Heikki Waris

Key Properties in the Development of Smart Spaces

This paper is targeted at improving and expanding the understanding of the Smart Spaces concept of by the R&D community. Through the identification of key properties based on an analysis of evolving trends in the mobile industry, the developers are provided with recommendations that improve the adoption of Smart Spaces. It is especially important to understand how Smart Spaces can change the whole services ecosystem and the role that mobile devices will play. The paper discusses some core technologies being developed in the industry that might play a dominant role in the future Smart Spaces. A special attention of the discussion is the latest trend towards a networked inter-device architecture for mobile devices and what new possibilities it opens. With that the discussion expands into general properties of Smart Spaces. The paper summarizes functional and non-functional properties. By understanding the properties and their implications to the development and adoption of Smart Spaces, the developers are better equipped to ensure that the needs of the various stakeholders are taken into account. For this purpose, the paper proposes a set of questions that can be used to estimate how well the planned Smart Space fares when compared against each of the properties.

Performance measurements and analysis of TCP flows in a differentiated services WAN

This paper presents results from performance measurements carried out in a differentiated services WAN connecting three major cities in southern Finland. The target of the measurements was to collect precise information about the level of service experienced by a user transmitting files with FTP in a network that implements service differentiation by using drop precedence levels and separate classes for real time and non-real time traffic. Special attention was paid to the behaviour of competing TCP flows produced by users with different service level specifications. Background traffic from ISPs network was injected into our test network in order to create traffic profiles which are typical in a core network. The results show clearly that the SIMA model used for the implementation of the DS mechanisms in the network nodes can provide service differentiation in a useful and fair manner in traffic conditions varying from light load to severe overload.

TLS and energy consumption on a mobile device: A measurement study

We report results from a measurement study on the role of the most popular end-to-end security protocol Transport Layer Security (TLS) in the energy consumption of a mobile device. We measured energy consumed by TLS transactions between a Nokia N95 and several popular Web services over WLAN and 3G network interfaces. Our detailed analysis corroborates some earlier results but also reveals, contrary to earlier studies, that the transmission and I/O energy, both in the TLS handshake and the record protocol, far exceed the required computational energy by the actual cryptographic algorithms and that with transactions larger than 500KB, the energy required to transmit the actual data clearly outranks the TLS energy overhead. In addition, we note that the energy consumption varies remarkably between measured services.

Increasing broker performance in smart-M3 based ridesharing system

Ridesharing is one of the most cost effective alternative transportation modes with high potential in reducing the greenhouse gas emissions and decreasing the amount of traffic in the streets. The paper extends the earlier presented approach to building sustainable logistics system for ridesharing support based on the idea of smart spaces, where various electronic devices can seamlessly access all required information distributed in the multidevice system from any of the devices. In particular, the paper describes broker as a main component of the system and algorithms used for its performance optimization. The Smart-M3 open source platform was chosen as a basis for the proposed approach.

Development of broker logic for ridesharing system on top of Smart-M3

Ridesharing is attracting more and more attention due to its high potential for applying new business models to private transportation in urban areas, reducing the greenhouse gas emissions and decreasing the amount of traffic on the streets. The paper extends the earlier presented approaches of building sustainable logistics system that support ridesharing by applying to it principles of smart spaces, where various electronic devices can seamlessly access all required information distributed in the multi-device system and all services are provided in pro-active manner. In particular, the paper describes the ontology and major components for the ridesharing system. An example implementation of the developed solution was done on top of Smart-M3 open source platform.