Gergő Gombos

Eötvös Loránd University · Faculty of Informatics

Novel applications and network scenarios challenge existing traffic management strategies. Hierarchical Quality of Service (HQoS) provides a fine control of resource sharing and delay, but traditional HQoS solutions have challenging complexity that prevents their deployment in the traffic management engine of high-speed switches. Programmable switc...

Resource sharing is of utmost importance in networking environments where substantial overprovisioning is economically infeasible. Different centralized solutions have recently been proposed for Wide Area Networks (WANs), Access Aggregation Networks and other closed networking domains, relying on different ideas from exploiting the capabilities of...

Reinforcement learning has gone through an enormous evolution in the past ten years. It's practical applicability has been demonstrated through several use cases in various fields from robotics to process automation. In this paper, we examine how the tools of deep Q-learning can be used in an AQM algorithm to reduce queuing delay and ensure good li...

Network QoS, fairness and resource sharing control are not completely solved problems. Available solutions lack scalability due to maintaining flow state, require re-tuning if traffic changes, focus on a limited set of networking scenarios or require complex, centralized controllers and feedback loops. In this paper, we propose a core-stateless sol...

In our previous paper, we showed the M-tree index [7] using GiST in the PostgreSQL database. In this paper, we present that result and we extend that with some preliminary experimental results with other indexes. We compare the M-tree index with the BK-tree and the VP-tree indexes. These can be work in metric space with edit distance, that can be u...

In addition to classic ones, a new family of congestion controls regarded as "scalable" has recently emerged. Scalable congestion control exploits ECN to provide much finer control as rate scales, enabling reactions proportional to the congestion level. Nowadays, different initiatives propose the use of Scalable congestion control over the public I...

Several index structures are competing for efficient operations on various types of data, but there are some forms of information that cannot fit into the existing models, because by forcing them into one of the currently available representations they either lose some of their value or they do not have the necessary properties which would allow th...

Core-Stateless resource sharing control identifies flow aggregates in the edge and marks packets based on the relevant policies. Within the core of the network, no flow identification or policy knowledge is needed to realize the desired resource sharing. As packet marking needs trust and the behavior of core-routers is independent of the number of...

Extending fairness to multiple timescales creates the right incentives for users and provides better QoE for short sessions, e.g. for web page download. In this paper, we show how to define and implement multi-timescale fairness among flows independently of actual traffic mixes and resource capacities. The proposed method is built on the top of the...

Network QoS, fairness and resource sharing control are open challenges of network slicing and virtualization in 5G and future networks providing ultra-high speed Internet access. Traditional stateful solutions either employ the one-size-fits-all approach to provide services to end-users, regardless of the requirements of vertical services, or requi...

In this paper,we propose CSAQM, a novel approach of Active Queue Management (AQM) for network traffic with multiple Congestion Control algorithms. Our goal is similar to that of PI2 AQM that supports both Classic and Scalable TCP in a single queue. In contrast to existing solutions, CSAQM has two key advantages: 1) arbitrary congestion controls (in...

In this paper, we propose the PVPIE Active Queue Management (AQM) method that combines the packet scheduling and dropping algorithms of PIE AQM and the packet marking-based resource sharing of the Per Packet Value (PPV) concept. The algorithm calculates dropping probabilities needed for keeping the queueing delay at a predefined level using the PIE...

We have digital imprints generated by Smart City, banking systems, wearable sensors, IoT, mobile networks, social networks. The growing volumes of data generated by the information systems obtain values after proper analysis. Data algorithms and methods applicable for small volumes of data, do not work with several terabytes of data. There is a gro...

The usage of the semantic data is complicated for non-expert users, because the data are on many different SPARQL endpoints and the users need to know the URL of the endpoints. The federated systems are good solution for this problem. These systems interpret the SPARQL query and find the endpoints that can answer the query. Another advantage of the...

Cluster computing frameworks are important in the “Big Data” world. The famous common framework is the MapReduce that was introduced by Google. This framework is used by many of companies. However, this technique doesn't effectively solve all analytical problems. Some cases need another framework and these frameworks can work in the cluster. In thi...

An enormous amount of information stored in semantic format has become available nowadays. In order to browse this huge data, the development of different browsers has become necessary. Today, many browsers available, but these are typically desktop applications. Vast knowledge bases have been created by means of linking the different public datase...

Due to the spreading of semantic technologies, the volume of the datasets that are described in the Resource Description Framework (RDF) is dynamically growing. The RDF framework is suitable for integrating data from heterogeneous sources; however, the resulted datasets can be larger and extremely complex than before, new tools are needed to analyz...

When we write a SPARQL query, we need to know the structure of the dataset. In the relation databases the tables have a scheme, but the semantic data do not have. Autocompletion function exists in SQL environment, but it does not exist in SPARQL environment. We made a system that can help to write SPARQL query. The system has two features. The firs...

The LOD Cloud is a collection of the available datasets of the Semantic Web. The individual datasets typically store information about one specific area. These datasets can be queried using the SPARQL query language. Since the SPARQL 1.1 standard, it is possible to query several remote datasets with one query, and to combine the received data. This...

E-Science relies heavily on manipulating massive amounts of data for re-search purposes. Researchers should be able to contribute their own data and methods, thus making their results accessible and reproducible by others worldwide. They need an environment which they can use anytime and any-where to perform data-intensive computations. Virtual obs...

Widespread using of microblogs leads to have tremendous user generated data available which may characterize the social behavior and relationship of users. Beside the chance to extract some valuable information from the huge amount of data, there are a lot of non-trivial, task specific issue have to be solved to get real value. Detecting and charac...

E-Science relies heavily on manipulating massive amounts of data for research purposes. Researchers should be able to contribute their own data and methods, thus making their results accessible and reproducible by others worldwide. They need an environment which they can use anytime and anywhere to perform data-intensive computations. Virtual obser...

Nowadays, companies have to handle large amounts of data every day (e.g. employee data, reports, statements). These data are usually unstructured or semi-structured; they do not have a consistent format, since they come from various sources. As a solution, the Semantic Web provides a common data format, which helps integrate the heterogeneous data....

E-Science relies heavily on manipulating massive amounts of data for research purposes. Researchers should be able to contribute their own data and methods, thus making their results accessible and reproducible by others worldwide. They need an environment which they can use anytime and anywhere to perform data-intensive computations. Virtual obser...

In the paper we report on the parallel enumeration of the degree sequences (their number is denoted by G(n)) and zero-free degree sequences (their number is denoted by (G z (n)) of simple graphs on n=30 and n=31 vertices. Among others we obtained that the number of zero-free degree sequences of graphs on G z (30)=5876236938019300 and G z (31)=22974...

Cikkünkben a szemantikus adatok hatékony tárolásáról és lekérdezéséről mutatunk be néhány már megvalósított megoldást. A megoldások alapjai a Hadoop rendszer, ahol az adatok elosztva vannak tárolva (HDFS), és a lekérdezéseket elosztva értékeli ki a rendszer. A cikkben három fő problémát elemezgetünk. Az első az adatok hatékony tárolása az elosztott...

Indoor navigation is an important research topic nowadays. The complexity of larger buildings, supermarkets, museums, etc. makes it necessary to use applications which can facilitate the orientation. While for outdoor navigation already exist tried and tested solutions, but few reliable ones are available for indoor navigation. In this paper we inv...

Hadoop rendszeren történő kiértékelése a SPARQL SELECT lekérdezéseknek. A hadoop rendszer map és reduce folyamatokat használ kiértékelésre. A map rész megvizsgál bizonyos feltételeket, a reduce rész pedig ezek alapján számolja az eredményt. A rendszer elosztott környezetben képes futni.

Let a, b, m, and n be integers (0≤a≤b,1≤m≤n). An (a,b,n)-tournament [A. Iványi, Acta Univ. Sapientiae, Inform. 1, 71–88 (2009; Zbl 1178.68643)] is a directed loopless multigraph T=(V,A), where V={V 1 ,⋯,V n } and if 1≤i<j≤n, then V i and V j are connected with at least a and at most b arcs. The score sequence of T is the non-decreasing sequence of...

Indoor navigation is a very important research topic nowadays. Our goal was to investigate the possibilities of the indoor navigation systems. On the basis of our research we wanted design and implement an application on Android mobile. We used Augmented Reality (AR) and map for the visualization of the navigation. The novelty in our article contra...

Az Eötvös Loránd Tudományegyetem Informatikai Karának az Információs Rendszerek tanszékén a nyári szünetben elindult egy kutatási-fejlesztési projekt. A projekt alatt BSc-s hallgatók végezték a szakmai gyakorlatukat, mely során egyrészt az elméletben megtanult módszereket próbálhatták ki a gyakorlatban, másrészt kis csoportokban dolgozhattak együtt...