A Test Bed for Evaluating the Performance of IoT Networks

The use of smaller, personal IoT networks has increased over the past several years. These devices demand a lot of resources but only have limited access. To establish and sustain a flexible network connection, 6LoWPAN with RPL protocol is commonly used. While RPL provides a low-cost solution for connection, it lacks load balancing mechanisms. Improvements in OF load balancing can be implemented to strengthen network stability. This paper proposes a test bed configuration to show the toll of frequent parent switching on 6LoWPAN. Contiki’s RPL 6LoWPAN software runs on STM32 Nucleo microcontrollers with expansion boards for this test bed. The configuration tests frequency of parent changes and packet loss to demonstrate network instability of different RPL OFs. Tests on MRHOF for RPL were executed to confirm the working configuration. Results, with troubleshooting and improvements, show a working bed. The laid-out configuration provides a means for testing network stability in IoT networks

FibLSS: A scalable label storage scheme for dynamic XML updates

Dynamic labeling schemes for XML updates have been the focus of significant research activity in recent years. However the label storage schemes underpinning the dynamic labeling schemes have not received as much attention. Label storage schemes specify how labels are physically encoded and stored on disk. The size of the labels and their logical representation directly influence the computational costs of processing the labels and can limit the functionality provided by the dynamic labeling scheme to an XML update service. This has significant practical implications when merging XML repositories such as clinical studies. In this paper, we provide an overview of the existing label storage schemes. We present a novel label storage scheme based on the Fibonacci sequence that can completely avoid relabeling existing nodes under dynamic insertions. Theoretical analysis and experimental results confirm the scalability and performance of the Fibonacci label storage scheme in comparison to existing approaches

Near-capacity joint source and channel coding of symbol values from an infinite source set using Elias Gamma Error correction codes

In this paper we propose a novel low-complexity Joint Source and Channel Code (JSCC), which we refer to as the Elias Gamma Error Correction (EGEC) code. Like the recently-proposed Unary Error Correction (UEC) code, this facilitates the practical near-capacity transmission of symbol values that are randomly selected from a set having an infinite cardinality, such as the set of all positive integers. However, in contrast to the UEC code, our EGEC code is a universal code, facilitating the transmission of symbol values that are randomly selected using any monotonic probability distribution. When the source symbols obey a particular zeta probability distribution, our EGEC scheme is shown to offer a 3.4 dB gain over a UEC benchmarker, when Quaternary Phase Shift Keying (QPSK) modulation is employed for transmission over an uncorrelated narrowband Rayleigh fading channel. In the case of another zeta probability distribution, our EGEC scheme offers a 1.9 dB gain over a Separate Source and Channel Coding (SSCC) benchmarker

Fast and simple high-capacity quantum cryptography with error detection

Quantum cryptography is commonly used to generate fresh secure keys with quantum signal transmission for instant use between two parties. However, research shows that the relatively low key generation rate hinders its practical use where a symmetric cryptography component consumes the shared key. That is, the security of the symmetric cryptography demands frequent rate of key updates, which leads to a higher consumption of the internal one-time-pad communication bandwidth, since it requires the length of the key to be as long as that of the secret. In order to alleviate these issues, we develop a matrix algorithm for fast and simple high-capacity quantum cryptography. Our scheme can achieve secure private communication with fresh keys generated from Fibonacci- and Lucas- valued orbital angular momentum (OAM) states for the seed to construct recursive Fibonacci and Lucas matrices. Moreover, the proposed matrix algorithm for quantum cryptography can ultimately be simplified to matrix multiplication, which is implemented and optimized in modern computers. Most importantly, considerably information capacity can be improved effectively and efficiently by the recursive property of Fibonacci and Lucas matrices, thereby avoiding the restriction of physical conditions, such as the communication bandwidth

Kompresia biologických sekvencií

Objem dát získavaných sekvenovacími technológiami novej generácie rastie podstatne rýchlejšie ako kapacity úložných médií. Výstupy sekvenátorov okrem samotných prečítaných krátkych úsekov DNA obsahujú ďalšie informácie napr. o spoľahlivosti/kvalite čítania každého symbolu DNA. Takéto dáta je treba ďalej uchovávať aj po zostavení sekvencie kompletného genómu. Štandardným formátom pre ukladanie dát v tejto oblasti je formát SAM (Sequence Alignment/Mapping Format) a jeho binárna komprimovaná verzia BAM, ktorá umožňuje náhodný prístup k svojmu obsahu. V tejto práci popíšeme konštrukciu lepšej kompresnej schémy pre bezstratovú kompresiu súborov vo formáte SAM/BAM. Táto kompresná schéma dosahuje podstatne menšiu veľkosť komprimovaného súboru ako pri formáte BAM. Navyše však zostáva zachovaná možnosť náhodného prístupu k dátam v komprimovanom súbore. Implementácia tejto kompresnej schémy je platformovo nezávislá a umožňuje jednoduchú konfiguráciu použitých kompresných metód. Navrhovali sme ju tak, aby bola v budúcnosti možná jej jednoduchá rozšíriteľnosť - vďaka tomu bude možné reagovať na zmeny v sekvenovacích platformách, ako aj na zmeny vo formáte SAM.Volumes of data obtained from the next generation sequencing platforms is growing faster than the available capacity of storage media. Sequencers mainly produce short reads of DNA. However, output of the sequencing machines also contains other information, for example information about read reliability/quality. This data must be archived even after successful complete genome assembly. Standard file format used for this type of data is format SAM (Sequence Alignment/Mapping Format) and its binary compressed version BAM. In this thesis we describe the construction of a better lossless compression scheme for compression of files in the SAM/BAM format. This compression scheme provides better compression ratios than the BAM format. In addition, random access to data in the compressed file is retained. Implementation of this compression scheme is platform independent and allows simple configuration of the compression process. Implementation also offers easy extensibility. Thanks to this, we will be able to respond to changes in current sequencing platforms as well as to changes in the SAM format.Department of Software and Computer Science EducationKatedra softwaru a výuky informatikyFaculty of Mathematics and PhysicsMatematicko-fyzikální fakult

Robust Universal Complete Codes for Transmission and Compression

Several measures are defined and investigated, which allow the comparison of codes as to their robustness against errors. Then new universal and complete sequences of variable-length codewords are proposed, based on representing the integers in a binary Fibonacci numeration system. Each sequence is constant and need not be generated for every probability distribution. These codes can be used as alternatives to Huffman codes when the optimal compression of the latter is not required, and simplicity, faster processing and robustness are preferred. The codes are compared on several "real-life" examples. 1. Motivation and Introduction Let A = fA 1 ; A 2 ; \Delta \Delta \Delta ; An g be a finite set of elements, called cleartext elements, to be encoded by a static uniquely decipherable (UD) code. For notational ease, we use the term `code' as abbreviation for `set of codewords'; the corresponding encoding and decoding algorithms are always either given or clear from the context. A code i..