A semidefinite relaxation procedure for fault-tolerant observer design

A fault-tolerant observer design methodology is proposed. The aim is to guarantee a minimum level of closed-loop performance under all possible sensor fault combinations while optimizing performance under the nominal, fault-free condition. A novel approach is proposed to tackle the combinatorial nature of the problem, which is computationally intractable even for a moderate number of sensors, by recasting the problem as a robust performance problem, where the uncertainty set is composed of all combinations of a set of binary variables. A procedure based on an elimination lemma and an extension of a semidefinite relaxation procedure for binary variables is then used to derive sufficient conditions (necessary and sufficient in the case of one binary variable) for the solution of the problem which significantly reduces the number of matrix inequalities needed to solve the problem. The procedure is illustrated by considering a fault-tolerant observer switching scheme in which the observer outputs track the actual sensor fault condition. A numerical example from an electric power application is presented to illustrate the effectiveness of the design

New knowledge structures or just common ground?: breakthroughs in international negotiations

Why do breakthroughs in international negotiations happen; and why at a given time? This study evaluates the explanatory power of two theoretical approaches regarding the agreement between Soviet Premier N. Krushchev and US President J. F. Kennedy on the Limited Test Ban Treaty (LTBT) in 1963. How can this agreement best be explained? Was the agreement facilitated by the emergence of new knowledge structures, as the cognitive mapping approach argues? Or is a more nuanced interpretation of the Test Ban negotiations necessary to explain why the LTBT was reached

A Machine-Synesthetic Approach To DDoS Network Attack Detection

In the authors' opinion, anomaly detection systems, or ADS, seem to be the most perspective direction in the subject of attack detection, because these systems can detect, among others, the unknown (zero-day) attacks. To detect anomalies, the authors propose to use machine synesthesia. In this case, machine synesthesia is understood as an interface that allows using image classification algorithms in the problem of detecting network anomalies, making it possible to use non-specialized image detection methods that have recently been widely and actively developed. The proposed approach is that the network traffic data is "projected" into the image. It can be seen from the experimental results that the proposed method for detecting anomalies shows high results in the detection of attacks. On a large sample, the value of the complex efficiency indicator reaches 97%.Comment: 12 pages, 2 figures, 5 tables. Accepted to the Intelligent Systems Conference (IntelliSys) 201

Substituting the main group element in cobalt - iron based Heusler alloys: Co2_2FeAl1−x_{1-x}Six_x

This work reports about electronic structure calculations for the Heusler compound Co$_2$FeAl$_{1-x}$Si$_x$. Particular emphasis was put on the role of the main group element in this compound. The substitution of Al by Si leads to an increase of the number of valence electrons with increasing Si content and may be seen as electron-doping. Self-consistent electronic structure calculations were performed to investigate the consequences of the electron doping for the magnetic properties. The series Co$_2$FeAl$_{1-x}$Si$_x$ is found to exhibit half-metallic ferromagnetism and the magnetic moment follows the Slater-Pauling rule. It is shown that the electron-doping stabilises the gap in the minority states for $x=0.5$.Comment: J. Phys. D (accepted

Effect of Selection Process on Organizational Performance in the Brewery Industry of Southern Nigeria

The aim of this paper is to investigate the “Effect of Selection Process on Organizational Performance in the Brewery Industry of Southern Nigeria”.  Guided by Reflection and Attribution Theory, the research sought to: (i) ascertain the extent to which there was a positive relationship between employment tests and creativity, (ii) determine the extent to which there was a positive relationship between selection interview and profitability. Two hypotheses were formulated to guide the study. Through proportionate stratified random sampling, 328 individuals were selected from the organizations of study.  Responses from the questionnaire were complemented with personal interviews of some selected management staff.  The data obtained were analyzed using frequency tables and the values expressed in percentages. Pearson Product Moment Correlation was used for testing the hypotheses and t-test was used for testing the level of significance of correlation coefficient at 5% error and 3-degrees of freedom.  The findings of this study are: there is a positive relationship between employment tests and creativity; there is a positive relationship between selection interview and profitability. Keywords: Selection process, Organization performance, Employment tests, Selection interview

MARKETING STRATEGY AND ITS EFFECTS ON THE ORGANIZATION (A CASE STUDY OF TOWER ALUMINIUM NIGERIA PLC)

This is a summary of the entire work which seeks to investigate the marketing programme of manufacturers for products they consider successful and see if such programmes approximates to an optimal strategy.  This is because good performance is a function of good planning.  Strategy refers to the course of action towards achieving planned objectives.  Marketing strategies are therefore plans and ways in which goals and objectives of any company can be attained.  In an attempt to see how these variables are manipulated by organizations, the researcher made use of the questionnaire and interview method to gather his primary data for analysis and interpretation.  However, due to the nature of the product, it was discovered that the organization made use of direct marketing as a promotional tool for price stability though depending on the cost of production.  The researcher also found out those sales influenced by the cultural and social values of the people, and that competition in the industry is very keen.  Now, with this in mind, where every organization in the industry is trying to get a major part of the market share, what should Tower Building Products do?  It is recommended by the researcher that training scheme should be introduced; there should be continuous marketing research and that advertising should be given priority. Keywords: Marketing, Strategies, controllable variables, non- controllable variables, Macro and Micro environments

Ambulatory chest physiotherapy in mild-to-moderate acute bronchiolitis in children under two years of age - A randomized control trial

Objective: The aim of this study was to compare the role of a chest physiotherapy (CP) intervention to no intervention on the respiratory status of children under two years of age, with mild-to-moderate bronchiolitis. Methods: Out of 80 eligible children observed in the Emergency Room, 45 children completed the study with 28 randomized to the intervention group and 17 to the control group. The intervention protocol, applied in an ambulatory setting, consisted of combined techniques of passive prolonged slow expiration, rhinopharyngeal clearance and provoked cough. The control group was assessed with no chest physiotherapy intervention. The efficacy of chest physiotherapy was assessed using the Kristjansson Respiratory Score at the admission and discharge of the visit to the Emergency Room and during clinical visits at day 7 and day 15. Results: There was a significant improvement in the Kristjansson Respiratory Score in the intervention group compared to the control group at day 15 [1.2 (1.5) versus 0.3 (0.5); p -value =0.005 , in the control and intervention groups, respectively], with a mean difference (95% CI) of −0.9 ( −1.6 to −0.3 ). Conclusion: Chest physiotherapy had a positive impact on the respiratory status of children with mild-to-moderate bronchiolitis. Clinical trial registration: https://clinicaltrials.gov/ct2/show/NCT04260919

Comets, historical records and vedic literature

A verse in book I of Rigveda mentions a cosmic tree with rope-like aerial roots held up in the sky. Such an imagery might have ensued from the appearance of a comet having `tree stem' like tail, with branched out portions resembling aerial roots. Interestingly enough, a comet referred to as `heavenly tree' was seen in 162 BC, as reported by old Chinese records. Because of weak surface gravity, cometary appendages may possibly assume strange shapes depending on factors like rotation, structure and composition of the comet as well as solar wind pattern. Varahamihira and Ballala Sena listed several comets having strange forms as reported originally by ancient seers such as Parashara, Vriddha Garga, Narada and Garga. Mahabharata speaks of a mortal king Nahusha who ruled the heavens when Indra, king of gods, went into hiding. Nahusha became luminous and egoistic after absorbing radiance from gods and seers. When he kicked Agastya (southern star Canopus), the latter cursed him to become a serpent and fall from the sky. We posit arguments to surmise that this Mahabharata lore is a mythical recounting of a cometary event wherein a comet crossed Ursa Major, moved southwards with an elongated tail in the direction of Canopus and eventually went out of sight. In order to check whether such a conjecture is feasible, a preliminary list of comets (that could have or did come close to Canopus) drawn from various historical records is presented and discussed.Comment: This work was presented in the International Conference on Oriental Astronomy held at IISER, Pune (India) during November, 201

Two distinct sequences of blue straggler stars in the globular cluster M30

Stars in globular clusters are generally believed to have all formed at the same time, early in the Galaxy's history. 'Blue stragglers' are stars massive enough that they should have evolved into white dwarfs long ago. Two possible mechanisms have been proposed for their formation: mass transfer between binary companions and stellar mergers resulting from direct collisions between two stars. Recently, the binary explanation was claimed to be dominant. Here we report that there are two distinct parallel sequences of blue stragglers in M30. This globular cluster is thought to have undergone 'core collapse', during which both the collision rate and the mass transfer activity in binary systems would have been enhanced. We suggest that the two observed sequences arise from the cluster core collapse, with the bluer population arising from direct stellar collisions and the redder one arising from the evolution of close binaries that are probably still experiencing an active phase of mass transfer.Comment: Published on the 24th December 2009 issue of Natur