Multi-sensor Devices Research Articles

The reflective mobile agent paradigm implemented in a smart office environment

Ubiquitous systems will integrate computers invisibly and unobtrusively in everyday objects. Data will be catched from single or multi-sensor devices and will be used for context extraction. New location-based services will be adapted to user preferences. For this the ubiquitous system needs to know user profiles, likings, and habits. As the user moves, these information must be made available at the new location of the user. Either the user carries the data on wearable or portable computers or the smart environment takes responsibility for transporting them. The amount of new devices and services makes an efficient use by centralized systems very difficult. The idea presented in this paper is that a virtual reflection of the user represented by a mobile agent accompanying in the smart environment. Mobile agents offer a possibility to encapsulate information of a person and the person’s preferences and perform location-based services of the ubiquitous system in the name of the user. Security and privacy are major concerns of such an agent system. This paper describes a ubiquitous mobile agent system named UbiMAS which has security extensions to provide high protection of agents and significant personal data. UbiMAS is applied in the smart doorplate project as part of a smart office environment.

Cross-sensitivity evaluation of chemical sensors for electronic tongue: determination of heavy metal ions

The development of the promising new field of sensor applications, multisensor arrays for liquid analysis based on the principles of the electronic tongue, implies some new demands on sensor material research and development. Stable and reproducible sensors with partial specificity and considerable cross-sensitivities to different components in solutions are of primary interest. Solid-state potentiometric sensors, both crystalline and vitreous, are likely to be the most promising ones for multisensor devices designed for long-term analytical application in natural and artificial complex media. The present paper deals with development of a method of evaluation of integral heavy metal cation sensitivity of solid-state sensors with special consideration of cross-sensitivity features. The method involves a comparative study of different sensor materials in individual component solutions, using several criteria based on integral response parameters. The procedure scheme can be applied to evaluate cross-sensitivity of any kind of potentiometric sensors for liquid media.

Waveguide surface plasmon resonance sensors

Guided-wave optical biosensors have great potential for use in the field of environmental monitoring. In particular, planar waveguide technologies offer the possibility of producing compact, monolithic, multisensor devices which may be connected to instrumentation using optical fibres, allowing remote operation. Optical evanescent field sensing techniques presently under investigation include grating couplers, waveguide interferometers and surface plasmon resonance (SPR) sensors. In the latter case, the surface plasmon is generally excited using a bulk optical component such as a prism, and equipment using this technique is now commercially available. One potential advantage of the SPR technique is that the metal film which supports the surface plasmon may also be used as an electrode for electrochemical control of sensing reactions. However, recent reports have indicated that the bulk SPR devices may not ultimately be as sensitive as fully guided-wave approaches such as the Mach-Zehnder interferometer. An alternative to the bulk SPR devices which has recently emerged is the use of distributed coupling between a dielectric waveguide and the surface plasmon mode in a metal-coated waveguide. This has the advantage of combining greater design flexibility and the potential for monolithic integration with the well-established technique of SPR. However, at present no adequate model for the performance of these devices exists. ...