Cryptographic accumulators are a tool for compact set representation and secure set membership proofs. When an element is added to a set by means of an accumulator, a membership witness is generated. This witness can later be used to prove the membership of the element. Typically, the membership witness has to be synchronized with the accumulator value, and to be updated every time another element is added to the accumulator. In this work we propose an accumulator that, unlike any prior scheme, does not require strict synchronization. In our construction a membership witness needs to be updated only a logarithmic number of times in the number of subsequent element additions. Thus, an out-of-date witness can be easily made current. Vice versa, a verifier with an out-of-date accumulator value can still verify a current membership witness. These properties make our accumulator construction uniquely suited for use in distributed applications, such as blockchain-based public key infrastructures.

Phytoremediation is an innovative technology employing plants for reclamation of soils that have been polluted by industrial contaminants. While it is frequently slower than traditional physicochemical remediation techniques, there are, however, many significant advantages including simplicity, low cost, improvement of soil structure and microbiological fertility. While various hyperaccumulators have been reported from Europe and the USA, there is a need to identify Australian species. This study reports a number of metal accumulators following a soil and vegetation survey of two metal contaminated sites in New South Wales, the spoil (filtercake) heaps of the BHP (Broken Hill Propriety ) steelworks at Port Kembla and the abandoned mine at Sunny Corner. BHP is the largest manufacturer of steel in Australia. The Port Kembla is the largest single steel manufacturing site. Solid by-products from this site totalled 3.1 million tons in 1988. The Sunny Corner mine site was mainly a silver mine which operated over approximately 100 hectares 1184 to 1922 and produced over 100 tonnes of silver during that period. The soil and water in and around the site is heavily contaminated with metals and is distinctly acidic. It was concluded that Ricinus communis, Sonchus oleraceus, baeckea utilis, Poa labillardieri and Pinus radiata are options for heavy metal phytoremediation of contaminated Australian soils. Arbuscular Mycorrhizal infection (particular with Glomus and Gigaspora strains) should be promoted for optimum growth. / Doctor of Philosophy (PhD)

This master thesis is focused on the comparison of electric drive and drive with an internal combustion engine. The literary overview shows the history and beginnings of the first attempts to create a vehicle with an electric energy. This all goes back to the half of 19th century. In this thesis are also included types of electric engines which are used in drives. Great attention is focused on the several types of accumulators and their charging. The last chapter in the theoretical part is dedicated to the ecological aspect of commission and the production of electric energy which is used to the drive of the electric car. The second, practical, part deals with two levels. Concretely with the technical part where are compared the on-road performance, comfort, noise and functionality of the BMW i3 and Renault Clio. Another economical part which is focused mainly on the operating costs and the affordability of vehicles which were tested.

The master's thesis is devoted to the comparison of different types of lithium-ion batteries. Primarily, an introduction to electrochemical power sources and their division is described. Furthermore, the thesis deals only with lithium-ion batteries. In the theoretical part, the chapters discuss the history, the principle of operation and a detailed description of the main battery parts, including used materials. A comparison of commercially available lithium-ion cells with each other as well as with other types of batteries is also included in the theoretical part. The practical part deals with the cyclinf of lithium-ion cells and subsequent evaluation of the effect of temperature on the capacitance and current characteristics of these lithium-ion batteries.

Diploma thesis is involved in basic properties of nickel materials for alkaline accumulators. Practical part deals with measuring of nickel hydroxides by cyclic voltametry. Next practical part is above measuring and optimalization various proportion of nickel and cobalt in layer made by electrodeposition on nickel electrodes.

The goal of this thesis is describe properties accumulators used in medical industry and proposal automatic baterry charger for medical equipment. The first part of the master’s thesis describes the most commonly used types of electrochemical accumulator systems used in the medical industry. Further listed are the criteria for the identification of the accumulator charge status. The second part of the master’s thesis defines demands on automatic baterry charger and proposal factual network solution.

This master´s thesis deals with stability of electrolytes and electrodes using electrochemical methods of Li-ion batteries. The first part of the project is devoted to the characteristics of Li-ion batteries, electrochemical reactions and characteristics of electrode materials. Consenquetial part is concentrated on preparation and measurement of elektrolyte EC : DMC with 1M LiPF6. The elektrolyte was investigated using galvanostatic method, cyclic voltammetry and impedance spectroscopy.

The concept of the Internet of Things is driven by advancements of the Internet with the interconnection of heterogeneous smart objects using different networking and communication technologies. With the rapidly increasing number of interconnected devices present in the life of a person, providing authentication and secure communication between them is considered a key challenge. The integration of Wireless Sensor Networks in the Internet of Things creates new obstacles due to the necessity of finding a balance between the resources utilization and the applied security solutions. In multicast group communications, the energy consumption, bandwidth and processing overhead at the nodes are minimized in comparison to a point-to-point communication system. To securely transmit a message in order to maintain confidentiality of the data and the user’s privacy, usually involves human interaction or the pre-agreement upon some key, the latter unknown to an external attacker. In this thesis, the author proposed an authentication protocol based on the similar context between the correct devices and lightweight computationally secure group-key establishment, avoiding any kind of human involvement. The goal is achieved by having the devices calculate a fingerprint from their ambient context and through a fuzzy commitment scheme generating a commitment respectively opening value which is used to generate a common secret key between them. The tests are effected on real world data accumulated from different environments. The proposed scheme is based on elliptic curve cryptography and cryptographic one-way accumulators. Its feasibility is analyzed by implementing the group key establishment phase in the Contiki operating system and by simulating it with the Cooja simulator. Furthermore, the applicability of the protocol is analyzed and justified by an analysis of the storage overhead, communication overhead, and energy consumption. The simulator shows an energy consumption of only 112 mJ per node for group key establishment. The results obtained in this thesis demonstrate the feasibility of the scheme, it’s computational, and communication costs are further comparable to other similar approaches.

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Baigiamajame darbe tiriama pramonės įmonių tarša pasyviosios lichenoindikacijos, pasyvaus kaupimo ir biotestavimo metodais. Darbo objektas - tyrimo metu vertintos įmonių teritorijose ant medžių aptinkamos epifitinių kerpių rūšys, taip pat vertinama teršalų sklaida pagal sėjamosios pipirnės (Lepidium sativum L.) augimą ant kiminų (sugėrusių įmonių išmetamus oro teršalus) terpės. Darbo tikslas – įvertinti oro kokybę pramonės įmonių teritorijose pagal ten aptinkamas epifitinių kerpių rūšis ir sėjamosios pipirnės (Lepidium sativum L.) augimą bei gautus rezultatus palyginti su pasyviųjų kaupiklių rezultatais. Darbo metodai – tyrimai buvo atliekami 2013-2014 metais didžiausias teršalų koncentracijas Šakių rajone išleidžiančių įmonių: UAB „Idavang“ ir UAB „Kriūkų baldai“ teritorijose. Tyrimo vietose 100 m, 200 m ir 500 m atstumais nuo taršos šaltinių buvo vertinamos ant medžių aptiktos epifitinių kerpių rūšys, kiekvienos rūšies padengimas procentais ir poleotolerantiškumo indeksas, taip pat vertintas biotestinio organizmo sėjamosios pipirnės (Lepidium sativum L.) augimas kiminų (augusių taršos šaltinių zonose) terpėje bei azoto dioksido koncentracijos iš pasyviųjų kaupiklių. Darbo rezultatai. Tyrimo objektų teritorija pasižymi nedidele kerpių gausa. Iš viso identifikuota 17 skirtingų kerpių rūšių abiejų tyrimo objektų teritorijose: 5 krūmiškosios, 8 lapiškosios ir 4 žiauberiškosios. Tiek UAB „Idavang“, tiek UAB „Kriūkų baldai“ teritorijose tolstant nuo taršos šaltinio... [toliau žr. visą tekstą] / In this thesis industrial company's pollution is investigated using passive Lichen Indication method, passive accumulation and biotesting methods. Object of research: Two species of plants were selected: garden cress (Lepidium sativum L.) and epiphytic lichen. During the evaluation we examined epiphytic lichen found on trees surrounding the territories of industrial companies and evaluated pollution dispersion by the growth of garden crass (Lepidium sativum L.) on sphagnum (which have absorbed the air pollutants produced by the companies) seedbed. Aim of the research: The aim of this research is to evaluate the air quality in the territories of industrial companies by the types of epiphytic lichen found in the perimeter and the spread of garden cress (Lepidium sativum L.) on sphagnum (which have absorbed the air pollutants produced by the companies) seedbed. Methods. The evaluation took place in year 2013-2014 in the territories of the most polluting companies in Šakiai district: UAB “Indavang” and UAB “Kriūkių baldai”. At distances of 100, 200 and 500 meters from the pollution source different types of epiphytic lichen were examined, as well as their coverage in percents and polio tolerance index. Both biotest organism's garden crass (Lepidium sativum L.) growth in sphagnum seedbed (growing in the pollution source territory) and nitrogen dioxide concentration from passive accumulators were evaluated. Results. Territories evaluated in this research have a small... [to full text]