Search

In the present paper we study how subsystems of a normative system can be combined, and the role of such combinations for the understanding of hypothetical legal consequences. A combination of two subsystems is often accomplished by a normative correlation or an intermediate concept. To obtain a detailed analysis of such phenomena we use an algebraic framework. Normative systems are represented as algebraic structures over sets of conditions. This representation makes it possible to study normative systems using an extension of the theory of Boolean algebras, called the theory of Boolean quasi-orderings.

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.

Survey of research papers is not an easy task for novice researchers, because they are not always good at finding all appropriate keywords for the survey. Moreover, it is not easy for them to understand positions of papers in their research fields instantly, even when they use famous search engines like Google Scholar, it may often take a long time for them to find scholarly literature. On the other hand, many researchers have presented citation visualization techniques for surveying research papers. However, it is still often difficult to observe the complicated relations across multiple research fields or traverse the entire relations in their interest. In this paper, we proposed a visualization technique for citation networks applying topic-based paper clustering. Our technique categorizes papers applying LDA (Latent Dirichlet Allocation), and constructs clustered networks consisting of the papers.

We focus on one of the central concepts of case-based reasoning: similarity. In the field of sentencing, where the really decided cases are often on the harder side, similarity is multidimensional and depends less on formal rules than on various legitimate principles, objectives and factors which relate to the offender, the victim, the act and its social context. The paper presents our data base of empirically analysed cases of fraud and discusses two of the different phases completed to reduce complexity: (1) a decision topology whose categories emerged from in-depth interviews with judges, Crown and defense attorneys and which proved to be statistically significant; (2) experimenting with FXS, a program designed to retrieve similar cases based on their degree of salience. The salience coefficient used is a measure of similarity based on relative high or low frequency of factors in their local context. Particularly promising, although not yet formally explained, are FXS' flexible weighting possibilities.

This paper describes a new weighting sub-system for fruit sorting and grading machinery. Based on a fixed point DSP, it controls up to 10 lines at 20 fruit/second with an accuracy of /spl plusmn/1 gram. The system applies an adaptive filtering and a posterior deconvolution of the behaviour of the load sensor using an ARMA model. A final estimation procedure to obtain weight in grams is also described. The best results have been obtained with an ALMS algorithm for the adaptive filter.

Due to the high importance of economic dispatch in planning and operating electric power systems, new methods have been researched to minimize the costs of power generation. To calculate these costs, the power generation of each thermal unit must be evaluated. When a thermal unit is modelled considering real world constraints, such as multiple fuels and valve point effect, traditional optimization methods are inefficient due to the nature of the cost function. This paper shows a study of a metaheuristic method, based on flower pollination to search for satisfactory results for economic dispatch. The results obtained are compared with results from other authors, with the purpose of evaluating how efficient the technique presented here is.

In technical study programs on the bachelor level the focus is mainly directed on the scientific education in theory and practice. Publication is usually started during the PhD phase when students write their first scientific papers. During the last years some very successful projects were made at the university of applied sciences Regensburg to motivate bachelor students doing their first own small publications. The results of these projects are presented in this paper and ideas how students can publish are given.

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...

One of the problems in disease prevention and epidemics control is the large level of uncertainty present in the solved problems. If an optimization of targeted vaccination scheme is attempted, the evaluation of solutions usually involves simulating the non-deterministic spreading of the disease. However, the non-determinism of the epidemic dynamics is just one of the sources of uncertainty in this problem. This paper studies another source of uncertainty in optimization of targeted vaccination schemes, which is the existence of non-diagnosed cases of the disease.

Machine vision based automatic apparatus is a necessary component of an automated production line. In this paper, taking can-end surface defect detection as an example, we presented a visual inspector and proposed a new surface defect detection framework. Firstly, the Region of Interest (ROI) of the input image is got by circle detection and prior radius knowledge of can-end. Then, the saliency map and texture filtering image are computed to overcome the problems of irregular texture and non-uniform illumination. Finally, all suspected defects are obtained by saliency map segmentation, connected component analysis. Following, the size, the average saliency value and the mean texture filtering value of each suspected defective region are calculated, and the 3-dimensional features are used to distinguish true defects in the central panel region of can-end. We employ the designed equipment to grab can-end images and do tests divided into four groups on the grabbed images. The accuracy is 98.16% and the execution time is about 65.7 milliseconds. Experimental results demonstrate that the proposed method can inspect faint and low contrast defect accurately. Meanwhile, the proposed method is simple and computationally efficient and meets the high speed of industrial automation.

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.

Additive manufacturing (AM) systems present tremendous advantages over the traditional manufacturing systems, particularly for realizing complex shapes and producing custom parts. These advantages, and the rapid growth in the availability of AM systems, have led to a widespread increase in the use of AM. Unfortunately, general design for additive manufacturing (DfAM) tools that predict the engineering performance of AM parts are largely unavailable, and this has forced engineers to rely on engineering judgment and/or data from physical experiments. The data sets reported in the literature that quantify the performance of the existing AM systems provide much needed insight, but the data produced by experiments conducted on specific AM systems are necessarily of limited applicability. Given the large number of AM systems currently in use today, a potentially vast amount of data are needed to fully understand them all, and new AM systems and materials are being developed almost daily. To mitigate this need for an ever-increasing amount of data, this paper proposes the use of an approximation-assisted multi-objective optimization technique to quantify the performance of an AM system for specific design application in a targeted fashion. This general approach uses a limited number of physical experiments to answer a specific DfAM question of interest, and the results can then be used to design functional parts without the need for additional data. The implementation of the proposed approach is demonstrated with a material extrusion case study.

This paper proposed smart agricultural framework over RCAS in CATV network. The proposed framework adopts RCAS, which is a security system which is dedicated to cable television system, as a data protection system, and cable two-way broadband network as a communication channels among smart agricultural service participants.

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.

Synthetic Aperture Radar (SAR) image classification is becoming increasingly important in military or scientific research. SAR image classification based on unsupervised learning usually requires optimization of some metrics. Local optimization techniques frequently fail because functions of these metrics with respect to transformation parameters are generally nonconvex and irregular and, therefore, global methods are often required. In this paper, a new evolutionary approach, particle swarm optimization, is adapted for SAR image classification. The new algorithm composes of three main processes: firstly, selecting training samples for every region in the SAR image. Secondly, training these samples using PSO, and obtain clustering center of every region. Finally, output the classification result of SAR image according to clustering center obtained. To show the effectiveness of this approach, experiment with simulated SAR image was considered. The classification results are evaluated by comparing with two well-known algorithms, K-means and fuzzy K-menas. According to the overall accuracy and Kappa coefficient, PSO has high classification precision and can be used in SAR images classification.

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 the first part of this paper the author adduces proofs of the efficacy of telescopes constructed with fluid lenses, on the principles developed in his two former papers, published in the Philosophical Transactions, in separating double stars, resolving nebulae, and exhibiting different appearances in the discs of the planets. He institutes, with this view, a comparison between the performance of his telescope of 8 inches aperture and 12 feet in length, with Mr. Herschel’s telescope, made with his new 20 inches speculum, and with Sir James South’s new refractor, of 12 inches aperture and 20 feet focal length. In Mr. Barlow’s telescope ɳ Persei, which is marked as double in South and Herschel’s catalogue, is seen distinctly sextuple. The stars composing σ Orionis, marked in the catalogue as two distinct sets of stars, each triple, are shown in Mr. Barlow’s telescope as being both quadruple, with two very fine stars between them. A very fine double star was discovered by Mr. Herschel between the two which compose β Capricorni, and was considered by him as a very severe test: this star is seen distinctly in Mr. Barlow’s telescope, but not double.

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.

This essay is a sequel of the one which appeared in the last volume of the Philosophical Transactions, and which contained a general me­thod for reducing all the most important problems of dynamics to the study of one characteristic function, or one central or radical relation. It was there remarked that many eliminations required by this me­thod might be avoided by a general transformation, introducing the time explicitly into a part (S) of the whole characteristic function (V) ; and the first object of the present essay is to examine and develope the properties of this part (S), which the author designates by the term Principal Function . This function is applied by the author to problems of perturbation, in which he finds it dispenses with many laborious and circuitous processes, and furnishes accurate expressions of the disturbed configurations of a system by the rules of undisturbed motion, if only the initial components of velocities be changed in a suitable manner. Another manner of extending rigorously to dis­turbed, the rules of undisturbed motion, by the gradual variation of elements, in number double the number of the coordinates or other marks of position of the system, which was first invented by Lagrange, and was afterwards improved by Poisson, is considered in this second essay under a form rather more general; and the general method of calculation which has already been applied by the author to other analogous questions in optics and in dynamics, is now applied to the integration of the equations which determine these elements. This general method is founded chiefly on a combination of the principle of variations with those of partial differentials, and may furnish, when matured, a separate branch of analysis, which may be denominated the Calculus of Principal Functions . When applied to the integra­tion of the equations of varying elements, it suggests the consideration of a certain Function of Elements , capable of being variously trans­formed, and which may be either rigorously determined, or at least approached to, by a corollary of the general method. With a view to illustrate these new principles, and more especially those connected with problems of perturbation, they are applied, in this essay, first, to a very simple example, suggested by the motions of projectiles, the parabolic path being treated as the undisturbed; and secondly, to the problem of determining the motions of a ternary or multiple system, with any laws of attraction or repulsion, and with one pre­dominant mass. This latter problem, which was touched upon in the former essay, is here resumed in a new manner, by forming and in­tegrating the differential equations of a new set of varying elements, entirely distinct in theory (though little differing in practice) from the elements conceived by Lagrange; and having this advantage, that the differentials of all the new elements for both the disturbed and disturbing masses may be expressed by the coefficients of one disturbing function.

Peculiar difficulty has hitherto attended the determination of the equation of the curve formed by the perpetual intersection of rays, which, diverging from a luminous point, are reflected by a polished surface of a given curvature. Curves of this description have been denominated caustics; and the method usually employed to discover their polar equations, or the relation between the radius vector of any point of the curve and the tangent at that point, is both long and inelegant, and is considered by the author as involving considerable inaccuracy of reasoning. He proposes, therefore, to substitute a new method of investigation, by taking the polar equation of one of the reflected rays, and differentiating this equation with respect to the arbitrary quantities solely which determine its position, and thus obtaining the polar co-ordinates of the point of intersection of two consecutive lines $ and finally, by elimination, the equation of the curve in which all such points are found. He is thus led to results remarkable for their simplicity, elegance, and generality: and he gives particular applications of his method, exemplifying the facility with which it effects the solution of problems extremely difficult of management by the ordinary methods hitherto employed. His method is also applicable to the determination of the equations of the evolutes of curves, and to various other problems of a similar nature.

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.

Data Assimilation (DA) is an uncertainty quantification technique used to incorporate observed data into a prediction model in order to improve numerical forecasted results. Variational DA (VarDA) is based on the minimisation of a function which estimates the discrepancy between numerical results and observations. Operational forecasting requires real-time data assimilation. This mandates the choice of opportune methods to improve the efficiency of VarDA codes without loosing accuracy. Due to the scale of the forecasting area and the number of state variables used to describe the physical model, DA is a big data problem. In this paper, the Truncated Singular Value Decomposition (TSVD) is used to reduce the space dimension, alleviate the computational cost and reduce the errors. Nevertheless, a consequence is that important information is lost if the truncation parameter is not properly chosen. We provide an algorithm to compute the optimal truncation parameter and we prove that the optimal estimation reduces the ill-conditioning and removes the statistically less significant modes which could add noise to the estimate obtained from DA. In this paper, numerical issues faced in developing VarDA algorithm include the ill-conditioning of the background covariance matrix, the choice of a preconditioning and the choice of the regularisation parameter. We also show how the choice of the regularisation parameter impacts on the efficiency of the VarDA minimisation computed by the L-BFGS (Limited – Broyden Fletcher Goldfarb Shanno). Experimental results are provided for pollutant dispersion within an urban environment.