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

Machine Learning is the study of methods for programming computers to learn. Computers are applied to a wide range of tasks, and for most of these it is relatively easy for programmers to design and implement the necessary software. However, there are many tasks for which this is difficult or impossible. These can be divided into four general categories. First, there are problems for which there exist no human experts. For example, in modern automated manufacturing facilities, there is a need to predict machine failures before they occur by analyzing sensor readings. Because the machines are new, there are no human experts who can be interviewed by a programmer to provide the knowledge necessary to build a computer system. A machine learning system can study recorded data and subsequent machine failures and learn prediction rules. Second, there are problems where human experts exist, but where they are unable to explain their expertise. This is the case in many perceptual tasks, such as speech recognition, hand-writing recognition, and natural language understanding. Virtually all humans exhibit expert-level abilities on these tasks, but none of them can describe the detailed steps that they follow as they perform them. Fortunately, humans can provide machines with examples of the inputs and correct outputs for these tasks, so machine learning algorithms can learn to map the inputs to the outputs. Third, there are problems where phenomena are changing rapidly. In finance, for example, people would like to predict the future behavior of the stock market, of consumer purchases, or of exchange rates. These behaviors change frequently, so that even if a programmer could construct a good predictive computer program, it would need to be rewritten frequently. A learning program can relieve the programmer of this burden by constantly modifying and tuning a set of learned prediction rules. Fourth, there are applications that need to be customized for each computer user separately. Consider, for example, a program to filter unwanted electronic mail messages. Different users will need different filters. It is unreasonable to expect each user to program his or her own rules, and it is infeasible to provide every user with a software engineer to keep the rules up-to-date. A machine learning system can learn which mail messages the user rejects and maintain the filtering rules automatically. Machine learning addresses many of the same research questions as the fields of statistics, data mining, and psychology, but with differences of emphasis. Statistics focuses on understanding the phenomena that have generated the data, often with the goal of testing different hypotheses about those phenomena. Data mining seeks to find patterns in the data that are understandable by people. Psychological studies of human learning aspire to understand the mechanisms underlying the various learning behaviors exhibited by people (concept learning, skill acquisition, strategy change, etc.).

Machine learning

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

The PASCAL Visual Object Classes Challenge

An overview of the self-organizing map algorithm, on which the papers in this issue are based, is presented in this article.

The Self-Organizing Map

An RF-based indoor localization design targeted for wireless sensor networks (WSNs) is presented. The energy-efficiency of mobile location nodes is maximized by a localization medium access control (LocMAC) protocol. For location estimation, a location resolver algorithm is introduced. It enables localization with very scarce energy and processing resources, and the utilization of simple and low-cost radio transceiver HardWare (HW) without received signal strength indicator (RSSI) support. For achieving high energy-efficiency and minimizing resource usage, LocMAC is tightly cross-layer designed with the location resolver algorithm. The presented solution is fully calibration-free and can cope with coarse grained and unreliable ranging measurements. We analyze LocMAC power consumption and show that it outperforms current state-of-the-art WSN medium access control (MAC) protocols in location node energy-efficiency. The feasibility of the proposed localization scheme is validated by experimental measurements using real resource constrained WSN node prototypes. The prototype network reaches accuracies ranging from 1 m to 7 m.With one anchor node per a typical office room, the current room of the localized node is determined with 89.7% precision.

https://link.springer.com/content/pdf/10.1155%2F2008%2F731835.pdf

A Wireless Sensor Network for RF-Based Indoor Localization

Mobile IPv6 provides comprehensive mobility management for the IPv6 protocol. It provides many benefits compared to Mobile IPv4, such as reroute optimization, protocol extensions and IP Security (IPSec). One problem still remains; the handover time is relatively long. This is a big problem at least in real-time connections. This paper presents a new method for faster handover in IPv6 networks, called Flow based Fast Handover for MIPv6 (FFHMIPv6), which uses the features of the IPv6 protocol and benefits from IPv6 traffic control.

Flow-based Fast Handover method for Mobile IPv6 network

Condition monitoring in buildings is one of the most potential and foreseen applications for wireless sensor networks (WSN). This paper presents the design and full scale prototype implementation of WSN for temperature monitoring. The prototypes are implemented using low power commercial of-the-shelf components including a 2.4 GHz radio, microcontrollers, and a custom TUTWSN communication protocol. A user application provides a graphical data analysis. Measurements indicate 183 muW to 390 muW average node power consumptions, as temperature is measured at 5 s intervals and data is multi-hop routed to a gateway. Predicted lifetime with two AA batteries is up to 4.9 years. In addition, experiments indicate that time accuracy is extremely important in hardware prototypes

Ultra low energy wireless temperature sensor network implementation

Methods and arrangements are provided for handling, within a communications system comprising a distributed domain (301) and a central domain (303), electronic records that contain predictions of the outcome of a certain incident. Within the distributed domain (301) there is generated (304), before the outcome of the incident is known, a multitude of electronic records that contain predictions of the outcome of the incident. The electronic records are conveyed (305) from the distributed domain (301) to the central domain (303). After the outcome of the incident is known, the central domain (303) finds out (306) which of the electronic records, if any, contain correct predictions of the outcome of the incident. Each of the electronic records is furnished (304, 401, 502, 902, 1202, 1911), within the distributed domain (301), with a cryptographically protected proof of a certain moment of time associated with the generation of the electronic record. The central domain (303) accepts (306, 1430, 2011) only those of the electronic records conveyed thereto as valid for which the cryptographically protected proof of a certain moment of time associated with the generation of the electronic record shows that said certain moment of time was not later in time than a certain time limit.

Methods and arrangements for realising betting with off-line terminals

This paper describes the core functionality and a proof-of-concept demonstration setup for remote 360 degree stereo virtual reality (VR) gaming. In this end-to-end scheme, the execution of a VR game is off-loaded from an end user device to a cloud edge server in which the executed game is rendered based on user's field of view (FoV) and control actions. Headset and controller feedback is transmitted over the network to the server from which the rendered views of the game are streamed to a user in real-time as encoded HEVC video frames. This approach saves energy and computation load of the end terminals by making use of the latest advancements in network connection speed and quality. In the showcased demonstration, a VR game is run in Unity on a laptop powered by i7 7820HK processor and GTX 1070 GPU. The 360 degree spherical view of the game is rendered and converted to a rectangular frame using equirectangular projection (ERP). The ERP video is sliced vertically and only the FoV is encoded with Kvazaar HEVC encoder in real time and sent over the network in UDP packets. Another laptop is used for playback with a HTC Vive VR headset. Our system can reach an end-to-end latency of 30 ms and bit rate of 20 Mbps for stereo 1080p30 format.

Timo Hämäläinen

Papers

A Wireless Sensor Network for RF-Based Indoor Localization

Flow-based Fast Handover method for Mobile IPv6 network

Ultra low energy wireless temperature sensor network implementation

Methods and arrangements for realising betting with off-line terminals

Low Latency Edge Rendering Scheme for Interactive 360 Degree Virtual Reality Gaming