Maciej Nikodem

Error detection and error correction procedures for the advanced encryption standard

This paper presents a new algorithm for error detection and error correction in the data encrypted with the Advanced Encryption Standard (AES). The algorithm detects any byte error and over 99% of word errors affecting the data being encrypted. It is also capable of correcting all bit errors of odd multiplicity that are inducted into not more then four bytes of the data. Consequently the immunity of the AES to the fault analysis is improved.

Temperature-based covert channel in FPGA systems

This paper reports the temperature-based covert communication channel implemented in FPGA system. The channel enables bidirectional transmission and exchange of an arbitrary bit stream between two, electrically separated parts of the FPGA circuit during its normal operation. Transmission to and from the FPGA device is also reported. Transmitter and receiver modules are based on ring-oscillator which utilize 60 and 51 look-up tables respectively. The proof of concept was implemented in the Xilinx Spartan-IIE device and allows for transmission speed of 1/8 bit/s between FPGA and external transceiver. Internal communication is faster and allows to transmit up to 1 bit per second.

Upper Bounds on Network Lifetime for Clustered Wireless Sensor Networks

This paper focuses on the theoretical aspects of clustering in wireless sensor networks, as a mean to improve network lifetime. We investigate whether clustering itself (with no data aggregation) can improve network lifetime in particular application when compared to non-clustered networks. We use integer linear programming to analyse 1D and 2D networks, taking into account capabilities of real-life nodes. Our results show that clustering itself cannot improve network lifetime so additional techniques and means are required to be used in synergy with clustering.

Boolean logic function synthesis for generalised threshold gate circuits

This paper analyses negative differential resistance (NDR) based logic circuits operating in monostable-bistable transition logic element (MOBILE) regime. We formulate theoretical foundation for formal model of the generalised threshold gate (GTG) and prove that GTG can implement any, n-variable Boolean function. Moreover, we propose the algorithmic approach to GTG structure generation problem.

Low-cost and Universal Secure Scan: a Design- Architecture for Crypto Chips

Scan based design-for-test is a powerful testing scheme, but it can be used to retrieve secrets stored inside a crypto device. In this paper, we propose a novel scan based DFT architecture called secure scan that maintains the high test quality without compromising the security. Moreover our proposition is universal and can be easily implemented as an extension of the standard scan chain architecture. Apart from presenting our proposal we analyse its implementation complexity, tests efficiency impact and gained security level

Multi-hop and directed routing based on neighborhood cooperation in WSN

The paper describes a relational abstraction of neighborhood cooperation for Wireless Sensor Network (WSN) where node can identify its neighbors around it. Since radio links have limited range only some nodes have a direct contact with the Base Station (BS) and data transmission is executed using multi-hop communication to ensure that information is send from one node to another towards the BS. The novel abstract uses a subordination relation, to manage the neighbor cooperation between WSN nodes, that exploits topological properties of the WSN. Based on the hop-distance from the BS, any node k is able to establish a set N<(k) consisting of nodes to which k has to send communication messages in order to maintain the data-flow direction towards the BS.

Hierarchical control of a distributed solar collector field

This article presents a hierarchical control structure aimed at optimizing the electricity production process in solar power plants with distributed collectors. In these systems, a fluid is heated using the energy provided by the solar irradiation until a desired outlet temperature range is achieved, despite of the effect of disturbances (mainly radiation and inlet temperature),using as manipulated variable the fluid flow. The heated fluid is then used for feeding a heat exchanger where steam is produced for electricity generation using a turbine. Nonlinear models are used in the design of the different layers of the control architecture.

Relation-based Message Routing in Wireless Sensor Networks

Sensor networks and their related topics represent some of the greatest and challenging possibilities in the research field that have come about in recent years. Emerging technologies like wireless sensor network (WSN), standards enabled legacy sensors, ubiquitous and cloud computing, middleware, communication systems, internet protocols (IP) and next generation networks are leading to a set of new paradigms where wireless sensors can be treated as vital components of common infrastructure and a shared resource with an ability to serve multiple and concurrently executing applications run by various users in distributed environment. This is in strong contrast to traditional concepts where dedicated sensor devices are being physically and logically hard-wired to communication and computing infrastructure serving very specific and dedicated data/information processing applications. Wireless sensor networks consist of a number of small electronic devices (nodes) distributed in an area that by far exceeds the communication range of a single sensor. Message routing is one of the most important issues in such networks. This is mainly due to the large number of nodes, variety of possible communication paths, restricted power source and variability (in time and space) of environmental conditions in which the WSN operates. A shared communication channel and restricted communication ranges require that nodes of the WSN cooperate and/or coordinate their actions while messages are routed from nodes to the base station (BS). It is a well-known idea Descartes & Lafleur (1960) to solve large and complex problems by dividing them into smaller and possibly simpler tasks. The most crucial element of such an attempt is to decide how to divide the problem in order to get a problem that can be solved efficiently and, what is more important, can be used to find a solution to the original problem. A distributed system, such as a WSN, is traditionally seen as a set of spatially distributed nodes that communicate, coordinate their actions and inform other nodes about their status using special messages sent over the communication channel Dollimore et al. (2005). Such a system is usually assumed to be isolated from the outside word – even if it measures its parameters and/or listens to the status messages from other nodes, it is still not affected by the environmental conditions and its changes. We are going to look at such a system as it 7

Toolset for measuring thermal behavior of FPGA devices

In this work, we present a toolset suitable for the analysis of thermal behavior of FPGA devices. The toolset allows for the automatic synthesis of a unified temperature measurement and heat generation infrastructure combined with the necessary control structures and communication interfaces. The tools insert temperature sensors and heaters based on ring oscillators through the low level manipulations on Xilinx Design Language descriptions of FPGA resource allocations. The purpose of the kit is to support rapid setup of thermal experiments by providing basic heating and sensing elements with verified properties as well as an area-optimised IP core for control of the experiments.

Generalised threshold gate synthesis based on AND/OR/NOT representation of Boolean function

This paper focuses on generalized threshold gates (GTGs) that implement boolean logic functions using elements with negative differential resistance (NDR). GTGs are capable of implementing boolean functions, however, no effective synthesis algorithms have been proposed so far. We present that GTGs can be effectively implemented using unate functions. Our synthesis algorithm ensures that the circuit implementing n variable boolean function consists of at most n+2 NDR elements and can be further optimized by reducing the number of switching elements.