Gramatikov, Sasho
Preferred name
Gramatikov, Sasho
Official Name
Gramatikov, Sasho
Main Affiliation
Email
sasho.gramatikov@finki.ukim.mk
33 results
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Item type:Publication, Learning Robust Food Ontology Alignment(IEEE, 2022-12-17) ;Mijalcheva, Viktorija ;Davcheva, Ana; ; In today’s knowledge society, large number of information systems use many different individual schemes to represent data. Ontologies are a promising approach for formal knowledge representation and their number is growing rapidly. The semantic linking of these ontologies is a necessary prerequisite for establishing interoperability between the large number of services that structure the data with these ontologies. Consequently, the alignment of ontologies becomes a central issue when building a worldwide Semantic Web. There is a need to develop automatic or at least semi-automatic techniques to reduce the burden of manually creating and maintaining alignments. Ontologies are seen as a solution to data heterogeneity on the Web. However, the available ontologies are themselves a source of heterogeneity. On the Web, there are multiple ontologies that refer to the same domain, and with that comes the challenge of a given graph-based system using multiple ontologies whose taxonomy is different, but the semantics are the same. This can be overcome by aligning the ontologies or by finding the correspondence between their components.In this paper, we propose a method for indexing ontologies as a support to a solution for ontology alignment based on a neural network. In this process, for each semantic resource we combine the graph based representations from the RDF2vec model, together with the text representation from the BERT model in order to capture the semantic and structural features. This methodology is evaluated using the FoodOn and OntoFood ontologies, based on the Food Onto Map alignment dataset, which contains 155 unique and validly aligned resources. Using these limited resources, we managed to obtain accuracy of 74% and F1 score of 75% on the test set, which is a promising result that can be further improved in future. Furthermore, the methodology presented in this paper is both robust and ontology-agnostic. It can be applied to any ontology, regardless of the domain. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Semantic Sky: A Gmail Plugin for Email Classification and Annotation(2024-04) ;Osmani, Agon ;Jovanovik, Milos; - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Learning Robust Food Ontology Alignment(2023-01-26) ;Mijalcheva, Viktorija ;Davcheva, Ana; ;Jovanovik, MilosIn today’s knowledge society, large number of information systems use many different individual schemes to represent data. Ontologies are a promising approach for formal knowledge representation and their number is growing rapidly. The semantic linking of these ontologies is a necessary prerequisite for establishing interoperability between the large number of services that structure the data with these ontologies. Consequently, the alignment of ontologies becomes a central issue when building a worldwide Semantic Web. There is a need to develop automatic or at least semi-automatic techniques to reduce the burden of manually creating and maintaining alignments. Ontologies are seen as a solution to data heterogeneity on the Web. However, the available ontologies are themselves a source of heterogeneity. On the Web, there are multiple ontologies that refer to the same domain, and with that comes the challenge of a given graph-based system using multiple ontologies whose taxonomy is different, but the semantics are the same. This can be overcome by aligning the ontologies or by finding the correspondence between their components.In this paper, we propose a method for indexing ontologies as a support to a solution for ontology alignment based on a neural network. In this process, for each semantic resource we combine the graph based representations from the RDF2vec model, together with the text representation from the BERT model in order to capture the semantic and structural features. This methodology is evaluated using the FoodOn and OntoFood ontologies, based on the Food Onto Map alignment dataset, which contains 155 unique and validly aligned resources. Using these limited resources, we managed to obtain accuracy of 74% and F1 score of 75% on the test set, which is a promising result that can be further improved in future. Furthermore, the methodology presented in this paper is both robust and ontology-agnostic. It can be applied to any ontology, regardless of the domain. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Analysis and comparative evaluation of front-end technologies for web application development(2022) ;Ilievska, FrosinaIn this dynamic, ever-evolving world of web technology, many development tools are created. Everyone can agree that the programming language JavaScript is already in use and will continue to be popular in the future. Despite the many great JavaScript technologies over the past decade, Angular, React.js, and Vue.js remain the most popular. The construction of a modern single-page application is covered in this study, with an emphasis on the front-end in each of the technologies and the analysis of tests relating to the three key areas of performance, modularity, and usability where data may be evaluated and compared. By analyzing the test findings of the three aspects using the analytical hierarchy process approach, a comparison was produced. This paper provides a response to the question: Which JavaScript framework is best for developing single-page applications in terms of performance, modularity, and usability? In conclusion, React is the most suitable option for a simple single-page frontend application in our case. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Comparing the performance of Text Classification Models for climate change-related texts(Ss Cyril and Methodius University in Skopje, Faculty of Computer Science and Engineering, Republic of North Macedonia, 2023-07) ;Lazarev, Gorgi; This study aims to evaluate and compare the performance of two text classification models specifically tailored for classifying climate change-related texts. The models under investigation are ClimateBert Environmental Claims and ClimateBert Fact Checking, both of which are based on the ClimateBert model and available in the HuggingFace Hub. Our analysis focuses on the impact of fine-tuning these models using specific climate change-related datasets, as well as their performance without fine-tuning. We assess the models using various metrics, including accuracy, precision, recall, and F1 score, and identify the areas where they predominantly make classification errors. Through our findings, we highlight the significance of using these methodologies for the evaluation and comparison of climate change-related text classification models and to appropriately fine-tune the models with context-specific data to achieve optimal classification results. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Popularity based distribution schemes for P2P assisted streaming of VoD contents(Telecomunicacion, 2012); ;Jaureguizar Núñez, Fernando ;Cabrera Quesada, JulianGarcía Santos, NarcisoThe Video on Demand (VoD) service is becoming a dominant service in the telecommunication market due to the great convenience regarding the choice of content items and their independent viewing time. However, it comes with the downsides of high server storage and capacity demands because of the large variety of content items and the high amount of traffic generated for serving each request. Storing part of the popular contents on the peers brings certain advantages but, it still has issues regarding the overall traffic in the core of the network and the scalability. Therefore We propose a P2P assisted model for streaming VoD contents that takes advantage of the clients unused uplink and storage capacity to serve requests of other clients and present popularity based schemes for distribution of both the popular and unpopular contents on the peers with the objective to reduce the streaming traffic in the core of the network, improve the responsiveness of the system and increase its scalability - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Last Mile Delivery with Autonomous Vehicles: Fiction or Reality?(Ss. Cyril and Methodius University in Skopje, Faculty of Computer Science and Engineering, Republic of North Macedonia, 2019-05); ; ; Autonomous vehicles (AVs) are a disruptive technology of the 21-st century that are beginning the next revolution of the transportation of people and goods. Their presence has a particular impact on the future directions of development of E-commerce. The number of online orders is in a steep incline, and so is the necessity to deliver goods to the customer in an efficient and environmental friendly way. Using autonomous drones, pods and vans for delivery of goods has already become reality. But, what is the state of the art of the companies offering these services and how do people feel about it? The aim of this paper is to make an overview of the business models of the companies developing AVs for Last Mile Delivery (LMD) of goods and to find out what is the attitudes of the online customers towards using AVs for delivery of their goods. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Performance Evaluation of Back-end Web Application Programming Languages(Ss Cyril and Methodius University in Skopje, Faculty of Computer Science and Engineering, Republic of North Macedonia, 2023-07) ;Jelikj, IvanThere are many programming languages that can be used for back-end web development. Numerous aspects of the project could be affected by the choice of a language. Because of that, the question about the most suitable programming language for a given web application arises. One of the main aims of this paper is to quantitatively compare 4 programming languages that could be used for back-end software development: Java, Kotlin, PHP and Python. Execution time, RAM usage, and CPU usage were selected as evaluation criteria. In order to be able to compare them, in all 4 given languages an application with the same functionality was created. The measurements were performed in an isolated environment for a different number of requests and different realistic scenarios. From the results it could be concluded that Java and Kotlin have in general better execution time in comparison with PHP and Python, especially with a larger number of requests; Python has the smallest usage of CPU while the other 3 languages have similar usage; the usage of RAM in Python and PHP is significantly smaller than Kotlin and Java. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Named Entity Recognition For Macedonian Language(CIIT 2021, 2021-05-06); ; ; ;Ivan KrstevFisnik DokoNamed Entity Recognition (NER), an outstanding technique for information extraction from unstructured texts, is lately becoming the central problem in the field of Natural Language Processing (NLP). In the last few years, multiple Python libraries, like SpaCy, NLTK and FLAIR, accomplished state-of-the-art performances for this problem. As NER is developing into a powerful technique, its real-live applications are becoming more and more numerous: from customer-message categorization to ease of document analysis in greater corporations. In this research, we use a ML-based system with the help of the FLAIR library in Python, which has already provided optimal results for NER in few world-class languages (English, German, Russian, French etc.), for financial entity recognition in financial texts written in Macedonian language. For the NER task on 13 distinct labels using our dataset in Macedonian language on the proposed ML model we have obtained F1-score of around 0.75. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Multi-horizon air pollution forecasting with deep neural networks(MDPI, 2021-02-10) ;Arsov, Mirche; ; ;Corizzo, RobertoKoteli, NikolaAir pollution is a global problem, especially in urban areas where the population density is very high due to the diverse pollutant sources such as vehicles, industrial plants, buildings, and waste. North Macedonia, as a developing country, has a serious problem with air pollution. The problem is highly present in its capital city, Skopje, where air pollution places it consistently within the top 10 cities in the world during the winter months. In this work, we propose using Recurrent Neural Network (RNN) models with long short-term memory units to predict the level of PM10 particles at 6, 12, and 24 h in the future. We employ historical air quality measurement data from sensors placed at multiple locations in Skopje and meteorological conditions such as temperature and humidity. We compare different deep learning models’ performance to an Auto-regressive Integrated Moving Average (ARIMA) model. The obtained results show that the proposed models consistently outperform the baseline model and can be successfully employed for air pollution prediction. Ultimately, we demonstrate that these models can help decision-makers and local authorities better manage the air pollution consequences by taking proactive measures.
