Search

Contact Logics provide a natural framework for representing and reasoning about regions in several areas of computer science. In this paper, we focus our attention on reasoning methods for Contact Logics and address the satisfiability problem and the unifiability problem. Firstly, we give sound and complete tableaux-based decision procedures in Contact Logics and we obtain new results about the decidability/complexity of the satisfiability problem in these logics. Secondly, we address the computability of the unifiability problem in Contact Logics and we obtain new results about the unification type of the unifiability problem in these logics.

The interest in multivariate statistical process control (MSPC) has increased as the industrial processes have become more complex. This paper presents an industrial process involving a plastic part in which, due to the number of correlated variables, the inversion of the covariance matrix becomes impossible, and the classical MSPC cannot be used to identify physical aspects that explain the causes of variation or to increase the knowledge about the process behaviour. In order to solve this problem, a Multivariate Statistical Process Control based on Principal Component Analysis (MSPC-PCA) approach was used and an R code was developed to implement it according some commercial software used for this purpose, namely the ProMV (c) 2016 from ProSensus, Inc. (www.prosensus.ca). Based on used dataset, it was possible to illustrate the principles of MSPC-PCA. This work intends to illustrate the implementation of MSPC-PCA in R step by step, to help the user community of R to be able to perform it., FCT - Fundação para a Ciência e a Tecnologia(UID/CEC/00319/2013)

This paper studies the dynamic time-varying formation control of multi-agent systems. Aiming at the unmanned vehicle systems, based on the static time-varying formation in literature [18], a multi-agent dynamic time-varying formation control based on consistency is put forward. Additionally, the sufficient conditions for the agreement and the steps for solving the control parameters are given. The simulation is conducted to prove the effectiveness and robustness of the theoretical results.

Software frameworks are difficult for plugin developers to use, even when they are well designed and documented. Some of these difficulties stem from the many constraints that frameworks impose on plugin code. These constraints might restrict operations from being called on certain objects, or they might restrict how long an object is available. Additionally, the constraints are relative to the current context of the plugin, and they can involve multiple, interacting framework objects. This paper proposes a lightweight specification system and analysis to check plugins from a semantic perspective, rather than a purely structural view.

This paper proposes a novel approach to design a controller in discrete time for the class of uncertain nonlinear systems in the presence of magnitude constrains of control signal which are treated as the saturation nonlinearity. A associative law between reinforcement learning algorithm based on adaptive NRBF neural networks and the theory of robust control Ho is set up in a novel control structure, in which the proposed controller allows learning and control on-line to compensate multiple uncertain nonlinearities as well as minimizing both the H. tracking performance index function and the unknown nonlinear dynamic approximation errors. The novel theorem of robust stabilization of the closed-loop system is declared and proved. Simulation results verify the theoretical analysis.

From the point of view of a data warehouse system, collecting and receiving information from source systems is crucial for all subsequent business intelligence applications. Incoming information can generally be classified into two types: (1) the state-oriented data and (2) event-oriented data or transactional data, which contains information about the change performed by processes on the instances of information objects. On the way towards achieving the goal of a full-fledged active data warehouse it becomes more and more important to provide data with minimal latency. In this paper we focus on dimensional data which is provided by general data warehouse applications. The information transfer is performed via messages containing the change of information on the dimension instances. The proposed approach is able to validate the event-messages, reconstruct the complete history of the dimension and provide a well applicable ''comprehensive slowly changing dimension'' (cSCD) interface for queries on the historical and current state of the dimension. A description of the prototype implementation for this kind of an ''active integration'' in a data warehouse and a case study at T-Mobile conclude the paper.

The luminosity upgrade of the Large Hadron Collider (LHC) at CERN requires the installation of additional collimators in the dispersion suppressor regions of the accelerator. The upgrade foresees the installation of one additional collimator on either side of interaction point 7 (IP7) at the location of the existing main dipoles (MBs) that will be replaced by shorter and more powerful dipoles, and of one additional collimator on either side of IP2 at the location of existing empty cryostats. This paper describes the design and the construction status of the full-length prototype of the 11-T dipole magnet, which is needed for IP7. This magnet features a two-in-one structure, like the LHC MB, impregnated coils made of Nb3Sn conductor, an inner bore of 60 mm, and a magnetic length of about 5.3 m. Two 11-T magnets are needed to replace a 15-m long MB. A by-pass cryostat placed in between the two magnets allows creating a room temperature space for the additional collimators. The magnet is designed to provide the same integrated field as the MB at nominal field. However, due to the difference in transfer function at lower field, a correction by means of a trim current has been considered. A full-length prototype is currently under construction at CERN with the goal of developing the manufacturing and inspection procedures prior to launch the series production. For this, new tooling has been developed and optimized during the fabrication of fully representative practice coils. This paper describes the design of the magnet, the main manufacturing steps, and corresponding quality indicators, which will be used to monitor the series production. Finally, the production and installation schedule will be presented.

In this paper, solutions for precise maneuvering of an autonomous small (e.g., 350-class) Unmanned Aerial Vehicles (UAVs) are designed and implemented from smart modifications of non expensive mass market technologies. The considered class of vehicles suffers from light load, and, therefore, only a limited amount of sensors and computing devices can be installed on-board. Then, to make the prototype capable of moving autonomously along a fixed trajectory, a &ldquo, cyber-pilot&rdquo, able on demand to replace the human operator, has been implemented on an embedded control board. This cyber-pilot overrides the commands thanks to a custom hardware signal mixer. The drone is able to localize itself in the environment without ground assistance by using a camera possibly mounted on a 3 Degrees Of Freedom (DOF) gimbal suspension. A computer vision system elaborates the video stream pointing out land markers with known absolute position and orientation. This information is fused with accelerations from a 6-DOF Inertial Measurement Unit (IMU) to generate a &ldquo, virtual sensor&rdquo, which provides refined estimates of the pose, the absolute position, the speed and the angular velocities of the drone. Due to the importance of this sensor, several fusion strategies have been investigated. The resulting data are, finally, fed to a control algorithm featuring a number of uncoupled digital PID controllers which work to bring to zero the displacement from the desired trajectory.

Focal boost to dominant intraprostatic lesions (DILs) has recently been proposed for prostate radiation therapy. Accurate and fast delineation of the prostate and DILs is thus required during treatment planning. In this paper, we develop a learning-based method using positron emission tomography (PET)/computed tomography (CT) images to automatically segment the prostate and its DILs. To enable end-to-end segmentation, a deep learning-based method, called cascaded regional-Net, is utilized. The first network, referred to as dual attention network, is used to segment the prostate via extracting comprehensive features from both PET and CT images. A second network, referred to as mask scoring regional convolutional neural network (MSR-CNN), is used to segment the DILs from the PET and CT within the prostate region. Scoring strategy is used to diminish the misclassification of the DILs. For DIL segmentation, the proposed cascaded regional-Net uses two steps to remove normal tissue regions, with the first step cropping images based on prostate segmentation and the second step using MSR-CNN to further locate the DILs. The binary masks of DILs and prostates of testing patients are generated on the PET/CT images by the trained model. For evaluation, we retrospectively investigated 49 prostate cancer patients with PET/CT images acquired. The prostate and DILs of each patient were contoured by radiation oncologists and set as the ground truths and targets. We used five-fold cross-validation and a hold-out test to train and evaluate our method. The mean surface distance and DSC values were 0.666 ± 0.696 mm and 0.932 ± 0.059 for the prostate and 0.814 ± 1.002 mm and 0.801 ± 0.178 for the DILs among all 49 patients. The proposed method has shown promise for facilitating prostate and DIL delineation for DIL focal boost prostate radiation therapy.

For a purpose of improvement of project management, we should determine the success right or wrong of project objectively and quantitatively. On the other hand, a decision of success right or wrong of software development projects has been evaluated subjectively by a questionnaire for stakeholders concerned. Furthermore, the study of definition of project success right or wrong and quantitative decision techniques is not found. Recently, gathering of the attribute data about software development projects in Japan has been performed by the IPA/SEC (Software Engineering Centre of the Information-Technology Promotion Agency Japan). Therefore, we developed the diagnostic technique to judge the success right or wrong on a project by a discriminant analysis based on the actual data of IPA/SECs in the precedent study. Also, we tried to develop the diagnostic technique of success right or wrong of project based on the “Success degree estimation mode” in this study. In this paper, we would like to propose the result of comparison between the effectiveness of these diagnostic techniques of the project.

In my former Paper, I have given the changes which have happened in the situation of six double stars. When the causes of these observed changes in the double star Castor were investigated, I had recourse to the most authentic observations I could find, of the motions in right-ascension and polar distance of this star. But the Tables which have been lately published, in the last volume of the observations made by the Astronomer Royal at Greenwich, give us now the proper motions of 36 principal stars, of which α Geminorum is one; and, as the motion of this star, especially in north polar distance, is very different from what it has been supposed in my former examination, it will be necessary to review the arguments which have been used, in order to ascertain what will be the result of this new motion. We shall here again follow the order of the paragraphs of the former Paper, and denote those which treat of the same motions, with the same letters, that they may be readily compared.

The attention of physiologists has been very much with­ drawn, for the last half century, from the consideration of the different states of the circulating and secreted fluids, in conse­quence of the opinion that the nervous and fibrous or mus­cular systems can afford satisfactory interpretations of the phenomena of living beings; and on account of the disgust produced by the visionary properties and groundless hypo­theses, originating in the humoural doctrines of Galen. But late experiments have manifested, that various things taken into the stomach can be made at pleasure to produce consider­able effects, by impregnating sensibly the blood and urine, as well as the milk, sweat, and perhaps saliva. Further; the fine experiments of Professor Colman have shewn, that the conta­gious glanders may be excited in the ass by the transfusion of the blood of a glandered horse, and the matter from the nose of the glandered ass can produce this disease in the horse or the ass. Hence I apprehend it is reasonable to expect, that the farther investigation of the properties of the animal fluids will afford gratifying instruction to the Researcher in natural science, and important practical information to the Physician. On the present occasion, I desire the honour of communi­cating the knowledge I may have acquired, by investigating the properties of expectorated matter secreted by the bron­chial membrane. The appearances of this substance serve to regulate the judgment of the Physician concerning several dis­eases of the lungs; but especially of that of pulmonary tubercles which yearly destroys 120,000 to 140,000 subjects of the United Kingdom. It is fit that I remark, that I do not notice in this paper the ingenious experiments of several learned Chemists, because by so doing I should be led into a detail of too great extent for my design.

In this Paper I shall offer to the Society a continuation of those researches, the details of which have been already honoured with a place in their Transactions; and I trust, that the experiments and observations which I have to communicate, will be found to elucidate some important but obscure parts of chemical philosophy. In the last Paper, which I had the honour of presenting to this Body, I have given an account of a number of experiments made with a view of decomposing the fluoric acid: the most probable inference, from my results, was that the pure liquid fluoric acid consists of hydrogen united to a substance, which, from its strong powers of combination, has not as yet been procured in a separate form, but which is detached from hydrogen by metals, and which, in union with the basis of the boracic acid and silica, forms the fluo-boric and silica ted fluoric gases.

The observations of the satellites of the Georgian planet, of which an account is given in this paper, are of such a nature that, in order to judge of them properly, and to make them useful to those who would continue them, it will be necessary to enter into some particulars relating to the telescopic powers required for critically viewing such difficult objects. The great distance of the Georgian planet renders an attempt to investigate the movements of its satellites a very arduous undertaking; for their light, having to traverse a space of such vast extent before it can reach us, is so enfeebled, and their apparent diameter so diminished, that an instrument, to be prepared for viewing them, must be armed with the double power of magnifying and of penetrating into space.

Wikipedia categories, a classification scheme built for organizing and describing Wikpedia articles, are being applied in computer science research. This paper adopts a systematic literature review approach, in order to identify different approaches and uses of Wikipedia categories in information retrieval research. Several types of work are identified, depending on the intrinsic study of the categories structure, or its use as a tool for the processing and analysis of other documentary corpus different to Wikipedia. Information retrieval is identified as one of the major areas of use, in particular its application in the refinement and improvement of search expressions, and the construction of textual corpus. However, the set of available works shows that in many cases research approaches applied and results obtained can be integrated into a comprehensive and inclusive concept of information retrieval.

PID controller is widely used in many fields. The input sequence and output sequence of a well-parameterized PID controller are transformed into a matrix presented in images in this paper, and a Every-Time step data augmentation algorithm is operated. This paper propose a image to image Convolutional Neural Networks(CNN) structure to learn the PID controller, which incorporates the successful methods in computer vision and deep learning to control field. The simulation is performed using Matlab/Simulink and Keras[1]. The simulation demonstrates that the CNN controller is capable in performance.

Subject of research. The paper presents a semi-automatic method of speaker identification based on prosodic features comparison - statistics of phone lengths. Due to the development of speech technologies in recent times, there is an increased interest in searching of expert methods for speaker's voice identification, which supplement existing methods to increase identification reliability and also have low labour intensity. An efficient solution for this problem is necessary for making the reliable decision whether the voices of the speakers in the audio recordings are identical or different. Method description. We present a novel algorithm for calculating the difference of speakers’ voices based on comparing of statistics for phone and allophone lengths. Characteristic feature of the proposed method is the possibility of its application along with the other semi-automatic methods (acoustic, auditive and linguistic) due to the lack of a strong correlation between analyzed features. The advantage of the method is the possibility to carry out rapid analysis of long-duration recordings because of preprocessing automation for data being analyzed. We describe the operation principles of an automatic speech segmentation module used for statistics calculation of sound lengths by acoustic-phonetic labeling. The software has been developed as an instrument of speech data preprocessing for expert analysis. Method approbation. This method was approved on the speech database of 130 speech records, including the Russian speech of the male speakers and female speakers, and showed reliability equal to 71.7% on the database containing female speech records, and 78.4% on the database containing male speech records. Also it was experimentally established that the most informative of all used features are statistics of phone lengths of vowels and sonorant sounds. Practical relevance. Experimental results have shown applicability of the proposed method for the speaker recognition task in the course of phonoscopic examination.

In the design and production of underwater acoustic transducers, two problems may arise. First, how does the design engineer specify the transducer component properties and their tolerances to best produce a cost effective transducer? Second, how does the production engineer determine if received transducer components will produce the desired quantity of acceptable transducers? The importance of these problems increases rapidly as the volume and production rate increase. This paper presents a Monte Carlo simulation capable of predicting the statistical variability of transducer characteristics from component variability data. The simulation consists of a power residue method of random number generation, a two‐tailed chi‐square test to insure that the numbers are random, a procedure which divides the probability density function of a component's property into equal area sections (equal chance for selection of property value) and a mathematical representation of the transducer. The simulation randomly choos...

Video synopsis provides a means for fast browsing of activities in video. Principal background selection (PBS) is an important step in video synopsis. Existing methods make PBS in an offline way and at a high memory cost. In this paper we propose a novel background selection method, ``online principal background selection'' (OPBS). The OPBS selects n principal backgrounds from N backgrounds in an online fashion with a low memory cost, making it possible to build an efficient online video synopsis system. Another advantage is that, with OPBS, the selected backgrounds are related to not only background changes over time but also video activities. Experimental results demonstrate the advantages of the proposed OPBS.

The copious contents of this lecture relate chiefly to the power possessed by the eye to accommodate itself to the perception of objects at different distances, concerning which a variety of opinions have been entertained. After some general considerations on the sense of vision, from which it appears that though the extent of the field of perfect vision for each position of the eye be not very great, yet there is reason to believe that its refractive powers are calculated to take in a moderately distinct view of a whole hemisphere : the author, aware how essential it is in an inquiry of so delicate a nature to proceed upon solid, and as far as possible incontrovertible grounds, delivers a set of dioptrical propositions (eight in number), each accompanied by some scholia and corollaries, from which he means to deduce the principal inferences brought forward in the sequel of the lecture.

The object of the author is to determine how the greatest effect may be produced by the voltaic battery, with the least waste of power and expense. For this purpose he had one battery constructed of twenty pairs of plates of zinc and copper of large dimensions, each plate being four feet long and two feet wide. Each pair was connected together only at the top by a strap of lead, so that both sides of each plate were exposed to the action of the fluid in the trough. The trough was made entirely of wood, with wooden partitions, made water-tight by cement; and this battery when in action was charged with a mixture of three parts nitrous acid, with one of sulphuric diluted with three parts of water.

The attempts that have been made by some chemists to represent the attractive forces of chemical bodies by number, having been limited and hastily abandoned, some important consequences which follow, from the principle of numerical representation, have been entirely overlooked. Although there may be circumstances that will occasion exceptions to general rules, it appears that 100 numbers may be made correctly to represent nearly all the phenomena of the mutual action of 100 different salts, which, if described separately, would require about 5000 separate articles.

The use of the common beam-compass for dividing having been justly objected to, on account of the danger of bruising the divisions which have been made, by replacing the points of the compass into them, the author proposes a means of obviating that inconvenience, by substituting a microscope instead of one of the points; and he describes a method of proceeding, in which there is no need ever to set the other point into any division already made. The beam to be employed for this purpose must have a fixed point at one extremity, and at the other a centre of motion, round which the length of the beam may revolve as radius. A microscope is to slide in a groove along the middle to any required distance from the point; and in order that these may both be over the circle at the same time, the centre of motion must be capable of adjustment, that it may be fixed at a greater or less distance from the centre of the circle, according to the magnitude of the arc intercepted between the point and microscope.

The Supplement now offered to the Society, is intended to clear up certain points which have been represented to the author as obscure or doubtful in his former communications, and at the same time to connect more intimately the prismatic experiments of the second paper with those made upon convex glasses, and described in the author’s first paper on the subject. Since Dr. Herschel has heard the originality of his observation of the red bow called in question, upon the ground that a red bow had been observed by Sir Isaac Newton, which is merely the converse of the blue bow (the change of colour being dependent upon the direction in which the light is received upon the prism), Dr. Herschel first endeavours to answer the objection, and reminds us that in his former observations the angular breadth and elevation of the two bows are different; but those of the Newtonian blue and red bows are said to be, and are, necessarily equal. In the Newtonian experiment also, the same beam of light is made to exhibit both phenomena, being received upon two right-angled prisms, applied base to base, so that one portion of the light is reflected upwards, as a blue bow from the under surface of the first prism; and the remainder, by transmission, through the second prism, appears as a red bow to an eye beneath. But in Dr. Herschel’s experiment, the same prism is made to exhibit, to an eye in the same situation, the red bow as well as the blue, by means of light transmitted in an opposite direction through the under surface of the prism, without any occasion for a second prism, which (as Dr. Herschel observes) is necessary in the Newtonian method of conducting the experiment.

Although the author is most ready to admit the accuracy of Mr. Troughton’s method of dividing, which was described in our Transactions for the year 1809, and by which the mural circle at Greenwich has been divided, it appeared to him that some improvement might be made in regard to simplicity and facility of execution. The general principle of the method here described by Capt. Kater is, in fact, the same as that of the beam compass; but his apparatus, instead of having points like the beam compass, has two micrometer microscopes adjustable to different distances, as aliquot parts of an arc or line to be divided. For the purpose of marking on the surface of the instrument any assumed interval between the microscopes, certain thin pieces of small brass, carrying dots, are employed, with a clamp for fixing them to any part of the limb, and with proper screws for adjusting them to any precise position.

Since in the examination of objects so minute and so distant as these satellites, it is necessary not only to magnify for the purpose of removing them from the body of the planet itself, but also to collect as much of their light as may be, in order to render the impression they make on the eye sensible, no instrument less than a 20-feet te­lescope is sufficient for discerning them; and even with an instrument of this description it is but with a favourable atmosphere, and through a small part of their orbit round the primary, that Dr. Herschel has been able to make his observations; and he has also occasionally availed himself of the greater light that is to be obtained by concave eye-glasses, notwithstanding the smallness of the field of view, and other objections to their use. The magnifying powers employed on these occasions have been from 300 to 800 times; sometimes one, and sometimes another being used, according to the states of the air or moon, or other circumstances. The observations here recorded, were made principally from the year 1787 to 1798 inclusive, and they are given in the order in which they occurred with all the phenomena noticed each time, and notes of correction added from subsequent observations respecting stars mistaken for satellites, or satellites wrongly numbered. For Dr. Herschel always added a configuration to his descriptions,in order to avoid mistakes, and in general made, by previous estimate, a sketch of the places where known satellites might be expected; some misconcep­tions were unavoidable, in consequence of the interruptions to his observations from cloudy or moon-light nights, as well as from small stars that unexpectedly interfered.

The process which the author endeavours to establish in this essay, being the leading theorem in the calculus of derivations, presented under a new aspect, may, he says, be regarded as an universal instrument of calculations, extending to the composition as well as analysis of functions of every kind, but it promises to be especially useful in the numerical solution of equations. Mr. Horner then proceeds to the illustration of his method, and to explain the investigations to which it is applicable, by details which do not admit of explanation.

Mr. Gompertz begins by establishing a system of notation intended to avoid unnecessary repetitions and circumlocution, and proceeds to apply his abbreviated expressions to a more accurate determination of the value of a number of joint lives, according to any given tables of mortality, than can be obtained by the common approximations.

The Commissioners of Weights and Measures having recommended, for the legal determination of the standard yard, that employed by General Roy in the measurement of a base on Hounslow Heath, as a foundation for the trigonometrical operations that have been carried on by the Ordnance throughout the country, it became necessary to examine the standard to which the report alludes, with the intention of subsequently deriving from it a scale of feet and inches. This standard consists of an iron bar, 20 feet long, described by Captain Kater, in which gold points are inserted, at the distance of 40 inches from each other, from a standard scale of Mr. Ramsden’s, which was declared similar to that of General Roy, and also to that of the Royal Society; but on examining these scales, Captain Kater ascertained the existence of material differences between them; and being aware of the existence of other standards of high authority, he procured and compared them.

To those mathematicians who have investigated the theory of the refracting telescope, it has often, says Mr. Herschel, been objected, that little practical benefit has resulted from their speculations. Although the simplest considerations suffice for correcting that part of the aberration which arises from the different refrangibility of the different coloured rays, yet in the more difficult part of the theory of optical instruments which relates to the correction of the spherical aberration, the necessity of algebraic investigation has always been , acknowledged; although, however, the subject is confessedly within its reach, a variety of causes have interfered with its successful prosecution, and the best artists are content to work their glasses by empirical rules. In the investigations detailed in this paper, the author’s object is, first to present, under a general and uniform analysis, the whole theory of the aberration of spherical surfaces; and then to furnish practical results of easy computation to the artist, and applicable, by the simplest interpolations, to the ordinary materials on which he works. In pursuing these ends he has found it necessary somewhat to alter the usual language employed by optical writers;—thus, instead of speaking of the focal length of lenses, or the radii of their surfaces , he speaks of their powers and curvatures ; designating, by the former expression, the quotient of unity by the number of parts of any scale which the focal length is equal to; and by the latter, the quotient similarly derived from the radius in question. After adverting to some other parts of the subject of this paper, more especially to the problem of the destruction of the spherical aberration in a double or multiple lens, and to the difficulties which it involves, Mr. Herschel observes, that one condition, hitherto unaccountably overlooked, is forced upon our attention by the nature of the formulæ of aberration given in this paper; namely, its destruction not only from parallel rays, but also from rays diverging from a point at any finite distance, and which is required in a perfect telescope for land objects, and is of considerable advantage in those for astronomical use: 1st, The very moderate curvatures required for the surfaces; 2nd, That in this construction the curvatures of the two exterior surfaces of the compound lens of given focal length vary within very narrow limits, by any variation in either the refractive or dispersive powers at all likely to occur in practice; 3rd, That the two interior surfaces always approach so nearly to coincidence, that no considerable practical error can arise from neglecting their difference, and figuring them on tools of equal radii.

The centering of a triple achromatic object-glass has always presented considerable difficulties to practical opticians, which Dr. Wollaston has succeeded in removing, with regard to an excellent telescope in his own possession, by observing the relative position of the fifteen small images of aluminous object near the eye-glass, which are formed by the binary combinations of the reflexions of the six surfaces concerned, and which are seen by an eye situated beyond the object-glass, and assisted, if required, by a lens. When these images are all in the same right line, it is obvious that the glasses are not only well adjusted together, but that each is well centered; and by means of four screws acting on each glass, Dr. Wollaston was able to make the adjustment so complete, as considerably to improve the powers of the instrument.

The specimens described in this paper were taken in the month of June, in a lake three miles from Mexico, at an elevation of 8000 feet above the level of the sea. The usual temperature of the lake is 60°, and they are in such abundance as to form a principal article of food of the peasantry. By the assistance of annexed drawings by Mr. Bauer, Sir Everard fully describes the male and female organs of these animals, and is enabled to decide that they are a full grown and perfect tribe. “The attack therefore,” says the author, “made upon Mr. John Hunter’s sagacity by Mr. Rusconi, in his work surles Amours des Salamandres Aquatiques , retorts upon himself."

The author commences this paper by stating the necessity of distinguishing by separate appellations all such functions as measure the intensity of physical properties, which he considers rendered obvious by a reference to the controversy respecting motion. The subject of this controversy, he observes, was the measure of motion itself, it being contended on one hand that the motion of a body is always proportional to its weight multiplied by its velocity; this opinion being supported by reference to the properties of the common centre of gravity of systems, &c.; while on the other hand the affections of elastic bodies in collision, and the general law of the conservation of living or active forces, were adduced in support of the latter measure. No sooner, however, were the terms “momentum” and “impetus” introduced into the science of mechanics, than the opinions of the contending parties were reconciled by the removal of every ground of dispute. In the Bakerian lecture on the force of percussion, read to this Society in 1806, he observes, it is remarked, that neither impetus nor momentum are usually correct measures of the effective action of machines. The criterion of this is the force exerted, multiplied by the space through which it acts, and this measure numerically expressed has been denominated duty by Mr. Watt; and the raising of one pound one foot high has been by him made the dynamic unit; according to which estimate, the duty performed by one bushel of coals, of 84 pounds, has been found to vary from 30 to 50 millions of such units, according to the nature of the engine, and the mode of combustion. To the measure or function represented by the force applied, multiplied by the space through which it acts, the author, however, proposes to give the name efficiency, retaining the word duty for a similar function, indicative of the work performed; and by a comparison of these two functions, viz. the efficiency expended on, and the duty performed by, any machine, an exact measure of its intrinsic work will be obtained.

The error of which this paper contains a correction, consists in the adoption of one exact second in arc, for the value of a division of the long level of the repeating circle with which the observations were made by the author for determining the amount of atmospheric refraction at Port Bowen, an account of which is published in the Transactions of the Royal Society for 1826, Part IV.; whereas the true value is 10",-9 in arc. The error was discovered by Captain Kater, who had occasion to use the instrument, and by him communicated to the author, who immediately took measures to ascertain the fact; and having, in Captain Kater’s presence, convinced himself of its reality, hastened to make the necessary recomputations of the Tables affected by it, and to submit them, so corrected, to the Society; explaining at the same time the error to have arisen from erroneous information, given him at the time of receiving the instrument, which being the same with that used by Captain Sabine in his pendulum experiments, he took no steps to examine the point; as it never once occurred to him that there could be a doubt on the subject. The Tables affected by this error are the 7th, 8th, 9th, 10th, 11th, and 12th; and the corrections, which fortunately in the three former Tables do not exceed 6", and in the three latter do not amount to 2", are stated. The author observes, in a postscript, that the observations given by Lieutenant Ross, at the end of the paper alluded to, must be now wholly rejected, in consequence of the original observations involving the erroneous datum dependent on the level being left on board the Fury at the time of her loss.

In this paper the author details the processes which, from long experience in the treatment of platina, he regards as the most effectual for rendering that metal perfectly malleable. When it is purified by solution in aqua regia, and precipitation with sal-ammoniac, sufficient care is seldom taken to avoid dissolving the iridium contained in the ore by due dilution of the solvent. The author states the exact degree of dilution requisite for this purpose, and the exact proportions in which the two acids are to be used. The digestion should be continued for three or four days, with a heat which ought gradually to be raised; and the fine pulverulent ore of iridium allowed to subside completely before the sal-ammoniac is added. The yellow precipitate thus obtained, after being well washed and pressed, must be heated with the utmost caution, so as to expel the sal-ammoniac, but at the same time to produce as little cohesion as possible among the particles of platina. It is then to be reduced to powder, first by rubbing between the hands, and next by grinding the coarser parts in a wooden mortar with a wooden pestle; because the friction of any harder substance would, by producing burnished surfaces, render them incapable of being welded together by heat. The whole is then to be well washed in clean water. In this process the mechanical diffusion through water is made to answer the same purposes as liquefaction by heat in the case of the other metals; the earthy impurities being carried to the surface by their superior lightness, and the effect of fluxes being accomplished by the solvent powers of water.

There are very few popular beliefs of any duration, however extravagant or incredible, that cannot be traced to some foundation in truth, however much distorted by ignorance, superstition or folly; and we have a remarkable instance of this in the celebrated Upas, or Poison Tree of Java, whose shade was believed to extinguish life in the unhappy beings who sought refuge under it. It was stated to be in a valley in the interior of Java, but it was surrounded with so many terrors, that its exact locality was not likely to be well defined or understood; and in this uncertainty originated the fables which have so long been before the public. I am indebted to Sir Charles Forbes, for a copy of a letter addressed to the late W. Taylor Money, Esq., Consul-General at Venice, from a gentleman who visited the Guwo-Upas, or Poisoned Valley, near Batur, in Java, on the 4th of July, 1830. I understand that the letter has appeared in print, but I have not seen it; and I deem it necessary to incorporate it in the present paper, to facilitate the comparisons and deductions I purpose making. A perusal of it will, I presume, afford satisfactory reasons to conclude, that in this deadly spot originated the belief in the Poison Tree, the mistake of the mephitic vapour escaping from vegetation, rather than from the soil, being natural and probable. The writer of the letter is a gentleman of the name of Loudon, an Englishman, but a landholder in Java, well known to Doctor Horsfield, and full reliance may be placed on the accuracy of his descriptions. He is disposed to question the resemblance between this Valley of Death and the Grotto del Cane, near to Naples; but I will endeavour to show that the difference is only in the physical features of the localities, and that the probability is, that the effects described originate in precisely similar causes. Dr. Horsfield informs me that he was at Batur in 1815 and 1816, and aware of the vicinity of the poisonous valley, but the natives refused to conduct him to it.

In this paper, which is a sequel to that published in the Philosophical Transactions for 1830, the author prosecutes the series of experiments he had commenced on the dilatation of the metals: pursuing the comparison between the results of the experiments of Dulong and Petit, with those given by his own instrument. He finds a striking accordance between them in the case of copper, as he had already done with respect to iron and platina. He gives the result of some trials which he made with a view to obtain registers of uniform composition, so as to preclude the necessity of determining the rate of expansion in each individual instance. The results of his experiments on the dilatation of the metals are given in tables; the first showing in arcs of the scales the expansions of four metals from 62° to 212°, and thence to 662° of Fahrenheit; and their respective melting points: and the second, exhibiting the expansion of certain alloys to the same points. The experiments on the melting point of cast iron give a mean of 2768°, and present a remarkable coincidence with the corrected temperature deduced from the expansion of a platina bar, plunged into melted cast iron, which was 2786°; thus affording a conclusive proof of the accuracy of the pyrometer, and of its competency to determine fixed and comparable points of very high temperature. The author accordingly thinks himself warranted in recommending the introduction of the instrument extensively in all arts and manufactures, where it is an object to regulate high temperatures, and where it is calculated to determine many questions of the highest importance both to practical and theoretical science.

The author, in a paper read to the Society in the year 1827, and printed in the Philosophical Transactions, gave an account of some experiments showing that the resistance of fluids increases in a ratio considerably higher than the square of the velocity, and that the absolute resistance is smaller than had been deduced from the experiments of the French Academy. In the present communication he states the results of his further inquiries on this subject. His experiments were made at the East India Docks, on a boat twenty-three feet long and six wide, with the stem and stern nearly vertical; one end being terminated by an angle of 42°, and the other of 72°; and the resistance to the boat’s motion being measured by a dynamometer. The results are given in tables: and it appears from them, that in light vessels sharpness is more important in the bow than in the stern; but that the reverse is the case in vessels carrying heavy cargoes. From another series of experiments the author infers that the resistance to a flat surface does not exceed 1.25lb. for each square foot, at a speed of one mile per hour; increasing, for greater velocities, in a ratio considerably higher than the square of the velocity. The author concludes with some observations on the results lately obtained in Scotland, where great velocities were given to boats moving on canals, without a proportional increase of resistance.

The author has examined the structure of the crystalline lens of the eye of a great variety of animals belonging to each of the four classes of Vertebrata; and has communicated in this paper a detailed account of his observations, arranged according as they relate to structures more and more complex. In a former paper, published in the Philosophical Transactions for 1833, the lens of the Cod fish was taken as the type of the simplest of these structures, in as much as all the fibres of which it is composed converge, like the meridians of a globe, to two opposite points, or poles, of a spheroid or lenticular solid; both of which poles are situated in the axis of vision. The structure which ranks next in respect of simplicity is that exhibited in the Salmon, among fishes; in the Gecko, among reptiles; and in the Hare, among Mammalia. It presents at each pole two septa placed in one continuous line, in different points of which all the fibres proceeding from the one surface to the other have their origin and termination. A structure somewhat more complex is met with in the lenses of most of the Mammalia, and is particularly exemplified in the lion, the tiger, the horse, and the ox. Three septa occur at each pole in the form of diverging lines inclined to one another at angles of 120°. The next degree of complexity is presented in the lens of the whale, the seal, and the bear, which contain, instead of three, four septa on each side, placed at right angles to each other in the form of a cross. In some specimens of lenses of whales and seals the author observed two septa from each pole, forming one continuous line, from each of the extremities of which proceeded two others, which were at right angles relatively to one another : so that there were in all five on each surface. The most complex structure is that of the lens of the elephant, which exhibits three primary septa diverging at equal angles from the pole, and at their extremities bifurcating into two additional septa, which are inclined to each other at angles of 60°, these latter being the real septa, to which the fibrous radiations are principally related. In some lenses of the elephant the author found the three septa immediately proceeding from the poles exceedingly short, and approaching to evanescence ; so that he has no doubt that occasionally they may be found to have disappeared, and that the other six septa will then all diverge from the poles, like the radii ot a hexagon, at angles of 60°. In all the preceding cases, where the arrangement of the fibres is symmetrical on the two sides, the septa on the opposite surface of the lens occupy positions which are reversed with respect to one another; thus in the simple case of the double septa at each pole, the line formed by those of the posterior surface is situated at right angles to that formed by the septa of the anterior surface. Where there are three divergent septa at each pole, the direction of those on the one side bisect the angles formed by those on the other side; and again, where the septa form a rectangular cross, those of one surface are inclined 45° to those of the other surface.

The Advanced Encryption Standard (AES) enables secure transmission of confidential messages. Since its invention, there have been many proposed attacks against the scheme. For example, one can inject errors or faults to acquire the encryption keys. It has been shown that the AES algorithm itself does not provide a protection against these types of attacks. Therefore, additional techniques like error control codes (ECCs) have been proposed to detect active attacks. However, not all the proposed solutions show the adequate efficacy. For instance, linear ECCs have some critical limitations, especially when the injected errors are beyond their fault detection or tolerance capabilities. In this paper, we propose a new method based on a non-linear code to protect all four internal stages of the AES hardware implementation. With this method, the protected AES system is able to (a) detect all multiplicity of errors with a high probability and (b) correct them if the errors follow certain patterns or frequencies. Results shows that the proposed method provides much higher security and reliability to the AES hardware implementation with minimal overhead.

In the paper referred to it said, "Let V stand for the integral in the equations(7.), and supposing that p and r 2 vary so as always to satisfy that equation, we shall have d V/ d p d p + dd V/ זdr = 0." Now the error alluded to consists in having given a wrong sign to the differential d V/ זdr , the value of which, as has been said, is modified, in the question under consi­deration, by the equation (7.). This mistake vitiates the concluding part of the paper in pp. 63, 64, 65, as far as relates to the limits of the quantities p and ז 2 . M. Liousville has done the author of the paper the honour of noticing and correcting the mistake in his Journal de Mathématiques for April 1839. When the sign of the dif­ferential is rightly ascertained, the analysis pursued in the paper leads to a simple determination of the limits sought, as this Note will prove, the propriety of printing which in the Philosophical Transactions is submitted to the Council.

The magical perfection of the designs delineated by light on the prepared tablets of M. Daguerre, and the extreme sensitiveness of his photographic material, render the discovery of inappreciable value to art and science. It appeared to me unfortunate, that a process which promised to improve our perceptions of the beautiful, and which placed in the hands of the scientific observer an instrument of wonderful delicacy, should have its utility circumscribed by its expense and inconvenience. Had the art of engraving the Daguerreotype tablets, or any other mode of multiplying copies of the original designs been discovered, nothing further would have been desired; but as it was, it appeared to be of the greatest importance, that means should be sought for of using some lighter and less expensive material.

Virtual reality (VR) offers potential as a prototyping tool for human-robot interaction. We explored a way to utilize human-centered design (HCD) methodology to develop a collaborative VR game for understanding teens' perceptions of, and interactions with, social robots. Our paper features three stages of the design process for teen-robot interaction in VR; ideation, prototyping, and the game development. In the ideation stage, we identified three important design principles: collaboration, customization, and robot characterization. In the prototyping stage, we developed a card game, conducted gameplay, and confirmed our design principles. Finally, we developed a low-fidelity VR game and received teens' feedback. This exploratory study highlights the potential of VR, both for collaborative robot design and teen-robot interaction studies.

In this communication the author describes a series of experiments, made for the purpose of determining the distribution of the voltaic force from its source in the generating metal, as indicated by the de­position of reduced copper in the constant battery; and, considering that the voltaic combination most perfect in theory would be one formed by a solid sphere, or point, of the generating metal, sur­rounded by a hollow sphere of the conducting metal, with an inter­vening liquid electrolyte, he constructed an apparatus making as near an approximation as possible to these conditions. It consisted of two hollow brass hemispheres, applied to each other by exterior flanges, and rendered water-tight by an intervening collar of leather. In the centre of the hollow sphere thus formed, a ball of amalgamated zinc was suspended by a well-varnished copper wire, connected with one of the cups of a galvanometer, and was contained in a mem­branous bag holding the acid solution ; the whole being introduced through a short tube in the top of the upper hemisphere, and the remaining space being filled with a saturated solution of sulphate of copper. The galvanic circuit was completed by wires establishing connexions between either hemisphere and the other cup of the galva­nometer. For measuring the forces developed, sometimes the ordi­nary magnetic, but in the greater number of instances the calorific galvanometer of De la Rive was employed; the indications given by these instruments were noted, on the completion of the circuit, in various ways; and the deposition of copper in the hemispheres was examined after the apparatus had been in action for a certain number of hours. The following are the conclusions which the author deduced from a series of experiments thus conducted: 1st. The force emanating from the active zinc centre diffuses itself over every part of the upper hemisphere, from which there is a good conducting passage for its circulation.

The theory of the author is founded on the two following propositions, namely, that 1. Every atom of matter consists of an immense sphere of force, varying inversely as the square of the distance from the centre ; this force being attractive at all distances, except in a small concentric sphere, in which it is repulsive. 2. Atoms differ from each other in their absolute forces, or in the extent of their spheres of repulsion, or in both these respects. The author assumes that there are four classes of atoms, the tenacious , the electric , the ethereal , and the aromatic . The existence of the last-named class of atoms he infers from the phenomena of vegetation, the miasmata of marshes, the aroma of plants, various noxious effluvia, the disinfecting property of some bodies, and facts relating to animalcules, and their ova, &c. He regards the two propositions which constitute the great principles of his theory, as presenting, at once, a complete explication of the general attributes of matter and body, with the Newtonian laws of motion, not otherwise theoretically explicable.