Michimune Kohno

An adaptive sensor network system for complex environments

This paper describes the design and implementation of a sensor network system that can adapt to node failures and changes in node positions. The objective of this system is to support human actions in typical living and working environments such as buildings, offices, and homes. The adaptive sensor network system we designed and implemented can estimate the spatial position of each node, can detect a connection or disconnection between a node and the network, and can translate a position-based address into the appropriate set of sensor nodes. The evaluation results show the possibility of the system adapting to dynamic network changes.

Searching common experience: a social communication tool based on mobile ad-hoc networking

As small digital cameras become more popular, opportunities to take photos are rapidly increasing. Photo sharing is a great way to maintain and revitalize relationships between families and friends, and is a major motivator for content sharing. While photo sharing has been well studied, little work exists on sharing multiple photo sets contained in spontaneously connected handheld devices.This paper provides an algorithm to extract photos, based on common memories collected in an ad hoc group. It automatically searches for and presents photos that could become the starting point of a conversation. We found that our mechanism has more uses than simply organizing photos in chronological order.This paper describes our prototype system realized using the above algorithm. We also implemented a synchronized shutters mechanism, that provides a new photo sharing experience. Through subjective tests, we found that our method promotes conversation, even though the users did not know each other beforehand.

ProxNet: Secure Dynamic Wireless Connection by Proximity Sensing

This paper describes a method for establishing ad hoc and infrastructure-mode wireless network connections based on physical proximity. Users can easily establish secure wireless connections between two digital devices by putting them in close proximity to each other and pressing the connection button. The devices ”identify” each other by measuring each other’s signal strength. We designed a set of protocols to support secure connections between digital devices by using a proximity communication mode to exchange session keys. We also introduce a ”dummy point” that is analogous to a wireless access point but handles proximity-mode communication. The dummy point represents physical locations of digital devices and supports context-sensitive network communications.

Real-World Oriented Access Control Method with a Displayed Password

Access control within a ubiquitous networking environment is a critical issue. Traditional access control methods have mainly relied on the authentication of registered users or devices, and security issues arise if visitors are permitted to use networked resources in an office and have accessibility to other resources. We propose a new access control method that uses frequently changing passwords which are displayed beside the resource. This method provides real-world-oriented access control over an internet without any need for special hardware such as sensors.

Components of an adaptive sensor network

This paper describes the components and an addressing scheme for a sensor network in which the number and location of sensor nodes change dynamically. A sensor network is a network composed of various sensor nodes, and a sensor node consists of one or more CPUs, sensors, and a network interface. A sensor network, an organization of sensor nodes that are embedded in a wall, floor, electrical equipment, and nonelectrical equipment, can be used to support human action, the navigation of mobile robots, and other purposes. In comparison with a closed sensor network in a factory, they have the possibility to be moved somewhere without any notice given to the network management system. In order to operate such networks effectively and correctly, changes of the number and location of sensor nodes must be detected. In this paper, we discuss some fundamental components of such a network, and we call a network having these components an adaptive sensor network. They include position-based addressing, an addressing scheme that can be generally applicable to the construction of such sensor network systems. With this addressing scheme, a data value is requested by using not an identifier but a location. The client that requests the data does not care whether there is a real sensor node at the location or not. We created a prototype of an adaptive sensor network system. It consists of a node management system, a node positioning system, and a human interface system for the sensor network. Through performance evaluation of the prototype, we concluded that it could follow dynamic changes due to either node failures or the motion of nodes.

ShownPass: an easy access control with a displayed password

Access control is one of the most important issue with ubiquitous networking environment. Traditional access control methods are mainly considering authentication of registered user or device. Therefore, it is troublesome to allow a visitor to use a networked resource in an office, without accessiblity to other resources. We propose a new access control method using frequently changing passwords displayed beside a resource. This method can be implemented without any special hardware like a sensor.