95,423 research outputs found
Modelling of Multi-Agent Systems: Experiences with Membrane Computing and Future Challenges
Formal modelling of Multi-Agent Systems (MAS) is a challenging task due to
high complexity, interaction, parallelism and continuous change of roles and
organisation between agents. In this paper we record our research experience on
formal modelling of MAS. We review our research throughout the last decade, by
describing the problems we have encountered and the decisions we have made
towards resolving them and providing solutions. Much of this work involved
membrane computing and classes of P Systems, such as Tissue and Population P
Systems, targeted to the modelling of MAS whose dynamic structure is a
prominent characteristic. More particularly, social insects (such as colonies
of ants, bees, etc.), biology inspired swarms and systems with emergent
behaviour are indicative examples for which we developed formal MAS models.
Here, we aim to review our work and disseminate our findings to fellow
researchers who might face similar challenges and, furthermore, to discuss
important issues for advancing research on the application of membrane
computing in MAS modelling.Comment: In Proceedings AMCA-POP 2010, arXiv:1008.314
Simulating activities: Relating motives, deliberation, and attentive coordination
Activities are located behaviors, taking time, conceived as socially meaningful, and usually involving interaction with tools and the environment. In modeling human cognition as a form of problem solving (goal-directed search and operator sequencing), cognitive science researchers have not adequately studied “off-task” activities (e.g., waiting), non-intellectual motives (e.g., hunger), sustaining a goal state (e.g., playful interaction), and coupled perceptual-motor dynamics (e.g., following someone). These aspects of human behavior have been considered in bits and pieces in past research, identified as scripts, human factors, behavior settings, ensemble, flow experience, and situated action. More broadly, activity theory provides a comprehensive framework relating motives, goals, and operations. This paper ties these ideas together, using examples from work life in a Canadian High Arctic research station. The emphasis is on simulating human behavior as it naturally occurs, such that “working” is understood as an aspect of living. The result is a synthesis of previously unrelated analytic perspectives and a broader appreciation of the nature of human cognition. Simulating activities in this comprehensive way is useful for understanding work practice, promoting learning, and designing better tools, including human-robot systems
Engineering simulations for cancer systems biology
Computer simulation can be used to inform in vivo and in vitro experimentation, enabling rapid, low-cost hypothesis generation and directing experimental design in order to test those hypotheses. In this way, in silico models become a scientific instrument for investigation, and so should be developed to high standards, be carefully calibrated and their findings presented in such that they may be reproduced. Here, we outline a framework that supports developing simulations as scientific instruments, and we select cancer systems biology as an exemplar domain, with a particular focus on cellular signalling models. We consider the challenges of lack of data, incomplete knowledge and modelling in the context of a rapidly changing knowledge base. Our framework comprises a process to clearly separate scientific and engineering concerns in model and simulation development, and an argumentation approach to documenting models for rigorous way of recording assumptions and knowledge gaps. We propose interactive, dynamic visualisation tools to enable the biological community to interact with cellular signalling models directly for experimental design. There is a mismatch in scale between these cellular models and tissue structures that are affected by tumours, and bridging this gap requires substantial computational resource. We present concurrent programming as a technology to link scales without losing important details through model simplification. We discuss the value of combining this technology, interactive visualisation, argumentation and model separation to support development of multi-scale models that represent biologically plausible cells arranged in biologically plausible structures that model cell behaviour, interactions and response to therapeutic interventions
Cognitive modeling of social behaviors
To understand both individual cognition and collective activity, perhaps the greatest opportunity today is to integrate the cognitive modeling approach (which stresses how beliefs are formed and drive behavior) with social studies (which stress how relationships and informal practices drive behavior). The crucial insight is that norms are conceptualized in the individual mind as ways of carrying out activities. This requires for the psychologist a shift from only modeling goals and tasks —why people do what they do—to modeling behavioral patterns—what people do—as they are engaged in purposeful activities. Instead of a model that exclusively deduces actions from goals, behaviors are also, if not primarily, driven by broader patterns of chronological and located activities (akin to scripts).
To illustrate these ideas, this article presents an extract from a Brahms simulation of the Flashline Mars Arctic Research Station (FMARS), in which a crew of six people are living and working for a week, physically simulating a Mars surface mission. The example focuses on the simulation of a planning meeting, showing how physiological constraints (e.g., hunger, fatigue), facilities (e.g., the habitat’s layout) and group decision making interact. Methods are described for constructing such a model of practice, from video and first-hand observation, and how this modeling approach changes how one relates goals, knowledge, and cognitive architecture. The resulting simulation model is a powerful complement to task analysis and knowledge-based simulations of reasoning, with many practical applications for work system design, operations management, and training
Telerobotic workstation design aid
Telerobot systems are being developed to support a number of space mission applications. In low earth orbit, telerobots and teleoperated manipulators will be used in shuttle operations and space station construction/maintenance. Free flying telerobotic service vehicles will be used at low and geosynchronous orbital operations. Rovers and autonomous vehicles will be equipped with telerobotic devices in planetary exploration. In all of these systems, human operators will interact with the robot system at varied levels during the scheduled operations. The human operators may be in either orbital or ground-based control systems. To assure integrated system development and maximum utility across these systems, designers must be sensitive to the constraints and capabilities that the human brings to system operation and must be assisted in applying these human factors to system development. The simulation and analysis system is intended to serve the needs of system analysis/designers as an integrated workstation in support of telerobotic design
Application of palm shell activated carbon filter as a medium of indoor air contaminant adsorbent for indoor air quality improvement
For decades, the inclusion of activated carbon (AC) adsorption technique through
filtration has gained significant interest on improvement of indoor air quality (IAQ)
by reducing level of pollutant. The interest of reseachers in palm shell AC (PSAC)
keep increase owing to the fact that this material has superior characteristic as
compared to commercial AC. However, the investigation of PSAC performance for
air filtration are still limited and no research could be found on relating the effect of
burner for carbonization on PSAC properties. Therefore, the current research was
focused on producing PSAC by using new fabricated burner, exploring the effect of
combination of physical and chemical activation towards PSAC properties and
investigating of PSAC air filter performance used in Mechanical Ventilation Air
Conditioning (MVAC) system. Preliminary studies began with IAQ monitoring in
different building condition. The present data revealed that at certain situation, the
buildings environment was below than satisfactory level and required mitigation plan
by introducing new air filtration media in MVAC system. The best quality of charcoal
was obtained by Horizontal burner with less fume formation during carbonization
process compare to other design. The physical properties analysis of palm shell
charcoal showed the carbonization time (CT) 2 hours gained better charcoal properties
and highly recommended to continue into the activation process. After the activation
process, PSAC physical+chemical shows significantly higher pore development,
surface area and adsorption capacity compare to the other process. The lowest density
and the highest porosity up to 0.4632 g/cm
and 7.11% was calculated while the
highest Iodine number of 1091.05 mg/g and BET surface area of 713.7 m
3
/g was
obtained respectively in PSAC physical+chemical. Meanwhile, microstructure and
composition analysis shows that, PSAC physical+chemical fully produced honeycomb
form of porosity and comprised of C, O, K and Ca contents for high adsorption
capacity. The improvement of IAQ in the buildings was achieved with the application
of PSAC air filter which shows low concentration of CO2 with 302 ppm, CO with 0.4
ppm , TVOC with 0.1 ppm and PM10 with 0.02mg/m
2
respectively compare to the
commercial filter
Development of limiting dilution viability pcr method to assess the effectiveness of selected biocides to treat indoor fungi growth
Indoor fungal contamination should be treated with cost-effective and green methods.
Biocides have direct biological effect on living organisms but the evidence on their
control of indoor fungal contamination is scarce. Using conventional cultivation to
evaluate their effectiveness is time consuming while polymerase chain reaction (PCR)
provides a fast and reliable alternative. The incorporation of serial dilution technique
and viability information in PCR has made it suitable to evaluate the effectiveness of
biocides. Thus, this study aimed to assess the antifungal ability of biocides, zinc
salicylate (ZS), calcium benzoate (CB) and potassium sorbate (KS) to treat indoor
fungal contamination through developing limiting dilution viability PCR (vPCR).
These biocides were selected as they successfully controlled the growth of indoor
waterborne fungi previously. Indoor air sampling revealed that higher educational
building of computer studies (Building A) and of civil engineering studies (Building
B) were contaminated by 509 CFU/m3 and 805.7 CFU/m3 of indoor airborne fungi,
respectively. Two indoor fungi, Talaromyces spp. and Aspergillus niger were
identified. They were subjected to biocides-treatment and subsequent conventional
cultivation and limiting dilution vPCR due to their potential risks against humans’
health. The limiting dilution vPCR was developed by incorporating the pre-treatment
of propidium monoazide (PMA) before deoxyribonucleic acid (DNA) extraction and
the serial dilution of the DNA template in PCR. This approach was proven to
effectively enumerate the effectiveness of biocides to treat indoor fungi. KS was
shown to have the best effectiveness (100%) to prevent the growth of Talaromyces
spp, followed by ZS (80.8%) and CB (no effect). KS also showed the best
effectiveness against A. niger (100%) at the early stage of the study but its effect
reduced with time. ZS showed durable effect (66.67%) against A. niger Day 9
cultures. Inconstant results were indicated by cultivation method. This study has
provided a cheaper, more accurate and suitable approach to determine the
effectiveness of treatment of indoor fungi than cultivation methods
A Self-Organizing Neural Model of Motor Equivalent Reaching and Tool Use by a Multijoint Arm
This paper describes a self-organizing neural model for eye-hand coordination. Called the DIRECT model, it embodies a solution of the classical motor equivalence problem. Motor equivalence computations allow humans and other animals to flexibly employ an arm with more degrees of freedom than the space in which it moves to carry out spatially defined tasks under conditions that may require novel joint configurations. During a motor babbling phase, the model endogenously generates movement commands that activate the correlated visual, spatial, and motor information that are used to learn its internal coordinate transformations. After learning occurs, the model is capable of controlling reaching movements of the arm to prescribed spatial targets using many different combinations of joints. When allowed visual feedback, the model can automatically perform, without additional learning, reaches with tools of variable lengths, with clamped joints, with distortions of visual input by a prism, and with unexpected perturbations. These compensatory computations occur within a single accurate reaching movement. No corrective movements are needed. Blind reaches using internal feedback have also been simulated. The model achieves its competence by transforming visual information about target position and end effector position in 3-D space into a body-centered spatial representation of the direction in 3-D space that the end effector must move to contact the target. The spatial direction vector is adaptively transformed into a motor direction vector, which represents the joint rotations that move the end effector in the desired spatial direction from the present arm configuration. Properties of the model are compared with psychophysical data on human reaching movements, neurophysiological data on the tuning curves of neurons in the monkey motor cortex, and alternative models of movement control.National Science Foundation (IRI 90-24877); Office of Naval Research (N00014-92-J-1309); Air Force Office of Scientific Research (F49620-92-J-0499); National Science Foundation (IRI 90-24877
Multiple roles of motor imagery during action observation
Over the last 20 years, the topics of action observation (AO) and motor imagery (MI) have been largely studied in isolation from each other, despite the early integrative account by Jeannerod (1994, 2001). Recent neuroimaging studies demonstrate enhanced cortical activity when AO and MI are performed concurrently (“AO+MI”), compared to either AO or MI performed in isolation. These results indicate the potentially beneficial effects of AO+MI, and they also demonstrate that the underlying neurocognitive processes are partly shared. We separately review the evidence for MI and AO as forms of motor simulation, and present two quantitative literature analyses that indeed indicate rather little overlap between the two bodies of research. We then propose a spectrum of concurrent AO+MI states, from congruent AO+MI where the contents of AO and MI widely overlap, over coordinative AO+MI, where observed and imagined action are different but can be coordinated with each other, to cases of conflicting AO+MI. We believe that an integrative account of AO and MI is theoretically attractive, that it should generate novel experimental approaches, and that it can also stimulate a wide range of applications in sport, occupational therapy, and neurorehabilitation
- …