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).

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

Resource constrained platforms, dynamic nature, and complex applications set challenges to the development of wireless sensor networks (WSN). Sophisticated tasking and networking control is required in WSNs to reach lifetimes in order of years. This paper presents a WSN node middleware, which controls task allocation and WSN topology according to the current requirements of the application. The middleware uses a lightweight algorithm that balances communication and computation load between nodes. The discovering of resources and application tasks are comprised by a tuple space that selectively disperses information to nodes. The middleware has been implemented and evaluated in a wireless sensor network simulator (WISENES) that models resource usage and network operation accurately. The results show that in a static network configuration the obtained lifetime with our middleware is 6.8 times longer compared to an uncontrolled network while the increase in processing is negligible and the peek data memory usage increases by 11.6%. In a dynamically changing network the lifetime increases by a factor 3.9. Our middleware does not limit the applications and networks and improves the performance and predictability of WSNs significantly

A middleware for task allocation in wireless sensor networks

This paper proposes a new Enhanced Security Layer (ESL) for Bluetooth. The security level is increased by replacing the encryption with AES and adding in- tegrity protection. As ESL is placed on the top of the standard controller interface, it can be integrated into any Bluetooth implementation. A prototype implementation of ESL is presented. The security processing is implemented in hardware for high performance. The design consumes fewer resources and has higher throughput (214 Mb/s) than the standard design. The programming interface supports straightforward application development.

Design and implementation of an enhanced security layer for Bluetooth

The paper studies a configurable processor architecture, transport triggered architecture (TTA), for encryption algorithm implementations. The automatic TTA design space exploration is applied and configurations with good cost-performance ratio are found. It is shown that TTAs are at least equal to commercial processors in performance. According to earlier studies the performance level is also achieved at far lower cost. This encourages further development with tuned functionality.

Implementation of encryption algorithms on transport triggered architectures

The maintaining of the quality of service (QoS) of the data transfers in wireless local area networks (WLAN) is an extensive task. An implementation of an access point (AP) providing an access from WLANs to backbone wired networks is presented in this paper. The AP adapts the QoS signalling of the connected networks. The AP has been implemented in Windows NT workstation as a protocol driver and its operation has been verified. The evaluation of the driver performance encourages the usage of the AP in demanding environments.

Implementation of wireless LAN access point with quality of service support

A diagnostics systems module based on PC/104 computer platform standard has been developed A wireless diagnostics module is battery operated and connected to a diagnostics access point using IEEE 80211b wireless local area network (WLAN) link The diagnostics module performance is evaluated in the means of power consumption and wireless link capacity The results show that the power consumption of a PC/104 diagnostics module is high for battery operating systems However, it can be significantly reduced by component selection The IEEE 80211b wireless link performance is adequate for enabling diagnostics applications, but transfer delays can be significant with high network traffic load The PC/104 architecture is found to be suitable for industrial use The architecture can be easily implemented and changed for other types of applications

Marko Hännikäinen

Papers

A middleware for task allocation in wireless sensor networks

Design and implementation of an enhanced security layer for Bluetooth

Implementation of encryption algorithms on transport triggered architectures

Implementation of wireless LAN access point with quality of service support

PC/104 based wireless diagnostics module