Metallurgy of armour exhibited at the Palace Armoury, Valletta, Malta

The metallurgy of ten armour pieces from the Palace Armoury Collection in Malta was examined. Results showed that out of ten artefacts examined, six were produced in low carbon steel, one from a high carbon steel and three were made from wrought iron. One of the wrought iron armour pieces was fabricated from a phosphoric iron, an unusual material for these artefacts. All the steel artefacts exhibited a ferrite-pearlite microstructure. In their manufacture, no attempts had been made at producing martensite by full or slack quenching. All metal fragments contained slag inclusions. The elongated nature of the latter suggested that these artefacts were forged into shape.peer-reviewe

Enhancement of Entrepreneurial Leadership: A Case Focusing on a Model of Successful Conflict Management Skills

The purpose of this paper is to present a case study focusing on a new technology start-up firm, founded by two graduate students, an engineer and a business major, who met during their university studies. The case is timely, in that only ten percent of new product introductions result in a profitable business. The causes of failure are numerous and include the following: the market may create failure; inadequate funding and capitalization; and competition from established enterprises. Several research studies also point to rising indications of interfunctional conflict in high technology companies. One reason may be that, today, management teams in such companies are typically comprised of greater levels of diversity in age, gender, ethnicity, education, and life experiences, all of which exacerbate conflicts. New venture teams, especially in a technology start-up, may be united because of the product innovation, but they may easily become disconnected and unrealistic when it comes to the management of the enterprise. The presentation and analysis of a conflict management process herein indicates that the way a start-up team manages its conflicts may have a permanent affect on the success of its entrepreneurial venture. Conflict management does not imply terminating conflict, but involves understanding strategies to minimize dysfunction and enhancing constructive effectiveness as a result of conflict. This case exposed the problems that arise due to the differences in the founders’ education, background, experience and understanding of the necessary entrepreneurial mindset for success. By using a model of conflict management that encompasses four negotiation skill sets, including assessment, intervention, resolution and maintenance, their conflicts were resolved quickly and their partnership re-engineered, increasing the chance of their firm’s long-term success

Combinatorial Hopf Algebras of Simplicial Complexes

International audienceWe consider a Hopf algebra of simplicial complexes and provide a cancellation-free formula for its antipode. We then obtain a family of combinatorial Hopf algebras by defining a family of characters on this Hopf algebra. The characters of these Hopf algebras give rise to symmetric functions that encode information about colorings of simplicial complexes and their $f$-vectors. We also use characters to give a generalization of Stanley’s $(-1)$-color theorem.Nous considérons une algèbre de Hopf de complexes simpliciaux et fournissons une formule sans multiplicité pour son antipode. On obtient ensuite une famille d'algèbres de Hopf combinatoires en définissant une famille de caractères sur cette algèbre de Hopf. Les caractères de ces algèbres de Hopf donnent lieu à des fonctions symétriques qui encode de l’information sur les coloriages du complexe simplicial ainsi que son vecteur-$f$. Nousallons également utiliser des caractères pour donner une généralisation du théorème $(-1)$ de Stanley

Management Systems That Increase Uniformity of the Forage Supply for Year-round Grazing by Spring Calving Herds

A comparison was made between two different systems: a year-round grazing system and a minimal-land grazing system at the McNay Research Farm, Chariton IA. The winter component of a year-round grazing system used sequential grazing of corn crop residues and stockpiled grass legume forages. The winter component of a minimal land system consisted of cows maintaining in drylot. Following grain harvest, four 7.5-acre fields containing corn crop residues were stocked with cows at midgestation at an allowance of 1.5 acres per cow. After 2 months, cows in the year-round grazing system grazed stockpiled tall fescue-red clover or smooth bromegrass-red clover forage at 3 acres/cow for approximately 4 months. Forage organic yields at the initiation of grazing were 3,467 lb./acre for three years on corn crop reside fields and 2,473 and 1,968 for stockpiled tall fescue-red clover and smooth bromegrass-red clover fields. In all years, no seasonal differences in body weight or body condition scores were observed between cows sequentially grazing corn crop residues and stockpiled forage or cows maintained in drylot during winter. Grazing cows consumed less hay resulting in a 3-year average hay excess of 4,235 and 4,743 pounds of hay dry matter per cow in the yearround grazing systems while the minimal land system was deficient in hay by 4,529 pounds of hay dry mater per cow. The summer component of a year-round grazing system involved rotational stocking of smooth bromegrassorchardgrass- birdsfoot trefoil pastures with cow-calf pairs and stocker yearlings at .75 animal units/acre for 40 days, and hay harvest and grazing of tall fescue-red clover and smooth bromegrass-red clover pastures at .33 cow-calf pairs/acre for 57 days and 83 days grazing of smooth bromegrass-orchardgrass-birdsfoot trefoil pastures at .5 cow-calf units per are. The minimal land system involved the rotational stocking of smooth bromegrass-orchardgrass-birdsfoot trefoil pastures with cow-calf pairs grazing at .64 animal units/acre and hay removal from 40% of the pasture. Grazing system did not affect cow body weight, condition score, or calf daily gain in any of the three years. Growing animal production was affected by grazing system; the minimal land system 3-year average was 181 lb./acre compared with year-round system averages of 128.7 and 123.9 lb./acre. The year-round grazing systems also produced more net winter forage than did the minimal land system. Differences in forage quality were only observed between tall fescue-red clover, smooth bromegrass-red clover and smooth bromegrassorchardgrass- birdsfoot trefoil pastures during summer

Capturing entertainment through heart rate dynamics in the playware playground

This paper introduces a statistical approach for capturing entertainment in real-time through physiological signals within interactive playgrounds inspired by computer games. For this purpose children’s heart rate (HR) signals and judgement on entertainment are obtained from experiments on the innovative Playware playground. A comprehensive statistical analysis shows that children’s notion of entertainment correlates highly with their average HR during the game.peer-reviewe

Preliminary studies for capturing entertainment through physiology in physical play

This report presents preliminary physical control experiments for capturing and modeling the affective state of entertainment — that is, whether people are having "fun" — of users of the innovative Play-ware playground, an interactive physical playground. The goal is to con-struct, using representative statistics computed from children's physio-logical hear rate (HR) signals, an estimator of the degree to which games provided by the playground engage the players. For this purpose chil-dren's HR signals, and their expressed preferences of how much "fun" particular game variants are, are obtained from experiments using games implemented on the Playware playground. Neuro-evolution techniques combined with feature set selection methods permit the construction of user models that predict reported entertainment preferences given HR features. These models are expressed as artificial neural networks and are demonstrated and evaluated on two Playware games and the pre-liminary control task requiring physical activity. Results demonstrate that the proposed preliminary control experiment is not an appropriate control for physical activity effects since it may generate HR dynamics rather easy to separate from game-play HR dynamics, and allows one to distinguish entertaining game-play from exercise purely on the artificial basis of the kind of physical activity taking place. Conclusions derived from this study constitute the basis for the design of more appropriate control experiments and user models in future studies.peer-reviewe

Don't classify ratings of affect ; rank them!

How should affect be appropriately annotated and how should machine learning best be employed to map manifestations of affect to affect annotations? What is the use of ratings of affect for the study of affective computing and how should we treat them? These are the key questions this paper attempts to address by investigating the impact of dissimilar representations of annotated affect on the efficacy of affect modelling. In particular, we compare several different binary-class and pairwise preference representations for automatically learning from ratings of affect. The representations are compared and tested on three datasets: one synthetic dataset (testing “in vitro”) and two affective datasets (testing “in vivo”). The synthetic dataset couples a number of attributes with generated rating values. The two affective datasets contain physiological and contextual user attributes, and speech attributes, respectively; these attributes are coupled with ratings of various affective and cognitive states. The main results of the paper suggest that ratings (when used) should be naturally transformed to ordinal (ranked) representations for obtaining more reliable and generalisable models of affect. The findings of this paper have a direct impact on affect annotation and modelling research but, most importantly, challenge the traditional state-of-practice in affective computing and psychometrics at large.peer-reviewe

Multi-Stability and Pattern-Selection in Oscillatory Networks with Fast Inhibition and Electrical Synapses

A model or hybrid network consisting of oscillatory cells interconnected by inhibitory and electrical synapses may express different stable activity patterns without any change of network topology or parameters, and switching between the patterns can be induced by specific transient signals. However, little is known of properties of such signals. In the present study, we employ numerical simulations of neural networks of different size composed of relaxation oscillators, to investigate switching between in-phase (IP) and anti-phase (AP) activity patterns. We show that the time windows of susceptibility to switching between the patterns are similar in 2-, 4- and 6-cell fully-connected networks. Moreover, in a network (N = 4, 6) expressing a given AP pattern, a stimulus with a given profile consisting of depolarizing and hyperpolarizing signals sent to different subpopulations of cells can evoke switching to another AP pattern. Interestingly, the resulting pattern encodes the profile of the switching stimulus. These results can be extended to different network architectures. Indeed, relaxation oscillators are not only models of cellular pacemakers, bursting or spiking, but are also analogous to firing-rate models of neural activity. We show that rules of switching similar to those found for relaxation oscillators apply to oscillating circuits of excitatory cells interconnected by electrical synapses and cross-inhibition. Our results suggest that incoming information, arriving in a proper time window, may be stored in an oscillatory network in the form of a specific spatio-temporal activity pattern which is expressed until new pertinent information arrives

An evolutionary approach for interactive computer games

The authors would like to thank Jeong Keun Park for his valuable contribution to the graphical representation of the Dead End game.In this paper we introduce the first stage of experiments on neuro-evolution mechanisms applied to predator/prey multi-character computer games. Our test-bed is a computer game where the prey (i.e. player) has to avoid its predators by escaping through an exit without getting killed. By viewing the game from the predators’ (i.e. opponents’) perspective, we attempt off-line to evolve neural-controlled opponents capable of playing effectively against computer-guided fixed strategy players. Their efficiency is based on cooperation which emerges from an abstract type of partial interaction with their environment. In addition, investigation of behavior generalization demonstrated the crucial contribution of playing strategies in the development of successful predator behaviors. However, emergent well-behaved opponents trained off-line with fixed strategies do not make the game interesting to play. We therefore present an evolutionary mechanism for opponents that keep learning from a player while playing against it (i.e. on-line) and we demonstrate its efficiency and robustness in increasing the predators’ performance while altering their behavior as long as the game is played. Computer game opponents following this on-line learning approach show high adaptability to changing player strategies, which provides evidence for the approach’s effectiveness and interest against human players.peer-reviewe