Cybernetic automata: An approach for the realization of economical cognition for multi-robot systems

The multi-agent robotics paradigm has attracted much attention due to the variety of pertinent applications that are well-served by the use of a multiplicity of agents (including space robotics, search and rescue, and mobile sensor networks). The use of this paradigm for most applications, however, demands economical, lightweight agent designs for reasons of longer operational life, lower economic cost, faster and easily-verified designs, etc. An important contributing factor to an agent’s cost is its control architecture. Due to the emergence of novel implementation technologies carrying the promise of economical implementation, we consider the development of a technology-independent specification for computational machinery. To that end, the use of cybernetics toolsets (control and dynamical systems theory) is appropriate, enabling a principled specifi- cation of robotic control architectures in mathematical terms that could be mapped directly to diverse implementation substrates. This dissertation, hence, addresses the problem of developing a technologyindependent specification for lightweight control architectures to enable robotic agents to serve in a multi-agent scheme. We present the principled design of static and dynamical regulators that elicit useful behaviors, and integrate these within an overall architecture for both single and multi-agent control. Since the use of control theory can be limited in unstructured environments, a major focus of the work is on the engineering of emergent behavior. The proposed scheme is highly decentralized, requiring only local sensing and no inter-agent communication. Beyond several simulation-based studies, we provide experimental results for a two-agent system, based on a custom implementation employing field-programmable gate arrays

Distribution and conservation of small carnivores focussing on the Bornean endemic Hose's civet

The aim of this study was to improve our understanding of the ecology and distribution of Borneo’s carnivores at different spatial scales, from the local scale to a coarse-scale Borneo-wide perspective. A particular emphasis was placed on the highland endemic Hose’s civet. The objectives of this thesis were to: 1) Use Hose’s civet as a case study of a little-studied highland endemic to assess habitat requirements, distribution and threats across Borneo under current and future environmental change scenarios, thereby identifying key aspects and locations for targeted conservation interventions. As an example of a tropical highland endemic, this study also sought to evaluate whether such species are particularly vulnerable to the effects of climate change, and therefore, to what extent scenarios for future climate change should be considered when formulating conservation management strategies. 2) Understand fine-scale predictors of small carnivore occurrence within the disturbed and modified habitat of a logging concession in Sarawak. This improved understanding could then be translated into management recommendations to enhance carnivore conservation in logging concessions across Sarawak. 3) Identify priority conservation landscapes for carnivores across Borneo, and questions for research and conservation which need more attention. This understanding will hopefully facilitate systematic, holistic conservation planning for Borneo’s diverse carnivore community, provide an evidence base for conservation planning and bridge the gap between conservation research and practise

Effects of fiber on the optimum threonine:lysine ratio for 25 to 50 kg growing gilts

Five experiments were conducted to determine the ideal Thr:Lys ratio for 25 to 50 kg growing gilts and the effects of fiber on said ratio. In Exp. 1, the objectives were to determine the standardized ileal digestible (SID) Lys requirement for gilts from 25 to 50 kg BW. Seventy gilts (initial BW: 24.54 ± 3.28 kg) were used in a growth assay with 2 pigs per pen and 7 pens per treatment. Diets were formulated using corn and soybean meal as the sole sources of AA. Under the assumption that Lys is the first limiting AA in corn-soybean meal diets, soybean meal concentration was increased at the expense of corn to increase SID Lys in the diets. Results indicated that 1.08% SID Lys was needed to maximize ADG and 1.10% SID Lys was needed to maximize G:F. In Exp. 2, the objectives were to determine the standardized ileal digestibility of AA in corn, soybean meal, field peas, fish meal, and soybean hulls. These ingredients were chosen because of their unique AA profiles, which facilitate their use diets that are deficient in only Lys and Thr. Six ileal-cannulated gilts (initial BW: 26.5 ± 0.74 kg) were allotted to a 6 × 6 Latin square design with 6 diets and 6 periods. The results indicated that the standardized ileal digestibility of most indispensable AA was not different among field peas, fish meal, and soybean meal, whereas the standardized ileal digestibility of some indispensable AA was less in soybean hulls than in other ingredients. In Exp. 3, the objectives were to confirm that diets deficient in only Thr and Lys can be formulated. One hundred twenty gilts (initial BW: 24.84 ± 3.39 kg) were allotted to either low fiber or high fiber diets. Within each level of fiber, the 5 different diets were formulated by changing the proportion of synthetic Thr and Lys in the diets. Resulting differences in ADG, ADFI, and G:F between diets indicated that the diets were marginally deficient in Lys and Thr. In Exp. 4, the objectives were to determine the optimal SID Thr:Lys ratio for gilts from 25 to 50 kg BW, and to determine the effects of fiber on that ratio. One hundred ninety-two gilts were used in a growth assay with 2 pigs per pen and 8 pens per treatment. Low-fiber, as well as high-fiber, diets with SID Thr:Lys ratios at 45:100, 54:100, 63:100, 72:100, 81:100, and 90:100 were used. In both types of diets ADG and G:F increased quadratically (P < 0.05), as the concentration of Thr increased in the diets. For pigs fed the low-fiber diets, combined broken-line and quadratic analyses estimated the optimum SID Thr:Lys ratio at 0.66 and 0.63 for ADG and G:F, respectively. For the pigs fed high fiber diets, combined broken-line quadratic analyses estimated the optimum SID Thr:Lys requirement at 0.71 and 0.63 for ADG and G:F, respectively. In Exp. 5, the objective was to confirm the results of Exp. 4 by determining N balance in pigs fed either low-fiber or high-fiber diets that were deficient or adequate in Thr. Thirty-six growing gilts (initial BW: 29.0 ± 0.74 kg) were housed in metabolism cages and there were 9 replicates per diet. Output of N in feces was greater (P < 0.05) from pigs fed high-fiber diets, but output of N in urine was greater (P < 0.05) from pigs fed low-fiber diets. The ATTD of N was greater (P < 0.05) from pigs fed low-fiber diets than in pigs fed high-fiber diets, and retention of N was greater (P < 0.05) in pigs fed low-fiber diets than in pigs fed high-fiber diets. There was greater (P < 0.05) N retention in pigs fed high-Thr diets compared with pigs fed low-fiber diets. There was also an interaction (P < 0.05) between fiber level and Thr for output of N in feces with N output increasing (P < 0.05) as Thr in the high-fiber diet increased, whereas this was not the case for the low-fiber diet. Results indicate that higher fiber diets may require greater concentrations of Thr. In conclusion, results of these experiments indicate that increased fiber levels in diets fed to growing gilts may increase the requirement for Thr and diets with higher fiber levels should include a greater concentration of Thr

Wake-Driven Dynamics of Finite-Sized Buoyant Spheres in Turbulence

Particles suspended in turbulent flows are affected by the turbulence and at the same time act back on the flow. The resulting coupling can give rise to rich variability in their dynamics. Here we report experimental results from an investigation of finite-sized buoyant spheres in turbulence. We find that even a marginal reduction in the particle's density from that of the fluid can result in strong modification of its dynamics. In contrast to classical spatial filtering arguments and predictions of particle models, we find that the particle acceleration variance increases with size. We trace this reversed trend back to the growing contribution from wake-induced forces, unaccounted for in current particle models in turbulence. Our findings highlight the need for improved multi-physics based models that account for particle wake effects for a faithful representation of buoyant-sphere dynamics in turbulence.Comment: 5 pages, 4 figures, http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.115.12450

Psychopathology in patients with psoriasis: a cross-sectional clinical study

Background: Psoriasis is associated with a variety of psychological problems including poor self-esteem, sexual dysfunction, anxiety and depressive disorder and suicidal ideation. There are reports that patients with psoriasis may have significant psychiatric morbidity. The objective of the study is to evaluate the frequency of psychiatric disorders, frequency and nature of psychiatric symptoms in patients with psoriasis.Methods: 100 patients with psoriasis were evaluated and included for the study. Comprehensive Psychopathological Rating Scale (CPRS) is used for assessment of psychiatric symptoms and MINI Plus for assessing psychiatric disorders. Chi-square test was used to compare the proportions.Results: Patients with psoriasis had high frequency of psychiatric morbidity and was found to be 42%.Conclusions: Patients with psoriasis have more psychopathology and higher psychiatric morbidity which may further imply justifiable consultation liaison psychiatry in other speciality fields like Dermatology

Recombinant Activated Factor VII (rFVIIa) in the Management of Major Obstetric Haemorrhage: A Case Series and a Proposed Guideline for Use

Major obstetric haemorrhage remains a significant cause of maternal morbidity and mortality. Previous case reports suggest the potential benefit of recombinant activated factor VII (rFVIIa: NovoSevenR) as a haemostatic agent. We performed a retrospective review of the use of rVIIa in major obstetric haemorrhage in the Northern Region between July 2004 and February 2007. Fifteen women received rFVIIa. The median patient age was 34 years. Major haemorrhage occurred antepartum (5 patients), intrapartum (1), and postpartum (9). All women received an initial dose of 90 mcg/kg rFVIIa and one received 2 further doses. Bleeding stopped or decreased in 12 patients (80%). Additional measures included antifibrinolytic and uterotonic agents, Rusch balloon insertion, uterine curettage/packing, and vessel embolisation. Eight patients required hysterectomy. All women survived to discharge from hospital. No adverse events, including thrombosis, were recorded. This study provides further support for the safety and efficacy of rFVIIa as adjunct therapy in major obstetric haemorrhage