The ART of IAM: The Winning Strategy for the 2006 Competition

In many dynamic open systems, agents have to interact with one another to achieve their goals. Here, agents may be self-interested, and when trusted to perform an action for others, may betray that trust by not performing the actions as required. In addition, due to the size of such systems, agents will often interact with other agents with which they have little or no past experience. This situation has led to the development of a number of trust and reputation models, which aim to facilitate an agent's decision making in the face of uncertainty regarding the behaviour of its peers. However, these multifarious models employ a variety of different representations of trust between agents, and measure performance in many different ways. This has made it hard to adequately evaluate the relative properties of different models, raising the need for a common platform on which to compare competing mechanisms. To this end, the ART Testbed Competition has been proposed, in which agents using different trust models compete against each other to provide services in an open marketplace. In this paper, we present the winning strategy for this competition in 2006, provide an analysis of the factors that led to this success, and discuss lessons learnt from the competition about issues of trust in multiagent systems in general. Our strategy, IAM, is Intelligent (using statistical models for opponent modelling), Abstemious (spending its money parsimoniously based on its trust model) and Moral (providing fair and honest feedback to those that request it)

TRAVOS: Trust and Reputation in the Context of Inaccurate Information Sources

In many dynamic open systems, agents have to interact with one another to achieve their goals. Here, agents may be self-interested, and when trusted to perform an action for another, may betray that trust by not performing the action as required. In addition, due to the size of such systems, agents will often interact with other agents with which they have little or no past experience. There is therefore a need to develop a model of trust and reputation that will ensure good interactions among software agents in large scale open systems. Against this background, we have developed TRAVOS (Trust and Reputation model for Agent-based Virtual OrganisationS) which models an agent's trust in an interaction partner. Specifically, trust is calculated using probability theory taking account of past interactions between agents, and when there is a lack of personal experience between agents, the model draws upon reputation information gathered from third parties. In this latter case, we pay particular attention to handling the possibility that reputation information may be inaccurate

Trace gas transport in the subsurface of Mars

The ExoMars Trace Gas Orbiter (TGO) will have the capability of detecting and characterizing a broad suite of trace gases in the atmosphere of Mars. Interpreting the results of this mission will require an understanding of how these trace gases are transported from their sources, which may be deep underground, to the atmosphere. Here we present results of modeling designed to measure the timescales of release from putative subsurface methane sources. These transport timescales are far longer than mixing times in the atmosphere and could be up to 10 million years

Improving dialysis adherence for high risk patients using automated messaging: Proof of concept

AbstractComorbidities and socioeconomic barriers often limit patient adherence and self-management with hemodialysis. Missed sessions, often associated with communication barriers, can result in emergency dialysis and avoidable hospitalizations. This proof of concept study explored using a novel digital-messaging platform, EpxDialysis, to improve patient-to-dialysis center communication via widely available text messaging and telephone technology. A randomized controlled trial was conducted through Washington University-affiliated hemodialysis centers involving ESRD patients with poor attendance, defined as missing 2–6 sessions over the preceding 12 weeks. A cross-over study design evaluated appointment adherence between intervention and control groups. Comparing nonadherence rates eight weeks prior to enrollment, median appointment adherence after using the system increased by 75%, and median number of unintended hospitalization days fell by 31%. A conservative cost-benefit analysis of EpxDialysis demonstrates a 1:36 savings ratio from appointment adherence. EpxDialysis is a low-risk, cost-effective, intervention for increasing hemodialysis adherence in high-risk patients, especially at centers caring for vulnerable and low-income patients.</jats:p

Activation of the P2Y2 receptor regulates bone cell function by enhancing ATP release

Bone cells constitutively release ATP into the extracellular environment where it acts locally via P2 receptors to regulate bone cell function. Whilst P2Y2 receptor stimulation regulates bone mineralisation, the functional effects of this receptor in osteoclasts remain unknown. This investigation used the P2Y2 receptor knockout (P2Y2R−/−) mouse model to investigate the role of this receptor in bone. MicroCT analysis of P2Y2R−/− mice demonstrated age-related increases in trabecular bone volume (≤48%), number (≤30%) and thickness (≤17%). In vitro P2Y2R−/− osteoblasts displayed a 3-fold increase in bone formation and alkaline phosphatase activity, whilst P2Y2R−/− osteoclasts exhibited a 65% reduction in resorptive activity. Serum cross-linked C-telopeptide levels (CTX, resorption marker) were also decreased (≤35%). The resorption defect in P2Y2R−/− osteoclasts was rescued by the addition of exogenous ATP, suggesting that an ATP deficit could be a key factor in the reduced function of these cells. In agreement, we found that basal ATP release was reduced up to 53% in P2Y2R−/− osteoclasts. The P2Y2 receptor agonists, UTP and 2-thioUTP, increased osteoclast activity and ATP release in wild-type but not in P2Y2R−/− cells. This indicates that the P2Y2 receptor may regulate osteoclast function indirectly by promoting ATP release. UTP and 2-thioUTP also stimulate ATP release from osteoblasts suggesting that the P2Y2 receptor exerts a similar function in these cells. Taken together, our findings are consistent with the notion that the primary action of P2Y2 receptor signalling in bone is to regulate extracellular ATP levels

Mars simulated exposure and the characteristic Raman biosignatures of amino acids and halophilic microbes

Though Raman bands of α-amino acids (AA) are well documented, often only the strongest intensity bands are quoted as identifiers (e.g. Jenkins et al., 2005; De Gelder et al., 2007; Zhu et al., 2011). Unknown regolith mixtures on Mars-sampling missions could obscure these bands. Here the case is made for determining, via a statistical method, sets of characteristic bands to be used as identifiers, independent of band intensity or number of bands (Rolfe et al., 2016). AA have upwards of 25 potentially identifying bands and this method defines sets of 10–19 bands per AA. Examination of AA-doped Mars-like basalt resulted in a maximum of eight bands being identified, as some characteristic bands were obscured by mineral bands, including the strongest intensity band in some cases. This proved the need for characteristic bands to be defined, enabling successful identification of AA. The ESA ExoMars Rover mission will crush and then pass the sample to the Raman Laser Spectrometer. We crushed a Mars-like basalt to a similar grain size expected to be created by the rover. Our samples were doped with 1 % (by weight) AA samples, resulting in no detection of AA, because of loss of original spatial context and spaces between the grains. We recommend that Raman spectroscopy on future missions should be conducted before the sample is crushed. Halite-entombed halophilic microbes, known to survive being entombed, were exposed to Mars-like surface (including temperature, pressure, atmospheric composition and UV) and freeze-thaw cycle (plus pressure and atmospheric composition) conditions. This test on the survival of the microbes showed that survival rates quickly deteriorated in surface conditions, but freeze-thaw cycle samples had well preserved Raman biosignatures, indicating that similar signatures could be detectable on Mars if similar life persists in evaporitic material or brines today

Studies on Fruit and Yield Traits in Indigenous Coloured Varieties of Mango (Mangifera indica L.) in South Gujarat, India

An investigation on fruit descriptors and yield in twelve mango varieties was conducted under South Gujarat conditions. Maximum fruit length was recorded in cv. Totapuri (16.23cm). Vanraj showed the highest values for fruit width (11.67cm), fruit circumference (37.37cm), fruit weight (729g), fruit volume (575.59cm3) and fruit pulp (78.93%). Maximum TSS (21.20%), acidity (0.42%) and fruit firmness (7.00 rating) was observed in cvs. Deshi-1, Deshi-3 and Makaram, respectively. 'Totapuri' had maximum total shelf-life (21.33 days), number of fruits per tree (383.00) and fruit yield (236.80kg/tree). The varieties had green to yellow ground-colour of peel. All the varieties had red-blush peel colour, excepting cvs. Dadamio, Makaram and Swarnarekha which were purplish-red. Similarly, pulp colour ranged from light yellow to light orange. Based on overall performance, cvs. Alphonso, Deshi-1, Deshi-2, Kesar, Khandesi Borasio, Totapuri and Vanraj proved to be superior to the other varieties

Hot Core, Outflows and Magnetic Fields in W43-MM1 (G30.79 FIR 10)

We present submillimeter spectral line and dust continuum polarization observations of a remarkable hot core and multiple outflows in the high-mass star-forming region W43-MM1 (G30.79 FIR 10), obtained using the Submillimeter Array (SMA). A temperature of $\sim$ 400 K is estimated for the hot-core using CH$_3$CN (J=19-18) lines, with detections of 11 K-ladder components. The high temperature and the mass estimates for the outflows indicate high-mass star-formation. The continuum polarization pattern shows an ordered distribution, and its orientation over the main outflow appears aligned to the outflow. The derived magnetic field indicates slightly super-critical conditions. While the magnetic and outflow energies are comparable, the B-field orientation appears to have changed from parsec scales to $\sim$ 0.1 pc scales during the core/star-formation process.Comment: accepted, ApJ Letter

Reduction of cogging torque of radial flux permanent magnet brushless DC motor by magnet shifting technique

  Introduction. In spite of many advantages of radial flux permanent magnet brushless DC motors it suffers from the distinct disadvantage of high cogging torque. The designer must emphasize to reduce the cogging torque during the design stage. This paper introduces magnet shifting technique to mitigate cogging torque of surface mounted radial flux brushless DC motor. Methodology. Initially 200 W, 1000 rpm surface mounted radial flux permanent magnet brushless DC motor is designed with symmetrical placement of permanent magnets with respect to each other on rotor core. Cogging torque profile of this initial motor is obtained by performing finite element modelling and analysis. Originality. This design has been improved by shifting the position of permanent magnets with respect to adjacent permanent magnets. The effect of magnet shifting on cogging torque has been analyzed by performing finite element analysis. Results. It has been examined that the peak to peak cogging torque is decreased from 1.1 N×m to 0.6 N×m with shifting of permanent magnets respectively.Вступ. Незважаючи на багато переваг безщіткових двигунів постійного струму з радіальним магнітним потоком, вони мають явний недолік, що полягає у високому крутному моменті зубчатої передачі. Проектувальник повинен зосередитись на зниженні крутного моменту зубчатої передачі на етапі проектування. У цій статті представлена методика зсуву магніту для зменшення крутного моменту зубчатої передачі безщіткового двигуна постійного струму з радіальним потоком, встановленого на поверхні. Методологія. Спочатку безщітковий двигун постійного струму з радіальним магнітним потоком потужністю 200 Вт, 1000 об/хв спроектований із симетричним розміщенням постійних магнітів відносно один одного на сердечнику ротора. Розподіл крутного моменту зубчатої передачі цього початкового двигуна отриманий шляхом аналізу методом скінчених елементів (МСЕ). Оригінальність. Ця конструкція була вдосконалена за рахунок зсуву положення постійних магнітів по відношенню до сусідніх постійних магнітів. Вплив зсуву магніту на крутний момент зубчатої передачі було проаналізовано за допомогою аналізу МСЕ. Результати. Досліджено, що піковий крутний  момент зубчатої передачі зменшився з 1,1 Н×м до 0,6 Н×м, відповідно, при зсуві постійних магнітів