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 presents a new method for run-time management of shared processing resources in multiprocessor systems on chip. A centralized resource manager unit performs dynamic allocation of shared processing resources according to the system state and given constraints. It implements a hardware mutual exclusion so that no inter-processor synchronization is required for accessing the resources. Moreover, it supports dynamic power management. In addition, a hardware implementation of the resource manager is proposed. In a case study, a resource manager is evaluated in a data-parallel MPEG-4 video encoder on multiprocessor system on chip on FPGA. The RM eases the design of six different architectures featuring two to twelve shared hardware accelerators. Only a few accelerators are required for the best performance as the accesses are efficiently scheduled.

Flexible management of shared resources on multiprocessor system on chip

Wireless Sensor Networks (WSNs) consist of densely deployed, independent, and collaborating low cost sensor nodes. The nodes are highly resource-constrained in terms of energy, processing, and data storage capacity. Thus, the protocols used in WSNs must be highly energy-efficient. WSN communication protocols achieving the lowest power consumption minimize radio usage by accurately synchronizing transmissions and receptions with their neighbors. In this paper, we show how network signaling frames of state-of-the-art synchronized communication protocols for low-power WSNs supporting mobile nodes can be used for positioning. We derive mathematical models for node power consumption analysis. The models provide a tool for estimating what kind of network lifetimes can be expected when average positioned node speed, the amount of anchor nodes required by the location estimation algorithm, and the location refresh rate required by the application are known. The presented analysis results are based on two kinds of node hardware: real node hardware prototypes having no Received Signal Strength Indicator (RSSI) support and typical values of an integrated chip using an IEEE 802.15.4 compliant radio with RSSI.

Positioning in resource-constrained ultra low-power Wireless Sensor Networks

This paper presents an add-on Class of Service (CoS) layer for wireless mesh networks. The proposed protocol is applicable for contention-based MACs and is therefore compatible with most of the Wireless Local Area Network (WLAN) and Wireless Sensor Network (WSN) protocols. The protocol has a locally centralized control for managing data flows, which either reserve a fixed bandwidth or are weighted by fair scheduling. The protocol reduces transmission collisions, thus improving the overall throughput. IEEE 802.11 adhoc WLAN has been taken as a platform for simulations and prototyping for evaluating the protocol performance. Network Simulator Version 2 (NS2) simulations show that the CoS protocol efficiently differentiates bandwidth, supports bandwidth reservations, and reaches less than 10 ms transfer delay on IEEE 802.11b WLAN. Testing with a full prototype implementation verified the performance of the protocol.

/pdf/class-of-service-support-layer-for-wireless-mesh-networks-3t48rehoea.pdf

Class of Service Support Layer for Wireless Mesh Networks

A vast number of sensors exists in the sensor industry that can be used to measure physical parameters, such as temperature, pressure, humidity, illumination, gas, flow rate, strain, and acidity. Standardized sensor interfaces, data formats, and communication protocols are required to enable effective integration, access, fusion, and the use of sensor-derived data. The goal is to allow sensors from different manufacturers to work together without human intervention and customization.

Key Standards and Industry Specifications

The software components in WSNs include sensor operating systems and middleware as shown in Fig. 5.1. The purpose of these is to ease the application development by providing network access and allowing support for heterogeneous platforms with hardware abstraction.

Marko Hännikäinen

Papers

Flexible management of shared resources on multiprocessor system on chip

Positioning in resource-constrained ultra low-power Wireless Sensor Networks

Class of Service Support Layer for Wireless Mesh Networks

Key Standards and Industry Specifications

Software and Middleware Services