Methods of Database Schema Transformations in Support of the Information System Reengineering Process

Cilj istraživanja realizovanih u ovom radu, bio je je da se formalno opišu mogući pristupi transformacijama različitih opisa baza podataka iz jednog modela podataka u drugi i praktično provere kroz njihovu implementaciju u okviru jednog CASE alata, namenjenog projektovanju informacionih sistema i baza podataka. U skladu sa postavljenim ciljem definisan je metodološki pristup i softversko okruženje IIS*Ree koje omogućava visok nivo automatizacije procesa reinženjeringa informacionih sistema. Okruženje IIS*Ree, zasnovano na MDSD principima, kao krajnji rezultat generiše šemu baze podataka u izabranom ciljnom, konceptualnom ili implementacionom modelu podataka, kao i prototip aplikacije.The goal of the research presented in this paper is to formally specify approaches to transformation of database specifications between different data models. The transformations are then to be implemented and tested using a CASE tool for modelling information systems and databases. Following this goal, a methodological approach is defined together with a software named IIS*Ree that provides a high level of automation of the information system reengineering process. The IIS*Ree software, developed in accordance to MDSD principles, generates database schemas specified in a target, conceptual or implementation data model, as well as application prototypes

Methods of Database Schema Transformations in Support of the Information System Reengineering Process

Cilj istraživanja realizovanih u ovom radu, bio je je da se formalno opišu mogući pristupi transformacijama različitih opisa baza podataka iz jednog modela podataka u drugi i praktično provere kroz njihovu implementaciju u okviru jednog CASE alata, namenjenog projektovanju informacionih sistema i baza podataka. U skladu sa postavljenim ciljem definisan je metodološki pristup i softversko okruženje IIS*Ree koje omogućava visok nivo automatizacije procesa reinženjeringa informacionih sistema. Okruženje IIS*Ree, zasnovano na MDSD principima, kao krajnji rezultat generiše šemu baze podataka u izabranom ciljnom, konceptualnom ili implementacionom modelu podataka, kao i prototip aplikacije.The goal of the research presented in this paper is to formally specify approaches to transformation of database specifications between different data models. The transformations are then to be implemented and tested using a CASE tool for modelling information systems and databases. Following this goal, a methodological approach is defined together with a software named IIS*Ree that provides a high level of automation of the information system reengineering process. The IIS*Ree software, developed in accordance to MDSD principles, generates database schemas specified in a target, conceptual or implementation data model, as well as application prototypes

Preface

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Analysis Framework for Reduced Data Warehouse

International audienceOur aim is to define a framework supporting analysis in MDW with reductions. Firstly, we describe a modeling solution for reduced MDW. A schema of reduced MDW is composed of states. Each state is defined as a star schema composed of one fact and its related dimensions valid for a certain period of time. Secondly, we present a multi-state analysis framework. Extensions of classical drilldown and rollup operators are defined to support multi-states analyses. Finally we present a prototype of our framework aiming to prove the feasibility of concept. By implementing our extended operators, the prototype automatically generates appropriate SQL queries over metadata and reduced data

Proceedings of the 4th Workshop of the MPM4CPS COST Action

Proceedings of the 4th Workshop of the MPM4CPS COST Action with the presentations delivered during the workshop and papers with extended versions of some of them

Ontology-based access to temporal data with Ontop: a framework proposal

Predictive analysis gradually gains importance in industry. For instance, service engineers at Siemens diagnostic centres unveil hidden knowledge in huge amounts of historical sensor data and use it to improve the predictive systems analysing live data. Currently, the analysis is usually done using data-dependent rules that are specific to individual sensors and equipment. This dependence poses significant challenges in rule authoring, reuse, and maintenance by engineers. One solution to this problem is to employ ontology-based data access (OBDA), which provides a conceptual view of data via an ontology. However, classical OBDA systems do not support access to temporal data and reasoning over it. To address this issue, we propose a framework for temporal OBDA. In this framework, we use extended mapping languages to extract information about temporal events in the RDF format, classical ontology and rule languages to reflect static information, as well as a temporal rule language to describe events. We also propose a SPARQL-based query language for retrieving temporal information and, finally, an architecture of system implementation extending the state-of-the-art OBDA platform Ontop

Pristup integraciji tehničkih prostora zasnovan na preslikavanjima iinženjerstvu vođenom modelima

In order to automate development of integration adapters in industrial settings, a model-driven approach to adapter specification is devised. In this approach, a domain-specific modeling language is created to allow specification of mappings between integrated technical spaces. Also proposed is the mapping automation engine that comprises reuse and alignment algorithms. Based on mapping specifications, executable adapters are automatically generated and executed. Results of approach evaluations indicate that it is possible to use a model-driven approach to successfully integrate technical spaces and increase the automation by reusing domainspecific mappings from previously created adapters.За потребе повећања степена аутоматизације развоја адаптера за интеграцију у индустријском окружењу, осмишљен је моделом вођен приступ развоју адаптера. У оквиру овог приступа развијен је наменски језик за спецификацију пресликавања између техничких простора који су предмет интеграције. Приступ обухвата и алгоритме за поравнање и поновно искориштење претходно креираних пресликавања са циљем аутоматизације процеса спецификације. На основу креираних пресликавања, могуће je аутоматски генерисати извршиви код адаптера. У испитивањима приступа, показано је да је могуће успешно применити моделом вођен приступ у интеграцији техничких простора као и да је могуће успешно повећати степен аутоматизације поновним искоришћењем претходно креираних пресликавања.Za potrebe povećanja stepena automatizacije razvoja adaptera za integraciju u industrijskom okruženju, osmišljen je modelom vođen pristup razvoju adaptera. U okviru ovog pristupa razvijen je namenski jezik za specifikaciju preslikavanja između tehničkih prostora koji su predmet integracije. Pristup obuhvata i algoritme za poravnanje i ponovno iskorištenje prethodno kreiranih preslikavanja sa ciljem automatizacije procesa specifikacije. Na osnovu kreiranih preslikavanja, moguće je automatski generisati izvršivi kod adaptera. U ispitivanjima pristupa, pokazano je da je moguće uspešno primeniti modelom vođen pristup u integraciji tehničkih prostora kao i da je moguće uspešno povećati stepen automatizacije ponovnim iskorišćenjem prethodno kreiranih preslikavanja

Role-Based Access-Control for Databases

Liikudes üha enam paberivaba ari suunas, hoitakse üha enam tundlikku informatsiooni andmebaasides. Sellest tulenevalt on andmebaasid ründajatele väärtuslik sihtmärk. Levinud meetod andmete kaitseks on rollipõhine ligipääsu kontroll (role-based access control), mis piirab süsteemi kasutajate õiguseid vastavalt neile omistatud rollidele. Samas on turvameetmete realiseerimine arendajate jaoks aeganõudev käsitöö, mida teostatakse samaaegselt rakenduse toimeloogika realiseerimisega. Sellest tulenevalt on raskendatud turva vajaduste osas kliendiga läbirääkimine projekti algfaasides. See omakorda suurendab projekti reaalsete arenduskulude kasvamise riski, eriti kui ilmnevad turvalisuse puudujäägid realisatsioonis. Tänapäeva veebirakendustes andmebaasi ühenduste puulimine (connec-tion pooling ), kus kasutatakse üht ja sama ühendust erinevate kasutajate teenindamiseks, rikub vähima vajaliku õiguse printsiipi. Kõikidel ühendunud kasutajatel on ligipääs täpselt samale hulgale andmetele, mille tulemusena võib lekkida tundlik informatsioon (näiteks SQLi süstimine (SQL injection ) või vead rakenduses). Lahenduseks probleemile pakume välja vahendid rollipõhise ligipääsu kontorolli disainimiseks tarkvara projekteerimise faasis. Rollipõhise ligipääsu kontorolli modelleerimiseks kasutame UML'i laiendust SecureUML. Antud mudelist on võimalik antud töö raames valminud vahenditega genereerida koodi, mis kontrollib ligipääsu õiguseid andmebaasi tasemel. Antud madaltasemekontroll vähendab riski, et kasutajad näevad andmeid, millele neil ligipääsu õigused puuduvad. Antud töös läbiviidud uuring näitas, et mudelipõhine turvalisuse arendamise kvaliteet on kõrgem võrreldes programmeerijate poolt kirjutatud koodiga. Kuna turvamudel on loodud projekteerimise faasis on selle semantiline täielikkus ja korrektsus kõrge, millest tulenevalt on seda kerge lugeda ja muuta ning seda on lihtsam kasutada arendajate ja klientide vahelises suhtluses.With the constant march towards a paperless business environment, database systems are increasingly being used to hold more and more sensitive information. This means they present an increasingly valuable target for attackers. A mainstream method for information system security is Role-based Access Control (RBAC), which restricts system access to authorised users. However the implementation of the RBAC policy remains a human intensive activity, typically, performed at the implementation stage of the system development. This makes it difficult to communicate security solutions to the stakeholders earlier and raises the system development cost, especially if security implementation errors are detected. The use of connection pooling in web applications, where all the application users connect to the database via the web server with the same database connection, violates the the principle of minimal privilege. Every connected user has, in principle, access to the same data. This may leave the sensitive data vulnerable to SQL injection attacks or bugs in the application. As a solution we propose the application of the model-driven development to define RBAC mechanism for data access at the design stages of the system development. The RBAC model created using the SecureUML approach is automatically translated to source code, which implements the modelled security rules at the database level. Enforcing access-control at this low level limits the risk of leaking sensitive data to unauthorised users. In out case study we compared SecureUML and the traditional security model, written as a source code, mixed with business logic and user-interface statements. The case study showed that the model-driven security development results in significantly better quality for the security model. Hence the security model created at the design stage contains higher semantic completeness and correctness, it is easier to modify and understand, and it facilitates a better communication of security solutions to the system stakeholders than the security model created at the implementation stage

Reprezentacije i metrike za mašinsko učenje i analizu podataka velikih dimenzija

In the current information age, massive amounts of data are gathered, at a rate prohibiting their effective structuring, analysis, and conversion into useful knowledge. This information overload is manifested both in large numbers of data objects recorded in data sets, and large numbers of attributes, also known as high dimensionality. This dis-sertation deals with problems originating from high dimensionality of data representation, referred to as the “curse of dimensionality,” in the context of machine learning, data mining, and information retrieval. The described research follows two angles: studying the behavior of (dis)similarity metrics with increasing dimensionality, and exploring feature-selection methods, primarily with regard to document representation schemes for text classification. The main results of the dissertation, relevant to the first research angle, include theoretical insights into the concentration behavior of cosine similarity, and a detailed analysis of the phenomenon of hubness, which refers to the tendency of some points in a data set to become hubs by being in-cluded in unexpectedly many k-nearest neighbor lists of other points. The mechanisms behind the phenomenon are studied in detail, both from a theoretical and empirical perspective, linking hubness with the (intrinsic) dimensionality of data, describing its interaction with the cluster structure of data and the information provided by class la-bels, and demonstrating the interplay of the phenomenon and well known algorithms for classification, semi-supervised learning, clustering, and outlier detection, with special consideration being given to time-series classification and information retrieval. Results pertaining to the second research angle include quantification of the interaction between various transformations of high-dimensional document representations, and feature selection, in the context of text classification.U tekućem „informatičkom dobu“, masivne količine podataka se sakupljaju brzinom koja ne dozvoljava njihovo efektivno strukturiranje, analizu, i pretvaranje u korisno znanje. Ovo zasićenje informacijama se manifestuje kako kroz veliki broj objekata uključenih u skupove podataka, tako i kroz veliki broj atributa, takođe poznat kao velika dimenzionalnost. Disertacija se bavi problemima koji proizilaze iz velike dimenzionalnosti reprezentacije podataka, često nazivanim „prokletstvom dimenzionalnosti“, u kontekstu mašinskog učenja, data mining-a i information retrieval-a. Opisana istraživanja prate dva pravca: izučavanje ponašanja metrika (ne)sličnosti u odnosu na rastuću dimenzionalnost, i proučavanje metoda odabira atributa, prvenstveno u interakciji sa tehnikama reprezentacije dokumenata za klasifikaciju teksta. Centralni rezultati disertacije, relevantni za prvi pravac istraživanja, uključuju teorijske uvide u fenomen koncentracije kosinusne mere sličnosti, i detaljnu analizu fenomena habovitosti koji se odnosi na tendenciju nekih tačaka u skupu podataka da postanu habovi tako što bivaju uvrštene u neočekivano mnogo lista k najbližih suseda ostalih tačaka. Mehanizmi koji pokreću fenomen detaljno su proučeni, kako iz teorijske tako i iz empirijske perspektive. Habovitost je povezana sa (latentnom) dimenzionalnošću podataka, opisana je njena interakcija sa strukturom klastera u podacima i informacijama koje pružaju oznake klasa, i demonstriran je njen efekat na poznate algoritme za klasifikaciju, semi-supervizirano učenje, klastering i detekciju outlier-a, sa posebnim osvrtom na klasifikaciju vremenskih serija i information retrieval. Rezultati koji se odnose na drugi pravac istraživanja uključuju kvantifikaciju interakcije između različitih transformacija višedimenzionalnih reprezentacija dokumenata i odabira atributa, u kontekstu klasifikacije teksta