Evolving controllers for a homogeneous system of physical robots: structured cooperation with minimal sensors

We report on recent work in which we employed artificial evolution to design neural network controllers for small, homogeneous teams of mobile autonomous robots. The robots were evolved to perform a formation-movement task from random starting positions, equipped only with infrared sensors. The dual constraints of homogeneity and minimal sensors make this a non-trivial task. We describe the behaviour of a successful system in which robots adopt and maintain functionally distinct roles in order to achieve the task. We believe this to be the first example of the use of artificial evolution to design coordinated, cooperative behaviour for real robots.     

Noise performance of erbium-doped fiber amplifier pumped at 1.49μm, and application to signal preamplification at 1.8 Gbit/s

Direct measurements of the noise figure of an erbium-doped fiber amplifier are described. With an amplifier gain as high as 36 dB, a noise figure as low as 4.1 dB was measured. Noise figures remained below 6 dB for signal wavelengths within the high gain (G>20 dB) region of the amplifier. An optical receiver sensitivity of -43 dBm at 1.8 Gb/s, corresponding to 215 photons/b, was achieved using the fiber amplifier as an optical preamplifier for a direct detection receiver     

Method for setting the absolute frequency of a tunable, 1.5 μmtwo-section DBR laser

A technique for setting the absolute frequency of a 1.5-μm two-section distributed Bragg reflector (DBR) laser using an Er:YAG optical filter as a frequency discriminator is described. The absolute frequency of the laser was controlled with an accuracy better than 300 MHz over a tuning range of several hundred gigahertz. The frequency drift with laser temperature was -130 MHz/°C, and the tuning rate with current in the active region was 40 MHz/mA     

Improving oral medication compliance with an electronic aid

Demographic trends indicate that populations in the U.S., Europe, and Japan are aging rapidly. As people age, they will seek more health-care services and ingest more oral medications. Poor compliance in taking medications is especially problematic in the elderly because of the changes in their metabolism, cognitive skills, and physical abilities. Simple devices, special packaging, and physical aids, while offering some improvement, do not appear able to answer this challenge. Drawbacks to such mechanical devices include their inability to accommodate multiple medications, their inability to remind patients when to take their medications, their inability to be easily reprogrammed for different dosage regimens, and their higher packaging costs. Electronic medication compliance dispensers, such as the MedMinder, appear to address many of these issues, but their true utility awaits definitive results from further development and clinical field trials     

Employee reactions to contextual and session components of performance appraisal.

A neglected area of performance appraisal research concerns the context within which the appraisal process occurs. For a sample of exempt employees, measures were developed that assessed system components of the appraisal context. The contribution of these variables (complexity, implementation, and follow-up) to the prediction of 2 measures of employee reactions to performance appraisal (review session satisfaction and appraisal system satisfaction) was compared with the contribution of a more frequently studied set of variables—supervisory behaviors in the review session. The relationship of a salary linkage variable to the 2 outcome criteria also was assessed. The supervisory session variables were related to session satisfaction, and the system contextual variables were primarily related to system satisfaction. Salary linkage was associated with system satisfaction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Influence of Race in Police–Civilian Interactions: A Content Analysis of Videotaped Interactions Taken During Cincinnati Police Traffic Stops

Although the study of police–civilian relations has recently entered the intergroup communication arena, there are no studies of actual interactions between these social categories. In part to rectify that stark omission and guided by communication accommodation theory, 313 randomly sampled video recordings from police cars on traffic stops in Cincinnati, Ohio were content analyzed. The study revealed 3 key differences as a function of the officers' and drivers' races: (a) Black drivers were more likely to experience extensive policing during the stop; (b) the communication quality of White drivers was, on average, more positive than that of the Black drivers; and (c) officers' communication behavior was more positive when the officer and driver were of the same race. These findings are consistent with public opinion data and their implications for theory are discussed.     

The essential role of gold in the fabrication of microwave electronics systems

Microwave technology will be the cornerstone of 21st Century electronics. Microwave electronics systems differ radically from conventional silicon semiconductor technology, requiring specialist semiconductors, circuits and interconnects. Gallium arsenide and gallium nitride are advanced compound semiconductors that fulfil the first requirement. Gold and gold alloys have unique properties that are essential for integrating these components into functioning systems.     

Optical-fibre surface-plasmon-wave polarisers with enhanced performance

The effect of a thin metal film with positive dielectric permittivity on the performance of an optical-fibre surface-plasmon-wave polariser is presented. A dramatic improvement has been achieved with polarisation extinction ratios in excess of 45 dB over an extended range of superstrate refractive indices.<>     

Process modeling for advanced device technologies

Front end process simulation is an invaluable tool in assessing current and future process options. This review describes the application of process simulation in modeling geometry, doping and stress effects in advanced logic processes. Continuum and atomistic approaches, both necessary to capture the physics involved with the most advanced options, are discussed. Also detailed are advancements in numerical techniques which enable the efficient and robust simulation necessary to keep pace with technology development.     

Erosion of drawing as a thinking and collaborative tool

The Building Research & Information special issue on ‘Visual Practices: Images of Knowledge Work’ (2007) begins to unravel the complex uses of knowledge embodied within artefacts such as drawings and the use of these artefacts in the wider social contexts of sharing and negotiating knowledge. However, there are some central questions about the changing nature of working practices and the complex functions ascribed to visual artefacts. The declining use of drawing and the rising use of computer-aided design (CAD) and information technology (IT) require further understanding, particularly for the social and organizational aspects of working within a design team and engaging with ‘outside’ stakeholders. Within the design office, the use of CAD systems may inhibit crucial peer conversations and interactions as well as limit the iterative working process when compared with the drawing process. Outside the design office, does the finished quality of CAD documents encourage dialogue, understanding, flexibility and openness with stakeholders (especially users) when compared with other forms of drawing? The act of drawing is an intellectual activity that embraces both analysis (understanding) and conception (proposition). Can CAD offer a similar level of richness or is there a loss in capabilities for those without drawing skills? Further research is needed, along the lines initiated in this special issue, to understand better the impacts and limitations imposed by the isolation of working behind a computer monitor.

Le numéro spécial de Building Research & Information consacré aux ‘Visual Practices: Images of Knowledge Work’ (2007) commence par dévoiler les usages complexes de la connaissance intégrée dans des artefacts, comme les dessins et l'usage de ces artefacts dans le contexte social plus large du partage et de la négociation de la connaissance. Il demeure cependant un certain nombre de questions centrales concernant la nature changeante des pratiques de travail et les fonctions complexes attribuées aux artefacts visuels. Le déclin du dessin au profit de la conception assistée par ordinateur (CAO) et le recours croissant aux technologies de l'information (TI) exigent un complément de compréhension, en particulier pour ce qui est des aspects sociaux et organisationnels du travail au sein d'une équipe de conception et un engagement avec des intervenants extérieurs. Au sein du bureau d'étude, l'utilisation de systèmes de CAO peut inhiber les conversations et les interactions si importantes entre collègues et limiter aussi le processus itératif comparé au dessin. En dehors du bureau d'étude, la qualité finale des documents CAO encourage-t-elle le dialogue, la compréhension, la souplesse et l'ouverture des intervenants (en particulier les utilisateurs) par rapport à d'autres formes de dessin? Le dessin est une activité intellectuelle qui englobe à la fois l'analyse (compréhension) et la conception (proposition). La CAO peut-elle offrir un même niveau de richesse ou bien y a-t-il une perte de capacité pour ceux qui ne possèdent pas de compétences de dessinateur? Il convient de mener d'autres recherches le long des axes présentés dans ce numéro spécial afin de mieux comprendre les incidences et les limitations imposées par l'isolement que constitue le travail derrière un écran d'ordinateur.

communication,?pratiques de la conception,?procédures de la conception,?dessin,?pratiques professionnelles,?représentation visuelle,?visualisation