There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Wireless indoor positioning systems have become very popular in recent years. These systems have been successfully used in many applications such as asset tracking and inventory management. This paper provides an overview of the existing wireless indoor positioning solutions and attempts to classify different techniques and systems. Three typical location estimation schemes of triangulation, scene analysis, and proximity are analyzed. We also discuss location fingerprinting in detail since it is used in most current system or solutions. We then examine a set of properties by which location systems are evaluated, and apply this evaluation method to survey a number of existing systems. Comprehensive performance comparisons including accuracy, precision, complexity, scalability, robustness, and cost are presented.

Survey of Wireless Indoor Positioning Techniques and Systems

National Institute of Standards and Technology における超伝導研究及び生活

We present a new block cipher LED. While dedicated to compact hardware implementation, and offering the smallest silicon footprint among comparable block ciphers, the cipher has been designed to simultaneously tackle three additional goals. First, we explore the role of an ultra-light (in fact non-existent) key schedule. Second, we consider the resistance of ciphers, and LED in particular, to related-key attacks: we are able to derive simple yet interesting AES-like security proofs for LED regarding related- or single-key attacks. And third, while we provide a block cipher that is very compact in hardware, we aim to maintain a reasonable performance profile for software implementation.

The LED block cipher

In this paper we propose a new family of very efficient hardware oriented block ciphers. The family contains six block ciphers divided into two flavors. All block ciphers share the 80-bit key size and security level. The first flavor, KATAN, is composed of three block ciphers, with 32, 48, or 64-bit block size. The second flavor, KTANTAN, contains the other three ciphers with the same block sizes, and is more compact in hardware, as the key is burnt into the device (and cannot be changed).

The smallest cipher of the entire family, KTANTAN32, can be implemented in 462 GE while achieving encryption speed of 12.5 KBit/sec (at 100 KHz). KTANTAN48, which is the version we recommend for RFID tags uses 588 GE, whereas KATAN64, the largest and most flexible candidate of the family, uses 1054 GE and has a throughput of 25.1 Kbit/sec (at 100 KHz).

/pdf/katan-and-ktantan-a-family-of-small-and-efficient-hardware-1nbl4htw1x.pdf

KATAN and KTANTAN -- A Family of Small and Efficient Hardware-Oriented Block Ciphers

This paper describes a complete design flow for multiprocessor systems-on-chips (SoCs) covering the design phases from system-level modeling to FPGA prototyping. The design of complex heterogeneous systems is enabled by raising the abstraction level and providing several system-level design automation tools. The system is modeled in a UML design environment following a new UML profile that specifies the practices for orthogonal application and architecture modeling. The design flow tools are governed in a single framework that combines the subtools into a seamless flow and visualizes the design process. Novel features also include an automated architecture exploration based on the system models in UML, as well as the automatic back and forward annotation of information in the design flow. The architecture exploration is based on the global optimization of systems that are composed of subsystems, which are then locally optimized for their particular purposes. As a result, the design flow produces an optimized component allocation, task mapping, and scheduling for the described application. In addition, it implements the entire system for FPGA prototyping board. As a case study, the design flow is utilized in the integration of state-of-the-art technology approaches, including a wireless terminal architecture, a network-on-chip, and multiprocessing utilizing RTOS in a SoC. In this study, a central part of a WLAN terminal is modeled, verified, optimized, and prototyped with the presented framework.

UML-based multiprocessor SoC design framework

Finally a book on Wireless Sensor Networks that covers real world applications and contains practical advice! Kuorilehto et al. have written the first practical guide to wireless sensor networks. The authors draw on their experience in the development and field-testing of autonomous wireless sensor networks (WSNs) to offer a comprehensive reference on fundamentals, practical matters, limitations and solutions of this fast moving research area. Ultra Low Energy Wireless Sensor Networks in Practice: Explains the essential problems and issues in real wireless sensor networks, and analyzes the most promising solutions. Provides a comprehensive guide to applications, functionality, protocols, and algorithms for WSNs. Offers practical experiences from new applications and their field-testing, including several deployed networks. Includes simulations and physical measurements for energy consumption, bit rate, latency, memory, and lifetime. Covers embedded resource-limited operating systems, middleware and application software. Ultra Low Energy Wireless Sensor Networks in Practice will prove essential reading for Research Scientists, advanced students in Networking, Electrical Engineering and Computer Science as well as Product Managers and Design Engineers.

Ultra-Low Energy Wireless Sensor Networks in Practice: Theory, Realization and Deployment

Low energy consumption is a critical design requirement for most wireless sensor network (WSN) applications. Due to minimal transmission power levels, time-varying environmental factors and mobility of nodes, network neighborhood changes frequently. In these conditions, the most critical issue for energy is to minimize the transactions and time consumed for neighbor discovery operations. In this paper, we present an energy-efficient neighbor discovery protocol targeted at synchronized low duty-cycle medium access control (MAC) schemes such as IEEE 802.15.4 and S-MAC. The protocol effectively reduces the need for costly network scans by proactively distributing node schedule information in MAC protocol beacons and by using this information for establishing new communication links. Energy consumption is further reduced by optimizing the beacon transmission rate. The protocol is validated by performance analysis and experimental measurements with physical WSN prototypes. Experimental results show that the protocol can reduce node energy consumption up to 80% at 1-3m/s node mobility.

Energy-efficient neighbor discovery protocol for mobile wireless sensor networks

IEEE 1588 is a standard for precise clock synchronization for networked measurement and control systems in LAN environment. This paper presents the design and implementation of two IEEE 1588 prototypes for wireless LAN (WLAN). The first one is implemented using a Linux PC platform and a standard IEEE 802.11 WLAN with modifications to the network device driver. The second prototype is implemented using an embedded WLAN development board that implements the synchronization functionality using an embedded processor with programmable logic device (PLD) circuits. The measured results show that 1.1 ns average clock offset can be reached on HW based implementation, while Linux PC network driver enables 660 ns with a standard WLAN. Although WLAN is an extremely difficult environment for the synchronization, the results achieved with the prototype are fully comparable to those achieved with wired LAN implementations

Software and hardware prototypes of the IEEE 1588 precision time protocol on wireless LAN

This paper presents the design and implementation of a local positioning prototype The prototype implements received signal power level based positioning on IEEE 80211b wireless LAN (WLAN) platform In addition to a WLAN adapter, the prototype includes a host PC, which runs a positioning application The application computes and displays position estimates on the basis of measurements performed by the WLAN adapter A signal propagation model and an extended Kalman filter are used for enhancing the position estimates With the used WLAN hardware, the mean absolute error of positioning was measured to be 26 m

Marko Hännikäinen

Papers

UML-based multiprocessor SoC design framework

Ultra-Low Energy Wireless Sensor Networks in Practice: Theory, Realization and Deployment

Energy-efficient neighbor discovery protocol for mobile wireless sensor networks

Software and hardware prototypes of the IEEE 1588 precision time protocol on wireless LAN

Positioning with IEEE 802.11b wireless LAN