485 research outputs found

    Investigation of Techniques for Reducing Mobile Communication Systems Harmful Out-Of-Band Emission

    Get PDF
    Electromagnetic compatibility in the newly designated Long-Term Evolution (LTE) mobile network in the 790–862 MHz frequency band from perspective of interference management between neighbouring services are analysed in the dissertation. Main focal point of this dissertation is on the problems that face LTE networks based on Orthogonal Frequency-Division Multiplexing (OFDM) due to the relatively strong side lobes around the active subcarriers in the main communication channel, which introduces interference effects between LTE stations and other services. The introductory chapter presents the investigated problem, objects of research, importance of the dissertation, describes research methodology, scientific novelty and the defended statements. The situation in the 790–862 MHz frequency band is overviewed regarding most sensitive challenges in the first chapter: LTE stations’ influence on Short-Range Devices (SRD), digital terrestrial TV broadcasting (DVB-T) and aeronautical radio navigation systems (ARNS). The noticeable lack of information is observed regarding SRD and LTE electromagnetic compatibility. The Filter Bank Multicarrier Transmission technique (FBMC) is pro-posed as means to minimize adjacent band interference in the 790–862 MHz frequency band. Main FBMC benefits are presented through comparison with reference case of OFDM. The key advantage of FBMC technique is derived from its low out-of-band leakage, which guarantees minimum harmful interference level between stations using adjacent channels. The harmful interference of LTE mobile stations’ influence on Short-Range Devices operating in the 863–870 MHz frequency band is analysed in the second chapter. Two analysis methods are used in this study: first applying theoretical analysis using Minimum Coupling Loss calculations, then statistical Monte-Carlo in order to verify results obtained in theoretical approach. The third chapter is focused on the experimental analysis to reproduce the situation that was investigated in theoretical analysis chapter. Verification of theoretical analysis by practical measurements confirmed that the LTE user equipment (UE) emissions may affect SRD devices and completely or partially disrupt their communications at distances of up to several meters from LTE UE. The obtained results are summarized and general conclusions are drawn

    Research on rules-based business process modelling and simulation

    Get PDF
    Googling the term “Business Process Simulation” in April 2013 yielded only 42.1 thousand hits. It is not much compared with googling the term such as “Business Process Modelling” in the same time, which yielded approx. 1.470 million hits. That is 35 times more compared to the previous search. The difference between modelling and simulation is arguable. In fact, the terms ‘simulation’ and ‘modelling’ are often used synonymously, but the authors prefer to distinguish between the terms and look at modelling as an act of building a model while simulation is considered an act or even a process of using that model for a specific purpose or study. If simulation is a manipulation process of one or more variables, which can be changed and observed, then this kind of process is best managed and controlled by business rules that can also be manipulated in the simulation process. Article in English. Taisyklėmis grindžiamų verslo procesų modeliavimo ir simuliavimo tyrimas Santrauka „Google“ paieškoje įvestas terminas „Business Process Simulation“ 2013 metų balandžio mėn. duoda tik 42,1 tūkst. paieškos rezultatų. Tai nėra daug, palyginti su kitu paieškos terminu „Business Process Modelling“. Tuo pačiu metu reikšminiai paieškos žodžiai duoda apie 1,470 milijono paieškos rezultatų. Tai 35 kartus daugiau, palyginti su prieš tai daryta paieška. Galima ginčytis, ar yra skirtumas tarp modeliavimo ir simuliavimo? Iš tiesų žodžiai „modeliavimas“ ir „simuliavimas“ dažnai vartojami kaip sinonimai, tačiau straipsnyje siūloma į modeliavimą ir simuliavimą žiūrėti skirtingai, t. y. į modeliavimą kaip į veiksmą, kuris sukuria modelį, į simuliavimą – kaip į veiksmą arba procesą, kuris sudaro sąlygas taikyti šį modelį konkrečiam tikslui arba tyrimui atlikti. Jeigu apibrėžiama, kad simuliavimas yra vieno ar daugiau kintamųjų manipuliacijos procesas, kurį galima pakeisti ir stebėti, tada taip pat galima susitarti, kad šis procesas geriausiai grindžiamas verslo taisyklėmis, kurios gali būti papildomos arba keičiamos simuliavimo proceso metu. Reikšminiai žodžiai: verslo procesų modeliavimas, verslo procesų simuliavimas, verslo taisyklės

    Towards Sustainable Cryptocurrency: Risk Mitigations from a Perspective of National Security

    Get PDF
    Cryptocurrency market is developing fast during the past few years. Cryptocurrency now is available as a form of payment for retail goods, as an instrument for a wholesale international transaction a mean of exchange for whatever goods and is available through ATM’s. Moreover, it is developing as a possibility for fundraising a) as a private debt b) as seed capital. Companies like Facebook are discussing launching own cryptocurrency. Bank UBS is developing its blockchain based virtual currency as well. However, scientist agrees that cryptocurrency has an important impact to national security. It became a relevant instrument for illegal good transactions, a mean of exchange in the darknet and an instrument for money laundering or infrastructure for new kind of money-laundering practices (for example- “Smurfing” phenomena (EU Observer, 2019)) European Union is launching AML and KYC procedures for the cryptocurrency market. Would it be efficient? Why are we implementing KYC and AML procedures for cryptocurrency? Is it able to minimize risks

    Cryptocurrency as Disruptive Technology: Theoretical Insighs

    Get PDF
    Bitcoin, Cryptocurrencies and Blockchain technologies are widely discussed nowadays. The Bitcoin market value is discussed in top magazines, the names of people who earned money from cryptocurrencies are on the Richest People list. The Blockchain technology is said to be a one of disruption pioneers on the one hand, and cryptocurrency is said to be an illegal phenomenon on the other hand. The Fourth Industrial Revolution, which is based on digitalized industry is changing the power centres. Will cryptocurrency disrupt the financial sector? Or perhaps it will disrupt the retail market or global monetary policy. Disruptive technologies together with the Internet, Mobile Internet and Internet of Things are changing our world. While society has gained simple and reachable comfort for a cheaper price on the one hand, many people have lost their jobs on the other. Consequently, the authors presuppose discussion about the phenomenon of cryptocurrency through the context of social phenomena and legal regulation: divulge definitions, principles, relating to the topic; identify possible tendencies according to legal regulation and its practical realization

    Rizikos samprata ir jos valdymas muitinėje.

    Get PDF
    The theme that is concerned was not studied in Lithuania. The definition "Risk" is very common in our days and can be detected in any ground. This term is known from Antic period and evolved until our days. If it has meaning of dangerous rock in the beginning, now it is used in different meanings, for example in civil, criminal, labour law, in economy, insurance sphere, even in public administration area. Customs authority is governmental instrument, which have rights not only control foreign trade, flow of goods from other countries, but also rights for intelligence and violation investigation activity. More and more customs move from traditional duties to new tasks – fight with terrorism, combating crimes related to the trafficking of drugs, mass destruction weapons, safety of goods and society and etc. This is a reason why customs is a pioneer in Lithuania when we speak about new methodology in public administration and relation with trade and business. It is agreed that customs has more experience and in risk management area. Because risk management is each customs authority business, there exist a lot of understandings of it, like process itself and management of it, if we look to different countries we will find different interpretation. Only in few last years there were few tries to make unique understanding of this process and put all elements of it in one document. Such examples can be Risk management guide from World Customs Organisation and Mapping document of risk management from European Union Council.Muitinėje sprendžiamos pasaulinės prekybos ir prekių judėjimo problemos, numatoma nusikalstamumo, įskaitant organizuotą, būklė, gerinamas prekių ir keleivių judėjimas per valstybines sienas. Straipsnyje grindžiama nuomonė, kad spręsdama šiuos klausimus, muitinė privalo remtis moderniausiais kontrolės metodais bei veiksmingai naudoti turimus išteklius. Pastarąjį dešimtmetį susidomėta rizikos valdymu ir jos naudojimu viešajame sektoriuje, tačiau moksliniu požiūriu rizikos problematika iki šiol nepakankamai gerai ištirta. Siekiant sėkmingai valdyti arba kontroliuoti reiškinius, būtina nustatyti rizikos laipsnį ir dydį, išreiškiant rizikos kategorijas, paskirstant išteklius ir juos nukreipiant į riziką. Straipsnyje apibrėžiamas terminas „rizika“, kitos reikšmingos šios srities sąvokos, nagrinėjamas rizikos analizės tikslas, jos turinys ir valdymo proceso elementai muitinėje, pagrindžiama, kad rizikos valdymas yra vienas iš šiuolaikinių darbo metodų, reikšmingų ne tik muitinėms, bet ir kitoms valstybinėms institucijoms, turinčioms valdymo įgaliojimus

    Simulation of electromagnetic field propagation generated by radio waves from antennas for mobile cellular communications

    Get PDF
    The methods frequently employed for predicting the intensity of an electromagnetic field in urban localities are based on empirically established factors. In order to predict the intensity of the electromagnetic field in an adjacent transmitter zone and on building facade flats, the method of simulating of direct visibility rays seems to be a suitable tool. With reference to the introduced method, the article describes the offered algorithm applied for performing experimental calculations. Also, the method of monitoring has been based on the calculated values of the intensity of the electromagnetic field

    Selecting the distinctive points of the land surface for modelling the relief

    Get PDF
    In order to prepare a project on rebuilding an old or constructing a new road and work drawings, knowledge of the present local objects is necessary. The performance of road construction or reconstruction is aimed at using digital models for the relief and at helping with more precise design, a decrease in the environmental impact and work optimization. Digital local models are most frequently prepared according to data on laser scanning. Redundant metering data on height points have been accumulated using a laser scanning technique. Because of redundant height points, for automatically creating and designing a model for the relief, computer resources must be irrationally used under slower modelling processes. The methodology provided in the article could be suitable for eliminating redundant points of height metering keeping them in distinctive relief positions. According to the proposed methodology, an algorithm has been created and used in the experimental theory for eliminating redundant points. In order to check the correctness of algorithm performance, a project on road reconstruction has been simulated and the volumes of land works using relief models created in the event of the full and filtrated array of height points have been compared
    corecore