A New Multidimensional Design Method Based on Meta Model Assistance

2017 ◽  
Vol 7 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Nazih Selmoune ◽  
Zaia Alimazighi

Data warehouses have become over the last two decades an essential element in the area of economic intelligence. Although the basic concepts related to this technology are now more standardized (multidimensional model, OLAP technology...), the design method issue remains in discussion, since no proposed method does seem attractive enough to be used rigorously in the real case studies. Indeed, most of the 'Data Warehouse projects' simply follow some design guidelines from the most informal methods. In this paper the authors propose an approach based on the use of the sources metadata to provide help in the multidimensional design. Their approach falls into the category of supply-driven methods, and attempts to cover the various stages of the lifecycle of data warehouses design. The proposed method is associated with a MultiDimensional Design Assistance environment (M2DA) to support the automatic and semi-automatic steps, providing the expected forms of assistance, and managing the interaction with the designer.

Author(s):  
Banek Marko ◽  
Vrdoljak Boris ◽  
Min Tjoa A ◽  
Skocir Zoran

A federated data warehouse is a logical integration of data warehouses applicable when physical integration is impossible due to privacy policy or legal restrictions. In healthcare systems federated data warehouses are a most feasible source of data for deducing guidelines for evidence-based medicine based on data material from different participating institutions. In order to enable the translation of queries in a federated approach, schemas of the federated warehouse and the local warehouses must be matched. In this paper we present a procedure that enables the matching process for schema structures specific to the multidimensional model of data warehouses: facts, measures, dimensions, aggregation levels and dimensional attributes. Similarities between warehouse-specific structures are computed by using linguistic and structural comparison. The calculated values are used to create necessary mappings.


2019 ◽  
Vol 68 (1) ◽  
pp. 51-77
Author(s):  
Przemysław Rodwald ◽  
Witold Sobolewski ◽  
Maja Rodwald

The aim of this article is to show how one can deanonymize users of cryptocurrencies. To this end the most popular of the cryptocurrencies, i.e. bitcoin is used as an example. At the beginning, the basic concepts about cryptocurrencies are presented. Afterwards, our approach to systematize the types of transactions existing in the blockchain is proposed. This part is enriched with the graphs showing their quantitative occurrence in the blockchain. The main part of this article presents the heuristics use to deanonymize users. A few practical pieces of advice for implementation of the presented heuristics in the real deanonymizing system are included. Then the real case studies are introduced. They are supported with comments based on the experience from court trials carried out by the authors. The final part contains legal regulations and existing tools supporting the deanonymizing process. Keywords: deanonymization, cryptocurrency, bitcoin.


2010 ◽  
pp. 894-928 ◽  
Author(s):  
Robert Wrembel

Methods of designing a data warehouse (DW) usually assume that its structure is static. In practice, however, a DW structure changes among others as the result of the evolution of external data sources and changes of the real world represented in a DW. The most advanced research approaches to this problem are based on temporal extensions and versioning techniques. This article surveys challenges in designing, building, and managing data warehouses whose structure and content evolve in time. The survey is based on the so-called Multiversion Data Warehouse (MVDW). In details, this article presents the following issues: the concept of the MVDW, a language for querying the MVDW, a framework for detecting changes in data sources, a structure for sharing data in the MVDW, index structures for indexing data in the MVDW.


2020 ◽  
Vol 10 (15) ◽  
pp. 5335
Author(s):  
Kathleen Keogh ◽  
Liz Sonenberg

We address the challenge of multi-agent system (MAS) design for organisations of agents acting in dynamic and uncertain environments where runtime flexibility is required to enable improvisation through sharing knowledge and adapting behaviour. We identify behavioural features that correspond to runtime improvisation by agents in a MAS organisation and from this analysis describe the OJAzzIC meta-model and an associated design method. We present results from simulation scenarios, varying both problem complexity and the level of organisational support provided in the design, to show that increasing design time guidance in the organisation specification can enable runtime flexibility afforded to agents and improve performance. Hence the results demonstrate the usefulness of the constructs captured in the OJAzzIC meta-model.


2021 ◽  
Vol 2021 (169) ◽  
pp. 65-77
Author(s):  
Jennifer Brown Urban ◽  
Miriam R. Linver ◽  
Lisa M. Chauveron ◽  
Thomas Archibald ◽  
Monica Hargraves ◽  
...  

2021 ◽  
pp. 027836492098785
Author(s):  
Julian Ibarz ◽  
Jie Tan ◽  
Chelsea Finn ◽  
Mrinal Kalakrishnan ◽  
Peter Pastor ◽  
...  

Deep reinforcement learning (RL) has emerged as a promising approach for autonomously acquiring complex behaviors from low-level sensor observations. Although a large portion of deep RL research has focused on applications in video games and simulated control, which does not connect with the constraints of learning in real environments, deep RL has also demonstrated promise in enabling physical robots to learn complex skills in the real world. At the same time, real-world robotics provides an appealing domain for evaluating such algorithms, as it connects directly to how humans learn: as an embodied agent in the real world. Learning to perceive and move in the real world presents numerous challenges, some of which are easier to address than others, and some of which are often not considered in RL research that focuses only on simulated domains. In this review article, we present a number of case studies involving robotic deep RL. Building off of these case studies, we discuss commonly perceived challenges in deep RL and how they have been addressed in these works. We also provide an overview of other outstanding challenges, many of which are unique to the real-world robotics setting and are not often the focus of mainstream RL research. Our goal is to provide a resource both for roboticists and machine learning researchers who are interested in furthering the progress of deep RL in the real world.


2013 ◽  
Vol 67 (11) ◽  
pp. 2576-2581 ◽  
Author(s):  
A. K. Sharma ◽  
S. Cook ◽  
M. N. Chong

Decentralised water and wastewater systems are being implemented to meet growing demand for municipal services either in combination with centralised systems or as standalone systems. In Australia, there has been increased investment in decentralised water and wastewater systems in response to the capacity constraints of existing centralised systems, an extended period of below average rainfall, uncertainly in traditional water sources due to potential climate change impacts, and the need to reduce the environmental impact of urban development. The implementation of decentralised water systems as a mainstream practice at different development scales is impeded by the knowledge gaps on their actual performance in a range of development types and settings. As the wide-spread uptake of these approaches in modern cities is relatively new compared to centralised approaches, there is limited information available on their planning, design, implementation, reliability and robustness. This paper presents a number of case studies where monitoring studies are under way to validate the performance of decentralised water and wastewater systems. The results from these case studies show the yield and reliability of these decentralised systems, as well as the associated energy demand and ecological footprint. The outputs from these case studies, and other monitoring studies, are important in improving decentralised system design guidelines and developing industry wide management norms for the operation and maintenance of decentralised systems.


2017 ◽  
Vol 107 (04) ◽  
pp. 231-234
Author(s):  
K. Erlach ◽  
E. Sheehan ◽  
S. Hartleif

In der Stückgutindustrie lassen sich die acht Gestaltungsrichtlinien der Wertstrommethode nach Erlach hervorragend anwenden. In der Prozessindustrie weist die Produktion jedoch häufig andere Merkmale (beispielsweise eine Kuppelproduktion) auf, die neue Herausforderungen an die Wertstrommethode stellen. Aufbauend auf den acht Gestaltungsrichtlinien des Wertstromdesigns werden in diesem Fachbeitrag Handlungsempfehlungen für die Anwendung der Wertstrommethode in der Prozessindustrie diskutiert.   The eight design guidelines of Erlach‘s Value Stream Design Method work well in streamlining operations in the piece-good industry. In the process and chemical industries, however, production systems exhibit different characteristics, like joint production, that present challenges for the eight step value stream design method. Building on the eight design guidelines, this article discusses the deficits of this method in the process industries and gives recommendations for its adaptatio.


2015 ◽  
Vol 74 (1) ◽  
Author(s):  
Muhammad Zaki Mustapa

This paper discusses on attitude control of a quadcopter unmanned aerial vehicle (UAV) in real time application. Newton-Euler equation is used to derive the model of system and the model characteristic is analyzed. The paper describes the controller design method for the hovering control of UAV automatic vertical take-off system. In order to take-off the quadcopter and stable the altitude, PID controller has been designed. The scope of study is to develop an altitude controller of the vertical take-off as realistic as possible. The quadcopter flight system has nonlinear characteristics. A simulation is conducted to test and analyze the control performance of the quadcopter model. The simulation was conducted by using Mat-lab Simulink. On the other hand, for the real time application, the PCI-1711 data acquisition card is used as an interface for controller design which routes from Simulink to hardware. This study showed the controller designs are implemented and tuned to the real system using Real Time Windows Target approach by Mat-Lab Simulink.


2014 ◽  
Vol 17 (4) ◽  
pp. 319-335 ◽  
Author(s):  
Alessio Cavicchi ◽  
Cristina Santini ◽  
Lucia Bailetti

Purpose – This purpose of this paper is to introduce a research model inspired by the basic principles of experiential research and apply it to the food and beverage industry. Thinkers and doers often do not speak the same language: many scholars have pursued the goal of reducing the gap between academicians and practitioners by introducing new research models or adapting existing ones. Two case studies with wine and olive oil producers illustrate how the model works and highlight its applicability. Background literature is provided to support the model. Design/methodology/approach – In defining the model, we have followed several steps. First, we searched the literature to identify research needs and insights that might be useful in formulating the model. Second, we constructed a model following some procedural steps suggested in the literature. Third, we tested a model to verify its applicability and functionality. The paper is structured as follows: the first section explores the issue of academic–practitioner collaboration to identify the obstacles to effective collaboration and to define possible benefits from reducing the gap. The second section presents background literature on methodologies for enhancing cross-profession collaboration. Finally, the model is described and two case studies are described to flesh out how the model works. Findings – According to our experience and research results, this model is, paraphrasing Phillips (1987), “warrantable” because it proposes continuous reflection to improve the alignment between thinkers and doers: this method of conducting research is objective and bridges the gap between researchers and practitioners. Because this model centres on experience, participant behaviours and beliefs can be elicited about a host of nondurable goods. Having entrepreneurs put themselves in the consumers’ position, and providing them the results of their experiment can be considered the real value added of this approach. The model proposed in this paper opens a wider perspective in qualitative research, and the two case studies demonstrate that it is particularly flexible for adaptation to various businesses. Research limitations/implications – More case studies could be useful to demonstrate the validity of this model. Particularly, a longitudinal case study aiming at collecting data about the participants’ feedback in the long run could help in understanding the deep value of the proposed model. Practical implications – While this paper illustrates two applications of the model with entrepreneurs and managers of the wine and olive oil industry, this model offers potential for analysis not only in the food and beverage sector but all fast-moving consumer goods sectors, as it can be adapted to techniques other than sensory analysis once researchers have confirmed that they fit with the aim of the research and the peculiarities of the problem observed. Social implications – Tools and methodologies must be chosen according to the type of business the problem refers to, and, while this presents a considerable challenge in organizing ad hoc research teams, it also offers an opportunity for an interdisciplinary approach and an exchange of knowledge and skills from different research fields. In this case, the choice of research methodology is much more driven by the real needs that emerge from the phenomenon observed, rather than by the researchers’ specific skills. Originality/value – This paper has helped us broaden our perspective on research and has encouraged us to reflect on critical issues such as validity of a research process and usefulness of research. Some questions about the role of research in relation to practitioners are still open, but we think that this work has the merit of further highlighting the importance of bridging the gap between researchers and practitioners during research, and the usefulness being flexible and open-minded when carrying out an investigation.


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