of clinical data.

  • 2914.
    Zhao, Jing
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Temporal weighting of clinical events in electronic health records for pharmacovigilance2015Ingår i: 2015 IEEE International Conference on Bioinformatics and Biomedicine: Proceedings / [ed] Jun (Luke) Huan et al., IEEE Computer Society, 2015, 375-381 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Electronic health records (EHRs) have recently been identified as a potentially valuable source for monitoring adverse drug events (ADEs). However, ADEs are heavily under- reported in EHRs. Using machine learning algorithms to automatically detect patients that should have had ADEs reported in their health records is an efficient and effective solution. One of the challenges to that end is how to take into account temporality when using clinical events, which are time stamped in EHRs, as features for machine learning algorithms to exploit. Previous research on this topic suggests that representing EHR data as a bag of temporally weighted clinical events is promising; however, how to assign weights in an optimal manner remains unexplored. In this study, nine different temporal weighting strategies are proposed and evaluated using data extracted from a Swedish EHR database, where the predictive performance of models constructed with the random forest learning algorithm is compared. Moreover, variable importance is analyzed to obtain a deeper understanding as to why a certain weighting strategy is favored over another, as well as which clinical events undergo the biggest changes in importance with the various weighting strategies. The results show that the choice of weighting strategy has a significant impact on the predictive performance for ADE detection, and that the best choice of weighting strategy depends on the target ADE and, specifically, on its dose-dependency.

  • 2915.
    Zhao, Jing
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Henriksson, Aron
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Learning temporal weights of clinical events using variable importance2016Ingår i: BMC Medical Informatics and Decision Making, ISSN 1472-6947, E-ISSN 1472-6947, Vol. 16, nr Suppl. 2, 71Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Longitudinal data sources, such as electronic health records (EHRs), are very valuable for monitoring adverse drug events (ADEs). However, ADEs are heavily under-reported in EHRs. Using machine learning algorithms to automatically detect patients that should have had ADEs reported in their health records is an efficient and effective solution. One of the challenges to that end is how to take into account the temporality of clinical events, which are time stamped in EHRs, and providing these as features for machine learning algorithms to exploit. Previous research on this topic suggests that representing EHR data as a bag of temporally weighted clinical events is promising; however, the weights were in that case pre-assigned according to their time stamps, which is limited and potentially less accurate. This study therefore focuses on how to learn weights that effectively take into account the temporality and importance of clinical events for ADE detection. Methods: Variable importance obtained from the random forest learning algorithm is used for extracting temporal weights. Two strategies are proposed for applying the learned weights: weighted aggregation and weighted sampling. The first strategy aggregates the weighted clinical events from different time windows to form new features; the second strategy retains the original features but samples them by using their weights as probabilities when building each tree in the forest. The predictive performance of random forest models using the learned weights with the two strategies is compared to using pre-assigned weights. In addition, to assess the sensitivity of the weight-learning procedure, weights from different granularity levels are evaluated and compared. Results: In the weighted sampling strategy, using learned weights significantly improves the predictive performance, in comparison to using pre-assigned weights; however, there is no significant difference between them in the weighted aggregation strategy. Moreover, the granularity of the weight learning procedure has a significant impact on the former, but not on the latter. Conclusions: Learning temporal weights is significantly beneficial in terms of predictive performance with the weighted sampling strategy. Moreover, weighted aggregation generally diminishes the impact of temporal weighting of the clinical events, irrespective of whether the weights are pre-assigned or learned.

  • 2916.
    Zhao, Jing
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Henriksson, Aron
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Asker, Lars
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Boström, Henrik
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Detecting Adverse Drug Events with Multiple Representations of Clinical Measurements2014Ingår i: 2014 IEEE International Conference on Bioinformatics and Biomedicine (BIBM): Proceedings, IEEE Computer Society, 2014, 536-543 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Adverse drug events (ADEs) are grossly under-reported in electronic health records (EHRs). This could be mitigated by methods that are able to detect ADEs in EHRs, thereby allowing for missing ADE-specific diagnosis codes to be identified and added. A crucial aspect of constructing such systems is to find proper representations of the data in order to allow the predictive modeling to be as accurate as possible. One category of EHR data that can be used as indicators of ADEs are clinical measurements. However, using clinical measurements as features is not unproblematic due to the high rate of missing values and they can be repeated a variable number of times in each patient health record. In this study, five basic representations of clinical measurements are proposed and evaluated to handle these two problems. An empirical investigation using random forest on 27 datasets from a real EHR database with different ADE targets is presented, demonstrating that the predictive performance, in terms of accuracy and area under ROC curve, is higher when representing clinical measurements crudely as whether they were taken or how many times they were taken by a patient. Furthermore, a sixth alternative, combining all five basic representations, significantly outperforms using any of the basic representation except for one. A subsequent analysis of variable importance is also conducted with this fused feature set, showing that when clinical measurements have a high missing rate, the number of times they were taken by one patient is ranked as more informative than looking at their actual values. The observation from random forest is also confirmed empirically using other commonly employed classifiers. This study demonstrates that the way in which clinical measurements from EHRs are presented has a high impact for ADE detection, and that using multiple representations outperforms using a basic representation.

  • 2917.
    Zhao, Jing
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Henriksson, Aron
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Asker, Lars
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Boström, Henrik
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Predictive modeling of structured electronic health records for adverse drug event detection2015Ingår i: BMC Medical Informatics and Decision Making, ISSN 1472-6947, E-ISSN 1472-6947, Vol. 15, nr SIArtikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: The digitization of healthcare data, resulting from the increasingly widespread adoption of electronic health records, has greatly facilitated its analysis by computational methods and thereby enabled large-scale secondary use thereof. This can be exploited to support public health activities such as pharmacovigilance, wherein the safety of drugs is monitored to inform regulatory decisions about sustained use. To that end, electronic health records have emerged as a potentially valuable data source, providing access to longitudinal observations of patient treatment and drug use. A nascent line of research concerns predictive modeling of healthcare data for the automatic detection of adverse drug events, which presents its own set of challenges: it is not yet clear how to represent the heterogeneous data types in a manner conducive to learning high-performing machine learning models. Methods: Datasets from an electronic health record database are used for learning predictive models with the purpose of detecting adverse drug events. The use and representation of two data types, as well as their combination, are studied: clinical codes, describing prescribed drugs and assigned diagnoses, and measurements. Feature selection is conducted on the various types of data to reduce dimensionality and sparsity, while allowing for an in-depth feature analysis of the usefulness of each data type and representation. Results: Within each data type, combining multiple representations yields better predictive performance compared to using any single representation. The use of clinical codes for adverse drug event detection significantly outperforms the use of measurements; however, there is no significant difference over datasets between using only clinical codes and their combination with measurements. For certain adverse drug events, the combination does, however, outperform using only clinical codes. Feature selection leads to increased predictive performance for both data types, in isolation and combined. Conclusions: We have demonstrated how machine learning can be applied to electronic health records for the purpose of detecting adverse drug events and proposed solutions to some of the challenges this presents, including how to represent the various data types. Overall, clinical codes are more useful than measurements and, in specific cases, it is beneficial to combine the two.

  • 2918.
    Zhao, Jing
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Henriksson, Aron
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Boström, Henrik
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Cascading Adverse Drug Event Detection in Electronic Health Records2015Ingår i: 2015 IEEE International Conference on Data Science and Advanced Analytics (DSAA): Proceedings, IEEE Computer Society, 2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    The ability to detect adverse drug events (ADEs) in electronic health records (EHRs) is useful in many medical applications, such as alerting systems that indicate when an ADE-specific diagnosis code should be assigned. Automating the detection of ADEs can be attempted by applying machine learning to existing, labeled EHR data. How to do this in an effective manner is, however, an open question. The issues addressed in this study concern the granularity of the classification task: (1) If we wish to predict the occurrence of ADE, is it advantageous to conflate the various ADE class labels prior to learning, or should they be merged post prediction? (2) If we wish to predict a family of ADEs or even a specific ADE, can the predictive performance be enhanced by dividing the classification task into a cascading scheme: predicting first, on a coarse level, whether there is an ADE or not, and, in the former case, followed by a more specific prediction on which family the ADE belongs to, and then finally a prediction on the specific ADE within that particular family? In this study, we conduct a series of experiments using a real, clinical dataset comprising healthcare episodes that have been assigned one of eight ADE-related diagnosis codes and a set of randomly extracted episodes that have not been assigned any ADE code. It is shown that, when distinguishing between ADEs and non-ADEs, merging the various ADE labels prior to learning leads to significantly higher predictive performance in terms of accuracy and area under ROC curve. A cascade of random forests is moreover constructed to determine either the family of ADEs or the specific class label; here, the performance is indeed enhanced compared to directly employing a one-step prediction. This study concludes that, if predictive performance is of primary importance, the cascading scheme should be the recommended approach over employing a one-step prediction for detecting ADEs in EHRs.

  • 2919.
    Zhao, Jing
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Henriksson, Aron
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Boström, Henrik
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Detecting Adverse Drug Events Using Concept Hierarchies of Clinical Codes2014Ingår i: 2014 IEEE International Conference on Healthcare Informatics: Proceedings, IEEE Computer Society, 2014, 285-293 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Electronic health records (EHRs) provide a potentially valuable source of information for pharmacovigilance. However, adverse drug events (ADEs), which can be encoded in EHRs with specific diagnosis codes, are heavily under-reported. To provide more accurate estimates for drug safety surveillance, machine learning systems that are able to detect ADEs could be used to identify and suggest missing ADE-specific diagnosis codes. A fundamental consideration when building such systems is how to represent the EHR data to allow for accurate predictive modeling. In this study, two types of clinical code are used to represent drugs and diagnoses: the Anatomical Therapeutic Chemical Classification System (ATC) and the International Statistical Classification of Diseases and Health Problems (ICD). More specifically, it is investigated whether their hierarchical structure can be exploited to improve predictive performance. The use of random forests with feature sets that include only the original, low-level, codes is compared to using random forests with feature sets that contain all levels in the hierarchies. An empirical investigation using thirty datasets with different ADE targets is presented, demonstrating that the predictive performance, in terms of accuracy and area under ROC curve, can be significantly improved by exploiting codes on all levels in the hierarchies, compared to using only the low-level encoding. A further analysis is presented in which two strategies are employed for adding features level-wise according to the concept hierarchies: top-down, starting with the highest abstraction levels, and bottom-up, starting with the most specific encoding. The main finding from this subsequent analysis is that predictive performance can be kept at a high level even without employing the more specific levels in the concept hierarchies.

  • 2920.
    Zhao, Jing
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Henriksson, Aron
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Kvist, Maria
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap. Karolinska Institute, Sweden.
    Asker, Lars
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Boström, Henrik
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Handling Temporality of Clinical Events for Drug Safety Surveillance2015Ingår i: AMIA Annual Symposium Proceedings, ISSN 1559-4076, Vol. 2015, 1371-1380 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Using longitudinal data in electronic health records (EHRs) for post-marketing adverse drug event (ADE) detection allows for monitoring patients throughout their medical history. Machine learning methods have been shown to be efficient and effective in screening health records and detecting ADEs. How best to exploit historical data, as encoded by clinical events in EHRs is, however, not very well understood. In this study, three strategies for handling temporality of clinical events are proposed and evaluated using an EHR database from Stockholm, Sweden. The random forest learning algorithm is applied to predict fourteen ADEs using clinical events collected from different lengths of patient history. The results show that, in general, including longer patient history leads to improved predictive performance, and that assigning weights to events according to time distance from the ADE yields the biggest improvement.

  • 2921.
    Zhao, Jing
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Karlsson, Isak
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Asker, Lars
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Boström, Henrik
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Applying Methods for Signal Detection in Spontaneous Reports to Electronic Patient Records2013Ingår i: Proceedings of the  19th ACM SIGKDD International Conference on Knowledge Discovery and Data Mining, Association for Computing Machinery (ACM), 2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    Currently, pharmacovigilance relies mainly on disproportionality analysis of spontaneous reports. However, the analysis of spontaneous reports is concerned with several problems, such as reliability, under-reporting and insucient patient information. Longitudinal healthcare data, such as Electronic Patient Records (EPRs) in which comprehensive information of each patient is covered, is a complementary source of information to detect Adverse Drug Events (ADEs). A wide set of disproportionality methods has been developed for analyzing spontaneous reports to assess the risk of reported events being ADEs. This study aims to investigate the use of such methods for detecting ADEs when analyzing EPRs. The data used in this study was extracted from Stockholm EPR Corpus. Four disproportionality methods (proportional reporting rate, reporting odds ratio, Bayesian condence propagation neural network, and Gamma-Poisson shrinker) were applied in two dierent ways to analyze EPRs: creating pseudo spontaneous reports based on all observed drug-event pairs (event-level analysis) or analyzing distinct patients who experienced a drug-event pair (patient-level analysis). The methods were evaluated in a case study on safety surveillance of Celecoxib. The results showed that, among the top 200 signals, more ADEs were detected by the event-level analysis than by the patient-level analysis. Moreover, the event-level analysis also resulted in a higher mean average precision. The main conclusion of this study is that the way in which the disproportionality analysis is applied, the event-level or patient-level analysis, can have a much higher impact on the performance than which disproportionality method is employed.

  • 2922.
    Zhao, Jing
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Papapetrou, Panagiotis
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Asker, Lars
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Boström, Henrik
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Learning from heterogeneous temporal data from electronic health records2017Ingår i: Journal of Biomedical Informatics, ISSN 1532-0464, E-ISSN 1532-0480, Vol. 65, 105-119 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Electronic health records contain large amounts of longitudinal data that are valuable for biomedical informatics research. The application of machine learning is a promising alternative to manual analysis of such data. However, the complex structure of the data, which includes clinical events that are unevenly distributed over time, poses a challenge for standard learning algorithms. Some approaches to modeling temporal data rely on extracting single values from time series; however, this leads to the loss of potentially valuable sequential information. How to better account for the temporality of clinical data, hence, remains an important research question. In this study, novel representations of temporal data in electronic health records are explored. These representations retain the sequential information, and are directly compatible with standard machine learning algorithms. The explored methods are based on symbolic sequence representations of time series data, which are utilized in a number of different ways. An empirical investigation, using 19 datasets comprising clinical measurements observed over time from a real database of electronic health records, shows that using a distance measure to random subsequences leads to substantial improvements in predictive performance compared to using the original sequences or clustering the sequences. Evidence is moreover provided on the quality of the symbolic sequence representation by comparing it to sequences that are generated using domain knowledge by clinical experts. The proposed method creates representations that better account for the temporality of clinical events, which is often key to prediction tasks in the biomedical domain.

  • 2923.
    Zikra, Iyad
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Implementing the Unifying Meta-Model for Enterprise Modeling and Model-Driven Development: An Experience Report2012Ingår i: The Practice of Enterprise Modeling: 5th IFIP WG 8.1 Working Conference, PoEM 2012. Proceedings / [ed] Kurt Sandkuhl, Ulf Seigerroth, Janis Stirna, Springer, 2012, 172-187 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Model-Driven Development (MDD) is becoming increasingly popular as a choice for developing information systems. Tools that support the principles of MDD are also growing in number and variety of available functionality. MetaEdit+ is a meta-modeling tool used for developing Domain Specific Languages and is identified as an MDD tool. The Eclipse Modeling Framework (EMF) and Graphical Modeling Project (GMP) are two Eclipse projects that provide plug-ins to support the principles of MDD. In this paper, we report on our experience in using MetaEdit+ and the Eclipse plug-ins for developing a graphical editor for the unifying meta-model, which is an MDD approach that extends the traditional view of MDD to cover Enterprise Modeling. The two modeling environments are reviewed using functionality areas that are identified by the research community as necessary in MDD tools. This report will provide useful insights for researchers and practitioners alike concerning the use of MetaEdit+ and the Eclipse plug-ins as MDD tools.

  • 2924.
    Zikra, Iyad
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Integration of Enterprise Modeling and Model Driven Development: A Meta-Model and a Tool Prototype2014Licentiatavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    The use of models for designing and developing Information Systems (IS) has changed in recent years. Models are no longer considered a peripheral documentation medium that is poorly maintained and often neglected. Rather, models are increasingly seen as essential parts of the final product—as central artifacts that drive and guide the development efforts. The knowledge that modelers rely on when designing models is represented as formal models and clearly defined rules for transforming the models. The flexibility, reliability, and effectiveness offered by the formal models and the transformations are making Model Driven Development (MDD) a popular choice for building IS. Models also serve in describing enterprise design, where enterprise-level models capture organizational knowledge and aid in understanding, improving, and growing the enterprise. Enterprise Modeling (EM) offers a structured and unified view of the enterprise, thereby enabling more informed and accurate decisions to be made.

    Many MDD approaches have been proposed to tackle a wide range of IS-related issues, but little attention is being paid to the source of the knowledge captured by the IS models. EM approaches capture organizational knowledge and provide the necessary input and underlying context for designing IS. However, the results produced by EM approaches need to be manually analyzed by modelers to create the initial MDD model. This interruption of the MDD process represents a gap between enterprise models and MDD models. Limited research has been done to connect EM to MDD in a systematic and structured manner based on the principles of model-driven development.

    This thesis proposes a unifying meta-model for integrating EM and MDD. The meta-model captures the inherent links that exist between organizational knowledge and IS design. This helps to improve the alignment between organizational goals and the IS that are created to support them. The research presented herein follows the guidelines of the design science research methodology. It starts with a state-of-the-art survey of the current relationship between MDD and prior stages of development. The findings of the survey are used to elicit a set of necessary properties for integrating EM and MDD. The unifying meta-model is then proposed as the basis for an integrated IS development approach that applies the principles of MDD and starts on the enterprise level by considering enterprise models in the development process. The design of the meta-model supports the elicited integration properties. The unifying meta-model is based on the Enterprise Knowledge Development (EKD) approach to EM. A prototype tool is developed to support the unifying meta-model, following a study to choose a suitable implementation environment. The use of the unifying meta-model is demonstrated through the implemented tool platform using an example case study, revealing its advantages and highlighting the potential for improvement and future development.

  • 2925.
    Zikra, Iyad
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Model-based Requirements for Integrating Cloud Services2016Ingår i: Proceedings of the CAiSE'16 Forum, at the 28th International Conference on Advanced Information Systems Engineering (CAiSE 2016) / [ed] Sergio España, Mirjana Ivanović, Miloš Savić, 2016, 65-72 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Cloud-based services provide an alternative to the in-house implementation of various types of functionality. Organizations rely on such services to minimize the need for long-term commitments and enhance scalability and ubiquitous access to the services. However, achieving complex tasks that require a combination of services is not well studied, despite the potential added value. This paper investigates the requirements encountered when integrating cloud-based services in the modern organization. The paper proposes a model-driven solution for capturing the requirements for integrating cloud-based services. The model is to be used within the larger context of the organizational design; modeling components used to describe requirements are related to other views of the organization. A prototype tool and an example business case are presented to illustrate how the requirements model can be elicited and designed. The models are capable of being transformed into an integration solution.

  • 2926.
    Zikra, Iyad
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    The Communicative Nature of Information Systems Integration as an Enabler for Business IT Alignment2017Ingår i: Business Information Systems Workshops: BIS 2016 International Workshops, Leipzig, Germany, July 6-8, 2016, Revised Papers / [ed] Witold Abramowicz, Rainer Alt, Bogdan Franczyk, Springer, 2017, 136-147 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Patterns of systems integration strive to accommodate the diversity of business ecosystems, including novel Web- and cloud-based services. In this paper, we apply the principles of the language/action paradigm (LAP) to develop a decentralized integration pattern that supports dynamic integration of services. A model is proposed for designing the interacting systems as active and independent entities that seek to communicate with each other. Two modes are enabled in the communication model: an indirect mode, where systems interact via business processes; and a direct mode, where systems directly interface with each other, following four categories. The communication perspective of the proposed integration pattern contributes to realizing the vision of a marketplace for cloud services. It supports a more flexible alternative to centralized integra-tion patterns. The communication model builds on the improved alignment be-tween system design models and the overall organizational design offered by the unifying meta-model for enterprise modeling.

  • 2927.
    Zikra, Iyad
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    España, Sergio
    Ruiz, Marcela
    Pastor, Oscar
    Stirna, Janis
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Aligning Communication Analysis with the Unifying Meta-Model for Enterprise Modeling2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    Enterprise Modeling (EM) captures and represents organizational know-ledge in models that cover different views of the enterprise. The models can be leveraged in the development of information systems. Investigating how to use them as input to Model-Driven Development (MDD) is an open challenge. This paper explores how a holistic EM approach, represented by a unifying meta-model, can benefit from integrating with Communication Analysis, a communication-oriented business process modeling and requirements engineering method. As a first step towards an integrated EM-enabled MDD approach, the unifying meta-model and Communication Analysis meta-model are aligned. A set of guidelines for trans-forming models conforming to the unifying meta-model to Communication Analysis models are formulated. The approach is illustrated using of a lab demo.

  • 2928.
    Zikra, Iyad
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Stirna, Janis
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Zdravkovic, Jelena
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Analyzing the Integration between Requirements and Models in Model Driven Development2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    In Model Driven Development (MDD), models replace software code as the development artifact. At the same time, requirements represent the information that is elaborated in models. However, despite the tight relationship between models and requirements, only a few MDD approaches provide the necessary methodological guidelines and tool support to explicitly facilitate this relationship. In this paper, we analyze existing approaches for integrating requirements with models within MDD. Based on the analysis, we elicit a set of general properties that need to be fulfilled when considering the integration of requirements and models, and we assess the contribution of the considered approaches accordingly.

  • 2929.
    Zikra, Iyad
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Stirna, Janis
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Zdravkovic, Jelena
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Bringing Enterprise Modeling Closer to Model-Driven Development2011Ingår i: The Practice of Enterprise Modeling, Springer Berlin Heidelberg , 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Enterprise Modeling (EM) provides the means for using models to represent organizational knowledge from different perspectives. When information systems (IS) are involved, Model-Driven Development (MDD) is an approach that focuses on the use of models as primary development artifacts. By observing that EM provides the context for high level requirements, which in turn are the input to MDD, we propose a meta-model that integrates enterprise models and requirements with design models in MDD. The meta-model defines six models that cover both organizational and IS development knowledge. Inter-model relationships ensure an integrated view of the enterprise and the supporting IS by allowing model components to be used across different models. The integrated meta-model is demonstrated through an example case study.

  • 2930.
    Zikra, Iyad
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Stirna, Janis
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Zdravkovic, Jelena
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Identifying Quality Factors of Information Systems Integration Design2017Ingår i: Perspectives in Business Informatics Research: 16th International Conference, BIR 2017, Copenhagen, Denmark, August 28–30, 2017, Proceedings / [ed] Björn Johansson, Charles Møller, Atanu Chaudhuri, Frantisek Sudzina, Springer, 2017, 45-60 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Information Systems (IS) community has long recognized the importance of studying quality at various stages of the IS design process. Many studies target the quality factors at various stages of design and development. However, research about the factors that specifically affect the quality of IS integration remains largely fragmented. Existing quality frameworks fail to cover integration-specific factors. This motivates the need for a holistic model of integration quality. The paper proposes two artefacts to address this need. It explores the literature of related domains, including systems, model, and process quality to elicit the quality factors that are relevant in the context of IS integration. The factors can be used to evaluate the quality of integration solutions during design and development. The paper also proposes a quality model to describe the quality of the design components of integration solutions following the principles of model-driven development. The model enables the quality factors to be associated with other parts of the IS integration design. The proposed factors are evaluated with the help of expert feedback using a questionnaire, and the quality model is demonstrated with an example business case.

  • 2931.
    Ziyarazavi, Merat
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Magnusson, Christer
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    From Theory to Practice - When and How to Implement Service Value Agreement2013Ingår i: Journal of Service Science and Management, ISSN 1940-9893, E-ISSN 1940-9907, Vol. 6, 127-142 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Traditionally, a Service Level Agreement (SLA) is used as an appendix in IT Service Management agreements to set expectations and delineate the service delivery description as well as the terms and conditions of delivery. However, SLAs are unable to imply and guarantee the added values expected by the customer. Service Value Agreement (SVA) is a newly developed framework that identifies the deliverable added values along with metrics to measure the quality and quantity of achievements in terms of business added values. The objective of this study is to expand the concept of SVA for Application Management (AM) services and suggest guidelines for its implementation in real business cases. This goal is fulfilled through the case study approach and outsourcing industry contributions. Authors suggest discussing the concept of SVA from early stages of the sales lifecycle and implementing it gradually during the steady state phase. Combination of Service Value Mapping approach and Piloting method is suggested for SVA proposition as an option with successful practical history.

  • 2932. Ziyarazavi, Merat
    et al.
    Magnusson, Christer
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Tergesten, Torbjörn
    Qualifying and Quantifying IT Services Added Values in Outsourcing Assignments—Service Value Agreement2012Ingår i: Journal of Service Science and Management, ISSN 1940-9893, E-ISSN 1940-9907, Vol. 5, nr 4, 318-330 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Traditionally, a Service Level Agreement (SLA) including service level metrics is used as an appendix in IT Service Management agreements to define the terms and conditions of delivery and set expectations. However, SLA neither implies nor guarantees the added values that are expected by the customer. Besides, due to the nature of IT services, there always exists uncertainty about the agreed services due to which the perceived risk for both customer and provider is high. Moreover, the quality and quantity of delivered values are mostly hidden by hazy marketing slogans. In order to guarantee the values of an offered service, the deliverable added values should be characterized properly, quantified by means of measurable metrics, and agreed upon between the two parties. Such comprehensive material, including the deliverable added values along with their measurable metrics, is called Service Value Agreement (SVA). This research proposes a platform for IT service offerings based on added values by identifying, as well as quantifying, an organization’s objectives in purchasing Application Management (AM) services from a provider firm.

  • 2933. Zoric, Goranka
    et al.
    Barkhuus, Louise
    Engström, Arvid
    Önnevall, Elin
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Panoramic Video: Design Challenges and Implications for Content Interaction2013Ingår i: EuroITV '13: Proceedings of the 11th european conference on Interactive TV and video, New York: Association for Computing Machinery (ACM), 2013, 153-162 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we explore viewing and interaction in an emerging type of interactive TV, where viewers are presented with panoramic ultrahigh-definition video combined with extensive interactive control over view selection. Instead of delivering only what will be consumed, emerging TV services offer high- resolution panoramic video to the viewers, enabling them to more freely explore the broadcast content by selecting regions of interest and navigating within the larger panoramic image. However, as we open up the television space both in field of view and in terms of the freedom given to viewers, new interactional challenges emerge. We have done user studies on two systems for interacting with panoramic high-resolution video, one based on the tablet interaction and other on the gesture interaction. Our findings revealed a number of design challenges concerning properties specific to panoramic video. Based on findings from the user studies and the identified design challenges, we have compiled a set of the design recommendations on how to support interactive viewing of panoramic content.

  • 2934.
    Zoric, Goranka
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Engström, Arvid
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Barkhuus, Louise
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Hidalgo, Javier Ruiz
    Kochale, Axel
    Gesture Interaction with Rich TV Content in the Social Setting2014Ingår i: Proceedings of TVUX-2013: Workshop on Exploring and Enhancing the User Experience for TV at ACM CHI 2013, 27 April 2013, Paris, France, Association for Computing Machinery (ACM), 2014Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The appearance of new immersive TV content has increased the interactive possibilities presented to the viewers. Increased interactivity is seen as a valuable feature in viewing richer television content, but new functionalities are limited by what can be done naturally and intuitively using available devices like remote controls. Therefore, new interaction techniques, such as visual gestures control systems, have appeared aiming to enhance the viewers’ viewing experience. In this work we begin uncovering the potential and challenges of gesture interaction with ultra high definition video for people watching TV together. As a first step we have done a study with a group of people interacting with such content using a gesture-based system in the home environment.

  • 2935.
    Zuccato, Albin
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Kögler, Klemens
    Report: Functional Security Testing closing the software -- security testing gap - A case from a Telecom provider2009Ingår i: ESSOS 09, 2009Konferensbidrag (Refereegranskat)
  • 2936.
    Åhlfeldt, Rose-Mharie
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Information Security in Distributed Healthcare: Exploring the Needs for Achieving Patient Safety and Patient Privacy2008Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    In healthcare, patient information is a critical factor. The right information at the right time is a necessity in order to provide the best possible care for a patient. Patient information must also be protected from unauthorized access in order to protect patient privacy. It is furthermore common for patients to visit more than one healthcare provider, which implies a need for cross border healthcare and continuity in the patient process.

    This thesis is focused on information security in healthcare when patient information has to be managed and communicated between various healthcare actors and organizations. The work takes a practical approach with a set of investigations from different perspectives and with different professionals involved. Problems and needs have been identified, and a set of guidelines and recommendations has been suggested and developed in order to improve patient safety as well as patient privacy.

    The results show that a comprehensive view of the entire area concerning patient information management between different healthcare actors is missing. Healthcare, as well as patient processes, have to be analyzed in order to gather knowledge needed for secure patient information management.

    Furthermore, the results clearly show that there are deficiencies both at the technical and the administrative level of security in all investigated healthcare organizations.

    The main contribution areas are: an increased understanding of information security by elaborating on the administrative part of information security, the identification of information security problems and needs in cross border healthcare, and a set of guidelines and recommendations in order to advance information security measures in healthcare.

  • 2937.
    Åkerblom, Beatrice
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Wrigstad, Tobias
    Measuring Polymorphism in Python Programs2016Ingår i: SIGPLAN notices, ISSN 0362-1340, E-ISSN 1558-1160, Vol. 51, nr 2, 114-128 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Following the increased popularity of dynamic languages and their increased use in critical software, there have been many proposals to retrofit static type system to these languages to improve possibilities to catch bugs and improve performance. A key question for any type system is whether the types should be structural, for more expressiveness, or nominal, to carry more meaning for the programmer. For retrofitted type systems, it seems the current trend is using structural types. This paper attempts to answer the question to what extent this extra expressiveness is needed, and how the possible polymorphism in dynamic code is used in practise. We study polymorphism in 36 real-world open source Python programs and approximate to what extent nominal and structural types could be used to type these programs. The study is based on collecting traces from multiple runs of the programs and analysing the polymorphic degrees of targets at more than 7 million call-sites. Our results show that while polymorphism is used in all programs, the programs are to a great extent monomorphic. The polymorphism found is evenly distributed across libraries and program-specific code and occur both during program start-up and normal execution. Most programs contain a few megamorphic call-sites where receiver types vary widely. The non-monomorphic parts of the programs can to some extent be typed with nominal or structural types, but none of the approaches can type entire programs.

  • 2938.
    Åkerblom, Beatrice
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Wrigstad, Tobias
    Mattias, Tumlin
    Jonathan, Stendahl
    Tracing dynamic features in python program2014Ingår i: Proceedings of the 11th Working Conference on Mining Software Repositories, New York: ACM Press, 2014, 292-295 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Recent years have seen a number of proposals for adding (retrofitting) static typing to dynamic programming languages, a natural consequence of their growing popularity for non-toy applications across a multitude of domains. These proposals often make assumptions about how programmers write code, and in many cases restrict the way the languages can be used. In the context of Python, this paper describes early results from trace-based collection of run-time data about the use of built-in language features which are inherently hard to type, such as dynamic code generation. The end goal of this work is to facilitate static validation tooling for Python, in particular retrofitting of type systems.

  • 2939.
    Åkerfeldt, Anna
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för pedagogik och didaktik.
    Selander, Staffan
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Exploring educational video game design: meaning potentials and implications for learning2011Ingår i: Handbook of Research on Improving Learning and Motivation through Educational Games: Multidisciplinary Approaches / [ed] Patrick Felicia, 9781609604950: Information Science Reference , 2011, 1004-1018 s.Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    The aim of this chapter is to explore two educational video games as a repository for action and meaning-making. Rixdax and El Patron feature two different game genres and designs. Through a comparative analysis, it will be shown how these two games actually address very different learning goals and also seem to miss a crucial aspect of learning: reflective action. This chapter will investigate how the layout on the screen is composed and how knowledge is represented. To do so, six structuring factors introduced by Prensky (2001), some of the organizing principles of learning design developed by Selander (Selander, 2008a-b; 2009, Selander & Åkerfeldt, 2008) and the multimodal framework developed by Kress and van Leeuween (Kress & van Leeuween, 2006; Kress, 2010; van Leeuween, 2005) are used. The chapter analyses the individual elements as semiotic resources in the educational video game and show how these elements are represented, especially from the points of view of information value, salience and framing, but also how the information is sequenced, the tempo of the games and how they accommodate meta-reflection by the users.

  • 2940.
    Åkerlund, Kent
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Wettergren, Gunnar
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Student motivation in distance learning environments – what can we do as teachers to support it?2013Ingår i: 25th ICDE World Conference (16-18 September 2013, Tianjin, China): [Proceedings], 2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    Much has been said and written about learner satisfaction and how to motivate students in distance learning environments. Sun et al., (2008) proposes the instructor attitude toward e-learning as one significant factor for driving successful e-learning. Gilly Salmon (2003)states that it is of most importance to build communities in the educational platform and to design courses for interaction, participation and feedback. The need for Teacher–student interaction from a pedagogical point of view is undisputed, however focus in this discussion has often been on courses in a context where the three freedoms of distance learning (Freedom of time, place and pace) is some what limited to only include freedom of time and place. Free pace is often limited to fit the teachers and the administration of the course. This paper discusses the consequences of adding the third factor, freedom of pace for the student into the equation and applying it on a large course with 1000+ students. How do we treat the need of teacher – student interaction and the ability to build a community in a course of that size with limited resources available? The conclusions drawn in this paper come from teaching courses in project management both on an undergraduate and graduate level. The courses are given at the Department of Computer and Systems Sciences (DSV), Stockholm University and they are reached through the use of teacher discussions, self-introspective and practical experiences working as a teacher. In a course where students are allowed to study at their own pace (the third variable in the equation) it is almost impossible to create a personal relationship with individual students in the course. This in essence means that we as teachers and course creators must focus our attention on other task such as creating structure for students, making the course clear and easy to use, which is one of the biggest influences on motivation (Wettergren, 2011). The importance of quickness in reacting to student needs and questions is of utmost importance and enough resources should be devoted to this. In giving the courses at DSV we noticed a significant increase in student performance when imposing an 8-hour maximum response time from teachers. Students are studying when it fits their schedules making the timing of help and support when they are stuck even more important. The possibility to ask questions in public forums with quick responses from skilled tutors who facilitate the students to advance in the course created a sense of community. The presence of the teachers affects not only the students who asks the questions, but also the “lurkers” who get the information they need from reading other students questions. The implementation of scaffolding or “fictive” goals is an effective way of improving student motivation, giving them something to strive for (Wettergren, 2011). After implementing grading windows once a month, meaning that teachers only graded assignments and examination once a month we saw an increase in course throughput and student motivation. An added bonus of this implementation was that in doing so we created a more motivating and interesting teacher situation since we could focus on teaching and helping the students more since grading was concentrated to certain parts of the month.

  • 2941. Çelaj, Ilir
    et al.
    Rusu, Lazar
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    IT outsourcing relationships in Swedish public organizations2014Ingår i: Perspectives in Business Informatics Research: Proceedings, Springer, 2014, 15-29 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Information technology (IT) is not only beneficial for the private sector but has a lot to offer for the public sector as well. However, most of the studies in IT outsourcing relationships consider only the private sector and do not pay attention to the public sector. In this context, the research has looked to determine the influential factors in IT outsourcing relationships in Swedish public organizations like are Swedish municipalities and classified them according to the importance. The research methodology used has included a survey among IT outsourcing decision makers from Swedish municipalities and a case study in a Swedish municipality. The survey has revealed that trust, cooperation, commitment, communication, and flexibility are the top five most important factors which are influencing the provider-recipient IT outsourcing relationship in Swedish municipalities. While the case study has revealed that all the factors that were identified during the literature review are influencing the provider-recipient IT outsourcing relationship in Swedish municipalities plus the identification of two new factors which are legislation and economy/money.

  • 2942.
    Önnevall, Elin
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Television Practices: Ethnography, Television and User Practices2014Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis explores television practices in a time when new technology has made it possible to interact with and create your own TV content. The work is focused on how user practices need to be understood in a context of chan- ging technology. The practices studied also show the relevance of ethno- graphic methods, and especially the wide spectrum of these different meth- ods within the field of Human-Computer Interaction. We distinguish be- tween sociologically informed ethnography and anthropological ethnogra- phy. Two questions are addressed: how can new forms of television practices be understood by means of different ethnographic methods, and, on a wider level, what method can we use for analysing methods in ethnographic re- search? Because ethnographic methods are qualitative, we have also chosen to use an open and qualitative approach when analysing them. Through comparing our different methods – their data and findings on one specific topic – we have discovered the differences between the methodological ap- proaches.

  • 2943. Östlund, Johan
    et al.
    Wrigstad, Tobias
    Clarke, Dave
    Åkerblom, Beatrice
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Ownership, Uniqueness, Immutability2008Ingår i: 46th International Conference on Objects, Models, Components, Patterns (TOOLS-Europe), 2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    Programming in an object-oriented language demands a fine balance between flexibility and control. At one level, objects need to interact freely to achieve our implementation goals. At a higher level, architectural constraints that ensure the system can be understood by new developers and can evolve as requirements change must be met. To resolve this tension, researchers have developed type systems expressing ownership and behavioural restrictions such as immutability. This work reports on our consolidation of the resulting discoveries into a single programming language. Our language, Joe_3, imposes little additional syntactic overhead, yet can encode powerful patterns such as fractional permissions and the reference modes of Flexible Alias Protection.

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