Database Systems Journal

ISSN 2069 - 3230

Published with the support of:
The Bucharest University of Economic Studies


Database Systems Journal, Vol. XI, 2020


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CONTENTS


1. Operational Research in the Emergency Medical System of Romania (p. 3-13)
Ionut NICA, The Bucharest University of Economic Studies, Romania
The explosive development of the human society in contrast to the limited character of resources determines the need for successful implementation of mathematic models in the decision-making process concerning the use of available resources. One of the critical areas where the need for rigorous criteria for resource allocation is strongly felt is the medical field. This issue appears to be currently affecting the great majority of nations in the world, being considered one of the most important challenges for modern states. The limited amount of resources allocated to the medical system brings forward the importance of optimizing the decision-making process concerning this field using models able to reflect the increasing complexity of the medical system, its interactions with the human society and its dynamics, therefore providing the perturbation control and adjustment instruments. From this point of view, the economical and mathematical modeling of the social phenomena provides strong, elegant and rigorous tools for the description of medical system that appears to be organized as a cybernetic system with a high level of complexity, focused on maximizing the social utility, and allowing the use of cybernetic methods designed for diagnosing, developing automatic medical archives, reducing time consumption and increasing overall efficiency.
Keywords: Markov network, Poisson distribution, cybernetics models, optimal decision, emergency medical system
2. Business Analytics Applications for Consumer Credits (p. 14-23)
Claudia ANTAL_VAIDA, The Bucharest University of Economic Studies, Romania
The fast-paced and dynamic economical background determines all the industries to quickly adapt to change and adopt emerging technologies to remain competitive on the market. This tendency led to high volumes of data generated each second and to a decreasing ability of the manpower to analyze it and use if for beneficial purposes. This paper reviews the impact of Digital Transformation on the Banking area and how financial institutions leverage the advantage created by this trend, especially in the credit risk management field. Multiple papers on consumer credit scoring models written after the financial crisis from 2007 were reviewed and their results were summarized in this article, to increase the accuracy of future analysis by leveraging the already known results.
Keywords: Business Analytics, Machine Learning, Banking, Credit Risk Assessment, Scoring Models, Consumer Credits
3. Business Intelligence and Machine Learning. Integrated cloud solutions providing business insights for decision makers. (p. 24-36)
Laura-Gabriela TANASESCU, The Bucharest University of Economic Studies, Romania
The aim of this paper is to present the latest trends in business intelligence and ways in which nowadays organizations can implement cloud technologies. This work is going to present challenges of the market, providers of integrated cloud business intelligences tools, advantages and disadvantages of moving to the cloud. A real life use case will argue the importance of taking advantage of data, as well as the necessity and the obvious benefits of having the right tools of transforming data into correct business decisions.
Keywords: business intelligence, cloud computing, artificial intelligence, analytics, machine learning, innovation, data
5. A Big Data Modeling Methodology for NoSQL Document Databases (p. 37-46)
Gerardo ROSSEL, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
Andrea MANNA, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
In recent years, there has been an increasing interest in the field of non-relational databases. However, far too little attention has been paid to design methodology. Key-value datastores are an important component of a class of non-relational technologies that are grouped under the name of NoSQL databases. The aim of this paper is to propose a design methodology for this type of database that allows overcoming the limitations of the traditional techniques. The proposed methodology leads to a clean design that also allows for better data management and consistency
Keywords: NoSQL, Document Databases, Conceptual Modeling, Data Modeling, NoSQL Database developing
5. Learning view over the implementation of business process optimizations (p. 47-57)
Radu SAMOILA, The Bucharest University of Economic Studies, Romania
Current context of great development and changes in the technological matters, national and global economies have to keep pace and undergone major changes. The ultimate aim of the companies and organization is to improve or optimize its business processes to cope with increased competitiveness in order to deliver more efficiently better products or services. The success of current businesses is linked to the efficiency but also the effectiveness of their core processes. Most part of the latest researches have recognized this importance leading to efforts concentrated on analyzing and optimizing the business processes. There are many techniques which are considered but also others which are not causing potentially significant opportunities of improvement not being addressed. However, currently, there is a scarce of an universal technique or methodology that can be used by the organizations to address business optimizations. This paper addresses different topics on how companies are analyzing the decision to initiate a business process optimization and how optimizations landed within organizations.
Keywords: business process, optimization, efficiency and effectiveness of internal processes, business automation, optimization methodology
6. Natural Learning Processing based on Machine Learning Model for automatic analysis of Online Reviews related to Hotels and Resorts (p. 58-77)
Bogdan-Stefan POSEDARU, The Bucharest University of Economic Studies, Romania
Tiberiu-Marian GEORGESCU, The Bucharest University of Economic Studies, Romania
Florin-Valeriu PANTELIMON, The Bucharest University of Economic Studies, Romania
This article describes the development and implementation of a natural language processing (NLP) model based on machine learning (ML) for automatic analysis of customers' reviews on hotels and resorts written in English. The model performs named entity recognition (NER), relation extraction (RE) as well as sentiment analysis (SA). The performance indicators validate the model, as we obtained an F1 score of 0.79 for ER and 0.61 for RE. Our results prove to be remarkable compared to other models that use similar techniques and technologies. Furthermore, we developed a web application which allows users to benefit from our model to automatically analyze customers' reviews about hotels and resorts.
Keywords: Natural Language Processing, Machine Learning, Entity Recognition, Relation Extraction, Sentiment Analysis
7. Application for the efficiency improvement of the work process in an energy company (p. 78-89)
Madalina-Florina DANALACHE, The Bucharest University of Economic Studies, Romania
Simona-Vasilica OPREA, The Bucharest University of Economic Studies, Romania
In modern society, electricity is necessary for the proper conduct of daily activities, becoming es-sential for life. All existing domains such as industry, transport, information technology, agricultu-re, economy, etc. requires energy resources to carry out the activities undertaken in optimal condi-tions. Thus, distribution companies invest enormously to transform networks into smart grids thro-ugh a digitization effort that is constantly supported by modernization projects. As an alternative with lower costs, an application can be implemented that helps consumers and employees regarding the the continuity of electricity supply, the quality of services provided to them and better communication between the consumer and the distribution operator.
Keywords: electricity distribution company, consumer satisfaction, web application, prompt and quality services, automation of daily activities, easy reporting
8. The influence of art upon the feeling of life fulfilment (p. 90-98)
Iuliana COMAN, The Bucharest University of Economic Studies, Romania
The aim of this paper is to analyse the influence of art upon the feeling of life fulfilment and the participation of art to the consolidation of the community. The analysis is performed using data obtained from an experimental study on a sample of 120 persons with higher education in the south of Romania. Data were analysed using SPSS and Microsoft Excel and contain descriptive tables. The analysis took into consideration the comparison of the results obtained using a variety of statistical methods. Following the analysis, it was concluded that the presence of art both influence the feeling of life fulfilment and contributes to the consolidation of the community.
Keywords: Art, Society, Statistics
9. Exploiting stack-based buffer overflow using modern-day techniques (p. 99-108)
Stefan NICULA, The Bucharest University of Economic Studies, Romania
Razvan Daniel ZOTA, The Bucharest University of Economic Studies, Romania
One of the most commonly known vulnerabilities that can affect a binary executable is the stack-based buffer overflow. The buffer overflow occurs when a program, while writing data to a buffer, overruns the buffer's boundary and overwrites adjacent memory locations. Nowadays, due to multiple protection mechanisms enforced by the operating systems, the buffer overflow has become harder to exploit. Multiple bypassing techniques are often required to be used in order to successfully exploit the vulnerability and control the execution flow of the analysed executable. One of the security features designed as protection mechanisms is Data Execution Prevention (DEP) which helps prevent code execution from the stack, heap or memory pool pages by marking all memory locations in a process as non-executable unless the location explicitly contains executable code. Another protection mechanism targeted is the Address Space Layout Randomization (ASLR), which is often used in conjunction with DEP. This security feature randomizes the location where the system executables are loaded into memory. By default, modern-day operating systems have these security features implemented. However, on the executable level, they have to be explicitly enabled. Most of the protection mechanisms, like the ones mentioned above, require certain techniques in order to bypass them and many of these techniques are using some form of address memory leakage in order to leverage an exploit. By successfully exploiting a buffer overflow, the adversary can potentially obtain code execution on the affected operating system which runs the vulnerable executable. The level of the privilege granted to the adversary is highly depended on the level of privilege that the binary is executed with. As such, an adversary may gain elevated privileges inside the system. Most of the time, this type of vulnerability is used for privilege escalation attacks or for gaining remote code execution on the system.
Keywords: stack buffer overflow, return-oriented programming, libc attack, exploiting buffer overflow, stack protection mechanisms, address memory leak
10. Big Data Analytics in Smart Grids (p. 109-116)
Filip FEDELES, Bucharest, Romania
Ionut TARANU, Bucharest, Romania
Data analytics are now playing a more important role in the modern industrial systems. Driven by the development of information and communication technology, an information layer is now added to the conventional electricity transmission and distribution network for data collection, storage and analysis with the help of wide installation of smart meters and sensors. Big data has a potential to unlock novel groundbreaking opportunities in the power grid sector that enhances a multitude of technical, social, and economic gains. The currently untapped potential of applying the science of big data for better planning and operation of the power grid is a very challenging task and needs significant efforts all-around. As power grid technologies evolve in conjunction with measurement and communication technologies, this results in unprecedented amount of heterogeneous big data sets from diverse sources
Keywords: big data analytics, smart grid
11. The Digital Transformation and Disruption in Business Models of the Banks under the Impact of FinTech and BigTech (p. 117-127)
Oona VOICAN, The Bucharest University of Economic Studies, Romania
The explosive development of artificial intelligence, machine learning and big data methods in the last 10 years has been felt in the financial-banking field which has subjected to profound changes aimed at determining an unprecedented increase in the efficiency and profitability of the businesses they carry out. The tendencies of applying the concepts coming from AI, together with the continuous increase of the volume, complexity and variety of the data that the banks collect, store and process have acquired the generic names of FinTech, respectively BigTech. Five main areas exist where FinTech and BigTech can provide improvements in business models for the banks: introducing specialized platforms, covering neglected customer segments, improving customer selection, reduction of the operating costs of the banks, and optimization of the business processes of the banks. We will present some of these improvements, and then we will show how the business models of the banks dramatically transform under the influence of these changes.
Keywords: Artificial intelligence, BigTech, Business models, Digital transformation, FinTech

Database Systems Journal, 2020
Special issue: Software solutions for efficient trading on the electricity markets


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CONTENTS


1. Testing Approaches for an Electricity Market Simulator (p. 3-16)
Anca Ioana ANDREESCU, The Bucharest University of Economic Studies, Romania
Ana Ramona BOLOGA, The Bucharest University of Economic Studies, Romania
Software testing methodologies represent different approaches and techniques to ensure that a particular software application is fully tested. This paper addresses the functional testing of a software system for simulating electricity markets. The tested functionalities are briefly presented and the main testing techniques compatible with this type of system are analyzed. The purpose is to recommend the best combination of techniques recommended in this case and to present results obtained by applying them to the simulator.
Keywords: functional testing technics, behavioral testing, electricity market, simulator
2. Dashboard for analysis of electricity imbalances at the Balancing Responsible Parties level (p. 17-30)
Simona-Vasilica OPREA, The Bucharest University of Economic Studies, Romania
Adela BARA, The Bucharest University of Economic Studies, Romania
Ciprian Georgian DRAGOMIR, CEZ Romania
Osman Bulent TOR, EPRA, Engineering Procurement Research Analysis, Ankara, Turkey
Stefan PREDA, The Bucharest University of Economic Studies, Romania
The paper presents the Dashboard for the analysis of imbalances at the level of a Balancing Responsible Party BRP (ABI-PRE). It describes the allocation between the members of a BRP of the costs/revenues generated by the net imbalances of the respective BRP and the calculation methodology implemented within the IT prototype. The reports created within the ABI-PRE Dashboard are generated following the analysis of specific indicators (contribution of BRP members to imbalances, revenues/expenses resulting from internal redistribution, additional revenues/expenses from system balancing, share of imbalance at BRP level, ratios between adjusted average prices and average prices on the Balancing Market) and BRP performance (BRP efficiency).
Keywords: balancing market, balancing responsible parties, surplus, deficit, cost allocation method
3. Consumption Management Software for Electric Power Suppliers (p. 31-40)
Ana-Ramona BOLOGA, The Bucharest University of Economic Studies, Romania
Simona-Vasilica OPREA, The Bucharest University of Economic Studies, Romania
Adela BARA, The Bucharest University of Economic Studies, Romania
Florin-Constantin CIOBANU, CEZ Romania
Osman Bulent TOR, EPRA, Engineering Procurement Research Analysis, Ankara, Turkey
The electricity market is a very complex reality, with numerous participants, rules, factors that influence the evolution of energy production and consumption. This paper presents a software solution that supports electric power suppliers as participants in this complex market. The prototype uses machine learning algorithms to determine consumer clusters and forecast the next day's consumption, the purpose being to obtain the flattening of the consumption curve at the level of the electricity supplier. Based on the initial consumption planning of programmable devices transmitted by consumers, four consumption optimization algorithms are applied in parallel, giving the energy supplier the possibility to decide the optimal plan for the next day.
Keywords: power sector, software, power suppliers, forecast, optimization
4. Electricity Consumption Management Software Tool for Consumers - MY SMART HOME (p. 41-53)
Anca ANDREESCU, The Bucharest University of Economic Studies, Romania
Adela BARA, The Bucharest University of Economic Studies, Romania
Simona-Vasilica OPREA, The Bucharest University of Economic Studies, Romania
George Adrian IFRIM, "Dunarea de Jos" University, Department of Automatic control and Electrical Engineering , Galati, Romania
Osman Bulent TOR, EPRA, Engineering Procurement Research Analysis, Ankara, Turkey
Andrei BUCUR, Smarte Tech Energy Concept SRL, Bucharest, Romania
In the introductory part, this paper summarizes the main aspects related to smart homes and home energy management (HEM) technologies and presents several existing HEM solutions. The proposed Electricity consumption management software tool for consumers - MY SMART HOME allows the management of the types of devices that facilitate the monitoring and optimization of electricity consumption: meters, smart devices, and sensors. A process for optimal scheduling of the devices was implemented, through a series of seven steps to be followed by the user. Some reporting solutions, both in graphical and tabular form, for analyzing the initial and optimal consumption per device, consumption place and household are offered.
Keywords: power sector, smart homes, software, energy consumption, optimization
5. Data Analytics for the Transmission System Operators (p. 54-73)
Dan PREOTESCU, Romanian Energy Center, Bucharest, Romania
Simona-Vasilica OPREA, The Bucharest University of Economic Studies, Romania
Adela BARA, The Bucharest University of Economic Studies, Romania
Niculae OPREA, Transelectrica S.A., Bucharest, Romania
Osman Bulent TOR, EPRA, Engineering Procurement Research Analysis, Ankara, Turkey
In the beginning the paper briefly presents the worldwide context determined by the global warming phenomenon evolution, and the foreseen impact on the power sector, with the focus on the massive integration of the RES powered electricity generators. Identifying the TSOs and grid operators as the main actors for implementing the necessary changes, the authors of the paper are proposing data analytics, designed to support the TSOs and grid operators in fulfilling their main functions and responsibilities. The structure and the capabilities (analysis and reports) of the software product are presented, including practical examples for usage, and highlighting the potential usefulness of each analyze and/or report, from TSOs and grid operators' point of view.
Keywords: power sector, Renewable Energy Sources, software, Transmission System Operators, grid operator, forecast

Database Systems Journal, 2020
Special issue: Data management and analysis through the eyes of the students


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CONTENTS


1. Usage of IoT in automation routine processes (p. 3-11)
Cornel MIRCESCU, The Bucharest University of Economic Studies, Romania
Internet of Things or IoT is a representation of the automatic processes by integrating processors, sensors and data collections through a huge amount of processing techniques. The contribution of IoT in technology is significant, offering revolutionary changes in a big amount of industries. [1] Actually, these devices became so powerful that they can work with data in real-time, doing machine learning and artificial intelligence. In big words, a single processor got the frequency up to 2.4 GHz, with integrated Wi-Fi and many connectors, for the connection with sensors, being capable of simultaneously working with all of them, depending of the back-end efficiency programming. Initially, the IoT devices were programmable only by the Arduino IDE, which is based on C++. After some time, languages like Python and C# opened their support by creating or opening open-source projects for libraries to work with them, processors being recognized as a programmable mini PC. USB was the only solution for code upload, the IDE doing the compilation and the transfer, then the project could just work with a source of electricity (for smaller projects, a powerbank could be enough). The programming language Python evolved and they released, through a open-source project, OTA (Over The Air) upload, which means the project will need just the usual electricity source and Wi-Fi, no more physical connection to the PC.
Keywords: IoT, big data, database, programming, protocol, sensor, module, upload
2. Multi-user event planning web-application (p. 12-22)
Cristina-Maria GRIGORIE, The Bucharest University of Economic Studies, Romania
Simona-Vasilica OPREA, The Bucharest University of Economic Studies, Romania
Given the fact that we live in a time when everything is surrounded by technology and most of the people are looking for faster and more efficient alternatives regarding their problems, developers must adapt and provide modern solutions. By doing a research, we discovered that event planning is a domain which has not registered any standing out improvements in terms of technology yet. Therefore, in this paper, we propose a web application for making event planning a more efficient process.
Keywords: event planning, efficient, multi-user web application
3. Application assisting tourists with integrated information from certain areas of interest (p. 23-32)
Florina-Daria GAGEA, The Bucharest University of Economic Studies, Romania
Travelling often involves the contact with a wide range of information from many sources. Organizing a vacation in a city like Bucharest, relatively chaotic and quite unfriendly to those who are not familiar with its rhythm and characteristics, especially if they are not Romanian speakers, can be an unpleasant process. Thus, this paper aims to develop an application that will serve as a tool in conducting a vacation in Bucharest in accordance with the needs, desires and preferences indicated by the user. The knowledge and activities of a local tourist guide, the promptness of a personal advisor, the availability of an expert and reliable friend are the activities that will represent the core of the application.