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Sample records for diophantine frobenius problem

  1. Achievements and Problems in Diophantine Approximation Theory

    NASA Astrophysics Data System (ADS)

    Sprindzhuk, V. G.

    1980-08-01

    ContentsIntroduction I. Metrical theory of approximation on manifolds § 1. The basic problem § 2. Brief survey of results § 3. The principal conjecture II. Metrical theory of transcendental numbers § 1. Mahler's classification of numbers § 2. Metrical characterization of numbers with a given type of approximation § 3. Further problems III. Approximation of algebraic numbers by rationals § 1. Simultaneous approximations § 2. The inclusion of p-adic metrics § 3. Effective improvements of Liouville's inequality IV. Estimates of linear forms in logarithms of algebraic numbers § 1. The basic method § 2. Survey of results § 3. Estimates in the p-adic metric V. Diophantine equations § 1. Ternary exponential equations § 2. The Thue and Thue-Mahler equations § 3. Equations of hyperelliptic type § 4. Algebraic-exponential equations VI. The arithmetic structure of polynomials and the class number § 1. The greatest prime divisor of a polynomial in one variable § 2. The greatest prime divisor of a polynomial in two variables § 3. Square-free divisors of polynomials and the class number § 4. The general problem of the size of the class number Conclusion References

  2. The diophantine equation hard problem (DEHP) as an asymmetric primitive - Is it possible?

    NASA Astrophysics Data System (ADS)

    Kamel Ariffin, Muhammad Rezal

    2013-09-01

    We put forward a probable hard problem based on a Diophantine equation that has characteristics to become an asymmetric primitive. Motivated by rearranging the equation representing the RSA modulus, N together with its Euler-phi function, φ(N) we define the Diophantine Equation Hard Problem (DEHP) on a definitive setting. Relation between the RSA factorization problem, RSA's e-th root problem and the DEHP is also discussed. A proposed asymmetric cryptosystem that manipulates DEHP together with the difficulty of factoring a product of strong primes is presented.

  3. General Power Sums of Integers That Are, and Are Not, Represented in the Two-Element Frobenius Problem

    ERIC Educational Resources Information Center

    Gauthier, N.

    2008-01-01

    A general method is presented for evaluating the sums of "m"th powers of the integers that can, and that cannot, be represented in the two-element Frobenius problem. Generating functions are introduced and used for that purpose. Explicit formulas for the desired sums are obtained and specific examples are discussed.

  4. Diophantine Optics

    NASA Astrophysics Data System (ADS)

    Rouan, D.

    2016-09-01

    What I call Diophantine optics is the exploitation in optics of some remarkable algebraic relations between powers of integers. The name comes from Diophantus of Alexandria, a greek mathematician, known as the father of algebra. He studied polynomial equations with integer coefficients and integer solutions, called diophantine equations. Since constructive or destructive interferences are playing with optical path differences which are multiple integer (odd or even) of λ/2 and that the complex amplitude is a highly non-linear function of the optical path difference (or equivalently of the phase), one can understand that any Taylor development of this amplitude implies powers of integers. This is the link with Diophantine equations. We show how, especially in the field of interferometry, remarkable relations between powers of integers can help to solve several problems, such as achromatization of a phase shifter or deep nulling efficiency. It appears that all the research that was conducted in this frame of thinking, relates to the field of detection of exoplanets, a very active domain of astrophysics today.

  5. Diophantine networks

    NASA Astrophysics Data System (ADS)

    Bedogne', C.; Masucci, A. P.; Rodgers, G. J.

    2008-03-01

    We introduce a new class of deterministic networks by associating networks with Diophantine equations, thus relating network topology to algebraic properties. The network is formed by representing integers as vertices and by drawing cliques between M vertices every time that M distinct integers satisfy the equation. We analyse the network generated by the Pythagorean equation x2 +y2 =z2 showing that its degree distribution is well approximated by a power law with exponential cut-off. We also show that the properties of this network differ considerably from the features of scale-free networks generated through preferential attachment. Remarkably we also recover a power law for the clustering coefficient. We then study the network associated with the equation x2 +y2 = z showing that the degree distribution is consistent with a power law for several decades of values of k and that, after having reached a minimum, the distribution begins rising again. The power-law exponent, in this case, is given by γ ∼ 4.5 We then analyse clustering and ageing and compare our results to the ones obtained in the Pythagorean case.

  6. Recent Progress on Certain Quartic Diophantine Equations

    NASA Astrophysics Data System (ADS)

    Walsh, P. G.

    2008-01-01

    Wilhelm Ljunggren proved many results on quartic Diophantine equations of the form aX4-bY2 = c, with c∈{±1,-2,±4}. Noticeably absent from this set of values of c is c = 2. We describe some recent progress on this problem, and discuss some open problems which require further study.

  7. Diophantine Equations and Computation

    NASA Astrophysics Data System (ADS)

    Davis, Martin

    Unless otherwise stated, we’ll work with the natural numbers: N = \\{0,1,2,3, dots\\}. Consider a Diophantine equation F(a1,a2,...,an,x1,x2,...,xm) = 0 with parameters a1,a2,...,an and unknowns x1,x2,...,xm For such a given equation, it is usual to ask: For which values of the parameters does the equation have a solution in the unknowns? In other words, find the set: \\{ mid exists x_1,ldots,x_m [F(a_1,ldots,x_1,ldots)=0] \\} Inverting this, we think of the equation F = 0 furnishing a definition of this set, and we distinguish three classes: a set is called Diophantine if it has such a definition in which F is a polynomial with integer coefficients. We write \\cal D for the class of Diophantine sets.

  8. On the Diophantine equation

    NASA Astrophysics Data System (ADS)

    Zahari, N. M.; Sapar, S. H.; Mohd Atan, K. A.

    2013-04-01

    This paper discusses an integral solution (a, b, c) of the Diophantine equations x3n+y3n = 2z2n for n ≥ 2 and it is found that the integral solution of these equation are of the form a = b = t2, c = t3 for any integers t.

  9. Diophantine frequency synthesis.

    PubMed

    Sotiriadis, Paul Peter

    2006-11-01

    A methodology for fine-step, fast-hopping, low-spurs phase-locked loop based frequency synthesis is presented. It uses mathematical properties of integer numbers and linear Diophantine equations to overcome the constraining relation between frequency step and phase-comparator frequency that is inherent in conventional phase-locked loop based frequency synthesis. The methodology leads to fine-step, fast-hopping, modular-structured frequency synthesizers with potentially very low spurs, especially in the vicinity of the carrier. The paper focuses on the mathematical principles of the new methodology and the related number theoretic algorithms. PMID:17091835

  10. Un scindage du morphisme de Frobenius quantique

    NASA Astrophysics Data System (ADS)

    Gros, Michel; Kaneda, Masaharu

    2015-10-01

    We show that the quantum Frobenius morphism constructed by Lusztig in the setting of the quantum enveloping algebra specialized at a root of unity admits a (nonunital) multiplicative splitting. We construct the splitting using a basis of the toral part of the small quantum algebra consisting of pairwise orthogonal idempotents summing up to 1, and likewise in the modular case of the algebra of distributions for a semisimple algebraic group.

  11. New Hardness Results for Diophantine Approximation

    NASA Astrophysics Data System (ADS)

    Eisenbrand, Friedrich; Rothvoß, Thomas

    We revisit simultaneous Diophantine approximation, a classical problem from the geometry of numbers which has many applications in algorithms and complexity. The input to the decision version of this problem consists of a rational vector α ∈ ℚ n , an error bound ɛ and a denominator bound N ∈ ℕ + . One has to decide whether there exists an integer, called the denominator Q with 1 ≤ Q ≤ N such that the distance of each number Q ·α i to its nearest integer is bounded by ɛ. Lagarias has shown that this problem is NP-complete and optimization versions have been shown to be hard to approximate within a factor n c/ loglogn for some constant c > 0. We strengthen the existing hardness results and show that the optimization problem of finding the smallest denominator Q ∈ ℕ + such that the distances of Q·α i to the nearest integer are bounded by ɛ is hard to approximate within a factor 2 n unless {textrm{P}} = NP.

  12. Symmetry and Lie-Frobenius reduction of differential equations

    NASA Astrophysics Data System (ADS)

    Gaeta, G.

    2015-01-01

    Twisted symmetries, widely studied in the last decade, have proved to be as effective as standard ones in the analysis and reduction of nonlinear equations. We explain this effectiveness in terms of a Lie-Frobenius reduction; this requires focus not just on the prolonged (symmetry) vector fields, but on the distributions spanned by these and on systems of vector fields in involution in the Frobenius sense, not necessarily spanning a Lie algebra. Research partially supported by MIUR-PRIN program under project 2010-JJ4KPA.

  13. On some applications of diophantine approximations

    PubMed Central

    Chudnovsky, G. V.

    1984-01-01

    Siegel's results [Siegel, C. L. (1929) Abh. Preuss. Akad. Wiss. Phys.-Math. Kl. 1] on the transcendence and algebraic independence of values of E-functions are refined to obtain the best possible bound for the measures of irrationality and linear independence of values of arbitrary E-functions at rational points. Our results show that values of E-functions at rational points have measures of diophantine approximations typical to “almost all” numbers. In particular, any such number has the “2 + ε” exponent of irrationality: ǀΘ - p/qǀ > ǀqǀ-2-ε for relatively prime rational integers p,q, with q ≥ q0 (Θ, ε). These results answer some problems posed by Lang. The methods used here are based on the introduction of graded Padé approximations to systems of functions satisfying linear differential equations with rational function coefficients. The constructions and proofs of this paper were used in the functional (nonarithmetic case) in a previous paper [Chudnovsky, D. V. & Chudnovsky, G. V. (1983) Proc. Natl. Acad. Sci. USA 80, 5158-5162]. PMID:16593441

  14. On some applications of diophantine approximations.

    PubMed

    Chudnovsky, G V

    1984-03-01

    Siegel's results [Siegel, C. L. (1929) Abh. Preuss. Akad. Wiss. Phys.-Math. Kl. 1] on the transcendence and algebraic independence of values of E-functions are refined to obtain the best possible bound for the measures of irrationality and linear independence of values of arbitrary E-functions at rational points. Our results show that values of E-functions at rational points have measures of diophantine approximations typical to "almost all" numbers. In particular, any such number has the "2 + epsilon" exponent of irrationality: Theta - p/q > q(-2-epsilon) for relatively prime rational integers p,q, with q >/= q(0) (Theta, epsilon). These results answer some problems posed by Lang. The methods used here are based on the introduction of graded Padé approximations to systems of functions satisfying linear differential equations with rational function coefficients. The constructions and proofs of this paper were used in the functional (nonarithmetic case) in a previous paper [Chudnovsky, D. V. & Chudnovsky, G. V. (1983) Proc. Natl. Acad. Sci. USA 80, 5158-5162]. PMID:16593441

  15. Average Frobenius distribution for the degree two primes of a number field

    NASA Astrophysics Data System (ADS)

    James, Kevin; Smith, Ethan

    2013-05-01

    Let $K$ be a number field and $r$ an integer. Given an elliptic curve $E$, defined over $K$, we consider the problem of counting the number of degree two prime ideals of $K$ with trace of Frobenius equal to $r$. Under certain restrictions on $K$, we show that "on average" the number of such prime ideals with norm less than or equal to $x$ satisfies an asymptotic identity that is in accordance with standard heuristics. This work is related to the classical Lang-Trotter conjecture and extends the work of several authors.

  16. Evolution equations: Frobenius integrability, conservation laws and travelling waves

    NASA Astrophysics Data System (ADS)

    Prince, Geoff; Tehseen, Naghmana

    2015-10-01

    We give new results concerning the Frobenius integrability and solution of evolution equations admitting travelling wave solutions. In particular, we give a powerful result which explains the extraordinary integrability of some of these equations. We also discuss ‘local’ conservations laws for evolution equations in general and demonstrate all the results for the Korteweg-de Vries equation.

  17. Polynomials Satisfying Functional and Differential Equations and Diophantine Properties of Their Zeros

    NASA Astrophysics Data System (ADS)

    Calogero, Francesco; Yi, Ge

    2013-06-01

    By investigating the behavior of two solvable isochronous N-body problems in the immediate vicinity of their equilibria, functional equations satisfied by the para-Jacobi polynomial {pN (0, 1; γ; x )} and by the Jacobi polynomial {PN^{(-N-1,-N-1 )} (x )} (or, equivalently, by the Gegenbauer polynomial {CN^{-N-1/2}( x ) }) are identified, as well as Diophantine properties of the zeros and coefficients of these polynomials.

  18. ON FROBENIUS PAIRS OF THE FORM (F\\leftthreetimes V,\\, V)

    NASA Astrophysics Data System (ADS)

    Shunkov, V. P.

    1991-02-01

    A nonsimplicity test for groups is obtained which is connected with certain Frobenius pairs. In the case of finite groups it is a natural complement to Glauberman's familiar Z^*-theorem.Bibliography: 10 titles.

  19. On a conjecture on exponential Diophantine equations

    NASA Astrophysics Data System (ADS)

    Cipu, Mihai; Mignotte, Maurice

    We study the solutions of a Diophantine equation of the form $a^x+b^y=c^z$, where $a\\equiv 2 \\pmod 4$, $b\\equiv 3 \\pmod 4$ and $\\gcd (a,b,c)=1$. The main result is that if there exists a solution $(x,y,z)=(2,2,r)$ with $r>1$ odd then this is the only solution in integers greater than 1, with the possible exception of finitely many values $(c,r)$. We also prove the uniqueness of such a solution if any of $a$, $b$, $c$ is a prime power. In a different vein, we obtain various inequalities that must be satisfied by the components of a putative second solution.

  20. Integer Solutions of a Special Diophantine Equation

    NASA Astrophysics Data System (ADS)

    Özkoç, Arzu; Tekcan, Ahmet

    2011-09-01

    Let t≠1 be an integer. In this work, we determine the integer solutions of Diophantine equation D:x2+(2-t2)y2+(-2t2-2t+2)x+(2t5-6t3+4t)y-t8+4t6-4t4+2t3+t2-2t = 0 over Z and also over finite fields Fp for primes p≥2. Also we derive some recurrence relations on the integer solutions (xn,yn) of D and formulate the the n—th solution (xn,yn) by using the simple continued fraction expansion of xn/yn.

  1. Frobenius-norm-based measures of quantum coherence and asymmetry.

    PubMed

    Yao, Yao; Dong, G H; Xiao, Xing; Sun, C P

    2016-01-01

    We formulate the Frobenius-norm-based measures for quantum coherence and asymmetry respectively. In contrast to the resource theory of coherence and asymmetry, we construct a natural measure of quantum coherence inspired from optical coherence theory while the group theoretical approach is employed to quantify the asymmetry of quantum states. Besides their simple structures and explicit physical meanings, we observe that these quantities are intimately related to the purity (or linear entropy) of the corresponding quantum states. Remarkably, we demonstrate that the proposed coherence quantifier is not only a measure of mixedness, but also an intrinsic (basis-independent) quantification of quantum coherence contained in quantum states, which can also be viewed as a normalized version of Brukner-Zeilinger invariant information. In our context, the asymmetry of N-qubit quantum systems is considered under local independent and collective transformations. In- triguingly, it is illustrated that the collective effect has a significant impact on the asymmetry measure, and quantum correlation between subsystems plays a non-negligible role in this circumstance. PMID:27558009

  2. Frobenius-norm-based measures of quantum coherence and asymmetry

    PubMed Central

    Yao, Yao; Dong, G. H.; Xiao, Xing; Sun, C. P.

    2016-01-01

    We formulate the Frobenius-norm-based measures for quantum coherence and asymmetry respectively. In contrast to the resource theory of coherence and asymmetry, we construct a natural measure of quantum coherence inspired from optical coherence theory while the group theoretical approach is employed to quantify the asymmetry of quantum states. Besides their simple structures and explicit physical meanings, we observe that these quantities are intimately related to the purity (or linear entropy) of the corresponding quantum states. Remarkably, we demonstrate that the proposed coherence quantifier is not only a measure of mixedness, but also an intrinsic (basis-independent) quantification of quantum coherence contained in quantum states, which can also be viewed as a normalized version of Brukner-Zeilinger invariant information. In our context, the asymmetry of N-qubit quantum systems is considered under local independent and collective transformations. In- triguingly, it is illustrated that the collective effect has a significant impact on the asymmetry measure, and quantum correlation between subsystems plays a non-negligible role in this circumstance. PMID:27558009

  3. Diophantine exponents for mildly restricted approximation

    NASA Astrophysics Data System (ADS)

    Bugeaud, Yann; Kristensen, Simon

    2009-10-01

    We are studying the Diophantine exponent μ n, l defined for integers 1≤ l< n and a vector α∈ℝ n by letting μ_{n,l}=sup\\{μ≥0: 0 < Vertx\\cdotαVert

  4. Analysis of Quadratic Diophantine Equations with Fibonacci Number Solutions

    ERIC Educational Resources Information Center

    Leyendekkers, J. V.; Shannon, A. G.

    2004-01-01

    An analysis is made of the role of Fibonacci numbers in some quadratic Diophantine equations. A general solution is obtained for finding factors in sums of Fibonacci numbers. Interpretation of the results is facilitated by the use of a modular ring which also permits extension of the analysis.

  5. Superconformal block quivers, duality trees and Diophantine equations

    NASA Astrophysics Data System (ADS)

    Hanany, Amihay; He, Yang-Hui; Sun, Chuang; Sypsas, Spyros

    2013-11-01

    We generalize previous results on = 1, (3 + 1)-dimensional superconformal block quiver gauge theories. It is known that the necessary conditions for a theory to be superconformal, i.e. that the beta and gamma functions vanish in addition to anomaly cancellation, translate to a Diophantine equation in terms of the quiver data. We re-derive results for low block numbers revealing an new intriguing algebraic structure underlying a class of possible superconformal fixed points of such theories. After explicitly computing the five block case Diophantine equation, we use this structure to reorganize the result in a form that can be applied to arbitrary block numbers. We argue that these theories can be thought of as vectors in the root system of the corresponding quiver and superconformality conditions are shown to associate them to certain subsets of imaginary roots. These methods also allow for an interpretation of Seiberg duality as the action of the affine Weyl group on the root lattice.

  6. The Diophantine equation 8(x) + p(y) = z(2).

    PubMed

    Qi, Lan; Li, Xiaoxue

    2015-01-01

    Let p be a fixed odd prime. Using certain results of exponential Diophantine equations, we prove that (i) if p ≡ ± 3(mod  8), then the equation 8 (x) + p (y) = z (2) has no positive integer solutions (x, y, z); (ii) if p ≡ 7(mod  8), then the equation has only the solutions (p, x, y, z) = (2 (q) - 1, (1/3)(q + 2), 2, 2 (q) + 1), where q is an odd prime with q ≡ 1(mod  3); (iii) if p ≡ 1(mod  8) and p ≠ 17, then the equation has at most two positive integer solutions (x, y, z). PMID:25654128

  7. The Diophantine Equation 8x + py = z2

    PubMed Central

    Qi, Lan; Li, Xiaoxue

    2015-01-01

    Let p be a fixed odd prime. Using certain results of exponential Diophantine equations, we prove that (i) if p ≡ ±3(mod  8), then the equation 8x + py = z2 has no positive integer solutions (x, y, z); (ii) if p ≡ 7(mod  8), then the equation has only the solutions (p, x, y, z) = (2q − 1, (1/3)(q + 2), 2, 2q + 1), where q is an odd prime with q ≡ 1(mod  3); (iii) if p ≡ 1(mod  8) and p ≠ 17, then the equation has at most two positive integer solutions (x, y, z). PMID:25654128

  8. Multi-Matrix Models and Noncommutative Frobenius Algebras Obtained from Symmetric Groups and Brauer Algebras

    NASA Astrophysics Data System (ADS)

    Kimura, Yusuke

    2015-07-01

    It has been understood that correlation functions of multi-trace operators in SYM can be neatly computed using the group algebra of symmetric groups or walled Brauer algebras. On the other hand, such algebras have been known to construct 2D topological field theories (TFTs). After reviewing the construction of 2D TFTs based on symmetric groups, we construct 2D TFTs based on walled Brauer algebras. In the construction, the introduction of a dual basis manifests a similarity between the two theories. We next construct a class of 2D field theories whose physical operators have the same symmetry as multi-trace operators constructed from some matrices. Such field theories correspond to non-commutative Frobenius algebras. A matrix structure arises as a consequence of the noncommutativity. Correlation functions of the Gaussian complex multi-matrix models can be translated into correlation functions of the two-dimensional field theories.

  9. Bounds for departure from normality and the Frobenius norm of matrix eigenvalues

    SciTech Connect

    Lee, S.L.

    1994-12-01

    New lower and upper bounds for the departure from normality and the Frobenius norm of the eigenvalues of a matrix axe given. The significant properties of these bounds axe also described. For example, the upper bound for matrix eigenvalues improves upon the one derived by Kress, de Vries and Wegmann in [Lin. Alg. Appl., 8 (1974), pp. 109-120]. The upper bound for departure from normality is sharp for any matrix whose eigenvalues are collinear in the complex plane. Moreover, the latter formula is a practical estimate that costs (at most) 2m multiplications, where m is the number of nonzeros in the matrix. In terms of applications, the results can be used to bound from above the sensitivity of eigenvalues to matrix perturbations or bound from below the condition number of the eigenbasis of a matrix.

  10. Lepton mixing, residual symmetries, and trigonometric Diophantine equations

    NASA Astrophysics Data System (ADS)

    Hu, Bo

    2014-10-01

    In this paper, we study residual symmetries in the lepton sector. Our first concern is the symmetry of the charged lepton mass matrix in the basis where the Majorana neutrino mass matrix is diagonal, which is strongly constrained by the requirement that the symmetry group generated by residual symmetries is finite. In a recent work, R. M. Fonseca and W. Grimus found that there exists a set of constraint equations that can be completely solved, which is essential in their approach to the classification of lepton mixing matrices that are fully determined by residual symmetries. In this paper, a method to handle trigonometric Diophantine equations is introduced. We will show that the constraint equations found by Fonseca and Grimus can also be solved by this method. Detailed derivation and discussion will be presented in a self-contained way. In addition, we will also show that, in the case where residual symmetries satisfy a reality condition, this method can be used to solve the equation constraining parameters in the symmetry assignment that controls the group structure generated by residual symmetries and is directly related to mixing matrix elements.

  11. Spectrum and eigenfunctions of the Frobenius-Perron operator of the tent map

    NASA Astrophysics Data System (ADS)

    Dörfle, M.

    1985-07-01

    The spectrum and eigenfunctions of the Frobenius-Perron operator induced by the tent map are discussed in detail. Special attention is paid to the case where the critical point of the map lies on an aperiodic trajectory and the differences from maps with a periodic critical trajectory are stressed. It is shown that the relevant eigenvalues of the spectrum are not sensitive to the aperiodicity of the critical trajectory. All other parts of the spectrum and all eigenfunctions in particular are changed drastically if the critical trajectory becomes aperiodic. The intimate connection between the point spectrum and the kneading invariant is established and the critical slowing down as well as the band splitting are a consequence of its properties. The structure of the infinite sequence of null spaces and its implications on the spectrum of the operator are discussed. It is shown that any initial distribution P(0, x) of bounded variation can be projected uniquely onto the eigenfunctions of the relevant eigenvalues and that the time dependence of P(n, x) is determined by this expansion up to an error O(η n). From this the stationary and the asymptotic behavior of the correlation function < x(n) x> can be derived exactly.

  12. A study of the ambiguity in the solutions to the Diophantine equation for Chern numbers

    NASA Astrophysics Data System (ADS)

    Avron, J. E.; Kenneth, O.; Yehoshua, G.

    2014-05-01

    The Chern numbers for Hofstadter models with rational flux 2πp/q are partially determined by a Diophantine equation. A mod q ambiguity remains. The resolution of this ambiguity is only known for the rectangular lattice with nearest neighbors hopping where it has the form of a ‘window condition’. We study a Hofstadter butterfly on the triangular lattice for which the resolution of ambiguity is open. In the model many pairs (p, q) satisfy a window condition which is shifted relative to the window of the square model. However, we also find pairs (p, q) where the Chern numbers do not belong to any contiguous window. This shows that the rectangular model and the one we study on the triangular lattice are not adiabatically connected: many gaps must close. Our results suggest the conjecture that the mod q ambiguity in the Diophantine equation generically reduces to a sign ambiguity.

  13. On the Diophantine equation x^2+q^2m=2y^p

    NASA Astrophysics Data System (ADS)

    Tengely, Sz

    In this paper we consider the Diophantine equation $x^2+q^{2m}=2y^p$ where $m,p,q,x,y$ are integer unknowns with $m>0,$ $p$ and $q$ are odd primes and $\\gcd(x,y)=1.$ We prove that there are only finitely many solutions $(m,p,q,x,y)$ for which $y$ is not a sum of two consecutive squares. We also study the above equation with fixed $y$ and with fixed $q.$

  14. On the System of Diophantine Equations x2 − 6y2 = −5 and x = az2 − b

    PubMed Central

    Zhang, Silan; Chen, Jianhua; Hu, Hao

    2014-01-01

    Mignotte and Pethö used the Siegel-Baker method to find all the integral solutions (x, y, z) of the system of Diophantine equations x2 − 6y2 = −5 and x = 2z2 − 1. In this paper, we extend this result and put forward a generalized method which can completely solve the family of systems of Diophantine equations x2 − 6y2 = −5 and x = az2 − b for each pair of integral parameters a, b. The proof utilizes algebraic number theory and p-adic analysis which successfully avoid discussing the class number and factoring the ideals. PMID:25045739

  15. On the system of Diophantine equations x2 - 6y2 = -5 and x = az2 - b.

    PubMed

    Zhang, Silan; Chen, Jianhua; Hu, Hao

    2014-01-01

    Mignotte and Pethö used the Siegel-Baker method to find all the integral solutions (x, y, z) of the system of Diophantine equations x (2) - 6y (2) = -5 and x = 2z (2) - 1. In this paper, we extend this result and put forward a generalized method which can completely solve the family of systems of Diophantine equations x (2) - 6y (2) = -5 and x = az (2) - b for each pair of integral parameters a, b. The proof utilizes algebraic number theory and p-adic analysis which successfully avoid discussing the class number and factoring the ideals. PMID:25045739

  16. Mathemimetics I: Self-computational prime-number line and three-dimensional Diophantine equation matrix

    NASA Astrophysics Data System (ADS)

    Trell, Erik

    2012-09-01

    Emulating Nature by observation and ground-up application of its patterns, structures and processes is a classical scientific practice which under the designation of Biomimetics has now been brought to the Nanotechnology scale where even highly complex systems can be replicated by continuous or cyclically reiterated assembly of the respective self-similar real-world eigen-elements, modules and algorithms right from their infinitesimal origin. This is actually quite akin to the genuine mathematical art and can find valuable renewed use as here exemplified by an onedimensional prime-number line and a three-dimensional Diophantine Equation Universe embodiment.

  17. Persistence of Diophantine flows for quadratic nearly integrable Hamiltonians under slowly decaying aperiodic time dependence

    NASA Astrophysics Data System (ADS)

    Fortunati, Alessandro; Wiggins, Stephen

    2014-09-01

    The aim of this paper is to prove a Kolmogorov type result for a nearly integrable Hamiltonian, quadratic in the actions, with an aperiodic time dependence. The existence of a torus with a prefixed Diophantine frequency is shown in the forced system, provided that the perturbation is real-analytic and (exponentially) decaying with time. The advantage consists in the possibility to choose an arbitrarily small decaying coefficient consistently with the perturbation size. The proof, based on the Lie series formalism, is a generalization of a work by A. Giorgilli.

  18. Linear forms in p-adic logarithms and the Diophantine equation formula here

    NASA Astrophysics Data System (ADS)

    Bugeaud, Yann

    1999-11-01

    A longstanding conjecture claims that the Diophantine equationformula herehas finitely many solutions and, maybe, only those given byformula hereAmong the known results, let us mention that Ljunggren [9] solved (1) completely when q = 2 and that very recently Bugeaud et al. [3] showed that (1) has no solution when x is a square. For more information and in particular for finiteness type results under some extra hypotheses, we refer the reader to Nagell [11], Shorey & Tijdeman [16, 17] and to the recent survey of Shorey [15]. One of the main tools used in most of the proofs is Baker's theory of linear form in archimedean logarithms of algebraic numbers and especially a dramatic sharpening obtained when the algebraic numbers involved are closed to 1. This was first noticed by Shorey [14], and has been applied in numerous works relating to (1) or to the Diophantine equationformula heresee for instance [1, 5, 10]. The purpose of the present work is to prove a similar sharpening for linear forms in p-adic logarithms and to show how it can be applied in the context of (1). Further, following previous investigations by Sander [12] and Saradha & Shorey [13], we derive from our results an irrationality statement for Mahler's numbers.

  19. Modelling Problem-Solving Situations into Number Theory Tasks: The Route towards Generalisation

    ERIC Educational Resources Information Center

    Papadopoulos, Ioannis; Iatridou, Maria

    2010-01-01

    This paper examines the way two 10th graders cope with a non-standard generalisation problem that involves elementary concepts of number theory (more specifically linear Diophantine equations) in the geometrical context of a rectangle's area. Emphasis is given on how the students' past experience of problem solving (expressed through interplay…

  20. The local Hurwitz constant and Diophantine approximation on Hecke groups

    NASA Astrophysics Data System (ADS)

    Lehner, J.

    1990-10-01

    Define the Hecke group by {G_q} = < {( {begin{array}{*{20}{c}} 1 & {{⪉mb... ...{array}{*{20}{c}} 0 & { - 1} 1 & 0 } )} rangle , {λ _q} = 2cos π /q , q = 3,4, ldots . We call {G_q}(∞ ) the {G_q} -rationals, and R - {G_q}(∞ ) the {G_q} -irrationals. The problem we treat here is the approximation of {G_q} -irrationals by {G_q} -rationals. Let M(α ) be the upper bound of numbers c for which \\vertα - k/m\\vert < 1/c{m^2} for all {G_q} -irrationals and infinitely many k/m in {G_q}(∞ ) . Set h_q'= {inf _α }M(α ) . We call h_q' the Hurwitz constant for {G_q} . It is known that h_q'= 2 , q even; h_q'= 2{(1 + {(1 - {λ _q}/2)^2})^{1/2}} , q odd. In this paper we prove this result by using {λ _q} -continued fractions, as developed previously by D. Rosen. Write α - frac{{{P_{n - 1}}}}{{{Q_{n - 1}}}} = frac{{{{( - 1)}^{... ...}{\\varepsilon _2} \\cdots {\\varepsilon _n}}}{{{m_{n - 1}}(α )Q_{n - 1}^2}}, where {\\varepsilon _i} = ± 1 and {P_i}/{Q_i} are the convergents of the {λ _q} -continued fraction for α . Then M(α ) = {overline {lim } _n}{m_n}(α ) . We call {m_n}(α ) the local Hurwitz constant. In the final section we prove some results on the local Hurwitz constant. For example (Theorem 4), it is shown that if q is odd and {\\varepsilon _{n + 1}} = {\\varepsilon _{n + 2}} = + 1 , then {m_i} ≥ {(λ _q^2 + 4)^{1/2}} > h_q' for at least one of i = n - 1,n,n + 1 .

  1. Ergodic theory and Diophantine approximation for translation surfaces and linear forms

    NASA Astrophysics Data System (ADS)

    Athreya, Jayadev; Parrish, Andrew; Tseng, Jimmy

    2016-08-01

    We derive results on the distribution of directions of saddle connections on translation surfaces using only the Birkhoff ergodic theorem applied to the geodesic flow on the moduli space of translation surfaces. Our techniques, together with an approximation argument, also give an alternative proof of a weak version of a classical theorem in multi-dimensional Diophantine approximation due to Schmidt (1960 Can. J. Math. 12 619–31, 1964 Trans. Am. Math. Soc. 110 493–518). The approximation argument allows us to deduce the Birkhoff genericity of almost all lattices in a certain submanifold of the space of unimodular lattices from the Birkhoff genericity of almost all lattices in the whole space and similarly for the space of affine unimodular lattices.

  2. Hall conductance, topological quantum phase transition, and the Diophantine equation on the honeycomb lattice

    NASA Astrophysics Data System (ADS)

    Sato, Masatoshi; Tobe, Daijiro; Kohmoto, Mahito

    2008-12-01

    We consider a tight-binding model with the nearest-neighbor hopping integrals on the honeycomb lattice in a magnetic field. Assuming one of the three hopping integrals, which we denote by ta , can take a different value from the two others, we study quantum phase structures controlled by the anisotropy of the honeycomb lattice. For weak and strong ta regions, the Hall conductances are calculated algebraically by using the Diophantine equation. Except for a few specific gaps, we completely determine the Hall conductances in these two regions including those for subband gaps. In a weak magnetic field, it is found that the weak ta region shows the unconventional quantization of the Hall conductance, σxy=-(e2/h)(2n+1) (n=0,±1,±2,…) , near the half filling, while the strong ta region shows only the conventional one, σxy=-(e2/h)n (n=0,±1,±2,…) . From the topological nature of the Hall conductance, the existence of gap closing points and quantum phase transitions in the intermediate ta region is concluded. We also study numerically the quantum phase structure in detail and find that even when ta=1 , namely, in graphene case, the system is in the weak ta phase except when the Fermi energy is located near the Van Hove singularity or the lower and upper edges of the spectrum.

  3. Integrability, analyticity, isochrony, equilibria, small oscillations, and Diophantine relations: Results from the stationary Korteweg-de Vries hierarchy

    NASA Astrophysics Data System (ADS)

    Bruschi, M.; Calogero, F.; Droghei, R.

    2009-12-01

    The isochronous variant is exhibited of the dynamical system corresponding to the Mth ordinary differential equation of the stationary Korteweg-de Vries (KdV) hierarchy. New Diophantine relations are thereby obtained, in the guise of matrices of arbitrary order having integer eigenvalues or equivalently of polynomials of arbitrary degree having integer zeros. Generalizations of these formulas to relations among rational functions are also obtained. The basic idea to arrive at such relations is not new, but the specific application reported in this paper is new, and it is likely to open the way to several analogous new findings.

  4. On solving the Diophantine equation x^3+y^3+z^3=k on a vector computer

    NASA Astrophysics Data System (ADS)

    Heath-Brown, D. R.; Lioen, W. M.; Riele, H. J. J. Te

    1993-07-01

    Recently, the first author has proposed a new algorithm for solving the Diophantine equation {x^3} + {y^3} + {z^3} = k , where k is a given nonzero integer. In this paper we present the detailed versions of this algorithm for some values of k given below, and we describe how we have optimized and run the algorithm on a Cyber 205 vector computer. A vectorized version of the Euclidean algorithm was written, which is capable of solving the equations {w_i}{x_i} ≡ 1 bmod {n_i},i = 1,2, ldots , at vector speed. Moreover, the basic double-precision arithmetic operations ( + , - , × ,/) were vectorized. The following cases were implemented and run: k = 3,30,2,20,39 , and 42. For k = 3 a range was searched which includes the cube \\vert x\\vert,\\vert y\\vert,\\vert z\\vert ≤ {10^8} ; this considerably extends an earlier search in the cube \\vert x\\vert,\\vert y\\vert,\\vert z\\vert ≤ {2^{16}} . No solutions were found apart from the known ones (1, 1, 1) and (4,4, - 5) . For k = 30 , which probably is, with k = 3 , the case which has attracted most attention in the literature, no solution was found. It is the smallest case for which no solution is known and for which one has not been able to find a proof that no solution exists. For k = 2 a parametric form solution is known, but we also found one which does not belong to this parametric form, viz., (1214928,3480205, - 3528875) . For k = 20 , several new large solutions were found in addition to several known ones; this case served as a (partial) check of the correctness of our program. Finally, for k = 39 we found the first solution: (134476,117367, - 159380) . Hence, this case can be dropped from the list of values of k (k = 30,33,39,42, ldots ) for which no solution is known (yet).

  5. Goldfishing: A new solvable many-body problem

    NASA Astrophysics Data System (ADS)

    Bruschi, M.; Calogero, F.

    2006-10-01

    A recent technique allows one to identify and investigate solvable dynamical systems naturally interpretable as classical many-body problems, being characterized by equations of motion of Newtonian type (generally in two-dimensional space). In this paper we tersely review results previously obtained in this manner and present novel findings of this kind: mainly solvable variants of the goldfish many-body model, including models that feature isochronous classes of completely periodic solutions. Different formulations of these models are presented. The behavior of one of these isochronous dynamical systems in the neighborhood of its equilibrium configuration is investigated, and in this manner some remarkable Diophantine findings are obtained.

  6. Public Channel Cryptography: Chaos Synchronization and Hilbert's Tenth Problem

    NASA Astrophysics Data System (ADS)

    Kanter, Ido; Kopelowitz, Evi; Kinzel, Wolfgang

    2008-08-01

    The synchronization process of two mutually delayed coupled deterministic chaotic maps is demonstrated both analytically and numerically. The synchronization is preserved when the mutually transmitted signals are concealed by two commutative private filters, a convolution of the truncated time-delayed output signals or some powers of the delayed output signals. The task of a passive attacker is mapped onto Hilbert’s tenth problem, solving a set of nonlinear Diophantine equations, which was proven to be in the class of NP-complete problems [problems that are both NP (verifiable in nondeterministic polynomial time) and NP-hard (any NP problem can be translated into this problem)]. This bridge between nonlinear dynamics and NP-complete problems opens a horizon for new types of secure public-channel protocols.

  7. Public channel cryptography: chaos synchronization and Hilbert's tenth problem.

    PubMed

    Kanter, Ido; Kopelowitz, Evi; Kinzel, Wolfgang

    2008-08-22

    The synchronization process of two mutually delayed coupled deterministic chaotic maps is demonstrated both analytically and numerically. The synchronization is preserved when the mutually transmitted signals are concealed by two commutative private filters, a convolution of the truncated time-delayed output signals or some powers of the delayed output signals. The task of a passive attacker is mapped onto Hilbert's tenth problem, solving a set of nonlinear Diophantine equations, which was proven to be in the class of NP-complete problems [problems that are both NP (verifiable in nondeterministic polynomial time) and NP-hard (any NP problem can be translated into this problem)]. This bridge between nonlinear dynamics and NP-complete problems opens a horizon for new types of secure public-channel protocols. PMID:18764616

  8. A solvable many-body problem, its equilibria, and a second-order ordinary differential equation whose general solution is polynomial

    NASA Astrophysics Data System (ADS)

    Calogero, Francesco

    2013-01-01

    Some properties of a solvable N-body problem featuring several free parameters ("coupling constants") are investigated. Restrictions on its parameters are reported which guarantee that all its solutions are completely periodic with a fixed period independent of the initial data (isochrony). The restrictions on its parameters which guarantee the existence of equilibria are also identified. In this connection a remarkable second-order ODE—generally not of hypergeometric type, hence not reducible to those characterizing the classical polynomials—is studied: if its parameters satisfy a Diophantine condition, its general solution is a polynomial of degree N, the N zeros of which identify the equilibria of the N-body system.

  9. Baroclinic Instability in the Solar Tachocline. II. The Eady Problem

    NASA Astrophysics Data System (ADS)

    Gilman, Peter A.

    2016-02-01

    We solve the nongeostrophic baroclinic instability problem for the tachocline for a continuous model with a constant vertical rotation gradient (the Eady problem), using power series generated by the Frobenius method. The results confirm and greatly extend those from a previous two-layer model. For effective gravity G independent of height, growth rates and ranges of unstable longitudinal wavenumbers m and latitudes increase with decreasing G. As with the two-layer model, the overshoot tachocline is much more unstable than the radiative tachocline. The e-folding growth times range from as short as 10 days to as long as several years, depending on latitude, G, and wavenumber. For a more realistic effective gravity that decreases linearly from the radiative interior to near zero at the top of the tachocline, we find that only m = 1, 2 modes are unstable, with growth rates somewhat larger than for constant G, with the same value as at the bottom of the tachocline. All results are the same whether we assume that the vertical velocity or the perturbation pressure is zero at the top of the layer; this is a direct consquence of not employing the geostrophic assumption for perturbations. We explain most of the properties of the instability in terms of the Rossby deformation radius. We discuss further improvements in the realism of the model, particularly adding toroidal fields that vary in height, and including latitudinal gradients of both rotation and toroidal fields.

  10. Diophantine equations in the primes

    NASA Astrophysics Data System (ADS)

    Cook, Brian; Magyar, Ákos

    2014-12-01

    Let $\\mathfrak{p}=(\\mathfrak{p}_1,...,\\mathfrak{p}_r)$ be a system of $r$ polynomials with integer coefficients of degree $d$ in $n$ variables $\\mathbf{x}=(x_1,...,x_n)$. For a given $r$-tuple of integers, say $\\mathbf{s}$, a general local to global type statement is shown via classical Hardy-Littlewood type methods which provides sufficient conditions for the solubility of $\\mathfrak{p}(\\mathbf{x})=\\mathbf{s}$ under the condition that each of the $x_i$'s is prime.

  11. On applications of diophantine approximations

    PubMed Central

    Chudnovsky, G. V.

    1984-01-01

    This paper is devoted to the study of the arithmetic properties of values of G-functions introduced by Siegel [Siegel, C. L. (1929) Abh. Preuss. Akad. Wiss. Phys.-Math. Kl. 1]. One of the main results is a theorem on the linear independence of values of G-functions at rational points close to the origin. In this theorem, no conditions are imposed on the p-adic convergence of a G-function at a generic point. The theorem finally realizes Siegel's program on G-function values outlined in his paper. PMID:16593530

  12. A technique to identify solvable dynamical systems, and another solvable extension of the goldfish many-body problem

    NASA Astrophysics Data System (ADS)

    Calogero, Francesco

    2004-12-01

    We take advantage of the simple approach, recently discussed, which associates to (solvable) matrix equations (solvable) dynamical systems interpretable as (interesting) many-body problems, possibly involving auxiliary dependent variables in addition to those identifying the positions of the moving particles. Starting from a solvable matrix evolution equation, we obtain the corresponding many-body model and note that in one case the auxiliary variables can be altogether eliminated, obtaining thereby an (also Hamiltonian) extension of the "goldfish" model. The solvability of this novel model, and of its isochronous variant, is exhibited. A related, as well solvable, model, is also introduced, as well as its isochronous variant. Finally, the small oscillations of the isochronous models around their equilibrium configurations are investigated, and from their isochronicity certain diophantine relations are evinced.

  13. Problem Periods

    MedlinePlus

    ... gov/ Home Body Getting your period Problem periods Problem periods It’s common to have cramps or feel ... doctor Some common period problems Signs of period problems top One way to know if you may ...

  14. Balance Problems

    MedlinePlus

    ... it could be a sign of a balance problem. Balance problems can make you feel unsteady or as if ... related injuries, such as hip fracture. Some balance problems are due to problems in the inner ear. ...

  15. Balance Problems

    MedlinePlus

    ... often, it could be a sign of a balance problem. Balance problems can make you feel unsteady or as ... fall-related injuries, such as hip fracture. Some balance problems are due to problems in the inner ...

  16. Childbirth Problems

    MedlinePlus

    ... labor starts before 37 completed weeks of pregnancy Problems with the umbilical cord Problems with the position of the baby, such as ... feet first Birth injuries For some of these problems, the baby may need to be delivered surgically ...

  17. Balance Problems

    MedlinePlus

    ... version of this page please turn Javascript on. Balance Problems About Balance Problems Have you ever felt dizzy, lightheaded, or ... dizziness problem during the past year. Why Good Balance is Important Having good balance means being able ...

  18. Walking Problems

    MedlinePlus

    ... daily activities, get around, and exercise. Having a problem with walking can make daily life more difficult. ... walk is called your gait. A variety of problems can cause an abnormal gait and lead to ...

  19. Breathing Problems

    MedlinePlus

    ... re not getting enough air. Sometimes mild breathing problems are from a stuffy nose or hard exercise. ... emphysema or pneumonia cause breathing difficulties. So can problems with your trachea or bronchi, which are part ...

  20. Erection problems

    MedlinePlus

    ... cord injury In some cases, your emotions or relationship problems can lead to ED, such as: Poor ... you stressed, depressed, or anxious? Are you having relationship problems? You may have a number of different ...

  1. Joint Problems

    MedlinePlus

    ... ankles and toes. Other types of arthritis include gout or pseudogout. Sometimes, there is a mechanical problem ... for more information on osteoarthritis, rheumatoid arthritis and gout. How Common are Joint Problems? Osteoarthritis, which affects ...

  2. Balance Problems

    MedlinePlus

    ... our e-newsletter! Aging & Health A to Z Balance Problems Basic Facts & Information What are Balance Problems? Having good balance means being able to ... Only then can you “keep your balance.” Why Balance is Important Your feelings of dizziness may last ...

  3. Parking Problem

    ERIC Educational Resources Information Center

    Foster, Colin

    2012-01-01

    This is the story of a real problem, not a problem that is contrived, or invented for the convenience of the appropriate planning tool. This activity by a group of students, defined simply as "8FN", might be likened to an "end of term concert". If you just happened to be a delegate at the ATM Conference 2003 you might remember the analogy. Social…

  4. Urination Problems

    MedlinePlus

    ... back or groin? Yes You may have a KIDNEY STONE or another serious problem. EMERGENCY See your doctor ... the bladder, called INTERSTITIAL CYSTITIS, or from a KIDNEY STONE stuck in the bladder, or a chemical in ...

  5. Kidney Problems

    MedlinePlus

    ... our e-newsletter! Aging & Health A to Z Kidney Problems Basic Facts & Information The kidneys are two ... the production of red blood cells. What are Kidney Diseases? For about one-third of older people, ...

  6. Hearing Problems

    MedlinePlus

    ... This flow chart will help direct you if hearing loss is a problem for you or a family ... may damage the inner ear. This kind of hearing loss is called OCCUPATIONAL. Prevent occupational hearing loss by ...

  7. Sleep Problems

    MedlinePlus

    ... For Consumers Consumer Information by Audience For Women Sleep Problems Share Tweet Linkedin Pin it More sharing ... PDF 474KB) En Español Medicines to Help You Sleep Tips for Better Sleep Basic Facts about Sleep ...

  8. Thyroid Problems

    MedlinePlus

    ... treated differently. Common thyroid disorders and problems include: Hypothyroidism Hypothyroidism is a disorder in which your thyroid doesn’ ... normal after you get better. If you have hypothyroidism, however, the levels of T4 in your blood ...

  9. Nipple problems

    MedlinePlus

    ... Inverted nipple; Nipple problems Images Female breast Intraductal papilloma Mammary gland Abnormal discharge from the nipple Normal ... 8. Read More Breast cancer Endocrine glands Intraductal papilloma Update Date 11/16/2014 Updated by: Cynthia ...

  10. Vision problems

    MedlinePlus

    ... which nothing can be seen) Vision loss and blindness are the most severe vision problems. Causes Vision ... that look faded. The most common cause of blindness in people over age 60. Eye infection, inflammation, ...

  11. Swallowing problems

    MedlinePlus

    ... the home Dry mouth during cancer treatment Enteral nutrition - child - managing problems Gastrostomy feeding tube - bolus Jejunostomy feeding tube Mouth and neck radiation - discharge Multiple sclerosis - discharge Stroke - discharge Update Date 5/15/2014 ...

  12. Speech Problems

    MedlinePlus

    ... a person's ability to speak clearly. Some Common Speech Disorders Stuttering is a problem that interferes with fluent ... is a language disorder, while stuttering is a speech disorder. A person who stutters has trouble getting out ...

  13. Hopf and Frobenius algebras in conformal field theory

    NASA Astrophysics Data System (ADS)

    Singh, Sukreet

    With the current rapid depletion of non-renewable resources to generate power, energy conservation and on site generation have become the most critical aspects of the equation. Buildings should be so designed or retrofitted in order to generate its own electricity and cater to its own demand. This thesis looks as the ways in which we can do a post occupancy analysis of an existing institutional building of about 95,000 square feet that was built in 1960's in order to reduce usage and approach a Zero Net Energy goal. This case study building is Von Kleinsmid Centre (VKC) which is located at the heart of USC (University of Southern California). It is challenging to retrofit an existing institutional building because of its complexity and make it achieve a 'Zero Net Energy' goal. All the roadblocks, real life delays, software limitations that had to be overcome to achieve this result are explained in this thesis. The Zero Net Energy goal was achieved by calibrating energy model to the utility data of the building, providing various energy efficiency measures and generating on-site electricity.

  14. Puzzles & Problems.

    ERIC Educational Resources Information Center

    Murphy, Pat, Ed.

    1993-01-01

    "Exploring" is a magazine of science, art, and human perception, produced by Exploratorium in collaboration with other participating museums. This issue focuses on puzzles and problem solving. Brain teasers, puzzles, and the strategies for solving them are included. Features include: (1) "Homework Assignment #3" (Paul Doherty); (2) "The Case of…

  15. Heat Problems.

    ERIC Educational Resources Information Center

    Connors, G. Patrick

    Heat problems and heat cramps related to jogging can be caused by fluid imbalances, medications, dietary insufficiency, vomiting or diarrhea, among other factors. If the condition keeps reoccurring, the advice of a physician should be sought. Some preventive measures that can be taken include: (1) running during the cooler hours of the day; (2)…

  16. Padé approximations and diophantine geometry

    PubMed Central

    Chudnovsky, D. V.; Chudnovsky, G. V.

    1985-01-01

    Using methods of Padé approximations we prove a converse to Eisenstein's theorem on the boundedness of denominators of coefficients in the expansion of an algebraic function, for classes of functions, parametrized by meromorphic functions. This result is applied to the Tate conjecture on the effective description of isogenies for elliptic curves. PMID:16593552

  17. LETTER TO THE EDITOR: Diophantine integrability

    NASA Astrophysics Data System (ADS)

    Halburd, R. G.

    2005-04-01

    The heights of iterates of the discrete Painlevé equations over number fields appear to grow no faster than polynomials while the heights of generic solutions of non-integrable discrete equations grow exponentially. This gives rise to a simple and effective numerical test for the integrability of discrete equations. Numerical evidence and theoretical results are presented. Connections with other tests for integrability and Vojta's dictionary are discussed.

  18. Centaurs: Here, There, Everywhere!

    ERIC Educational Resources Information Center

    Dzlabenko, Dimitri; Ivril, Oleg

    2008-01-01

    Motivated by centaurs jumping around a circular stadium, we derive Kronecker's Approximation Theorem, which in turn provides elementary solutions to difficult problems in the theory of Diophantine approximations.

  19. Waring's problem with the Ramanujan \\tau-function

    NASA Astrophysics Data System (ADS)

    Garaev, M. Z.; Garcia, V. C.; Konyagin, S. V.

    2008-02-01

    We prove that for every integer N the Diophantine equation \\sum_{i=1}^{74000}\\tau(n_i)=N, where \\tau(n) is the Ramanujan \\tau-function, has a solution in positive integers n_1, n_2,\\dots, n_{74000} satisfying the condition \\max_{1\\le i\\le 74000}n_i\\,{\\ll}\\vert N\\vert^{2/11}+1. We also consider similar questions in residue fields modulo a large prime p.

  20. Problems with "n"th-Term Problems

    ERIC Educational Resources Information Center

    Matteson, Shirley M.

    2010-01-01

    An nth-term problem involves a sequence. Students must determine which expression will allow them to calculate the nth position of the sequence. To solve such problems, students are to find "a rule that determines the number of elements in a step from the step number." These types of problems help students develop concepts of functions, variables,…

  1. Class and Home Problems: Optimization Problems

    ERIC Educational Resources Information Center

    Anderson, Brian J.; Hissam, Robin S.; Shaeiwitz, Joseph A.; Turton, Richard

    2011-01-01

    Optimization problems suitable for all levels of chemical engineering students are available. These problems do not require advanced mathematical techniques, since they can be solved using typical software used by students and practitioners. The method used to solve these problems forces students to understand the trends for the different terms…

  2. The Chicken Problem.

    ERIC Educational Resources Information Center

    Reeves, Charles A.

    2000-01-01

    Uses the chicken problem for sixth grade students to scratch the surface of systems of equations using intuitive approaches. Provides students responses to the problem and suggests similar problems for extensions. (ASK)

  3. Screening for Breast Problems

    MedlinePlus

    f AQ FREQUENTLY ASKED QUESTIONS FAQ178 GYNECOLOGIC PROBLEMS Mammography and Other Screening Tests for Breast Problems • What ... used to screen for breast problems? • What is mammography? • Why is mammography done? • When should I start ...

  4. Problems with Smell

    MedlinePlus

    ... this page please turn Javascript on. Problems with Smell About Problems with Smell Our sense of smell helps us enjoy life. ... sec Click to watch this video Aging and Smell Loss Problems with smell increase as people get ...

  5. Sexual Problems in Men

    MedlinePlus

    ... problems may also be factors. Occasional problems with sexual function are common. If problems last more than a few months or cause distress for you or your partner, you should see your health care provider.

  6. Pelvic Support Problems

    MedlinePlus

    ... correct pelvic support problems? • Glossary What are pelvic support problems? The pelvic organs include the vagina , cervix , uterus , bladder , urethra , small intestines, and rectum . The pelvic ...

  7. Problem? "No Problem!" Solving Technical Contradictions

    ERIC Educational Resources Information Center

    Kutz, K. Scott; Stefan, Victor

    2007-01-01

    TRIZ (pronounced TREES), the Russian acronym for the theory of inventive problem solving, enables a person to focus his attention on finding genuine, potential solutions in contrast to searching for ideas that "may" work through a happenstance way. It is a patent database-backed methodology that helps to reduce time spent on the problem,…

  8. Quadratic eigenvalue problems.

    SciTech Connect

    Walsh, Timothy Francis; Day, David Minot

    2007-04-01

    In this report we will describe some nonlinear eigenvalue problems that arise in the areas of solid mechanics, acoustics, and coupled structural acoustics. We will focus mostly on quadratic eigenvalue problems, which are a special case of nonlinear eigenvalue problems. Algorithms for solving the quadratic eigenvalue problem will be presented, along with some example calculations.

  9. [The mind -- body problem].

    PubMed

    Pérez, Diana I

    2005-01-01

    In this paper I present, in the first place, two of the main problems in the philosophy of mind: 1) the problem of the criteria of the mental, and 2) the problem of the relationship between the mental and the physical. In the last part, I mention two problems highly discussed nowadays which, in my view, will produce the most important advance in the knowledge of our minds in the next decades: the problem of consciousness and its neural basis, and the problem of the origin and development of a theory of mind. PMID:16220149

  10. The Algorithm Selection Problem

    NASA Technical Reports Server (NTRS)

    Minton, Steve; Allen, John; Deiss, Ron (Technical Monitor)

    1994-01-01

    Work on NP-hard problems has shown that many instances of these theoretically computationally difficult problems are quite easy. The field has also shown that choosing the right algorithm for the problem can have a profound effect on the time needed to find a solution. However, to date there has been little work showing how to select the right algorithm for solving any particular problem. The paper refers to this as the algorithm selection problem. It describes some of the aspects that make this problem difficult, as well as proposes a technique for addressing it.

  11. Locating Problems with Quality Circles.

    ERIC Educational Resources Information Center

    White, Donald D.; Bednar, David A.

    1985-01-01

    Five categories of common quality circles problems are identified to help firms anticipate difficulties and avert circle failures. These categories include encountered internal problems, encountered external problems, created internal problems, created external problems, and interface problems. Solutions are suggested. (CT)

  12. Problem: Heart Valve Regurgitation

    MedlinePlus

    ... Pressure High Blood Pressure Tools & Resources Stroke More Problem: Heart Valve Regurgitation Updated:May 26,2016 What ... content was last reviewed May 2016. Heart Valve Problems and Disease • Home • About Heart Valves • Heart Valve ...

  13. Problem: Heart Valve Stenosis

    MedlinePlus

    ... Pressure High Blood Pressure Tools & Resources Stroke More Problem: Heart Valve Stenosis Updated:Aug 10,2016 About ... content was last reviewed May 2016. Heart Valve Problems and Disease • Home • About Heart Valves • Heart Valve ...

  14. Women and sexual problems

    MedlinePlus

    ... gov/ency/patientinstructions/000663.htm Women and sexual problems To use the sharing features on this page, ... feel better about your sex life. Common Sexual Problems You may have sexual dysfunction if you are ...

  15. Increases in Problem Drinking

    MedlinePlus

    ... review our exit disclaimer . Subscribe Increases in Problem Drinking Alcohol use disorder is becoming more common, a ... the need to better educate people about problem drinking and its treatment. Alcohol use disorder, or AUD, ...

  16. Sexual Problems in Women

    MedlinePlus

    There are many problems that can keep a woman from enjoying sex. They include Lack of sexual desire Inability to become aroused Lack of orgasm, or sexual climax Painful intercourse These problems may have physical or psychological causes. Physical causes ...

  17. Diabetic Eye Problems

    MedlinePlus

    ... this can damage your eyes. The most common problem is diabetic retinopathy. It is a leading cause ... surgery, with follow-up care. Two other eye problems can happen to people with diabetes. A cataract ...

  18. IT Problem Management

    NASA Video Gallery

    IT Problem Management – process responsible for managing Lifecycle of all IT problems. The primary objective is to prevent incidents from occurring and to minimize impact of incidents that cannot...

  19. Study the Problem.

    ERIC Educational Resources Information Center

    Choate, Joyce S.

    1990-01-01

    The initial step of a strategic process for solving mathematical problems, "studying the question," is discussed. A lesson plan for teaching students to identify and revise arithmetic problems is presented, involving directed instruction and supervised practice. (JDD)

  20. Puzzles Pastimes Problems.

    ERIC Educational Resources Information Center

    Eperson, D. B.

    1991-01-01

    This section includes eight problems to which the journal invites readers to respond. Problem topics include angles in alternate segments, pentominoes, a new triangle of numbers, cricket scores, symmetrical pentagons, inequalities, a pythagorean dissection, and magic squares. (MDH)

  1. Solving Word Problems.

    ERIC Educational Resources Information Center

    Karrison, Joan; Carroll, Margaret Kelly

    1991-01-01

    Students with language and learning disabilities may have difficulty solving mathematics word problems. Use of a sequential checklist, identifying clues and keywords, and illustrating a problem can all help the student identify and implement the correct computational process. (DB)

  2. Traveling with breathing problems

    MedlinePlus

    If you have breathing problems and you: Are short of breath most of the time Get short of breath when you walk 150 ... or less Have been in the hospital for breathing problems recently Use oxygen at home, even if ...

  3. Diabetes and Foot Problems

    MedlinePlus

    ... Disease, and Other Dental Problems Diabetic Eye Disease Diabetes and Foot Problems How can diabetes affect my feet? Too much glucose, also called ... you have any of these signs. How can diabetes change the shape of my feet? Nerve damage ...

  4. The molecular matching problem

    NASA Technical Reports Server (NTRS)

    Kincaid, Rex K.

    1993-01-01

    Molecular chemistry contains many difficult optimization problems that have begun to attract the attention of optimizers in the Operations Research community. Problems including protein folding, molecular conformation, molecular similarity, and molecular matching have been addressed. Minimum energy conformations for simple molecular structures such as water clusters, Lennard-Jones microclusters, and short polypeptides have dominated the literature to date. However, a variety of interesting problems exist and we focus here on a molecular structure matching (MSM) problem.

  5. The problem of simultaneity

    NASA Astrophysics Data System (ADS)

    Marx, G.

    Drake's formula for the possible number of independent civilizations in the Galaxy is discussed in the light of several new hypotheses (e.g., Lovelock's Gaia hypothesis). Emphasis is placed on ways to overcome the time problem, i.e., the problem of how to communicate with civilizations that may arise in the future. Electronic, nucleonic, and bionic approaches to this problem are discussed.

  6. TRAINING IN PROBLEM SOLVING.

    ERIC Educational Resources Information Center

    DEVANE, J.R.; RIMOLDI, H.J.A.

    CHANGES WERE STUDIED IN THE PROBLEM-SOLVING BEHAVIOR OF HIGH SCHOOL STUDENTS AS A FUNCTION OF A CAREFULLY DESIGNED TRAINING PROGRAM. TRAINING WAS DEFINED AS THE DEVELOPMENT OF STUDENT AWARENESS OF PROBLEM-SOLVING STRATEGIES USED. INSTRUMENTS WERE DEVELOPED AND REFINED TO MEASURE PROBLEM-SOLVING BEHAVIOR. SPECIFICALLY TESTED WAS THE FOLLOWING…

  7. Exploratory Problems in Mathematics.

    ERIC Educational Resources Information Center

    Stevenson, Frederick W.

    This book attempts to introduce students to the creative aspects of mathematics through exploratory problems. The introduction presents the criteria for the selection of the problems in the book. Criteria indicate that problems should: be immediately attractive, require data to be generated or gathered, appeal to students from junior high school…

  8. Grievance Procedure Problems.

    ERIC Educational Resources Information Center

    Green, Gary J.

    This paper presents two actual problems involving grievance procedures. Both problems involve pending litigation and one of them involves pending arbitration. The first problem occurred in a wealthy Minnesota school district and involved a seniority list. Because of changes in the financial basis for supporting public schools, it became necessary…

  9. Problem Solving by Design

    ERIC Educational Resources Information Center

    Capobianco, Brenda M.; Tyrie, Nancy

    2009-01-01

    In a unique school-university partnership, methods students collaborated with fifth graders to use the engineering design process to build their problem-solving skills. By placing the problem in the context of a client having particular needs, the problem took on a real-world appeal that students found intriguing and inviting. In this article, the…

  10. Techniques of Problem Solving.

    ERIC Educational Resources Information Center

    Krantz, Steven G.

    The purpose of this book is to teach the basic principles of problem solving in both mathematical and non-mathematical problems. The major components of the book consist of learning to translate verbal discussion into analytical data, learning problem solving methods for attacking collections of analytical questions or data, and building a…

  11. Mathematics as Problem Solving.

    ERIC Educational Resources Information Center

    Soifer, Alexander

    This book contains about 200 problems. It is suggested that it be used by students, teachers or anyone interested in exploring mathematics. In addition to a general discussion on problem solving, there are problems concerned with number theory, algebra, geometry, and combinatorics. (PK)

  12. [Doctors' alcohol problems].

    PubMed

    Florkowski, Antoni; Gruszczyński, Wojciech; Gałecki, Piotr; Szubert, Sławomir; Klus, Marek; Zboralski, Krzysztof

    2008-01-01

    An overusing and an addiction to alcoholic drinks are important problems in a medical society. The studies made in the United States had documented that about 8-12% doctors were addicted to alcohol. In many cases the doctors are able to keep their problem as a secret and their activity is satisfied up to the moment when a decrease is noticed. Some factors--such as a high level of stress--predispose doctors to alcoholic problems especially surgeons. Alcohol problems should be identified as early as possible, and therapy ought to be given as well. There is no reason to hide the problem. PMID:19025048

  13. Matrix interdiction problem

    SciTech Connect

    Pan, Feng; Kasiviswanathan, Shiva

    2010-01-01

    In the matrix interdiction problem, a real-valued matrix and an integer k is given. The objective is to remove k columns such that the sum over all rows of the maximum entry in each row is minimized. This combinatorial problem is closely related to bipartite network interdiction problem which can be applied to prioritize the border checkpoints in order to minimize the probability that an adversary can successfully cross the border. After introducing the matrix interdiction problem, we will prove the problem is NP-hard, and even NP-hard to approximate with an additive n{gamma} factor for a fixed constant {gamma}. We also present an algorithm for this problem that achieves a factor of (n-k) mUltiplicative approximation ratio.

  14. ROV overcomes deepwater problems

    SciTech Connect

    Frisbie, F.R.; Hughes, E.W.

    1984-09-01

    The use of remotely operated vehicles (ROVs) in supportive drill ships operating in more than 200 meters of water poses severe technical and operational problems. Defining these problems beforehand and addressing them during design, manufacture, testing and installation ensures a functional and effective support capability. Such problems as the availability of desk space, and the subsequent installation, maintenance, and the launch/recovery of the system are described.

  15. On Euler's problem

    SciTech Connect

    Egorov, Yurii V

    2013-04-30

    We consider the classical problem on the tallest column which was posed by Euler in 1757. Bernoulli-Euler theory serves today as the basis for the design of high buildings. This problem is reduced to the problem of finding the potential for the Sturm-Liouville equation corresponding to the maximum of the first eigenvalue. The problem has been studied by many mathematicians but we give the first rigorous proof of the existence and uniqueness of the optimal column and we give new formulae which let us find it. Our method is based on a new approach consisting in the study of critical points of a related nonlinear functional. Bibliography: 6 titles.

  16. Known TCP Implementation Problems

    NASA Technical Reports Server (NTRS)

    Paxson, Vern (Editor); Allman, Mark; Dawson, Scott; Fenner, William; Griner, Jim; Heavens, Ian; Lahey, K.; Semke, J.; Volz, B.

    1999-01-01

    This memo catalogs a number of known TCP implementation problems. The goal in doing so is to improve conditions in the existing Internet by enhancing the quality of current TCP/IP implementations. It is hoped that both performance and correctness issues can be resolved by making implementors aware of the problems and their solutions. In the long term, it is hoped that this will provide a reduction in unnecessary traffic on the network, the rate of connection failures due to protocol errors, and load on network servers due to time spent processing both unsuccessful connections and retransmitted data. This will help to ensure the stability of the global Internet. Each problem is defined as follows: Name of Problem The name associated with the problem. In this memo, the name is given as a subsection heading. Classification one or more problem categories for which the problem is classified: "congestion control", "performance", "reliability", "resource management". Description A definition of the problem, succinct but including necessary background material. Significance A brief summary of the sorts of environments for which the problem is significant.

  17. Tactical missile turbulence problems

    NASA Technical Reports Server (NTRS)

    Dickson, Richard E.

    1987-01-01

    Of particular interest is atmospheric turbulence in the atmospheric boundary layer, since this affects both the launch and terminal phase of flight, and the total flight for direct fire systems. Brief discussions are presented on rocket artillery boost wind problems, mean wind correction, turbulent boost wind correction, the Dynamically Aimed Free Flight Rocket (DAFFR) wind filter, the DAFFR test, and rocket wake turbulence problems. It is concluded that many of the turbulence problems of rockets and missiles are common to those of aircraft, such as structural loading and control system design. However, these problems have not been solved at this time.

  18. Specific Pronunciation Problems.

    ERIC Educational Resources Information Center

    Avery, Peter; And Others

    1987-01-01

    Reviews common pronunciation problems experienced by learners of English as a second language who are native speakers of Vietnamese, Cantonese, Spanish, Portuguese, Italian, Polish, Greek, and Punjabi. (CB)

  19. ITOUGH2 sample problems

    SciTech Connect

    Finsterle, S.

    1997-11-01

    This report contains a collection of ITOUGH2 sample problems. It complements the ITOUGH2 User`s Guide [Finsterle, 1997a], and the ITOUGH2 Command Reference [Finsterle, 1997b]. ITOUGH2 is a program for parameter estimation, sensitivity analysis, and uncertainty propagation analysis. It is based on the TOUGH2 simulator for non-isothermal multiphase flow in fractured and porous media [Preuss, 1987, 1991a]. The report ITOUGH2 User`s Guide [Finsterle, 1997a] describes the inverse modeling framework and provides the theoretical background. The report ITOUGH2 Command Reference [Finsterle, 1997b] contains the syntax of all ITOUGH2 commands. This report describes a variety of sample problems solved by ITOUGH2. Table 1.1 contains a short description of the seven sample problems discussed in this report. The TOUGH2 equation-of-state (EOS) module that needs to be linked to ITOUGH2 is also indicated. Each sample problem focuses on a few selected issues shown in Table 1.2. ITOUGH2 input features and the usage of program options are described. Furthermore, interpretations of selected inverse modeling results are given. Problem 1 is a multipart tutorial, describing basic ITOUGH2 input files for the main ITOUGH2 application modes; no interpretation of results is given. Problem 2 focuses on non-uniqueness, residual analysis, and correlation structure. Problem 3 illustrates a variety of parameter and observation types, and describes parameter selection strategies. Problem 4 compares the performance of minimization algorithms and discusses model identification. Problem 5 explains how to set up a combined inversion of steady-state and transient data. Problem 6 provides a detailed residual and error analysis. Finally, Problem 7 illustrates how the estimation of model-related parameters may help compensate for errors in that model.

  20. Visual Channel Problems.

    ERIC Educational Resources Information Center

    Mann, Philip H.; Suiter, Patricia A.

    This teacher training module classifies visual channel problems into the following four main areas: visual perception, revisualization (memory), visual-motor (eye-hand coordination), and ocular-motor tasks. Specific deficits are listed under these main headings, behaviors are given to help identify the problem, and ways to improve the condition…

  1. What Is Problem Solving?

    ERIC Educational Resources Information Center

    Martinez, Michael E.

    1998-01-01

    Many important human activities involve accomplishing goals without a script. There is no formula for true problem-solving. Heuristic, cognitive "rules of thumb" are the problem-solver's best guide. Learners should understand heuristic tools such as means-end analysis, working backwards, successive approximation, and external representation. Since…

  2. Teaching through Problem Solving

    ERIC Educational Resources Information Center

    Fi, Cos D.; Degner, Katherine M.

    2012-01-01

    Teaching through Problem Solving (TtPS) is an effective way to teach mathematics "for" understanding. It also provides students with a way to learn mathematics "with" understanding. In this article, the authors present a definition of what it means to teach through problem solving. They also describe a professional development vignette that…

  3. Inquiry and Problem Solving.

    ERIC Educational Resources Information Center

    Thorson, Annette, Ed.

    1999-01-01

    This issue of ENC Focus focuses on the topic of inquiry and problem solving. Featured articles include: (1) "Inquiry in the Everyday World of Schools" (Ronald D. Anderson); (2) "In the Cascade Reservoir Restoration Project Students Tackle Real-World Problems" (Clint Kennedy with Advanced Biology Students from Cascade High School); (3) "Project…

  4. Problems Facing Rural Schools.

    ERIC Educational Resources Information Center

    Stewart, C. E.; And Others

    Problems facing rural Scottish schools range from short term consideration of daily operation to long term consideration of organizational alternatives. Addressed specifically, such problems include consideration of: (1) liaison between a secondary school and its feeder primary schools; (2) preservice teacher training for work in small, isolated…

  5. Aircraft noise problems

    NASA Astrophysics Data System (ADS)

    1981-01-01

    The problems related to aircraft noise were studied. Physical origin (sound), human reaction (noise), quantization of noise and sound sources of aircraft noise are discussed. Noise abatement at the source, technical, fleet-political and air traffic measures are explained. The measurements and future developments are also discussed. The position of Lufthansa as regards aircraft noise problems is depicted.

  6. GREECE--SELECTED PROBLEMS.

    ERIC Educational Resources Information Center

    MARTONFFY, ANDREA PONTECORVO; AND OTHERS

    A CURRICULUM GUIDE IS PRESENTED FOR A 10-WEEK STUDY OF ANCIENT GREEK CIVILIZATION AT THE 10TH-GRADE LEVEL. TEACHING MATERIALS FOR THE UNIT INCLUDE (1) PRIMARY AND SECONDARY SOURCES DEALING WITH THE PERIOD FROM THE BRONZE AGE THROUGH THE HELLENISTIC PERIOD, (2) GEOGRAPHY PROBLEMS, AND (3) CULTURAL MODEL PROBLEM EXERCISES. THOSE CONCEPTS WITH WHICH…

  7. Problem of glider models

    NASA Technical Reports Server (NTRS)

    Lippisch, Espenlaub

    1922-01-01

    Any one endeavoring to solve the problem of soaring flight is confronted not only by structural difficulties, but also by the often far more difficult aerodynamic problem of flight properties and efficiency, which can only be determined by experimenting with the finished glider.

  8. Stabilization of Kepler's problem

    NASA Technical Reports Server (NTRS)

    Stokes, A.

    1977-01-01

    A regularization of Kepler's problem due to Moser (1970) is used to stabilize the equations of motion. In other words, a particular solution of Kepler's problem is imbedded in a Liapunov stable system. Perturbations can be introduced into the stabilized equations.

  9. Hip Problems in Infants

    MedlinePlus

    ... problems that can lead to dislocation of the hip bones. This is also called dysplasia (say: "diss-play-see-uh"). This means that ... problems later in life? Source Screening for Developmental Dysplasia of the Hip by LM French, M.D., and FR Dietz, ...

  10. Word Problem Wizardry.

    ERIC Educational Resources Information Center

    Cassidy, Jack

    1991-01-01

    Presents suggestions for teaching math word problems to elementary students. The strategies take into consideration differences between reading in math and reading in other areas. A problem-prediction game and four self-checking activities are included along with a magic password challenge. (SM)

  11. Student-Posed Problems

    NASA Astrophysics Data System (ADS)

    Harper, Kathleen A.; Etkina, Eugenia

    2002-10-01

    As part of weekly reports,1 structured journals in which students answer three standard questions each week, they respond to the prompt, If I were the instructor, what questions would I ask or problems assign to determine if my students understood the material? An initial analysis of the results shows that some student-generated problems indicate fundamental misunderstandings of basic physical concepts. A further investigation explores the relevance of the problems to the week's material, whether the problems are solvable, and the type of problems (conceptual or calculation-based) written. Also, possible links between various characteristics of the problems and conceptual achievement are being explored. The results of this study spark many more questions for further work. A summary of current findings will be presented, along with its relationship to previous work concerning problem posing.2 1Etkina, E. Weekly Reports;A Two-Way Feedback Tool, Science Education, 84, 594-605 (2000). 2Mestre, J.P., Probing Adults Conceptual Understanding and Transfer of Learning Via Problem Posing, Journal of Applied Developmental Psychology, 23, 9-50 (2002).

  12. Current Social Problem Novels.

    ERIC Educational Resources Information Center

    Kenney, Donald J.

    This review of social problem novels for young adults opens with a brief background of the genre, then lists the dominant themes of social problem fiction and nonfiction novels that have been published in the last two years, such as alcoholism, alienation, death, growing up and self-awarness, drugs, and divorce. Other themes mentioned are…

  13. Problems in baryon spectroscopy

    SciTech Connect

    Capstick, S.

    1994-04-01

    Current issues and problems in the physics of ground- and excited-state baryons are considered, and are classified into those which should be resolved by CEBAF in its present form, and those which may require CEBAF to undergo an energy upgrade to 8 GeV or more. Recent theoretical developments designed to address these problems are outlined.

  14. Modern Problems. Grade 12.

    ERIC Educational Resources Information Center

    Wilmington Public Schools, DE.

    The general purpose of the twelfth grade course is to help the student assume his role as a decision-maker in a democratic society. The nature and complexity of contemporary problems are examined using this guide to enable the student: 1) to analyze alternative solutions to these problems; 2) to develop attitudes and values appropriate to a…

  15. Problem Solving in Nursing.

    ERIC Educational Resources Information Center

    Karns, Phyllis Spear

    The relationship of educational preparation to the problem- solving performance of 55 hospital employed baccalaureate and associate degree nurses working in Wyoming hospitals was studied. Participant data were collected that might correlate with problem-solving ability: age, years of experience in nursing, years of work experience in a…

  16. Problem Solving Techniques Seminar.

    ERIC Educational Resources Information Center

    Massachusetts Career Development Inst., Springfield.

    This booklet is one of six texts from a workplace literacy curriculum designed to assist learners in facing the increased demands of the workplace. Six problem-solving techniques are developed in the booklet to assist individuals and groups in making better decisions: problem identification, data gathering, data analysis, solution analysis,…

  17. Medical problems affecting musicians.

    PubMed Central

    Potter, P. J.; Jones, I. C.

    1995-01-01

    The physical demands of performing on musical instruments can cause pain, sensory loss, and lack of coordination. Five cases illustrate common problems. Knowledge of the interaction between the technique of playing the instrument and the particular musician can help physicians diagnose and resolve problems. Images Figure 1 PMID:8680295

  18. Problem Solving in Electricity.

    ERIC Educational Resources Information Center

    Caillot, Michel; Chalouhi, Elias

    Two studies were conducted to describe how students perform direct current (D-C) circuit problems. It was hypothesized that problem solving in the electricity domain depends largely on good visual processing of the circuit diagram and that this processing depends on the ability to recognize when two or more electrical components are in series or…

  19. Problems of Advocacy.

    ERIC Educational Resources Information Center

    Ross, Robert

    This paper focusses on problems involved in adopting the newer modes of social science and professionalism. The complexities which precede these problems are recognized. It is mentioned that many recent entrants to these fields have made value commitments in their professionalism without very long detention at the portals of objectivity or…

  20. A Stochastic Employment Problem

    ERIC Educational Resources Information Center

    Wu, Teng

    2013-01-01

    The Stochastic Employment Problem(SEP) is a variation of the Stochastic Assignment Problem which analyzes the scenario that one assigns balls into boxes. Balls arrive sequentially with each one having a binary vector X = (X[subscript 1], X[subscript 2],...,X[subscript n]) attached, with the interpretation being that if X[subscript i] = 1 the ball…

  1. Some Little Night Problems.

    ERIC Educational Resources Information Center

    Cannon, Lawrence O.; Elich, Joe

    In most mathematics problem solving work, students' motivation comes from trying to please their teachers or to earn a good grade. The questions students must tackle are almost never generated by their own interest. Seven open-ended college algebra-level problems are presented in which the solution of one question suggests other related questions.…

  2. Auditory Channel Problems.

    ERIC Educational Resources Information Center

    Mann, Philip H.; Suiter, Patricia A.

    This teacher's guide contains a list of general auditory problem areas where students have the following problems: (a) inability to find or identify source of sound; (b) difficulty in discriminating sounds of words and letters; (c) difficulty with reproducing pitch, rhythm, and melody; (d) difficulty in selecting important from unimportant sounds;…

  3. Problem-Based Learning

    ERIC Educational Resources Information Center

    Allen, Deborah E.; Donham, Richard S.; Bernhardt, Stephen A.

    2011-01-01

    In problem-based learning (PBL), students working in collaborative groups learn by resolving complex, realistic problems under the guidance of faculty. There is some evidence of PBL effectiveness in medical school settings where it began, and there are numerous accounts of PBL implementation in various undergraduate contexts, replete with…

  4. Problem Solving and Intelligence.

    ERIC Educational Resources Information Center

    Resnick, Lauren B.; Glaser, Robert

    This paper argues that a major aspect of intelligence is the ability to solve problems and that careful analysis of problem-solving behavior is a means of specifying many of the psychological processes that make up intelligence. The focus is on the mechanisms involved when, in the absence of complete instruction, a person must "invent" a new…

  5. California's Water Problems.

    ERIC Educational Resources Information Center

    Wheatley, Judy; Sudman, Rita Schmidt, Ed.

    This packet of instructional materials is designed to give social science students in grades 6-9 a first-hand experience in working out solutions to real-life problems involving the management of California's water. Students work in groups on one of three problems presented in the packet: (1) the management of the Sacramento-San Joaquin Delta that…

  6. The Guderley problem revisited

    SciTech Connect

    Ramsey, Scott D; Kamm, James R; Bolstad, John H

    2009-01-01

    The self-similar converging-diverging shock wave problem introduced by Guderley in 1942 has been the source of numerous investigations since its publication. In this paper, we review the simplifications and group invariance properties that lead to a self-similar formulation of this problem from the compressible flow equations for a polytropic gas. The complete solution to the self-similar problem reduces to two coupled nonlinear eigenvalue problems: the eigenvalue of the first is the so-called similarity exponent for the converging flow, and that of the second is a trajectory multiplier for the diverging regime. We provide a clear exposition concerning the reflected shock configuration. Additionally, we introduce a new approximation for the similarity exponent, which we compare with other estimates and numerically computed values. Lastly, we use the Guderley problem as the basis of a quantitative verification analysis of a cell-centered, finite volume, Eulerian compressible flow algorithm.

  7. Generalized emissivity inverse problem.

    PubMed

    Ming, DengMing; Wen, Tao; Dai, XianXi; Dai, JiXin; Evenson, William E

    2002-04-01

    Inverse problems have recently drawn considerable attention from the physics community due to of potential widespread applications [K. Chadan and P. C. Sabatier, Inverse Problems in Quantum Scattering Theory, 2nd ed. (Springer Verlag, Berlin, 1989)]. An inverse emissivity problem that determines the emissivity g(nu) from measurements of only the total radiated power J(T) has recently been studied [Tao Wen, DengMing Ming, Xianxi Dai, Jixin Dai, and William E. Evenson, Phys. Rev. E 63, 045601(R) (2001)]. In this paper, a new type of generalized emissivity and transmissivity inverse (GETI) problem is proposed. The present problem differs from our previous work on inverse problems by allowing the unknown (emissivity) function g(nu) to be temperature dependent as well as frequency dependent. Based on published experimental information, we have developed an exact solution formula for this GETI problem. A universal function set suggested for numerical calculation is shown to be robust, making this inversion method practical and convenient for realistic calculations. PMID:12005916

  8. Problem-Solving Software

    NASA Technical Reports Server (NTRS)

    1992-01-01

    CBR Express software solves problems by adapting sorted solutions to new problems specified by a user. It is applicable to a wide range of situations. The technology was originally developed by Inference Corporation for Johnson Space Center's Advanced Software Development Workstation. The project focused on the reuse of software designs, and Inference used CBR as part of the ACCESS prototype software. The commercial CBR Express is used as a "help desk" for customer support, enabling reuse of existing information when necessary. It has been adopted by several companies, among them American Airlines, which uses it to solve reservation system software problems.

  9. Astronauts' menu problem.

    NASA Technical Reports Server (NTRS)

    Lesso, W. G.; Kenyon, E.

    1972-01-01

    Consideration of the problems involved in choosing appropriate menus for astronauts carrying out SKYLAB missions lasting up to eight weeks. The problem of planning balanced menus on the basis of prepackaged food items within limitations on the intake of calories, protein, and certain elements is noted, as well as a number of other restrictions of both physical and arbitrary nature. The tailoring of a set of menus for each astronaut on the basis of subjective rankings of each food by the astronaut in terms of a 'measure of pleasure' is described, and a computer solution to this problem by means of a mixed integer programming code is presented.

  10. Diabetic Eye Problems

    MedlinePlus

    ... too high. Over time, this can damage your eyes. The most common problem is diabetic retinopathy. It ... light-sensitive tissue at the back of your eye. You need a healthy retina to see clearly. ...

  11. Preventing Diabetes Problems

    MedlinePlus

    ... the biggest health problem for people with diabetes. LDL cholesterol. LDL cholesterol is known as the bad cholesterol because it ... you often eat foods that are high in LDL cholesterol high cholesterol runs in your family HDL cholesterol. ...

  12. NAEP Note: Problem Solving.

    ERIC Educational Resources Information Center

    Carpenter, Thomas P.; And Others

    1980-01-01

    Student weaknesses on problem-solving portions of the NAEP mathematics assessment are discussed using Polya's heuristics as a framework. Recommendations for classroom instruction are discussed. (MP) Aspect of National Assessment (NAEP) dealt with in this document: Results (Interpretation).

  13. [Oral problems in divers].

    PubMed

    Scheper, W A; Lobbezoo, F; Eijkman, M A J

    2005-05-01

    Divers can have several oral problems. Firstly, problems caused by pressure changes. These are barodontalgia and odontocrexis. Barodontalgia is toothache by barotrauma. Odontocrexis is restorations coming lose or breaking or tooth fractures by expansion of air beneath restorations. Other problems can occur by cements used to fix casted restorations, by inflammations in the orofacial region, and by not yet fully healed oral wounds. Secondly, there are problems related to the diver's mouthpiece. To keep the mouthpiece in place, the mandible has to be forced in a forward position. Holding this position often and for long periods of time, may develop or aggravate temporomandibular dysfunction. Insufficient fit of the mouthpiece may induce oral mucosal lesions. Therefore, it is recommended to produce individual diver mouthpieces. It is also recommended to produce individual diver mouthpieces for complete dentures wearing divers and for divers with fixed orthodontic appliances. PMID:15932043

  14. Enuresis: A Social Problem.

    ERIC Educational Resources Information Center

    McDonald, James E.

    1978-01-01

    Several theories and treatments of enuresis are described. The authors conclude that enuresis is a social problem (perhaps due to maturational lag, developmental delay or faulty learning) which requires teacher and parental tolerance and understanding. (SE)

  15. Solving Tommy's Writing Problems.

    ERIC Educational Resources Information Center

    Burdman, Debra

    1986-01-01

    The article describes an approach by which word processing helps to solve some of the writing problems of learning disabled students. Aspects considered include prewriting, drafting, revising, and completing the story. (CL)

  16. Types of Learning Problems

    MedlinePlus

    ... words, whereas motor clumsiness or defective visual-spatial perception affects only handwriting, not spelling. Dyscalculia Dyscalculia is ... related to memory, problem solving skills, logical thought, perception and attention span. Like parents of other adolescents ...

  17. Women and sexual problems

    MedlinePlus

    ... problems may include: Getting older: a woman's sex drive often decreases with age. This is normal. It ... pressure, depression, and chemotherapy can decrease your sex drive or make it hard to have an orgasm. ...

  18. The Pesticide Problem.

    ERIC Educational Resources Information Center

    Bosch, Van Den Robert

    1979-01-01

    Contains a discussion of insects' ability to survive, of the development of pesticides and the introduction of DDT, of the problems of pesticide use and resistance to insecticides, and of the advantages of integrated pest control. (BB)

  19. Overcoming breastfeeding problems

    MedlinePlus

    Plugged milk ducts; Nipple soreness when breastfeeding; Breastfeeding - overcoming problems; Let-down reflex ... Breastfeeding (nursing) your baby can be a good experience for both the mother and the baby. It ...

  20. Down Syndrome: Eye Problems

    MedlinePlus

    ... life expectancy. Do children with Down syndrome have eye problems? Individuals with Down syndrome are at increased ... When should children with Down syndrome receive an eye exam? The American Academy of Pediatrics recommends that ...

  1. Rotator cuff problems

    MedlinePlus

    ... days, such as in painting and carpentry Poor posture over many years Aging Rotator cuff tears TEARS ... also help prevent rotator cuff problems. Practice good posture to keep your rotator cuff tendons and muscles ...

  2. Puzzles, Pastimes, Problems.

    ERIC Educational Resources Information Center

    Eperson, D. B.

    1985-01-01

    Presents six mathematical problems (with answers) which focus on: (1) chess moves; (2) patterned numbers; (3) quadratics with rational roots; (4) number puzzles; (5) Euclidean geometry; and (6) Carrollian word puzzles. (JN)

  3. STAGS Example Problems Manual

    NASA Technical Reports Server (NTRS)

    Knight, Norman F., Jr.; Rankin, Charles C.

    2006-01-01

    This document summarizes the STructural Analysis of General Shells (STAGS) development effort, STAGS performance for selected demonstration problems, and STAGS application problems illustrating selected advanced features available in the STAGS Version 5.0. Each problem is discussed including selected background information and reference solutions when available. The modeling and solution approach for each problem is described and illustrated. Numerical results are presented and compared with reference solutions, test data, and/or results obtained from mesh refinement studies. These solutions provide an indication of the overall capabilities of the STAGS nonlinear finite element analysis tool and provide users with representative cases, including input files, to explore these capabilities that may then be tailored to other applications.

  4. The cosmological constant problem

    SciTech Connect

    Dolgov, A.D.

    1989-05-01

    A review of the cosmological term problem is presented. Baby universe model and the compensating field model are discussed. The importance of more accurate data on the Hubble constant and the Universe age is stressed. 18 refs.

  5. Problems with Taste

    MedlinePlus

    ... less frequently than problems with smell. How Our Sense of Taste Works Our sense of taste, along ... may start to lose taste buds. Five Taste Sensations We can experience five basic taste sensations: sweet, ...

  6. Mouth Problems and HIV

    MedlinePlus

    ... orientation. This information is for people who have mouth (oral) problems related to HIV infection. It explains ... look like. It also describes where in the mouth they occur and how they are treated. They ...

  7. The Problems of WARC.

    ERIC Educational Resources Information Center

    Pool, Ithiel de Sola

    1979-01-01

    Presents several anticipated problems to be handled at the 1979 World Administrative Conference including an orbital allocation plan, political and ideological issues concerning sovereignty and prior consent, spectrum assignments, and sharing of TV frequencies with land mobile radio. (JMF)

  8. The problem of pain.

    PubMed

    Nicholson, Keith; Martelli, Michael F

    2004-01-01

    Pain problems, especially posttraumatic headache, are very common following head trauma. Pain may be the most significant problem, more disabling than any brain or other injuries, and interfering with aspects of cognition or other function. However, posttraumatic headache and most other chronic posttraumatic pain problems remain poorly understood. This article reviews fundamental issues that should be considered in understanding the nature of chronic pain including the distinction between acute and chronic pain; neurobiological distinctions between the lateral and medial pain system; nociceptive versus neuropathic or other central pain; sensitization effects; the widely accepted view of chronic pain as a multidimensional subjective experience involving sensory, motivational-affective and cognitive-behavioral components; the problem of mind-body dualism; the role of psychosocial factors in the onset, maintenance, exacerbation or severity of pain; plus issues of response bias and malingering. PMID:14732827

  9. Our Accountability Problems

    ERIC Educational Resources Information Center

    Cunningham, Luvern L.

    1969-01-01

    Evaluation of school administrators to determine whether they are truly performing their functions adequately has presented a problem of long standing since most administrators find excuses to avoid appraisal of their performance. (CK)

  10. Menstrual Cycle Problems

    MedlinePlus

    ... or legs? Yes Your symptoms may be from FIBROIDS, noncancerous tumors of the uterus. See your doctor. ... premature MENOPAUSE. Irregular periods may be due to FIBROIDS, HORMONE PROBLEMS, or other medical conditions. See your ...

  11. The Problem of Heroin

    ERIC Educational Resources Information Center

    Wilson, James Q.; And Others

    1972-01-01

    Argues that most of the underlying assumptions of presently recommended solutions to the problem of heroin addiction are unreasonable, unwarranted, or at least open to more than one interpretation. (DM)

  12. Overcoming breastfeeding problems

    MedlinePlus

    ... position Reducing distractions during nursing, performing a gentle massage, and applying heat to the breast Nursing often ( ... JL, et al, eds. Obstetrics: Normal and Problem Pregnancies . 6th ed. Philadelphia, PA: Elsevier Saunders; 2012:chap ...

  13. Network problem threshold

    NASA Technical Reports Server (NTRS)

    Gejji, Raghvendra, R.

    1992-01-01

    Network transmission errors such as collisions, CRC errors, misalignment, etc. are statistical in nature. Although errors can vary randomly, a high level of errors does indicate specific network problems, e.g. equipment failure. In this project, we have studied the random nature of collisions theoretically as well as by gathering statistics, and established a numerical threshold above which a network problem is indicated with high probability.

  14. The Sahel problem.

    PubMed

    Sinn, H

    1988-01-01

    Problems concerning the provision of development aid to the Sahel region of Africa are discussed. The author argues that the population already exceeds the area's carrying capacity, and that the provision of direct aid to the region will only encourage further in-migration and exacerbate the problem. He argues that aid should be provided to neighboring areas with the capacity to support larger populations, which will eventually improve the standard of living of the whole region. PMID:12315680

  15. Smoothers for Optimization Problems

    NASA Technical Reports Server (NTRS)

    Arian, Eyal; Ta'asan, Shlomo

    1996-01-01

    We present a multigrid one-shot algorithm, and a smoothing analysis, for the numerical solution of optimal control problems which are governed by an elliptic PDE. The analysis provides a simple tool to determine a smoothing minimization process which is essential for multigrid application. Numerical results include optimal control of boundary data using different discretization schemes and an optimal shape design problem in 2D with Dirichlet boundary conditions.

  16. The basketball problem

    NASA Astrophysics Data System (ADS)

    Schröer, H.

    In basketball there is the problem of hitting a basket at a determined distance and a determined height. The quantities that can be changed during the inclined throw are the initial velocity and the angle of throw. At first we neglect the air resistance. Then we treat the same problem in a medium (liquid, gas) with constant density. We obtain two differential equations. Then we view special cases of the retarding force. There is an english and a german edition.

  17. Living with Bowel Control Problems

    MedlinePlus

    ... Home Living with Bowel Control Problems Resources Bowel Control Awareness Campaign Home Resources for Health Care Providers ... Living with Bowel Control Problems Living with Bowel Control Problems Living with a bowel control problem can ...

  18. Measure recognition problem.

    PubMed

    Dzamonja, Mirna

    2006-12-15

    This is a paper in mathematics, specifically in set theory. On the example of the measure recognition problem (MRP), the paper highlights the phenomenon of the utility of a multidisciplinary mathematical approach to a single mathematical problem, in particular, the value of a set-theoretic analysis. MRP asks if for a given Boolean algebra, B, and a property, Phi, of measures, one can recognize by purely combinatorial means if B supports a strictly positive measure with property Phi. The most famous instance of this problem is MRP (countable additivity), and in the first part of the paper, we survey the known results on this and some other problems. We show how these results naturally lead to asking about two other specific instances of the problem MRP, namely MRP (non-atomic) and MRP (separable). Then, we show how our recent work gives an easy solution to the former of these problems and some partial information about the latter. The long-term goal of this line of research is to obtain a structure theory of Boolean algebras that support a finitely additive strictly positive measure, along the lines of Maharam theorem, which gives such a structure theorem for measure algebras. PMID:17090453

  19. Exceptional cases of Terai's conjecture on Diophantine equations

    NASA Astrophysics Data System (ADS)

    Miyazaki, Takafumi

    2011-09-01

    Let p,q,r be positive integers with p,q,r≥2, and let a,b,c be relatively prime positive integers with ap+bq = cr. Terai conjectured that (apart from a handful of known exceptions) the only solution of the equation ax+by = cz in positive integers x,y,z is (x,y,z) = (p,q,r). In this article, we consider the case q = r = 2 and give some results related to exceptional cases.

  20. The Exponential Diophantine Equation 2x + by = cz

    PubMed Central

    Yu, Yahui; Li, Xiaoxue

    2014-01-01

    Let b and c be fixed coprime odd positive integers with min{b, c} > 1. In this paper, a classification of all positive integer solutions (x, y, z) of the equation 2x + by = cz is given. Further, by an elementary approach, we prove that if c = b + 2, then the equation has only the positive integer solution (x, y, z) = (1,1, 1), except for (b, x, y, z) = (89,13,1, 2) and (2r − 1, r + 2,2, 2), where r is a positive integer with r ≥ 2. PMID:24959613

  1. Bicriteria network design problems

    SciTech Connect

    Marathe, M.V.; Ravi, R.; Sundaram, R.; Ravi, S.S.; Rosenkrantz, D.J.; Hunt, H.B. III

    1997-11-20

    The authors study a general class of bicriteria network design problems. A generic problem in this class is as follows: Given an undirected graph and two minimization objectives (under different cost functions), with a budget specified on the first, find a subgraph from a given subgraph class that minimizes the second objective subject to the budget on the first. They consider three different criteria -- the total edge cost, the diameter and the maximum degree of the network. Here, they present the first polynomial-time approximation algorithms for a large class of bicriteria network design problems for the above mentioned criteria. The following general types of results are presented. First, they develop a framework for bicriteria problems and their approximations. Second, when the two criteria are the same they present a black box parametric search technique. This black box takes in as input an (approximation) algorithm for the criterion situation and generates an approximation algorithm for the bicriteria case with only a constant factor loss in the performance guarantee. Third, when the two criteria are the diameter and the total edge costs they use a cluster based approach to devise approximation algorithms. The solutions violate both the criteria by a logarithmic factor. Finally, for the class of treewidth-bounded graphs, they provide pseudopolynomial-time algorithms for a number of bicriteria problems using dynamic programming. The authors show how these pseudopolynomial-time algorithms can be converted to fully polynomial-time approximation schemes using a scaling technique.

  2. Colored Traveling Salesman Problem.

    PubMed

    Li, Jun; Zhou, MengChu; Sun, Qirui; Dai, Xianzhong; Yu, Xiaolong

    2015-11-01

    The multiple traveling salesman problem (MTSP) is an important combinatorial optimization problem. It has been widely and successfully applied to the practical cases in which multiple traveling individuals (salesmen) share the common workspace (city set). However, it cannot represent some application problems where multiple traveling individuals not only have their own exclusive tasks but also share a group of tasks with each other. This work proposes a new MTSP called colored traveling salesman problem (CTSP) for handling such cases. Two types of city groups are defined, i.e., each group of exclusive cities of a single color for a salesman to visit and a group of shared cities of multiple colors allowing all salesmen to visit. Evidences show that CTSP is NP-hard and a multidepot MTSP and multiple single traveling salesman problems are its special cases. We present a genetic algorithm (GA) with dual-chromosome coding for CTSP and analyze the corresponding solution space. Then, GA is improved by incorporating greedy, hill-climbing (HC), and simulated annealing (SA) operations to achieve better performance. By experiments, the limitation of the exact solution method is revealed and the performance of the presented GAs is compared. The results suggest that SAGA can achieve the best quality of solutions and HCGA should be the choice making good tradeoff between the solution quality and computing time. PMID:25494521

  3. The Guderley problem revisited

    NASA Astrophysics Data System (ADS)

    Ramsey, Scott D.; Kamm, James R.; Bolstad, John H.

    2012-02-01

    The self-similar converging-diverging shock wave problem introduced by Guderley in 1942 has been the source of considerable mathematical and physical interest. We investigate a novel application of the Guderley solution as a unique and challenging code verification test problem for compressible flow algorithms; this effort requires a unified understanding of the problem's mathematical and computational subtleties. Hence, we review the simplifications and group invariance properties that reduce the compressible flow equations for a polytropic gas to two coupled nonlinear eigenvalue problems: the first for the similarity exponent in the converging regime, and the second for a trajectory multiplier in the diverging regime. The information we provide, together with previously published material, gives a complete description of the computational steps required to construct a semi-analytic Guderley solution. We employ the problem in a quantitative code verification analysis of a cell-centred, finite volume, Eulerian compressible flow algorithm. Lastly, in appended material, we introduce a new approximation for the similarity exponent, which may prove useful in the future construction of certain semi-analytic Guderley solutions.

  4. Preventing remediation problems

    SciTech Connect

    Fleming, W.H.

    1994-12-31

    Remediation, the design and construction of a remedy, typically represents the most significant portion of the cleanup process. The cost may be 5 to 10 times the cost of earlier investigation and feasibility efforts. Furthermore, the risks associated with remediation activities and their ability to meet ultimate cleanup goals and objectives are far greater than those associated with earlier efforts. Often times there are unrealistic expectations interjected throughout the design and construction process in the remediation field. The simple fact that most problems are buried, and one cannot see all that is below the ground surface provides sufficient uncertainty to result in problems. There are three key points during the remediation process which provide opportunities to prevent and avoid problems. These are: (1) during design; (2) during procurement and contracting; and (3) during construction. This paper examines actions which the author has found or believes will assist in providing a formula for success.

  5. Revisiting Lambert's problem

    NASA Astrophysics Data System (ADS)

    Izzo, Dario

    2015-01-01

    The orbital boundary value problem, also known as Lambert problem, is revisited. Building upon Lancaster and Blanchard approach, new relations are revealed and a new variable representing all problem classes, under L-similarity, is used to express the time of flight equation. In the new variable, the time of flight curves have two oblique asymptotes and they mostly appear to be conveniently approximated by piecewise continuous lines. We use and invert such a simple approximation to provide an efficient initial guess to an Householder iterative method that is then able to converge, for the single revolution case, in only two iterations. The resulting algorithm is compared, for single and multiple revolutions, to Gooding's procedure revealing to be numerically as accurate, while having a significantly smaller computational complexity.

  6. VERIFICATION TEST PROBLEMS

    SciTech Connect

    Moran, B

    2007-08-08

    We present analytic solutions to two test problems that can be used to check the hydrodynamic implementation in computer codes designed to calculate the propagation of shocks in spherically convergent geometry. Our analysis is restricted to fluid materials with constant bulk modulus. In the first problem we present the exact initial acceleration and pressure gradient at the outer surface of a sphere subjected to an exponentially decaying pressure of the form P(t) = P{sub 0}e{sup -at}. We show that finely-zoned hydro-code simulations are in good agreement with our analytic solution. In the second problem we discuss the implosions of incompressible spherical fluid shells and we present the radial pressure profile across the shell thickness. We also discuss a semi-analytic solution to the time-evolution of a nearly spherical shell with arbitrary but small initial 3-dimensional (3-D) perturbations on its inner and outer surfaces.

  7. Global geochemical problems

    NASA Technical Reports Server (NTRS)

    Harriss, R. C.

    1980-01-01

    Application of remote sensing techniques to the solution of geochemical problems is considered with emphasis on the 'carbon-cycle'. The problem of carbon dioxide sinks and the areal extent of coral reefs are treated. In order to assess the problems cited it is suggested that remote sensing techniques be utilized to: (1)monitor globally the carbonate and bicarbonate concentrations in surface waters of the world ocean; (2)monitor the freshwater and oceanic biomass and associated dissolved organic carbon; (3) inventory the coral reef areas and types and the associated oceanographic climatic conditions; and (4)measure the heavy metal fluxes from forested and vegetated areas, from volcanos, from different types of crustal rocks, from soils, and from sea surfaces.

  8. The Sedov Test Problem

    SciTech Connect

    Fung, Jimmy; Masser, Thomas; Morgan, Nathaniel R.

    2012-06-25

    The Sedov test is classically defined as a point blast problem. The Sedov problem has led us to advances in algorithms and in their understanding. Vorticity generation can be physical or numerical. Both play a role in Sedov calculations. The RAGE code (Eulerian) resolves the shock well, but produces vorticity. The source definition matters. For the FLAG code (Lagrange), CCH is superior to SGH by avoiding spurious vorticity generation. FLAG SGH currently has a number of options that improve results over traditional settings. Vorticity production, not shock capture, has driven the Sedov work. We are pursuing treatments with respect to the hydro discretization as well as to artificial viscosity.

  9. Problems of space chemistry

    NASA Astrophysics Data System (ADS)

    Voitkevich, Georgii V.

    The main problems of space chemistry are examined, including the origin and abundance of chemical elements, their migration to different regions of the universe, the formation of the chemical composition of cosmic bodies, and the chemical evolution of the solar system and the origin of life. Based on current astrophysical and space-chemical data, the main stages of the evolution of matter from the beginning of universe expansion to the formation of the solar system are described. The problem of the origin of life is examined in the light of space-chemical data on the formation of high-molecular compounds before the formation of the planets.

  10. The Urinal Problem

    NASA Astrophysics Data System (ADS)

    Kranakis, Evangelos; Krizanc, Danny

    A man walks into a men's room and observes n empty urinals. Which urinal should he pick so as to maximize his chances of maintaining privacy, i.e., minimize the chance that someone will occupy a urinal beside him? In this paper, we attempt to answer this question under a variety of models for standard men's room behavior. Our results suggest that for the most part one should probably choose the urinal furthest from the door (with some interesting exceptions). We also suggest a number of variations on the problem that lead to many open problems.

  11. Assessing the Quality of Problems in Problem-Based Learning

    ERIC Educational Resources Information Center

    Sockalingam, Nachamma; Rotgans, Jerome; Schmidt, Henk

    2012-01-01

    This study evaluated the construct validity and reliability of a newly devised 32-item problem quality rating scale intended to measure the quality of problems in problem-based learning. The rating scale measured the following five characteristics of problems: the extent to which the problem (1) leads to learning objectives, (2) is familiar, (3)…

  12. and Internalizing Behavior Problems

    ERIC Educational Resources Information Center

    Hofer, Claire; Eisenberg, Nancy; Spinrad, Tracy L.; Morris, Amanda S.; Gershoff, Elizabeth; Valiente, Carlos; Kupfer, Anne; Eggum, Natalie D.

    2013-01-01

    Stability and change in mother-adolescent conflict reactions (CRs) and the prediction of CRs from adolescents' earlier behavior problems (and vice versa) were examined with 131 mothers and their adolescents (63 boys). Dyads engaged in a 6-min conflict discussion twice, 2 years apart ["M" age was 13 at Time 1 (T1)]. Non-verbal expressive and verbal…

  13. Problem Behaviors as Operants

    ERIC Educational Resources Information Center

    Hoyer, William J.; And Others

    1975-01-01

    Many of the clinically disabling behaviors of elderly persons may be viewed as operants. Research bearing on the efficacy of operant techniques for programming individualized, group based, and ward-wide therapeutic intervention is reviewed. Suggests the operant view is useful for conceptualizing and treating many problem behaviors of elderly…

  14. The Eight Queens Problem.

    ERIC Educational Resources Information Center

    Olson, Alton T.

    1993-01-01

    Presents a series of solution methods to the Eight Queens Problem of placing eight queens on a chess board so that no one queen can capture another. Solution methods progress from empirical approaches to the use of computer algorithms. Geometric transformations are used to find other solutions. (MDH)

  15. [Problem Solving Activities.

    ERIC Educational Resources Information Center

    Wisconsin Univ. - Stout, Menomonie. Center for Vocational, Technical and Adult Education.

    The teacher directed problem solving activities package contains 17 units: Future Community Design, Let's Build an Elevator, Let's Construct a Catapult, Let's Design a Recreational Game, Let's Make a Hand Fishing Reel, Let's Make a Wall Hanging, Let's Make a Yo-Yo, Marooned in the Past, Metrication, Mousetrap Vehicles, The Multi System…

  16. Bicriteria network design problems

    SciTech Connect

    Marathe, M.V.; Ravi, R.; Sundaram, R.; Ravi, S.S.; Rosenkrantz, D.J.; Hunt, H.B. III

    1995-05-01

    We study several bicriteria network design problems phrased as follows: given an indirected graph and two minimization objectives with a budget specified on one objective, find a subgraph satisfying certain connectivity requirements that minimizes the second objective subject to the budget on the first. First, we develop a formalism for bicriteria problems and their approximations. Secondly, we use a simple parametric search technique to provide bicriteria approximation algorithms for problems with two similar criteria, where both criteria are the same measure (such as the diameter or the total cost of a tree) but differ only in the cost function under which the measure is computed. Thirdly, we present an (O(log n), O(log n))-approximation algorithm for finding a diameter-constrained minimum cost spanning tree of an undirected graph on n nodes. Finally, for the class of treewidth-bounded graphs, we provide pseudopolynomial-time algorithms for a number of bicriteria problems using dynamic programming. These pseudopolynomial-time algorithms can be converted to fully polynomial-time approximation schemes using a scaling technique.

  17. Unfolding a Problem

    ERIC Educational Resources Information Center

    Currier, Sarah Cox

    2015-01-01

    In this article, Sarah Currier, a math specialist at Elizabeth Hall International School in Minnesota, describes how she used origami in a deliberate manner to teach content. She shares how she uses paper folding to teach mathematical concepts, reinforce vocabulary, and as a problem-solving model. She also offers ideas for using origami in other…

  18. Solving Problems in Genetics

    ERIC Educational Resources Information Center

    Aznar, Mercedes Martinez; Orcajo, Teresa Ibanez

    2005-01-01

    A teaching unit on genetics and human inheritance using problem-solving methodology was undertaken with fourth-level Spanish Secondary Education students (15 year olds). The goal was to study certain aspects of the students' learning process (concepts, procedures and attitude) when using this methodology in the school environment. The change…

  19. Chemical Reaction Problem Solving.

    ERIC Educational Resources Information Center

    Veal, William

    1999-01-01

    Discusses the role of chemical-equation problem solving in helping students predict reaction products. Methods for helping students learn this process must be taught to students and future teachers by using pedagogical skills within the content of chemistry. Emphasizes that solving chemical reactions should involve creative cognition where…

  20. Problem Solving Using Calculators.

    ERIC Educational Resources Information Center

    Billings, Karen; Moursund, David

    1978-01-01

    The first part in the serialized version of a book on the use of calculators for problem solving is presented. It contains prefaces for teachers and students and a chapter on getting started which includes topics such as symmetries, operations, powers, and chaining. (MP)

  1. Solving Common Mathematical Problems

    NASA Technical Reports Server (NTRS)

    Luz, Paul L.

    2005-01-01

    Mathematical Solutions Toolset is a collection of five software programs that rapidly solve some common mathematical problems. The programs consist of a set of Microsoft Excel worksheets. The programs provide for entry of input data and display of output data in a user-friendly, menu-driven format, and for automatic execution once the input data has been entered.

  2. Learning through Problem Solving.

    ERIC Educational Resources Information Center

    Murray, Hanlie; Olivier, Alwyn; Human, Piet

    After conducting several studies on young students' understanding of particular concepts before, during, and after instruction, this paper focuses on the two small scale and several informal teaching experiments based on the idea that the teacher should pose problems to students for which they do not yet have a routine solution method available,…

  3. Hearing Problems in Children

    MedlinePlus

    ... age 6 months. That's because children start learning speech and language long before they talk. Hearing problems can be temporary or permanent. Sometimes, ear infections, injuries or diseases affect hearing. If your child does not hear well, get help. NIH: National ...

  4. Tackling a Local Problem.

    ERIC Educational Resources Information Center

    Cook, Martin

    1995-01-01

    Students studying water as a class project were concerned by levels of pollution at a nearby river and the local beach. They identified three environmental problems for research including sewage discharge, beach litter, and quality of swimming water. Research consisted of field trips which allowed for opportunities to improve skills in collecting…

  5. Universal Design Problem Solving

    ERIC Educational Resources Information Center

    Sterling, Mary C.

    2004-01-01

    Universal design is made up of four elements: accessibility, adaptability, aesthetics, and affordability. This article addresses the concept of universal design problem solving through experiential learning for an interior design studio course in postsecondary education. Students' experiences with clients over age 55 promoted an understanding of…

  6. Correct Problems, Desperate Solutions.

    ERIC Educational Resources Information Center

    Donohue, William A.

    1996-01-01

    Argues that the social problems confronting America have been bombarded with ill-conceived and unsuccessful social policy largely driven by fear. Explains that parental licensing is a draconian and unworkable solution. Vouchers for indigent youth to attend Catholic schools, developing after-school and summer programs, and reforming welfare are…

  7. Problems in Graduate Education...

    ERIC Educational Resources Information Center

    Whaley, W. Gordon

    The Commission on Graduate Education of the National Association of State Universities and Land Grant Colleges has assembled in this booklet the nature of the fundamental problems of graduate education accompanied by recommendations for action. Nine areas of concern include redesigning graduate education for the twentieth century, distinguishing…

  8. Dermatologic problems of musicians.

    PubMed

    Rimmer, S; Spielvogel, R L

    1990-04-01

    The unique occupational dermatologic disorders of musicians are reviewed and compiled to provide the clinician with a reference list. Our results were obtained by a survey of 24 members of a professional symphony orchestra. The results of the survey revealed a significant incidence of occupationally related skin problems in musicians. PMID:2138638

  9. Problems of Excess Capacity

    NASA Technical Reports Server (NTRS)

    Douglas, G.

    1972-01-01

    The problems of excess capacity in the airline industry are discussed with focus on the following topics: load factors; fair rate of return on investment; service-quality rivalry among airlines; pricing (fare) policies; aircraft production; and the impacts of excess capacity on operating costs. Also included is a discussion of the interrelationships among these topics.

  10. "Righting" the Writing Problem.

    ERIC Educational Resources Information Center

    Shaughnessy, Michael F.; Eastham, Nicholas

    The problem of college students' writing skills or lack thereof is generally agreed upon in academia. One cause is the inordinate amount of multiple choice/true false/fill in the blank type of tests that students take in high school and college. Not only is there is a dearth of actual classes in writing available, few students recognize the need…

  11. Transformation Problem Solving Abilities.

    ERIC Educational Resources Information Center

    Harmel, Sarah Jane

    The relationship between transformation problem performance and Guilford Structure of Intellect (SI) abilities is explored. During two group sessions 42 females and 35 males, age 18-39, were administered 12 Guilford SI tests exemplifying all five symbolic content (numeric) operations, and three contents in the divergent production area. Logical…

  12. The Problem of Consciousness.

    ERIC Educational Resources Information Center

    Crick, Francis; Koch, Christof

    1992-01-01

    Discusses approaches to the problem presented in understanding consciousness as a yet undiscovered process of interacting neuron activity. Presents the historical context of research in the area of human awareness and identifies research necessary to scientifically explain how the brain relates to the mind. (MCO)

  13. Convention Problems - 1787.

    ERIC Educational Resources Information Center

    Hanson, Deroy L.

    Designed to motivate eighth-grade civics students in the study of the United States Constitution, this game is intended to simulate the basic problems faced by the delegates to the Philadelphia Convention of 1787. The four parts of the game introduce the governmental concepts of the bicameral legislature, the executive branch, the judicial branch,…

  14. Children Solve Problems.

    ERIC Educational Resources Information Center

    De Bono, Edward

    A group of children were presented with several tasks, including the invention of a sleep machine and a machine to weigh elephants. The tasks were chosen to involve the children in coping with problems of a distinct character. A study of the children's drawings and interpretations shows that children's thinking ability is not very different from…

  15. Thermodynamics with Design Problems.

    ERIC Educational Resources Information Center

    Cilento, E. V.; Sears, J. T.

    1983-01-01

    Discusses how basic thermodynamics concepts are integrated with design problems. Includes course goals, instructional strategies, and major advantages/disadvantages of the integrated design approach. Advantages include making subject more concrete, emphasizing interrelation of variables, and reinforcing concepts by use in design analysis; whereas…

  16. The Classical Cake Problem

    ERIC Educational Resources Information Center

    Nelson, Norman N.; Fisch, Forest N.

    1973-01-01

    Discussed are techniques of presentation and solution of the Classical Cake Problem. A frosted cake with a square base is to be cut into n pieces with the volume of cake and frosting the same for each piece. Needed are minimal geometric concepts and the formula for the volume of a prism. (JP)

  17. Environmental Health Problems.

    ERIC Educational Resources Information Center

    Environmental Health Service (DHEW/PHS), Rockville, MD.

    Aimed at a society which is forced to make decisions relative to their total environment, this pamphlet discusses a few of the problems associated with restoring and maintaining an environmental relationship conducive to the health and well-being of man. The topics covered include: air pollution, noise, solid waste, the urban environment, drinking…

  18. Dynamical impurity problems

    SciTech Connect

    Emery, V.J.; Kivelson, S.A.

    1993-12-31

    In the past few years there has been a resurgence of interest in dynamical impurity problems, as a result of developments in the theory of correlated electron systems. The general dynamical impurity problem is a set of conduction electrons interacting with an impurity which has internal degrees of freedom. The simplest and earliest example, the Kondo problem, has attracted interest since the mid-sixties not only because of its physical importance but also as an example of a model displaying logarithmic divergences order by order in perturbation theory. It provided one of the earliest applications of the renormalization group method, which is designed to deal with just such a situation. As we shall see, the antiferromagnetic Kondo model is controlled by a strong-coupling fixed point, and the essence of the renormalization group solution is to carry out the global renormalization numerically starting from the original (weak-coupling) Hamiltonian. In these lectures, we shall describe an alternative route in which we identify an exactly solvable model which renormalizes to the same fixed point as the original dynamical impurity problem. This approach is akin to determining the critical behavior at a second order phase transition point by solving any model in a given universality class.

  19. Problem Solving with Patents

    ERIC Educational Resources Information Center

    Moore, Jerilou; Sumrall, William J.

    2008-01-01

    Exploring our patent system is a great way to engage students in creative problem solving. As a result, the authors designed a teaching unit that uses the study of patents to explore one avenue in which scientists and engineers do science. Specifically, through the development of an idea, students learn how science and technology are connected.…

  20. The Pyramid Problem.

    ERIC Educational Resources Information Center

    Onions, Chris

    1991-01-01

    Presented are the solutions generated by a fifth grade class to the problem of finding the sum of the number of blocks in a pyramid with a bottom layer containing seven blocks. Three methods were recorded: a levels method, a columns method, and a vertical slice method. (MDH)

  1. Solving Problems through Circles

    ERIC Educational Resources Information Center

    Grahamslaw, Laura; Henson, Lisa H.

    2015-01-01

    Several problem-solving interventions that utilise a "circle" approach have been applied within the field of educational psychology, for example, Circle Time, Circle of Friends, Sharing Circles, Circle of Adults and Solution Circles. This research explored two interventions, Solution Circles and Circle of Adults, and used thematic…

  2. Symmetries of Spectral Problems

    NASA Astrophysics Data System (ADS)

    Shabat, A.

    Deriving abelian KdV and NLS hierarchies, we describe non-abelian symmetries and "pre-Lax" elementary approach to Lax pairs. Discrete symmetries of spectral problems are considered in Sect. 4.2. Here we prove Darboux classical theorem and discuss a modern theory of dressing chains.

  3. Human Population Problems

    ERIC Educational Resources Information Center

    Emmel, Thomas C.; Sligh, Michael M.

    1970-01-01

    Asserts that overpopulation is the most pressing world problem. Topics discussed include population control in primitive societies, population growth and control in modern societies, methods of motivational population control, consequences of no population control, and mass famines during the 1970's in underdeveloped countries. Cities 33…

  4. The Problem of "Noise"

    ERIC Educational Resources Information Center

    Vagianos, Louis

    1972-01-01

    The library problem consists of equal parts of external and internal noise. The external noise consists of the volume of publication. The internal noise can be characterized by the present and continuing brouhaha concerning reform of library education. Scientists frankly regard librarians as impediments to information. (Author/NH)

  5. Circumference and Problem Solving.

    ERIC Educational Resources Information Center

    Blackburn, Katie; White, David

    The concept of pi is one of great importance to all developed civilization and one that can be explored and mastered by elementary students through an inductive and problem-solving approach. Such an approach is outlined and discussed. The approach involves the following biblical quotation: "And he made a moltin sea ten cubits from one brim to the…

  6. Health Problems in Pregnancy

    MedlinePlus

    Every pregnancy has some risk of problems. The causes can be conditions you already have or conditions you develop. They also include being pregnant with ... health care provider about how to minimize your risk before you get pregnant. Once you are pregnant, ...

  7. LEXICOGRAPHICAL PROBLEMS IN PASHTO.

    ERIC Educational Resources Information Center

    CHAVARRIS-AGUILAR, O.L.; PENZL, HERBERT

    PROBLEMS IN DEVELOPING SUITABLE DICTIONARIES OF PASHTO WERE REPORTED. PASHTO WAS DESCRIBED AS A MEMBER OF THE IRANIAN BRANCH OF THE INDO-EUROPEAN LANGUAGES SPOKEN IN EASTERN AND SOUTHERN AFGHANISTAN AND IN NORTHEASTERN PAKISTAN. FIVE TOPICS DEALING WITH THE PASHTO LANGUAGE WERE DISCUSSED--(1) STATISTICS, (2) WRITTEN CORPUS AND LEXICAL STUDIES, (3)…

  8. A Multifaceted Minimization Problem.

    ERIC Educational Resources Information Center

    Pomeranz, Janet Bellcourt

    1983-01-01

    The problem "Given three planar points, find a point such that the sum of the distances from that point to the three points is a minimum" is discussed from several points of view. A solution that uses only calculus and geometry is examined in detail. (MNS)

  9. Cognitive Problems (Disorientation, Perception, Attention, Learning and Problem-Solving)

    MedlinePlus

    ... SOMEONE WITH EMOTIONAL & BEHAVIORAL NEEDS Cognitive Problems (Disorientation, Perception, Attention, Learning & Problem-Solving) Cognition is the process ... What Are Some Other Cognitive Problems? What Is Perception? Remember What Is Attention or Concentration? More Resources ...

  10. Bicriteria network design problems

    SciTech Connect

    Marathe, M.V.; Ravi, R.; Sundaram, R.; Ravi, S.S.; Rosenkrantz, D.J.; Hunt, H.B. III

    1994-12-31

    We study several bicriteria network design problems phrased as follows: given an undirected graph and two minimization objectives with a budget specified on one objective, find a subgraph satisfying certain connectivity requirements that minimizes the second objective subject to the budget on the first. Define an ({alpha}, {beta})-approximation algorithm as a polynomial-time algorithm that produces a solution in which the first objective value is at most {alpha} times the budget, and the second objective value is at most {alpha} times the minimum cost of a network obeying the budget oil the first objective. We, present the first approximation algorithms for bicriteria problems obtained by combining classical minimization objectives such as the total edge cost of the network, the diameter of the network and a weighted generalization of the maximum degree of any node in the network. We first develop some formalism related to bicriteria problems that leads to a clean way to state bicriteria approximation results. Secondly, when the two objectives are similar but only differ based on the cost function under which they are computed we present a general parametric search technique that yields approximation algorithms by reducing the problem to one of minimizing a single objective of the same type. Thirdly, we present an O(log n, log n)-approximation algorithm for finding a diameter-constrained minimum cost spanning tree of an undirected graph on n nodes generalizing the notion of shallow, light trees and light approximate shortest-path trees that have been studied before. Finally, for the class of treewidth-bounded graphs, we provide pseudopolynomial-time algorithms for a number of bicriteria problems using dynamic programming. These pseudopolynomial-time algorithms can be converted to fully polynomial-time approximation schemes using a scaling technique.

  11. Physics Problem Workbook, Student Manual.

    ERIC Educational Resources Information Center

    Jones, John L.

    This workbook contains 50 undergraduate physics problems designed for use in conjunction with a computer in a time-sharing mode. Each of the problems includes a statement of the problem topic, a background description of the problem, problem objectives, suggested readings, and a related graph or figure. Various topics in general physics are…

  12. Buffon's Coin Problem and beyond

    ERIC Educational Resources Information Center

    Schneiter, Kady

    2011-01-01

    This article describes an investigation of Buffon's coin problem and related problems with the aid of an applet. The problems are accessible at a variety of grade levels and facilitate making connections between geometry and probability.

  13. Gravitational Many-Body Problem

    SciTech Connect

    Makino, J.

    2008-04-29

    In this paper, we briefly review some aspects of the gravitational many-body problem, which is one of the oldest problems in the modern mathematical science. Then we review our GRAPE project to design computers specialized to this problem.

  14. A Perron-Frobenius theory for block matrices associated to a multiplex network

    NASA Astrophysics Data System (ADS)

    Romance, Miguel; Solá, Luis; Flores, Julio; García, Esther; García del Amo, Alejandro; Criado, Regino

    2015-03-01

    The uniqueness of the Perron vector of a nonnegative block matrix associated to a multiplex network is discussed. The conclusions come from the relationships between the irreducibility of some nonnegative block matrix associated to a multiplex network and the irreducibility of the corresponding matrices to each layer as well as the irreducibility of the adjacency matrix of the projection network. In addition the computation of that Perron vector in terms of the Perron vectors of the blocks is also addressed. Finally we present the precise relations that allow to express the Perron eigenvector of the multiplex network in terms of the Perron eigenvectors of its layers.

  15. MCNP: Photon benchmark problems

    SciTech Connect

    Whalen, D.J.; Hollowell, D.E.; Hendricks, J.S.

    1991-09-01

    The recent widespread, markedly increased use of radiation transport codes has produced greater user and institutional demand for assurance that such codes give correct results. Responding to these pressing requirements for code validation, the general purpose Monte Carlo transport code MCNP has been tested on six different photon problem families. MCNP was used to simulate these six sets numerically. Results for each were compared to the set's analytical or experimental data. MCNP successfully predicted the analytical or experimental results of all six families within the statistical uncertainty inherent in the Monte Carlo method. From this we conclude that MCNP can accurately model a broad spectrum of photon transport problems. 8 refs., 30 figs., 5 tabs.

  16. Solving bearing overheating problems

    SciTech Connect

    Jendzurski, T.

    1995-05-08

    Overheating is a major indicator, along with vibration and noise, of an underlying problem affecting a bearing or related components. Because normal operating temperatures vary widely from one application to another, no single temperature is a reliable sign of overheating in every situation. By observing an application when it is running smoothly, a technician can establish a benchmark temperature for a particular bearing arrangement. Wide deviations from this accepted norm generally indicate troublesome overheating. The list of possible causes of over-heating ranges from out-of-round housings and oversize shaft diameters to excessive lubrication and bearing preloading. These causes fall into two major categories: improper or faulty lubrication and mechanical problems, such as incorrect fits and tolerances. These are discussed along with solutions.

  17. [Mental health problems].

    PubMed

    Momotani, Hiroko; Yamamoto, Haruyoshi

    2014-02-01

    This paper describes current issues in occupational mental health, occupational mental health activities currently underway, and priorities to improve the situation in Japan. A new tool to support these activities is then discussed. The incidence of employee mental health problems is rising, despite efforts to promote occupational mental health activities. The adoption of such activities is lagging behind in medium and small-sized enterprises. Priorities to improve occupational mental health include motivating business operators to address mental health issues, focusing more on prevention, and promoting mental health initiatives in medium and small-sized enterprises. Mental-Rosai, a web-based mental health check system, is a useful tool for the prevention of mental health problems and can provide support for medium and small-sized enterprises. PMID:24605529

  18. Cosmological axino problem

    NASA Astrophysics Data System (ADS)

    Cheung, Clifford; Elor, Gilly; Hall, Lawrence J.

    2012-01-01

    We revisit the cosmology of the supersymmetric QCD axion, highlighting the existence of a serious cosmological axino problem that is fully analogous to the gravitino problem of overclosure via thermal production. A general analysis implies that the QCD axino has a mass greater than or equal to that of the gravitino in the absence of unnatural fine-tuning or sequestering. As a consequence, bounds from thermal gravitino and QCD axino production are complementary in parameter space, and together provide a quite stringent limit on the reheating temperature after inflation given by TR<103-106GeV for an axion decay constant of fa=109-1012GeV. Motivated by this result, we explore the cosmology of gravitino lightest supersymmetric particle and axino next to lightest supersymmetric particle at low TR and present three realistic scenarios for dark matter.

  19. FBST for Cointegration Problems

    NASA Astrophysics Data System (ADS)

    Diniz, M.; Pereira, C. A. B.; Stern, J. M.

    2008-11-01

    In order to estimate causal relations, the time series econometrics has to be aware of spurious correlation, a problem first mentioned by Yule [21]. To solve the problem, one can work with differenced series or use multivariate models like VAR or VEC models. In this case, the analysed series are going to present a long run relation i.e. a cointegration relation. Even though the Bayesian literature about inference on VAR/VEC models is quite advanced, Bauwens et al. [2] highlight that "the topic of selecting the cointegrating rank has not yet given very useful and convincing results." This paper presents the Full Bayesian Significance Test applied to cointegration rank selection tests in multivariate (VAR/VEC) time series models and shows how to implement it using available in the literature and simulated data sets. A standard non-informative prior is assumed.

  20. Modern problems of thermodynamics

    NASA Astrophysics Data System (ADS)

    Novikov, I. I.

    2012-12-01

    The role of energy and methods of its saving for the development of human society and life are analyzed. The importance of future use of space energy flows and energy of water and air oceans is emphasized. The authors consider the idea of the unit for production of electric energy and pure substances using sodium chloride which reserves are limitless on the planet. Looking retrospectively at the development of power engineering from the elementary fire to modern electric power station, we see that the used method of heat production, namely by direct interaction of fuel and oxidizer, is the simplest. However, it may be possible to combust coal, i.e., carbon in salt melt, for instance, sodium chloride that would be more rational and efficient. If the stated problems are solved positively, we would master all energy properties of the substance; and this is the main problem of thermodynamics being one of the sciences on energy.

  1. Hematological Problems of Pregnancy

    PubMed Central

    Ballem, P.J.

    1988-01-01

    Hematologic complications are relatively common in pregnancy. Furthermore, many chronic hematologic disorders require special surveillance and intervention in pregnancy. In this brief review, the author discusses common nutritional anemias in pregnancy. She reviews the disorders of hemoglobin synthesis and the need for early genetic counselling and prenatal diagnosis, as well as the special requirements and problems affected patients encounter in pregnancy. An overview of the frequent causes of thrombocytopenia in pregnancy is given and an approach suggested to the management of both the mother and the fetus. An approach is also presented to the management of women at risk for thrombosis in pregnancy, a particularly vexing and controversial problem. The risks of the various forms of anticoagulation are reviewed. Finally, a brief review of obstetrical hemorrhage is presented along with some guidelines useful in its management. PMID:21253125

  2. The inhibiting bisection problem.

    SciTech Connect

    Pinar, Ali

    2010-11-01

    Given a graph where each vertex is assigned a generation or consumption volume, we try to bisect the graph so that each part has a significant generation/consumption mismatch, and the cutsize of the bisection is small. Our motivation comes from the vulnerability analysis of distribution systems such as the electric power system. We show that the constrained version of the problem, where we place either the cutsize or the mismatch significance as a constraint and optimize the other, is NP-complete, and provide an integer programming formulation. We also propose an alternative relaxed formulation, which can trade-off between the two objectives and show that the alternative formulation of the problem can be solved in polynomial time by a maximum flow solver. Our experiments with benchmark electric power systems validate the effectiveness of our methods.

  3. The Boolean Isomorphism problem

    SciTech Connect

    Agrawal, M.; Thierauf, T.

    1996-12-31

    We investigate the computational complexity of the Boolean Isomorphism problem (BI): on input of two Boolean formulas F and G decide whether there exists a permutation of the variables of G such that F and G become equivalent. Our main result is a one-round interactive proof for BI, where the verifier has access to an NP oracle. To obtain this, we use a recent result from learning theory by Bshouty et.al. that Boolean formulas can be learned probabilistically with equivalence queries and access to an NP oracle. As a consequence, BI cannot be {sigma}{sup p}{sub 2} complete unless the Polynomial Hierarchy collapses. This solves an open problem posed in [BRS95]. Further properties of BI are shown: BI has And- and Or-functions, the counting version, No. BI, can be computed in polynomial time relative to BI, and BI is self-reducible.

  4. Energy - A systems problem

    NASA Technical Reports Server (NTRS)

    Bourke, Roger D.

    1982-01-01

    Energy management in its most comprehensive sense encompasses economic, technical, environmental, and political problems. The present evaluation of prospects notes that opportunities for energy conservation are widespread, in such fields as building air conditioning, transportation, electrical appliances, and industrial processes. Further conservation is expected to be achieved through a combination of technology development and economics; the latter factor must not be unduly influenced by political measures that shield consumers from the true cost of energy.

  5. Working on interesting problems

    NASA Astrophysics Data System (ADS)

    Smith, Arfon M.

    2015-01-01

    BSc Chemistry, The University of Sheffield 2001... PhD Astrochemistry, The University of Nottingham 2006... Scientist at GitHub Inc. 2013.From the outside, the path an individual has taken from academia to industry is not an obvious one. In this session I'll (try and) explain how an interest in software, engineering and chasing interesting problems makes internet startup in San Francisco a great home.

  6. Childhood behavior problems.

    PubMed

    Novak, L L

    1996-01-01

    Educating parents about normal, age-appropriate behavior in their children, teaching them basic behavioral techniques (such as the time-out and positive-reward systems) and giving them specific suggestions for intervention can increase parental confidence and decrease anxiety. Anticipating problems before they develop can help parents prevent inappropriate behavior patterns from developing in their children and may decrease abusive behavior. PMID:8546052

  7. Problem of hidden variables

    NASA Astrophysics Data System (ADS)

    Santos, Emilio

    1992-10-01

    The problem of hidden variables in quantum mechanics is formalized as follows. A general or contextual (noncontextual) hidden-variables theory is defined as a mapping f: Q×M → C (f: Q→C) where Q is the set of projection operators in the appropriate (quantum) Hilbert space, M is the set of maximal Boolean subalgebras of Q and C is a (classical) Boolean algebra. It is shown that contextual (noncontextual) hidden-variables always exist (do not exist).

  8. Ear problems in swimmers.

    PubMed

    Wang, Mao-Che; Liu, Chia-Yu; Shiao, An-Suey; Wang, Tyrone

    2005-08-01

    Acute diffuse otitis externa (swimmer's ear), otomycosis, exostoses, traumatic eardrum perforation, middle ear infection, and barotraumas of the inner ear are common problems in swimmers and people engaged in aqua activities. The most common ear problem in swimmers is acute diffuse otitis externa, with Pseudomonas aeruginosa being the most common pathogen. The symptoms are itching, otalgia, otorrhea, and conductive hearing loss. The treatment includes frequent cleansing of the ear canal, pain control, oral or topical medications, acidification of the ear canal, and control of predisposing factors. Swimming in polluted waters and ear-canal cleaning with cotton-tip applicators should be avoided. Exostoses are usually seen in people who swim in cold water and present with symptoms of accumulated debris, otorrhea and conductive hearing loss. The treatment for exostoses is transmeatal surgical removal of the tumors. Traumatic eardrum perforations may occur during water skiing or scuba diving and present with symptoms of hearing loss, otalgia, otorrhea, tinnitus and vertigo. Tympanoplasty might be needed if the perforations do not heal spontaneously. Patients with chronic otitis media with active drainage should avoid swimming, while patients who have undergone mastoidectomy and who have no cavity problems may swim. For children with ventilation tubes, surface swimming is safe in a clean, chlorinated swimming pool. Sudden sensorineural hearing loss and some degree of vertigo may occur after diving because of rupture of the round or oval window membrane. PMID:16138712

  9. Medical problems of musicians.

    PubMed

    Lockwood, A H

    1989-01-26

    Surveys of performing musicians indicate that almost half of them experience playing-related medical problems, some of which threaten or end their careers. Overuse injuries involving the muscle--tendon unit are the most common problem, with symptoms ranging from mild pain while the musician is playing to pain severe enough to preclude any use of the affected hand. String players are the most commonly affected, and percussionists the least. The most important predisposing characteristic is the use of repetitive movements during long hours of practice, but awkward body positions mandated by the shape and weight of the instrument, the technical difficulty of the repertoire, and unfamiliar instruments may also play a part. Women are more commonly affected than men. Rest is the cornerstone of therapy. Neural impingement syndromes affecting the median or ulnar nerves or the thoracic outlet affect many musicians. Focal dystonias may involve part or all of a hand or the muscles forming the embouchure (the position of the lips in wind players). These are very resistant to therapy and may terminate or drastically alter a career. Stress, especially performance anxiety, may impede performance. Beta-adrenergic blocking agents prevent the symptoms of performance anxiety and are frequently used by musicians without medical supervision. A recognition of the unique problems of musician-patients has led to the formation of successful specialty clinics in a number of cities. PMID:2643048

  10. The Feline Josephus Problem

    NASA Astrophysics Data System (ADS)

    Ruskey, Frank; Williams, Aaron

    In the classic Josephus problem, elements 1, 2,...,n are placed in order around a circle and a skip value k is chosen. The problem proceeds in n rounds, where each round consists of traveling around the circle from the current position, and selecting the kth remaining element to be eliminated from the circle. After n rounds, every element is eliminated. Special attention is given to the last surviving element, denote it by j. We generalize this popular problem by introducing a uniform number of lives ℓ, so that elements are not eliminated until they have been selected for the ℓth time. We prove two main results: 1) When n and k are fixed, then j is constant for all values of ℓ larger than the nth Fibonacci number. In other words, the last surviving element stabilizes with respect to increasing the number of lives. 2) When n and j are fixed, then there exists a value of k that allows j to be the last survivor simultaneously for all values of ℓ. In other words, certain skip values ensure that a given position is the last survivor, regardless of the number of lives. For the first result we give an algorithm for determining j (and the entire sequence of selections) that uses O(n 2) arithmetic operations.

  11. High Altitude Medical Problems

    PubMed Central

    Hultgren, Herbert N.

    1979-01-01

    Increased travel to high altitude areas by mountaineers and nonclimbing tourists has emphasized the clinical problems associated with rapid ascent. Acute mountain sickness affects most sojourners at elevations above 10,000 feet. Symptoms are usually worse on the second or third day after arrival. Gradual ascent, spending one to three days at an intermediate altitude, and the use of acetazolamide (Diamox) will prevent or ameliorate symptoms in most instances. Serious and potentially fatal problems, such as high altitude pulmonary edema or cerebral edema, occur in approximately 0.5 percent to 1.0 percent of visitors to elevations above 10,000 feet—especially with heavy physical exertion on arrival, such as climbing or skiing. Early recognition, high flow oxygen therapy and prompt descent are crucially important in management. Our knowledge of the causes of these and other high altitude problems, such as retinal hemorrhage, systemic edema and pulmonary hypertension, is still incomplete. Even less is known of the effect of high altitudes on medical conditions common at sea level or on the action of commonly used drugs. ImagesFigure 2. PMID:483805

  12. Adolescent Temperament: Childhood Problem Precursors and Problem Behavior Correlates.

    ERIC Educational Resources Information Center

    Windle, Michael

    Interrelations between childhood behavior problems and adolescent temperament, and between adolescent temperament and problem behaviors, were studied. A sample of 311 adolescents with an average age of 15.7 years completed self-report measures regarding behavior problems before age 13, temperament, alcohol consumption, alcohol-related problems,…

  13. Problem-Framing: A perspective on environmental problem-solving

    NASA Astrophysics Data System (ADS)

    Bardwell, Lisa V.

    1991-09-01

    The specter of environmental calamity calls for the best efforts of an involved public. Ironically, the way people understand the issues all too often serves to discourage and frustrate rather than motivate them to action. This article draws from problem-solving perspectives offered by cognitive psychology and conflict management to examine a framework for thinking about environmental problems that promises to help rather than hinder efforts to address them. Problem-framing emphasizes focusing on the problem definition. Since how one defines a problem determines one's understanding of and approach to that problem, being able to redefine or reframe a problem and to explore the “problem space” can help broaden the range of alternatives and solutions examined. Problem-framing incorporates a cognitive perspective on how people respond to information. It explains why an emphasis on problem definition is not part of people's typical approach to problems. It recognizes the importance of structure and of having ways to organize that information on one's problem-solving effort. Finally, problem-framing draws on both cognitive psychology and conflict management for strategies to manage information and to create a problem-solving environment that not only encourages participation but can yield better approaches to our environmental problems.

  14. Space Power Engineering Problems

    NASA Astrophysics Data System (ADS)

    Senkevich, V. P.

    2002-01-01

    Development of space power engineering in the first half of XXI century shall be aimed at preventing the forthcoming energy crisis and ecological catastrophes. The problem can be solved through using solar energy being perpetual, endless, and ecologically safe. As of now, issues on the development and employment of solar power stations and its beaming to the ground stations in the SHF band are put on the agenda. The most pressing problem is to develop orbital solar reflectors to illuminate towns in the polar regions, agricultural regions, and areas of processing sea products. Space-based technologies can be used to deal with typhoons, green house effects, and "ozone holes". Recently, large, frameless film structures formed by centrifugal forces offer the promise of structures for orbital power plants, reflectors, and solar sails. A big success is achieved in the development of power generating solar array elements of amorphous silicon. These innovations would make the development of orbital solar power plants dozens of times cheaper. Such solar arrays shall be used in the nearest future on heavy communication satellites and the Earth remote sensing platforms for generation of 140-160 kW at a specific power beyond 300 W/kg. The cargo traffic needed to develop and maintain the orbital power plants and reflector systems could be equipped with solar sails as the future low thrust propulsion. In 2000, the mankind witnessed an unexpected beginning of energy crisis along with strong hydro- meteorological events (typhoons, floods) that shocked the USA, the Western Europe, England, Japan, and other countries. The total damage is estimated as 90 billions of dollars. The mankind is approaching a boundary beyond which its further existence would depend on how people would learn to control weather and use ecologically safe power sources. Space technology base on the research potential accumulated in the previous century could serve for the solution of this problem.

  15. Mechanics: Ideas, problems, applications

    NASA Astrophysics Data System (ADS)

    Ishlinskii, A. Iu.

    The book contains the published articles and reports by academician Ishlinskii which deal with the concepts and ideas of modern mechanics, its role in providing a general understanding of the natural phenomena, and its applications to various problems in science and engineering. Attention is given to the methodological aspects of mechanics, to the history of the theories of plasticity, friction, gyroscopic and inertial systems, and inertial navigation, and to mathematical methods in mechanics. The book also contains essays on some famous scientists and engineers.

  16. Irrelevance in Problem Solving

    NASA Technical Reports Server (NTRS)

    Levy, Alon Y.

    1992-01-01

    The notion of irrelevance underlies many different works in AI, such as detecting redundant facts, creating abstraction hierarchies and reformulation and modeling physical devices. However, in order to design problem solvers that exploit the notion of irrelevance, either by automatically detecting irrelevance or by being given knowledge about irrelevance, a formal treatment of the notion is required. In this paper we present a general framework for analyzing irrelevance. We discuss several properties of irrelevance and show how they vary in a space of definitions outlined by the framework. We show how irrelevance claims can be used to justify the creation of abstractions thereby suggesting a new view on the work on abstraction.

  17. [Skin problems in joggers].

    PubMed

    Itin, P; Rufli, T

    1986-08-30

    Reports on skin problems in joggers are rare in medical literature. Jogger dermatoses are caused by repeated trauma, mechanic overuse, thermic effects, allergic-toxic reactions and infectious processes. Most common are bullosis mechanica, piezogenic papules, hyperkeratosis haemorrhagica and subungual haematomas. Contact allergies and infections such as athlete's foot, pitted keratolysis and pyoderma are well-known complications in joggers. Frostbite and actinic damage, abrasions of the nipples, collisions with vehicles and injuries by buzzards are further possible incidents to be reckoned with occasionally. In most cases, prophylaxis is possible by training adaptation and use of adequate footwear. Jogger dermatoses usually clear after a suitable jogging-free interval. PMID:3764389

  18. The nanostructure problem

    SciTech Connect

    Billinge, S.

    2010-03-22

    Diffraction techniques are making progress in tackling the difficult problem of solving the structures of nanoparticles and nanoscale materials. The great gift of x-ray crystallography has made us almost complacent in our ability to locate the three-dimensional coordinates of atoms in a crystal with a precision of around 10{sup -4} nm. However, the powerful methods of crystallography break down for structures in which order only extends over a few nanometers. In fact, as we near the one hundred year mark since the birth of crystallography, we face a resilient frontier in condensed matter physics: our inability to routinely and robustly determine the structure of complex nanostructured and amorphous materials. Knowing the structure and arrangement of atoms in a solid is so fundamental to understanding its properties that the topic routinely occupies the early chapters of every solid-state physics textbook. Yet what has become clear with the emergence of nanotechnology is that diffraction data alone may not be enough to uniquely solve the structure of nanomaterials. As part of a growing effort to incorporate the results of other techniques to constrain x-ray refinements - a method called 'complex modeling' which is a simple but elegant approach for combining information from spectroscopy with diffraction data to solve the structure of several amorphous and nanostructured materials. Crystallography just works, so we rarely question how and why this is so, yet understanding the physics of diffraction can be very helpful as we consider the nanostructure problem. The relationship between the electron density distribution in three dimensions (i.e., the crystal structure) and an x-ray diffraction pattern is well established: the measured intensity distribution in reciprocal space is the square of the Fourier transform of the autocorrelation function <{rho}(r){rho}(r+r')> of the electron density distribution {rho}(r). The fact that we get the autocorrelation function

  19. Uncovering Sexual Problems

    PubMed Central

    Cohen, May

    1977-01-01

    While patients frequently make it difficult for us to uncover their sexual concerns, a much greater difficulty is due to physicians' unwillingness to deal with this subject. Physicians need to acquire basic knowledge about human sexuality as well as skills in making patients feel comfortable and open. A non-judgmental attitude is essential. The physician will also be able to anticipate and prevent sexual distress by education. Expertise must be developed in differentiating those problems requiring referral for specialized sexual counselling from those which the family physician can handle. PMID:21304865

  20. Problem-Based Learning Tools

    ERIC Educational Resources Information Center

    Chin, Christine; Chia, Li-Gek

    2008-01-01

    One way of implementing project-based science (PBS) is to use problem-based learning (PBL), in which students formulate their own problems. These problems are often ill-structured, mirroring complex real-life problems where data are often messy and inclusive. In this article, the authors describe how they used PBL in a ninth-grade biology class in…

  1. Problem Solving in the Professions.

    ERIC Educational Resources Information Center

    Jackling, Noel; And Others

    1990-01-01

    It is proposed that algorithms and heuristics are useful in improving professional problem-solving abilities when contextualized within the academic discipline. A basic algorithm applied to problem solving in undergraduate engineering education and a similar algorithm applicable to legal problems are used as examples. Problem complexity and…

  2. A Method for Solving Problems.

    ERIC Educational Resources Information Center

    Knoop, Robert

    1987-01-01

    Problem solving and decision making are considered to be keys to successful management. A normative method for problem solving is presented, suggesting that the analysis of the problem be structured along a five-step procedure: problem identification, analysis, decision alternatives, decision making, and decision implementation. Follow-up…

  3. Problem Order Implications for Learning

    ERIC Educational Resources Information Center

    Li, Nan; Cohen, William W.; Koedinger, Kenneth R.

    2013-01-01

    The order of problems presented to students is an important variable that affects learning effectiveness. Previous studies have shown that solving problems in a blocked order, in which all problems of one type are completed before the student is switched to the next problem type, results in less effective performance than does solving the problems…

  4. Design Problems for Secondary Students

    ERIC Educational Resources Information Center

    Jonassen, David H.

    2011-01-01

    Are there different kinds of design problems? Jonassen (2011) argued that problems vary in terms of structuredness, complexity, and context. On the structuredness and complexity continua, design problems tend to be the most ill-structured and complex. Brown and Chandrasekaran suggest that design problems may vary along a continuum from…

  5. Posing Problems: Two Classroom Examples.

    ERIC Educational Resources Information Center

    Leung, Shukkwan S.; Wu, Rui-xiang

    1999-01-01

    Shares two lessons in which students help teachers pose problems and discover the importance of posing problems properly. Presents a fifth-grade lesson in which students found a mistake in a proportion problem, and an eighth-grade lesson that discusses a geometry problem with insufficient information. (ASK)

  6. Methodological Problems of Nanotechnoscience

    NASA Astrophysics Data System (ADS)

    Gorokhov, V. G.

    Recently, we have reported on the definitions of nanotechnology as a new type of NanoTechnoScience and on the nanotheory as a cluster of the different natural and engineering theories. Nanotechnology is not only a new type of scientific-engineering discipline, but it evolves also in a “nonclassical” way. Nanoontology or nano scientific world view has a function of the methodological orientation for the choice the theoretical means and methods toward a solution to the scientific and engineering problems. This allows to change from one explanation and scientific world view to another without any problems. Thus, nanotechnology is both a field of scientific knowledge and a sphere of engineering activity, in other words, NanoTechnoScience is similar to Systems Engineering as the analysis and design of large-scale, complex, man/machine systems but micro- and nanosystems. Nano systems engineering as well as Macro systems engineering includes not only systems design but also complex research. Design orientation has influence on the change of the priorities in the complex research and of the relation to the knowledge, not only to “the knowledge about something”, but also to the knowledge as the means of activity: from the beginning control and restructuring of matter at the nano-scale is a necessary element of nanoscience.

  7. PSYCHOSOMATIC PROBLEMS IN UROLOGY

    PubMed Central

    Auerback, Alfred; Smith, Donald R.

    1952-01-01

    The intimate relationship between the urinary and genital systems permits stimuli in one system to influence the other. At least 15 per cent of women with symptoms of cystitis have no organic basis for their complaints. In psychiatric studies it has been noted that sexual conflict is the primary etiological factor in these patients. In some cases, continuance of the disorder leads to irreversible organic change. Urinary symptoms such as frequency, urgency, burning or retention are most common in women and become an automatic response to anxiety-provoking or sexual stimuli. In men, functional urinary symptoms are relatively infrequent. Often they indicate problems of genital dysfunction. Complaints of impotence, penile pain, testicular pain, or non-specific urethritis stem back to difficulties in their sexual lives. Many of the patients have symptoms of a generalized anxiety tension state due to sexual problems. A purely organic consideration of genitourinary disorders will lead to erroneous conclusions and unsatisfactory therapeutic results. The psychosomatic approach—that is, considering both physical and psychological aspects—will explain many hitherto difficult cases. PMID:14886756

  8. Microchip problems plague DOD

    NASA Astrophysics Data System (ADS)

    Smith, R. J.

    1984-10-01

    The major issues in the controversy over the discovery of millions of defective microchips sold to the DOD by the Texas Instruments (TI) corporation are outlined. Defects in the microcircuits are blamed on inadequate testing procedures performed by TI during manufacture, and on inadequate testing procedures used by a subcontractor especially contracted to test the chips. Because the problem persisted over a period of years, defects might be possible in as many as 100 million chips used in a broad range of military applications including the Trident submarine, the B-52, B-1B, F-15, F-111, F-4, A-6, and A-7 aircraft, the Harpoon and HARM missile systems, and the Space Shuttles Discovery and Challenger. It is pointed out that although TI has accepted responsibility for the defective chips, little will be done by the DOD to compel the company to replace them, or to upgrade testing procedures. It is concluded that the serious nature of the problem could renew interest in recommendations for the standardization of military microcircuits.

  9. Abstraction and Problem Reformulation

    NASA Technical Reports Server (NTRS)

    Giunchiglia, Fausto

    1992-01-01

    In work done jointly with Toby Walsh, the author has provided a sound theoretical foundation to the process of reasoning with abstraction (GW90c, GWS9, GW9Ob, GW90a). The notion of abstraction formalized in this work can be informally described as: (property 1), the process of mapping a representation of a problem, called (following historical convention (Sac74)) the 'ground' representation, onto a new representation, called the 'abstract' representation, which, (property 2) helps deal with the problem in the original search space by preserving certain desirable properties and (property 3) is simpler to handle as it is constructed from the ground representation by "throwing away details". One desirable property preserved by an abstraction is provability; often there is a relationship between provability in the ground representation and provability in the abstract representation. Another can be deduction or, possibly inconsistency. By 'throwing away details' we usually mean that the problem is described in a language with a smaller search space (for instance a propositional language or a language without variables) in which formulae of the abstract representation are obtained from the formulae of the ground representation by the use of some terminating rewriting technique. Often we require that the use of abstraction results in more efficient .reasoning. However, it might simply increase the number of facts asserted (eg. by allowing, in practice, the exploration of deeper search spaces or by implementing some form of learning). Among all abstractions, three very important classes have been identified. They relate the set of facts provable in the ground space to those provable in the abstract space. We call: TI abstractions all those abstractions where the abstractions of all the provable facts of the ground space are provable in the abstract space; TD abstractions all those abstractions wllere the 'unabstractions' of all the provable facts of the abstract space are

  10. Understanding the Problem. Problem Solving and Communication Activity Series. The Math Forum: Problems of the Week

    ERIC Educational Resources Information Center

    Math Forum @ Drexel, 2009

    2009-01-01

    Different techniques for understanding a problem can lead to ideas for never-used-before solutions. Good problem-solvers use a problem-solving strategy and may come back to it frequently while they are working on the problem to refine their strategy, see if they can find better solutions, or find other questions. Writing is an integral part of…

  11. Problems of massive gravities

    NASA Astrophysics Data System (ADS)

    Deser, S.; Izumi, K.; Ong, Y. C.; Waldron, A.

    2015-01-01

    The method of characteristics is a key tool for studying consistency of equations of motion; it allows issues such as predictability, maximal propagation speed, superluminality, unitarity and acausality to be addressed without requiring explicit solutions. We review this method and its application to massive gravity (mGR) theories to show the limitations of these models' physical viability: Among their problems are loss of unique evolution, superluminal signals, matter coupling inconsistencies and micro-acausality (propagation of signals around local closed time-like curves (CTCs)/closed causal curves (CCCs)). We extend previous no-go results to the entire three-parameter range of mGR theories. It is also argued that bimetric models suffer a similar fate.

  12. [Hypersomnia: a diagnostic problem].

    PubMed

    Kranenburg, Guido; Teunissen, Laurien L

    2014-01-01

    Hypersomnia is a frequently occurring problem. When taking a medical history it is important to distinguish between fatigue and sleepiness. We present a 14-year-old girl with narcolepsy and a 59-year-old man with idiopathic hypersomnia. Features that are typical of narcolepsy are cataplexy and weight gain. Features that are typical of both narcolepsy and idiopathic hypersomnia are daytime naps, insomnia, sleep paralysis and hypnagogic hallucinations. Additional testing in patients with hypersomnia should include a polysomnography in order to exclude other sleeping disorders, and a mean sleep latency test. Practice shows that both patients with narcolepsy and those with idiopathic hypersomnia benefit from treatment with stimulating drugs such as modafinil. PMID:25096034

  13. The Microchp Scheduling Problem

    NASA Astrophysics Data System (ADS)

    Bosman, M. G. C.; Bakker, V.; Molderink, A.; Hurink, J. L.; Smit, G. J. M.

    2009-08-01

    The increasing penetration of renewable energy sources, the demand for more energy efficient electricity production and the increase in distributed electricity generation causes a shift in the way electricity is produced and consumed. The downside of these changes in the electricity grid is that network stability and controllability becomes more difficult compared to the old situation. The new network has to accommodate various means of production, consumption and buffering and needs to offer control over the energy flows between these three elements. In order to offer such a control mechanism we need to know more about the individual aspects. In this paper we focus on the modelling of distributed production. Especially we look at the use of microCHP (Combined Heat and Power) appliances in a group of houses. The problem of planning the production runs of the microCHP is modelled via an ILP formulation both for a single house and for a group of houses.

  14. The four bars problem

    NASA Astrophysics Data System (ADS)

    Mauroy, Alexandre; Taslakian, Perouz; Langerman, Stefan; Jungers, Raphaël

    2016-09-01

    A four-bar linkage is a mechanism consisting of four rigid bars which are joined by their endpoints in a polygonal chain and which can rotate freely at the joints (or vertices). We assume that the linkage lies in the 2-dimensional plane so that one of the bars is held horizontally fixed. In this paper we consider the problem of reconfiguring a four-bar linkage using an operation called a pop. Given a four-bar linkage, a pop reflects a vertex across the line defined by its two adjacent vertices along the polygonal chain. Our main result shows that for certain conditions on the lengths of the bars, the neighborhood of any configuration that can be reached by smooth motion can also be reached by pops. The proof relies on the fact that pops are described by a map on the circle with an irrational number of rotation.

  15. The Brazil nut problem

    NASA Astrophysics Data System (ADS)

    Huerta, Dora; Ruiz-Suarez, Jesus

    2004-03-01

    The segregation of large intruders in a vertically vibrated granular bed is studied. We measure rising times a function of density, diameter and depth; for two different sinusoidal excitations. Our results shed definitive light to explain the fundamental aspects of the fascinating Brazil nut problem. At low frequencies (high amplitudes), inertia and convection are the only mechanisms behind segregation. Inertia dominates when the relative density of the intruder is greater than one and convection when it is less than one. At high frequencies (small amplitudes), where convection is suppressed, segregation occurs by buoyancy or sinkage. Finally, when the diameter of the intruders is changed, the well known paradigm "larger intruders rise faster" fails if the mass of the intruders is kept constant (while their relative densities are greater than one).

  16. PROBLEMS OF HOMOSEXUALITY

    PubMed Central

    Reider, Norman

    1957-01-01

    Moral, religious and legal attitudes in attempts to control sexual behavior have interfered with a clear view of the medical and psychological aspects of homosexuality. This phenomenon is probably much less destructive of social aspects of our society and culture than is generally believed, since it is actually more widespread than is generally acknowledged. Homosexuality probably has hormonal and undoubtedly social and psychological factors, the latter of which are the only ones which can be worked with successfully in our present state of knowledge. A general practitioner's task is to aid those who wish and need help with this problem in finding psychiatric treatment in the same way that persons with any other emotional disturbance are referred. This should be carried out without bias just as with any other emotional disturbance. PMID:13426813

  17. The problem of choice

    PubMed Central

    Naqvi, Hassan R; Mathur, Shawn; Covarrubias, David; Curcio, Josephine A; Schmidt, Christian

    2008-01-01

    Convictions are a driving force for actions. Considering that every individual has a different set of convictions and larger groups act once a consensus decision is reached, one can see that debate is an inherent exercise in decision-making. This requires a sustainably generated surplus to allow time for intellectual exchange, gathering of information and dissemination of findings. It is essential that the full spectrum of options remain treated equally. At the end of this process, a choice has to be made. Looking back at a later time point, a retrospective analysis sometimes reveals that the choice was neither completely free nor a truly conscious one. Leaving the issue of consequences of a once made decision aside, we wish to contribute to the debate of the problem of choice. PMID:19025607

  18. Wicked Problem Solvers.

    PubMed

    Edmondson, Amy C

    2016-06-01

    Companies today increasingly rely on teams that span many industries for radical innovation, especially to solve "wicked problems." So leaders have to understand how to promote collaboration when roles are uncertain, goals are shifting, expertise and organizational cultures are varied, and participants have clashing or even antagonistic perspectives. HBS professor Amy Edmondson has studied more than a dozen cross-industry innovation projects, among them the creation of a new city, a mango supply-chain transformation, and the design and construction of leading-edge buildings. She has identified the leadership practices that make successful cross-industry teams work: fostering an adaptable vision, promoting psychological safety, enabling knowledge sharing, and encouraging collaborative innovation. Though these practices are broadly familiar, their application within cross-industry teams calls for unique leadership approaches that combine flexibility, open-mindedness, humility, and fierce resolve. PMID:27491195

  19. [Legionellosis, a tourist problem?].

    PubMed

    Kistler, W; Fleisch, F; Reinhart, W H; Wieland, T

    2002-07-31

    Legionellosis is a relatively rare disease characterized by an often prolonged and complicated course even in immunocompetent patients. Its diagnosis is mandatory for therapeutic and epidemiologic reasons. At the Kantonsspital Chur between 1998 and 2001, 6 cases of legionellosis have been observed: four of them were travel-associated and one concerned a local hotel employee. Due to the increasing international mobility epidemiologic investigations for the localization and elimination of the sources of infection are very difficult. A european task force, the European Working Group for Legionella Infections (EWGLI/www.ewgli.org) is addressing this problem. It is a matter of debate to what extent the public should be informed about sources of legionellosis (so called legionella hotels). PMID:12212344

  20. The attitude control problem

    NASA Technical Reports Server (NTRS)

    Wen, John Ting-Yung; Kreutz-Delgado, Kenneth

    1991-01-01

    A general framework for the analysis of the attitude tracking control problem for a rigid body is presented. A large family of globally stable control laws is obtained by using the globally nonsingular unit quaternion representation in a Lyapunov function candidate whose form is motivated by the consideration of the total energy of the rigid body. The controllers share the common structure of a proportional-derivative feedback plus some feedforward which can be zero (the model-independent case), the Coriolis torque compensation, or an adaptive compensation. These controller structures are compared in terms of the requirement on the a priori model information, guaranteed transient performance, and robustness. The global stability of the Luh-Walker-Paul robot end-effector controller is also analyzed in this framework.

  1. The worldwide "wildfire" problem.

    PubMed

    Gill, A Malcolm; Stephens, Scott L; Cary, Geoffrey J

    2013-03-01

    The worldwide "wildfire" problem is headlined by the loss of human lives and homes, but it applies generally to any adverse effects of unplanned fires, as events or regimes, on a wide range of environmental, social, and economic assets. The problem is complex and contingent, requiring continual attention to the changing circumstances of stakeholders, landscapes, and ecosystems; it occurs at a variety of temporal and spatial scales. Minimizing adverse outcomes involves controlling fires and fire regimes, increasing the resistance of assets to fires, locating or relocating assets away from the path of fires, and, as a probability of adverse impacts often remains, assisting recovery in the short-term while promoting the adaptation of societies in the long-term. There are short- and long-term aspects to each aspect of minimization. Controlling fires and fire regimes may involve fire suppression and fuel treatments such as prescribed burning or non-fire treatments but also addresses issues associated with unwanted fire starts like arson. Increasing the resistance of assets can mean addressing the design and construction materials of a house or the use of personal protective equipment. Locating or relocating assets can mean leaving an area about to be impacted by fire or choosing a suitable place to live; it can also mean the planning of land use. Assisting recovery and promoting adaptation can involve insuring assets and sharing responsibility for preparedness for an event. There is no single, simple, solution. Perverse outcomes can occur. The number of minimizing techniques used, and the breadth and depth of their application, depends on the geographic mix of asset types. Premises for policy consideration are presented. PMID:23634593

  2. The Billiard Problem.

    NASA Astrophysics Data System (ADS)

    Friedman, Barry Alan

    The billiard problem is studied in this thesis. The first chapter consists of a general introduction to the billiard problem and the question of the long time behavior of Hamiltonian systems. In Chapter 2 we study the behavior of the Kolmogorov -Sinai entropy for Sinai billiard systems. In particular, we numerically calculate the Kolmogorov-Sinai entropy h(,S('t)) for the two dimensional square and triangular Sinai billiards. We find, in both cases, for small scatterer radius R that h(,S('t))<(tau)> (DBLTURN) -2 Ln R where <(tau)> is the mean free time between collisions. Asymptotic analysis in support of this rela- tion is given. We present conjectures that a similar relationship holds for all Sinai billiard systems. We also find that the Kolmogorov-Sinai entropy is not affected by the change from bounded to unbounded horizon. In Chapter 3 we study the decay of the velocity autocorrelation function for the classical periodic Lorentz gas. We study numerically the behavior of the velocity autocorrelation function for the triangu- lar periodic Lorentz gas as the horizon changes from bounded to unbounded. We note a qualitative difference in the velocity auto- correlation function between the case of bounded and unbounded horizon; when the horizon is bounded the decay is exponential, when the horizon is unbounded we find an algebraic decay. In the case of unbounded horizon (for the triangular case) numerical evidence and simple arguments indicate a 1/t decay rate. Similar arguments for a 1/t decay rate for the square periodic Lorentz gas in two and three dimensions are given. We thus conclude that for the square periodic Lorentz gas and the triangular periodic Lorentz gas (when the hori- zon is unbounded) the diffusion constant does not exist.

  3. Addressing problems of employee performance.

    PubMed

    McConnell, Charles R

    2011-01-01

    Employee performance problems are essentially of 2 kinds: those that are motivational in origin and those resulting from skill deficiencies. Both kinds of problems are the province of the department manager. Performance problems differ from problems of conduct in that traditional disciplinary processes ordinarily do not apply. Rather, performance problems are addressed through educational and remedial processes. The manager has a basic responsibility in ensuring that everything reasonable is done to help each employee succeed. There are a number of steps the manager can take to address employee performance problems. PMID:21537142

  4. Computer Problem-Solving Coaches

    NASA Astrophysics Data System (ADS)

    Hsu, Leon; Heller, Kenneth

    2005-09-01

    Computers might be able to play an important role in physics instruction by coaching students to develop good problem-solving skills. Building on previous research on student problem solving and on designing computer programs to teach cognitive skills, we are developing a prototype computer coach to provide students with guided practice in solving problems. In addition to helping students become better problem solvers, such programs can be useful in studying how students learn to solve problems and how and if problem-solving skills can be transferred from a computer to a pencil-and-paper environment.

  5. Developing Metacognitive and Problem-Solving Skills through Problem Manipulation

    ERIC Educational Resources Information Center

    Parker Siburt, Claire J.; Bissell, Ahrash N.; Macphail, Richard A.

    2011-01-01

    In a collaborative effort between the our university's department of chemistry and the academic resource center, we designed a model for general chemistry recitation based on a problem manipulation method in which students actively assess the skills and knowledge used to answer a chemical problem and then manipulate the problem to create a new…

  6. Adolescent Problem Behavior and Problem Driving in Young Adulthood

    ERIC Educational Resources Information Center

    Bingham, C. Raymond; Shope, Jean T.

    2004-01-01

    Motor vehicle crashes are the leading cause of death among drivers younger than age 35, making problem driving behavior among young drivers a significant public concern. Effective intervention requires a better understanding of the antecedents of problem driving. Problem behavior theory, social control theory, and Kandel's model of substance use…

  7. Problem Solvers: Problem--How Long Can You Stand?

    ERIC Educational Resources Information Center

    Teaching Children Mathematics, 2010

    2010-01-01

    Healthy lifestyles are increasingly emphasized these days. This month the authors begin a series of mathematical problems that also address physical activity. They hope that these problems offer opportunities to investigate mathematics and also reinforce the desire to lead a healthy life. In their first problem of the academic year, students…

  8. Problem Solving through an Optimization Problem in Geometry

    ERIC Educational Resources Information Center

    Poon, Kin Keung; Wong, Hang-Chi

    2011-01-01

    This article adapts the problem-solving model developed by Polya to investigate and give an innovative approach to discuss and solve an optimization problem in geometry: the Regiomontanus Problem and its application to football. Various mathematical tools, such as calculus, inequality and the properties of circles, are used to explore and reflect…

  9. Goldfishing by gauge theory

    SciTech Connect

    Calogero, F.; Langmann, E.

    2006-08-15

    A new solvable many-body problem of goldfish type is identified and used to revisit the connection between two different approaches to solvable dynamical systems. An isochronous variant of this model is identified and investigated. Alternative versions of these models are presented. The behavior of the alternative isochronous model near its equilibrium configurations is investigated, and a remarkable Diophantine result, as well as related Diophantine conjectures, are thereby obtained.

  10. Goldfishing by gauge theory

    NASA Astrophysics Data System (ADS)

    Calogero, F.; Langmann, E.

    2006-08-01

    A new solvable many-body problem of goldfish type is identified and used to revisit the connection between two different approaches to solvable dynamical systems. An isochronous variant of this model is identified and investigated. Alternative versions of these models are presented. The behavior of the alternative isochronous model near its equilibrium configurations is investigated, and a remarkable Diophantine result, as well as related Diophantine conjectures, are thereby obtained.

  11. Energy Problems and Environmental Concern

    ERIC Educational Resources Information Center

    Train, Russell E.

    1973-01-01

    Discusses problems encountered in energy extraction and consumption, involving nuclear power plant construction, environmental consequences of energy systems, and energy conservation ethics. Indicates that the increasing concern over environmental quality is not the true cause of present energy problems. (CC)

  12. Dementia - behavior and sleep problems

    MedlinePlus

    ... gov/ency/patientinstructions/000029.htm Dementia - behavior and sleep problems To use the sharing features on this ... sleep and stay asleep Tips for Behavior and Sleep Problems Having a daily routine may help. Calmly ...

  13. Strengthening Programs through Problem Solving.

    ERIC Educational Resources Information Center

    Dyer, Jim

    1993-01-01

    Describes a secondary agricultural education program that was a dumping ground for academically disadvantaged students. Discusses how such a program can be improved by identifying problems and symptoms, treating problems, and goal setting. (JOW)

  14. Decision Analysis for Environmental Problems

    EPA Science Inventory

    Environmental management problems are often complex and uncertain. A formal process with proper guidance is needed to understand the issues, identify sources of disagreement, and analyze the major uncertainties in environmental problems. This course will present a process that fo...

  15. Dental Health and Orthodontic Problems

    MedlinePlus

    ... Text Size Email Print Share Dental Health and Orthodontic Problems Page Content Article Body Dental Health Twin ... color can be tinted to match the teeth. Orthodontic Problems Crooked teeth, overbites and underbites are best ...

  16. Sherlock Holmes, Master Problem Solver.

    ERIC Educational Resources Information Center

    Ballew, Hunter

    1994-01-01

    Shows the connections between Sherlock Holmes's investigative methods and mathematical problem solving, including observations, characteristics of the problem solver, importance of data, questioning the obvious, learning from experience, learning from errors, and indirect proof. (MKR)

  17. The Problem of Defining Intelligence.

    ERIC Educational Resources Information Center

    Lubar, David

    1981-01-01

    The major philosophical issues surrounding the concept of intelligence are reviewed with respect to the problems surrounding the process of defining and developing artificial intelligence (AI) in computers. Various current definitions and problems with these definitions are presented. (MP)

  18. Enhancing chemistry problem-solving achievement using problem categorization

    NASA Astrophysics Data System (ADS)

    Bunce, Diane M.; Gabel, Dorothy L.; Samuel, John V.

    The enhancement of chemistry students' skill in problem solving through problem categorization is the focus of this study. Twenty-four students in a freshman chemistry course for health professionals are taught how to solve problems using the explicit method of problem solving (EMPS) (Bunce & Heikkinen, 1986). The EMPS is an organized approach to problem analysis which includes encoding the information given in a problem (Given, Asked For), relating this to what is already in long-term memory (Recall), and planning a solution (Overall Plan) before a mathematical solution is attempted. In addition to the EMPS training, treatment students receive three 40-minute sessions following achievement tests in which they are taught how to categorize problems. Control students use this time to review the EMPS solutions of test questions. Although problem categorization is involved in one section of the EMPS (Recall), treatment students who received specific training in problem categorization demonstrate significantly higher achievement on combination problems (those problems requiring the use of more than one chemical topic for their solution) at (p = 0.01) than their counterparts. Significantly higher achievement for treatment students is also measured on an unannounced test (p = 0.02). Analysis of interview transcripts of both treatment and control students illustrates a Rolodex approach to problem solving employed by all students in this study. The Rolodex approach involves organizing equations used to solve problems on mental index cards and flipping through them, matching units given when a new problem is to be solved. A second phenomenon observed during student interviews is the absence of a link in the conceptual understanding of the chemical concepts involved in a problem and the problem-solving skills employed to correctly solve problems. This study shows that explicit training in categorization skills and the EMPS can lead to higher achievement in complex problem

  19. Large Spectral Library Problem

    SciTech Connect

    Chilton, Lawrence K.; Walsh, Stephen J.

    2008-10-03

    Hyperspectral imaging produces a spectrum or vector at each image pixel. These spectra can be used to identify materials present in the image. In some cases, spectral libraries representing atmospheric chemicals or ground materials are available. The challenge is to determine if any of the library chemicals or materials exist in the hyperspectral image. The number of spectra in these libraries can be very large, far exceeding the number of spectral channels collected in the ¯eld. Suppose an image pixel contains a mixture of p spectra from the library. Is it possible to uniquely identify these p spectra? We address this question in this paper and refer to it as the Large Spectral Library (LSL) problem. We show how to determine if unique identi¯cation is possible for any given library. We also show that if p is small compared to the number of spectral channels, it is very likely that unique identi¯cation is possible. We show that unique identi¯cation becomes less likely as p increases.

  20. Inverse Problems of Thermoelectricity

    NASA Astrophysics Data System (ADS)

    Anatychuk, L. I.; Luste, O. J.; Kuz, R. V.; Strutinsky, M. N.

    2011-05-01

    Classical thermoelectricity is based on the use of the Seebeck and Thomson effects that occur in the near-contact areas between n- and p-type materials. A conceptually different approach to thermoelectric power converter design that is based on the law of thermoelectric induction of currents is also known. The efficiency of this approach has already been demonstrated by its first applications. More than 10 basically new types of thermoelements were discovered with properties that cannot be achieved by thermocouple power converters. Therefore, further development of this concept is of practical interest. This paper provides a classification and theory for solving the inverse problems of thermoelectricity that form the basis for devising new thermoelement types. Computer methods for their solution for anisotropic and inhomogeneous media are elaborated. Regularities related to thermoelectric current excitation in anisotropic and inhomogeneous media are established. The possibility of obtaining eddy currents of a particular configuration through control of the temperature field and material parameters for the creation of new thermo- element types is demonstrated for three-dimensional (3D) models of anisotropic and inhomogeneous media.

  1. Problems of rapid growth.

    PubMed

    Kim, T D

    1980-01-01

    South Korea's export-oriented development strategy has achieved a remarkable growth record, but it has also brought 2 different problems: 1) since the country's exports accounted for about 1% of total world export volume, the 1st world has become fearful about Korea's aggressive export drive; and 2) the fact that exports account for over 30% of its total gross national product (GNP) exposes the vulnerability of South Korea's economy itself. South Korea continues to be a poor nation, although it is rated as 1 of the most rapidly growing middle income economies. A World Bank 1978 report shows Korea to be 28th of 58 middle income countries in terms of per capita GNP in 1976. Of 11 newly industrializing countries (NIC), 5 in the European continent are more advanced than the others. A recent emphasis on the basic human needs approach has tended to downgrade the concept of GNP. Korea has only an abundant labor force and is without any natural resources. Consequently, Korea utilized an export-oriented development strategy. Oil requirements are met with imports, and almost all raw materials to be processed into exportable products must be imported. To pay import bills Korea must export and earn foreign exchange. It must be emphasized that foreign trade must always be 2-way traffic. In order to export more to middle income countries like Korea, the countries of the 1st world need to ease their protectionist measures against imports from developing countries. PMID:12336527

  2. Identifying and managing problem drinkers.

    PubMed Central

    Kahan, M.

    1996-01-01

    Problem drinking is far more common than severe alcohol dependence and is associated with considerable morbidity and health care costs. Whereas patients with alcohol dependence respond best to intensive treatment, one or more brief sessions of physician advice and counseling reduces alcohol consumption among problem drinkers. The two most useful tools to identify problem drinkers are the CAGE and the drinking problem question. PMID:8653034

  3. The lawnmower problem and other geometric path covering problems

    SciTech Connect

    Fekete, S.; Arkin, E.; Mitchell, J.

    1994-12-31

    We discuss the Lawnmower Problem: Given a polygonal region, find the shortest closed path along which we have to move a given object (typically a square or a circle), such that any point of the region will be covered by the object for some position of it movement. In another version of the problem, known as the Milling Problem, the object has to stay within the region at all times. Practical motivations for considering the Lawnmower Problem come from manufacturing (spray painting, quality control), geography (aerial surveys), optimization (tour planning for a large number of clients with limited mobility), and gardening. The Milling Problem has gained attention by its importance for NC pocket machining. We show that both problems are NP-hard and discuss approximation methods for various versions of the problem.

  4. Common problems in gastrointestinal radiology

    SciTech Connect

    Thompson, W.M.

    1989-01-01

    This book covers approximately 70 common diagnostic problems in gastro-intestinal radiology. Each problem, includes a short illustrated case history, a discussion of the radiologic findings, a general discussion of the case, the differential diagnosis, a description of the management of the problem or procedure used, and, where appropriate, the results of the therapy suggested.

  5. The Problem-Solving Revolution.

    ERIC Educational Resources Information Center

    Bardige, Art

    1983-01-01

    Discusses the use of microcomputers and software as problem-solving tools, including comments on "TK! Solver," automatic problem-solving program (reviewed in detail on pp.84-86 in this same issue). Also discusses problem-solving approaches to bridge the disciplines, such as music/physics, junior high science/mathematics (genetics),…

  6. Crustal growth: Some major problems

    NASA Technical Reports Server (NTRS)

    Arculus, R. J.

    1988-01-01

    Fundamental problems with models currently used to explain the genesis and evolution of continental crust were raised. These problems focus around the difficulty of generating the upper continental crust from a lower crustal or mantle protolith without leaving a very large, and so far undetected, volume of restite. No conclusive resolution to the problems was achieved.

  7. The Identity of Problem Solving

    ERIC Educational Resources Information Center

    Mamona-Downs, Joanna; Downs, Martin

    2005-01-01

    This paper raises issues motivated by considering the "identity" of problem solving. This means that we are concerned with how other mathematics education topics impinge on problem solving, and with themes that naturally arise within the problem-solving agenda. We claim that some of these issues need more attention by educational research, while…

  8. Must "Hard Problems" Be Hard?

    ERIC Educational Resources Information Center

    Kolata, Gina

    1985-01-01

    To determine how hard it is for computers to solve problems, researchers have classified groups of problems (polynomial hierarchy) according to how much time they seem to require for their solutions. A difficult and complex proof is offered which shows that a combinatorial approach (using Boolean circuits) may resolve the problem. (JN)

  9. Supporting Problem Solving in PBL

    ERIC Educational Resources Information Center

    Jonassen, David

    2011-01-01

    Although the characteristics of PBL (problem focused, student centered, self-directed, etc.) are well known, the components of a problem-based learning environment (PBLE) and the cognitive scaffolds necessary to support learning to solve different kinds of problems with different learners is less clear. This paper identifies the different…

  10. Families and Definitions of Problems.

    ERIC Educational Resources Information Center

    Aldous, Joan; Ganey, Rodney

    Problem definition appears to influence problem solving outcomes with respect to their quality. In order to determine whether or not families, confronted as a group by a series of possibly problematic situations, would engage in a problem definition phase, and whether or not the phase or its absence would be related to family members' satisfaction…

  11. Problem Analysis: Challenging All Learners

    ERIC Educational Resources Information Center

    Garcia, Katie; Davis, Alicia

    2013-01-01

    In this article, Garcia and Davis describe problem analysis as the process of examining a given mathematics exercise to find ways in which the problem can be modified and extended to create a richer learning opportunity for students. Students are often reluctant to attempt what they perceive to be higher-order thinking problems, but problem…

  12. Problem Reporting System

    NASA Technical Reports Server (NTRS)

    Potter, Don; Serian, Charles; Sweet, Robert; Sapir, Babak; Gamez, Enrique; Mays, David

    2008-01-01

    The Problem Reporting System (PRS) is a Web application, running on two Web servers (load-balanced) and two database servers (RAID-5), which establishes a system for submission, editing, and sharing of reports to manage risk assessment of anomalies identified in NASA's flight projects. PRS consolidates diverse anomaly-reporting systems, maintains a rich database set, and incorporates a robust engine, which allows tracking of any hardware, software, or paper process by configuring an appropriate life cycle. Global and specific project administration and setup tools allow lifecycle tailoring, along with customizable controls for user, e-mail, notifications, and more. PRS is accessible via the World Wide Web for authorized user at most any location. Upon successful log-in, the user receives a customizable window, which displays time-critical 'To Do' items (anomalies requiring the user s input before the system moves the anomaly to the next phase of the lifecycle), anomalies originated by the user, anomalies the user has addressed, and custom queries that can be saved for future use. Access controls exist depending on a user's role as system administrator, project administrator, user, or developer, and then, further by association with user, project, subsystem, company, or item with provisions for business-to-business exclusions, limitations on access according to the covert or overt nature of a given project, all with multiple layers of filtration, as needed. Reporting of metrics is built in. There is a provision for proxy access (in which the user may choose to grant one or more other users to view screens and perform actions as though they were the user, during any part of a tracking life cycle - especially useful during tight build schedules and vacations to keep things moving). The system also provides users the ability to have an anomaly link to or notify other systems, including QA Inspection Reports, Safety, GIDEP (Government-Industry Data Exchange Program

  13. [361 million problems].

    PubMed

    Livi Bacci, M

    1990-01-01

    changing from the basic subsistence and energy of Malthus's day, as are the factors of election and adaptation. In an increasingly interdependent world, the link between production and consumption of natural resources has become less obvious, so that signs of dangerous imbalances between population and resources may be overlooked. But the demographic problems of 1 region will increasingly affect all other regions. PMID:12316837

  14. The Association between Attention Problems and Internalizing and Externalizing Problems: The Mediating Role of Peer Problems

    ERIC Educational Resources Information Center

    Yip, Vania T.; Ang, Rebecca P.; Ooi, Yoon Phaik; Fung, Daniel S. S.; Mehrotra, Kala; Sung, Min; Lim, Choon Guan

    2013-01-01

    Background: The high prevalence of attention problems in children warrants concern, as it is a risk factor for internalizing and externalizing problems. There lies a need to understand possible factors that may mediate this link so that interventions may be targeted to alleviate these mediators and interrupt the link between attention problems and…

  15. Inverse problem in hydrogeology

    NASA Astrophysics Data System (ADS)

    Carrera, Jesús; Alcolea, Andrés; Medina, Agustín; Hidalgo, Juan; Slooten, Luit J.

    2005-03-01

    The state of the groundwater inverse problem is synthesized. Emphasis is placed on aquifer characterization, where modelers have to deal with conceptual model uncertainty (notably spatial and temporal variability), scale dependence, many types of unknown parameters (transmissivity, recharge, boundary conditions, etc.), nonlinearity, and often low sensitivity of state variables (typically heads and concentrations) to aquifer properties. Because of these difficulties, calibration cannot be separated from the modeling process, as it is sometimes done in other fields. Instead, it should be viewed as one step in the process of understanding aquifer behavior. In fact, it is shown that actual parameter estimation methods do not differ from each other in the essence, though they may differ in the computational details. It is argued that there is ample room for improvement in groundwater inversion: development of user-friendly codes, accommodation of variability through geostatistics, incorporation of geological information and different types of data (temperature, occurrence and concentration of isotopes, age, etc.), proper accounting of uncertainty, etc. Despite this, even with existing codes, automatic calibration facilitates enormously the task of modeling. Therefore, it is contended that its use should become standard practice. L'état du problème inverse des eaux souterraines est synthétisé. L'accent est placé sur la caractérisation de l'aquifère, où les modélisateurs doivent jouer avec l'incertitude des modèles conceptuels (notamment la variabilité spatiale et temporelle), les facteurs d'échelle, plusieurs inconnues sur différents paramètres (transmissivité, recharge, conditions aux limites, etc.), la non linéarité, et souvent la sensibilité de plusieurs variables d'état (charges hydrauliques, concentrations) des propriétés de l'aquifère. A cause de ces difficultés, le calibrage ne peut êtreséparé du processus de modélisation, comme c'est le

  16. Emerging drug problems in Asia

    PubMed Central

    Bart, Gavin

    2014-01-01

    This session, “Emerging Drug Problems in Asia,” focused on emerging drug problems in Asia. Dr. Juana Tomás-Rosselló discussed “East and Southeast Asia: Emerging Drug Problems and Response” and Dr. Wei J. Chen discussed “Ketamine Use among Regular Tobacco and Alcohol Users as Revealed by Respondent Driven Sampling in Taipei: Prevalence, Expectancy, and Users' Risky Decision Making.” PMID:25267884

  17. Student Constructs of Mathematical Problems: Problem Types, Achievement and Gender

    ERIC Educational Resources Information Center

    Chiu, Mei-Shiu; Yeh, Huei-Ming; Whitebread, David

    2014-01-01

    This study aims to understand students' constructs regarding mathematical problems. Fifty-one Taiwanese primary students' constructs are elicited using interviews with the repertory grid technique based on their responses to creative and non-creative problems. The results of qualitative data analysis show that students' initial constructs can be…

  18. Problem Effectiveness in a Course Using Problem-Based Learning.

    ERIC Educational Resources Information Center

    Dolmans, Diana H. J. M.

    1993-01-01

    A University of Limburg (Netherlands) medical school study investigated the relationship between student-generated learning issues and faculty instructional objectives (i.e., the effectiveness of the problems posed) in a problem-centered obstetrics and child development curriculum. Subjects were 120 students and 12 faculty. Results indicated…

  19. The generalized pole assignment problem. [dynamic output feedback problems

    NASA Technical Reports Server (NTRS)

    Djaferis, T. E.; Mitter, S. K.

    1979-01-01

    Two dynamic output feedback problems for a linear, strictly proper system are considered, along with their interrelationships. The problems are formulated in the frequency domain and investigated in terms of linear equations over rings of polynomials. Necessary and sufficient conditions are expressed using genericity.

  20. The Problem of "The Problem with Educational Research"

    ERIC Educational Resources Information Center

    McWilliam, Erica; Lee, Alison

    2006-01-01

    This paper takes up the question of the way in which "the problem with educational research" is represented. It takes as its point of departure two recent views on "the problem"--one expressed by an educational journalist and one presented by the Australian Council of Deans of Education. It locates these within a larger frame of international…

  1. Pet Problems at Home: Pet Problems in the Community.

    ERIC Educational Resources Information Center

    Soltow, Willow

    1984-01-01

    Discusses problems of pets in the community, examining the community's role related to disruptive pets and pet overpopulation. Also discusses pet problems at home, offering advice on selecting a pet, meeting a pet's needs, and disciplining pets. Includes a list of books, films/filmstrips, teaching materials, and various instructional strategies.…

  2. Parent Problem Solving: Analysis of Problem Solving in Parenthood Transition.

    ERIC Educational Resources Information Center

    Alpert, Judith L.; And Others

    The general purpose of this study was to explore the possibility of adapting the Means-Ends Problem-Solving procedure (MEPS) to the investigation of the individual's transition to parenthood. Specific purposes were to determine (1) the internal consistency of the Parent Problem-Solving Scale (PPSS), of its subclasses, and of a combined subscale;…

  3. Problem Solvers: Problem--Jesse's Train

    ERIC Educational Resources Information Center

    James, Julie; Steimle, Alice

    2014-01-01

    Persevering in problem solving and constructing and critiquing mathematical arguments are some of the mathematical practices included in the Common Core State Standards for Mathematics (CCSSI 2010). To solve unfamiliar problems, students must make sense of the situation and apply current knowledge. Teachers can present such opportunities by…

  4. Haplotyping Problem, A Clustering Approach

    SciTech Connect

    Eslahchi, Changiz; Sadeghi, Mehdi; Pezeshk, Hamid; Kargar, Mehdi; Poormohammadi, Hadi

    2007-09-06

    Construction of two haplotypes from a set of Single Nucleotide Polymorphism (SNP) fragments is called haplotype reconstruction problem. One of the most popular computational model for this problem is Minimum Error Correction (MEC). Since MEC is an NP-hard problem, here we propose a novel heuristic algorithm based on clustering analysis in data mining for haplotype reconstruction problem. Based on hamming distance and similarity between two fragments, our iterative algorithm produces two clusters of fragments; then, in each iteration, the algorithm assigns a fragment to one of the clusters. Our results suggest that the algorithm has less reconstruction error rate in comparison with other algorithms.

  5. The PPP: Problem Panel Project.

    ERIC Educational Resources Information Center

    Crawford, Russell K.

    The Problem Panel Project is an instructor-developed, one-semester course in contemporary problems. Based on the inquiry approach, the course is structured for independent research and group work and requires no traditionally-structured daily lesson plans. The course is divided into six procedural points. First, students decide which contemporary…

  6. Historical problem areas lessons learned

    NASA Technical Reports Server (NTRS)

    Sackheim, Bob; Fester, Dale A.

    1991-01-01

    Historical problem areas in space transportation propulsion technology are identified in viewgraph form. Problem areas discussed include materials compatibility, contamination, pneumatic/feed system flow instabilities, instabilities in rocket engine combustion and fuel sloshing, exhaust plume interference, composite rocket nozzle failure, and freeze/thaw damage.

  7. Problem Solving vis Soap Bubbles

    ERIC Educational Resources Information Center

    Bader, William A.

    1975-01-01

    Describes the use of a scientific phenomenon related to the concept of surface tension as an intriguing vehicle to direct attention to useful problem solving techniques. The need for a definite building process in attempts to solve mathematical problems is stressed. (EB)

  8. School Discipline: Problems Effecting Solutions.

    ERIC Educational Resources Information Center

    Heitzman, Andrew J.; Wiley, David B.

    1987-01-01

    Failure to solve school discipline problems is attributed to four factors: school district priorities, unclear problem dimensions, inadequate teacher training, and flaws in teacher/ administrator applied psychology. Psychological approaches that provide systems to control student behavior are described, including biophysical, interactionist, and…

  9. A Problem on Optimal Transportation

    ERIC Educational Resources Information Center

    Cechlarova, Katarina

    2005-01-01

    Mathematical optimization problems are not typical in the classical curriculum of mathematics. In this paper we show how several generalizations of an easy problem on optimal transportation were solved by gifted secondary school pupils in a correspondence mathematical seminar, how they can be used in university courses of linear programming and…

  10. The Cereal Box Problem Revisited.

    ERIC Educational Resources Information Center

    Wilkins, Jesse L. M.

    1999-01-01

    Investigates the cereal box problem using both an experimental and theoretical framework, and Monte Carlo methods. Using empirical data, students can discover patterns and relationships that help them understand the origin of the theoretical solution to the problem. Contains 17 references. (Author/ASK)

  11. Contextual Problem Solving Model Origination

    ERIC Educational Resources Information Center

    Ernst, Jeremy V.

    2009-01-01

    Problem solving has become a central focus of instructional activity in technology education classrooms at all levels (Boser, 1993). Impact assessment considerations incorporating society, culture, and economics are factors that require high-level deliberation involving critical thinking and the implementation of problem solving strategy. The…

  12. Difficulties in Genetics Problem Solving.

    ERIC Educational Resources Information Center

    Tolman, Richard R.

    1982-01-01

    Examined problem-solving strategies of 30 high school students as they solved genetics problems. Proposes a new sequence of teaching genetics based on results: meiosis, sex chromosomes, sex determination, sex-linked traits, monohybrid and dihybrid crosses (humans), codominance (humans), and Mendel's pea experiments. (JN)

  13. Pen Pals: Practicing Problem Solving

    ERIC Educational Resources Information Center

    Lampe, Kristen A.; Uselmann, Linda

    2008-01-01

    This article describes a semester-long pen-pal project in which preservice teachers composed mathematical problems and the middle school students worked for solutions. The college students assessed the solution and the middle school students provided feedback regarding the problem itself. (Contains 6 figures.)

  14. Revised Behavior Problem Checklist (RBPC).

    ERIC Educational Resources Information Center

    Simpson, Robert G.

    1990-01-01

    The Revised Behavior Problem Checklist is used to screen for behavior disorders in K-12 students, develop clinical diagnoses, classify juvenile offenders, and evaluate psychological and pharmacological interventions. The checklist addresses conduct disorder, socialized aggression, attention problems-immaturity, and anxiety-withdrawal. This paper…

  15. Learning Impasses in Problem Solving

    NASA Technical Reports Server (NTRS)

    Hodgson, J. P. E.

    1992-01-01

    Problem Solving systems customarily use backtracking to deal with obstacles that they encounter in the course of trying to solve a problem. This paper outlines an approach in which the possible obstacles are investigated prior to the search for a solution. This provides a solution strategy that avoids backtracking.

  16. NCHEMS IEP: Problems and Consequences.

    ERIC Educational Resources Information Center

    Cox, Robert; Turrisi, Ilona

    Problems with the Information Exchange Procedures (IEP) developed by the National Center for Higher Education Management Systems are discussed. IEP procedures analyze student records, faculty effort, and annual expenditures. The particular approach taken in the analysis of the student faculty relationship has important theoretical problems, is too…

  17. Representations of an Osmosis Problem.

    ERIC Educational Resources Information Center

    Zuckerman, June Trop

    1998-01-01

    Explores whether students with several years of high school science are able to represent an osmosis problem correctly. The study problem features a typical osmotic system with students expected to make a graph to show how the solution level in the stem of the funnel changes over time. (DDR)

  18. Classroom Management: Problems and Solutions.

    ERIC Educational Resources Information Center

    Gordon, Debra G.

    2001-01-01

    Focuses on classroom management in the music classroom. Discusses why a management system is important and how to meet student needs. Addresses types of behavior problems and solutions for four levels of problems related to student behavior. Explores the importance of proactive management on the part of the music teacher. (CMK)

  19. Problem Solving, Scaffolding and Learning

    ERIC Educational Resources Information Center

    Lin, Shih-Yin

    2012-01-01

    Helping students to construct robust understanding of physics concepts and develop good solving skills is a central goal in many physics classrooms. This thesis examine students' problem solving abilities from different perspectives and explores strategies to scaffold students' learning. In studies involving analogical problem solving…

  20. Creative Thinking and Problem Solving.

    ERIC Educational Resources Information Center

    Lacy, Grace

    The booklet considers the nature of creativity in children and examines classroom implications. Among the topics addressed are the following: theories about creativity; research; developments in brain research; the creative process; creative problem solving; the Structure of Intellect Problem Solving (SIPS) model; a rationale for creativity in the…

  1. Readiness for Solving Story Problems.

    ERIC Educational Resources Information Center

    Dunlap, William F.

    1982-01-01

    Readiness activities are described which are designed to help learning disabled (LD) students learn to perform computations in story problems. Activities proceed from concrete objects to numbers and involve the students in devising story problems. The language experience approach is incorporated with the enactive, iconic, and symbolic levels of…

  2. Problem Behaviors & Tourette Syndrome. Revised.

    ERIC Educational Resources Information Center

    Bruun, Ruth Dowling; And Others

    This pamphlet discusses behavioral problems which are sometimes associated with Tourette Syndrome (TS), along with suggestions for parents to help manage these behaviors. Consideration is given to the following problems: obsessive-compulsive symptoms; attention deficit hyperactivity disorder; aggressive and explosive behaviors; self-injurious…

  3. Problem Based Learning: Mystery Disease.

    ERIC Educational Resources Information Center

    Bohland, Mark A.

    This guide features a problem-based learning (PBL) unit specifically designed for student-centered learning of new and meaningful content on diseases. Students grapple with a complex and changing problem that requires higher level thinking skills in an environment in which students work both individually and in collaboration with others. Includes…

  4. The Problem of Faculty Relocation.

    ERIC Educational Resources Information Center

    Tabachnick, Stephen E.

    1992-01-01

    A faculty move to a new campus can be traumatic, but colleges and universities can take steps to lessen the strain. Solutions to faculty relocation problems should be a standard part of any hiring package, not left to chance and individual negotiation. Some problems are inexpensive and easy to solve. (MSE)

  5. Conduct Problem or Learning Disability?

    ERIC Educational Resources Information Center

    Wright, Loyd S.

    1974-01-01

    Forty-seven third grade boys with conduct problems were administered a battery of tests to determine how many had reading problems and central processing dysfunctions and the correlations between their reading performance and 1) central information processing abilities, 2) race, 3) social class, and 4) maternal employment. (Author/DB)

  6. Geothermal Energy: Prospects and Problems

    ERIC Educational Resources Information Center

    Ritter, William W.

    1973-01-01

    An examination of geothermal energy as a means of increasing the United States power resources with minimal pollution problems. Developed and planned geothermal-electric power installations around the world, capacities, installation dates, etc., are reviewed. Environmental impact, problems, etc. are discussed. (LK)

  7. Problem Solving through Paper Folding

    ERIC Educational Resources Information Center

    Wares, Arsalan

    2014-01-01

    The purpose of this article is to describe a couple of challenging mathematical problems that involve paper folding. These problem-solving tasks can be used to foster geometric and algebraic thinking among students. The context of paper folding makes some of the abstract mathematical ideas involved relatively concrete. When implemented…

  8. How Social Problems Are Born.

    ERIC Educational Resources Information Center

    Glazer, Nathan

    1994-01-01

    Examines how social conditions can become social problems and argues that there are objective ways of determining the scale of a particular problem. The paper supports its argument through examinations of prohibition, the decline in tobacco consumption, and the war on drugs. (GLR)

  9. Is the Drug Problem Soluble?

    ERIC Educational Resources Information Center

    Jonas, Steven

    1989-01-01

    Concludes that the principle drug problems in the United States arise from the use of cigarette tobacco and alcoholic beverages. Identifies a drug culture as the persistent force in society that promotes drug use. Points out that the influence of the primary drug industries inhibit attempts to deal effectively with drug problems. (KO)

  10. The Balance-Scale Problem.

    ERIC Educational Resources Information Center

    Greenwood, Jay, Ed.

    1997-01-01

    Presents the reflections of students on a problem given in May, 1996 issue of this journal in order to share the thinking of middle school students. The problem concerned weighing on a double per balance if given a clump of clay, and a 20-gram and 50-gram balance. (ASK)

  11. Quantitative Reasoning in Problem Solving

    ERIC Educational Resources Information Center

    Ramful, Ajay; Ho, Siew Yin

    2015-01-01

    In this article, Ajay Ramful and Siew Yin Ho explain the meaning of quantitative reasoning, describing how it is used in the to solve mathematical problems. They also describe a diagrammatic approach to represent relationships among quantities and provide examples of problems and their solutions.

  12. The Persistent Problems of Education.

    ERIC Educational Resources Information Center

    Woodring, Paul

    Because discussions of educational problems seem to be retracing the same paths and problems, there is need to identify and define the enduring controversies in education and explore reasons for their currency. These issues are discussed in a historical context. The questions of what sort of education is of most worth and what subjects should be…

  13. Rethinking the American Race Problem.

    ERIC Educational Resources Information Center

    Brooks, Roy L.

    Whereas political inequality was once seen as the key element of the American race problem, today the problem can be seen in terms of social and economic disparities. Three general socioeconomic classes have emerged in the United States, a middle class, a working class, and a poverty-stricken class. The status of African Americans can no longer be…

  14. YOUTH EDUCATION, PROBLEMS, PERSPECTIVES, PROMISES.

    ERIC Educational Resources Information Center

    MUESSIG, RAYMOND H.

    IN AN ANALYSIS OF CONTEMPORARY ADOLESCENT EDUCATION BY SEVEN MEMBERS OF A YEARBOOK COMMITTEE, FIVE PERSPECTIVES--SOCIAL-PHILOSOPHICAL, PSYCHOPHYSICAL, LITERARY, CURRICULAR, AND METHODOLOGICAL--ARE CONSIDERED, AND CONSTRUCTIVE PROPOSALS FOR SOLVING RELATED PROBLEMS ARE SUGGESTED. AN INTRODUCTORY CHAPTER DISCUSSES THE BASIC TEEN-AGE PROBLEM AREAS OF…

  15. Problem Based Learning in Science

    ERIC Educational Resources Information Center

    Pepper, Coral

    2009-01-01

    Problem based learning (PBL) is a recognised teaching and learning strategy used to engage students in deep rather than surface learning. It is also viewed as a successful strategy to align university courses with the real life professional work students are expected to undertake on graduation (Biggs, 2003). Problem based learning is practised…

  16. The Problems of Human Environment.

    ERIC Educational Resources Information Center

    United Nations, New York, NY.

    Presented is a summary of considerations Specialized Agencies within the United Nations have given to the problems of the human environment. Uppermost are the problems of pollution--air, water, noise, marine, radiation, food, pesticide--as well as those of economic and social concern, environmental health, and misuse of the environment. Agencies…

  17. Students' Problem Solving and Justification

    ERIC Educational Resources Information Center

    Glass, Barbara; Maher, Carolyn A.

    2004-01-01

    This paper reports on methods of students' justifications of their solution to a problem in the area of combinatorics. From the analysis of the problem solving of 150 students in a variety of settings from high-school to graduate study, four major forms of reasoning evolved: (1) Justification by Cases, (2) Inductive Argument, (3) Elimination…

  18. The three-body problem.

    PubMed

    Musielak, Z E; Quarles, B

    2014-06-01

    The three-body problem, which describes three masses interacting through Newtonian gravity without any restrictions imposed on the initial positions and velocities of these masses, has attracted the attention of many scientists for more than 300 years. In this paper, we present a review of the three-body problem in the context of both historical and modern developments. We describe the general and restricted (circular and elliptic) three-body problems, different analytical and numerical methods of finding solutions, methods for performing stability analysis and searching for periodic orbits and resonances. We apply the results to some interesting problems of celestial mechanics. We also provide a brief presentation of the general and restricted relativistic three-body problems, and discuss their astronomical applications. PMID:24913140

  19. Ten Problems in Experimental Mathematics

    SciTech Connect

    Bailey, David H.; Borwein, Jonathan M.; Kapoor, Vishaal; Weisstein, Eric

    2004-09-30

    This article was stimulated by the recent SIAM ''100 DigitChallenge'' of Nick Trefethen, beautifully described in a recent book. Indeed, these ten numeric challenge problems are also listed in a recent book by two of present authors, where they are followed by the ten symbolic/numeric challenge problems that are discussed in this article. Our intent was to present ten problems that are characteristic of the sorts of problems that commonly arise in ''experimental mathematics''. The challenge in each case is to obtain a high precision numeric evaluation of the quantity, and then, if possible, to obtain a symbolic answer, ideally one with proof. Our goal in this article is to provide solutions to these ten problems, and in the process present a concise account of how one combines symbolic and numeric computation, which may be termed ''hybrid computation'', in the process of mathematical discovery.

  20. Surface crack problems in plates

    NASA Technical Reports Server (NTRS)

    Joseph, P. F.; Erdogan, F.

    1989-01-01

    The mode I crack problem in plates under membrane loading and bending is reconsidered. The purpose is to examine certain analytical features of the problem further and to provide some new results. The formulation and the results given by the classical and the Reissner plate theories for through and part-through cracks are compared. For surface cracks the three-dimensional finite element solution is used as the basis of comparison. The solution is obtained and results are given for the crack/contact problem in a plate with a through crack under pure bending and for the crack interaction problem. Also, a procedure is developed to treat the problem of subcritical crack growth and to trace the evolution of the propagating crack.

  1. Non-linear potential problems

    NASA Astrophysics Data System (ADS)

    Skerget, P.; Brebbia, C. A.

    In many practical applications of boundary elements, the potential problems may be nonlinear. The use of Kirchoff's transform provides an approach to convert a nonlinear material problem into a linear one. A description of several different shape functions to define the conductivity is presented. Attention is given to the type of integral equations which are obtained if the Kirchoff's transform is applied for nonlinear material in the presence of mixed boundary conditions. The integral formulation for nonlinear radiation boundary conditions with and without potential dependent conductivity is also considered. For steady heat conduction problems with constant conductivity a boundary integral equation relating boundary values for temperatures (or potentials) and its normal derivatives over the boundary can be obtained. Applications which concern the solution of steady state conduction problems are investigated. The problems are related to a hollow cylinder, a nuclear reactor pressure vessel, and an industrial furnace.

  2. Development of adolescent problem behavior.

    PubMed

    Ary, D V; Duncan, T E; Biglan, A; Metzler, C W; Noell, J W; Smolkowski, K

    1999-04-01

    The developmental model of adolescent antisocial behavior advanced by Patterson and colleagues (e.g., Patterson, Reid, & Dishion, 1992) appears to generalize the development of a diverse set of problem behaviors. Structural equation modeling methods were applied to 18-month longitudinal data from 523 adolescents. The problem behavior construct included substance use, antisocial behavior, academic failure, and risky sexual behavior. Families with high levels of conflict were less likely to have high levels of parent-child involvement. Such family conditions resulted in less adequate parental monitoring of adolescent behavior, making associations with deviant peers more likely. Poor parental monitoring and associations with deviant peers were strong predictors of engagement in problem behavior. These constructs accounted for 46% of the variance in problem behavior. Although association with deviant peers was the most proximal social influence on problem behavior, parental monitoring and family factors (conflict and involvement) were key parenting practices that influenced this developmental process. PMID:10400060

  3. 30 Years of Wahba's Problem

    NASA Technical Reports Server (NTRS)

    Markley, F. Landis

    1999-01-01

    This article discusses a problem proposed by Grace Wahba: Find the orthogonal matrix A with determinant +1 that minimizes the loss function L(A) is identical with the 1/2(summation from i( a(sub i) * absolute value of (b(sub i)- Ar(sub i))squared). where {b(sub i)} is a set of unit vectors measured in a spacecraft's body frame, {r(sub i)} e the corresponding unit vectors in a reference frame and {a(sub i) are non-negative weights). The orthogonal Procrustes problem is to find the orthogonal matrix A that is closest to B in the sense of the Fobenius norm, so that Wahba's Problem is equivalent to the orthogonal Procrustes problem with the provision that the determinant of A must be +1. The article reviews various solutions to this problem and the implementations of the various solutions.

  4. Generating Problems from Problems and Solutions from Solutions

    ERIC Educational Resources Information Center

    Arcavi, Abraham; Resnick, Zippora

    2008-01-01

    This article describes a geometrical solution to a problem that is usually solved geometrically as an example of how alternative solutions may enrich the teaching and learning of mathematics. (Contains 11 figures.)

  5. Problem solving stages in the five square problem.

    PubMed

    Fedor, Anna; Szathmáry, Eörs; Öllinger, Michael

    2015-01-01

    According to the restructuring hypothesis, insight problem solving typically progresses through consecutive stages of search, impasse, insight, and search again for someone, who solves the task. The order of these stages was determined through self-reports of problem solvers and has never been verified behaviorally. We asked whether individual analysis of problem solving attempts of participants revealed the same order of problem solving stages as defined by the theory and whether their subjective feelings corresponded to the problem solving stages they were in. Our participants tried to solve the Five-Square problem in an online task, while we recorded the time and trajectory of their stick movements. After the task they were asked about their feelings related to insight and some of them also had the possibility of reporting impasse while working on the task. We found that the majority of participants did not follow the classic four-stage model of insight, but had more complex sequences of problem solving stages, with search and impasse recurring several times. This means that the classic four-stage model is not sufficient to describe variability on the individual level. We revised the classic model and we provide a new model that can generate all sequences found. Solvers reported insight more often than non-solvers and non-solvers reported impasse more often than solvers, as expected; but participants did not report impasse more often during behaviorally defined impasse stages than during other stages. This shows that impasse reports might be unreliable indicators of impasse. Our study highlights the importance of individual analysis of problem solving behavior to verify insight theory. PMID:26300794

  6. Problem solving stages in the five square problem

    PubMed Central

    Fedor, Anna; Szathmáry, Eörs; Öllinger, Michael

    2015-01-01

    According to the restructuring hypothesis, insight problem solving typically progresses through consecutive stages of search, impasse, insight, and search again for someone, who solves the task. The order of these stages was determined through self-reports of problem solvers and has never been verified behaviorally. We asked whether individual analysis of problem solving attempts of participants revealed the same order of problem solving stages as defined by the theory and whether their subjective feelings corresponded to the problem solving stages they were in. Our participants tried to solve the Five-Square problem in an online task, while we recorded the time and trajectory of their stick movements. After the task they were asked about their feelings related to insight and some of them also had the possibility of reporting impasse while working on the task. We found that the majority of participants did not follow the classic four-stage model of insight, but had more complex sequences of problem solving stages, with search and impasse recurring several times. This means that the classic four-stage model is not sufficient to describe variability on the individual level. We revised the classic model and we provide a new model that can generate all sequences found. Solvers reported insight more often than non-solvers and non-solvers reported impasse more often than solvers, as expected; but participants did not report impasse more often during behaviorally defined impasse stages than during other stages. This shows that impasse reports might be unreliable indicators of impasse. Our study highlights the importance of individual analysis of problem solving behavior to verify insight theory. PMID:26300794

  7. Optimization and geophysical inverse problems

    SciTech Connect

    Barhen, J.; Berryman, J.G.; Borcea, L.; Dennis, J.; de Groot-Hedlin, C.; Gilbert, F.; Gill, P.; Heinkenschloss, M.; Johnson, L.; McEvilly, T.; More, J.; Newman, G.; Oldenburg, D.; Parker, P.; Porto, B.; Sen, M.; Torczon, V.; Vasco, D.; Woodward, N.B.

    2000-10-01

    A fundamental part of geophysics is to make inferences about the interior of the earth on the basis of data collected at or near the surface of the earth. In almost all cases these measured data are only indirectly related to the properties of the earth that are of interest, so an inverse problem must be solved in order to obtain estimates of the physical properties within the earth. In February of 1999 the U.S. Department of Energy sponsored a workshop that was intended to examine the methods currently being used to solve geophysical inverse problems and to consider what new approaches should be explored in the future. The interdisciplinary area between inverse problems in geophysics and optimization methods in mathematics was specifically targeted as one where an interchange of ideas was likely to be fruitful. Thus about half of the participants were actively involved in solving geophysical inverse problems and about half were actively involved in research on general optimization methods. This report presents some of the topics that were explored at the workshop and the conclusions that were reached. In general, the objective of a geophysical inverse problem is to find an earth model, described by a set of physical parameters, that is consistent with the observational data. It is usually assumed that the forward problem, that of calculating simulated data for an earth model, is well enough understood so that reasonably accurate synthetic data can be generated for an arbitrary model. The inverse problem is then posed as an optimization problem, where the function to be optimized is variously called the objective function, misfit function, or fitness function. The objective function is typically some measure of the difference between observational data and synthetic data calculated for a trial model. However, because of incomplete and inaccurate data, the objective function often incorporates some additional form of regularization, such as a measure of smoothness

  8. Civil law problems and morbidity

    PubMed Central

    Pleasence, P; Balmer, N; Buck, A; O'Grady, A; Genn, H

    2004-01-01

    Study objective: In the United Kingdom, recognition of the links between social and health problems has led to government initiatives such as health action zones. The principles of civil law apply to many types of social problem, and the civil justice system provides one means through which they can be tackled. However, little research has been undertaken into the particular links between problems to which civil legal principles and processes can be applied and morbidity. This study examines these links, and the role of legal advice and services in preventing ill health. Design: This study examined survey respondents' self reports of longstanding illness/disability and experience of 18 problems to which legal principles can be applied. Setting: A random national survey conducted across England and Wales. Participants: 5611 adults drawn from 3348 residential households. Main results: Significant associations were found between illness/disability and 13 of the problem types. Moreover, experience of greater numbers of problems increased the likelihood of reported illness/disability. In attempting to resolve problems respondents' health also frequently suffered. Conclusions: This study highlights the contribution that public legal education and legal advice can make to the promotion of public health, and the importance of further integration of health and civil justice initiatives through health action zones, community legal service partnerships, etc, to further this end. PMID:15194714

  9. Periodically specified satisfiability problems: An alternative to domino problems

    SciTech Connect

    Marathe, M.V.; Rosenkrantz, D.J.; Stearns, R.E.

    1997-02-01

    The authors characterize the complexities of several basic generalized CNF satisfiability problems SAT(S), when instances are specified using various kinds of 1- and 2-dimensional periodic specifications. They outline how this characterization can be used to prove a number of new hardness results for the complexity classes DSPACE(n), NSPACE(n), DEXPTIME, NEXPTIME, EXPSPACE etc. The hardness results presented significantly extend the known hardness results for periodically specified problems. Several advantages are outlined of the use of periodically specified satisfiability problems over the use of domino problems in proving both hardness and easiness results. As one corollary, the authors show that a number of basic NP-hard problems become EXPSPACE-hard when inputs are represented using 1-dimensional infinite periodic wide specifications. This answers a long standing open question posed by Orlin. The results can also be used as starting points for proving the hardness of a number of combinatorial problems when instances are specified succinctly using various succinct specifications. These results significantly extend the results of earlier research in this area.

  10. The Soccer-Ball Problem

    NASA Astrophysics Data System (ADS)

    Hossenfelder, Sabine

    2014-07-01

    The idea that Lorentz-symmetry in momentum space could be modified but still remain observer-independent has received quite some attention in the recent years. This modified Lorentz-symmetry, which has been argued to arise in Loop Quantum Gravity, is being used as a phenomenological model to test possibly observable effects of quantum gravity. The most pressing problem in these models is the treatment of multi-particle states, known as the 'soccer-ball problem'. This article briefly reviews the problem and the status of existing solution attempts.

  11. General aviation IFR operational problems

    NASA Technical Reports Server (NTRS)

    Bolz, E. H.; Eisele, J. E.

    1979-01-01

    Operational problems of general aviation IFR operators (particularly single pilot operators) were studied. Several statistical bases were assembled and utilized to identify the more serious problems and to demonstrate their magnitude. These bases include official activity projections, historical accident data and delay data, among others. The GA operating environment and cockpit environment were analyzed in detail. Solutions proposed for each of the problem areas identified are based on direct consideration of currently planned enhancements to the ATC system, and on a realistic assessment of the present and future limitations of general aviation avionics. A coordinated set of research program is suggested which would provide the developments necessary to implement the proposed solutions.

  12. Robot, computer problem solving system

    NASA Technical Reports Server (NTRS)

    Becker, J. D.

    1972-01-01

    The development of a computer problem solving system is reported that considers physical problems faced by an artificial robot moving around in a complex environment. Fundamental interaction constraints with a real environment are simulated for the robot by visual scan and creation of an internal environmental model. The programming system used in constructing the problem solving system for the simulated robot and its simulated world environment is outlined together with the task that the system is capable of performing. A very general framework for understanding the relationship between an observed behavior and an adequate description of that behavior is included.

  13. Problems in nonlinear resistive MHD

    SciTech Connect

    Turnbull, A.D.; Strait, E.J.; La Haye, R.J.; Chu, M.S.; Miller, R.L.

    1998-12-31

    Two experimentally relevant problems can relatively easily be tackled by nonlinear MHD codes. Both problems require plasma rotation in addition to the nonlinear mode coupling and full geometry already incorporated into the codes, but no additional physics seems to be crucial. These problems discussed here are: (1) nonlinear coupling and interaction of multiple MHD modes near the B limit and (2) nonlinear coupling of the m/n = 1/1 sawtooth mode with higher n gongs and development of seed islands outside q = 1.

  14. Imbalance problem in community detection

    NASA Astrophysics Data System (ADS)

    Sun, Peng Gang

    2016-09-01

    Community detection gives us a simple way to understand complex networks' structures. However, there is an imbalance problem in community detection. This paper first introduces the imbalance problem and then proposes a new measure to alleviate the imbalance problem. In addition, we study two variants of the measure and further analyze the resolution scale of community detection. Finally, we compare our approach with some state of the art methods on random networks as well as real-world networks for community detection. Both the theoretical analysis and the experimental results show that our approach achieves better performance for community detection. We also find that our approach tends to separate densely connected subgroups preferentially.

  15. The unsolved problems of neuroscience

    PubMed Central

    Adolphs, Ralph

    2015-01-01

    Some problems in neuroscience are nearly solved. For others, solutions are decades away. The current pace of advances in methods forces us to take stock, to ask where we are going, and what we should research next. PMID:25703689

  16. The Math Contest Candidate's Problem.

    ERIC Educational Resources Information Center

    Frank, Kenneth W.

    1985-01-01

    A simply posed problem suitable for a class studying summations and series, a class in elementary computer programing, a high school mathematics club, or an individual study project is given, with solution and challenges. (MNS)

  17. Systems management techniques and problems

    NASA Technical Reports Server (NTRS)

    1971-01-01

    Report is reviewed which discusses history and trends of systems management, its basic principles, and nature of problems that lend themselves to systems approach. Report discusses systems engineering as applied to weapons acquisition, ecology, patient monitoring, and retail merchandise operations.

  18. A Few Problems Involving Scale.

    ERIC Educational Resources Information Center

    McKillip, William D.; Kay, Cynthia Stinnette

    1985-01-01

    Some applications of ratio and proportion to scale drawing involving geometric figures are given. The activities or problems concern the earth and space, scale speeds, and the earth-moon system. (MNS)

  19. Problems in Recording the Electrocardiogram.

    ERIC Educational Resources Information Center

    Webster, John G.

    The unwanted signals that arise in electrocardiography are discussed. A technical background of electrocardiography is given, along with teaching techniques that educate students of medical instrumentation to solve the problems caused by these signals. (MJH)

  20. Enteral nutrition - child - managing problems

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000164.htm Enteral nutrition - child - managing problems To use the sharing features ... trouble breathing, call 911. References Mcclave SA. Enteral nutrition. In: Goldman L, Schafer AI, eds. Goldman's Cecil ...

  1. Quantum Computing: Solving Complex Problems

    ScienceCinema

    DiVincenzo, David [IBM Watson Research Center

    2009-09-01

    One of the motivating ideas of quantum computation was that there could be a new kind of machine that would solve hard problems in quantum mechanics. There has been significant progress towards the experimental realization of these machines (which I will review), but there are still many questions about how such a machine could solve computational problems of interest in quantum physics. New categorizations of the complexity of computational problems have now been invented to describe quantum simulation. The bad news is that some of these problems are believed to be intractable even on a quantum computer, falling into a quantum analog of the NP class. The good news is that there are many other new classifications of tractability that may apply to several situations of physical interest.

  2. Multiple Solutions Involving Geoboard Problems.

    ERIC Educational Resources Information Center

    Smith, Lyle R.

    1993-01-01

    Illustrates various methods to determine the perimeter and area of triangles and polygons formed on the geoboard. Methods utilize algebraic techniques, trigonometry, geometric theorems, and analytic geometry to solve problems and connect a variety of mathematical concepts. (MDH)

  3. Corrosion Problems in Absorption Chillers

    ERIC Educational Resources Information Center

    Stetson, Bruce

    1978-01-01

    Absorption chillers use a lithium bromide solution as the medium of absorption and water as the refrigerant. Discussed are corrosion and related problems, tests and remedies, and cleaning procedures. (Author/MLF)

  4. Special Medical Problems of Athletes.

    ERIC Educational Resources Information Center

    Couch, Joan M.

    1987-01-01

    This article addresses the situations in which athletes with special needs and considerations participate in sports. The health problems discussed are diabetes mellitus, exercise-induced asthma, exercise-induced anaphylaxis, and epilepsy. (MT)

  5. Solving a problem by analogy

    NASA Astrophysics Data System (ADS)

    Easton, Don

    1999-03-01

    This note is a description of a student solution to a problem. I found the solution exciting because it exemplifies the kind of solution by analogy that Feynman describes in The Feynman Lectures on Physics.

  6. Late Blooming or Language Problem?

    MedlinePlus

    ... and Swallowing / Disorders and Diseases Late Blooming or Language Problem? Parents are smart. They listen to their ... or not their child is developing speech and language at a normal rate. If parents think that ...

  7. Quantum Computing: Solving Complex Problems

    SciTech Connect

    DiVincenzo, David

    2007-04-12

    One of the motivating ideas of quantum computation was that there could be a new kind of machine that would solve hard problems in quantum mechanics. There has been significant progress towards the experimental realization of these machines (which I will review), but there are still many questions about how such a machine could solve computational problems of interest in quantum physics. New categorizations of the complexity of computational problems have now been invented to describe quantum simulation. The bad news is that some of these problems are believed to be intractable even on a quantum computer, falling into a quantum analog of the NP class. The good news is that there are many other new classifications of tractability that may apply to several situations of physical interest.

  8. Quantum Computing: Solving Complex Problems

    SciTech Connect

    DiVincenzo, David

    2007-04-11

    One of the motivating ideas of quantum computation was that there could be a new kind of machine that would solve hard problems in quantum mechanics. There has been significant progress towards the experimental realization of these machines (which I will review), but there are still many questions about how such a machine could solve computational problems of interest in quantum physics. New categorizations of the complexity of computational problems have now been invented to describe quantum simulation. The bad news is that some of these problems are believed to be intractable even on a quantum computer, falling into a quantum analog of the NP class. The good news is that there are many other new classifications of tractability that may apply to several situations of physical interest.

  9. The Mind-Body Problem.

    ERIC Educational Resources Information Center

    Fodor, Jerry A.

    1981-01-01

    Describes several different philosophies of mind with each philosophy's explanation of the mind-body problem. Philosophies discussed include dualism, materialism, functionalism, radical behaviorism, logical behaviorism and central-state identity. (DS)

  10. Risks for Heart Valve Problems

    MedlinePlus

    ... had rheumatic fever or a case of infective endocarditis are at greater risk for heart valve problems. ... needed before dental procedures to help protect against endocarditis . You should discuss your individual risk and the ...

  11. Surrogate Guderley Test Problem Definition

    SciTech Connect

    Ramsey, Scott D.; Shashkov, Mikhail J.

    2012-07-06

    The surrogate Guderley problem (SGP) is a 'spherical shock tube' (or 'spherical driven implosion') designed to ease the notoriously subtle initialization of the true Guderley problem, while still maintaining a high degree of fidelity. In this problem (similar to the Guderley problem), an infinitely strong shock wave forms and converges in one-dimensional (1D) cylindrical or spherical symmetry through a polytropic gas with arbitrary adiabatic index {gamma}, uniform density {rho}{sub 0}, zero velocity, and negligible pre-shock pressure and specific internal energy (SIE). This shock proceeds to focus on the point or axis of symmetry at r = 0 (resulting in ostensibly infinite pressure, velocity, etc.) and reflect back out into the incoming perturbed gas.

  12. Developmental Problems and Dental Morphology

    ERIC Educational Resources Information Center

    Goodwin, William C., Jr.; Erickson, Marilyn T.

    1973-01-01

    Ninety-five subjects (mean age 55 months) with mental retardation, learning disabilities, and/or minimal brain dysfunction and 47 control subjects (mean age 46 months) were compared to determine the relationship between developmental problems and dental morphology. (Author)

  13. Problem Solving with General Semantics.

    ERIC Educational Resources Information Center

    Hewson, David

    1996-01-01

    Discusses how to use general semantics formulations to improve problem solving at home or at work--methods come from the areas of artificial intelligence/computer science, engineering, operations research, and psychology. (PA)

  14. Nervous System Problems and Dementia

    MedlinePlus

    ... especially when compared to reflexes in the knees. Magnetic Resonance Imaging (MRI,) a radiologic procedure, may show abnormalities in ... later stages of HIV disease. However, problems with memory can show up even in people with no ...

  15. The continuation inverse problem revisited

    NASA Astrophysics Data System (ADS)

    Huestis, Stephen P.

    1998-06-01

    The non-uniqueness of the continuation of a finite collection of harmonic potential field data to a level surface in the source-free region forces its treatment as an inverse problem. A formalism is proposed for the construction of continuation functions which are extremal by various measures. The problem is cast in such a form that the inverse problem solution is the potential function on the lowest horizontal surface above all sources, serving as the boundary function for the Dirichlet problem in the upper half-plane. The desired continuation, at the higher level of interest, must then be in the range of the upward continuation operator acting on this boundary function, rather than being allowed the full freedom of itself being part of a Dirichlet problem boundary function. Extremal solutions minimize non-linear functionals of the continuation function, which are re-expressed as different functionals of the boundary function. A crux of the method is that there is no essential distinction between the upward and downward continuation inverse problems to levels above or below data locations. Casting the optimization as a Lagrange multiplier problem leads to an integral equation for the boundary function, which is readily solved in the Fourier domain for a certain class of functionals. The desired extremal continuation is then given by upward continuation. It is found that for some functionals, application of the Lagrange multiplier theorem requires a further restriction on the set of allowable boundary functions: bandlimitedness is a natural choice for the continuation problem. With this imposition, the theory is developed in detail for semi-norm functionals penalizing departure from a constant potential, in the 2-norm and Sobelev norm senses, and illustrated by application for a small synthetic Deep Tow magnetic field data set.

  16. Noise: a forgotten environmental problem

    SciTech Connect

    Kloos, J.B.

    1980-01-01

    Highway traffic noise is a serious problem for communities. The traffic noise can be lessened by source controls. The impact of the noise can be mitigated with barriers built along heavily traveled roads. However, the most promising long-range solution is noise compatible land use planning at the local level. Low cost methods are available to prevent noise problems from ever occuring. The Federal Highway Administration is attempting to encourage local officials to use these methods.

  17. Families and Pediatric Feeding Problems

    ERIC Educational Resources Information Center

    Martorana, Pamela; Bove, Kelly; Scarcelli, Melissa

    2008-01-01

    When a child is born with a feeding and/or swallowing problem, it affects the entire family. Parents, mothers specifically, internalize the problem and come to believe it is due to something they've done. Families are put on an emotional rollercoaster with the ups and downs being dependant on how much the child has eaten that day. In this article,…

  18. Coulomb problem for vector bosons

    SciTech Connect

    Kuchiev, M.Yu.; Flambaum, V.V.

    2006-05-01

    The Coulomb problem for vector bosons W{sup {+-}} incorporates a well-known difficulty; the charge of the boson localized in a close vicinity of the attractive Coulomb center proves to be infinite. The paradox is shown to be resolved by the QED vacuum polarization, which brings in a strong effective repulsion that eradicates the infinite charge of the boson on the Coulomb center. This property allows one to define the Coulomb problem for vector bosons properly.

  19. Multilevel techniques for nonelliptic problems

    NASA Technical Reports Server (NTRS)

    Jespersen, D. C.

    1981-01-01

    Multigrid and multilevel methods are extended to the solution of nonelliptic problems. A framework for analyzing these methods is established. A simple nonelliptic problem is given, and it is shown how a multilevel technique can be used for its solution. Emphasis is on smoothness properties of eigenvectors and attention is drawn to the possibility of conditioning the eigensystem so that eigenvectors have the desired smoothness properties.

  20. Diabetes and Sexual and Urologic Problems

    MedlinePlus

    ... Disease, and Other Dental Problems Diabetic Eye Disease Diabetes and Sexual and Urologic Problems Troublesome bladder symptoms ... early onset of these sexual and urologic problems. Diabetes and Sexual Problems Both men and women with ...

  1. The Consistent Vehicle Routing Problem

    SciTech Connect

    Groer, Christopher S; Golden, Bruce; Edward, Wasil

    2009-01-01

    In the small package shipping industry (as in other industries), companies try to differentiate themselves by providing high levels of customer service. This can be accomplished in several ways, including online tracking of packages, ensuring on-time delivery, and offering residential pickups. Some companies want their drivers to develop relationships with customers on a route and have the same drivers visit the same customers at roughly the same time on each day that the customers need service. These service requirements, together with traditional constraints on vehicle capacity and route length, define a variant of the classical capacitated vehicle routing problem, which we call the consistent VRP (ConVRP). In this paper, we formulate the problem as a mixed-integer program and develop an algorithm to solve the ConVRP that is based on the record-to-record travel algorithm. We compare the performance of our algorithm to the optimal mixed-integer program solutions for a set of small problems and then apply our algorithm to five simulated data sets with 1,000 customers and a real-world data set with more than 3,700 customers. We provide a technique for generating ConVRP benchmark problems from vehicle routing problem instances given in the literature and provide our solutions to these instances. The solutions produced by our algorithm on all problems do a very good job of meeting customer service objectives with routes that have a low total travel time.

  2. The three-body problem

    NASA Astrophysics Data System (ADS)

    Marchal, Christian

    Recent research on the theory of perturbations, the analytical approach and the quantitative analysis of the three-body problem have reached a high degree of perfection. The use of electronics has aided developments in quantitative analysis and has helped to disclose the extreme complexity of the set of solutions. This accelerated progress has given new orientation and impetus to the qualitative analysis that is so complementary to the quantitative analysis. The book begins with the various formulations of the three-body problem, the main classical results and the important questions and conjectures involved in this subject. The main part of the book describes the remarkable progress achieved in qualitative analysis which has shed new light on the three-body problem. It deals with questions such as escapes, captures, periodic orbits, stability, chaotic motions, Arnold diffusion, etc. The most recent tests of escape have yielded very impressive results and border very close on the true limits of escape, showing the domain of bounded motions to be much smaller than was expected. An entirely new picture of the three-body problem is emerging, and the book reports on this recent progress. The structure of the solutions for the three-body problem lead to a general conjecture governing the picture of solutions for all Hamiltonian problems. The periodic, quasi-periodic and almost-periodic solutions form the basis for the set of solutions and separate the chaotic solutions from the open solutions.

  3. Conceptual approach to astronomical problems

    NASA Astrophysics Data System (ADS)

    Skvortsov, N. A.; Avvakumova, E. A.; Bryukhov, D. O.; Vovchenko, A. E.; Vol'nova, A. A.; Dluzhnevskaya, O. B.; Kaigorodov, P. V.; Kalinichenko, L. A.; Kniazev, A. Yu.; Kovaleva, D. A.; Malkov, O. Yu.; Pozanenko, A. S.; Stupnikov, S. A.

    2016-01-01

    New technical capabilities have brought about the sweeping growth of the amount of data acquired by the astronomers from observations with different instruments in various parts of the electromagnetic spectrum. We consider conceptual approach to be a promising tool to efficiently deal with these data. It uses problem domain knowledge to formulate the tasks and develop problem-solving algorithms and data analysis methods in terms of domain concepts without reference to particular data sources, and thereby allows solving certain problems in general form. We demonstrate the benefits of conceptual approach by using it to solve problems related to search for secondary photometric standard candidates, determination of galaxy redshifts, creation of a binary and multiple star repository based on inhomogeneous databases, and classification of eclipsing binaries.We formulate and solve these problems over specifications of astronomical knowledge units such as photometric systems, astronomical objects, multiple stars, etc., and define them in terms of the corresponding problem domains independently of the existing data resources.

  4. Approximating random quantum optimization problems

    NASA Astrophysics Data System (ADS)

    Hsu, B.; Laumann, C. R.; Läuchli, A. M.; Moessner, R.; Sondhi, S. L.

    2013-06-01

    We report a cluster of results regarding the difficulty of finding approximate ground states to typical instances of the quantum satisfiability problem k-body quantum satisfiability (k-QSAT) on large random graphs. As an approximation strategy, we optimize the solution space over “classical” product states, which in turn introduces a novel autonomous classical optimization problem, PSAT, over a space of continuous degrees of freedom rather than discrete bits. Our central results are (i) the derivation of a set of bounds and approximations in various limits of the problem, several of which we believe may be amenable to a rigorous treatment; (ii) a demonstration that an approximation based on a greedy algorithm borrowed from the study of frustrated magnetism performs well over a wide range in parameter space, and its performance reflects the structure of the solution space of random k-QSAT. Simulated annealing exhibits metastability in similar “hard” regions of parameter space; and (iii) a generalization of belief propagation algorithms introduced for classical problems to the case of continuous spins. This yields both approximate solutions, as well as insights into the free energy “landscape” of the approximation problem, including a so-called dynamical transition near the satisfiability threshold. Taken together, these results allow us to elucidate the phase diagram of random k-QSAT in a two-dimensional energy-density-clause-density space.

  5. Solving the Tulsa ozone problem

    SciTech Connect

    Wagner, K.K.; Wilson, J.D.; Gibeau, E.

    1998-12-31

    Local governments and interested parties in Tulsa, Oklahoma are planning actions to keep Tulsa in compliance with the ozone ambient air quality standard. Based on recent data Tulsa exceeds the new eight hour average national ambient air quality standard for ozone and occasionally exceeds the previous one hour standard. Currently, Tulsa is in attainment of the former one-hour ozone standard. The first planning step is to integrate the existing information about Tulsa`s ozone problem. Prior studies of Tulsa ozone are reviewed. Tulsa`s recent air quality and meteorological monitoring are evaluated. Emission inventory estimates are assessed. Factors identified with Tulsa`s ozone problem are the transport of ozone and precursor gases, a possible role for biogenic emissions, and a simplistic ozone forecasting method. The integration of information found that current air quality and meteorological monitoring is meager. Observations of volatile organic compounds and NO{sub y} are absent. Prior intensive studies in 1977 and 1985 are more than ten years old and lack relevance to today`s problem. Emission inventory estimates are scarce and uncertain. The current knowledge base was judged inadequate to properly characterize the present ozone problem. Actions are recommended to enlarge the information base to address Tulsa`s ozone problem.

  6. Problems of collisional stellar dynamics

    NASA Astrophysics Data System (ADS)

    Heggie, D. C.

    2011-03-01

    The discovery of dynamical friction was Chandrasekhar's best known contribution to the theory of stellar dynamics, but his work ranged from the few-body problem to the limit of large N (in effect, galaxies). Much of this work was summarised in the text "Principles of Stellar Dynamics" tep{C1942,C1960}, which ranges from a precise calculation of the time of relaxation, through a long analysis of galaxy models, to the behaviour of star clusters in tidal fields. The later edition also includes the work on dynamical friction and related issues. In this review we focus on progress in the collisional aspects of these problems, i.e. those where few-body interactions play a dominant role, and so we omit further discussion of galaxy dynamics. But we try to link Chandrasekhar's fundamental discoveries in collisional problems with the progress that has been made in the 50 years since the publication of the enlarged edition. There is one other such problem to which Chandrasekhar contributed, though the paper in question tep{C1944} was not reprinted in the book. See Section ref{sec:binaries}. For more on the collisionless problems studied by Chandrasekhar, see the paper by N. Wyn Evans (2011) in the present volume.

  7. Computational problems in Arctic Research

    NASA Astrophysics Data System (ADS)

    Petrov, I.

    2016-02-01

    This article is to inform about main problems in the area of Arctic shelf seismic prospecting and exploitation of the Northern Sea Route: simulation of the interaction of different ice formations (icebergs, hummocks, and drifting ice floes) with fixed ice-resistant platforms; simulation of the interaction of icebreakers and ice- class vessels with ice formations; modeling of the impact of the ice formations on the underground pipelines; neutralization of damage for fixed and mobile offshore industrial structures from ice formations; calculation of the strength of the ground pipelines; transportation of hydrocarbons by pipeline; the problem of migration of large ice formations; modeling of the formation of ice hummocks on ice-resistant stationary platform; calculation the stability of fixed platforms; calculation dynamic processes in the water and air of the Arctic with the processing of data and its use to predict the dynamics of ice conditions; simulation of the formation of large icebergs, hummocks, large ice platforms; calculation of ridging in the dynamics of sea ice; direct and inverse problems of seismic prospecting in the Arctic; direct and inverse problems of electromagnetic prospecting of the Arctic. All these problems could be solved by up-to-date numerical methods, for example, using grid-characteristic method.

  8. Problem Solvers: Problem--Area beyond the Formula

    ERIC Educational Resources Information Center

    Dean, Chrystal

    2014-01-01

    In this article, associate professor Chrystal Dean describes how teachers can challenge their upper elementary students' understanding of area beyond a memorized formula. Herein she describes an activity that will show students the "why" behind using A = l × w to solve rectangular area problems. The activity will help deepen…

  9. The Problem with Theory Is the Problem with Practice.

    ERIC Educational Resources Information Center

    Otte, George

    When composition educators talk about either "theory" or "practice," they are not referring to a monolithic and unified field, but instead to any number of competing, ideologically charged metacommentaries. The "problem with practice" refers to its own socially complex and temporally diffuse nature. Applications of theory to practice often are…

  10. The Problem of Assessing Problem Solving: Can Comparative Judgement Help?

    ERIC Educational Resources Information Center

    Jones, Ian; Inglis, Matthew

    2015-01-01

    School mathematics examination papers are typically dominated by short, structured items that fail to assess sustained reasoning or problem solving. A contributory factor to this situation is the need for student work to be marked reliably by a large number of markers of varied experience and competence. We report a study that tested an…

  11. Organization of Classical Genetics Problems by Faculty Problem Solvers.

    ERIC Educational Resources Information Center

    Smith, Mike U.

    This paper is a progress report of the first phase of a project which essentially seeks to replicate previous studies using the successful/unsuccessful design in an attempt to: (1) corroborate the surface/deep structure conclusion which has become an essential component of an understanding of problem-solving; (2) examine more closely the nature of…

  12. OPEN PROBLEM: Some problems in differential geometry and topology

    NASA Astrophysics Data System (ADS)

    Donaldson, S. K.

    2008-09-01

    This does not attempt to be a systematic overview or to present a comprehensive list of problems. We outline some questions in three different areas which seem interesting to the author. Experts will learn little that is new; our goal is to give some picture of the fields for non-specialists.

  13. Fracture problems in composite materials

    NASA Technical Reports Server (NTRS)

    Erdogan, F.

    1972-01-01

    A series of fracture problems in composite materials are identified, their methods of solution are briefly discussed, and some sample results are presented. The main problem of interest is the determination of the stress state in the neighborhood of localized imperfections such as cracks and inclusions which may exist in the composite. Particular emphasis is placed on the evaluation of quantities such as the stress intensity factors, the power of the stress singularity, and the strain energy release rate, which may be used directly or indirectly in connection with an appropriate fracture criterion for the prediction of fracture initiation and propagation load levels. The topics discussed include a crack in layered composites, a crack terminating at and going through a bi-material interface, a penny-shaped crack in a filament-reinforced elastic matrix, and inclusion problems in bonded materials.

  14. Psychological Distress and Problem Drinking.

    PubMed

    Mentzakis, Emmanouil; Roberts, Bayard; Suhrcke, Marc; McKee, Martin

    2016-03-01

    We examine the influence of harmful alcohol use on mental health using a flexible two-step instrumental variables approach and household survey data from nine countries of the former Soviet Union. Using alcohol advertisements to instrument for alcohol, we show that problem drinking has a large detrimental effect on psychological distress, with problem drinkers exhibiting a 42% increase in the number of mental health problems reported and a 15% higher chance of reporting very poor mental health. Ignoring endogeneity leads to an underestimation of the damaging effect of excessive drinking. Findings suggest that more effective alcohol policies and treatment services in the former Soviet Union may have added benefits in terms of reducing poor mental health. PMID:25640167

  15. Theoretical Problems in Materials Science

    NASA Technical Reports Server (NTRS)

    Langer, J. S.; Glicksman, M. E.

    1985-01-01

    Interactions between theoretical physics and material sciences to identify problems of common interest in which some of the powerful theoretical approaches developed for other branches of physics may be applied to problems in materials science are presented. A unique structure was identified in rapidly quenched Al-14% Mn. The material has long-range directed bonds with icosahedral symmetry which does not form a regular structure but instead forms an amorphous-like quasiperiodic structure. Finite volume fractions of second phase material is advanced and is coupled with nucleation theory to describe the formation and structure of precipitating phases in alloys. Application of the theory of pattern formation to the problem of dendrite formation is studied.

  16. Image Processing: Some Challenging Problems

    NASA Astrophysics Data System (ADS)

    Huang, T. S.; Aizawa, K.

    1993-11-01

    Image processing can be broadly defined as the manipulation of signals which are inherently multidimensional. The most common such signals are photographs and video sequences. The goals of processing or manipulation can be (i) compression for storage or transmission; (ii) enhancement or restoration; (iii) analysis, recognition, and understanding; or (iv) visualization for human observers. The use of image processing techniques has become almost ubiquitous; they find applications in such diverse areas as astronomy, archaeology, medicine, video communication, and electronic games. Nonetheless, many important problems in image processing remain unsolved. It is the goal of this paper to discuss some of these challenging problems. In Section I, we mention a number of outstanding problems. Then, in the remainder of this paper, we concentrate on one of them: very-low-bit-rate video compression. This is chosen because it involves almost all aspects of image processing.

  17. Challenge problems for artificial intelligence

    SciTech Connect

    Selman, B.; Brooks, R.A.; Dean, T.

    1996-12-31

    AI textbooks and papers of ten discuss the big questions, such as {open_quotes}how to reason with uncertainty{close_quotes}, {open_quotes}how to reason efficiently{close_quotes}, or {open_quotes}how to improve performance through learning.{close_quotes} It is more difficult, however, to find descriptions of concrete problems or challenges that are still ambitious and interesting, yet not so open-ended. The goal of this panel is to formulate a set of such challenge problems for the field. Each panelist was asked to formulate one or more challenges. The emphasis is on problems for which there is a good chance that they will be resolved within the next five to ten years.

  18. Food production -- problems and prospects.

    PubMed

    Anifowoshe, T O

    1990-03-01

    Improvements are needed in balancing the problems associated with population growth and food production. A review of the problems of rapid population growth and declining food production and suggestions for resolution are given. World population has increased over the past 10 years by 760 million, which is equal to adding the combined population of Africa and South America. Future increases are expected to bring total population to 6.1 billion by the year 2000 and 8.2 billion in 2025 (exponential increases). Food production/capita has declined since 1971 in the world and in Nigeria, particularly in the recent past. The food production problem is technical, environmental, social, political, and economic. Various scientific and technological methods for increasing food production are identified: mechanization, irrigation, use of fertilizers, control of weeds and insects, new varieties of farm animals or high-yielding strains of grain, land reclamation, soil conservation, river basin development, adequate storage facilities, infrastructure development, and birth control. Economic and social approaches involve short-term and long-term strategies in social readjustment and institutional change. For instance, large scale farmers should become contract growers for certain firms. Bureaucratic red tape should be eliminated in institutions which provide agricultural services. Environmental problems need urgent attention. Some of these problems are soil erosion from mechanization, water salinization from irrigation, accumulation of DDT in food and water and animal life from pesticide use, and water pollution from chemical fertilizers. Food production can be increased with more ecologically sound practices. Information about weather and weather forecasting allows for more suitable land management. The influence of rainfall (the amount and distribution) in Nigeria is greater than any other climatic factor. Solar radiation is a significant feature in production of dry matter and

  19. Efficient algorithms for proximity problems

    SciTech Connect

    Wee, Y.C.

    1989-01-01

    Computational geometry is currently a very active area of research in computer science because of its applications to VLSI design, database retrieval, robotics, pattern recognition, etc. The author studies a number of proximity problems which are fundamental in computational geometry. Optimal or improved sequential and parallel algorithms for these problems are presented. Along the way, some relations among the proximity problems are also established. Chapter 2 presents an O(N log{sup 2} N) time divide-and-conquer algorithm for solving the all pairs geographic nearest neighbors problem (GNN) for a set of N sites in the plane under any L{sub p} metric. Chapter 3 presents an O(N log N) divide-and-conquer algorithm for computing the angle restricted Voronoi diagram for a set of N sites in the plane. Chapter 4 introduces a new data structure for the dynamic version of GNN. Chapter 5 defines a new formalism called the quasi-valid range aggregation. This formalism leads to a new and simple method for reducing non-range query-like problems to range queries and often to orthogonal range queries, with immediate applications to the attracted neighbor and the planar all-pairs nearest neighbors problem. Chapter 6 introduces a new approach for the construction of the Voronoi diagram. Using this approach, we design an O(log N) time O (N) processor algorithm for constructing the Voronoi diagram with L{sub 1} and L. metrics on a CREW PRAM machine. Even though the GNN and the Delaunay triangulation (DT) do not have an inclusion relation, we show, using some range type queries, how to efficiently construct DT from the GNN relations over a constant number of angular ranges.

  20. The Averaging Problem in Cosmology

    NASA Astrophysics Data System (ADS)

    Paranjape, Aseem

    2009-06-01

    This thesis deals with the averaging problem in cosmology, which has gained considerable interest in recent years, and is concerned with correction terms (after averaging inhomogeneities) that appear in the Einstein equations when working on the large scales appropriate for cosmology. It has been claimed in the literature that these terms may account for the phenomenon of dark energy which causes the late time universe to accelerate. We investigate the nature of these terms by using averaging schemes available in the literature and further developed to be applicable to the problem at hand. We show that the effect of these terms when calculated carefully, remains negligible and cannot explain the late time acceleration.

  1. Rosetta Stones for Energy Problems.

    ERIC Educational Resources Information Center

    Hayden, Howard C.

    1981-01-01

    Demonstrates, using specific problems, how various energy units can be converted to joules and power units to watts. Conversion tables are provided for power, energy, generation values, thermal insulation, consumption values, sunlight, with tables also on metric prefixes and time conversions. (SK)

  2. Inverse problem in radionuclide transport

    SciTech Connect

    Yu, C.

    1988-01-01

    The disposal of radioactive waste must comply with the performance objectives set forth in 10 CFR 61 for low-level waste (LLW) and 10 CFR 60 for high-level waste (HLW). To determine probable compliance, the proposed disposal system can be modeled to predict its performance. One of the difficulties encountered in such a study is modeling the migration of radionuclides through a complex geologic medium for the long term. Although many radionuclide transport models exist in the literature, the accuracy of the model prediction is highly dependent on the model parameters used. The problem of using known parameters in a radionuclide transport model to predict radionuclide concentrations is a direct problem (DP); whereas the reverse of DP, i.e., the parameter identification problem of determining model parameters from known radionuclide concentrations, is called the inverse problem (IP). In this study, a procedure to solve IP is tested, using the regression technique. Several nonlinear regression programs are examined, and the best one is recommended. 13 refs., 1 tab.

  3. RESULTATIVE VERBS AND OTHER PROBLEMS.

    ERIC Educational Resources Information Center

    HASHIMOTO, ANNE YUE

    THE SO-CALLED RESULTATIVE VERBS IN MANDARIN CHINESE ARE STUDIED WITHIN THE GENERAL FRAMEWORK OF A TRANSFORMATIONAL GRAMMAR. THE RESULTATIVE VERBS ARE GENERALLY CONSIDERED AS CONSISTING OF TWO COMPONENTS--A VERBAL COMPONENT FOLLOWED BY A RESULTATIVE OR DIRECTIONAL COMPLEMENT. OTHER PROBLEMS RELATED TO COMPLEMENTS ARE ALSO TOUCHED UPON, FOR EXAMPLE,…

  4. Serials Problems in Education Libraries.

    ERIC Educational Resources Information Center

    Morrill, Richard L.

    1981-01-01

    Discusses the problem of rising costs for serial subscriptions and declining purchasing power of education libraries, and describes three studies undertaken in a university library to obtain reliable data for recommending the continuation or cancellation of education periodical subscriptions. Eleven references are listed. (CHC)

  5. Solving the wrong hierarchy problem

    NASA Astrophysics Data System (ADS)

    Blinov, Nikita; Hook, Anson

    2016-06-01

    Many theories require augmenting the Standard Model with additional scalar fields with large order one couplings. We present a new solution to the hierarchy problem for these scalar fields. We explore parity- and Z_2 -symmetric theories where the Standard Model Higgs potential has two vacua. The parity or Z_2 copy of the Higgs lives in the minimum far from the origin while our Higgs occupies the minimum near the origin of the potential. This approach results in a theory with multiple light scalar fields but with only a single hierarchy problem, since the bare mass is tied to the Higgs mass by a discrete symmetry. The new scalar does not have a new hierarchy problem associated with it because its expectation value and mass are generated by dimensional transmutation of the scalar quartic coupling. The location of the second Higgs minimum is not a free parameter, but is rather a function of the matter content of the theory. As a result, these theories are extremely predictive. We develop this idea in the context of a solution to the strong CP problem. We show this mechanism postdicts the top Yukawa to be within 1 σ of the currently measured value and predicts scalar color octets with masses in the range 9-200 TeV.

  6. Solving a Spacecraft Design Problem

    NASA Technical Reports Server (NTRS)

    Fisher, D. K.

    1998-01-01

    We have probably all been amazed at the ingenuity of spacecraft engineers when we see some of the solutions they invent for such problems as landing a roving vehicle on Mars-as engineers at the Jet Propulsion Laboratory did for NASA's Mars Pathfinder project-without using retro-rockets or even putting a spacecraft in orbit first.

  7. Investigating the Antibiotic Resistance Problem.

    ERIC Educational Resources Information Center

    Lawson, Michael; Lawson, Amy L.

    1998-01-01

    Seeks to give teachers useful information on the extent of the problem of antibiotic-resistant bacteria, mechanisms bacteria use to resist antibiotics, the causes of the emergence of antibiotic-resistant organisms, and practices that can prevent or reverse this trend. Contains 19 references. (DDR)

  8. The Child-Fat Problem.

    ERIC Educational Resources Information Center

    Eberstadt, Mary

    2003-01-01

    Experts believe that child obesity is a serious medical problem that affects people in all socioeconomic groups. Suggests that there is a relationship between absentee parents, particularly mothers, and obese children, focusing on working/absentee mothers, television watching habits, the prophylactic effect of breastfeeding, and poor exercise…

  9. Robot, computer problem solving system

    NASA Technical Reports Server (NTRS)

    Becker, J. D.; Merriam, E. W.

    1973-01-01

    The TENEX computer system, the ARPA network, and computer language design technology was applied to support the complex system programs. By combining the pragmatic and theoretical aspects of robot development, an approach is created which is grounded in realism, but which also has at its disposal the power that comes from looking at complex problems from an abstract analytical point of view.

  10. Robot computer problem solving system

    NASA Technical Reports Server (NTRS)

    Becker, J. D.; Merriam, E. W.

    1974-01-01

    The conceptual, experimental, and practical aspects of the development of a robot computer problem solving system were investigated. The distinctive characteristics were formulated of the approach taken in relation to various studies of cognition and robotics. Vehicle and eye control systems were structured, and the information to be generated by the visual system is defined.

  11. The Particle--Motion Problem.

    ERIC Educational Resources Information Center

    Demana, Franklin; Waits, Bert K.

    1993-01-01

    Discusses solutions to real-world linear particle-motion problems using graphing calculators to simulate the motion and traditional analytic methods of calculus. Applications include (1) changing circular or curvilinear motion into linear motion and (2) linear particle accelerators in physics. (MDH)

  12. Problem Solvers' Conceptions about Osmosis.

    ERIC Educational Resources Information Center

    Zuckerman, June T.

    1994-01-01

    Discusses the scheme and findings of a study designed to identify the conceptual knowledge used by high school students to solve a significant problem related to osmosis. Useful tips are provided to teachers to aid students in developing constructs that maximize understanding. (ZWH)

  13. Problems, Perseverance, and Mathematical Residue.

    ERIC Educational Resources Information Center

    Thom, Jennifer S.; Pirie, Susan E. B.

    2002-01-01

    Reports on a study in which three 3rd grade students were presented with the volume of cuboids. Examines the problem solving actions students demonstrate and analyzes students' strategies and solutions. Explores the connection between spatial structuring and the use of numerical operation. Considers perseverance and control emerging when solving…

  14. Solving Problems by Reading Mathematics.

    ERIC Educational Resources Information Center

    Witkowski, Joseph C.

    1988-01-01

    A course at the University of Georgia is described that helps students acquire problem-solving skills so that ultimately the entire remedial program would be improved, giving students with major deficiencies in basic skills a better chance to succeed in their regular university courses. (MLW)

  15. Problems with German Science Education.

    ERIC Educational Resources Information Center

    Riess, Falk

    2000-01-01

    The main problems of science teaching in Germany are students' lack of interest and motivation and their poor understanding of scientific concepts, ideas, methods, and results. Lists examples from science curricula and textbooks and describes some reform projects in Germany. Proposes a compensatory program in order to create prerequisites for…

  16. Group Counselling for Problem Gambling.

    ERIC Educational Resources Information Center

    Coman, Gregory J.; Evans, Barry J.; Burrows, Graham D.

    2002-01-01

    Group counseling has been used to assist individuals to overcome difficulties associated with problem gambling behavior; however, there are few reports of this application in the clinical and research literature. This paper provides a brief review of group counseling, and describes the application of group counseling to assist individuals with…

  17. Environmental Problems and the Scientist

    ERIC Educational Resources Information Center

    Batisse, Michel

    1973-01-01

    Suggests that any environmental problem can be traced at biosphere, technosphere, sociosphere, and noosphere level. Scientists have generally ignored the latter two spheres in making scientific discoveries. New social ethics need to be recognized that are based on progress, and scientists must consider how these ethics are influenced by their…

  18. Research Grants: Problems and Options.

    ERIC Educational Resources Information Center

    Martin, Brian

    2000-01-01

    Provides a broader perspective on research grants. Outlines several key types of problems with grant schemes (bias, waste, discouragement, orientation to interests) and presents several methods for decision making (administrative decision, peer review, performance-based funding, equality, community-based allocation). Assesses recent changes in…

  19. Eldercare at Home: Communication Problems

    MedlinePlus

    ... t remember the word, the name of the game." You might ask how to play the game, where it is played, or offer a few ... Plan Isn't Working If communication problems are serious and persist, review the section on "When to ...

  20. "Top School Problems" Are Myths.

    ERIC Educational Resources Information Center

    Males, Mike

    1992-01-01

    A well-known "study" comparing the top school problems of 1940 (talking and gum chewing) with those of 1987 (drug abuse, pregnancy, and violence) is nonexistent. In 1940, 49 percent of all youth did not finish high school, 37,000 teenagers died from violence or disease, and 335,000 teens gave birth. Educators should discount pastoral memories and…

  1. Childhood Obesity: A Heavy Problem

    ERIC Educational Resources Information Center

    Costley, Kevin C.; Leggett, Timothy

    2010-01-01

    The youth of today are faced with a big problem; they are becoming more obese every day. The time of children playing outside all day and being extremely active has been overtaken by the television and video games. The days of sitting down as a family and eating a good healthy meal has been replaced by the rush to the nearest fast food…

  2. Building Collections. The Problem Novel

    ERIC Educational Resources Information Center

    Krapp, JoAnn Vergona

    2005-01-01

    Realistic fiction has changed dramatically over the years. Formerly a sentimental, family-oriented story, today's realism focuses on today's problems and the protagonist's struggle to overcome them. Parents, once portrayed as protectors of the children, now often are cast as failures, needing help themselves. Yesterday's taboo subjects--drugs,…

  3. Literacy as a Human Problem.

    ERIC Educational Resources Information Center

    Raymond, James C., Ed.

    First presented as papers in a symposium on literacy conducted at the University of Alabama, essays in this volume explore three areas of human literacy--law, linguistics, and the English language; testing; and literacy's relation with culture and human consciousness. Following an introduction examining literacy as a human problem, the following…

  4. Breathing Problems: An Individualized Program.

    ERIC Educational Resources Information Center

    Vodola, Thomas M.

    As one of the components of the Project ACTIVE (All Children Totally Involved Exercising) Teacher Training Model Kit, the manual is designed to enable the educator to organize, conduct, and evaluate individualized-personalized physical education programs for children (prekindergarten through high school) with breathing problems. An introductory…

  5. Introduction: Unsolved Problems on Noise

    NASA Astrophysics Data System (ADS)

    Oriols, X.; Ciliberto, S.

    2016-05-01

    This paper is an introduction to the special issue of the 7th Int. Conf. on Unsolved Problems on Noise (UPoN) that took place at Casa Convalescència in Barcelona (Spain) in July 2015. The aim of the UPoN conferences is to provide a forum for researchers working on different fields of noise, fluctuations and variability, where they present their scientific problems which resist solutions. The papers of this Special Issue reflect the interdisciplinary topics (physics, biology, circuits, financial markets, psychology, technology, etc) presented at the UPoN conference. Noise is not only a hindrance to signal detection, but it is indeed a valuable source of information (not present in the signal) that help us to get a deeper understanding on how Nature works. This special issue of the 7th International Conference on Unsolved Problems on Noise (UPoN) is dedicated to Laszlo Kish in the occasion of his 60th birthday. He organized the first edition of these UPoN conferences in Szeged (Hungary) in 1996. Many of us have greatly benefited from his ‘volcanic imagination in tackling new problems from unconventional points of views’.

  6. Robot computer problem solving system

    NASA Technical Reports Server (NTRS)

    Becker, J. D.; Merriam, E. W.

    1974-01-01

    The conceptual, experimental, and practical phases of developing a robot computer problem solving system are outlined. Robot intelligence, conversion of the programming language SAIL to run under the THNEX monitor, and the use of the network to run several cooperating jobs at different sites are discussed.

  7. Behavior: My Problem or Yours?

    ERIC Educational Resources Information Center

    Trede, Mildred

    1991-01-01

    Activities are described for learning about problem classroom behaviors, the impact of one's manner of attire on one's behavior, and personal responsibility for one's behavior. Learning activities include role playing, making math puzzles, writing personal anecdotes, drawing a persuasive cartoon concerning smoking and discipline, and making bar…

  8. Dyslexia: Problems of Reading Disabilities.

    ERIC Educational Resources Information Center

    Goldberg, Herman K.; Schiffman, Gilbert B.

    The purpose of this book is to provide an understanding of both the educational and medical aspects of reading and to show how they are interrelated in reading disabilities. The various aspects of reading disabilities are presented in the following chapters: Introduction to the Reading Problem; Early Predictive Studies; Psychological Evaluation;…

  9. Skin problems in sugar artists.

    PubMed

    Bangha, E; Elsner, P

    1996-11-01

    Sugar artistry is a growing profession amongst bakers and confectioners and an increasingly common hobby in amateur cooks. The main work consists of manual manipulation of sugar which is formed into figures and objects for table and food decoration. The sugar must be warmed up to 50 degrees C in order to be liquid and malleable and so the artists suffer from diverse thermally induced skin problems on their hands. Such changes have not to date been reported in the dermatological literature. In this study we report our experience in 50 Swiss sugar artists who have suffered from skin problems. The study took the form of a questionnaire survey. The response rate was 30 out of 50. Twenty-six reported no chronic skin disorder. Four suffered from a palmar vesicular relapsing type of chronic eczema. The main skin problems on the hands during work with hot sugar were increased sweating, seen in 20 out of 30 (67%), and burning with erythema and blistering, seen in 12 out of 30 (40%). Most participants (83%) were highly irritated by the skin problems during their work, and applied a protective cream before working with sugar, or wore rubber gloves. Topical therapy with a preparation containing 10% aluminium chloride hexahydrate, used once daily for 3 weeks, evaluated in 14 participants, decreased sweating in 10 (71%) and reduced the thermally induced erythema in one (7%). PMID:8977679

  10. Psychological Problems in Mental Deficiency.

    ERIC Educational Resources Information Center

    Sarason, Seymour B.; Doris, John

    A statement of goals and the rationale for organization precede a historical discussion of mental deficiency and society. The problem of labels like IQ and brain injured and the consequences of the diagnostic process are illustrated by case histories; case studies are also used to examine the criteria used to decide who is retarded and to discuss…

  11. Solving the wrong hierarchy problem

    DOE PAGESBeta

    Blinov, Nikita; Hook, Anson

    2016-06-29

    Many theories require augmenting the Standard Model with additional scalar fields with large order one couplings. We present a new solution to the hierarchy problem for these scalar fields. We explore parity- and Z2-symmetric theories where the Standard Model Higgs potential has two vacua. The parity or Z2 copy of the Higgs lives in the minimum far from the origin while our Higgs occupies the minimum near the origin of the potential. This approach results in a theory with multiple light scalar fields but with only a single hierarchy problem, since the bare mass is tied to the Higgs massmore » by a discrete symmetry. The new scalar does not have a new hierarchy problem associated with it because its expectation value and mass are generated by dimensional transmutation of the scalar quartic coupling. The location of the second Higgs minimum is not a free parameter, but is rather a function of the matter content of the theory. As a result, these theories are extremely predictive. We develop this idea in the context of a solution to the strong CP problem. Lastly, we show this mechanism postdicts the top Yukawa to be within 1σ of the currently measured value and predicts scalar color octets with masses in the range 9-200 TeV.« less

  12. Selected Problems in Sports Safety.

    ERIC Educational Resources Information Center

    American Alliance for Health, Physical Education, and Recreation, Washington, DC.

    This publication, covering a broad spectrum of sports safety problems, is designed as a source of information for those who plan, organize, administer, or evaluate various physical education and recreational activities, athletics, or sports. In the first section, the prevention of sports injury is stressed with attention to different age groups…

  13. Uncommon Infant and Newborn Problems

    MedlinePlus

    It can be scary when your baby is sick, especially when it is not an everyday problem like a cold or a fever. You may not know whether the ... treat it. If you have concerns about your baby's health, call your health care provider right away. ...

  14. Linearization problem in pseudolite surveys

    NASA Astrophysics Data System (ADS)

    Cellmer, Slawomir; Rapinski, Jacek

    2010-06-01

    GPS augmented with pseudolites (PL), can be used in various engineering surveys. Also pseudolite—only navigation system can be designed and used in any place, even if GPS signal is not available (Kee et al. Development of indoor navigation system using asynchronous pseudolites, 1038-1045, 2000). Especially in engineering surveys, where harsh survey environment is common, pseudolites have a lot of applications. Pseudolites may be used in construction sites, open pit mines, city canyons, GPS and PL baseline processing is similar, although there are few differences that must be taken into account. One of the major issues is linearization problem. The source of the problem is neglecting second terms of Taylor series expansion in GPS baseline processing software. This problem occurs when the pseudolite is relatively close to the receiver, which is the case in PL surveys. In this paper authors presents the algorithm for GPS + PL data processing including, neglected in classical GPS only approach, second terms of Taylor series expansion. The mathematical model of adjustment problem, detailed proposal of application in baseline processing algorithms, and numerical tests are presented.

  15. Time Out for Problem Solving.

    ERIC Educational Resources Information Center

    Champagne, Audrey B.; And Others

    Teachers in elementary schools, supervisors of instruction, and other educational practitioners are the primary audience for this publication. The paper presents philosophical, psychological, and practical reasons for including a problem-solving approach in elementary school instruction. It draws on the writings of John Dewey, Jean Piaget, James…

  16. Eldercare at Home: Hearing Problems

    MedlinePlus

    ... members and friends to comment on how much communication has improved when your mother is wearing the hearing aid. If your mother is concerned about the appearance of a hearing aid, tell her that most women can style their hair to cover the hearing aids. Problem " ...

  17. English as a Problem Language

    ERIC Educational Resources Information Center

    Moss, Peter

    2010-01-01

    At a time when English has emerged as the dominant language of academic communication, there is a disturbing silence about the risks and problems attendant on this development and a failure to ask critical questions about its consequences. Who gains and who loses? What is lost in translation? What are the consequences of one way linguistic…

  18. PROBLEMS IN MODERN GREEK LEXICOGRAPHY.

    ERIC Educational Resources Information Center

    KAHANE, HENRY; KAHANE, RENEE

    PROBLEMS DEALING WITH LEVELS OF SPEECH AND LEVELS OF ANALYSIS IN CONNECTION WITH MODERN GREEK LEXICOGRAPHICAL STUDY WERE DISCUSSED. CONCERNING THE POSSIBLE CONSTRUCTION OF A COMPETENT BILINGUAL DICTIONARY, THE INVESTIGATORS SUGGESTED THAT THE VARIOUS STRUCTURES (NAMELY, PHONOLOGY, MORPHOLOGY, AND SYNTAX) BE TIED TOGETHER TO INVOLVE (1) LISTING IN…

  19. Urban Problems and Community Development.

    ERIC Educational Resources Information Center

    Ferguson, Ronald F., Ed.; Dickens, William T., Ed.

    The essays in this collection promote a conception of community development that entails building practical capacities to improve the quality of life among residents of targeted neighborhoods. The causes, consequences, and potential solutions of urban problems that lie both inside and outside neighborhood borders are emphasized. The chapters are:…

  20. Problems in unification and supergravity

    SciTech Connect

    Farrar, G.; Henyey, F.

    1984-01-01

    Problems in unification of the various gauge groups, quantum gravity, supersymmetry and supergravity, compact dimensions of space-time, and conditions at the beginning of the universe are discussed. Separate entries were prepared for the data base for the 15 papers presented. (WHK)

  1. Customer Service & Team Problem Solving.

    ERIC Educational Resources Information Center

    Martin, Sabrina Budasi

    This curriculum guide provides materials for a six-session, site-specific training course in customer service and team problem solving for the Claretian Medical Center. The course outline is followed the six lesson plans. Components of each lesson plan include a list of objectives, an outline of activities and discussion topics for the lesson,…

  2. Malaysian Serials: Issues and Problems.

    ERIC Educational Resources Information Center

    Bahri, Che Norma

    This paper analyzes the issues and problems while looking at the trends and developments of serials publishing in Malaysia. The first section provides background; topics addressed include the country and people of Malaysia, the history of serials publishing in Malaysia, categories and formats of serials publishing, academic publications,…

  3. Problem Based Learning in Metaverse

    ERIC Educational Resources Information Center

    Barry, Dana M.; Kanematsu, Hideyuki; Fukumura, Yoshimi

    2010-01-01

    Problem Based Learning (PBL) is a powerful tool for both science and engineering education in the real world. Therefore, Japanese educators/researchers (with assistance from a US educator) carried out a pilot study to determine the effectiveness of using PBL activities in Metaverse. Their project was carried out by student teams from the US and…

  4. Polyomino Problems to Confuse Computers

    ERIC Educational Resources Information Center

    Coffin, Stewart

    2009-01-01

    Computers are very good at solving certain types combinatorial problems, such as fitting sets of polyomino pieces into square or rectangular trays of a given size. However, most puzzle-solving programs now in use assume orthogonal arrangements. When one departs from the usual square grid layout, complications arise. The author--using a computer,…

  5. The Problem of Bicultural Learning

    ERIC Educational Resources Information Center

    Conkright, Tom D.

    1975-01-01

    Discusses concerns about the conceptualization of the problems and potential benefits related to the bicultural learning situation. Presents ideas for helping to build a conceptual framework to tackle the questions posed. [Available from CAE, 1703 New Hampshire Avenue, N.W., Washington, D.C. 20009]. (Author/AM)

  6. The Problem of World Hunger.

    ERIC Educational Resources Information Center

    Czarra, Fred R.; Long, Cathryn J., Eds.

    1983-01-01

    The major hunger problem today is chronic undernutrition, the primary cause of which is poverty. Hunger can be alleviated through food supplements, nutrition programs, and disaster relief. It can be eliminated by redistributing existing wealth and producing enough food and through equitable economic growth and a world food security system. (CS)

  7. Sour landfill gas problem solved

    SciTech Connect

    Nagl, G.; Cantrall, R.

    1996-05-01

    In Broward County, Fla., near Pompano Beach, Waste Management of North America (WMNA, a subsidiary of WMX Technologies, Oak Brook, IL) operates the Central Sanitary Landfill and Recycling Center, which includes the country`s largest landfill gas-to-energy plant. The landfill consists of three collection sites: one site is closed, one is currently receiving garbage, and one will open in the future. Approximately 9 million standard cubic feet (scf) per day of landfill gas is collected from approximately 300 wells spread over the 250-acre landfill. With a dramatic increase of sulfur-containing waste coming to a South Florida landfill following Hurricane Andrew, odors related to hydrogen sulfide became a serious problem. However, in a matter of weeks, an innovative desulfurization unit helped calm the landfill operator`s fears. These very high H{sub 2}S concentrations caused severe odor problems in the surrounding residential area, corrosion problems in the compressors, and sulfur dioxide (SO{sub 2}) emission problems in the exhaust gas from the turbine generators.

  8. Energy Problems Provide Job Opportunities.

    ERIC Educational Resources Information Center

    Moore, Allen B.

    In response to the problems created by a diminishing energy supply but an increasing energy demand, this second in a series of national reports studies the linkage of vocational education and energy. Through an examination of selected literature with reference to types of energy resources, the author identifies the emerging occupations related to…

  9. Language Problems of Developing Nations.

    ERIC Educational Resources Information Center

    Fishman, Joshua A., Ed.; And Others

    Most of the papers in this collection were presented at a conference on language problems of the developing nations at Airlie House, Warrenton, Virginia in November 1966. This conference was one of the several organized and sponsored by the Committee on Sociolinguistics of the Social Science Research Council in its effort to promote…

  10. The Problem with Toxic Wastes.

    ERIC Educational Resources Information Center

    Beecher, John L.; Fossa, Arthur J.

    1980-01-01

    Traced is the historical development of toxic waste problems in western New York State from 1825 to the present. Three major data sources are described: Industrial Chemical Survey, Inventory of Industrial Waste Generation Study, and the Interagency Task Force Study, developed by the Department of Environmental Conservation to prevent future…

  11. Modeling Applied to Problem Solving

    NASA Astrophysics Data System (ADS)

    Pawl, Andrew; Barrantes, Analia; Pritchard, David E.

    2009-11-01

    We describe a modeling approach to help students learn expert problem solving. Models are used to present and hierarchically organize the syllabus content and apply it to problem solving, but students do not develop and validate their own Models through guided discovery. Instead, students classify problems under the appropriate instructor-generated Model by selecting a system to consider and describing the interactions that are relevant to that system. We believe that this explicit System, Interactions and Model (S.I.M.) problem modeling strategy represents a key simplification and clarification of the widely disseminated modeling approach originated by Hestenes and collaborators. Our narrower focus allows modeling physics to be integrated into (as opposed to replacing) a typical introductory college mechanics course, while preserving the emphasis on understanding systems and interactions that is the essence of modeling. We have employed the approach in a three-week review course for MIT freshmen who received a D in the fall mechanics course with very encouraging results.

  12. Sexual Harrassment: A Hidden Problem.

    ERIC Educational Resources Information Center

    Sandler, Bernice R.; And Others

    1981-01-01

    The hidden but serious problem of sexual harassment of students and employees by college faculty is discussed, some statistics are given, and legal and court opinions outlined. Harassment as a violation of Title IX is analyzed, and implications for institutional action to curb it are outlined. (MSE)

  13. Problem Gambling on College Campuses

    ERIC Educational Resources Information Center

    McComb, Jennifer L.; Hanson, William E.

    2009-01-01

    The vast majority of college students gamble, with some doing so problematically. This article discusses gambling and problem gambling among college students, framing it as an emerging health issue on college campuses nationwide. Given that 4 out of 5 college students admit to gambling, and that approximately 8% gamble problematically, it is…

  14. Problems on Divisibility of Binomial Coefficients

    ERIC Educational Resources Information Center

    Osler, Thomas J.; Smoak, James

    2004-01-01

    Twelve unusual problems involving divisibility of the binomial coefficients are represented in this article. The problems are listed in "The Problems" section. All twelve problems have short solutions which are listed in "The Solutions" section. These problems could be assigned to students in any course in which the binomial theorem and Pascal's…

  15. Theoretical and Philosophical Perspectives to Problem Solving.

    ERIC Educational Resources Information Center

    Sherman, Thomas M.; And Others

    1988-01-01

    Five articles explore various theoretical aspects of problems and problem solving skills. Highlights include strategies to learn problem solving skills; knowledge structures; metacognition; behavioral processes and cognitive psychology; erotetic logic; creativity as an aspect of computer problem solving; and programing as a problem-solving…

  16. Word Problems: Where Test Bias Creeps In.

    ERIC Educational Resources Information Center

    Chipman, Susan F.

    The problem of sex bias in mathematics word problems is discussed, with references to the appropriate literature. Word problems are assessed via cognitive science analysis of word problem solving. It has been suggested that five basic semantic relations are adequate to classify nearly all story problems, namely, change, combine, compare, vary, and…

  17. Predicting the Problem Behavior in Adolescents

    ERIC Educational Resources Information Center

    Karaman, Neslihan G.

    2013-01-01

    Problem statement: Problem behavior theory describes both protective factors and risk factors to explain adolescent problem behaviors, such as delinquency, alcohol use, and reckless driving. The theory holds that problem behaviors involving risky behavior are used by adolescents as a means to gain peer acceptance and respect. Problem behaviors…

  18. Children's Health Problems and Maternal Work Status.

    ERIC Educational Resources Information Center

    Salkever, David S.

    1982-01-01

    This paper estimates the influence on working mothers' employment status of children's health problems. Effects are estimated for several different types of families, various groups of health problems, and differing degrees of problem severity. (CT)

  19. Problems of Adolescents in Sydney, Australia

    ERIC Educational Resources Information Center

    Collins, John K.; Harper, Juliet F.

    1974-01-01

    Investigated the problems of 514 male and female adolescents of 14 and 15 years of age using an open-ended questionnaire. Boys reported more problems concerned with educational adjustments, girls more problems concerned with family adjustment. (Author/SDH)

  20. Ethical problems in psychopharmacological research.

    PubMed

    Gentili, C; Ferrari, G

    1979-01-01

    1. Scientific research poses considerable ethical problems which in human psychopharmacological studies are frequently faced by singling out consent as the only reliable source of human respect, although it is never free, spontaneous, or informed. 2. On the other hand, various ethical problems present in the "life" of a new substance in the case of industry and preclinical, clinical and mass experiments, are left behind. 3. Thus there arise justified protests which go so far as disowning science and technology. To criticize science and technology is of no use: incorrect use of them must be prevented. 4. Such a guarantee can only come from an international control committee, capable of coping with a multinational power such as industry, supported by peripheral elective committees, which grant the citizens a direct participation in the administration of health. PMID:400986

  1. Occupational Health Problems of Musicians

    PubMed Central

    Chong, John; Lynden, Melody; Harvey, David; Peebles, Marie

    1989-01-01

    Musicians, as well as other performing artists, may have their careers interrupted by, interfered with, or terminated by occupational health problems involving the neuro-musculoskeletal system. Adverse working conditions, organization, and activity may affect the health of musicians in all age groups and at all levels of performing ability. Instrument-specific health problems are related to excessive force, static loading, repetitive movement, and duration of musical performance. Important risk factors are 1) change in technique or instrument; 2) intense preparation for a performance; 3) preparation of a new and difficult repertoire; and 4) prolonged periods of performance without rest. Treatment protocols and health promotion or disease prevention programs are being developed in collaboration with the performing arts community. ImagesFigure 1Figure 2Figure 3 PMID:21248930

  2. Coagulation problems in human pregnancy.

    PubMed Central

    Redman, C. W.

    1979-01-01

    Coagulation problems in pregnancy are primarily associated with overactivity of the intrinsic clotting system. This accounts for the increased incidence of thrombo-embolism during pregnancy. Where specific obstetric complications cause clotting problems the common underlying feature is usually placental pathology as in abruptio placentae, pre-eclampsia or hydatidiform mole. Abnormal activation of the clotting system is an early, and occasionally the first detectable feature of pre-eclampsia, but there is no evidence that this is a primary change. Therefore the role of anticoagulant treatment in the management of pre-eclampsia remains questionable. A new test for estimating factor VIII consumption is proving to be a sensitive index of early activation of the clotting system and can be used for the diagnosis of early pre-eclampsia. PMID:382170

  3. Retrofitting and the mu Problem

    SciTech Connect

    Green, Daniel; Weigand, Timo; /SLAC /Stanford U., Phys. Dept.

    2010-08-26

    One of the challenges of supersymmetry (SUSY) breaking and mediation is generating a {mu} term consistent with the requirements of electro-weak symmetry breaking. The most common approach to the problem is to generate the {mu} term through a SUSY breaking F-term. Often these models produce unacceptably large B{mu} terms as a result. We will present an alternate approach, where the {mu} term is generated directly by non-perturtative effects. The same non-perturbative effect will also retrofit the model of SUSY breaking in such a way that {mu} is at the same scale as masses of the Standard Model superpartners. Because the {mu} term is not directly generated by SUSY breaking effects, there is no associated B{mu} problem. These results are demonstrated in a toy model where a stringy instanton generates {mu}.

  4. Vortex shedding and Maxwell's problem

    NASA Astrophysics Data System (ADS)

    Michelin, Sebastien; Smith, Stefan Llewellyn

    2006-11-01

    The coupled problem of a flow around a solid body has applications from the fall of objects in a fluid to the computation of forces on wind-exposed structures. A simplified 2D model is proposed here for the interaction between solid bodies and potential flows. Potential flows over sharp edges generate singular velocities at the edges. To satisfy the Kutta condition, vorticity sheets must be shed from the edges to remove these singularities. Here 2D vorticity sheets are represented as discrete point-vortices with monotically varying intensity. From the fluid momentum conservation, an equation of motion for these vortices, the Brown and Michael equation, is derived and mechanical efforts applied by the fluid on the body are computed. The set of dynamical equations obtained for the fluid-body system is closed and is applied to Maxwell's problem of the 2D fall of a plate in an inviscid fluid initially at rest.

  5. Some nutritional problems of horses.

    PubMed

    Hintz, H F; Kallfelz, F A

    1981-07-01

    The effects of overfeeding, calcium-phosphorus imbalance, misuse of supplements and false advertising on equine nutrition are discussed. Overfeeding is known to cause disorders in several species but, although a similar relationship has been suggested on clinical evidence, no controlled trials on horses have been reported. It has also been suggested that overfeeding is a problem only for those horses with a genetic predisposition to skeletal problems. The importance of adequate calcium and phosphorus levels has been known for many years but severe cases of calcium deficiency still occur. Client education is important and should not be neglected. Excessive use of supplements containing high levels of trace minerals (eg, iodine and selenium) or fat soluble vitamins (eg, vitamin A and vitamin D) can be harmful. Some manufacturers advertise supplements in terms which may inadvertently or intentionally misrepresent their products. Supplements should, therefore, be selected carefully to ensure that they meet the particular requirements of the individual. PMID:7197619

  6. Problems in characterizing barrier performance

    NASA Technical Reports Server (NTRS)

    Jordan, Harry F.

    1988-01-01

    The barrier is a synchronization construct which is useful in separating a parallel program into parallel sections which are executed in sequence. The completion of a barrier requires cooperation among all executing processes. This requirement not only introduces the wait for the slowest process delay which is inherent in the definition of the synchronization, but also has implications for the efficient implementation and measurement of barrier performance in different systems. Types of barrier implementation and their relationship to different multiprocessor environments are described. Then the problem of measuring the performance of barrier implementations on specific machine architecture is discussed. The fact that the barrier synchronization requires the cooperation of all processes makes the problem of performance measurement similarly global. Making non-intrusive measurements of sufficient accuracy can be tricky on systems offering only rudimentary measurement tools.

  7. Reading problems and depressed mood.

    PubMed

    Maughan, Barbara; Rowe, Richard; Loeber, Rolf; Stouthamer-Loeber, Magda

    2003-04-01

    Although reading difficulties show well-established overlaps with disruptive behavior disorders in childhood, much less is known about reading-disabled children's vulnerability to emotional difficulties. Using longitudinal data from 6 assessments of boys in the Pittsburgh Youth Study, we found robust links between severe, persistent reading problems and increased risk for depressed mood in a community sample of boys aged 7 and 10 years at initial assessment, though not in those who had already entered their teens. These associations could not be accounted for in terms of selected family risks or comorbid disruptive behaviors; instead, the pattern of the findings pointed to the existence of more direct causal processes whereby reading problems influence younger boys' risk of depressed mood. PMID:12735404

  8. An archetype hydrogen atmosphere problem

    NASA Technical Reports Server (NTRS)

    Athay, R. G.; Mihalas, D.; Shine, R. A.

    1975-01-01

    Populations for the first three bound states and the continuum of hydrogen are determined for an isothermal hydrostatic atmosphere at 20,000 K. The atmosphere is treated as optically thin in the Balmer and Paschen continua and illuminated by continuum radiation at these wavelengths with prescribed radiation temperatures. The atmosphere is optically thick in the 2-1, 3-1, 3-2 and c-1 transitions. Three stages of approximation are treated: (1) radiative detailed balance in the 2-1, 3-1 and 3-2 transitions, (2) radiative detailed balance in the 3-1 and 3-2 transitions, and (3) all transitions out of detailed balance. The solution of this problem is nontrivial and presents sufficient difficulty to have caused the failure of at least one rather standard technique. The problem is thus a good archetype against which new methods or new implementations of old methods may be tested.

  9. On the tumbling toast problem

    NASA Astrophysics Data System (ADS)

    Borghi, Riccardo

    2012-09-01

    A didactical revisitation of the so-called tumbling toast problem is presented here. The numerical solution of the related Newton's equations has been found in the space domain, without resorting to the complete time-based law of motion, with a considerable reduction of the mathematical complexity of the problem. This could allow the effect of the different physical mechanisms ruling the overall dynamics to be appreciated in a more transparent way, even by undergraduates. Moreover, the availability from the literature of experimental investigations carried out on tumbling toast allows us to propose different theoretical models of growing complexity in order to show the corresponding improvement of the agreement between theory and observation.

  10. Public health problems of urbanization.

    PubMed

    Mutatkar, R K

    1995-10-01

    Developing countries have been peasant societies. The cities in traditional societies have been pilgrimage centres, seats of administration and educational centres. These cities had homogeneous relationships with the villages. Industrialization has developed modern megacities whose way of life is heterogeneous with that in the villages. Rural poverty has pushed villagers to the cities, which were never planned to accommodate immigrants. Public health and social problems have arisen lowering the quality of life. Communicable diseases among the urban poor coexist with non-communicable diseases among the comparatively affluent. Problems of pollution, crime and chronic morbidity increase. The NGOs provide relief to the poor and needy but do nothing toward creating an infrastructure for balanced development. The election of women as a result of non-discriminatory legislation provides good ground for hope. PMID:8545672

  11. Two Problems with Table Saws

    ERIC Educational Resources Information Center

    Vautaw, William R.

    2008-01-01

    We solve two problems that arise when constructing picture frames using only a table saw. First, to cut a cove running the length of a board (given the width of the cove and the angle the cove makes with the face of the board) we calculate the height of the blade and the angle the board should be turned as it is passed over the blade. Second, to…

  12. Sleep problems in healthy preadolescents.

    PubMed

    Kahn, A; Van de Merckt, C; Rebuffat, E; Mozin, M J; Sottiaux, M; Blum, D; Hennart, P

    1989-09-01

    Few data currently exist concerning the sleep problems of preadolescents. A parent report questionnaire concerning sleep habits and problems was developed. The questionnaires were completed by the parents of 1000 unscreened elementary school children attending the third, fourth, and fifth grades. The schools were randomly selected from an urban area. Of the 1000 questionnaires, 972 were completed and could be used for statistical analysis. Among the parents, 24% reported sleeping poorly and 12% regularly relied on sedatives to induce sleep. Sleep difficulties lasting more than 6 months were present in 43% of the children. In 14% (132 of 972), sleep latency was longer than 30 minutes, and more than one complete arousal occurred during the night at least two nights per week. The following variables were seen among the poor sleepers: lower parental educational and professional status, parents who were more likely to be divorced or separated, and more noise or light in the rooms were they slept. They also presented a higher incidence of somnambulism, somniloquia, and night fears (nightmares and night terrors) than the children who slept well. Boys who slept poorly were significantly more likely to have insomniac fathers (P less than .010). Regular use of sedatives was described in 4% (5 of 132) of the children who slept poorly. Among the "poor sleepers," 21% (33 of 132) had failed 1 or more years at school. School achievement difficulties were encountered significantly more often among the poor sleepers than among the children without sleep problems (P = .001). Of the families with children suffering from sleep problems, 28% expressed a desire for counseling.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2788868

  13. Deadlock problem: a classifying bibliography

    SciTech Connect

    Zobel, D.

    1983-10-01

    The desire for a better utilisation of resources and an acceleration of computing introduced the concept of parallelism with all its difficulties. Soon the danger of eternal delays of processes was discovered and called deadlock. For almost twenty years a lot of publications have dealt with problems considering deadlocks or their environment. The author gives a classification of collected publications. He hopes to have found essential articles for nearly all the different topics fitting under the title 'deadlock'. 74 references.

  14. Solution of the Robbins problem.

    SciTech Connect

    McCune, W.; Mathematics and Computer Science

    1997-01-01

    In this article we show that the three equations known as commutativity, associativity, and the Robbins equation are a basis for the variety of Boolean algebras. The problem was posed by Herbert Robbins in the 1930s. The proof was found automatically by EQP, a theorem-proving program for equational logic. We present the proof and the search strategies that enabled the program to find the proof.

  15. Benchmark problems in computational aeroacoustics

    NASA Technical Reports Server (NTRS)

    Porter-Locklear, Freda

    1994-01-01

    A recent directive at NASA Langley is aimed at numerically predicting principal noise sources. During my summer stay, I worked with high-order ENO code, developed by Dr. Harold Atkins, for solving the unsteady compressible Navier-Stokes equations, as it applies to computational aeroacoustics (CAA). A CAA workshop, composed of six categories of benchmark problems, has been organized to test various numerical properties of code. My task was to determine the robustness of Atkins' code for these test problems. In one category, we tested the nonlinear wave propagation of the code for the one-dimensional Euler equations, with initial pressure, density, and velocity conditions. Using freestream boundary conditions, our results were plausible. In another category, we solved the linearized two-dimensional Euler equations to test the effectiveness of radiation boundary conditions. Here we utilized MAPLE to compute eigenvalues and eigenvectors of the Jacobian given variable and flux vectors. We experienced a minor problem with inflow and outflow boundary conditions. Next, we solved the quasi one dimensional unsteady flow equations with an incoming acoustic wave of amplitude 10(exp -6). The small amplitude sound wave was incident on a convergent-divergent nozzle. After finding a steady-state solution and then marching forward, our solution indicated that after 30 periods the acoustic wave had dissipated (a period is time required for sound wave to traverse one end of nozzle to other end).

  16. The zero exemplar distance problem.

    PubMed

    Jiang, Minghui

    2011-09-01

    Given two genomes with duplicate genes, Zero Exemplar Distance is the problem of deciding whether the two genomes can be reduced to the same genome without duplicate genes by deleting all but one copy of each gene in each genome. Blin, Fertin, Sikora, and Vialette recently proved that Zero Exemplar Distance for monochromosomal genomes is NP-hard even if each gene appears at most two times in each genome, thereby settling an important open question on genome rearrangement in the exemplar model. In this article, we give a very simple alternative proof of this result. We also study the problem Zero Exemplar Distance for multichromosomal genomes without gene order, and prove the analogous result that it is also NP-hard even if each gene appears at most two times in each genome. For the positive direction, we show that both variants of Zero Exemplar Distance admit polynomial-time algorithms if each gene appears exactly once in one genome and at least once in the other genome. In addition, we present a polynomial-time algorithm for the related problem Exemplar Longest Common Subsequence in the special case that each mandatory symbol appears exactly once in one input sequence and at least once in the other input sequence. This answers an open question of Bonizzoni et al. We also show that Zero Exemplar Distance for multichromosomal genomes without gene order is fixed-parameter tractable in the general case if the parameter is the maximum number of chromosomes in each genome. PMID:21899417

  17. Whither the global population problem.

    PubMed

    Greep, R O

    1998-02-15

    Growth of the human population has been underway for thousands of years and was never a problem until recently. It is now expanding exponentially, and today global population stands at nearly 6 billion with 97 million being added each year. Currently, overpopulation has led to serious social and environmental problems such as poverty, overcrowded slums, crime, terrorism, pollution of air and water, and depletion of the protective ozone layer. Warnings were sounded, but few listened. The enthusiasm once generated for solving the problem of too many people was short-lived. The press with puzzling abrogation of its responsibility to the public managed to allay all fears of population overgrowth. Two U.S. presidents welcomed such growth as a stimulus to economic development. Although modern contraceptives are safe, effective, and widely available, more are badly needed, but none are in the pipeline. Research is being hampered by hostile attitudes and by the high cost in time and money of bringing a new contraceptive to an uncertain market with the added threat of litigation. At the present rate of growth, the population will double in the next century. This is believed to be beyond the carrying capacity of our planet. Corrective measures by man or nature need to be undertaken. PMID:9514071

  18. Algorithmic Perspectives on Problem Formulations in MDO

    NASA Technical Reports Server (NTRS)

    Alexandrov, Natalia M.; Lewis, Robert Michael

    2000-01-01

    This work is concerned with an approach to formulating the multidisciplinary optimization (MDO) problem that reflects an algorithmic perspective on MDO problem solution. The algorithmic perspective focuses on formulating the problem in light of the abilities and inabilities of optimization algorithms, so that the resulting nonlinear programming problem can be solved reliably and efficiently by conventional optimization techniques. We propose a modular approach to formulating MDO problems that takes advantage of the problem structure, maximizes the autonomy of implementation, and allows for multiple easily interchangeable problem statements to be used depending on the available resources and the characteristics of the application problem.

  19. Fibonacci's Triangle: A Vehicle for Problem Solving.

    ERIC Educational Resources Information Center

    Ouellette, Hugh

    1979-01-01

    A method for solving certain types of problems is illustrated by problems related to Fibonacci's triangle. The method involves pattern recognition, generalizing, algebraic manipulation, and mathematical induction. (MP)

  20. Context in Mathematics Learning: Problems and Possibilities

    ERIC Educational Resources Information Center

    Lee, Ji-Eun

    2007-01-01

    This article presents an instructional idea that facilitates the students' active participation in the problem analysis process using insufficient or contradictory problem contexts. (Contains 1 figure.)